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MOF纳米材料的合成路线我选取的是Erik A. Flugel等在Journal of Materials Chemistry上发表的的Synthetic routes toward MOF nanomorphologies这篇论文。
然后在学习的过程中，还参考了一些中文文献和老师给的chemical review的那篇文章中的第六部分（MOF Crystals, Films/Membranes, and Composites）。
虽然是化学系的学生并且也选修了现代无机进展这门课，但是该篇文章还是让在阅读的过程中感到十分吃力，主要原因还是金属无机材料这个领域了解不够。
我将试着谈谈这篇文章的内容并给出自己的一点浅薄的体会。
本篇文章是和其他的综述流程一样，先是在简介中介绍了MOF的功能和最近的应用和本文的大致内容，然后进入正题，分为以下几部分：1.零维的MOF纳米晶体的制备；2.一维纳米结构晶体的制备；3.二维纳米结构晶体的制备；4.三位结构晶体的制备；5.杂合纳米结构晶体的制备；6.针对某一个晶体进行结构控制的机理的研究。
最后为文章的总述和致谢。
MOF是含氧或氮的有机配体与过渡金属通过自组装连接而形成的具有周期性网状结构的晶体材料。
其一般具有沸石和类沸石的结构。
在当今的社会中MOF因为其具有结构和孔道可以设计，可裁剪的特点并且表面积大而多孔而受到多个学科的重视。
MOF可以应用在吸收，气体贮存，传感器设计，集光，生物显影，药物传送和催化方面。
现在得到的纳米化的MOF材料，有着与普通固体材料截然不同的性质，比如因为其小尺寸而具有的干涉和散射的光学性质，比如在生物方面展现了更长时间的血浆循环时间，有些甚至可以在淋巴中进行传送。
MOF材料的形态也是至关重要的。
球形保证了一致的消融速度因而能够作为药物缓蚀剂。
而不是球形的或者各向异性的因为其边缘处和角落处的活性而具有催化功能，MOF的膜或者薄片对于气体的分离和探测是很重要的。
今年的工作汇报计划英语Outline:I. IntroductionA. Greeting and purpose of the reportB. Overview of the reporting periodII. Achievements and MilestonesA. Key objectives set at the beginning of the yearB. Progress and accomplishments in each objectiveC. Recognition of team members' contributionsIII. Challenges and Lessons LearnedA. Major obstacles encounteredB. Strategies implemented to overcome these challengesC. Insights gained from these experiencesIV. Financial PerformanceA. Revenue and profitability analysisB. Cost control measures and efficiency improvementsC. Comparison with industry benchmarksV. Departmental UpdatesA. Achievements and progress of each departmentB. Collaboration efforts and crossfunctional projectsC. Key personnel changes and team developmentVI. Market Trends and Competitive AnalysisA. Overview of market conditions and industry trendsB. Positioning of the company within the marketC. Analysis of competitors and their performanceVII. Future Outlook and Strategic InitiativesA. Goals and objectives for the upcoming yearB. Strategic plans and initiatives to achieve these goalsC. Potential risks and mitigation strategiesVIII. ConclusionA. Summary of the year's performanceB. Appreciation to all stakeholdersC. Call to action for the upcoming yearPlease find below the first part of the work report:I. IntroductionA. Greeting and purpose of the reportLadies and gentlemen, esteemed colleagues, and esteemed stakeholders, I present to you the annual work report for this year. The purpose of this report is to provide a comprehensive overview of our achievements, challenges, financial performance, and strategic initiatives throughout the year. It aims to outline the progress we have made and set the stage for the upcoming year's goals and objectives.B. Overview of the reporting periodThe reporting period covers the duration from January 1st to December 31st of this year. It has been a year marked by significant changes, both within our organization and in the external business environment. Despite the challenges faced, we have(strived to maintain our growth momentum and deliver value to our customers, employees, and shareholders.II. Achievements and MilestonesA. Key objectives set at the beginning of the yearAt the start of the year, we established several key objectives to drive our company's growth and success. These objectives encompassed various aspects, including revenue targets, market expansion, product development, and operational efficiency.B. Progress and accomplishments in each objective1. Revenue targets: We are pleased to report that we have exceeded our revenue targets for the year, achieving a yearonyear growth of XX%. This success is attributed to the collective efforts of our sales, marketing, and customer service teams.2. Market expansion: Through strategic partnerships and aggressive market penetration, we have successfully expanded our presence in key 地理 markets, including North America, Europe, and Asia Pacific.3. Product development: Our R&D team has launched severalinnovative products this year, receiving positive feedback from customers and industry experts. These new products have contributed to an XX% increase in our product portfolio.4. Operational efficiency: By implementing lean management practices and optimizing our supply chain, we have improved operational efficiency by XX%. This has resulted in cost savings and enhanced customer satisfaction.C. Recognition of team members' contributionsThe achievements mentioned above would not have been possible without the dedication and hard work of our team members. I would like to take this opportunity to recognize and appreciate each and every one of you for your invaluable contributions to the company's success. Your commitment and passion are the driving forces behind our accomplishments.To be continued:III. Challenges and Lessons LearnedA. Major obstacles encounteredIn the course of the year, we faced several significant challenges that tested our resilience and adaptability. The economic downturn, coupled with the global health crisis, presented unprecedented difficulties in the marketplace. Supply chain disruptions, travel restrictions, and shifts inconsumer behavior all posed threats to our business operations.B. Strategies implemented to overcome these challengesTo navigate through these rough waters, we adopted a variety of strategies. We invested in diversifying our supply chain to reduce dependency on singlesource suppliers, which helped mitigate the impact of disruptions. Additionally, we quickly transitioned to remote work arrangements, ensuring business continuity while prioritizing the health and safety of our employees. We also leveraged digital tools and platforms to maintain communication and collaboration across teams.C. Insights gained from these experiencesThe challenges we faced have provided us with valuable insights. We have learned the importance of agility and innovation in the face of adversity. The need for robust digital infrastructure and a skilled remote workforce has become clearer than ever. These lessons will inform our strategic planning and decisionmaking in the future.IV. Financial PerformanceA. Revenue and profitability analysisDespite the challenges, we are proud to report a positive financial performance for the year. Our revenue growth outpaced the industry average, and we achieved a profit margin that exceeded our projections. This success is a testament to the effective cost management and revenue generation strategies implemented acrossthe organization.B. Cost control measures and efficiency improvementsWe have implemented stringent cost control measures without compromising on the quality of our products and services. Through efficient resource allocation and process improvements, we have reduced unnecessary expenses and improved our bottom line. Our focus on lean principles has led to a more streamlined operation and a stronger financial position.C. Comparison with industry benchmarksOur financial performance stands out when compared to industry benchmarks. We have outperformed our competitors in key financial metrics, positioning us as a leader in the market. This is a direct result of our commitment to excellence and our ability to adapt to the changing business landscape.V. Departmental UpdatesA. Achievements and progress of each departmentEach department has made significant strides towards achieving their individual goals. Our sales department has successfully penetrated new markets and secured strategic partnerships. The marketing department has effectively enhanced our brand visibility, leading to increased customer engagement. The product development team has not only launched innovative products but also improved existing offeringsbased on customer feedback.B. Collaboration efforts and crossfunctional projects Crossfunctional collaboration has been a key focus area for us this year. We have initiated several projects that bring together teams from different departments, fostering a culture of cooperation and innovation. These efforts have resulted in more cohesive strategies and a unified approach towards problemsolving.C. Key personnel changes and team developmentWe have seen some key personnel changes this year, with new leadership taking over critical roles. These changes have brought fresh perspectives and renewed energy to the team. We have also invested in training and development programs to enhance the skills of our employees, ensuring they are equipped to handle future challenges.To be continued:VI. Market Trends and Competitive AnalysisA. Overview of market conditions and industry trendsThe market conditions this year have been dynamic and challenging. The industry has seen rapid technological advancements, shifting consumer preferences, and increased competition. Digital transformation has been a key trend, with companies investing heavily in AI, IoT, and cloud technologies to stay ahead. Additionally,sustainability and social responsibility have become important factors influencing consumer choices and business strategies.B. Positioning of the company within the marketOur company has strategically positioned itself to capitalize on these trends. We have embraced digital transformation by integrating cuttingedge technologies into our operations and product offerings. Our commitment to sustainability has also been a differentiator, helping us attract environmentally conscious customers and gain a competitive edge.C. Analysis of competitors and their performanceWe have closely monitored the performance of our competitors to understand our market position. While some have struggled to adapt to the changing landscape, others have made significant strides. Our competitive analysis has revealed areas where we can further improve our products and services. We have identified opportunities to differentiate ourselves through superior customer service, product innovation, and strategic partnerships.VII. Future Outlook and Strategic InitiativesA. Goals and objectives for the upcoming yearLooking ahead, we have set ambitious goals for the upcoming year. We aim to achieve a XX% increase in revenue by entering new markets and expanding our product lines. We also plan to enhance our operationalefficiency by an additional XX% through continuous process improvements and technology adoption.B. Strategic plans and initiatives to achieve these goalsTo achieve these goals, we have developed a series of strategic initiatives. We will invest in research and development to accelerate product innovation and maintain our technological leadership. We will also focus on strengthening our digital marketing efforts to increase brand awareness and attract new customers. Collaborative partnerships and strategic alliances will be key to our market expansion plans.C. Potential risks and mitigation strategiesWe recognize that the business environment is fraught with risks. Economic uncertainties, regulatory changes, and competitive threats are among the challenges we may face. To mitigate these risks, we will diversify our revenue streams, maintain a robust financial cushion, and stay agile in our decisionmaking processes. We will also continue to monitor market trends and adjust our strategies accordingly.VIII. ConclusionA. Summary of the year's performanceIn summary, this year has been a testament to the resilience and innovation of our organization. Despite the challenges, we have achieved remarkable success in revenue growth, market expansion, and product development. Our financial performance is a reflection of ourcommitment to efficiency and customer satisfaction.B. Appreciation to all stakeholdersI would like to express my deepest gratitude to all our stakeholders, including our employees, customers, suppliers, and investors. Your support and trust in our company have been instrumental in our success.C. Call to action for the upcoming yearAs we move forward, we must continue to embrace change, innovate, and collaborate. The upcoming year presents new opportunities for growth and success. I urge each and every one of us to remain focused, committed, and adaptable as we strive to achieve our goals and take our company to new heights.This concludes our annual work report. Thank you for your attention and dedication throughout the year. Together, we will continue to build a brighter future for our organization.。
育儿知识英语Raising a child is like embarking on an incredible journey, full of surprises, joys, and a few bumps along the way. And when ites to parenting knowledge in English, it can seem like a whole new world to explore.Let's start with something simple - talking to your baby in English from the very beginning. It's not about making them recite Shakespeare right away. It's like planting a little seed. You don't expect a huge oak tree overnight. When you coo and babble to your infant in English, you're introducing them to the sounds, the rhythm of the language. You can say things like "Good morning, sunshine" when you wake them up. It's just a warm, friendly way to start their day and get them used to the language.Reading English books to your kids is another great tip. Picture books are wonderful. They're like little windows into a magical world. You sit down with your child, open the book, and start reading. Point at the pictures and say the words. For example, if there's a picture of a cat, you say "cat". It's so much fun. And don't worry if you don't have a perfect accent. It's not about that. It's about sharing the love for the language.Now, let's talk about songs. English nursery rhymes are like little musical treats for kids. "Twinkle, Twinkle, Little Star" is a classic. Sing it with your child. They'll love the melody, and they'll start to pick up the words. It's like they're learning while having a party. You can make funny voices, dance around while singing. It makes the whole learning process so enjoyable.As your child gets older, you can start having simple conversations in English. It's like having a secret code between the two of you. Ask them how their day was. "Did you have a great day at school?" or "What did you do in the park today?" Encourage them to answer in English. And if they make mistakes, don't scold them. Mistakes are like little stepping stones. They help us move forward. Just gently correct them and keep the conversation going.Immersion is also a key factor. If possible, surround your child with English. Maybe you can watch English - speaking cartoons together. Cartoons are like a colorful world of imagination. Characters like Peppa Pig can be great friends for your child while they learn English. They'll hear the language in a natural context, just like they hear their native language at home.When ites to grammar, don't make it a big, scary monster. Grammar is like the skeleton of the language, but we don't need to show the skeleton right away. Start with simple sentences and phrases. Let your child get a feel for how the language flows. As they grow, they'll gradually understand moreplex grammar rules.Another aspect is writing. Start with simple things like drawing and writing the names of objects in English. It's like leaving little English footprints everywhere. You can make a little English journal for your child. Let them draw a picture of their day and write a few words about it.Teaching parenting knowledge in English is not about forcing your child to be a language prodigy. It's about opening a door to a new world, a world full of opportunities. It's like giving them a new set of keys to unlock different cultures, make new friends, and explore new ideas. You're building a bridge for them to cross into a broader universe.In conclusion, parenting knowledge in English is all about making it fun, natural, and a part of your daily life with your child. There's no one - size - fits - all approach. Every child is different, and every family has their own rhythm. So just enjoy the process, and watch your child grow and thrive in this new language adventure.。
COMPONENTS组成：1.Car body车身It is to accommodate passengers and the driver.这是为了容纳乘客和司机。
Meanwhile, it is the basic component to connect to other devices or car bodies.同时，它是连接到其他设备或车身的基本部件。
For the purpose of meeting the strength requirement while keeping the self-weight at its lowest. 为了满足强度要求，同时保持自重最低。
Integrated steel structure or light metal structure is adopted.采用整体式钢结构或轻型金属结构。
It usually comprises of the floor, the roof, sides and end walls.它通常包括地板、屋顶、侧壁和端壁。
2. Bogies转向架Motor and trailer bogies are located between the car body and the track, to drag and guide the vehicles moving along the track.汽车和拖车转向架位于车体与轨道之间，拖曳和引导车辆沿轨道运动。
They cab bear and transfer a variety of load from lines and the car body, easing its dynamic action.他们从线路和车体上承担和传递各种载荷，减轻其动力作用。
It usually comprises of frame, spring suspension, wheel axle box and brake devices, etc.它通常包括车架、弹簧悬架、车轮轴箱和制动装置等。
Airport Handling ManualEffective 1 January—31 December 201838NOTICEDISCLAIMER. The information contained in thispublication is subject to constant review in the lightof changing government requirements and regula-tions. No subscriber or other reader should act onthe basis of any such information without referringto applicable laws and regulations and/or withouttak ing appropriate professional advice. Althoughevery effort has been made to ensure accuracy, theInternational Air Transport Association shall not beheld responsible for any loss or damage caused byerrors, omissions, misprints or misinterpretation ofthe contents hereof. Furthermore, the InternationalAir Transport Association expressly disclaims anyand all liability to any person or entity, whether apurchaser of this publication or not, in respect ofanything done or omitted, and the consequencesof anything done or omitted, by any such person orentity in reliance on the contents of this publication.Opinions expressed in advertisements appearing inthis publication are the advertiser’s opinions and donot necessarily reflect those of IATA. The mentionof specific companies or products in advertisementdoes not imply that they are endorsed or recom-mended by IATA in preference to others of a simi-lar nature which are not mentioned or advertised.© International Air Transport Association. AllRights Reserved. No part of this publication maybe reproduced, recast, reformatted or trans-mitted in any form by any means, electronic ormechanical, including photocopying, record-ing or any information storage and retrieval sys-tem, without the prior written permission from:Senior Vice PresidentAirport, Passenger, Cargo and SecurityInternational Air Transport Association800 Place VictoriaP.O. Box 113Montreal, QuebecCANADA H4Z 1M1Airport Handling ManualMaterial No.: 9343-38ISBN 978-92-9229-505-9© 2017 International Air Transport Association. All rights reserved.TABLE OF CONTENTSPage Preface (xv)Introduction (xvii)General (1)AHM001Chapter0—Record of Revisions (1)AHM011Standard Classification and Numbering for Members Airport Handling Manuals (2)AHM012Office Function Designators for Airport Passenger and Baggage Handling (30)AHM020Guidelines for the Establishment of Airline Operators Committees (31)AHM021Guidelines for Establishing Aircraft Ground Times (34)AHM050Aircraft Emergency Procedures (35)AHM070E-Invoicing Standards (53)Chapter1—PASSENGER HANDLING (91)AHM100Chapter1—Record of Revisions (91)AHM110Involuntary Change of Carrier,Routing,Class or Type of Fare (92)AHM112Denied Boarding Compensation (98)AHM120Inadmissible Passengers and Deportees (99)AHM140Items Removed from a Passenger's Possession by Security Personnel (101)AHM141Hold Loading of Duty-Free Goods (102)AHM170Dangerous Goods in Passenger Baggage (103)AHM176Recommendations for the Handling of Passengers with Reduced Mobility(PRM) (105)AHM176A Acceptance and Carriage of Passengers with Reduced Mobility(PRM) (106)AHM180Carriage of Passengers with Communicable Diseases (114)AHM181General Guidelines for Passenger Agents in Case of SuspectedCommunicable Disease (115)Chapter2—BAGGAGE HANDLING (117)AHM200Chapter2—Record of Revisions (117)AHM210Local Baggage Committees (118)AHM211Airport Operating Rules (124)Airport Handling ManualPageChapter2—BAGGAGE HANDLING(continued)AHM212Interline Connecting Time Intervals—Passenger and Checked Baggage (126)AHM213Form of Interline Baggage Tags (128)AHM214Use of the10Digit Licence Plate (135)AHM215Found and Unclaimed Checked Baggage (136)AHM216On-Hand Baggage Summary Tag (138)AHM217Forwarding Mishandled Baggage (139)AHM218Dangerous Goods in Passengers'Baggage (141)AHM219Acceptance of Firearms and Other Weapons and Small Calibre Ammunition (142)AHM221Acceptance of Power Driven Wheelchairs or Other Battery Powered Mobility Aidsas Checked Baggage (143)AHM222Passenger/Baggage Reconciliation Procedures (144)AHM223Licence Plate Fallback Sortation Tags (151)AHM224Baggage Taken in Error (154)AHM225Baggage Irregularity Report (156)AHM226Tracing Unchecked Baggage and Handling Damage to Checked and UncheckedBaggage (159)AHM230Baggage Theft and Pilferage Prevention (161)AHM231Carriage of Carry-On Baggage (164)AHM232Handling of Security Removed Items (168)AHM240Baggage Codes for Identifying ULD Contents and/or Bulk-Loaded Baggage (169)Chapter3—CARGO/MAIL HANDLING (171)AHM300Chapter3—Record of Revisions (171)AHM310Preparation for Loading of Cargo (172)AHM311Securing of Load (174)AHM312Collection Sacks and Bags (177)AHM320Handling of Damaged Cargo (178)AHM321Handling of Pilfered Cargo (179)AHM322Handling Wet Cargo (180)AHM330Handling Perishable Cargo (182)AHM331Handling and Protection of Valuable Cargo (184)AHM332Handling and Stowage of Live Animals (188)AHM333Handling of Human Remains (190)Table of ContentsPageChapter3—CARGO/MAIL HANDLING(continued)AHM340Acceptance Standards for the Interchange of Transferred Unit Load Devices (191)AHM345Handling of Battery Operated Wheelchairs/Mobility AIDS as Checked Baggage (197)AHM350Mail Handling (199)AHM351Mail Documents (203)AHM353Handling of Found Mail (218)AHM354Handling of Damaged Mail (219)AHM355Mail Security (220)AHM356Mail Safety (221)AHM357Mail Irregularity Message (222)AHM360Company Mail (224)AHM380Aircraft Documents Stowage (225)AHM381Special Load—Notification to Captain(General) (226)AHM382Special Load—Notification to Captain(EDP Format and NOTOC Service) (231)AHM383Special Load—Notification to Captain(EDP NOTOC Summary) (243)AHM384NOTOC Message(NTM) (246)Chapter4—AIRCRAFT HANDLING AND LOADING (251)AHM400Chapter4—Record of Revisions (251)AHM411Provision and Carriage of Loading Accessories (252)AHM420Tagging of Unit Load Devices (253)AHM421Storage of Unit Load Devices (263)AHM422Control of Transferred Unit Load Devices (268)AHM423Unit Load Device Stock Check Message (273)AHM424Unit Load Device Control Message (275)AHM425Continued Airworthiness of Unit Load Devices (279)AHM426ULD Buildup and Breakdown (283)AHM427ULD Transportation (292)AHM430Operating of Aircraft Doors (295)AHM431Aircraft Ground Stability—Tipping (296)AHM440Potable Water Servicing (297)AHM441Aircraft Toilet Servicing (309)Airport Handling ManualPageChapter4—AIRCRAFT HANDLING AND LOADING(continued)AHM450Standardisation of Gravity Forces against which Load must be Restrained (310)AHM451Technical Malfunctions Limiting Load on Aircraft (311)AHM453Handling/Bulk Loading of Heavy Items (312)AHM454Handling and Loading of Big Overhang Items (313)AHM455Non CLS Restrained ULD (316)AHM460Guidelines for Turnround Plan (323)AHM462Safe Operating Practices in Aircraft Handling (324)AHM463Safety Considerations for Aircraft Movement Operations (337)AHM465Foreign Object Damage(FOD)Prevention Program (340)Chapter5—LOAD CONTROL (343)AHM500Chapter5—Record of Revisions (343)AHM501Terms and Definitions (345)AHM503Recommended Requirements for a New Departure Control System (351)AHM504Departure Control System Evaluation Checklist (356)AHM505Designation of Aircraft Holds,Compartments,Bays and Cabin (362)AHM510Handling/Load Information Codes to be Used on Traffic Documents and Messages (368)AHM513Aircraft Structural Loading Limitations (377)AHM514EDP Loading Instruction/Report (388)AHM515Manual Loading Instruction/Report (404)AHM516Manual Loadsheet (416)AHM517EDP Loadsheet (430)AHM518ACARS Transmitted Loadsheet (439)AHM519Balance Calculation Methods (446)AHM520Aircraft Equipped with a CG Targeting System (451)AHM530Weights for Passengers and Baggage (452)AHM531Procedure for Establishing Standard Weights for Passengers and Baggage (453)AHM533Passengers Occupying Crew Seats (459)AHM534Weight Control of Load (460)AHM536Equipment in Compartments Procedure (461)AHM537Ballast (466)Table of ContentsPageChapter5—LOAD CONTROL(continued)AHM540Aircraft Unit Load Device—Weight and Balance Control (467)AHM550Pilot in Command's Approval of the Loadsheet (468)AHM551Last Minute Changes on Loadsheet (469)AHM561Departure Control System,Carrier's Approval Procedures (471)AHM562Semi-Permanent Data Exchange Message(DEM) (473)AHM564Migration from AHM560to AHM565 (480)AHM565EDP Semi-Permanent Data Exchange for New Generation Departure Control Systems (500)AHM570Automated Information Exchange between Check-in and Load Control Systems (602)AHM571Passenger and Baggage Details for Weight and Balance Report(PWR) (608)AHM580Unit Load Device/Bulk Load Weight Statement (613)AHM581Unit Load Device/Bulk Load Weight Signal (615)AHM583Loadmessage (619)AHM587Container/Pallet Distribution Message (623)AHM588Statistical Load Summary (628)AHM590Load Control Procedures and Loading Supervision Responsibilities (631)AHM591Weight and Balance Load Control and Loading Supervision Training and Qualifications (635)Chapter6—MANAGEMENT AND SAFETY (641)AHM600Chapter6—Record of Revisions (641)AHM610Guidelines for a Safety Management System (642)AHM611Airside Personnel:Responsibilities,Training and Qualifications (657)AHM612Airside Performance Evaluation Program (664)AHM615Quality Management System (683)AHM616Human Factors Program (715)AHM619Guidelines for Producing Emergency Response Plan(s) (731)AHM620Guidelines for an Emergency Management System (733)AHM621Security Management (736)AHM633Guidelines for the Handling of Emergencies Requiring the Evacuation of an Aircraft During Ground Handling (743)AHM650Ramp Incident/Accident Reporting (745)AHM652Recommendations for Airside Safety Investigations (750)AHM660Carrier Guidelines for Calculating Aircraft Ground Accident Costs (759)Airport Handling ManualChapter7—AIRCRAFT MOVEMENT CONTROL (761)AHM700Chapter7—Record of Revisions (761)AHM710Standards for Message Formats (762)AHM711Standards for Message Corrections (764)AHM730Codes to be Used in Aircraft Movement and Diversion Messages (765)AHM731Enhanced Reporting on ATFM Delays by the Use of Sub Codes (771)AHM780Aircraft Movement Message (774)AHM781Aircraft Diversion Message (786)AHM782Fuel Monitoring Message (790)AHM783Request Information Message (795)AHM784Gate Message (797)AHM785Aircraft Initiated Movement Message(MVA) (802)AHM790Operational Aircraft Registration(OAR)Message (807)Chapter8—GROUND HANDLING AGREEMENTS (811)AHM800Chapter8—Record of Revisions (811)AHM801Introduction to and Comments on IATA Standard Ground Handling Agreement(SGHA) (812)AHM803Service Level Agreement Example (817)AHM810IATA Standard Ground Handling Agreement (828)AHM811Yellow Pages (871)AHM813Truck Handling (872)AHM815Standard Transportation Documents Service Main Agreement (873)AHM817Standard Training Agreement (887)AHM830Ground Handling Charge Note (891)AHM840Model Agreement for Electronic Data Interchange(EDI) (894)Chapter9—AIRPORT HANDLING GROUND SUPPORT EQUIPMENT SPECIFICATIONS (911)AHM900Chapter9—Record of Revisions (911)AHM901Functional Specifications (914)AHM904Aircraft Servicing Points and System Requirements (915)AIRBUS A300B2320-/B4/C4 (917)A300F4-600/-600C4 (920)A310–200/200C/300 (926)A318 (930)A319 (933)Table of ContentsPageChapter9—AIRPORT HANDLING GROUND SUPPORT EQUIPMENT SPECIFICATIONS(continued) AHM904Aircraft Doors,Servicing Points and System Requirements for the Use of Ground Support Equipment(continued)A320 (936)A321 (940)A330-200F (943)A330-300 (948)A340-200 (951)A340-300 (955)A340-500 (959)A340-600 (962)Airbus350900passenger (965)AIRBUS A380-800/-800F (996)ATR42100/200 (999)ATR72 (1000)AVRO RJ70 (1001)AVRO RJ85 (1002)AVRO RJ100 (1003)B727-200 (1004)B737–200/200C (1008)B737-300,400,-500 (1010)B737-400 (1013)B737-500 (1015)B737-600,-700,-700C (1017)B737-700 (1020)B737-800 (1022)B737-900 (1026)B747–100SF/200C/200F (1028)B747–400/400C (1030)B757–200 (1038)B757–300 (1040)Airport Handling ManualPageChapter9—AIRPORT HANDLING GROUND SUPPORT EQUIPMENT SPECIFICATIONS(continued) AHM904Aircraft Doors,Servicing Points and System Requirements for the Use of Ground Support Equipment(continued)B767—200/200ER (1041)B767—300/300ER (1044)B767—400ER (1048)B777–200/200LR (1051)B777–300/300ER (1055)Boeing787800passenger (1059)BAe ATP(J61) (1067)Bombardier CS100 (1068)Bombardier CS300 (1072)CL-65(CRJ100/200) (1076)DC8–40/50F SERIES (1077)DC8–61/61F (1079)DC8–62/62F (1081)DC8–63/63F (1083)DC9–15/21 (1085)DC9–32 (1086)DC9–41 (1087)DC9–51 (1088)DC10–10/10CF (1089)DC10–30/40,30/40CF (1091)EMBRAER EMB-135Regional Models (1092)EMBRAER EMB-145Regional Models (1094)Embraer170 (1096)Embraer175 (1098)Embraer190 (1100)Embraer195 (1102)FOKKER50(F27Mk050) (1104)FOKKER50(F27Mk0502) (1106)Chapter9—AIRPORT HANDLING GROUND SUPPORT EQUIPMENT SPECIFICATIONS(continued) AHM904Aircraft Doors,Servicing Points and System Requirements for the Use of Ground Support Equipment(continued)FOKKER70(F28Mk0070) (1108)FOKKER100(F28Mk0100) (1110)FOKKER100(F28Mk0100) (1112)IL-76T (1114)MD-11 (1116)MD–80SERIES (1118)SAAB2000 (1119)SAAB SF-340 (1120)TU-204 (1122)AHM905Reference Material for Civil Aircraft Ground Support Equipment (1125)AHM905A Cross Reference of IATA Documents with SAE,CEN,and ISO (1129)AHM909Summary of Unit Load Device Capacity and Dimensions (1131)AHM910Basic Requirements for Aircraft Ground Support Equipment (1132)AHM911Ground Support Equipment Requirements for Compatibility with Aircraft Unit Load Devices (1136)AHM912Standard Forklift Pockets Dimensions and Characteristics for Forkliftable General Support Equipment (1138)AHM913Basic Safety Requirements for Aircraft Ground Support Equipment (1140)AHM914Compatibility of Ground Support Equipment with Aircraft Types (1145)AHM915Standard Controls (1147)AHM916Basic Requirements for Towing Vehicle Interface(HITCH) (1161)AHM917Basic Minimum Preventive Maintenance Program/Schedule (1162)AHM920Functional Specification for Self-Propelled Telescopic Passenger Stairs (1164)AHM920A Functional Specification for Towed Passenger Stairs (1167)AHM921Functional Specification for Boarding/De-Boarding Vehicle for Passengers withReduced Mobility(PRM) (1169)AHM922Basic Requirements for Passenger Boarding Bridge Aircraft Interface (1174)AHM923Functional Specification for Elevating Passenger Transfer Vehicle (1180)AHM924Functional Specification for Heavy Item Lift Platform (1183)AHM925Functional Specification for a Self-Propelled Conveyor-Belt Loader (1184)AHM925A Functional Specification for a Self-Propelled Ground Based in-Plane LoadingSystem for Bulk Cargo (1187)Chapter9—AIRPORT HANDLING GROUND SUPPORT EQUIPMENT SPECIFICATIONS(continued) AHM925B Functional Specification for a Towed Conveyor-Belt Loader (1190)AHM926Functional Specification for Upper Deck Catering Vehicle (1193)AHM927Functional Specification for Main Deck Catering Vehicle (1197)AHM930Functional Specification for an Upper Deck Container/Pallet Loader (1201)AHM931Functional Specification for Lower Deck Container/Pallet Loader (1203)AHM932Functional Specification for a Main Deck Container/Pallet Loader (1206)AHM933Functional Specification of a Powered Extension Platform to Lower Deck/Container/ Pallet Loader (1209)AHM934Functional Specification for a Narrow Body Lower Deck Single Platform Loader (1211)AHM934A Functional Specification for a Single Platform Slave Loader Bed for Lower DeckLoading Operations (1213)AHM936Functional Specification for a Container Loader Transporter (1215)AHM938Functional Specification for a Large Capacity Freighter and Combi Aircraft TailStanchion (1218)AHM939Functional Specification for a Transfer Platform Lift (1220)AHM941Functional Specification for Equipment Used for Establishing the Weight of aULD/BULK Load (1222)AHM942Functional Specification for Storage Equipment Used for Unit Load Devices (1224)AHM950Functional Specification for an Airport Passenger Bus (1225)AHM951Functional Specification for a Crew Transportation Vehicle (1227)AHM953Functional Specifications for a Valuable Cargo Vehicle (1229)AHM954Functional Specification for an Aircraft Washing Machine (1230)AHM955Functional Specification for an Aircraft Nose Gear Towbar Tractor (1232)AHM956Functional Specification for Main Gear Towbarless Tractor (1235)AHM957Functional Specification for Nose Gear Towbarless Tractor (1237)AHM958Functional Specification for an Aircraft Towbar (1240)AHM960Functional Specification for Unit Load Device Transport Vehicle (1242)AHM961Functional Specification for a Roller System for Unit Load Device Transportation on Trucks (1245)AHM962Functional Specification for a Rollerised Platform for the Transportation of Twenty Foot Unit Load Devices that Interfaces with Trucks Equipped to Accept Freight ContainersComplying with ISO668:1988 (1247)AHM963Functional Specification for a Baggage/Cargo Cart (1249)AHM965Functional Specification for a Lower Deck Container Turntable Dolly (1250)AHM966Functional Specification for a Pallet Dolly (1252)Chapter9—AIRPORT HANDLING GROUND SUPPORT EQUIPMENT SPECIFICATIONS(continued) AHM967Functional Specification for a Twenty Foot Unit Load Device Dolly (1254)AHM968Functional Specification for Ramp Equipment Tractors (1256)AHM969Functional Specification for a Pallet/Container Transporter (1257)AHM970Functional Specification for a Self-Propelled Potable Water Vehicle with Rear orFront Servicing (1259)AHM971Functional Specification for a Self-Propelled Lavatory Service Vehicle with Rear orFront Servicing (1262)AHM972Functional Specifications for a Ground Power Unit for Aircraft Electrical System (1265)AHM973Functional Specification for a Towed Aircraft Ground Heater (1269)AHM974Functional Specification for Aircraft Air Conditioning(Cooling)Unit (1272)AHM975Functional Specifications for Self-Propelled Aircraft De-Icing/Anti-Icing Unit (1274)AHM976Functional Specifications for an Air Start Unit (1278)AHM977Functional Specification for a Towed De-Icing/Anti-Icing Unit (1280)AHM978Functional Specification for a Towed Lavatory Service Cart (1283)AHM979Functional Specification for a Towed Boarding/De-Boarding Device for Passengers with Reduced Mobility(PRM)for Commuter-Type Aircraft (1285)AHM980Functional Specification for a Self-Propelled Petrol/Diesel Refueling Vehicle forGround Support Equipment (1287)AHM981Functional Specification for a Towed Potable Water Service Cart (1289)AHM990Guidelines for Preventative Maintenance of Aircraft Towbars (1291)AHM994Criteria for Consideration of the Investment in Ground Support Equipment (1292)AHM995Basic Unit Load Device Handling System Requirements (1296)AHM997Functional Specification for Sub-Freezing Aircraft Air Conditioning Unit (1298)Chapter10—ENVIRONMENTAL SPECIFICATIONS FOR GROUND HANDLING OPERATIONS (1301)AHM1000Chapter10—Record of Revisions (1301)AHM1001Environmental Specifications for Ground Handling Operations (1302)AHM1002Environmental Impact on the Use of Ground Support Equipment (1303)AHM1003GSE Environmental Quality Audit (1305)AHM1004Guidelines for Calculating GSE Exhaust Emissions (1307)AHM1005Guidelines for an Environmental Management System (1308)Chapter11—GROUND OPERATIONS TRAINING PROGRAM (1311)AHM1100Chapter11—Record of Revisions (1311)AHM1110Ground Operations Training Program (1312)Appendix A—References (1347)Appendix B—Glossary (1379)Alphabetical List of AHM Titles (1387)IATA Strategic Partners..............................................................................................................................SP–1。
魔方英语作文The Rubik's Cube: A Journey Through Colorful ChallengesIn the realm of puzzles, few can match the allure and challenge of the Rubik's Cube. Invented by Ernő Rubik in 1974, this three-dimensional twisty puzzle has captured the imagination of people across the globe. It consists of a3x3x3 grid of colored squares, each representing a unique piece that can be rotated on three axes. The objective is to return the scrambled cube to its original state, where each face displays a uniform color.The Rubik's Cube is not merely a toy; it is a testament to human ingenuity and perseverance. Solving it requires a combination of logic, strategy, and sometimes even memorization. Many enthusiasts have developed various methods and algorithms to tackle the cube, ranging from the straightforward layer-by-layer approach to more complex techniques like the Fridrich Method.The journey to mastering the Rubik's Cube is akin to a personal quest. It starts with the initial bewilderment as one gazes upon the jumbled colors, followed by the gradual discovery of patterns and sequences. Each solved cube is a small victory, a moment of triumph that fuels the desire to improve and to challenge oneself further.Beyond the satisfaction of solving the puzzle, the Rubik'sCube also serves as a metaphor for problem-solving in life. Just as one must patiently manipulate the cube's pieces to achieve a solution, so too must we approach life's challenges with a methodical mindset. The cube teaches us the value of patience, the importance of strategy, and the joy of overcoming obstacles.Moreover, the Rubik's Cube has become a platform for competition and camaraderie. Speedcubing, the practice of solving the cube as quickly as possible, has turned into a competitive sport with its own community and events. World Cube Association (WCA) organizes competitions where cubers from all corners of the world gather to test their skills and share their passion.In conclusion, the Rubik's Cube is more than a puzzle; it is a symbol of intellectual exploration and a tool for personal growth. It challenges us to think critically, to persevere in the face of difficulty, and to celebrate our achievements. Whether one is a casual solver or a dedicated speedcuber, the cube offers a universal experience of learning, problem-solving, and the pursuit of mastery.。
3GPP TS 36.331 V13.2.0 (2016-06)Technical Specification3rd Generation Partnership Project;Technical Specification Group Radio Access Network;Evolved Universal Terrestrial Radio Access (E-UTRA);Radio Resource Control (RRC);Protocol specification(Release 13)The present document has been developed within the 3rd Generation Partnership Project (3GPP TM) and may be further elaborated for the purposes of 3GPP. The present document has not been subject to any approval process by the 3GPP Organizational Partners and shall not be implemented.This Specification is provided for future development work within 3GPP only. The Organizational Partners accept no liability for any use of this Specification. Specifications and reports for implementation of the 3GPP TM system should be obtained via the 3GPP Organizational Partners' Publications Offices.KeywordsUMTS, radio3GPPPostal address3GPP support office address650 Route des Lucioles - Sophia AntipolisValbonne - FRANCETel.: +33 4 92 94 42 00 Fax: +33 4 93 65 47 16InternetCopyright NotificationNo part may be reproduced except as authorized by written permission.The copyright and the foregoing restriction extend to reproduction in all media.© 2016, 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC).All rights reserved.UMTS™ is a Trade Mark of ETSI registered for the benefit of its members3GPP™ is a Trade Mark of ETSI registered for the benefit of its Members and of the 3GPP Organizational PartnersLTE™ is a Trade Mark of ETSI currently being registered for the benefit of its Members and of the 3GPP Organizational Partners GSM® and the GSM logo are registered and owned by the GSM AssociationBluetooth® is a Trade Mark of the Bluetooth SIG registered for the benefit of its membersContentsForeword (18)1Scope (19)2References (19)3Definitions, symbols and abbreviations (22)3.1Definitions (22)3.2Abbreviations (24)4General (27)4.1Introduction (27)4.2Architecture (28)4.2.1UE states and state transitions including inter RAT (28)4.2.2Signalling radio bearers (29)4.3Services (30)4.3.1Services provided to upper layers (30)4.3.2Services expected from lower layers (30)4.4Functions (30)5Procedures (32)5.1General (32)5.1.1Introduction (32)5.1.2General requirements (32)5.2System information (33)5.2.1Introduction (33)5.2.1.1General (33)5.2.1.2Scheduling (34)5.2.1.2a Scheduling for NB-IoT (34)5.2.1.3System information validity and notification of changes (35)5.2.1.4Indication of ETWS notification (36)5.2.1.5Indication of CMAS notification (37)5.2.1.6Notification of EAB parameters change (37)5.2.1.7Access Barring parameters change in NB-IoT (37)5.2.2System information acquisition (38)5.2.2.1General (38)5.2.2.2Initiation (38)5.2.2.3System information required by the UE (38)5.2.2.4System information acquisition by the UE (39)5.2.2.5Essential system information missing (42)5.2.2.6Actions upon reception of the MasterInformationBlock message (42)5.2.2.7Actions upon reception of the SystemInformationBlockType1 message (42)5.2.2.8Actions upon reception of SystemInformation messages (44)5.2.2.9Actions upon reception of SystemInformationBlockType2 (44)5.2.2.10Actions upon reception of SystemInformationBlockType3 (45)5.2.2.11Actions upon reception of SystemInformationBlockType4 (45)5.2.2.12Actions upon reception of SystemInformationBlockType5 (45)5.2.2.13Actions upon reception of SystemInformationBlockType6 (45)5.2.2.14Actions upon reception of SystemInformationBlockType7 (45)5.2.2.15Actions upon reception of SystemInformationBlockType8 (45)5.2.2.16Actions upon reception of SystemInformationBlockType9 (46)5.2.2.17Actions upon reception of SystemInformationBlockType10 (46)5.2.2.18Actions upon reception of SystemInformationBlockType11 (46)5.2.2.19Actions upon reception of SystemInformationBlockType12 (47)5.2.2.20Actions upon reception of SystemInformationBlockType13 (48)5.2.2.21Actions upon reception of SystemInformationBlockType14 (48)5.2.2.22Actions upon reception of SystemInformationBlockType15 (48)5.2.2.23Actions upon reception of SystemInformationBlockType16 (48)5.2.2.24Actions upon reception of SystemInformationBlockType17 (48)5.2.2.25Actions upon reception of SystemInformationBlockType18 (48)5.2.2.26Actions upon reception of SystemInformationBlockType19 (49)5.2.3Acquisition of an SI message (49)5.2.3a Acquisition of an SI message by BL UE or UE in CE or a NB-IoT UE (50)5.3Connection control (50)5.3.1Introduction (50)5.3.1.1RRC connection control (50)5.3.1.2Security (52)5.3.1.2a RN security (53)5.3.1.3Connected mode mobility (53)5.3.1.4Connection control in NB-IoT (54)5.3.2Paging (55)5.3.2.1General (55)5.3.2.2Initiation (55)5.3.2.3Reception of the Paging message by the UE (55)5.3.3RRC connection establishment (56)5.3.3.1General (56)5.3.3.1a Conditions for establishing RRC Connection for sidelink communication/ discovery (58)5.3.3.2Initiation (59)5.3.3.3Actions related to transmission of RRCConnectionRequest message (63)5.3.3.3a Actions related to transmission of RRCConnectionResumeRequest message (64)5.3.3.4Reception of the RRCConnectionSetup by the UE (64)5.3.3.4a Reception of the RRCConnectionResume by the UE (66)5.3.3.5Cell re-selection while T300, T302, T303, T305, T306, or T308 is running (68)5.3.3.6T300 expiry (68)5.3.3.7T302, T303, T305, T306, or T308 expiry or stop (69)5.3.3.8Reception of the RRCConnectionReject by the UE (70)5.3.3.9Abortion of RRC connection establishment (71)5.3.3.10Handling of SSAC related parameters (71)5.3.3.11Access barring check (72)5.3.3.12EAB check (73)5.3.3.13Access barring check for ACDC (73)5.3.3.14Access Barring check for NB-IoT (74)5.3.4Initial security activation (75)5.3.4.1General (75)5.3.4.2Initiation (76)5.3.4.3Reception of the SecurityModeCommand by the UE (76)5.3.5RRC connection reconfiguration (77)5.3.5.1General (77)5.3.5.2Initiation (77)5.3.5.3Reception of an RRCConnectionReconfiguration not including the mobilityControlInfo by theUE (77)5.3.5.4Reception of an RRCConnectionReconfiguration including the mobilityControlInfo by the UE(handover) (79)5.3.5.5Reconfiguration failure (83)5.3.5.6T304 expiry (handover failure) (83)5.3.5.7Void (84)5.3.5.7a T307 expiry (SCG change failure) (84)5.3.5.8Radio Configuration involving full configuration option (84)5.3.6Counter check (86)5.3.6.1General (86)5.3.6.2Initiation (86)5.3.6.3Reception of the CounterCheck message by the UE (86)5.3.7RRC connection re-establishment (87)5.3.7.1General (87)5.3.7.2Initiation (87)5.3.7.3Actions following cell selection while T311 is running (88)5.3.7.4Actions related to transmission of RRCConnectionReestablishmentRequest message (89)5.3.7.5Reception of the RRCConnectionReestablishment by the UE (89)5.3.7.6T311 expiry (91)5.3.7.7T301 expiry or selected cell no longer suitable (91)5.3.7.8Reception of RRCConnectionReestablishmentReject by the UE (91)5.3.8RRC connection release (92)5.3.8.1General (92)5.3.8.2Initiation (92)5.3.8.3Reception of the RRCConnectionRelease by the UE (92)5.3.8.4T320 expiry (93)5.3.9RRC connection release requested by upper layers (93)5.3.9.1General (93)5.3.9.2Initiation (93)5.3.10Radio resource configuration (93)5.3.10.0General (93)5.3.10.1SRB addition/ modification (94)5.3.10.2DRB release (95)5.3.10.3DRB addition/ modification (95)5.3.10.3a1DC specific DRB addition or reconfiguration (96)5.3.10.3a2LWA specific DRB addition or reconfiguration (98)5.3.10.3a3LWIP specific DRB addition or reconfiguration (98)5.3.10.3a SCell release (99)5.3.10.3b SCell addition/ modification (99)5.3.10.3c PSCell addition or modification (99)5.3.10.4MAC main reconfiguration (99)5.3.10.5Semi-persistent scheduling reconfiguration (100)5.3.10.6Physical channel reconfiguration (100)5.3.10.7Radio Link Failure Timers and Constants reconfiguration (101)5.3.10.8Time domain measurement resource restriction for serving cell (101)5.3.10.9Other configuration (102)5.3.10.10SCG reconfiguration (103)5.3.10.11SCG dedicated resource configuration (104)5.3.10.12Reconfiguration SCG or split DRB by drb-ToAddModList (105)5.3.10.13Neighbour cell information reconfiguration (105)5.3.10.14Void (105)5.3.10.15Sidelink dedicated configuration (105)5.3.10.16T370 expiry (106)5.3.11Radio link failure related actions (107)5.3.11.1Detection of physical layer problems in RRC_CONNECTED (107)5.3.11.2Recovery of physical layer problems (107)5.3.11.3Detection of radio link failure (107)5.3.12UE actions upon leaving RRC_CONNECTED (109)5.3.13UE actions upon PUCCH/ SRS release request (110)5.3.14Proximity indication (110)5.3.14.1General (110)5.3.14.2Initiation (111)5.3.14.3Actions related to transmission of ProximityIndication message (111)5.3.15Void (111)5.4Inter-RAT mobility (111)5.4.1Introduction (111)5.4.2Handover to E-UTRA (112)5.4.2.1General (112)5.4.2.2Initiation (112)5.4.2.3Reception of the RRCConnectionReconfiguration by the UE (112)5.4.2.4Reconfiguration failure (114)5.4.2.5T304 expiry (handover to E-UTRA failure) (114)5.4.3Mobility from E-UTRA (114)5.4.3.1General (114)5.4.3.2Initiation (115)5.4.3.3Reception of the MobilityFromEUTRACommand by the UE (115)5.4.3.4Successful completion of the mobility from E-UTRA (116)5.4.3.5Mobility from E-UTRA failure (117)5.4.4Handover from E-UTRA preparation request (CDMA2000) (117)5.4.4.1General (117)5.4.4.2Initiation (118)5.4.4.3Reception of the HandoverFromEUTRAPreparationRequest by the UE (118)5.4.5UL handover preparation transfer (CDMA2000) (118)5.4.5.1General (118)5.4.5.2Initiation (118)5.4.5.3Actions related to transmission of the ULHandoverPreparationTransfer message (119)5.4.5.4Failure to deliver the ULHandoverPreparationTransfer message (119)5.4.6Inter-RAT cell change order to E-UTRAN (119)5.4.6.1General (119)5.4.6.2Initiation (119)5.4.6.3UE fails to complete an inter-RAT cell change order (119)5.5Measurements (120)5.5.1Introduction (120)5.5.2Measurement configuration (121)5.5.2.1General (121)5.5.2.2Measurement identity removal (122)5.5.2.2a Measurement identity autonomous removal (122)5.5.2.3Measurement identity addition/ modification (123)5.5.2.4Measurement object removal (124)5.5.2.5Measurement object addition/ modification (124)5.5.2.6Reporting configuration removal (126)5.5.2.7Reporting configuration addition/ modification (127)5.5.2.8Quantity configuration (127)5.5.2.9Measurement gap configuration (127)5.5.2.10Discovery signals measurement timing configuration (128)5.5.2.11RSSI measurement timing configuration (128)5.5.3Performing measurements (128)5.5.3.1General (128)5.5.3.2Layer 3 filtering (131)5.5.4Measurement report triggering (131)5.5.4.1General (131)5.5.4.2Event A1 (Serving becomes better than threshold) (135)5.5.4.3Event A2 (Serving becomes worse than threshold) (136)5.5.4.4Event A3 (Neighbour becomes offset better than PCell/ PSCell) (136)5.5.4.5Event A4 (Neighbour becomes better than threshold) (137)5.5.4.6Event A5 (PCell/ PSCell becomes worse than threshold1 and neighbour becomes better thanthreshold2) (138)5.5.4.6a Event A6 (Neighbour becomes offset better than SCell) (139)5.5.4.7Event B1 (Inter RAT neighbour becomes better than threshold) (139)5.5.4.8Event B2 (PCell becomes worse than threshold1 and inter RAT neighbour becomes better thanthreshold2) (140)5.5.4.9Event C1 (CSI-RS resource becomes better than threshold) (141)5.5.4.10Event C2 (CSI-RS resource becomes offset better than reference CSI-RS resource) (141)5.5.4.11Event W1 (WLAN becomes better than a threshold) (142)5.5.4.12Event W2 (All WLAN inside WLAN mobility set becomes worse than threshold1 and a WLANoutside WLAN mobility set becomes better than threshold2) (142)5.5.4.13Event W3 (All WLAN inside WLAN mobility set becomes worse than a threshold) (143)5.5.5Measurement reporting (144)5.5.6Measurement related actions (148)5.5.6.1Actions upon handover and re-establishment (148)5.5.6.2Speed dependant scaling of measurement related parameters (149)5.5.7Inter-frequency RSTD measurement indication (149)5.5.7.1General (149)5.5.7.2Initiation (150)5.5.7.3Actions related to transmission of InterFreqRSTDMeasurementIndication message (150)5.6Other (150)5.6.0General (150)5.6.1DL information transfer (151)5.6.1.1General (151)5.6.1.2Initiation (151)5.6.1.3Reception of the DLInformationTransfer by the UE (151)5.6.2UL information transfer (151)5.6.2.1General (151)5.6.2.2Initiation (151)5.6.2.3Actions related to transmission of ULInformationTransfer message (152)5.6.2.4Failure to deliver ULInformationTransfer message (152)5.6.3UE capability transfer (152)5.6.3.1General (152)5.6.3.2Initiation (153)5.6.3.3Reception of the UECapabilityEnquiry by the UE (153)5.6.4CSFB to 1x Parameter transfer (157)5.6.4.1General (157)5.6.4.2Initiation (157)5.6.4.3Actions related to transmission of CSFBParametersRequestCDMA2000 message (157)5.6.4.4Reception of the CSFBParametersResponseCDMA2000 message (157)5.6.5UE Information (158)5.6.5.1General (158)5.6.5.2Initiation (158)5.6.5.3Reception of the UEInformationRequest message (158)5.6.6 Logged Measurement Configuration (159)5.6.6.1General (159)5.6.6.2Initiation (160)5.6.6.3Reception of the LoggedMeasurementConfiguration by the UE (160)5.6.6.4T330 expiry (160)5.6.7 Release of Logged Measurement Configuration (160)5.6.7.1General (160)5.6.7.2Initiation (160)5.6.8 Measurements logging (161)5.6.8.1General (161)5.6.8.2Initiation (161)5.6.9In-device coexistence indication (163)5.6.9.1General (163)5.6.9.2Initiation (164)5.6.9.3Actions related to transmission of InDeviceCoexIndication message (164)5.6.10UE Assistance Information (165)5.6.10.1General (165)5.6.10.2Initiation (166)5.6.10.3Actions related to transmission of UEAssistanceInformation message (166)5.6.11 Mobility history information (166)5.6.11.1General (166)5.6.11.2Initiation (166)5.6.12RAN-assisted WLAN interworking (167)5.6.12.1General (167)5.6.12.2Dedicated WLAN offload configuration (167)5.6.12.3WLAN offload RAN evaluation (167)5.6.12.4T350 expiry or stop (167)5.6.12.5Cell selection/ re-selection while T350 is running (168)5.6.13SCG failure information (168)5.6.13.1General (168)5.6.13.2Initiation (168)5.6.13.3Actions related to transmission of SCGFailureInformation message (168)5.6.14LTE-WLAN Aggregation (169)5.6.14.1Introduction (169)5.6.14.2Reception of LWA configuration (169)5.6.14.3Release of LWA configuration (170)5.6.15WLAN connection management (170)5.6.15.1Introduction (170)5.6.15.2WLAN connection status reporting (170)5.6.15.2.1General (170)5.6.15.2.2Initiation (171)5.6.15.2.3Actions related to transmission of WLANConnectionStatusReport message (171)5.6.15.3T351 Expiry (WLAN connection attempt timeout) (171)5.6.15.4WLAN status monitoring (171)5.6.16RAN controlled LTE-WLAN interworking (172)5.6.16.1General (172)5.6.16.2WLAN traffic steering command (172)5.6.17LTE-WLAN aggregation with IPsec tunnel (173)5.6.17.1General (173)5.7Generic error handling (174)5.7.1General (174)5.7.2ASN.1 violation or encoding error (174)5.7.3Field set to a not comprehended value (174)5.7.4Mandatory field missing (174)5.7.5Not comprehended field (176)5.8MBMS (176)5.8.1Introduction (176)5.8.1.1General (176)5.8.1.2Scheduling (176)5.8.1.3MCCH information validity and notification of changes (176)5.8.2MCCH information acquisition (178)5.8.2.1General (178)5.8.2.2Initiation (178)5.8.2.3MCCH information acquisition by the UE (178)5.8.2.4Actions upon reception of the MBSFNAreaConfiguration message (178)5.8.2.5Actions upon reception of the MBMSCountingRequest message (179)5.8.3MBMS PTM radio bearer configuration (179)5.8.3.1General (179)5.8.3.2Initiation (179)5.8.3.3MRB establishment (179)5.8.3.4MRB release (179)5.8.4MBMS Counting Procedure (179)5.8.4.1General (179)5.8.4.2Initiation (180)5.8.4.3Reception of the MBMSCountingRequest message by the UE (180)5.8.5MBMS interest indication (181)5.8.5.1General (181)5.8.5.2Initiation (181)5.8.5.3Determine MBMS frequencies of interest (182)5.8.5.4Actions related to transmission of MBMSInterestIndication message (183)5.8a SC-PTM (183)5.8a.1Introduction (183)5.8a.1.1General (183)5.8a.1.2SC-MCCH scheduling (183)5.8a.1.3SC-MCCH information validity and notification of changes (183)5.8a.1.4Procedures (184)5.8a.2SC-MCCH information acquisition (184)5.8a.2.1General (184)5.8a.2.2Initiation (184)5.8a.2.3SC-MCCH information acquisition by the UE (184)5.8a.2.4Actions upon reception of the SCPTMConfiguration message (185)5.8a.3SC-PTM radio bearer configuration (185)5.8a.3.1General (185)5.8a.3.2Initiation (185)5.8a.3.3SC-MRB establishment (185)5.8a.3.4SC-MRB release (185)5.9RN procedures (186)5.9.1RN reconfiguration (186)5.9.1.1General (186)5.9.1.2Initiation (186)5.9.1.3Reception of the RNReconfiguration by the RN (186)5.10Sidelink (186)5.10.1Introduction (186)5.10.1a Conditions for sidelink communication operation (187)5.10.2Sidelink UE information (188)5.10.2.1General (188)5.10.2.2Initiation (189)5.10.2.3Actions related to transmission of SidelinkUEInformation message (193)5.10.3Sidelink communication monitoring (195)5.10.6Sidelink discovery announcement (198)5.10.6a Sidelink discovery announcement pool selection (201)5.10.6b Sidelink discovery announcement reference carrier selection (201)5.10.7Sidelink synchronisation information transmission (202)5.10.7.1General (202)5.10.7.2Initiation (203)5.10.7.3Transmission of SLSS (204)5.10.7.4Transmission of MasterInformationBlock-SL message (205)5.10.7.5Void (206)5.10.8Sidelink synchronisation reference (206)5.10.8.1General (206)5.10.8.2Selection and reselection of synchronisation reference UE (SyncRef UE) (206)5.10.9Sidelink common control information (207)5.10.9.1General (207)5.10.9.2Actions related to reception of MasterInformationBlock-SL message (207)5.10.10Sidelink relay UE operation (207)5.10.10.1General (207)5.10.10.2AS-conditions for relay related sidelink communication transmission by sidelink relay UE (207)5.10.10.3AS-conditions for relay PS related sidelink discovery transmission by sidelink relay UE (208)5.10.10.4Sidelink relay UE threshold conditions (208)5.10.11Sidelink remote UE operation (208)5.10.11.1General (208)5.10.11.2AS-conditions for relay related sidelink communication transmission by sidelink remote UE (208)5.10.11.3AS-conditions for relay PS related sidelink discovery transmission by sidelink remote UE (209)5.10.11.4Selection and reselection of sidelink relay UE (209)5.10.11.5Sidelink remote UE threshold conditions (210)6Protocol data units, formats and parameters (tabular & ASN.1) (210)6.1General (210)6.2RRC messages (212)6.2.1General message structure (212)–EUTRA-RRC-Definitions (212)–BCCH-BCH-Message (212)–BCCH-DL-SCH-Message (212)–BCCH-DL-SCH-Message-BR (213)–MCCH-Message (213)–PCCH-Message (213)–DL-CCCH-Message (214)–DL-DCCH-Message (214)–UL-CCCH-Message (214)–UL-DCCH-Message (215)–SC-MCCH-Message (215)6.2.2Message definitions (216)–CounterCheck (216)–CounterCheckResponse (217)–CSFBParametersRequestCDMA2000 (217)–CSFBParametersResponseCDMA2000 (218)–DLInformationTransfer (218)–HandoverFromEUTRAPreparationRequest (CDMA2000) (219)–InDeviceCoexIndication (220)–InterFreqRSTDMeasurementIndication (222)–LoggedMeasurementConfiguration (223)–MasterInformationBlock (225)–MBMSCountingRequest (226)–MBMSCountingResponse (226)–MBMSInterestIndication (227)–MBSFNAreaConfiguration (228)–MeasurementReport (228)–MobilityFromEUTRACommand (229)–Paging (232)–ProximityIndication (233)–RNReconfiguration (234)–RNReconfigurationComplete (234)–RRCConnectionReconfiguration (235)–RRCConnectionReconfigurationComplete (240)–RRCConnectionReestablishment (241)–RRCConnectionReestablishmentComplete (241)–RRCConnectionReestablishmentReject (242)–RRCConnectionReestablishmentRequest (243)–RRCConnectionReject (243)–RRCConnectionRelease (244)–RRCConnectionResume (248)–RRCConnectionResumeComplete (249)–RRCConnectionResumeRequest (250)–RRCConnectionRequest (250)–RRCConnectionSetup (251)–RRCConnectionSetupComplete (252)–SCGFailureInformation (253)–SCPTMConfiguration (254)–SecurityModeCommand (255)–SecurityModeComplete (255)–SecurityModeFailure (256)–SidelinkUEInformation (256)–SystemInformation (258)–SystemInformationBlockType1 (259)–UEAssistanceInformation (264)–UECapabilityEnquiry (265)–UECapabilityInformation (266)–UEInformationRequest (267)–UEInformationResponse (267)–ULHandoverPreparationTransfer (CDMA2000) (273)–ULInformationTransfer (274)–WLANConnectionStatusReport (274)6.3RRC information elements (275)6.3.1System information blocks (275)–SystemInformationBlockType2 (275)–SystemInformationBlockType3 (279)–SystemInformationBlockType4 (282)–SystemInformationBlockType5 (283)–SystemInformationBlockType6 (287)–SystemInformationBlockType7 (289)–SystemInformationBlockType8 (290)–SystemInformationBlockType9 (295)–SystemInformationBlockType10 (295)–SystemInformationBlockType11 (296)–SystemInformationBlockType12 (297)–SystemInformationBlockType13 (297)–SystemInformationBlockType14 (298)–SystemInformationBlockType15 (298)–SystemInformationBlockType16 (299)–SystemInformationBlockType17 (300)–SystemInformationBlockType18 (301)–SystemInformationBlockType19 (301)–SystemInformationBlockType20 (304)6.3.2Radio resource control information elements (304)–AntennaInfo (304)–AntennaInfoUL (306)–CQI-ReportConfig (307)–CQI-ReportPeriodicProcExtId (314)–CrossCarrierSchedulingConfig (314)–CSI-IM-Config (315)–CSI-IM-ConfigId (315)–CSI-RS-Config (317)–CSI-RS-ConfigEMIMO (318)–CSI-RS-ConfigNZP (319)–CSI-RS-ConfigNZPId (320)–CSI-RS-ConfigZP (321)–CSI-RS-ConfigZPId (321)–DMRS-Config (321)–DRB-Identity (322)–EPDCCH-Config (322)–EIMTA-MainConfig (324)–LogicalChannelConfig (325)–LWA-Configuration (326)–LWIP-Configuration (326)–RCLWI-Configuration (327)–MAC-MainConfig (327)–P-C-AndCBSR (332)–PDCCH-ConfigSCell (333)–PDCP-Config (334)–PDSCH-Config (337)–PDSCH-RE-MappingQCL-ConfigId (339)–PHICH-Config (339)–PhysicalConfigDedicated (339)–P-Max (344)–PRACH-Config (344)–PresenceAntennaPort1 (346)–PUCCH-Config (347)–PUSCH-Config (351)–RACH-ConfigCommon (355)–RACH-ConfigDedicated (357)–RadioResourceConfigCommon (358)–RadioResourceConfigDedicated (362)–RLC-Config (367)–RLF-TimersAndConstants (369)–RN-SubframeConfig (370)–SchedulingRequestConfig (371)–SoundingRS-UL-Config (372)–SPS-Config (375)–TDD-Config (376)–TimeAlignmentTimer (377)–TPC-PDCCH-Config (377)–TunnelConfigLWIP (378)–UplinkPowerControl (379)–WLAN-Id-List (382)–WLAN-MobilityConfig (382)6.3.3Security control information elements (382)–NextHopChainingCount (382)–SecurityAlgorithmConfig (383)–ShortMAC-I (383)6.3.4Mobility control information elements (383)–AdditionalSpectrumEmission (383)–ARFCN-ValueCDMA2000 (383)–ARFCN-ValueEUTRA (384)–ARFCN-ValueGERAN (384)–ARFCN-ValueUTRA (384)–BandclassCDMA2000 (384)–BandIndicatorGERAN (385)–CarrierFreqCDMA2000 (385)–CarrierFreqGERAN (385)–CellIndexList (387)–CellReselectionPriority (387)–CellSelectionInfoCE (387)–CellReselectionSubPriority (388)–CSFB-RegistrationParam1XRTT (388)–CellGlobalIdEUTRA (389)–CellGlobalIdUTRA (389)–CellGlobalIdGERAN (390)–CellGlobalIdCDMA2000 (390)–CellSelectionInfoNFreq (391)–CSG-Identity (391)–FreqBandIndicator (391)–MobilityControlInfo (391)–MobilityParametersCDMA2000 (1xRTT) (393)–MobilityStateParameters (394)–MultiBandInfoList (394)–NS-PmaxList (394)–PhysCellId (395)–PhysCellIdRange (395)–PhysCellIdRangeUTRA-FDDList (395)–PhysCellIdCDMA2000 (396)–PhysCellIdGERAN (396)–PhysCellIdUTRA-FDD (396)–PhysCellIdUTRA-TDD (396)–PLMN-Identity (397)–PLMN-IdentityList3 (397)–PreRegistrationInfoHRPD (397)–Q-QualMin (398)–Q-RxLevMin (398)–Q-OffsetRange (398)–Q-OffsetRangeInterRAT (399)–ReselectionThreshold (399)–ReselectionThresholdQ (399)–SCellIndex (399)–ServCellIndex (400)–SpeedStateScaleFactors (400)–SystemInfoListGERAN (400)–SystemTimeInfoCDMA2000 (401)–TrackingAreaCode (401)–T-Reselection (402)–T-ReselectionEUTRA-CE (402)6.3.5Measurement information elements (402)–AllowedMeasBandwidth (402)–CSI-RSRP-Range (402)–Hysteresis (402)–LocationInfo (403)–MBSFN-RSRQ-Range (403)–MeasConfig (404)–MeasDS-Config (405)–MeasGapConfig (406)–MeasId (407)–MeasIdToAddModList (407)–MeasObjectCDMA2000 (408)–MeasObjectEUTRA (408)–MeasObjectGERAN (412)–MeasObjectId (412)–MeasObjectToAddModList (412)–MeasObjectUTRA (413)–ReportConfigEUTRA (422)–ReportConfigId (425)–ReportConfigInterRAT (425)–ReportConfigToAddModList (428)–ReportInterval (429)–RSRP-Range (429)–RSRQ-Range (430)–RSRQ-Type (430)–RS-SINR-Range (430)–RSSI-Range-r13 (431)–TimeToTrigger (431)–UL-DelayConfig (431)–WLAN-CarrierInfo (431)–WLAN-RSSI-Range (432)–WLAN-Status (432)6.3.6Other information elements (433)–AbsoluteTimeInfo (433)–AreaConfiguration (433)–C-RNTI (433)–DedicatedInfoCDMA2000 (434)–DedicatedInfoNAS (434)–FilterCoefficient (434)–LoggingDuration (434)–LoggingInterval (435)–MeasSubframePattern (435)–MMEC (435)–NeighCellConfig (435)–OtherConfig (436)–RAND-CDMA2000 (1xRTT) (437)–RAT-Type (437)–ResumeIdentity (437)–RRC-TransactionIdentifier (438)–S-TMSI (438)–TraceReference (438)–UE-CapabilityRAT-ContainerList (438)–UE-EUTRA-Capability (439)–UE-RadioPagingInfo (469)–UE-TimersAndConstants (469)–VisitedCellInfoList (470)–WLAN-OffloadConfig (470)6.3.7MBMS information elements (472)–MBMS-NotificationConfig (472)–MBMS-ServiceList (473)–MBSFN-AreaId (473)–MBSFN-AreaInfoList (473)–MBSFN-SubframeConfig (474)–PMCH-InfoList (475)6.3.7a SC-PTM information elements (476)–SC-MTCH-InfoList (476)–SCPTM-NeighbourCellList (478)6.3.8Sidelink information elements (478)–SL-CommConfig (478)–SL-CommResourcePool (479)–SL-CP-Len (480)–SL-DiscConfig (481)–SL-DiscResourcePool (483)–SL-DiscTxPowerInfo (485)–SL-GapConfig (485)。
Rubiks Cube,a fascinating puzzle that has captivated millions of people around the world,is not just a toy but also a challenge that tests ones intelligence and patience.The cube,invented by ErnőRubik,a Hungarian architect,in1974,has since become a popular pastime and even a competitive sport.The Rubiks Cube is a3D combination puzzle consisting of six faces,each covered by nine stickers,with each face displaying a single color.The objective is to scramble the colors and then return each face to a single color by rotating the individual faces.It may sound simple,but the complexity lies in the fact that each move affects the positions of the other pieces,making it a challenging task to solve.Solving the Rubiks Cube requires a combination of logical thinking,spatial awareness, and sometimes even memorization.Many people approach the puzzle by learning algorithms,which are sequences of moves that solve a specific part of the cube.For beginners,the layerbylayer method is a common approach,where one solves the cube in stages,starting with the first layer and building up to the final configuration.The process of solving the Rubiks Cube can be broken down into several steps:1.Understanding the Cube:Before attempting to solve the cube,its essential to understand its structure and how each move affects the overall configuration.2.Solving the First Layer:This involves positioning the center pieces and then solving the edges to match with the center colors.3.Solving the Second Layer:After the first layer is complete,the next step is to solve the second layer without disrupting the first layer.4.Solving the Last Layer:This is often the most complex part,involving various algorithms to orient and permute the last layers pieces correctly.5.Practice and Mastery:With practice,solvers can memorize algorithms and improve their speed,aiming to solve the cube in the shortest time possible.The Rubiks Cube has also become a competitive activity,with speedcubers aiming to solve the cube as quickly as possible.World Cube Association WCA organizes competitions where participants are timed and ranked based on their performance.Moreover,the cube has inspired various versions and modifications,such as the2x2,4x4, 5x5,and even larger cubes,each offering its own unique set of challenges.In conclusion,the Rubiks Cube is more than just a puzzle its a testament to human ingenuity and the joy of overcoming challenges.Whether youre solving it for fun or aiming to compete,the Rubiks Cube offers a rewarding experience that sharpens the mind and provides a sense of accomplishment.。
Glider Flying Handbook2013U.S. Department of TransportationFEDERAL AVIATION ADMINISTRATIONFlight Standards Servicei iPrefaceThe Glider Flying Handbook is designed as a technical manual for applicants who are preparing for glider category rating and for currently certificated glider pilots who wish to improve their knowledge. Certificated flight instructors will find this handbook a valuable training aid, since detailed coverage of aeronautical decision-making, components and systems, aerodynamics, flight instruments, performance limitations, ground operations, flight maneuvers, traffic patterns, emergencies, soaring weather, soaring techniques, and cross-country flight is included. Topics such as radio navigation and communication, use of flight information publications, and regulations are available in other Federal Aviation Administration (FAA) publications.The discussion and explanations reflect the most commonly used practices and principles. Occasionally, the word “must” or similar language is used where the desired action is deemed critical. The use of such language is not intended to add to, interpret, or relieve a duty imposed by Title 14 of the Code of Federal Regulations (14 CFR). Persons working towards a glider rating are advised to review the references from the applicable practical test standards (FAA-G-8082-4, Sport Pilot and Flight Instructor with a Sport Pilot Rating Knowledge Test Guide, FAA-G-8082-5, Commercial Pilot Knowledge Test Guide, and FAA-G-8082-17, Recreational Pilot and Private Pilot Knowledge Test Guide). Resources for study include FAA-H-8083-25, Pilot’s Handbook of Aeronautical Knowledge, FAA-H-8083-2, Risk Management Handbook, and Advisory Circular (AC) 00-6, Aviation Weather For Pilots and Flight Operations Personnel, AC 00-45, Aviation Weather Services, as these documents contain basic material not duplicated herein. All beginning applicants should refer to FAA-H-8083-25, Pilot’s Handbook of Aeronautical Knowledge, for study and basic library reference.It is essential for persons using this handbook to become familiar with and apply the pertinent parts of 14 CFR and the Aeronautical Information Manual (AIM). The AIM is available online at . The current Flight Standards Service airman training and testing material and learning statements for all airman certificates and ratings can be obtained from .This handbook supersedes FAA-H-8083-13, Glider Flying Handbook, dated 2003. Always select the latest edition of any publication and check the website for errata pages and listing of changes to FAA educational publications developed by the FAA’s Airman Testing Standards Branch, AFS-630.This handbook is available for download, in PDF format, from .This handbook is published by the United States Department of Transportation, Federal Aviation Administration, Airman Testing Standards Branch, AFS-630, P.O. Box 25082, Oklahoma City, OK 73125.Comments regarding this publication should be sent, in email form, to the following address:********************************************John M. AllenDirector, Flight Standards Serviceiiii vAcknowledgmentsThe Glider Flying Handbook was produced by the Federal Aviation Administration (FAA) with the assistance of Safety Research Corporation of America (SRCA). The FAA wishes to acknowledge the following contributors: Sue Telford of Telford Fishing & Hunting Services for images used in Chapter 1JerryZieba () for images used in Chapter 2Tim Mara () for images used in Chapters 2 and 12Uli Kremer of Alexander Schleicher GmbH & Co for images used in Chapter 2Richard Lancaster () for images and content used in Chapter 3Dave Nadler of Nadler & Associates for images used in Chapter 6Dave McConeghey for images used in Chapter 6John Brandon (www.raa.asn.au) for images and content used in Chapter 7Patrick Panzera () for images used in Chapter 8Jeff Haby (www.theweatherprediction) for images used in Chapter 8National Soaring Museum () for content used in Chapter 9Bill Elliot () for images used in Chapter 12.Tiffany Fidler for images used in Chapter 12.Additional appreciation is extended to the Soaring Society of America, Inc. (), the Soaring Safety Foundation, and Mr. Brad Temeyer and Mr. Bill Martin from the National Oceanic and Atmospheric Administration (NOAA) for their technical support and input.vv iPreface (iii)Acknowledgments (v)Table of Contents (vii)Chapter 1Gliders and Sailplanes ........................................1-1 Introduction....................................................................1-1 Gliders—The Early Years ..............................................1-2 Glider or Sailplane? .......................................................1-3 Glider Pilot Schools ......................................................1-4 14 CFR Part 141 Pilot Schools ...................................1-5 14 CFR Part 61 Instruction ........................................1-5 Glider Certificate Eligibility Requirements ...................1-5 Common Glider Concepts ..............................................1-6 Terminology...............................................................1-6 Converting Metric Distance to Feet ...........................1-6 Chapter 2Components and Systems .................................2-1 Introduction....................................................................2-1 Glider Design .................................................................2-2 The Fuselage ..................................................................2-4 Wings and Components .............................................2-4 Lift/Drag Devices ...........................................................2-5 Empennage .....................................................................2-6 Towhook Devices .......................................................2-7 Powerplant .....................................................................2-7 Self-Launching Gliders .............................................2-7 Sustainer Engines .......................................................2-8 Landing Gear .................................................................2-8 Wheel Brakes .............................................................2-8 Chapter 3Aerodynamics of Flight .......................................3-1 Introduction....................................................................3-1 Forces of Flight..............................................................3-2 Newton’s Third Law of Motion .................................3-2 Lift ..............................................................................3-2The Effects of Drag on a Glider .....................................3-3 Parasite Drag ..............................................................3-3 Form Drag ...............................................................3-3 Skin Friction Drag ..................................................3-3 Interference Drag ....................................................3-5 Total Drag...................................................................3-6 Wing Planform ...........................................................3-6 Elliptical Wing ........................................................3-6 Rectangular Wing ...................................................3-7 Tapered Wing .........................................................3-7 Swept-Forward Wing ..............................................3-7 Washout ..................................................................3-7 Glide Ratio .................................................................3-8 Aspect Ratio ............................................................3-9 Weight ........................................................................3-9 Thrust .........................................................................3-9 Three Axes of Rotation ..................................................3-9 Stability ........................................................................3-10 Flutter .......................................................................3-11 Lateral Stability ........................................................3-12 Turning Flight ..............................................................3-13 Load Factors .................................................................3-13 Radius of Turn ..........................................................3-14 Turn Coordination ....................................................3-15 Slips ..........................................................................3-15 Forward Slip .........................................................3-16 Sideslip .................................................................3-17 Spins .........................................................................3-17 Ground Effect ...............................................................3-19 Chapter 4Flight Instruments ...............................................4-1 Introduction....................................................................4-1 Pitot-Static Instruments ..................................................4-2 Impact and Static Pressure Lines................................4-2 Airspeed Indicator ......................................................4-2 The Effects of Altitude on the AirspeedIndicator..................................................................4-3 Types of Airspeed ...................................................4-3Table of ContentsviiAirspeed Indicator Markings ......................................4-5 Other Airspeed Limitations ........................................4-6 Altimeter .....................................................................4-6 Principles of Operation ...........................................4-6 Effect of Nonstandard Pressure andTemperature............................................................4-7 Setting the Altimeter (Kollsman Window) .............4-9 Types of Altitude ......................................................4-10 Variometer................................................................4-11 Total Energy System .............................................4-14 Netto .....................................................................4-14 Electronic Flight Computers ....................................4-15 Magnetic Compass .......................................................4-16 Yaw String ................................................................4-16 Inclinometer..............................................................4-16 Gyroscopic Instruments ...............................................4-17 G-Meter ........................................................................4-17 FLARM Collision Avoidance System .........................4-18 Chapter 5Glider Performance .............................................5-1 Introduction....................................................................5-1 Factors Affecting Performance ......................................5-2 High and Low Density Altitude Conditions ...........5-2 Atmospheric Pressure .............................................5-2 Altitude ...................................................................5-3 Temperature............................................................5-3 Wind ...........................................................................5-3 Weight ........................................................................5-5 Rate of Climb .................................................................5-7 Flight Manuals and Placards ..........................................5-8 Placards ......................................................................5-8 Performance Information ...........................................5-8 Glider Polars ...............................................................5-8 Weight and Balance Information .............................5-10 Limitations ...............................................................5-10 Weight and Balance .....................................................5-12 Center of Gravity ......................................................5-12 Problems Associated With CG Forward ofForward Limit .......................................................5-12 Problems Associated With CG Aft of Aft Limit ..5-13 Sample Weight and Balance Problems ....................5-13 Ballast ..........................................................................5-14 Chapter 6Preflight and Ground Operations .......................6-1 Introduction....................................................................6-1 Assembly and Storage Techniques ................................6-2 Trailering....................................................................6-3 Tiedown and Securing ................................................6-4Water Ballast ..............................................................6-4 Ground Handling........................................................6-4 Launch Equipment Inspection ....................................6-5 Glider Preflight Inspection .........................................6-6 Prelaunch Checklist ....................................................6-7 Glider Care .....................................................................6-7 Preventive Maintenance .............................................6-8 Chapter 7Launch and Recovery Procedures and Flight Maneuvers ............................................................7-1 Introduction....................................................................7-1 Aerotow Takeoff Procedures .........................................7-2 Signals ........................................................................7-2 Prelaunch Signals ....................................................7-2 Inflight Signals ........................................................7-3 Takeoff Procedures and Techniques ..........................7-3 Normal Assisted Takeoff............................................7-4 Unassisted Takeoff.....................................................7-5 Crosswind Takeoff .....................................................7-5 Assisted ...................................................................7-5 Unassisted...............................................................7-6 Aerotow Climb-Out ....................................................7-6 Aerotow Release.........................................................7-8 Slack Line ...................................................................7-9 Boxing the Wake ......................................................7-10 Ground Launch Takeoff Procedures ............................7-11 CG Hooks .................................................................7-11 Signals ......................................................................7-11 Prelaunch Signals (Winch/Automobile) ...............7-11 Inflight Signals ......................................................7-12 Tow Speeds ..............................................................7-12 Automobile Launch ..................................................7-14 Crosswind Takeoff and Climb .................................7-14 Normal Into-the-Wind Launch .................................7-15 Climb-Out and Release Procedures ..........................7-16 Self-Launch Takeoff Procedures ..............................7-17 Preparation and Engine Start ....................................7-17 Taxiing .....................................................................7-18 Pretakeoff Check ......................................................7-18 Normal Takeoff ........................................................7-19 Crosswind Takeoff ...................................................7-19 Climb-Out and Shutdown Procedures ......................7-19 Landing .....................................................................7-21 Gliderport/Airport Traffic Patterns and Operations .....7-22 Normal Approach and Landing ................................7-22 Crosswind Landing ..................................................7-25 Slips ..........................................................................7-25 Downwind Landing ..................................................7-27 After Landing and Securing .....................................7-27viiiPerformance Maneuvers ..............................................7-27 Straight Glides ..........................................................7-27 Turns.........................................................................7-28 Roll-In ...................................................................7-29 Roll-Out ................................................................7-30 Steep Turns ...........................................................7-31 Maneuvering at Minimum Controllable Airspeed ...7-31 Stall Recognition and Recovery ...............................7-32 Secondary Stalls ....................................................7-34 Accelerated Stalls .................................................7-34 Crossed-Control Stalls ..........................................7-35 Operating Airspeeds .....................................................7-36 Minimum Sink Airspeed ..........................................7-36 Best Glide Airspeed..................................................7-37 Speed to Fly ..............................................................7-37 Chapter 8Abnormal and Emergency Procedures .............8-1 Introduction....................................................................8-1 Porpoising ......................................................................8-2 Pilot-Induced Oscillations (PIOs) ..............................8-2 PIOs During Launch ...................................................8-2 Factors Influencing PIOs ........................................8-2 Improper Elevator Trim Setting ..............................8-3 Improper Wing Flaps Setting ..................................8-3 Pilot-Induced Roll Oscillations During Launch .........8-3 Pilot-Induced Yaw Oscillations During Launch ........8-4 Gust-Induced Oscillations ..............................................8-5 Vertical Gusts During High-Speed Cruise .................8-5 Pilot-Induced Pitch Oscillations During Landing ......8-6 Glider-Induced Oscillations ...........................................8-6 Pitch Influence of the Glider Towhook Position ........8-6 Self-Launching Glider Oscillations During Powered Flight ...........................................................8-7 Nosewheel Glider Oscillations During Launchesand Landings ..............................................................8-7 Tailwheel/Tailskid Equipped Glider Oscillations During Launches and Landings ..................................8-8 Aerotow Abnormal and Emergency Procedures ............8-8 Abnormal Procedures .................................................8-8 Towing Failures........................................................8-10 Tow Failure With Runway To Land and Stop ......8-11 Tow Failure Without Runway To Land BelowReturning Altitude ................................................8-11 Tow Failure Above Return to Runway Altitude ...8-11 Tow Failure Above 800' AGL ..............................8-12 Tow Failure Above Traffic Pattern Altitude .........8-13 Slack Line .................................................................8-13 Ground Launch Abnormal and Emergency Procedures ....................................................................8-14 Abnormal Procedures ...............................................8-14 Emergency Procedures .............................................8-14 Self-Launch Takeoff Emergency Procedures ..............8-15 Emergency Procedures .............................................8-15 Spiral Dives ..................................................................8-15 Spins .............................................................................8-15 Entry Phase ...............................................................8-17 Incipient Phase .........................................................8-17 Developed Phase ......................................................8-17 Recovery Phase ........................................................8-17 Off-Field Landing Procedures .....................................8-18 Afterlanding Off Field .............................................8-20 Off-Field Landing Without Injury ........................8-20 Off-Field Landing With Injury .............................8-20 System and Equipment Malfunctions ..........................8-20 Flight Instrument Malfunctions ................................8-20 Airspeed Indicator Malfunctions ..........................8-21 Altimeter Malfunctions .........................................8-21 Variometer Malfunctions ......................................8-21 Compass Malfunctions .........................................8-21 Glider Canopy Malfunctions ....................................8-21 Broken Glider Canopy ..........................................8-22 Frosted Glider Canopy ..........................................8-22 Water Ballast Malfunctions ......................................8-22 Retractable Landing Gear Malfunctions ..................8-22 Primary Flight Control Systems ...............................8-22 Elevator Malfunctions ..........................................8-22 Aileron Malfunctions ............................................8-23 Rudder Malfunctions ............................................8-24 Secondary Flight Controls Systems .........................8-24 Elevator Trim Malfunctions .................................8-24 Spoiler/Dive Brake Malfunctions .........................8-24 Miscellaneous Flight System Malfunctions .................8-25 Towhook Malfunctions ............................................8-25 Oxygen System Malfunctions ..................................8-25 Drogue Chute Malfunctions .....................................8-25 Self-Launching Gliders ................................................8-26 Self-Launching/Sustainer Glider Engine Failure During Takeoff or Climb ..........................................8-26 Inability to Restart a Self-Launching/SustainerGlider Engine While Airborne .................................8-27 Self-Launching Glider Propeller Malfunctions ........8-27 Self-Launching Glider Electrical System Malfunctions .............................................................8-27 In-flight Fire .............................................................8-28 Emergency Equipment and Survival Gear ...................8-28 Survival Gear Checklists ..........................................8-28 Food and Water ........................................................8-28ixClothing ....................................................................8-28 Communication ........................................................8-29 Navigation Equipment ..............................................8-29 Medical Equipment ..................................................8-29 Stowage ....................................................................8-30 Parachute ..................................................................8-30 Oxygen System Malfunctions ..................................8-30 Accident Prevention .....................................................8-30 Chapter 9Soaring Weather ..................................................9-1 Introduction....................................................................9-1 The Atmosphere .............................................................9-2 Composition ...............................................................9-2 Properties ....................................................................9-2 Temperature............................................................9-2 Density ....................................................................9-2 Pressure ...................................................................9-2 Standard Atmosphere .................................................9-3 Layers of the Atmosphere ..........................................9-4 Scale of Weather Events ................................................9-4 Thermal Soaring Weather ..............................................9-6 Thermal Shape and Structure .....................................9-6 Atmospheric Stability .................................................9-7 Air Masses Conducive to Thermal Soaring ...................9-9 Cloud Streets ..............................................................9-9 Thermal Waves...........................................................9-9 Thunderstorms..........................................................9-10 Lifted Index ..........................................................9-12 K-Index .................................................................9-12 Weather for Slope Soaring .......................................9-14 Mechanism for Wave Formation ..............................9-16 Lift Due to Convergence ..........................................9-19 Obtaining Weather Information ...................................9-21 Preflight Weather Briefing........................................9-21 Weather-ReIated Information ..................................9-21 Interpreting Weather Charts, Reports, andForecasts ......................................................................9-23 Graphic Weather Charts ...........................................9-23 Winds and Temperatures Aloft Forecast ..............9-23 Composite Moisture Stability Chart .....................9-24 Chapter 10Soaring Techniques ..........................................10-1 Introduction..................................................................10-1 Thermal Soaring ...........................................................10-2 Locating Thermals ....................................................10-2 Cumulus Clouds ...................................................10-2 Other Indicators of Thermals ................................10-3 Wind .....................................................................10-4 The Big Picture .....................................................10-5Entering a Thermal ..............................................10-5 Inside a Thermal.......................................................10-6 Bank Angle ...........................................................10-6 Speed .....................................................................10-6 Centering ...............................................................10-7 Collision Avoidance ................................................10-9 Exiting a Thermal .....................................................10-9 Atypical Thermals ..................................................10-10 Ridge/Slope Soaring ..................................................10-10 Traps ......................................................................10-10 Procedures for Safe Flying .....................................10-12 Bowls and Spurs .....................................................10-13 Slope Lift ................................................................10-13 Obstructions ...........................................................10-14 Tips and Techniques ...............................................10-15 Wave Soaring .............................................................10-16 Preflight Preparation ...............................................10-17 Getting Into the Wave ............................................10-18 Flying in the Wave .................................................10-20 Soaring Convergence Zones ...................................10-23 Combined Sources of Updrafts ..............................10-24 Chapter 11Cross-Country Soaring .....................................11-1 Introduction..................................................................11-1 Flight Preparation and Planning ...................................11-2 Personal and Special Equipment ..................................11-3 Navigation ....................................................................11-5 Using the Plotter .......................................................11-5 A Sample Cross-Country Flight ...............................11-5 Navigation Using GPS .............................................11-8 Cross-Country Techniques ...........................................11-9 Soaring Faster and Farther .........................................11-11 Height Bands ..........................................................11-11 Tips and Techniques ...............................................11-12 Special Situations .......................................................11-14 Course Deviations ..................................................11-14 Lost Procedures ......................................................11-14 Cross-Country Flight in a Self-Launching Glider .....11-15 High-Performance Glider Operations and Considerations ............................................................11-16 Glider Complexity ..................................................11-16 Water Ballast ..........................................................11-17 Cross-Country Flight Using Other Lift Sources ........11-17 Chapter 12Towing ................................................................12-1 Introduction..................................................................12-1 Equipment Inspections and Operational Checks .........12-2 Tow Hook ................................................................12-2 Schweizer Tow Hook ...........................................12-2x。
商务英语文本范文1Business English texts play a crucial role in the professional world. Let's take a look at the common formats and norms of some typical ones. For instance, in a business email, the subject line should be concise and specific, like "Urgent: Meeting Rescheduling Request". The salutation should be polite and appropriate, such as "Dear Mr. Smith" or "Dear Ms. Johnson". The body of the email must be clear and to the point. It could start with a brief introduction and then explain the main purpose. For example, "I am writing to inform you that..." The conclusion should be polite and express gratitude or expectations. Something like "Thank you for your attention. Looking forward to your reply soon."When it comes to a business report, the table of contents helps readers navigate easily. The abstract provides a summary of the key points. The main body presents detailed information and analysis. And the conclusion summarizes the main findings and offers recommendations. For example, in the conclusion, one might say, "Based on the above analysis, it is recommended that we take the following actions..."Oh, how important it is to follow these formats and norms correctly in business communication! Can you imagine the chaos if we ignored them? So, always pay attention and master these rules to ensure effective andprofessional communication!2In the world of business, the language we use is crucial! It's not just about communicating; it's about making precise, impactful, and strategic statements. Take, for instance, the realm of business negotiations. Phrases like "win-win situation", "best offer", and "bottom line" are frequently employed. When you say, "We're aiming for a win-win situation in this deal", it implies a mutual benefit and a cooperative spirit. Or when you state, "This is our best offer, take it or leave it", it shows a certain determination and confidence.In marketing, terms such as "brand awareness", "target audience", and "market penetration" are indispensable. "We need to increase our brand awareness to attract more of the target audience" clearly conveys the marketing objective. And in human resource management, "performance appraisal", "employee engagement", and "talent acquisition" are common. Saying, "The performance appraisal system needs to be revamped for better employee engagement" highlights the importance of these aspects.The use of these specific vocabularies and phrases in different business scenarios gives clarity, precision, and professionalism to our communication. Isn't it amazing how a few words can shape and drive business decisions? So, let's master this language and excel in the business world!Business English texts play a crucial role in the world of commerce. They are characterized by a distinct language style that is严谨, objective, and polite. For instance, when making a request in a business text, one might say, "We would highly appreciate it if you could kindly provide the necessary information by the end of this week." This statement is polite and direct.Now, consider a situation where a refusal is needed. It could be expressed as, "Unfortunately, due to the current circumstances and limited resources, we are unable to fulfill your request at this time. However, we will keep your inquiry on record and notify you if there are any changes in the future." Such a response is both clear and respectful.When it comes to giving suggestions, a common way is, "It might be beneficial for us to explore alternative solutions such as implementing a new marketing strategy or expanding our product range. What do you think about these proposals?" This shows a collaborative and consultative approach.In conclusion, the language style of business English texts is essential for effective communication and building successful business relationships. Don't you agree?Business English texts play a crucial role in the world of commerce. They are the means by which companies communicate their ideas, plans, and proposals. Let's take a look at some excellent examples to understand how to convey business information clearly and effectively.In a well-structured business English text, the key points are always highlighted. For instance, important dates, figures, or key terms are often presented in bold or italic to draw attention. The paragraphs are organized logically, with each one focusing on a specific aspect of the topic. This helps the reader follow the flow of information smoothly.When it comes to using charts and graphs, they can be extremely powerful tools! They present complex data in a visually appealing and easy-to-understand way. For example, a sales report might include a bar chart to show the monthly sales trends. Isn't that much more intuitive than just listing numbers?However, it's not just about presenting information. The language used must be precise and professional. Avoid ambiguous words and phrases. Use active voice to make the text more direct and engaging.In conclusion, a successful business English text combines clear organization, visual aids, and precise language. This enables businesses to communicate effectively and achieve their goals. How important and amazing is that?In today's globalized business world, the significance of business English texts in cross-cultural communication simply cannot be overstated! How crucial is it? Well, imagine you're dealing with a business partner from Japan and using direct, assertive language that might be well-received in the West. But in Japanese culture, where politeness and indirectness are highly valued, this approach could lead to misunderstandings and even potential breakdowns in communication.When communicating with partners from countries like Germany, precision and clarity are paramount. Long, convoluted sentences might confuse them, as they prefer straightforward and concise messaging. However, in countries like France, a more elaborate and artistic style of expression might be appreciated.For instance, when writing to a potential client in China, it's essential to incorporate elements of respect and formality. Using honorifics and expressing gratitude in a traditional way can go a long way in establishing a positive rapport.So, it's crystal clear that understanding and adapting the content and expression of business English texts based on cultural differences is not just important – it's absolutely essential for successful cross-cultural business interactions! How can we afford to overlook such a vital aspect in our globalized marketplace?。
利用径向速度的Kalman-PDA滤波算法刘代;赵永波;高剑;李伟【摘要】提出了一种利用径向速度的Kalman-PDA滤波算法(定义为KalmanV-PDA),在数据关联法(probabilistic data association,PDA)算法和Kalman滤波算法结合使用时,利用径向速度建立速度波门,推导了速度波门表达式,在量测方程中引入径向速度维,利用动目标检测(moving targets detection,MTD)测出的径向速度实时更新目标观测值中的径向速度,仿真表明,该算法相比标准的Kalman-PDA滤波算法提高了目标预测精度,改善了目标跟踪性能,而且MTD测速误差对跟踪性能影响较小.【期刊名称】《系统工程与电子技术》【年(卷),期】2018(040)010【总页数】5页(P2195-2199)【关键词】径向速度;KalmanV-PDA;速度波门;动目标检测【作者】刘代;赵永波;高剑;李伟【作者单位】西安电子科技大学雷达信号处理国家重点实验室,陕西西安710071;西安电子工程研究所,陕西西安710100;西安电子科技大学雷达信号处理国家重点实验室,陕西西安710071;西安电子工程研究所,陕西西安710100;西安电子工程研究所,陕西西安710100【正文语种】中文【中图分类】TN9530 引言在雷达数据处理中,将概率数据关联法(probabilistic data association, PDA)算法和Kalman滤波算法相结合使用越来越广泛[1-5]。
PDA算法能在跟踪波门内对多个过门限的量测数据进行数据关联,确定各个量测来源于目标的概率,并利用其对新息加权获得目标的状态估计。
在雷达目标跟踪中,Kalman滤波算法是最小方差意义下的最优算法[6]。
将PDA算法与Kalman算法结合使用很好地得到目标的状态估计并使目标的最小方差最优。
文献[1-5]将PDA算法和Kalman滤波算法相结合应用到MUSIC信号处理、码分多址(code division multiple access, CDMA)通信和多输入多输出(multiple-input multiple-output, MIMO)信道,得到很好的滤波效果。
第五版电镀锌fmea范文英文回答：FMEA (Failure Mode and Effects Analysis) is asystematic approach used to identify and analyze potential failures in a process, product, or system. It helps to identify and prioritize potential failures based on their severity, occurrence, and detectability, and then take proactive measures to prevent or mitigate these failures.As an engineer, I have had the opportunity to work on the fifth edition of the FMEA for the process of electroplating with zinc. This process involves coating a metal object with a layer of zinc to provide corrosion resistance and improve its appearance. In order to conduct an effective FMEA, I followed a step-by-step approach.Firstly, I gathered a cross-functional team consistingof experts from various departments involved in the electroplating process, such as production, quality control,and maintenance. This ensured that all perspectives and potential failure modes were considered during the analysis.Next, we identified the potential failure modes that could occur during the electroplating process. For example, one potential failure mode could be inadequate cleaning of the metal surface before electroplating, leading to poor adhesion of the zinc layer. This failure mode could resultin the zinc layer peeling off, compromising the corrosion resistance of the coated object.After identifying the failure modes, we assessed their severity, occurrence, and detectability. Severity refers to the impact of the failure on the product or process, occurrence refers to the likelihood of the failure happening, and detectability refers to the ability todetect the failure before it reaches the customer. We useda scale of 1 to 10 to rate each factor, with 10 being the highest.Based on these ratings, we calculated the Risk Priority Number (RPN) for each failure mode by multiplying theseverity, occurrence, and detectability ratings. This helped us prioritize the failure modes and focus on those with the highest RPNs. For example, if we identified a failure mode with a high severity rating, high occurrence rating, and low detectability rating, it would have a high RPN and would require immediate attention.Once we had identified and prioritized the failure modes, we brainstormed potential actions to prevent or mitigate these failures. For example, to address the inadequate cleaning failure mode, we implemented achecklist to ensure that the metal surface is properly cleaned before electroplating. This simple action helped to reduce the occurrence of poor adhesion and improved the overall quality of the zinc coating.After implementing the preventive actions, we monitored the process and conducted regular audits to ensure their effectiveness. We also updated the FMEA documentation to reflect any changes made to the process or actions taken to address the failure modes.Overall, the FMEA process for the electroplating with zinc in the fifth edition was a valuable tool inidentifying and addressing potential failures. It helped us to take proactive measures to prevent or mitigate these failures and improve the overall quality of theelectroplated products.中文回答：FMEA（故障模式与影响分析）是一种系统性的方法，用于识别和分析过程、产品或系统中潜在的故障。
基于变分信息瓶颈的半监督神经机器翻译于志强1, 2, 3余正涛 1, 3 黄于欣 1, 3 郭军军 1, 3 高盛祥1, 3摘 要 变分方法是机器翻译领域的有效方法, 其性能较依赖于数据量规模. 然而在低资源环境下, 平行语料资源匮乏,不能满足变分方法对数据量的需求, 因此导致基于变分的模型翻译效果并不理想. 针对该问题, 本文提出基于变分信息瓶颈的半监督神经机器翻译方法, 所提方法的具体思路为: 首先在小规模平行语料的基础上, 通过引入跨层注意力机制充分利用神经网络各层特征信息, 训练得到基础翻译模型; 随后, 利用基础翻译模型, 使用回译方法从单语语料生成含噪声的大规模伪平行语料, 对两种平行语料进行合并形成组合语料, 使其在规模上能够满足变分方法对数据量的需求; 最后, 为了减少组合语料中的噪声, 利用变分信息瓶颈方法在源与目标之间添加中间表征, 通过训练使该表征具有放行重要信息、阻止非重要信息流过的能力, 从而达到去除噪声的效果. 多个数据集上的实验结果表明, 本文所提方法能够显著地提高译文质量, 是一种适用于低资源场景的半监督神经机器翻译方法.关键词 神经机器翻译, 跨层注意力机制, 回译, 变分信息瓶颈引用格式 于志强, 余正涛, 黄于欣, 郭军军, 高盛祥. 基于变分信息瓶颈的半监督神经机器翻译. 自动化学报, 2022, 48(7):1678−1689DOI 10.16383/j.aas.c190477Improving Semi-supervised Neural Machine Translation WithVariational Information BottleneckYU Zhi-Qiang 1, 2, 3 YU Zheng-Tao 1, 3 HUANG Yu-Xin 1, 3 GUO Jun-Jun 1, 3 GAO Sheng-Xiang 1, 3Abstract Variational approach is effective in the field of machine translation, its performance is highly dependent on the scale of the data. However, in low-resource setting, parallel corpus is limited, which cannot meet the de-mand of variational approach on data, resulting in suboptimal translation effect. To address this problem, we pro-pose a semi-supervised neural machine translation approach based on variational information bottleneck. The cent-ral ideas are as follows: 1) cross-layer attention mechanism is introduced to train the basic translation model;2) the trained basic translation model is used on the basis of small-scale parallel corpus, then get large-scale noisy pseudo-parallel corpus by back-translation with the input of monolingual corpus. Finally, pseudo-parallel and paral-lel corpora are merged into combinatorial corpora; 3) variational information bottleneck is used to reduce data noise and eliminate information redundancy in the combinatorial corpus. Experiment results on multiple language pairs show that the model we proposed can effectively improve the quality of translation.Key words Neural machine translation, cross-layer attention mechanism, back-translation, variational information bottleneckCitation Yu Zhi-Qiang, Yu Zheng-Tao, Huang Yu-Xin, Guo Jun-Jun, Gao Sheng-Xiang. Improving semi-super-vised neural machine translation with variational information bottleneck. Acta Automatica Sinica , 2022, 48(7):1678−1689自端到端的神经机器翻译(Neural machine translation)模型[1−2]提出以来, 神经机器翻译得到了飞速的发展. 基于注意力机制[2]的神经机器翻译模型提出之后, 更使得神经机器翻译在很多语言对上的翻译性能超越了传统的统计机器翻译(Statist-ical machine translation)[3], 成为自然语言处理领域的热点研究方向[4], 也因此促进了很多神经网络方法在其上的迁移与应用, 变分方法[5−6]即是其中一种重要方法. 变分方法已证明能够显著提升神经机器翻译的性能[7], 但是由于数据驱动特性, 其性能较收稿日期 2019-06-24 录用日期 2020-01-17Manuscript received June 24, 2019; accepted January 17, 2020国家重点研发计划(2019QY1800), 国家自然科学基金(61732005, 61672271, 61761026, 61762056, 61866020), 云南省高新技术产业专项基金(201606), 云南省自然科学基金(2018FB104)资助Supported by National Key Research and Development Pro-gram of China (2019QY1800), National Natural Science Founda-tion of China (61732005, 61672271, 61761026, 61762056, 61866020), Yunnan High-Tech Industry Development Project (201606), and Natural Science Foundation of Yunnan Province (2018FB104)本文责任编委 张民Recommended by Associate Editor ZHANG Min1. 昆明理工大学信息工程与自动化学院 昆明 6505002. 云南民族大学数学与计算机科学学院 昆明 6505003. 云南省人工智能重点实验室 昆明 6505001. Faculty of Information Engineering and Automation, Kun-ming University of Science and Technology, Kunming 6505002. School of Mathematics and Computer Science, Yunnan MinzuUniversity, Kunming 650500 3. Yunnan Key Laboratory of Ar-tificial Intelligence, Kunming 650500第 48 卷 第 7 期自 动 化 学 报Vol. 48, No. 72022 年 7 月ACTA AUTOMATICA SINICAJuly, 2022依赖于平行语料的规模与质量, 只有当训练语料规模达到一定数量级时, 变分方法才会体现其优势.然而, 在低资源语言对上, 不同程度的都面临平行语料缺乏的问题, 因此如何利用相对容易获取的单语语料、实现语料扩充成为应用变分方法的前提.针对此问题, 本文采用能够同时利用平行语料和单语语料的半监督学习方式展开研究. 半监督神经机器翻译(Semi-supervised neural machine transla-tion)主要通过两种方式对单语语料进行利用:1)语料扩充−再训练: 利用小规模平行语料训练基础翻译模型, 在此模型基础上利用回译[8]等语料扩充方法对大规模单语语料进行翻译, 形成伪平行语料再次参与训练; 2)联合训练: 利用自编码[9−10] 等方法, 以平行语料和单语语料共同作为输入, 进行联合训练. 本文重点关注语料扩充后的变分方法应用, 因此采用语料扩充−再训练方式.k −1k 目前被较多采用的语料扩充方法为: 首先利用小规模平行语料训练基础翻译模型, 在此基础上通过回译将大规模单语语料翻译为伪平行语料, 进而组合两种语料进行再次训练. 因此, 基础翻译模型作为任务的起始点, 它的性能直接影响后续任务的执行质量. 传统提升基础翻译模型性能的手段限于使用深层神经网络和在解码端最高层网络应用注意力机制. 然而, 由于深层神经网络在应用于自然语言处理任务中时, 不同层次的神经网络侧重学习的特征不同: 低层网络倾向于学习词法和浅层句法特征, 高层网络则倾向于获取更好的句法结构特征和语义特征[11]. 因此, 很多研究者通过层级注意力机制, 利用神经网络每一层编码器产生的上下文表征指导解码. 层级注意力机制使高层网络的特征信息得以利用的同时, 也挖掘低层网络对输入序列的表征能力. 然而, 上述研究多采用层内融合方式实现层级注意力机制, 其基本方式为将 层上下文向量融入第 层的编码中. 事实上在低资源环境中,受限的语料规模易导致模型训练不充分, 在此情况下引入层级注意力, 可能会加重网络复杂性, 造成性能下降. 因此, 本文设想通过融入跨层注意力机制, 使低层表征能够跨越层次后对高层表征产生直接影响, 既能弥补因网络复杂性增加带来的性能损失, 又能更好地利用表征信息提升翻译效果. 除此以外, 由于在基础模型的训练过程中缺少双语监督信号, 导致利用其产生的伪平行语料中不可避免的存在大量的数据噪声, 而在增加使用层级注意力机制后, 并不能减少噪声, 相反, 噪声随着更多表征信息的融入呈正比例增长[12−13]. 在随后的再训练过程中, 虽然语料规模能够满足变分方法的需求, 但含有较多噪声的语料作为编码器的输入, 使训练在源头就产生了偏差, 因此对整个再训练过程均造成影x y 响. 针对上述问题, 本文提出了一种融入变分信息瓶颈的神经机器翻译方法. 首先利用小规模平行语料训练得到基础翻译模型, 在其基础上利用回译将大规模单语语料翻译为伪平行语料, 进而合并两种平行语料, 使语料规模达到能够较好地应用变分方法的程度. 在此过程中, 针对基础翻译模型的训练不充分问题, 通过引入跨层注意力机制加强不同层次网络的内部交互, 除了通过注意力机制学习高层网络编码器产生的语义特征之外, 也关注低层网络产生上下文表征的能力和对高层表征的直接影响.随后, 针对生成的语料中的噪声问题, 使用变分信息瓶颈[12]方法, 利用其信息控制特性, 在编码端输入(源语言 )与解码端输出(目标语言 )之间的位置引入中间表征, 通过优化中间表征的分布, 使通过瓶颈的有效信息量最大, 从而最大程度放行重要信息、忽略与任务无关的信息, 实现噪声的去除.本文的创新点包括以下两个方面: 1)通过融入跨层注意力机制加强基础翻译模型的训练, 在增强的基础翻译模型上利用回译产生伪平行语料、增大数据规模, 使其达到能够有效应用变分方法的程度.2)首次将变分信息瓶颈应用于神经机器翻译任务,在生成的语料的基础上, 利用变分特性提升模型的性能, 同时针对生成语料中的噪声, 利用信息瓶颈的控制特性进行去除. 概括来说, 方法整体实现的是一种语料扩充−信息精炼与利用的过程, 并预期在融合该方法的神经机器翻译中取得翻译效果的提升. 在IWSLT 和WMT 等数据集上进行的实验结果表明, 本文提出的方法能显著提高翻译质量.1 相关工作1.1 层级注意力机制注意力机制的有效性得到证明之后, 迅速成为研究者们关注的热点. 很多研究者在神经网络的不同层次上应用注意力机制构建层级注意力模型, 在此基础上展开训练任务. Yang 等[14]将网络划分为两个注意力层次, 第一个层次为 “词注意”, 另一个层次为 “句注意”, 每部分通过双向循环神经网络(Recurrent neural network)结合注意力机制实现文本分类. Pappas 等[15]提出了一种用于学习文档结构的多语言分层注意力网络, 通过跨语言的共享编码器和注意力机制, 使用多任务学习和对齐的语义空间作为文本分类任务的输入, 显著提升分类效果. Zhang 等[16]提出一种层次结构摘要方法, 使用分层结构的自我关注机制来创建句子和文档嵌入,通过层次注意机制提供额外的信息源来获取更佳的特征表示, 从而更好地指导摘要的生成. Miculi-7 期于志强等: 基于变分信息瓶颈的半监督神经机器翻译1679cich等[17]提出了一个分层关注模型, 将其作为另一个抽象层次集成在传统端到端的神经机器翻译结构中, 以结构化和动态的方式捕获上下文, 显著提升了结果的BLEU (Bilingual evaluation under-study)值. Zhang等[18]提出了一种深度关注模型,模型基于低层网络上的注意力信息, 自动确定从相应的编码器层传递信息的阈值, 从而使词的分布式表示适合于高层注意力, 在多个数据集上验证了模型的有效性. 研究者们通过融入层级注意力机制到模型训练中, 在模型之上直接执行文本分类、摘要和翻译等任务, 与上述研究工作不同的是, 本文更关注于跨层次的注意力机制, 并期待将融入跨层注意力机制的基础翻译模型用于进一步任务.1.2 单语语料扩充如何在低资源场景下进行单语语料的扩充和利用一直是研究者们关注的热点问题之一. 早在2007年, Ueffing等[19]就提出了基于统计机器翻译的语料扩充方法: 利用直推学习来充分利用单语语料库.他们使用训练好的翻译模型来翻译虚拟的源文本,将其与译文配对, 形成一个伪平行语料库. 在此基础上, Bertoldi等[20]通过改进的网络结构进行训练,整个过程循环迭代直至收敛, 取得了性能上的进一步提升. Klementiev等[21]提出了一种单语语料库短语翻译概率估计方法, 在一定程度上缓解了生成的伪平行语料中的重复问题. 与前文不同, Zhang等[22]使用检索技术直接从单语语料库中提取平行短语.另一个重要的研究方向是将基于单语语料库的翻译视为一个解密问题, 将译文的生成过程等同于密文到明文的转换[23−24].以上的单语语料扩充方法主要应用于统计机器翻译中. 随着深度学习的兴起, 神经机器翻译成为翻译任务的主流方法, 探索在低资源神经机器翻译场景下的语料扩充方法成为研究热点. Sennrich等[8]在神经机器翻译框架基础上提出了语料扩充方法.他们利用具有网络结构普适性的两种方法来使用单语语料. 第1种方法是将单语句子与虚拟输入配对,然后在固定编码器和注意力模型参数的情况下利用这些伪平行句对进行训练. 在第2种方法中, 他们首先在平行语料库上训练初步的神经机器翻译模型, 然后使用该模型翻译单语语料, 最后结合单语语料及其翻译构成伪平行语料, 第2种方法也称为回译. 回译可在不依赖于神经网络结构的情况下实现平行语料的构建, 因此广泛应用于半监督和无监督神经机器翻译中. Cheng等[25]提出一种半监督神经机器翻译模型, 通过将回译与自编码进行结合重构源与目标语言的伪平行语料, 取得了翻译性能上的提升. Skorokhodov等[26]提出了一种将知识从单独训练的语言模型转移到神经机器翻译系统的方法, 讨论了在缺乏平行语料和计算资源的情况下,利用回译等方法提高翻译质量的几种技术. Ar-tetxe等[27]利用共享编码器, 在两个解码器上分别应用回译与去噪进行联合训练, 实现了只依赖单语语料的非监督神经机器翻译. Lample等[28]提出了两个模型变体: 一个神经网络模型和一个基于短语的模型. 利用回译、语言模型去噪以及迭代反向翻译自动生成平行语料. Burlot等[29]对回译进行了系统研究, 并引入新的数据模拟模型实现语料扩充. 与上述研究工作不同的是, 本文同时关注于伪平行语料生成所依赖的基础翻译模型的训练. 在训练过程中, 不仅利用注意力机制关注高层网络中对句法结构和语义信息的利用, 同时也关注低层网络信息对高层网络信息的直接影响.1.3 变分信息瓶颈为了实现信息的压缩和去噪, Tishby等[30]提出基于互信息的信息瓶颈(Information bottleneck)方法. 深度神经网络得到广泛应用后, Alemi等[12]在传统信息瓶颈的基础上进行改进, 提出了适用于神经网络的变分信息瓶颈(Variational informa-tion bottleneck), 变分信息瓶颈利用深度神经网络来建模和训练, 通过在源和目标之间添加中间表征来进行信息过滤.在神经机器翻译中, 尚未发现利用变分信息瓶颈进行噪声去除的相关研究工作, 但是一些基于变分的方法近期已经在神经机器翻译中得到应用, 有效提高了翻译性能. Zhang等[7]提出一个变分模型,通过引入一个连续的潜在变量来显式地对源语句的底层语义建模并指导目标翻译的生成, 能够有效的提高翻译质量. Eikema等[31]提出一个双语句对的深层生成模型, 该模型从共享的潜在空间中共同生成源句和目标句, 通过变分推理和参数梯度化来完成训练, 在域内、混合域等机器翻译场景中证明了模型的有效性. Su等[32]基于变分递归神经网络, 提出了一种变分递归神经机器翻译模型, 利用变分自编码器将随机变量添加到解码器的隐藏状态中, 能够在不同的时间步长上进一步捕获依赖关系.2 模型本节首先介绍传统基于注意力机制的基础翻译模型, 接着介绍了融入跨层注意力机制的基础翻译模型. 区别于传统的基础翻译模型, 本文通过融入跨层注意力机制, 除关注高层编码器产生的上下文1680自 动 化 学 报48 卷表征向量之外, 也关注低层编码器产生的上下文表征向量对高层编码的直接影响. 最后介绍了变分信息瓶颈模型, 展示了利用该模型对回译方法生成的伪平行语料中的噪声进行去除的过程.2.1 传统注意力机制模型y t x =(x 1,x 2,···,x n )y =(y 1,y 2,···,y t −1),y t 传统方法中, 最初通过在解码端最高层网络引入注意力机制进行基础翻译模型的训练. 如图1所示的2层编解码器结构中, 它通过在每个时间步长生成一个目标单词 来进行翻译. 给定编码端输入序列 和已生成的翻译序列 解码端产生下一个词 的概率为g s t t 其中, 是非线性函数, 为在时间步时刻的解码端隐状态向量, 由下式计算得到f c t t 其中,是激活函数, 是 时刻的上下文向量, 其计算式为h j =[h j ;h j ]x j αt,j 其中, 是输入序列 的向量表征, 由前向和后向编码向量拼接得到. 权重的定义为e t,j s t −1h j 其中,是对 和 相似性的度量, 其计算式为k k −1通过在最高层网络引入注意力机制来改善语义表征、辅助基础翻译模型的训练, 能够有效地提升翻译性能, 但仅利用最高层信息的方式使得其他层次的词法和浅层句法等特征信息被忽略, 进而影响生成的伪平行语料质量. 针对此问题, 能够利用每层网络上下文表征的层级注意力机制得到关注, 成为众多翻译系统采用的基础方法. 这些系统往往采用层内融合方式的层级注意力机制, 如图2所示的编解码器结构中, 第 层的输入融合了 层的上下文向量和隐状态向量. 具体计算式为d k −1t =tanh (W d [s k −1t ;c k −1t ]+b d )(6)s k t =f (s k t −1,d k −1t)(7)p t =tanh (W p ([s r t ;c r t ])+b p )(8)f r 其中, 为激活函数, 为神经网络层数.AttentionAttentionMLP c 2y 2y 1x nx 2x 1〈GO 〉kd t c 2k −1k −1c t k −1s t k −1编码器解码器图 2 层内融合方式的层级注意力机制融入Fig. 2 Model with hierarchical attention mechanismbased on inner-layer merge2.2 跨层注意力机制模型c k t ,r c t层内融合方式加强了低层表征利用, 但难以使低层表征跨越层次对高层表征产生直接影响. 因此,本文设想利用跨层融合, 在利用低层表征的同时促进低层表征对高层表征的直接影响. 通过融入跨层注意力机制, 使各层特征信息得到更加充分的利用.如图3所示, 模型通过注意力机制计算每一层的上下文向量 在最高层对它们进行拼接, 得到跨层融合的上下文向量 s t 同样, 通过跨层拼接操作得到 , 随后通过非注意力分布注意力打分编码器c 2y 2x 2x 2x n〈GO 〉图 1 传统作用于最高层网络的注意力机制融入Fig. 1 Model with traditional attention mechanismbased on top-layer merge7 期于志强等: 基于变分信息瓶颈的半监督神经机器翻译1681p t p t softmax 线性变换得到 , 用于输入到 函数中计算词表中的概率分布s t =[s 1t ;s 2t ;···;s r t ](10)p t =tanh (W p ([s t ;c t ])+b p )(11)2.3 变分信息瓶颈模型X Y Z X X →Z →Y R IB (θ)Z X 在基础翻译模型的训练中, 通过融入不同层次的上下文向量来改善语义表征, 但也因此带来更多的噪声信息. 针对此问题, 本文通过在编解码结构中引入适用于神经网络的变分信息瓶颈方法来进行解决. 需要注意的是, 编解码结构中, 编码端的输入通过编码端隐状态隐式传递到解码端. 变分信息瓶颈要求在编码端输入与解码端最终输出之间的位置引入中间表征, 因此为了便于实现, 将变分信息瓶颈应用于解码端获取最终输出之前, 以纳入损失计算的方式进行模型训练, 其直接输入为解码端的隐状态, 以此种方式实现对编码端输入中噪声的过滤.具体流程为: 在给定的 到 的转换任务中, 引入 作为源输入 的中间表征, 构造从 的信息瓶颈 , 利用 实现对 中信息的筛选和过滤. 计算过程为R IB (θ)=I (Z,Y ;θ)−βI (Z,X ;θ)(13)I (Z,Y ;θ)Y Z Z X →Y 其中, 表示 和 之间的互信息量. 变分信息瓶颈的目标是以互信息作为信息量的度量, 通过学习编码 的分布, 使 的信息量最小, 强迫模型让最重要的信息流过信息瓶颈而忽略与任务无关的信息, 从而实现噪声的去除.D ={⟨x (n),y (n )⟩}Nn =1给定输入平行语料 , 神经机器翻译的标准训练目标是极大化训练数据的似然概率P (y |x ;θ)x →y θ其中, 是 的翻译模型, 为模型的参数集合. 训练过程中, 寻求极大化似然概率等价于寻求损失的最小化z =f (x,y <t )z y 本文引入信息瓶颈作为编码的中间表征, 构造从中间表征 到输出序列 的损失, 作为训练的交叉熵损失, 计算式为P (z |x ;θ)Q (z )同时加入约束, 目标为 的分布与标准正态分布 的KL 散度(Kullback-Leibler diver-gence)最小化, 在引入变分信息瓶颈之后, 训练过程的损失函数为λλ10−3其中, 为超参数, 实验结果表明, 设置为 时取得最优结果.D a,b ={⟨a (m ),b (m )⟩}Mm =1D x ={⟨x (n )⟩}Nn =1D a,b D x D x,y D b +y,a +x ={⟨b (m )+y (n ),a (m )+x (n )⟩}M +Nm,n =1D x ={⟨x (n )⟩}Nn =1D y ={⟨y (n )⟩}Nn =1D b +D y D a +D x ,图4显示了引入了变分信息瓶颈后的模型结构, 同样地, 为了利用不同层次的上下文表征信息,在变分信息瓶颈模型中也引入了跨层注意力机制.模型的输入为平行语料和伪平行语料的组合. 以给定小规模平行语料 和单语语料 为例, 表1展示了由原始小规模平行语料 和由单语语料 生成的伪平行语料 进行组合, 形成最终语料 的过程. 需要注意的是, 变分信息瓶颈是通过引入中间表征来实现去除源输入中的噪声信息, 对于单语语料 而言, 噪声信息存在于通过回译生成的对应伪语料 中. 因此在模型训练时, 需调换翻译方向, 将包含噪声信息的 作为源语言语料进行输入, 对其进行噪声去除. 而目标语言为不含噪声的 利于损失的计算.c 2k c 2y 2y 1x 2x 2x n〈GO 〉k −1AttentionAttention编码器解码器图 3 跨层融合方式的层级注意力机制融入Fig. 3 Model with hierarchical attention mechanismbased on cross-layer merge1682自 动 化 学 报48 卷表 1 语料组合结构示例Table 1 Examples of the combined corpus structure 语料类别源语言语料目标语言语料原始语料D a D b单语语料D x—伪平行语料D x D y组合语料D b+D y D a+D x3 实验设置3.1 数据集本文选择机器翻译领域的通用数据集作为平行语料来源, 表2显示了平行语料的构成情况. 为观察本文方法在不同规模数据集上的作用, 采用不同规模的数据集进行对比实验. 小规模训练语料中,英−越、英−中和英−德平行语料均来自IWSLT15数据集, 本文选择tst2012作为验证集进行参数优化和模型选择, 选择tst2013作为测试集进行测试验证. 大规模训练来自WMT14数据集, 验证集和测试集分别采用newstest2012和newstest2013.表3显示了单语语料的构成情况, 英−越和英−中翻译中, 英文和中文使用的单语语料来源于GIGAWORD数据集, 越南语方面为互联网爬取和人工校验结合处理后得到的1 M高质量语料. IWSLT 和WMT上的英−德翻译任务中, 使用的单语语料来源于WMT14数据集的单语部分, 具体由Euro-parl v7、News Commentary和News Crawl 2011组合而成. 本文对语料进行标准化预处理, 包括词切分、过长句对过滤, 其中, 对英语、德语还进行了去停用词操作. 本文选择BPE作为基准系统, 源端和目标端词汇表大小均设置为30000.表 3 实验使用的单语语料的构成, 其中越南语使用本文构建的单语语料Table 3 The composition of monolingual corpus, in which Vietnamese was collected by ourselves翻译任务语言数据集句数 (M)单语语料en↔vien GIGAWORD22.3vi None1en↔zhen GIGAWORD22.3zh GIGAWORD18.7en↔de(IWSLT15)en WMT1418de WMT1417.3en↔de(WMT14)en WMT1418de WMT1417.3 3.2 参数设置本文选择以下模型作为基准系统:1) RNNSearch模型: 编码器和解码器分别采编码器解码器SoftmaxVIBWord embedding (from original+pseudo corpus) A t t e n t i o n图 4 融入变分信息瓶颈后的神经机器翻译模型Fig. 4 NMT model after integrating variational information bottleneck表 2 平行语料的构成Table 2 The composition of parallel corpus语料类型数据集语言对训练集验证集测试集小规模平行语料IWSLT15en↔vi133 K15531268 IWSLT15en↔zh209 K8871261 IWSLT15en↔de172 K8871565大规模平行语料WMT14en↔de 4.5 M30033000注: en: 英语, vi: 越南语, zh: 中文, de: 德语.7 期于志强等: 基于变分信息瓶颈的半监督神经机器翻译1683用6层双向长短期记忆网络(Bi-directional long short-term memory, Bi-LSTM)和长短期记忆网络(Long short-term memory, LSTM)构建. 隐层神经元个数设置为1 000, 词嵌入维度设置为620.使用Adam 算法[33]进行模型参数优化, dropout 率设定为0.2, 批次大小设定为128. 使用集束宽度为4的集束搜索(Beam search)算法进行解码.2) Transformer 模型: 编码器和解码器分别采用默认的6层神经网络, 头数设置为8, 隐状态和词嵌入维度设置为512. 使用Adam 算法进行模型参数优化, dropout 率设定为0.1, 批次大小设置为4 096.测试阶段使用集束搜索算法进行解码, 集束宽度为4.利用IWSLT15数据集进行的小规模平行语料实验中, 本文参考了Sennrich 等[34]关于低资源环境下优化神经机器翻译效果的设置, 包括层正则化和激进dropout.3.3 评价指标本文选择大小写不敏感的BLEU 值[35]作为评价指标, 评价脚本采用大小写不敏感的multi-bleu.perl. 为了从更多角度评价译文质量, 本文另外采用RIBES 进行辅助评测. RIBES (Rank-based in-tuitive bilingual evaluation score)是另一种评测机器翻译性能的方法[36], 与BLEU 评测不同的是,RIBES 评测方法侧重于关注译文的词序是否正确.4 实验结果分析本节首先通过机器翻译评价指标对提出的模型进行量化评价, 接着通过可视化的角度对模型效果进行了分析.4.1 BLEU 值评测本文提出的方法和基准系统在不同翻译方向上的BLEU 值如表4所示, 需要注意的是, 为了应用变分信息瓶颈、实现对源端噪声信息进行去除, 最终翻译方向与基础翻译模型方向相反(具体原因见第2.3节中对表1的描述). 表4中RNNSearch 和Transformer 为分别在基线系统上, 利用基础模型进行单语语料回译, 接着将获得的组合语料再次进行训练后得到的BLEU 值. 表4同时展示了消融不同模块后的BLEU 值变化, 其中CA 、VIB 分别表示跨层注意力、变分信息瓶颈模块.通过实验结果可以观察到, 本文提出的融入跨层注意力和变分信息瓶颈方法在所有翻译方向上均取得了性能提升. 以在IWSLT15数据集上的德→英翻译为例, 相较Transformer 基准系统, 融入两种方法后提升了0.69个BLEU 值. 同时根据德英翻译任务结果可以观察到, BLEU 值的提升幅度随着语料规模的上升而减小. 出现该结果的一个可能原因是在低资源环境下, 跨层注意力的使用能够挖掘更多的表征信息、使低层表征对高层表征的影响更为直接. 而在资源丰富的环境下, 平行语料规模提升所引入的信息与跨层注意力所挖掘信息在一定程度上有所重合. 另一个可能原因是相对于资源丰富环境, 低资源环境产生的伪平行语料占组合语料的比例更大, 变分信息瓶颈进行了更多的噪声去除操作.表 4 BLEU 值评测结果(%)Table 4 Evaluation results of BLEU (%)模型BLEUen →vi vi →en en →zh zh →en en →de (IWSLT15)de →en (IWSLT15)en →de (WMT14)de →en (WMT14)RNNSearch 26.5524.4721.1819.1525.0328.5126.6229.20RNNSearch+CA 27.0424.9521.6419.5925.3928.9427.0629.58RNNSearch+VIB 27.3525.1221.9419.8425.7729.3127.2729.89RNNSearch+CA+VIB27.83*25.61*22.3920.2726.14*29.66*27.61*30.22*△ +1.28+1.14+1.21+1.12+1.11+1.15+0.99+1.02Transformer 29.2026.7323.6921.6127.4830.6628.7431.29Transformer+CA 29.5327.0023.9521.8227.7430.9828.9331.51Transformer+VIB 29.9627.3824.3022.1328.0431.2429.1631.75Transformer+CA+VIB30.17*27.56*24.4322.3228.11*31.35*29.25*31.89*△+0.97+0.83+0.74+0.71+0.63+0.69+0.51+0.60△p <0.05注: 表示融入CA+VIB 后相较基准系统的BLEU 值提升, * 表示利用bootstrap resampling [37] 进行了显著性检验 ( )1684自 动 化 学 报48 卷。
A Cross-Layer Approach to Performance Monitoringof Web ServicesNicolas Repp,Rainer Berbner,Oliver Heckmann,and Ralf SteinmetzTechnische Universit¨a t DarmstadtMultimedia Communications Lab(KOM)Merckstrasse25,64283Darmstadt,Germanyrepp@kom.tu-darmstadt.deAbstract.An increasing amount of applications are currently built as Web Ser-vice compositions based on the TCP/IP+HTTP protocol stack.In case of anydeviations from desired runtime-behavior,problematic Web Services have to besubstituted and their execution plans have to be updated accordingly.One chal-lenge is to detect deviations as early as possible allowing timely adaption of exe-cution plans.We advocate a cross-layer approach to detect bad performance andservice interruptions much earlier than by waiting for their propagation throughthe full protocol stack.This position paper describes an approach to gain detailed real-time informationabout Web Service behavior and performance based on a cross-layer analysis ofthe TCP/IP+HTTP protocols.In this paper we focus especially on TCP.The re-sults are used to make decisions supporting service selection and replanning inservice-oriented computing scenarios.Furthermore,generic architectural compo-nents are proposed implementing the functionality needed which can be used indifferent web-based scenarios.1IntroductionAlmost every Internet user has encountered problems while using services in the Inter-net,e.g.,browsing the World-Wide Web or using Email.Long to infinite response times due to congestion or connection outage,non-resolvable URLs,or simplefile-not-found errors are some of the most common ones.Human users tend to beflexible in case of any service”misbehavior”.Users wait and check back later or even select a different service if the originally requested service is not available.In contrast,computer systems as service consumers are not asflexible.Appropriate strategies to handle those runtime events have to be implemented during design time of the computer system.Services are the key building block of service-oriented computing.A service is a self-describing encapsulation of business functionality(with varying granularity)ac-cording to[1].Following the service-oriented computing paradigm,applications can be assembled out of several independent,distributed and loosely-coupled services[2]. Those services can be provided even by third parties.One option to implement services from a technical perspective is the use of Web Services.Web Services are based on dif-ferent XML-based languages for data exchange and interface description,e.g.,SOAP and the Web Service Description Language(WSDL).For the transport of data and theFig.1.Modified W3C Web Services Architecture Stack[3]Web Service invocation mainly the Transmission Control Protocol(TCP)/Internet Pro-tocol(IP)suite(e.g.,RFC793,[4],or[5])as well as the Hypertext Transfer Protocol (HTTP-e.g.,RFC2616or[6])are used.Figure1shows the W3C Web Services Archi-tecture Stack enhanced by alternative Web Service technologies and the communication protocols used.It will be the basis for our further considerations.In order to build applications from different existing Web Services the following generic phases are needed[7]:First,suitable Web Services have to be selected accord-ing to the functional and non-functional requirements of the application.Second,the selected Web Services have to be composed to an execution plan.Hereto,a composition can be described,e.g.,on basis of the Business Process Execution Language(BPEL) [8].In the next step the execution plan can be processed.During the execution phase it is possible that parts of the composition do not act as expected with regard to the non-functional requirements.Reasons for misbehavior of Web Services are manyfold, e.g.,server errors while processing a request,network congestion or network outages. Therefore,it is necessary to select alternative Web Services and to replan the Web Ser-vice execution[9].Replanning is always a trade-off between the costs of creating new plans to fulfill the overall non-functional requirements and the costs of breaking the requirements[10].Timely action is required to reduce the delay in the execution of an application due to replanning and substitution of Web Services.Hence,we propose a proactive approach initiating countermeasures as soon as there is evidence that a de-viation might occur in the near future with a certain probability p.To start replanning before the deviation happens allows replanning to be carried out in parallel to the ser-vice execution itself.The results of replanning have to be discarded with probability 1−p as the alternative plans are not needed.Furthermore,current approaches often lack detailed information about the status of a Web Service due to the information hiding implemented in the layer model ofthe TCP/IP+HTTP protocol stack underlying Web Services.For this,we advocate a cross-layer approach to detect bad performance and service interruptions.Cross-layer analysis allows decisions based on deeper knowledge of the current situation as well as decisions made much earlier than by waiting for information propagating through the full protocol stack.The rest of this position paper is structured as follows.In the next section we de-scribe Quality-of-Service(QoS)and its meaning for Web Services.We especially fo-cus on performance as a part of Web Service QoS.Afterwards,the relation between TCP/IP+HTTP and Web Service performance is discussed.Our cross-layer approach to performance monitoring an performance anomaly detection of Web Services is intro-duced thereafter.The paper closes with a conclusion and an outlook on future work.2Quality-of-Service and Performance of Web ServicesIn this section we discuss QoS with regard to Web Services and Web Service composi-tions with a focus on Web Service performance.2.1Quality-of-Service with regard to Web ServicesSimilar to QoS requirements in traditional networks,there is a need to describe and manage QoS of Web Services and Web Service compositions.Generally,QoS defines non-functional requirements on services independent from the layer they are related to. QoS can be divided into measurable and non-measurable parameters.The most com-mon measurable parameters are performance-related,e.g.,throughput,response time, and latency.Additionally,parameters like availability,error-rate,as well as various non-measurable parameters like reputation and security are of importance for Web Services [10][11].The meaning of QoS requirements can differ between service providers and service requesters in a service-oriented computing environment[11].From a service providers’perspective,providing enough capacity with the quality needed to fulfill Service Level Agreements(SLA)with different customers is a core issue.Service re-questers are more focused on managing bundles of Web Services from different ven-dors in order to implement their business needs.Therefore,management of QoS re-quirements is done on aggregations of Web Services,to a lesser extend on single Web Services.There is a variety of other definitions of Web Service QoS.A more extensive ap-proach identifies the following requirements[12]:performance,reliability,scalability, capacity,robustness,exception handling,accuracy,integrity,accessibility,availability, interoperability,security,and network-related QoS requirements.Especially the last re-quirement is of further interest.As many requirements of Web Service QoS are directly related to the underlying network and its QoS,implementations of network QoS mech-anisms,e.g.,Differentiated Services(DiffServ)or the Resource Reservation Protocol (RSVP),are also covered by the definition as well.2.2Performance of Web ServicesPerformance of Web Services is not a singular concept.Rather,it consists of several concepts which themselves are connected to different metrics and parameters.Again, there are several definitions of Web Service performance.We will use the definition provided by the Web Services Architecture Working Group of the W3C as a founda-tion for our own defintion.According to the W3C,performance is defined in terms of throughput,reponse time,latency,execution time,and transaction time[12].Both execution time and latency are sub-concepts of the W3Cs definition of response time. Transaction time describes the time needed to process a complete transaction,i.e.,an interaction consisting of several requests and responses belonging together.For this paper,we define performance in terms of throughput and response time. Response time is the time needed to process a query,from sending the request until receiving the response[13].Response time can be further divided into task processing time,network processing time,i.e.,time consumed while traversing the protocol stacks of source,destination,and intermediate systems,as well as network transport time itself. In case of an error during the processing of a request or a response,the response time measures the time from a request to the notification of an error.We define response time as follows:t response(ws)=t task(ws)+t stack(ws)+t transport(ws)A large fraction of a web service’s response time is determined by the processing time for requests and their respective messages in both intermediate systems and end-points. For the measurement of the response time,the encapsulation of data into XML mes-sages and vice versa,compression and decompression of data,as well as encryption and decryption of messages also have to be taken into account.Furthermore,time for con-nection setup,for the negotiation of the connections parameters as well as the amount of time used for authentication are part of the response time as well.Throughput,measured in connections,requests or packets per second,describes the capability of a Web Service provider to process concurrent Web Service requests.De-pending on the layer,different types of connections can be the basis for measurements, e.g.TCP connections,HTTP connections,or even SOAP interactions.We define the throughput of a Web Services as:throughput(ws)=#requests(ws)3A Cross-layer Approach to Performance Monitoring and Anomaly DetectionIn this section we describe an approach for performance monitoring and performance anomaly detection based on packet capturing and the application of simple heuristics. Therefore,we analyze IP,TCP,and HTTP data.The analysis of SOAP is not in scope of this paper,as we want to stay independent of a certain Web Service technology.Our approach can be applied to various alternative Web Service technologies as well,e.g., XML-Remote Procedure Call(XML-RPC)or Representational State Transfer(REST). Nevertheless,in our examples we use SOAP as it is the most common Web Service technology in use.3.1Protocol Parameters for Performance MonitoringConsider the simple Web Service invocation of a single Web Service as depicted in Figure2.A service requester generates a SOAP request and sends the message using HTTP to the service provider for further processing.The message has to pass several in-termediate systems on its way between the interaction’s endpoints.The SOAP response message is again transported using HTTP.Service ServiceFig.2.Simple Web Service interactionDuring data transfer several problems can occur,which all have an impact on Web Service execution.Beginning with the network layer,we may face routing problems, e.g.,hosts which are not reachable,congestion in Internet routers as well as traffic bursts.Additionally,on transport layer there are also potential pitfalls like the retrans-mission of packets due to packet loss or connection setup problems generating delays. Finally,there are also some potential problems on application layer with regard to Web Services for example in form of resources,which are not existing or not accessable for HTTP or problems in processing of SOAP messages due to incomplete or non-valid XML data.Although,many of the above problems are solved in modern protocol stack imple-mentations,we can use the knowledge about them to define measurement points for performance monitoring.Depending on the problems in scope different protocol pa-rameters have to be used.Table1gives an overview of measurement points on differentprotocol layers.We will use the transport layer parameters as an example to derive metrics and heuristics for performance anomaly detection in the following section.ProtocolICMP messagesSize of advertising windowRoundtrip time(RTT)Sequence numbers in useFlags used in packetsInformation about timersHeader informationTable1.Measuring points per protocol layer3.2Metrics and Heuristics for Performance Anomaly DetectionAs noted in Section2.1we can differentiate between the requirements of service re-questers and service providers.To visualize our concepts we will focus on the service requester’s perspective in this position paper.Before basic heuristics are proposed we present metrics based on the parameters presented in Table1,which will be the founda-tion of our heuristics.We propose several metrics based on parameters of the transport layer protocol:–M1-Average throughput in bytes per second(BPS).–M2-Throughput based on a moving average over window with size n seconds in BPS.–M3-Throughput based on exponential smoothing(first degree)withαvarying in BPS.–M4-Roundtrip time based on a moving average over window with size n segments in seconds per segment.–M5-Number of gaps in sequence numbers based on a moving average over window with size n seconds in number of gaps per second.The aggregation of single metrics in combination with the usage of appropriate thresholds allows us to build heuristics in order to detect anomalies with performance impact.The following two simple heuristics show the idea how to design heuristics based on the metrics discussed.Both were derived from experimentations in our Web Service test environment.–H1Requester:M1(or M2,M3)in aggregation with M4,i.e.,throughput combined with RTT.–H2Requester:M4in aggregation with M5,i.e.,RTT combined with the amount of gaps in TCP sequence numbers.Singular metrics are in some cases not sufficient for robust monitoring,e.g.,M5without any information about RTT does not offer useful information.In addition to those transport layer based heuristics,further parameters from other protocol layers and the respective metrics can be combined in order to create different cross-layer heuristics.Nevertheless,it is important that metrics and the related heuristics have to be calculated in an efficient way in order to keep additional processing times of our approach low.3.3Exemplary Evaluation of Our ApproachTo show the feasibility of our approach we set up an experiment.The test environment consists of a1.4GHz Centrino with1.256GByte RAM running Windows XP as ser-vice requester and a1.42GHz G4with1GByte RAM running Mac OS X as service provider.Apache Tomcat5.5.17is used as an application server.Both systems use Java 1.5and Axis1.4as SOAP implementation.They are connected by100MBit/s ethernet. For packet capturing windump v3.9.3is used.First,we measure the response time of a Web Service in our test environment.As payload we use SOAP messages of variable size.Table2shows the results of measuring 20individual runs both with and without network outage for a payload of20MByte,a test scenario,which was already implemented in our test environment.Similar results can be observed with a payload work outages are equally distributed t response(ws)[ms]maximum8,7438,891601,204604,186Table2.SOAP response timesin the interval[0;max(t response(ws)w/o outage)].A network outage is modelled as a permanent100%packet loss,i.e.,without a restart of the connection.Other scenarios, e.g.,varying or temporary packet loss,are not in focus of this position paper.As Table 2shows,the response time of our Web Service varies between8.9seconds(without outage)and10.07minutes(with outage)for a20MByte payload.rtt[ms]maximum0.220.31Table3.Roundtrip timesIn a next step,we apply H1Requester on our sample with network outages.Espe-cially the roundtrip time extracted from TCP packets can be used as trend estimate for the overall response time in our scenario.Table3shows the average roundtrip times of ing a moving average of the roundtrip times measured as a benchmarkfor the roundtrip time of the packet in transfer,a warning to the replanning system can be sent,e.g.,if the estimated time(or a multiple)is exceeded twice or more in a row. Unfortunately,throughput was not as good as the RTT as an indicator for performance anomalies in the given scenario.3.4Identification of Required Architectural ComponentsIn order to implement our ideas several architectural components are needed.The key building blocks are depicted in Figure3.Fig.3.Proposed architectural componentsThe upper part of Figure3describes existing generic components used for planning and executing of Web Service compositions.The Interface allows deployment of work-flows and configuration,the(Re-)Planning Component generates and adapts execution plans,which are thereafter executed by an Orchestration Engine.We propose the use of our Web Service Quality-of-Service Architectural Extension(WSQoSX)as imple-mentation means for the functionality needed.WSQoSX already supports planning and replanning of compositions[7][10].The lower part of thefigure describes the two core components of our approach in addition to the protocol stack.This enhanced architectural blueprint is named Web Service-Service Monitoring Extension(WS-SMX).The Monitor specifies a compo-nent capable of eavesdropping of the network traffic between service requester and provider.It also implements pre-filtering of the data passing by reducing it to the pro-tocol data of interest.Its data is passed to a Detector component,which is responsiblefor the data analysis and therefore the performance anomaly detection.The Detector component will implement the heuristics discussed in Section3.2.The Orchestration Engine initializes the Detector,which itself prepares the Monitor.The Detector analy-ses the data received by the Monitor and triggers the(Re-)Planning Component in case of any criticalfindings.Additionally,the Detector component can be configured using the Interface.Both Monitor and Detector are implemented in afirst version in our test environment based on Java1.5in combination with libpcap for packet capturing.4Related WorkAs our approach is based on research of various domains this section gives an overview of related work in those domains.Gschwind et al.[14]describe WebMon,a perfor-mance analysis system with focus on Web transactions,i.e.transactions between a Web browser and a Web server.Monitoring is done on basis of HTTP.Web Services as re-mote method invocations as well as a further processing of the results of the analysis are not in scope of their paper.Similar mechanisms as the ones proposed by us are im-plemented in the commercial software package VitalSuite by Lucent,which is used for capacity planning and QoS management in large networks.VitalSuite can also analyze different protocol layers simultaneously.In contrast to the system we propose,Vital-Suite’s focus is on reporting for end-users instead of automated management.A more detailed view on performance management of Web Services is discussed by Schmi-etendorf et al.[15].The Web Services Trust Center(WSTC)allows Web Services to be registered at and measured by an independent third party for SLA management.WSTC enables the monitoring of performance and availability of Web Services,but not under real-time requirements.The management of Web Service compositions,their orchestration as well as their optimization and planning is emphasized in various papers,partly mentioned in the introduction.Of further interest in that domain is the Web Service Manager(WSM) introduced by Casati et al.[16]focusing on the business perspective of Web Service management,e.g.,detecting and measuring SLA violations.Fundamental work in the area of packet capturing,its justification and optimization was carried out e.g.,by Feldmann[17]and Mao et al.[18].Both do not focus on poten-tial areas of application for packet capturing but on measurement itself.Feldmann uses cross-layer capturing and analysis of TCP and HTTP for later Web performance studies. Mao et al.describe both drawbacks and advantages of performance analysis of Web ap-plications based on packet capturing mechanisms.Furthermore,a reliable and efficient approach for monitoring in distributed systems based on dispatching is discussed.The idea of anomaly detection to predict certain critical situations is already used, e.g.,in the area of network security,especially in network intrusion detection.Mainiko-poulos et al.describe the use of statistical methods applied to network usage traces for anomaly detection,e.g.,an attack on a networked system[19].Another area of appli-cation is discussed by Yuan et al.[20].They propose a system for automated problem diagnosis in applications based on system event traces.The correlation of current traces and patterns of well known problems allows an automatic identification of problemsources and prediction of possible system errors.Furthermore,the authors use statisti-cal learning and classifying methods to dynamically adapt and improve their system. 5Conclusion and Future WorkIn this position paper we show that it can be beneficial to use information gathered on different protocol layers for decision support.We present an approach and several architectural components,which use hidden,low layer technical information for proac-tive replanning of Web Service compositions.As this is a position paper there are still some open issues we are researching.We are currently testing machine learning algo-rithms for anomaly detection.Furthermore,we are working on enhancements of ex-isting optimization models for Web Service compositions to support replanning[10]. Additionally,we will test our approach from a service requester’s perspective in real world scenarios,using Web Services available to the public,e.g.,from Amazon or via Xmethods.Using our approach for proactive replanning is not limited to SOAP Web Services. As we are collecting our data on lower layers,the type of Web Service can be ex-changed,e.g.,REST and XML-RPC based Web Services can also be supported.But we are not even limited to Web Services as an area of application.The approach can be of benefit,e.g.,to enhance Web browsers to detect network problems in a faster way. AcknowledgmentsThis work is supported in part by E-Finance Lab e.V.,Frankfurt am Main. References1.Papazoglou,M.P.:Service-oriented computing:Concepts,characteristics and directions.In:Proceedings of the Fourth International Conference on Web Information Systems Engineer-ing(WISE03).(December2003)3–122.Bichler,M.,Lin,K.J.:Service-oriented computing.IEEE Computer39(3)(March2006)99–1013.Booth,D.,Haas,H.,McCabe,F.,Newcomer,E.,Champion,M.,Ferris,C.,Orchard,D.:Webservices architecture(2004./TR/ws-arch/,accessed:2006/07/02)4.Stevens,W.R.:TCP/IP illustrated(vol.1):the protocols.Addison-Wesley Longman Pub-lishing Co.,Inc.,Boston,MA,USA(1994)5.Tanenbaum,A.S.:Computer Networks,Fourth Edition.Prentice Hall,Indianapolis,Indiana,USA(August2002)6.Mogul,J.C.:Clarifying the fundamentals of http.In:WWW’02:Proceedings of the11thinternational conference on World Wide Web.(May2002)25–367.Berbner,R.,Grollius,T.,Repp,N.,Heckmann,O.,Ortner,E.,Steinmetz,R.:An approachfor the management of service-oriented architecture(soa)based application systems.In: Proceedings of the Workshop Enterprise Modelling and Information Systems Architectures (EMISA2005).(October2005)208–2218.Curbera,F.,Khalaf,R.,Mukhi,N.,Tai,S.,Weerawarana,S.:The next step in web services.Commun.ACM46(10)(2003)29–349.Canfora,G.,Penta,M.D.,Esposito,R.,Villani,M.L.:Qos-aware replanning of compos-ite web services.In:Proceedings of the IEEE International Conference on Web Services (ICWS’05).(July2005)121–12910.Berbner,R.,Spahn,M.,Repp,N.,Heckmann,O.,Steinmetz,R.:An approach for replanningof web service workflows.In:Proceedings of the12th Americas Conference on Information Systems(AMCIS’06).(August2006)11.Menasc´e,D.A.:Qos issues in web services.IEEE Internet Computing6(6)(2002)72–7512.Lee,K.C.,Jeon,J.H.,Lee,W.S.,Jeong,S.H.,Park,S.W.:Qos for web services:Require-ments and possible approaches(2003.http://www.w3c.or.kr/kr-office/TR/2003/ws-qos/,ac-cessed:2006/07/03)13.Jain,R.:The art of computer systems performance analysis:techniques for experimentaldesign,measurement,simulation,and modeling.John Wiley&Sons,Inc.,New York,NY, USA(1991)14.Gschwind,T.,Eshghi,K.,Garg,P.K.,Wurster,K.:Webmon:A performance profiler for webtransactions.In:Proc.of the4th IEEE Int’l Workshop on Advanced Issues of E-Commerce and Web-Based Information Systems-WECWIS2002.(June2002)171–17615.Schmietendorf,A.,Dumke,R.,Stojanov,S.:Performance aspects in web service-basedintegration solutions.In:Proc.of the21st UK Performance Engineering Workshop-UKPEW2005.(July2005)137–15216.Casati,F.,Shan,E.,Dayal,U.,Shan,M.C.:Business-oriented management of web services.Commun.ACM46(10)(2003)55–6017.Feldmann,A.:Blt:Bi-layer tracing of http and tcp/works33(1-6)(2000)321–33518.Mao,Y.,Chen,K.,Wang,D.,Zheng,W.:Cluster-based online monitoring system of webtraffic.In:WIDM’01:Proceedings of the3rd international workshop on Web information and data management.(November2001)47–5319.Manikopoulos,C.,Papavassiliou,S.:Network intrusion and fault detection:a statisticalanomaly approach.IEEE Communications Magazine40(10)(October2002)76–8220.Yuan,C.,Lao,N.,Wen,J.R.,Li,J.,Zhang,Z.,Wang,Y.M.,Ma,W.Y.:Automated knownproblem diagnosis with event traces.In:Proceedings of EuroSys2006.(April2006)375–388。
