Constructing and Dynamically Maintaining Perspective-based Agent Models for Command and Con

英语例句软岩组成的高边坡The English language is a rich and diverse means of communication, offering a vast array of vocabulary and grammatical structures to convey a wide range of ideas and concepts. One particularly interesting aspect of the English language is the use of sentences to describe various phenomena and situations. In this essay, we will explore the topic of "English Sentences - Soft Rock Slope," delving into the nuances of how the English language can be used to effectively communicate information about this geological feature.Soft rock slopes are a common geological formation found in many parts of the world. These slopes are characterized by the presence of rock formations that are relatively soft and easily eroded, often consisting of materials such as shale, siltstone, or mudstone. These types of rock formations can be prone to landslides and other natural hazards, making them an important consideration for both geologists and civil engineers.When describing a soft rock slope in English, one might use a sentence such as "The soft rock slope was covered in a layer of loosedebris and vegetation." This sentence conveys several key pieces of information about the slope, including its composition (soft rock), the presence of loose debris and vegetation on the surface, and the overall visual appearance of the feature.Another example sentence could be "The steep soft rock slope posed a significant challenge for the construction of the new highway." This sentence highlights the potential hazards associated with a soft rock slope, specifically the steepness of the slope and the challenges it presents for infrastructure development.In addition to describing the physical characteristics of a soft rock slope, English sentences can also be used to convey information about the processes that shape and influence these geological features. For instance, the sentence "Heavy rainfall caused the soft rock slope to experience significant erosion and landslides" would indicate that the slope is susceptible to the effects of water and weather, leading to the degradation of the rock formations.Furthermore, English sentences can be used to discuss the scientific and technical aspects of soft rock slopes, such as their geological composition, the mechanisms of erosion and slope failure, and the methods used to study and analyze these features. For example, the sentence "The geologists conducted a detailed analysis of the soft rock slope, using core samples and geophysical surveys to determinethe underlying rock structure and potential for slope instability" would convey the technical nature of the investigation and the various tools and techniques employed.In the context of civil engineering and infrastructure development, English sentences can be used to describe the challenges and considerations involved in constructing and maintaining structures on or near soft rock slopes. A sentence like "The engineers had to design a specialized retaining wall system to stabilize the soft rock slope and prevent further erosion and landslides" would highlight the need for specialized engineering solutions to address the unique characteristics of this type of geological formation.Beyond the purely descriptive aspects, English sentences can also be used to discuss the environmental and societal impacts of soft rock slopes. For instance, the sentence "The erosion of the soft rock slope led to the destruction of several homes and the displacement of local residents" would draw attention to the potential human consequences of slope instability and the importance of understanding and mitigating these risks.In conclusion, the English language offers a rich and versatile set of tools for describing and communicating information about soft rock slopes. From the physical characteristics of these geological features to the scientific, engineering, and societal implications, Englishsentences can be crafted to convey a wide range of information and perspectives. By mastering the use of English sentences, individuals can effectively share their knowledge and insights about soft rock slopes, contributing to our understanding of this important aspect of the natural world.。

04上（66）data effectively is crucial for success in today’s competitive environment. Managers must know how to use a variety of tools.Integrated data takes information from different sources and puts it together in a meaningful and useful way. One of the difficulties of this is the （67）in hardware and software （68）integration uses a base document that contains copies of other objects. （69）integration uses a base document that contains the current or most recent version of the source document it contains.（70）provides an overview of the program written in “plain” English , without the computer syntax.（66）A. Generalizing B. Sharing C. General-using D.Globalizing（67）A. similarity B. interoperability C. diversity D.interaction（68）A. Simulated B. Duplicated C.Dynamic D.Static（69）A. Linked B. pointed C.Dynamic D.Static（70）A.High-level language B.Decision treeC.PseudocodeD.Flowchart参考译文在当今的竞争环境下，要想取得成功，有效地共享数据是十分重要的。

Network Working Group R. DromsRequest for Comments: 2131 Bucknell UniversityObsoletes: 1541 March 1997Category: Standards TrackDynamic Host Configuration ProtocolStatus of this memoThis document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions forimprovements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited.AbstractThe Dynamic Host Configuration Protocol (DHCP) provides a framework for passing configuration information to hosts on a TCPIP network. DHCP is based on the Bootstrap Protocol (BOOTP) [7], adding thecapability of automatic allocation of reusable network addresses and additional configuration options [19]. DHCP captures the behavior of BOOTP relay agents [7, 21], and DHCP participants can interoperate with BOOTP participants [9].Table of Contents1. Introduction. . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1 Changes to RFC1541. . . . . . . . . . . . . . . . . . . . . . 3 1.2 Related Work. . . . . . . . . . . . . . . . . . . . . . . . . 4 1.3 Problem definition and issues . . . . . . . . . . . . . . . . 4 1.4 Requirements. . . . . . . . . . . . . . . . . . . . . . . . . 5 1.5 Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 61.6 Design goals. . . . . . . . . . . . . . . . . . . . . . . . . 62. Protocol Summary. . . . . . . . . . . . . . . . . . . . . . . 8 2.1 Configuration parameters repository . . . . . . . . . . . . . 112.2 Dynamic allocation of network addresses . . . . . . . . . . .123. The Client-Server Protocol. . . . . . . . . . . . . . . . . . 13 3.1 Client-server interaction - allocating a network address. . . 13 3.2 Client-server interaction - reusing a previously allocatednetwork address . . . . . . . . . . . . . . . . . . . . . . . 173.3 Interpretation and representation of time values. . . . . . . 20 3.4 Obtaining parameters with externally configured networkaddress . . . . . . . . . . . . . . . . . . . . . . . . . . . 203.5 Client parameters in DHCP . . . . . . . . . . . . . . . . . . 21 3.6 Use of DHCP in clients with multiple interfaces . . . . . . . 223.7 When clients should use DHCP. . . . . . . . . . . . . . . . .224. Specification of the DHCP client-server protocol. . . . . . . 22Droms Standards Track [Page 1]RFC 2131 Dynamic Host Configuration Protocol March 19974.1 Constructing and sending DHCP messages. . . . . . . . . . . .22 4.2 DHCP server administrative controls . . . . . . . . . . . . . 25 4.3 DHCP server behavior. . . . . . . . . . . . . . . . . . . . . 264.4 DHCP client behavior. . . . . . . . . . . . . . . . . . . . .345. Acknowledgments. . . . . . . . . . . . . . . . . . . . . . . .426. References . . . . . . . . . . . . . . . . . . . . . . . . . .427. Security Considerations. . . . . . . . . . . . . . . . . . . .438. Author's Address . . . . . . . . . . . . . . . . . . . . . . .44A. Host Configuration Parameters . . . . . . . . . . . . . . . .45 List of Figures1. Format of a DHCP message . . . . . . . . . . . . . . . . . . . 92. Format of the 'flags' field. . . . . . . . . . . . . . . . . .113. Timeline diagram of messages exchanged between DHCP client and servers when allocating a new network address. . . . . . . . . 154. Timeline diagram of messages exchanged between DHCP client and servers when reusing a previously allocated network address. . 185. State-transition diagram for DHCP clients. . . . . . . . . . .34 List of Tables1. Description of fields in a DHCP message. . . . . . . . . . . .102. DHCP messages. . . . . . . . . . . . . . . . . . . . . . . . .143. Fields and options used by DHCP servers. . . . . . . . . . . .284. Client messages from various states. . . . . . . . . . . . . .335. Fields and options used by DHCP clients. . . . . . . . . . . .37 1. IntroductionThe Dynamic Host Configuration Protocol (DHCP) provides configuration parameters to Internet hosts. DHCP consists of two components: a protocol for delivering host-specific configuration parameters from aDHCP server to a host and a mechanism for allocation of networkaddresses to hosts.DHCP is built on a client-server model, where designated DHCP server hosts allocate network addresses and deliver configuration parameters to dynamically configured hosts. Throughout the remainder of this document, the term "server" refers to a host providinginitialization parameters through DHCP, and the term "client" refers to a hostrequesting initialization parameters from a DHCP server.A host should not act as a DHCP server unless explicitly configured to do so by a system administrator. The diversity of hardware and protocol implementations in the Internet would preclude reliable operation if random hosts were allowed to respond to DHCP requests. For example, IP requires the setting of many parameters within the protocol implementation software. Because IP can be used on many dissimilar kinds of network hardware, values for those parameters cannot be guessed or assumed to have correct defaults. Also,distributed address allocation schemes depend on a polling/defenseDroms Standards Track [Page 2]RFC 2131 Dynamic Host Configuration Protocol March 1997mechanism for discovery of addresses that are already in use. IP hosts may not always be able to defend their network addresses, so that such a distributed address allocation scheme cannot beguaranteed to avoid allocation of duplicate network addresses.DHCP supports three mechanisms for IP address allocation. In"automatic allocation", DHCP assigns a permanent IP address to aclient. In "dynamic allocation", DHCP assigns an IP address to a client for a limited period of time (or until the client explicitly relinquishes the address). In "manual allocation", a client's IP address is assigned by the network administrator, and DHCP is used simply to convey the assigned address to the client. A particular network will use one or more of these mechanisms, depending on the policies of the network administrator.Dynamic allocation is the only one of the three mechanisms thatallows automatic reuse of an address that is no longer needed by the client to which it was assigned. Thus, dynamic allocation isparticularly useful for assigning an address to a client that will be connected to the network only temporarily or for sharing a limited pool of IP addresses among a group of clients that do not needpermanent IP addresses. Dynamic allocation may also be a good choice for assigning an IP address to a new client being permanentlyconnected to a network where IP addresses are sufficiently scarce that it is important to reclaim them when old clients are retired. Manual allocation allows DHCP to be used to eliminate the error-prone process of manually configuring hosts with IP addresses inenvironments where (for whatever reasons) it is desirable to manage IP address assignment outside of the DHCP mechanisms.The format of DHCP messages is based on the format of BOOTP messages, to capture the BOOTP relay agent behavior described as part of the BOOTP specification [7, 21] and to allow interoperability ofexisting BOOTP clients with DHCP servers. Using BOOTP relay agents eliminates the necessity of having a DHCP server on each physical networksegment.1.1 Changes to RFC 1541This document updates the DHCP protocol specification that appears in RFC1541. A new DHCP message type, DHCPINFORM, has been added; see section 3.4, 4.3 and 4.4 for details. The classing mechanism for identifying DHCP clients to DHCP servers has been extended to include "vendor" classes as defined in sections 4.2 and 4.3. The minimum lease time restriction has been removed. Finally, many editorial changes have been made to clarify the text as a result of experience gained in DHCP interoperability tests.Droms Standards Track [Page 3]RFC 2131 Dynamic Host Configuration Protocol March 19971.2 Related WorkThere are several Internet protocols and related mechanisms that address some parts of the dynamic host configuration problem. The Reverse Address Resolution Protocol (RARP) [10] (through theextensions defined in the Dynamic RARP (DRARP) [5]) explicitlyaddresses the problem of network address discovery, and includes an automatic IP address assignment mechanism. The Trivial File Transfer Protocol (TFTP) [20] provides for transport of a boot image from a boot server. The Internet Control Message Protocol (ICMP) [16]provides for informing hosts of additional routers via "ICMPredirect" messages. ICMP also can provide subnet mask information through the "ICMP mask request" message and other information through the (obsolete) "ICMP information request" message. Hosts can locate routers through the ICMP router discovery mechanism [8].BOOTP is a transport mechanism for a collection of configuration information. BOOTP is also extensible, and official extensions [17] have been defined for several configuration parameters. Morgan has proposed extensions to BOOTP for dynamic IP address assignment [15]. The Network Information Protocol (NIP), used by the Athena project at MIT, is a distributed mechanism for dynamic IP address assignment [19]. The Resource Location Protocol RLP [1] provides for location of higher level services. Sun Microsystems diskless workstations use a boot procedure that employs RARP, TFTP and an RPC mechanism called "bootparams" to deliver configuration information and operatingsystem code to diskless hosts. (Sun Microsystems, Sun Workstation and SunOS are trademarks of Sun Microsystems, Inc.) Some Sunnetworks also use DRARP and an auto-installation mechanism toautomate the configuration of new hosts in an existing network.In other related work, the path minimum transmission unit (MTU)discovery algorithm can determine the MTU of an arbitrary internet path [14]. The Address Resolution Protocol (ARP) has been proposed as a transport protocol for resource location and selection [6]. Finally, the Host Requirements RFCs [3, 4] mention specificrequirements for host reconfiguration and suggest a scenario for继续阅读。

Fortify使⽤⼿册中国建设银⾏⽹上银⾏投资产品创新项⽬F o r t i f y使⽤⼿册总⾏信息技术管理部⼴州开发中⼼2008年6⽉修改记录本⽂档中所包含的信息属于机密信息，如⽆中国建设银⾏的书⾯许可，任何⼈都⽆权复制或利⽤。

?Copy Right 2008 by China Construction Bank ⽬录1、引⾔ (5)1.1⽬的 (5)1.2背景 (5)1.3定义 (5)1.4环境说明 (6)1.5提醒注意 (6)1.6相关要求 (7)２、安装FORTIFY (7)2.1进⼊F ORTIFY安装⽬录 (7)2.2输⼊LICENSE KEY:BAHODPERE9I9 (8)2.3选择ALL U SERS (9)2.4下⾯选项全部选中 (10)2.5选择N O选项 (11)３、使⽤FORTIFY (12)3.1进⼊源码⽬录执⾏SCA COMMANDLINE S CAN.BAT (12)3.2SCA COMMANDLINE S CAN.BAT的内容 (12)４、结果查询 (12)5、可能的问题 (14)6、结果分析 (15)6.1R ACE C ONDITION (15)6.2SQL I NJECTION (16)6.3C ROSS-S ITE S CRIPTING (16)6.4S YSTEM I NFORMATION L EAK (18)6.5HTTP R ESPONSE S PLITTING (18)1、引⾔1.1⽬的提⾼中⼼项⽬软件安全意识转达总⾏关于软件安全编码及测试的相关要求了解、学习fortify SCA的使⽤1.2背景⽹银投资产品创新项⽬⽂档。

1.3定义Fortify Source Code Analysis Suite是美国Fortify Software为软件开发企业提供的软件源代码安全漏洞扫描、分析和管理的⼯具。

使⽤该⼯具能弥补软件开发⼈员、安全⼈员和管理⼈员在源代码⽅⾯的安全知识不⾜，加速代码安全审计和⽅便软件安全风险的管理。

Chapter 4EM 1110-2-1100THE COASTAL ENGINEERING MANUAL(Part I)1 August 2008 (Change 2)Table of ContentsPage I-4-1. Background..............................................................I-4-1a. Shore Protection Planning and Design, TR 4...................................I-4-1b. Shore Protection Manual, SPM..............................................I-4-1c. Coastal Engineering Manual, CEM..........................................I-4-2 I-4-2. Structure................................................................I-4-2a. Part II.................................................................I-4-2b. Part III.................................................................I-4-2c. Part IV.................................................................I-4-2d. Part V..................................................................I-4-3e. Part VI.................................................................I-4-3f. Appendix A.............................................................I-4-3g. Updates................................................................I-4-3 I-4-3. References...............................................................I-4-3 I-4-4. Acknowledgments........................................................I-4-4EM 1110-2-1100 (Part I)1 Aug 08 (Change 2) Chapter I-4The Coastal Engineering ManualI-4-1. BackgroundDuring the 1970s, ‘80s, and ‘90s, coastal engineering practice by the U.S. Army Corps of Engineers (USACE) and standard engineering for most coastal projects throughout the world have been based, wholly or in part, on the Shore Protection Manual (SPM). Since the SPM was last updated in 1984, the coastal engineering field has witnessed many technical advances and increased emphasis on computer modeling, environmental restoration, and project maintenance applications. The BEB produced the first standardized guidance on coastal structure design in 1954, Shore Protection Planning and Design, also known as TR-4. This was the forerunner of the SPM that was first published by CERC in 1973, and revised in 1975, 1977, and 1984. These documents present the methodology that guided coastal structure and beach fill design for most of the projects constructed to date. The USACE traditionally is responsible for constructing and maintaining United States Federally authorized coastal civil works projects including harbor entrance channels, navigation channels and structures, coastal storm damage reduction and shore protection projects. Therefore, the USACE is primarily responsible for developing the principles of coastal engineering as they are practiced in the United States.a.Shore Protection Planning and Design, TR 4. The methodologies of TR-4 emphasized designing coastal structures for stability against wave forces. The technology available at that time provided little means to address the functional performance of structures, nor provide any guidance for predicting the performance or stability of a beach fill. Beach and dune design was only qualitatively addressed. Simple linear wave theory, static terrestrial structural engineering principles, and trail-and-error experiential data were used to develop the empirical relationships and rules-of-thumb presented in TR-4. Beach fills of this era were not usually designed to perform a particular function, but were typically placed as an added feature to increase the sediment supply in the area of interest and to reduce wave energy striking the protective structures (the primary project feature).b.Shore Protection Manual, SPM. The SPM was a significant advancement over TR-4 in that it used the results of physical model tests to develop principles of wave-structure interaction, advancements in wave theory, and statistics and other data from various projects. The SPM provided significantly more guidance in the positioning and intent of groins and breakwaters, predicting the flood control benefits of seawalls, and predicting the stability of beach fills. At 1,160 pages, the first edition of the SPM was almost three times the length of the 20-year-older TR-4 (Camfield 1988). The SPM and beach fill projects of the 1970s and early ‘80s were designed around the objective of beach erosion control and recreational use. The quantity of material to be placed was computed based on the long-term recession rates, and the amount of surface area desired to support recreational needs. The SPM presented guidance to assist in predicting maintenance nourishment quantities based on the grain size of the placed fill and its projected stability relative to the native material grain size. Neither the SPM nor the projects constructed during this time concerned themselves with the performance of the beach fill template during a particular storm. At that time, beach fills were not usually designed with a primary purpose of providing flood control benefits.The SPM is commonly used as a university textbook and as a training aid for apprentice engineers. It is also a convenient reference for empirical procedures to compute a particular design parameter. Approximately 30,000 copies have been sold through the U.S. Government P rinting Office. Translations into other languages, including Chinese and Catalonnian (Spanish), further attest to the SPM’s role as an international standard guidance for professional coastal engineers (Pope 1993, 1998). Even though the SPM is a generalEM 1110-2-1100 (Part I)1 Aug 08 (Change 2)coastal engineering reference, some aspects of navigation and harbor design are not included and its primary focus is shore protection.c.Coastal Engineering Manual, CEM. The advent of numerical models, reliable field instrumentation techniques, and improved understandings of the physical relationships which influence coastal processes lead to more sophisticated approaches in shore protection design in the later 1980s and 90s. Numerous guidance and analytical tools have been developed over the last 15 years to assist the coastal engineer in predicting not only the stability of a beach fill, but also its performance during extreme events. Cross-shore and alongshore change models, hydrodynamic hind cast data bases, and stochastic statistical approaches have been developed to provide the practicing coastal engineer with procedures for quantifying the flood control benefits of a proposed design. The functional interaction of beach erosion control structures (i.e., groins and breakwaters) can be analyzed with numerical simulation. Seawalls can be designed not only for stability, but also physically modeled to predict various elements of the wave-structure interaction including scour and overtopping. A “modern” technical document incorporating all the tools and procedures used to plan, design, construct, and maintain coastal projects was needed. The USACE tasked the Coastal Engineering Research Center and, later, the Coastal and Hydraulics Laboratory with producing a new reference incorporating established science and much of this new technology, to be called the Coastal Engineering Manual (CEM). Included in the CEM are the basic principles of coastal processes, methods for computing planning and design parameters, and guidance on how to develop and conduct studies in support of coastal storm damage reduction, shore protection, and navigation projects. Broader coverage of all aspects of coastal engineering are provided, including new sections on navigation and harbor design, dredging and dredged material placement, structure repair and rehabilitation, wetland and low energy shore protection, cohesive shores, risk analysis, numerical simulation, the engineering process, and other topics.I-4-2. StructureThe CEM contains two major subdivisions: science-based parts and engineering-based parts. The science-based parts include “P art II - Coastal Hydrodynamics,” “P art III – Coastal Sediment P rocesses,” and “Part IV – Coastal Geology.” These provide the scientific foundation on which the engineering-based parts rely.a.Part II. “Coastal Hydrodynamics” is organized to lead the reader from the fundamental principles of linear and other wave theories, including irregular waves and spectral analysis, to ocean wave generation and through the process of transformation as the wave approaches and reacts with the coastline. Analysis of water level variations including astronomical tides and storm surges are presented along with the hydrodynamics of coastal inlets and harbors are included in other chapters.b.Part III. “Coastal Sediment Processes” includes chapters on sediment properties, along shore and cross-shore transport, as well as chapters on wind transport, cohesive sediment processes and shelf transport.c.Part IV. “Coastal Geology” includes chapters on terminology, geomorphology, and morphodynamics.The two engineering-based parts, Part V – “Coastal Project Planning and Design” and Part VI – “Design of Coastal Project Elements” are oriented toward a project-type approach, rather than the individual structure design approach that characterized the SPM. The architecture and substance of the engineering-based parts is the result of an internationally-attended workshop in February 1994. A logical systems-based approach is used for the engineering structure of the CEM. This mirrors the engineering process with guidance inEM 1110-2-1100 (Part I)1 Aug 08 (Change 2) selecting and using various planning and design tools as appropriate for the project at hand. The engineering tools are presented in a modular grouping to allow for future updates as the technology continues to advance.d.Part V. “Coastal Project Planning and Design” starts with chapters discussing the planning and design process and site characterization. Following these general chapters are ones discussing the planning and design of shore protection projects (including coastal armoring, beach restoration, beach stabilization and coastal flood protection projects), beach fill, navigation projects (including defining the fleet, entrance channel, inner harbor elements, structures, sedimentation, maintenance, and management), and environmental enhancement projects (including laws, regulations, and authorities, issues, alternative approaches, planning, and design). A final chapter outlines conditions and regulations unique to USACE projects in the United States.e.Part VI. “Design of Coastal Project Elements” includes chapters discussing philosophy of coastal structure design, the various types and function of coastal structures, site conditions, materials, design fundamentals, reliability, and the design of specific project elements (including a sloping-front structure, vertical-front structure, beach fill, floating structure, pile structure, and a pipeline and outfall structure.f.Appendix A. The “Glossary of Coastal Terminology” has been compiled from numerous sources and lists terms found throughout the CEM. Note that there is no single, comprehensive list of mathematical terms and symbols. Each CEM chapter has its own symbol list.g.Updates. The CEM is intended to be a “living document” and to be updated periodically as advances in the field render the existing chapters obsolete or inadequate. Comments and suggestions should be addressed to the Coastal and Hydraulics Laboratory, CEERD-HN-CE. Corrected or modified chapters will be posted on the CHL web page.I-4-3. ReferencesCamfield 1988Camfield, F. E. 1988. “Technology Transfer – The Shore Protection Manual,” Journal of Coastal Research, 4(3), pp 335-338.Pope 1993Pope, J. 1993. “Replacing the SPM: The Coastal Engineering Manual.” The State of the Art of Beach Nourishment, Proceedings, 6th Annual National Conference on Beach Preservation Technology, Florida Shore and Beach Preservation Association, Tallahassee, FL, pp 319-334.Pope 1998Pope, J. 1998. “Replacing the SPM: The Coastal Engineering Manual.” PIANC Bulletin, No. 97, pp 43-46. USACE 1954USACE 1954. Shore Protection Planning and Design, Technical Report No. 4, Beach Erosion Board, U.S. Government Printing Office, Washington, DC.Shore Protection Manual 1984Shore Protection Manual, 4th ed., 2 Vol., U.S. Army Engineer Waterways Experiment Station, U.S. Government Printing Office, Washington, DC, 1,088 p.EM 1110-2-1100 (Part I)1 Aug 08 (Change 2)I-4-4. AcknowledgmentsAuthors of Chapter I-4, “The Coastal Engineering Manual:”Joan Pope, U.S. Army Engineer Research and Development Center, Vicksburg, Mississippi. John H. Lockhart, Jr., Headquarters, U.S. Army Corps of Engineers, Washington, DC, (retired). Reviewer:Andrew Morang, Ph.D., CHL。

核心理念（Core idea）New curriculum itselfCore idea:(1) the "people-oriented" and "student-centered development" is the starting point of curriculum reform; (2) developed the concept of curriculum is the inevitable choice of constructing the modern curriculum system; (3) democracy is a strong foundation of constructing the new teacher-student relationship and course management system; (4) stressed the "three-dimensional target" (the integration of knowledge and skill, process and method, emotion attitude and values); (5) establish the concept of lifelong learning; (6) to establish the development evaluation and development view; (7) critique and innovation is the soul of the reform of basic education;(8) return to life is a necessary result of the new curriculum reform.2. the new curriculum of the "new": (1) the new curriculum goal of diversity, age, operation; (2) reconstruction of the new curriculum structure; (3) the curriculum standard replaces the teaching plan and syllabus; (4) emphasize the diversification of learning style, self advocacy, cooperation, inquiry learning, research the reform of classroom teaching; (5); (6) advocate for the future, to evaluate the development objectives of the concept; (7) the implementation of three level curriculum management (national, local, school); (8) pay attention to teachers' understanding and participation; (9) put forward the "stand after the first break, the first experiment after the promotion the working principle of.1., the scientific and progressive structure of curriculum.The serious problems existing in the course structure of China's basic education curriculum: the dominant proportion of specific subjects, the course content by imbalance, troublesome old side. The curriculum reform attempts to achieve the comprehensiveness, balance and selectivity of the basic curriculum structure. The details are as follows: (1) the construction of curriculum education type diversification, presented in a comprehensive division in two ways, such as comprehensive courses in art, morality and life, comprehensive practical activities; (2) to construct subjects with balanced structure; (3) improve the optimization course content, first delete the abstruse, obscure, old the second thing, the increase in students and life related components, again to achieve hierarchical curriculum standard. In a word, the adjustment and transformation of curriculum structure is an extremely important and arduous task.2., the essence of integrated practice curriculumSet up comprehensive practice activities from primary school to senior high school and take compulsory courses. It includes information technology education, research learning, community service and social practice, labor and technical education. It takes students' experience and life as the core, and it has the following characteristics: (1) integrity. Based on the whole of human personality, it is based on the sound development of each student; (2) practicality. On the basis of students' real life and social practice, students' practicalability and creative ability are developed; (3) openness. For each student's personality development, respect for the special needs of each student's development; (4) generative. Each activity is an organic whole, with activity, new goals, and new themes evolving. Cognitive experience is not deepened; creative sparks continue to emerge; (5) autonomy. Respect the students' interests, choose the purpose, the content, the way, and guide the teacher to decide the form of the result.3. curriculum goal presentation techniques:(1) the objectives of the course are hierarchical and take Chinese as an example:Education (or purpose) nine year compulsory education curriculum objectives, Chinese curriculum objectives, grades 1 - 2, academic objectives, reading objectives, teaching objectives(2) two basic behaviors: the statement of objectives the objectives (way of "knowledge and skills"); experience or performance goal way (for "process and method" and "emotional attitude and values")(3) the basic elements of behavior goal statement: behavior subject, verb, condition and degree of performance.(4) the subject of behavior should be students, not teachers.(5) act verbs are as comprehensible and measurable as possible.(6) necessary to attach the conditions to the outcome of the goal.(7) to have a specific degree of performance. (never make students, improve students, train students...)4. teaching is the activity of "communication" and "cooperation"Without communication, there can be no teaching",The teaching of losing communication is unimaginable. Teaching is a collective, high density, multi structural communication activity. Teaching is a multiple network relationship, human communication and cooperation are language oriented media, and all subjects are language teaching. Teaching is the creation process of language, culture and communication culture, as well as the basic process of each student's academic ability growth and personality growth.5., the concept of effective teaching:"Effectiveness" means whether students have progress and development, and that teaching is the only indicator of effectiveness. Whether teaching benefits or not means whether the students have learned anything or whether the students are good at it. "Teaching" refers to all behaviors that teachers cause, maintain or promote students to learn. Teaching is what students want to learn, why they know, or what degree they learn. Students are easy to understand, and they are the real teaching.The concept of effective teaching contents: (1) pay attention to the students' progress or development, teachers determine the "all is for the development of students" thinking, a concept of "whole person"; (2) pay attention to the effectiveness of teaching, teachers should have the concept of time and efficiency; (3) more attention to the estimation; (4) teachers need to have a kind of consciousness. Teachers reflect on their daily teaching behavior, and continue to ask, "what kind of teaching is effective?"" "Is my teaching effective?"" "Is there any more effective teaching than I do?"" (5) effective teaching is also a set of strategies. The act of solving a problem6. effective teaching strategies: (1) teaching preparation strategy: what teachers should do when designing teaching plans. The main teaching objectives of writing, for processing materials, choose the main teaching behavior, compiling teaching organization form, teaching plan; (2) the implementation of teaching strategies: the main teaching behavior, teaching behavior, classroom management behavior, design their own personalized teaching, creating unique teaching style; (3) teaching evaluation strategy. Evaluation runs through the whole teaching activity. It is divided into the evaluation of students' achievement and the evaluation of teachers' teaching professional activities. The evaluation of examination and test th.7., the teaching meaning of the theory of multiple intelligences: creating conditions for the implementation of individualized teaching. (1) understand the students: the students how to learn the data collection, the establishment of student information exchange school library effectively("portfolio"), a common way of learning or students' cooperative and complementary learning style; (2) in the study or research project: Intelligence display, project. (the student intelligence characteristic, work quality, communication, teachers and students together, reflection) to multiple intelligence theory as the guide to provide good ideas with personalized teaching ideas and teaching methods of optimal for the effective implementation of quality education in our country.8. understand education and life"(1) the process of education is also the life process of teachers and students. Education is a part of individual life course inseparable; (2) the life education contains abundant factors; students outside the school life is an important field of school curriculum resources development; (3) the life is realistic, specific human life, education must be based on the life of the students, care for students' life development. Committed to the integrity of people; (4) education is different from the life, education can not be separated from will not restore the lives of students, education must be higher than life, content and activities of education is the distillation of life and life beyond.9. new curriculum needs the teaching idea: (1) conformity teaching and curriculum. Students and teachers participate in the curriculum development, and the teaching process is the process of continuous generation and transformation of curriculum content and the continuous construction and promotion of curriculum meaning. Teaching and curriculumtransform and promote each other organically, and (2) emphasize interactive teacher-student relationship. The teaching process is a process of teacher-student interaction, active interaction and common development. The relationship between teachers and students is the human equality, two-way, understanding of the relationship is humane, harmonious, democratic, equal, mutual communication between teachers and students interactive teaching; (3) constructing the target system of the quality of education classroom teaching: unity, structure and process of understanding and friendship; (4) to build a the vitality of the classroom teaching system; (5) to change the learning style of students.(independent innovation, inquiry learning)10., education, as a cultural psychological process, is concerned with the formation and development of ideal individuals. There are two basic points of view:(1): the value guidance of education has the direction and goals (all the educational activities are carried out to achieve the purpose of Education); moral responsibility teachers for students, education is a projection, contains the subjective interest of educators to guide activities.(2): refers to the self construction of the educated spiritual world is independently and dynamically generated construction, rather than external forces shaping, through activities and self construction, individual creativity, to characterize the potential. Coagulation during activity or activity. Through the activity, it also enriches and develops individualpotential, quality and accomplishment.In a word, this kind of education, students get the potential development and spiritual awakening, heart bright, unique manifestation of the subjectivity of teachers and students; experience sharing, fusion of horizons, inspired by the soul.11., why should we advocate independence, cooperation and inquiry learning?(1) from the perspective of education as a cultural psychological process, education should pay attention to the formation and development of ideal individuals (see 10 questions); (2) respect for students based on respect for students means respecting the needs of students. Students need inquiry, new experiences, recognition and appreciation, and the need for responsibility. These needs provide the basis for promoting inquiry learning in education; (3) the harvest includes not only cognitive aspects, but also attitudes, values, enrichment and promotion. Effective teaching, it must be indispensable for students' autonomy, cooperation and inquiry learning.12. how to implement autonomous, cooperative and inquiry learning in the classroom?(1) make clear the responsibilities of teachers, help students to test and reflect on themselves, find, collect and utilize resources, design appropriate learning activities, and discover the personal meanings of what they learn;(2) to develop and provide adequate curriculum resources;(3) to establish a new view of teaching.A. can help students make sure to reach the goal ofB. teaching service for students' learningC. closely related to students' life worldD. motivate students to complete challenging taskE. timely feedback, bridge constructionF. do not restrict students to think about the direction ofG.H. to help students find personal meaning of knowledge emphasizes understanding instead of memorizing the conclusionI. often indicates the relationship betweenJ. course and other courses to guide students to create a harmonious learning atmosphereK. teachers must have the courage to admit their mistakes or missing. (teachers and students grow together)13., "in which situations do students learn best?""(1) when the students are interested in; (2) when the students in the best physical and mental state; (3) when the teaching content can use various forms to show; (4) when students encountered intellectual challenges; (5) when the students found the personal meaning of knowledge; (6) when the students to participate in its own exploration and innovation; (7) when students are encouraged and trust can do important things; (8) when the students have more self expectations; (9) when the students can apply their knowledge; (10) when the students are full of trust and love of the teachers. They learn best.14. teachers: (1) exam grades and exams of learning (2) knowledge and skills (3) knowledge and skills and emotionalattitude (4) students' lifelong learning desire and ability (5) the needs of the students (6) students personalized learning (7) learner autonomy (8 the dignity of students)The basic concept of 15. developmental curriculum evaluation: (1) evaluation is important process in parallel with the teaching process, every link in teaching activities; (2) evaluation is provided powerful information, insight and guidance, to promote development; (3) the evaluation should embody the people-oriented ideology, construction the development of the individual, specific ideas: the interaction of evaluation objects (evaluation) and the diversity of evaluation contents (not only concerned about the results, but also on the ability of innovation and practice, etc.) the evaluation process of dynamic (about the result, especially,Growth record bag16., the basic content of development curriculum evaluation is to promote the development evaluation system of students, teachers and schools.。

Static and dynamic behavior of concrete andgranite in tension with damageJ.T.Gomez a ,A.Shukla b,*,A.Sharma baCode 8232,Naval Undersea Warfare Center,Newport,RI 02841,USAbDynamic Photomechanics Laboratory,Department of Mechanical Engineering and Applied Mechanics,University of Rhode Island,92Upper College Rd.,Wales Hall,Kingston,RI 02881-0805,USAAbstractA series of dynamic and static tensile-splitting experiments were performed on concrete and granite specimens to investigate the e ect of induced damage on their tensile strength.These experiments were performed as part of a larger e ort investigating the penetration process into the two materials.The strain rate each specimen was subjected to remained constant for these experiments,while the level of induced damage was increased.Damage was induced into the specimens through repeated drop-weight impacts and quanti®ed using a statistical technique.The dynamic splitting experiments were performed using a split Hopkinson pressure bar (SHPB),while the static splitting experiments were conducted per the ASTM standard procedures D3967and C496.As part of the investigation,photoelastic dynamic tensile-splitting experiments were also performed to establish the validity of using static relations for the determination of dynamic tensile strength.The experiments showed that the static splitting strength was highly dependent on the orientation of the induced damage with regard to the applied loading;however the dynamic tensile strength decreased with increasing damage with no apparent dependency on the random damage orientation.Photoelastic experiments have shown that the mechanism of failure changes for the dynamically tested damaged specimens,reducing their de-pendence on damage orientation.Ó2001Elsevier Science Ltd.All rights reserved.1.IntroductionThis experimental study of the dynamic be-havior of concrete and granite with induced damage is a portion of a larger study into the multiple impact penetration of these materials.During the penetration process caused by multiple impacts,damage is accumulated in the region around the impact zone.The strength of cementedmaterials is a function of the inherent ¯aws present throughout the materials [1].By inducing damage into a material,the inherent ¯aws will grow in size and number,and the strength should decrease.Therefore,it becomes important to understand the e ect of damage on dynamic material strength in the study of multiple impact penetration.To study the e ect of induced damage on the strength of the G-mix Air Force concrete and Barre granite materials,whose properties are shown in Table 1,damage was induced into the specimens by repeatedly dropping a weight onto the face of each specimen.The amount of specimen damage was quanti®ed by a measure of the crack surface area created by thedamage.Theoretical and Applied Fracture Mechanics 36(2001)37±49/locate/tafmec*Corresponding author.Tel.:+1-401-874-2283;fax:+1-401-874-2950.E-mail addresses:gomezjt@ (J.T.Go-mez),shuklaa@ (A.Shukla),sharmaa@ (A.Sharma).0167-8442/01/$-see front matter Ó2001Elsevier Science Ltd.All rights reserved.PII:S 0167-8442(01)00054-4Photographs of the specimens were taken before and after the damage was induced.A grid of test lines was superimposed on the damaged specimen photograph,and the intercepts of the visible cracks with the grid lines were counted.The crack surface area per specimen volume was calculated using a statistical microscopy technique[2].The quasi-static tensile-splitting strengths of the damaged and undamaged specimens were deter-mined using ASTM standard procedures for both the concrete and granite specimens.To determine the dynamic tensile-splitting strength as a function of damage,a split Hopkin-son pressure bar(SHPB)was used to load the specimens diametrically with a dynamic stress wave.For these experiments it is assumed that the peak tensile-splitting stress of the specimen can be calculated from the peak transmitted compressive strain measured in the transmitter bar using the static relationshipfor sp litting stress,which is a function of load and specimen geometry[3].To ensure the validity of this assumption,photoelastic dynamic tensile-splitting experiments were per-formed on brittle,transparent polymer discs made of Homalite-100.The photoelastic experiments showed that the specimens were in equilibrium,i.e.the opposing contact loads were equal,for a relatively long pe-riod of time prior to failure.Also the experiments determined that once in equilibrium,the dynamic stress®eld in the specimen is identical to the stress ®eld in a statically loaded specimen.The experimental results showed that both the concrete and granite static tensile-splitting strength randomly decreased as the damage was increased, and in some cases remained unchanged in highly damaged specimens.In contrast,the dynamic ten-sile-splitting strength of the concrete and granite decreased in an orderly manner as the level of damage was increased.These results are due to the random orientation of the specimen in the loading apparatus.The static splitting strength was highly dependent on the damage orientation while the dynamic splitting strength was not.Photoelastic dynamic splitting experiments using damaged Ho-malite-100specimens determined that the failure mechanism of the damaged specimens changed, reducing their dependence on damage orientation as compared to statically tested specimens.2.Experimental procedure2.1.Quasi-static tensile-splitting experiments ASTM standard Brazilian,or tensile-splitting, experiments are usually performed on concrete or rock[4,5].For these types of materials it is di cult to fabricate and test typical``dog bone''speci-mens.The Brazilian tensile test was developed in order to indirectly determine the tensile strength of brittle materials using cylindrical specimens.Based on elasticity theory,the two-dimensional stress ®eld in the disc can be derived and then simpli®ed to examine only the stress along the loading line [6].Taking into account the specimen thickness,L, the stress distribution for the Brazilian splittingTable1Properties and composition of G-mix concrete and Barre graniteMaterial G-mix concrete Barre granite Compressive strength(MPa)41172.0Splitting tensile strength(MPa) 3.19.4Density(kg/m3)23372619 Composition Mixture for one cubic yard(kg)Mineral content(%)757.53/8-4Limestone36.5Plagioclase592.4Concrete sand31.9Quartz164.7Portland cement,type117.8Potash feldspar108.9Class``F''¯y ash8.0Biotite164.7Water 3.0Muscovite2.8Granophyre38J.T.Gomez et al./Theoretical and Applied Fracture Mechanics36(2001)37±49test is given by Eqs.(1),with parameters de®ned in Fig.1[1]:r x 2P p LD ;r y 2P p LD D 2y D Ày À1: 1 As shown,a constant tensile stress,r x ,is gener-ated along the loading line.At the contact points the elasticity solution is no longer valid due to the singularity of the loading.At these points there exists a bi-axial compressive stress of equivalent levels,which,along with the bearing blocks used to apply the load,allow the specimen to fail in tension along the loading line and not locally by compres-sion.Brittle materials,with a relatively low tensile strength compared to their compressive strength,will tend to fail in tension along the loading line.For each of the splitting tensile experiments the maximum load,P ,was used to calculate the split-ting stress,r x ,at failure using the ®rst of Eqs.(1).2.2.Split Hopkinson pressure bar for tensile-splitting In order to perform tensile splitting experiments under dynamic loading,an SHPB was used in compression.However,instead of sandwiching the specimen lengthwise,the specimen was held dia-metrically between the bars using steel bearing bars to avoid local failure due to the point load (Fig.2).To load the specimen,the incident bar is impacted with a projectile ®red from a gas gun,which creates a compressive wave traveling down the bar.At the specimen,this wave will be partially re¯ected back into the incident bar and partially transmitted into the transmitter bar.Strain gages mounted at the mid points of both bars are used to record the strain waves.Assuming one-dimen-sional propagation,and negligible attenuation of the waves,the loads on each end of the specimen can be calculated as a function of time with Eqs.(2)[7]:P 1 A b E b e i e r ;P 2 A b E b e t ;2where P 1and P 2are the loads on the incident and transmitted bar contact faces,respectively,A b is the bar cross-sectional area,E b is the Young's modulus of the bar material,and e i ,e r ,e t are the incident,re¯ected,and transmitted strain pulses shifted in time to account for the mid-bar location of the strain gages.For specimens in compression,the SHPB analysis assumes that the load on each specimen face is equal,so that the specimen is in equilib-rium.With this assumption the specimen stress/strain response can be calculated [7].However,for the dynamic splitting experiment the standard analysis to obtain the specimen stress can no longer be used.For these experiments it has been assumed that the peak tensile-splitting stress of the specimen is proportional to the peak transmitted compressive strain measured in the transmitter bar by the ®rst of Eqs.(1)[3],and that the load P is now de®ned by the second of Eqs.(2).For all these experiments,a 50.8mm diameter SHPB and 406.4mm long projectile were used.The concrete specimens wereapproximatelyJ.T.Gomez et al./Theoretical and Applied Fracture Mechanics 36(2001)37±493950.8mm in diameter and 21.8mm long.The granite specimens were approximately 55.1mm in diameter and 31.8mm long.Fig.3shows an un-damaged face for both the granite and concrete specimens.2.3.Photoelastic dynamic tensile-splitting experi-mentsPhotoelastic dynamic tensile-splitting experi-ments were performed on a brittle transparent material,Homalite-100,to determine the validity of using the static relations for dynamically loaded specimens (Fig.4).For the static relation to be valid,the specimen must be in equilibrium,i.e.the opposing contact loads must be equal.In similar experiments involving dynamic wave propagation in a chain of discs,it was shown that if the loading pulse width is much longer than the disc diameter,quasi-static stress ®eld equations were valid in a region close to the contact point [8].For the SHPB dynamic loading in this study,the incident pulse length is related to the projectile length.Therefore,all the photoelastic experiments were performed on a 12.7mm SHPB using a 203mm long projectile,giving a strain pulse of approximately 406mm in length.The gas gun pressure was initially varied from 0.207to 0.414MPa to deter-mine the pressure required to obtain fracture in the specimen.The specimens for all the dynamic splitting experiments were Homalite-100discs,25.4mm in diameter and 6.4mmthick.Fig.3.Undamaged G-mix concrete and Barre granitespecimens.40J.T.Gomez et al./Theoretical and Applied Fracture Mechanics 36(2001)37±492.4.Induced damage application and quanti®cation The concrete and granite specimens were tested both statically and dynamically as discussed earlier with increasing levels of induced damage.To in-duce damage in the specimens,a steel weight was dropped through a vented plastic tube,onto the specimen face.Each specimen was hit with multi-ple impacts until cracks were visible in the speci-men face.The amount of specimen damage was quanti-®ed by a measure of the crack surface area created by the damage.Photographs of the specimens were taken before and after the damage was induced.A grid of test lines was superimposed on the dam-aged specimen photograph,and the intercepts of the visible cracks with the grid lines were counted.A photograph of the grid lines being used to count the intercepts is shown in Fig.5.The crack surface area per specimen volume,S v ,is proportional to the number of intercepts by S v2N L ts2 number of interceptstest line length: 3The intercepts are counted as shown in Fig.5,and the test line length can be calculated as the lengthof grid lines that lie over the circular specimen.Forexample,for a 50mm diameter specimen the sys-tem of grid lines has a length of 1.014m.For the 46intercepts shown,the damage induced in the specimen would be 90.73m 2=m 3.This method was originally developed as a microscopy technique to study the ¯aws and grain boundaries of metal samples [2].For all the experiments,static and dynamic,no particular specimen orientation of the damage to the loading line was desired.The specimens were randomly oriented between the loading contacts.3.Results and discussion 3.1.Specimen equilibriumThe photoelastic experiments determined that,by subjecting the splitting specimen to a relatively long dynamic loading pulse in the SHPB,the specimen reaches equilibrium quickly and remains in equilibrium until fracture occurs.As shown (Fig.6),the wave front enters the specimen,loading only the incident contact (0l s).Both contact points of the specimen begin to be loaded when the wave travels across the specimen (10l s).When the contact loads become equal (30l s)the specimen is in equilibrium,and the photoelastic fringe patterns appear identical to a statically loaded specimen (Fig.7).These photoelastic fringe patterns are lines of constant maximum shear stress,and can be used to determine the stress ®elds in the specimens [9].Once the specimen is in equilibrium,the stress ®eld re¯ects back and forth increasing in magni-tude,as evident by the fringe patterns becoming more dense (50l s,Fig.6).The specimen remains in equilibrium until the time of failure (93l s).With this,the static stress relationship(Eqs.(1))is valid to determine the dynamic splitting strength of a specimen loaded in a SHPB with a relatively long projectile [10].3.2.Static tensile-splitting resultsAs shown,the static splitting strength of both the concrete (Fig.8)and the granite (Fig.9)asaFig.5.Grid lines superimposed over damaged specimen with intercepts highlighted.J.T.Gomez et al./Theoretical and Applied Fracture Mechanics 36(2001)37±4941function of damage randomly decreases to about half its virgin strength as the damage increases.However,in some cases the material retained its full strength even though the specimen was highly damaged.This is a result of the slowly developing stress ®eld being dependent on the damage orientation with respect to the loading line.As mentioned,the tensile-splitting test develops a constant tensile stress down the loading line of the specimen.If the damage cracks were parallel to the loading line,they would greatly decrease the strength.How-ever,if the damage cracks were perpendicular to the loading line,the cracks would close under thecompression in the y -direction and not a ect the splitting strength.This dependency on random damage orientation is evident in the static splitting results.3.3.Dynamic tensile-splitting resultsAs shown,the dynamic splitting strength for both the concrete (Fig.10)and the granite (Fig.11)decrease in an orderly fashion with increasing damage.This result shows that the random ori-entation of damage cracks in the specimens does not a ect the dynamic splitting strength as it did in the staticexperiments.Fig.6.Homalite-100specimen in dynamic tensile-splitting experiment.42J.T.Gomez et al./Theoretical and Applied Fracture Mechanics 36(2001)37±494.Photoelastic dynamic splitting experiments with damaged specimensTo examine the di erence between the static and dynamic splitting experiments with induced damage,a series of photoelastic dynamic splitting experiments was conducted using damaged Ho-malite-100specimens.The specimens,identical to the ones used previously in the equilibrium ex-periments,had a central crack initiated by tappinga short razor blade against the face.The amount of damage the cracks represented was quanti®ed using the method outlined earlier,and found to be approximately the same for each specimen.The projectile length and ®ring pressure also remained consistent with the earlier experiments.Four ad-ditional experiments were performed,two with the central crack parallel to the loading line,one with the crack oriented at an angle of 45°to the loading line,and one with the crack perpendicular to the loading line.The dynamic splitting strength of the Homa-lite-100,at an average strain rate of 200/s,dropped from 1.5times the static strengthforFig.7.Static Homalite-100tensile-splitting fringepattern.J.T.Gomez et al./Theoretical and Applied Fracture Mechanics 36(2001)37±4943the undamaged specimens to0.85times with the induced damage,with no orientation depen-dence.To examine the failure mechanisms of the un-damaged and damaged specimens the high-speed photography used to capture the fringe patterns was also used to examine crack propagation and specimen failure.Fig.12shows the typical failure of an undamaged dynamic splitting specimen made of Homalite-100.As shown,the splitting cracks form just outside a dark region near the contact point at approximately93l s from the initial specimen loading.Depending on the loading level one or more of the cracks propagate across the specimen causing failure.The dark regions at the loading points were found to be in-plane cracks that formed in the area of high compression stress near the contacts.These cracks tended to curve toward the surface and not cause the speci-men to fail.The crack initiation at the incident end of the specimen agrees with the experimental and numerical work performed on concrete by Tedesco et al.[11].Examining the failure of the0°damaged specimen(Fig.13),a change in the failure mechanism is evident.The central crack is unaf-fected by the initial passing of the wave front (10l s).However as the wave re¯ects back into the specimen creating the splitting stress®eld, stress concentration at the crack tips is evident with the formation of higher-order fringes(20l s). With the increased stress at the tip,the crack grows from each end of the damage toward the contact points(30l s).Once the cracks have reached the contact point the specimen has failed. Since the dynamic loading is still being applied, additional splitting cracks form at the contacts and travel through the specimen(70l s).The failure event in this case occurs in a much shorter period of time than the undamaged case,where the cracks were just beginning to form90l s after the initial loading.The splitting experiment performed with the central crack at45°to the loading line showed a similar failure pattern(Fig.14).The compressive wave front passes through the damaged area with no real e ect(10l s)until it re¯ects from the transmitter end and the tensile stress®eld begins to form.At this point we see fringe patterns around the crack tip,indicating an increase in stress (20l s).Again the cracks propagate from either side of the damage;however in this case the cracks are shown to move toward the contact points along the highest area of tensile stress(40l s).As with the0°damaged specimen,the dynamic loading is still being applied to the specimen,so once the cracks reach the contact points,addi-tional splitting cracks form(50l s).For the last experiment,the damaged specimen was placed in the SHPB to orient its central crack perpendicular to the loading line.In this con®g-uration it would be expected that the compressive stress in the specimen would cause the crack to close,and not lower the splitting strength.This is what caused the random changes in splitting strengths observed with the statically tested specimens.However,the photoelastic experiment showed that,similar to the other pre-damaged specimens,the crack initiation site was moved from the specimen incident end to the crack tips of the induced damage.Fig.15shows the crack propagation in the specimen.The wave enters the specimen and appears una ected by the damage, even after the initial re¯ection with no formation of fringes at the crack tips(0±20l s).After the next wave re¯ection,cracks can be seen initiating at the ends of the damage(40l s)and propagat-ing toward the contact points(50±60l s).Aswith 44J.T.Gomez et al./Theoretical and Applied Fracture Mechanics36(2001)37±49the other damaged specimens,failure occurs much earlier than in the undamaged specimens,where crack initiation occurs at approximately 93l s.5.ConclusionThe static and dynamic tensile-splitting exper-iments performed determined the e ect of induced levels of damage on the splitting strength of concrete and granite specimens.The static ex-periments showed that the splitting strength is highly dependent on the orientation of the dam-age with respect to the loading line.Damage cracks perpendicular to the loading line tend to be closed by the compressive stress in that direc-tion and do not e ect the strength.Damage cracks parallel to the loading line are opened by the tensile-splitting stress and decrease the strength drastically.Therefore,by randomly ori-enting the specimens in the testing machine,some specimens that were highly damaged may still have exhibited full strength if the major portion of its damage was oriented perpendicular to the loading line.In the dynamic case,the photoelastic experi-ments determined that the specimens wereinFig.12.Crack propagation of undamaged Homalite-100specimen subjected to dynamic splitting load in SHPB.J.T.Gomez et al./Theoretical and Applied Fracture Mechanics 36(2001)37±4945Fig.13.Crack propagation of damaged Homalite-100specimen with 0°central crack subjected to dynamic splitting load in SHPB.46J.T.Gomez et al./Theoretical and Applied Fracture Mechanics 36(2001)37±49equilibrium,and the dynamic stress ®eld resem-bled the static stress ®eld.This allows the use of the static stress ®eld relation to calculate the dy-namic splitting strength.For the concrete and granite specimens,the dynamic splitting strength was shown to decrease in a regular fashion with increasing damage without a dependency on the damage orientation.Additional photoelastic experiments were per-formed with damaged specimens containing a central crack,oriented at di erent angles to the loading line,parallel,45°,and perpendicular.The dynamic splitting strength of damaged specimens at an average strain rate of 200/s,dropped from 1.5times the static strength for the undamaged specimens to 0.85times with the induced dam-age,with no orientation dependence.The high-speed images of the specimen failure showed that in all cases the crack initiation moved from the incident end of the specimen to the edges of the specimen damage.The cracks then propagated along the line of maximum tensile stress toward the contact points.Crack initiation and specimen failure in the damaged specimens were also shown to occur in approximately 50l s,where the undamaged specimens experience crack initi-ation after 93l s.In the dynamic splitting experiments,the load in the specimen increases over time as the wave re¯ects back and forth [10].Since crack initiation and failure occur in a shorter period of time with the damaged specimens,there is less time for the load to increase.The calculated splitting stress,being a function of the load recorded in the transmitter bar,is therefore lower with more in-duced damage regardless of damageorientation.Fig.14.Crack propagation of damaged Homalite-100specimen with 45°central crack subjected to dynamic splitting load in SHPB.J.T.Gomez et al./Theoretical and Applied Fracture Mechanics 36(2001)37±4947。

Contents Chapter 1 Transportation System Introduction1.1Transportation system1.1.1The statue of Transportation1.1.2The definition of Transportation system1.2Modes of Transportation1.2.1Main means of Transportation1.2.2The choice of the mode of Transportation1.3Transportation Planning1.3.1The definition of Transportation Planning1.3.2The role of Transportation Planning1.4Transportation-Related problems and Sustainability1.4.1Transportation-Related problems1.4.2Transportation and SustainabilityChapter 2 Road Transportation2.1 Road Vehicles2.1.1 Engine2.1.2 Chassis2.1.3 Body part2.1.4 Electronic control system2.2 Road transport management2.2.1 Speed Limits on Roads2.2.2 Quality management in transport2.3 Road traffic safety2.3.1 Classification of Injuries in Accident2.3.2 Protection for driver2.3.3 Protection for Motorcyclists and Cyclists2.3.4 Protection for the Pedestrian2.4 Road transport vehicles and the Requirement2.4.1 The Requirement of the Vehicle2.4.2 Vehicle dimensionsChapter 3 Rail Transport System3.1 Public Transportation3.1.1 Overview of Public Transportation3.1.2 How Flying Cars Will Work3.2 Maglev Train3.2.1 Maglev Train3.2.2 Maglevs: The Future of Flying Trains3.3 High-speed Rail3.3.1 Introduction to High-speed Rail3.3.2 All Aboard: High-speed Rail Network Connecting China3.3.3 Train Control System for High-peed Train3.4 Rapid Transit3.4.1 Introduction to Rapid Transit3.4.2 Rapid Transit Technology3.4.3 Metro Signalling3.5 Urban Rail Transport System3.5.1 Light Rail Transit3.5.2 Monorail3.6 Train3.6.1 Introduction to Train3.6.2 Train Station3.6.3 Railroad CarChapter 4 Public transit4.1 Transit in North America4.1.1 Role of Transit4.1.2 Dominance of Large Systems4.1.3 Statistics4.2 Bus Transit4.2.1 Service Types4.2.2 Operating Environments4.2.3 Vehicle Types4.2.4 Observed Bus and Passenger Flows4.3 Bus Rapid Transit4.3.1 What is BRT?4.3.2 Running Ways4.4 Public Transport Priority4.4.1 Design objectives4.4.2 Bus Priority Measures4.4.3 Bus priority treatmentsReading materialChapter 5 Logistics Engineering5.1 The General Introduction to Logistics5.1.1 What is logistics?5.1.2 The importance of Logistics5.1.3 Main activities of logistics system5.2 Introduction to Supply Chain Management5.2.1 Elements of the Supply Chain5.2.2 Supply Chain Management5.2.3 Supply Chain Management Technology5.3 RFID and the Supply Chain: Measured progress5.3.1 Starting Small5.3.2 The Last Few Inches5.4 What is Kanban?5.4.1 The Effect of Bottlenecks5.4.2 Kanban Reveals Bottlenecks Dynamically5.4.3 Worked Example5.4.4 How to Get Started with Kanban5.5 Refreshing Your Logistics Network: 6 Steps to Success5.5.1 State Your Goals5.5.2 Assemble the Data5.5.3 Clean up the Data5.5.4 Create scenarios5.5.5 Run the Models5.5.6 Make it Happen5.5.7 Expert Advice5.6 Reverse Logistics5.6.1 Helping the Customer5.6.2 Warehouse Operations5.6.3 RecyclingReferencesChapter 1 Transportation System Introduction1.1 Transportation system1.1.1 The statue of TransportationThe importance of transportation in world development is multidimensional. For example; one of the basic functions of transportation is to link residence with employment and producers of goods with their users. From a wider viewpoint, transportation facilities provide the options for work, shopping, and recreation, and give access to health, education, and other amenities. Nearly every day, items in the news remind us of transportation’s vital role in our economy and its significant relationship to our quality of life. Mobility is important to the whole community. An exploration of the realm of transportation, with emphasis on key aspects of its engineering and its close relationship to our social and economic lives is focused in this course, which is likely to be helpful to lead to transportation engineering solutions in the real world.Considering your furniture, your clothes, the food you eat, and everything else you use as part of your life, there is very little among those things that did not at some point undergo movement by at least one freight carrier.Good transportation provides for the safe, rapid, comfortable, convenient, economical, and environmentally compatible movement of people and goods. The field of transportation can be compared to a mansion with several stories, many chambers, and scores of connections. We would like to take the reader on a short tour of this mansion just to acquaint him or her with some of its characteristics. One of the prerequisites for accompanying us on this trip is to have an open mind; almost everyone will have had several years of personal experience as a user of the transportation system, such as a car driver, a bus passenger, an elevator user, a frequent flyer, or just a sidewalk user. Naturally, almost every person will tend to acquire his or her own personal viewpoint. No two persons can expect to come to the same conclusion about a problem confronting transportation even though they are each known to be highly objective and rational. Try as hard as you can to approach the field of transportation and its myriad problems with an open mind, free of presumptions and prejudice. Like food, shelter, clothing, and security, transportation is an integral part of human culture. Movement in a broad sense offers inherent joy and pleasure as well as pain, suffering, and frustration. These factors will assume even greater importance in the years ahead.Everybody is involved with transportation in so great a variety of ways that a mere listing of these ways would take us by surprise. Ultimately, all human beings are interacting over distance and time, and this interaction in itself creates involvement. Transportation has an increasinglyclose relationship to various social, economic, and political affairs. The role of transportation in the day-to-day life of human beings can be appreciated in various aspects.Historical of transportationThe principles of transportation engineering have been evolving over many millennia. Human beings are known to have laid out and used convenient routes as early as 30,000 B.C. Although it was traders and migrants who opened up most major routes of communication, the military has generally been responsible for improving the status of early routes built by civilians. The first wheeled military vehicles were developed around 2500 B.C., and since then, vehicles were developed around 2500 B.C., and since then, significant resources have been devoted by rulers and their builders to constructing and maintaining communication routes in the form of roads.Steady progress has since been maintained in providing the highway and street network (which forms the stationary component of the transportation system), in providing vehicles for moving people and goods over this network (which comprises the dynamic part), and in enhancing the ability of drivers (or controllers) to operate the vehicles Basically it is these three major interacting components that are to be studied critically.Before bicycles and motor vehicles came into fashion, vehicle speeds seldom exceeded 10 miles per hour (mph). Naturally, a surface of compacted broken stone made an ideal pavement surface, even for the solid iron wheels then in use. Today, the highway system consists of millions upon millions miles of high-class streets and highways, classified by function, into a series of interconnected networks, which provides access to most part of the world by road. The centerpiece of the highway development program in the developed countries is the freeway system, considered to be one of the greatest public works achievements since the dawn of history. In urban areas, the thrust has been in constructing complicated freeway interchanges, pedestrian and bicycle facilities and high-occupancy vehicle and bus lanes.Vehicles (and pseudo vehicles) have been in use since human beings learned to walk. People who traveled on foot could manage between 10 and 25 miles per day. It is Claimed that the Incas were able to transmit messages at the rate of 250 miles per day by using fast runners over short stretches, thus achieving speeds of about 10 mph. Horses, on the other hand, could make a1most 40miles per day, by the late 1840s, the horse-drawn street car appeared in a number of cities, operating at an average speed of about 4 mph. It was not until the 1880s that electrically propelled transportation was introduced. By the beginning of World War I, the electric street car had already had a major impact on the growth and structure of the city.The entire picture for transportation changed in 1885 with Daimler and Benz's introduction of the gasoline-powered internal-combustion engine. Within the last 100 years the motor vehicle has revolutionized private transportation all over the world. Before the appearance of the motor vehicle, vehicle speeds seldom exceeded 10 mph. The car soon changed the situation, and for purposes of safety and efficiency, traffic signals were introduced at intersections.Some of the most outstanding technological developments in transportation have occurred in the preceding 200 years:(1) The first pipelines in the United States were introduced in 1861.(2) First railroad opened in 1825.(3) The internal-combustion engine was invented in 1866.(4) The first automobile was produced in 1886 (by Daimler and Benz).(5) The Wright brothers flew the first heavier-than-air machine in 1903.(6) The first diesel electric locomotive was introduced in 1921.(7) Lindbergh flew over the Atlantic Ocean to Europe in 1927.(8) The first diesel engine buses were used in 1938.(9) The first limited-access highway in the United States (the Pennsylvania Turn-pike) opened 1940.(10) The Interstate Highway system was initiated in 1950.(11) The first commercial jet appeared in 1958.(12) Astronauts landed on the moon in 1969.(13) The use of computers and automation in transportation grew dramatically through the 1960s and 1970s and continues to grow unabated.(14) Microcomputers have revolutionized our capabilities to run programs since the 1980s and such capabilities have helped us to examine alternatives quickly and efficiently.1.1.2 The Definition of Transportation SystemTransportation is typically system engineering, A system is a set of interrelated parts, called components that perform a number of functions in order to achieve common goals. It is also, as explained at Longman Dictionary of Contemporary English, a group of related parts which work together forming a whole. Transportation is also ordinarily defined as a means of conveyance or travel from one place to another, or, it is a public conveyance of passengers or goods especially as a commercial enterprise. Transportation is everything involved in moving either the person or goods from the origin to the destination. Consider the businessman’s trip depicted in Figure1.1.The trip is from the bus inessman’s home (origin) to a hotel in a distant trip, the departure and arrival airports are replaced by the railway stations.The trip could begin in his personal automobile, on a public transit vehicle, or in a taxi .This first link of his trip takes him from home to the airport parking garage or to the door of the airport terminal. This first segment is one of several line-haul portions of the trip if he drives his car, he parks it at the airport parking garage, changing from the highway mode to the walking mode for a short distance, and then taking the shuttle bus to the airport. If he left home by public transit or taxi, he gets dropped off directly at the door to the airport terminal. The places where there is a change of mode are referred to as intermodal transfer points. Fig.1.l indicates that this trip has several points where the businessman changes mode. Although the main portion of his trip is by airplane, there are numerous other uses of the transportation system involved.Fig.1.1 A businessm an’s tripThe transportation system is organized around society’s need to provide an adequate service and involves broad interaction with many other disciplines. The transportation system itself is one of the major or functional systems of society, and is an essential feature of people’s lives, especially in wealthy societies. The goals of the transportation system are primarily economic; the most important constraints it faces are environmental. The transportation system itself may be analyzed in functiona l terms or in terms of modes of transportation. Take the businessman’s trip as an example, it is clear that each segment of his trip depends on at least one constructed facility, such as a roadway or a runway at the intermodal transfer points, constructed facilities such as parking lots or airport terminals are necessary.Transport system consists of fixed facilities, flow entities and control system that permit people and goods (freight) to overcome the friction of geographical space.(1)Fixed facilities: physical components of the system that are fixed in space and constitute the network of links;(2)Flow entities: units that traverse the fixed facilities (include vehicles, container units, railroad cars, etc.)(3)Control system: vehicular control and flow control. Vehicular control refers to the technological way in which individual vehicles are guided on the fixed facilities. Flow control system consists of the means that permit the efficient and smooth operation of streams of vehicles and the reduction of conflicts between vehicles (signing, marking, and signal systems and the concomitant rules of operation).Transportation is one of the major or functional systems of modern society. A system, in the sense intended here, is something that may be thought of as a whole consisting of parts or components. The description of a system involves identification of the system itself as distinct from its environment (that is, the rest of the world), identification of its components, and a description of how the components interact. In the case of the transportation system, the components may be conceived of in various ways. For instance, they may be thought of as entities that perform various functions (or tasks) in the provision of transportationThe transportation system is a functional system in the context of society as a whole because it provides a service the movement of goods and people from place to place that is essential to the functioning of the community as a whole. It is a major functional system because it is an essential feature in the economy and the personal lives of people everywhere, most especially in the developed nations. A highly developed transportation system makes possible the abundance and variety of goods and the high levels of personal mobility that are the hallmarks (for better or for worse) of a wealthy society. The economic scope of the transportation system is indicated by the fact that in l 998, transportation accounted for l1.2 percent of the gross domestic product and l 9 percent of the average household expenditures in the United States. Its impact on the lives of individuals is revealed by the fact that in l995 the average American made l, 568 local trips, and traveled over 27, 500 km, 5,000 km of which was for long-distance travel (trips of more than l60 km). At the same time, the transportation system is a major or source of resource consumption and environmental impact.Transportation accounts for almost two-thirds of the petroleum consumption in the United States and is a major contributor to environmental problems such as air pollution, noise, and destruction of natural habitats.If viewed in functional terms, the transportation system includes the following components:（1）Physical facilities, including streets, roads, highways, railroads, airports sea and ports, pipelines, and canals.（2）Fleets of vehicles, vessels and aircraft.（3）Operating bases and facilities, including vehicle maintenance facilities and office space.（4）Organizations. These may be classified roughly as facility-oriented organizations and operating organizations are primarily involved in planning, designing, constructing, maintaining, and operating fixed facilities. They include the United States Department of Transportation; state departments of transportation (or equivalent agencies); metropolitan planning organizations (organizations responsible for transportation planning at the level of the metropolitan region); local departments of public works, departments of transportation, and similar organizations; port authorities, and private land developers. Operating organizations, also known as carriers, are primarily concerned with operating fleets to provide transportation services. They include railroads, airlines, ship or barge lines, truck lines, transit operators, and private individuals who operate automobiles, motorcycles, and bicycles.(5)Operating strategies, including vehicle routing, scheduling, and traffic control.Fig.1.2 illustrates the ways in which the functional components of the commercial air transportation system are interrelated. Major organizations include the Federal Aviation Agency (FAA), the airlines, metropolitan planning organizations (MPOs), and airport authorities or other owners and operators of airports of airports. Of these, the FAA, the MPOs, and the airport authorities are primarily concerned with providing facilities, and hence would be considered facility-oriented organization. The FAA is responsible for design standards for air transportation facilities and provides some funding; the MPOs are involved in planning airport facilities at the local level, and the airport authorities actually own and construct the airport. The airlines are primarily concerned with operating commercial air service, and hence are operating organization. In addition, the FAA provides safety regulation (including certification of aircraft and pilots) and air traffic control. The airlines own and operate fleets of aircraft and determine operating strategies, include route structures (that is, which airport pairs are served directly and how the overall network is linked together), schedules, and various other operating policies. The major physical facilities are the airport, which consist of terminals are part of the air traffic control system and are staffed by the FAA. Most activities in the terminals are carded out by tenant organizations, including the airlines, which use them for functions such as ticketing, baggage handling, and loading and unloading aircraft. The airlines also operate the maintenance facilities, which serve as their operating bases.Fig.1.2 Interrelationship of functional components of a commercial air transportation system The provision of transportation service results when various organizations construct physical facilities and deploy fleets in accordance with their operating strategies. In order for the system to function effectively, the interactions of the various components must be understood. For instance, in order to design a highway effectively, it is necessary to know the characteristics of both the vehicles and the drivers that will use it, and to be aware of the traffic control strategies that will be employed. To give another example, to design an effective air traffic control system, it is necessary to understand the operating strategies of the airlines; the physical devices used to implement air traffic control; and the characteristics of aircraft, pilots, and airports.New Wordsconveyance n. 交通工具garage n. 车库intermodal n. 联运segment vi. 分割n. 段；部分; vt. 分割expenditure n. 支出，花费；经费，消费额metropolitan adj.大都市的；大主教辖区的；宗主国的; n.大城市人；大主教；宗主国的公民.Tenant n. 承租人；房客；佃户；居住者; vt. 租借（常用于被动语态）; n. (Tenant) 人名；(法) 特南Implement vt. 实施，执行；实现，使生效; n. 工具，器具；手段Mobility n. 移动性；机动性；[电子] 迁移率Mph miles per hour （速度单位：英里/每小时）Note to the Text（1）Transportation engineering（交通工程）：the application of scientific principles to the planning, design, operation, and management of transportation system.（2）Transportation is typically system engineering, A system is a set of interrelated parts, called components that perform a number of functions in order to achieve common goals.运输系统是由一组具有相关执行功能的组件组合在一起，以实现共同目标。

As I sit here, reflecting on the past few years, I cant help but marvel at the profound changes that have taken place in my life. The journey from a naive high school student to a more mature and selfaware individual has been filled with challenges, discoveries, and growth. This essay is a tribute to the transformation Ive experienced, both in my academic pursuits and personal life.High school was a time of routine and predictability. Each day was a repetition of the last, with classes, homework, and extracurricular activities forming the backbone of my existence. I was part of a welloiled machine, where every cog knew its place and function. However, as I stepped into the university, everything changed. The structure that once provided comfort now seemed restrictive, and I was thrust into a world of freedom and selfdetermination.The first major change was academic. In high school, my learning was largely passive I absorbed information from textbooks and lectures, regurgitated it during exams, and moved on. But university demanded more. It required critical thinking, independent research, and the ability to synthesize diverse ideas into a coherent understanding. The first time I had to write a research paper, I was overwhelmed. The sheer volume of information, the need to analyze and evaluate sources, and the pressure to present a wellargued thesis were daunting. Yet, as I delved deeper into the subject, I found a sense of excitement and satisfaction in constructing my own arguments and perspectives. It was empowering to realize that I could contribute to the academic discourse, that my voice mattered.Another significant change was in my social life. High school friendships were often based on proximity and shared classes, but university introduced me to a diverse community of individuals with unique backgrounds and interests. I found myself in conversations that spanned cultures, philosophies, and experiences, broadening my worldview and challenging my preconceived notions. I learned the value of empathy and openmindedness, and the importance of respecting differing opinions.Living away from home also forced me to become more independent. In high school, my parents took care of most aspects of my life, from meals to laundry. But in university, I was responsible for my own wellbeing. I had to manage my time effectively, budget my finances, and take care of my health. There were moments of struggle, like when I had to cook a meal for the first time or when I fell ill and had to take care of myself. Yet, these experiences taught me resilience and selfreliance.Moreover, the transition to university life also brought about a change in my approach to extracurricular activities. In high school, I was involved in various clubs and sports teams, but my participation was often driven by external expectations. University, however, allowed me to pursue my passions without the pressure of competition or recognition. I joined a volunteer organization that focused on environmental conservation, not for accolades, but because I genuinely cared about the cause. This shift in motivation brought a deeper sense of fulfillment and purpose.The changes in my life have not been without their challenges. There were times of loneliness, stress, and selfdoubt. But these experiences have alsobeen instrumental in my personal growth. They have taught me to be adaptable, to seek help when needed, and to believe in my own abilities.In conclusion, the transition from high school to university has been a transformative journey. It has broadened my intellectual horizons, enriched my social experiences, and fostered personal independence. It has been a period of exploration, selfdiscovery, and growth. While I miss the simplicity of high school life, I embrace the complexities and opportunities that university life offers. It is a chapter of my life that I will always cherish and draw strength from.。