Adaptive Caching by Refetching (View in Color)
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Boosting原理及应用[object Object]Boosting是一种用于提升机器学习模型性能的集成学习方法,它通过训练一系列弱分类器,并将它们组合成一个强分类器。
Boosting的原理是通过迭代的方式,逐步改进弱分类器的性能,使得它们在错误分类的样本上有更高的权重,从而达到提升整体分类性能的目的。
Boosting的核心思想是将多个弱分类器进行加权组合,使得它们能够协同工作,并形成一个更强大的分类器。
在每一轮迭代中,Boosting会根据上一轮分类器的性能调整样本权重,使得对错误分类的样本施加更高的权重,从而在下一轮中更加关注这些难以分类的样本。
这种迭代的过程会一直进行,直到达到一定的迭代次数或者分类器的性能不再提升为止。
1. Adaboost(Adaptive Boosting):Adaboost是Boosting算法最经典的实现之一,它通过迭代的方式训练一系列弱分类器,并将它们加权组合成一个强分类器。
Adaboost的特点是能够适应不同的数据分布,对于难以分类的样本会给予更高的权重,从而提升整体的分类性能。
2. Gradient Boosting:Gradient Boosting是一种通过梯度下降的方式逐步优化模型性能的Boosting算法。
它的核心思想是在每一轮迭代中,计算损失函数的负梯度,并将其作为下一轮训练样本的权重调整。
通过迭代的方式,逐步改进弱分类器的性能,从而提升整体的分类准确率。
3. XGBoost(eXtreme Gradient Boosting):XGBoost是Gradient Boosting的一种优化实现,它在Gradient Boosting的基础上引入了一些创新的技术,如正则化、缺失值处理和并行计算等。
XGBoost在很多机器学习竞赛中取得了优秀的成绩,并被广泛应用于各种实际问题中。
4. LightGBM:LightGBM是一种基于梯度提升树的Boosting算法,它在XGBoost的基础上进行了一些改进,使得它能够更快地训练模型,并具有更低的内存消耗。
Legal informationCopyright and License© Copyright 2019 HP Development Company, L.P.Reproduction, adaptation, or translation without prior written permission is prohibited, except as allowedunder the copyright laws.The information contained herein is subject to change without notice.The only warranties for HP products and services are set forth in the express warranty statementsaccompanying such products and services. Nothing herein should be construed as constituting anadditional warranty. HP shall not be liable for technical or editorial errors or omissions contained herein.Edition 1, 10/2019Trademark CreditsAdobe®, Adobe Photoshop®, Acrobat®, and PostScript® are trademarks of Adobe Systems Incorporated.Apple and the Apple logo are trademarks of Apple Inc., registered in the U.S. and other countries.macOS is a trademark of Apple Inc., registered in the U.S. and other countries.AirPrint is a trademark of Apple Inc., registered in the U.S. and other countries.Google™ is a trademark of Google Inc.Microsoft®, Windows®, Windows® XP, and Windows Vista® are U.S. registered trademarks of MicrosoftCorporation.UNIX® is a registered trademark of The Open Group.iiiT able of contents1 Printer overview (1)Warning icons (1)Potential shock hazard (2)Printer views (2)Printer front view (2)Printer back view (4)Interface ports (4)Control-panel view (5)How to use the touchscreen control panel (7)Printer specifications (8)T echnical specifications (8)Supported operating systems (11)Mobile printing solutions (12)Printer dimensions (13)Power consumption, electrical specifications, and acoustic emissions (15)Operating-environment range (15)Printer hardware setup and software installation (16)2 Paper trays (17)Introduction (17)Load paper to Tray 1 (multipurpose tray) (17)Load Tray 1 (multipurpose tray) (18)Tray 1 paper orientation (19)Use alternative letterhead mode (24)Enable Alternative Letterhead Mode by using the printer control-panel menus (24)Load paper to Tray 2 (24)Load Tray 2 (24)Tray 2 paper orientation (26)Use alternative letterhead mode (29)Enable Alternative Letterhead Mode by using the printer control-panel menus (29)Load paper to the 550-sheet paper tray (30)Load paper to the 550-sheet paper tray (30)550-sheet paper tray paper orientation (32)Use alternative letterhead mode (35)Enable Alternative Letterhead Mode by using the printer control-panel menus (35)ivLoad paper to the 2 x 550-sheet paper trays (36)Load paper to the 2 x 550-sheet paper trays (36)2 x 550-sheet paper tray paper orientation (38)Use alternative letterhead mode (41)Enable Alternative Letterhead Mode by using the printer control-panel menus (41)Load paper to the 2,700-sheet high-capacity input paper trays (41)Load paper to the 2,700-sheet high-capacity input paper trays (41)2,700-sheet HCI paper tray paper orientation (43)Use alternative letterhead mode (45)Enable Alternative Letterhead Mode by using the printer control-panel menus (45)Load and print envelopes (46)Print envelopes (46)Envelope orientation (46)Load and print labels (47)Manually feed labels (47)Label orientation (48)3 Supplies, accessories, and parts (49)Order supplies, accessories, and parts (49)Ordering (49)Supplies and accessories (50)Maintenance/long-life consumables (51)Customer self-repair parts (51)Dynamic security (52)Configure the HP toner-cartridge-protection supply settings (53)Introduction (53)Enable or disable the Cartridge Policy feature (53)Use the printer control panel to enable the Cartridge Policy feature (54)Use the printer control panel to disable the Cartridge Policy feature (54)Use the HP Embedded Web Server (EWS) to enable the Cartridge Policy feature (54)Use the HP Embedded Web Server (EWS) to disable the Cartridge Policy feature (55)Troubleshoot Cartridge Policy control panel error messages (55)Enable or disable the Cartridge Protection feature (55)Use the printer control panel to enable the Cartridge Protection feature (56)Use the printer control panel to disable the Cartridge Protection feature (56)Use the HP Embedded Web Server (EWS) to enable the Cartridge Protection feature (56)Use the HP Embedded Web Server (EWS) to disable the Cartridge Protection feature (57)Troubleshoot Cartridge Protection control panel error messages (57)Replace the toner cartridges (58)T oner-cartridge information (58)Remove and replace the cartridges (59)Replace the imaging drums (62)Imaging drum information (62)Remove and replace the imaging drums (63)Replace the toner-collection unit (66)T oner-collection unit information (66)vRemove and replace the toner-collection unit (67)Replace the staple cartridge (M776zs model only) (70)Staple cartridge information (70)Remove and replace the staple cartridge (71)4 Print (73)Print tasks (Windows) (73)How to print (Windows) (73)Automatically print on both sides (Windows) (74)Manually print on both sides (Windows) (74)Print multiple pages per sheet (Windows) (75)Select the paper type (Windows) (75)Additional print tasks (76)Print tasks (macOS) (77)How to print (macOS) (77)Automatically print on both sides (macOS) (77)Manually print on both sides (macOS) (77)Print multiple pages per sheet (macOS) (78)Select the paper type (macOS) (78)Additional print tasks (79)Store print jobs on the printer to print later or print privately (79)Introduction (79)Create a stored job (Windows) (79)Create a stored job (macOS) (80)Print a stored job (81)Delete a stored job (81)Delete a job that is stored on the printer (81)Change the job storage limit (82)Information sent to printer for Job Accounting purposes (82)Mobile printing (82)Introduction (82)Wi-Fi, Wi-Fi Direct Print, NFC, and BLE printing (82)Enable wireless printing (83)Change the Wi-Fi Direct name (83)HP ePrint via email (83)AirPrint (84)Android embedded printing (85)Print from a USB flash drive (85)Enable the USB port for printing (85)Method one: Enable the USB port from the printer control panel (85)Method two: Enable the USB port from the HP Embedded Web Server (network-connectedprinters only) (85)Print USB documents (86)Print using high-speed USB 2.0 port (wired) (86)Method one: Enable the high-speed USB 2.0 port from the printer control panel menus (86)Method two: Enable the high-speed USB 2.0 port from the HP Embedded Web Server (network-connected printers only) (87)vi5 Copy (88)Make a copy (88)Copy on both sides (duplex) (90)Additional copy tasks (92)6 Scan (93)Set up Scan to Email (93)Introduction (93)Before you begin (93)Step one: Access the HP Embedded Web Server (EWS) (94)Step two: Configure the Network Identification settings (95)Step three: Configure the Send to Email feature (96)Method one: Basic configuration using the Email Setup Wizard (96)Method two: Advanced configuration using the Email Setup (100)Step four: Configure the Quick Sets (optional) (104)Step five: Set up Send to Email to use Office 365 Outlook (optional) (105)Introduction (105)Configure the outgoing email server (SMTP) to send an email from an Office 365 Outlookaccount (105)Set up Scan to Network Folder (108)Introduction (108)Before you begin (108)Step one: Access the HP Embedded Web Server (EWS) (108)Step two: Set up Scan to Network Folder (109)Method one: Use the Scan to Network Folder Wizard (109)Method two: Use Scan to Network Folder Setup (110)Step one: Begin the configuration (110)Step two: Configure the Scan to Network Folder settings (111)Step three: Complete the configuration (118)Set up Scan to SharePoint (118)Introduction (118)Before you begin (118)Step one: Access the HP Embedded Web Server (EWS) (118)Step two: Enable Scan to SharePoint and create a Scan to SharePoint Quick Set (119)Scan a file directly to a SharePoint site (121)Quick Set scan settings and options for Scan to SharePoint (122)Set up Scan to USB Drive (123)Introduction (124)Step one: Access the HP Embedded Web Server (EWS) (124)Step two: Enable Scan to USB Drive (124)Step three: Configure the Quick Sets (optional) (125)Default scan settings for Scan to USB Drive setup (126)Default file settings for Save to USB setup (126)Scan to email (127)Introduction (127)Scan to email (127)Scan to job storage (129)viiIntroduction (129)Scan to job storage on the printer (130)Print from job storage on the printer (132)Scan to network folder (132)Introduction (132)Scan to network folder (132)Scan to SharePoint (134)Introduction (134)Scan to SharePoint (134)Scan to USB drive (136)Introduction (136)Scan to USB drive (136)Use HP JetAdvantage business solutions (138)Additional scan tasks (138)7 Fax (140)Set up fax (140)Introduction (140)Set up fax by using the printer control panel (140)Change fax configurations (141)Fax dialing settings (141)General fax send settings (142)Fax receive settings (143)Send a fax (144)Additional fax tasks (146)8 Manage the printer (147)Advanced configuration with the HP Embedded Web Server (EWS) (147)Introduction (147)How to access the HP Embedded Web Server (EWS) (148)HP Embedded Web Server features (149)Information tab (149)General tab (149)Copy/Print tab (150)Scan/Digital Send tab (151)Fax tab (152)Supplies tab (153)Troubleshooting tab (153)Security tab (153)HP Web Services tab (154)Networking tab (154)Other Links list (156)Configure IP network settings (157)Printer sharing disclaimer (157)View or change network settings (157)Rename the printer on a network (157)viiiManually configure IPv4 TCP/IP parameters from the control panel (158)Manually configure IPv6 TCP/IP parameters from the control panel (158)Link speed and duplex settings (159)Printer security features (160)Introduction (160)Security statements (160)Assign an administrator password (160)Use the HP Embedded Web Server (EWS) to set the password (160)Provide user access credentials at the printer control panel (161)IP Security (161)Encryption support: HP High Performance Secure Hard Disks (161)Lock the formatter (161)Energy-conservation settings (161)Set the sleep timer and configure the printer to use 1 watt or less of power (161)Set the sleep schedule (162)Set the idle settings (162)HP Web Jetadmin (163)Software and firmware updates (163)9 Solve problems (164)Customer support (164)Control panel help system (165)Reset factory settings (165)Introduction (165)Method one: Reset factory settings from the printer control panel (165)Method two: Reset factory settings from the HP Embedded Web Server (network-connectedprinters only) (166)A “Cartridge is low” or “Cartridge is very low” message displays on the printer control panel (166)Change the “Very Low” settings (166)Change the “Very Low” settings at the control panel (166)For printers with fax capability (167)Order supplies (167)Printer does not pick up paper or misfeeds (167)Introduction (167)The printer does not pick up paper (167)The printer picks up multiple sheets of paper (171)The document feeder jams, skews, or picks up multiple sheets of paper (174)Clear paper jams (174)Introduction (174)Paper jam locations (174)Auto-navigation for clearing paper jams (175)Experiencing frequent or recurring paper jams? (175)Clear paper jams in the document feeder - 31.13.yz (176)Clear paper jams in Tray 1 (13.A1) (177)Clear paper jams in Tray 2 (13.A2) (182)Clear paper jams in the fuser (13.B9, 13.B2, 13.FF) (188)ixClear paper jams in the duplex area (13.D3) (194)Clear paper jams in the 550-sheet trays (13.A3, 13.A4) (199)Clear paper jams in the 2 x 550 paper trays (13.A4, 13.A5) (206)Clear paper jams in the 2,700-sheet high-capacity input paper trays (13.A3, 13.A4, 13.A5, 13.A7) (213)Resolving color print quality problems (220)Introduction (220)Troubleshoot print quality (221)Update the printer firmware (221)Print from a different software program (221)Check the paper-type setting for the print job (221)Check the paper type setting on the printer (221)Check the paper type setting (Windows) (221)Check the paper type setting (macOS) (222)Check toner-cartridge status (222)Step one: Print the Supplies Status Page (222)Step two: Check supplies status (222)Print a cleaning page (222)Visually inspect the toner cartridge or cartridges (223)Check paper and the printing environment (223)Step one: Use paper that meets HP specifications (223)Step two: Check the environment (223)Step three: Set the individual tray alignment (224)Try a different print driver (224)Troubleshoot color quality (225)Calibrate the printer to align the colors (225)Troubleshoot image defects (225)Improve copy image quality (233)Check the scanner glass for dirt and smudges (233)Calibrate the scanner (234)Check the paper settings (235)Check the paper selection options (235)Check the image-adjustment settings (235)Optimize copy quality for text or pictures (236)Edge-to-edge copying (236)Improve scan image quality (236)Check the scanner glass for dirt and smudges (237)Check the resolution settings (238)Check the color settings (238)Check the image-adjustment settings (239)Optimize scan quality for text or pictures (239)Check the output-quality settings (240)Improve fax image quality (240)Check the scanner glass for dirt and smudges (240)Check the send-fax resolution settings (242)Check the image-adjustment settings (242)Optimize fax quality for text or pictures (242)Check the error-correction setting (243)xSend to a different fax machine (243)Check the sender's fax machine (243)Solve wired network problems (244)Introduction (244)Poor physical connection (244)The computer is unable to communicate with the printer (244)The printer is using incorrect link and duplex settings for the network (245)New software programs might be causing compatibility problems (245)The computer or workstation might be set up incorrectly (245)The printer is disabled, or other network settings are incorrect (245)Solve wireless network problems (245)Introduction (245)Wireless connectivity checklist (245)The printer does not print after the wireless configuration completes (246)The printer does not print, and the computer has a third-party firewall installed (246)The wireless connection does not work after moving the wireless router or printer (247)Cannot connect more computers to the wireless printer (247)The wireless printer loses communication when connected to a VPN (247)The network does not appear in the wireless networks list (247)The wireless network is not functioning (247)Reduce interference on a wireless network (248)Solve fax problems (248)Checklist for solving fax problems (248)What type of phone line are you using? (249)Are you using a surge-protection device? (249)Are you using a phone company voice-messaging service or an answering machine? (249)Does your phone line have a call-waiting feature? (249)Check fax accessory status (249)General fax problems (250)The fax failed to send (250)No fax address book button displays (250)Not able to locate the Fax settings in HP Web Jetadmin (250)The header is appended to the top of the page when the overlay option is enabled (251)A mix of names and numbers is in the recipients box (251)A one-page fax prints as two pages (251)A document stops in the document feeder in the middle of faxing (251)The volume for sounds coming from the fax accessory is too high or too low (251)Index (252)xiPrinter overview1Review the location of features on the printer, the physical and technical specifications of the printer,and where to locate setup information.For video assistance, see /videos/LaserJet.The following information is correct at the time of publication. For current information, see /support/colorljM776MFP.For more information:HP's all-inclusive help for the printer includes the following information:●Install and configure●Learn and use●Solve problems●Download software and firmware updates●Join support forums●Find warranty and regulatory informationWarning iconsUse caution if you see a warning icon on your HP printer, as indicated in the icon definitions.●Caution: Electric shock●Caution: Hot surface●Caution: Keep body parts away from moving partsPrinter overview1●Caution: Sharp edge in close proximity●WarningPotential shock hazardReview this important safety information.●Read and understand these safety statements to avoid an electrical shock hazard.●Always follow basic safety precautions when using this product to reduce risk of injury from fire orelectric shock.●Read and understand all instructions in the user guide.●Observe all warnings and instructions marked on the product.●Use only a grounded electrical outlet when connecting the product to a power source. If you do notknow whether the outlet is grounded, check with a qualified electrician.●Do not touch the contacts on any of the sockets on the product. Replace damaged cordsimmediately.●Unplug this product from wall outlets before cleaning.●Do not install or use this product near water or when you are wet.●Install the product securely on a stable surface.●Install the product in a protected location where no one can step on or trip over the power cord.Printer viewsIdentify certain parts of the printer and the control panel.Printer front viewLocate features on the front of the printer.2Chapter 1 Printer overviewPrinter front view3Printer back viewLocate features on the back of the printer.Interface portsLocate the interface ports on the printer formatter. 4Chapter 1 Printer overviewControl-panel viewThe control panel provides access to the printer features and indicates the current status of the printer.NOTE:Tilt the control panel for easier viewing.The Home screen provides access to the printer features and indicates the current status of the printer.screens.NOTE:The features that appear on the Home screen can vary, depending on the printerconfiguration.Control-panel view5Figure 1-1Control-panel view?i 12:42 PM6Chapter 1 Printer overviewHow to use the touchscreen control panelPerform the following actions to use the printer touchscreen control panel.T ouchT ouch an item on the screen to select that item or open that menu. Also, when scrolling T ouch the Settings icon to open the Settings app.How to use the touchscreen control panel 7SwipeT ouch the screen and then move your finger horizontally to scroll the screen sideways.Swipe until the Settings app displays.Printer specificationsDetermine the specifications for your printer model.IMPORTANT:The following specifications are correct at the time of publication, but they are subject to change. For current information, see /support/colorljM776MFP .T echnical specificationsReview the printer technical specifications.Product numbers for each model ●M776dn - #T3U55A ●Flow M776z - #3WT91A ●Flow M776zs - #T3U56APaper handling specificationsPaper handling features Tray 1 (100-sheet capacity)Included Included Included Tray 2 (550-sheet capacity)IncludedIncludedIncluded8Chapter 1 Printer overview550-sheet paper trayOptional Included Not included NOTE:The M776dn models accept one optional550-sheet tray.Optional Included Included2 x 550-sheet paper tray and standNOTE:The M776dn models accept one optional550-sheet tray that may be installed on top of thestand.Optional Not included Not included2,700-sheet high-capacity input (HCI) paper trayand standNOTE:The M776dn models accept one optional550-sheet tray that may be installed on top of theoptional printer stand.Printer standOptional Not included Not included NOTE:The M776dn models accept one optional550-sheet tray that may be installed on top of theoptional printer stand.Inner finisher accessory Not included Not included Included Automatic duplex printing Included IncludedIncludedIncluded Included Included10/100/1000 Ethernet LAN connection with IPv4and IPv6Hi-Speed USB 2.0Included Included IncludedIncluded Included IncludedEasy-access USB port for printing from a USBflash drive or upgrading the firmwareIncluded Included Included Hardware Integration Pocket for connectingaccessory and third-party devicesHP Internal USB Ports Optional Optional OptionalOptional Optional OptionalHP Jetdirect 2900nw Print Server accessory forWi-Fi connectivity and an additional Ethernet portOptional IncludedIncludedHP Jetdirect 3100w accessory for Wi-Fi, BLE, NFC,and proximity badge readingPrints 45 pages per minute (ppm) on Letter-sizepaper and 46 ppm on A4-size paperEasy-access USB printing for printing from a USBIncluded Included Includedflash driveT echnical specifications9Included Included Included Store jobs in the printer memory to print later orprint privatelyScans 100 pages per minute (ppm) on A4 andIncluded Included Included letter-size paper one-sidedIncluded Included Included 200-page document feeder with dual-headscanning for single-pass duplex copying andscanningNot included Included Included HP EveryPage T echnologies including ultrasonicmulti-feed detectionNot included Included Included Embedded optical character recognition (OCR)provides the ability to convert printed pages intotext that can be edited or searched using acomputerIncluded Included Included SMART Label feature provides paper-edgedetection for automatic page croppingIncluded Included Included Automatic page orientation for pages that haveat least 100 characters of textIncluded Automatic tone adjustment sets contrast,Included Includedbrightness, and background removal for eachpageIncluded Included Includedfolders on a networkIncludedSend documents to SharePoint®Included IncludedIncluded Included Included NOTE:Memory reported on the configurationpage will change from 2.5 GB to 3 GB with theoptional 1 GB SODIMM installed.Mass storage: 500 GB hard disk drive Included Included IncludedSecurity: HP Trusted Platform Module (TPM)Included Included IncludedT ouchscreen control panel Included Included IncludedRetractable keyboard Not included Included Included 10Chapter 1 Printer overviewFax Optional Included IncludedSupported operating systemsUse the following information to ensure printer compatibility with your computer operating system.Linux: For information and print drivers for Linux, go to /go/linuxprinting.UNIX: For information and print drivers for UNIX®, go to /go/unixmodelscripts.The following information applies to the printer-specific Windows HP PCL 6 print drivers, HP print driversfor macOS, and to the software installer.Windows: Download HP Easy Start from /LaserJet to install the HP print driver. Or, go tothe printer-support website for this printer: /support/colorljM776MFP to download the printdriver or the software installer to install the HP print driver.macOS: Mac computers are supported with this printer. Download HP Easy Start either from /LaserJet or from the Printer Support page, and then use HP Easy Start to install the HP print driver.1.Go to /LaserJet.2.Follow the steps provided to download the printer software.Windows 7, 32-bit and 64-bit The “HP PCL 6” printer-specific print driver is installed for this operating system aspart of the software installation.Windows 8.1, 32-bit and 64-bit The “HP PCL-6” V4 printer-specific print driver is installed for this operating systemas part of the software installation.Windows 10, 32-bit and 64-bit The “HP PCL-6” V4 printer-specific print driver is installed for this operating systemas part of the software installation.Windows Server 2008 R2, SP 1, 64-bit The PCL 6 printer-specific print driver is available for download from the printer-support website. Download the driver, and then use the Microsoft Add Printer tool toinstall it.Windows Server 2012, 64-bit The PCL 6 printer-specific print driver is available for download from the printer-support website. Download the driver, and then use the Microsoft Add Printer tool toinstall it.Windows Server 2012 R2, 64-bit The PCL 6 printer-specific print driver is available for download from the printer-support website. Download the driver, and then use the Microsoft Add Printer tool toinstall it.Windows Server 2016, 64-bit The PCL 6 printer-specific print driver is available for download from the printer-support website. Download the driver, and then use the Microsoft Add Printer tool toinstall it.Windows Server 2019, 64-bit The PCL 6 printer-specific print driver is available for download from the printer-support website. Download the driver, and then use the Microsoft Add Printer tool toinstall it.Supported operating systems11macOS 10.13 High Sierra, macOS 10.14 MojaveDownload HP Easy Start from /LaserJet , and then use it to install the print driver.NOTE:Supported operating systems can change.NOTE:For a current list of supported operating systems and HP’s all-inclusive help for the printer, go to /support/colorljM776MFP .NOTE:For details on client and server operating systems and for HP UPD driver support for this printer, go to /go/upd . Under Additional information , click Specifications .●Internet connection●Dedicated USB 1.1 or 2.0 connection or a network connection● 2 GB of available hard-disk space ●1 GB RAM (32-bit) or2 GB RAM (64-bit)●Internet connection●Dedicated USB 1.1 or 2.0 connection or a network connection●1.5 GB of available hard-disk spaceNOTE:The Windows software installer installs the HP Smart Device Agent Base service. The file size is less than 100 kb. Its only function is to check for printers connected via USB hourly. No data is collected. If a USB printer is found, it then tries to locate a JetAdvantage Management Connector (JAMc) instance on the network. If a JAMc is found, the HP Smart Device Agent Base is securelyupgraded to a full Smart Device Agent from JAMc, which will then allow printed pages to be accounted for in a Managed Print Services (MPS) account. The driver-only web packs downloaded from for the printer and installed through the Add Printer wizard do not install this service.T o uninstall the service, open the Control Panel , select Programs or Programs and Features , and then select Add/Remove Programs or Uninstall a Programto remove the service. The file name isHPSmartDeviceAgentBase.Mobile printing solutionsHP offers multiple mobile printing solutions to enable easy printing to an HP printer from a laptop, tablet, smartphone, or other mobile device.T o see the full list and to determine the best choice, go to /go/MobilePrinting .NOTE:Update the printer firmware to ensure all mobile printing capabilities are supported.●Wi-Fi Direct (wireless models only, with HP Jetdirect 3100w BLE/NFC/Wireless accessory installed)●HP ePrint via email (Requires HP Web Services to be enabled and the printer to be registered with HP Connected)●HP Smart app ●Google Cloud Print12Chapter 1 Printer overview。
Boost your existing WiFi OverviewThe NETGEAR WiFi Range Extender boosts your existing WiFi and delivers greater wireless speed where the signal is intermittent or weak, improve range & connectivity you desire for iPads ®, smartphones, laptops & more.. The convenient wall-plug design enables placement wherever there’s a power outlet.• Works with any WiFi router• Extend WiFi for mobile devices • Reduce mobile data plan charges• Convenient wall-plug designN150 WiFi Range Extender Data SheetWN1000RPBoost WiFiBoost existing WiFi coverage throughout your home.Ideal for Mobile DevicesImprove WiFi strength for smartphones,tablets, laptops & more.CompatibleWorks with any existing WiFi router or gateway.It’s EasyEasy installation using any web browser;no CD required.Eliminate Dead ZonesEliminate WiFi dead zones and enjoy a more reliable WiFi connection.Reduce BillsReduce 3G/4G mobile data plan charges by connecting to WiFi.Ideal for Tablets &SmartphonesExisting WiFiSometimes your router does not provide the WiFi coverage you needExtenderBoosts the range of your existing WiFi & creates a stronger signal in hard-to-reach areasNetwork ConnectionsRouter connection status Mobile device connection status Secure connection (WPS)Connect to powerPower on/offN150RangeExtender Data Sheet WiFiWN1000RP WiFi Analytics AppHow strong is your WiFi signal? Use the NETGEAR WiFi Analytics app & get advanced analytics to optimize your existing or newly extended WiFi network. Check your network status, WiFi signal strength, identify crowded WiFi channels & much more!Here’s what you can do with the WiFi Analytics App!• Get a network status overview• Check WiFi signal strength• Measure WiFi channel interference• Keep track of WiFi strength by location• And more...Scan to install appThis product is packaged with a limited warranty, the acceptance of which is a condition of sale. Warranty valid only when purchased from a NETGEAR authorized reseller.* 24/7 basic technical support provided for 90 days from date of purchase when purchased from a NETGEAR authorized reseller.1Works with devices supporting Wi-Fi Protected Setup™ (WPS).Data throughput, signal range, and wireless coverage per sq. ft. are not guaranteed and may vary due to differences in operating environments of wireless networks, including without limitation building materials and wireless interference. Specifications are subject to change without notice.NETGEAR, and the NETGEAR Logo are trademarks of NETGEAR, Inc. Mac and the Mac logo are trademarks of Apple Inc. Any other trademarks herein are for reference purposes only. ©2015 NETGEAR, Inc.NETGEAR, Inc. 350 E. Plumeria Drive, San Jose, CA 95134-1911 USA, /supportD-WN1000RP-3N150 WiFi Range Extender Data SheetWN1000RPPackage Contents• N150 WiFi Range Extender (WN1000RP)• Installation guidePhysical Specifications• Dimensions: 2.64 x 2.17 x 1.34 in (67.05 x 55.11 x 34.03 mm)• Weight: 0.22 lb (.099 kg)Warranty• Warranty localized to country of saleSecurity• WiFi Protected Access® (WPA/WPA2-PSK)and WEPStandards• IEEE® 802.11 b/g 2.4GHz with some 11nfeaturesSupport• 24/7 basic technical support free for 90 daysEase of Use• CD-less setup—great for mobile devices • Push ‘N’ Connect using Wi-Fi Protected Setup® (WPS)1System Requirements• 2.4GHz 802.11 b/g/n wireless router or gateway • Microsoft® Internet Explorer® 5.0, Firefox® 2.0 or Safari® 1.4 or Google Chrome 11.0 browsersor higher。
负载均衡load balance的英文缩写Title: Load Balance (LB): The Cornerstone of Efficient Resource ManagementIntroductionIn the realm ofputing and networking, one term that frequently crops up is "Load Balance" or LB for short. This concept plays a pivotal role in optimizing resource utilization, enhancing system performance, and ensuring fault tolerance. In this article, we will delve into the intricacies of load balancing, its significance, and how it contributes to efficient resource management.What is Load Balancing?Load balancing refers to the methodical distribution of network traffic across multiple servers to optimize resource utilization, enhance responsiveness, and avoid overloading any single server. It is an essentialponent of fault-tolerant systems as it ensures that no single point of failure exists.The Importance of Load BalancingThe importance of load balancing can be summed up in three main points:1. Improved Performance: By distributing the workload evenly across multiple servers, each server operates within its optimal capacity, leading to better overall system performance.2. Enhanced Availability: If one server fails or needs maintenance, the load balancer redirects traffic to other available servers, thereby ensuring continuous service availability.3. Scalability: As the demand for services increases, new servers can be added to the system without disrupting existing services. This allows for easy expansion and scalability of the system.How does Load Balancing Work?Load balancing typically involves the use of a software or hardware device called a load balancer. The load balancer acts as a traffic cop, directing client requests to the various backend servers based on certain predefined algorithms and policies. These algorithms may consider factors such as server availability, server load, geographic location, or specific application requirements.Types of Load Balancing AlgorithmsThere are several types of load balancing algorithms, including:1. Round Robin: Each iing request is assigned to the next available server in a rotation.2. Least Connections: New requests are sent to the server with the fewest active connections.3. IP Hash: A hash function is used to determine which server should handle a request based on the client's IP address.4. Weighted Algorithms: Servers are assigned weights based on their processing power or capacity, and requests are distributed accordingly.ConclusionLoad balancing (LB) is a crucial aspect of modernputing and networking infrastructure. Its ability to distribute workloads efficiently, ensure high availability, and facilitate scalability makes it an indispensable tool for managing resources effectively. Understanding the concepts and mechanisms behind load balancing can help organizations make informed decisions about their IT infrastructure and improve the overall user experience.。
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)。
abstractvalueadaptingcache 的get 和lookup -回复题目: abstractvalueadaptingcache 的get 和lookup 方法详解摘要: abstractvalueadaptingcache是在缓存系统中常用的一种机制,它通过get和lookup方法来实现缓存数据的获取和查找。
本文将详细介绍abstractvalueadaptingcache的概念、用途以及如何使用get和lookup 方法。
第一部分: 概念介绍abstractvalueadaptingcache是一种在缓存系统中经常使用的机制。
它允许将缓存与外部数据源进行适配,以便在缓存系统中实现更高效的数据访问。
abstractvalueadaptingcache的主要功能是在缓存数据的获取和查找时进行适配转换。
第二部分: 使用get方法获取缓存数据在abstractvalueadaptingcache中,get方法是用来获取缓存数据的主要方式。
当我们需要从缓存中获取数据时,可以使用get方法来实现。
get方法的使用步骤如下:1. 调用get方法并传入需要获取数据的Key。
例如: cache.get(key)。
2. 系统会首先在缓存中查找对应的数据。
3. 如果找到了匹配的数据,则直接返回该数据。
4. 如果没有找到匹配的数据,则尝试从外部数据源中获取数据。
5. 如果从外部数据源中获取到了数据,则将数据放入缓存中,并返回。
get方法的一些注意事项:1. get方法返回的数据类型通常是Object,需要根据实际情况进行类型转换。
2. 在使用get方法时,需要注意缓存的过期时间和淘汰策略,以保证数据的准确性和及时性。
3. 在高并发情况下,可能会出现多个线程同时进行数据获取的情况,需要注意并发安全性。
第三部分: 使用lookup方法查找缓存数据除了get方法,abstractvalueadaptingcache还提供了lookup方法来实现缓存数据的查找。
Philips Brilliance32:10 SuperWide curved LCD displayP Line43 (43.4" / 110.2 cm diag.)3840 x 1200439P9HWide open possibilitieswith two high-performance monitors in onePhilips 43” curved 32:10 SuperWide display is like two full-size high-performancemonitors in-one. Productivity enhancing features like USB-C and pop-up webcam with Windows Hello deliver performance and convenience you expect.Expand your horizons•32:10 SuperWide designed to replace multiscreen setups •MultiView enables simultaneous dual connection and view •1800r curved display for a more immersive experience •Effortlessly smooth action with Adaptive-Sync technology Optimal Connectivity•Built in USB-C docking station•Built-in KVM switch to easily switch between sources Designed for the way you work•Securely sign in with pop-up webcam with Windows Hello™•DisplayHDR 400 for more lifelike and outstanding visuals •Less eye fatigue with Flicker-free technology •LowBlue Mode for easy on-the-eyes productivity•Tilt, swivel and height-adjust for an ideal viewing positionHighlights32:10 SuperWide32:10 SuperWide 43" screen, with 3840 x 1200 resolution, is designed to replace multiscreen setups for massive wide view. It's like having two 16:10 displays side-by-side. SuperWide monitors offer screen area of dual monitors without the complicated setup.Adaptive-Sync technologyGaming shouldn't be a choice between choppy gameplay or broken frames. Get fluid, artifact-free performance at virtually any framerate with Adaptive-Sync technology, smooth quick refresh and ultra-fast response time.MultiView technologyWith the ultra-high resolution PhilipsMultiView display you can now experience a world of connectivity. MultiView enables active dual connect and view so that you can workwith multiple devices like a PC and notebook simultaneously, for complex multi-tasking.1800r Curved displayInnovative curved display offers less image distortion, a wider field of view, reduced glare, and more comfort for eyes.Built in USB-C docking stationThis Philips display features a built-in USB type-C docking station with power delivery. Its slim, reversible USB-C connector allows for easy, one-cable docking. Simplify by connecting all your peripherals like keyboard, mouse and your RJ-45 Ethernet cable to the monitor's docking station. Simply connect yournotebook and this monitor with a single USB-C cable to watch high-resolution video and transfer super-speed data, while powering up and re-charging your notebook at the same time.MultiClient Integrated KVMWith MultiClient Integrated KVM switch, you can control two separate PCs with onemonitor-keyboard-mouse set up. A convenient button allows you to quickly switch between sources. Handy with set-ups that require dualPC computing power or sharing one large monitor to show two different PCs.Windows Hello™ pop-up webcamPhilips' innovative and secure webcam pops up when you need it and securely tucks back into the monitor when you are not using it. The webcam is also equipped with advanced sensors for Windows Hello™ facialrecognition, which conveniently logs you into your Windows devices in less than 2 seconds, 3 times faster than a password.DisplayHDR 400VESA-certified DisplayHDR 400 delivers a significant step-up from normal SDR displays. Unlike, other 'HDR compatible' screens, true DisplayHDR 400 produces astonishingbrightness, contrast and colors. With global dimming and peak brightness up-to 400 nits, images come to life with notable highlights while featuring deeper, more nuanced blacks. It renders a fuller palette of rich new colors, delivering a visual experience that engagesyour senses.Issue date 2023-03-23 Version: 7.0.212 NC: 8670 001 60105 EAN: 87 12581 75956 8© 2023 Koninklijke Philips N.V.All Rights reserved.Specifications are subject to change without notice. Trademarks are the property of Koninklijke Philips N.V. or their respective owners.SpecificationsPicture/Display•LCD panel type: VA LCD•Adaptive sync•Backlight type: W-LED system•Panel Size: 43.4 inch / 110.2 cm•Display Screen Coating: Anti-Glare, 2H, Haze 25%•Effective viewing area: 1052.3 (H) x 328.8 (V) mm - at a 1800R curvature*•Aspect ratio: 32:10•Maximum resolution: 3840 x 1200 @ 100 Hz*•Pixel Density: 93 PPI•Response time (typical): 4 ms (Gray to Gray)*•Brightness: 450 cd/m²•Contrast ratio (typical): 3000:1•SmartContrast: 80,000,000:1•Pixel pitch: 0.274 x 0.274 mm•Viewing angle: 178º (H) / 178º (V), @ C/R > 10•Picture enhancement: SmartImage•Display colors: Color support 1.07 billion colors •Color gamut (min.): BT. 709 Coverage: 99%*, DCI-P3 Coverage: 95%*•Color gamut (typical): NTSC 105%*, sRGB 123%*, Adobe RGB 91%*•HDR: DisplayHDR 400 certified (DP / HDMI)•Scanning Frequency: 30 - 150 kHz (H) / 48 - 100 Hz (V)•SmartUniformity: 93 ~ 105%•Delta E: < 2 (sRGB)•sRGB•Flicker-free•LowBlue Mode•EasyReadConnectivity•Signal Input: DisplayPort 1.4* x 2; HDMI 2.0b x 1; USB-C 3.2 Gen 1 x 2 (upstream, power delivery up to 90W)•HDCP: HDCP 2.2 (HDMI / DP), HDCP 1.4 (USB-C)•USB:: USB-C 3.2 Gen 1 x 2 (upstream), USB 3.2 x 4 (downstream with 1 fast charge B.C 1.2)•Audio (In/Out): Headphone out•RJ45: Ethernet LAN up to 1G*•Sync Input: Separate SyncUSB•USB-C: Reversible plug connector•Super speed: Data and Video transfer•DP: Built-in Display Port Alt mode•Power delivery: USB PD version 3.0•USB-C max. power delivery: Up to 90W* (5V/3A; 7V/3A; 9V/3A; 10V/3A;12V/3A; 15V/3A; 20V/3.75A; 20V/4.5A)Convenience•Built-in Speakers: 5 W x 2•Built-in webcam: Pop-up 2.0 megapixel FHD camera with microphone and LED indictor (for Windows 10 Hello)•MultiView: PBP (2x devices)•User convenience: SmartImage, Input, User, Menu, Power On/Off•Control software: SmartControl•OSD Languages: Brazil Portuguese, Czech, Dutch,English, Finnish, French, German, Greek,Hungarian, Italian, Japanese, Korean, Polish,Portuguese, Russian, Simplified Chinese, Spanish,Swedish, Traditional Chinese, Turkish, Ukrainian•Other convenience: Kensington lock, VESA mount(100x100mm)•Plug & Play Compatibility: DDC/CI, Mac OS X,sRGB, Windows 10 / 8.1 / 8 / 7Stand•Height adjustment: 130 mm•Swivel:-/+20 degree•Tilt: -5~10 degreePower•ECO mode: 36.2 W (typ.)•On mode: 41.8 W (typ.) (EnergyStar 8.0 testmethod)•Standby mode: 0.4 W (typ.)•Off mode: Zero watts with Zero switch•Energy Label Class: G•Power LED indicator: Operation - White, Standbymode- White (blinking)•Power supply: Built-in, 100-240VAC, 50-60HzDimensions•Product with stand(max height): 1058 x 560 x303 mm•Product without stand (mm): 1058 x 361 x137 mm•Packaging in mm (WxHxD): 1150 x 525 x 350 mmWeight•Product with stand (kg): 14.37 kg•Product without stand (kg): 10.34 kg•Product with packaging (kg): 20.19 kgOperating conditions•Temperature range (operation): 0°C to 40 °C•Temperature range (storage): -20°C to 60 °C•Relative humidity: 20%-80 %•Altitude: Operation: +12,000ft (3,658m), Non-operation: +40,000ft (12,192m)•MTBF (demonstrated): 70,000 hrs (excludedbacklight)Sustainability•Environmental and energy: EnergyStar 8.0,EPEAT*, TCO Certified, RoHS, WEEE•Recyclable packaging material: 100 %•Post consumer recycled plastic: 35%•Specific Substances: PVC / BFR free housing,Mercury freeCompliance and standards•Regulatory Approvals: CE Mark, FCC Class B,UKRAINIAN, ICES-003, CU-EAC, TUV/GS, TUVErgoCabinet•Front bezel: Black•Rear cover: Black•Foot:Black•Finish: TextureWhat's in the box?•Monitor with stand•Cables:HDMI cable,DP cable, USB-C to C/A,Power cable•User Documentation*Radius of the arc of the display curvature in mm*The maximum resolution works for either USB-C, DP or HDMIinput.*Response time value equal to SmartResponse*BT. 709 / DCI-P3 Coverage based on CIE1976*NTSC Area based on CIE1976*sRGB Area based on CIE1931*Adobe RGB Coverage based on CIE1976*DisplayPort 1.4 version is for HDR*Activities such as screen sharing, on-line streaming video and audioover the Internet can impact your network performance. Yourhardware, network bandwidth and its performance will determineoverall audio and video quality.*For USB-C power and charging function, your Notebook/devicemust support USB-C standard Power Delivery specifications. Pleasecheck with your Notebook user manual or manufacturer for moredetails.*For Video transmission via USB-C, your Notebook/device mustsupport USB-C DP Alt mode*USB-C max. power delivery: 1st USB-C port can support to 75 Wand 2nd USB-C port can support to 15 W.*If your Ethernet connection seems slow, please enter OSD menuand select USB 3.0 or higher version which can support the LANspeed to 1G.*EPEAT rating is valid only where Philips registers the product. Pleasevisit https:/// for registration status in your country.*The monitor may look different from feature images.。
nativealloc concurrent copying gcfreedNativeAlloc Concurrent Copying GC Freed是一个Android中的垃圾回收机制,用于回收Java heap中未使用的内存。
本文将会详细介绍该机制的工作原理以及如何优化其性能。
第一步,我们需要了解Java Heap的结构。
Java Heap是Java虚拟机最大的一块内存区域,主要用于存储对象实例。
Java Heap可以被划分为年轻代和老年代两部分。
年轻代又可以被分为eden space、survivor space 0和survivor space 1三个区域。
Java虚拟机的垃圾回收机制主要针对年轻代和老年代进行回收。
第二步,我们介绍一下“Concurrent Copying GC”算法。
这是一种基于“分代假说”的垃圾回收算法,它将Java Heap划分为年轻代和老年代两部分。
年轻代又被划分为eden space和两个survivor space。
当年轻代的eden space被填满后会触发一次垃圾回收,此时所有存活的对象会被复制到survivor space中。
当survivor space也被填满后,会发生Minor GC,将存活的对象复制到另一个survivor space中。
第三步,我们讨论一下NativeAlloc。
NativeAlloc是一种在Native内存池中分配内存的机制。
由于Native内存池不受Java虚拟机的管理,因此在使用NativeAlloc时需要特别小心,以避免内存泄漏和未定义的行为。
第四步,我们来谈谈如何优化NativeAlloc Concurrent Copying GC Freed机制的性能。
首先,尽量避免使用NativeAlloc,除非必要情况下才使用。
其次,在使用Java Heap时尽量使用比较小的对象,以减少内存占用。
接着,尽量避免创建过多的对象,可以使用对象池的方式来减少内存占用。
adaptivethreshold 偏移量-回复什么是adaptivethreshold 偏移量?Adaptivethreshold 偏移量(Adaptive Threshold Offset)是一种图像处理中常用的技术,用于将图像分割为二值图像。
图像分割是图像处理的基础步骤之一,它将图像中的目标和背景分离出来,使得图像更容易理解和处理。
在进行图像分割时,常常需要选择一个合适的阈值来确定目标和背景,而adaptivethreshold 偏移量就是用来计算这个阈值的。
为了更好地理解adaptivethreshold 偏移量的作用,首先需要了解adaptivethreshold 分割算法的工作原理。
这一算法是基于自适应阈值的分割方法,它可以根据图像中的像素灰度值的局部特性自动选择阈值,从而实现更好的分割效果。
adaptivethreshold 分割算法根据像素周围的邻域信息来确定每个像素的阈值,这使得它能够在受到光照和噪声等因素影响时仍能有效地进行图像分割。
具体而言,adaptivethreshold 偏移量是用来调整adaptivethreshold 算法中的阈值的。
adaptivethreshold 算法根据图像局部邻域的平均灰度值来计算阈值,而adaptivethreshold 偏移量可以对这个计算结果进行修正。
当我们在使用adaptivethreshold 算法进行图像分割时,可能会遇到一些特殊情况,例如图像中存在很强的光照差异或者噪声干扰较多。
这些情况下,adaptivethreshold 的计算结果可能会偏离我们期望的分割效果,因此我们需要根据实际情况调整阈值。
adaptivethreshold 偏移量可以通过增加或减少adaptivethreshold 算法中的阈值来实现。
当图像中存在较强光照差异时,我们可以增加偏移量来使得阈值增加,从而更好地适应光照变化。
而当图像中存在噪声干扰时,我们可以减少偏移量来使得阈值减小,从而更好地保留目标的细节信息。
,Manfred K.Warmuth,Scott A.Brandt,Ismail Arirbgramacy,manfred,scott,ari@University of California Santa CruzAbstractWe are constructing caching policies that have13-20%lower miss ratesthan the best of twelve baseline policies over a large variety of requeststreams.This represents an improvement of49–63%over Least RecentlyUsed,the most commonly implemented policy.We achieve this not bydesigning a specific new policy but by using on-line Machine Learningalgorithms to dynamically shift between the standard policies based ontheir observed miss rates.A thorough experimental evaluation of ourtechniques is given,as well as a discussion of what makes caching aninteresting on-line learning problem.1IntroductionCaching is ubiquitous in operation systems.It is useful whenever we have a small,fast main memory and a larger,slower secondary memory.Infile system caching,the secondary memory is a hard drive or a networked storage server while in web caching the secondary memory is the Internet.The goal of caching is to keep within the smaller memory data objects(files,web pages,etc.)from the larger memory which are likely to be accessed again in the near future.Since the future request stream is not generally known,heuristics,called caching policies,are used to decide which objects should be discarded as new objects are retained.More precisely,if a requested object already resides in the cache then we call it a hit,corresponding to a low-latency data access.Otherwise,we call it a miss,corresponding to a high-latency data access as the data is fetched from the slower secondary memory into the faster cache memory.In the case of a miss,room must be made in the cache memory for the new object.To accomplish this a caching policy discards from the cache objects which it thinks will cause the fewest or least expensive future misses.In this work we consider twelve baseline policies including seven common policies (RAND,FIFO,LIFO,LRU,MRU,LFU,and MFU),andfive more recently devel-oped and very successful policies(SIZE and GDS[CI97],GD*[JB00],GDSF and LFUDA[ACD99]).These algorithms employ a variety of directly observable criteria including recency of access,frequency of access,size of the objects,cost of fetching the objects from secondary memory,and various combinations of these.The primary difficulty in selecting the best policy lies in the fact that each of these policies may work well in different situations or at different times due to variations in workload, system architecture,request size,type of processing,CPU speed,relative speeds of the0.10.20.30.40.50.60.70.8205000210000215000220000225000230000235000lru fifo mru lifo size lfu mfu rand gds gdsf lfuda gd 00.10.20.30.40.50.60.70.8205000210000215000220000225000230000(a)(b)205000210000215000220000225000230000235000Lowest miss rate policy switches between SIZE, GDS, GDSF, and GD*size gds gdsf gd 205000210000215000220000225000230000Lowest miss rate policy ... SIZE, GDS, GDSF, and GD*(c)(d)Figure 1:Miss rates (axis)of a)the twelve fixed policies (calculated w.r.t.a window of 300requests)over 30,000requests (axis),b)the same policies on a random permutation of the data set,c)and d)the policies with the lowest miss rates in the figures above.different memories,load on the communication network,etc.Thus the difficult questionis:In a given situation,which policy should govern the cache?For example,the requeststream from disk accesses on a PC is quite different from the request stream produced byweb-proxy accesses via a browser,or that of a file server on a local network.The relativeperformance of the twelve policies vary greatly depending on the application.Furthermore,the characteristics of a single request stream can vary temporally for a fixed application.For example,a file server can behave quite differently during the middle of the night whilemaking tape archives in order to backup data,whereas during the day its purpose is toserve file requests to and from other machines and/or users.Because of their differingdecision criteria,different policies perform better given different workload characteristics.The request streams become even more difficult to characterize when there is a hierarchyor a network of caches handling a variety of file-type requests.In these cases,choosing afixed policy for each cache in advance is doomed to be sub-optimal.The usual answer to the question of which policy to employ is either to select one thatworks well on average,or to select one that provides the best performance on some im-portant subset of the workload.However,these strategies have two inherent costs.First,the selection (and perhaps tuning)of the single policy to be used in any given situationis done by hand and may be both difficult and error-prone,especially in complex systemarchitectures with unknown and/or time-varying workloads.And second,the performanceof the chosen policy with the best expected average case performance may in fact be worsethan that achievable by another policy at any particular moment.Figure 1(a)shows the hitrate of the twelve policies described above on a representative portion of one of our datasets (described below in Section 3)and Figure 1(b)shows the hit rate of the same policieson a random permutation of the request stream.As can be clearly be seen,the miss rateson the permuted data set are quite different from those of the original data set,and it is thisdifference that our algorithms aim to exploit.Figures 1(c)and (d)show which policy isbest at each instant of time for the data segment and the permuted data segment.It is clearfrom these (representative)figures that the best policy changes over time.To avoid the perils associated with trying to hand-pick a single policy,one would like tobe able to automatically and dynamically select the best policy for any given situation.Inother words,one wants a cache replacement policy which is “adaptive”.In our SystemsResearch Group,we have identified the need for such a solution in the context of complex network architectures and time-varying workloads and suggested a preliminary framework in which a solution could operate[AAG ar],but without specific algorithmic solutions to the adaptation problem.This paper presents specific algorithmic solutions that address the need identified in that work.It is difficult to give a precise definition of“adaptive”when the data stream is continually changing.We use the term“adaptive”only informally and when we want to be precise we use off-line comparators to judge the performance of our on-line algorithms,as is com-monly done in on-line learning[LW94,CBFH97,KW97].A good adaptive on-line policy must do well compared to off-line comparators.In this paper we use two off-line compara-tors:BestFixed and BestShifting().BestFixed is the a posteriori selected policy with the lowest miss rate on the entire request stream for our twelve policies.BestShifting() considers all possible partitions of the request stream into at most segments of length up to along with the best policy for each segment.BestShifting()chooses the parti-tion with the lowest total miss rate over the entire dataset.The upper bounds and are necessary so that BestFixed()can be feasibly computed with dynamic programming. Off-line comparators that optimally partition the data stream are used extensively in the on-line learning community[LW94,HW98,BW02].For completeness,we also compare to the de facto standard policy,Least Recently Used(LRU).Rather than develop a new caching policy(well-plowed ground,to say the least),this paper uses a master policy to dynamically determine the success rate of all the other policies and switch among them based on their relative performance on the current request stream.We show that with no additional fetches,this policy works about as well as BestFixed.We define a refetch as a fetch of a previously seen object that was kept by the currently favored policy but was discarded from the real cache.With refetching,this policy can outperform BestFixed.In particular,when all required objects are refetched instantly,this policy has a13-20%lower miss rate than BestFixed,and almost the same performance as BestShift-ing.For reference,when compared with LRU,this policy has a49-63%lower miss rate. Disregarding misses on objects never seen before(compulsory misses),the performance improvements are even greater.Because the refetches are themselves potentially costly,it is important to note that they can be done in the background.Our preliminary experiments show this to be both feasible and effective,capturing most of the advantage of instant refetching.2The Master PolicyWe seek to develop an on-line master policy that determines which of a set of baseline policies should currently govern the real cache.Appropriate switch points need to be found and switches must be facilitated.Our key idea is“virtual caches”.A virtual cache simulates the operation of a single baseline policy.Each virtual cache records a few bytes of metadata about each object in its cache:ID,size,and calculated priority.The object data is only kept in the real cache,making the cost of maintaining the virtual caches negligible1.Via the virtual caches,the master policy can observe the miss rates of each policy on the actual request stream in order to determine their performance on the current workload.A simple heuristic for doing this is to continuously monitor the number of misses of each policy in a past window of,for example,1000requests.The master policy can give control of the real cache to the policy with the least misses in this window.While this works well in practice,maintaining such a window for manyfixed policies isexpensive.A better master policy keeps a single weight for each policy(non-negative and summing to one)which represents an estimate of its current relative performance.The master policy is always governed by the policy with the maximum weight2.Weights are updated by using the combined loss and share updates of Herbster and War-muth[HW98]and Bousquet and Warmuth[BW02]from the expert framework[CBFH97] for on-line learning.Here the experts are the caching policies.This technique is preferred to the window-based master policy because it uses much less memory,and because the parameters of the weight updates are easier to tune than the window size.This also makes the resulting master policy more robust(not shown).2.1The Weight UpdatesUpdating the weight vector after each trial is a two-part process.First,the weights of all policies that missed the new request are multiplied by a factorand then renormalized.We call thisthe loss update.Since the weights arerenormalized,they remain unchangedif all policies miss the new request.As noticed by Herbster and War-muth[HW98],multiplicative updatesdrive the weights of poor expertsto zero so quickly that it becomesdifficult for them to recover if theirexperts subsequently start doing well. Therefore,the second share update prevents the weights of experts that did well in the past from becoming0.20.40.60.81205000210000215000220000225000230000235000 FSUPWeightRequests Over TimeWeight History for Individual Policieslrufifomrulifosizelfumfurandgdsgdsflfudagd Figure2:Weights of baseline policies.too small,allowing them to recover quickly,as shown in Figure2.There are a number of share updates[HW98,BW02]with various recovery properties.Wechoose the F IXED S HARE TO U NIFORM P AST(FSUP)update because of its simplicityand efficiency.Note that the loss bounds proven in the expert framework for the combinedloss and share update do not apply in this context.This is because we use the mixtureweights only to select the best policy(discussion in full paper).However,our experimentalresults suggest that we are exploiting the recovery properties of the combined update thatare discussed extensively by Bousquet and Warmuth[BW02].Formally,for each trial,the loss update ismissØ ØwØo-0.100.10.20.30.40.50.6205000210000215000220000225000230000M i s s R a t e Requests Over Time Miss Rate Differences bestF - demd bestF - dfrd bestF - instFigure 3:BestFixed -P,where P Instantaneous,Demand,and Background Rollover .The higher the the more quickly past good policies will recover.In our experiments weusedand .2.2Demand vs.Instantaneous RolloverWhen space is needed to cache a new request,the master policy discards objects not present in the governing policy’s virtual cache 3.This causes the content of the real cache to “roll over”to the content of the current governing virtual cache.We call this demand rollover because objects in the governing virtual cache are refetched into the real cache on demand.While this master policy works almost as well as BestFixed,we were not satisfied and wanted to do as well as BestShifting.We noticed that the content of the real cache lagged behind the content of the governing virtual cache and had more misses.As a consequence,the miss rate of the master policy was greatly improved if,as soon as we switched over to a new governing policy,we refetched all the files in that policy’s virtual cache that were not retained in the real cache.We call this instantaneous rollover .By appropriate tuning of the update parameters and ,the number of instantaneous rollovers can be kept reasonablysmall and the miss rates of our master policy are almost as good as BestShifting().Here an upper bound for is chosen (generously)to be twice the number of rollovers used by our master policy,and is set to the maximum segment length.2.3Background RolloverBecause instantaneous rollover immediately refetches everything in the governing virtual cache that is not already in the real cache,it may cause a large number of refetches even when the number of policy switches is kept small.If all refetches are counted as misses,then the miss rate of such a master policy is comparable to that of BestFixed.The same is true for BestShifting.However,from a user perspective,refetching is advantageous be-cause of the latency advantage gained by having required objects in memory before they are needed.And from a system perspective,refetches can be “free”if they are done when the system is idle.To take advantage of these “free”refetches,we introduce the concept of background rollover .The exact criteria for when to refetch each missing object will depend heavily on the system,workload,and expected cost and benefit of each object.To characterize the performance of background rollover without addressing these architectural details,the following background refetching strategies were examined:1refetch for every cache miss;1for every hit;1for every request;2for every request;1for every hit and 5for every miss,etc.Each background technique gave fewer misses than BestFixed,approach-ing and nearly matching the performance obtained by the master policy using instantaneous0.10.20.30.40.50.60.70.8205000210000215000220000225000230000235000M i s s R a t e s Requests Over Time Miss Rates under FSUP with Master lru fifo mru lifo size lfu mfurand gds gdsf lfuda gd roll Figure 4:“Tracking”the best policy.Figure 5:Miss rates of BestFixed,Demand,Back-ground,Instantaneous,and BestShifting.Works Server Week Month LRU #Requests 138k 48k Cache size 900KB 4MB %Skipped 6.5%15.7%#Compuls 0.0200.152#Shifts 8893LRU Miss Rate 0.0880.450GDS 0.07554.7%DemandMiss Rate0.0610.450%BestF-9.6%-12.8%%LRU 30.9%48.5%0.0689.8%59.4%Backgrnd 2Miss Rate0.0470.349%BestF15.4%12.4%%LRU 46.6%60.3%0.06513.4%60.8%BestShiftingMiss Rate0.0420.312%BestF23.6%21.8%%LRU 52.2%30.1%Figure 6:Performance Summary.rollover.Of course,techniques which reduce the number of policy switches (by tuning and )also reduce the number of refetches.Figure 3compares the performance of each master policy with that of BestFixed and shows that the three master policies almost always outperform BestFixed.3Data and ResultsFigure 4shows how the master policy with instantaneous rollover (labeled ’roll’)“tracks”the baseline policy with the lowest miss rate over the representative data segment used in previous figures.Figure 5shows the performance of our master policies with respect to BestFixed,BestShifting,and LRU.It shows that demand rollover does slightly worse than BestFixed,while background 1(1refetch every request)and background 2(1refetch every hit and 5every miss)do better than BestFixed and almost as well as instantaneous,which itself does almost as well as BestShifting.All of the policies do significantly better than LRU.Discounting the compulsory misses,our best policies have 1/3fewer “real”misses than BestFixed and 1/2the “real”misses of LRU.Figure 6summarizes the performance of our algorithms over three large datasets.These were gathered using Carnegie Mellon University’s DFSTrace system [MS96]and had durations ranging from a single day to over a year.The traces we used represent a variety of workloads including a personal workstation (Work-Week),a single user (User-Month),and a remote storage system with a large number of clients,filtered by LRU on the clients’local caches (Server-Month-LRU).For each data set,the table shows the number of requests,%of requests skipped (sizecache size),number of compulsory misses of objects not previously seen,and the number of rollovers.For each policy,the table shows miss rate,and %improvement over BestFixed(labeled ’BF’)and LRU.4ConclusionOperating systems have many hidden parameter tweaking problems which are ideal appli-cations for on-line Machine Learning algorithms.These parameters are often set to values which provide good average case performance on a test workload.For example,we have identified candidate parameters in device management,file systems,and network proto-cols.Previously the on-line algorithms for predicting as well as the best shifting expert were used to tune the time-out for spinning down the disk of a PC[HLSS00].In this pa-per we use the weight updates of these algorithms for dynamically determining the best caching policy.This application is more elaborate because we needed to actively gather performance information about the caching policies via virtual caches.In future work we will do a more thorough study of feasibility of deferred rollover by building actual sys-tems using the algorithms we investigated in the simulations described in this paper.We will also explore the relationship of our methods to reinforcement learning and multi-arm bandit problems.Acknowledgements:Thanks to Jonathan Panttaja,Ahmed Amer,and Ethan Miller for their contributions to this research.References[AAG ar]Ismail Ari,Ahmed Amer,Robert Gramacy,Ethan Miller,Scott Brandt,and DarrellD.E.Long.ACME:Adaptive caching using multiple experts.In Proceedings of the2002Workshop on Distributed Data and Structures(WDAS2002).Carleton Scientific,(to appear).[ACD99]Martin Arlitt,Ludmilla Cherkasova,John Dilley,Rich Friedrich,and Tai Jin.Eval-uating content management techniques for Web proxy 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