Utilization of Data Communication according to the IEC61850 Standard for Nuclear Power Pla
基于动态估计反馈的灰色理论航迹关联算法
第４６卷 第４期２０２４年４月系统工程与电子技术ＳｙｓｔｅｍｓＥｎｇｉｎｅｅｒｉｎｇａｎｄＥｌｅｃｔｒｏｎｉｃｓＶｏｌ．４６ Ｎｏ．４Ａｐｒｉｌ２０２４文章编号：１００１ ５０６Ｘ（２０２４）０４ １４０１ １１ 网址：ｗｗｗ．ｓｙｓ ｅｌｅ．ｃｏｍ收稿日期：２０２３０５２５；修回日期：２０２３０９１１；网络优先出版日期：２０２３１０２４。
网络优先出版地址：ｈｔｔｐ：∥ｋｎｓ．ｃｎｋｉ．ｎｅｔ／ｋｃｍｓ／ｄｅｔａｉｌ／１１．２４２２．ＴＮ．２０２３１０２４．１３３２．０１６．ｈｔｍｌ基金项目：国家自然科学基金（６１５０２５２２）资助课题 通讯作者．引用格式：邱建杰，蔡益朝，李浩，等．基于动态估计反馈的灰色理论航迹关联算法［Ｊ］．系统工程与电子技术，２０２４，４６（４）：１４０１ １４１１．犚犲犳犲狉犲狀犮犲犳狅狉犿犪狋：ＱＩＵＪＪ，ＣＡＩＹＣ，ＬＩＨ，ｅｔａｌ．Ｇｒｅｙｔｈｅｏｒｙｔｒａｃｋａｓｓｏｃｉａｔｉｏｎａｌｇｏｒｉｔｈｍｂａｓｅｄｏｎｄｙｎａｍｉｃｅｓｔｉｍａｔｉｏｎｆｅｅｄｂａｃｋ［Ｊ］．ＳｙｓｔｅｍｓＥｎｇｉｎｅｅｒｉｎｇａｎｄＥｌｅｃｔｒｏｎｉｃｓ，２０２４，４６（４）：１４０１ １４１１．基于动态估计反馈的灰色理论航迹关联算法邱建杰，蔡益朝 ，李 浩，黄权印（空军预警学院，湖北武汉４３００１４） 摘 要：针对传统基于灰色理论航迹关联算法未充分利用航迹历史信息，在密集目标以及时变噪声协方差等场景下关联正确率下降问题，在传统灰色分析法基础上增加了一种动态估计反馈机制。
改进后的算法引入了Ｓａｇｅ Ｈｕｓａ估计器来实时估计传感器的噪声协方差作为评估输出数据质量的依据，并使用Ｃｒｉｔｉｃ赋权法将实时噪声协方差转换为各时刻序贯权重，从而保证最大程度上的利用航迹历史信息。
仿真证明，在密集目标与时变噪声协方差等特殊关联场景下，所提算法明显优于传统灰色分析法以及模糊法、加权法等经典算法，充分证明了所提算法的性能优越性以及鲁棒性。
Victron Energy 数据通信协议选择指南说明书
IntroductionMany of our customers integrate our products into their own systems, using data communication protocols. There are several options to establish data communication. The purpose of this document is to explain the different options, and help you choose one.Communicating to a complete system? Use Modbus-TCPRather than going for direct communication with Inverters, battery monitors or Solar chargers, consider using ModbusTCP. This has two advantages:1.ModbusTCP is easier than most other protocols2.Retrieve precalculated system, as available on the Color Control GXLooking for internet related protocols? Use the JSON API or MQTTOnce uploaded to the VRM Portal by a Color Control GX, or another device running our Venus OS, the data can be requested via our VRM JSON API: https:///v2/docsBesides that API, MQTT is also available. More information here: https:///victronenergy/dbus-mqtt/blob/master/README.mdIntegrating into a Marine NMEA 2000 network? See our integration guide:https:///live/ve.can:nmea-2000:startMore informationAs a developer, make sure to also have a look at these three pages:1.An intro page of Victron Open source related work and pointers to various reading materials:https:///live/open_source:start2.The main wiki page of Venus OS, the OS that runs on our GX devices:https:///victronenergy/venus/wiki3.The Modifications section on our Community Forum. A forum where many developers help each other on ModbusTCP, MQTT, Node-Red,RaspberryPis, Grafana, Serial communication and many other topics.Products with data communicationThe following product lines have a data communication port, with protocol information available for 3rd parties: ArrayProtocol overviewVictron Energy B.V. | De Paal 35 | 1351 JG Almere | The Netherlands General phone: +31 (0)36 535 97 00 | E-mail: Page 2 of 13NMEA2000 Certified productsThis table lists all Victron products that have an NMEA2000 or VE.Can communication port, and the status of NMEA2000 certification. Note that theMake sure to read our NMEA 2000 & MFD integration guide: https:///live/ve.can:nmea-2000:startDetails per protocolVE.Can / NMEA2000Canbus is the preferred protocol for third parties to communicate with our products. Our CANbus protocol is based on the NMEA2000 and J1939 protocols.Further down in this document is a list per product with supported NMEA2000 PGNs. All data and settings that are not covered by the NMEA2000 standard PGNs are available through proprietary PGNs. More information is in the manuals of the Canbus-enabled products on our website, and in the document “VE.Can registers - public.docx”. Look for it on the Whitepapers page on our website.Detailed information on the NMEA2000 PGN’s is available for purchase on the NMEA website (). See the NMEA 2000® Appendix B POWER SUBSET.VE.DirectVE.Direct is a combination of what we used to call the HEX protocol and the BMV text protocol. It combines the advantages of both: in text-mode the products automatically transmit all important parameters every second. To implement code which reads and interprets this data is extremely simple. If more functionality is needed, such as changing settings, one can switch to the HEX protocol. Communication ports on new Victron products will always be either VE.Can or VE.Direct ports. The VE.Direct port is for products where a full Canbus connection adds to much cost. VE.Direct documentation is available on our website. Look for the VE.Direct Protocol document on: /support-and-downloads/whitepapers/. And see also the VE.Direct FAQ: https:///live/vedirect_protocol:faq.Victron Energy B.V. | De Paal 35 | 1351 JG Almere | The Netherlands General phone: +31 (0)36 535 97 00 | E-mail: Page 3 of 13Modbus TCPThe industry standard Modbus TCP is a well-known and open communication protocol, used in many PLCs and SCADA systems. The Victron Color Control GX acts as a Modbus-TCP gateway. Connect it to the Victron products that you want to monitor, and then communicate from your PLC to the Ethernet LAN port on the Color Control GX. It allows reading information, and writing operational parameters, such as Multi on/off and input current limiter settings. Changing configuration settings, such as battery capacity or float or absorption voltages, is not yet possible. Check the Color Control GX Datasheet to find out which products are supported by the Color Control GX.We use the default Modbus TCP port number, which is 502. The unit id, sometimes called ‘slave address’, specifies what product connected to the CCGX needs to be addressed. See the tab ‘Unit ID mapping’ in the Modbus-TCP excel sheet. The register addresses are listed on the first tab of the excel sheet, in column C. There are two data types, uint16 and int16. After receiving the value, divide it by the Scale factor to get the value in the unit as specified in column G.Download the list of registers from our website, look for the CCGX Modbus-TCP register list on /support-and-downloads/whitepapers/.The FAQ page as well as a commenting system to put questions is available on Victron Live: /live/ccgx:modbustcp_faqEthernet LAN switchVE.BusVE.DirectThe shown Multi and BMV are just an example. See Color Control datasheet for all compatible products.Victron Energy B.V. | De Paal 35 | 1351 JG Almere | The Netherlands Page 4 of 13VE.BusVE.Bus is our proprietary protocol used by the Inverters to synchronize their AC outputs. There are VE.Bus communication ports on our Inverters, Multi’s and Quattro’s. The synchronization feature is mission-critical. Direct third-party connections are not allowed. All interfacing has to be done via Modbus TCP (preferred), “VE.Bus to CANbus/NMEA2000 interface”, or via the MK2/MK3:MK2/MK3 ProtocolThe MK2.2 and MK3 provide a galvanically isolated connection to VE.Bus, and it translates the VE.Bus protocol into the “MK2/MK3 Protocol”. The MK2/MK3 Protocol allows reading information, turning the device on and off, changing the current limits and configuring a device. To download the document, look for the ‘Interfacing with VE.Bus products – MK2/MK3 protocol’ on: /support-and-downloads/whitepapers/Note that implementing the MK2/MK3 protocol is a task which is not to be underestimated. It is a complicated protocol, and unless there is a hugecommercial interest, we cannot give any support or help during the implementation(!). Make sure to have a look at Appendix 2 in that document, which is an annotated example for a typical UI.Note that there is no difference in protocol between the MK2 and MK3 interfaces.BMV-60xS Text Protocol (deprecated)All of our BMV-600’s feature a serial communication interface which allows simple access to detailed battery status information. This protocol only allows reading information from the battery monitor. Setting parameters or ‘synchronizing’ the BMV is not possible. Documentation is available on our website, look for the BMV60xS Text protocol: /support-and-downloads/whitepapers/. Note that this Text protocol is now part of the VE.Direct protocol. The successor of the BMV-600, the BMV-700, works with the VE.Direct protocol. See earlier in this document for more information on the VE.Direct protocol. (deprecated) is a proprietary protocol used by some of our control panels. Third party connections are not possible. New products will not be equipped with . They are equipped with VE.Can or VE.Direct instead.VE 9bit RS485 (deprecated)This protocol was used to communicate to our Multi’s and Quattro’s before they had paralleling and three phase capabilities. This protocol is no longer maintained. Documentation is not available.1 The Victron Interface MK2-USB is an MK2.2b with built-in RS232 to USB Converter.2 The Victron interface MK3-USB also has a built-in RS232 to USB Converter. There is no RS232 version of the MK3 available.3 The VE.Bus to VE.Can interface is the same as the VE.Bus to NMEA2000 interface. The only difference is the canbus connection. The VE.Bus to VE.Can interface has two RJ-45 sockets; the other one has the NMEA2000 Micro-c plug.4 The VE.Direct to VE.Can interface is the same as the VE.Direct to NMEA2000 interface. The only difference is the canbus connection. The VE.Direct to VE.Can interface has two RJ-45 sockets; the other one has the NMEA2000 Micro-c plug.5 Data, including historic data, can be accessed via https://. All data is stored in our database. Logs can be downloaded, see chapter “Getting the data from VRM”.Victron Energy B.V. | De Paal 35 | 1351 JG Almere | The Netherlands General phone: +31 (0)36 535 97 00 | E-mail: Page 5 of 13FAQ – GeneralQ1: Do I need an MK2 or MK3 for each product in a system with multiple VE.Bus products in parallel or three-phase? No. Per VE.Bus system you need only one of those interfaces.Q2: Do I need a VE.Bus to NMEA2000 interface for each product in a system with multiple VE.Bus products in parallel or three-phase? No. Per VE.Bus system you need only one of those interfaces.Q3. Why is it not possible that my application directly communicates with the Victron via VE.Bus messages?VE.Bus is our proprietary protocol used by the Inverters to synchronize their AC outputs. It is not possible to connect directly because as soon as other people are on that bus we cannot guarantee the proper working of paralleled and three-phase operations. Note that even in all our own display andcontrol products that talk to VE.Bus, for example the Color Control GX and the VE.Bus to NMEA2000 interface, we have an MK2/MK3 IC. So even at Victron we are not talking directly to VE.Bus.FAQ – Canbus communicationQ10: Which version of J1939 is actually implemented (J1939/11, J1939/15, J1939/14...)?We are using the NMEA2000 protocol, which is based on ISO 11783-3 (Datalink Layer) and ISO 11783-5 (Network management). ISO 11783-3 is virtually identical to the SAE data link layer SAE J1939-21. The network layer (ISO 1183-5) is based on SAE J1939-81. For more information, see also /content/nmea_standards/white_papers.asp . Q11: Is the bus speed 250kbps? Yes, the bus speed is 250kpbsQ12: Is the identifier extended (29-bits)?Yes, the ISO11783 standard defines the use of the extended identifier (29-bits). Q13: Are the data fields always 8 bytes long? Yes, the data fields are always 8 bytes long.Q14: Can you send us the PGN definition?This detailed documentation has to be bought from the NMEA website. You can buy the Power PGN’s at/store/index.asp?show=pdet&pid=322&cid=7. The product name is “NMEA 2000® Appendix B POWER SUBSET PGN (NMEA Network Messages) – Electronic”, USD 500,= for non-members. Note that for the VE.Bus AC messages you need some SAE documentation as well. More information on the used PGN’s is further down below in this document.Q15: Are all the messages broadcasted or do they have to be requested/polled?The important messages (AC status, Battery status, etc.) are broadcasted. Others have to be polled.Q16: Do I need to terminate the canbus?Yes you do. Use one 120Ohm 0,25W 5% resistor at both ends of the canbus. Connect it between CAN-H and CAN-L. Victron Energy sells a set of VE.Can terminators with part number ASS030700000.6 The Victron Global Remote has two communication ports. It can connect to a BMV and a VE.Bus product or system at the same time.7 The Victron Ethernet Remote has only one communication port, it can connect to one device.8Data can be accessed via a local, password secured, website, running on a web server in the Victron Ethernet Remote. Note that only the current values can be accessed. Historic data is not available on the local web server.Victron Energy B.V. | De Paal 35 | 1351 JG Almere | The Netherlands Page 6 of 13Q17: Do I need to power the canbus?That differs per product. Some products power the canbus themselves others don`t. To power the canbus, supply anywhere between 9 and 36Volts to V+ and V-. See also the pin outs below. A small list at the time of writing:Skylla-i Powers the canbus, isolated Skylla-IP44 Powers the canbus, non-isolated Lynx Shunt VE.Can Powers the canbus, isolated Lynx Ion BMS Powers the canbus, isolated Lynx Ion + Shunt Powers the canbus, isolated Lynx Ion Does not power the canbus, depends on the Lynx Shunt VE.Can to power both the VE.Can and the BMS canbus Color Control GX Does not power the canbus, and needs a powered canbus to operate VE.Bus to NMEA2000 interface Does not power the canbus, and needs a powered canbus to operate VE.Bus to VE.Can interface Does not power the canbus, and needs a powered canbus to operate BMV-60xS to NMEA2000 interface Does not power the canbus, and needs a powered canbus to operate VE.Direct to NMEA2000 interface Does not power the canbus, and needs a powered canbus to operate VE.Direct to VE.Can interface Does not power the canbus, and needs a powered canbus to operate BlueSolar MPPT 150/70 Does power the canbus, not isolated. See manual for info on a resistor that is mounted to prevent ground loops.The mentioned 9 to 36Volt is conform the NMEA2000 standards. Most of our products accept an input voltage from 7 to 70VDC, see the datasheets. Q18: What is the difference between NMEA2000 and VE.Can?The only difference is in the physical connection and the isolation: VE.Can NMEA2000 Physical connector RJ-45 Micro-C Isolation Differs per product, see Q17 above and/ordatasheetAlwaysQ19: What is the pin out of VE.Can?The two RJ-45 sockets on each product that has VE.Can are paralleled. Note that we use RJ-45 also for VE.Bus or connections, see the datasheet to make sure that your product has a VE.Can connection.added. The Skylla-i uses only pin 3 and 6 for power delivery. The Lynx Shunt VE.Can, as well as all later products, use pins 1, 2, 3 and 6. Q20: What is the pin out of NMEA-2000? Q21: I do not want to implement the full ACL procedure, what fixed source address shall I use?Address 0xFE is reserved for when you cannot perform an ACL (Address Claim) procedure. You are free to use this address. See also Q24. Q22: What is Victron’s NMEA2000 manufacturer code? It is 358 (0x166)NET-C / V- (see note below) NET-S / V+ (see note below)Victron Energy B.V. | De Paal 35 | 1351 JG Almere | The Netherlands General phone: +31 (0)36 535 97 00 | E-mail: Page 7 of 13Q23: Instances: I have multiple BMV’s (or another canbus product) in the same network, how do I address them?You need to use instances to differentiate between multiple similar products in the same network. There are different types of instances within NMEA2000:Device instanceThe device instance is sent in PGN 0xEE00, ISO Address Claim, as a combined field of Device Instance Lower (ISO ECU Instance) and Device Instance Upper (ISO Function Instance).The Device instance is used by Victron chargers (Skylla-i/-IP44, VE.Can MPPTs) to configure them in the same group and synchronize them.Data instances (Battery Instance, DC Detailed Instance, Switch bank instance, etc.)These instances are embedded in the different PGN’s. All Victron products support changing these instances through a complex write, PGN 0x1ED00, Complex Request Group Function Code 5, write fields.System instanceThe system instance is also sent in PGN 0xEE00, field 8. It is not used. All Victron products do support changing this instance by sending a complex command.Instance conflictsIf you have connected multiple products sending out the same PGN with the same data instance number, you might encounter a data instance conflict. Typically this can be seen on display’s showing an alternating value. E.g. The VE.Direct to NMEA2000 interface and VE.Bus to NMEA2000 interface are both sending out PGN 127508 with Battery instance 0. To solve this issue one of the Battery instances needs to be changed to another (unique) number. We recommend to change the Battery instance of the VE.Bus to NMEA2000 instance to 5.More information about changing instances is here: /documentation/ve.can:changing_nmea2000_instances .Display manufacturersThe display manufacturers may use different types of instances to show data for multiple batteries, inverters or chargers. For more information about MFD integration, please visit https:///live/ve.can:nmea-2000:start .Q24: Do the Victron VE.Can and NMEA2000 products used fixed network address or do they support NMEA address claim ISO 602928? All our products have implemented the address claim procedure. See also Q21.Q25: I want to read the State of Charge (0 to 100%) as calculated by the Multis and Quattros. I do understand that this SOC is only reliable if there are no DC loads or other battery chargers in the system (almost impossible on a boat, but in a self-consumption system this is very possible). And I cannot find the SOC in the PGNs.Correct, the information is in PGN 127506, but transmission of that PGN is disabled by default, because it is not valid in all systems. To enable transmission of this PGN, change the transmission interval. To do this at protocol level, see NMEA2000 documentation, PGN 126208 - NMEA - Request group function (field 1 = 0x00). And then field 3, transmission interval. To do this at PC level, use Actisense NMEA Reader or other PC software that has this functionality.Q26: Which products have a bag of VE.Can RJ-45 terminators included? These products are shipped with two pieces of VE.Can RJ-45 terminators:- Color Control GX - MPPT 150/70 and MPPT 150/85 Solar Charge Controllers - Lynx Ion + Shunt all models - Lynx Ion BMS all models - Lynx Shunt VE.Can - VE.Bus to VE.Can interface - VE.Direct to VE.Can interface - Skylla-i control - CANUSBThese products are shipped without:- Ion Control (not necessary since terminators are included with the Lynx Ion + Shunt) - BMV-60xS to VE.Can interface - VE.Can to NMEA2000 Micro-C male cable - VE.Can resistive tank sensor (not necessary, terminators are included with the CCGX)Note that it will normally not be necessary to purchase the terminators separately.Victron Energy B.V. | De Paal 35 | 1351 JG Almere | The Netherlands Page 8 of 13Canbus PGN overview per productUse below tables to see where to find what data. There is a freely available PDF file on the NMEA2000 website that also gives a good overview. Go to /content/nmea_standards/downloads.asp , and then the link called “NMEA2000 Parameter Group Descriptions (Messages) with Field Description”. To get the detailed information in order to decode the PGNs, see Q14 in the FAQs.(field 1) are the same number. Changing one of the instances will change all of the mentioned instances.See the VE.Bus to NMEA2000 interface manual for more details (https:///accessories/ve-bus-to-nmea2000-interface ). Note that the Skylla-i/-IP44 will switch off when there is no mains available. It will therefore also stop sending and responding to Canbus messages.9The AC Input Status PGN 127503 is not present on the Skylla-IP44Victron Energy B.V. | De Paal 35 | 1351 JG Almere | The Netherlands General phone: +31 (0)36 535 97 00 | E-mail: Page 9 of 13The Battery instance for PGNs 127508 can be changed. After you did that, you can still distinguish between the Battery and PV information by looking at the DC detailed status PGN, 127506 0x1F212. It will report the DC Type, field 3, as Battery or Solar Cell. Field 2, DC Instance, equals the Battery instance in the Battery Status PGN for battery and solar information.• Battery instance 0 and DC Instance 0 are the same instance number, only the name is different in the NMEA2000 documentation.• Above table is valid for the latest firmware version of the VE.Direct to NMEA2000 interface cable, v1.06. Previous firmware versions used PGN127502 instead of 127501 to report relay and alarm status.See the manual of the VE.Direct to NMEA2000 Interface for more details (https:///accessories/ve-direct-to-nmea2000-interface ).•Both the Lynx Ion and the Lynx Shunt VE.Can are sending Battery pack voltage and Battery pack current. Distinction can only be made on product id.•Battery instance 0 and DC Instance 0 are the same•One or more 24V 180Ah batteries together in one system are a Battery pack.•One 24V 180Ah battery, consisting of 8 cells is a Battery.Page 10 of 13 Victron Energy B.V. | De Paal 35 | 1351 JG Almere | The NetherlandsVictron Energy B.V. | De Paal 35 | 1351 JG Almere | The Netherlands General phone: +31 (0)36 535 97 00 | E-mail: *********************** Page 11 of 13DEPRECATED: Getting data from VRM with wgetUse the JSON API for this, instead of wget. See: https:///v2/docsDEPRECATED: VRM Juice APIUse the new JSON VRM API, instead of Juice. See https:///v2/docsLinks to interesting productsNote that we have not tested all these products, and they are not affiliated to Victron Energy in any way. We do not take any responsibility. Consider using our own Color Control GX as the Victron to ModbusTCP converter, instead of below products.1.NMEA2000 to Modbus RS485 converter by Offshore Systems (UK) Ltd:/3155.htm2.Converters from NMEA2000 to a variety of protocols, one of them is Modbus:/home/products/NMEA2000_Conveters.asp?frompg=nav14_23.RS232 to Ethernet/LAN Converter. Works well with the BMV Text Protocol. With the MK2/MK3 Protocol it is not very stable. The ATOP SE5001-S2/en/productList2.php?pl1_id=2Victron Energy B.V. | De Paal 35 | 1351 JG Almere | The Netherlands General phone: +31 (0)36 535 97 00 | E-mail: *********************** Page 12 of 13Document HistoryVictron Energy B.V. | De Paal 35 | 1351 JG Almere | The Netherlands General phone: +31 (0)36 535 97 00 | E-mail: *********************** Page 13 of 13。
与物联网相关的专业词汇
与物联网相关的专业词汇1.物联网Internet of Things2.体系结构architecture3.连接模式interconnection model4.通信协议communication protocol5.服务机制service mechanism6.信息模型information model7.物品关联thing association8.信息感知information sensing9.信息交互information interaction10.无线传感器网络wireless sensor network11.传感仪器sensing instrument12.光谱Spectrum13.系统架构architecture of IoT14.协议体系protocol structure15.时空数据spatial-temporal data16.海量数据管理 massive data management17.数据库集群系统database cluster system18.数据挖掘data mining19.电子饲喂站electronic feeding station20.信息采集系统 information acquisition system21.上下文感知context-aware22.服务质量QoS23.语义标注semantic annotation24.可信计算trusted computing25.匿名认证anonymous authentication26.匿名传输anonymous transmission27.无线射频识别 Radio Frequency Identification（RFID）28.农业物联网agriculture Internet of Things29.设施农业facility agriculture30.服务推荐service recommendation二、我感兴趣的一些专业词汇31.大数据big data32.深度学习deep learning33.社会计算social computing34.可视化visualization35.数据可用性data usability36.流式计算stream computing37.内存计算memory computing38.非结构化数据 unstructured data39.社交网络数据 social network data40.云计算技术cloud computing41.自然语言处理 natural language processing42.自然语言理解 natural language understanding43.贝叶斯推理Bayesian inference44.主题模型topic model45.机器翻译machine translation46.聚类分析clustering analysis47.词频分析frequency analysis48.主题词提取topic words extraction49.人工智能artificial intelligence50.混合模型hybrid model。
通信英语(第四版)张筱华_石方文_北京邮电大学出版社【课后习题答案】
1.PCM原理抽样量化与编码:sampling,quantizing and coding话路:speech channel幅值: amplitude value抽样频率: sampling frequency抽样速率: sampling rate脉冲流: stream of pulses重复率: repetition rate编码过程: coding process模拟信号: analog signal传输质量: transmission quality数字通信: digital communication数字传输: digital transmission含噪声的环境: noisy environment传输路由: transmission path信噪比 :signal-to-noise ratio信号电平 :signal levels噪声功率: noise power地面系统: terrestrial system二进制传输: binary transmission反向操作: reverse operation8-位码序列: 8-digit sequence接受端: receiving terminal帧格式 :frame format同步字 :synchronization word实现这三项功能的方案 :the schemes for performing these three functions一串幅值: a series of amplitude values电话质量的话路 a speech channel of telephone quality一个8位二进制码的序列: a sequence of 8-binary digits理论上的最小抽样频率 :a minimum theoretical sampling frequency占据着300Hz到3.4kHz频率范围的话路: a voice channel occupying the range 300Hz to 3.4kHz 每个样值8-位码: 8-digits per sample value汽车点火系统的打火: the sparking of a car ignition system重复率为64kHz的脉冲流: the stream of the pulses with a repetition rate of 64kHz真实信号与噪声信号的关系: relationship of the true signal to the noise signal由卫星上接受到的信号 :the signal received from a satellite一条特定消息中的全部信息 :the complete informatian about a particular message被传信号的波形 :the shape of the transmitted signal由传输路由引入的衰减: the attenuation introduced by transmission path将抽样的幅值转换成一串脉冲的单元 :the unit that converts sampled amplitude value to a set of pulses涉及到第一路，第二路及其他各路的序列: a sequence relating to channel 1,2 and so on被称为同步字的独特码序列: a unique sequence of pulses called synchronization word地面系统 :terrestrial system脉冲的“有”或“无” : the presence or absence of the pulses高速的电子开关: a high-speed electronic switch时分多路复用器 :the time division multiplexer时分多路复用 :Time Division Multiplexer2.异步串行数据传输串行接口 serial interface显示终端 CRT terminal发送器与接收器 transmitter and receiver数据传输 data transmission数据流 data stream闲置状态 the idle state传号电平 mark level空号电位 space level起始位 start bit停止位 stop bitT秒的持续时间 duration of T seconds奇偶校检位 parity bit错误标志 error flag传输错误 transmission error下降沿 fallinf edge符号间的空格 intersymbol space接收机的定时 receiver timing本地时钟 local clock磁带 magnetic tape控制比特 control bit逻辑1电平 logical 1 level二进制数据 binary data明显的缺点 obvious disadvantage异步串行数据传输 asynchronous serial data transmission最为流行的串行接口 the most popular serial interface所传送的数据 the transmitted data发送器与接收器的时钟 the clocks at the transmitter and receiver电传机的时代 the era of teleprinter一个字符的点和划 the dots and dashs of a character符号间空格持续时间的三倍 three times the duration of intersymbol space被称为字符的比特组 the group of bits called characters由7或8个比特的信息组成的固定单元 the invariable units comprising 7 or 8 bits of information 由接收机本地产生的时钟 a clock generated locally by the receiver在字符后所收到的奇偶校检位 the received parity bit following the character起始位的下降沿 the falling edge of the start bit数据链路面向字符的特性 the character-oriented nature of the data link3.数据通信地下电缆 underground cable通信卫星 communication satellite微波设备 microwave facilities调制器与解调器 modulator and demodulator缓冲器 buffer定时信号 timing signals同步脉冲 synchronization pulses时隙 time slot移位寄存器 shift register传输媒体 transmission medium线形衰弱 linear attenuation信息安全 information security键盘 keyboard数据终端 data terminals某种类型的数据转换设备 some type of data conversion equipment视频显示终端 visual display terminal称为数据调制解调器的双向数据发送接收机 two-way data transmistter-receiver called a data modem 全双工的数据传输系统 full-duplex data trandmission system由数据处理器的运算速率所决定的速率 the rate determined by the operating speed of the data processor由接口部件来的定时信号 timing signals from the interface assembly磁心存储器 magnetic core memories线性衰减和时延特性 linear attenuation and delay characteristics传输损伤 transmission impairments语音中的冗余特性 the redundant nature of speech在数据发送器中的编码过程 coding process in the data transmitter二进制的不归零信号 binary nonreturn-to-zero signal4.互联网网络资源：network resource信息服务：information services远程终端：remote terminals互联的系统：interconnected systems命令：command电子邮件：electronic mail主机：host无线信道：wireless channels搜索工具：searching tools用户界面：user interface存取：access文本信息：textual messages协议：protocol超文本协议：hypertext protocol分布在全世界的计算机的巨大网络：gaint network of computers located all over the world主干系统：backbone system全国范围的网络：nationwild network电子会议：electronic conferences实时对话：live conversation最大的信息库the largest repository of the computers on the net网络设备资源：network facilities resources在网上的绝大多数计算机：the vast majority of the computer on the netUNIX操作系统：the UNIX operating system在因特网和你的PC机之间传送数据的方法：a way to move data between the internet and your PC 方便的搜索工具：the convenient searching tools联网的超文本协议：the network hypertext protocol5.光纤通信介绍光纤通信:optical fiber communications光源：light source波长：wavelength激光器：laser色散：dispersion传输介质：transmission medium多模光纤：multi-mode fiber长途干线：long-houl trunks单模光纤：singer-mode fiber带宽：bandwidth带宽用户：wideband subscriber纤维光学：fiber-optics商用技术：commercial technologe门限电流：threshod current光检测器：photodetector波分复用：wavelength multiplexing纤维光网络：fiber-optic network视频带宽：video bandwidth长途传输：long distance transmission中继距离：repeater spacing已装光纤的总长度：the total length of installed fiber长途通信系统：long-haul telecommunication system低衰减的石英纤维：the low-loss silica fiber衰减接近瑞利极限的光纤：fibers with losses approaching the Rayleigh limit室温下的门限电流：room temperature threshold currents较长波长区：the longer wavelength region用户接入工程：subscriber access project部件性能和可靠性的改进：improvements in component performance and reliability已安装的光纤系统的数据速率：data rates for installed fibre optic system每秒吉比特：gigabit per second range波分复用：wavelength multiplexing带宽用户环路系统：widebend subscriber loop system多纤连接器：multifibre connectors设计寿命：projected lifetime光源：light source单模光纤：single-mode fibre分布反馈式激光器：distributed-feedback laser信息容量：information capacity交换体系：switching hierarchy带宽业务：broadband services6.同步数字系列同步数字系统：synchronous digital hierarchy国际标准：international standard信号格式：signal format网络节点接口：network node interface支路信号：tributary signals数字交叉连接：digital cross-connection网络管理：network management网络维护：network maintenance网络运营者：network operators传输速率：transmission rate支路映射：tributary mapping灵活性：flexibility用户业务：subscriber services覆盖层：overlay levels制造商：manufacturer同步传输帧：synchronous transmission frame线路终端复用器：line terminal multiplexer分插复用器：add-drop multiplexer再生中继器：regenerator灵敏度：sensitivity虚容器：virtual container成帧字节：framing bytes段开销：section overhead端到端传输：end-to-end transmission误码监视：error monitoring信号处理节点：signal processing nodes净负荷：payload指针：pointer同步传输系统：synchronous transmission system覆盖nni的标准：the standard covering the NNI国际标准接口：the international standard interface直接同步复用：direct synchronous multiplexing灵活的通信联网：flexible telecommunication networking点对点的传输技术：point-to-point transmission technology先进的网络管理：advanced network management不同厂家提供的设备：the equipment supplied by different manmufacturers SDH提供的灵活性：the flexibility provided by SDH同步复用设备的运营者：operator of synchronous multiplexers电信联网：telecommunication networking支路信号：tributary signals维护能力：maintenance capabilities统一的电信网络基础结构：unified telecommunication network infrastructure 组件：building blocks终端复用器：terminal multiplexer贯通方式：through-mode fashion同步数字交叉链接：synchronous DXC可变带宽：arying bandwidth各个支路信号：individual tributary signals传输系统：transport system光载体：optical carrier二维图形：2-dimensional map传输次序：the order of transmission7.波分复用对光特性的理解：the understanding of the property of light基本重要性：the fundamental important想象今天的通信系统：to imagine the communication system of today光的高速公路：the highway of light巨量的信息：the massive amount of information采用通信新技术：to adopt new communication technology大量的视频信息：the large amounts of video information波分复用：the wave divide multiplexing只发送单个波长：to send only one wavelength传输大量的波长：to transmit a large amount of wavelength无差错传输：the error-free transmission自愈特性：the self-healing propertys直接接入光网络：to access directly to the optial network视频信息：the video information导致WDM革命的主要进展：the major advance that led to the revolution光放大器的发明：the invention of the optical amplifier下一段光纤：the next span of fiber提高所有波长信号的功率：to boost the signal power of all wavelength在光放大器方面的进展：the advances in optical amplifier增益均衡技术的发展：the development of gain equalization techniques多波长传输：the multiple-wavelength transmission无线系统的增长：the growth of various application各种各样的业务：the wide various application处理各种业务类型：to handle various types of traffic全光交叉连接：the all-optical cross-connect8.寻呼系统的发展通信手段：communication means被叫人：called person紧急通信：urgent communications移动电话网：mobile telephone network电话交换台：telephone switchboard寻呼业务：paging service电子电路：electronic circuitry无线传输：wireless transmission无线发射机：wireless transmitter个人代码：personal codes服务区：service area单向通信：one-way communication寻呼用户：paging users顾客：customer技术进步：technological progress系统的效率：efficiency of the system专用的无线网络：dedicated wireless network终端设备：terminal equipment全球覆盖：global coverage无线增益：gain of the antenna空间站：space station通信网络的运行：the operation of a communication network有线的和移动的电话网络：the wired and mobile telephone network光和声音的信号装置：optical and acoustical signaling devices本地电话交换台的接线员：the operator of a local telephone switchboard 第一代寻呼系统：the first generation of paging system利用无线传输的寻呼系统：the paging system using wireless transmission 专用的无线接收机：the dedicated radio receiver社会和经济效益：social and economic advantages电子电路的小型化：the miniaturization of electronic circuitry价格效率比：cost efficiency小型无线电接收机：the miniature radio receiver显示能力：display capability全球覆盖：global coverage空间站的天线增益：the space station antenna gain地球同步轨道卫星：geostationary orbit satellite用户终端：user terminal9.蜂窝式移动电话系统蜂窝式移动电话：cellular mobile telephone服务性能：services performance频谱：frequency spectrum频带：frequency band微处理器：microprocessor移动手机：mobile unit广播业务：broadcast servise天线：antenna子系统：subsystems移动用户：mobile subscriber服务能力：service capability利用率：utilization带宽：bandwidth单边带：single-sideband扩频：spread spectrum大规模集成电路：large scale integrated circuits蜂窝点：cellular site蜂窝交换机：cellular switch无线机架：radio cabinet呼叫处理：call processing频谱利用率：frequency spectrum utilization有限的指定频带：the limited assigend ferquency band 服务区：servise area复杂的特性和功能：complicated features and functions大规模集成电路技术：large-scale integraesd circuit technology试验性的蜂窝系统：developmental cellular system中央协调单元：central coordinating element蜂窝管理：cellular administration传统移动电话的运行限制：operational limitiation of conventional mobile telephone system 有限的服务能力：limitied service capability无线通信行业：radio communcation industry可用的无线电频谱：available radio frequency spectrum所分配的频带：the allocated frequency band移动收发信机：mobile transceiver技术上的可行性：techological feasibility严格的频谱限制：severe spectrum limitations调频广播业务：FM broadcasting services传播路径衰耗：propagration path loss多径衰耗：multipath fading电话公司地方局:telephone company zone offices10.全球移动通信系统个人通信 personal communcation通信标准 communcation standrads固定电话业务 fixed telephone services网络容量 network capability移动交换中心 mobile switching center国际漫游 international roaming宽带业务 broadband services接口转换 interface conversion频谱分配 frequency allocation模拟方式 analogue mode蜂窝通信原理 cellular communcation principe拥塞 jamming蜂窝裂变 cellular splitting基站 base station寄存器 register收费功能 billing function接入方法 access method突发脉冲传输方式 brusty transimission mode开销信息 overhead information切换算法 handover algorithms短消息服务 short message services技术规范 technical specificationtotal access communcation system 全接入的通信系统global mobile communcation system 全球移动通信系统time division multiple access 时分多址facsimile and short message services 传真和短消息服务fixed communcation networks 固定通信网络a more personalized system 更加个性化的系统the cost and quality of the link 链路的价格和质量market growth 市场的发展fixed telephone service 固定电话服务coxial cable 同轴电缆interface convision 接口转换cellular communcation priciple 蜂窝通信原则frequency reuse and cell splitting 频率复用和蜂窝裂变cochannel interference 共信道干扰theoretical spectual capability 理论上的频谱容量micro-cellular system 微蜂窝系统base station transceiver 基站收发信机subscriber register 用户寄存器burst transmission mode 突发脉冲传输模式overhead information 开销信息advanced handover algorithms 先进的切换算法facsimile and short message services 传真和短消息服务the GSM technique specications GSM技术规范说明11.电路交换和分组交换电路交换 circuit switching分组交换 packet switching报文交换 message switching子网 subnet信头 header目的地址 destination address误差控制 error control存储转发方式 store-and-forward manner突发性 bursty传输时延 transimission delay中间交换设备 intermediate switching equipment交换技术 switching technique返回信号 return signal报文处理机 message processor给定最大长度 given maximum length信息转移 information transfer随机性 random专用电路 dedicated circuit电路利用率 channel ultilizationthe capability of soring or manipulating user's data 存储和处理用户数据的能力the special signaling message 特定的信令信息a well defined block df data callde amessage 被精心定义的称为报文的数据块the information regarding the source and destination address 涉及源和目的地址的信息the computer referred to a message processor 叫做报文处理器的计算机the store-and-forward transmission technique 存储转发传输技术the dynamic allocation of bandwith 带宽的动态分配the overall transmission delay of message 报文整个的传输时延switching technique 交换技术ciruit switching 电路交换message switching 报文交换packet switching 分组交换total path of connected lines 连线的整个通路source-destination pair 源到目的地的一对communication parties 通信各方transmission unit 传输单元intial connection cost incurred in setting up the circuit 在建立电路时的起初连接成本low delay constraint required by the user 用户所需的最短时延的限制the fixed dedicateded end-to-end circuit 固定专用的端到端电路low channel ultization 低的电路利用率12.ATM异步转移模式异步转移模式 asynchronous逻辑信道 logical channel虚电路 virtual circuits虚路径 virtual paths建议 recommendation网络层network level业务与应用层 service and application虚连接 virtual connection信息高速公路 information superhigh way点播电视 video-on-demand统计复用 statistical multiplexing数字化的信息 digital information标识符 identifer协议 protocols网络节点 network node宽带网 broadband networkATM论坛 ATM forum面向未来 future-proofed图象编码 image encodeing虚拟专用网 virtual private network数据处理 data processing被叫做信元的短的分组 short packets called cells每秒几百兆比特的速率 bit rates of several hundred megabits a second独特的复用方法 unique multiplexing method任何两个终端之间的物理连接 the physical connection between any two terminals交互式的视频业务 interactive video services多媒体业务的自然载体 a nature vehicle for multimedia services运营者和用户当前和未来的要求 the current and future requirement of both perators and users 高比特率信道的交换技术 the technique for switching high bit rate channel异步转换模式 asychornous transfer mode复用和交换技术 multiplexing and switching technique所承载的传输类型 the underlying type of transmission双重标识 dual identification虚电路 virtual circuit虚路径 virtual path信元在网络节点上的转移 the transfer of cells to the network nodes每秒几百爪比特 hundreds megabits a secondI.121建议 recommendation I.121服务质量 the quality of service与实际需求成比例 in proportion to the exact requirement网络所传送的应用和业务 the applications and service transported over a network构成虚网络的能力 the ability to construct virtual networks低价高效的利用网络设施 cost-effective use of infrastructure面向未来的 future-proofed协调传送不同业务的不同网络 coordinating different networks carrying different services未来的信息高速公路的基本部件 essential components of future information superhighways统计复用 statistical multiplexing资源的最佳使用 optimum use of resources虚拟专用网 virtual private networks13.多媒体多媒体 multimedia交互环境 interactive enviornment视频压缩 video compressin高清晰度电视 high definition television数字信号处理器 digital signal processor点播业务 on-demand services视频服务器 video servers硬件、软件和应用 hardware,software and applications存储 storage彩显 colour moniter全活动图象 full motion picture视频编码器 vision encoder字节 bytemixture of hardware,software and applications 硬件、软件和应用层interactive environment 交互环境personal desk top computers 个人桌面电脑video compression 视频压缩the vision encoder 视频编码器video-on-demand interactive services 交互式视频点播业务multimedia enviroment 多媒体环境visual images 视频图象hard disk storage 硬盘存储colour monitor 彩显the standards of multimedia 多媒体标准motion pictures 活动图象consumer quality of video and audio 顾客质量的视频和音频broadcast images 广播图象high definition television 高清晰度电视coding algorithms 编码算法digital signals processor 数字信号处理器14.公用电信网公用电信网 public telecommunication network本地环路 local loop交换节点 switching node双绞线 twisted pair外部呼叫 external call端局 end office数字数据系统 digital data systems二线连接 two wire connection收费中心 toll center电路交换网 circuit-switching network电话用户 telephone subscriber数据流量 data traffic链路 link中继线 trunk半双工的 half-duplex全双工的 full-duplex中间交换节点 intermediate switching node音频电路 voice-frequency circuit汇接交换机 tandem switch拓扑 topology接点间的 internode路由 route全双工的连接 full-duplex connection集中话务量的功能 the funcion of concentrating traffic被称为汇接交换机的交换节点 the switching node called tandem switch一小部分用户 a fraction of subscribers在站和网络之间的接口 the interface between the station and the network 发送数字信号的用户 the subscriber that transmit digital signal国家网络 national network结构部件 architectural components接点间的支路 the branches between nodes树状拓扑 tree topology传输设备 transmission facilities多条音频电路 multiple voice-frequency circuits同步时分复用 synchronous TDM相邻的端局 adjacent end offices全连通性 full connectivity被分离开的子网 isolated subnetworks高效中继线 high-usage trunks路由选择的基本次序 basic order of selection主干体系网络 backbone hierarchical network连到不同端局的俩个用户 two subscribers attached todifferent office交换区 exchange area15.综合业务数字网全球通信 global communications灵活性 flexibility端到端的数字连接 end-to-end digital connectivity开放网络 open network语声编码 voice encoding综合业务数字网 integrated services digital network系统结构 infrastructure国际标准化组织International Organization for Standardization通信载体 communication carriers传输媒体 transmission medium接口设备 interface equipment带宽限制 bandwidth limitation交换设备 switching equipment语音编码 voice encoding脉码调制 pulse code modulation基本接入 basic access综合业务数字网 the integrated services digital network国际标准化组织 the International Organization for Standardization由于传输媒体导致的质量下降 degradation due to the transmission medium4kHz话路中所固有的带宽限制 bandwidth limitations inherent in a 4kHz voice channel标准化的接口 standardized ports脉（冲编）码调制 pulse code modulation数字通信 digital communicationISDN的标准和系统结构 ISDN standards and system architecture全球通信 global communication数字技术的逐步应用 progressive application of digital technology共同通信载体 public communication carriers高质量 enhanced quality大量的接口设备 substantial quantity of interface equipment在传送话音、数据、视频和其他业务上的灵活性 flexibility in the transmission of voice , data , video and other services带宽的限制 bandwidth limitations端到端的数字连接 end-to-end digital connectivity语音编码技术 voice encoding techniques基本接入信令速率 basic access signaling rate统一的接入 universal access试验性的技术 experimental technology16.电信世界的业务和未来X.25协议 X.25 protocol电视信号 television signals宽带业务 narrowband services基本接入 basic access电信业务 teleservice用户电报 telex无线电波 radio waves地面天线 ground antenna同轴的 coaxial直接广播系统 direct broadcast system端到端的时延 end-to-end delay抖动 jitter繁忙小时 peak hours芯片技术 chip technology高清晰度电视 high definition television运行也维护 operations and maintenance现有的公用网络 the existing public network传统的双向对话 classical two-way voice conversation基于X.25协议的分组交换数据网络 packet switched data network based onX.25 porotocols对网络的拥护接入 the user access to the network对网络的用户接入 the user access to the network信道速率为70 Mbit/s的电路交换业务 a circuit switched service with a channel rate of 70 Mbit/S 与业务无关的网络 the service-independent network对资源的最佳统计共享 the optimal statistical sharing of the resources电信业务 telecommunication service用户电报网 telex network文字报 messages of characters双向对话 two-way voice conversation同轴树状网络 coaxial tree network公用天线的电视网络 community antenna TV network直接广播系统 16 direct broadcast system以太网 Ethernet令牌总线网和令牌环网 token bus and token ring network全球范围的独立网络 world-wide independent networks电话网络的繁忙小时 the peak hours in the telephone network资源共享 resource pooling繁忙小时流量 23 peak hour traffic窄带业务的综合 integration of narrow-band services在语声编码和芯片技术方面的进步 the progress in speech coding and chip technology新的电信业务 a new teleservice对新业务要求的适配 adapting to new service requirements移动电话：the mobile telephone第三代移动业务：the third generation mobile service无线通信：the wireless communication手机：the handset 全球漫游：the global roaming 无线标准：the wireless standard 蜂窝点：the cell sate 峰值数据速率：the peak data rate平均吞吐量：the average throughput 下载：the download多址接入：the multiple access扩频：the spread spectrum technology时隙：the timeslot To comebine high speed mobile access with internet protocol-based service将高速移动接入与基本IP的服务结合起来To standardized future digital wireless communication对未来的数字无线通信标准化theinternet protocol –based services基于互联协议的服务the single global wireless standard但与全球无线标准to accommodation the continuing growth of voice services as well as new wireless internet services容纳语音服务的持续增长及新的无线因特网服务 the spectrum allocation flexibility频谱分配的灵活性 the international telecommunication union国际电信联盟the boundaries between communication ，information，media and entertainment在通信，信息，媒体，娱乐之间的分界线。
电子信息类专业英语(西电第二版)Unit 15 Data Communications
电子信息类专业英语（西电第二版） Unit 15 Data Communications
Unit 15 Data Communications Passage A Data Communications
The rapid growth of data communications has been influenced primarily by the increasing need to move information to and from computers. Modern time-shared computers can communicate with many data stations simultaneously. Other forms of data transmission which the telephone and telegraph lines are called upon to handle are batch data transmission, real-time transmission (as in the case of airline reservation systems), banking and credit data, man-computer conversation with the aid of graphics, data collection systems and automatic meter reading. The combination of computers and data communication places such new requirements on the systems, which must handle them, that one can refer to them better as teleprocessing rather than telecommunications.[1]
TM127
Form: RWPRR401-B C C S通 函Circular 中国船级社（2011年）通函第63号总第127号2011年7月18日（共2+9页）发： 本社总部有关处室，本社验船师、审图中心，有关船东，船舶管理公司，船厂，设计单位关于执行IACS统一要求UR E22第1次修订版的通知国际船级社协会（IACS）于2010年9月批准了统一要求UR E22－On Board Use and Application of Programmable Electronic Systems的第1次修订版。
本次修订版新增一系列要求，旨在对船舶设备中使用无线通信技术形成统一评估方法。
UR E22第1次修订版的主要内容如下：1、新增2.1.2，因为III类系统的失效可能导致严重的灾难，所以提出在此类系统中采用非传统技术时应采用工程分析的方法（参见SOLAS公约第II-1章第55条），并且提交足够的证据使船级社满意。
2、新增2.3.6和2.3.7，补充了数据通信链的以下要求：（1）一旦数据通信失效，系统自检功能应能将系统置于最小危险状态；（2）数据通信链应具有足够的容量，在足够的时间内传送所有必需的信息以及避免出现阻塞状况。
3、新增2.4节，III类系统采用无线数据通信链应符合2.1.2的规定，II类系统采用无线数据链时除应满足2.3的要求外，还应满足以下要求：（1）重要设备连续运行所要求的功能，若依赖于无线数据通信链，应具有在系统可接受的时间段内能投入使用的替代控制措施。
（2）无线数据通信应使用国际认可的无线通信系统协议以及满足以下要求：①信息完整性：故障预防、检查、诊断和修正，以便收到的信息（与发送的信息相比较）不被破坏或更改；②配置和设备验证：应仅允许与系统设计中包含的设备连接；③信息加密：机密和/或关键数据内容的保护；④安保管理：网络资产的保护,防止非法的存取网络资产。
（3）无线系统应满足国际电信联盟和船旗国主管机关对无线频率和功率水平的要求。
罗伯特茱莉亚特 USIT T DMX 512 用户手册说明书
USER'S MANUALUS I T T D M X 512 ACCO R D E D W I R I N G D A T AVERSION 1 - 2EDITION : 02/01/07Robert Juliat S.A.S. 32, rue de Beaumont, F 60530 Fresnoy-en-Thelle - phone : +33 (0)3 44 26 51 89 - fax : +33 (0)3 44 26 90 7**********************DN40729601CONTENTS1. OVERVIEW ..........................................................................................................................page 42. GETTING STARTED ............................................................................................................page 53. USER’S INTERFACE ............................................................................................................page 53.1. ROOT AND GENERAL MENU ..............................................................................page 53.2. OPTIONS MENU ..................................................................................................page 63.2.1 Channel option .....................................................................................page 63.2.2 Curves option ........................................................................................page 73.2.3 Local option ..........................................................................................page 73.2.4 Limit option ..........................................................................................page 83.2.5 Stage option .........................................................................................page 83.2.6 Test option.............................................................................................page 83.2.7 Preferences option ...............................................................................page 93.2.7.1 Soft start .................................................................................page 93.2.7.2 Patch ........................................................................................page 93.2.7.3 Booster ....................................................................................page 93.2.7.4 Smoothing ..............................................................................page 103.2.7.5 Number of steps ....................................................................page 103.2.7.6 Analog input level .................................................................page 103.2.8 Information option ...............................................................................page 103.2.8.1 Protocol ..............................................................................................page 103.2.8.2 Errors .......................................................................................page 113.2.8.3 Frequency ...............................................................................page 113.3 RESET MENU ........................................................................................................page 113.3.1 Full parameter reset .............................................................................page 113.3.2 Parameter reset by groups ..................................................................page 113.3.3 Hardware reset .....................................................................................page 123.4 CHANNEL NUMBER DISPLAY ..............................................................................page 12APPENDIX - Network256 steps chart (DMX or AVAB) & Wiring data ..................pages 13-171. OVERVIEWDIGI 6 is a 6-channel dimmer, entirely digital. It can recognize a digital order in DMX 512 or AVAB protocols. Each time the unit is switched on, and each time an in-series connection is made, the protocol is tested and recognised.DIGI 6 accepts analog 0/+10V and local controls. The output level is determined by the highest input level (H ighest level takes over), and according to the curves which have been assigned to the channels.DIGI 6 is designed for either one-phase or three-phase A.C. Voltage. The unit will need a frequency maintained between 45.5 to 64 H z. It is strongly recommended that the networksupply maintains constant this frequency. Read with care relevant technical sheets for additional information concerning electrical connections and dimmer output.DIGI 6 can also :- receive various parameters (fi rst channel, curves)- receive local input levels - display input levels- display information which facilitates optional functioning.All these functions are performed by the DIGI 6 in addition to real time light control. The user interacts with the unit through use of the keyboard and display.The keyboard consists of 4 function keys and a RESET key. A LED display off ers 5 elements of seven segments. The keyboard and display are conveniently located on the front board. On this mini instrument panel are found 2 LEDS - one green "DATA ON ” LED, and one red "ERROR " LED.2. GETTING STARTEDEach orders are stopped for a few seconds when the unit is switched on, or after each push on the RESET key. Then, local and analog (if any) orders are recognized and executed.After recognition of protocol, digital orders are executed.Meanwhile, two messages quickly follow each other on the display:- The message "Lx-xx " ; "x-xx " represents the program version in EPROM .- The "rJxxx " message, remains on display. "xxx " represents the number assigned to the fi rst channel.The following reference manual will help you access the many optional features of DIGI 6. To obtain maximum performance, we advise you to read the following pagraphs while operating DIGI 6.3. USER’S INTERFACE3.1. ROOT AND GENERAL MENUAs indicated, when switched on, DIGI 6 displays a "rJxxx " message. We shall refer to it as the "ROOT ", since it starts the dialog between you and the dimmer.When you press the SELECT key for one or more seconds, the display changes. You receive the fi rst item or option in a list of choices. Let us call this list "MENU ".There are 8 optional items in the menu program:- Circ : allows the user to assign the fi rst channel number.- Courb : allows the user to assign a curve to each of the six channels.- LOCAL : allows the user to assign local control levels to the channels.- Limit : allows to set a limit on each channel- StAGE : displays external input levels - digital or analog as well as local levels.- tESt : allows assignment in local mode of preprogrammed levels.- PrEF : allows the user to confi gure several hard/ soft parameters.- InFO : displays information concerning protocol and frequency.Note: The seven segments of the displays allow only a limited range of written characters. Thus, the above messages must be a mixture of lower and upper case letters.As soon as the fi rst menu option is displayed, you can access sequentially and cyclically all other options, simply by pressing + and - keys.Pressing the EXIT key will allow reaccess to the "root" display (rJxxx). Pressing SELECT then allows access to the displayed function.When one function of the menu is selected, the keys have the following signifi cance:- + and - keys allow you to change the displayed level upwards or downwards.- Pressing EXIT for one second allows you to return to the same item in the menu.- The SELECT key allows the user, for certain functions, to modify the selected item;for example - to choose a channel between 1 and 6.- Combining EXIT and - allows you to reset the parameters.- Combining EXIT and + allows you to display the channel number.(Please refer to the following text for further detail.)Note: For comfort of utilization, some fonctions are delayed: initial entry into the menu, exit from any function with the EXIT key, and the parameter reset.3.2 OPTIONS MENU3.2.1 CHANNEL OPTIONThe menu "Circ" represents the option channel, which allows the user to select the digital assignment of the fi rst channel. Once selected, the dimming unit recognizes which information coming from a lightboard will be considered for the fi rst channel, as well as the following ones. For example, if the number chosen for the fi rst channel is 126, the six channels in the dimming unit will be assigned the following numbers in sequence : 126, 127, 128, 129, 130, 131.To change the number of the fi rst channel, the syntax is as follows:When "Circ" displays (the fi rst item in the menu), press the SELECT key. The display shows d1 (for the fi rst channel), followed by the channel number selected for the fi rstchannel (1, 2 or 3 digits). Keys + or - allow modifi cation, up or down, of the number of the fi rst channel. The modifi cation proceeds step by step, by successively pressing the keys + or -, or by continuous pressure of either. In using continuous pressure, the digit changes slowly to begin with, then increases in rapidity. You can also combine the two techniques to obtain the desired number quickly. The values follow each other in a cyclical manner ; #1 preceded by the largest channel number assignable - 512 in DMX, 256 in AVAB - which in turn is followed by #1. With the patch on, each channel can be set independently.Once the number of the fi rst channel is chosen, you may press EXIT to go back to the Menu. Note: The channel numbers above DATA size (>256 AVAB, >512 DMX) will not be decoded by the unit.3.2.2 CURVES OPTIONThis option, symbolized by "Courb " (Curves) in the menu, makes possible the assignment of an incoming/outcoming curve to each channel. To do this, the following syntax is used :Press the SELECT key. The display will show "C1" (for the fi rst channel), followed by one of the following symbols:- linL : Linear Light curve.- lint : Linear Voltage curve.- FLU : Fluorescence curve.- rEL : Static Relay.Pressing + and - will cyclically display the fi ve curves. When the desired curve is selected, press SELECT to access the next channel. After the last channel (C6), C1 reappears. It is always possible to return to the menu by pressing EXIT (for one or more seconds).In assigning a curve, keys + and - must be pressed step by step.Once a channel is assigned a curve which is not the default Linear Light curve, the small red dot on the second of fi ve displays begins to blink. Otherwise, if all the curves are the Linear Light type, the blinking dot is extinguished. This function is called CURVES ACTIVE .It is always visible on the menu.3.2.3 LOCAL OPTIONThis option, symbolized by "LOCAL " on the menu, makes assignment of local level orders between 0% and 100% to each channel possible. Press SELECT to access this function. The display changes to "L1" (for the fi rst channel) followed by "=" and the local channel level, which will be "0" for 0%, "xx " for an intermediate level and "FF " for 100%.The local level of the channel selected can be modifi ed by using the + and - keys. At 100% (FF ), the + key will not modify the local level ; similarly, at 0% the - key is no longer active.Either key can be pressed step by step, or continuously.The level orders which are incoming from the lightboard are between 0 and 255. The same display (10% for example) can correspond to diff erent levels (here, 26, 27 or 28).Thus, individual pressing of the + and - keys, while always inducing a modifi cation of the level order, does not necessarily modify the level displayed.The "=" sign is blinking while the local channel level is below external levels of the same channel. As soon as the local level equals the highest external level (digital or analog), the "=" sign stays lit continuously.Once the desired level is set, press SELECT to access the next channel adjustment. After the last channel (C6) is set, C1 appears again. You may always return to the menu by pressing EXIT. Once a local level is greater than 0, the small red light over the last of the fi ve displays will begin blinking. If, however, all local levels equal 0, this red light extinguishes. This display function is called "ACTIVE LOCAL". It is visible on the root, in the menu, and during all other options.3.2.4 LIMIT OPTIONThe option “Limit” allows the setting of a maximum output value for each channel. A channel at 100% is not modifi ed, a channel limited at 0% will have no output value, whatever the order sent to it.For intermediary values, the limit level chosen will apply to the order received. For instance, a channel limited at 80% dimmed down at 50% will have an output value of 40% (50/100 x 80/100).Press SELECT and the display shows "li 1 FF" which means that channel 1 is at 100%(FF for full).The "+" and "-" keys enable to change the limit value from 100% to 0%. "SELECT" gives access to the channels C1 to C6 (after C6, back to C1) and also to the set up.You may always return to the menu by pressing EXIT. If at least 1 limit value is diff erent from FF (Full), the small red dot over the fourth display starts blinking. This feature is called ACTIVE LIMITATION and can be found in the various menus.3.2.5 STAGE OPTIONThe option symbolized by "Stage" allows viewing of order levels for each channel.Press SELECT, and the display shows "P1" for the fi rst channel, followed by two digits which represent the highest external order (digital or analog). After a brief moment, the display changes automatically and indicates the local order level. To diff erentiate between the external and local order levels, the external order (coming from a lightboard) appears as a "P" and the local order as an "L" with the "=" sign. As long as no keys are pressed, the display fl ashes alternately between external (P) and local level (L).SELECT allows access to channels C1 to C6. After C6, C1 returns, and the search for levels proceeds again. EXIT allows return to the menu at any time.3.2.6 TEST OPTIONThe option, represented by "tESt" on the menu, allows assignment of local levels which are preset at 50% for each channel. During the test, this level replaces the existing local level. The light output will of course follow the curve of the channel being tested.The SELECT key allows access to the test function. The display indicates "t1" for thefi rst channel, "=" for local levels, and "50" for the percent. The 50% local test level actually becomes the commanding level if it is higher than external levels for the same channel.CABLAGE ANALOG 0/+10V.0/+10. ANALOG WIRING1 à / to 6 : Ch8 + 9 : 0V.7 : Non utilisé /Not usedCABLAGE DATA XLR 5 /XLR 5 DATA WIRINGPIN12345DMX 5120vData -Data +--AVAB0vData -Data +--APPENDIXWhen SELECT is pressed a second time, the second channel is tested, and the fi rst channel returns to its original level. As with all other options, the display returns to channel 1 after channel 6. At any time, pressing EXIT allows you to return to the menu, and all local levels return to their previously set levels.3.2.7 PREFERENCES OPTIONThis option allows you to confi gure several hard/soft parameters. Once a parameter changes from its default value, the 5th LCD dot begins to blink.3.2.7.1. Soft startThis option will prevent potential problems created by peaks of current (generated when a whole rig is turned on for instance).3.2.7.2. PatchWith this function, each channel number can be set independently.3.2.7.3 BoosterThe BOOSTER function provides a very reliable wiring; each mobile unit is provided with a circuit for reamplifying the digital signal, in order to preserve the signal quality. The function is implemented in hardware for the mobile units (it is not necessary for units in cabinets).Press "+" or "-" to disable (and re-enable) the booster. The default value is Booster OFF .Note: When the units are turned off , the BOOSTER function is automatically by-passed.Preferencs Soft start :Patch :Booster :Smoothing :Display :Analog :Display St P b F n An Default On Off Off OnDecimal 0/10v3.3.3 Hardware ResetThe hardware reset is obtained by pressing the RESET key. It governs the immediate restart function of the DIGI 6 without changing the parameters and channels’ levels in the unit.3.4 CHANNEL NUMBER DISPLAYThe six channels are always indicated in every option by the numbers 1 to 6. If you want to remember which number is assigned to which channel, press the SELECT and "+" keyssimultaneously. While pressing the two keys, you will see the Channel Data Number . After release of the keys, the display returns to its previous condition.The Channel Number Display function is active in the Curves (Courb), Limit, Local , Test and Stage options.3.2.7.4 SmoothingThis function was added to perform a better light control by increasing the digital input command resolution from 256 steps to 7500 steps.3.2.7.5 Number of stepsThis function allows you to choose the input level display base: DEC imal (100 steps) or HE xa D ecimal (256 steps). Which is very useful for checking the digital transmission during service operations.Press "+" and "-" to make your choice. The default value is decimal. If you choose hexadecimal, the 4th LCD dot will blink. The annexe table gives, for the 256 steps of a digital DMX or AVAB order, the decimal and hexadecimal display values.3.2.7.6 Analog input levelThis function allows you to choose the input analog level 0/+10V or 0/+5V for a 0% to 100% order.Press "+" and "-" to make your choice. The default value is decimal. If you choose hexadecimal, the 4th LCD dot will blink.3.2.8 INFORMATION OPTIONThe option "InFO " allows you to know the parameters which are recognized by the DIGI 6.3.2.8.1 ProtocolPress SELECT to see on the fi rst display either the letter "D " or "A ", or the sign "-" followed by "Pro ", which indicates which protocol has been recognized ; "D " for DMX512 protocol, and "A " for AVAB protocol. The hyphen "-" indicates that no protocol has been recognized, or that the series line is missing or of bad quality.Information about the presence and quality of the series link is also given by two redand green LEDs in the middle of the display. They illuminate or extinguish according to the series status, regardless of which selection has been chosen in the menu.The green DATA LED blinks if a signal is detected on the data line (even parasites). The red DATA LED remains extinguished if the signal respects a known protocol, or if no signal is received. The red LED alights if the signal does not respect the DMX512 or AVAB protocols.3.2.8.2 ErrorsThis function specifi es the erroneous packet rate for 1000 input packets. The display shows "ER 000" for a proper line series.Press EXIT to return to the menu, or press SELECT to have access to the frequency function.3.2.8.3 FrequencyWhile pushing SELECT when series errors are displayed, you have access to the thirdinformation option - the frequency option. The frequency is given in the form xxHx . Here,"H " symbolizes the Hertz frequency unit. The dimmer is not designed to act as a frequency meter. Thus, the level displayed is merely an indication of power stability. As always, EXIT allows you to leave the option ; SELECT allows reaccess to the protocol function.3.3 RESETYou have several reset possibilities, software or hardware. The software resets concern the DIGI 6 parameters; the fi rst channel number, the restitution curves, the local orders and the preferences.The default levels are 1 for the fi rst channel, Linear Light for the curves, 0% for the local levels, booster (for preferences, see tab in the "Preferences" section). Of course, you are free to modify any or all of the parameters. The new levels will be saved (on a static RAM ) - even when the DIGI 6 is not operating.To put parameters back to their default levels, use the following software reset functions.3.3.1 Full parameter resetThe reset of all parameters (PARAMETER RESET ) recharges the default values. To do this, you must return to the root (rJxxx ) by pressing the EXIT key once or twice (wait a moment - this key is delayed). Then, press the EXIT and "-" keys simultaneously, for at least one second. During your reset, the message "rESEt " appears on the display, indicating that reset is occuring.After reset, the display returns to "rJ1", and the red light dots remain unlit.3.3.2 Parameter reset by groups.The reset of selected parameters is accomplished by choosing an option, and then pressing the EXIT and "-" keys simultaneously. In the Circ option, you return to the number of the fi rst channel, Number 1. In the curves option (Courb ), however, all channels return to linear light curve. The reset of local orders can be accomplished in Local , Test , or Stage options. The preferences reset is accomplished in Preferences or Information options.The local reset is also delayed by about one second. During the reset, the "rESEt " message appears on the display, indicating that it is being executed.。
数据采集外文翻译(00002)
数据采集外文翻译附录附录A外文资料Data CollectionAt present,the management of China’s colleges and universities’apart ments are developing toward standardization and market development,accid ents have occurred in electricity,while some colleges and universities have i nstalled apartment energy metering control system,however,these systems m onitor the prevalence of low level,billing accuracy is low,electricity-sharing,t he network number of the drawbacks of low extent.Therefore，improving t he Energy Measurement monitoring device has become more urgent．The i ssue of student hostels in colleges and universities to monitor energy meter ing system to study，design the student hostels in colleges and universities of the electricity data collector apartment.Data acquisition, also known as data acquisition, is the use of a devic e that collect data from outside the system and enter into an interface wit hin the system.Data acquisition technology is widely cited in the various fie lds.Such as camera, microphone, all data collection tools.Data is being colle cted has been converted to electrical signals of various physical quantities such as temperature, water level, wind speed, pressure, etc., can be analog, it can be digital.Sample collection generally means that a certain time int erval (called the sampling period) to repeat the same point of data collecti on.The data collected are mostly instantaneous value, but also a feature wi thin a certain period of time value.Accurate data measurement is the basis for data collection.Data measurement method of contact and non-contact detection elements varied.Regardless of which method and components are measured object does not affect the status and measurement environment a s a precondition to ensure the accuracy of the data.Very broad meaning of data collection, including continuous physical hold the collection across th e state.In computer-aided mapping, surveying and mapping, design, digital graphics or image data acquisition process may also be called, this time tobe collected is the geometric volume (or include physical quantities, such as gray)data.[1] In today's fast-growing Internet industry, data collection h as been widely used in the field of Internet and distributed data acquisitio n field has undergone important changes.First, the distributed control appli cations in intelligent data acquisition system at home and abroad have ma de great progress.Second, the bus-compatible data acquisition plug-in numb er is increasing, and personal computer-compatible data acquisition system the number is increasing.Various domestic and international data collection machine has come out, the data acquisition into a new era.Digital signal processor (DSP) to the high-speed data processing ability and strong peripherals interface, more and more widely used in power qu ality analysis field, in order to improve the real-time and reliability.The D SP and microcomputer as the center of the system, realize the power syste m signal collection and analysis. This paper based on the FFT algorithm with window interpolation electric system harmonic analysis, improves the accuracy of the power quality parameters. In electricity parameter acquisiti on circuit, by highaccuracy transformer and improve software synchronous communication sampling method to conduct electricity parameters of the acquisition.The system consists of two main components, mainly complete data ac quisition and logic control.To synchronous sampling and A/D converter circ uit priority . The DSP development board(SY-5402EVM),complete data pr ocessing. THE signal after transformer, op-amp into A/D converter, using DSP multi-channel buffer (McBSP) and serial port (A/D connected, data co llection and operations. At the same time, adopt PLL circuit implementatio n synchronous sampling, can prevent well due to sampling synchronization and cause the measuring error. The overall system diagram of the A/D c onverter chooses the Analog to produce stats redetect (AD) company AD73 360. The chip has six analogue input channel, each channel can output 16 the digital quantity. Six channel simultaneous sampling, and conversion, ti meshare transmission, effectively reduce generated due to the sampling tim e different phase error. SY - 5402EVM on-board DSP chip is TI company' s 16 fixed-point digital signal processor TMS320VC5402. It has high costpe rformance and provide high-speed, bidirectional, multi-channel belt cushion,be used to serial port with system of other serial devices directly interfac e.The realization method of ac sample：In the field of power quality an alysis,The fast Fourier transform (FFT) algorithm analysis of electric syste m harmonic is commonly used.and the FFT algorithm to signal a strict re quirements synchronous sampling. The synchronous sampling influence: it's difficult to accomplish synchronous sampling and integer a period truncati on in the actual measurement, so there was a affect the measurement accu racy of the frequency spectrum leakage problem. The signal has to deal w ith through sampling and A/D conversion get limited long digital sequence, the original signal multiplied by A rectangular window to truncated. Time-domain truncation will cause the detuning frequency domain, spectrum lea kage occurs. In the synchronous sampling, because the actual signal every harmonic component can't exactly landed in frequency resolution point in, but fall between the frequency resolution points. But FFT spectrum is disc rete, only in all sampling points, while in other places of spectrum is not. Such through FFT and cannot directly get every harmonic component, but only the accurate value in neighboring frequency resolution point value to approximate instead of, can cause the fence effect error.The realization m ethod of synchronous sampling signal：According to provide different ways of sampling signal, synchronous sampling method and divided into software synchronous sampling method and hardware synchronous sampling metho d is two kinds. Software is synchronous sampling method by micro control ler (MCU) or DSP provide synchronized sampling pulse, first measured the measured signal, the sampling interval period T Δ T = T/N (N for week of sampling points), Thus the count value determined timer,Use timing inte rrupt way realization synchronous sampling. The advantage of this method is no hardware synchronous circuit, simple structure .This topic will be t he eventual realization of access to embedded systems，the realization of th e power measurement and monitoring,monitoring system to meet the electri city network,intelligence requirement,it promote the development of remote monitoring services,bringing a certain degree of socio.economic effectivenes s.On the fundamental reactive current and harmonic current detection, there are mainly 2 ways: First, the instantaneous reactive power theory bas ed method, the second is based on adaptive cancellation techniques.In addi tion, there are other non-mainstream approach, such as fast Fourier transf orm method, wavelet transform.Instantaneous power theory based on the method of offensive principle s are: a three-phase current detection and load phase voltage A, the coord inate transformation, two-phase stationary coordinate system the current va lue, calculate the instantaneous active and instantaneous reactive power ip iq,then after coordinate transformation, three-phase fundamental active cur rent, with the final load current minus the fundamental current, active po wer and harmonic currents are fundamental iah, ibhi, ich.From:Principles of Data Acquisitio数据采集目前，我国高校公寓管理正在向着正规化、市场化发展，在不断提高学生方便用电的同时，用电事故频有发生，虽然部分高校公寓已经安装了电能计量监控系统，但这些系统普遍存在着监控程度低、计费精度不高、电费均分、网络程度低等诸多端。
信息网络通信基础
1.13
1.2.3 物理结构 Physical Structures 连接类型 Figure 1.3 Types of connections: point-to-point and multipoint点到点
和多点
Reserved capacity VS Shared capacity
Solution
Number of links = n(n-1)/2=8(8-1)/2=28 Number of ports per device = n-1 = 8-1=7
Data Communications & Networking
1.17
Figure 1.6 A star topology connecting four stations
1.2
Data Communications & Networking
1.3
Data Communications & Networking
1.4
Chapter 1
Introduction
绪论
Data Communications & Networking
1.5
1-1 DATA COMMUNICATIONS 数据通信
Topics discussed in this section:
Components 组成 Data Representation 数据表示 Data Flow 数据流
Data Communications & Networking
1.6
Data communications are the exchange of data between two devices via some form of transmission medium such as a wire cable. The effectiveness of a data communications system depends on four fundamental characteristics: 1. Delivery. 传递性 The system must deliver data to the correct destination 2. Accuracy. 准确性 3. Timeliness. 及时性 4. Jitter. 抖动性 Jitter refers to the variation in the packet arrival time. (audio or video)
信息通信网络 知识点
9.unipolar(单极性编码);polar(极化编码);bipolar
10.B8ZS +000+—0—+ —000—+0+—
11.HDB3 奇+000+ —000— 偶+—00— —+00+
17.Data link layer node to node delivery**addressing**access control**floe control**error handling**synchronization
18.What is 4B/5B? 4B/5B ensures that there cannot be a data sequence of more than three 0s transmitted across media in FDDI protocol. This takes care of the bit synchronization problems arising from long strings of 0s in NRZ-I encording.
15.CSMA/CD: carrier sense multiple access with collision detection . is an access method of ehternet. (project 802.3)
16.10Base－T 10Mbps Baseband with twisted pair UTP, 100 meters length per segment
带有网络攻击的Markov跳变系统混杂触发控制器设计
带有网络攻击的Markov跳变系统混杂触发控制器设计王春平1，谭天2，高金凤2（1.浙江理工大学科技与艺术学院，浙江绍兴 312369；2.浙江理工大学机械与自动控制学院，浙江杭州310018）摘 要：文章针对马尔科夫（Markov）跳变系统，基于优化数据通信、提升系统响应和性能的考虑，设计了混杂触发控制器和量化器。
利用伯努利分布将时间触发和事件触发相结合，以平衡系统的性能和数据通信，同时利用量化将连续信号转化为离散信号，提高采集数据的传输速率。
特别针对工业控制系统的网络安全问题，考虑系统即便在遭受来自外界的网络攻击时，文章设计的输出反馈控制器依然能够保持系统稳定。
在此基础上，借助于MATLAB的控制系统工具箱，对一个实际电路系统进行电压与电流控制的仿真，结果表明所设计控制器的有效性和实用性。
关键词：网络攻击；输出反馈；混杂触发机制；量化；Markov跳变系统中图分类号： TP391.9文献标识码：AHybrid-driven controller design for Markovian jumpsystem with network deception attackWa ng Chunping1, Ta n Ti an2, Gao Jinfeng2（1. Keyi College of Zhejiang Sci-Tech University, Zhejiang Shaoxing 312369; 2. Faculty of Mechanical Engineering andAutomation, Zhejiang Sci-Tech University, Zhejiang Hangzhou 310018）Abstract: A class of Markov jump systems are investigated. In this system, hybrid-driven controller and quantization are adopted to optimize data communication and improve system response and performance. Bernoulli distribution is used to combine time-triggered with event-triggered to balance system performance and data communication. Quantization is introduced to transform continuous signal into discrete signal for improving the transmission rate of collected data. Aiming at the network security of industrial control system, the relevant deception attack model is introduced in order to maintain the system’s stability even when it is attacked by the malicious attacker. The relevant output feedback controller is designed. And a simulation based on actual physical system is given, which shows the effectiveness and authenticity of the designed controller.Key words: deception attack; output feedback; hybrid-driven mechanism; quantization; Markov jump systems1 引言随着工业互联网的关注度不断提升，网络安全问题也随之得到广大学者的关注和研究。
A Hierarchical Graph-Clustering Approach to Find Groups of Objects
A Hierarchical Graph-Clustering Approach tofind Groups of ObjectsKarl-Heinrich AndersInstitute of Cartography and GeoinformaticsUniversity of HannoverAppelstraße9a,30167Hannover,Germanykarl-heinrich.anders@ikg.uni-hannover.deKEY WORDS:Map Generalization,Unsupervised Clustering,Neighbourhood Graphs1IntroductionNowadays,the necessity of automatic interpretation and analysis of spatial data is getting more and more important, because the amount of digital spatial data continuously increases.On the one hand,there are raster data sets,on the other hand vector data that are predominantly based on different landscape models.Differences between these landscape models are,e.g.,the object type,the degree of generalization,or the geometric accuracy of the captured landscape objects.The pure interactive processing and analysis of large spatial databases is very time-consuming and expensive.Especially the manual analysis of spatial data for the purpose of data revision will reach the limit of technical feasibility in the near future,because modern requirements on the up-to-dateness of data lead to ever shorter update cycles.The automatic interpretation of digital landscape models needs the integration of methods of thefield of spatial data mining or knowledge discovery in spatial databases into geographical information systems(GIS).In general, the automatic interpretation of a digital landscape model(DLM)can be divided into the interpretation based on a specific model of the DLM,the interpretation based on a generic model of the basic elements of the DLM,and the unsupervised interpretation of the DLM.Clustering methods can be divided into supervised and unsupervised methods.Unsupervised clustering or learning methods can be used for the third case of DLM interpretation. Especially unsupervised clustering methods are well suited for the model generalization and the cartographic generalization of DLM data if these methods can recognize clusters of arbitrary shape.There are a lot of different clustering approaches,but most of them need certain prerequisites,like the distribution function of the data,or thresholds for similarity tests and terminating conditions.In many cases,clustering methods can onlyfind clusters with a convex shape and without holes(e.g.,maximum-likelihood).In this paper a new unsupervised clustering approach called Hierarchical Parameter-free Graph CLustering (HPGCL)for the automatic interpretation of spatial data is described(Anders2003).The HPGCL algorithm canfind clusters of arbitrary shape and needs neither parameters like thresholds nor an assumption about the distribution of the data or number of clusters.The novelty of the HPGCL algorithm lies on the one hand in the application of the hierarchy of neighbourhood graphs(also called proximity graphs)to define the neighbourhood of a single object and object clusters in a natural and common way and on the other hand in the definition of a median based,threshold free decision criteria for the similarity of clusters.In the HPGCL algorithm the Nearest-Neighbour-Graph,the Minimum-Spanning-Tree,the Relative-Neighbourhood-Graph,the Gabriel-Graph,and the Delaunay-Triangulation are used.It will be shown that the hierarchical relationship of these proximity graphs can be used for a natural generalization process in the sense of a coarse-to-fine segmentation of a data set.One additional feature of the HPGCL algorithm is that in general a limiting number of clusters greater than one will be found.In contrast,general hierarchical cluster algorithms require the minimal number of clusters as a parameter, otherwise they will always group all objects of a data set in one big cluster.12RELATED WORK2 2Related WorkIn the context of data aggregation,there are many approaches in GIS and in digital cartography,namely in model or database generalization.(Richardson1996)and(van Smaalen1996)present approaches to come from one detailed scale to the next based on a set of rules.If such rules are known or models of the situation are available,good results can be achieved(cf.(Sester,Anders&Walter1998)).However,the main problem being the definition of the rules and the control strategy to infer new data from it(Ruas&Lagrange1995).Current concepts try to integrate learning techniques for the derivation of the necessary knowledge(Plazanet,Bigolin&Ruas1998), (Sester1999).Clustering is a well established technique for data interpretation.It usually requires prior information,e.g.about the statistical distribution of the data or the number of clusters to detect.Existing clustering algorithms,such as k-means(Jain&Dubes1988),PAM(Kaufman&Rousseeuw1990),CLARANS(Ng&Han1994),DBSCAN(Ester, Kriegel,Sander&Xu1996),CURE(Guha,Rastogi&Shim1998),and ROCK(Guha,Rastogi&Shim1999)are designed tofind clusters thatfit some static models.For example,k-means,PAM,and CLARANS assume that clusters are hyper-ellipsoidal or hyper-spherical and are of similar sizes.The DBSCAN algorithm assumes that all points of a cluster are density reachable(Ester et al.1996)and points belonging to different clusters are not. All these algorithms can breakdown if the choice of parameters in the static model is incorrect with regarding to the data set being clustered,or the model did not capture the characteristics of the clusters(e.g.shapes,sizes, densities).In the following,we give a brief overview of existing clustering algorithms.2.1Non-hierarchical SchemesNon-hierarchical clustering techniques are also called partitioning clustering techniques.These approaches attempt to construct a simple partitioning of a data set into a set of k non-overlapping clusters such that the partitions optimize a given criterion.Each cluster must contain at least one data element,and each data element must belong to exactly one group.In most of the partitioning methods an initial partitioning is chosen and then the cluster membership is changed in order to obtain a better partitioning.Centroid based methods like the k-means method(MacQueen1967),(Jain&Dubes1988)and the ISODATA(Ball&Hall1965)method try to assign data elements to clusters such that the mean square distance of data elements to the centroid of the assigned cluster is minimized.These techniques are suitable only for data in metric spaces,because they have to compute a centroid of a given set of data elements.Medoid based approaches as CLARANS(Ng&Han1994)and PAM(Kaufman& Rousseeuw1990)try tofind a so called medoid which is a representative data element that minimize the sum of the distances between the medoid and the data elements assigned to this medoid.One disadvantage of centroid and medoid based methods is that not all values of k lead to natural cluster so it is useful to run the algorithm several times with different values for k to select the best partition.With a given optimization criterion this decision can be automated.The main drawback of both methods is that they will fail for data sets in which data elements belonging to a cluster are closer to the representative of another cluster than to the representative of their own cluster.This case is typical for many natural clusters if the cluster shapes are concave or their sizes vary largely.2.2Hierarchical SchemesHierarchical cluster schemes constructs a dendrogram is a tree structure which represents a sequence of nested clusters.This sequence represents multiple levels of partitioning.On the top is a single cluster which includes all other clusters.At the bottom are the data elements representing single element clusters.Dendrograms can be constructed top-down or bottom-up.The bottom-up method is known as the agglomerative approach,where each data element starts out as a separate cluster.In each step of an agglomerative algorithm the two most similar clusters are grouped together based on similarity measures in subsequent steps and the total number of clusters is decreased by one.These steps can be repeated until one large cluster remain or a given number of clusters is obtained or the distance between two closest clusters is above a certain threshold.The top-down method known as the divisive approach works in the reverse direction.Agglomerative methods seems to be the most popular in the literature.In the literature one canfind many different variations of hierarchical algorithms.Basically, these algorithms can be distinguished by their definition of similarity and how they update the similarity between3GRAPH-BASED CLUSTERING3 existing clusters and the merged clusters.In general,the approaches described are alternative formulations or minor variations of the following three concepts:centroid or medoid based methods,linkage based methods,variance or error sum of squares error.The centroid or medoid based approaches also fail on clusters of arbitrary shapes and different sizes like non-hierarchical methods,such as k-means and k-medoid.The oldest linkage based method is the single linkage algorithm,sometimes referred to as the nearest neighbor approach.In the single linkage method, no representative exists.The cluster is represented by all data elements in the cluster and the similarity between two clusters is the distance between the closest pair of data elements belonging to different clusters.The single linkage method is able tofind clusters of arbitrary shape and different sizes,but it will fail at poorly separated clusters and is susceptible to noise and outliers.In order to avoid these drawbacks algorithms like the shared near neighbors method(Jarvis&Patrick1973),CURE(Guha et al.1998)or ROCK(Guha et al.1999)were proposed. Instead of using a single centroid to represent a cluster,CURE choose a constant number of representative points to describe a cluster.The ROCK algorithm operates on a derived similarity graph and scales the aggregate inter-connectivity with respect to a predefined inter-connectivity model.The shared near neighbors method use a k-nearest-neighbour graph to determine the similarity between two clusters.The advantage of this clustering method over most other alternatives is that it is independent of absolute scale.A major limitation of existing agglomerative hierarchical schemes such as the Group Averaging Method(Jain&Dubes1988),CURE,and ROCK is that the merging decisions are based on static modeling of the clusters to be merged.More information about the limitations of existing hierarchical methods can be found in(Karypis,Han&Kumar1999).3Graph-based ClusteringThe most powerful methods of clustering in difficult problems,which give results having the best agreement with human performance,are the graph-based methods(Jaromczyk&Toussaint1992).The idea is extremely simple: Compute a neighborhood graph(such as the minimal spanning tree)of the original points,then delete any edge in the graph that is much longer(according to some criterion)than its neighbors.The result is a forest and each tree in the forest represents a cluster.In general,hierarchical cluster algorithms work implicitly or explicitly on a similarity matrix such that every element of the matrix represents the similarity between two elements.In each step of the algorithm the similarity matrix is updated to reflect the revised similarities.Basically,all these algorithms can be distinguished based on their definition of similarity and how they update the similarity matrix.In spatial clustering algorithms one can discriminate between spatial similarity and semantic similarity which means the similarity of non-spatial attributes.Spatial Similarity implies the definition of a neighborhood concept which can be defined on geometric attributes,such as coordinate,distance,density,and shape.The computation of a spatial similarity matrix can be seen as the construction of a weighted graph,so called neighborhood graph,where each element is represented by a node and each neighborhood relationship(similarity)is an edge.3.1Neighbourhood GraphsA general introduction to the subject of Neighbourhood Graphs is given in(Jaromczyk&Toussaint1992).Neigh-bourhood graphs capture proximity between points by connecting nearby points with a graph edge.The many possible notions of nearby lead to a variety of related graphs.It is easiest to view the graphs as connecting points only when a certain region of space is empty.In our approach we use the following neighbourhood graphs:The Nearest Neighbour Graph(NNG)(Eppstein,Paterson&Yao1997,Nakano&Olariu1997,Jarvis&Patrick1973), the Minimum Spanning Tree(MST)(Yao1982,Supowit1983,King1995),the Relative Neighbourhood Graph (RNG)(Toussaint1980),the Gabriel Graph(GG)(Gabriel&Sokal1969),and the Delaunay Triangulation(DT) (Lee1980,O’Rourke1982,Preparata&Shamos1988).Figure1shows all these graphs for an example point set. The important relationship between these neighbourhood graphs is that they build a hierarchy:NNG⊆MST⊆RNG⊆GG⊆DT.4HPGCL-ALGORITHM4(a)Set of Points(b)NNG(c)MST(d)RNG(e)GG(f)DT Figure1:Modelling local to global neighbourhood.From left to right:Set of points,Nearest Neighbour Graph (NNG),Minimum Spanning Tree(MST),Relative Neighbourhood Graph(RNG),Gabriel Graph(GG),and De-launay Triangulation(DT).4HPGCL-AlgorithmIn our approach we use the hierarchical relationship between proximity graphs to represent a local to a global neighbourhood model.Thefirst step in our approach is the computation of all used neighbourhood graphs(DT, GG,RNG,MST,and NNG).Then we activate the edges of the NNG to start the most local neighbourhood.Then all given nodes(data that should be clustered)are initialized as a single cluster.In our model every cluster contains a set of inner edges and a set of outer edges.The inner edges connect nodes which belongs to the same cluster and the outer edges connect nodes which belongs to different clusters(figure2(a)).Every cluster is characterized by the median of the inner edge sizes(cluster density)and the cluster variance.the cluster variance is the absolute median deviation of all inner and outer edge sizes from the cluster density,which introduce an uncertainty model(tolarance interval)to our clustering approach.At the beginning every initial cluster has no inner edges and therefore a density of zero,but the variance will be none zero,because every node in the NNG belongs at least to one edge.All initial clusters are put into a priority queue,ordered by their density and variance values.Thefirst cluster in the priority queue is selected and merged with all of his valid neighbour clusters.Valid neighbour clusters X and Y are clusters which are connected by at least one outer edge and meet the following three constraints:Density compatibility (seefigure2(b)),Distance compatibility,which means that that the median distance between X and Y belongs to the tolerance intervals of X and Y,and Variance compatibility,which means that the variance of the merged cluster XY is at most the maximum variance of X and Y.From the priority queue all valid neighbours are removed and the new merged cluster is inserted.Then repeat the selecting and merging step until no more clusters with valid neighbours can be found.The result is the set of clusters based on the NNG.In the next step the edges of the MST are activated and the same selecting and merging procedure as for the NNG is repeated.Tis procedure is repeated for the edges of the RNG,GG,and the DT,which represents the most global neighbourhood.Figure 3shows the clustering result for an artificial test set with and without noise and for a3D laser scan data set.The data set shown infigure1(a)are the centroids of building groundplans.Infigure4the cluster results are shown if one is using only a single graph of the hierarchie andfigure5shows the different results if one is using the different subhierarchies.5ConclusionOne important operation for the cartographic generalization is the search for groups of neighboured objects.We have shown that neighbourhood graphs are a very good tool tofind such objects groups in a natural way without(a)Clusterdefinition(b)Density compatibilityFigure2:Figure(a):Green inner edges,red outer edges and yellow cluster border.Figure(b):A circle is the cluster density and an interval is the cluster variance.Cases I and II are compatible and the others are incompatible.(a)(b)(c)(d)(e)(f)Figure3:(a)artificial test set,(b)artificial test set with noise,(c)3D laser scan data.(d)(e)(f)results of the clustering method.(a)NNG(b)MST(c)RNG(d)GG(e)DTFigure4:Cluster result by using only a single graph.(a)NNG(b)NNG-MST(c)NNG-RNG(d)NNG-GG(e)NNG-DTFigure5:Cluster result by using the different graph hierarchies.need of any parameter.We think that more research should be investigated on the usage of neighbourhood graphs for map generalization,because neighbourhood graphs,like the Relative Neighbourhood Graph,can give us a good structural represantion of spatial objects.This structural information can be used tofind regular structures,which provides us with more cartographic meta information.ReferencesAnders,K.-H.(2003),Parameterfreies hierarchisches Graph-Clustering Verfahren zur Interpretation raumbezogener Daten,PhD thesis,Universit¨a t Stuttgart.Ball,G.&Hall,D.(1965),‘Isodata:a novel method of data analysis and pattern classification’,Stanford Research Institute AD699616.Eppstein,Paterson&Yao(1997),‘On nearest neighbor graphs’,GEOMETRY:Discrete&Computational Geometry17.*/eppstein97nearestneighbor.htmlEster,M.,Kriegel,H.-P.,Sander,J.&Xu,X.(1996),A density-based algorithm for discovering clusters in large spatial databases with noise,in‘Proceedings of2nd.International Conference on Knowledge Discovery and Data Mining(KDD-96)’.Gabriel,K.&Sokal,R.(1969),‘A new statistical approach to geographic variation analysis’,Systematic Zoology 18,259–278.Guha,S.,Rastogi,R.&Shim,K.(1998),Cure:An efficient clustering algorithm for large databases,in‘Proc.of 1998ACM-SIGMOD International Conference on Management of Data’.Guha,S.,Rastogi,R.&Shim,K.(1999),Rock:A robust clustering algorithm for categorical attributes,in‘Proc.of the15th International Conference on Data Engineering’.Jain,A.&Dubes,R.(1988),Algorithms for Clustering Data,Prentice Hall.Jaromczyk,J.&Toussaint,G.(1992),Relative neighborhood graphs and their relatives,in‘Proceedings IEEE’, Vol.80(9),pp.1502–1517.Jarvis,R.&Patrick,E.(1973),‘Clustering using a similarity measure based on shared near neighbours’,IEEE Transactions on Computers22(11),1025–1034.Karypis,G.,Han, E.-H.S.&Kumar,V.(1999),Chameleon:A hierarchical clustering algo-rithm using dynamical modeling.To appear in the IEEE Computer or via internet at /∼karypis/publications/data-mining.html.Kaufman,L.&Rousseeuw,P.(1990),Finding Groups in Data:An Introduction to Cluster Analysis,John Wiley &Sons.King,V.(1995),A simpler minimum spanning tree verification algorithm,in‘Workshop on Algorithms and Data Structures’,pp.440–448.*/king95simpler.htmlLee,D.(1980),‘Two dimensional voronoi diagram in the l p metric’,Journal of ACM(27),604–618. MacQueen,J.(1967),Some methods for classification and analysis of multivariate observations,in‘Proc.of the Fifth Berkeley Symposium on Mathematical Statistics and Probability’,Vol.1,pp.281–297.Nakano,K.&Olariu,S.(1997),‘An optimal algorithm for the angle-restricted all nearest neighbor problem on the reconfigurable mesh,with applications:’,IEEE Transactions on Parallel and Distributed Systems8(9),983–990.*/129316.htmlNg,R.&Han,J.(1994),Efficient and effective clustering method for spatial data mining,in‘Proc.of1994Int.Conf.on Very Large Data Bases(VLDB’94)’,Santiago,Chile,pp.144–155.O’Rourke,J.(1982),‘Computing the relative neighborhood graph in the l1and l∞metrics’,Pattern Recognition pp.45–55.Plazanet,C.,Bigolin,N.&Ruas,A.(1998),‘Experiments with learning techniques for spatial model enrichment and line generalization’,GeoInformatica2(4),315–334.Preparata,F.P.&Shamos,M.I.(1988),Computational Geometry,Springer-Verlag,New York.Richardson,D.(1996),‘Automatic processes in database building and subsequent automatic abstractions’,Carto-graphica,Monograph4733(1),41–54.Ruas,A.&Lagrange,J.(1995),Data and knowledge modelling for generalization,in J.-C.M”uller,grange &R.Weibel,eds,‘GIS and Generalization-Methodology and Practice’,Taylor&Francis,pp.73–90.Sester,M.(1999),‘Knowledge acquisition for the automatic interpretation of spatial data’,Accepted for Publication in:International Journal of Geographical Information Science.Sester,M.,Anders,K.-H.&Walter,V.(1998),‘Linking objects of different spatial data sets by integration and aggregation’,GeoInformatica2(4),335–358.Supowit,K.(1983),‘The relative neighborhood graph,with an application to minimum spanning trees’, put.Mach.30,428–448.Toussaint,G.(1980),‘The relative neighborhood graph of afinite planar set’,Pattern Recognition12,261–268.van Smaalen,J.(1996),‘Spatial abstraction based on hierarchical re-classification’,Cartographica,Monograph47 33(1),65–74.Yao,A.-C.(1982),‘On constructing minimum spanning trees in k-dimensional spaces and related problems’,SIAM put.(11),721–736.。
出国成绩单课程名称中英文对照参考表
外国文学作选读Selected Reading of Foreign Literature现代企业管理概论Introduction to Modern Enterprise Managerment电力电子技术课设计Power Electronics Technology Design计算机动画设计3D Animation Design中国革命史China’s Revolutionary History中国社会主义建设China Socialist Construction集散控制DCS Distributed Control计算机控制实现技术Computer Control Realization Technology计算机网络与通讯Computer Network and CommunicationERP/WEB应用开发Application ＆ Development of ERP/WEB数据仓库与挖掘Data Warehouse and Data Mining物流及供应链管理Substance and Supply Chain Management成功心理与潜能开发Success Psychology & Potential Development信息安全技术Technology of Information Security图像通信Image Communication金属材料及热加工Engineering Materials & Thermo-processing机械原理课程设计Course Design for Principles of Machine机械设计课程设计Course Design for Mechanical Design机电系统课程设计Course Design for Mechanical and Electrical System。
出国成绩单课程名称中英文对照参考表
Art and Appreciation ⑴ ⑵ ⑶ ⑷
设计透视学㈠㈡
Design Scenograph ⑴ ⑵
设计素描㈠㈡
Design Sketch ⑴ ⑵
设计色彩方法学㈠㈡
Design Chromatology ⑴ ⑵
工程及计算机制图㈠㈡
Engineering and Computer Cartography ⑴ ⑵
科研成果
Achievements of Researches
金工实习
Practice of Metal Machining
模型制作课程设计
Course Design for Model Making
文献检索与利用
Search ＆ Utilization of Literature
小产品造型测绘
Little Product Modeling and Mapping
电子技术
Electronic Techniques
微机原理及应用
Microcomputer and its Applications
工程材料及热加工
Engineering Materials ＆ Thermo-processing
材料力学
Mechanics of Materials
机械原理
Principles of Machine
军训
Military Training
形势与政策
Current Situation and Policies
课外读书活动
Reading Project Out of Class
社会实践
Social Practice
讲座
Serial Lectures
数据通信英语作文
数据通信英语作文Nowadays, data communication has become an essential part of our daily lives. Nowadays, data communication has become an essential part of our daily lives. (如今，数据通信已经成为我们日常生活的一个重要组成部分。
The importance of data communication can be seen in various aspects of our lives, from the way we interact with our loved ones to the way businesses operate. 数据通信的重要性在我们生活的各个方面都可以看到，从我们与亲人互动的方式到企业运营的方式。
In our personal lives, data communication allows us to stay connected with our friends and family no matter where they are in the world. 在我们的个人生活中，数据通信让我们能够与朋友和家人保持联系，无论他们身在何处。
Through social media platforms, instant messaging apps, and video calls, we are able to share our experiences, emotions, and memories with the people we care about, bridging the physical distancesbetween us. 通过社交媒体平台、即时通讯应用和视频通话，我们能够与我们关心的人分享我们的经历、情感和回忆，弥合我们之间的物理距离。
面向大数据通信的隐私保护与加密算法研究
通信网络技术面向大数据通信的隐私保护与加密算法研究马逸群（内蒙古自治区大数据中心，内蒙古呼和浩特文章围绕大数据通信的隐私保护与加密算法展开研究，旨在解决大数据通信中存在的安全挑战，提高信息传输的隐私保护水平。
通过对现有隐私保护技术和加密算法的概述，深入探讨数据匿名化、访问控制与身份验证、差分隐私技术等隐私保护方面的研究，并优化研究对称加密算法、非对称加密算法、混合加密方案等，以提高其在大数据通信中的效率和安全性。
通过技术的实现与性能评估，验证文章所提出的隐私保护技术的可行性和实用性，为大数据通信安全提供一定的理论和技术支持。
大数据通信；隐私保护；加密算法Research on Privacy Protection and Encryption Algorithms for Big Data CommunicationMA Yiqun(Inner Mongolia Autonomous Region Big Data Center, Hohhotresearch of privacy protectionof big data communication, aiming to address the security challenges existing in large-scale data transmission and份或敏感信息，从而降低隐私泄露的风险。
数据匿名化的核心目标是在保持数据可用性的同时，最大限度地降低个体身份的可识别性。
常见的数据匿名化方法是泛化和抑制。
泛化通过模糊化或一般化特定属性的值，从而降低特定用户的可识别性；抑制则通过删除或替换部分敏感数据，以达到降低隐私风险的目的。
种方法可以结合使用，形成一套完整的数据匿名匿名为例，它是一种基于泛化的匿名化技术，通过将某个属性的值泛化为相同的值，确保个相同属性值的记录，从而实现对个体的的数据集，上的值都相同，并且，那么这些记录就被认为2.3 差分隐私技术差分隐私技术是一种有效的隐私保护手段，主要应用于数据处理和发布场景。
INTERCEPTION AND FURTIVITY OF DIGITAL TRANSMISSIONS
INTERCEPTION AND FURTIVITY OF DIGITALTRANSMISSIONSGilles BUREL1, André QUINQUIS2, Stéphane AZOU3 Abstract: The development of digital communications creates new challenges for spectrum surveillance. Similarly, modern signal processing techniques and increasing available computational power make communication discretion ever more difficult. In this paper, we present recent methods based on time-frequency analysis and on statistical analysis of fluctuations, that are useful for detection and identification of transmissions in a non-cooperative context. Furthermore, promising research concerning the use of chaotic signals to develop furtive transmission systems is also presented.Keywords: Digital transmissions, Interception, Time-frequency analysis, Furtivity, Chaos, Spectrum surveillance, Spread spectrum, Unscented Kalman filtersI.IntroductionThe proliferation of high performance digital transmission devices has enhanced the role of collecting and securing information in order to provide intelligence on the enemy's intentions and capabilities without revealing one's own intentions. The modern concept is that interception and furtivity of transmissions is an important part of an overall military strategy which concentrates on collecting information through interception of enemy communications while maintaining the capability of discretely operating one's own data transmissions.However, these considerations are not restricted to the military domain. Indeed, the development of wireless transmissions (e.g. wireless indoor domestic networks or cellular telephones) points out the need of mastering interception techniques (to protect transmissions, or for spectrum surveillance) as well as the need of research on furtive and secure transmissions.In this paper, we present an overview of some researches about interception and furtivity of transmissions developed in our laboratory.In Section 2, we show how modern mathematical tools such as time-frequency analysis, can be adapted for the detection and analysis of classical narrow band digital transmissions. Experimental results show that a high attenuation of interferences can be obtained, thus enhancing discrimination capabilities.However, digital transmissions are not always narrow-band. Indeed, a technique that is often used to hide transmissions in noise is spread spectrum. In Section 3, we show that spread spectrum signals can be detected and demodulated in a non cooperative context, even at a very low signal to noise ratio. Once demodulated, the spread spectrum signal becomes narrow-band, and techniques presented in Section 2 can be used for further analysis.1 L.E.S.T. - UMR CNRS 6165, Université de Bretagne Occidentale, BP 809, 29285 BREST cedex, FRANCE, Gilles.Burel@univ-brest.fr2 L.E.S.T. - UMR CNRS 6165, ENSIETA, rue François Verny, 29806 BREST cedex 09, FRANCE, Andre.Quinquis@ensieta.fr3 L.E.S.T. - UMR CNRS 6165, Pôle Universitaire Per Jakez Helias, Creac'h Gwen, 29000 QUIMPER, FRANCE, Stephane.Azou@univ-brest.frFrom the opposite point of view, the existence of methods to detect and analyze classical digital transmissions points out the need to develop new modulations, in order to transmit signals which are more difficult to intercept. One promising idea is the use of chaotic signals produced by non-linear oscillators, as detailed in Section 4.Hence, our research has two complementary objectives: being able to detect and analyze digital transmissions, and, simultaneously, ensuring highest discretion of one’s own transmissions.II.Detection and analysis of narrow-band signalsIntroduction Nowadays digitally modulated signals such as ASK (Amplitude Shift Keying), PSK (Phase Shift Keying) among others are very important for telecommunications systems. Such signals can be found in many civilian as well as military applications such as: interference identification and spectrum management, identification of non-licensed transmitters,electronic warfare, surveillance and threat analysis, control of communication quality, etc.In COMmunication INTelligence (COMINT) applications, the modulation types are considered as signal signatures. Therefore, the modulation recognition is an essential key to demodulate as well as to decode and understand the transmitted message.In the last two decades, many researchers have been interested by automatic recognition and identification algorithms for communication signal. In fact, since 1990, many algorithms have been proposed [3]. The main differences among these algorithms are their sensitivity to Signal to Noise Ratio (SNR), the type of modulation that they can deal with, and the applications where they can be used.Generally, modulation algorithms consist of various steps depending on the field of interest. First of all, if we are only interested in modulation types, a simple modulation classifier can deal with this case. Once the modulation type has been classified, one may seek other features for signal identification purpose. For example, one can seek for a state number,a symbol duration among others.To distinguish the different versions of modulation, algorithms often enclose the computation of state number. For instance, many studies aim at distinguishing the different MPSK or the different MFSK versions [15]. With regard to the symbol duration, we can quote the methods based on the level crossing, the derivation or a wavelet transform, for example.On the other hand, it seems that the carrier frequency is a main feature in many applications.Most of the Frequency-domain estimation methods are based on the signal spectrum.The performances of such methods depend on the estimation techniques (Welch, …) and the estimation window (such as Hamming, Hanning, …). Indeed, the experimental studies show that this technique is sensitive to noise. To increase the robustness of the approach, new methods based on recent developments are possible.Time frequency distributions (TFD)Most TFDs of current interest are members of Cohen’s bilinear class which can be generated by Fourier transformation of a weighted version of the ambiguity function (AF) of the signal to be analyzed. That is, if TFR(t,f) is a bilinear TFD of the signal x(t), thenwith A(W ,F) the ambiguity function of the signal:)1(2,,,³³ fdF d Ft f j e F F A f t TFR W W S W I WIf I (W ,F)=1 we obtain the classical Wigner-Ville distribution (WVD). Different choices of the kernel function I are possible to obtain many TFDs. In recent years, it has become apparent that no single kernel can give adequate performance for a large class of signals; hence, there has been increasing interest in signal-dependent or adaptive TFRs (ATFRs). It was proposed [4] an ATFR based on kernels with Gaussian radial cross sections:¸¸¹·¨¨©§ )\V \222exp ,r r The function V (\) controls the spread of the Gaussian at radial angle \ ; we will call V (\) the spread function. The angle \ is measured between the radial line through the point (W ,f) and the W axis: W \f arctan.A high quality time-frequency representation results when the kernel is well matched to the component of a given signal. The radial Gaussian kernel is adapted to a signal by solving the following optimization problem: ³³f ))S \\\2002,,max rdrd r r A where \,r ) is subject to :³³³f t d )S S D D \\V S\\S 2002022220,41,41d rdrd r By focusing the volume under the optimal kernel, the parameter D controls the trade-off between interference suppression and smearing of the auto-components.The shape of a radial Gaussian kernel is completely parameterized by the spread function; so, finding the optimal kernel )opt for a signal is equivalent to find the optimal function V opt (\) for the signal. The algorithm includes four stages (Fig. 1)In the first stage, the AF of the signal is computed. In the second stage the optimization problem is solved for the optimal kernel. Next, we compute the product between AF of the signal x and )opt obtained as result of the second stage. Finally, we compute the bi-dimensional Fast Fourier Transform (FFT2D) in order to obtain the adaptive time-frequency distribution of the signal x .This distribution has many attractive qualities; the most important (in this context) is the time-frequency interference suppression. So, we may imagine many applications, such as the time-frequency signal analysis or the signal classification using the most adapted kernel function as a discriminative element.The limitation of this method is that it designs only one kernel for the entire signal. So,for signals with characteristics that change over time, it is necessary to use a procedure that)2(222*,dt Ft j e t x t x F A ³¸¹·¨©§ ¸¹·¨©§ S W W Wadapts the kernel each time in order to achieve optimal local performance. Moreover, the choice of the parameter D is another problem that appears in practice.To obtain the optimal local performances, we apply this procedure on short slide window over the signal. That is, we adapt the kernel for all the sequences obtained by windowing. Let us name this new transformation as «Short ATFR». Furthermore, we prefer the use of this transform, because it is well adapted for real-time problem.Comparative resultsIn order to compare the presented method with the classical TFRs we consider an FSK signal (Frequency Shift Keying) with eight frequency steps, presented in figure 2. We show also his ideal time-frequency distribution.In figure 3, we show the results obtained by applying the described time-frequency distributions and we observe the superior performance of the ATFR. The SPWVD (Fig. 3.a)precludes some interference terms, but affects the time-frequency support which is not well conserved. Another problem with this distribution is the choice of the smoothing windows,that is hard in practice. Moreover, between atoms 3 and 4, respectively 5 and 6 strong interference terms appear. The same comment can be formulated when using CWD (Fig. 3.b).Even if CWD uses a kernel with Gaussian shape (like ATFR), the results are unwell, because this kernel has a fixed position in the ambiguity plane, unadapted to the signal.a b dc Fig. 2: FSK signal and its idealtime-frequency representation Fig. 3 - Comparison of time-frequency distributions. From left to right and top tobottom: (a) Smoothed pseudo Wigner-Villedistribution with g window width 33 and hwindow width123; (b) Choi Williams distributionwith smoothing parameter V =3.5; (c) ATFR withD =2; (d) Short ATFR of volume D =25 andwindow width 32The results obtained by the ATFR use denote the quality of this transformation: ATFR precludes almost all interferences and better preserves the time-frequency support (Fig. 3.c).Ideally, a TFR should have the same nonzero support, i.e., duration and bandwidth, as the signal under analysis. These properties state that if a signal starts at time t 1 (and at a frequency f 1) and stops at time t 2 (and frequency f 2), then an ideal TFR should start and stop at the same time-frequency point. These properties ensure the fidelity of the signal approximation in the time-frequency plane. Furthermore, we can accurately estimate the signal characteristics.In order to evaluate the support conservation capability of the TFR, a set of quality parameters is introduced :1) Degree of time support conservation (DTSC): this parameter is defined for a certain time-frequency atom and represents the time support of this atom. We prefer to use the DTSC normalized at the support of entire signal. That is : Tdt TSCn D where dt is the temporal support and T is the number of samples of the signal.2) Degree of frequency support conservation (DFSC): this parameter is defined as thefrequency support of a time-frequency atom; we prefer to use the DFSC normalized at thesampling frequency (F s ). sF df DFSCn 3) Interferences attenuation factor (IAF): this parameter represents a quality measure of the interference time-frequency suppression, defined by iu E E IAF where E u is the energy of auto-terms and E i the energy of interference terms. In the ideal case, this factor must be f .Table 1 shows the obtained parameters for each transformation, as well as their ideal values. We observe the high performances of the short ATFR, provided by the kernel adaptation over time. In figure 3.d we demonstrate the superiority of Short ATFR facing ATFR (that computes a single kernel for the entire signal).TFRsDTSCn DTFCn IAF Ideal0.1250f Smoothed pseudo Wigner-Ville0.09470.029 1.5Choi-Williams0.10.034 1.02ATFR0.05120.022 3.1Short ATFR 0.08930.011157.27Table 1 - Time-frequency distribution performancesWe observe the superior performances of the ATFR facing classical interference terms suppression methods, but its quality is poorer than the short ATFR; this result illustrates the benefits of the kernel time adaptivity.ConclusionThe novel approach precludes almost all the interference terms and, simultaneously,better keeps the time and frequency resolution. There are two major drawbacks: first, the choice of the kernel volume parameter is sometimes difficult to do and supposes more knowledge about the signal spreading in time and frequency. On the other hand, the adaptive Gaussian kernel designed in the ambiguity plane works only with signals having multiple components of the same nature.Furthermore, we can improve the performances of this approach using the locally kernel design. Our future work will be devoted to this, by experimenting the time-frequency distributions using adaptive signal expansion for the linear modulations, and using the warping operators for the non-linear ones.III. Interception of hidden spread spectrum transmissionsIntroductionSpread spectrum signals have been used for secure communications for several decades. Nowadays, they are also widely used outside the military domain, especially in Code Division Multiple Access (CDMA) systems [12]. Due to their low probability of interception,these signals increase the difficulty of spectrum surveillance.Direct-Sequence Spread Spectrum transmitters (DS-SS) use a periodical pseudo-random sequence to modulate the baseband signal before transmission. In the context of spectrum surveillance, the pseudo-random sequence used by the transmitter is unknown (as well as other transmitter parameters such as duration of the sequence, symbol frequency and carrier frequency). Hence, in this context, a DS-SS transmission is very difficult to detect and demodulate, because it is often below the noise level.The research work developed in our laboratory aims at:1. detecting the presence of a spread spectrum transmission in a non-cooperative context2. then, estimating the transmitter parameters (including its spreading sequence).Once the spreading sequence has been estimated, a classical spread-spectrum receiver can demodulate the signal.Blind detection of a spread spectrum transmissionIn a DS-SS transmission, the symbols a k are multiplied by a pseudo-random sequence which spreads the bandwidth. At the output of the receiver filter, the downconverted signal is:)()()()()(t n kT t h a t n t s t y s k k ¿¾½¯® ¦ f f where s(t) is the spread-spectrum signal (variance 2s V ), n(t) is the noise (variance 2n V ),and h(t) stands for the spreading waveform (more precisely, it is the convolution of the pseudo-random sequence with the transmission filters and the channel).In a cooperative context, the pseudo-random sequence, as well as the carrier and symbol frequencies, are known by the receiver. The receiver correlates the received signal with the pseudo-random sequence, in order to retrieve the symbols. In a non-cooperative context, these parameters are unknown. Furthermore, classical second order detection methods are useless, because the autocorrelation function of a DS-SS signal is similar to the autocorrelation of a white noise. The method we have developed for blind detection of a DS-SS transmission hidden under the noise level is based on fluctuations of correlation estimators[6]. The received signal is divided into non-overlapping windows of duration T (the exact value of T does not matter; ideally, the window should contain a few symbols, but the methods works over a large range of values). Within each window, we compute an estimation of the correlation:dtt y t y T R Tm yy )()(1)(ˆ*0)(W W ³where m is the window's index. Using M windows, we can estimate the second order moment of the estimated autocorrelations:¦ M m m yy R M 12)()(ˆ1)(W W U This is a measure of the fluctuations of the autocorrelation estimator.If no signal is hidden in the noise (i.e. y(t)=n(t) ), we can predict the average value and standard deviation of the fluctuation curve U (W ). For simplicity, let us consider the case of a receiver filter with flat frequency response in [-W /2, +W /2] and zero outside. In that case, we can prove [6] that the theoretical average value and standard deviation of the fluctuations are:4)(1n n TWm V U Mm n n )()(UU V Hence, is no signal is hidden in the noise, the curve U (W ) should remain around )(n m Uand has a very low probability to go above )()(4n n m U U V .If a signal is hidden in the noise, we can prove that its contribution to the fluctuation curve is negligible, except for values of W which are multiples of the symbol period. In this later case, the average value of its contribution is:4)(s s s TT m V U Then the ratio between the mean value of the peaks created by the DS-SS signal (if there is one such signal hidden in the noise), and the standard deviation of the fluctuations due to the noise is:44)()(2ns s n s W T M m V V V U UThe reader must not be surprised to see a ratio between a mean and a standard deviation: indeed, it is this ratio which is significant to determine if the peaks due to the DS-SS signal may be hidden by the fluctuations due to the noise (see the display below). This equation shows that the performances of our method can always be improved by increasing the number of windows M (at the expense of longer computation time).Figure 4 shows an example of the detector output. The curve represents U (W ) (i.e. the fluctuations of the correlation estimator), as a function of W (in P s ). The two horizontal linesshow )(n m U (the predicted average value of the fluctuation if noise only were present) and )()(4n n m U U V .Fig. 4 - Example of detector output We can clearly see that peaks are present, and that they go far above the theoretical upper bound. Hence, there is no doubt that a spread spectrum signal is hidden in the noise.Indeed, there was, here, a signal hidden 8dB below the noise level. Furthermore, the distance between the peaks provides an estimation of the symbol period Ts.180190200210220230240250260005115225fluctuations: rho(tau)m oy. theorique (bruit seul)m ax . theorique (bruit seul)Blind estimation of the spreading sequenceOnce a spread spectrum transmission is detected, the problem is to estimate the spreading sequence. The method we have developed is based on eigenanalysis techniques.The received signal is divided into temporal windows, the size of which is the symbol period (this period has been estimated from the distance between the peaks on the fluctuations curve). Each window provides a vector which feeds the eigenanalysis module. Let us carefully examine the structure of the signal (Fig. 5). Since the window duration is equal to the symbol period, a window always contains the end of a symbol (for a duration T s – t 0 ),followed by the beginning of the next symbol (for a duration t 0), where t 0 is an unknown desynchronization. Hence, the presence of the signal will contribute to align the subspace spanned by the first and second eigenvectors with the subspace spanned by vectors 0h & and 1 h &shown on figure 6.One method [7] consists in trying to identify these vectors from the subspace: the sequence can be reconstructed from the two first eigenvectors, and that useful information,such as the desynchronization time, can be extracted from the eigenvalues. Another, slower,but more robust method [5], consists in first performing a blind synchronization (the criteria is maximization of the first eigenvalue), and then estimating the spreading sequence from the first eigenvector.S Analysis window (+ noise) T S - t 0t 0beginning ofwaveformh 0h -1Fig. 5 - Structure of the signal Fig. 6 - Generating vectorsExperimental results show that the method can provide a good estimation, even when the received signal is far below the noise level. Fig. 7 shows the estimated and true sequences.It is clear that the binary sequence can be recovered from the sign of the estimation. Here, the signal was hidden 8dB below the noise.-2.5-2-1.5-1-0.50.511.522.500102030405060708séquence estimée voie I -1.5-1-0.50.511.500102030405060708sequence de reference: voie I Fig. 7 - Estimated spreading waveform (top) and true spreading sequence (bottom)IV.Furtive transmissions based on chaotic signals IntroductionSince the results of Pecora and Caroll [14] about the synchronization capabilities of chaotic systems, there has been tremendous interest worldwide in the possibilities of exploiting chaos in communication systems. Due to its random-like behavior and its wideband characteristics, a chaotic dynamical system can be very helpful for discretion purposes. Chaos not only spreads the spectrum of the information signal but also acts as an encryption key. Thus, without knowledge of the type of nonlinearity on which the transmission is based (the chaotic dynamic), it will be extremely difficult for the unauthorized user to access the information. Furthermore, such signals are potentially robust against channel imperfections such as multipath propagation or jamming. As a result of their sensitive dependence on initial conditions, chaotic systems are able to produce large sets of uncorrelated signals. This extreme sensitivity can be demonstrated by giving two very close initial states to a chaotic map ; After a few iterations, the two resulting sequences will look completely decorrelated. This can be observed even for very simple (one-dimensional discrete-time) chaotic dynamical systems. The large signal set generated is an attractive feature in a multiple access transmission context. Another advantage of a chaos-based communication system is a less complicated circuitry in comparison with conventional spread spectrum approaches. Consequently, the weight and volume requirements of the devices are reduced and efficiency is increased. It may be possible to put a complete transmitter or receiver on one small chip.Currently, most of the previously mentioned advantages are only projected advantages, as noted in [17]. Nevertheless, the spectacular success of the recent research on communications with chaos is strong evidence that future nonlinear devices will actually have many of these advantages.Methods for chaos-based digital communicationsMany different chaotic modulations have been proposed since the work of Pecora and Caroll. These techniques may be classified into the following main families : Chaos Shift Keying (CSK), Differential CSK (DCSK), Chaotic Masking, Direct-Sequence/Frequency Hopping Spread Spectrum, Predictive Control and Chaotic Pulse Position Modulation. Some of these methods are overviewed in [8][9]. A detailed explanation is available in [16].In a chaos-based digital communication system, the information to be transmitted is mapped to chaotic waveforms. As in conventional communication schemes, the transmitted symbols are recognized at the receiver using either coherent or noncoherent demodulation techniques. The first solution is based on a chaotic synchronization process, in order to recover the original chaotic signal from the noisy received signal. To do so, a precise knowledge about the transmitter is required, including its chaotic dynamic. Conversely, a noncoherent demodulator relies on statistical properties of the received signal only. Such an approach has the advantage of robustness against channel imperfections (noise, multipath, Doppler) but it is not particularly suited for discretion purposes, as a limited knowledge about the transmitter is sufficient to recover the data symbols.As demonstrated in [14], in the noise-free case, two coupled identical chaotic systems (the master and the slave) are able to synchronize, that is the slave will asymptotically reproduce the driving signal, for arbitrary initial conditions. However, in practice, we have to cope with disturbed channels or parameter mismatch between chaotic oscillators. As a consequence, a perfect synchronization becomes impossible and even a rough approximationof the original signal is not that easy. Moreover, the synchronization is lost and recovered (partially) every time the transmitted symbol is changed.Usually, a low signal-to-noise ratio is a necessary condition to secure the transmission. For practical applications, the modulation scheme and especially the chaotic synchronization method have to be chosen carefully to avoid severe performance degradations in this context. We believe that chaotic Direct-Sequence Spread Spectrum (DS-SS) [10] or Chaotic Pulse Position Modulation (CPPM) [18] are very promising methods to succeed in getting competitive well secured digital communication systems. These two approaches allow multiple users to operate simultaneously in time over the same frequency band by using chaotic codes (Code Division Multiple Access).Chaotic Direct Sequence Spread Spectrum transmission systemA Chaotic DS-SS (CD3S) transmitter has a structure similar to that encountered in a standard DS-SS transmitter. The only difference is that the pseudo-noise (PN) code is replaced with a chaotic code. Hence, each data symbol is multiplied by a different portion of the spreading code, due to its aperiodicity. A possible structure for a CD3S transmitter is illustrated by figure 8. Here, chaotic markers, whose length is identical to the processing gain (number of chips of the spreading sequence per data symbol), are regularly inserted in order to synchronize the receiver. The wideband chaotic signal is then upsampled and a shaping filter is applied before modulating a sinusoidal carrier.Fig. 8- Block diagram of a Chaotic DS-SS transmitterA recent study carried out in our laboratory, about communicating with a CD3S system underwater [1], have led to encouraging results. Two demodulators currently under investigation are described below.x Master-Slave CD3S demodulator (Fig. 9):Though very basic, this kind of demodulation, initially proposed by Milanovic et al. [13], performs well if the spreading chaotic map is properly selected (favorable correlation properties). Here, the original spreading code is estimated owing to a master-slave coupling. Then, symbol decision is just given as the sign of the output of a correlator, operating over symbol duration. Figure 11 shows the Bit Error Rate performance of this demodulator on an Additive White Gaussian Noise (AWGN) channel.x Dual Unscented Kalman Filtering (UKF) CD3S demodulator (Fig. 10): This original scheme, detailed in [2], uses recent results on state space adaptive filtering [11] to achieve the chaotic synchronization. A dual estimation algorithm is implemented to track simultaneously the state of the received chaotic signal and the corresponding dynamic model (the symbol is an unknown parameter of the dynamic model). Symbol decision is。
信息通信与网络技术基础总结
1.Data communication is the exchange of data between devices via some form of transmissionmedium.2.Data communication system components are message, sender, receiver, medium and protocol. Protocol is a set of rules that govern data communicationMessage is the information (data) to be communicated.Sender is the device that sends the data message.Receiver is the device that receives the messageMedium is the physical path by which a message travels from sender to receiver3. A network is a set of devices (often referred to as nodes) connected by media links4.Reliability:frequency of failurerecovery time after a failurecatastrophe5. A protocol is a set of rules that govern data communication.the key elements of a protocol are :syntaxsemanticstiming6.Standards:De facto/by factDe jure/by law7.ISO: The International Standards OrganizationITU-T: The International Telecommunication Union-Telecommunication Standards SectorANSI: The American National Standards InstituteIEEE: The Institute of Electrical and Electronics EngineersEIA: The Electronics Industries Association8.Line configuration:Point-to-point: wired or wirelessMultipoint9.Topology: Mesh Star Bus Tree RingPeer-to-peer: The devices share the link equallyPrimary-Secondary: Where one device controls traffic and the other must transmit throughitPeer-to-peer: Mesh Ring BusPrimary-Secondary: Star Tree Bus10.Transmission Mode: Simplex Half-duplex Full-duplexSimplex mode: one station can transmit, the other can only receiveHalf-duplex mode: Each station can both transmit and receive, but not at the same time.Full-duplex mode: Both stations can transmit and receive simultaneously11.The Open System Interconnection(OSI) model is a layered framework for the design of networksystem that allows for communication across all types of computer systems.OSI model has 7 layers: Physical Data link Network Transportation Session Presentation Application12.Peer to peer processes: The processes on each machine that communicate at a given layer arecalled peer-to-peer processes.This communication is governed by an agree-upon series of rules and conventions call protocolsThe 7 layers are divided into 3 groups:the network support layers(1,2,3)user support layers(5,6,7)link the above subgroups(4)13.fig.3.3The process starts from layer 7, then move from layer to layer in descending sequential order,at each layer (except 7 and 1) a header is added. At layer 2 a trailer is added as well.14.Physical layers:Line configurationData transmission modeTopologySignalsEncodingInterfaceMedium15.The Physical layer coordinates the hardware and software functions required to transmit a bitstream over a Physical medium.It deals with a mechanical and electrical specifications of the primary connectionsThe data link layer is responsible for delivering frames from one station to the next with outerrors.It provides error handling and flow control between one station and the next.The network layer is responsible for the source-to-destination delivery of a data packet.It handles switching and routingThe transport layer is responsible for the source-to-destination (end-to-end) delivery of theentire message from one application to another.The session layer is the network dialog controller.It establishes, maintains, and synchronizes the interaction between communicating devices.The presentation layer ensures interoperability among communicating devices.To transact, encrypt, and compress dataThe application layer enables the user, whether human or software, to access the network.16.Bipolar: AMI B8ZS HDB321.PCM four processes:PAM quantization binary encoding digital encoding22.A/DPAM: Pulse Amplitude ModulationPCM: Pulse code Modulatio23.Nyquist 采样定理： f >= 2 f_max24.D/A encoding: ASK FSK PSK QAM25.Bit rate (比特率) is the number of bits per second (bps)Baud rate (波特率) is the number of signal units per second.ASK baud rate = bit rate = bandwidth (带宽)FSK bandwidth = fc1 - fc0 + Nbaud(波特率)26.A diagram called constellation or phase-state diagram is used to show the relationshipbetween phase in PSK27.Data transmission: Parallel Serial (Asynchronous Synchronous)28.Parallel transmission:use n wires to send n bits at one time.In Serial transmission:one bit follows another, so we need only one communication channel rather than n In Asynchronous transmission mode:start bit (0) stop bit (1) gapsIn Synchronous transmission mode:we send bits one after another without start/stop bit or gaps.It is responsibility of the receiver to group the bits into meaningful frames.29.A DTE is any device that is a source of or destination for binary digital data.A DCE is any device that transmits or receives data in the form of an analog or digital through anetwork.DTE-DCE standards try to define the mechanical, electrical and functional characteristics of connection between the DTE and DCE.30.EIA-530 standard is a version of EIA-449 that uses DB-25 Pins.31.Modem is the most familiar type of DCE.Modem stands for modulator/ demodulator.A modulator converts a digital signal to an analog signal.A demodulator converts an analog signal to a digital signal.32.Intelligent modem contain software to support a number of additional functions, such asautomatic answering and dialing.33.Transmission media : Guided media Unguided mediaGuided media: twisted-pair cable, coaxial cable fiber-optic cableUTP: Unshielded Twisted-pairSTP: Shielded Twisted-pair34.Propagation mode: Multimode Single modeMultimode: Step-index Graded-index35.光纤优点：noise resistance, less signal attenuation, higher bandwidth缺点：cost much, hard to installate/maintain, fragility easy broken than wire36.Multiplexing is the set of techniques that allows the simultaneous transmission of multiplesignals across a single data linkA Path refers to a physical link.Channel refers to a portion of a path that carries a transmission between a given pair of devices.Multiplexing: Frequency-division multiplexing(FDM)Time-division multiplexing(TDM)TDM: Synchronous Asynchronous37.In FDM, channels must be separated by trips of unused bandwidth to prevent signals fromoverlapping.Definition:FDM is an analog technique that can be applied when the bandwidth of a link is greaterthan the combined bandwidth of the signal.TDM is a digital process that can be applied when the data rate capacity of thetransmission medium is greater than the data rate required by the sending and receiving devices.38.Errors: Single-bit-error, Multiple-bit error, burst-errorError detection and correction is done by the data link layer or transport layer.Single-bit errors is when only one bit in the data unit has changed.Multiple-bit error is when two or more nonconsecutive bits in the data unit have changed.Burst error means that two or more consecutive bits in the data unit have changed.39.Redundancy means adding extra bits for detecting errors at the destination.Redundancy check(冗余校验): VRC, LRC, CRC, checksumVRC: Vertical Redundancy Check(垂直冗余校验)LRC: Longitudinal Redundancy Check(纵向冗余校验)CRC: Cyclical Redundancy Check(循环冗余校验)VRC, LRC, CRC is implemented in physical layer, used in data link layerChecksum is primarily used by networks, including the internet, and is implemented in the transport layer.1.In VRC a parity bit is added to every data unit so that the total number of 1s(including Paritybit) becomes even for even-parity check or odd for odd-parity check.VRC can detect all single-bit errors. It can detect multiple bit or burst errors only if the total number of errors is odd.2.In LRC, a redundant unit is added after a number of data units.3.In CRC a sequence of bits, called the CRC or the CRC remainder is appended to the end of adata unit, so that the resulting data unit becomes exactly divisible by a second, predetermined binary number.40.ApplicationPresentationSessionTransportNetworkData link : Line discipline Flow control Error controlPhysicalLine discipline: Who should send now?Flow control: How much data may be sent?Error control: How can errors be corrected?41.Line discipline: ENQ/ACK Poll/SelectEnquiry/acknowledgement: ENQ/ACK.is used in peer to peer communication, where there are dedicated link between two devicesMAC 定义: Media access control is the lower sub layer of the data link layer.51.802.3 defines two categories of LAN :Baseband Digital Broadband Analog52.CSMA/CD : Carrier Sense Multiple Access with Collision Detection is the result of anevolution from MA to CSMA to CSMA/CD.53.[ 10Base5 ] 10-10Mbps Base-Baseband 5-500meters10Base-T, a star-topology LAN using unshielded twisted pair(UTP) cable instead of coaxial cable.54.Token ring(令牌环网) allows each station to send one frame per turn.Each situation may transmit only during its turn and may send only one frame during each turn.The mechanism that coordinates this rotating is called token passing.55.FDDI: Fiber Distributed Data Interface.（光纤分布式数据接口）FDDI is a local area network protocol standardized by ANSI and the ITU-U.It supports data rates of 100 Mbps.56.4B/5B: FDDI uses a special encoding mechanism called four bits/five bits (4B/5B). Each for-bitsegment of data is replaced by five-bit code before being encoded in NRI-I4B/5B encoding mechanism is designed to avoid long sequence of 0s.57.Switching methods: circuit Packet Message switchingCircuit switching: Space-division switching Time-devising switching58.TSI(Time-Slot Interchange)作用The main component of time-division switching is a device called a time-slotinterchange(TSI).In TSI time slot are sent out in an order based on the decision of a control unit.59.Packet switching: Datagram approach virtual circuit approach60.X.25 is a packet switching protocol used in a wide area networkX.25 is an interface between data terminal equipment and data circuit terminating equipment for terminal operation at the packet mode on public data networks.61.the relationship of X.25 and OSINetwork: Packet layer protocol (PLP)Data link: Link access procedure balanced(LAPB)Physical: EIA-232 V-Series X-Series othersplete packet sequenceD = 1: the packet requires an acknowledgement from final destinationD = 0: no acknowledgement is needed.M = 1: 后面有包M = 0: 后面没包63.connecting devices:workingi.Repeaters: physical layerii.Bridges: 1、2 层b.Internetworkingi.Routers: 1、2、3层ii.Gateways: 1~7层64.A bridge divide a large network into smaller segments.They have access to station addresses and can forward or filter a packet in a network.65.Gateways operate in all seven layers of the OSI model.They covert one protocol to another and can therefore connect two dissimilar networks.。