|
|
发表于 2010-1-14 12:31:40| 字数 9,067| - 中国–天津–天津 电信
|
显示全部楼层
|阅读模式
无线传感器网络，是一门非常有发展前途的前沿技术。之所以前沿，是因为这个观点虽然68年就有人提出，但当时的理论和技术实现不了。近20年随着芯片技术和网络路由的进化才逐渐变“热”的。
它综合了传感器技术（物理、生化探测）、超低功耗无线技术（802.15）、改进过的Adhoc军用技术以及自组织路由技术。
特点是
1、使用狼群战术。即，单个传感器节点功能弱小 造价低廉，一旦被组织成一个整体则可以被发挥出的巨大功效；
2、强悍的生存力。正因为造价低廉，体积微小（号称smart dust，智能灰），所以传感器可以成千上万地被散播在恶劣的自然环境或战争对抗环境中。同时，它继承了网络的设计思想精髓：生存力，来自无中心节点。千万个具备同等功能的传感器可以互相通信、协调、计算。虽然他们没有动力，不能主动的保护自己。但是他们信奉人多力量大、靠数量取胜。即便是被自然风吹雨打毁坏n多个也无损于功能，也能让试图清除灰尘一样传感器的敌人付出巨大的代价！实际应用的时候，只需要小火箭或飞机到目标上空撒一把‘豆子’就可以咯
3、自组织、自愈合的组织形式。技术的精华其实在于无数节点的组织方法:如何让各个点之间的通信耗时最短、耗能最少；如何在若干个点被做掉之后及时恢复正常功能；
应用领域十分广阔，从野生动物监控，到军事侦察和防御，再到环保……关键字是：监控！
军事应用
这个技术可以同时被应用于进攻和防御条件下侦控敌情的用途。
下面从Wiki粘贴来的原文简介
Wireless sensor network
 
Typical Multihop Wireless Sensor Network Architecture
A wireless sensor network (WSN) consists of spatially distributed autonomous sensors to cooperatively monitor physical or environmental conditions, such as temperature, sound, vibration, pressure, motion or pollutants.[1][2]The development of wireless sensor networks was motivated by militaryapplications such as battlefield surveillance. They are now used inmany industrial and civilian application areas, including industrialprocess monitoring and control, machine health monitoring, environmentand habitat monitoring, healthcare applications, home automation, and traffic control.[1][3]
In addition to one or more sensors, each node in a sensor network is typically equipped with a radio transceiver or other wireless communications device, a small microcontroller, and an energy source, usually a battery. A sensor node might vary in size from that of a shoebox down to the size of a grain of dust,[1]although functioning "motes" of genuine microscopic dimensions have yetto be created. The cost of sensor nodes is similarly variable, rangingfrom hundreds of dollars to a few pennies, depending on the size of thesensor network and the complexity required of individual sensor nodes.[1]Size and cost constraints on sensor nodes result in correspondingconstraints on resources such as energy, memory, computational speedand bandwidth.[1]
A sensor network normally constitutes a wireless ad-hoc network, meaning that each sensor supports a multi-hop routing algorithm (several nodes may forward data packets to the base station).
In computer science and telecommunications, wireless sensor networks are an active research area with numerous workshops and conferences arranged each year.
ApplicationsThe applications for WSNs are varied, typically involving some kindof monitoring, tracking, or controlling. Specific applications includehabitat monitoring, object tracking, nuclear reactor control, firedetection, and traffic monitoring. In a typical application, a WSN isscattered in a region where it is meant to collect data through itssensor nodes.
Area monitoringArea monitoring is a common application of WSNs. In area monitoring,the WSN is deployed over a region where some phenomenon is to bemonitored. For example, a large quantity of sensor nodes could bedeployed over a battlefield to detect enemy intrusion instead of using landmines.[4]When the sensors detect the event being monitored (heat, pressure,sound, light, electro-magnetic field, vibration, etc), the event needsto be reported to one of the base stations, which can take appropriateaction (e.g., send a message on the internet or to a satellite).Depending on the exact application, different objective functions willrequire different data-propagation strategies, depending on things suchas need for real-time response, redundancy of the data (which can be tackled via data aggregation and information fusion[5] techniques), need for security, etc.
[edit] Environmental monitoringA number of WSNs have been deployed for environmental monitoring[6].Many of these have been short lived, often due to the prototype natureof the projects. Examples of longer-lived deployments are monitoringthe state of permafrost in the Swiss Alps: The PermaSense Project, PermaSense Live Data Browser and glacier monitoring.
Industrial Monitoring Water/Wastewater MonitoringThere are many opportunities for using wireless sensor networkswithin the water/wastewater industries. Facilities not wired for poweror data transmission can be monitored using industrial wireless I/Odevices and sensors powered using solar panels or battery packs. Aspart of the American Recovery and Reinvestment Act (ARRA), funding is available for some water and wastewater projects in most states.
[edit] Landfill Ground Well Level Monitoring and Pump CounterWireless sensor networks can be used to measure and monitor thewater levels within all ground wells in the landfill site and monitorleachate accumulation and removal. A wireless device and submersiblepressure transmitter monitors the leachate level. The sensorinformation is wirelessly transmitted to a central data logging systemto store the level data, perform calculations, or notify personnel whena service vehicle is needed at a specific well.
It is typical for leachate removal pumps to be installed with atotalizing counter mounted at the top of the well to monitor the pumpcycles and to calculate the total volume of leachate removed from thewell. For most current installations, this counter is read manually.Instead of manually collecting the pump count data, wireless devicescan send data from the pumps back to a central control location to savetime and eliminate errors. The control system uses this countinformation to determine when the pump is in operation, to calculateleachate extraction volume, and to schedule maintenance on the pump.[7]
[edit] Flare Stack MonitoringLandfill managers need to accurately monitor methane gas production,removal, venting, and burning. Knowledge of both methane flow andtemperature at the flare stack can define when methane is released intothe environment instead of combusted. To accurately determine methaneproduction levels and flow, a pressure transducer can detect bothpressure and vacuum present within the methane production system.
Thermocouples connected to wireless I/O devices create the wirelesssensor network that detects the heat of an active flame, verifying thatmethane is burning. Logically, if the meter is indicating a methaneflow and the temperature at the flare stack is high, then the methaneis burning correctly. If the meter indicates methane flow and thetemperature is low, methane is releasing into the environment.[7]
[edit] Water Tower Level MonitoringWater towersare used to add water and create water pressure to small communities orneighborhoods during peak use times to ensure water pressure isavailable to all users. Maintaining the water levels in these towers isimportant and requires constant monitoring and control. A wirelesssensor network that includes submersible pressure sensors and floatswitches monitors the water levels in the tower and wirelesslytransmits this data back to a control location. When tower water levelsfall, pumps to move more water from the reservoir to the tower areturned on.[7]
[edit] Vehicle DetectionWireless sensor networks can use a range of sensors to detect the presence of vehicles ranging from motorcycles to train cars.
[edit] AgricultureUsing wireless sensor networks within the agricultural industry isincreasingly common. Gravity fed water systems can be monitored usingpressure transmitters to monitor water tank levels, pumps can becontrolled using wireless I/O devices, and water use can be measuredand wirelessly transmitted back to a central control center forbilling. Irrigation automation enables more efficient water use andreduces waste.
[edit] Windrow CompostingComposting is the aerobic decomposition of biodegradable organicmatter to produce compost, a nutrient-rich mulch of organic soilproduced using food, wood, manure, and/or other organic material. Oneof the primary methods of composting involves using windrows.
To ensure efficient and effective composting, the temperatures ofthe windrows must be measured and logged constantly. With accuratetemperature measurements, facility managers can determine the optimumtime to turn the windrows for quicker compost production. Manuallycollecting data is time consuming, cannot be done continually, and mayexpose the person collecting the data to harmful pathogens.Automatically collecting the data and wirelessly transmitting the databack to a centralized location allows composting temperatures to becontinually recorded and logged, improving efficiency, reducing thetime needed to complete a composting cycle, and minimizing humanexposure and potential risk.
An industrial wireless I/O device mounted on a stake with twothermocouples, each at different depths, can automatically monitor thetemperature at two depths within a compost windrow or stack.Temperature sensor readings are wirelessly transmitted back to thegateway or host system for data collection, analysis, and logging.Because the temperatures are measured and recorded continuously, thecomposting rows can be turned as soon as the temperature reaches theideal point. Continuously monitoring the temperature may also providean early warning to potential fire hazards by notifying personnel whentemperatures exceed recommended ranges.[7]
[edit] Greenhouse MonitoringWireless sensor networks are also used to control the temperature and humidity levels inside commercial greenhouses.When the temperature and humidity drops below specific levels, thegreenhouse manager must be notified via e-mail or cell phone textmessage, or host systems can trigger misting systems, open vents, turnon fans, or control a wide variety of system responses. Because somewireless sensor networks are easy to install, they are also easy tomove as the needs of the application change.[7]
[ Edited by jin-1234 on 2010-1-14 15:25 ] |
|
狗仔卡
离线
提升卡
置顶卡
变色卡
