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opportunities and technical development in wireless sensor network

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					International Conference on Computing and Control Engineering (ICCCE 2012), 12 & 13 April, 2012

     OPPORTUNITIES AND TECHNICAL DEVELOPMENT
                         IN
            WIRELESS SENSOR NETWORKS

                             Ms. K. VIJAYALAKSHMI , Assistant Professor
                                 Department Of Computer Applications
                                      Ethiraj College For Women
                             Egmore, Chennai – 600 008 , Tamilnadu, India.
                                      Email id : lkviji@gmail.com

   Abstract

   Wireless Sensor Networks (WSN). These are small embedded sensing platforms with computing
   and communication capabilities, which combine low cost, flexible and fast deployment, resilient
   self management and embedded intelligence for cooperatively delivered value added
   services.WSNis nothing but combining sensors, radios, and CPU’s into an effective wireless
   sensor network requires a detailed understanding of the both capabilities and limitations of each
   of the underlying hardware components, as well as a detailed understanding of modern
   networking technologies and distributed systems theory.

   Keywords
   Wireless sensor networks; sensors; environmental factors; intelligent sensors; monitoring;
   intelligent networks; technology; development; mobiles as sensors.


       1. Introduction
           Sensor networks are composed of a large number of sensingdevices, which are equipped
   with limited computing and radiocommunication capabilities, a wireless sensor node (or simply
   sensor node) consists of sensing, computing, communication, actuation, and power components.
   Thesecomponents are integrated on a single or multiple boards, and packaged ina few cubic
   inches.Due to advances in wireless communications and electronics over the last few years, the
   development of networks of low-cost, low-power, multifunctional sensors has received
   increasing attention. These sensors are small in size and able to sense, process data, and
   communicate with each other, typically over an RF (radio frequency) channel. Wireless Sensor
   Networks are new type of networked systems characterized by                   severely constrained
   computational and energy resources. These networks will consist of hundreds or thousands of
   self-organizing, low power, low cost wireless nodes. Sensor networks often have one or more
   points of centralized control called base stations. A base station (sink) is typically a gateway to
   another network, a powerful data processing or storage center, or an access point for human
   interface which are used as a nexus to disseminate control information into the network or
   extract data from it. They have enough battery power to surpass the lifetime of all sensor nodes,
   sufficient memory to store cryptographic keys, stronger processors, and means for
   communicating with outside networks. The sensor nodes establish a routing forest, with a base
   station at the root of every tree. Base stations are many orders of magnitude more powerful than
   sensor nodes.Real world sensing is undergoing a revolution. Advances in computing platform
   miniaturization, low-power radio and autonomic networking have enabled networked sensor
   systems that are more easily deployed and cost effective than ever before.

                          ISBN 978-1-4675-2248-9 © 2012 Published by Coimbatore Institute of Information Technology
International Conference on Computing and Control Engineering (ICCCE 2012), 12 & 13 April, 2012

       2. Applications
      The applications for WSNs are many and varied. They are used in commercial and industrial
    applications to monitor data that would be difficult or expensive to monitor using wired sensors.




                                         Figure 1: WSN Application Areas

    Some of the typical applications are:
         Environmental monitoring
         Habitat monitoring
         Acoustic detection
         Seismic Detection
         Military surveillance
         Inventory tracking
         Medical monitoring
         Process Monitoring




                                  Figure 2 : Wireless Sensor Network Module

   A WSN system is ideal for an application like environmental monitoring in which the
   requirements mandate a long-term deployed solution to acquire water, soil, or climate
   measurements. For utilities such as the electricity grid, streetlights, and water municipals,

                          ISBN 978-1-4675-2248-9 © 2012 Published by Coimbatore Institute of Information Technology
International Conference on Computing and Control Engineering (ICCCE 2012), 12 & 13 April, 2012
   wireless sensors offer a lower-cost method for collecting system health data to reduce energy
   usage and better manage resources. In structural health monitoring, you can use wireless sensors
   to effectively monitor highways, bridges, and tunnels. You also can deploy these systems to
   continually monitor office buildings, hospitals, airports, factories, power plants, or production
   facilities.




   Figure 3 : Environmental, ground water, cathodicprotection, dams, docks, depots, stations,
   areas, trucks, valves, humidity & temperature etc.

   A Wireless Sensor Network is a self-configuringnetwork of small sensor nodes communicating
   among themselves using radio signals, anddeployed in quantity to sense, monitor andunderstand
   the physical world.Wireless Sensor nodes are called motes. WSN provide a bridge between the
   real physicaland virtual worlds.Allow the ability to observe the previouslyunobservable at a fine
   resolution over large spatiotemporalscales.Have a wide range of potential applications
   toindustry, science, transportation, civil infrastructure,and security.


       2.1.         WSN application examples
   1.Disaster relief operations
          Drop sensor nodes from an aircraft over a wildfire
          Each node measures temperature
          Derive a “temperature map”




                          ISBN 978-1-4675-2248-9 © 2012 Published by Coimbatore Institute of Information Technology
International Conference on Computing and Control Engineering (ICCCE 2012), 12 & 13 April, 2012
   2. Biodiversity mapping
          Use sensor nodes to observe wildlife




   3. Intelligent buildings (or bridges)
           Reduce energy wastage by proper humidity, ventilation, air conditioning (HVAC) control
           Needs measurements about room occupancy, temperature, air flow, …
           Monitor mechanical stress after earthquakes




   4. Machine surveillance and preventive maintenance
         Embed sensing/control functions into places no cable has gone before
         E.g., tire pressure monitoring.




   5. Precision agriculture
          Bring out fertilizer/pesticides/irrigation only where needed
   6. Medicine and health care
          Post-operative or intensive care
          Long-term surveillance of chronically ill patients or theelderly



       3. WSN System Architecture
   In a common WSN architecture, the measurement nodes are deployed to acquire measurements
   such as temperature, voltage, or even dissolved oxygen. The nodes are part of a wireless network
   administered by the gateway, which governs network aspects such as client authentication and
   data security. The gateway collects the measurement data from each node and sends it over a
   wired connection, typically Ethernet, to a host controller.




                          ISBN 978-1-4675-2248-9 © 2012 Published by Coimbatore Institute of Information Technology
International Conference on Computing and Control Engineering (ICCCE 2012), 12 & 13 April, 2012




                         Figure 5: Common Wireless Sensor Network Architecture

       4. Technology Development
   WSNs form a particular class of ad hoc networks that operatewith little or no infrastructure.
   WSNs are gaining momentumas they have great potential for both research and commercial
   applications. The sensor network nodes themselves are ideallyof application specific sensors, a
   wireless transceiver, asimple general purpose processor, possibly assisted by limited amount of
   special-purpose hardware, and an energy unit thatmay be a battery or a mechanism to obtain
   energy from theenvironment. We cannot assume that sensor nodes will be tamper- resistant,
   although we will consider the availability of suchtamper-resistant nodes for future applications.
   Sensor nodesare distributed over a potentially vast geographical area toform a static, multi-hop,
   self-organizing network. However,also mobile WSNs and mobility within WSN are conceivable




               Figure 6: Wireless Sensor Network architecture - Mote: a particle of dust”,




                          ISBN 978-1-4675-2248-9 © 2012 Published by Coimbatore Institute of Information Technology
International Conference on Computing and Control Engineering (ICCCE 2012), 12 & 13 April, 2012

       4.1.         Technology building blocks
   WSNs are self-organizing networks of small embedded devices called motes4 as shown in
   Figure 6. These are deployed in the environment being monitored, either placed individually or
   scattered with high enough density relative to their sensing and communication ranges to ensure
   good connectivity and sensing coverage.

   The self-organization algorithms and protocols in the motes ensure that the devices form a
   network and carry out their monitoring tasks. These include sensing activities, but may also
   involve determining their location, exchanging sensing information, aggregating data, reasoning
   in a local or distributed manner, raising alarms, activating other sensors, etc. As the devices are
   generally constrained in terms of communication bandwidth, processing power and energy
   supply, optimal use of the resources is an important factor in designing the monitoring tasks. In
   order to communicate with the outside world, WSNs rely on gateways. These may be fixed or
   mobile, permanently or intermittently present, unique or multiple. They allow access to the
   monitoring services from a corporate network or the wider Internet. As a higher capability and
   availability platform, the gateway can also host management, processing and security functions
   for the WSN.




                                        Figure 7 : Sensor node architecture


       4.2.         How Wireless Sensor Networks Work
   Wireless Sensor Network mechanism is quite simple and applicable to a variety of fields. It is
   based on Smaller nodes, controller, radio transceiver, and battery. The key to stimulate the sensor
   networking is the algorithm sponsor multi-router phenomenon. The system is totally dependent
   on the nodes and the harmony established between them through proper frequency. These nodes
   are of different sizes according to the function they perform. To activate the monitoring /
   tracking function of these nodes a radio transmitter is attached to forward the information in the
   form of waves. They are controlled by the microcontroller according to the function and device
   in which they are used. All the system remains in working condition with the help of energy
   supply which is in the form of battery. The wireless sensor networks perform function
   concurrently where nodes are autonomous bodies incorporated in the field spatially for the
   accurate results. The information transmits through proper channel taking the information
   collecting it in the form of data and send to the base.



                          ISBN 978-1-4675-2248-9 © 2012 Published by Coimbatore Institute of Information Technology
International Conference on Computing and Control Engineering (ICCCE 2012), 12 & 13 April, 2012
       4.3.          The Electromagnetic Spectrum
   The Electromagnetic Spectrum can be used to fabricate Remote Sensors of a wide variety of
   types. Generally the wavelength suitable for a particular application is selected based on the
   propagation distance, the level of detail and resolution required, the ability to penetrate solid
   materials or certain mediums, and the signal processing difficulty. Doppler techniques allow the
   measurement of velocities. Millimeter waves have been used for satellite remote monitoring.
   Infrared is used for night vision and sensing heat. IR motion detectors are inexpensive and
   reliable. Electromagnetic waves can be used to determine distance using time-of-flight
   information- Radar uses RF waves and Lidar uses light (laser). The velocity of light is c=
              6
   299.8x10 m/s. GPS uses RF for absolute position localization. Visible light imaging using
   cameras is used in a broad range of applications but generally requires the use of sophisticated
   and computationally expensive DSP techniques including edge detection, thresholding,
   segmentation, pattern recognition, motion analysis, etc.




       5. Advantages & Development of Wireless Sensors
       5.1.          Advantages :
                  Much cheaper to deploy than wired sensors
                  Sensor nodes can be added or removed easily
                  Node location can be changed without rewiring
                  Can be configured into different network topologies
                     - Star, Mesh, etc.

       5.2.          Development :




           Figure 9: mobiles as sensors – a forecast
                           ISBN 978-1-4675-2248-9 © 2012 Published by Coimbatore Institute of Information Technology
International Conference on Computing and Control Engineering (ICCCE 2012), 12 & 13 April, 2012



       6. Conclusion
   This Paper presents an overview of the opportunities and technical development in Wireless
   Sensor Networks. This paper describes briefly howall of this sensor network research is
   producing a new technology. The future should see an accelerated pace of adoption of this
   technology.It’s an interesting, complex, new technologyand lots of research still to be done.The
   paper concludes on a note of quoting the inevitable role played by Wireless Sensor Networks and
   its applications.


       7. References
           1. Wireless Sensor Networks: An Information Processing Approach (The Morgan
               Kaufmann Series in Networking)Leonidas Guibas.
           2. Fundamentals of Wireless Sensor Networks: Theory and Practice (Wireless
               Communications and Mobile Computing)by Waltenegus Dargie.
           3. Wireless Sensor Networks by Ian F. Akyildiz, Mehmet Can Vuran.
           4. Agrawal, Dharma P.; Qing-An Zeng. 2003. Introduction to Wireless and Mobile
               Systems. Brooks/Cole – Thompson, Pacific Grove, CA.
           5. Wireless sensor networks: a networking perspective by Jun Zheng (Ph. D.), Jun
               Zheng, Abbas Jamalipour.
           6. Guide to Wireless Sensor Networks by Sudip Misra, Subhas Chandra Misra, Isaac.
           7. Wireless Sensor Networks: Technology, Protocols, and Applications Kazem Sohraby,
               Daniel Minoli, Taieb Znati.
           8. Kazem Sohraby, Daniel Minoli, Taieb Znati., “Wireless Sensor Networks:
               Technology,Protocols, and Applications”, Wiley Student Edition
           9. Feng Zhao & Leonidas Guibas, “Wireless Sensor Networks, An Information
               ProcessingApproach”, Morgan Kaufmann
           10. Jun Zheng, Abbas Jamalipour, “Wireless Sensor Networks: A Networking
               Perspective”,Wiley
           11. Ian F. Akyildiz, Mehmet Can Vuran, “Wireless Sensor Networks”, Wiley
           12. Waltenegus Dargie, Christian Poellabauer, “Fundamentals of Wireless Sensor
               Networks:Theory and Practice”, Wiley




                          ISBN 978-1-4675-2248-9 © 2012 Published by Coimbatore Institute of Information Technology

				
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