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Wireless sensor networks2



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  • 1. MANAGING DISASTER WITH WIRELESS SENSOR NETWORKS INTRODUCTION A wireless sensor network (WSN) is a group of low cost ,low power,multifunctional and small size wireless sensor nodes that cooperate togetherto sense the environment, process the data and communicate wirelesslyover a short distance . The sensors are commonly used to monitor physicalor environmental conditions, such as temperature, sound, vibration,pressure, motion or pollutants, at areas of interest. Some of these sensornodes are able to move on their own, this is achieved by mounting thesensors on mobile platforms. The development of WSN was originally motivated by militaryapplication such as battlefield surveillance. However, WSN are now used inmany industrial and civilian application areas, including industrial processmonitoring and control, machine health monitoring, environment andhabitat monitoring, disaster management, healthcare applications, homeautomation and traffic control. In this paper we will review the applicabilityof WSN in improving and assisting disaster management operations.. WSN has many possible applications that have not yet beenexplored. WSN is a fast growing technology however much written aboutWSN is still theory. ’How to deploy WSNs,’ although having much theorywritten still currently lacks practical guide. Using our research experienceand the practical real life solutions found when deploying a WSN for theapplications this outlines the steps required when conducting a real worlddeployment of a WSN .In the application for WSN most focused on is forpurpose of detecting natural disasters. WSN can be useful to disastermanagement in two ways. Firstly, WSN has enabled a more convenientMUSALIAR COLLEGE OF ENGINEERING AND TECHNOLOGY 1
  • 2. MANAGING DISASTER WITH WIRELESS SENSOR NETWORKSearly warning system and secondly, WSN provides a system able to learnabout the phenomena of natural disasters. Natural disasters are increasing worldwide due to the globalwarming and climate change .The losses due to these disasters areincreasing in an alarming rate. Hence, it is would be beneficial to detect thepre-cursors of these disasters, early warn the population, evacuate them,and save their life. However, these disasters are largely unpredictable andoccur within very short spans of time. Therefore technology has to bedeveloped to capture relevant signals with minimum monitoring delay.Wireless Sensors are one of the cutting edge technologies that can quicklyrespond to rapid changes of data and send the sensed data to a data analysiscenter in areas where cabling is inappropriate.WSN technology has thecapability of quick capturing, processing, and transmission of critical datain real-time with high resolution. However, it has its own limitations suchas relatively low amounts of battery power and low memory availabilitycompared to many existing technologies .It does, though, have theadvantage of deploying sensors in hostile environments with a bareminimum of maintenance. This fulfills a very important need for any realtime monitoring, especially in hazardous or remote scenarios.MUSALIAR COLLEGE OF ENGINEERING AND TECHNOLOGY 2
  • 3. MANAGING DISASTER WITH WIRELESS SENSOR NETWORKS EXISTING SYSTEM SATELLITE MONITORING Satellites specifically designed to observe Earth from orbit, similarto reconnaissance satellites but intended for non-military uses such asenvironmental monitoring, meteorology, map making etc. Most Earthobservation satellites carry instruments that should be operated at arelatively low altitude There are two main disadvantages of satellite communication. Thefirst is cost. Developing, launching and maintaining a satellite is extremelyexpensive. No further explanation of that is necessary. The second is thetime delay in responding. Communications satellites are typicallypositioned so they rotate around the earth at the same rotation rate as theearth. This is called geosynchronous positioning. The geosynchronousorbit is far from earth, so the time it takes for the signal to reach the satelliteand then bounce back to earth is about half a second. The delays can bevery annoying on voice calls, as people tend to talk over each other. Thedelays are also problem with data exchange, as data response packets arealso delayed which limits the effective bandwidth of the channel. One waybroadcasts, like TV and Radio signals are perfect for satellites as noresponse is required.MUSALIAR COLLEGE OF ENGINEERING AND TECHNOLOGY 3
  • 4. MANAGING DISASTER WITH WIRELESS SENSOR NETWORKS PROPOSED SYSTEM A wireless sensor network (WSN) is a group of low cost, low power,multifunctional and small size wireless sensor nodes that cooperate togetherto sense the environment, process the data and communicate wirelesslyover a shortdistance . The sensors are commonly used to monitor physical orenvironmental conditions, such as temperature, sound, vibration, pressure,motion or pollutants, at areas of interest. Some of these sensor nodes areable to move on their own, this is achieved by mounting the sensors onmobile platforms. The development of WSN was originally motivated by militaryapplication such as battlefield surveillance. However, WSN are now used inmany industrial and civilian application areas, including industrial processmonitoring and control, machine health monitoring, environment andhabitat monitoring, disaster management, healthcare applications, homeautomation and traffic control . In this paper we will review theapplicability of WSN in improving and assisting disaster managementoperations. I.NEED FOR DISASTER MANAGEMENT Studies over the recent years have gathered evidences indicating thatthe global climate is changing. The changes include the occurrence ofextreme climate phenomenon that may have disastrous consequences to ushuman. The Intergovernmental Panel on Climate Change (IPCC) identifieda number of extreme climate phenomenon with high level of likelihood tooccur ;MUSALIAR COLLEGE OF ENGINEERING AND TECHNOLOGY 4
  • 5. MANAGING DISASTER WITH WIRELESS SENSOR NETWORKSi. Heat Wavesii. Floodsiii. Landslidesiv. Avalanchev. Soil Erosionvi. Tropical Cyclonesvii. Droughtviii. Storms. The effects of the global climate change are clearly felt by manyaround the globe. The extreme climates together with uncontrollable humanactivities increase the frequencies of disastrous events which affect highernumbers of people with increasing levels of life threatening damages. Thusthere is the need for more comprehensive regional and local risk reductionstrategies. Thus, it is important for authorities to ensure their risk reductionstrategies include effective prediction, detection, monitoring, alerting, and,search and rescue systems. The National Security Council (NSC) had laidout its total disaster risk management strategy into four parts;i. prevention and mitigation,ii. Preparedness – prediction and early warning system, awarenessiii. Response – search and rescue, relief, medicaliv. Recovery – analysis, rehabilitation, reconstruction. The first two parts of the strategy are to be implemented before adisaster occurs while the other two are implemented after a disasterhappens. An efficient disaster prediction, monitoring and alerting systemcould help the authorities and public to be better prepared to face anincoming disaster thus reducing the lost of life and properties risks. AnotherMUSALIAR COLLEGE OF ENGINEERING AND TECHNOLOGY 5
  • 6. MANAGING DISASTER WITH WIRELESS SENSOR NETWORKScrucial aspect for reducing the amount of casualties is the search and rescueoperation. We believe that WSN can play an important role in enhancingthese two aspects of disaster management. A number of studies had shownthe applicability of WSN for functions suitable for these kinds of systems. A WSN used for disaster detection and alerting system could sensefor any significant changes in the environment and send an appropriate alertsignal, for example sensors sensing water level at a river bank and tiltmeters at a hill side could alert the authorities and public for possible floodand landslide. In search and rescue application the deployed WSNs can thedisaster area and locate the victims via the numerous sensing modes. TheWSN can then provide the search and rescue teams with the identifiedlocations of the victims needing rescue. The WSN can also provide theteams with crucial information such as the surrounding of the disaster site,obstacles that they need to overcome and avoid, etc. Thus, the search andrescue teams will be able to plan their operation with higher level ofprecision, timeliness and safety for both the victims and their members. II. DESIGN ISSUES There are multiple issues to be considered when designing WSN fordisaster management. The first thing to be identified is the type of disasterto be handled .Different situation called for different system design, forexample air quality monitoring requirement is not the same as search andrescue operation.Among the design issues are:A) DeploymentMUSALIAR COLLEGE OF ENGINEERING AND TECHNOLOGY 6
  • 7. MANAGING DISASTER WITH WIRELESS SENSOR NETWORKS Deployment is regarding on how the network is being installed.WSN is typically deployed in two methods predeterministic or randomly.In predeterministic deployment the location of the sensors is decided firstbefore the sensor nodes are deployed. In this method other issues like thedegree of coverage and nodes connectivity are guaranteed. Randomdeployment is simpler than the predeterministic deployment where thesensor nodes are randomly scattered in the region of interest. It allows theWSN to be deployed over hostile and unreachable environment, forexample the nodes can be dispersed from an unmanned air vehicle (UAV)over a remote area for forest fire detection.B) Coverage In three types of coverage are discussed; blanket coverage, barriercoverage and sweep coverage. This classification is borrowed from roboticsystem. Blanket coverage aims to provide maximum detection rate in aregion of interest whereas for barrier coverage instead of providingcoverage throughout the region of interest the focus is now on ensuring thatthe perimeter of the region of interest is fully covered. Both blanket andbarrier coverage can be achieve through static arrangement of the sensor.For sweep coverage the objective is achieved by moving the sensor nodesso that the region of interest is swept by the sensors sensing range. Thereare other specifications of coverage, such as listed in; area coverage, barriercoverage and point coverage. Area coverage is on how to cover an areawith the sensors, where the objective is to maximize the coveragepercentage. Coverage percentage is ratio of area covered by at least onesensor to the total area of the region of interest. Coverage problem can alsobe seen as a minimization problem .From the minimization point of view,MUSALIAR COLLEGE OF ENGINEERING AND TECHNOLOGY 7
  • 8. MANAGING DISASTER WITH WIRELESS SENSOR NETWORKSthe objective is to make sure the total area of the coverage holes in thenetwork is as small as possible. Area coverage is similar to blanketcoverage. Point coverage is coverage for a set of points of interest.Basically this type of coverage is concern only on how to cover a set oftargets or hotspots in an area, instead of the whole area as in area coverage.Area, blanket and sweep coverage are suitable for disaster managementapplications. A disaster prone area can be thoroughly monitor using blanketcoverage whereas sweep coverage can be used for a more active sensing.C) Connectivity Each sensor node in a WSN senses for occurrences of event ofinterest, this information need to be relayed to the base station. Thereforeconnectivity of the sensors to their base station and also connectivityamong themselves is another important issue to be considered. Typically inWSN, information is relayed to a base station using multi hopcommunication, where the information is transmitted from a node toanother node until the information reaches the base station. However thisapproach needs a connected network where at least a spanning tree exists toconnect the nodes to their base station. The problem with this kind ofnetwork is that information would be lost if a link is broken, in addition tothat in some environments obstacle such as a very dense rainforest or otherobstruction will make it difficult to maintain connectivity. In a movingbase station is proposed. The mobile base station collects information bymoving across the monitored area.D) Mobility Sensor mobility is another aspect to be considered in designing aWSN system. Mobility can be classified into two type; uncontrolled andcontrolled mobility. For uncontrolled mobility the movement is eitherMUSALIAR COLLEGE OF ENGINEERING AND TECHNOLOGY 8
  • 9. MANAGING DISASTER WITH WIRELESS SENSOR NETWORKScaused by environmental influences such as wind and wave or the mobilityis due to the sensor is embedded to a moving subject. In controlled mobilitythe sensor nodes are able to determined where and when to movethemselves. Controlled mobility is an attractive feature as it allows thesensors to self maintain the network, to harvest energy, to collectinformation using mobile based stations and to compensate for lack ofsensors in providing enough coverage by constantly moving the sensors sothat the chance of target detection is improved . It could also help to allowthe WSN to provide sweep coverage thus minimizing number of misseddetection . On the other hand mobility usually will cause the sensor node tobe bigger and bulkier thus limiting the movement of sensors in narrow orsmall spaces.E) Type of sensors The last issue to be considered here is the type of sensors to be usedon the sensor nodes. Among the sensors used for disaster management are;motion detector sensor – sensing any sign of movement, camera – to obtainvisual information, tilt meter – for landslide monitoring, humidity sensor,temperature sensor, ultrasonic sensors – for water measurement and etc.Which type of sensors to be chosen is based on the targeted types ofdisasters. III.REQUIREMENT ANALYSIS This section will describe in detail how to design a real-timeWireless Sensor Network (WSN), and what are theconsiderations/requirements that have to be analyzed for designing thenetwork for any scenario. The different processes that will contribute to aWSN design are:MUSALIAR COLLEGE OF ENGINEERING AND TECHNOLOGY 9
  • 10. MANAGING DISASTER WITH WIRELESS SENSOR NETWORKS• Analysis of Scenario Wireless Sensor Networks (WSN) could be useful in a vast anddiverse amount of applications. The chosen target scenario must beunderstood and investigated thoroughly in order to choose the mostappropriate sensors and network. A comprehensive analysis of the scenariois one of the first steps to undertake when considering the design of thesystem. The constraints found (from the analysis of the scenario) determineand govern the overall size and type of network and sensors required.Understanding the characteristics of a scenario allows logical links to bemade about how to detect the occurrence of land movement.• Selection of Geophysical Sensors The key geophysical sensors such as rain gauge, soil moisturesensors, pore pressure transducers, strain gauges, tilt meters, and geophonesare identified for measuring the principal parameters. These sensors areselected based on their relevance in finding the causative geological factorsfor disaster. The details of the selected sensors are:• Placement of Geophysical Sensors All the chosen geophysical sensors are capable of real-timemonitoring with bare minimum maintenance. A DEP(Deep Earth Probe)was devised to deploy these many sensors as a stack, attached to a verticalpipe, in different locations of the landslide prone site. This generalizeddesign for the DEP, and the sensor placement procedures at the DEP hasbeen developed and implemented to simplify future deployments. Thisdesign can be adapted for any landslide prone area and potentially forMUSALIAR COLLEGE OF ENGINEERING AND TECHNOLOGY 10
  • 11. MANAGING DISASTER WITH WIRELESS SENSOR NETWORKSplacing sensors to detect other natural disasters, in other disaster proneareas.• Wireless Sensor Network Requirements Disaster detection requires wide area monitoring, and real-time,continuous data collection, processing, and aggregation. Wireless SensorNetworks (WSNs) are the key emerging technology that has the capabilityto real-time, continuous data collection, processing, aggregation withminimum maintenance. Any wide area monitoring must determine the:– Maximum number of wireless sensor nodes,– Maximum number of relay nodes,– Maximum frequency of data collection from each node per minute,– Maximum data rate required,– Maximum power required for sampling, transmitting, processing, andreceiving,– Maximum tolerance limit of delay,– Maximum tolerance limit of data packet loss.• Algorithm Requirements Wide area monitoring requires efficient algorithm development fordata collection, processing, and transmission. The different criteria to beanalyzed for designing the algorithms are: the total area of deployment,maximum and minimum transmission range, maximum number of sensornodes necessary, maximum number of sensor nodes available, maximumamount of power available (in the battery), the corresponding transmissionrange, data storage capability of each node, availability of constant powersource, maximum bandwidth availability, frequency of data collection andMUSALIAR COLLEGE OF ENGINEERING AND TECHNOLOGY 11
  • 12. MANAGING DISASTER WITH WIRELESS SENSOR NETWORKStransmission specific to the application scenario, and the data aggregationmethod suitable for the applicationunder consideration. Analysis of the above requirements contributes to thedevelopment of required algorithms for designing the network topology,data collection algorithm, data aggregation algorithm, data disseminationmethod, energy optimized network, networks with maximum life time, timesynchronized network, localization techniques etc.• Network Requirements The design and development of the complete network architecturerequires the knowledge and understanding of relevant technologies such aswireless networks, wired networks, cellular networks, satellite networksetc., maximum number of nodes, maximum data rate, available bandwidth,traffic rate, delay, distance between the point of data initiation and itsdestination, data transmission, delay, and data packet loss,accessibility/connectivity of the area, transmission range, identification ofthe communication protocol and radio interface technology, integration ofthe application specific algorithms for data collection and aggregation,routing and fault tolerance etc. These requirements have to be thoroughlyanalyzed with regard to the conditions of the deployment area, maximumdata transmission distance, traffic rate, and the available technologies.Choose the best technologies that can be integrated effectively to achieveminimum data packet loss, delay, minimum power consumption, and fastarrival of data.• Data Analysis RequirementsMUSALIAR COLLEGE OF ENGINEERING AND TECHNOLOGY 12
  • 13. MANAGING DISASTER WITH WIRELESS SENSOR NETWORKS The data received from the deployment area has to be modeled andanalyzed according the application scenario requirements. Statisticalmodels and pattern recognition techniques can be used for further dataanalysis to determine the warning levels. Warning levels are the level ofindication (from the sensors) that a disaster maybe becoming possible orabout to occur. Along with this data analysis architecture has to bedeveloped for effective and fast data analysis.• Data Visualization Requirements The development of real-time systems requires the design anddevelopment of: a data dissemination method, a channel or technology thatcan be used for data dissemination (within the shortest amount of time), andthe data visualization criteria & methods specific to the applicationscenario. The method of data dissemination, and the allowable delay fordata dissemination, and the techniques that should be adopted for datadissemination will depend on the application scenario under consideration.The architecture for data visualization has to be developed with the goal ofeffective and fast streaming of data. IV.WIRELESS SENSOR NETWORK ARCHITECTURE The current deployment used a placement strategy using the HybridApproach, by in corporating both the Matrix Approach and theVulnerability Index Approach. The whole deployment area was initiallysectored using Matrix Approach. In each cell, the deployment location ofthe Wireless Probe (WP) is decided after considering the VulnerabilityIndex Approach .This has helped to maximize the collection of relevantinformation from the landslide prone area.MUSALIAR COLLEGE OF ENGINEERING AND TECHNOLOGY 13
  • 14. MANAGING DISASTER WITH WIRELESS SENSOR NETWORKS The wide area monitoring using Wireless Sensor Network (WSN) isachieved using a regionalized two-layer hierarchical architecture. Since thegeological and hydrological properties of each of the locations, of the area,differ with respect to the different regions they belong to they are dividedinto regions. The data received from each of the sensors cannot beaggregated together due to the variability in soil geological andhydrological properties .So the whole area is divided into regionspossessing soil geological and hydrological properties unique to theirregion. In this particular case, the deployment area is divided into threeregions such as crown region, middle region, and to region of the slope andnumerous WPs is deployed in these regions. V. WIRELESS NETWORK DESIGN AND ARCHITECTURE One of the important requirements for any landslide detectionsystem is the efficient delivery of data in near real-time. This requiresseamless connectivity with minimum delay in the network. The wirelesssensor network follows a two-layer hierarchy, with lower layer wirelesssensor nodes, sample and collect the heterogeneous data from the DEP(Deep Earth Probe) and the data packets are transmitted to the upper layer.The upper layer aggregates the data and forwards it to the sink node(gateway) kept at the deployment site .The current network has 20 wirelesssensor nodes spread on two different hardware platforms. The firsthardware platform is Crossbow MicaZ. This MicaZ network follows a two-layer hierarchy, with a lower level (wireless probes) and a higher level(cluster head), to reduce the energy consumption in the total network. Thewireless probes (lower level nodes) sample and collect the heterogeneousdata from the DEP (Deep Earth Probe) and the data packets are transmittedto the higher level. The higher level aggregates the data and forwards it toMUSALIAR COLLEGE OF ENGINEERING AND TECHNOLOGY 14
  • 15. MANAGING DISASTER WITH WIRELESS SENSOR NETWORKSthe probe gateway (sink node) kept at the deployment site. The secondhardware platform, used, is the newly developed WINSOC wireless sensornodes .One purpose of this WINSOC network is to extensively test andvalidate the WINSOC nodes, with respect to performance reliability andenergy trade-offs between the two hardware platforms. WINSOC nodes areendowed with a WINSOC distributed consensus algorithm. Anotherpurpose of this network is to test and validate the performance andscalability of the WINSOC distributed consensus algorithm. This networkis scalable as it provides the capability to incorporate any new fieldnetworks to the current network. Data received at the gateway has to be transmitted to the FieldManagement Center (FMC)which is approximately 500m away from thegateway. A Wi-Fi network is used between the gateway and FMC toestablish the connection. The FMC incorporates facilities such as a VSAT(Very Small Aperture Terminal) satellite earth station and a broadbandnetwork for long distant data transmission. The VSAT satellite earth stationis used for data transmission from the field deployment site. The DMCconsists of the database server and an analysis station, which performs dataanalysis and landslide modeling and simulation on the field data todetermine the landslide probability. The real-time data and the results of thedata analysis are real-time streamed on the Internet. Alert services such asE-Mail, SMS and MMS are implemented to alert about: the probability,status of the network and for monitoring the system components. Faulttolerance is achieved even during extreme weather conditions. For example,if the VSAT network becomes unavailable, the WAWN adapts by using thebroadband or GPRS connectivity at the FMC for uploading the real-timedata directly to a web page with minimum delay and thus providing faultMUSALIAR COLLEGE OF ENGINEERING AND TECHNOLOGY 15
  • 16. MANAGING DISASTER WITH WIRELESS SENSOR NETWORKStolerance. The entire system is equipped to remotely monitor the level ofbattery charges and the level of solar charging rate, and indicate faultywireless sensor nodes or geological sensors. A feedback loop is used thatremotely changes, the sampling rate of the geological sensors, with respectto the real-time climatic variations. This proposed network architecture is scalable, as any number ofnodes and deployment fields can be incorporated via a Wi-Fi network to thesame FMC. In future, this provide the capability to monitor many verylarge areas and also to incorporate the different spatio -temporal analysis toprovide an even better understanding of landslides.. The differentdeployment sites can connect to the FMC via a Wi-Fi network. FIG: Wireless sensor network Architecture VI. WIRELESS SENSOR NETWORK ALGORITHMS The wireless sensor network designed and deployed for wide areamonitoring requires efficient data collection, data aggregation, energyMUSALIAR COLLEGE OF ENGINEERING AND TECHNOLOGY 16
  • 17. MANAGING DISASTER WITH WIRELESS SENSOR NETWORKSmanagement, and fault tolerant methods. Regionalized dynamic clusteringmethod is designed and implemented for effective geological andhydrological data collection using the wireless sensor network. Threshold based temporal data collection and data aggregationmethod is designed and implemented for effective data aggregation. Thisalgorithm combined with the newly designed state transition algorithmcontributes optimum energy consumption by each node and in increasingthe life time of the whole network, avoiding unnecessary collection,processing and transmission of redundant data thus achieving increasedenergy efficiency and the simplification of the data analysis & visualizationprocess. Fault tolerant methods are designed and integrated in the wirelesssensor network for effective handling of node failure, reduced signalstrength, high data packet loss, and low balance energy per node. VII. WIRELESS SOFTWARE ARCHITECTURE Real-time monitoring and detection of landslides require seamlessconnectivity together with minimum delay for data transmission. Theexisting Wireless Sensor Network (WSN) system incorporates variousheterogeneous wireless networks such as the WSN, Wi-Fi, satellitenetwork, and broadband network. Each of these networks perform atdifferent frequency range, that contributes to different traffic rate,congestion, data packet loss, buffering methods, delay, and different datacollection, transmission, and processing methods. Hence to reduce thecomplexity in dealing with different types of wireless network, genericsoftware architecture was designed and implemented for achieving all therequirements of each of the wireless network. This wireless softwareMUSALIAR COLLEGE OF ENGINEERING AND TECHNOLOGY 17
  • 18. MANAGING DISASTER WITH WIRELESS SENSOR NETWORKSarchitecture includes wireless sensor network software, wireless sensorgateway software, and a middleware for heterogeneous wireless networks.. VIII. WSN FOR DISASTER MANAGEMENT PROJECTS There are a number of projects conducted for enhancing disastermanagement operations including search and rescue operation with the helpof WSN. WSN is commonly used for monitoring and detection in disasterprone areas. Data collected provide authorities with the abilities to makepredictions which help them with the decisions such a evacuation, issuingwarnings, etc. In search and rescue operations, generally, the WSN is usedto locate victims and help the rescuers to assess the situation from a safedistance thus allowing them to come out with an effective rescue plan. Inthis section we will review some of these projects.A) Early Warning Flood Detection Systems The aim of the project is to predict the incoming flood hours beforeit happens so that the communities have enough time for evacuation. Thesystem proposed, measures the river level, rainfall, soil conditions and airtemperature for the prediction. The readings will be compared with data inlook up table to determine whether the threat exists. The nodes used in thisproject are solar powered and the system communicates in two modes;mini-network for short range communication -within 8km, and long-rangelinks for communication of approximately 25km. The prediction is to beinformed to selected city members whom are responsible for alerting theircommunities of potential danger.B) Low Cost WSN Based Flood and Landslide Monitoring System In a WSN for floods and landslide monitoring system is proposed.The system used ultrasonic sensors to measure water level, luminanceMUSALIAR COLLEGE OF ENGINEERING AND TECHNOLOGY 18
  • 19. MANAGING DISASTER WITH WIRELESS SENSOR NETWORKSsensors, temperature sensors and wireless IP camera for visual monitoring.The nodes communicate using single hop or multi hop. The reading of asensor is send to its aggregator node which aggregates all the readings fromits neighboring sensors before transmitting the aggregated readings to thebase station. Each of the nodes is uniquely identified using the individual IPaddress. The authors believe that this system could be adopted as tsunamiearly warning system too.C) WSN for Debris Flow Observation A WSN for monitoring debris flow in mountainous area in Taiwan isproposed in . The WSN is adopted to provide a better monitoring systemcompared to the traditional method. The wireless communication solvesissues faced by traditional method such as broken telephone line duringsevere weather conditions. This project also proposed mobile sensor knownas Mass Flow Sensor which will move with the debris so that more accurateand detailed readings can be retrieved. The Mass Flow Sensor is packedwithin a weather proof, pyramid shaped capsule. Each of the capsules isequipped with an accelerometer, radio transceiver, circuit board, a GPS andrechargeable battery. The Mass Flow Sensor will move with the flowingdebris and its reading gives the momentum of the flow. This informationcould be used to signal for possible disaster threat.D) WAPMS: WSN Air Pollution Monitoring System WAPMS is a WSN for monitoring air quality project .Among thepollutants monitored by the sensor nodes are; ozone, fine particles, nitrogendioxide, carbon monoxide, sulphur dioxide and total reduced sulphurcompound. The sensor nodes deployed in the region of interest are dividedinto clusters which are decided based on their location. A cluster head is incharge of collecting data from its cluster members, aggregates the data andMUSALIAR COLLEGE OF ENGINEERING AND TECHNOLOGY 19
  • 20. MANAGING DISASTER WITH WIRELESS SENSOR NETWORKStransmit it to the sink. The system used multiple sinks with each sink is incharge of a group of cluster heads. The sinks are connected to a gatewaywhich relays the readings to database. A new data aggregation algorithm; Recursive Converging Quartiles(RCG), was proposed for WAPMS. The PCQ algorithm is divided into twoparts; duplicate elimination and data fusion. In the first part, the algorithmchecks for any duplicated data using packets id. The second part of thealgorithm is to summarize the data.E) WSN for Volcanic Eruption Monitoring Among the earliest application of WSN for volcanoes monitoring isreported in . Infrasonic microphones are used as low-frequency acousticsensors to sense infrasonic signals from erupting volcano. These acousticsensors are connected to aggregator. The aggregator sends its collected datato the base station over a long range wireless link.F) WSN for Flash-Flood Alerting The system is designed to predict, detect and generate alarm. Thereare six categories; i) no sign of flash flood – data from the sensor nodesshows stable readings, ii) rain formation – dropped in air pressure, iii) rain,iv) landslides, v) dam forming – caused by landslide, and vi) flash flood.The sensor nodes used could be grouped into three categories:*Hydrological nodes – to monitor water level and its flow along the riverbank*Meteorological nodes – monitoring light, temperature, humidity,barometric pressure, wind direction and speed of the surrounding.*Landslide nodes – geophone, soil moisture sensor and creep sensor.MUSALIAR COLLEGE OF ENGINEERING AND TECHNOLOGY 20
  • 21. MANAGING DISASTER WITH WIRELESS SENSOR NETWORKSAmong the major challenges for developing flood alerting system is falsealarm, this project focused on the tradeoffs between sensitivity of thesystem and reducing false alarm.G) Search Balls: Special Project for Earthquake Disaster Mitigation In the search balls project, small search balls each equipped withwireless camera, infrared LEDs, radio receiver ,batteries and electroniccircuit are used for searching victims inside collapsed buildings . There aretwo type of search balls; balls with three fixed wireless cameras and ballswith two rotating cameras. The two rotating cameras provide a wider view.All of these equipments are packed in impact resistance ball. The search balls are thrown inside the rubble of a collapse buildingto search for survivors. No controlled mobility is provided to the balls,however due to its structure, the balls will roll and bounce within the rubbleand get scattered around the search area. To compensate for lack ofmobility, large number of balls is deployed. The search balls transmit theirinformation to monitoring station stationed at the perimeter of the rubble.Based on the signal from the balls rescuers are directed towards thevictims’ location thus the rescue mission can be conducted efficiently. Asthe rescuers reach the victims the balls are collected by them to be reused.H) RESRS: Robot Emergency Search and Rescue System RESRS is a project that integrates WSN with the robotic field. TheRESRS system monitors for leakage of hazardous chemicals and conductsearch and rescue operation during emergency events. The system consistsof three parts: WSN of fixed sensor nodes, mobile robots and a monitoringcentre. The mobile robots of RESRS are also equipped with sensorstherefore these robots can also be viewed as WSN of mobile sensor nodes.MUSALIAR COLLEGE OF ENGINEERING AND TECHNOLOGY 21
  • 22. MANAGING DISASTER WITH WIRELESS SENSOR NETWORKS The system operates in two modes; normal mode and rescue mode.In normal mode the fixed WSN monitors the area and record the reading ofthe environment. When a leakage is detected the system switch to rescuemode and the mobile sensor nodes are deployed. The mobile sensor nodesreceive instruction from monitoring centre which makes decision based oninformation from the fixed WSN. These mobile sensors are able to providemore active search and rescue operation. The information from mobilesensors can be used to provide route information to rescuers on how toreach the victims and also to lead the rescuers and victims out to a safesite..MUSALIAR COLLEGE OF ENGINEERING AND TECHNOLOGY 22
  • 23. MANAGING DISASTER WITH WIRELESS SENSOR NETWORKS CONCLUSION Disaster management needs efficient techniques with high level ofprecision and timeliness. WSN is a good candidate for such applications. Inthis paper the need for efficient disaster management application isdiscussed. The design issues of WSN are also reviewed. Existing projectssuch as; WSN for floods monitoring, WSN for landslides monitoring, WSNfor air pollution monitoring, WSN for volcanoes monitoring, search balls,and RESRS are also presented. These projects prove that WSN is aneffective technological solution for a better disaster management, thereforemore research works should be conducted in this area.MUSALIAR COLLEGE OF ENGINEERING AND TECHNOLOGY 23
  • 24. MANAGING DISASTER WITH WIRELESS SENSOR NETWORKS REFERENCES[1] Aini, M.S., Fakhru’l-Razi, A., and Daud, M. “Evoulution ofEmergency Management in Malaysia”,Journal of Contigencies andCrisis Management, Vol. 9, No. 1, 2001.[2] Asian Disaster Reduction Centre (ADRC) “Malaysia CountryReport2008”,, 2008.[3] Basha, E., and Rus, D., “Design of Early Warning FloodDetection Systems for Developing Countries” Proc. of theConference on Information and Communication Technologies andDevelopment, 2007.[4] Batalin, M. A., Sukhatme, G. S. and Hattig, M. “Mobile RobotNavigation using a Sensor Network” IEEE International Conferenceon Robotics and Automation, New Orleans, 2003.[5] Cardei, M. and Wu, J. “Coverage in Wireless Sensor Networks”.In Ilyas, M. and Mahgoub, I. (Eds.), “Handbook of Sensor Networks:Compact Wireless and Wired Sensing Systems”, United States ofAmerica, CRC Press, 2005, pp. 19-1 – 19-12.[6] Castillo-Effen, M., Quitela, D.H., Jordan, R., Westhoff, W., andMoreno, W., “Wireless Sensor Networks for Flash-Flood Alerting”,Proc. of the 5th IEEE International Caracas Conference on Devices,Circuits and Systems, Nov. 2004, pp. 142-146.[7] Chou, P.H., Chung, Y.C., King, C.T., Tsai, M.J., Lee, B.J., andChou,T.Y., “Wireless Sensor Networks for Debris Flow Observation”2nd International Conference on Urban Disaster Reduction, 2007.MUSALIAR COLLEGE OF ENGINEERING AND TECHNOLOGY 24
  • 25. MANAGING DISASTER WITH WIRELESS SENSOR NETWORKS[8] Corke, P., Peterson, R. and Rus, D. “Networked Robots: FlyingRobotNavigation Using a Sensor Net” in Dario, P. and Chatila, R.(Eds)“Robotics Research” STAR 15, 2005, pp. 234 – 243[9] Dantu, K., Rahimi, M., Shah, H., Babel, S., Dhariwal, A., andSukhatme, G. “Robomote: Enabling Mobility In Sensor Networks”IEEE/ACM International Conference Information Processing inSensor Networks (ISPN’05), Apr. 2005MUSALIAR COLLEGE OF ENGINEERING AND TECHNOLOGY 25