Applications of wireless sensor networks

Applications of Wireless Sensor Networks 2 APPLICATIONS OF WIRELESS SENSOR NETWORKS 2 1 INTRODUCTION WSNs are collections of compact size, relatively inexpensive computational nodes that measure local.

2 APPLICATIONS OF WIRELESS SENSOR NETWORKS 2.1 INTRODUCTION WSNs are collections of compact-size, relatively inexpensive computational nodes that measure local environmental conditions or other parameters and forward such information to a central point for appropriate processing WSNs nodes (WNs) can sense the environment, can communicate with neighboring nodes, and can, in many cases, perform basic computations on the data being collected WSNs support a wide range of useful applications In this chapter we identify some of these applications; the chapter is not intended to be exhaustive, simply illustrative 2.2 BACKGROUND In Chapter we taxonomized (commercial) sensor networks and systems into two basic categories:
Category WSNs (C1WSNs): almost invariably mesh-based systems with multihop radio connectivity among or between WNs, utilizing dynamic routing in both the wireless and wireline portions of the network Militarytheater systems typically belong to this category
Category WSNs (C2WSNs): point-to-point or multipoint-to-point (starbased) systems generally with single-hop radio connectivity to WNs, utilizing Wireless Sensor Networks: Technology, Protocols, and Applications, by Kazem Sohraby, Daniel Minoli, and Taieb Znati Copyright # 2007 John Wiley & Sons, Inc 38 BACKGROUND 39 static routing over the wireless network; typically, there will be only one route from the WNs to the companion terrestrial/wireline forwarding node (WNs are pendent nodes) Residential control systems typically belong to this category C2WSNs are networks in which end devices (sensors) are one radio hop away from a terrestrially homed forwarding node (see Figure 2.1) The forwarding node (call it a wireless router) is connected to the terrestrial network via either a landline or a point-to-point wireless link The important characterizations are that (1) sensor nodes (i.e., the WNs) not support communications on behalf of any other sensor nodes; (2) the forwarding node supports only static routing to the terrestrial network, and/or only one physical link to the terrestrial network is present; (3) the radio link is measured in hundreds of meters; and (4) the forwarding node does not support data processing or reduction on behalf of the sensor nodes In effect, these are relatively simple wireless systems C1WSNs are networks in which end devices (sensors) are permitted to be more than one radio hop away from a routing or forwarding node (see Figure 2.2) The forwarding node is a wireless router that supports dynamic routing (i.e., it has a mechanism that is used to find the best route to the destination out of a possible set of more than one route); wireless routers are often connected over wireless links The important characterizations are that (1) sensor nodes can support communications Figure 2.1 routing Category WSNs: point-to-point, generally-singlehop systems utilizing static 40 APPLICATIONS OF WIRELESS SENSOR NETWORKS Dynamic route wireless router Data Sink Point r r r r r Dynamic route wireless router Dynamic route wireless router End device r Dynamic route wireless router r r r Dynamic route wireless router r r r r r r r r End device r r r Dynamic route wireless router r r r r r Dynamic route r wireless router r End device Dynamic route wireless router r End device Figure 2.2 routing Category WSNs: multipoint-to-point, multihop systems utilizing dynamic on behalf of other sensor nodes by acting as repeaters; (2) the forwarding node supports dynamic routing and more than one physical link to the rest of the network is physically and logically present; (3) the radio links are measured in thousands of meters; and (4) the forwarding node can support data processing or reduction on behalf of the sensor nodes These are relatively complex and ‘‘meshy’’ wireless systems Some refer to the two types of behavior as cooperative (when a node forwards information on behalf of another node) or noncooperative (when a node handles only its own communication) [2.54] (see Figure 2.3) The two categories of WSNs are intended to be mutually exclusive by definition.1 WSNs (particularly C1WSNs) typically consist of hundreds (even thousands) of inexpensive WNs Figure 2.3 Cooperative and noncooperative nodes The mutual exclusivity is reasonably well but not perfectly described by the definitions provided for the two classes BACKGROUND 41 The WNs have computational power and sensing capabilities and typically operate in an unattended mode; they are battery-, piezoelectrically-, or solar-powered The technical implications of the network environment (multihop/dynamic routing versus singlehop/static routing) are discussed in subsequent chapters Although other classifications are possible, particularly for the technology itself (see Section 2.6), applications are discussed here according to the categorization just described Namely, as a practical matter we look at applications supported by C1WSNs as being distinct from applications supported by C2WSNs.2 Basically, we see two groups of applications: those that typically entail point-to-point systems and those that entail complex or dynamic mesh multihop systems Category applications are most-often supported by and delivered over C1WSNs Category applications are most-often supported by and delivered over C2WSNs Distributed WSNs using sensor and microsensor technology are expected to enable a plethora of applications for sensing and controlling the physical world for commercial as well as military purposes Applications range from environmental control (e.g., tracking soil contamination, habitat monitoring), warehouse inventory, and health care at one end of the spectrum, to scientific and military uses at the other [2.1–2.4] In recent years, particularly since the beginning of this decade, WSN research has undergone a revolution; the advances originating from this research promise to have a significant impact on a broad range of applications relating to national security, health care, the environment, energy, food safety, and manufacturing, to list just a few [2.5] The range of potential applications is really limited only by the imagination; examples include tracking wild fires; microclimate assessment; monitoring animal populations; defense systems; enabling businesses to monitor and control workspaces; and allowing authorities to monitor for toxic chemicals, explosives, and biological agents, to list only a few [2.7] Law-enforcement WSNs offer functional capabilities and enhancements in operational efficiency in civilian applications; this technology can also assist in the effort to increase alertness to potential terrorist threats [2.6] National defense relies on accurate intelligence, surveillance, and reconnaissance (ISR) The utilization of a dense set of small affordable sensors that are deployed appropriately in the environment of interest has the potential to increase the dependability of ISR systems because of the fact that a large set of redundant sensors decreases the vulnerability of the system to failure However, in applications such as these, the ability to combine information becomes a critical factor in managing network bandwidth and facilitating ultimate decision making [2.8] There has been extensive academic research on WSNs over the recent past, as we noted in Chapter 1, but for all intents and purposes, until open technical standards take hold pervasively, applications and deployment will remain specialized Although a topic is strictly at the research level, there is a lot of academic interest; however, as standards begin to take hold, the topic becomes more practical and To be exact, C2WSN-like applications could be supported (but perhaps not cost-effectively) by C1WSNs; however, C1WSN-like applications cannot generally be supported by C2WSNs 42 APPLICATIONS OF WIRELESS SENSOR NETWORKS the technical development becomes more pragmatic We believe that, in fact, we have reached this inflection point with regard to WSNs The convergence of the Internet, wireless communications, and information technologies with techniques for miniaturization has placed sensor technology at the threshold of an era of significant potential growth [2.5] WSN hardware, particularly low-cost processors, miniature sensors, and low-power radio modules, are now becoming available under the thrust of emerging standards; further improvements in cost and capabilities are expected in the next few years, fostering additional deployment and applications Sensor networks typically operate at 900 MHz (868- and 915-MHz bands); commercially evolving systems will operate (via IEEE 802.11b or IEEE 802.5.4) in the 2.4-GHz range The market scope for WSNs is expected to see major expansion in the next three to five years; this expansion relates not only to science and engineering applications but also to a plethora of new consumer applications of the technology In the remainder of the chapter we survey some of the applications of WNS technology 2.3 RANGE OF APPLICATIONS As noted, WSNs support a broad spectrum of applications, ranging from environmental sensing to vehicle tracking, from perimeter security to inventory management, and from habitat monitoring to battlefield management (see Table 2.1) For example, WSNs may be deployed outdoors in large sensor fields to detect and control the spread of wild fires, to detect and track enemy vehicles, or to support environmental monitoring, including precision agriculture [2.9–2.12,2.51] Stakeholders are now focusing on developing applications that deliver measurable business value; the goal is to take the extensive body of research in this space and apply it to the real world [2.13–2.15] With WSNs one can monitor and control factories, offices, homes, vehicles, cities, the ambiance, and the environment For example, one can detect structural faults (e.g., fatigue-induced cracks) in ships, aircraft, and buildings; public-assembly locations can be equipped to detect toxins and to trace the source of the contamination Volcanic eruption, earthquake detection, and tsunami alerting—applications that generally require WNs deployed in remote, even difficult-to-reach locations—can be useful environmental-monitoring systems The following is a recent view expressed by the National Science Foundation [2.5] on WSNs: Emerging technologies will likely lead to a decrease in the size, weight and cost of sensors and sensor arrays by orders of magnitude, and they will lead to an increase the sensors’ spatial and temporal resolution and accuracy Large numbers of sensors may be integrated into systems to improve performance and lifetime, and decrease life-cycle costs Communications networks provide rapid access to information and computing, eliminating the barriers of distance and time for telemedicine, transportation, tracking endangered species, detecting toxic agents, and monitoring the security of civil and engineering infrastructures The coming years will likely see a growing reliance on and need for more powerful sensor systems, with increased performance and functionality RANGE OF APPLICATIONS TABLE 2.1 43 Applications Mentioned in This Chapter Air traffic control Appliance control (lighting and HVAC) Area and theater monitoring (military) Assembly line and workflow Asset management (e.g., container tracking) Automated automobile maintenance telemetry Automatic control of multiple home systems to improve conservation, convenience, and safety Automatic meter reading Automating control of multiple systems to improve conservation, flexibility, and security Automotive sensors and actuators Auto-to-auto applications (FCC recently approved specific frequencies for highway sensor and auto-to-auto applications; range is about 100 m [2.55]) Battlefield management Battlefield reconnaissance and surveillance Biological monitoring for agents Biomedical applications Blinds, drapery, and shade controls Body-worn medical sensors Borders monitoring (Mexican and Canadian borders) Bridge and highway monitoring (safety) Building and structures monitoring Building automation (security, HVAC, automated meter reading, lighting control, access control) Building energy monitoring and control Capturing highly detailed electric, water, and gas utility usage data Centibots (DARPA): embedded mobile sensor nodes; 100 robots mapping, tracking, and guarding an environment in a coherent manner Chemical, biological, radiological, and nuclear wireless sensors (sensors for toxic chemicals, explosives, and biological agents) Civil engineering applications Collection of long-term databases of clinical data (enables correlation of biosensor readings with other patient information) Combat field surveillance Commercial applications Commercial building control Configuring and running multiple home control systems from a single remote control Consumer applications Consumer electronics and entertainment (TV, VCR, DVD/CD) Consumers’ ability to keep track of their belongings, pets, and young children Control of temperature Controlling the spread of wild fires Critical infrastructure protection and security Defense systems Detecting an impulsive event (e.g., a footstep or gunshot) or vehicle (e.g., wheeled or tracked, light or heavy) Detecting structural faults in aircraft Detecting structural faults in buildings (e.g., fatigue-induced cracks) Detecting structural faults in ships Detecting toxic agents (Continued) 44 TABLE 2.1 APPLICATIONS OF WIRELESS SENSOR NETWORKS (Continued ) Detection and tracking of enemy vehicles Disaster management Distributed robotics Distributed sensing (military) Earthquake detection Electricity load management Embedding intelligence to optimize consumption of natural resources E-money/point-of-sale applications (including kiosks) Enabling businesses to monitor and control workspaces Enabling deployment of wireless monitoring networks to enhance perimeter protection Enabling extension and upgrading of building infrastructure with minimal effort Enabling installation, upgrading, and networking of home control system without wires Enabling networking and integration of data from multiple access control points Enabling rapid reconfiguring of lighting systems to create adaptable workspaces Energy management Environmental (land, air, sea) and agricultural wireless sensors Environmental control (e.g., tracking soil contamination, habitat monitoring) Environmental monitoring, including precision agriculture Environmental sensing applications Equipment management services and preventive maintenance Extending existing manufacturing and process control systems reliably Facilitating the reception of automatic notification upon detection of unusual events Farm sensor and actuator networks (monitoring soil moisture, feeding pigs, unmanned tractor control) Flexible management of lighting, heating, and cooling systems from anywhere in the home Food safety Gas, water, and electric meters Gateway or field service links to sensors and equipment (monitored to support preventive maintenance, status changes, diagnostics, energy use, etc.) Habitat monitoring Habitat sensing Health care Heartbeat sensors Heating control Helping automate data acquisition from remote sensors to reduce user intervention Helping deploy monitoring networks to enhance employee and public safety Helping identify inefficient operation or poorly performing equipment Helping streamlining data collection for improved compliance reporting Herd control from central location using sensor-based fences and remote-controlled gates Home automation, including alarms (e.g., an alarm sensor that triggers a call to a security firm) Home control applications to provide control, conservation, convenience, and safety Home monitoring for chronic and elderly patients (collection of periodic or continuous data and upload to physicians) Home security Homeland Security Advanced Research Projects Agency, which has the goal of developing a national sensor net to detect biological, chemical, and nuclear agents Hotel energy management RANGE OF APPLICATIONS TABLE 2.1 45 ðContinued Þ HVAC control iBadge (UCLA): used to track the behavior of children or patients (e.g., speech recording/replaying, position detection, direction detection, local climate: temperature, humidity, pressure) iButton: a small computer chip enclosed in a stainless steel container that looks like a button containing up-to-date information that can travel with a person or object (e.g., be used wirelessly with an ATM or vending machine) IEEE 802.15.4 mote (Telos is first 802.15.4-based mote; 2/2004; www.moteiv.com) Improving asset management by continuous monitoring of critical equipment Industrial and building automation Industrial and building monitoring Industrial and manufacturing automation Industrial automation applications that provide control, conservation, and efficiency Industrial control (asset management, process control, environmental, energy management) Industrial monitoring and control Integrating and centralizing management of lighting, heating, cooling, and security Intrusion detection Inventory control Inventory management Law enforcement Lighting control Localization Manufacturing control Mass-casualties management Materials processing systems (heat, gas flow, cooling, chemical) Medical disaster response Medical sensing and monitoring Metropolitan operations (traffic, automatic tolls, fire, etc.) Microclimate assessment and monitoring Military applications Military command, control, communications, intelligence, and targeting systems Military sensing Military sensor networks to detect and gain information about enemy movements Military tactical surveillance Military vigilance for unknown troop and vehicle activity Mobile robotics Monitoring and controlling cities Monitoring and controlling factories Monitoring and controlling homes Monitoring and controlling offices Monitoring and controlling the ambiance Monitoring and controlling the environment Monitoring and controlling vehicles Monitoring animal populations Monitoring complex machinery and processes/condition-based maintenance (CBM) Monitoring for explosives Monitoring for toxic chemicals (Continued) 46 TABLE 2.1 APPLICATIONS OF WIRELESS SENSOR NETWORKS ðContinued Þ Monitoring intersections Monitoring on-truck and on-ship tamper of assets Monitoring rooftops (military) Monitoring the limb movements and muscle activity of stroke patients during rehabilitation exercise Monitoring the security of civil and engineering infrastructures Monitoring wild fires Nanoscopic sensor applications (e.g., biomedics) National defense National security Near field communication (NFC) as a ‘‘virtual connector’’ (NFC acts like RFID but requires close proximity to read, providing easy identification and security; wireless connectivity needed to transport data [2.55,2.58]) Nose-on-a-chip (Oak Ridge National Laboratory): a MEMS-based sensor that can detect 400 types of gases and transmit information to a central control station, indicating the level Perimeter security Personal health diagnosis Personal health care (patient monitoring, fitness monitoring) Pervasive computing (‘‘invisible computing,’’ ‘‘ubiquitous computing’’) Physical security Pre-hospital and in-hospital emergency care Preventive maintenance for equipment used by a semiconductor fabricator Process control Production processing Providing detailed data to improve preventive maintenance programs Public assembly locations monitoring Public-safety applications Quality-of-life applications Radar used to profile soil composition in vineyards (UC–Berkeley) Radiation and nuclear-threat detection systems Real-time collection of data (e.g., to check temperature or monitor pollution levels) Real-time continuous patient monitoring (e.g., pre-hospital, in-hospital, and ambulatory monitoring) Reducing energy costs through optimized manufacturing processes Reducing energy expenses through optimized HVAC management Refrigeration cage or appliance monitoring Remote underwater sampling station (RUSS) robots used to monitor municipal water supplies; the WNs are solar-powered robots that float on the surface and deploy descendable sensors underwater to sample temperature, oxygen, turbidity, light, and salt content; data are transmitted by cell phone to central lab and posted on the Web [2.55] Remotely-controlled home heating and lighting Remotely monitored assets, billing, and energy management Residential control and monitoring applications Residential/light commercial control (security, HVAC, lighting control, access control, lawn and garden irrigation) RF-based localization RFID tags RANGE OF APPLICATIONS TABLE 2.1 47 ðContinued Þ Ring sensor (MIT): monitors the physiological status of the wearer and transmits the information to a medical professional over the Internet Routing, naming, discovery, and security for wireless medical sensors, personal digital assistants, PCs, and other devices Scientific applications Security services (including peel-n’-stick security sensors) Seismic accelerometers (devices able to measure movement) Sensor networks for theme parks Sensor networks to detect and characterize chemical, biological, radiological, nuclear, and explosive attacks and material Sensor networks to detect and monitor environmental changes in plains, forests, and oceans Sensors embedded in a glacier in Norway (pelletlike WNs are embedded 60 m inside a glacier and use collaborative methods to collect and transmit data) [2.55] Sensors in chimneys to monitor creosote buildup Smart bullet fired from a paintball gun (wireless transmitter and battery capable of a range of 70 m) [2.57] Smart bricks: accelerometer/thermistor/etc embedded in bricks (UIUC) Smart kindergarten project (Mani Srivastava/UCLA): I-badges embedded in children’s hats to track position, bearing, and record sound; classroom toys have sensors embedded to detect use Smart structures that are able to self-diagnose potential problems and self-prioritize requisite repairs Smoke, CO, and H2O detectors Stroke patient rehabilitation Supermarket management Supporting the straightforward installation of wireless sensors to monitor a wide variety of conditions Telemedicine Toxin detection Tracing source of contamination Tracking criminals Tracking endangered species Tracking wild fires Traffic light sensors and control (using distributed greedy algorithms) [2.56] Traffic flow and surveillance Tsunami alerting Turf cam microcameras (about 0.5 cm3) placed throughout a football field [2.55] Underfloor air distribution systems Universal remote control to a set-top box Vehicle tracking Video surveillance Virtual fence using a sensor or actuator as a collar (Dartmouth College is using Wi-Fi PDA collars) Vital sign data, such as pulse oximetry and two-lead EKG (medical) Volcanic eruptions Warehouse inventory Warehouses, fleet management, factory, supermarkets, and office complexes (Continued) ... engineering applications but also to a plethora of new consumer applications of the technology In the remainder of the chapter we survey some of the applications of WNS technology 2.3 RANGE OF APPLICATIONS. .. 40 APPLICATIONS OF WIRELESS SENSOR NETWORKS Dynamic route wireless router Data Sink Point r r r r r Dynamic route wireless router Dynamic route wireless router End device r Dynamic route wireless. .. installation of wireless sensors to monitor a wide variety of conditions
Sensing applications facilitate the reception of automatic notification upon detection of unusual events Body-worn medical sensors