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Wireless Sensor Networks

Wireless Sensor Networks. Rob Roosendaal, Lecturer INHolland University. Agenda. Introduction Theoretical Background Practical Information Wrap up and questions. Introduction to Wireless Sensor Networks. Our projects. Alzheimer's disease ADL: Activities in Daily Life

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Wireless Sensor Networks

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  1. Wireless Sensor Networks Rob Roosendaal, Lecturer INHolland University

  2. rroosend@xs4all.nl Agenda • Introduction • Theoretical Background • Practical Information • Wrap up and questions

  3. rroosend@xs4all.nl Introduction to Wireless Sensor Networks

  4. rroosend@xs4all.nl Our projects • Alzheimer's disease • ADL: Activities in Daily Life • Acceptance of technologies • How to measure progress in ADL • Tablet as interface for easy acceptance • Sensor technology for detection • Sensor communication • Collecting data

  5. rroosend@xs4all.nl Crawling the web • Alzheimer's disease • Human computer interaction • Programming Android tablets • Connectiong devices to a tablet • Wireless Sensor Networks

  6. rroosend@xs4all.nl Alzheimer's disease • Memory loss that disrupts daily life • Challenges in planning or solving problems • Difficulty completing familiar tasks at home to work or at leisure • Confusion with time or place • Trouble understanding visual images and special relationships • New problems with words in speaking or writing • Misplacing things and loosing the ability to retrace steps • Decreased and poor judgement • Withdrawl from work or social activities • Change in mood and peronality

  7. rroosend@xs4all.nl Framework for Disseminating Data • Establish communications message (What should be said?) • Define the audience (To whom should it be said?) • Select the channel (Through what communication medium?) • Market the message (How should the message be stated?) • Evaluate the impact (What effect did the message create?) • Principles and Practice of Public Health Surveillance (Teutsch and Churchill, 2000)

  8. rroosend@xs4all.nl Wireless Sensor Network A wireless sensor network (WSN) of spatially distributed autonomous sensors to monitor physical or environmental conditions and to cooperatively pass their data through the network to a main location. The more modern networks are bi-directional, also enabling control of sensor activity. • http://en.wikipedia.org/wiki/Wireless_sensor_network

  9. rroosend@xs4all.nl Measuring physical parameters • Acoustic, sound, vibration • Automotive, transportation • Chemical • Electric current, electric potential, magnetic, radio • Environment, weather, moisture, humidity • Flow, fluid velocity • Ionizing radiation, subatomic particles • Navigation instruments • Position, angle, displacement, distance, speed, acceleration • Optical, light, imaging, photon • Pressure • Force, density, level • Thermal, heat, temperature • Proximity, presence • Sensor technology • Other sensors and sensor related properties and concepts • This is only a summarized list, the complete list of sensors you can use is about 400 items long !

  10. rroosend@xs4all.nl Measuring physical parameters • Focusing on healthcare, domotics and personal environment • Which sensors do we have?

  11. rroosend@xs4all.nl Points of interest IT • Autonomous sensors • Physical or environmental conditions • Cooperatively pass their data • Through the network to a main location • (Bi-directional, control of sensor activity)

  12. rroosend@xs4all.nl Autonomous sensors • Sensing + Processing + Communication • Prone to failure • Energy drain • Resource limitations: • Memory, Power, Processing • Sensor network architectures: • Layered, Clustered

  13. rroosend@xs4all.nl Physical or environmental conditions

  14. rroosend@xs4all.nl Cooperatively pass their data • Receive or transmit • Transmit if data has to be sent • Single-hop • Close by • Lower transmission rate • Multi-hop • Higher transmission rate • Less nodes available • Data-gathering wireless sensor networks: organization and capacity, • Enrique J. Duarte-Melo, Mingyan Liu

  15. rroosend@xs4all.nl Through the network to a main location • Wireless and wired network parts • Distributed routing, different routing protocols • Adapting to changes in connectivity • Real-time communication, connection oriented! • Quality of Service • Security

  16. rroosend@xs4all.nl Structure/Backbone (HW) • Hardware aspects • basic aspects (CPU, memory, radio) • specific sensors aspects (what type of signals are you measuring?)

  17. rroosend@xs4all.nl Structure/Backbone (SW) • Software aspects • Operating system • Network stack aspects • MAC layer aspects • Network layer aspects • Transport layer aspects • Application aspects

  18. rroosend@xs4all.nl Structure/Backbone

  19. rroosend@xs4all.nl Equipment • Tablet, running the app • Static computer for developing • Wireless sensor network to gather data and sent data to the tablet • Wireless network for the tablet to comunicate with the internet • Server for monitoring the app (compressed data)

  20. rroosend@xs4all.nl Wireless Sensor Node (1) • Sensor nodes • sensor technology • tiny battery driven computers • wireless communication interface • organize into a network • monitoring of processes, environmental conditions, events • act as routers • forward data cooperatively

  21. rroosend@xs4all.nl Wireless Sensor Node (2) 4 1 3 5 2

  22. rroosend@xs4all.nl Wireless Sensor Node (3) 1/5 6 7

  23. rroosend@xs4all.nl Classifications of sensor network protocols

  24. rroosend@xs4all.nl Clustered sensor network architecture • Organizes the sensor nodes into clusters • Each cluster is governed by a cluster-head • Only heads send messages to a BS • Suitable for data fusion • Self-organizing

  25. rroosend@xs4all.nl Layered sensor network architecture • Short-distance, low power • Unified Network Protocol Framework (UNPF) • Integrates three operations: • Network Initialization & Maintenance Protocol • MAC Protocol • Routing Protocol

  26. rroosend@xs4all.nl Network Initialization & Maintenance Protocol • Base Station (BS) broadcasts ID using Code Division Multiple Access (CDMA) common control channel (BS reaches all nodes in one hop) • Nodes record BS ID & send beacon signal with their own IDs at their low default power levels • All nodes the BS can hear are at 1-hop distance • The BS broadcasts a control packet with all layer one node IDs • All nodes send a beacon signal again • The layer one nodes record the IDs they hear-layer 2 • The layer one nodes inform the BS of the layer 2 • The BS broadcasts the layer2 nodes IDs,… • To maintain: periodic beaconing updates are required

  27. rroosend@xs4all.nl Routing Protocol • Downlink from the BS is by direct broadcast on the control channel • Enables multi-hop data forwarding to the BS • The remaining energy is considered when forwarding to the next hop (layer) • Only the nodes of the next layer need to be maintained in the routing table

  28. rroosend@xs4all.nl Low-Energy Adaptive Clustering Hierarchy (LEACH) • Self-organizing and adaptive clustering protocol • Evenly distributes the energy expenditure among the sensors • Performs data aggregation where cluster heads act as aggregation points • Two main phases: • Setup phase: organizing the clusters • Steady-state phase: deals with the actual data transfers to the BS

  29. rroosend@xs4all.nl Low-Energy Adaptive Clustering Hierarchy (LEACH) • Merits: • Accounting for adaptive clusters and rotating cluster heads • Opportunity to implement any aggregation function at the cluster heads • Demerits: • Highly dynamic environments • Continuous updates • Mobility

  30. rroosend@xs4all.nl Efficient Data Gathering in WSN • Data gathering from different correlated • cues from the network stateuses hints or cues about the physical environment to optimize network behavior • energy-efficient rooted aggregation treesa simple, scalable and distributed correlation-aware aggregation structure • congestion reduction techniquesproviding congestion control from the sink to the sensors in a sensor field

  31. rroosend@xs4all.nl Medium Access Control • Framing • Frame format and data en- and decapsulation • Medium Access • Which devices participate in communication at what time • Reliability • Successful transmission between devices • Flow Control • Prevent frame loss through buffer overloads • Error Control • Error detection or correction

  32. rroosend@xs4all.nl Location discovery? • Distance estimation • Techniques to estimate the relative distance between nodes • Position computation • Calculate coordinates based on known other nodes • Triangulation, multilateration, proximity • Localization • Based on information about distances and positions

  33. rroosend@xs4all.nl Leftovers • Quality of network coverage • Security • Real time communication • ...

  34. rroosend@xs4all.nl Conclusion

  35. rroosend@xs4all.nl The internet of things is close! • What we can do: • Acquired data • Reports or alarm notices • Automatically forwarded to information systems

  36. rroosend@xs4all.nl The internet of things is close! • What we can do with this technology: • Extending the internet into the real-world • Autonomous Information Systems • Automatically update themselves • Synchronize with the actual state of monitored structure or process

  37. rroosend@xs4all.nl The internet of things is close! • What we can do with this technology: • Near-real-time information enables early intervention • Prevent abnormal behavior • Malfunction • Damages • Dangerous situations

  38. rroosend@xs4all.nl The internet of things is close! • Typical application domains: • Home care and e-health (or t-health) • Environmental monitoring • Factory automation and maintenance • Supply chain and asset management • Physical security and control • …

  39. rroosend@xs4all.nl Practical Information

  40. rroosend@xs4all.nl Wireless Sensor Network • Coalesenses • Wireless Sensor Technology • Wireless Sensor Modules • Wireless Sensor Solutions • Solar Power Harvesting • Wireless Sensor Devices • ... • http://www.coalesenses.com/

  41. rroosend@xs4all.nl Wireless Sensor Modules The iSense modular hardware and software platform for wireless networks for industry and research applications comprises modules for wireless networking, sensors modules, different power supplies, solar power harvesting, interfaces to PCs, GPS and more.

  42. rroosend@xs4all.nl Wireless Sensor Solutions Based upon a broad range of hardware, software and protocol components as well as our different networking devices, coalesensesoffersboth standardized as well as customer specific wireless sensor networking systems.

  43. rroosend@xs4all.nl Solar Power Harvesting The iSense Solar Power Harvesting System is an out-of-the-box solution for running self-powered wireless sensor networks. By harvesting solar energy and storing it in a rechargeable battery, it allows to operate sensor nodes all-time autonomously

  44. rroosend@xs4all.nl Wireless Sensor Devices coalesenses offers a number of different devices as building blocks for wireless systems, ranging from LAN gateways over repeaters to USB sticks.

  45. rroosend@xs4all.nl Wireless Sensor Technology coalesenses offers a collection of hardware and software for wireless sensor networks, a technology for literally giving eyes and ears to modern control and information systems.

  46. rroosend@xs4all.nl Wrapup and Questions

  47. rroosend@xs4all.nl Wrap up • Environment: • Health, Alzheimers • Domotics, Wireless Sensor Networks • IT, Tablet and internet connection • Main question: • How can we add value to the life of a patient with Alzheimers

  48. rroosend@xs4all.nl What is next?

  49. rroosend@xs4all.nl Questions

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