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Storing and reading sensor data from battery assisted passive RFIDZherdev, Filip January 2011 (has links)
Radio Frequency Identification (RFID) technology is an electronic labeling technique.These electronic labels are called tags and read wirelessly. In this thesis a battery and amicroprocessor are connected to the tag. The work consisted of programming themicroprocessor to transfers sensor data into the tags memory. The tags are placed ontrains and data is collected from sensors at the train's axle. That way sensor data can betransmitted from a train to readers stationed along the railroad tracks.The aim of the project is to predict service intervals. There is currently no possibility tosee wear in real time and stop a train before it breaks. At present, there is a form of heatdetectors located along the railroad tracks to measure temperatures of wheels and axlesof passing trains. These are expensive and have the disadvantage of being able to detecterrors that have already occurred, they can not detect errors that do not radiate heat.The thesis aims to provide a solution for this. By programming a microprocessor totransmit sensor data to the tags memory it is possible for an RFID reader to read thesensor data from the tag. Ensuring that data and identity can be read from the tag atspeeds up to 250 km/h, you can get the status of a trains wagon before it breaks.
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Design of an Antenna for a Wireless Sensor Network for TrainsHinnemo, Malkolm January 2011 (has links)
An antenna for a wireless sensor network for trains is designed and built. The network will monitor temperature and vibrations of the wheel bearings on the train wagons. Doing this will allow for an earlier detection of damaged wheels, which will ease planning of maintenance and reduce wear on the rails considerably. The requirement of the system is that it is to be installed without any cables attached to the sensor nodes. This calls for wireless communication, and that for that antennas are needed.A train is a difficult environment to transmit electromagnetic (EM) waves in. It is full of metal and EM-waves cannot pass through a conducting material. Having much metal in its vicinity also affects the function of the antenna. This needs to be taken into consideration when making the design.The constructed antenna is a small dual-layer patch antenna. Dual layer means that it is constructed out of two sheets known as substrates of isolating material with different characteristics. The lower one of these substrates is made in such a way that integration with a circuit board is possible. Such integration would reduce the production cost considerably. The antenna is designed for direct placement on a conducting surface. This surface could be part of the train. It uses the surrounding metal as a ground plane in order to reduce its size. The result is a small patch antenna with good radiation qualities in metallic surroundings. The longest side is 18.35 mm, equaling 14.9 % of the wavelength that the antenna is designed for. / WISENET
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Performance Comparison of Multi Agent Platforms in Wireless Sensor Networks.Bösch, Bernhard Bösch January 2012 (has links)
The technology for the realization of wireless sensors has been available for a long time, but due to progress and development in electrical engineering such sensors can be manufactured cost effectively and in large numbers nowadays. This availability and the possibility of creating cooperating wireless networks which consist of such sensors nodes, has led to a rapidly growing popularity of a technology named Wireless Sensor Networks (WSN). Its disadvantage is a high complexity in the task of programming applications based on WSN, which is a result of its distributed and embedded characteristic. To overcome this shortcoming, software agents have been identified as a suitable programming paradigm. The agent based approach commonly uses a middleware for the execution of the software agent. This thesis is meant to compare such agent middleware in their performance in the WSN domain. Therefore two prototypes of applications based on different agent models are implemented for a given set of middleware. After the implementation measurements are extracted in various experiments, which give information about the runtime performance of every middleware in the test set. In the following analysis it is examined whether each middleware under test is suited for the implemented applications in WSN. Thereupon, the results are discussed and compared with the author’s expectations. Finally a short outlook of further possible development and improvements is presented.
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Analysis of reliability and energy consumption in industrial wireless sensor networksErsvik, Johan January 2012 (has links)
Wireless sensor networks have attracted the interest of the process industry. A process plant typically contains thousands of devices, monitoring or controlling the process. Today, all these devices are usually connected with wires. Using wireless technology simplifies deployment of new devices in a network and eliminates the need for extensive wiring. But wireless communication is also more sensitive than its wired counterpart. Therefore work is needed to make wireless sensor networks a viable option in many applications. Important issues are, for example, robustness, energy efficiency, and latency. One of the leading communication protocols for industrial wireless sensor networks is the WirelessHART protocol. This thesis investigates three ways of improving performance of the protocol, in terms of reliability and energy requirements. First, the structure of a WirelessHART packet is studied and the removal of certain fields is suggested to make the communication overhead smaller. Second, forward error correcting codes are evaluated using simulations in MATLAB. Third, measurement experiments in actual industrial environments are conducted where radio signals are transmitted and received. The variability of the received signal strength is measured and the effect that polarization diversity has on the signal variability is analyzed. The findings indicate that substantial improvements can be attained by employing polarization diversity, which can reduce channel variability and increase the expected signal strength significantly. The improvements in channel gain can be on the order of several tens of dB. The evaluations of forward error correcting codes show that the reliability is improved, with a channel gain of 3 dB. The study of the WirelessHART packet structure indicate that the packet sizes can be reduced by 15%. In turn, this also reduces energy requirements and packet error rates by 15%. This is equivalent to a gain in SNR on the order of a tenth of a dB.
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Data acquisition of pressure and heart beat rate using TinyOS for e-health care applicationBao, Zhixian January 2012 (has links)
The objective of the presented report focuses on the data acquisition of pressure and heart beat rates from external sensors over the TinyOS 2.x platform. This sensing application may be used in the e-health care field in order to sample the data information. The designed test-bed consists of several hardware devices, containing an MIB520CB USB interface board, two MICAz motes, an MDA300CA data acquisition board and external sensors for the pressure and heart beat rate. The programming language is NesC,which is used to build applications under the TinyOS 2.x environment. Data information is sampled from the external sensors, and this is then realized by the mote via the on-board ADC channel. The values are then transferred from one mote to another over radio communication. Finally, the expected results are transmitted to the PC by using serial communication. The report also discusses the sensing outcomes in order to determine the practical usage of the sensor devices. This project represents a common sensing application in wireless sensor networks, demonstrating a small case within the e-health care monitoring system. In order to meet the specific demands and to save resources, the wireless sensor networks are widely used in various applications. The designed test-bed could be also deployed as a part of larger-scale wireless sensor networks in order to achieve the requirements in relation to the sensing data information for further detailed use in future work.
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Open Secure Office Project : Wireless Sensor NetworkAndersson, Rikard, Sandberg, Martin, Urszuly, László January 2005 (has links)
In recent years, the development of wireless sensor networks has made a great progress. Early projects focused on replacement of existing systems equipped with wires. These systems started out as simple static data collection networks with one smart central node that could decide further actions based on the content of the collected data. Through time, the intelligence has become more decentralized, which means the nodes now can cooperate in a more efficient and dynamic manner. The task given is to evaluate TinyOS and NesC on specific hardware from Crossbow Technology Inc, applied on an application called the Open Secure Office Project. This application is designed to enhance the security without negative effects on comfort in a frequently visited open-plan office. Finally, a real world system demonstration should be performed. We propose a solution where there is no urgent need to cover the entire office area with radio signals to maintain a secure sensor system. This is true as long as all entries and exits to the office area are “guarded” by some base station which has as main task to keep track of people and equipment entering or leaving the office. Small scale tests have been performed which show that it is possible to easily develop and maintain a wireless sensor network security system, that could be coordinated by alternative systems.
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Effective Power Consumption in MAC Protocols for Wireless Sensor NetworksAugustin, Angelika January 2006 (has links)
Wireless sensor networks offer easy implementation, flexibility and mobility of hand held devices. Sensors consist of an internal power source, which is the great limitation for the life time and the usage of sensor networks. To increase the life time, sensors should stay in energy saving sleep mode as long as possible, because in sleep mode the radio is either shut down or working with less energy. Better energy handling is implemented in different power saving mechanism of common Medium Access Control protocols, which are evaluated and analyzed and further extensions and ideas to improve the energy efficiency are presented. Slotted PSM is simulated with the NS2 and compared to the WLAN 802.11 PSM technology and the results show that energy efficiency and power consumption are much better implemented and life time increases with the use of Slotted PSM.
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On Wireless Sensor Networks with Arbitary Correlated SourcesMahboubi, Seyyed Hassan January 2008 (has links)
An achievable rate region for general wireless sensor networks is proposed. A general multi-source, multi-relay, multi-destination wireless sensor network with arbitrarily correlated sources is considered. Each node can sense some real phenomena and send its readings to one or more sinks (data gathering nodes) via some relays. It also can relay some correlated or independent readings of other nodes, simultaneously. In this problem the source and channel coding separation is not optimal and the information which each reading has about others nodes is destroyed in separation. Thus, a joint source channel coding scheme can be used. The problem consists of relay channels and multiple access channels with arbitrarily correlated sources. The proposed scheme is based on regular block Markov encoding/backward decoding and code division multiple-access (CDMA) and the result is a combination of multi-relay and multiple-access with correlated sources.
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Reliable data delivery in wireless sensor networksYang, Bofu 21 June 2010 (has links)
Wireless sensor networks (WSN) have generated tremendous interest among
researchers these years because of their potential usage in a wide variety of applications.<p>
Sensor nodes are inexpensive portable devices with limited processing power and energy
resources. Sensor nodes can be used to collect information from the environment, locally
process this data and transmit the sensed data back to the user.<p>
This thesis proposes a new reliable data delivery protocol for general point-to-point
data delivery (unicasting) in wireless sensor networks. The new protocol is designed that
aims at providing 100% reliability when possible as well as minimizing overhead and
network delay. The design of the new protocol includes three components. The new
protocol adopts a NACK-based hop-by-hop loss detection and recovery scheme using
end-to-end sequence numbers. In order to solve the single/last packet problem in the
NACK-based approach, a hybrid ACK/NACK scheme is proposed where an ACK-based approach is used as a supplement to the NACK-based approach to solve the single/last packet problem. The proposed protocol also has a new queue management scheme that gives priority to new data. By introducing the idea of a Ready_Bit and newer packet first
rule in the transmission queue, nodes can detect and recover lost packets in parallel with
the normal data transmission process.
The performance of the new protocol is tested in a Crossbow MicaZ testbed.
Experimental results show that the new protocol performs well under various system and
protocol parameter settings.
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Object Tracking in Wireless Sensor Networks by Mobile Agent and Mining Movement PatternsTsai, Chung-han 04 August 2010 (has links)
With the advances of wireless communications and micro-electronic device technologies, wireless sensor networks have been applied in a wide spectrum of applications, including one of the killer applications--object tracking. Among numerous challenges in object tracking, one of the important issues is the energy management. One solution to the above issue is the mobile agent-based paradigm. Using the mobile agent in wireless sensor networks has many advantages over the client/server paradigm in terms of energy consumptions, networks band-width, etc. In this thesis, we adopt the mobile agent-based paradigm to support object track-ing in wireless sensor networks.
Although using the mobile agents for object tracking can improve the overall perfor-mance, the hurdle is the determination of the mobile agent itinerary. The past studies on ob-ject tracking considered the object¡¦s movement behavior as randomness or the direction and the speed of the object remain constant for a certain period of time. However, in most real-world cases, the object movement behavior is often based on certain underlying events rather than randomness complete. With this assumption, the movements of objects are some-times predictable. Through the prediction, the mobile agent can determine which node to mi-grate in order to reduce energy consumption and increase the performance of object tracking. In this thesis, we develop a mining-based approach to discover the useful patterns from the object¡¦s movement behavior. This approach utilizes the discovered rules to choose the sensor node the mobile agent needs to migrate in order to reduce the number of wrong migration, to reduce total energy consumed by sensor nodes, and to prolong the lifetime of the wireless sensor network. Experimental results show the efficiency of the proposed approach.
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