• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 84
  • 46
  • 44
  • 12
  • 9
  • 9
  • 6
  • 6
  • 5
  • 3
  • 1
  • 1
  • 1
  • Tagged with
  • 244
  • 112
  • 79
  • 70
  • 64
  • 63
  • 45
  • 34
  • 29
  • 28
  • 27
  • 22
  • 22
  • 21
  • 20
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
211

Měření vzdálenosti pomocí technologie ZigBee / Distance measurement by ZigBee technology

Čepl, Josef January 2010 (has links)
The master's thesis deals with problems which is associated with rough detection of distance between wireless modules based on ZigBee technology. In the first logical part it theoretically describes this technology and their characteristics. This section gives basic informations needed to understand the operation of wireless communications and also acquaint him with some of the terms from this sphere. Next thing is description of the medium access together with a detailed description of functions that are crucial for deter-mining the signal strength. The second part is devoted to describe the 1321XDSK-BDM development kit. Another section is devoted to the design of the user's interface for displaying measured data. It consists of a theoretical design, which describes the initial vision of the device accompanied by solution of communication between wireless module and the proposed device. Follows the design of the involvement in Eagle software and explanation of the various components. In the last two chapters of the whole logical structure is described construction of the device and simple user's guide. The following chapter talks about the selection of suited application, necessary changes and own implementation of source code. There is even a description of important features and components of the application. The penultimate chapter contains a distance measurement in terrain using wireless modules and designed device. Here are tested different influences on the final distance measurement accuracy. In conclusion there is a debate over the results achieved. Particular, this section includes an assessment of precision measuring methods and evaluates aplicability of this method in practice.
212

Návrh paketového analyzátoru pro bezdrátové senzorové sítě založené na standardu IEEE 802.15.4 / Packet analyser for a Wireless Sensor Networks based on the standard IEEE 802.15.4

Bednařík, Martin January 2011 (has links)
The objective of this thesis is to get familiar with wireless sensor networks technologies and with standard IEEE 802.15.4. and communication principle in wireless sensor networks built on this standard. Main goal of this project is to design a packet analyzer, which is capable to catch data on chosen channel and this data is able to analyze. Part of this project is production of necessary microcontroller software equipment. Another output of this project is do a research of available packet analyzers on market and compare them with analyzer build by this thesis.
213

Bezdrátové komunikační moduly pro mikrokontroléry / Wireless communication modules for microcontrollers

Klíma, Jan January 2011 (has links)
The aim of this master’s thesis is analysis of wireless communication between mikroprocesors. The first part of the work are analysed the problems the wireless free ISM band. Mainly RFM12B and ZigBee module, which i these band work and ZigBee standart. The second part are described relazation board for both module. Further how programming ZigBee module. And at last programs for tested module.
214

Simulační model veřejného osvětlení pro Network Simlator 3 / Simulation model of public light for Network Simulator 3

Kapoun, Vladislav January 2015 (has links)
This thesis is focused on the smart public lighting management possibilities. It describes smart public lighting management itself and the advantages of the new management possibilities compared to the current ones are illustrated as well. Furthermore, it deals with a comparison of the most used light resources and LED light resources. This thesis also outlines NS-3 simulation environment and states its advantages. Theoretical concept for energy-saving smart public lighting management system and its modifications for the needs of simulation is described in the paper. This theoretical concept is simulated and compared with the current smart public lighting management systems as well as with the systems designated by the third party.
215

Inteligentní senzorická síť navržená pro specifikaci 802.15.4 (beta aplikace) / Intelligent Sensory Net designed on the standard IEEE 802.15.4

Janšta, Tomáš January 2009 (has links)
This thesis focuses on design of wireless network nodes using modular construction parts with respect to IEEEŽ 802.15.4 standard. Presented platform joins the benefits of the XBeeŽ wireless module and the AVR ATmega128 microcontroller development system. Sensor network prototype is designed to meet the desired first attempt functionality of embedded platform for collection and delivery of small volumes of control and sensor data between the network and the gateway. The control software was developed for TinyOS operating system. Designed platform is used as the framework for future development and possible functionality extensions in related applications.
216

Zigbee-uppkopplat vattenlarm

Malmberg, Malin January 2020 (has links)
In this thesis project, a ZigBee-connected water alarm has been constructed. An Xbee 3 ZigBee radio module is programmed to send warnings to an other Xbee 3 ZigBee module if an analogue input falls below the threshold value. An PCB with the Xbee module, resistors, a transistor, LEDs and an battery attachment is manufactured and mounted. A sensor plate is made and attached to the PCB and connected with the analogue pin at the Xbee module. The water alarm works and can operate in large ZigBee networks, even with ZigBee products from other manufacturers. The water alarm can easily be hidden beneath a machine for a long time, it is slightly wider than a battery and with measurements every five minutes, abattery of 220 mAh will last more than 10 years. / Ett ZigBee-uppkopplat vattenlarm konstrueras. Radiomodulen Xbee 3 ZigBee programmeras till att skicka ett varningsmeddelande till en annan XBee 3 ZigBee-modul om värdet på en av de analoga ingångarna understiger ett gränsvärde. Ett kretskort tillverkas där XBee-modulen samt resistorer, en transistor, LED-lampor och ett batterifäste monteras. Även en sensorplatta tillverkas och monteras ihop med kretskortet så sensorn sammankopplas med den analoga ingången på XBee-modulen. Vattenlarmet fungerar och kan operera över stora ZigBee-nätverk, även innehållandes ZigBee-produkter av andra tillverkare. Eftersom vattenlarmet endast är någon millimeter bredare än sitt batteri är det platt och lätt att gömma under en maskin. Vattenlarmet är dessutom väldigt energisnålt, vid mätning efter vatten en gång var femte minut håller ett vanligt batteri på 220 mAh i över 10 år.
217

Smart Microgrid Energy Management Using a Wireless Sensor Network

Darden, Kelvin S 12 1900 (has links)
Modern power generation aims to utilize renewable energy sources such as solar power and wind to supply customers with power. This approach avoids exhaustion of fossil fuels as well as provides clean energy. Microgrids have become popular over the years, as they contain multiple renewable power sources and battery storage systems to supply power to the entities within the network. These microgrids can share power with the main grid or operate islanded from the grid. During an islanded scenario, self-sustainability is crucial to ensure balance between supply and demand within the microgrid. This can be accomplished by a smart microgrid that can monitor system conditions and respond to power imbalance by shedding loads based on priority. Such a method ensures security of the most important loads in the system and manages energy by automatically disconnecting lower priority loads until system conditions have improved. This thesis introduces a prioritized load shedding algorithm for the microgrid at the University of North Texas Discovery Park and highlight how such an energy management algorithm can add reliability to an islanded microgrid.
218

Analysis of the IEEE 802.15.4a ultra wideband physical layer through wireless sensor network simulations in OMNET++

Alberts, Marthinus 10 March 2011 (has links)
Wireless Sensor Networks are the main representative of pervasive computing in large-scale physical environments. These networks consist of a large number of small, wireless devices embedded in the physical world to be used for surveillance, environmental monitoring or other data capture, processing and transfer applications. Ultra wideband has emerged as one of the newest and most promising concepts for wireless technology. Considering all its advantages it seems a likely communication technology candidate for future wireless sensor networks. This paper considers the viability of ultra wideband technology in wireless sensor networks by employing an IEEE 802.15.4a low-rate ultra wideband physical layer model in the OMNET++ simulation environment. An elaborate investigation into the inner workings of the IEEE 802.15.4a UWB physical layer is performed. Simulation experiments are used to provide a detailed analysis of the performance of the IEEE 802.15.4a UWB physical layer over several communication distances. A proposal for a cognitive, adaptive communication approach to optimize for speed and distance is also presented. AFRIKAANS : Draadlose Sensor Netwerke is die hoof verteenwoordiger vir deurdringende rekenarisering in groot skaal fisiese omgewings. Hierdie tipe netwerke bestaan uit ’n groot aantal klein, draadlose apparate wat in die fisiese wêreld ingesluit word vir die doel van bewaking, omgewings monitering en vele ander data opvang, verwerk en oordrag applikasies. Ultra wyeband het opgestaan as een van die nuutste en mees belowend konsepte vir draadlose kommunikasie tegnologie. As al die voordele van dié kommunikasie tegnologie in ag geneem word, blyk dit om ’n baie goeie kandidaat te wees vir gebruik in toekomstige draadlose sensor netwerke. Hierdie verhandeling oorweeg die vatbaarheid van die gebruik van die ultra wyeband tegnologie in draadlose sensor netwerke deur ’n IEEE 802.15.4a lae-tempo ultra wyeband fisiese laag model in die OMNET++ simulasie omgewing toe te pas. ’n Breedvoerige ondersoek word geloots om die fyn binneste werking van die IEEE 802.15.4a UWB fisiese laag te verstaan. Simulasie eksperimente word gebruik om ’n meer gedetaileerde analiese omtrent die werkverrigting van die IEEE 802.15.4a UWB fisiese laag te verkry oor verskillende kommunikasie afstande. ’n Voorstel vir ’n omgewings bewuste, aanpasbare kommunikasie tegniek word bespreek met die doel om die spoed en afstand van kommunikasie te optimiseer. / Dissertation (MEng)--University of Pretoria, 2011. / Electrical, Electronic and Computer Engineering / unrestricted
219

Implementation and performance analysis of multiple concurrent WPAN protocols on a system-on-chip

Hag, Juni January 2022 (has links)
The development of new energy efficient Wireless Personal Area Network (WPAN) protocols is a big factor for the increased interest in Internet of Things (IoT). However, the many protocols with overlapping applications have led to competing standards and sensor networks using different protocols, even to perform the same tasks. If different sensors in IoT uses different protocols in the same area, a single gateway connecting to all of them must support all their protocols simultaneously. This thesis studies latency, average sending time and range for Bluetooth Low Energy (BLE), 802.15.4 and Zigbee in multiprotocol mode on the nRF52840 System on Chip (SoC). In addition, an 802.15.4-based protocol synchronizing with the BLE frames using Time Division Multiple Access (TDMA) techniques was designed and implemented. This protocol could be used in sensor networks using both the BLE and 802.15.4 protocols to assure the 802.15.4-based devices will not try to transmit during the periods the gateway is busy with other communications. / <p>Examensarbetet är utfört vid Institutionen för teknik och naturvetenskap (ITN) vid Tekniska fakulteten, Linköpings universitet</p>
220

State of Secure Application Development for 802.15.4

Armstrong, Janell 16 April 2009 (has links) (PDF)
A wireless sensor network consists of small, limited-resource embedded systems exchanging environment data and activating controls. These networks can be deployed in hostile environments to monitor wildlife habitats, implemented in factories to locate mobile equipment, and installed in home environments to optimize the use of utilities. Each of these scenarios requires network security to protect the network data. The IEEE 802.15.4 standard is designed for WSN communication, yet the standard states that it is not responsible for defining the initialization, distribution, updating, or management of network public keys. Individuals seeking to research security topics will find that there are many 802.15.4-compliant development hardware kits available to purchase. However, these kits are not easily compared to each other without first-hand experience. Further, not all available kits are suitable for research in WSN security. This thesis evaluates a broad spectrum of 802.15.4 development kits for security studies. Three promising kits are examined in detail: Crossbow MICAz, Freescale MC1321x, and the Sun SPOT. These kits are evaluated based on their hardware, software, development environment, additional libraries, additional tools, and cost. Recommendations are made to security researchers advising which kits to use depending on their design needs and priorities. Suggestions are made to each company on how to further improve their kits for security research.

Page generated in 0.0376 seconds