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  • 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.
31

Study of Wired and Wireless Data Transmissions

Huynh, Allan January 2010 (has links)
The topic of this dissertation is divided into two parts where the first part presents high-speed data transmission on flexible cables and the second part presents a wireless remote monitoring and controlling system with wireless data transmission. The demand on high-speed data communications has pushed both the wired and wireless technologies to operate at higher and higher frequencies. Classic Kirchhoff’s voltage and current laws cannot be directly applied, when entering the microwave spectrum for frequency above 1 GHz. Instead, the transmission line theory should be used. Most of the wired communication products use bit-serial cables to connect devices. To transfer massive data at high speed, parallel data transfer techniques can be utilized and the speed can be increased by the number of parallel lines or cables, if the transfer rate per line or cable can be maintained. However, the lines or cables must be well-shielded so the crosstalk between them can be minimized. Differential lines can also be used to increase the data speed further compared to the single-ended lines, along with saving the power consumption and reducing the electromagnetic interference. However, characterization for differential lines is not as straight forward as for single-ended cases using standard S-parameters. Instead, mixed-mode S-parameters are needed to describe the differential-, common- and mixed-mode characteristics of the differential signal. Mixed-mode S-parameters were first introduced in 1995 and are now widely used. However, improvements of the theory can still be found to increase the accuracy of simulations and measurements, which is proposed and presented in this dissertation. The interest of wireless solution to do remote control and monitoring for cultural building has been increasing. Available solutions on the market are mostly wired and very expensive. The available wireless solutions often offer limited network size with point-to-point radio link. Furthermore, the wired solution requires operation on the building, which is not the preferred way since it will damage the historical values of cultural heritage buildings. Wireless solutions on the other hand can offer flexibility when deploying the network, i.e., operation on the building can be avoided or kept to the minimum. A platform for wireless remote monitoring and control has been established for various deployments at different cultural buildings. The platform has a modular design to ease future improvement and expansion of the system. The platform is based on the ZigBee standard, which is an open standard, specified with wireless sensor network as focus. Three different modules have been developed. The performance has been studied and optimized. The network has been deployed at five different locations in Sweden for data collection and verification of the system stability. The remote monitoring and control functions of the developed platform have received a nomination for the Swedish Embedded Award 2010 and been demonstrated at the Scandinavia Embedded Conference 2010 in Stockholm.Communication
32

Thin Film Electroacoustic Devices for Biosensor Applications

Wingqvist, Gunilla January 2009 (has links)
Biosensors are today important devices within various application areas. In this thesis a new type of label-free biosensor device is studied, which is fabricated using the same processes used for the fabrication of integrated circuits. This enables tighter integration and further sensors/biosensor miniaturization. The device is a so-called Thin Film Bulk Acoustic Resonator (FBAR). Within this thesis a low temperature reactive sputtering process for growing AlN thin films with a c-axis inclination of 20-30o has been developed. This enables shear mode FBAR fabrication suitable for in-liquid operation, essential for biosensor applications. Shear mode FBARs were fabricated operating at frequencies above 1GHz exhibiting Q values of 100-200 in water and electromechanical coupling factors kt2 of about 1.8%. This made it possible to move the thickness excited shear mode sensing of biological layers into a new sensing regime using substantially higher operation frequencies than the conventionally used quartz crystal microbalance (QCM) operating at 5-20MHz. Measured noise levels of shear mode FBARs in contact with water showed the resolution to be in the range 0.3ng/cm2 to 7.5ng/cm2. This demonstrated the FBAR resolution without any averaging or additional stabilization measures already to be in the same range as the conventional QCM (5ng/cm2), suggesting that FBARs may be a competitive and low cost alternative to QCM. The linear thickness limit for sensing of biomolecular layers was concluded to be larger than the thickness of the majority of the molecular systems envisaged for FBAR biosensor applications. A temperature compensated shear mode FBAR composite structure was demonstrated with retained coupling factor and Q-value by utilizing the second mode of operation. Understanding has been gained on the sensor operation as well as on how the design parameters influence its performance. Specifically, sensitivity amplification utilizing low acoustic impedance layers in the FBAR structure has been demonstrated and explained. Further, temperature compensated Lamb mode (FPAR) devices were also studied and demonstrated with optimized electromechanical couplings. / wisenet
33

Memory Synthesis for FPGA Implementation of Real-Time Video Processing Systems

Lawal, Najeem January 2009 (has links)
In this thesis, both a method and a tool to enable efficient memory synthesis for real-time video processing systems on field programmable logic array are presented. In real-time video processing system (RTVPS), a set of operations are repetitively performed on every image frame in a video stream. These operations are usually computationally intensive and, depending on the video resolution, can also be very data transfer dominated. These operations, which often require data from several consecutive frames and many rows of data within each frame, must be performed accurately and under real-time constraints as the results greatly affect the accuracy of application. Application domains of these systems include machine vision, object recognition and tracking, visual enhancement and surveillance. Developments in field programmable gate arrays (FPGAs) have been the motivation for choosing them as the platform for implementing RTVPS. Essential logic resources required in RTVPS operations are currently available and are optimized and embedded in modern FPGAs. One such resource is the embedded memory used for data buffering during real-time video processing. Each data buffer corresponds to a row of pixels in a video frame, which is allocated using a synthesis tool that performs the mapping of buffers to embedded memories. This approach has been investigated and proven to be inefficient. An efficient alternative employing resource sharing and allocation width pipelining will be discussed in this thesis. A method for the optimised use of these embedded memories and, additionally, a tool supporting automatic generation of hardware descriptions language (HDL) modules for the synthesis of the memories according to the developed method are the main focus of this thesis. This method consists of the memory architecture, allocation and addressing. The central objective of this method is the optimised use of embedded memories in the process of buffering data on-chip for an RVTPS operation. The developed software tool is an environment for generating HDL codes implementing the memory sub-components. The tool integrates with the Interface and Memory Modelling (IMEM) tools in such a way that the IMEM’s output - the memory requirements of a RTVPS - is imported and processed in order to generate the HDL codes. IMEM is based on the philosophy that the memory requirements of an RTVPS can be modelled and synthesized separately from the development of the core RTVPS algorithm thus freeing the designer to focus on the development of the algorithm while relying on IMEM for the implementation of memory sub-components. / Electronics design division / Sensible Things that Communicate
34

Designing of High Reflectance Distributed Bragg reflectors (DBRs),mirrors using AlGaInN material system in the UV wavelength range

Bashir, Babar January 2009 (has links)
No description available.
35

Receiver Front-End Design for WiMAX/LTE in 90 nm CMOS : Receiver Front-End Design for WiMAX/LTE in 90 nm CMOS

Rabén, Hans January 2009 (has links)
No description available.
36

Demonstrator av vinkelgivare

Kivinen, Jonne January 2009 (has links)
Eskilstuna Elektronikpartner (EEPAB) är ett elektronikföretag som tillverkar vinkelgivare till bland annat kranar som är monterade på lastbilsflak. För att EEPAB på ett intressant sätt ska kunna demonstrera sin produkt på mässor har en demonstrator tagits fram. Denna demonstrator består av en fjärrstyrd grävmaskin och en elektronikenhet, som hanterar den analoga signalen från vinkelgivaren. Resultatet, som är vinkelgivarens lutning i grader, presenteras på två sjusegmentdisplayer som är placerade på grävmaskinens bägge sidor. Vinkeln skickas även trådlöst från elektronikenheten, via Bluetooth, till en PC. Grävmaskinens batteri (7,2V) strömförsörjer all hårdvara, vilket gör att demonstratorn är helt portabel. Denna rapport beskriver block för block de olika programfunktioner samt hårdvara, som behövs till en färdig och fungerande demonstrator. / Eskilstuna Elektronikpartner (EEPAB) is an electronics company located in Eskilstuna that produces angle sensors to, for instance, cranes mounted on truck beds. For EEPAB to be able to demonstrate their product on fairs in an interesting way, a demonstrator has been made. The demonstrator consists of a remote controlled excavator and an electronic unit which handles the analog signal from the sensor. The result, which is the angle of the sensor in degrees, is presented on two sevensegment displays that are placed on both sides of the excavator. The angle is also sent wirelessly from the electronic unit via Bluetooth to a PC. The battery of the excavator powers all of the hardware, making the demonstrator fully portable. This thesis report describes the various programfunctions and hardware, part by part, necessary for a complete and functioning demonstrator.
37

Halvautomatisk styrning av järnvägskran

Skoog, Björn January 2009 (has links)
En RMRC, Rail Mounted Railway Crane, är en kran för hantering av containertrafik till och från järnvägsvagnar. Kranen som är helt manuellt styrd utrustas med en semiautomatik som hjälper operatören att positionera kranen. Målpositionen för containern kommer från terminalens logistiksystem. För positioneringen har en lämplig regulator tagits fram som tar hänsyn till den mekaniska påverkan på motorer och växellådor som finns vid acceleration och retardation. Regulatorn har tagits fram och testats i en simuleringsmiljö. Den har sedan implementerats i ett PLC-system och provkörts i labmiljö med PLC och motorer. Regulatorn har förbättrad prestanda jämfört med den regulator som tidigare använts för andra typer av kranar. Den är också lättare att trimma in vid idriftsättning.För positionsåterföringen på de tre rörelserna lyft, tralla och kranåk, har olika typer av givare undersökts och rekommenderat.
38

Development of a collision avoidance system for a videoconferencing robot.

Björkman, Patrik, Odens Hedman, Lars January 2010 (has links)
The work presented in this paper is about the development of a collision avoidance systemfor a mobile telepresence robot developed by the company Gira technologies AB.The robot is designed to extend the length of time elderly can stay in their homes beforerequiring full-time staed care. The collision avoidance system is needed to help the userto avoid running in to objects or down a stairway. The design must be capable of beingimplemented at low cost, and should not look overtly "robotic" as this would not resultin an appealing industrial design. Herein, dierent techniques are presented and analyzed to nd the best suitable solutionfor the robot. In particular a lot of work is done in taking measurements to nd theright characteristics for the sensors according dierent mounting angles, dierent objectsand distances. A solution is chosen and calculations are made to nd the best positionsto place the sensors to get the best results. A complete solution is presented and implemented in the current system and testedto work as expected.
39

Development of a Multi‐bus platform for automation testbed

Isaksson, Mathias, Knapik, Lukas January 2010 (has links)
The task for this thesis was to develop, construct and evaluate a multi‐bus communication system,connected to a PC via USB and capable of communicating in CAN, I2C and SPI and develop drivers for itin National Instruments LabVIEW.In the beginning a study was made of the communication buses followed by an investigation of whattype of hardware that could accomplish this task. A microcontroller unit was selected andprogrammed in MikroElektronika MikroC Pro v.3.2 to act as the interface between the communicationbusses and PC. A PCB prototype of the system was constructed by using Eagle Cad software v.5.6.0. General drivers for this system where created in LabVIEW v.8.6.1 so the end‐user simply can createtheir own applications and control the compatible hardware depending on their type of purposes. Thesystem was tested on criteria’s such as: speed, power consumption, burst performance andtransmission length depending on which communication bus was used.
40

A smart gateway design for WSN health care system

Yaoming, Chen January 2010 (has links)
Using Wireless Sensor Networks (WSNs) in health care system has yielded a tremendous effort in recent years. However, in most of these researches tasks like sensor data processing, health states decision making and emergency messages sending are done by a remote server. Numbers of patient with large scale of sensor data consume a lot of communication resource, bring a burden to the remote server and delay the decision time and notification time. In this paper, we present a prototype of a smart gateway that we have implemented. This gateway is an interconnection and services management platform especially for WSN health care systems at home environments, by building a bridge between WSN and public communication networks, compatible with an on-board data decision system (DDS) and a lightweight database, which enable to make the patient’s health states decision in the gateway in order to get faster response time to the emergencies. We have also designed the communication protocols between WSN, gateway and remote servers. Additionally Ethernet, Wi-Fi and GSM/GPRS communication module are integrated into the smart gateway in order to report and notify information to care-givers.  We have conducted experiments on the proposed smart gateway by performing it together with a wireless home e-health care sensor network. The results show that it is reliable and has low latency and low power consumption.

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