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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.
271

Vision Sensor Scheduling for Multiple Target Tracking / Schemaläggning av bildsensorer för följning av multipla mål

Hagfalk, Erik, Eriksson Ianke, Erik January 2010 (has links)
This thesis considers the problem of tracking multiple static or moving targets with one single pan/tilt-camera with a limited field of view. The objective is to minimize both the time needed to pan and tilt the camera's view between the targets and the total position uncertainty of all targets. To solve this problem, several planning methods have been developed and evaluated by Monte Carlo simulations and real world experiments. If the targets are moving and their true positions are unknown, both their current and future positions need to be estimated in order to calculate the best sensor trajectory. When dealing with static and known targets the problem is reduced to a deterministic optimization problem. The planners have been tested through experiments using a real camera mounted above a car track using toy cars as targets. An algorithm has been developed to detect the cars and associate the detections with the correct target. The Monte Carlo simulations show that, in the case of static targets, there is a huge advantage to arrange the targets into groups to be able to view more than one target at the time. In the case of moving targets with estimated positions it can be concluded that if the objective is to minimize the error in the position estimation the best planning choice is to always move to the target with the highest position uncertainty.
272

Implementing RF Masurement System :SNA / Implementing RF Masurement System :SNA

WANG, LEI January 2010 (has links)
The thesis purpose is to be implementing a system where a sweeping signal generator connected to a scalar network analyzer (SNA). The SNA is a less complicated that the VNA and normally much cheaper. Between these two instruments only the cable fro synchronization between then needed. The synchronization signal is simply low frequency saw tooth signal not so sensitive for disturbance as RF signal. Therefore a very simple cable can be used.
273

High Level Model of IEEE 802.15.3c Standard and Implementation of a Suitable FFT on ASIC

Ahmed, Tanvir January 2011 (has links)
A high level model of HSIPHY mode of IEEE 802.15.3c standard has been constructedin Matlab to optimize the wordlength to achieve a specific bit error rate (BER) depending on the application, and later an FFT has been implemented for different wordlengths depending on the applications. The hardware cost and power is proportional to wordlength. However, the main objective of this thesis has been to implement a low power, low area cost FFT for this standard. For that the whole system has been modeled in Matlab and the signal to noise ratio (SNR) and wordlength of the system have been studied to achieve an acceptable BER. Later an FFT has been implemented on 65nm ASIC for a wordlength of 8, 12 and 16 bits. For the implementation, a Radix-8 algorithm with eight parallel samples has been adopted. That reduce the area and the power consumption significantly compared to other algorithms and architectures. Moreover, a simple control has been used for this implementation. Voltage scaling has been done to reduce thepower. The EDA synthesis result shows that for 16bit wordlength, the FFT has 2.64 GS/s throughput, it takes 1.439 mm2 area on the chip and consume 61.51mW power.
274

UKF and EKF with time dependent measurement and model uncertainties for state estimation in heavy duty diesel engines

Berggren, Henrik, Melin, Martin January 2011 (has links)
The continuous challenge to decrease emissions, sensor costs and fuel consumption in diesel engines is battled in this thesis. To reach higher goals in engine efficiency and environmental sustainability the prediction of engine states is essential due to their importance in engine control and diagnosis. Model output will be improved with help from sensors, advanced mathematics and non linear Kalman filtering. The task consist of constructing non linear Kalman Filters and to adaptively weight measurements against model output to increase estimation accuracy. This thesis shows an approach of how to improve estimates by nonlinear Kalman filtering and how to achieve additional information that can be used to acquire better accuracy when a sensor fails or to replace existing sensors. The best performing Kalman filter shows a decrease of the Root Mean Square Error of 75 % in comparison to model output.
275

Real-time monitoring of voice characteristics usingaccelerometer and microphone measurements

Virebrand, Marcus January 2011 (has links)
VoxLog is a portable voice accumulator, that uses both an accelerometer that measures skin vibrations and a regular microphone to collect data. The goal of the thesis was to implement and evaluate methods that based on this data estimate the three different voice parameters fundamental frequency, phonation and soundpressure level. For pitch, three different methods were evaluated. The different methods all require relatively low computational power since the goal was to implement at least one of them on the digital signal processor in the VoxLog. The results from these evaluations show that the best estimations of pitch were made with a FFT-based approach that uses phase information to get an estimation with high frequencyresolution. Phonation is estimated with an energy based voice activity detection method.This estimation is then used to choose when sound pressure level should be estimated. Here one of the main problems was to make a distinction between when sound pressure level should be estimated for the wearer of the VoxLog or when an estimation should be made for the background noise. This was solved by implementing a time window before and after phonation were neither is estimated. For both pitch and sound pressure level a feedback functionality was implemented. The feedback is given to the user via vibrations in the VoxLog, the feedback is given when estimated parameters break set limits on pitch or sound pressure level.
276

A Control System for Battery Charging in Buses

Kjelldal, Therese January 2011 (has links)
A common configuration in buses is that the engine is placed in the rear of the bus and that the batteries are placed in thefront of the bus due to optimization of the distribution of the weight. The long wires running between the engine and the batteries together with large power consuming units, such as fans and air condition units, result in voltage drops. The voltage drops contribute to the battery charging voltage level being lower than desired. The aim with this thesis work is to implement a control system that increases the battery voltage level when the voltage drops occur. Measurements are performed on an articulated bus that is in focus throughout the whole thesis work. A model for the electrical circuit of the bus is created and used when investigating the stability of the control system. The control system isimplemented in the bus, where also verification tests are performed. The verification tests confirm that the control system raises the battery charging voltage to the desired level. The increased voltage level makes the batteries reach a higher state of charge in shorter time since the control system provides the batteries with more charge.
277

Design of Ultra Low Power Transmitter for Wireless medical Application.

Srivastava, Amit January 2009 (has links)
Significant advanced development in the field of communication has led many designers and healthcare professionals to look towards wireless communication for the treatment of dreadful diseases. Implant medical device offers many benefits, but design of implantable device at very low power combines with high data rate is still a challenge. However, this device does not rely on external source of power. So, it is important to conserve every joule of energy to maximize the lifetime of a device. Choice of modulation technique, frequency band and data rate can be analyzed to maximize battery life. In this thesis work, system level design of FSK and QPSK transmitter is presented. The proposed transmitter is based on direct conversion to RF architecture, which is known for low power application. Both the transmitters are designed and compared in terms of their performance and efficiency. The simulation results show the BER and constellation plots for both FSK and QPSK transmitter.
278

Sending and Receiving Data between Mobile and Data Logger

Abbaraju, Nanda January 2008 (has links)
No description available.
279

A Pre-study in Programmable Logic for use in fast Trigger Based Data Communication

Almfors, Johan January 2005 (has links)
This Bachelor thesis is a pre-study of the possibilities of using programmable logic in the purpose to enable fast trigger based data communication. Triggerbased data communication is in this case referred to a context where the processed data is stored and examined so when the trig situation appears the data should be able read out to a computer for evaluating. The purpose of this thesis is to find difficult and time consuming elements but also to find elements that is well suited for implementation in programmable logic. The work should also support further development and verification of trig functionalities and additional hardware. This with the intent of constructing an Ethernet based oscilloscope. The result of this thesis is a conclusion that programmable logic is well suited for many of the implemented logic function
280

Sensorsystem till hinderhanterande robot / Sensor System for Obstacle Handling Robot

Lichtermann, Johan January 2005 (has links)
The projects goal is to construct and program a robot that is controlled from a computer but also have an obstacle handling function that allows the robot to navigate around the object by itself. The robot is a simple construction and the number of components and functions is kept at a minimum. A tricycle construction was chosen because it’s the simplest. Communication between the robot and the computer also kept as simple as possible. / Målet med projektet är att konstruera och programmera en robot som går att styra från en dator men det skall även finnas en hinderhanterande funktion som gör att roboten kan åka runt hinder av sig själv. Roboten är en enkel konstruktion där antalet komponenter och funktioner hålls nere till ett minimum. En trehjuling valdes då det är den enklaste konstruktionen. Kommunikationen mellan roboten och datorn hålls också så enkel som möjligt.

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