• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 32
  • 10
  • Tagged with
  • 42
  • 8
  • 5
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 3
  • 3
  • 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.
1

Lossles Compression of ECG signals : Performance Analysis in a Wireless Network

Bayarri Portolés, Laia January 2009 (has links)
<p>With the development of multimedia and digital systems there is a need toreduce the cost of storage and transmission of information. The storage requirementsfor long signals like 24-hour heart monitoring are very large sosignal compression is often employed. The cost reduction achieved throughcompression leads to a reduction in the amount of data that represents theinformation. At the same time, once the decompression procedure is done,the resulting signal must contain enough detail for the cardiologist to be ableto identify irregularities. \Lossy"compressors may hide such details, whereas\lossless" compressor preserves the signal exactly as captured.</p><p>This thesis researches into the performance of several lossless compressionalgorithms widely used for image coding. The dierent compressiontechniques are evaluated not only in terms of compression ratio and compressionand decompression bandwidths achieved but also based on theirperformance when the compressed data must be sent over any of the availablewireless networks.</p><p>This thesis documents the work of a master's degree project carried outduring the spring of 2009. The project is part of a research project withinthe Department of Biomedical Engineering at Linkopings Universitet. Theproject aims at researching and developing a data compression model fortransmitting medical signals. The model should be feasible and it shouldprove the advantages of data compression. These implementations are intendedto be used within a larger system allowing a patient to transmitmedical data from a remote location.</p>
2

Lossles Compression of ECG signals : Performance Analysis in a Wireless Network

Bayarri Portolés, Laia January 2009 (has links)
With the development of multimedia and digital systems there is a need toreduce the cost of storage and transmission of information. The storage requirementsfor long signals like 24-hour heart monitoring are very large sosignal compression is often employed. The cost reduction achieved throughcompression leads to a reduction in the amount of data that represents theinformation. At the same time, once the decompression procedure is done,the resulting signal must contain enough detail for the cardiologist to be ableto identify irregularities. \Lossy"compressors may hide such details, whereas\lossless" compressor preserves the signal exactly as captured. This thesis researches into the performance of several lossless compressionalgorithms widely used for image coding. The dierent compressiontechniques are evaluated not only in terms of compression ratio and compressionand decompression bandwidths achieved but also based on theirperformance when the compressed data must be sent over any of the availablewireless networks. This thesis documents the work of a master's degree project carried outduring the spring of 2009. The project is part of a research project withinthe Department of Biomedical Engineering at Linkopings Universitet. Theproject aims at researching and developing a data compression model fortransmitting medical signals. The model should be feasible and it shouldprove the advantages of data compression. These implementations are intendedto be used within a larger system allowing a patient to transmitmedical data from a remote location.
3

Benchmarking of mobile network simulator, with real network data

Näslund, Lars January 2007 (has links)
<p>In the radio network simulator used in this thesis the radio network from a specific operator is modeled. The real network model in the simulator uses, a 3-D building database, realistic site data (antenna types, feederloss, ...) and parameter setting from field. In addition traffic statistics are collected from the customer’s network for the modeled area. The traffic payload is used as input to the simulator and creates an inhomogeneous traffic distribution over the area. One of the outputs from the simulator is power per cell.</p><p>The purposes of this thesis are to identify simulation accuracy compared to reality and to evaluate and improve the simulation models and the methods used when making a simulation of a real WCDMA network with the Astrid simulator.</p><p>In cellular systems the transmitted power influences the interference in the network and the interference is in turn affecting the performance. As the transmitted RBS power influences the downlink interference, it is important that the RBS power level is accurate in the simulator. Therefore the simulated RBS power is benchmarked with the real RBS power. The traffic payload from the real network is used as input into the simulator. Based on the traffic payload the simulator generates RBS power as output. The simulated RBS power is then compared with the measured RBS power.</p><p>It has been found that the standard parameter setting in the simulator gives in average about 1 W too much RBS power used in the simulations compared to reality. After investigation it was detected that two reasons for the overestimated power are that the common control channels (CCCH) power setting and the feederloss is not set to the same values as in field. With the new CCCH settings and feederloss the simulator overestimates the RBS power with 0.5 W in average. As the traffic today is relatively low the parameters that only affect the dedicated channels can only be used to make small adjustments of the simulated RBS power.</p>
4

Benchmarking of mobile network simulator, with real network data

Näslund, Lars January 2007 (has links)
In the radio network simulator used in this thesis the radio network from a specific operator is modeled. The real network model in the simulator uses, a 3-D building database, realistic site data (antenna types, feederloss, ...) and parameter setting from field. In addition traffic statistics are collected from the customer’s network for the modeled area. The traffic payload is used as input to the simulator and creates an inhomogeneous traffic distribution over the area. One of the outputs from the simulator is power per cell. The purposes of this thesis are to identify simulation accuracy compared to reality and to evaluate and improve the simulation models and the methods used when making a simulation of a real WCDMA network with the Astrid simulator. In cellular systems the transmitted power influences the interference in the network and the interference is in turn affecting the performance. As the transmitted RBS power influences the downlink interference, it is important that the RBS power level is accurate in the simulator. Therefore the simulated RBS power is benchmarked with the real RBS power. The traffic payload from the real network is used as input into the simulator. Based on the traffic payload the simulator generates RBS power as output. The simulated RBS power is then compared with the measured RBS power. It has been found that the standard parameter setting in the simulator gives in average about 1 W too much RBS power used in the simulations compared to reality. After investigation it was detected that two reasons for the overestimated power are that the common control channels (CCCH) power setting and the feederloss is not set to the same values as in field. With the new CCCH settings and feederloss the simulator overestimates the RBS power with 0.5 W in average. As the traffic today is relatively low the parameters that only affect the dedicated channels can only be used to make small adjustments of the simulated RBS power.
5

En jämförande studie kring några av dagens produkter inom Store and Forward och Live / A comparative study of some of today's systems in video transfer and broadcasting

Thyr, Tomas, Bly, Daniel January 2008 (has links)
<p>SVT is Sweden’s largest TV-network and broadcasts more then 22 000 hours of TV each year. SVT is a public service company where the basic idea is to reflect the world from different perspectives and news is very important for providing neutral and versatile information in a variety of areas. An important part of the flow of information is to continuously receive reports from all corners of the world around the clock. This places very high demands on the technology used and it is important that it function and develops to meet current and future growing needs. One of SVTs vision is to increase the proportion of live reports in news broadcasts and self produced news reports from remote locations and is therefore interested in new technologies that offer greater topicality and lower cost for the reports. There are two different technologies used in the present situation, Store and Forward and Live. The difference between them is that at the Store and Forward the reporter sends a complete edited feature back to the news room. When doing a Live the reporter simply performs a live reporting. During the project a technical comparison between today’s products has been performed, the comparison has highlighted advantages and disadvantages of these products video and audio coding and data transmission. Even a comparison of their ease of use and functionality has been conducted and results are to be the basis for a set of requirements for additional procurement of large scale purchases of new systems. The results have shown that the system from the English company Quicklink is the one that performs best image quality overall for both Store and Forward and Live. The system has a well working interface with many smart features and is also easy to use in a large scale environment. All these features make the application from Quicklink best suited for SVTs needs.</p>
6

Positionsbestämning av radiosändare med kägelsnittsmetoden.

Hedström, Joakim January 2007 (has links)
<p>Vid Positionsbestämning av radiosändare med TDOA(Time Difference Of Arrival) är det traditionella sättet att låta varje uppmätt tidsskillnad definiera en hyperbelgren på vilken sändaren befinner sig. Skärningspunkten mellan två eller fler hyperbelgrenar ger sändarens position.</p><p>Målet med examensarbetet är att identifiera möjliga sändarpositioner och detektera mångtydigheter. Problemet har lösts med kägelsnittsmetoden som låter tre mottagares positioner och deras uppmätta tidsskillnader definiera ett kägelsnitt där sändarens position är i en av dess fokuspunkter.</p>
7

CPM for RLS system

Bergquist, Frans January 2007 (has links)
<p>The main goal of this thesis is to create a continuous phase modulated radio system with a recursive least square equalizer. The two tested channel models are typical urban and rural area. The result of the performance of this radio system is displayed in Matlab plots as the bit error rate. Three error rates are displayed; with error correction, without error correction and the rate of received incorrect message bursts. Conclusions are also drawn of the performance of the radio system in kbit/sec of bandwidth when the different channel models are used. The performance is also divided into how the equalizer handles inter symbol interference or a fading channel without inter symbol interference.</p> / <p>I detta examensarbete har ett fasmodulerat radiosystem simulerats, fokusering ligger på kanalutjämnare som är av typen recursive least square (RLS). RLS utjämnaren har testats med två olika gsm kanalmodeler, dels typical urban som simulerar radioförbindelser i stadsmiljö den andra modellen är rural area där sändare och mottagare kan se varandra. Tre olika resultat presenteras; med felrättande koder, utan felrättande koder och mängden icke korrekta datapaket. Slutsatser dras om radiosystemets bandbredd när de olika kanalmodellerna används vid olika brusmängd. Även utjämnarens förmåga att hantera inter-symbol interference och fading utvärderas också.</p>
8

En jämförande studie kring några av dagens produkter inom Store and Forward och Live / A comparative study of some of today's systems in video transfer and broadcasting

Thyr, Tomas, Bly, Daniel January 2008 (has links)
SVT is Sweden’s largest TV-network and broadcasts more then 22 000 hours of TV each year. SVT is a public service company where the basic idea is to reflect the world from different perspectives and news is very important for providing neutral and versatile information in a variety of areas. An important part of the flow of information is to continuously receive reports from all corners of the world around the clock. This places very high demands on the technology used and it is important that it function and develops to meet current and future growing needs. One of SVTs vision is to increase the proportion of live reports in news broadcasts and self produced news reports from remote locations and is therefore interested in new technologies that offer greater topicality and lower cost for the reports. There are two different technologies used in the present situation, Store and Forward and Live. The difference between them is that at the Store and Forward the reporter sends a complete edited feature back to the news room. When doing a Live the reporter simply performs a live reporting. During the project a technical comparison between today’s products has been performed, the comparison has highlighted advantages and disadvantages of these products video and audio coding and data transmission. Even a comparison of their ease of use and functionality has been conducted and results are to be the basis for a set of requirements for additional procurement of large scale purchases of new systems. The results have shown that the system from the English company Quicklink is the one that performs best image quality overall for both Store and Forward and Live. The system has a well working interface with many smart features and is also easy to use in a large scale environment. All these features make the application from Quicklink best suited for SVTs needs.
9

Positionsbestämning av radiosändare med kägelsnittsmetoden.

Hedström, Joakim January 2007 (has links)
Vid Positionsbestämning av radiosändare med TDOA(Time Difference Of Arrival) är det traditionella sättet att låta varje uppmätt tidsskillnad definiera en hyperbelgren på vilken sändaren befinner sig. Skärningspunkten mellan två eller fler hyperbelgrenar ger sändarens position. Målet med examensarbetet är att identifiera möjliga sändarpositioner och detektera mångtydigheter. Problemet har lösts med kägelsnittsmetoden som låter tre mottagares positioner och deras uppmätta tidsskillnader definiera ett kägelsnitt där sändarens position är i en av dess fokuspunkter.
10

CPM for RLS system

Bergquist, Frans January 2007 (has links)
The main goal of this thesis is to create a continuous phase modulated radio system with a recursive least square equalizer. The two tested channel models are typical urban and rural area. The result of the performance of this radio system is displayed in Matlab plots as the bit error rate. Three error rates are displayed; with error correction, without error correction and the rate of received incorrect message bursts. Conclusions are also drawn of the performance of the radio system in kbit/sec of bandwidth when the different channel models are used. The performance is also divided into how the equalizer handles inter symbol interference or a fading channel without inter symbol interference. / I detta examensarbete har ett fasmodulerat radiosystem simulerats, fokusering ligger på kanalutjämnare som är av typen recursive least square (RLS). RLS utjämnaren har testats med två olika gsm kanalmodeler, dels typical urban som simulerar radioförbindelser i stadsmiljö den andra modellen är rural area där sändare och mottagare kan se varandra. Tre olika resultat presenteras; med felrättande koder, utan felrättande koder och mängden icke korrekta datapaket. Slutsatser dras om radiosystemets bandbredd när de olika kanalmodellerna används vid olika brusmängd. Även utjämnarens förmåga att hantera inter-symbol interference och fading utvärderas också.

Page generated in 0.0857 seconds