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Studie av reaktivt effektGustafsson, Daniel January 2015 (has links)
Den här rapporten är en analys av reaktiv effektförbrukning från två anläggningar i Karlstad, Heden och en nätstation som kallas T375. Med rapporten vill jag skapa en bättre förståelse för hur den reaktiva effektförbrukningen ser ut i elnätet och hur den påverkar kunden. Varje negativ reaktiv effekt ska kontrolleras och med hjälp av värdena ska den mest lämpade åtgärden tas fram. Karlstads Elnät AB, som har ansvar för företaget Heden och nätstation T375, samlar in sina värden från anläggningar en gång om dagen och värdena kontrolleras under natten. Värdena från nätstation T375 som använts under den här rapporten är från år 2000. Hedens värden är från år 2014. Värdena har analyserats med hjälp av kalkylprogrammet Microsoft Excel.Värdena har analyserats utifrån energiförbrukning och effektfaktor samt max-, min- och medelvärden. Det har skapats grafer över den reaktiva och den aktiva energiförbrukningen samt effektfaktorn under en viss tidsperiod. Resultatet kommer från analysering av effektförbrukningen och effektfaktorn från båda anläggningarna samt teoretiska åtgärder för att motverka den kapacitiva reaktiva effektförbrukningen har tagits fram.
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Jitter Management in Circuit Switched Voice over HSPA NetworksSong, Ge January 2009 (has links)
<p>When a shared channel or packet switched network is used for transmission (e.g.WLAN, HSPA (Turbo-3G), LTE (4G)), it introduces variance in the delay of packets. Thisvariance is called jitter. This jitter can lead to significant degradation of quality inreal-time services if it is not properly handled.</p><p>High Speed Packet Access (HSPA) is an extension to the third Generation W-CDMAcellular network that provides significantly increased bandwidth and network capacity byintroducing a High Speed-Downlink Shared Channel (HS-DSCH) for downlink and anEnhanced-Dedicated Channel (E-DCH) for uplink. Both HS-DSCH and E-DCH usere-transmissions in order to ensure a low block error rate, as a result jitter is induced inboth channels. Moreover, HS-DSCH also uses channel dependent scheduling betweenusers adding additional jitter.</p><p>Since HSPA uses IP and the voice service is provided by voice over IP (VoIP), jittermanagement is performed at the destination end-point. However, 3GPP has also specifiedtransportation of circuit switched voice over HSPA (CSoHS), where jitter managementneeds to be performed separately, at both the entry point to the core network and in thereceiving end-point as jitter is introduced both in the uplink and downlink.</p><p>This report studies CSoHS, with a focus on its delay and jitter characteristics. Itintroduces two schemes for jitter management: a fixed jitter buffer and an adaptive jitterbuffer. These jitter buffer designs are evaluated mainly by looking at the jitter loss (i.e.,the proportion of packets that have to be discarded because they exceed the maximumpermitted jitter) and the buffering time. The results show that the adaptive jitter buffer canachieve better performance in balancing the trade-off between jitter loss and bufferingdelay when dealing with various network conditions. In contrast, the fix jitter buffer is notcapable of tracking variations in the network conditions, as the performance of the fixedjitter buffer is determined solely by the configuration of the initial buffer level. Theadaptive jitter buffer is able to consistently provide equal or better quality of service thanthe fixed jitter buffer.i</p>
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Protocol Design for Control Applications using Wireless Sensor NetworksPark, Pangun January 2009 (has links)
<p>Given the potential benefits offered by wireless sensor networks(WSNs), they are becoming an appealing technology for process,manufacturing, and industrial control applications. In thisthesis, we propose a novel approach to WSN protocol design forcontrol applications. The protocols are designed to minimize theenergy consumption of the network, while meeting reliability andpacket delay requirements. The parameters of the protocol areselected by solving a constrained optimization problem, where theobjective is to minimize the energy consumption and theconstraints are the probability of successful packet reception andthe communication delay. The proposed design methodology allowsone to perform a systematic tradeoff between the controlrequirements of the application and the network energyconsumption. An important step in the design process is thedevelopment of analytical expressions of the performanceindicators. We apply the proposed approach to optimize the networkfor various communication protocols.</p><p>In Paper A, we present an adaptive IEEE 802.15.4 for energyefficient, reliable, and low latency packet transmission. Thebackoff mechanisms and retry limits of the standard are adapted tothe estimated channel conditions. Numerical results show that theproposed protocol enhancement is efficient and ensures a longerlifetime of the network under different conditions. Furthermore,we investigate the robustness and sensitivity of the protocol topossible errors during the estimation process.</p><p> </p><p>In Paper B, we investigate the design and optimization ofduty-cycled WSNs with preamble sampling over IEEE 802.15.4. Theanalytical expressions of performance indicators are developed andused to optimize the duty-cycle of the nodes to minimize energyconsumption while ensuring low latency and reliable packettransmissions. The optimization results in a significant reductionof the energy consumption compared to existing solutions.</p><p>The cross-layer protocol called Breath is proposed in Paper C. Theprotocol is suitable for control applications by using theconstrained optimization framework proposed in the thesis. It isbased on randomized routing, CSMA/CA MAC, and duty-cycling. Theprotocol is implemented and experimentally evaluated on a testbed,and it is compared with a standard IEEE 802.15.4 solution. Breathexhibits a good distribution of the work load among the networknodes, and ensures a long network lifetime.</p><p> </p><p> </p>
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The network performance assessment modelGammelgård, Magnus January 2004 (has links)
<p>The electricity distribution in Sweden is experiencing aconsiderable change in conditions by the radical change inregulation policy. The Swedish Energy Agency(Energimyndigheten) is introducing a new regulatory model, theNetwork Performance Assessment Model, as the main tool forsupervising the natural monopolies of local electricitydistribution. The new model has interesting and far-reachingconsequences for the involved parties.</p><p>This thesis investigates the implications of the newregulation and the regulatory tool, in particularly related toIT-investments evaluations in the distribution utilities. Intodays utilities, IT-systems are often a vital part ofoperations, ranging from e.g. real-time monitoring andcontrolling of the network to various administrative tasks.Considerable amounts of money are spent on investments toenhance and maintain these IT-systems. The changed regulationand the new regulatory model put a focus, more than ever, onefficient use of utilitiesresources, implying a need forsuitable methods to evaluate ITinvestments.</p><p>In the thesis, the new regulation is described, inparticular the new regulatory model. The model is presented andcentral implications are identified, e.g. in terms of newrequirements put on the utilities and general businessconsequences. As stated, the focus is on implications relatedto IT-systems and investments in these systems.</p><p>Furthermore, a wide range of IT-investment evaluationmethods are presented and categorized in the thesis, focusingon IT-investment appraisal techniques. The categories rangesfrom methods only considering cash flows of investments to moreelaborate methods, e.g. for considering behavioral sciencesaspects. The thesis outlines and presents categories of methodsas well as examples of individual methods.</p><p>In the final part of the thesis, suitable IT-investmentevaluation methods, given the implications of the newregulation, are discussed. The implications include both directbusiness related aspects as well as more technical issuesrelated to the IT-investments. It is also concluded that asuitable method need to incorporate both monetary consequencesof the investment as well as a limited number of non-monetary,related to the regulatory model.</p><p><strong>Key words:</strong>Regulation of electricity distribution,IT-investment evaluation methods, Implications of monopolyregulation</p> / QC 20100608
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Contributions to Flexible Multirate Digital Signal Processing StructuresEghbali, Amir January 2009 (has links)
<p>A current focus among communication engineers is to design flexible radio systems in order to handle services among different telecommunication standards. Efficient support of dynamic interactive communication systems requires flexible and cost-efficient radio systems. Thus, low-cost multimode terminals will be crucial building blocks for future generations of multimode communication systems. Here, different bandwidths, from different telecommunication standards, must be supported and, thus, there is a need for a system which can handle a number of different bandwidths. This can be done using multimode transmultiplexers (TMUXs) which make it possible for different users to share a common channel in a time-varying manner. These TMUXs allow bandwidth-on-demand so that the resulting communication system has a dynamic allocation of bandwidth to users. Each user occupies a specific portion of the channel where the location and width of this portion may vary with time.</p><p>Another focus among communication engineers is to provide various wideband services accessible to everybody everywhere. Here, satellites with high-gain spot beam antennas, on-board signal processing, and switching will be a major complementary part of future digital communication systems. Satellites provide a global coverage and if a satellite is in orbit, customers only need to install a satellite terminal and subscribe to the service. Efficient utilization of the available limited frequency spectrum, by these satellites, calls for on-board signal processing to perform flexible frequency-band reallocation (FFBR).</p><p>Considering these two focuses in one integrated system where the TMUXs operate on-ground and FFBR networks operate on-board, one can conclude that successful design of dynamic communication systems requires high levels of flexibility in digital signal processing structures. In other words, there is a need for flexible digital signal processing structures that can support different telecommunication scenarios and standards. This flexibility (or reconfigurability) must not impose restrictions on the hardware and, ideally, it must come at the expense of simple software modifications. In other words, the system is based on a hardware platform and its parameters can easily be modified without the need for hardware changes.</p><p>This thesis aims to outline flexible TMUX and FFBR structures which can allow dynamic communication scenarios with simple software reconfigurations on the same hardware platform. In both structures, the system parameters are determined in advance. For these parameters, the required filter design problems are solved only once. Dynamic communications, with users having different time-varying bandwidths, are then supported by adjusting some multipliers of the proposed multimode TMUXs and a simple software programming in the channel switch of the FFBR network. These do not require any hardware changes and can be performed online. However, the filter design problem is solved only once and offline.</p>
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LaserprojektorLarsson, Jon January 2010 (has links)
<p>This report describes a thesis project on 15hp. The purpose of the thesis project is to build a laser projector that reacts on sound waves and thus get a laser beam to draw visualizations of sound waves on a wall. The idea was that the design would be independent and not have to be plugged into any audio equipment. This was achieved by absorbing sound waves into a microphone. Another factor was to get a “do it yourself” -feeling of the design and therefore it was chosen to be constructed using for example, old hard-drives.</p><p>The result was a relatively large and bulky designed laser projector that can draw sound waves on a wall.</p>
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Avfyrnings-/relälådaKarlsson, Tobias, Linnér, Jakob January 2009 (has links)
<p>This is a report of our examination project in electronics carried out for Bofors Test Center in Karlskoga. The task was to construct an electronic devise for starting up different kinds of measuring systems in exact time during test sequences. The modules that are used today are old and unreliable. Our goal was to construct a prototype, which later on is supposed to be developed into a useful system.</p>
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UTVECKLING AV EN KONDENSATORMIKROFON / DEVELOPMENT OF A CONDENSER MICROPHONENordehammar, Karl-Oskar, Bergquist, Per January 2009 (has links)
<p>Detta examensarbete har utförts på Örebro universitet och Västerdalarnas Mekaniska Industri AB (VMI) i Malung för Ehrlund Microphones.Ehrlund Microphones tillverkar mikrofoner med sin patenterade kapsel, som bland annat består utav ett triangulärt membran.</p><p>Under examensarbetets tid var en ny mikrofonmodell under utveckling. Målet med examensarbetet var att bistå Ehrlund Microphones med utförandet av tester och mätningar, samt att komma med förslag till förbättringar på den nya konstruktionen.</p><p>På VMI i Malung, där kapslarna tillverkas, finns ett mätlabb som är till för att mäta kapslarnas frekvenssvar. Mätutrustningen i detta labb har installerats och konfigurerats för den mätmetod som har tagits fram för att verifiera kapslarnas frekvensgång.</p><p>Slutsatsen av undersökningen huruvida skyddsgallret påverkar mikrofonens frekvensgång, är att den volym luft som ryms innanför skyddsgallret har större betydelse för frekvensgången än vad den geometriska utformningen av gallret har.</p><p>Med stor sannolikhet kommer den nya transistorbaserade mikrofonmodellen att ha ett bättre signal/brus-förhållande än vad som visas i detta arbete, eftersom testerna har utförts på en prototyp i utvecklingsskedet.</p> / <p>This degree thesis has been conducted at the University of Örebro and Västerdalarnas Mekaniska Industri AB (VMI) in Malung on behalf of Ehrlund Microphones. Ehrlund Microphones produce microphones with their patented capsule, containing a triangular membrane.During the course of this thesis, a new microphone model was under construction. The aim was to assist Ehrlund Microphones conducting tests, measurements and also coming up with ideas of how to improve the construction of the new microphone model.</p><p>At VMI, where the capsules are produced, there is a lab designed to measure the frequency response of the capsules. The equipment in this lab has been installed and configured for the measurement method used, to verify the frequency response of the capsules.</p><p>The conclusion of the examination whether the grille of the microphone influence the frequency response of the microphone in a noticeable way, is that the volume of air enclosed by the grille has greater influence on the frequency response than the shape of the grille.</p><p>It’s most likely that the new transistor based microphone model will have an improved signal/noise-ratio, considering that the tests conducted in this essay were made on a prototype under development.</p>
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Uppbyggnad av ett fordons kompletta elsystemSjölund, Göran, Petersson, Stefan January 2002 (has links)
No description available.
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RF-modul / RF-ModuleJönsson, Kristin January 2006 (has links)
<p>Idén med examensarbetet var att konstruera en generell radiolänk med minsta möjliga storlek, som skulle kopplas samman med en redan befintlig konstruktion. Radiokrets CC1100 från Chipcon används tillsammans med mikroprocessor MSP430 från Texas Instruments. För att</p><p>radiomodulen skall klara ett stort inspänningsområde används en spänningsstabilisator XC6202 från Torex. Det färdiga kortet är ett fyralagerskort med komponenter på en sida, med ett helt jordplan. Komponenterna är placerade så att de fyller sin funktion, samtidigt som de upptar minsta möjliga utrymme egentligen kanske detta med ska vara dåtid? . Med hjälp av en nätverksanalysator undersöktes antennanpassningen så att denna erhöll ett värde på nära 50</p><p>W. Radiokretsen programmerades och testades sedan.</p> / <p>The idea behind this project was to construct a general RF-module as small as possible and the RF-module should be able to connect to an existing design. A transceiver from Chipcon, CC1100, was used together with a microprocessor MSP430 from Texas Instruments. To make</p><p>the RF-module handle a wide input voltage range a voltage regulator, XC6202, from Torex was used. The circuit board is a four layer card with one layer ground and components on one side. The components are placed to full fill there purpose and at the same time make the card</p><p>as small as possible. With help from a network analyzer the network to the antenna was examined so it obtained a value near 50 W. The RF-module was programmed and tested with good result, but I didn’t participated.</p>
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