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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.
1

Analys och utvärdering av LED-belysning i Stockholms tunnelbana / Analysis and evaluation of LED lighting in the subway of Stockholm

Alfrijat, Christopher, Eriksson, Rasmus January 2019 (has links)
Trafikförvaltningen, som ansvarar för kollektivtrafiken i Stockholm, har startat ett projekt för att byta ut befintliga armaturer i Stockholms tunnelbana mot LED-armaturer. Denna rapport utför förarbetet inför en kommande upphandling. Detta arbete utvärderar olika LED-armaturers tekniska specifikationer som är lämpliga för Stockholms tunnelbana där armaturerna ska bytas ut. För denna miljö saknas det i dagsläget standarder som är anpassade för LED-armaturer. Med hjälp av litteraturstudier och mätningar kunde underlag för en kravspecifikation skapas. Mätningar har gjorts på ett urval av LED-armaturer och deras tekniska specifikation har presenterats. Samtliga armaturer klarade EMC-testerna (elektromagnetisk kompabilitet) där inga störningar uppstod vid frekvenserna för Storstockholms Lokaltrafiks (SL) radiokommunikationssystem. Arbetet har även hanterat miljö- samt den ekonomiska aspekten av implementeringen av LED-belysning. / Trafikförvaltningen, responsible for public transport in Stockholm, has started a project to replace existing luminaires in the subway of Stockholm to LED lights. This thesis could be a basis for an upcoming procurement. In this report, various models of LED lights technical specifications will be evaluated based on the environmental requirements in Stockholm’s subway, where the existing luminaires will be replaced. For this environment, there is no standard regarding LED lights today. With the help of literature studies and tests, a groundwork for a specification could be made. The tests were only made on a selection of LED lights and their technical specifications were presented. All luminaires passed the EMC (electromagnetic compatibility) tests that were made in order to determine any interference with Stockholm’s public transport (SL) radio communication system. Environmental aspects and economical aspects of the implementation of LED lights has been taken into consideration.
2

Sidokanalattack mot knappsats för elektroniskt passersystem / Side-channel attack against electronic entry system keypad

Alasjö, Alexander January 2017 (has links)
Genom ett undersökande experiment med elektromagnetisk sidokanalattack mot en knappsats för ett kommersiellt passersystem påvisas att informationsläckage i sidokanaler är ett fortsatt aktuellt problem och hur det gör fysisk åtkomstkontroll sårbart genom avlyssning och kopiering av användaruppgifter. Med enkel radioutrustning kan knapptryckningar registreras och avkodas genom oönskad elektromagnetisk strålning och teoretiskt är det möjligt att genomföra avlyssningen på en längre distans med särskilt utformad antenn och anpassad mottagare. Rapporten diskuterar problematiken med emission security hos konsumentprodukter som i militära sammanhang benämns Tempest eller RÖS (röjande signaler) och kräver kostsamma tester för att detekteras och hanteras. I regelverk för EMC (elektromagnetisk kompatibilitet) behandlas elektriska apparaters och näts utstrålning och påverkan av elektromagnetiska vågor, men inte direkt hur information kan läcka från informationsteknologisk utrustning vilket denna rapport vill problematisera. / Through an exploratory experiment using electromagnetic side-channel attack against a keypad for a commercial entry system it is demonstrated that information leakage through side-channels are an ongoing issue and may make entry systems vulnerable by recording of user data. Using simple radio equipment, keypresses can be recorded and decoded by undesired electromagnetic radiation and theoretically it is possible to carry out the attack on a longer distance with a specially designed antenna and a custom recieiver. The report discusses emission security in consumer products which in military context is termed Tempest or compromising emanations (Swedish: RÖS) and requires expensive tests to be detected and handled. The EMC regulations (electromagnetic compatibility) handles radiation and influence of electromagnetic waves in electronic apparatus and nets, but not directly how information can leak from information technology equipment which this report wants to problematize.
3

Development of a Novel Method for Automotive On-board Transmitter EMC Immunity Testing / Utveckling av en Immunitetsmetod för Elektromagnetisk Kompatibilitetstestning vid Simulering av Strålningskälla i Fordon

Holm, Ludvig January 2023 (has links)
As the automotive industry advances through technology integration, components are designed to operate at increasingly higher frequencies. Consequently, there will be an increasing demand for automotive electromagnetic compatibility (EMC) testing. Testing and certification institutes, such as RISE Research Institutes of Sweden AB, thus face an urgent need to develop innovative solutions that can effectively address this growing demand. This master thesis work concerns one EMC test method in particular - the On-board Transmitter (OBT). This is a test which mainly serves to test the immunity of vehicles to electromagnetic disturbances originating from hand-held devices. The conventional test is performed in an anechoic chamber and the methodology requires a substantial amount of time. The intent with this work is thus to evaluate the potential of a novel OBT method where the concept of a reverberating chamber is applied inside the vehicle compartment. Initially, the conventional method was examined from two mock-ups of idealized cases, and it was observed that the electromagnetic field in the near-field region of the transmitter is highly erratic. It was also concluded that the test setup is particularly sensitive to the polarization of the transmitter. With these findings in mind, the accuracy of the conventional method was deemed questionable. Evaluation of the proposed Reverberating On-board Transmitter (ROBT) method proved that the electromagnetic environment inside the vehicle did not resemble a perfect reverberation chamber. Which was expected as the absorbing material such as seating and upholstery likely prevents a field distribution similar to that in a reverberation chamber. Still, the intent of the project was to find a test method superior to the conventional method and it can be stated that the ROBT method is an adequate option due to its capacity to expose the electronics to isotropic radiation. This was found from two measures which this thesis introduces: expected isotropicity eiso, a relative measure of the electric field components and DDoF, a quantification of the spatial distribution inside a reverberation chamber. / EMC VERifiering av Autonoma fordon i modväxlad kammare (EMCVERA)

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