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605 Uppsatser om Signalöverföring - Sida 18 av 41
Undersökning av modulationsscheman för existerande bredbandsteknologier
In this thesis some different modulation schemes for xDSL-techniques are compared. The investigated techniques are ADSL, G.lite, ADSL2, HDSL, SHDSL and VDSL. The modulation methods used are DMT, CAP and different versions of PAM. Several broadband techniques also use Trellis Coded Modulation (TCM) to increase the coding gain of the transmission. For each one of the different modulation methods the signal-to-noise ratio is calculated for generating a bit error rate probability of 10-7.
Mätning av axiella magnetiska läckflöden i vattenkraftsgeneratorer
This thesis describes a method of measuring axial magnetic leakage flux in an operational hydropower generator. Axial magnetic leakage flux is the magnetic flux at the ends of a rotating generator, which goes through the stator parallel to the rotor axis. This flux can cause circulating currents in the stator iron, giving rise to losses, and can in the worst case overheat a generator, causing it to melt down. To measure the axial flux, and how it affects the generator temperature, a measurement system was constructed on behalf of Vattenfall. The system consists of search coil sensors and a signal-processing unit with amplifiers and active filtering. To confirm the behaviour of the axial leakage flux and the functionality of the measurement system, a test installation was made.
Optimering av informationsinsamlingvid prototyptillverkning
This report discusses a method to detect divers in harbour environments usingpassive acoustic detection. The goal was to achieve as high detection as possiblewithout having too high false alarm rate. A short execution time was also desirable.By using the characteristic of an inhalation a band-pass filter was applied to the signalto improve the signal to noise ratio. After the filtering an energy estimation of thesignal was made. This energy estimation was later used in a frequency analysis, whichcould tell us if there were enough energy in the frequencies that correspond to adivers breathing frequency.
Förbränningslära för bubblandefluidbädd
Radio Frequency Identification, RFID, is a convenient way to enable contactless identification which does not require any physical nor optical contact. As with any radio-based communication the signal can be intercepted, thus making the technology vulnerable to several kinds of attacks. Interception of communication is not the only threat. Since RFID tags might contain personal information or information that will grant the owner access to secure areas, skimming and spoofing attacks are also major threats against this technology. In this thesis report, the perspective of an adversary is portrayed in an RFID-enabled environment by presenting where RFID is used and how it could be abused.
Praktisk optimering av marknadsföring i sociala medier
Detta arbete undersöker hur företagare praktiskt kan optimera sina marknadsföringssatsningar i sociala medier. Marknadsföring i sociala medier är något som många företagsledare prioriterar eftersom det främjar en tvåvägskommunikation som i sin tur kan leda till att man når ut till fler kunder och ge lyckade vinsteffekter.Arbetet behandlar utvalda best-practices för att hitta de rekommendationer som kan ses som bäst lämpade för att praktiskt optimera ett företags webbsida och profilsidor i sociala medier. För att precisera rekommendationerna granskade arbetet vilka som tillämpas i verkligheten samt vilket behov och vilken kunskap mindre verksamheter har av sociala medier. Detta undersöktes genom att analysera fem företags aktivitet på Internet samt genomföra en enkätundersökning riktad till småföretagare. Resultatet omfattar en sammanställning över adekvata rekommendationer till mindre företag som praktiskt vill optimera sina marknadsföringssatsningar i sociala medier..
Att v?lja den vinnande sponsringen - f?r b?de f?retag och samh?lle. Hur sponsorer v?ljer elitklubbar att sponsra samt hur de m?ter effekterna
Sponsring har blivit en av de vanligaste marknadsf?ringsmetoderna och forts?tter att v?xa i
popularitet. Sponsring inneb?r att ett f?retag k?per r?tten att associera sig med en r?ttighet,
till exempel en idrottsklubb. Anledningen till dess popularitet kan ha att g?ra med dess
varum?rkesbyggande egenskaper.
Signalanalys med ATLAS
On Ericsson Ltd in Borås a wireless communication system called MINI-LINK? is produced. In order to sell their product with the best possible quality guaranty, there is a signal processing circuit called ATLAS implemented in the system. This circuit would eventually be useful in the production and for the repairs of the radio units. Our commission was to examine the possibility for this use.
Windbelt
Radio Frequency Identification, RFID, is a convenient way to enable contactless identification which does not require any physical nor optical contact. As with any radio-based communication the signal can be intercepted, thus making the technology vulnerable to several kinds of attacks. Interception of communication is not the only threat. Since RFID tags might contain personal information or information that will grant the owner access to secure areas, skimming and spoofing attacks are also major threats against this technology. In this thesis report, the perspective of an adversary is portrayed in an RFID-enabled environment by presenting where RFID is used and how it could be abused.
Varumärket till er tjänst : Varuma?rkets roll i den va?rdeskapande processen utifra?n ett tja?nstelogiskt perspektiv
Enligt det tja?nstelogiska synsa?ttet blir upplevelsen kring ett ko?p allt viktigare. Samtidigt a?r varuma?rket en viktig resurs i marknadsfo?ringsteori idag. Det saknas dock ett tydligt resonemang fo?r hur varuma?rket passar in i interaktionen mellan fo?retag och konsument.
Analys av säkerheten av RFID i inpasseringssystem
Radio Frequency Identification, RFID, is a convenient way to enable contactless identification which does not require any physical nor optical contact. As with any radio-based communication the signal can be intercepted, thus making the technology vulnerable to several kinds of attacks. Interception of communication is not the only threat. Since RFID tags might contain personal information or information that will grant the owner access to secure areas, skimming and spoofing attacks are also major threats against this technology. In this thesis report, the perspective of an adversary is portrayed in an RFID-enabled environment by presenting where RFID is used and how it could be abused.
Passive acoustic diver detection
This report discusses a method to detect divers in harbour environments usingpassive acoustic detection. The goal was to achieve as high detection as possiblewithout having too high false alarm rate. A short execution time was also desirable.By using the characteristic of an inhalation a band-pass filter was applied to the signalto improve the signal to noise ratio. After the filtering an energy estimation of thesignal was made. This energy estimation was later used in a frequency analysis, whichcould tell us if there were enough energy in the frequencies that correspond to adivers breathing frequency.
Testprogram till hårdvara på en viktindikator
Radio Frequency Identification, RFID, is a convenient way to enable contactless identification which does not require any physical nor optical contact. As with any radio-based communication the signal can be intercepted, thus making the technology vulnerable to several kinds of attacks. Interception of communication is not the only threat. Since RFID tags might contain personal information or information that will grant the owner access to secure areas, skimming and spoofing attacks are also major threats against this technology. In this thesis report, the perspective of an adversary is portrayed in an RFID-enabled environment by presenting where RFID is used and how it could be abused.
Adaptiv temperaturreglering av bostadshus
The control of indoor temperature must be able to handle large time constants and both measureable disturbances like outdoor temperature, and non-measurable disturbances, like waste heat from appliances. Due to cheaper microcontrollers (small computers with designated tasks) with better performance, more advanced and computation-demanding methods for control can be used.In this thesis, Generalized Predictive Control (GPC) has been implemented and tested on a theoretically derived model of a house. GPC states that a model of the system is estimated in every sample, and the control is carried out simultaneously, based on predictions of the model. Disturbances like solar radiation can be estimated and used in the control as well. The control signals are determined by quadratic programming, which makes it possible to consider conditions, for example limitations on the control signals.GPC requires a number of parameters to be defined, like model order and control signal penalty, but is relatively robust for variations in them.
Inlösen eller extrautdelning?: En studie av sambandet mellan valet av kapitalåterföringsmetod och värdeskapande för aktieägarna
This thesis studies the stock price reaction around 68 announcements of special dividends and share redemptions on the Swedish stock market between the years of 2003 and 2007. We show that for the Swedish private investor, the tax effect of a share redemption is lower than that of a special dividend. Moreover, a share redemption could be interpreted as a signal of undervaluation. These two factors lead us to assume that the stock market would react more positively in connection to the announcement of a share redemption. We test this hypothesis through an analysis of the risk-adjusted abnormal return for the observations in the sample.
Externhandelns konsekvenser för cityhandeln, i skenet av en ny trafikled : En studie om Söderslättetableringens och Umeåprojektets betydelse förhandeln i Umeå
The purpose of this study is to highlight how a ring road and an external retail establishment may affect the city commerce. Umeå is the study object with interesting undergoing changes including a new external retail area south of the city and a new transport route that will lead the through traffic around the city.The study is based on a review of previous studies and a qualitative method. Four interviews were conducted with people who have a connection to commerce and/or municipal planning and where considered able to contribute with rich and relevant information. The result shows that the commerce in Umeå will be significantly strengthened in the context of a new external commercial establishment when the city?s overall attractiveness increases.