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585 Uppsatser om Signal transmission - Sida 5 av 39
Zoonotic respiratory infections and great ape conservation - an emerging challenge
The conservation of great apes faces many challenges, one of which is the threat of infectious disease outbreaks. Zoonotic transmission of respiratory diseases from humans to wild great apes has recently been confirmed. Since respiratory disease is one of the major causes of
death in both gorillas and chimpanzees, this gives reason for major concern.
Little is known about the risks of disease transmission from humans to great apes in natural environments, and there is a need for systematic risk evaluation. Researchers, conservation staff and tourists spend time in very close proximity of wild great apes, sometimes during
long time periods, which poses a potential risk of disease spillover. However, the presence of researchers and tourists has been shown to decrease the risk of poaching, making the matter increasingly complex.
Price transmission dynamics of Chinese ADRs listed on the NYSE
Purpose: This study aims to examine the price transmission among ADRs (American Depositary Receipts) and their underlying shares, US market index and Hong Kong market index. We will attempt to capture how a shock in the home market is transmitted to the foreign (and vice versa). In addition we will attempt to assess the relative weight of each variable in the system generating unexpected variations of its own and other variables and at what speed the shocks are absorbed.Methodology: ADF unit root test, Johansen?s co-integration test, Granger causality test, VECM, impulse response, variance decomposition Empirical foundation: Five Chinese ADRs listed on the New York Stock Exchange. Each ADR represents a specific industry.
En indirekt metod för adaptiv reglering av en helikopter
When a helicopter is flying, the dynamics vary depending on, for example, speed and position. Hence, a time-invariant linear model cannot describe its properties under all flight conditions. It is therefore desirable to update the linear helicopter model continuously during the flight. In this thesis, two different recursive estimation methods are presented, LMS (Least Mean Square) and adaptation with a Kalman filter. The main purpose of the system estimation is to get a model which can be used for feedback control.
Går det att mäta blodtryck med fotopletysmografi och bioakustisk sensor i kombination?
The aim of the work was to investigate the possibility to combine information from PPG and bio-acoustic technology to extract information that is related to the blood pressure. The measurements have been carried out with several different configurations. First the relation between arterial sounds and the PPG-signal was studied. After those measurements with both PPG and the bio- acoustic technique was concluded on people in different positions and after riding a bike. The goal was to vary the blood pressure.
Optimering av ultraljudssändare- och mottagare avseende räckvidd, strålningsvinkel och energiförbrukning
Embedded Systems Lab at Umeå University is currently part of a research project with the purpose to examine the behavior of dairy cows inside a barn. Each cow needs to be tracked with a precision of 50 cm, and since GPS-technique has poor functionality at indoor environments, an indoor positioning system needs to be developed.Embedded Systems Lab has already developed an indoor positioning system using IR-light and radio, but since this system demands extensive infrastructure and is rather expensive, an alternate positioning system using ultrasonic pulses and radio is being examined.In this report the range, beam angle and current consumption of ultrasonic transmitters- and receivers are investigated. Three different driver stages for the transmitter is tested, and two amplifier solutions for the receiver. The report also describes how the length of the transmitted ultrasonic pulse affects the received signal, accessibility of a ?shadowed? signal, and the effect of different sound frequency..
Aktiv bullerdämpning i ventilationssystem
Active headsets have been on the market for years and now it is time for
something else to enter the stage. The technology of active noise reduction can
for exmple also be used in ventilation systems for reducing ventilation noise.
An active control system principally consists of four important components,
namely the downstream error microphone, the upstream detection or reference
microphone, the digital signal processor (DSP) and a loudspeaker.
The upstream reference microphone listen to the primary ventilation noise and
sends it to the DSP which makes a phase shift to the signal and sends it to the
loudspeaker. The loudspeaker sends out the opposite waveform of the incoming
one and reduce the primary ventilation noise.
Partikelmängd i traktorers hydrauliksystem : en jämförande studie av två traktormärken med skilda respektive gemensamma oljor i hydraulik och transmission
Det finns studier som visar att skador i transmission och hydraulik är bland de vanligaste och dyraste skadorna på traktorer. Ytterligare studier visar att det finns mycket partiklar i oljorna hos lantbrukets traktorer. Även om inte partikelmängden som sådan är orsak till skadan kan den orsaka följdskador, ofta med stora kostnader som konsekvens.
Partiklarna kan komma från både inre och yttre källor. Partiklar som uppstår i traktorn uppkommer på grund av olika slitage på materialen i traktorn. Partiklar som kommer utifrån och genom yttre faktorer kommer från till exempel luftningen på hydrauliksystem eller från slarv vid påfyllning av olja.
Partikelmängd i traktorers hydrauliksystem : en jämförande studie av två traktormärken med skilda respektive gemensamma oljor i hydraulik och transmission
Det finns studier som visar att skador i transmission och hydraulik är bland de vanligaste och dyraste skadorna på traktorer. Ytterligare studier visar att det finns mycket partiklar i oljorna hos lantbrukets traktorer. Även om inte partikelmängden som sådan är orsak till skadan kan den orsaka följdskador, ofta med stora kostnader som konsekvens.
Partiklarna kan komma från både inre och yttre källor. Partiklar som uppstår i traktorn uppkommer på grund av olika slitage på materialen i traktorn.
Analys av spänningsstabilitetsberäkningar i det svenska elsystemet
Numerical simulations play a vital role in both static and dynamic stability assessment of electric power systems and the foreseeing of voltage collapse. Simulations performed by Svenska Kraftnät(SvK) are mainly done in the specialized voltage collapse predicting software tool, SPICA and the more all?purpose software tool, ARISTO.The grid operators at SvK use SPICA to predict the maximum transfer limit at specified sections (in this report the section in concerns is the southern part of Sweden i.e. interface1 4). SPICA is mainly used as an online application by using actual states from the grid, these states update every quarter of an hour.This thesis is a continuation of the master thesis SPICA ? ARISTO JÄMFÖRELSE by Jakob Katzman and Johan Fält.
Public Hear Aid
This project started when LIC Audio AB wanted help with development of a hearing aid for public rooms. The problem is that a lot of people suffer from some sort of hearing impairment. In places with a lot of people and background noise the problem becomes bigger and the sound seems to flow together. During the project we found the solution for the problem in the shape of a headphone. The headphone receives a signal from a preinstalled hearing loop.
Implementering av Constant Fraction Detection vid avståndsmätning
This thesis is performed at Saab Bofors Dynamics in Karlskoga and investigates a technique for ranging with laser pulses. The investigated technique is called Constant Fraction Detection (CFD). Described briefly, the received laser pulse is split into two equal parts, where one part is delayed half the pulse width and inverted. This signal is added to the original pulse. The resulting curve has the shape of a laying S and the detection of the zero level is used to stop the time measurement.
Signal- och bildbehandling på moderna grafikprocessorer
En modern grafikprocessor är oerhört kraftfull och har en prestanda som potentiellt sett är många gånger högre än för en modern mikroprocessor. I takt med att grafikprocessorn blivit alltmer programmerbar har det blivit möjligt att använda den för beräkningstunga tillämpningar utanför dess normala användningsområde. Inom det här arbetet utreds vilka möjligheter och begränsningar som uppstår vid användandet av grafikprocessorer för generell programmering. Arbetet inriktas främst mot signal- och bildbehandlingstillämpningar men mycket av principerna är tillämpliga även inom andra områden.Ett ramverk för bildbehandling implementeras och några algoritmer inom bildanalys realiseras och utvärderas, bland annat stereoseende och beräkning av optiskt flöde. Resultaten visar på att vissa tillämpningar kan uppvisa en avsevärd prestandaökning i en grafikprocessor jämfört med i en mikroprocessor men att andra tillämpningar kan vara ineffektiva eller mycket svåra att implementera..
Undersökning av mätsystem och regulatorstrukturer för industriella tillämpningar
This thesis is divided in to two different parts. The first part includes examination of the measurementsystem of an industrial robot using a resolver sensor. The main focus is on methods for suppressing noise in the angularvelocity signal without increasing timedelay. Five different methods are investigated. Three of these are based on oversampling: burstsamplingmethod, meanvaluemethod and correlationmethod.
FPGA-baserad multisignalgenerering med adaptiv Crestfaktor
Detta examensarbetet undersöker möjligheten att eliminera de amplitudtoppar som uppstår då flera sinussignaler av slumpmässiga frekvenser adderas. Det som eftersträvas är en signal innehållande flera godtyckliga frekvenser samtidigt som den bibehåller en låg Crestfaktor (eller PAPR). De metoder som tas fram implementeras sedan i en FPGA. Rapporten behandlar de metoder som undersökts både i teoretiska utvärderingar samt i en hårdvaruimplementation. Resultaten visar på att det inte finns någon enkel lösning på problemet, men att en kombination av metoder kan användas för att få en förbättring av signalens Crestfaktor.
Automatisk mätning och detektering av röjande signaler
This master thesis has been performed at Sectra Communications AB in Linköping where they manufacture electronic encryption devices. In cryptology it is essential that an eavesdropper cannot find the plain text. To assure that a system is safe, all devices are thoroughly examined so that they don?t emit any secret information, so called Compromising Emanations (CE). This is done by comparing the secret signal with measured signals on the screen of an oscilloscope, a process that is very time consuming and furthermore, the risk of missing compromising emanations is high.