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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

Multiterminal Source-Channel Coding

Wolf, Albrecht 26 September 2019 (has links)
Cooperative communication is seen as a key concept to achieve ultra-reliable communication in upcoming fifth-generation mobile networks (5G). A promising cooperative communication concept is multiterminal source-channel coding, which attracted recent attention in the research community. This thesis lays theoretical foundations for understanding the performance of multiterminal source-channel codes in a vast variety of cooperative communication networks. To this end, we decouple the multiterminal source-channel code into a multiterminal source code and multiple point-to-point channel codes. This way, we are able to adjust the multiterminal source code to any cooperative communication network without modification of the channel codes. We analyse the performance in terms of the outage probability in two steps: at first, we evaluate the instantaneous performance of the multiterminal source-channel codes for fixed channel realizations; and secondly, we average the instantaneous performance over the fading process. Based on the performance analysis, we evaluate the performance of multiterminal source-channel codes in three cooperative communication networks, namely relay, wireless sensor, and multi-connectivity networks. For all three networks, we identify the corresponding multiterminal source code and analyse its performance by the rate region for binary memoryless sources. Based on the rate region, we derive the outage probability for additive white Gaussian noise channels with quasi-static Rayleigh fading. We find results for the exact outage probability in integral form and closed-form solutions for the asymptotic outage probability at high signal-to-noise ratio. The importance of our results is fourfold: (i) we give the ultimate performance limits of the cooperative communication networks under investigation; (ii) the optimality of practical schemes can be evaluated with respect to our results, (iii) our results are suitable for link-level abstraction which reduces complexity in network-level simulation; and (iv) our results demonstrate that all three cooperative communication networks are key technologies to enable 5G applications, such as device to device and machine to machine communications, internet of things, and internet of vehicles. In addition, we evaluate the performance improvement of multiterminal source-channel codes over other (non-)cooperative communications concepts in terms of the transmit power reduction given a certain outage probability level. Moreover, we compare our theoretical results to simulated frame-error-rates of practical coding schemes. Our results manifest the superiority of multiterminal source-channel codes over other (non-)cooperative communications concepts.
2

En kartläggning av introduktionsprocessen för nyanställda : En studie genomförd på två restauranger

Mathisson, Sebastian, Afram, Ramin January 2016 (has links)
Introduktionsprocesser är en viktig del i många verksamheter och speciellt inom restaurangbranschen där nyanställda snabbt ska kunna arbeta självständigt. Restaurangbranschen är också en av de branscherna med högst personalomsättning, vilket kan vara ett problem. Med en genomtänkt och förbättrad introduktion vid nyanställning kan organisationer få sina anställda förstå de mål, visioner och strategier som organisationen satt upp. Detta kan då leda till att personal stannar längre på arbetsplatsen. Målsättningen med denna studie har varit att kartlägga och jämföra hur introduktionen ser ut för nyanställda inom restaurang A och B och vilka åtgärder som kan göras för att förbättra introduktionen med hjälp av etablerade teorier och modeller inom informationslogistik. För att besvara studiens forskningsfrågor har ett deduktivt angreppssätt använts där vi som undersökare gått från empiri till teori. Den data som samlats in kommer från intervjuer och enkätundersökningar som var metodvalen för undersökningen. Två stycken restaurangers introduktionsprocesser för nyanställda kartlades för att se hur de arbetar med introduktionen för nyanställda. Undersökningen gjordes med de ansvariga för respektive introduktion och de personer som varit anställda två år eller kortare. Med hjälp av de intervjuer och enkätundersökning som genomfördes med ansvariga restaurangchefer och anställda inom restaurang A och B kunde en kartläggning av nuläget presenteras. De diskussioner som förts från resultatet av studien har visat att ansvariga för introduktionerna saknar dokumentation för hur processen ska gå till. Introduktion har därför kunnat bli skiftande beroende på hur och när den genomförts. En etablerad introduktionsprocess bör införas, för att varje nyanställd ska få samma förutsättningar att kunna utföra sitt arbete enligt restaurangernas mål, visioner och strategier. De slutsatser som studien presenterar visar på förbättringsförslag genom den empiri som samlats in har kopplats ihop med teori, modeller och tidigare forskning. Dessa förbättringar har skapat introduktionsplan med etablerade processer. / Introduction processes are an important part of many activities, especially in the catering industry, where new employees can quickly work independently. The catering is also one of the sectors with the highest turnover, which could be a problem. With a well thought out and improved introduction for new employees, companies can get their employees to understand the goals, visions and strategies that the company had set up. This can then lead to staff staying longer at work. The aim of this study was to identify and compare how the introduction looks for new employees in the restaurant A and B and the measures that can be done to improve the introduction using the established theories and models in information logistics. To answer the thesis research questions, have a deductive approach been used where we as investigators passed from empiricism to theory. The data collected from interviews and surveys were elections approach for the investigation. Two restaurant's introduction process for new employees was surveyed to see how they work with the introduction of new employees. The survey was conducted with those responsible for each introduction and the people who have been employed for two years or less. With the help of interviews and surveys we conducted with responsible restaurant managers and employees of the restaurant, A and B could be an overview of the current situation presented. The discussions of the results of the study have shown that responsible for the introductions have no documentation of how the process should be conducted. Introduction has therefore been able to be varied depending on how and when it is completed. An established introduction process should be introduced to each new employee should have the same opportunities to carry out their work according to the restaurant's goals, visions and strategies. The conclusions of the thesis present the shows of improvement proposals by the empirical evidence gathered has been linked with the theory, models and previous research. These improvements have created introductory plan with established processes.

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