Examensarbeten för masterexamen // Master Theses

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Measurements and Models for Direction of Arrival of Radio Waves in LOS in Urban Microcells
(2000) Chen, Ming; Chalmers tekniska högskola / Institutionen för signaler och system; Chalmers University of Technology / Department of Signals and Systems
Wideband (5MHz) measurements have been performed at 1900 MHz in a typical urban microcell using a synthetic Uniform Linear Array (ULA) at the base station. The Direction of Arrival (DOA) of the received signal is investigated using an Iterative Maximum Likelihood algorithm (IML). A 3-Ray DOA model is proposed to give the basic DOA angular spread profile with a modest T-R distance. A hypothesis of virtual Multiray DOA model is proposed to model the measurements for LOS case. The parameters sensitivity of constitutive parameter of different material, street width, MS position and base station antenna height of the virtual Multiray DOA model is investigated.
Application of IEEE 802.1X in HiperLAN type 2 Chalmers
(2001) Kelati, Amleset; Chalmers tekniska högskola / Institutionen för elektroteknik; Svensson, Arne
The research within Information Technology has been subject to a tremendous speed-up in the latest years, mainly due to the reduced prices of the related technology and, consequently, to a strongly increased interest of the users. This causes a positive feedback loop, since many companies decide to invest more money in such area, reducing further the prices and accelerating this process. One of the major issues in this big race has been the concept “Be connected always and everywhere”, which translated in an increased development of public networks on one side and in a further growth of big corporation networks on the other side. The common factors of these big areas are mobility, which implies wireless networks, and availability of services, which also means access to more or less important information. Increased size, mobility and availability of services on networks that become bigger and bigger increases tremendously the importance of data-security. Trust, authentication, and authorization have become vital key words within the design of big, mobile networks. IEEE 802.1X, also known as “Port Based Network Access Control” is a means for providing authentication and authorization for big networks that offer the possibility to many devices to attach to them, making their services available. This master thesis work, carried out at Ericsson Enterprise AB, Wireless LAN Systems in Sundbyberg (Sweden), had as a primary objective to study the authentication and authorization standard IEEE 802.1X (Draft version 11, released March 27th 2001) and its integration in HIPERLAN type 2 (HIPERLAN/2), which is a standard for wireless LAN. The project has been accomplished for the Department of Signals and Systems at the Chalmers University of Technology in Göteborg, Sweden. The goals of the thesis work were to analyze the current version of the standards and other related protocols in order to gain competence in the area of the study how IEEE 802.1x could be integrated in HIPERLAN/2 based network. In this work we propose a solution for the implementations problem and design, develop and test a basic prototype. The result shows that IEEE 802.1x can be deployed within a wireless network based on HIPERLAN/2 by adapting certain features of the two standards and by adopting certain rationale while developing an architecture based on them. This report is structured in such a way to mirror the different goals of the thesis. Part 1: Contains a description of the current version of the standard and of other related protocols that collaborate and participate in enhancing security in a typical LAN environment. Part 2: Illustrates the methodology that has been used and the achieved results in order to integrate IEEE 802.1X and an HIPERLAN/2-based network. Part 3: Describes roughly the implementation of the prototype, its limitations and further work to make it usable in a professional and non-experimental environment; furthermore, it describes the result of the testing operation. Part 4: Concludes the report by summarizing the whole work, by illustrating the achieved results and by giving some suggestions for a follow-up of this thesis work.
Modello per la stima di coppia nei motori diesel
(2003) Falcone, Paolo; Chalmers tekniska högskola / Institutionen för signaler och system; Chalmers University of Technology / Department of Signals and Systems
Low Order Approximations of Continuously Stirred Biofilm Reactors with Monod Kinetics
(2004) Göransson, Elin; Chalmers tekniska högskola / Institutionen för signaler och system; Chalmers University of Technology / Department of Signals and Systems
Design of controllers and optimization of plants using biofilm reactors often require dynamic models and efficient methods of simulation. Continuously stirred biofilm reactors (CSBRs) are useful model units in modeling of a variety of different biofilm reactors. Often the reaction kinetics in the biofilm is described by a Monod expression. Using standard modeling assumptions the equations describing the fast dynamics of a CSBR will then, for each substrate, be one nonlinear partial differential equation coupled with one linear ordinary differential equation. Here it is shown how a few nonlinear ordinary differential equations, which may be solved with standard integration methods, can be used as a close approximation. The approximations are derived using two common MWR methods, the Galerkin method and the orthogonal collocation method. Uniqueness and convergence properties are discussed. The stationary approximations can either be used as they are or to generate initial values for iterative methods to find solutions to more complicated models used, for example, in studies of the long term dynamics. Simulations of steps, impulses and random input responses using the approximations are compared to high accuracy simulations using the finite element method. The simulations show that a second order state space model is enough to describe the system for biofilms and reactors with low reaction rates and where the bulk volume is large compared to the liquid volume in the biofilm. A sixth order approximation, with a maximum error of 0.5%, should however be sufficient in almost all applications. The orthogonal collocation method turns out to have some advantages compared to the Galerkin method. It is easy to expand to higher orders, the errors are somewhat smaller, and the model expressions are simpler. Further, it is investigated how a liquid boundary layer on the biofilm surface affects the accuracy of the approximations. Simulations imply that the errors, compared to the FEM simulations, are smaller when this boundary layer is considered in the model. Finally, a collocation method where the collocation points are not chosen to be roots of orthogonal polynomials is shown to be less accurate than the standard orthogonal collocation method, where the collocation points are the roots of Legendre polynomials.
Design and Development of Tracking Antennas
(2005) Franzén, Magnus; Chalmers tekniska högskola / Institutionen för signaler och system; Chalmers University of Technology / Department of Signals and Systems
Characterization of Omni-Directional Antennas Using H-Near Field Probe
(2005) Turlapaty, Anish Chand; Chalmers tekniska högskola / Institutionen för signaler och system; Chalmers University of Technology / Department of Signals and Systems
Characterization of Reverberation Chamber for Measurements of UWB Antennas
(2005) Quevedo Teruel, Oscar; Chalmers tekniska högskola / Institutionen för signaler och system; Chalmers University of Technology / Department of Signals and Systems
Análisis y Evaluación del Throughput Máximo en Sistemas de Transmisión con Modulación y Codificación utilizando el Límite de Gallager
(2005) Alvarado, Alex; Chalmers tekniska högskola / Institutionen för signaler och system; Chalmers University of Technology / Department of Signals and Systems
TCP Measurements of GSM & 3G Phones in Reverberation Chamber at GSM 900/GSM 1800 MHz and 3G Frequency Bands
(2005) Özcan, Sadullah; Chalmers tekniska högskola / Institutionen för signaler och system; Chalmers University of Technology / Department of Signals and Systems
Experimental Studies of Operating Near-Field Antennas
(2005) Björkström, Jessica; Chalmers tekniska högskola / Institutionen för signaler och system; Chalmers University of Technology / Department of Signals and Systems
SANTANA - Smart Antenna Terminal Design
(2005) Ying, Liu; Chalmers tekniska högskola / Institutionen för signaler och system; Chalmers University of Technology / Department of Signals and Systems
Analysis of multispectral reconnaissance imagary for target detection and operator support
(2006) Brattberg, Oskar; Chalmers tekniska högskola / Institutionen för signaler och system; Chalmers University of Technology / Department of Signals and Systems
Integration of CAPSim-propulsion models in the Chalmers Vehicle Simulator
(2006) Schedel, Felix; Chalmers tekniska högskola / Institutionen för signaler och system; Chalmers University of Technology / Department of Signals and Systems
Modeling of a fork lift truck for verification of stability support system
(2006) Myhre, Martin; Ringius, Daniel; Chalmers tekniska högskola / Institutionen för signaler och system; Chalmers University of Technology / Department of Signals and Systems
Camera surveillance
(2006) Wallgren, Lucas; Chalmers tekniska högskola / Institutionen för signaler och system; Chalmers University of Technology / Department of Signals and Systems
Design and creation of a WAN simulator
(2006) Abrahamsson, Tobias; Windeman, Peter; Chalmers tekniska högskola / Institutionen för signaler och system; Chalmers University of Technology / Department of Signals and Systems
Reglering av laborationsprocess med Matlab/Simulink
(2006) Larsson, Johan; Chalmers tekniska högskola / Institutionen för signaler och system; Chalmers University of Technology / Department of Signals and Systems
Objective evaluation of response, shunt and shuffle in simulation and implementation of powertrains
(2006) Alden, Carl-Johan; Larsson, Jesper; Chalmers tekniska högskola / Institutionen för signaler och system; Chalmers University of Technology / Department of Signals and Systems
Low sample rate representation of large contaminated data sets
(2006) Macdonald, Andrew; Chalmers tekniska högskola / Institutionen för signaler och system; Chalmers University of Technology / Department of Signals and Systems
MFC screen saver for Windows based on speaker verification
(2006) Dubos, Francois; Chalmers tekniska högskola / Institutionen för signaler och system; Chalmers University of Technology / Department of Signals and Systems

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