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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.
11

Policy Analysis for Different Types of Decision-Making Situations

Andersson, Matts January 2017 (has links)
This thesis seeks to contribute to decision support for policy makers in the transport sector. In order to frame the papers and to relate them to the broad field of “policy analysis”, I have structured the papers around a simple framework with three decision levels: responsibility, policy gap, and policy measure. The thesis contains five papers. “Transaction and transition costs during the deregulation of the Swedish Railway market” is a paper in the transaction cost school. We studied the costs associated with the shift from monopoly to competition in the Swedish railway market, and we found that the change resulted in comparatively small transaction costs, but that transition and misalignment costs seem to be larger.  In “Parking policy under strategic interaction”, I examined the effect of strategic interaction between jurisdictions using an analytical model based on Hotelling’s linear city model. I conclude that the procedure for setting supply in most municipalities has a strong downward effect on municipal parking fees and that resource flow competition implies that the fees are higher than the efficient prices (but that the effect of the supply procedures makes this effect incongruous). In “Validation of aggregate reference forecasts for passenger transport”, we followed up the Swedish national forecasts for passenger transport produced from 1975 to 2009 and tried to explain the deviations. We found that the forecasts during the last decades have overestimated car traffic, and that this is due to input errors. The potential problem of using cross-sectional models for forecasting intertemporal changes seems to have been limited. In “The kilometer tax and Swedish industry - effects on sectors and regions”, we estimated factor demand elasticities in the Swedish manufacturing industry and used these to analyze the effects of a kilometer tax for heavy goods vehicles. We found that the kilometer tax leads to factor substitution in that it decreases transport demand and increases labor demand. The effects on output are less pronounced.   In “The effect of minimum parking requirements on the housing stock”, we used a model of the rental, asset, and construction markets. We quality-assured our assumptions and our results through interviews with market actors. In our example suburb, we found that parking norms reduced the housing stock by 1.2% and increased rents by 2.4%. / <p>QC 20171026</p>
12

Variability analysis of a sample of potential southern calibration sources

Hungwe, Faith January 2009 (has links)
A considerable number of Very Long Baseline Interferometry (VLBI) surveys have been conducted in the northern hemisphere and very few in the southern hemisphere mostly because of a lack of telescopes and therefore adequate baseline coverage. Thus there is a deficit of calibrator sources in the southern hemisphere. Further, some of the most interesting astronomical objects eg. the galactic centre and the nearest galaxies (the small and large Magellanic Clouds) lie in the southern hemisphere and these require high resolution studies. With a major expansion of radio astronomy observing capability on its way in the southern hemisphere (with the two SKA (Square Kilometre Array) precursors, meerKAT (Karoo Array Telescope) and ASKAP (Australian SKA Pathfinder), leading to the SKA itself) it is clear that interferometry and VLBI in the southern hemisphere need a dense network of calibration sources at different resolutions and a range of frequencies. This work seeks to help redress this problem by presenting an analysis of 31 southern sources to help fill the gaps in the southern hemisphere calibrator distribution. We have developed a multi-parameter method of classifying these sources as calibrators. From our sample of 31 sources, we have 2 class A sources (Excellent calibrators), 16 class B sources (Good calibrators), 9 class C sources (Poor calibrators) and 4 class D sources (Unsuitable calibrators).
13

Front-end considerations for next generation communication receivers

Roy, Mousumi January 2011 (has links)
The ever increasing diversity in communication systems has created a demand for constant improvements in receiver components. This thesis describes the design and characterisation of front-end receiver components for various challenging applications, including characterisation of low noise foundry processes, LNA design and multi-band antenna design. It also includes a new theoretical analysis of noise coupling in low noise phased array receivers.In LNA design much depends on the choice of the optimum active devices. A comprehensive survey of the performance of low noise transistors is therefore extremely beneficial. To this end a comparison of the DC, small-signal and noise behaviours of 10 state-of-the-art GaAs and InP based pHEMT and mHEMT low noise processes has been carried out. Their suitability in LNA designs has been determined, with emphasis on the SKA project. This work is part of the first known detailed investigation of this kind. Results indicate the superiority of mature GaAs-based pHEMT processes, and highlight problems associated with the studied mHEMT processes. Two of the more promising processes have then been used to design C-band and UHF-band MMIC LNAs. A new theoretical analysis of coupled noise between antenna elements of a low noise phased array receiver has been carried out. Results of the noise wave analysis, based on fundamental principles of noisy networks, suggest that the coupled noise contribution to system noise temperatures should be smaller than had previously been suggested for systems like the SKA. The principles are applicable to any phased array receiver. Finally, a multi-band antenna has been designed and fabricated for a severe operating environment, covering the three extremely crowded frequency bands, the 2.1 GHz UMTS, the 2.4 GHz ISM and the 5.8 GHz ISM bands. Measurements have demonstrated excellent performance, exceeding that of equivalent commercial antennas aimed at similar applications.

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