<p>Den här uppsatsen undersöker hur andelen deltidsanställningar inom den kommunala verksamheten påverkar kommunernas personalkostnader. Flera regressionsmodeller har använts på ett material bestående av Sveriges samtliga kommuner mellan åren 1998 och 2006. Resultaten har visat att en kommun som minskar andelen deltidsanställda med tio procentenheter beräknas sänka sina personalkostnader med ca 1200 kr per kommuninvånare och år. Modellerna är signifikanta även när de kontrolleras för autokorrelation och relativt hårda antaganden om orsaksriktning och effektens fördröjning.</p><p>Även deltidsanställningarnas inverkan på kvaliteten i den kommunala verksamheten har studerats. Trots svårigheterna att mäta kvalitet, tyder resultaten på att en minskning av andelen deltidsanställningar förväntas förbättra kvaliteten.</p><p>Sammantaget visar resultaten att kommuner som erbjuder sina deltidsanställda möjlighet till heltidsanställning kan göra mindre ekonomiska vinster utan att försämra verksamhetens kvalitet. Slutsatsen har inte bara ett värde i sig, utan är även ett viktigt inlägg i diskussionen om de ekonomiska kostnaderna av en lagstiftad rätt till heltidsanställning.</p>

Aircrafttrajectory optimization is traditionally used forminimizing fuel consumption or time when going from one flightstate to another. This thesis presents a possible approach toincorporate tactical constraints in aircraft trajectoryoptimization. The stealth technology of today focuses on making thetactics already in use more effective. Since tactics andstealth are closely interrelated, new and better results may beobtained if both aspects are considered simultaneously. Simplyreducing the radar cross section area in some directionswithout considering tactical aspects may result in little, ifany, improvement. Flight tests have been performed in cooperation withEricsson Microwave Systems and the Swedish Air Force FlightAcademy. The aircraft used was the subsonic jet trainer Saab105, designated SK60 by the Swedish Air Force. The results showa decrease of 40% in the time interval between the instant theaircraft was first detected until it could pass above the radarstation. This corresponds to a reduced radar cross section(RCS) in the direction from the aircraft to the radar of almost90%, if classical RCS reduction techniques would have beenapplied. If a modern aircraft with stealth properties would be used,the proposed methodology is believed to increase the possibleimprovements further. This is because the variation of themagnitude of RCS in different directions is greater for a shapeoptimized aircraft, which is the property exploited by thedeveloped method. The methods presented are indeed an approach utilizing theideas of the network centric warfare (NCW) concept. Themethodology presented depends on accurate information about theadversary, while also providing up-to-date information to theother users in the information network. The thesis focuses on aircraft but the methods are generaland may be adapted for missiles, shipsor land vehicles. Theproposed methods are also economically viable since they areuseful for existing platforms without costly modifications. Themethods presented are not limited to radar threats only. Thereasons for using radar in this thesis are the availablenon-classified data and that radar is known to pose a majorthreat against aircraft.

Den här uppsatsen undersöker hur andelen deltidsanställningar inom den kommunala verksamheten påverkar kommunernas personalkostnader. Flera regressionsmodeller har använts på ett material bestående av Sveriges samtliga kommuner mellan åren 1998 och 2006. Resultaten har visat att en kommun som minskar andelen deltidsanställda med tio procentenheter beräknas sänka sina personalkostnader med ca 1200 kr per kommuninvånare och år. Modellerna är signifikanta även när de kontrolleras för autokorrelation och relativt hårda antaganden om orsaksriktning och effektens fördröjning. Även deltidsanställningarnas inverkan på kvaliteten i den kommunala verksamheten har studerats. Trots svårigheterna att mäta kvalitet, tyder resultaten på att en minskning av andelen deltidsanställningar förväntas förbättra kvaliteten. Sammantaget visar resultaten att kommuner som erbjuder sina deltidsanställda möjlighet till heltidsanställning kan göra mindre ekonomiska vinster utan att försämra verksamhetens kvalitet. Slutsatsen har inte bara ett värde i sig, utan är även ett viktigt inlägg i diskussionen om de ekonomiska kostnaderna av en lagstiftad rätt till heltidsanställning.

Meson production in proton-deuteron collisions has been studied using the WASA detector facility at the CELSIUS storage ring in Uppsala. Data were obtained at two different beam energies, 1360 MeV and 1450 MeV, slightly above threshold for η and ω mesons. The differential cross sections of pd → 3He ω constitute the first measurements of this reaction covering the whole angular range. The ω angular distributions are isotropic at 1360 MeV but have strong forward and backward enhancements at 1450 MeV. Theoretical calculations using a two-step model fail to reproduce the shapes of the angular distributions and underestimate the total cross sections. The tensor polarisation of the ω meson has been derived from the measured angular distributions of the ω decay products. The π+ π- π0 and the π0 γ decay channels gave consistent results, showing that the ω meson is produced unpolarised at both energies. This is in contrast to a recent MOMO measurement which showed that the Φ meson is produced almost completely polarised in the pd → 3HeΦ reaction. Different production dynamics of ω and Φ mesons close to threshold raises the question whether the Okubo-Zweig-Iizuka (OZI) rule is applicable in low-energy nucleon-nucleon reactions. The angular distributions of the η meson produced in the pd → 3He η reaction are strongly enhanced for forward going η mesons at both energies. The σ(pd → 3He π+ π- π0 )/σ(pd → 3He π0 π0 π0 ) ratio has been measured and discussed in terms of isospin amplitudes. A rough estimate of the pd → 3He π0 π0 π0 π0 cross sections has also been obtained and the pd → 3He η π0 reaction has been studied for the first time near threshold.

<p>The three essays in this dissertation explore the role of fluctuations in aggregate volatility and global temperature as sources of systemic risk. </p><p>The first essay proposes a production-based asset pricing model and provides empirical evidence suggesting that compensation for volatility risk is closely related to an unexplored characteristic of a firm, namely, its reliance on skilled labor. I propose a model in which aggregate growth has time-varying volatility, and linear adjustment costs in labor increase with the skill of a worker. The model predicts that expected returns increase with a firm's reliance on skilled labor, as well as compensation for fluctuations in aggregate uncertainty. Consequently, a rise in aggregate uncertainty predicts an increase in expected returns as well as in cautiousness in hiring and firing. This impact is larger for firms with a high share of skilled workers because their labor is more costly to adjust. I empirically test the implications of the model using occupational estimates to construct a measure of a firm's reliance on skilled labor, and find a positive and statistically significant cross-sectional relation between the reliance on skilled labor and expected returns. Empirical estimates also show that an increase in aggregate uncertainty leads to a rise in expected returns, and this impact is larger for firms which rely heavily on skilled labor; thereby, a firm's exposure to aggregate volatility is positively related to its reliance on skilled labor.</p><p>In the second and third essay, co-authored with Ravi Bansal, we explore the impact of global temperature on financial markets and the macroeconomy. In tho second essay we explore if temperature is an aggregate risk factor that adversely affects economic growth. First, using data on global capital markets we find that the risk-exposure of these returns to temperature shocks, i.e., their temperature beta, is a highly significant variable in accounting for cross-sectional differences in expected returns. Second, using a panel of countries we show that GDP growth is negatively related to global temperature, suggesting that temperature can be a source of aggregate risk. To interpret the empirical evidence, we present a quantitative consumption-based long-run risks model that quantitatively accounts for the observed cross-sectional differences in temperature betas, the compensation for temperature risk, and the connection between aggregate growth and temperature risks. </p><p>The last essay proposes a general equilibrium model that simultaneously models the world economy and global climate to understand the impact of climate change on the economy. We use this model to evaluate the role of temperature in determining asset prices, and to compute utility-based welfare costs as well as dollar costs of insuring against temperature fluctuations. We find that the temperature related utility-costs are about 0.78% of consumption, and the total dollar costs of completely insuring against temperature variation are 2.46% of world GDP. If we allow for temperature-triggered natural disasters to impact growth, insuring against temperature variation raise to 5.47% of world GDP.</p> / Dissertation

The primary goal of the recently formed Absorption Cross Sections of Ozone (ACSO) Commission is to establish an international standard for the ozone cross section used in the retrieval of atmospheric ozone number density profiles. The Canadian instrument OSIRIS onboard the Swedish spacecraft Odin has produced high quality ozone profiles since 2002, and as such the OSIRIS research team has been asked to contribute to the ACSO Commission by evaluating the impact of implementing different ozone cross sections into SASKTRAN, the radiative transfer model used in the retrieval of OSIRIS ozone profiles. Preliminary analysis revealed that the current state of the OSIRIS spectral point spread function, an array of values describing the dispersion of light within OSIRIS, would make such an evaluation difficult. Specifically, the current spectral point spread function is time-independent and therefore unable to account for any changes in the optics introduced by changes in the operational environment of the instrument. Such a situation introduces systematic errors when modelling the atmosphere as seen by OSIRIS, errors that impact the quality of the ozone number density profiles retrieved from OSIRIS measurements and make it difficult to accurately evaluate the impact of using different ozone cross sections within the SASKTRAN model. To eliminate these errors a method is developed to calculate, for the 310-350 nm wavelength range, a unique spectral point spread function for every scan in the OSIRIS mission history, the end result of which is a time-dependent spectral point spread function. The development of a modelling equation is then presented, which allows for any noise present in the time-dependent spectral point spread function to be reduced and relates the spectral point spread function to measured satellite parameters. Implementing this modelled time-dependent spectral point spread function into OSIRIS ozone retrieval algorithms is shown to improve all OSIRIS ozone profiles by 1-2% for tangent altitudes of 35-48 km. Analysis is also presented that reveals a previously unaccounted for temperature-dependent altitude shift in OSIRIS measurements. In conjunction with the use of the time-dependent spectral point spread function, accounting for this altitude shift is shown to result in an almost complete elimination of the temperature-induced systematic errors seen in OSIRIS ozone profiles. Such improvements lead to improved ozone number density profiles for all times of the OSIRIS mission and make it possible to evaluate the use of different ozone cross sections as requested by the ACSO Commission.

When simulating target seekers, there is a great need for computationally efficient, target models. This report considers a study of radar target modelling based on Inverse Synthetic Aperture Radar (ISAR) measurements of generic aircraft. The results underlie future modelling of full-size air targets. A method is developed for two-dimensional modelling of aspect-dependent target scattering. The approach taken is to generate point-scatterer models of two targets, where each point scatterer is defined according to its position and radar cross section (RCS), estimated from ISAR images. The scattered energy contributions from all point scatterers are summed to simulate a radar return signal. To validate the models, the modelled radar target centre is compared to the true radar target centre, which is determined from ISAR images. The method is presented to be promising for modelling air targets with large, persistent radar cross section.

A condensed multigroup formulation is developed which maintains direct consistency with the continuous energy or fine-group structure, exhibiting the accuracy of the detailed energy spectrum within the coarse-group calculation. Two methods are then developed which seek to invert the condensation process turning the standard one-way condensation (from fine-group to coarse-group) into the first step of a two-way iterative process. The first method is based on the previously published Generalized Energy Condensation, which established a framework for obtaining the fine-group flux by preserving the flux energy spectrum in orthogonal energy expansion functions, but did not maintain a consistent coarse-group formulation. It is demonstrated that with a consistent extension of the GEC, a cross section recondensation scheme can be used to correct for the spectral core environment error. A more practical and efficient new method is also developed, termed the "Subgroup Decomposition (SGD) Method," which eliminates the need for expansion functions altogether, and allows the fine-group flux to be decomposed from a consistent coarse-group flux with minimal additional computation or memory requirements. In addition, a new whole-core BWR benchmark problem is generated based on operating reactor parameters in 2D and 3D, and a set of 1D benchmark problems is developed for a BWR, PWR, and VHTR core.

Este trabajo resuelve el problema de gran interés para la industria aeronáutica: el cálculo de la sección recta (RCS) de blancos radar complejos en tiempo real. Para ello basta una estación de trabajo con un acelerador grafico 3-d hardware en lugar de los super-ordenadores vectoriales que requieren los métodos clásicos. El método desarrollado totalmente original e innovador, consiste en procesar gráficamente una imagen del blanco presente en la pantalla de la estación grafica. Con ello se consigue que el tiempo de cpu sea independiente del tamaño y complejidad del blanco, con lo que su principal aplicación es la estimación rápida de la RCS de blancos radar complejos. Este método, al que hemos denominado "procesado grafico", implementa las aproximaciones asintóticas de alta frecuencia que permiten obtener las principales contribuciones a la RCS: óptica física, para la reflexión en superficies; condiciones de contorno de impedancia, para la reflexión en recubrimientos absorbentes radar (RAM), método de las corrientes equivalentes para la disposición en aristas y un método grafico de iluminación global (radiosity) para las reflexiones múltiples entre superficies. Los resultados de este trabajo hacen posible, por vez primera, el diseño interactivo de formas de baja RCS "stealth" con una estación de trabajo, por lo que se ha conseguido una herramienta software para la industria aeronáutica de gran eficiencia y potencialidad en sus aplicaciones.

This paper examines the determinants of profitability using operations strategy, productivity, and service measures in the context of the U.S. domestic airline industry. Data on ten carriers was collected on a quarterly basis between 1995 and 2007. An analysis is performed separately on data prior and post 9/11 attack. It is found that operations strategy and productivity measures are significant both before and after the 9/11 attack, whereas service measures are only significant before 9/11. Some managerial implications are provided. Additionally, it is found that the profitability of full-service carriers is improving faster than low-cost carriers after 9/11.