Saab takes great measures to ensure that the cockpit is a great working environment for the pilot. This paper aims to expand the knowledge of thermal comfort by assembling Saab’s atmosphere-, cabin and pilot-models. In order to ensure the viability of the assembled model, a qualitative study was performed with test pilots. The interviews were reduced to a few flight cases, which were tested in the assembled model to verify that the thermal discomforts that the pilots experience could be accurately predicted. Furthermore, a prediction of comfort, according to European standards, was implemented. From the interviews situations when the pilot feel discomfort could be identified, two flight cases situations and one ground case. The model simulate how the thermal environment affect the pilot, hence only the two flight cases could be analyzed. The result from the model shows the temperature in those body parts that the pilots have expressed are uncomfortable. Predicted Mean Vote, PMV, predicts comfort on a 6-degree scale, given environment parameters such as pressure and temperature. The Predicted Percentage Dissatisfied, PPD, describes the number of people, in percent, who are uncomfortable at a given PMV. These measures of comfort were used to compute the comfort in the different parts of the body. The model simulation agrees with the pilot’s experiences in some of the body parts, but not all of them. By taking the humidity into account the simulation result may be more accurate. The humidity increases the PPD value in case 2 when the humidity increases. Finally, in order to adopt the comfort analysis presented in this paper, the model had to be revised, and updated with increased detail. / Saab gör stora satsningar för att säkerställa att cockpiten är en god arbetsplats för piloten. Den här rapporten syftar till att öka kunskapen om termisk komfort genom att kombinera Saabs atmosfärs-, kabin-, och pilotmodeller. För att kunna verifiera att den kombinerade modellen beskriver verkligheten genomfördes en kvalitativ studie med testpiloter. Intervjuerna reducerades till ett par flyg-scenarier, som sedan testades i den kombinerade modellen. Detta för att kunna verifiera att de upplevda obekvämligheterna kunde förutspås. Den kombinerade modellen utökades med en prediktion av bekvämligheten enligt Europeisk standard. Ur intervjuerna kunde situationer identifieras då piloterna känner termiskt obehag. Av dessa situationer är två flygfall och ett markfall, där piloten befinner sig utanför cockpit. Modellen simulerar hur piloten påverkas av den termiska miljön i kabin, på grund av detta kunde inte markfallet analyseras. Modellsimuleringen resulterade i figurer som visar temperaturen i kroppsdelar som piloterna har uttryck känns obehagliga. Predicted Mean Vote, PMV, förutspår komfort på en 6-gradig skala givet omgivningsparametrar så som tryck och temperatur. Predicted Percentage Dissatisfied, PPD, beskriver hur stor andel, i procent, som upplever obehag vid ett givet PMV. Dessa mått på komfort användes för att beräkna komforten i de olika kroppsdelarna. Modellsimuleringen av pilotkomforten stämmer överens med det piloterna nämnde till viss del. I vissa kroppsdelar stämmer det inte överens. Då modellen inte tar hänsyn till fuktighet vid beräkning av kroppstemperaturer kan detta vara en anledning till varför den inte stämmer helt. Fuktigheten påverkar PMV och PPD beräkningarna och i fall 2 visar det sig att PPD ökar med en ökad fuktighet. Slutligen, behöver modellens ses över, och detaljgraden ökas, för att den här rapportens metoder skall vara användbara vid tillverkningen av flygplan.

This Master's thesis examines the problem of optimal investment when corporate taxes have to be paid on capital gains. Tax payments share a lot of similarities with payoff from a call option where the underlying is the firm's capital. How to optimally deal with this tax-option is a non-trivial problem that is complicated by the feedback between the value of the tax-option and the strategy the firm uses to handle it. For the case with only one tax payment it is possible to derive an explicit expression for the optimal strategy using a martingale method. The tax payment introduces some interesting properties to the optimal wealth process, such as a non-zero probability of ending up exactly at the tax basis at the terminal date.   The optimal strategy is then generalized to the problem with multiple tax payments using the martingale framework. A numerical method of calculating the optimal strategy based on trinomial trees is also presented and implemented. This is then used to verify the theoretical results and to calculate the optimal strategy with an increasing number of tax payments.  For the case with only one tax payment at a terminal date numerical results show that the increase in utility is small and a close to optimal strategy can be derived by ignoring tax. With multiple tax payments however, the increase in utility from using the tax-optimal strategy is significant. / Den här Masteruppsatsen undersöker problemet med optimal investering för ett företag som måste betala skatt på kapitalvinster. Skattebetalningar har många likheter med utfallet för en köpoption där det underliggande är företagets kapital. Att hantera denna skatteoption optimalt är ett icke-trivialt problem, som kompliceras av återkopplingen mellan värdet på skatteoptionen och den strategi företaget använder för att hantera den. För fallet med enbart en skattebetalning är det möjligt att härleda ett explicit uttryck för den optimala strategin med en martingalmetod. Skattebetalningen introducerar några intressanta egenskaper hos den optimala kapitalprocessen, såsom en nollskild sannolikhet att hamna exakt på omkostnadsvärdet vid slutdatum.  The optimala strategin generaliseras sedan till problemet med flera skattebetalningar inom ramverket för martingalmetoden. En numerisk metod för att beräkna den optimala strategin baserad på trinomialträd presenteras också och implementeras. Den används sedan för att verifiera det teoretiska resultatet och beräkna den optimala strategin med ett ökande antal skattebetalningar.  För fallet med enbart en skattebetalning vid slutdatum visar det numeriska resultatet att ökningen i nytta är litet och en strategi nära den optimala kan härledas utan att inkludera skatt. Med flertalet skattebetalningar är dock nyttoökningen från användandet av den skatteoptimala strategin betydande.

Work in control rooms, or so-called Centers of coordination, places demands both on humans and technology. The people working there have to be able to make quick decisions as well as be alert during less busy times. The work has to be coordinated within the group, since the operators are much depending on each other's work. This places special demands on the technology; it should be fast, trustworthy and easy to manipulate so that the complexity of the work is reduced. This type of work has been a source of interest in the research area of Computer Supported Cooperative Work, especially so since the needs for real-time coordination is great in these settings. SOS Alarm is a company that is responsible for managing the telephone calls made to the emergency number 112 in Sweden. They have 20 centers covering Sweden. This thesis present an overview of the SOS operators work; how they coordinate the information and tasks between them; how the technology supports that work. This study presents a fully computerized setting, compared to many other studies of centers of coordination that are not. This ethnographic workplace study has been inspired by ethnomethodological perspectives as well as earlier field studies of work and technology use. Its main results are a description of the work practice and technology at two centers, implications for design of a new computer aided dispatch system that is currently developed at SOS Alarm and general design ideas for control rooms.

We consider network modelling and numerical simulation of a simple CO2 heat pump consisting of a compressor, a valve and two heat exchangers. In a first step we investigate analytical and numerical properties of the heat exchanger model. The heat exchanger model is derived from the Euler equations under the assumption that the velocity of the refridgerant flow is small compared to the local speed of sound. While the Euler equations form a hyperbolic system, the character of the new system, called The zero Mach number limit of the Euler equations, is unclear. The lack of a time derivative in the momentum equation makes the heat exchanger model by itself a PDAE system. We analyse a frozen-coefficient linearisation of the heat exchanger model by transformation to a canonical form. The canonical form reveales that the system is equivalent to a hyperbolic equation and a parabolic block. The parabolic block is equivalent to a parabolic equation and an algebraic-differential relation, similar to the system that results when the heat equation ut = uxx + f is written as a first order system. We prove a stability estimate suggesting that the solution is more sensitive to perturbations, especially in time-dependent boundary conditions, than is indicated by previous results. Furthermore, we consider semidiscretisation of the linearised heat exchanger model. In a method of lines approach using collocation at the gridpoints, we suggest that it is possible to use a simple first order difference scheme taking into account the direction of the flow and the boundary conditions. We show that using this difference scheme, the solution to the semidiscrete equations satisfies a discrete analogue to the stability estimate in the continuous case. The results of the linear analysis is verified in numerical experiments with the nonlinear heat exchanger model. / QC 20101126

QC 20101116

Chromatography is a separation technique used predominantly by the medical industry in purification and extraction of components in a solution. The setup is a column filled with resin particles where a solution of two components is filtered and separated due to different rates of interaction with the resin particles. The process is often a performed at large scale with fixed manufacturing schedules and it is suggested that simulation of the process could improve efficiency of scheduling and production, thus provide more affordable medication. The purpose of this thesis is to simulate liquid chromatography with a Discontinuous Galerkin (DG) method, which is a finite element method based derivation to solve partial differential equations. This is done by applying the DG method to a Equilibrium-Dispersive Model (EDM) for Chromatography and implementing the key functions in a Python package used in the simulation. For the flux function of the DG-method, a central flux was used and for the time domain discretization a low storage Runge-Kutta method was used. The implementation was tested with square injection profiles and compared with a equilibrium disperse model, a Laplace based solver, from which L1 and L2 error norms could be computed. The results showed that the software produced very promising results for a dispesion of $D=10-3-10-4 since the concentration curve becomes very smooth and predictable. For steeper concentration curves D&lt;10-3 the solver created oscillations around the, almost step like curve, to account for the discontinuity leading to the error norms being higher, $errL1~ 10-1 and errL2 ~10-3. The solver responds well to grid refinement for accuracy purposes until Nt&gt;100 and had a much faster evaluation time than the EDM-solver for this type of grid, where a linear behaviour could be noted. The evaluation time was kept bellow 21s for Nt=103 points. For time step refinement with set grid of Nt=103, a quadratic dependence in evaluation time was noted, with computational time below 10s for <img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?%5CDelta" data-classname="equation" data-title="" />t <img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?%5Cleq" data-classname="equation" data-title="" />10-4 but rising above 70s for <img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?%5CDelta" data-classname="equation" data-title="" />t = 10-5.

A continuous adjoint formulation for exterior optimization of Dirichlet data on the boundary for potential flow applications has been developed in this thesis. This has been performed by utilizing boundary integral methods for both the primal problem (Laplace’s equation) and for the corresponding adjoint equation (Poisson’s equation) on the unit disc. A considerable portion is devoted to the estimation of the boundary flux for Poisson’s equation. The boundary flux is the (unique) Riesz-representer that determines the search direction in descent methods where the optimal control problem is to reconstruct the Dirichlet data on the boundary in order to minimize a quadratic functional. / I denna uppsats behandlas adjoint baserad optimering av Dirichlet data på randen för exteriöra problem relaterat till fluiddynamik. Detta har gjorts med randintegral-metoder för det primära problemet (Laplace’s ekvation) samt för den korresponderande adjoint- ekvationen (Poisson’s ekvation). Ett stort fokus är estimering av flödet vid randen för Poisson’s ekvation på enhetsdisken. För det primära Dirichlet problemet så bestämmer detta flöde sökriktningen i gradientbaserade optimeringmetoder där målet är att rekonstruera Dirichlet-datat på randen för att minimera en kvadratisk funktional.

Modeling surface adsorption requires systems of hundreds of atoms. To model such systems at an ab initio level successfully, we need to avoid traditional quantum chemical methods. In the present work we have shown that density functional theory is a powerful modeling tool for large chemical systems especially in combinations with pseudopotentials This is validated by an initial study of ethyl and heptyl xanthates and their sodium/potassium salts. In this study, all electron calculations using both Hartree-Fock and density functional theory methods are compared with experimental infrared results. To do this the influence of basis sets and modeling approaches on the geometrical structure and the vibrational modes are examined. This includes comparing the pseudopotential and full electron potential approaches. Results obtained from pseudopotential methods are in close agreement with both all electron calculations as well as experimental results, here used to study adsorption of heptyl xanthate ZnS surfaces. Vibrational frequencies of the adsorbed species is presented, together with calculations of the tilt angles. The investigation of the tilt angles resulted in 20.3° 20.6° and 25.2° for the 100, 110 and 111 surfaces respectively. Heptyl xanthate forms a bridging confirmation on both the 110 and 111 surfaces and a bidentate confirmation on the 100 surface. Assignments of vibrational modes of ethyl/heptyl xanthate molecule and its corresponding potassium/sodium salts are also reported. / <p>Godkänd; 2005; 20070108 (haneit)</p>

This thesis is focused on the Occupational Pension, an important part of the retiree’s total pension. It is paid by private insurance companies and determined by an annuity divisor. Regression modeling of the annuity divisor is done by using the monthly paid pension as a response and a set of 24 explanatory variables e.g. the expected remaining lifetime and advance interest rate. Two machine learning algorithms, artificial neural networks (ANN) and support vector machines for regression (SVR) are considered in detail. Specifically, different transfer functions for ANN are studied as well as the possibility to improve the SVR model by incorporating a non-linear Gaussian kernel. To compare our result with prior experience of the Swedish Pensions Agency in modeling and predicting the annuity divisor, we also consider the ordinary multiple linear regression (MLR) model. Although ANN, SVR and MLR are of different nature, they demonstrate similar performance accuracy. It turns out that for our data that MLR and SVR with a linear kernel achieve the highest prediction accuracy. When performing feature selection, all methods except SVR with a Gaussian kernel encompass the features corresponding to advance interest rate and expected remaining lifetime, which according to Swedish law {Swedish law: 5 kap. 12 § lagen (1998:674) om inkomstgrundad ålderspension} are main factors that determine the annuity divisor. The results of this study confirm the importance of the two main factors for accurate modeling of the annuity divisor in private insurance. We also conclude that, in addition to the methods used in previous research, methods such as MLR, ANN and SVR may be used to accurately model the annuity divisor. / Denna uppsats fokuserar på tjänstepensionen, en viktig del av en pensionärs totala pension. Den utbetalas av privata försäkringsbolag och beräknas med hjälp av ett så kallat delningstal. Regressionsmodellering av delningstalet görs genom att använda den månatliga utbetalda pensionen som svar och en uppsättning av 24 förklarande variabler såsom förväntad återstående livslängd och förskottsränta. Två maskininlärningsalgoritmer, artificiella neuronnät (ANN) och stödvektormaskiner för regression (SVR) betraktas i detalj. Specifikt så studeras olika överföringsfunktioner för ANN och möjligheten att förbättra SVR modellen genom att införa en ickelinjär Gaussisk kärna. För att jämföra våra resultat med tidigare erfarenhet från Pensionsmyndigheten vid modellering och förutsägande av delningstalet studerar vi även ordinär multipel linjär regression (MLR). Även om ANN, SVR och MLR är av olika natur påvisar dem liknande noggrannhet. Det visar sig för vår data att MLR och SVR med en linjär kärna uppnår den högsta noggrannheten på okänd data. Vid variabel urvalet omfattar samtliga metoder förutom SVR med en Gaussisk kärna variablerna motsvarande förväntad återstående livslängd och förskottsränta som enligt svensk lag är huvudfaktorer vid bestämning av delningstalet. Resultatet av denna studie bekräftar betydelsen av huvudfaktorerna för noggrann modellering av delningstalet inom privat försäkring. Vi drar även slutsatsen att utöver metoderna som använts i tidigare studier kan metoder såsom ANN, SVR och MLR användas med framgång för att noggrant modellera delningstalet.

In this thesis dual-pair summation-by-parts-operators were optimized to propagate seismic surface waves as accurately as possible. The resulting operators were tested on a problem consisting of pure surface waves, so-called Rayleigh waves, as well as a point-source receiver problem with a vertical point force. An error study as well as a convergence study was carried out, and the results were compared to errors and convergence rates obtained using previously derived summation-by-parts-operators. The results show that there is something to be gained from optimizing for seismic surface waves. For pure Rayleigh waves, we observe smaller errors than with existing summation-by parts operators. This improvement is most apparent for elastic materials with low shear wave speed. The optimization technique used did not ensure that a global minimum of the objective function was reached, which makes exploring other optimization techniques a possible extension of this work. Other examples of future work are to explore other objective functions as well as carry out more experiments on other kinds of waves and topographies.