<p>The new mobile standard Long Term Evolution delivers high data rates, small delay and a more efficiently utilized RF spectrum. A solution to maintain this performance in user dense areas or areas with bad reception is the deployment of so-called femtocells. Femtocells are small base stations that are deployed indoors and share the RF spectrum with the whole mobile network. The idea is that femtocells will increase mobile operators network coverage and capacity while it at the same time increase users data throughput. There are several challenges with femtocells, both technical and economical ones. The most debated issues is how femtocells should schedule users while operating in an environment where other femtocells and base stations are interfering. In this work we developed a simulation tool to simulate the scheduling interaction between femtocells and base stationsin order to show the performance of radio resource schedulers. This rapport also aims to evaluate an approach to a femtocell scheduler to solve this issue in a satisfying way. The report gives a description of the structure of the implemented simulation tool together with some reflections on how future designs of similar or more complex simulation environments could be done.</p>

<p>Saab Aerosystems has a long tradition and a lot of competence in the field of flight simulation. Their ambition to broaden the market horizon has led to a discussion about also selling vehicle simulation solutions, both for military and civilian use.</p><p>The aim of this thesis is to investigate the driver’s experiences of the accelerations he or she is exposed to whilst driving in rough terrain. The results may be used as a basis for future decisions and can act as a platform for the construction of an effective simulation model.</p><p>To investigate the driver’s exposure of acceleration, some kind of dynamic simulation is needed. A terrain track with both small and large obstacles where constructed. A model of a military vehicle and a civil truck where also constructed with consideration given to the original vehicles’ features. The simulation of the ride along the track was then initiated, which resulted in plots for several parameters, such as acceleration and angular acceleration for the driver relative to the track. The work was focused on the vital properties of the vehicle, such as vehicle length, position of mass centre and wheel size.</p><p>The simulations led to some conclusions concerning vehicle properties. Boogie type suspension and lever arm type suspension, vertical distance to mass centre, driver’s position, vehicle length, spring and damper for the cab and number of wheels all turned out to be vital constituents to the driver’s experience. On the other hand, properties such as coefficient of restitution and wheel size turned out to have no significant impact.</p><p>One more conclusion of the work is that CAD software works well for dynamic simulations such as the ones described in this report. It was also apparent that a quite realistic simulation could be achieved with a fairly simple vehicle model. Furthermore, it is essential to get certain parameters such as the vehicle’s length and other major construction differences realistic, otherwise all fine tuning of the vehicle model will be pointless.</p> / <p>Saab Aerosystems har en lång tradition och stor kompetens inom flygsimulering. Strävan efter ett större marknadsområde har gjort att Saab även börjat undersöka möjligheterna att sälja tjänster inom fordonssimulering för både civilt och militärt bruk.</p><p>Examensarbetet syftar till att undersöka en fordonsförares upplevelser av de accelerationer som förekommer under körning i terräng. Resultatet är tänkt att användas som beslutsunderlag och grund för att bygga upp en effektiv simuleringsmodell för bl.a. terränggående fordon.</p><p>För att undersöka accelerationerna som föraren utsätts för krävs någon form av dynamiksimulering. För ändamålet har CAD-programvaran Pro Engineer Wildfire valts. En terrängbana i form av små och stora hinder samt två fordonstyper, ett stridsfordon och en lastbil konstruerades, med verkliga förebilder som utgångspunkt. Simuleringar av fordonets färd längs terrängbanan genomfördes. Varje försök genererade grafer för en mängd olika mätvärden, såsom accelerationer och vinkelaccelerationer för föraren relativt banan. Fokus har legat på att undersöka centrala egenskaper hos fordonet såsom längd, masscentrums läge, däckstorlek m.m. och hur dessa påverkar förarens upplevelse.</p><p>Efter utförda simuleringar stod det klart att de egenskaper hos fordonet som är vitala för förarens upplevelser är boogie- och länkarmsupphängning av hjul, masscentrums läge, förarens position, fordonets axelavstånd, hyttens dämpning och fjädring samt hjulantal. Mindre relevanta för förarens upplevelse är egenskaper såsom stöttal mellan däck och mark samt däckdiameter.</p><p>Av arbetet framgick även att ett CAD-verktyg med dynamikmodul fungerar mycket väl för dynamiksimuleringar av den karaktär som behandlas i examensarbetet. Det går även att konstatera att relativt verklighetsnära fordonsbeteende går att åstadkomma utan speciellt detaljerad modell av fordonet. Det framgick också att det är av stor vikt att se till att övergripande parametrar såsom fordonets längd och principiella konstruktion överensstämmer med verkligheten. Stämmer inte detta blir alla finjusteringar av fordonsmodellen överflödiga.</p>

<p>Militära insatser i urban miljö kommer troligen att öka alltmer. Detta kräver soldater till fots eftersom dessa lättare kan förflytta sig via och mellan byggnader. Varje deltagande soldat kommer att behöva egen radioutrustning. Då stadsmiljö är ett relativt outforskat område vad gäller militär radiokommunikation är det viktigt att öka förståelsen för radiovågors utbredning i stadsmiljö. Härtill har institutionen för Informationsöverföring på FOI köpt in programmet Radiowave Propagation Simulator (RPS). RPS används i det här examensarbetet för att genomföra en beräkning för ett statiskt scenario, och till beräkningen infoga påverkan från sändares och</p><p>mottagares mobilitet. Detta utförs genom att rumsligt extrapolera kanalens impulssvar till att gälla i andra positioner än de ursprungligen var beräknade för. Kanalens impulssvar blir då modifierat så att impulssvarets utbredningsvägar får nya fördröjningstider och dess komplexa signal får ny fas.</p><p>Metoden, som har tagits fram i det här arbetet, för den rumsliga extrapoleringen har implementerats och utvärderats för ett litet scenario. Det extrapolerade resultatet har sedan jämförts med beräknade resultat från RPS. Analysen visade att metoden ger ett tillförlitligt resultat. Ett annat syfte med examensarbetet har varit att visa hur forskningsresultat (från radiokanalen) kan användas effektivare för att ge högre kvalité på forskningsresultat, både på länk- och på nätnivå.</p>

<p>The aim of this thesis is to improve the control of urea injection at the combined power and heating plant Framtidens Gärstad (FTG). Tekniska Verken i Linköping AB is the owner of the plant.</p><p>The FTG plant consists of a boiler where garbage combustion is done. From the combustion nitrogen oxides are emitted. These nitrogen oxides are hazardous to the environment. To reduce the nitrogen oxides, injection of urea into the boiler is used. Urea is an organic compound of carbon, nitrogen, oxygen and hydrogen. When urea reacts with nitrogen oxides they transform into harmless nitrogen gas and water. In the plant the urea is injected by six lances.</p><p>The control of the urea injection at FTG could be improved which would save some money for the company. This is the main reason for the aim of this thesis. It is the control of the total flow of urea to the lances that is studied in this work.</p><p>Some literature about reduction of nitrogen oxides is studied, especially reduction using urea injection. There are a lot of factors that affect how good the reduction becomes. The most important factors are the amount of urea being used and the temperature of the flue gases where the reaction with urea takes place. A model with these two factors as inputs and the content of nitrogen oxides as output is derived. This is done with experiments in the boiler and system identification. The system is modelled as a linear system.</p><p>The proposal about the improved control uses the temperature from a temperature measurement just below the urea injection in the boiler. This is a parameter that the existing control does not use. The temperature is divided into three intervals. For each interval different parameters for the function of the system and the nitrogen oxide controller are used. The nitrogen oxide controller in the proposed control is derived with help from a new method of controldesign called AMIGO.</p><p>The identification models gave good results in two of the temperature intervals. The result for the third interval was not so good. This is probably due to lack of good data.</p><p>The proposed control structure could for practical reasons not be tested online but preliminary tests using measurement data gave qualitatively reasonable results.</p><p>In order to improve the results temperature dependence has to be treated more systematically.</p>

<p>A finite element model has been developed to simulate the forming of a channel section profile with the roll forming method. The model has been optimized to experimental results with respect to strains at the edge of the sheet and spring back of the sides of the profile. Finite element models with a coarse mesh have been compared to models with a finer mesh. The models with to fine mesh become instable and a model with a rather coarse mesh was finally chosen.</p><p>Both the models with shell elements and the models with solid elements have been used in the simulations. The simulations with shell elements gave very good results both for the geometry shape and the strains at the edge of the sheet. The reaction forces at the tools found in the simulations was only half of the reaction forces fond in the experiments.</p><p>The simulations with the solid element model showed very good results for the reaction forces while the geometry shape of the sheet was really bad. The spring back was much larger in the simulations than in the experiments.</p><p>The shell element model was chosen because of the excessive spring back with the solid element model. The spring back of the sides of the sheet differs only a few percent between the simulation and the experiment results when using the shell element model. The reaction forces at the tools in the simulation are only half of the reaction forces measured in the experiments but the results from the simulations are linearly proportional to the results in the experiments. The model that finally was chosen describe both the spring back and the strains at the edge of the sheet very well. Like in the experiments there were no signs of wrinkles at the sheet in any of the simulations.</p>

<p>Den här uppsatsen handlar om utvecklingen av en radiolänkssimulator åt företaget Icomera. Icomera inriktar sig på att sälja och distribuera internetåtkomst på tåg. Företagets affärsidé bygger på att sälja system som använder sig av olika trådlösa länkar som simultant skickar och tar emot data med hjälp av ett egenutvecklat protokoll. Icomera har sålt sitt system till bl.a. Statens järnvägar (SJ), för att möjliggöra internetåtkomst från tågen. Radiolänkssimulatorn används idag i Icomeras laboratorium vid testning och verifiering av tågsystemet, i och med att den ger en mer kontrollerad miljö än ett riktigt tåg.</p><p>Rapporten redogör för hur trådlösa länkar beter sig i verkligheten och hur deras beteende kan simuleras. Rapporten berör främst de problematiska delarna av implementationen, men också teori i form av bl.a. statistiska modeller.</p><p>Radiolänkssimulatorn har till största del skrivits i programspråket C# .NET, vilket har lett till flera olägenheter som behandlas i rapporten. De flesta olägenheter har främst med prestandaförluster att göra.</p> / <p>This master thesis deals with the creation of a link simulator to be used by the company Icomera. Today the link simulator is used in Icomera’s laboratory for simulating wireless links. Icomera’s business concept is to sell and distribute internet access on trains and other vehicles. They use different wireless connections for simultaneously transfer data wrapped in their own protocol. Icomera has sold the system to Statens järnvägar (SJ), to enable internet access from trains. The link simulator is used for testing and verification of Icomera’s train system. Hence it can be done in a more controlled environment than onboard a real train.</p><p>The report describes how wireless links acts in reality and how this behavior can be simulated. The report handles mainly the problematic parts of the implementation but also theory, e.g. statistic models.</p><p>The link simulator has primarily been written in the programming language C# .NET which has lead to several inconveniences which is discussed in the report. Most of the inconveniences have to do with performance loss.</p>

<p>This Master Thesis presents TMVOC simulations of a NAPL-spill (non-aqueous phase liquid) and following pumping remediation. TMVOC is a simulation program for three-phase non-isothermal multicomponent flow in saturated-unsaturated heterogeneous media. The models presented are based on an actual remediation project. The aim of the thesis was to study if the historical development of the NAPL-spill could be simulated and how long time the pumping remediation would take. A 3D-model and a radially symmetric cylindrical model were created.</p><p>A large effort of the work done was in taking the complex TMVOC model in use and modifying it for the problem at hand. Therefore, the numerical results of the simulations should be considered as preliminary and as forming basis for future studies.</p><p>The results from the spill simulation and historical pumping simulation indicated that the spill volume could be less than the estimated 1400 m³, perhaps around 700 m³, assuming a leakage time of 30 years.</p><p>The historical pumping simulation of a 700 m³ diesel spill showed good agreement with measured values for some wells, but overestimated the recovery in other wells. The overestimation could be due to the fact that the 3D-model did not take seasonal changes in the groundwater level into consideration. Also, the model did not account for any heterogeneity or compartmentalization in soil material properties that could explain the differences between the wells. </p><p>Assuming the same spill of 700 m³, future pumping was simulated. The results from these simulations indicated the remediation time to be long due to fast decreasing mobility of the NAPL phase. The NAPL flow rate to the wells was halved in a couple of years. Much of the NAPL was distributed over a large area at near residual saturation with the highest NAPL saturation found at the opposite side of the pumping wells in the model.</p><p> </p><p>Future simulation studies should address the effect of discretization as well as the effect of uncertainties in material properties e.g. conductivity, residual NAPL saturation and soil heterogeneity.</p>

Hvordan kan en omkostningskalkulationsmodel udformes under moderne og fleksible produktionsforudsætninger, og hvordan påvirker stokastikken fra produktionen en given kalkulationsmodel, når der tages højde for samtlige indsatte ressourcer fra produktionen? Disse forhold er diskuteret med udgangspunkt i den existerende kalkulationsteori på området og i relation till to konkrete case-virksomheder. For at kunne gøre konkrete beregninger af stokastikkens virkninger, er der udformet en model baseret på et FMS-system, som har været testet via stokastisk simulering. Resultatet heraf viste, at variationer i processerne, transport og leadtid kan have relativ stor effekt på stykomkostningerne sammenliget med det deterministiske tilfælde. Med en stokastisk omkostningsmodel er der også mulighed for, at estimere effekten fra Design For Manufacturability (DFM) via standardafvigelsen. Dermed bliver det muligt att søge efter at minimere stokastikken og variationen fra produktionen. / Diss. Stockholm : Handelshögskolan

The building sector alone accounts for almost 40% of the total energy demand and people spend more than 80% of their time indoors. Reducing energy demand in buildings is essential to the achievement of a sustainable built environment. At the same time, it is important to not deteriorate people’s health, well-being and comfort in buildings. Thus, designing healthy and energy-efficient buildings is one of the most challenging tasks. Evaluation of buildings with a broad perspective can give further opportunities for energy savings and improvement of the indoor climate. The aim of this thesis is to understand the functionality, regarding indoor climate and energy performance, of a low-energy building. To achieve this, a multi-dimensional approach is used, which means that the building is investigated from several points of views and with different methods. A systems approach is applied where the definition of the system, its components and the border to its environment, is essential to the understanding of a phenomenon. Measurement of physical variables, simulations, and qualitative interviews are used to characterize the performance of the building. Both energy simulation and computational fluid dynamic simulations are used to analyse the energy performance at the building level as well as the indoor climate at room level. To reveal the environmental impact of the low-energy building studied in this thesis the CO2 emissions and embodied energy have been investigated regarding different surrounding energy systems. The evaluated building is situated at the west coast of Sweden and uses about 50% of energy compared to a comparable ordinary Swedish building. The building is well-insulated and an air-to-air heat exchanger is used to minimise the heat losses through ventilation. The houses are heated mainly by the emissions from the household appliances, occupants, and by solar irradiation. During cold days an integrated electrical heater of 900 W can be used to heat the air that is distributed through the ventilation system. According to measurements and simulations, the ventilation efficiency and thermal environment could be further improved but the occupants are mostly satisfied with the indoor climate. The control of the heating system and the possibility for efficient ventilation during summertime are other important issues. This was found through quantitative measurements, simulations and qualitative interviews. The low-energy building gives rise to lower CO2 emissions than comparable buildings, but another energy carrier, such as district heating or biofuel, could be used to further improve the environmental performance of the building. The total energy demand, including the embodied energy, is lower than for a comparable building. To understand the functionality of a low-energy building both the technical systems and the occupants, who are essential for low-energy buildings, partly as heat sources but mainly as users of the technical systems, should be included in the analysis.

Value-at-Risk (VaR) is among financial institutions a commonly used tool for measuring market risk. Several methods to calculate VaR exists and different implementations often results in different VaR forecasts. An interesting implementation is historical simulation, and the purpose of this thesis is to examine whether historical simulation with dynamic volatility updating is useful as a model to calculate VaR and how this differs in regard to type of asset or instrument. To carry out the investigation six different models are implemented, which then are tested for statistical accuracy through Christoffersens test. We find that incorporation of volatility updating into the historical simulation method in many cases improves the model. The model also generates good results compared to other commonly used models, especially if the volatility is predicted through a GARCH(1,1) updating scheme. / Value-at-Risk (VaR) är ett bland finansiella institutioner vanligt mått för att mäta marknadsrisk. Det finns ett flertal olika sätt att beräkna VaR, vilka ofta ger olika resultat beroende på förutsättningar. Ett av dessa är historisk simulering, och syftet med denna uppsats är att undersöka huruvida historisk simulering med dynamiskt uppdaterande volatilitet är en användbar modell för beräkning av VaR och hur dess lämplighet beror på valt tillgångsslag eller instrument. För att besvara detta implementeras sex olika modeller för beräkning av VaR, vilka sedan testas med hjälp av Christoffersens test. Vi finner att inkorporering av dynamisk volatilitet i historisk simulering i många fall medför en förbättring av modellen ifråga om statistisk riktighet. Vidare kan historisk simulering med dynamiskt uppdaterande volatilitet anses vara konkurrenskraftig i jämförelse med andra vanligt använda modeller, framförallt då volatiliteten skattas genom GARCH(1,1).