Higher speeds and higher capacity will cause the Swedish rail network to be exposed to disturbing dynamic effects. Higher speeds cause higher vertical acceleration levels of the bridge deck. In this thesis, a numerical analysis of a three span end-frame bridge subjected to train induced vibrations is performed. The aim is to identify which structural components and boundary conditions that affect the dynamic behavior of the bridge. Furthermore, the influence of soil structure interaction (SSI) will be investigated as it may have contribution to the stiffness and damping of the structural system.  In order to capture the dynamic response of the bridge, an analysis in the frequency domain was preformed where frequency response functions (FRF) and acceleration envelopes were obtained. For this purpose, a detailed FE-model in 3D was created. Three different cases were studied, model subjected to ballast, model subjected to soil and model subjected to both ballast and soil in coherence. A high speed load model (HSLM) was used to create simulation of train passages at different speeds and applied to all cases so that the bridge deck accelerations could be studied. A simplified 2D-model with impedance functions representing the soil-structure interaction was created to validate the results from the detailed 3D-model and for practical design purposes.  The result of this numerical analysis showed that the vertical accelerations were within acceptable levels of the maximum allowed limits given in governing publications. Considering the surrounding soil, the results revealed an increase of the dynamic response in the midspan at resonant frequency. However, it was identified that this behavior is not explained by the influence of soil structure interaction but rather the change in boundary conditions of the end-shields. The same dynamic behavior was identified for the simplified 2D-model, with a slight underestimation of the vertical accelerations at resonance.

The increasing need for High-Speed Railway (HSR) to reduce the travelling time requires increasing research within this field. Bridges are main components of any railway network, including HSR networks, and the optimization of their design for this purpose would contribute to a faster and more cost effective development of the HSR network. The initial investment, the running and maintenance costs of the bridges can be decreased through better understanding of the their dynamic behaviour. This thesis studies the dynamic behaviour of end-shield railway bridges under HSR operation. 2D beam analysis is used to study the effect of the distribution of the train’s axle load. Relatively accurate 3D FE-models are developed to study the effect of Soil-Structure Interaction (SSI) and the dynamic response of the bridges. Modelling alternatives are studied to develop an accurate model. A full scale test of a simply supported Bridge with end-shields using load-controlled forced excitation was performed and the results were used to verify the theoretical models. A manual model updating process of the material properties of the 3D FE-model is performed using FRFs from the field measurements. A Simple 2D model is also developed, where a spring/dashpot system is implemented to simplify SSI, and updated to reproduce the field measured responses. The conclusions of the project emphasize the importance of SSI effects in the dynamic analysis of end-shield bridges for predicting their dynamic behaviour. The conclusions also show that the modelling of the surrounding soil and the assumption of the soil material parameters have significant effect on the dynamic response. Even the boundary conditions, bedrock level and the ballast on the railway track affects the response. The results also show that the bridge’s concrete section behaves as uncracked section under the studied dynamic loading. / <p>QC 20170403</p>

Major cities in Sweden experience a population growth, demanding innovative solutions regarding land exploitation for residential housing. One solution is to build closer to existing railway tracks, however difficulties arise regarding determining traffic induced vibrations from trains. This sometimes results in vibrations being too large in buildings regarding comfort, resulting in expensive measures taken as to reduce the vibrations. The scope of this thesis is to investigate the soil-structure interaction caused by traffic induced vibrations in buildings using ABAQUS FE software, where the aim is to partly investigate how a structure effects surrounding soil, partly to investigate which parameters of a structure has largest favorable impact on foundation vibrations. Major results include that ground vibrations at 2-4 meters parallel to a structure relative to the vibration source remain constant, independent on whether a house is present or not. Further results show that increasing the thickness of the foundation slab has a mitigating effect on the induced vibrations. The main conclusions of this thesis include that quadratic elements are superior to linear elements for dynamic analyses for soil, and that accelerometers should be placed at least 2-4 m next to an existing structure to obtain accurate measurements comparable to if no structure was present. / Större städer i Sverige upplever en befolkningstillväxt, vilket resulterar i att kreativa lösningar måste introduceras gällande markexploatering för bostadshus. En sådan lösning är att bygga närmre befintlig järnväg, dock resulterar detta i svårigheter gällande att kvantifiera magnituden av trafikinducerade vibrationer i byggnadsfundament orsakade av tågtrafik. En konsekvens av detta är att vibrationsnivåerna i husen ibland blir för stora sett till komfortvibrationer, vilket resulterar i att dyra åtgärder måste tas för att minska vibrationerna. Denna avhandling syftar till att genom att använda ABAQUS FE-mjukvara utforska jord-strukturinverkan i hus orsakade av trafikvibrationer. Målet är delvis att undersöka hur byggnation påverkar omgivande markvibrationer, delvis att undersöka vilka parametrar som har störst gynnsam effekt gällande dämpning av trafikinducerade vibrationer. De viktigaste resultaten indikerar att markvibrationer 2-4 meter bredvid ett hus relativt vibrationskällan förblir oförändrade oberoende av om byggnation existerar eller ej, samt att en ökning av tjockleken av grundplattan resulterar i minskade fundamentvibrationer. Slutsatserna som presenteras är flera, däribland att kvadratiska element är mer beräkningseffektiva än linjära element för dynamiska analyser för jord, samt att accelerometrar bör placeras minst 2-4 m bredvid ett befintligt hus för att erhålla mätdata jämförbara med om ett hus inte skulle finnas på platsen.

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Solving radiation shielding problems, i.e. deep penetration problems, is a challenging task from both computation time and resource aspects in field of nuclear engineering. This is mainly because of the complexity of the governing equation for neutral particle transport - Linear Boltzmann Equation (LBE). The LBE includes seven independent variables with presence of integral and differential operators. Moreover, the low successive rate of radiation shielding problem is also challenging for solving such problems. In this dissertation, the Detector Response Function (DRF) methodology is proposed and developed for real-time and accurate radiation shielding calculation. The real-time capability of solving radiation shielding problem is very important for: (1) Safety and monitoring of nuclear systems; (2) Nuclear non-proliferation; and (3) Sensitivity study and Uncertainty quantification. Traditionally, the difficulties of solving radiation problem are: (1) Very long computation time using Monte Carlo method; (2) Extremely large memory requirement for deterministic method; and (3) Re-calculations using hybrid method. Among all of them, the hybrid method, typically Monte Carlo + deterministic, is capable of solving radiation shielding problem more efficiently than either Monte Carlo or deterministic methods. However, none of the aforementioned methods are capable of performing "real-time" radiation shielding calculation. Literature survey reveals a number of investigation on improving or developing efficient methods for radiation shielding calculation. These methods can be categorized by: (1) Using variance reduction techniques to improve successive rate of Monte Carlo method; and (2) Developing numerical techniques to improve convergence rate and avoid unphysical behavior for deterministic method. These methods are considered clever and useful for the radiation transport community. However, real-time radiation shielding calculation capability is still missing although the aforementioned advanced methods are able to accelerate the calculation efficiency significantly. In addition, very few methods are "Physics-based" For example, the mean free path of neutrons are typically orders of magnitude smaller than a nuclear system, i.e. nuclear reactor. Each individual neutron will not travel too far before its history is terminated. This is called the "loosely coupled" nature of nuclear systems. In principle, a radiation shielding problem can be potentially decomposed into pieces and solved more efficient. In the DRF methodology, the DRF coefficients are pre-calculated with dependency of several parameters. These coefficients can be directly coupled with radiation source calculated from other code system, i.e. RAPID (Real-time Analysis for Particle transport and In-situ Detection) code system. With this arrangement, detector/dosimeter response can be calculated on the fly. Thus far, the DRF methodology has been incorporated into the RAPID code system, and applied on four different benchmark problems: (1) The GBC-32 Spent Nuclear Fuel (SNF) cask flooded with water with a $^3$He detector placed on the cask surface; (2) The VENUS-3 experimental Reactor Pressure Vessel (RPV) neutron fluence calculation benchmark problem; (3) RPV dosimetry using the Three-Mile Island Unit-1 (TMI-1) commercial reactor; and (4) A Dry storage SNF cask external dosimetry problem. The results show that dosimeter/detector response or dose value calculations using the DRF methodology are all within $2sigma$ relative statistical uncertainties of MCNP5 + CADIS (Consistent Adjoint Driven Importance Sampling) standard fixed-source calculation. The DRF methodology only requires order of seconds for the dosimeter/detector response or dose value calculations using 1 processor if the DRF coefficients are appropriately prepared. The DRF coefficients can be reused without re-calculations when a model configuration is changed. In contrast, the standard MCNP5 calculations typically require more than an hour using 8 processors, even using the CADIS methodology. The DRF methodology has enabled the capability of real-time radiation shielding calculation. The radiation transport community can be greatly benefited by the development of DRF methodology. Users can easily utilize the DRF methodology to perform parametric studies, sensitivity studies, and uncertainty quantifications. The DRF methodology can be applied on various radiation shielding problems, such as nuclear system monitoring and medical radiation facilities. The appropriate procedure of DRF methodology and necessary parameters on DRF coefficient dependency will be discussed in detail in this dissertation. / Doctor of Philosophy / Since the beginning of nuclear era, enormous amount of radiation applications have been proposed, developed, and applied in our daily life. The radiation is useful and beneficial when they are under control. However, there will be some "unwanted radiation" from these applications, which have to be shielded. For this, radiation shielding has become a very important task. To effectively shield the unwanted radiations, studying the thickness and design of the shields is important. Instead of directly performing experiments, computation is a more affordable and safer approach. The radiation shielding computation is typically an extremely difffficult task due to very limited "communication" between the radiation within the shield and detector outside the shield. In general, it is impractical to simulate the radiation shielding problems directly because the extremely expensive computation resources. Most of interactions of radiation are within the shield while we are only interested in how many of them penetrate through the shield. This is typically called "deep penetration" problems in the radiation transport community.

In vielen industriellen Anwendungen sind Dichtungen im Einsatz. Vergleicht man den Preis mit dem eines Gesamtsystems, in denen Dichtungen verwendet werden, so sind Dichtungen verhältnismäßig günstig. Jedoch führt ein Versagen von Dichtungen meist zu schwerwiegenden Konsequenzen. Dichtungen sind komplexe Subsysteme und ihre Auslegung erfordert umfangreiche Kenntnisse im Bereich Materialmodellierung, Belastung und Versagenskriterien. Die heutige Simulationstechnologie ermöglicht einen parametrischen Workflow für die Berechnung des Verhaltens von Dichtungen mit den auftretenden Effekten wie nichtlinearem Materialverhalten, wechselnden Kontaktbedingungen und Flüssigkeitsunterwanderung bei Druck. Als ein führendes Simulationswerkzeug für diese physikalische Fragestellung wird ANSYS Mechanical für die Auslegung herangezogen. Desweiteren kann das Verständnis für das Produkt erhöht werden, was zu einer Verbesserung der Funktionalität und der Zuverlässigkeit führt. Versuchsdaten können als Spannungs-Dehnungskurven in ANSYS importiert werden, welche das Materialverhalten des hyperelastischen Werkstoffs mit traditionellen Materialmodellen wie Mooney Rivlin, Ogden and Yeoh oder einer neueren Formulierung, der Antwortfunktionsmethode, widerspiegeln. Robuste Kontakttechnologien beschleunigen die Simulation und Entwicklungszeit-Berechnungszeiten und gewährleisten ein genaues Verhalten des Simulationsmodells. Insbesondere bei Dichtungen ist die druckbeaufschlagte Fläche in 2D und 3D Anwendungen von Bedeutung. ANSYS berechnet diese automatisch in Abhängigkeit des aktuellen Kontaktzustandes. Diese benutzerfreundliche Unterstützung führt zu einer höheren Genauigkeit des Simulationsergebnisses, da ein manuelles Schätzen der Druckflächen entfällt. Mit einem parametrischen und durchgängigen Ansatz innerhalb von ANSYS Workbench, beginnend bei der CAD-Geometrie, über die Vernetzung, Material- und Randbedingungsdefinition und Lösung. können eine Reihe von Varianten in kurzer Zeit berechnet werden. Neben einem besseren Verständnis für das Produkt hilft dies dem Ingenieur Änderungen vorzunehmen, was zu exakten und aussagekräftigen Ergebnissen führt. Desweiteren kann der Einfluss von Unsicherheiten berücksichtigt werden, sodass der Berechnungsingenieur fernab von idealen Bedingungen robuste und zuverlässige Dichtungen entwickeln kann.

Perfusion magnetic resonance imaging is modern diagnostic method used mainly in oncology. In this method, contrast agent is injected to the subject and then is continuously monitored the progress of its concentration in the affected area in time. Correct determination of the arterial input function (AIF) is very important for perfusion analysis. One possibility is to model AIF by multichannel blind deconvolution but the estimated AIF is necessary to be scaled. This master´s thesis is focused on description of scaling methods and their influence on perfussion parameters in dependence on used model of AIF in different tissues.

En dosimétrie, la distribution énergétique des photons émis par une source constitue un paramètre incontournable. Dans la gamme des basses et moyennes énergies (i.e. E<150 keV ici), le LNHB possède 5 tubes à rayons X ainsi que des grains de curiethérapie à l’iode 125, présentant des hauts débits de fluence. La détermination du spectre émis par calcul (déterministe ou Monte-Carlo) est limitée, dans la gamme d’énergie considérée, par les incertitudes élevées sur les bases de données ainsi que par les approximations du modèle. La mesure directe avec un détecteur au germanium ultra-pur a donc été retenue, bien que nécessitant de lourds moyens. De plus, le spectre mesuré est le produit de convolution du spectre émis recherché par la réponse du système. Une fois la réponse du détecteur modélisée, il est possible de « déconvoluer» la mesure, i.e. de remonter au spectre réellement émis en corrigeant (par stripping, model-fitting, inférence bayésienne…) les déformations spectrales induites par le processus de détection. Pour la curiethérapie, le modèle de grain-source a ainsi pu être ajusté. Pour les tubes à rayons X, les résultats obtenus avec différents codes Monte-Carlo et 4 logiciels déterministes ont été comparés à un spectre dit de référence obtenu par mesure et déconvolué. Ainsi l’impact sur certaines grandeurs dosimétriques de la méthode utilisée a pu être quantifié. / In the field of dosimetry, the knowledge of the whole photon fluence spectrum is an essential parameter. In the low-to-medium energy range (i.e. E<150 keV), the LNHB possess 5 X-ray tubes and iodine-125 brachytherapy seeds, both emitting high fluence rates. The performance of calculation (either Monte Carlo codes or deterministic software) is flawed by increasing uncertainties on fundamental parameters at low energies, and modelling issues. Therefore, direct measurement using a high purity germanium is preferred, even though it requires a time-consuming set-up and mathematical methods to infer impinging spectrum from measured ones (such as stripping, model-fitting or Bayesian inference…). Concerning brachytherapy, the knowledge of the seed’s parameters has been improved. Moreover, various calculated X-ray tube fluence spectra have been compared to measured ones, after unfolding. The results of all these methods have then be assessed, as well as their impact on dosimetric parameters.

由於住宅價格變動毫無預警制度，人民往往憑著個人主觀的判斷而決定何時購屋或售屋，而此種主觀判斷住宅市場利多及利空的觀念，對住宅市場的供需會產生失衡現象，因此是否可從經濟面的訊息找到住宅價格變動的答案，使住宅價格在尚未變動前，政府即已掌握資訊，提前做好穩定住宅價格的因應對策，使民眾依其需要而購屋，則是本研究之主要目的。 　　本研究從文獻中整理出影響住宅價格變動的七個總體經濟變數，這些總體經濟變數包含工資、物價、所得、貨幣供給額、股價、匯率及利率等，並利用向量自我迴歸模式(VAR)進行實證，以便較客觀的獲得變數間的落後期數及暸解變數間雙向、單向及領先、同步、落後情形，且進一步探討住宅價格與每一個總體經濟變數間影響程度大小及影響情形，以釐清各變數之間的關係。 　　本研究利用VAR模型進行住宅價格與總體經濟變數關係的研究，經由實證，得到下列的結論： 　　一、實證結果方面 　　本研究之實證主要有因果關係檢定與分析、變異數分解之分析及衝擊反應之分析三方面，其實證結果如下所述。 　　（一）因果關係檢定與分析 　　由因果關係檢定與分析中，得到股價、物價、匯率、貨幣供給額及利率均能做為住宅價格變動的領先指標。 　　（二）變異數分解之分析 　　由住宅價格之變異數分解中，得知住宅價格自身的解釋程度僅占三分之一，另三分之二被其他的總體經濟變數所解釋，顯示住宅價格受總體經濟變數的影響相當大；而從其他總體經濟變數之變異數分解中，得知住宅價格變動會干擾到總體經濟變數，而使總體經濟變數受干擾而變動變動。 　　（三）衝擊反應之分析 　　從總體經濟變數對住宅價格的衝擊反應分析圖中可以明顯看出除工資外，其餘總體經濟變數變動對住宅價格造成的衝擊均相當明顯，但匯率及利率對住宅價格的衝擊是負向的。 　　住宅價格對所得、股價、匯率及利率的衝擊相當明顯，而其對匯率的衝擊是負向。 　　二、政策應用方面 政府的決策過程中常會有時間落後的現象，而本研究實證的目的則是要使政府能事先掌握住宅價格的變動，並提前做好穩定住宅價格的因應對策，減少政府決策過程的時間落後現象，而實證結果應用至政策方面的內容則由以下說明之。 　　（一）藉由因果關係檢定與分析的實證內容，可以縮短政府對住宅價格不合理變動問題認定落後的時間。 　　（二）從變異數分解之分析的實證內容中，可以使決策者在解決住宅價格問題時，將行動落後的時間減少。 　　（三）由衝擊反應之分析中，可以使政府在執行穩定住宅價格政策時，將衝擊落後的時間縮小。 / Since there is no alarm system in the change of housing prices, people often decide when to buy or when to sell based on personal and subjective judgement. Such concept to judge subjectively whether the housing market is bull or bear will cause unequilibrium in the supply and demend of the housing market. There it is possible to find out the answers to the change of housing prices from economic side so that the government can have enough information and can be prepared in the reaction to stabilizing the housing prices, and so that the public can buy house according to their needs is the main purpose of this project. 　　Seven variables in macroeconomics influencing the change of housing prices have been taken from reative literature, including wage, commodity price, income, money supply, stock price, exchange rate, and interest rate. VAR has been employed to verify so that the more objective lagging period among variable can be known, and the bi-directional, uni-directional, leading, contemporaneous, and lagging situation among variables can be understood. Furthermore, the degree and the status of influence of each macroeconomic variable to the housing price will be investigated to clarify the relations among the variables. 　　The present project investigate the relations between housing price and macroeconomic variables. We have the following findings: 　　I、In Empirical Study: 　　The empirical study in this project includes causal relation test and analysis, the analysis of variable decompositon, and the analysis of impact response. The results are shown in the following: 　　(I) Causality Test and Analysis 　　In the causality test and analysis, we find out that stock price, commodity price, exchange rate, money supply and interest rate all can be the leading indicators in the change of housing prices. 　　(II) The Analysis of Variable Decomposition 　　It is learned from the variable decomposition of housing prices that housing price can only explain one third of the cause in its change, the other two thirds are explained by other macroeconomic variables. It shows that housing prices are subject to the influence of macroeconomic variables greatly. 　　From the variable decomposition of other macroeconomic variables, we know that the change in housing prices will affect macroeconomic variables so that the macroeconomic variables will change. 　　(III) The Analysis of Impact Response 　　It can be obviously seen from the analysis figure of the impact response of the macroeconomics to housing prices, all macroeconomic variables will cause obvious impact to housing prices expect for wage. However, both exchange rate and interest rate have negative impact to housing prices. 　　Housing prices' impact to income, stock prices, exchange rate and interest rate is quite obvious, among which, the impact to exchange rate is negative. 　　II、Policy Application 　　It is a common phenomenon that there often will be lagging in time in government's decision making. The purise of the empirical study in this project is to let the government to know in advance the change of housing prices and to let the government to know in advance the change of housing prices and to let the government be prepared in the reaction of stabilizing the housing prices to minimize the lagging in the decision making process. The contents of application of the empirical study to policy are explained in the following: 　　(I) With the empirical results of the change of the causality test and analysis, the time for the government to recognize the unreasonable changes in housing prices can be shortened. 　　(II) With the empirical results of the analysis of variable decomposition, the decision makers' lagging in the action responding to housing pricescan be minimized. 　　(III) With the analysis in impact response, the lagging in impact will be minimized when the government executing her housing price stabilizing policy.

HTLV-I is the first discovered human retrovirus and a causative agent of both adult T-cell leukemia (ATL) and HTLV-I-associated myelopathy (or tropical spastic paraparesis) (HAM/TSP). Previous models have been successful in providing insight into the progression of HTLV-I infection. The relative simplicity of HTLV as well as its similarities to HIV and other diseases allow HTLV-I research to have diverse applications. The development of HAM/TSP is precipitated by a CTL immune response. Previous models for CTL response to HTLV-I infection have had relatively simple behaviours. A novel sigmoidal CTL response function results in complex behaviours previously unobserved. We establish the existence of bistability between solutions corresponding to carrier and endemic states. In addition, both super- and sub-critical Hopf bifurcations as well as the resulting stable and unstable periodic solutions are observed. Analytical and numerical results are discussed, as well as the biological consequences of the aforementioned behaviours. / Applied Mathematics