This paper focuses on Austrian outbound foreign direct investment (FDI, measured by sales of Austrian affiliates abroad) in Europe over the period 2009-2013, using a spatial Durbin panel data model specification with fixed effects, and a spatial weight matrix based on the first-order contiguity relationship of the countries and normalised by its largest eigenvalue. Third-country effects essentially enter the empirical analysis in two major ways: first, by the endogenous spatial lag on FDI (measured by FDI into markets nearby the host country), and, second, by including an exogenous market potential variable that measures the size of markets nearby the FDI host country in terms of gross domestic product. The question whether the empirical result is compatible with horizontal, vertical, export-platform or complex vertical FDI then depends on the sign and significance levels of both the coefficient of the spatial lag on FDI and the direct impact estimate of the market potential variable. The paper yields robust results that provide significant empirical evidence for horizontal FDI as the main driver of Austrian outbound FDI in Europe. This result is strengthened by the indirect impact estimate of the mark et potential variable indicating that spatial spillovers do not matter. (authors' abstract)

In recent years there were many debates and different opinions whether R&D spillover effects exist or not. In 1995 Coe and Helpman published a study about this phenomenon, based on a panel dataset, that supports the position that such R&D spillover effects are existent. However, this survey was criticized and many different suggestions for improvement came from the scientific community. Some of them were selected and analysed and finally led to a new model. And even though this new model is well compatible with the data, it leads to different conclusions, namely that there does not exist an R&D spillover effect. These different results were the motivation to run a spatial analysis, which can be done by considering the countries as regions and using an adequate spatial link matrix. The used methods from the field of spatial econometrics are described briefly and quite general, and finally the results from the spatial models (the ones which correspond to the non-spatial ones) are compared with the results from the non-spatial analysis. The preferred model supports the position that R&D spillover effects exist.

La production de protéines recombinantes, d’anticorps, de vaccins, … est de plus en plus réalisée par culture de cellules animales. Le bioréacteur classiquement utilisé en industrie pour réaliser ces cultures est le bioréacteur à cuve agitée. Ce bioréacteur présente un volume important ce qui rend difficile le développement d’un bioréacteur à usage unique dans l’optique de réduire les risques de contaminations entre deux cultures consécutives. L’intensification du procédé et le développement de bioréacteur à usage unique sont donc deux défis intéressants dans la réalisation de cultures cellulaires à l’échelle industrielle. Un bioréacteur particulièrement prometteur pour l’intensification de culture cellulaire est le bioréacteur lit-fixe. Dans cette thèse, nous étudions le bioréacteur lit-fixe à usage unique iCELLis développé par Artelis S.A.<p>Le lit-fixe du bioréacteur iCELLis est composé d’un empilement de porteurs maintenu entre deux grilles perforées. Ces porteurs sont utilisés comme support par les cellules au cours de la culture. Le bioréacteur est équipé d’un système de transfert gaz-liquide par film tombant afin d’oxygéner le milieu de culture en continu. Une pompe centrifuge plongée dans un bac d’immersion assure la circulation du milieu de culture à travers l’ensemble du bioréacteur. Les cultures se déroulent en trois phases :une phase d’adhérence des cellules aux porteurs du lit-fixe, une phase de croissance cellulaire et une phase de production.<p>Les avantages d’un bioréacteur lit-fixe sont nombreux :une concentration cellulaire élevée impliquant une productivité élevée, un petit volume de bioréacteur, une faible exposition des cellules aux contraintes de cisaillement, Les bioréacteurs lits-fixes présentent cependant certains inconvénients qui freinent leur développement à l’échelle industrielle. Le lit-fixe se présente comme un réacteur piston ce qui implique l’apparition de gradients de concentrations de cellule et d’espèces extracellulaires (nutriments et produits) le long du lit-fixe. L’intérieur du lit-fixe est également difficilement accessible au cours de la culture. Le suivi des concentrations de cellules et d’espèces dans cette zone est donc problématique.<p>Une modélisation globale du bioréacteur lit-fixe nous permet de mieux comprendre les différents phénomènes qui prennent place dans le bioréacteur. Grâce à cette modélisation, nous sommes donc capables d’identifier les phénomènes clés contrôlant le procédé et ainsi fournir des pistes de travail pour l’optimisation et la montée en échelle du bioréacteur, ceci sur base de critères rationnels.<p>Nous choisissons de développer un modèle à compartiments du bioréacteur lit-fixe. Dans ce type de modèle, le bioréacteur est représenté par un réseau de compartiments interconnectés. Nous définissons trois compartiments :un premier pour la pompe, un deuxième pour les cellules et le lit-fixe, et un troisième pour le système de transfert gaz-liquide.<p>Pour le premier compartiment, nous souhaitons caractériser divers paramètres identifiés comme pertinents pour une sélection adéquate de la pompe. Dans cette thèse, nous présentons une méthode pour caractériser ces paramètres pour une pompe de référence (celle du bioréacteur iCELLis) et pour une pompe en similitude géométrique à la pompe de référence (dans le but d’étudier la montée en échelle).<p>La pompe de référence est étudiée numériquement (grâce aux logiciels Gambit 2.4 et Fluent 6.3) et expérimentalement. Nous mettons en évidence les liens entre les paramètres de la pompe déterminés numériquement et ceux déterminés expérimentalement. Ces liens définissent notre modèle. En intégrant au modèle les résultats de la simulation numérique de l’écoulement du milieu de culture dans le bac d’immersion contenant la pompe en similitude géométrique à la pompe de référence, nous déterminons entièrement les paramètres recherchés de la seconde pompe sans avoir recours à un prototype. Ceci permet donc de tester différentes échelles avant de choisir la version finale de la seconde pompe.<p>Le deuxième compartiment du modèle caractérise les cellules et le lit-fixe. La sélection de certains paramètres opératoires dépend du métabolisme cellulaire. Nous souhaitons développer un outil de surveillance en ligne de l’évolution des concentrations de certaines espèces extracellulaires sur base de la connaissance de la concentration cellulaire dans le bioréacteur. Cet outil est développé sur base d’un modèle structuré du métabolisme des cellules animales. Dans un tel modèle, nous établissons des bilans de matière sur les espèces extra- et intracellulaires en considérant les voies métaboliques intracellulaires. Un paramètre requis pour l’emploi de cet outil est la connaissance de la concentration cellulaire au cours de la culture. Or, la surveillance de cette concentration est l’un d’un problème évoqué dans les bioréacteurs lits-fixes. Nous développons donc un modèle ségrégé de culture cellulaire en bioréacteur lit-fixe. Dans ce modèle, nous considérons l’entièreté du lit-fixe. Le modèle comprend différentes populations de cellules :les cellules en suspension dans le milieu au début de la culture et les cellules adhérentes au lit-fixe. Le modèle inclut une distribution spatiale de la concentration d’espèces extracellulaires dans le lit-fixe. Par conséquent, le modèle rapporte les gradients potentiels de concentration de cellules et d’espèces extracellulaires dans le lit-fixe.<p>Le troisième compartiment du modèle du bioréacteur caractérise le système de transfert gaz-liquide. L’oxygénation est très souvent un paramètre clé dans la conception d’un bioréacteur. Dans le bioréacteur iCELLis, le système de transfert gaz-liquide est un film liquide tombant turbulent. Dans cette thèse, nous proposons une méthode pour caractériser le transfert d’oxygène à travers ce type de film tombant. Notre méthode, basée sur une approche numérique (grâce à Gambit 2.4 et Fluent 6.3), est scindée en deux parties. Premièrement, nous calculons la forme de l’interface gaz-liquide. Une simulation de l'écoulement est réalisée avec le modèle Volume of Fluid (VOF). A partir de cette simulation, la forme de l'interface est traquée. Deuxièmement, la forme de l'interface est générée dans un nouveau domaine de calcul afin de simuler le transfert d’oxygène. Grâce à cette seconde simulation, le coefficient de transfert d’oxygène de la phase gazeuse vers le milieu de culture est déterminé. Grâce à notre méthode, nous caractérisons ce coefficient pour différentes conditions opératoires. Nous étudions notamment l’influence du débit et de la température du milieu de culture sur le coefficient de transfert d’oxygène. / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished

Abstract The aims of this study were to evaluate the treatment need of fixed bridges according to the distribution of pontics in dentition in different age groups, and to investigate the primary and late complications and survival of the conventional fixed metal ceramic prostheses, as well as patients' satisfaction with the prosthetic treatment. The whole material consisted of the patients treated with fixed metal ceramic prostheses by undergraduate students at the Institute of Dentistry during the years 1984 - 1996. There were altogether 772 patients, 460 women (60 %) and 312 men (40 %). Their mean age was 47 years (23 - 81 years). Altogether 944 single metal ceramic crowns and 543 fixed bridges (1374 abutments and 807 pontics) were prepared. It can be concluded that the fixed bridges are most often prepared to replace upper first premolars and lower first molars also in the future. The most usual primary complications related to fixed bridges occurred during preprosthetic endodontic treatment of abutment teeth and during the preparation of the root canals. Previous restoration of the prepared tooth does not have any marked effect on the prognosis of single crowns with dowels, although anatomically complicated upper lateral incisors and upper first premolars need special attention in the treatment planning. Patients were satisfied with aesthetics and function of the fixed metal ceramic prostheses. Late complications found in clinical examinations were few, and the survival rate for the fixed metal ceramic bridge prostheses was calculated to be 84 % after 10 years, long fixed bridges having a lower survival than the shorter ones. The treatment need for conventional fixed bridges seems to be highest among patients over 50 years of age in the future. Age does not influence the longevity of the fixed prostheses, but basic circumstances of the mouth, especially low secretion of saliva affected by diseases and/or medications and high scores of lactobacilli and streptococcus mutans of the saliva seem to decrease the survival.

Abstract Digital delta-sigma modulators are used in a broad range of modern electronic sub-systems, including oversampled digital-to-analogue converters, class-D amplifiers and fractional-N frequency synthesizers. This work addresses a well known problem of unwanted spurious tones in the modulator’s output spectrum. When a delta-sigma modulator works with a constant input, the output signal can be periodic, where short periods lead to strong deterministic tones. In this work we propose means for guaranteeing that the output period will never be shorter than a prescribed minimum value for all constant inputs. This allows a relationship to be formulated between the modulator’s bus width and the spurious-free range, thereby making it possible to trade output spectrum quality for hardware consumption. The second problem addressed in this thesis is related to the finite accuracy of frequencies generated in delta-sigma fractional-N frequency synthesis. The synthesized frequencies are usually approximated with an accuracy that is dependent on the modulator’s bus width. We propose a solution which allows frequencies to be generated exactly and removes the problem of a constant phase drift. This solution, which is applicable to a broad range of digital delta-sigma modulator architectures, replaces the traditionally used truncation quantizer with a variable modulus quantizer. The modulus, provided by a separate input, defines the denominator of the rational output mean. The thesis concludes with a practical example of a delta-sigma modulator used in a fractional-N frequency synthesizer designed to meet the strict accuracy requirements of a GSM base station transceiver. Here we optimize and compare a traditional modulator and a variable modulus design in order to minimize hardware consumption. The example illustrates the use made of the relationship between the spurious-free range and the modulator’s bus width, and the practical use of the variable modulus functionality.

Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第17563号 / 工博第3722号 / 新制||工||1567(附属図書館) / 30329 / 京都大学大学院工学研究科原子核工学専攻 / (主査)教授 森 義治, 教授 伊藤 秋男, 教授 中島 健 / 学位規則第4条第1項該当

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Prediction markets provide a promising approach for future event prediction. Most existing prediction market approaches are based on auction mechanisms. Despite their theoretical appeal and success in various application settings, these mechanisms suffer from several major drawbacks. First, opinions from experts and amateurs are treated equally. Second, continuous attention from participants is assumed. Third, such mechanisms are subject to various forms of market manipulation. To alleviate these limitations, we propose to employ the classic fixed odds betting as an alternative prediction market mechanism. We build a structural model based on a belief-decision framework as the event probability estimator. This belief-decision framework models bettors' beliefs with mixed beta distributions and bettors' decisions with prospect theory. A maximum likelihood approach is applied to estimate the model parameters. We conducted experiments on three real-world betting datasets to evaluate our proposed approach. Experimental results show that fixed odds betting based prediction outperforms the reduced form models based on odds and betting results, and achieves a comparable performance with auction-based prediction markets. The results suggest the possibility of employing fixed odds betting as a prediction market in a variety of application contexts where the assumptions made by auction-based approaches do not hold.

Doctor of Philosophy / Department of Economics / Lloyd B. Thomas Jr / Dennis L. Weisman / This dissertation has focused primarily on the relationship between aggregate private output and a measure of the public fixed capital stock for the U.S. economy using two different approaches for the years 1947-2005. The study starts with a brief survey of the existing literature on the relationship between private output and public capital and continues with an analysis of data on some macroeconomic variables related to private output and public capital. It employs a production function approach to provide empirical estimates and analyze its econometric problems, and continues with a vector autoregression (VAR) model. It uses two criteria, the Akaike Information Criterion and the Schwartz Bayesian Criterion, to compare the performance of the two models tested. There are several differences between this study and the existing literature. The most important difference is that each of the other studies uses only a single approach to analyze the relationship between the public capital stock and private economic growth while this study uses two different methodologies to analyze the same relationship and tests the two models using the same aggregate macroeconomic annual data on the U.S. economy from 1947 to 2005. This study represents the first attempt to provide estimates of the elasticities of private output with respect to the private capital stock, private labor stock, public nonmilitary capital stock, and public core infrastructure capital stock by employing two different approaches so that the comparison of the elasticities resulting from the two different approaches can be most meaningful. Moreover, this study also represents the first attempt to provide estimates of the marginal products of the above four inputs. Second, the studies that employ a production function approach are ad hoc and so is the production function approach of this study, but the production function approach section of this study is the only one having an explicit capital evolution equation for both the private and the public capital stock. All of the other studies using annual data use aggregate macroeconomic data on related variables for less than thirty years while this study employs aggregate data from 1947 to 2005 (fifty nine years). Lastly, the other production function studies are incomplete in the sense that they either do not attempt to deal with some major econometric problems such as a common trend (resulting in a spurious correlation) and the direction of the causation or when they do acknowledge major econometric problems, they do not do anything to correct them. This study, on the other hand, will try to detect major econometric problems. Once the problem is detected, the study will employ measures to deal with the problem. Major findings of this study are as follows. First, the causation runs from the public fixed capital stock to private output rather than in the other direction. Second, most of the studies in the existing literature report a positive impact of the private fixed capital stock on private output that is too small to be credible, whereas they report a positive impact of the public fixed capital stock on private output that is too large to be credible. However, the estimates of this study suggest not only a positive impact of the public capital stock on private output that seems credible but also a positive and very large impact of the private capital stock on private output. Third, the results of several joint hypothesis tests conducted show that there is enough sample evidence to claim that not only that the private sector operates under constant returns to scale in all inputs, private and public, for the years 1947-2005 but also that the private fixed capital stock is more important to the aggregate private production process than either of the two measures of the public fixed capital stock.

The South African fixed interest rate market has historically had very little liquidity beyond 15 - 20 years. Most financial institutions are currently prepared to quote and trade interest rate risk up to a maximum term of 30 years. Any trades beyond 30 years usually attract very onerous spreads and raise relevant questions regarding an appropriate level of mid-rates. However, there are many South African entities whose business involves taking on exposure to interest rates beyond 30 years, such as life insurance companies and pension funds. These entities have historically used very traditional approaches to hedging their interest rate exposures across the whole term structure and have typically done little to gain any further protection. We can generalise the problems faced by any entity exposed to long term interest rate risk in South Africa: 1. The inadequacy of traditional matching methods (i.e. immunisation and bucketing) to cope with the long term interest rate risks. 2. The non-observability of interest rate data beyond the maximum term in the yield curve. Associated with this is the inability to adequately quantify interest rate risk. 3. The lack of liquidity in long term interest rate markets. Associated with this is the inability to adequately hedge long term interest rate risk. We examine various traditional approaches to matching / hedging interest rate risk using information available at observable / tradable terms on the nominal yield curve. We then look at the reasons why these approaches are not suitable for hedging long term interest rate risk. Some modern methods to forecast and hedge long term interest rate risks are then examined and the possibility of their use in managing long term interest risk is explored. On the back of these investigations, we propose a number of possible yield curve extrapolation procedures and methodology for performing calibrations. Using some general theoretical hedging results, we perform a case study which analyses the performance of various theoretical hedges over a historical period from October 2001 to March 2007. The results indicate that extrapolation and hedging of the yield curve is able to significantly reduce Value-At-Risk of long term interest rate exposures. A second case study is then performed which analyses performance of the various theoretical hedges using out-of-sample simulated yield curve data. We find that there appears to be a significant benefit to the use of yield curve extrapolation techniques, specifically when used in conjunction with a hedging strategy. In some cases we find that the more simple extrapolation techniques actually increase risk (significantly) when used in conjunction with hedging. However, for some of the more advanced techniques, risk can be significantly reduced. For an entity looking to deal with long term interest rate risk, we find that the choice of extrapolation technique and hedging strategy go hand-in-hand. For this reason the cost of hedging and reduction in risk are strongly correlated. The results we obtain suggest that it is necessary to weigh the benefits against the cost of hedging. Further, this cost seems to increase with increasing reduction in risk. The research and results presented here are related to those in the paper Long Term Forecasting and Hedging of the South African Yield Curve presented by Thomas and Maré at the 2007 Actuarial Convention in South Africa. Copyright / Dissertation (MSc)--University of Pretoria, 2009. / Mathematics and Applied Mathematics / unrestricted