No description available.

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Because of the accuracy and ease of implementation, the Monte Carlo methodology is widely used in the analysis of nuclear systems. The estimated effective multiplication factor (keff) and flux distribution are statistical by their natures. In eigenvalue problems, however, neutron histories are not independent but are correlated through subsequent generations. Therefore, it is necessary to ensure that only the converged data are used for further analysis. Discarding a larger amount of initial histories would reduce the risk of contaminating the results by non-converged data, but increase the computational expense. This issue is amplified for large nuclear systems with slow convergence. One solution would be to use the convergence of keff or the flux distribution as the criterion for initiating accumulation of data. Although several approaches have been developed aimed at identifying convergence, these methods are not always reliable, especially for slow converging problems. This dissertation has attacked this difficulty by developing two independent but related methodologies. One aims to find a more reliable and robust way to assess convergence by statistically analyzing the local flux change. The other forms a basis to increase the convergence rate and thus reduce the computational expense. Eventually, these two topics will contribute to the ultimate goal of improving the reliability and efficiency of the Monte Carlo criticality calculations.

We study weak convergence of sequences in Banach spaces. In particular, we compare the notions of weak and norm convergence. Although these modes of convergence usually differ, we show that in ℓ¹ they coincide. We then show a theorem of Rosenthal's which states that if {𝓍ₙ} is a bounded sequence in a Banach space, then {𝓍ₙ} has a subsequence {𝓍'ₙ} satisfying one of the following two mutually exclusive alternatives; (i) {𝓍'ₙ} is weakly Cauchy, or (ii) {𝓍'ₙ} is equivalent to the unit vector basis of ℓ¹.

Network Convergence or Divergence, what is it, and which are the most likely developments? Today, a much talked about area of telecommunications is the move toward the IP Multimedia Subsystem (IMS), and with it the introduction of IP-based communication in both Public Land Mobile Networks and Public Switched Telephony Networks. This thesis attempts to show whether these two networks will converge with each other and with the Internet in the future - based upon the existence of a few important prerequisites in terms of standards and protocols, whilst divergence in the networks could result if technical and economical obstacles are difficult to circumvent or to exclude from future networks. The major drivers for convergence include the existence of standards for packet-based transmission over a wide variety of underlying networks, the existence of services that make use of these underlying networking protocols, and ultimately also the existence of devices that can use the new features of a converged network architecture. The focus is on the impact convergence services or offerings may have on handsets; specifically which protocols need to be supported, as well as those hardware and software requirements that need to be catered for to enable convergence in the handset sector. The thesis concludes with a summary of the most important factors for convergence in future mobile handsets. / Nätkonvergens eller divergens, vad är det egentligen, och var är utvecklingen på väg? Idag talas det mycket om inom telekommunikationsbranchen om steget till IMS (IP Multimedia Subsystem), och i med det övergången till uteslutande IP-baserad kommunikation i både Public Land Mobile Networks och Public Switched Telephony Networks. Jag ämnar i den här framställningen visa att konvergens mellan dessa två nät samt ett tredje; Internet är avhängigt av ett par viktiga grundförutsättningar, som existensen av protokoll och standarder som främjar konvergens, medan en divergerande utveckling är resultatet av tekniska och ekonomiska förutsättningar som är svåra att kringgå i framtida nät. De stora drivkrafterna för konvergens är existensen av standarder och protokoll för paketbaserad överföring av data över skiftande nätarkitekturer, existensen av tjänster som stödjer dessa protokoll, och slutligen användarterminaler som förmår utnyttja dessa tjänster utvecklade för en konvergerande nättopologi. Fokus för min rapport är på det stöd som behövs i terminalerna för att en sådan här utveckling ska kunna äga rum. Kapaciteten i form av protokoll som dessa terminaler måste stödja, samt vilka hård- och mjukvarukrav som måste uppfyllas kommer också att behandlas. Slutligen kommer jag att framställa en sammanfattning av vad jag anser vara de viktigaste faktorerna i framtida terminaler för att driva den här utvecklingen.

This dissertation poses the question of whether there is a relationship between the speed of convergence of globalisation and the speed of convergence of GDP per capita. Firstly, the concepts of globalisation and real convergence and their relationship are thoroughly explained from both the theoretical and empirical point of view. And secondly, the answer to the question comes in the form of beta and sigma convergence analysis of this relationship. Thirdly, the analysis splits the countries into two groups (developed and developing countries) and finds interesting but ambiguous results in their comparison. Finally, in order to correctly interpret the results of absolute and conditional beta and sigma convergence, their theoretical and empirical overview is discussed in depth. The dissertation concludes by providing some answers to the initial question for every particular analysis. Namely, it shows that this relationship is indeed very ambiguous.

No description available.

This thesis mainly deals with questions concerning the convergence of some sequences of elliptic and parabolic linear and non-linear operators by means of G-convergence and homogenization. In particular, we study operators with oscillations in several spatial and temporal scales. Our main tools are multiscale techniques, developed from the method of two-scale convergence and adapted to the problems studied. For certain classes of parabolic equations we distinguish different cases of homogenization for different relations between the frequencies of oscillations in space and time by means of different sets of local problems. The features and fundamental character of two-scale convergence are discussed and some of its key properties are investigated. Moreover, results are presented concerning cases when the G-limit can be identified for some linear elliptic and parabolic problems where no periodicity assumptions are made.

In 1993 the internal market within the European Union was formed and ensured free movement of goods, services, capital and people. This led to the removal of trade barriers between members of the European Union. When opening up for competition, price differences between countries decreased and more jobs were created. A single currency was introduced by eleven countries in 1999 with the goal of reducing transaction costs, eliminating exchange rate risk and to further simplify trade. In 2001 Greece joined the collaboration and introduced the euro. With a single currency, price differences are expected to decrease. The aim of this study is to investigate whether a common currency has had a significant effect on reducing price dispersion or not. Two types of convergence are tested, beta and sigma convergence. 21 different product groups are included in this study and are sorted after the speed of convergence. All of the 27 EU member states are included and divided into two groups, one euro group and one non-euro group. We also examine if differences in productivity can explain price convergence. The results indicate that the introduction of a common currency did not decrease price dispersion within the majority of product groups. For the product groups in which price convergence are evident, only one product group within the euro countries and one product group within the non-euro countries have proven to be significantly positive in terms of differences in productivity.

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第19468号 / 理博第4128号 / 新制||理||1594(附属図書館) / 32504 / 京都大学大学院理学研究科数学・数理解析専攻 / (主査)准教授 矢野 孝次, 教授 上田 哲生, 教授 重川 一郎 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM