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京都大学 / 新制・課程博士 / 博士(工学) / 甲第23860号 / 工博第4947号 / 新制||工||1773(附属図書館) / 京都大学大学院工学研究科都市社会工学専攻 / (主査)教授 岸田 潔, 教授 三村 衛, 教授 木村 亮 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

Direct ethanol fuel cells are of interest due to the high energy density, ease of distribution and handling, and low toxicity of ethanol. Difficulties lie in finding a catalyst that can completely oxidize ethanol and resist poisoning by intermediate reaction species. Degradation of the catalyst layer over time is also an issue that needs to be addressed. In this work, niobium doped-titanium dioxide (Nb-TiO2) is investigated as a platinum (Pt) support due to its increased resistance to corrosion compared to the common catalyst support, carbon. It has also been seen in the literature that TiO2 is able to adsorb OH and assist in freeing Pt sites by further oxidizing COad to CO2 and thereby increasing the catalytic activity of catalysts toward ethanol oxidation. The TiO2 support is mixed with carbon, forming Nb-TiO2-C, in order to increase the conductivity throughout the support. The electrochemical activity and direct ethanol fuel cell (DEFC) performance of this novel catalyst is investigated and compared to that of two common catalysts, carbon supported Pt (Pt/C) and carbon supported platinum-tin (PtSn/C). While the conductivity of the Pt/Nb-TiO2-C electrodes was low compared to that of the carbon supported electrodes, the overall catalytic activity and performance of the TiO2 supported catalyst was comparable to that of the Pt/C catalyst based on the electrochemically active surface area. / Master of Science

La « vision » à travers les milieux opaques (murs, cloisons, décombres, ou plus généralement tout milieu qui occulte la vision humaine) est l’un des problèmes clefs du contrôle et de la sécurité. Il apparaît à l’heure actuelle un réel besoin de disposer de dispositifs d’observation à travers ces milieux pour des applications tant militaires (lors des assauts, des prises d’otages, etc.) que civiles (recherche de personnes enfouies dans des décombres, dans un incendie, etc). Les avancées sur cette problématique ont conduit à mettre en place des systèmes radars à très courte portée, opérationnels pour la détection et le tracking de personnes dans des environnements simples. Cependant ils nécessitent que les cibles soient en déplacement afin de les différencier des objets statiques. Cette limitation constitue un défaut majeur pour un certain nombre de scénarii réels où des personnes, par stratégie ou par contrainte, restent immobiles. Ces travaux de thèse visent à explorer les mécanismes de détection de personnes statiques par le biais de leurs micro-mouvements, e.g. des mouvements induits par le thorax lors de la respiration. Nous avons étudié - d’un point de vue théorique - les principes physiques sous-jacents à la détection de ces micro-mouvements par radar UWB impulsionnel à partir du mécanisme Doppler impulsionnel. Ce dernier s’appuie sur des mesures consécutives des phases des impulsions réfléchies. La compréhension de ce phénomène a permis de définir une architecture radar impulsionnelle et de la positionner, en termes de contributions, au regard des différents radars UWB proposés dans la littérature : le FMCW et le radar de bruit. Deux dispositifs radars ont servi de support à ce travail. Le premier, de type démonstrateur académique, repose sur l’utilisation d’un oscilloscope rapide pour numériser les impulsions UWB de 3 à 6 GHz de bande. Il a permis de mettre en place une chaîne de traitement complète de vision à travers les murs. Le second dispositif est un prototype radar développé autour d’une plateforme de numérisation ultra-rapide (100 Gsps par échantillonnage équivalent) de fréquence de rafraîchissement très élevée (100 Hz). Il est construit autour d’un FPGA, d’un ADC rapide (1,25 GHz) et d’un T&H très large bande (18 GHz). Il permet ainsi la détection des micro-mouvements par traitement Doppler impulsionnel. / "Vision" through opaque environments (walls, partitions, rubble, or any environment that obscures human vision) is one of the key issues of control and security. Advances on this issue have led to operational shortrange radar systems for people detection and tracking in simple environments. However, most of them require the targets to move in order to differentiate them from static objects. This requirement constitues a major shortcoming for a certain number of real scenarios where people, by strategies or by constraints, remain motionless. Hence, this thesis aims to explore the mechanisms of detection of static people through their micro-movements, e.g. movements induced by the thorax during breathing. We have studied - from a theoretical point of view - the physical principles underlying the detection of these micro-movements by pulsed UWB radar with the pulsed Doppler phenomenon, which relies on consecutive measurements of the reflected pulses phases. The understanding of this phenomenon made it possible to define a radar architecture and to position it, in terms of contributions, with regard to the different UWB radars proposed in the literature : the FMCW and the noise radar. Two radar devices served as support for this work. An academic demonstrator based on the use of a fast oscilloscope to digitize the pulses. It allowed to set up a complete processing chain for the application of vision through the walls. The second device is a radar prototype developed around a high-speed scanning platform (100 Gsps perequivalent sampling) with a very high refresh rate (100 Hz). This prototype is built around an FPGA, a fast ADC (1.25 GHz) and a very wide band T&H (18 GHz). This thereby enables to detect micro-movements by pulsed Doppler processing.

This paper investigates the long-run market effects of open market share repurchase programs, specifically focusing on the influence of firm size (market capitalization) and market-to-book ratio on long-run abnormal returns. The study utilizes data from financial databases, including Nasdaq Stockholm and Eikon, as well as information from initiation announcements and other publicly available documents provided by firms listed on the Stockholm Stock Exchange from 2015 to 2022. The findings of the study reveal that the completion of open market repurchase programs does not exhibit a significant impact on the long-term abnormal return of Swedish firms. Additionally, the study indicates that firm size and market-to-book ratio do not exert a substantial influence on the long-run abnormal return. Previous studies on the subject all show a positive abnormal return associated with the announcement of open market share repurchase program. However, this study diverges from previous research by focusing on the impact after the completion date. Consequently, it can be concluded that there is no significant effect on the long-run abnormal return following the completion of an open market share repurchase program, as the market has already incorporated the impact during the announcement phase, thereby reflecting it in the stock price at the completion date. / I början av 2000-talet blev det lagligt för svenska börsnoterade bolag att köpa tillbaka sina egna aktier. Lagändringen medförde en ny möjlighet för företag att föra tillbaka överskottslikviditet tillaktieägarna. Flertalet svenska och internationella studier har dokumenterat marknadens reaktion vid annonserandet av ett aktieåterköpsprogram, denna studie är först med att undersökamarknadsreaktionen efter avslutade aktieåterköpsprogram. I uppsatsen undersöks sambandet mellan avslutade aktieåterköpsprogram och avvikelseavkastning på lång sikt genom Buy-and-hold-abnormal-return (BHAR). Uppsatsen fokuserar på företag noterade på Nasdaq Stockholm, vilka genomfört minst ett aktieåterköpsprogram under perioden 2015–2022. Studien syftar till att undersöka marknadsreaktionen efter avslutade återköpsprogram på den svenska marknaden. Därtill är syftet att undersöka hur market-to-book kvoten (M/B) och börsvärdet (BV) påverkar avvikelseavkastningen efter avslutat aktieåterköpsprogram på 3, 6 och 12 månaders sikt.Studien har samlat in information och data över återköpen genom Nasdaq, Eikon Refinitiv samt företagens finansiella rapporter och pressmeddelanden. Studiens resultat dokumenterar att det inte finns några signifikanta samband mellan avslutade aktieåterköpsprogram och företags BHAR på3,6 och 12 månaders sikt. Vidare kunde inga statistiskt signifikanta samband säkerställas mellanföretagens M/B kvot respektive börsvärde och BHAR.I slutsatsen diskuteras skillnaden mellan tidigare studiers resultat och resultaten från denna uppsats.Tidigare studier dokumenterar en signifikant positiv avvikelseavkastning, något som skiljer sig från resultaten i denna uppsats. En möjlig förklaring till skillnaden i resultaten är att de tidigare studierna utgår från dagen då aktieåterköpsprogram annonseras. Den marginella avvikelseavkastning i denna studie kan förklaras genom att marknadens reaktion främst sker vid annonseringen av aktieåterköpsprogrammet, och att reaktionen redan prisats in vid tidpunkten för avslutat aktieåterköpsprogram. Resultatet är i linje med tidigare studier på ämnet som visar att den positiva avvikelseavkastning kan kopplas till signalteorin. Studiens resultat kan användas som underlag för att bygga ytterligare kunskap om aktieåterköpsprogram på den svenska marknaden.

Approved for public release; distribution is unlimited. / The purpose of this research is to examine the medical management process of placing and monitoring active duty fleet enlisted personnel in a temporary medical duty status and its impact on fleet readiness. Due to the variety of medical categories this research focuses primarily on personnel placed in Temporary Limited Duty and Medical Hold. Personnel in medical status "limbo" decrease readiness and cost the Navy millions of personnel dollars each year. The study highlights improvements in communication, education and training at all levels of the organization based on observations from the fleet and medical communities. This research is intended to provide stakeholders with a matrix for decision-making and provide guidance on the various temporary medical status categories and recommends design changes to the current Temporary Limited Duty Process. / Lieutenant, Medical Service Corps

Diese Arbeit besteht aus drei zusammengehörigen Essays, die eine theoretische Grundlage für Untersuchungen multilateraler Verhandlungen und strategischer Investitionen in drei unterschiedlichen Umgebungen liefert. Die vorgestellten Methoden werden angewandt um Entwicklungen in der eurasischen Gasversorgung zu analysieren. Der erste analytische Teil befasst sich mit multilateralen Verhandlungen zwischen Russland und den Transitstaaten für sein Gas, namentlich: Ukraine, Weißrussland und Polen. Es wird angenommen dass die beteiligten Länder heterogen sind und dass einige von ihnen nicht die Fähigkeit besitzen langfristige Zusagen zu machen. Wir wenden ein zweistufiges spieltheoretisches Konzept an um Verzerrungen in Investitionen in das Pipeline System, welches russisches Gas nach Westeuropa transportiert, zu analysieren. Unsere qualitative und quantitative Analyse liefert eine strategische Begründung für den Überschuss an gebauten Kapazitäten und erklärt Überinvestitionen in einige Teilstrecken und Unterinvestitionen in andere als ein Versuch ein Kräftegleichgewicht zu erzeugen. Der zweite Teil beschäftigt sich mit multilateralen Verhandlungen und der Etablierung von Bündnissen in der Gegenwart von externen Effekten. Wir untersuchen ob das Szenario zweier konkurrierender Versorgungsketten, nämlich der russischen und der kaspischen, wahrscheinlich ist oder ob sich eher ein Monopol in der Versorgung herausbildet. Im Besonderen gehen wir auf die Fragestellung ein, wie die Verhandlungsmacht der Beteiligten in diesem Netzwerk von der Struktur des bestehenden Netzwerks und seiner möglichen Änderungen abhängt. Wir zeigen auf, warum die Spieler im Gleichgewicht eine große Koalition bilden. Die dritte Studie richtet sich auf die Formation von Koalitionen in einem Umfeld mit verzögerten externen Effekten. Indem wir ein zweistufiges Spiel benutzen, untersuchen wir, wie die Unfähigkeit der Spieler zu einem langfristigen geteilten Gewinn beizutragen zu strategischen Verzerrungen in Investitionen führen kann. Wir finden heraus, dass Unter- und Überinvestitionen in der Zukunft wahrscheinlich sind, wenn die Spieler nicht in der Lage sein werden langfristige Beziehungen miteinander einzugehen. / This thesis consists of three related essays, which develop the framework to study multilateral bargaining and strategic investments under three different environments. The introduced novel methodologies are applied to analyze developments in the Eurasian gas supply chain. The first analytical part of the thesis concerns multilateral bargaining Russia and transiters for its gas, Ukraine, Belarus, and Poland. The players are assumed to be heterogeneous, some lacking the ability to make long--term commitments. We apply a two stage game to analyze distortions of investments into the pipeline system supplying Russian natural gas to Western Europe. Our qualitative and quantitative analysis provides a strategic rational behind excess capacities, which were built, and explains overinvestment on some tracks and underinvestment on others as an attempt to create countervailing power. The second part of the thesis deals with multilateral bargaining and coalition formation issues in the presence of externalities. We study whether two competing supply chains, Russian vs. Caspian, are likely to be formed or monopoly supply will be organized. We quantify the strategic value of different investment options. In particular, we examine how the bargaining power of the network players depends on the architecture of the existing network and its possible extensions. We show why the players form a grand coalition in equilibrium. The third study focuses on coalition formation and bargaining in the environment with externalities under the hold-up. Using a two stage game we study how the inability of players to commit to long-term profit sharing may lead to strategic distortions in investments. We find that underinvestment and overinvestment are likely to happen in the future, if the players will not be able to build stable long-term relation. The main contribution of the work is in developing a new methodology to study multilateral bargaining and strategic investment problems and in confronting the theory with the real world experience.

I investigate a simple merger arbitrage strategy with a focus on middle-market companies. I estimate [-1, 1] buy-and-hold abnormal returns (BHARs) and long-run BHARs of prospective middle-market acquirers after they announce an acquisition and test whether [-1, 1] BHARs are predictive of subsequent long-run holding period returns (HPRs) and long-run BHARs. The [-1, 1] BHARs are calculated for 57 acquiring companies, and then separated into two equal-weight portfolios: one of positive [-1, 1] BHARs (referred to as the long portfolio) and one of negative [-1, 1] BHARs (referred to as the short portfolio). I then calculate the HPR and long-run BHARs over the following time horizons: [2, 22], [2, 43], [2, 64], [2, 127], and [2, 253]. I perform a Student’s t-test comparing the means of the HPRs of the two portfolios and find that the long and short [2, 22] and [2, 64] HPRs have statistically different mean returns. Similarly, I perform a Student’s t-test comparing the means of the BHARs of the two portfolios and find that the difference in the means are not statistically significant. I also regress the different long-run BHARs on [-1, 1] BHARs, adjusted [-1, 1] BHARs, and normalized [-1, 1] BHARs. Adjusted [-1, 1] BHARs are adjusted for the effects of known predictive factors found in prior literature such as the type of payment. For example, if the type of payment is cash, 2.40 percentage points of the [-1, 1] BHAR is attributed to the cash payment. Normalized [-1, 1] BHARs divide each [-1, 1] BHAR by each security return’s standard deviation over the following trading days: [-22, -2]. I find [-1, 1] BHARs and adjusted [-1, 1] BHARs of middle-market lack statistically significant effects on long-run BHARs over the [2, 22], [2, 43], [2, 127], and [2, 253] horizons. [-1, 1] BHARs and adjusted [-1, 1] BHARs of middle-market firms have statistically significant effects on [2, 64] BHARs. Therefore, a possible merger arbitrage strategy may exist for predicting BHARs for the [2, 64] horizon. The strategy consists of an investor going long on all acquirers that have a positive [-1, 1] BHAR and short on all acquirers that have a negative [-1, 1] BHAR over the following trading days: [2, 64]. After the [-1, 1] BHARs are normalized, however, the normalized [-1, 1] BHARs are no longer statistically significant when predicting any long-run BHAR. On the whole, I find the Efficient Market Hypothesis – which states that the market efficiently prices the information released into the market after an acquisition announcement – is correct, at least with respect to the information contained in [-1, 1] BHARs.

The Canadian canola breeding sector met a transition from publicly funded breeding research to large private investments in research and development (R&D). The increasing use of biotechnology tools in the mid 1990s made the assignment of plant ownership technically possible while the legislative safeguards that were put in place during the same period enabled owners to take juristic actions against potential infringers. Today, canola breeding sector is dominated by large multinational firms. The generation of proprietary knowledge in the canola breeding sector has caused a freedom to operate issue. Private and public firms conducting canola R&D are seriously concerned about their ability to gain and preserve access to key technologies in an IPR world. <p>This thesis uses the tragedy of the anticommons framework to analyze the consequences of increased intellectual property protection in the canola breeding sector. Theory suggests that when a common resource is owned by multiple owners, each of the owners has the incentive to overcharge potential users, leading to the underuse of the resource. In R&D, different owners of complementary technologies may overcharge potential R&D firms that want to assemble different technological pieces to produce a new one. The result is forgoing research and development of new products.<p>The results of personal interviews with thirteen canola researchers and IP officers are presented and analyzed. The results suggest that the increase in the intellectual property protection in the last two decades in the canola breeding sector has led to difficulties with canola R&D. These difficulties take the form of reduced access to current, proprietary and public material. With hampered access to research input material, research output is not maximized and potential research may be forgone. Interviewees described how the increase in the intellectual property protection affects their personal and organizations ability to conduct research as well as some the implications of the new IP regime on the canola breeding sector. There is indication that canola breeding sector is moving towards a super-protectionism. Under these conditions, canola R&D firms, private and public, are in search for ways that will open access to enabling technologies and research areas. The creation of platform technologies and collaborations are the most prominent ones and are observed to increase in occurrence world wide.