京都大学 / 新制・課程博士 / 博士(理学) / 甲第22978号 / 理博第4655号 / 新制||理||1669(附属図書館) / 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 照井 一成, 教授 長谷川 真人, 准教授 河村 彰星 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

A growing proportion of young adults report regularly playing video games and using electronic nicotine delivery systems (ENDS). Although video gaming is often normative and adaptive, excessive gaming is associated with adverse health outcomes and dependency, as seen in gaming disorder/internet gaming disorder (GD/IGD). Possible additive detrimental effects of ENDS use on the physical outcomes of GD/IGD lend particular concern to these concurrent behaviors. The present study explored group differences in concurrent ENDS and GD/IGD dependency by demographic factors, including age, sex, gender, sexual orientation, racial identity, relationship status, and year in school. The interaction effect of symptoms of attention-deficit hyperactivity disorder (ADHD) on the association between ENDS dependency and GD/IGD was also examined. Lastly, group differences in ADHD symptoms for individuals who endorse (1) neither GD/IGD nor ENDS dependency, (2) either GD/IGD or ENDS dependency, or (3) both GD/IGD and ENDS dependency were explored. Data were collected in a large, multi-university sample of college students (N = 1,054). Higher symptoms of GD/IGD were positively associated with greater symptoms of ENDS dependency. Men and individuals with significant symptoms of ADHD were at an increased risk of concurrent GD/IGD and ENDS dependency. These results may be used to identify demographic and psychological associations linked to these comorbidities, ultimately informing future prevention strategies.

Cascaded H-bridge (CHB) multilevel inverters have significant popularity with motor drives applications due to their modularity, scalability, and reliability. Typical CHB inverters employ diode rectifiers that allow unidirectional power flow from the grid to the load. To capture and utilize the regenerated energy in regenerative applications, regenerative CHB drives were introduced with two-level voltage source converters in the front end to allow bidirectional energy flow. This solution is accompanied by challenges of high number of switches and control circuits, high switching power losses, and massive dimensions. Recently, developing more economic versions of regenerative cascaded H-bridge drives has become one of the hottest topics in power electronics research. In this thesis work, two solutions are proposed for more energy efficient and economic regenerative CHB drives. The first solution is a proposed power cell configuration that reduces the number of switches per cell by two. Additionally, phase alternation connection method and carrier phase-shifting techniques are introduced to address the challenges of the presented configuration. The switch-count reduction reduces the system’s complexity, switches’ cost, and footprint. The second proposed solution is a new controller to operate the front-end converters as fundamental frequency ends (FFEs). The proposed controller is employed in both the conventional regenerative cascaded H-bridge and the proposed reduced switch-count configuration. This solution minimizes the switching power losses, and results in more compact and economic design, with higher DC-link utilization. Theoretical analysis and simulation studies of both proposed solutions show promising performance and capability to be applied as energy-efficient and cost effective regenerative CHB motor drives. Experimental validation of the proposed reduced switch-count configuration is presented for STATCOM operation of a scaled-down 7-Level regenerative CHB drive system. The future work of this thesis includes experimental validation of the proposed FFE controller, and operation of the system with regenerative motor load. / Thesis / Master of Applied Science (MASc)

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The Puritans constituted a very vocal influential minority during the time of Shakespeare. One of their more interesting ideas was the doctrine of the covenant, which explained why a transcendent God would care for fallen human beings. God, for Puritans, voluntarily bound himself in a covenant to man. The interrelations of elements of grace and works make it difficult to interpret what a covenant should be like: more like a modern contract or more like a feudalistic promise system? Unlike a contract, God never ends the covenant even when humans disregard their commitment, but instead helps humans fulfill their obligations by means of mercy. The covenant also sets out specific limitations that each party is required to fulfill like a contract. Puritans applied this pattern of the covenant not only to their relationship with God, but to other relationships like business, government, and most interestingly marriage. I will focus on how Shakespeare sets out this same covenantal pattern between man and God in his depiction in Portia's and in Helena's marriages respectively. I use sixteenth and seventeenth century Puritan treatises and sermons as well as secondary experts to illustrate Shakespeare's invocation of a Puritan marriage. This Puritan interpretation of the marriage covenant points toward equality by making the couple equally obligated in the contract, yet requiring more than mere obligation. These authors believed that the marriage covenant should not just be for procreation, but cohabitation and communion of the mind.

Over the past few years, speech recognition technology performance on tasks ranging from isolated digit recognition to conversational speech has dramatically improved. Performance on limited recognition tasks in noiseree environments is comparable to that achieved by human transcribers. This advancement in automatic speech recognition technology along with an increase in the compute power of mobile devices, standardization of communication protocols, and the explosion in the popularity of the mobile devices, has created an interest in flexible voice interfaces for mobile devices. However, speech recognition performance degrades dramatically in mobile environments which are inherently noisy. In the recent past, a great amount of effort has been spent on the development of front ends based on advanced noise robust approaches. The primary objective of this thesis was to analyze the performance of two advanced front ends, referred to as the QIO and MFA front ends, on a speech recognition task based on the Wall Street Journal database. Though the advanced front ends are shown to achieve a significant improvement over an industry-standard baseline front end, this improvement is not operationally significant. Further, we show that the results of this evaluation were not significantly impacted by suboptimal recognition system parameter settings. Without any front end-specific tuning, the MFA front end outperforms the QIO front end by 9.6% relative. With tuning, the relative performance gap increases to 15.8%. Finally, we also show that mismatched microphone and additive noise evaluation conditions resulted in a significant degradation in performance for both front ends.

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No description available.

Le gène split end (spen) est impliqué dans de nombreuses voies de signalisation et processus biologiques. Durant ma thèse j'ai étudié le rôle de spen dans la mort cellulaire au cours du développement de la rétine de la Drosophile. L'œil de Drosophile est composé de centaines d'unités appelées ommatidies. Chaque ommatidie est composée de huit photorécepteurs entourés de cellules accessoires comprenant quatre cellules cônes et deux cellules pigmentaires primaires, ainsi que douze cellules interommatidiales. Les cellules interommatidiales adoptent une structure hexagonale parfaitement régulière. Des cellules interommatidiales en excès doivent être éliminées par apoptose au cours du développement. J'ai montré que la modulation de spen modifiait radicalement le patron des cellules interommatidiales. L'inactivation de spen conduit à un défaut de cellules interommatidiales alors que sa surexpression entraîne un excès de ces cellules. Ces résultats témoignent d’un rôle anti-apoptotique de spen. Nous avons aussi montré que la perte des cellules interommatidiales dans un contexte mutant pour spen pouvait être entièrement sauvée en exprimant la protéine p35 connue pour bloquer l'activité des caspases. Comme spen est exprimé de manière ubiquitaire, nous avons cherché à déterminer dans quelles cellules spen jouait son rôle de régulateur de la mort cellulaire. Grâce à une analyse clonale, nous avons pu montrer que c'est au niveau des cellules cônes que spen agit. L'inactivation de spen dans les autres cellules accessoires de l'œil n'influence pas la mort des cellules interommatidiales. Nous avons en outre, montré que spen avait un rôle dans la formation des soies de chaque ommatidie. Ces travaux mettent en évidence un rôle de spen dans le contrôle de la mort cellulaire des cellules interommatidiales dans les cellules cônes. Nos résultats montrent, par ailleurs, que spen serait requis pour le relarguage du facteur de survie Spitz (le ligand activateur de la voie EGF) à partir des cellules cônes. En parallèle, nous avons étudiés le rôle de survie de spen dans un modèle neurodégénératif. Nous avons montré que spen était nécessaire dans les cellules gliales pour la résistance au stress oxydatif. De manière intéressante, nous avons trouvé que l'inactivation de spen dans la glie diminuait l'activité de la voie de signalisation NOTCH. Cette résistance pourrait se faire via la modulation de gènes antioxydants. De manière générale, nos travaux démontrent un rôle du gène split ends dans la survie cellulaire. Ce facteur agit de manière non-autonome à partir des cellules supports de différents organes. / In metazoan, the successful development of many organs requires the elimination of supernumerary cells by apoptosis. For example, the elimination of about two thousand interommatidial cells (IOCs) during Drosophila eye development allows the precise rearrangement of ommatidia in a perfect hexagonal array. Maximal apoptosis occurs during pupal life and the remaining IOCs differentiate into secondary and tertiary pigment cells. The precise removal of unwanted IOCs requires coordinated activation of Notch (pro-death) and EGF (pro-survival) pathways. IOCs undergoing apoptosis express the IAP inhibitor Hid, which leads to the activation of initiator and effector caspases. However, the mechanisms that coordinate the death and survival pathways for timed and precise IOC removal are poorly understood.Here, we report that spen encodes a nuclear protein expressed in the pupal eye that is required for IOC survival. We showed that the inhibition of spen, by either RNAi or in spen mutant clones resulted in disorganized ommatidia with missing IOCs. Moreover, overexpression of spen leads to extra IOCs. These results indicate that spen expression promotes IOC survival during eye development. Importantly blocking apoptosis prevents the loss of IOC in a spen mutant retina. Spen is a protein known to be ubiquitous in tissue during development. Indeed, we have shown using an enhancer trap line that spen is expressed in all the cells in the eye pupal disk. To better understand where spen is acting from in this tissue to regulate cell death, we performed a clonal analysis. We found that the inactivation of spen in the cone cells was causing the loss of IOC, indicating that spen is required non-autonomously in cone cell for IOC survival. In parallel we have shown that the inactivation of spen was disrupting eye bristles morphology. Even if studies discuss the role of bristles in the regulation of developmental apoptosis in this context, our clonal analysis excluded this possibility. Furthermore, we found that spitz, the EGFR ligand, accumulate in cone cells upon spen inactivation. Our current hypothesis is that spen is likely to be required for the release of Spitz from the cone cells in order to active the survival signaling pathway EGFR in the IOCs. Also, we examined the protective role of spen in a chemical model of Parkinson disease (paraquat treatment). We showed that the glial expression of spen is protective in this context, which suggest against that spen acts non-autonomously. Interestingly we found that the inactivation of spen in glia downregulates the Notch signaling pathway. Spen is likely to be a key factor integrating cues from different signaling pathways to promote cell survival.

The notion of Mode 2, as a shift from Mode 1 science-as-we-know-it, depicts science as practically relevant, socially distributed and democratic. Debates remain over the empirical substantiation of Mode 2. In particular, our understanding has been impeded by the mutually exclusive framing of Mode 1/Mode 2. Looking at how academic science is justified to diverse institutional interests – a situation associated with Mode 2 – it is asked, “What happens to Mode 1 where Mode 2 is in demand?” This study comprises two sequential phases. It combines interviews with 18 university spinout founders as micro-level Mode 2 exemplars, and macro-level policy narratives from 72 expert witnesses examined by select committees. An interpretive scheme (Greenwood and Hinings, 1988) is applied to capture the internal means-ends structure of each mode, where the end is to satisfy demand constituents, both in academia (Mode 1) and beyond (Mode 2). Results indicate Mode 1’s enduring influence even where non-academic demands are concerned, thus refuting that means and ends necessarily operate together as a stable mode. The causal ambiguity inherent in scientific advances necessitates (i) Mode 1 peer review as the only quality control regime systematically applicable ex ante, and (ii) Mode 1 means of knowledge production as essential for the health and diversity of the science base. Modifications to performance criteria are proposed to create a synergy between modes and justify public investment, especially in the absence of immediate outcomes. The study presents a framework of Mode1/Mode 2 coexistence that eases the problem with the either/or perception and renders Mode 2 more amenable to empirical research. It is crucial to note, though, that this is contingent on given vested interests. In this study, Mode 1’s fate is seen through academic scientists whose imperative is unique from those of other constituents, thereby potentially entailing further struggles and negotiation.