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京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第22755号 / 工博第4754号 / 新制||工||1743(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 清野 純史, 教授 高橋 良和, 准教授 古川 愛子 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Railway transportation is showing a substantial increase. Investments in new infrastructure, new fast and comfortable vehicles, and high frequency of service are important factors behind the increase. Infrastructure configuration and timetable construction play important roles in the competitiveness of railway transportation. This is especially true on single-track lines where the travel times and other timetable related parameters are severely restricted by crossings (train meetings). The crossings also make the lines’ operation more sensitive to disturbances. Since the major part of the Swedish railway network is single-track it is of great interest to examine the relationships between operation properties, such as travel times and reliability, and infrastructure configuration on single-track lines. The crossings are the core feature of single-track operation and this thesis focuses on the crossing time, i.e. the time loss that occurs in crossing situations. A simplified analytical model, SAMFOST, has been developed to calculate the crossing time as a function of infrastructure configuration, vehicle properties, timetable and delays for two crossing trains. The effect of possible surrounding trains is not taken into account and all kinds of congestion effects are thus excluded from evaluation. SAMFOST has been successfully validated against the simulation tool RailSys, which shows that this type of simplified model is accurate in non-congested situations. A great advantage of disregarding congested situations is that analysis is independent of timetable assumptions. The model also explicitly shows the effect of punctuality, which is of particular importance on single-track lines where the interdependencies between trains are strengthened by the crossings. For the same reason, the timetable is severely constrained. Nonetheless, there is often a need for changes of the timetable (crossing pattern). The thesis proposes three simple measures of timetable flexibility, all based on assigned crossing time requirements. Together, these measures can be used to evaluate how infrastructure configuration, vehicle properties, punctuality etc affect possibilities to alter the timetable. As an example of its application, SAMFOST has been used to evaluate the effect of shorter inter-station distance, partial double-track and combined crossing and passenger stop. These measures affect the operational properties quite differently. More crossing stations result in a minor decrease in travel time (lower mean crossing time) but significantly higher reliability (lower crossing time variance). These effects are independent of punctuality, which is a valuable property. A partial double-track results in shorter travel times and in some cases also higher reliability. Both effects are strongly dependent on punctuality and high punctuality is needed to achieve high effects. A combined crossing and passenger stop results in a situation similar to that of a partial double-track. In this case it is important to point out that the assignment of time supplements in the timetable should be directly correlated to punctuality in order to achieve good operation. / <p>QC 20170222</p>

Mixing in Stokes flows is notoriously difficult to achieve. With characteristic scales of the flows being too small for the turbulence to be present, and too large for the molecular diffusion to be significant, the chaotic advection presents almost the only mechanism that can lead to mixing. Unfortunately for mixing, the intrinsic symmetries of the flow create invariant surfaces that act as barriers to mixing. Thus, a key to efficient mixing is to add to the original (symmetric) flow a certain kind of perturbation that destroys those symmetries. In this dissertation, two ways of obtaining mixing in 3D near-integrable bounded time -dependent Stoke Flows are studied: resonances and separatrix crossings. First, I illustrate that the resonances between different components of the original flow and the perturbation may break the invariant surfaces, paving a way to the large-scale mixing. Theoretical estimations are compared against the results of numerical simulations, as well as 3D particle tracking velocimetry (3D-PTV) experimental results. Second, chaotic advection and mixing due to quasi-random jumps of the adiabatic invariant (AI) occurring when a streamline crosses the separatrix surfaces is studied. Analytical expressions for the change in the AI near the separatrix surfaces are derived and compared with numerical simulations. / Mechanical Engineering

Plant gene families organized as linked clusters are capable of evolving by a process of unequal crossing-over. This results in the formation of chimeric genes that may impart a novel function. However, the frequency and functional consequences of these unequal cross-over events are poorly characterized. Plant disease resistance genes (R genes) genes are frequently organized as gene clusters. In this study, I constructed an elaborately designed reconfigurable synthetic RPP1 (for resistance to Paranospora parasitica) gene cluster (synthRPP1) to model R gene evolution by meiotic recombination. This experimental design utilizes gain-of-luciferase phenotype (luc+) to identify and isolate recombinant R genes and uses two alternatively marked alleles to distinguish and measure different types of meiotic recombination (intra- vs. inter-chromosomal). Two putative single copy transgenic plants containing the synthRPP1 gene cluster were generated. These synthRPP1 gene clusters were reconfigured in vivo by two kinds of site-specific recombination systems (CRE/Lox, FLP/FRT) to generate two alternative versions of the synthRPP1 gene clusters in vivo. These lines, as well as others being developed, will be used in future genetic crosses to identify and characterize plants expressing chimeric RPP1 genes. My second area of research was to use a previously developed synthetic RBCSB gene cluster (synthRBCSB) gene cluster to investigate the relative frequency of meiotic unequal crossing over between paralogous genes located on either homologous chromosomes (homozygous lines) or sister chromatids (hemizygous lines). In contrast to published somatic recombination frequencies using a different reporter gene system, no statistically significant difference of meiotic unequal crossing over was observed between homo- and hemi-zygous synthRBCSB lines. This result suggests that meiotic unequal crossing-over between paralogs located on homologous chromosomes occurs at about the same frequency as paralogs located on sister chromatids. To investigate the rate of somatic recombination in synthRBCSB lines, a QRT-PCR method was developed to estimate the frequency of somatic recombination. Preliminary results suggest that the somatic recombination frequency was about 10,000 fold higher than meiotic recombination in the same generation. Moreover, two of five cloned chimeric genes that formed by somatic recombination indicated a different distribution of resolution sites than those observed in meiotic recombination. This finding suggests there are significant differences in both the frequency and character of somatic versus meiotic unequal crossing-over between paralogous genes in Arabidopsis. / Ph. D.

For the last century, automobiles and the roads they require have been a dominant force shaping the modern American landscape. An unrivaled interstate highway system connects major metropolitan areas and is the basis of our transportation infrastructure. Unfortunately, many roadways were not planned or designed with wildlife in mind. As long linear features in the landscape, interstates can function as landscape barriers and cause significant impacts to adjacent wildlife populations. While an aggressive transportation system is being carried out, researchers have only marginally demonstrated the relationships between roadways and wildlife. In such cases, twinned interstate roadways have proven to be the greatest obstacle for wildlife resources. By incorporating ecological design theory into highway planning and design, the transportation community has an opportunity to reassess the short comings of existing highway infrastructure and improve functions of wildlife passage and landscape connectivity. Through system level approaches and analysis applied within an eco-region context, practical solutions can be developed. The following document provides a process for landscape level analysis, wildlife passage structure design and implementation for future planned interstates projects. As a collaborative effort among professionals, we can work towards improving interstate highway systems and retain the relationships occurring within the landscape. The following I-81 design and planning project offers an exceptional opportunity to reassess the inadequacies of the existing interstate infrastructure in terms of landscape connectivity, wildlife resources and public safety, and demonstrate how system level design approaches can give our roadways new shape and form. / Master of Landscape Architecture

The performance of a mobile satellite communications link can be determined by the propagation path between a satellite and mobile users. Some of the most important factors are multipath propagation and vegetative shadowing. System designers should have the most reliable information about the statistics of fade duration in order to determine fade margin or to compensate for the fades using modulation and coding scheme. This report describes a simulator, PROSIM, developed at Virginia Tech for simulating a propagation model in land mobile satellite communications. The simulator is based on a random number generator that generates data sets to compute statistics of the propagation channel. Performance of the simulator was evaluated by comparing statistics from an analytical model and experimental data provided by W. Vogel of Univ. of Texas at Austin and J. Goldhirsh of the Applied Physics Laboratory. New expressions for phasor plot and its mathematical expression for lognormal channel were derived and were simulated. Finally, the advantages of the simulator using random number generator in simulating the propagation model are described. / Master of Science

Videogames are, without doubt, disappearing and the continued – and accelerating – loss of this material denies future generations access to their cultural heritage and robs the next generation of developers historical reference material to draw on. As Henry Lowood [2009] pointed out more than a decade ago, we need to take action “before it’s too late”. The video-paper offers an overview and critique of existing approaches and revisits some of the methodological and conceptual presuppositions that underpin game preservation and even the academic discipline of game studies as a whole. Returning to first principles, the paper asks “What Do Videogames Want?”.