This study evaluates the impact of pedestrian flow through vehicular delays in a proposed DLT intersection located in an urban area with a high vehicular and pedestrian traffic volume. In addition, it evaluates the pedestrian–vehicle conflict points, the effect on the other accesses after the implementation of the displaced left turns, and the consequences of reorganizing pedestrian flow. Three scenarios are evaluated through microsimulation; the existing one, which is a conventional cross-shaped intersection; a proposed DLT intersection with two displaced left turns on adjacent accesses; and a third one, similar to the last one, but with the inclusion of a pedestrian underpass. Results indicate that a proposed conventional DLT increases the vehicle delays of the intersection by 6.0% compared to the existing condition, mainly due to the high volume of pedestrians and the conflicts it generates. However, with the inclusion of a pedestrian underpass, vehicle delays are reduced significantly by up to 34.0%.

The thesis Is concerned with the development of a separately excited DC machine In which gate turn-off thyristor devices with their associated firing and protective circuits are used to provide the static commutation of armature coil current. The developed machine has Its armature winding with 24 tapping points located on the stator and Interconnected In "Lop" configuration. The Initiation of the conduction periods of armature switching devices Is defined by a digital control logic circuit. In conjunction with an Incremental rotary encoder which provides the necessary feedback Information relating to shaft speed and shaft angular position. This Is arranged such that, under normal running conditions of the machine, the axis of the radial field of the armature winding maintains the normal space-quadrature relationship with that of the main field winding, giving the optimal torque angle of 000. Provision Is made, however, within the digital control circuit for controlled departure of the armature switch tapping points from the quadrature axis positions, and the effect of this, In Improving commutation Is Investigated. The effect of Interpoles Is also explored. On the basis of the analysis carried out, a proposal Is made for the future development of the machine employing a reduced number of armature switching devices without the need for Interpole windings. / Electricity Directorate, Ministry of Works, Power and Water, Manama, Bahrain.

Mobility models serve as the foundation for evaluating and designing airborne networks. Due to the significant impact of mobility models on the network performance, mobility models for airborne networks (ANs) must realistically capture the attributes of ANs. In this paper, I develop a comprehensive modeling framework for ANs. The work I have done is concluded as the following three parts. First, I perform a comprehensive and comparative analysis of AN mobility models and evaluate the models based on several metrics: 1) networking performance, 2) ability to capture the mobility attributes of ANs, 3) randomness levels and 4) associated applications. Second, I develop two 3D mobility models and realistic boundary models. The mobility models follow physical laws behind aircraft maneuvering and therefore capture the characteristics of aircraft trajectories. Third, I suggest an estimation procedure to extract parameters in one of the models that I developed from real flight test data. The good match between the estimated trajectories and real flight trajectories also validate the suitability of the model. The mobility models and the estimation procedure lead to the creation of “realistic” simulation and evaluation environment for airborne networks.

付記する学位プログラム名: 充実した健康長寿社会を築く総合医療開発リーダー育成プログラム / 京都大学 / 新制・課程博士 / 博士(工学) / 甲第23915号 / 工博第5002号 / 新制||工||1781(附属図書館) / 京都大学大学院工学研究科物質エネルギー化学専攻 / (主査)教授 大江 浩一, 教授 近藤 輝幸, 教授 浜地 格 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

The first part of this work describes the synthesis of a new histone deacetylase (HDAC) inhibitor (HDI). HDAC enzymes modify core histones, influence nucleosome structure and change gene transcription by removing the acetyl groups from lysine residues on proteins. HDIs are showing exciting potential as a new class of drugs for cancer and a variety of other diseases. A new HDAC inhibitor based on the hydroxamic acid motif has been synthesized. Two characteristic structural features were incorporated into the design of the novel inhibitor. A cyclic peptide mimetic of known structure was fused to a hydroxamic acid moiety through an aliphatic chain. The HDAC inhibitor provided significant inhibitory activity against HDACs with an IC50 value of 46 ± 15 nM, and against HDAC8 with an IC50 value of 208 ± 20 nM. The potent HDAC inhibitory activity of the HDAC inhibitor demonstrates the importance of the rim recognition region in the design of HDIs. The hydrophobic cyclic turn mimic allows the formation of a tight complex between HDI and HDAC enzymes. The second part of this work is to synthesize secondary structure mimics and incorporate them into the helix-turn-helix (HTH) motif. One of the important methods to study the conformation of the biologically active peptides is to incorporate the rigid peptidomimetics into the relevant peptides. Important information can be obtained from the study of conformationally constrained peptides. HTH proteins are well characterized and found in many organisms from prokaryotes to eukaryotes. The relatively small size, simple structure, and significance in stabilizing tertiary structures make the HTH peptide an attractive target to mimic. Both a Gly HTH turn mimic and a Ser HTH turn mimic were synthesized using stereoselective hydrogenation and macrocyclization starting from unnatural amino acids in a yield of 33% and 14%, respectively. The synthesis of Fmoc protected HTH turn mimics allowed incorporation into HTH peptides using Fmoc chemistry on solid phase. The incorporation of the HTH turn mimics into the peptides proved to be challenging, either by sequential elongation or by segment condensation. Alternative peptide synthesis strategies were employed in attempts to solve the problems. / Ph. D.

The Gate Turn-Off (GTO) Thyristor has the best voltage blocking and current conducting capabilities among all known high power semiconductor devices. To improve its dynamic performances to meet the increased demand in high-performance high-power applications, a special driving technique, namely unity gain turn-off, is studied. Several innovative approaches, which realize this driving requirement, are proposed, analyzed and experimentally demonstrated in this dissertation. The Emitter Turn-Off Thyristor (ETO) is a new family of high power semiconductor devices that is suitable for megawatt power electronics application. ETOs with voltage and current ratings of 4.0~6.0 kV and 1.0~4.0 kA, have been developed and demonstrated. These power levels are the highest in silicon power devices and are comparable to those of the GTO. Compared to the conventional GTO, the ETO has a much shorter storage time, voltage controlled turn-off capability, and a much larger reverse biased safe operation area (RBSOA). These combined advantages make the ETO based power system simpler in terms of dv/dt snubber, di/dt snubber and over current protection, resulting in significant savings at the system level. Experimental and numerical simulation results that demonstrate the advantages of the ETO are presented. A new family of snubberless turn-off GTO, the Resonant Gate Commutated Thyristor (RGCT) is proposed and investigated. By using a transient high commutation voltage, the RGCT can achieve unity turn-off gain and snubberless turn-off capability even with a relatively high gate loop stray inductance. Therefore conventional GTOs with flexible gate lead can be used to achieve the state-of-the-art performance similar to that of the Integrated Gate Commutated Turn-Off thyristor (IGCT). Detailed current commutation analysis and experimental results are presented. A novel equivalent circuit model for the GTO under the unity gain turn-off is proposed. This model is composed of a step current source, which represents the open-base PNP turn-off behavior, in series with a diode that represents the GTO's gate-cathode junction. This equivalent circuit can be used to analyze the turn-off transient behavior of a system employing this GTO. A new mechanism that dominates the failure of the GTO under the unity gain turn-off condition is identified and analyzed. Innovative hybrid GTO-based devices all have significant gate lead stray inductance. During the turn-off transition, this stray inductor will interact with the turn-off voltage source, the junction capacitance of the GTO's gate-cathode, causing effective current injection into the GTO's emitter junction when the voltage on the device is already high. Design guidelines and solutions for different types of GTO-based hybrid devices are provided. / Ph. D.

This study adds to the literature on the persisting gender gap in STEM by examining the participation trends of women and men undergraduate students in the physics classroom. Specifically, this study builds on the existing literature of proportions in group interaction originally theorized by Kanter (1977) and investigates the turn-taking behaviors of women and men in classes that differ in their relative levels of gender representation. This study posed four hypotheses: That women will average less oral participation in the physics classroom than men, that more highly skewed classes will result in greater differences in men's and women's participation, that there will be an observable tipping point in women's participation, and that women's average participation will go up with the proportion of women in the classroom. These hypotheses were tested in 10 physics classrooms over the course of one class period each. The student-initiated turns during these class periods were coded by individual turn-taker. These data were analyzed to determine differences between men and women students' turn-taking behaviors in the physics classroom in relation to the proportion of women and men in the classroom. Findings indicate that women did average less participation than men in the physics classroom. However, the data do not point to a consistent relationship between increases in proportions of women in the physics class and increases in women's participation in the class. / Master of Science / This study looked to understand the differences in women's and men's in-class volunteered participation in the college physics classroom. Specifically, this study builds on the existing literature on the effects of group gender proportion in interaction, or how the proportion of women to men in a group shapes women's interactions, originally developed by Kanter (1977) and investigates the turn-taking behaviors, or how speech in conversation is initiated, of women and men in classes that differ in their gender compositions. This study had four hypotheses: 1) That women will have less volunteered participation in the physics classroom than men 2) That more highly skewed classes, or classes with high proportions of men and low proportions of women, will result in greater differences in men's and women's participation 3) That there will be an observable tipping point, a point when an increase in women in the classroom will cause an increase in women's participation 4) That women's participation will go up with the number of women in the classroom. These hypotheses were tested in 10 physics classrooms over the course of one class period each. The voluntary, student-initiated participation during these class periods were looked at by individual student. The information gathered was analyzed to understand if there were differences between men and women students' amount of participation in the physics classroom in relation to the composition of women and men in the classroom. The study found that women did average less participation than men in the physics classroom. However, the information gathered did not point to a relationship between the increases in the proportion of women in the physics class and increases in women's participation in the class.

This thesis examines interactional dimensions of the 2008 U.S. presidential debates based on the conversation analytic concepts of sequence organization and turn management. Drawing on the video recordings of the three 2008 presidential debates, I investigate features of turn design and interactional strategies that candidates employ during the debates and compare stylistic differences between John McCain and Barack Obama. I first examine how candidates design their first-turn responses to the moderator’s question in terms of placement of two different actions, answer and attack. Secondly, I focus on design of the second-turn responses and examine how candidates show responsiveness to both the moderator’s question and the opponent’s prior turn by incorporating multiple actions (e.g., attack, defense, and answer) in their second turns. I also examine direct exchanges between McCain and Obama, particularly concerning their strategic use of the record and their interactional practices in claiming turns and managing overlapping talk in confrontation sequences. My analysis shows that some stylistic differences exist between McCain’s and Obama’s turns. I provide detailed description of how Obama makes a systematic transition from answer to attack in his first-turn responses, which is distinguished from McCain’s first turns in which attacks are inserted in his answer as relevant topics are brought up. My analysis of the second-turn responses shows that McCain frequently produces an attack at turn beginning or responds to an attack with a reciprocal attack before producing a defense, while Obama tends to produce a defense first and then move to an attack. Lastly, I discuss how both Obama and McCain manage their turns and use turn-taking techniques to avoid direct references to their own record and shift the focus of the talk to the opponent’s stance on a related issue. / text

A power transformer is one of the most important and expensive components in any power system. Power transformers can be exposed to a wide variety of abnormal conditions and faults. Internal turn-to-turn faults are the most difficult types of faults to detect within the power transformer. The IEEE Standards documents have revealed that there is no one standard way to protect all power transformers against minor internal faults such as turn-to-turn faults and at the same time to satisfy basic protection requirements: sensitivity, selectivity, and speed.<p> This thesis presents a new, simple and efficient protection technique which is based on negative sequence currents. Using this protection technique, it is possible to detect minor internal turn-to-turn faults in power transformers. Also, it can differentiate between internal and external faults. The discrimination is achieved by comparing the phase shift between two phasors of total negative sequence current. The new protection technique is being studied via an extensive simulation study using PSCAD®/EMTDC 1 software in a three-phase power system and is also being compared with a traditional differential algorithm.<p> Relay performance under different numbers of shorted turns of the power transformer, different connections of the transformer, different values of the fault resistances, and different values of the system parameters was investigated. The results indicate that the new technique can provide a fast and sensitive approach for identifying minor internal turn-to-turn faults in power transformers.

A power transformer is one of the most important and expensive components in any power system. Power transformers can be exposed to a wide variety of abnormal conditions and faults. Internal turn-to-turn faults are the most difficult types of faults to detect within the power transformer. The IEEE Standards documents have revealed that there is no one standard way to protect all power transformers against minor internal faults such as turn-to-turn faults and at the same time to satisfy basic protection requirements: sensitivity, selectivity, and speed.<p> This thesis presents a new, simple and efficient protection technique which is based on negative sequence currents. Using this protection technique, it is possible to detect minor internal turn-to-turn faults in power transformers. Also, it can differentiate between internal and external faults. The discrimination is achieved by comparing the phase shift between two phasors of total negative sequence current. The new protection technique is being studied via an extensive simulation study using PSCAD®/EMTDC 1 software in a three-phase power system and is also being compared with a traditional differential algorithm.<p> Relay performance under different numbers of shorted turns of the power transformer, different connections of the transformer, different values of the fault resistances, and different values of the system parameters was investigated. The results indicate that the new technique can provide a fast and sensitive approach for identifying minor internal turn-to-turn faults in power transformers.