京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第22757号 / 工博第4756号 / 新制||工||1744(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 五十嵐 晃, 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

In room acoustics, the directional information of sound arrivals at a listening location can be used to diagnose the origins of problematic reflections so offending surfaces or other features can be properly treated. It can also be used for other purposes, including the study of psychoacoustic indicators. Many methods have been developed in the past to derive directional information, but despite their benefits, each has had significant drawbacks that have necessitated further research into their properties and development of an improved method. This thesis presents a review of past methods, their benefits and shortcomings. It discusses many theoretical and practical issues pertaining to the Polar ETC method and methods using the cross-correlation function. It also presents a new short-time correlation-based method (STCM) for gathering directional information of sound arrivals in rooms. Computer programs were developed for the implementation of the theory. Numerical simulations and experimental measurements are shown and the results are compared to those obtained by the Polar Energy Time Curve (ETC) method. The STCM is shown to be an improvement over past methods in terms of its ability to distinguish between simultaneous arrivals, its accuracy, its computational efficiency and its equipment requirements. Limitations of the method are also discussed.

Despite over 60 years of study, the molecular pathways and mechanisms governing limb outgrowth and patterning remain poorly understood. Fgfs expressed in the AER are known to be necessary and sufficient for proximodistal limb outgrowth and have been proposed to have a chemoattractive role. Wnt5a is a secreted factor which is expressed in a gradient in the distal limb with the highest concentration next to the AER. The presence of the AER is necessary to establish this gradient. Expression of Wnt5a in a concentration dependant manner can be induced in the limb through the implantation of a bead soaked in recombinant Fgf4 protein. This indicates that Fgfs from the AER may establish the gradient of Wnt5a in the limb mesenchyme. Wnt5a-/- mutants exhibit severe shortening of the face, limbs, and body axis, with limbs being progressively truncated proximally to distally. In normal limb proximodistal outgrowth, cells are seen to grow directionally toward the AER. Previous studies done in the Barrow lab, as well as those done by myself, have shown that if a portion of the AER is removed and the cells proximal to this area are labeled, those which are close enough to intact AER will redirect their growth toward this intact AER. When Wnt5a secreting cells are implanted in the limb mesenchyme of the chick this ectopic source of Wnt5a is sufficient to redirect the growth of the mesenchyme cells toward the Wnt5a source. This indicates that the AER may mediate directed growth of limb mesenchyme cells through the establishment of the Wnt5a gradient which provides positional information to the cells. This Wnt5a gradient results in the recruitment of the mesenchyme cells toward the AER. The Ror2 receptor has been found to be involved in several different pathways involving Wnt5a which are involved in changes in polarity and migration. This makes Ror2 a likely candidate for causing changes in cell polarity and migration during distal outgrowth in the limb. To test whether Ror2 is necessary for the polarizing response of limb mesenchyme cells to the Wnt5a gradient in vivo I co-transfected a dominant-negative Ror2 (Ror2ΔC) and a GFP expression vector in the embryonic chick limb using sonoporation. Limb mesenchyme cells transfected with dominant-negative Ror2 grew as radial clones in contrast to the directional outgrowth of the control limb mesenchyme cells along the proximodistal axis. This indicates that cells expressing the dominant-negative Ror2 could no longer respond to the Wnt5a gradient in the limb mesenchyme. This supports a role for Ror2 as a receptor or co-receptor for Wnt5a in mediating directional growth and movement during proximodistal outgrowth and patterning in the limb.

Bidirectional power switching devices are needed in many power management applications, particularly in lithium-ion battery protection circuitry. A monolithic bidirectional power switch fabricated with a simplified CMOS technology is introduced in this dissertation. Throughout the design process, ISE TCAD tool plays an important role. Design variables are carefully analyzed to improve the device performance or yield the best trade off. Optimization is done with the help of TCAD simulation and theoretical calculations. The device has been successfully fabricated using simplified 0.5 micron CMOS process. The experimental result shows a breakdown voltage of 25V. Due to the interdigitated source to source design, the inter-terminal current flowing path is effectively reduced to a few microns. The experimental result shows an ultra low specific on resistance. In comparison with other bi-directional power semiconductor switches by some major semiconductor manufacturers, the proposed BDS device has less than one half of the specific on resistance, thus substantially lower on state power loss of the switch. The proposed BDS device has a unique NPNPN structure, in comparison with NPNP structure, which is the analytical structure for CMOS latch-up, the proposed device inherently exhibits a better latch up immunity than CMOS inverter, thanks to the negative feed back mechanism of the extra NPN parasitic BJT transistor. In order to implement the device into simulators like PSPICE or Cadence IC Design, a compact model named variable resistance model has been built. This simple analytical model fits quite well with experimental data, and can be easily implemented by Verilog-A or other hardware description languages. Also, macro modeling is possible provided that the model parameters can be extracted from experimental curves. Several advanced types of BDS devices have been proposed, they exceed the basic BDS design in terms of breakdown voltage and /or on resistance. These advanced structures may be prominent for further improvement of the basic BDS device to a higher extend. Some cell phone providers such as Nokia is already asking for higher breakdown voltage of BDS device, due to the possibility of incidentally insert the battery pack into the cell phone with wrong pin polarity. Hopefully, the basic BDS design or one of these advanced types may eventually be implemented into the leading brand cell phone battery packs.

The DC House project strongly relies on renewable energy sources to provide power to the house for various loads. However, when these sources are unable to provide power at a certain time, a back-up energy source from a battery must be readily available to fulfill the house’s power needs. This thesis proposes a bi-directional flyback power converter to allow a single-stage power path to charge the battery from and to discharge the battery to the DC House 48 V system bus. The design, simulation, and hardware prototype of the proposed flyback bi-directional converter will be conducted to demonstrate its feasibility. Results from a 35W prototype demonstrate the operation of the proposed converter for both charging and discharging purposes.

Volume 1 = Thesis, Volume 2 = Appendices / Asymmetry is a useful tool for osteological analysis as it detects disruptions in the developmental stability of osseous structures attributed to environmental and biomechanical environments. The primary aim of this study is to establish a baseline for normal levels of asymmetry in English archaeological populations in order to distinguish between normal population variation and increased developmental instability or biomechanical stress. Directional and fluctuating asymmetry is assessed through a database of a comprehensive selection of osteological measurements throughout the skeletons of 1753 adults and subadults. The sample is from 11 archaeological sites spanning the Anglo-Saxon to the Victorian periods. The extent of developmental instability is also determined, for the first time, by employing the prevalence of population outliers. The normal range for directional asymmetry was found to be -5.79 to 6.62%, while fluctuating asymmetry was found to be 0 to 6.53%. The extent of asymmetry, however, was found to be trait specific. Deviations from normal population levels of asymmetry were found to be due to a complex mixture of biomechanical and environmental stresses influenced by age, sex, settlement type, socio-economic status, and period-specific origins of the sample populations. Possible causes of asymmetry could be discerned from comparisons of the levels of population asymmetry when placed in the context of physical activity, social networking, health, and environment developed from the historical, archaeological and osteological record. / Andy Jagger Fund and the Francis Raymond Hudson Memorial Fund

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