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

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.

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京都大学 / 新制・課程博士 / 博士(工学) / 甲第24897号 / 工博第5177号 / 新制||工||1988(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, 教授 後藤 浩之 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

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No / Many datasets are available in the form of conventional databases, or simplified comma separated values. The machines do not adequately handle these types of unstructured data. There are compatibility issues as well, which are not addressed well to manage the transformation. The literature describes several rigid techniques that do the transformation from unstructured or conventional data sources to Resource Description Framework (RDF) with data loss and limited customization. These techniques do not present any remote way that helps to avoid compatibility issues among these data forms simultaneous utilization. In this article, a new approach has been introduced that allows data mapping. This mapping can be used to understand their differences at the level of data representations. The mapping is done using Extensible Markup Language (XML) based data structures as intermediate data presenter. This approach also allows bi-directional data transformation from conventional data format and RDF without data loss and with improved remote availability of data. This is a solution to the issue concerning update when dealing with any change in the remote environment for the data. Thus, traditional systems can easily be transformed into Semantic Web-based system. The same is true when transforming data back to conventional data format, i.e. Database (DB). This bidirectional transformation results in no data loss, which creates compatibility between both traditional and semantic form of data. It will allow applying inference and reasoning on conventional systems. The census un-employment dataset is used which is being collected from US different states. Remote bi-directional transformation is mapped on the dataset and developed linkage using relationships between data elements. This approach will help to handle both types of data formats to co-exist at the same time, which will create opportunities for data compatibility, statistical powers and inference on linked data found in remote areas.

This dissertation presents three different aspects of the incorporation of directionality into the Monte Carlo ray-trace (MCRT) environment: (1) the development of a methodology for using directional surface optical data, (2) the measurement of the bi-directional reflectivity functions for two different surfaces, and (3) MCRT simulations performed using these directional data sets. The methodology presented is based upon a rigorous analytical formulation and is capable of performing simulations of radiation exchange involving directional emission, absorption and reflection given the bi-directional reflectivity functions (BDRF) of the participating surfaces. A wavelet compression technique is presented for the management of extremely large directional data sets. The BDRFs of two different surfaces were acquired using a Surface Optics Corporation model SOC-250 bi-directional reflectometer. These data were processed according to the methodology presented and an MCRT code was used to simulate the action of the SOC-250 in measuring radiant energy reflected from the surfaces of the two samples when illuminated by the source of the SOC-250. Another MCRT code was used to simulate the radiant energy reflected into a plane at the exit of an open-ended rectangular box when the entrance to the box is illuminated by source of the SOC-250. The RMS error between the MCRT simulations of sampling using the SOC-250 and the measured data were determined and then divided by the mean BDRF level of the measured data (RMS/mean[rho]) to provide an estimate of convergence. The RMS/mean[rho] was observed to fall from as much as 138 to 0.84 for the aluminum substrate coated with Krylon Shortcuts Hunter Green Satin aerosol paint as the number of energy bundles emitted in the MCRT simulation went from 103 to 106 at an incident zenith angle of 40 deg. The RMS/mean[rho] was observed to fall from as much as 2.2 to 0.2 for the Norton (150 Fine grit) all-purpose sandpaper coated with Krylon Shortcuts Hunter Green Satin aerosol paint as the number of energy bundles emitted in the MCRT simulation went from 103 to 106 at an incident zenith angle of 40 deg. / Ph. D.