京都大学 / 新制・論文博士 / 博士(医学) / 乙第13552号 / 論医博第2281号 / 新制||医||1067(附属図書館) / (主査)教授 武藤 学, 教授 小濱 和貴, 教授 佐藤 俊哉 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM

This dissertation develops new approaches for hyperspectral image visualization. Double and multiple layers are proposed to effectively convey the abundant information contained in the original high-dimensional data for practical decision-making support. The contributions of this dissertation are as follows. 1.Development of new visualization algorithms for hyperspectral imagery. Double-layer technique can display mixed pixel composition and global material distribution simultaneously. The pie-chart layer, taking advantage of the properties of non-negativity and sum-to-one abundances from linear mixture analysis of hyperspectral pixels, can be fully integrated with the background layer. Such a synergy enhances the presentation at both macro and micro scales. 2.Design of an effective visual exploration tool. The developed visualization techniques are implemented in a visualization system, which can automatically preprocess and visualize hyperspectral imagery. The interactive tool with a userriendly interface will enable viewers to display an image with any desired level of details. 3.Design of effective user studies to validate and improve visualization methods. The double-layer technique is evaluated by well designed user studies. The traditional approaches, including gray-scale side-by-side classification maps, color hard classification maps, and color soft classification maps, are compared with the proposed double-layer technique. The results of the user studies indicate that the double-layer algorithm provides the best performance in displaying mixed pixel composition in several aspects and that it has the competitive capability of displaying the global material distribution. Based on these results, a multi-layer algorithm is proposed to improve global information display.

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京都大学 / 新制・課程博士 / 博士(工学) / 甲第23913号 / 工博第5000号 / 新制||工||1780(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 作花 哲夫, 教授 安部 武志, 教授 阿部 竜 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

Due to the widespread demands for efficient Propositional Satisfiability (SAT) solvers and its derivatives in Electronic Design Automation applications, methods to boost the performance of the SAT solver are highly desired. This dissertation aims to enhance the performance of SAT and related SAT solving problems. A hybrid solution to boost SAT solver performance is proposed as an initial attack in this dissertation, via an integration of local and DPLL-based search approaches. Next, a different hybrid strategy is attempted that takes advantage of the conflicts in the SAT search, which plays a critical role in modern SAT solvers. Usually a learned conflict-induced clause is added back to the clause database. Although conflict-induced clauses help to block a portion of the search space, they can also become a burden due to the added cost in memory consumption and Boolean Constraint Propagation (BCP). We thus propose a novel double-layer conflict-driven learning to store only those "primary" conflict clauses back into the clause database while keeping the other clauses as pseudo Boolean constraints. With this approach our experiments demonstrate that the approach can improve both in performance and memory consumption. This work opens the door on how to assess the usefulness of conflict induced clauses. Besides the aforementioned works about enhancing SAT solver performance and reducing memory cost, this dissertation also proposed a contributing work on the extended SAT problem solving. The current SAT solvers can provide an assignment for a satisfiable propositional formula. However, the capability for a SAT solver to return an "optimal" solution for a given objective function is severely lacking. MIN-ONE SAT is an optimization problem which requires the satisfying assignment with the minimal number of Ones, and it can be easily extended to minimize an arbitrary linear objective function. While some research has been conducted on MIN-ONE SAT, the existing algorithms do not scale very well on large formulas. This dissertation presents a novel approximation algorithm (RelaxSAT) for MIN-ONE SAT. RelaxSAT generates a set of constraints from the objective function to guide the search. The constraints are gradually relaxed to eliminate the conflicts with the original Boolean SAT formula until a solution is found. The experiments demonstrate that RelaxSAT is able to handle very large instances which cannot be solved by existing MIN-ONE algorithms; furthermore, RelaxSAT is able to obtain a very tight bound on the solution with one to two orders of magnitude speedup. Based on the proposed powerful MIN-ONE SAT algorithm, we built a MAX-SAT solver which achieved more than one order of magnitude speed up compared with the-state-of-art MAX-SAT solver. We also discuss a promising application of this MAX-SAT solver in formal verification. / Ph. D.

Carbon nanotubes (CNTs) have become a popular area of materials science research due to their outstanding material properties coupled with their small size. CNTs are expected to be included in a wide variety of applications and devices in the near future. Among these devices which are nearing mass production are electrochemical double layer (ECDL) supercapacitors. The current methods to produce CNTs are numerous, with each synthesis variable resulting in changes in the physical properties of the CNT. A wide array of studies have focused on the effects of specific synthesis conditions. This research expands on earlier work done using bulk nickel catalyst, alumina supported iron catalyst, and standard chemical vapor deposition (CVD) synthesis methods. This work also investigates the effect of an applied voltage to the CVD chamber during synthesis on the physical nature of the CNTs produced. In addition, the work analyzes a novel nickel catalyst system, and the CNTs produced using this catalyst. The results of the effects of synthesis conditions on resultant CNTs are included. Additionally, CNT based ECDL supercapacitors were manufactured and tested. Scanning electron microscope (SEM) analysis reveals that catalyst choice, catalyst thickness, synthesis temperature, and applied voltage have different results on CNT dimensions. Nanotube diameter distribution and average diameter data demonstrate the effect of each synthesis condition. Additionally, the concept of an alignment parameter is introduced in order to quantify the effect of an electric field on CNT alignment. CNT based ECDL supercapacitors testing reveals that CNTs work well as an active material when a higher purity is achieved. The molarity of the electrolyte also has an effect on the performance of CNT based ECDL supercapacitors. On the basis of this research, we conclude that CNT physical dimensions can be moderately controlled based on the choice of synthesis conditions. Also, the novel nickel catalyst system investigated in this research has potential to produce bulk quantities of CNT under specific conditions. Finally, purified CNTs are recommended as a suitable active material for ECDL supercapacitors.

The first part of this thesis deals with the study of mesoscopic fluctuations of the Coulomb drag resistance in double-layer GaAs/AlGaAs heterostructures, both in weak magnetic fields and strong magnetic fields. In the second part, measurements are made in a monolayer graphene structure, specifically of the quantum lifetime, and the mesoscopic resistance fluctuations at quantising magnetic fields.

O presente trabalho aborda alguns aspectos estruturais e construtivos das estruturas metálicas espaciais. Inicialmente apresentam-se um breve histórico deste sistema estrutural, algumas informações gerais a respeito das classificações das estruturas espaciais, das \'tipologias\' para alguns dos sistemas mais utilizados, assim como exemplos de aplicação destas estruturas. A seguir discutem-se aspectos relativos à análise estrutural, com a apresentação de um breve roteiro de cálculo para uma cobertura em treliça espacial. Finalmente apresentam-se alguns resultados teóricos e experimentais relativos a barras comprimidas de inércia variável ao longo do comprimento. / In this work, some structural and constructional aspects of metal space structures are presented. lnitially, a brief review of this structural system is described together with some general informations about classifications, types and applications of usual systems. In addition, some aspects about structural analysis are discussed, presenting a brief guide for a space truss design. Finally, some theoretical and experimental results are illustrated for a case of axial compression members with variable stiffness.

Biosensors are used for the detection of a range of analytes for applications in healthcare, food production, environmental monitoring and biodefence. However, many biosensing platforms are large, expensive, require skilled operators or necessitate the analyte to be labelled. Direct electrochemical detection methods present a particularly attractive platform due to the simplified instrumentation when compared to other techniques such as fluorescence-based biosensors. With modern integrated circuit capabilities electrochemical biosensors offer greater suitability for monolithic integration with any necessary signal processing circuitry. This thesis explores micro- and nanogap devices for both redox cycling and dielectric spectroscopy sensing mechanisms. By using two electrodes with interelectrode separation down to distances in the micro- and nanometre scale, several benefits can be realised. Firstly the close proximity of the two electrodes significantly reduces the interdiffusion time. This allows an electroactive species to be rapidly shuttled across the gap and switched between reduced and oxidised states. The result is feedback amplification of the amperometric response, increasing the signal. The second benefit is that the screening effect caused by electric double layers at the electrode–electrolyte interface is reduced due to the electric double layers occupying a larger fraction of the sensing volume. This significantly improves the sensor suitability for dielectric spectroscopy by increasing the potential drop across the biolayer. These two sensing mechanisms are demonstrated using a large area dual-plate microgap device for the detection of two different analytes. Utilising the first mode, detection of cysteine–cystine, an important redox couple involved in the signalling mechanism for the regulation of protein function, interaction and localisation is shown. The microgap device is then used for dielectric spectroscopy sensing of a mannose-specific uropathogenic Escherichia coli strain whilst also demonstrating the effect of ionic concentration on the capacitive response. The response of these devices is highly dependent on the interelectrode separation as well as the surface area of the electrodes. However, fabrication of large-area nanogap devices presents a significant challenge. This meant that careful optimisation and the development of novel techniques was necessary. This work reports the design, fabrication and characterisation of both a vertical and a horizontal coplanar large area nanogap device. The vertical nanogap device is fabricated using an inductively-coupled plasma reactive ion etching process to create a channel in a silicon substrate. A lower electrode is then optically patterned in the channel before anodically bonding a second identical electrode patterned on glass directly above. The horizontal nanogap device uses a different approach, utilising a state-of-the-art electron-beam lithography system to create a long serpentine nanogap with passivation to reduce fringing effects. The design allows the electron-beam lithography step to be substituted with nanoimprint lithography to reduce cost and improve throughput. Both of these devices have integrated microfluidic channels and provide a capacity for relatively high-throughput production.