Recently an effective usage of the chip area plays an essential role for System-on-Chip (SOC) designs. Nowadays on-chip memories take up more than 50%of the total die-area and are responsible for more than 40% of the total energy consumption. Cache memory alone occupies 30% of the on-chip area in the latest microprocessors. This thesis project “System Level Exploration of RRAM for SRAM Replacement” describes a Resistive Random Access Memory (RRAM) based memory organizationfor the Coarse Grained Reconfigurable Array (CGRA) processors. Thebenefit of the RRAM based memory organization, compared to the conventional Static-Random Access Memory (SRAM) based memory organization, is higher interms of energy and area requirement. Due to the ever-growing problems faced by conventional memories with Dynamic Voltage Scaling (DVS), emerging memory technologies gained more importance. RRAM is typically seen as a possible candidate to replace Non-volatilememory (NVM) as Flash approaches its scaling limits. The replacement of SRAMin the lowest layers of the memory hierarchies in embedded systems with RRAMis very attractive research topic; RRAM technology offers reduced energy and arearequirements, but it has limitations with regards to endurance and write latency. By reason of the technological limitations and restrictions to solve RRAM write related issues, it becomes beneficial to explore memory access schemes that tolerate the longer write times. Therefore, since RRAM write time cannot be reduced realistically speaking we have to derive instruction memory and data memory access schemes that tolerate the longer write times. We present an instruction memory access scheme to compromise with these problems. In addition to modified instruction memory architecture, we investigate the effect of the longer write times to the data memory. Experimental results provided show that the proposed architectural modifications can reduce read energy consumption by a significant frame without any performance penalty.

Application-specific optimization of embedded systems becomes inevitable to satisfy the market demand for designers to meet tighter constraints on cost, performance and power. On the other hand, the flexibility of a system is also important to accommodate the short time-to-market requirements for embedded systems. To compromise these incompatible demands, coarse-grained reconfigurable architecture (CGRA) has emerged as a suitable solution. A typical CGRA requires many processing elements (PEs) and a configuration cache for reconfiguration of its PE array. However, such a structure consumes significant area and power. Therefore, designing cost-effective CGRA has been a serious concern for reliability of CGRA-based embedded systems. As an effort to provide such cost-effective design, the first half of this work focuses on reducing power in the configuration cache. For power saving in the configuration cache, a low power reconfiguration technique is presented based on reusable context pipelining achieved by merging the concept of context reuse into context pipelining. In addition, we propose dynamic context compression capable of supporting only required bits of the context words set to enable and the redundant bits set to disable. Finally, we provide dynamic context management capable of reducing reduce power consumption in configuration cache by controlling a read/write operation of the redundant context words In the second part of this dissertation, we focus on designing a cost-effective PE array to reduce area and power. For area and power saving in a PE array, we devise a costeffective array fabric addresses novel rearrangement of processing elements and their interconnection designs to reduce area and power consumption. In addition, hierarchical reconfigurable computing arrays are proposed consisting of two reconfigurable computing blocks with two types of communication structure together. The two computing blocks have shared critical resources and such a sharing structure provides efficient communication interface between them with reducing overall area. Based on the proposed design approaches, a CGRA combining the multiple design schemes is shown to verify the synergy effect of the integrated approach. Experimental results show that the integrated approach reduces area by 23.07% and power by up to 72% when compared with the conventional CGRA.

Friction stir processing (FSP) is applied to produce particulate-reinforced aluminum matrix composites with ultrafine grained structure from elemental powder mixtures of Al-Cu, Al-Ti and Al-Si. The microstructures of the composites were characterized by the use of XRD, SEM and TEM. Microhardness, tensile and compressive tests were performed to evaluate the mechanical properties of these composites. The mechanisms of microstructure evolution in FSP and the strengthening mechanisms in these composites are discussed. In the Al-Si system, the Si particles were broken and uniformly distributed in the stir zone by the application of multiples-pass FSP. The average size of Si particles and Al grains were refined to below ~2

Recent ground failure case histories after 1994 Northridge, 1999 Kocaeli and 1999 Chi-Chi earthquakes revealed that low-plasticity silt-clay mixtures generate significant cyclic pore pressures and can exhibit a strain-softening response, which may cause significant damage to overlying structural systems. These observations accelerated research studies on liquefaction susceptibility of fine-grained soils. Alternative approaches to Chinese Criteria were proposed by several researchers (Seed et al. 2003, Bray and Sancio 2006, Boulanger and Idriss 2006) most of which assess liquefaction triggering potential based on cyclic test results compared on the basis of index properties of soils (such as LL, PI, LI, wc/LL). Although these new methodologies are judged to be major improvements over Chinese Criteria, still there exist unclear issues regarding if and how reliably these methods can be used for the assessment of liquefaction triggering potential of fine grained soils. In this study, results of cyclic tests performed on undisturbed specimens (ML, CL, MH and CH) were used to study cyclic shear strain and excess pore water pressure generation response of fine-grained soils. Based on comparisons with the cyclic response of saturated clean sands, a shift in pore pressure ratio (ru) vs. shear strain response is observed, which is identified to be a function of PI, LL and (wc/LL). Within the confines of this study, i) probabilistically based boundary curves identifying liquefaction triggering potential in the ru vs. shear strain domain were proposed as a function of PI, LL and (wc/LL), ii) these boundaries were then mapped on to the normalized net tip resistance (qt,1,net) vs. friction ratio (FR) domain, consistent with the work of Cetin and Ozan (2009). The proposed framework enabled both Atterberg limits and CPT based assessment of liquefaction triggering potential of fine grained low plasticity soils, differentiating clearly both cyclic mobility and liquefaction responses.

The move into deeper waters in the Gulf of Mexico has produced new opportunities for petroleum production, but it also has produced new challenges as different reservoir problems are encountered. This integrated reservoir characterization effort has provided useful information about the behavior and characteristics of a typical unconsolidated, overpressured, fine-grained, turbidite reservoir, which constitutes the majority of the reservoirs present in the Outer Continental Shelf of the Gulf of Mexico. Reservoirs in the Green Canyon 18 (GC 18) field constitute part of a turbidite package with reservoir quality typically increasing with depth. Characterization of the relatively shallow 8 reservoir had hitherto been hindered by the difficulty in resolving its complex architecture and stratigraphy. Furthermore, the combination of its unconsolidated rock matrix and abnormal pore pressure has resulted in severe production-induced compaction. The reservoir's complex geology had previously obfuscated the delineation of its hydrocarbon accumulation and determination of its different resource volumes. Geological and architectural alterations caused by post-accumulation salt tectonic activities had previously undermined the determination of the reservoir's active drive mechanisms and their chronology. Seismic interpretation has provided the reservoir geometry and topography. The reservoir stratigraphy has been defined using log, core and seismic data. With well data as pilot points, the spatial distribution of the reservoir properties has been defined using geostatistics. The resulting geological model was used to construct a dynamic flow model that matched historical production and pressure data.. The reservoir's pressure and production behavior indicates a dominant compaction drive mechanism. The results of this work show that the reservoir performance is influenced not only by the available drive energy, but also by the spatial distribution of the different facies relative to well locations. The study has delineated the hydrocarbon bearing reservoir, quantified the different resource categories as STOIIP/GIIP = 19.8/26.2 mmstb/Bscf, ultimate recovery = 9.92/16.01 mmstb/Bscf, and reserves (as of 9/2001) = 1.74/5.99 mmstb/Bscf of oil and gas, respectively. There does not appear to be significant benefit to infill drilling or enhanced recovery operations.

The presented work is the application of recent methodologies on modeling and simulation of single stranded RNA viruses. We first present the methods of modeling RNA molecules using the coarse-grained modeling package, YUP. Coarse-grained models simplify complex structures such as viruses and let us study general behavior of the complex biological systems that otherwise cannot be studied with all-atom details. Second, we modeled the first all-atom T=3, icosahedral, single stranded RNA virus, Pariacoto virus (PaV). The x-ray structure of PaV shows only 35% of the total RNA genome and 88% of the capsid. We modeled both missing portions of RNA and protein. The final model of the PaV demonstrated that the positively charged protein N- terminus was located deep inside the RNA. We propose that the positively charged N- terminal tails make contact with the RNA genome and neutralize the negative charges in RNA and subsequently collapse the RNA/protein complex into an icosahedral virus. Third, we simulated T=1 empty capsids using a coarse-grained model of three capsid proteins as a wedge-shaped triangular capsid unit. We varied the edge angle and the potentials of the capsid units to perform empty capsid assembly simulations. The final model and the potential are further improved for the whole virus assembly simulations. Finally, we performed stability and assembly simulations of the whole virus using coarse-grained models. We tested various strengths of RNA-protein tail and capsid protein-capsid protein attractions in our stability simulations and narrowed our search for optimal potentials for assembly. The assembly simulations were carried out with two different protocols: co-transcriptional and post-transcriptional. The co-transcriptional assembly protocol mimics the assembly occurring during the replication of the new RNA. Proteins bind the partly transcribed RNA in this protocol. The post-transcriptional assembly protocol assumes that the RNA is completely transcribed in the absence of proteins. Proteins later bind to the fully transcribed RNA. We found that both protocols can assemble viruses, when the RNA structure is compact enough to yield a successful virus particle. The post-transcriptional protocol depends more on the compactness of the RNA structure compared to the co-transcriptional assembly protocol. Viruses can exploit both assembly protocols based on the location of RNA replication and the compactness of the final structure of the RNA.

The present work addresses issues related to the derivation of reduced models of atomistic systems, their statistical calibration, and their relation to atomistic models of materials. The reduced model, known in the chemical physics community as a coarse-grained model, is calibrated within a Bayesian framework. Particular attention is given to developing likelihood functions, assigning priors on coarse-grained model parameters, and using data from molecular dynamics representations of atomistic systems to calibrate coarse-grained models such that certain physically relevant atomistic observables are accurately reproduced. The developed Bayesian framework is then applied in three case studies of increasing complexity and practical application. A freely jointed chain model is considered first for illustrative purposes. The next example entails the construction of a coarse-grained model for a liquid heptane system, with the explicit design goal of accurately predicting a vapor-liquid transfer free energy. Finally, a coarse-grained model is developed for an alkylthiophene polymer that has been shown to have practical use in certain types of photovoltaic cells. The development therein employs Bayesian decision theory to select an optimal CG potential energy function. Subsequently, this model is subjected to validation tests in a prediction scenario that is relevant to the performance of a polyalkylthiophene-based solar cell. / text

Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第18986号 / 工博第4028号 / 新制||工||1620 / 31937 / 京都大学大学院工学研究科材料工学専攻 / (主査)教授 辻 伸泰, 教授 田中 功, 教授 乾 晴行 / 学位規則第4条第1項該当

Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第18987号 / 工博第4029号 / 新制||工||1620 / 31938 / 京都大学大学院工学研究科材料工学専攻 / (主査)教授 辻 伸泰, 教授 白井 泰治, 教授 松原 英一郎 / 学位規則第4条第1項該当

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