Cyber physical system (CPS) are interconnection of computation, networking and physical elements. Modern CPS are distributed, networked and safety-critical systems and architectural design of such systems with fault tolerance and performance constraints is a challenging task. In this thesis, we address the problem of synthesizing safety-critical cyber-physical system architectures to minimize a cost function while guaranteeing the desired reliability. We cast it as an optimization problem with the component cost as the objective and the performance and reliability requirements as the constraints. 

关键词：网络物理系统（CPS）;网络安全;容错能力

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Vacuum encapsulation of RF disk and beam resonators is often needed to maintain high quality factor and frequency stability. Conventionally, this is performed at the wafer level by anodic, eutectic, fusion, or glass frit bonding. After wafer dicing, packaging proceeds with die attach to the package substrate and plastic over molding. This process leads to many contacts between materials of different coefficients of thermal expansion (CTE) resulting in packageinduced stress. The focus of this work is to determine the effect of this stress on the temperature stability of micromechanical resonators via finite element analysis (FEA), for applications that do not require attachment to a printed circuit board, such as the sensors in the original vision of Smart Dust.

关键词：射频磁盘;谐振器;热膨胀系数（CTE）

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Shark is a research data analysis system built on a novel coarse-grained distributed shared-memory abstraction. Shark pairs query processing with deep data analysis, providing a unified system for easy data manipulation using SQL and pushing sophisticated analysis closer to its data. It scales to thousands of nodes in a fault-tolerant manner. Shark can answer queries over 40 times faster than Apache Hive and run machine learning programs on large datasets over 25 times faster than equivalent MapReduce programs on Apache Hadoop. Unlike previous systems, Shark shows that it is possible to achieve these speedups while retaining a MapReduce-like execution engine, with the fine-grained fault tolerance properties that such an engine provides. Shark additionally provides several extensions to its engine, including table and column-level statistics collection as well as a cost-based optimizer, both of which we describe in depth in this paper. Cost-based query optimization in some cases improves the performance of queries with multiple joins by orders of magnitude over Hive and over 2 times compared to previous versions of Shark.

关键词：粗粒度；分布式存储；SQL；查询优化

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Modeling all aspects of a complex system within a single model is a difficult, if not impossible, task. Multi-view modeling is a methodology where different aspects of the system are captured by different models, or views. A key question then is consistency: if different views of a system have some degree of overlap, how can we guarantee that they are consistent, i.e., that they do not contradict each other? In this paper we formulate this and other basic problems in multi-view modeling within an abstract formal framework. We then instantiate this framework in a discrete, finite-state system setting, and study how some key verification and synthesis problems can be solved in that setting.

关键词：多视图模型；建模；三维物体识别；离散系统

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In this thesis, we investigate the switching dynamics in thin film ferroelectrics. We have developed a phase field model that describes the physics of polarization dynamics at the microscopic scale. A number of efficient numerical methods have been applied for achieving massive parallelization of all the calculation steps. Conformally mapped elements, node wise assembly and prevention of dynamic loading minimized the communication between processors and increased the parallelization efficiency. With these improvements, we have reached the experimental scale - a significant step forward compared to the state of the art thin film ferroelectric switching dynamics models. Using this model, we elucidated the switching dynamics on multiple surfaces of the multiferroic material BFO. We also calculated the switching energy of scaled BFO islands. Finally, we studied the interaction of domain wall propagation with misfit dislocations in the thin film.

关键词：开关动力学；并行；相场；薄膜；铁电材料

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The purpose of this report is to document the first complete attempt at the design of a high-level programming language for timed systems called act. We define the lexical grammar and the syntactic grammar of act, and include an example of a simple actor written in act, demonstrating some of the syntactic features of the language.

关键词：编程语言；句法特征；词汇语法

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Recent work identified the fundamental limits on the information requirements in terms of read length and coverage depth required for successful de novo genome reconstruction from shotgun sequencing data, based on the idealistic assumption of no errors in the reads (noiseless reads). In this work, we show that even when there is noise in the reads, one can successfully reconstruct with information requirements close to the noiseless fundamental limit. A new assembler, X-phased Multibridging, is designed based on a probabilistic model of the genome. It is shown through analysis to perform well on the model, and through simulations to perform well on real genomes.

关键词：序列拼接；de novo序列拼接；Shotgun技术；测序技术

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There is a fundamental tradeoff between conductance and subthreshold swing voltage in tunnel field effect transistors that achieve a sharp turn off by modulating the tunnel barrier thickness. At high conductivities, the voltage bias has little control over the tunneling probability. Unfortunately, this results in a poor subthreshold swing voltage at high conductivities. In tunnel field effect transistors, the best sub 60mV/decade results occur only at very low current densities around 1nA/μm. At higher current densities the subthreshold swing voltage is observed to be much worse than 60mV/decade. We show that this is an inherent problem in quantum barrier thickness modulation, and that a different mechanism, band-edge energy filtering, is needed.

关键词：隧道场效应晶体管；亚阈值；势垒厚度

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This paper derives tradeoffs between three basic costs of a parallel algorithm: synchronization, data movement, and computational cost. Our theoretical model counts the amount of work and data movement as a maximum of any execution path during the parallel computation. By considering this metric, rather than the total communication volume over the whole machine, we obtain new insight into the characteristics of parallel schedules for algorithms with non-trivial dependency structures. The tradeoffs we derive are lower bounds on the execution time of the algorithm which are independent of the number of processors, but dependent on the problem size. Therefore, these tradeoffs provide lower bounds on the parallel execution time of any algorithm computed by a system composed of any number of homogeneous components each with associated computational, communication, and synchronization payloads. We first state our results for general graphs, based on expansion parameters, then we apply the theorem to a number of specific algorithms in numerical linear algebra, namely triangular substitution, Gaussian elimination, and Krylov subspace methods. Our lower bound for LU factorization demonstrates the optimality of Tiskin’s LU algorithm [24] answering an open question posed in his paper, as well as of the 2.5D LU algorithm which has analogous costs. We treat the computations in a general manner by noting that the computations share a similar dependency hypergraph structure and analyzing the communication requirements of lattice hypergraph structures.

关键词：并行算法；同步；通信；数据移动

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We consider certain spaces of linear signals equipped with a standard prefix relation and a suitably defined generalized distance function. We introduce a new class of abstract structures, which we call generalized ultrametric semilattices, and prove a representation theorem stating that every generalized ultrametric semilattice with a totally ordered distance set is isomorphic to a space of that kind. It follows that the formal definition of generalized ultrametric semilattices with totally ordered distance sets constitutes an axiomatization of the first-order theory of those spaces.

关键词：线性信号；半格；广义距离函数

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