We focus on an optimization problem on parameterized surfaces of genus one. In particular we trade off the penalty functions for bending a toroidal path and for applying a twist to it and aim to find local minima of this cost function. This analysis forms a key element in demonstrating the different regular homotopy classes of tori. A generalization of this surface optimization, which considers curvature as well as any shearing of its parameter grid, may be used to find the most optimal direct path from an arbitrary closed manifold of genus one into one of the four basic representatives of the four regular homotopy classes of tori.

关键词：参数表面；环形循环；弯曲能量；梯度下降；定期同伦

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Actual communication systems have only finite channel diversity, and thus the practical implications of interference alignment are uncertain: Just how much channel diversity is required in order to get substantial benefit from interference alignment? The first part of this thesis focuses on this question. Our first result characterizes the degrees of freedom for the three-user interference channel as a function of time or frequency diversity. We next focus on spatial diversity, in the form of multiple antennas at transmitters and receivers.The second part of this thesis studies DNA sequencing from an information theory pointof-view. DNA sequencing is the basic workhorse of modern day biology and medicine.

关键词：无线通信；干扰；自由度

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In this work, we utilize experimental data from a monkey subject performing closed-loop control of a 2D cursor BMI and show that the presence of certain dynamical properties correlate with performance loss. We also show that other dynamical properties represent tradeoffs between naturally competing objectives, such as speed versus accuracy. These empirical findings demonstrate the need to eliminate detrimental dynamics by accounting for the feedback control strategy employed by the user, as well as the need to fine-tune plant dynamics to optimize task-specific performance tradeoffs. To this end, we develop general-purpose tools for designing BMI plant dynamics. Using these tools, we show two different ways to improve accuracy and hold performance at the expense of speed.

关键词：脑机接口；闭环性；动力学；精度；性能；工具

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The CSD describes the probability of sampling an individual with a particular genomic sequence, provided that a collection of individuals from the population, and their corresponding sequences, has already been observed. Critically, the true CSD is generally inaccessible, and it is therefore necessary to use an approximate CSD in its place; such an approximate CSD is ideally both accurate and computationally efficient. In this thesis, we undertake a theoretical and algorithmic investigation of the CSD for coalescent models incorporating mutation, homologous (crossover) recombination, and population structure with migration.

关键词：算法；统计；联合模型；CSD；计算效率

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In this paper we introduce CARRQR, a communication avoiding rank revealing QR factorization with tournament pivoting. We show that CARRQR reveals the numerical rank of a matrix in an analogous way to QR factorization with column pivoting (QRCP). Although the upper bound of a quantity involved in the characterization of a rank revealing factorization is worse for CARRQR than for QRCP, our numerical experiments on a set of challenging matrices show that this upper bound is very pessimistic, and CARRQR is an e ective tool in revealing the rank in practical problems.Our main motivation for introducing CARRQR is that it minimizes data transfer, modulo poly-logarithmic factors, on both sequential and parallel machines, while previous factorizations as QRCP are communication sub-optimal and require asymptotically more communication than CARRQR.Hence CARRQR is expected to have a better performance on current and future computers, where commmunication is a major bottleneck that highly impacts the performance of an algorithm.

关键词：数据传输；算法；QR；CARRQR；数值等级

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In the Traditional Chinese Medicine, doctors diagnose patients by reading pulses from their wrists, so as to give out proper receipts of herbs curing patients across generations.In our capstone project, a mobile app with sensor gadget has been developed to detect, gather, convert and process pulse signals, and offer users valuable health suggestions. To get accurate pulse signals from wrists, several sensor prototypes have been developed and prototyped. The best-performing sensor, a piezoelectric sensor, is chosen and implemented in detail. Pulse data was processed to extract a stable pulse signal, in aspects of: amplitude of peak signal, and signal time period. From this information the app makes 'diagnoses' about the stress level and health condition of different organs of users. Finally, our mobile app delivers feedback to users, guiding them to healthier lives. The price of the Dr. Chi hardware, and mobile app is projected to be 30 dollars, and so promises to be orders of magnitudes more affordable than existing products for convenient health diagnoses.

关键词：传统中医；脉冲信号；传感器；移动应用程序

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when can one say that a certain dataflow model faithfully captures a given piece of hardware? The question is investigated in this paper. Finite state machines with synchronous semantics are used to model hardware. Asynchronous processes communicating via queues are employed for dataflow. A conformance relation between these two heterogeneous models of computation is developed that preserves performance properties such as worst-case throughput and latency.

关键词：数据流模型；同步语义模型；吞吐量；硬件

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报告包括2013年11月上半月通信行业的政策监管、行业要闻、区域要闻、企业要闻、海外要闻。

关键词：通信；政策；运营商；垃圾短信；软件；智能交通；大数据

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Debugging large-scale, data-intensive, distributed applications running in a datacenter (“datacenter applications”) is complex and time-consuming. The key obstacle is non-deterministic failures—hard-to-reproduce program misbehaviors that are immune to traditional cyclic debugging techniques. Datacenter applications are rife with such failures because they operate in highly non-deterministic environments: a typical setup employs thousands of nodes, spread across multiple datacenters, to process terabytes of data per day. In these environments, existing methods for debugging non-deterministic failures are of limited use. They either incur excessive production overheads or don’t scale to multi-node, terabyte-scale processing. To help remedy the situation, we have built a new deterministic replay tool. Our tool, called DCR, enables the reproduction and debugging of non-deterministic failures in production datacenter runs. The key observation behind DCR is that debugging does not always require a precise replica of the original datacenter run. Instead, it often suffices to produce some run that exhibits the original behavior of the control-plane—the most error-prone component of datacenter applications. DCR leverages this observation to relax the determinism guarantees offered by the system, and consequently, to address key requirements of production datacenter applications: lightweight recording of long running programs, causally consistent replay of large-scale clusters, and out-of-the box operation with existing, real world applications running on commodity multiprocessors.

关键词：分布式应用程序；数据中心应用程序；故障排除；数据中心；确定性重放工具（DCR）

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The Software-Defined Networking (SDN) paradigm is typically applied to data center and enterprise networks. We argue that SDN is also promising for rural wireless networks, especially those in developing regions. Operating a rural network in the developing world means coping with unpredictability, low profit margins, and resource constraints; the increased flexibility and simplified management that software-defined networks provide are a major benefit in this context.

关键词：软件定义网络（SDN）；数据中心；企业网络；网络虚拟化；网络基础设施

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