A parallel algorithm has perfect strong scaling if its running time on P processors is linear in 1=P, including all commu-nication costs. Distributed-memory parallel algorithms for matrix multiplication with perfect strong scaling have only recently been found. One is based on classical matrix multi-plication (Solomonik and Demmel, 2011), and one is based on Strassen's fast matrix multiplication (Ballard, Demmel, Holtz, Lipshitz, and Schwartz, 2012). Both algorithms scale perfectly, but only up to some number of processors where the inter-processor communication no longer scales.

关键词：处理器；快速矩阵乘法；通信成本

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Blocked matrix multiplication algorithms such as Cannon's algorithm and SUMMA havea 2-dimensional communication structure. We introduce a generalized 'Split-Dimensional' version of Cannon's algorithm (SD-Cannon) with higher-dimensional and bidirectional communication structure.This algorithm is useful for higher-dimensional torus interconnects that can achieve more injection bandwidth than single-link bandwidth. On a bidirectional torus network of dimension d, SD-Cannon can lower the algorithmic bandwidth cost by a factor of up to d. With rectangular collectives, SUMMA also achieves the lower bandwidth cost but has a higher latency cost. We use Charm++ virtualization to eciently map SD-Cannon on unbalanced and odd-dimensional torus network partitions. Our per-formance study on Blue Gene/P demonstrates that an MPI version of SD-Cannon can exploit multiple communication links and improve performance.

关键词：阻塞矩阵乘法算法；二维通信结构；高维环连接；带宽成本

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This paper summarizes the progress that has been made in the development of the Fission Power System Technology Demonstration Unit (TDU). The reactor simulator core and Annular Linear Induction Pump have been fabricated and assembled into a test loop at the NASA Marshall Space Flight Center. A 12 kWe Power Conversion Unit (PCU) is being developed consisting of two 6 kWe free-piston Stirling engines. The two 6 kWe engines have been fabricated by Sunpower Inc. and are currently being tested separately prior to integration into the PCU. The Facility Cooling System (FCS) used to reject convertor waste heat has been assembled and tested at the NASA Glenn Research Center (GRC). The structural elements, including a Buildup Assembly Platform (BAP) and Upper Truss Structure (UTS) have been fabricated, and will be used to test cold-end components in thermal vacuum prior to TDU testing. Once all components have been fully tested at the subsystem level, they will be assembled into an end-to-end system and tested in thermal vacuum at GRC.

关键词：电力系统；裂变

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The information technology (IT) world has changed fundamentally and drastically from running software applications on a single computer with a single CPU to now running software as services in distributed and parallel computing environment. Power system operation has been also shifted from being solely based on off-line planning study to more and more real-time market-driven. Facing these challenges, we will discuss in this chapter how to design power system analysis and simulation software to take advantage of the new IT technologies and to meet the real-time application requirements, using the InterPSS project as a concrete example.

关键词：电力系统；仿真

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The grasp and the task are two actions closely related. A grasp is always performed with a purpose in mind, and the execution of a task requires a suitable task-oriented grasp in most of the cases. The grasp does not need to be prehensile. Most of our daily life manipulation is done trough non-prehensile grasps. Interaction with the environment is always preceded by a contact configuration, as a result of a prehensile or non-prehensile grasp. And vice versa, a contact configuration on one object is always followed by a desired motion according to the task: lift, push, etc.

关键词：传感器；互动框架

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In April 2009, NASA Glenn Research Center (GRC) formed an integrated product team (IPT) to develop a Small Radioisotope Power System (SRPS) utilizing a single Advanced Stirling Convertor (ASC) with passive balancer for possible use by the International Lunar Network (ILN) program. The ILN program is studying the feasibility of implementing a multiple node seismometer network to investigate the internal lunar structure. A single ASC produces approximately 80We and could potentially supply sufficient power for that application. The IPT consists of Sunpower, Inc., to provide the single ASC with balancer, The Johns Hopkins University Applied Physics Laboratory (JHU/APL) to design an engineering model Single Convertor Controller (SCC) for an ASC with balancer, and NASA GRC to provide technical support to these tasks and to develop a simulated lunar lander test stand. A controller maintains stable operation of an ASC. It regulates the alternating current produced by the linear alternator of the convertor, provides a specified output voltage, and maintains operation at a steady piston amplitude and hot end temperature. JHU/APL also designed an ASC dynamic engine/alternator simulator to aid in the testing and troubleshooting of the SCC. This paper describes the requirements, design, and development of the SCC, including some of the key challenges and the solutions chosen to overcome those issues. In addition, it describes the plans to analyze the effectiveness of a passive balancer to minimize vibration from the ASC, characterize the effect of ASC vibration on a lunar lander, characterize the performance of the SCC, and integrate the single ASC, SCC, and lunar lander test stand to characterize performance of the overall system.

关键词：电力系统；同位素

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High-speed extended term (HSET) time domain simulation (TDS) is intended to provide very fast computational capability to predict extended-term dynamic system response to disturbances and identify corrective actions. The extended-term dynamic simulation of a power system is valuable because it provides ability for the rigorous evaluation and analysis of outages which may include cascading. It is important for secure power grid expansion, enhances power system security and reliability, both under normal and abnormal conditions. In this chapter the design of the envisioned future dynamic security assessment processing system (DSAPS) is presented where HSET-TDS forms the core module. The power system is mathematically represented by a system of differential and algebraic equations (DAEs). These DAEs arise out of the modeling of the dynamic components such as generators, exciters, governors, automatic generation control, load tap changers, induction motors, network modeling and so on. To provide very fast computational capability within the HSET-TDS, this chapter motivates the need for high performance computing (HPC) for power system dynamic simulations through detailed modeling of power system components and efficient numerical algorithms to solve the resulting DAEs. The developed HSET-TDS is first validated for accuracy against commercial power simulators (PSSE, DSA Tools, Power-World) and then it is compared for computational efficiency. The chapter investigates some of the promising direct sparse linear solver for fast extended term time domain simulation and makes recommendation for the modern power grid computations. The results provide very important insights with regards to the impact of the different numerical linear solver algorithms for enhancing the power system TDS.

关键词：电力系统；动态

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The intent of this chapter is to introduce side channel attacks as a significant threat for wireless sensor networks, since in such systems the individual sensor node can be accessed physically and analysed afterwards. Even though such attacks are known for some years, they have never been specifically considered before in the area of WSNs (Wireless Sensor Networks).

关键词：无线传感器；网络安全；反侧信道攻击

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This paper presents a study were the Rough Set Theory and Data Mining Technique are applied to the electrical power system. The Data Mining technique classifies the system operation in four possible states: normal, alert, emergency (emergency I and emergency II). The states, that correspond to the normal state can be classified as secure and insecure the remaining ones. In this security studies, the overloads in transmition lines and the violation of the voltage limits are used to classify and rank these contingencies. This technique was applied to the 118IEEE busbar test power network and the results obtained are analyzed. Finally, some conclusions that provide a valuable contribution to the understanding of the power system security analysis are pointed out.

关键词：电力系统；数据挖掘技术

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Tidal energy, offshore wind energy, and onshore wind energy can be converted to electricity at a central ground location by converting their respective energies into high-pressure hydraulic flows that are transmitted to a system of hydraulic generators by high-pressure pipelines. The high-pressure flows are then efficiently converted to electricity by a central hydraulic power plant, and the low-pressure outlet flow is returned. All gears and submerged electronics are completely eliminated (JPL/Caltech patents granted and pending). The Department of Energy (DOE) is presently supporting a project led by Sunlight Photonics to demonstrate a 15 kW tidal hydraulic power generation system in the laboratory. Sunlight Photonics will issue a separate report on this successful experimental phase. Another portion of this DOE project involves sizing and costing a 15 MW commercial tidal energy plant, which is the subject of this Final Report. For this task, Atlantis Resources Corporation s demonstrated 18-m diameter tidal blades operate in a nominal 2.6 m/sec tidal flow to produce one MW per set of tidal blades. Fifteen blade units are submerged in a deep tidal area, such as Maine s Western Passage. Each set of blades is attached to commercial-offthe-shelf (COTS) Hagglund radial piston pumps, and all pumps are connected to a hig-hpressure (20 MPa, 2900 psi) line that is 35 cm ID. High-pressure HEPG fluid is transported 500 meters to a parallel series of onshore, COTS axial piston hydraulic generators. HEPG is an environmentally-friendly, biodegradable, water-miscible fluid. The total cost of producing energy with this tidal power plant is estimated to be $0.15/kW-hr, which is between the cost of wind energy and solar energy. Hydraulic adaptations to Ocean Renewable Power Company s (ORPC s) cross-flow tidal turbines are also discussed. Costs to convert a submerged ORPC tidal system to a hydraulic device with onshore power generation are about 50 cents per watt, minus the cost of ORPC s expensive submerged generators, which would be entirely removed. Although not originally planned, applications of Hydraulic Energy Transfer (HET) for wind energy have also been added to this report. For wind energy that is onshore or offshore, a gearless, high-efficiency, COTS, radial piston pump can replace each set of troublesome, top-mounted gear-generators for conventional wind turbine systems. Environmentally friendly HEPG fluid is then pumped to a central system of easily serviceable ground generators, which consist of a parallel series of axial piston hydraulic generators. Total hydraulic/electrical efficiency of 81is close to that of conventional wind turbines at full-rated wind speeds. Total HET efficiencies increase at slower speeds, however, while conventional wind turbine efficiencies decrease significantly. In addition, all troublesome gears are eliminated for HET wind and tidal energy systems.

关键词：电力系统；潮汐；风力

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