As traditional textual passwords suffer from many known limitations, graphical passwords (GPs) are proposed as one promising alternative to complement the existing authentication systems. To obtain a large password sp...
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Analytic solutions for streamlines within tetrahedra are used to define operators that accurately and efficiently compute streamlines. The method presented here is based on linear interpolation, and therefore produces...
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Fully Polarimetric radar systems are capable of simultaneously transmitting and receiving in two orthogonal polarizations. Instantaneous radar polarimetry exploits both polarization modes of a dually-polarized radar t...
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ISBN:
(纸本)1424407850
Fully Polarimetric radar systems are capable of simultaneously transmitting and receiving in two orthogonal polarizations. Instantaneous radar polarimetry exploits both polarization modes of a dually-polarized radar transmitter and receiver on a pulse by pulse basis, and can improve the radar detection performance and suppress range sidelobes. In this paper, we extend the use of instantaneous radar polarimetry for radar systems with multiple dually-polarized transmit and receive antennas. Alamouti signal processing is used to coordinate transmission of Golay pairs of phase codes waveforms across polarizations and multiple antennas. The integration of multi-antenna signal processing with instantaneous radar polarimetry can further improve the detection performance, at a computational cost comparable to single channel matched filtering.
The reduced basis methodology is an efficient approach to solve parameterized discrete partial differential equations when the solution is needed at many parameter values. An offline step approximates the solution spa...
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作者：
Daitch, Samuel I.Spielman, Daniel A.Yale University
Department of Computer Science PO Box 208285 New HavenCT06520-8285 United States Yale University
Program in Applied Mathematics and Department of Computer Science PO Box 208285 New HavenCT06520-8285 United States
We present an algorithm for solving a linear system in a symmetric M-matrix. In particular, for n × n symmetric M-matrix M, we show how to find a diagonal matrix D such that DMD is diagonally-dominant. To compute...
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The discussion about how to put together Gentzen’s systems for classical and intuitionistic logic in a single unified system is back in fashion. Indeed, recently Prawitz and others have been discussing the so called ...
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Two problems in the use of computerized data base systems are: (1) How can we estimate the values for missing data? (2) How can we improve data integrity, that is, reduce the number of errors in the data? The tool tha...
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Electronics densification is continuing at an unrelenting pace at the server, rack, and facility level. With increasing facility density levels, airflow management has become a major challenge and concern. In an effor...
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Electronics densification is continuing at an unrelenting pace at the server, rack, and facility level. With increasing facility density levels, airflow management has become a major challenge and concern. In an effort to deal with the resulting thermal management challenges, manufacturers are increasingly turning to liquid cooling as a practical solution. The majority of manufacturers have turned to liquid-cooled enclosed racks or rear-door heat exchangers, in which chilled water is delivered to the racks. Some manufacturers are now looking to cold plate cooling solutions that take the heat directly off problem components, such as the CPUs, to get it directly out of the facility. This paper describes work done at the Pacific Northwest National Labs (PNNL) under a Department of Energy-funded program titled "Energy Smart Data Center." An 8.2 kW (27,980 Btu/h) rack of HP rx2600 2U servers has been converted from air-cooling to liquid spray cooling (CPUs only). The rack has been integrated into PNNL's main cluster and subjected to a suite of acceptance tests. Under the testing, the spray-cooled CPUs ran an average of 10°C (18°F) cooler than the air-cooled CPUs. Other peripheral devices, such as the memory D1MMs, ran an average of 8°C (14.4°F) cooler, and the power pod board was measured at 15°C(27°F) cooler. Since installation in July 2005, the rack has been undergoing a one-year uptime and reliability investigation. As part of the investigation, the rack has been subjected to monthly robustness testing and ongoing performance evaluation while running applications such as High Performance Linpack, parts of the NASA NPB-2 Benchmark Suite, and NW Chem. The rack has undergone three months' worth of robustness testing with no major events. Including the robustness testing, the rack uptime is at 95.54% over 299 days. While undergoing application testing, no computational performance differences have been observed between the liquid-cooled and standard air-cooled racks. A sm
Communities often represent key structural and functional clusters in networks. To preserve such communities, it is important to understand their robustness under network perturbations. Previous work in community robu...
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Communities often represent key structural and functional clusters in networks. To preserve such communities, it is important to understand their robustness under network perturbations. Previous work in community robustness analysis has focused on studying changes in the community structure as a response of edge rewiring and node or edge removal. However, the impact of increasing connectivity on the robustness of communities in networked systems is relatively unexplored. Studying the limits of community robustness under edge addition is crucial to better understanding the cases in which density expands or false edges erroneously appear. In this paper, we analyze the effect of edge addition on community robustness in synthetic and empirical temporal networks. We study two scenarios of edge addition: random and targeted. We use four community detection algorithms, Infomap, Label Propagation, Leiden, and Louvain, and demonstrate the results in community similarity metrics. The experiments on synthetic networks show that communities are more robust when the initial partition is stronger or the edge addition is random, and the experiments on empirical data also indicate that robustness performance can be affected by the community similarity metric. Overall, our results suggest that the communities identified by the different types of community detection algorithms exhibit different levels of robustness, and so the robustness of communities depends strongly on the choice of detection method.
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