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作者： Furong Liao Yunnan Engineering Vocational College

With the rapid development and the popularity of the Internet,the field of education is also facing unprecedented changes and *** thesis explores the driving role of computer science and technology in education in the Internet era and the challenges it ***,the impact of the Internet on education and the close relationship between education and computer science are ***,the challenges faced by computer science and technology in education are analyzed,including issues of digital divide and inequality,privacy and security,technology dependency and quality of education,and the changing role of teachers and training ***,strategies to address these challenges are proposed,including policy development and regulation,reform and innovation of educational institutions,teacher training and professional development,and student and parent participation and *** study the advances and challenges of computer science and technology in education in the Internet age,which can better understand and respond to the changes and developments in education today.

关键词： Internet-era education computer science and technology Promotion and challenge

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Methods for compressible fluid simulation on GPUs using high-order finite differences

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computer PHYSICS COMMUNICATIONS 2017年 217卷 11-22页

作者： Pekkila, Johannes Vaisala, Miikka S. Kapyla, Maarit J. Kapyla, Petri J. Anjum, Omer Aalto Univ Dept Comp Sci ReSoLVE Ctr Excellence POB 15400 FI-00076 Aalto Finland Univ Helsinki Dept Phys Gustaf Hallstromin Katu 2aPOB 64 FI-00014 Helsinki Finland Max Planck Inst Sonnensyst Forsch Justus von Liebig Weg 3 D-37077 Gottingen Germany Leibniz Inst Astrophys Potsdam Sternwarte 16 D-11482 Potsdam Germany Nokia Solut & Networks Espoo Finland

We focus on implementing and optimizing a sixth-order finite-difference solver for simulating compressible fluids on a GPU using third-order Runge-Kutta integration. Since graphics processing units perform well in data-parallel tasks, this makes them an attractive platform for fluid simulation. However, high-order stencil computation is memory-intensive with respect to both main memory and the caches of the GPU. We present two approaches for simulating compressible fluids using 55-point and 19-point stencils. We seek to reduce the requirements for memory bandwidth and cache size in our methods by using cache blocking and decomposing a latency-bound kernel into several bandwidth-bound kernels. Our fastest implementation is bandwidth-bound and integrates 343 million grid points per second on a Tesla K40t GPU, achieving a 3.6x speedup over a comparable hydrodynamics solver benchmarked on two Intel Xeon E5-2690v3 processors. Our alternative GPU implementation is latency-bound and achieves the rate of 168 million updates per second. (C) 2017 Elsevier B.V. All rights reserved.

关键词： Computational techniques Fluid dynamics Finite difference methods in fluid dynamics Hydrodynamics Astrophysical applications computer science and technology

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Complex grid computing

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EUROPEAN PHYSICAL JOURNAL B 2005年第1期44卷 119-128页

作者： Costa, LD Travieso, G Ruggiero, CA Univ Sao Paulo Inst Fis Sao Carlos BR-13560970 Sao Carlos SP Brazil

This article investigates the functional properties of complex networks used as grid computing systems. Complex networks following the Erdos-Renyi model and other models with a preferential attachment rule ( with and without growth) or priority to the connection of isolated nodes are studied. Regular networks are also considered for comparison. The processing load of the parallel program executed on the grid is assigned to the nodes on demand, and the efficiency of the overall computation is quantified in terms of the parallel speedup. It is found that networks with preferential attachment allow lower computing efficiency than networks with uniform link attachment. At the same time, considering only node clusters of the same size, preferential attachment networks display better efficiencies. The regular networks, on the other hand, display a poor efficiency, due to their implied larger internode distances. A correlation is observed between the topological properties of the network, specially average cluster size, and their respective computing efficiency.

关键词： Structures and organization in complex systems computer science and technology World Wide Web, Internet Combinatorics, graph theory Networks and genealogical trees

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Statistical physics analysis of the computational complexity of solving random satisfiability problems using backtrack algorithms

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EUROPEAN PHYSICAL JOURNAL B 2001年第4期22卷 505-531页

作者： Cocco, S Monasson, R ENS Phys Theor Lab CNRS F-75005 Paris France Univ Illinois Dept Phys Chicago IL 60607 USA Univ Chicago James Franck Inst Chicago IL 60637 USA

The computational complexity of solving random 3-Satisfiability (3-SAT) problems is investigated using statistical physics concepts and techniques related to phase transitions, growth processes and (real-space) renormalization flows. 3-SAT is a representative example of hard computational tasks;it consists in knowing whether a set of alphaN randomly drawn logical constraints involving N Boolean variables can be satisfied altogether or not. Widely used solving procedures, as the Davis-Putnam-Loveland-Logemann (DPLL) algorithm, perform a systematic search for a solution, through a sequence of trials and errors represented by a search tree. The size of the search tree accounts for the computational complexity, i.e. the amount of computational efforts, required to achieve resolution. In the present study, we identify, using theory and numerical experiments, easy (size of the search tree scaling polynomially with N) and hard (exponential scaling) regimes as a function of the ratio alpha of constraints per variable. The typical complexity is explicitly calculated in the different regimes, in very good agreement with numerical simulations. Our theoretical approach is based on the analysis of the growth of the branches in the search tree under the operation of DPLL. On each branch, the initial 3-SAT problem is dynamically turned into a more generic 2+p-SAT problem, where p and 1 - p are the fractions of constraints involving three and two variables respectively. The growth of each branch is monitored by the dynamical evolution of alpha and p and is represented by a trajectory in the static phase diagram of the random 2+p-SAT problem. Depending on whether or not the trajectories cross the boundary between satisfiable and unsatisfiable phases, single branches or full trees are generated by DPLL, resulting in easy or hard resolutions. Our picture for the origin of complexity can be applied to other computational problems solved by branch and bound algorithms.

关键词： Computational methods in statistical physics and nonlinear dynamics Thermodynamics computer science and technology

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Criticality and universality in the unit-propagation search rule

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EUROPEAN PHYSICAL JOURNAL B 2006年第3期49卷 339-369页

作者： Deroulers, C Monasson, R CNRS ENS Phys Theor Lab F-75231 Paris 05 France

The probability P-success(alpha, N) that stochastic greedy algorithms successfully solve the random SATisfiability problem is studied as a function of the ratio alpha of constraints per variable and the number N of variables. These algorithms assign variables according to the unit-propagation (UP) rule in presence of constraints involving a unique variable (1-clauses), to some heuristic (H) prescription otherwise. In the infinite N limit, P-success vanishes at some critical ratio alpha(H) which depends on the heuristic H. We show that the critical behaviour is determined by the UP rule only. In the case where only constraints with 2 and 3 variables are present, we give the phase diagram and identify two universality classes: the power law class, where P-success[alpha(H) (1+epsilon N-1/3), N] similar to A(epsilon)/N-gamma;the stretched exponential class, where P-success[alpha(H) (1+epsilon N-1/3), N] similar to exp[-N-1/6 Phi(epsilon)]. Which class is selected depends on the characteristic parameters of input data. The critical exponent gamma is universal and calculated;the scaling functions A and Phi weakly depend on the heuristic H and are obtained from the solutions of reaction-diffusion equations for 1-clauses. Computation of some non-universal corrections allows us to match numerical results with good precision. The critical behaviour for constraints with > 3 variables is given. Our results are interpreted in terms of dynamical graph percolation and we argue that they should apply to more general situations where UP is used.

关键词： computer science and technology Fluctuation phenomena, random processes, noise, and Brownian motion Stochastic processes Systems obeying scaling laws

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On-chip clock technology for ultrafast digital superconducting electronics

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APPLIED PHYSICS LETTERS 2000年第25期76卷 3819-3821页

作者： Gupta, D Zhang, YM Hypres Inc Elmsford NY 10523 USA Conductus Inc Sunnyvale CA 94086 USA

An on-chip, low-jitter clock technology is essential for future multi-GHz digital electronics. In this article, we describe an on-chip clock technology for superconducting rapid single flux quantum (RSFQ) circuits built around an unshunted long Josephson junction (LJJ) oscillator that acts as a master clock source. The clock technology also includes clock frequency divider and selector circuits as well as a clock distribution network. These LJJ oscillators, implemented in linear and annular geometries using 3 mu m Nb technology, have quality factors of 10(6). This clock technology potentially has widespread use in 10-100 GHz superconducting digital circuits and systems, including analog-to-digital converters, time-to-digital converters, correlators, and processors for ultrahigh performance computers. (C) 2000 American Institute of Physics. [S0003-6951(00)04325-4].

关键词： Clocks Superconductivity Ultrafast technology computer science and technology Oscillators

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Optimization of reconfigurable optically interconnected systems for parallel computing

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JOURNAL OF PARALLEL AND DISTRIBUTED COMPUTING 2006年第2期66卷 238-247页

作者： Tissot, Y Russell, GA Symington, KJ Snowdon, JF Heriot Watt Univ Sch Engn & Phys Sci OIC Grp Edinburgh EH14 4AS Midlothian Scotland

This paper examines the use of an FPGA to circumvent the redundancy that may occur in free-space optically interconnected systems. We believe this paper presents solutions to the mapping of emitters and detectors onto an optoelectronic interface in order to perform an efficient connection topology. We report a novel versatile arrangement of the input/output optical interface and a straightforward algorithm for the implementation of a completely connected topology. Both utilize the reconfigurable potential of the FPGA to ease the design constraints on the optical system. (c) 2005 Elsevier Inc. All rights reserved.

关键词： optical interconnects optical communication systems computer science and technology computer interface

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Enabling a high throughput real time data pipeline for a large radio telescope array with GPUs

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computer PHYSICS COMMUNICATIONS 2010年第10期181卷 1707-1714页

作者： Edgar, R. G. Clark, M. A. Dale, K. Mitchell, D. A. Ord, S. M. Wayth, R. B. Pfister, H. Greenhill, L. J. Initiat Innovat Comp Cambridge MA 02138 USA Harvard Smithsonian Ctr Astrophys Cambridge MA 02138 USA Sch Engn & Appl Sci Cambridge MA 02138 USA

The Murchison Widefield Array (MWA) is a next-generation radio telescope currently under construction in the remote Western Australia Outback. Raw data will be generated continuously at 5 GiBs(-1), grouped into 8 s cadences. This high throughput motivates the development of on-site, real time processing and reduction in preference to archiving, transport and off-line processing. Each batch of 8 s data must be completely reduced before the next batch arrives. Maintaining real time operation will require a sustained performance of around 2.5 TFLOPs(-1) (including convolutions, FFTs, interpolations and matrix multiplications). We describe a scalable heterogeneous computing pipeline implementation, exploiting both the high computing density and FLOP-per-Watt ratio of modern GPUs. The architecture is highly parallel within and across nodes, with all major processing elements performed by GPUs. Necessary scatter-gather operations along the pipeline are loosely synchronized between the nodes hosting the GPUs. The MWA will be a frontier scientific instrument and a pathfinder for planned peta- and exa-scale facilities. (c) 2010 Elsevier B.V. All rights reserved.

关键词： Radio telescopes and instrumentation Heterodyne receivers Mathematical procedures and computer techniques computer science and technology

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COOPERATION OF LISTENER AND computer IN A RECOGNITION TASK - EFFECTS OF LISTENER RELIABILITY

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JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 1970年第2期47卷 480-+页

作者： CORCORAN, DW DENNETT, JL CARPENTER, A Medical Research Council Applied Psychology Unit Cambridge England

The purposes of the experiments were (a) to evaluate the influence of a computer display on the ability of listeners to recognize complex sounds, (b) to determine what effect variations in audio signal‐to‐noise (S/N) ratio would have on combined performance, and (c) to discover the strategy used by the listener to combine the computer with audio evidence. Thirty‐three Naval Ratings were tested over twelvesessions. In the scored sessions, listening performance, computer performance, and listener‐plus‐computer performance (C & Li) were assessed. It was found: (1) that the computer display was effective in producing better recognition; (2) that the higher the S/N ratio, the greater C & Li performance; (3) that the lower the S/N ratio, the greater the utilization of the computer information; (4) that the utilization of the computer evidence did not improve with training; and (5) that a relatively simple additive model described the method by which the listeners combined the two sources of evidence.

关键词： computer science and technology computer simulation Acoustical effects Acoustics computer modeling

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Stochastic dynamics of adaptive evolutionary search - A study on population-based incremental learning

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EUROPEAN PHYSICAL JOURNAL B 2001年第1期21卷 145-152页

作者： Galic, E Univ Wuerzburg Inst Phys D-97074 Wuerzburg Germany

In this paper the stochastic dynamics of adaptive evolutionary search, as performed by the optimization algorithm Population-Based Incremental Learning, is analyzed with physicists' methods for stochastic processes. The master equation of the process is approximated by van Kampen's small fluctuations assumption. It results in an elegant formalism which allows for an understanding of the macroscopic behaviour of the algorithm together with its fluctuations. We consider the search process to be adaptive since the algorithm iteratively reduces its mutation rate while approaching an optimum. On the one hand, it is this feature which allows the algorithm to quickly converge towards an optimum. On the other hand it results in the possibility to get trapped by a local optimum only. To arrive at a detailed understanding we discuss the influence of fluctuations, as caused by mutation, on this behaviour. Wie study the algorithm for rather small sytem sizes in order to gain an intuitive understanding of the algorithm's performance.

关键词： computer science and technology Dynamics of evolution Stochastic analysis methods (Fokker-Planck, Langevin, etc.)

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