摘要:

The Information Age is transforming our economy and our lives. In its pathbreaking 1999 report to President Clinton, the Presidential Information Technology Advisory Committee (PITAC) outlined the ten crucial ways that new technologies are transforming society in the U.S. It is clear that the Federal government will need to provide the critical R&D investments that will help retain and bolster the U.S. technological lead in the 21st century. These investments will also support efforts to make new technologies and their benefits available to all U.S. citizens. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1405255

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

C++ supports several styles (“multiple paradigms”) of programming. This allows great flexibility, notational convenience, maintainability, and close-to-optimal performance. Programmers who don’t know the basic native C++ styles and techniques “speak” C++ with a thick accent, limiting themselves to relatively restrictive pidgin dialects. Here, I present language features such as classes, class hierarchies, abstract classes, and templates, together with the fundamental programming styles they support. In particular, I show how to provide generic algorithms, function objects, access objects, and delayed evaluation as needed to build and use flexible and efficient libraries. The aim is to give an idea of what’s possible to provide, and some understanding of the fundamental techniques of modern C++ libraries. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1405256

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

During the coming decade, high energy physics experiments at the Fermilab Tevatron and around the globe will use very sophisticated equipment to record unprecedented amounts of data in the hope of making major discoveries that may unravel some of Nature’s deepest mysteries. The discovery of the Higgs boson and signals of new physics may be around the corner. The use of advanced analysis techniques will be crucial in achieving these goals. I will discuss some of the novel methods of analysis that could prove to be particularly valuable for finding evidence of any new physics, for improving precision measurements and for exploring parameter spaces of theoretical models. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1405257

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

Rather than attempting to cover a wide range of statistical problems. I shall concentrate on four topics: 1) The argument between Bayesians and Frequentists, 2) A paradox in comparing data with two hypotheses; 3) The CLs method used in the search for the Higgs at CERN, 4) The MLBZ method of using data to estimate some of the systematic effects in measuring the W boson’s mass. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1405258

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

We present a short overview of neuromorphic hardware and some of the physics projects making use of such devices. As a concrete example we describe an innovative project within the H1-Experiment at the electron-proton collider HERA, instrumenting hardwired neural networks as pattern recognition machines to discriminate between wanted physics and uninteresting background at the trigger level. The decision time of the system is less than 20 microseconds, typical for a modern second level trigger. The neural trigger has been successfully running for the past four years and has turned out new physics results from H1 unobtainable so far with other triggering schemes. We describe the concepts and the technical realization of the neural network trigger system, present the most important physics results, and motivate an upgrade of the system for the future high luminosity running at HERA. The upgrade concentrates on “intelligent preprocessing” of the neural inputs which help to strongly improve the networks’ discrimination power. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1405259

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

The evaluation of quantum corrections in the theory of the electroweak and strong interactions via higher-order Feynman diagrams requires complicated and laborious calculations, which however can be structured in a strictly algorithmic way. These calculations are ideally suited for the application of computer algebra systems, and computer algebra has proven to be a very valuable tool in this field already over several decades. It is sketched how computer algebra is presently applied in evaluating the predictions of the electroweak theory with high precision, and some recent results obtained in this way are summarized. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1405260

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

The term “Grid Computing” refers to the use, for computational purposes, of emerging distributed Grid infrastructures: that is, network and middleware services designed to provide on-demand and high-performance access to all important computational resources within an organization or community. Grid computing promises to enable both evolutionary and revolutionary changes in the practice of computational science and engineering based on new application modalities such as high-speed distributed analysis of large datasets, collaborative engineering and visualization, desktop access to computation via “science portals,” rapid parameter studies and Monte Carlo simulations that use all available resources within an organization, and online analysis of data from scientific instruments. In this article, I examine the status of Grid computing circa 2000, briefly reviewing some relevant history, outlining major current Grid research and development activities, and pointing out likely directions for future work. I also present a number of case studies, selected to illustrate the potential of Grid computing in various areas of science. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1405261

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

Scalable space-time multiresolution algorithms implemented on massively parallel computers enable large-scale molecular dynamics simulations involving up to a billion atoms, which are applied to the study of nanosystems of great technological importance. These include sintering, structure, and mechanical properties of nanostructured ceramics and nanocomposites, structural transformation in semiconductor nanocrystals, nanoindentation, and oxidation of metallic nanoparticles. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1405262

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

A neural network solution for a complicated experimental High Energy Physics problem is described. The method is used to reconstruct the momentum and charge of muons produced in collision of particles in the ATLAS detector. The information used for the reconstruction is limited to the output of the outer layer of the detector, after the muons went through strong and inhomogeneous magnetic field that have bent their trajectory. It is demonstrated that neural network solution is efficient in performing this task. It is shown that this mechanism can be efficient in rapid classification as required in triggering systems of the future particle accelerators. The parallel processing nature of the network makes it relevant for hardware realization in the ATLAS triggering system. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1405263

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

The neural network first level trigger for the DIRAC experiment at CERN is presented. Both the neural network algorithm used and its actual hardware implementation are described. The system uses the fast plastic scintillator information of the DIRAC spectrometer. In 210 ns it selects events with two particles having low relative momentum. Such events are selected with an efficiency of more than 0.94. The corresponding rate reduction for background events is a factor of 2.5. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1405264

出版商:AIP    

年代:1901

数据来源: AIP