Volunteer computing
Computers continue to get faster exponentially, but the computational demands of science are growing even faster. Extreme requirements arise in at least three areas.
By David P. Anderson, March 2010
Articles Tagged: Performance
Articles & Features
Clouds at the crossroads
Despite its promise, most cloud computing innovations have been almost exclusively driven by a few industry leaders, such as Google, Amazon, Yahoo!, Microsoft, and IBM. The involvement of a wider research community, both in academia and industrial labs, has so far been patchy without a clear agenda. In our opinion, the limited participation stems from the prevalent view that clouds are mostly an engineering and business-oriented phenomenon based on stitching together existing technologies and tools.
By Ymir Vigfusson, Gregory Chockler, March 2010
Scientific workflows and clouds
In recent years, empirical science has been evolving from physical experimentation to computation-based research. In astronomy, researchers seldom spend time at a telescope, but instead access the large number of image databases that are created and curated by the community [42]. In bioinformatics, data repositories hosted by entities such as the National Institutes of Health [29] provide the data gathered by Genome-Wide Association Studies and enable researchers to link particular genotypes to a variety of diseases.
By Gideon Juve, Ewa Deelman, March 2010
Are your friends who they say they are?
How sure are you that your friends are who they say they are? In real life, unless you are the target of some form of espionage, you can usually be fairly certain that you know whom your friends are because you have a history of shared interests and experiences. Likewise, most people can tell, just by using common sense, if someone is trying to sell them on a product, idea, or candidate. When we interact with people face-to-face, we reevaluate continuously whether something just seems off based on body language and other social and cultural cues.
By Roya Feizy, Ian Wakeman, Dan Chalmers, December 2009
Towards a user-friendly semantic formalism for natural language generation
Computational semantics has become an interesting and important branch of computational linguistics. Born from the fusion of formal semantics and computer science, it is concerned with the automated processing of meaning associated with natural language expressions [2]. Systems of semantic representation, hereafter referred to as semantic formalisms, exist to describe meaning underlying natural language expressions. To date, several formalisms have been defined by researchers from a number of diverse disciplines including philosophy, logic, psychology and linguistics. These formalisms have a number of different applications in the realm of computer science. For example, in machine translation a sentence could be parsed and translated into a series of semantic expressions, which could then be used to generate an utterance with the same meaning in a different language [14]. This paper presents two existing formalisms and examines their user-friendliness. Additionally, a new form of semantic representation is proposed with wide coverage and user-friendliness suitable for a computational linguist.
By Craig Thomas, December 2008
Geometric and path tracing methods for simulating light transport through volumes of water particles
The visual appearance of volumes of water particles, such as clouds, waterfalls, and fog, depends both on microscopic interactions between light rays and individual droplets of water, and also on macroscopic interactions between multiple droplets and paths of light rays. This paper presents a model that builds upon a typical single-scattering volume renderer to correctly account for these effects. To accurately simulate the visual appearance of a surface or a volume of particles in a computer-generated image, the properties of the material or particle must be specified using a Bidirectional Reflectance Distribution Function (BRDF), which describes how light reflects off of a material, and the Bidirectional Transmittance Distribution Function (BTDF), which describes how light refracts into a material. This paper describes an optimized BRDF and BTDF for volumes of water droplets, which takes their geometry into account in order to produce well-known effects, such as rainbows and halos. It also describes how a multiple-scattering path tracing volume integrator can be used to more accurately simulate macroscopic light transport through a volume of water, creating a more "cloudlike" appearance than a single-scattered volume integrator. This paper focuses on replicating the visual appearance of volumes of water particles, and although it makes use of physical models, the techniques presented are not intended to be physically accurate.
By James Hegarty, September 2008
Comparison of input devices and displays for protein visualization
By Elke Moritz, Thomas Wischgoll, Joerg Meyer, December 2005
Introduction to programming shared-memory and distributed-memory parallel computers
By Cory Quammen, October 2005
Game-state fidelity across distributed interactive games
By Aaron McCoy, Declan Delaney, Tomas Ward, October 2005
An interaction model for mobile agent services using social networks
By Vishakh, Nicholas Urrea, Tadashi Nakano, Tatsuya Suda, August 2005
Overcoming misbehavior in mobile ad hoc networks
By George Athanasiou, Leandros Tassiulas, Gregory S. Yovanof, August 2005
Experimental mobile gateways
By Premshree Pillai, August 2005
Game-state fidelity across distributed interactive games
By Aaron McCoy, Declan Delaney, Tomas Ward, June 2003
Q2ADPZ* an open source, multi-platform system for distributed computing
By Zoran Constantinescu, Pavel Petrovic, December 2002
Building an MPI cluster
By Donald C. Bergen, Boise P. Miller, August 2002
Optimizing application performance
By M. Tyler Maxwell, Kirk W. Cameron, August 2002
Evolutionary learning in mobile robot navigation
By Cory Quammen, December 2001
Connector
By Kostas Pentikousis, July 2001
Introduction to mobile computing
By Sandeep Jain, December 2000
Can TCP be the transport protocol of the 21st century?
By Kostas Pentikousis, December 2000
Macromedia director as a prototyping and usability testing tool
By Stephanie Ludi, July 2000
Graphic libraries for Windows programming
By M. Carmen Juan Lizandra, June 2000
The many dimensions of the software process
By Sebastián Tyrrell, June 2000
The world of data compression
By Eric Scheirer, March 2000
In memory of David Huffman
By Kevin Fu, March 2000
Objective viewpoint
By Matt Tucker, March 2000
Design of an interactive tutorial for logic and logical circuits
By Jeremy Kindy, John Shuping, Patricia Yali Underhill, David John, March 2000
Image compression—from DCT to wavelets
By Subhasis Saha, March 2000
Prefix compression of sparse binary strings
Note from ACM Crossroads: Due to errors in the layout process for printing on paper, the version of this article in the printed magazine contained several errors (mostly related to superscripts). This HTML version is the accurate version. Please refer to this HTML version instead of the printed version and accept our apologies for any inconvenience.
By David Salomon, March 2000
A hierarchical error controlled octree data structure for large-scale visualization
By Dmitriy V. Pinskiy, Joerg Meyer, Bernd Hamann, Kenneth I. Joy, Eric Brugger, Mark Duchaineau, March 2000
Ask Jack
By Jack Wilson, March 2000
Introduction
By Kevin Fu, September 1999
Objective viewpoint
By George Crawford, September 1999
Choosing a Ph.D. program in computer science
By Rachel Pottinger, September 1999
Linux DSP shell
By Michael Stricklen, Bob Cummings, Brandon Bonner, September 1999
Introduction to Linux networking and security
By Wei-Mei Shyr, Brian Borowski, September 1999
Parallel computing with Linux
By Forrest Hoffman, William Hargrove, September 1999
The Texas Tech tornado cluster
By Per Andersen, September 1999
Introduction
By Alessio Lomusico, June 1999
Where do intelligent agents come from?
By Cristobal Baray, Kyle Wagner, June 1999
Protecting the integrity of agents
By Michael J. Grimley, Brian D. Monroe, June 1999
Towards a standardization of multi-agent system framework
By Roberto A. Flores-Mendez, June 1999
Web hunting
By G. Michael Youngblood, June 1999
Re-configurable computing
By Richard Swan, Anthony Wyatt, Richard Cant, Caroline Langensiepen, April 1999
The processor-memory bottleneck
The rate of improvement in microprocessor speed exceeds the rate of improvement in DRAM (Dynamic Random Access Memory) speed. So although the disparity between processor and memory speed is already an issue, downstream someplace it will be a much bigger one. Hence computer designers are faced with an increasing Processor - Memory Performance Gap [1], which now is the primary obstacle to improved computer system performance. This article examines this problem as well as its various solutions.
By Nihar R. Mahapatra, Balakrishna Venkatrao, April 1999
Introduction
By Scott Lewandowski, March 1999
Objective viewpoint
By George Crawford, March 1999
Making a careers presentation
By Jack Wilson, March 1999
PiSMA
By Dimitris Lioupis, Andreas Pipis, Maria Smirli, Michael Stefanidakis, March 1999
Architectures and compilers to support reconfigurable computing
By João M. P. Cardoso, Mário P. Vestístias, March 1999