7182268
Accelerating scientific applications with the SRC-6 reconfigurable computer: methodologies and analysis
Reconfigurable computing offers the promise of performing computations in hardware to increase performance and efficiency while retaining much of the flexibility of a software solution. Recently, the capacities of reconfigurable computing devices, like field programmable gate arrays, have risen to levels that make it possible to execute 64b floating-point operations. SRC Computers has designed the SRC-6 MAPstation to blend the benefits of commodity processors with the benefits of reconfigurable computing. In this paper, we describe our effort to accelerate the performance of several scientific applications on the SRC-6. We describe our methodology, analysis, and results. Our early evaluation demonstrates that the SRC-6 provides a unique software stack that is applicable to many scientific solutions and our experiments reveal the performance benefits of the system.
52872904
Simulative analysis of dynamic scheduling heuristics for reconfigurable computing of parallel applications
The demand for processing power has been ever increasing with the growth of high-performance computing (HPC) applications and so have the constraints restricting the solutions to such requirements. High-performance distributed and parallel computing and custom-built, hardware-based computing have attempted to address this problem with some success but at a substantial cost. Recently, systems augmented with Field-Programmable Gate Arrays (FPGAs) offering a fusion of traditional parallel and distributed machines with customizable and dynamically reconfigurable hardware have emerged as a cost-effective alternative to traditional systems. However, providing a robust runtime environment for such systems to which HPC users have become accustomed has been fraught with numerous challenges. Dynamic scheduling of large-scale HPC applications in such parallel reconfigurable computing (RC) environments is one such challenge and has not been sufficiently studied to our knowledge. In this paper, we simulatively analyze the performance of several common HPC scheduling heuristics that can be used by an automated job management service to schedule application tasks on a parallel RC system. We also present a performance prediction model which the scheduling heuristics employ to schedule several common HPC applications on a collection of typical FPGA processing platforms.
6308382
Cooperative Rec-I-DCM3: A Population-Based Approach for Reconstructing Phylogenies
In this paper, we study the use of cooperation as a technique for designing faster algorithms for reconstructing phylogenetic trees. Our focus is on the use of cooperation to reconstruct trees based on maximum parsimony. Our baseline algorithm is Rec-I-DCM3, the best-performing MP algorithm known-to-date. Our results demonstrate that cooperation does improve the performance of the baseline algorithm by at least an order of magnitude in terms of running time. The use of cooperation also established a new best known score on one of our datasets.
5888435
Visualization components for persistent conversations
An appropriately designed interface to persistent, threaded conversations could reinforce socially beneficial behavior by prominently featuring how frequently and to what degree each user exhibits such behaviors. Based on the data generated by the Netscan data-mining project [9], we have developed a set of tools for illustrating the structure of discussion threads like those found in Usenet newsgroups and the patterns of participation within the discussions. We describe the benefits and challenges of integrating these tools into a multi-faceted dashboard for navigating and reading discussions in social cyberspaces like Usenet and related interaction media. Visualizations of the structure of online discussions have applications for research into the sociology of online groups as well as possible interface designs for their members.
1384762
The Early Word Catches the Weights
The strong correlation between the frequency of words and their naming latency has been well documented. However, as early as 1973, the Age of Acquisition (AoA) of a word was alleged to be the actual variable of interest, but these studies seem to have been ignored in most of the literature. Recently, there has been a resurgence of interest in AoA. While some studies have shown that frequency has no effect when AoA is controlled for, more recent studies have found independent contributions of frequency and AoA. Connectionist models have repeatedly shown strong effects of frequency, but little attention has been paid to whether they can also show AoA effects. Indeed, several researchers have explicitly claimed that they cannot show AoA effects. In this work, we explore these claims using a simple feed forward neural network. We find a significant contribution of AoA to naming latency, as well as conditions under which frequency provides an independent contribution.
5639011
A Characterization of Lazy and Eager Semantic Solutions to the Linda Predicates Ambiguity Problem
The problems associated with Linda predicate operations inp() and rdp() are well known but not always well understood. One problem, from a purely academic standpoint, is that of semantic ambiguity in the case of failure. Despite this problem, commercial tuple space implementations all provide some version of the Linda predicate operations, and thus, problems concerning safety and liveness arise. Solutions to address these problems range from proposing extensions to an existing model of computation (CSP) to proposing alternative definitions for the Linda predicate operations themselves. While these solutions may at first appear unrelated, it is possible to relate these two disparate approaches in the context of lazy and eager semantics. The benefits of this characterization include a clearer understanding of the Linda predicates ambiguity problem, two respective solutions to this problem, and the importance of considering both lazy and eager semantic perspectives as techniques for problem solving in parallel and distributed systems.
26831752
Incrementally visualising criminal networks
Understanding the information gathered thus far in a criminal investigation is of great importance, particularly in terms of guiding its future course. Since the late 1980's the use of software tools to provide visualisations of this information has become increasingly common. The objective of such tools is to provide, in a readily comprehensible way, the social network of all the people involved. This may include the victims, suspects, witnesses, acquaintances and locations of interest in the investigation such as workplaces or nightclubs. Such diagrammatic representations often provide the focus for discussion among the investigating team and are incrementally added to as new facts are discovered. In this paper we present a brief overview of this important subject area and discuss how such software products could be further enhanced. We also present an example that illustrates the basic principles using a demonstrator we developed.