6340669
Phylospaces: reconstructing evolutionary trees in tuple space
Phylospaces is a novel framework for reconstructing evolutionary trees in tuple space, a distributed shared memory that permits processes to communicate and coordinate with each other. Our choice of tuple space as a concurrency model is somewhat unusual, given the prominence and success of pure message passing models, such as MPI. We use phylospaces to devise cooperative Rec-I-DCM3, a population-based strategy for navigating tree space. Cooperative Rec-I-DCM3 is based on Rec-I-DCM3, the fastest sequential algorithm under maximum parsimony. We compare the performance of the algorithms on two datasets consisting of 2,000 and 7,769 taxa, respectively. Our results demonstrate that cooperative Rec-I-DCM3 outperforms its sequential counterpart by at least an order of magnitude
7755497
Teaching Java Concurrency to CS vs IT Students: A Matter of Emphasis
A number of colleges and universities have recently added new degree programs in Information Technology (IT), or added IT components to existing Computer Science (CS) programs. Java language and technology are almost inescapable elements of both CS and IT programs. One of Java's more advanced features, languagelevel support for concurrency in the form of explicit multithreading, is important to both CS and IT students, but for different reasons. Teaching Java concurrency to CS and IT students, therefore, presents different challenges and requires emphasizing the topic in different ways. We discuss these issues, and present our experiences from CS and IT classes taught recently, in which Java concurrency was a topic.
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.
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.
5238518
Evolving video skims into useful multimedia abstractions
This paper reports two studies that measured the effects of different “video skim” techniques on comprehension, navigation, and user satisfaction. Video skims are compact, content-rich abstractions of longer videos, condensations that preserve frame rate while greatly reducing viewing time. Their characteristics depend on the image- and audio-processing techniques used to create them. Results from the initial study helped refine video skims, which were then reassessed in the second experiment. Significant benefits were found for skims built from audio sequences meeting certain criteria.
14666057
Video skimming and characterization through the combination of image and language understanding techniques
Digital video is rapidly becoming important for education, entertainment, and a host of multimedia applications. With the size of the video collections growing to thousands of hours, technology is needed to effectively browse segments in a short time without losing the content of the video. We propose a method to extract the significant audio and video information and create a "skim" video which represents a very short synopsis of the original. The goal of this work is to show the utility of integrating language and image understanding techniques for video skimming by extraction of significant information, such as specific objects, audio keywords and relevant video structure. The resulting skim video is much shorter, where compaction is as high as 20:1, and yet retains the essential content of the original segment.
7156330
Balancing FPGA Resource Utilities
Balancing the use of FGPA resources such as FPGA slices, block RAMs, and block multipliers is desirable in many FPGA applications. This task can be carried out manually by experienced hardware designers with the use of hardware description languages, such as Verilog and VHDL. However, many users of reconfigurable computers are software developers who depend on hardware synthesis tools or even high-level synthesis tools to deal with the details beneath the application logic. In this paper, a motivating example of balancing FPGA resource utilities is given first. A module selection optimization problem is then formulated, in which, balancing FPGA resource utilities is treated as a constraint, so that the solution to the module selection problem is the balanced use of the FPGA resources. Several variations of the problem formulation are discussed. A naive algorithm and an efficient greedy algorithm to solve the problem are provided and compared. Some experimental results are also presented.
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.