9375021
Dynamic Data Grid Replication Strategy Based on Internet Hierarchy
In data grid, large quantity of data files is produced and data replication is applied to reduce data access time. Efficiently utilizing grid resources becomes important research issue since available resources in grid are limited while large number of workloads and large size of data files are produced. Dynamic replication in data grid aims to reduce data access time and to utilize network and storage resources efficiently. This paper proposes a novel dynamic replication strategy, called BHR, which reduces data access time by avoiding network congestions in a data grid network. With BHR strategy, we can take benefits from ‘network-level locality’ which represents that required file is located in the site which has broad bandwidth to the site of job execution. We evaluate BHR strategy by implementing it in an OptorSim, a data grid simulator initially developed by European Data Grid Projects. The simulation results show that BHR strategy can outperform other optimization techniques in terms of data access time when hierarchy of bandwidth appears in Internet. BHR extends current site-level replica optimization study to the network-level.
816246
Alternative Software Stacks for OGSA-based Grids
The Open Grid Services Architecture (OGSA) has been a major step forward for Grid Computing, but its de facto reliance on the Web Services Resource Framework (WSRF) and WS-Notification have left some in the community questioning if the Grid software and protocols have become too complex. In this paper, we consider the feasibility of an "alternative" software stack, based on WS-Transfer and WS-Eventing. We compare and evaluate WSRF/WS-Notification vs. WS-Transfer/WSEventing, first via a "hello world" service and then via a more complete Grid scenario for remote execution called "Grid-in-a-Box". By qualitatively and quantitatively evaluating each approach, we find that while subtle differences exist (e.g., the naming of resources, the creation of resources), the stacks are overwhelmingly equivalent in their functionality and implied performance. Overall, this paper uniquely shows that there could be alternative software stacks for OGSA-based Grids.
3150650
Fault-Tolerant All-to-All Broadcasting in Hypercubes
439941
Iterative exploration, design and evaluation of support for query reformulation in interactive information retrieval
We report on the progressive investigation of techniques for supporting interactive query reformulation in the TREC Interactive Track. Two major issues were explored over four successive years: methods of term suggestion; and, interface design to support different system functionalities. Each year's results led to the following year's investigation, with respect to both of these issues. This paper presents first the general motivation for the entire series of studies; then an overview of each year's investigation, its results, and how they influenced the next year's investigation. We discuss what has been learned through this series of investigations about effective term suggestion, usable and useful interface design, and the relationships between these two in support of the TREC Interactive Track task. We conclude with comments about the general methodology employed over this series of studies, and its relevance to the development and evaluation of interactive information retrieval systems.
17481727
Strain analysis and visualization: left ventricle of a heart
Abstract Clinical utility of computational models is crucial in the applications of medical data visualization. Previously we have developed a new class of volumetric models whose parameters are functions in conjunction with physically based deformable modeling framework, and have applied the technique to estimate the left ventricular (LV) wall motion. We have successfully showed that the model parameter functions characterize the LV motion of normal and abnormal states and that no further non-trivial post-processing is required for anatomically meaningful interpretation. In an effort to evaluate the LV model, this paper presents a method and results from a strain analysis based on the nodal displacements of the deformable LV model. Furthermore, in order to visualize the local quantities on the volumetric model for an effective analysis, we also developed a methodology to assist in assessing the cardiac function utilizing principal strains, Von-Mises’ yield criteria, and a smoothing filter. Each strain tensor component was in the range of values observed in other reported studies. The application of a smoothing filter on the model improved in visualizing the overall trend of each strain variation. With our platform for a comprehensive strain analysis, we have augmented a clinical utility to the deformable models with parameter functions.
20757485
Rigorous Modeling of Disk Performance for Real-Time Applications
Performance modeling of magnetic disks allows the prediction of the disk service time which is useful for on-line decision support for soft real-time applications. In this paper, we propose a new performance model of disk access time to estimate the bounded disk service time. Our proposed model focuses on modeling the head positioning time to fully utilize the disk I/O bandwidth by exploiting the geometric layout of the disk. The experimental results show that our proposed model can estimate the disk service time with less than 10% error on average.
404376
Power-aware deterministic block allocation for low-power way-selective cache structure
This paper proposes a power-aware cache block allocation algorithm for the way-selective set-associative cache on embedded systems to reduce energy consumption without additional delay or performance degradation. For this goal, way selection logic and specialized replacement policy are designed to enable only one way of set-associative cache as in the direct-mapped cache. Overall cache access time becomes almost the same as that of a conventional set associative cache with accessing additional way selection logic. Because data array can be accessed without waiting for tag comparison, multiplexer delay can be removed totally. The simulation result shows that the proposed architecture can reduce a per access power consumption by 59% over conventional set-associative caches with average 0.06% of negligible performance loss.