41968338
Group-Based Scheduling Scheme for Result Checking in Global Computing Systems
This paper considers the problem of correctness to fault-tolerance in global computing systems. Global computing system has been shown to be exposed to intentional attacks, where authentication is not relevant, network security techniques are insufficient. To guarantee correctness for computation, fault-tolerance schemes have been used to majority voting and spot-checking but these schemes intend to high computation delay because are not applied scheduling scheme for result checking. In this paper, we propose a new technique called GBSS(Group-Based Scheduling Scheme) which guarantee correctness and reduce computation delay by using fault-tolerant scheduling scheme to the result checking. Additionally, simulation results show increased usable rate of the CPU and increased performance of the system.
24012185
Dynamic Scheduling Mechanism for Result Certification in Peer to Peer Grid Computing
In a peer to peer grid computing environment, volunteers have heterogeneous properties and dynamically join and leave during execution. Therefore, it is essential to adapt to an unstable and widely distributed environment. However, existing scheduling and result certification mechanisms do not adapt to such a dynamic environment. As a result, they undergo high overhead, performance degradation, and scalability problems. 
 
To solve the problems, we propose a new scheduling mechanism for result certification. The proposed mechanism applies different scheduling and result certification algorithms to different volunteer groups that are classified on the basis of their properties such as volunteering service time, availability, and credibility. It also exploits mobile agents in a distributed way in order to adapt to a dynamic peer to peer grid computing environment.
9484226
Group-based dynamic computational replication mechanism in peer-to-peer grid computing
A peer-to-peer grid computing is complicated by heterogeneous capabilities, failures, volatility, and lack of trust because it is based on desktop computers at the edge of the Internet. In order to improve the reliability of computation and gain better performance, a replication mechanism must adapt to these distinct features. In other words, it is required to classify volunteers into groups that have similar properties and then dynamically apply different replication algorithms to each group. However, existing mechanisms do not provide such a replication mechanism on a per group basis. As a result, they cause a high overhead and poor performance. To solve the problems, we propose a new group-based computational replication mechanism to adapt to an unstable, untrusted, dynamic peer-to-peer grid computing environment. Our mechanism can reduce the number of redundancy and therefore complete many tasks by adaptively replicating computations on the basis of the properties of volunteer group such as availability, credibility, and volunteering service time
46325531
A utility range-based interactive group support system for multiattribute decision making
Abstract This research suggests an interactive procedure for solving a multiattribute group decision problem using a range-typed utility information, and develops an interactive group support system (RINGS) to implement some capabilities of the procedure. It is often difficult for group members to articulate their preferences with cardinal values, instead they prefer to give incomplete information only. Utility ranges are obtained by solving linear programming problems with incompletely specified information. RINGS finds out conflicting opinions among group members, compares each member's preferences with the others’, and suggests a direction for consensus seeking. The procedure of RINGS utilizes range-typed visual information, which helps the group reach a consensus. RINGS has several facilities like graphic user interface, model base, and database, so the total time to reach a group consensus is reduced. The evaluation of information systems is illustrated as a demonstration of some capabilities of RINGS. Scope and purpose This paper deals with the multiple attribute decision-making problem using a separable linear programming technique when group decision makers give only their incomplete information about the attribute weight and alternative value. The utility range for individual decision maker is calculated from each decision maker's incomplete information, and the utility range for group decision makers is obtained from those of individual decision makers. An interactive procedure for establishing a group's pairwise dominance relations with a group's utility range is described, and an interactive group support system (RINGS) is developed to implement the procedure. A case study about the evaluation of information systems is illustrated as a demonstration of some capabilities of RINGS.
14838232
Towards Semantic Goal-Directed Forward Reasoning in Resolution
Semantic goal-directed forward reasoning is a three stage procedure. In the first stage a reference set of models is generated from the negated theorem. In the second stage the assumption clause set is refined to a set which has an as small set of models as possible in common with the negated theorem with respect to the reference set of models. In the last stage a refutation is generated in the space consisting of the original problem along with the refined assumption. In order to form a refined assumption, unlike traditional approaches like set of support, only clauses from assumptions are resolved with each other.
47222760
A Simple Algorithm for Homeomorphic Surface Reconstruction
The problem of computing a piecewise linear approximation to a surface from a set of sample points is important in solid modeling, computer graphics and computer vision. A recent algorithm1 using the Voronoi diagram of the sample points gave a guarantee on the distance of the output surface from the original sampled surface assuming that the sample was sufficiently dense. We give a similar algorithm, simplifying the computation and the proof of the geometric guarantee. In addition, we guarantee that our output surface is homeomorphic to the original surface; to our knowledge this is the first such topological guarantee for this problem.
5975093
Multi-chain prefetching: effective exploitation of inter-chain memory parallelism for pointer-chasing codes
Presents multi-chain prefetching, a technique that utilizes offline analysis and a hardware prefetch engine to prefetch multiple independent pointer chains simultaneously, thus exploiting inter-chain memory parallelism for the purpose of memory latency tolerance. This paper makes three contributions. First, we introduce a scheduling algorithm that identifies independent pointer chains in pointer-chasing codes and computes a prefetch schedule that overlaps serialized cache misses across separate chains. Our analysis focuses an static traversals. We also propose using speculation to identify independent pointer chains in dynamic traversals. Second, we present the design of a prefetch engine that traverses pointer-based data structures and overlaps multiple pointer chains according to our scheduling algorithm. Finally, we conduct an experimental evaluation of multi-chain prefetching and compare its performance against two existing techniques: jump pointer prefetching and prefetch arrays. Our results show that multi-chain prefetching improves the execution time by 40% across six pointer-chasing kernels from the Olden benchmark suite and by 8% across four SPECInt CPU2000 benchmarks. Multi-chain prefetching also outperforms jump pointer prefetching and prefetch arrays by 28% on Olden, and by 12% on SPECInt. Furthermore, speculation can enable multi-chain prefetching for some dynamic traversal codes, but our technique loses its effectiveness when the pointer-chain traversal order is unpredictable. Finally, we also show that combining multi-chain prefetching with prefetch arrays can potentially provide higher performance than either technique alone.
2658837
A general framework for prefetch scheduling in linked data structures and its application to multi-chain prefetching
Pointer-chasing applications tend to traverse composite data structures consisting of multiple independent pointer chains. While the traversal of any single pointer chain leads to the serialization of memory operations, the traversal of independent pointer chains provides a source of memory parallelism. This article investigates exploiting such interchain memory parallelism for the purpose of memory latency tolerance, using a technique called multi--chain prefetching. Previous works [Roth et al. 1998;Roth and Sohi 1999] have proposed prefetching simple pointer-based structures in a multi--chain fashion. However, our work enables multi--chain prefetching for arbitrary data structures composed of lists, trees, and arrays.This article makes five contributions in the context of multi--chain prefetching. First, we introduce a framework for compactly describing linked data structure (LDS) traversals, providing the data layout and traversal code work information necessary for prefetching. Second, we present an off-line scheduling algorithm for computing a prefetch schedule from the LDS descriptors that overlaps serialized cache misses across separate pointer-chain traversals. Our analysis focuses on static traversals. We also propose using speculation to identify independent pointer chains in dynamic traversals. Third, we propose a hardware prefetch engine that traverses pointer-based data structures and overlaps multiple pointer chains according to the computed prefetch schedule. Fourth, we present a compiler that extracts LDS descriptors via static analysis of the application source code, thus automating multi--chain prefetching. Finally, we conduct an experimental evaluation of compiler-instrumented multi--chain prefetching and compare it against jump pointer prefetching [Luk and Mowry 1996], prefetch arrays [Karlsson et al. 2000], and predictor-directed stream buffers (PSB) [Sherwood et al. 2000].Our results show compiler-instrumented multi--chain prefetching improves execution time by 40% across six pointer-chasing kernels from the Olden benchmark suite [Rogers et al. 1995], and by 3% across four SPECint2000 benchmarks. Compared to jump pointer prefetching and prefetch arrays, multi--chain prefetching achieves 34% and 11% higher performance for the selected Olden and SPECint2000 benchmarks, respectively. Compared to PSB, multi--chain prefetching achieves 27% higher performance for the selected Olden benchmarks, but PSB outperforms multi--chain prefetching by 0.2% for the selected SPECint2000 benchmarks. An ideal PSB with an infinite Markov predictor achieves comparable performance to multi--chain prefetching, coming within 6% across all benchmarks. Finally, speculation can enable multi--chain prefetching for some dynamic traversal codes, but our technique loses its effectiveness when the pointer-chain traversal order is highly dynamic.