• Journal of KIISE:Computer Systems and Theory
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• v.30 no.3_4
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• pp.117-129
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• 2003

In this paper, we propose advanced parallel join algorithm to efficiently process join operation on hypercube systems. This algorithm uses a broadcasting method in processing relation R which is compatible with hypercube structure. Hence, we can present optimized parallel join algorithm for that hypercube structure. The proposed algorithm has a complete solution of two essential problems - load balancing problem and data skew problem - in parallelization of join operation. In order to solve these problems, we made good use of the characteristics of clustering effect in the algorithm. As a result of this, performance is improved on the whole system than existing algorithms. Moreover. new algorithm has an advantage that can implement non-equijoin operation easily which is difficult to be implemented in hash based algorithm. Finally, according to the cost model analysis. this algorithm showed better performance than existing parallel join algorithms.

• Convergence Security Journal
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• v.9 no.2
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• pp.1-6
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• 2009

Most diagnosis algorithms have been done using the characteristic of t-diagnosable system based on PMC model. But as parallel systems grow fast, more faulty units occur in the system. Previous researches are done on the assumption of small number of faulty units in the system. There have been little studies on the system where number of faulty units exceed t. In this study, we assume the number of faulty units exceed t and there exist small number of nodes where the correctness of diagnosis can't be decided, then we propose an algorithm which increase the maximum number of faulty units in diagnosis system.

• The Journal of the Korea Contents Association
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• v.2 no.2
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• pp.103-111
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• 2002

In parallel application programs with a localized communication, even if the MINs have lour diameters, overall system performance degrades when compared to the hypercube and tree structure. The reason is that it is impossible for MINs to provide some mechanisms for clustering to exploit the locality of reference. However proposed MIN can be constructed suitable for localized communication by providing the shortcut path and multiple paths inside the processor-memory duster which has frequent data communications. Therefore proposed MIN achieves enhanced performance in parallel application program with a localized communication.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.5
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• pp.1180-1192
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• 1996

On demand of many users, basic networks of a parallel computer system are required to have a property that can embed various topologies. Bisectional interconnection network is known to satisfy this property, and it can embed various topologies optimally. Nowadays one is very interested in the hypercube as a message pssing multicomputer system, so it is very important to implement a hypercube in bisectional network. In this paper, a hypercube is implemented in a versatile bisecional netork, and its routing and broadcasting algorithm are proposed. Conventional bisectional network can accomodata linear array, complete binary tree and mesh structure as its topology. Now hypercube is implemented to be utilized as a general purpose supercomputercommunication architecture. The proposed routing and broadcasting algorithm embedded in bisectional network are general purpose algorithms which satisfy property of conventional hypercube.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.5C
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• pp.483-489
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• 2006

Somani and Peleg proposed t/k-diagnosable system to diagonse more faults than t(dimension) by allowing upper bounded few number of units to be diagnosed incorrectly. Kranakis and Pelc showed that their adaptive diagnosis algorithm was more efficient than that of any previous ones, assuming that the number of faults does not exceed the hypercube dimension. We propose an adaptive diagnosis algorithm using the idea of t/k-diagnosable system on the basis of that of Kranakis and Pelc's. When the number of faults exceeds t, we allow a fault(k=1, 2, 3) to be diagnosed incorrectly. Based on this idea, we find that the performance of the proposed algorithm is nearly as efficient as any previously known strategies and detect above about double faults.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.1
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• pp.87-99
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• 1998

In the multicasting communications, the quality of service is not guaranteed occasionally, according to the shortage of resources, because all resources such as communication buffer, processing power for the packet multiplication, and bandwidth, should be shared among each members. This problem can be solved through the hierarchical multicaster construction mechanism which guarantees that all multicaster can be operated within the required performance. This paper proposes the architecture of multipoint communication server based on hypercube type massively parallel computer. Through the simulation, it is verified that the traffic of links between each node of hypercube computer is under the some bandwidth. So, it is certified that the hypercube computer is suitable for the multicast communication servers supporting the various groups.

• The Transactions of the Korea Information Processing Society
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• v.3 no.4
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• pp.766-780
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• 1996

This paper presents a mapping scheme for parallel processing using an accurate characterization of the communication overhead. A set of objective functions is formulated to evaluate the optimality of mapping a problem graph into a system graph. One of them is especially suitable for real-time applications of parallel processing. These objective functions are different from the conventional objective functions in that the edges in the problem graph are weighted and the actual distance rather than the nominal distance for the edges in the system graph is employed. This facilitates a more accurate qualification of the communication overhead. An efficient mapping scheme has been developed for the objective functions, where two levels of assignment optimization procedures are employed: initial assignment and pairwise exchange. The mapping scheme has been tested using the hypercube as a system graph.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.12
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• pp.1902-1918
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• 1993

Parallel architecture based on the von Neumann computation model has a limitation as a massively parallel architecture due to its inherent drawback of architectural features. The data-flow model of computation has a high programmability in software perspective and high scalability in hardware perspective. However, the practical programming and experimentaion of date-flow architectures are hardly available due to the absence of practical data-flow, we present a programming environment for performing the data-flow computation on conventional parallel machines in general, loosely compled multiprocessor system in particular. We build an emulator for tagged token data-flow architecture on the iPSC/2 hypercube, a loosely coupled multiprocessor system. The emulator is a shallow layer of software executing on an iPSC/2 system, and thus makes the iPSC/2 system work as a data-flow architecture from the programmer`s viewpoint. We implement various numerical and non-numerical algorithm in a data-flow assembler language, and then compare the performance of the program with those of the versions of conventional C language, Consequently, We verify the effectiveness of this programming environment based on the emulator in experimenting the data-flow computation on a conventional parallel machine.

• The Transactions of the Korea Information Processing Society
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• v.3 no.1
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• pp.55-62
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• 1996

MRNS network is a general algebraic structure of Hypercube network which has recently drawn considerable attention to supercomputing and message-passing communication. In this paper, we investigate the routing of a message in an n- dimensional MRNS network that is a key to the performance of this network. On the n-dimensional MRNS network we would like to transmit packets from a source node to a destination node simultaneously along a fixed number of paths, where the superscript packet will traverse along the superscript path. In order for all packets to arrive at the destination node quickly and securely, the ith path must be node-disjoint from all other paths. By investigating the conditions of node-disjoint paths, we will employ the special matrices called as the Hamiltonian Circuit Latin Square(HCLS) described in 〔1〕to construct a set of node-disjoint paths and suggest a linear-time parallel routing algorithm for the MRNS network.

• Journal of KIISE:Computer Systems and Theory
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• v.37 no.2
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• pp.61-65
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• 2010

The twisted cube has received great attention because it has several superior properties to the hypercube that is widely known as a versatile parallel processing system. In this paper, we show that node-disjoint $2^{n-1}$ meshes of size $2^n{\times}2^m$ can be embedded into a twisted cube with dilation 1 where $1{\leq}n{\leq}m$. The expansion is 1 for even m and 2 for odd m.