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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The KIPS Transactions:PartA
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Korea Information Processing Society
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Volume & Issues
Volume 8A, Issue 4 - Dec 2001
Volume 8A, Issue 3 - Sep 2001
Volume 8A, Issue 2 - Jun 2001
Volume 8A, Issue 1 - Mar 2001
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A Reconfigurable Memory Allocation Model for Real-Time Linux System
Sihm, Jae-Hong ; Jung, Suk-Yong ; Kang, Bong-Jik ; Choi, Kyung-Hee ; Jung, Gi-Hyun ;
The KIPS Transactions:PartA, volume 8A, issue 3, 2001, Pages 189~200
This paper proposes a memory allocation model for Real-Time Linux. The proposed model allows users to create several continuous memory regions in an application, to specify an appropriate region allocation policy for each memory region, and to request memory blocks from a necessary memory region. Instead of using single memory management module in order to support the proposed model, we adopt two-layered structure that is consisted of region allocators implementing allocation policies and a region manager controlling regions and region allocator modules. This structure separates allocation policy from allocation mechanism, thus allows system developers to implement same allocation policy using different algorithms in case of need. IN addition, it enables them to implement new allocation policy using different algorithms in case of need. In addition, it enables them to implement new allocation policy easily as long as they preserver predefined internal interfaces, to add the implemented policy into the system, and to remove unnecessary allocation policies from the system, Because the proposed model provides various allocation policies implemented previously, system builders can also reconfigure the system by just selecting most appropriate policies for a specific application without implementing these policies from scratch.
Analysis of Web Server Referencing Characteristics and performance Improvement of Web Server
Ahn, Hyo-Beom ; Cho, Kyung-San ;
The KIPS Transactions:PartA, volume 8A, issue 3, 2001, Pages 201~208
Explosive growth of the Web and the non-uniform characteristics of client requests result in the performance degradation of Web servers, and server cache has been recognized as the solution. We analyzed Web server accessing characteristics-repetition, size, and locality of access. Based on the result, we analyzed the cache removal policies and proposed a prefetch strategy to improve the hit ratio of server caches. In addition, through the trace-driven simulation based on the traces from real Web sites, we showed the performance improvement by our proposal.
A study on the effectively optimized algorithm for an incremental attribute grammar
Jang, Jae-Chun ; Ahn, Heui-Hak ;
The KIPS Transactions:PartA, volume 8A, issue 3, 2001, Pages 209~216
The effective way to apply incremental attribute grammar to a complex language process is the use of optimized algorithm. In optimized algorithm for incremental attribute grammar, the new input attribute tree should be exactly compared with the previous input attribute tree, in order to determine which subtrees from the old should be used in constructing the new one. In this paper the new optimized algorithm was reconstructed by analyzing the algorithm suggested by Carle and Pollock, and a generation process of new attribute tree d’copy was added. Through the performance evaluation for the suggested matching algorithm, the run time is approximately improved by 19.5%, compared to the result of existing algorithm.
Integrated Stochastic Admission Control Policy in Clustered Continuous Media Storage Server
Kim, Yeong-Ju ; No, Yeong-Uk ;
The KIPS Transactions:PartA, volume 8A, issue 3, 2001, Pages 217~226
In this paper, for continuous media access operations performed by Clustered Continuous Media Storage Server (CCMSS) system, we present the analytical model based on the open queueing network, which considers simultaneously two critical delay factors, the disk I/O and the internal network, in the CCMSS system. And we derive by using the analytical model the stochastic model for the total service delay time in the system. Next, we propose the integrated stochastic admission control model for the CCMSS system, which estimate the maximum number of admittable service requests at the allowable service failure rate by using the derived stochastic model and apply the derived number of requests in the admission control operation. For the performance evaluation of the proposed model, we evaluated the deadline miss rates by means of the previous stochastic model considering only the disk I/O and the propose stochastic model considering the disk I/O and the internal network, and compared the values with the results obtained from the simulation under the real cluster-based distributed media server environment. The evaluation showed that the proposed admission control policy reflects more precisely the delay factors in the CCMSS system.
A Scalable Parallel Preconditioner on the CRAY-T3E for Large Nonsymmetric Spares Linear Systems
Ma, Sang-Baek ;
The KIPS Transactions:PartA, volume 8A, issue 3, 2001, Pages 227~234
In this paper we propose a block-type parallel preconditioner for solving large sparse nonsymmetric linear systems, which we expect to be scalable. It is Multi-Color Block SOR preconditioner, combined with direct sparse matrix solver. For the Laplacian matrix the SOR method is known to have a nondeteriorating rate of convergence when used with Multi-Color ordering. Since most of the time is spent on the diagonal inversion, which is done on each processor, we expect it to be a good scalable preconditioner. We compared it with four other preconditioners, which are ILU(0)-wavefront ordering, ILU(0)-Multi-Color ordering, SPAI(SParse Approximate Inverse), and SSOR preconditiner. Experiments were conducted for the Finite Difference discretizations of two problems with various meshsizes varying up to
. CRAY-T3E with 128 nodes was used. MPI library was used for interprocess communications, The results show that Multi-Color Block SOR is scalabl and gives the best performances.
InterCom : Design and Implementation of an Agent-based Internet Computing Environment
Kim, Myung-Ho ; Park, Kweon ;
The KIPS Transactions:PartA, volume 8A, issue 3, 2001, Pages 235~244
Development of network and computer technology results in many studies to use physically distributed computers as a single resource. Generally, these studies have focused on developing environments based on message passing. These environments are mainly used to solve problems for scientific computation and process in parallel suing inside parallelism of the given problems. Therefore, these environments provide high parallelism generally, while it is difficult to program and use as well as it is required to have user accounts in the distributed computers. If a given problem is divided into completely independent subproblems, more efficient environment can be provided. We can find these problems in bio-informatics, 3D animatin, graphics, and etc., so the development of new environment for these problems can be considered to be very important. Therefore, we suggest new environment called InterCom based on a proxy computing, which can solve these problems efficiently, and explain the implementation of this environment. This environment consists of agent, server, and client. Merits of this environment are easy programing, no need of user accounts in the distributed computers, and easiness by compiling distributed code automatically.
Dynamic Task Scheduling for 3D Torus Multicomputer Systems
Choo, Hyun-Seung ; Youn, Hee-Yong ; Park, Gyung-Leen ;
The KIPS Transactions:PartA, volume 8A, issue 3, 2001, Pages 245~252
Multicomputer systems achieve high performance by utilizing a number of computing nodes. Multidimensional meshes have become popular as multicomputer architectures due to their simplicity and efficiency. In this paper we propose an efficient processor allocation scheme for 3D torus based on first-fit approach. The scheme minimizes the allocation time by effectively manipulating the 3D information an 2D information using CST (Coverage Status Table). Comprehensive computer simulation reveals that the allocation time of the proposed scheme is always smaller than the earlier scheme based on best-fit approach, while allowing comparable processor utilization. The difference gets more significant as the input load increases. To investigate the performance of the proposed scheme with different scheduling environment, non-FCFs scheduling policy along with the typical FCFS policy is also studied.
Detecting the First Race in OpenMP Program with Nested Parallelism
Chon, Byoung-Gyu ; Woo, Jong-Jung ; Jun, Yong-Kee ;
The KIPS Transactions:PartA, volume 8A, issue 3, 2001, Pages 253~260
It is important to detect races for debugging shared-memoy parallel programs, because the races cause unintended nondeterministic program execution. Previous on-the-fly techniques to detect races can not guarantee the first race detection in nested parallel programs. Detecting the first race is important for debugging parallel programs, since the removal of the first race may make the next occurred races disappear. In this paper, we presents an on-the-fly detection technique to detect all of the first races through the reexecution of the debugged programs. We assume that the debugged parallel program may have one-way nested parallel programs. The number of reexecution is at the least the nesting depth of the program in the worst case. The space complexity is O(VT) and the time complexity to detect race in each access of access history is O(T), where V is number of shared variables and T is the maximum parallelism of the program. This efficiency of our technique in each execution is the same with the previous on-the-fly detection techniques. Therefore, this technique makes debugging parallel programs more effective and practical.
Dynamic Multi-distributed Web Cluster Group Model for Availability of Web Business
Lee, Gi-Jun ; Park, Gyeong-U ; Jeong, Chae-Yeong ;
The KIPS Transactions:PartA, volume 8A, issue 3, 2001, Pages 261~268
With the rapid growth of the Internet, various web-based businesses are creating a new environment in an imaginary space. However, this expanding Internet and user increase cause an overflow of transmission and numerous subordinate problems. To solve these problems, a parallel cluster system is produced using different methods. This thesis recommends a multi0distribution cluster group. It constructs a MPP dynamic distribution sub-cluster group using numerous low-priced and low-speed systems. This constructed sub-cluster group is then connected with a singular virtual IP to finally serve the needs of clients (users). This multi-distribution cluster group consists of an upper structure based on LVS and a dynamic serve cluster group centered around an SC-server. It conducts the workloads required from users in a parallel process. In addition to the web service, this multi-distribution cluster group can efficiently be utilized for the calculations which require database controls and a great number of parallel calculations as well as additional controls with result from the congestion of service.
A Study on the PCB automatic routing by shape based method using the auction algorithm
Woo, Kyong-Hwan ; Lee, Cheon-Hee ;
The KIPS Transactions:PartA, volume 8A, issue 3, 2001, Pages 269~278
Routing region modeling method of auto_routing systems are use the grid and the non-grid type. Though grid type has a few electrical and physical element on PCB, grid type has disadvantage which decrease the auto-routing speed dur to constraint with board and gird size. Thus it increase the memory capacity, Non-grid type(Shape baed type) use the region processing type, so it has 44.2% memory decrease effect than grid type in routing region. Thus, via number has 55% decrease effect, total routing time is increased 83.8% than conventional PCB system. In this paper we developed high speed PCB auto-routing system without memory waste by using shaped type applicant with auction algorithm which reaching the destination from one-point with best speed and solving the path problem. Also, this system developed by Visual C++ in IBM Pentium computer Window environment, and compatible with other PC.
A Low Power Resource Allocation and Scheduling Algorithm for High Level Synthesis
Sin, Mu-Kyoung ; Lin, Chi-Ho ;
The KIPS Transactions:PartA, volume 8A, issue 3, 2001, Pages 279~286
This paper proposes a low power resource allocation and scheduling algorithm that minimized power consumption such as DSP circuit in high-level synthesis process. In this paper, we have used list-scheduling method for low power design in scheduling step. Also, it increase possibility to reuse input through resource sharing when assign resource. After scheduling, the resources allocation uses the power function in consideration of the result of calculating average hamming distances and switching activity between two input. First, it obtain switching activity about input value after calculate average hamming distances between two operator and find power value make use of bit pattern of the input value. Resource allocation process assign operator to minimize average hamming distance and power dissipation on all occasions which is allocated at each control step according to increase control step. As comparing the existed method, the execution time becomes fast according to number of operator and be most numberous control step. And in case of power that consume, there is decrease effect from 6% to 8% to be small.