• KIISE Transactions on Computing Practices
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• v.23 no.10
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• pp.605-610
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• 2017

In distributed environments, dynamic partitioning is needed to resolve the load on a particular server or the load caused by communication among servers. In heterogeneous environments, existing dynamic partitioning schemes can distribute the same load to a server with a low physical performance, which results in a delayed query response time. In this paper, we propose a dynamic partitioning scheme for large RDF data in heterogeneous environments. The proposed scheme calculates the query loads with its frequency and the number of vertices used in the query for load balancing. In addition, we calculate the server loads by considering the physical performance of the servers to allocate less of a load to the servers with a smaller physical performance in a heterogeneous environment. We perform dynamic partitioning to minimize the number of edge-cuts to reduce the traffic among servers. To show the superiority of the proposed scheme, we compare it with an existing dynamic partitioning scheme through a performance evaluation.

• Journal of Communications and Networks
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• v.8 no.1
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• pp.13-20
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• 2006

In cellular mobile communications, how to achieve optimum system capacity with limited frequency spectrum is one of the main research issues. Many dynamic channel assignment (DCA) schemes have been proposed and studied to allocate the channels more efficiently, thus, the capacity of cellular systems is improved. Reuse partitioning (RP) is another technique to achieve higher capacity by reducing the overall reuse distance. In this paper, we present a network-based DCA scheme with the implementation of RP technique, namely dynamic reuse partitioning with interference information (DRP-WI). The scheme aims to minimize the effect of assigned channels on the availability of channels for use in the interfering cells and to reduce their overall reuse distances. The performance of DRP-WI is measured in terms of blocking probability and system capacity. Simulation results have confirmed the effectiveness of DRP-WI scheme. Under both uniform and non-uniform traffic distributions, DRP-WI exhibits outstanding performance in improving the system capacity. It can provide about 100% capacity improvement as compared to conventional fixed channel assignment scheme with 70 system channels.

• Journal of KIISE
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• v.41 no.12
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• pp.1126-1135
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• 2014

In recent years, RDF partitioning schemes have been studied for the effective distributed storage and management of large-scale RDF data. In this paper, we propose an RDF dynamic partitioning scheme to support load balancing in dynamic environments where the RDF data is continuously inserted and updated. The proposed scheme creates clusters and sub-clusters according to the frequency of the RDF data used by queries to set graph partitioning criteria. We partition the created clusters and sub-clusters by considering the workloads and data sizes for the servers. Therefore, we resolve the data concentration of a specific server, resulting from the continuous insertion and update of the RDF data, in such a way that the load is distributed among servers in dynamic environments. It is shown through performance evaluation that the proposed scheme significantly improves the query processing time over the existing scheme.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.8
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• pp.1311-1321
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• 1997

In multibody dynamics, differential and algebraic equations which can satisfy both equation of motion and kinematic constraint equation should be solved. To solve these equations, coordinate partitioning method and constraint stabilization method are commonly used. In the coordinate partitioning method, the coordinates are divided into independent and dependent and coordinates. The most typical coordinate partitioning method are LU decomposition, QR decomposition, and SVD (singular value decomposition). The objective of this research is to find an efficient coordinate partitioning method in the dynamic analysis of flexible multibody systems. Comparing two coordinate partitioning methods, i.e. LU and QR decomposition in the flexible multibody systems, a new hybrid coordinate partitioning method is suggested for the flexible multibody analysis.

• Journal of KIISE
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• v.42 no.2
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• pp.177-182
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• 2015

The era of multi-core processors has begun since the limit of the clock speed has been reached. These days, multi-core technology is used not only in desktops, servers, and table PCs, but also in smartphones. In this architecture, there is always interference between processes, because of the sharing of system resources. To address this problem, cache partitioning is used, which can be roughly divided into two types: software and hardware cache partitioning. When it comes to dynamic cache partitioning, hardware cache partitioning is superior to software cache partitioning, because it needs no page copy. In this paper, we compare the effectiveness of hardware and software cache partitioning on the AMD Opteron 6282 SE, which is the only commodity processor providing hardware cache partitioning, to see whether this technique can be effectively deployed in dynamic environments.

• Journal of applied mathematics & informatics
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• v.33 no.1_2
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• pp.211-217
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• 2015

A dynamic spectrum access scheme with channel partitioning for secondary handover calls in cognitive radio networks is proposed to reduce forced termination probability due to spectrum handover failure. A continuous-time Markov chain method for evaluating its performance such as blocking probability, forced termination probability, and throughput is presented. Numerical and simulation results are provided to demonstrate the effectiveness of the proposed scheme with channel partitioning.

• Journal of the Korean Society for Railway
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• v.5 no.3
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• pp.174-180
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• 2002

In multibody dynamics, DAE(Differential Algebraic Equations) that combine differential equations of motion and kinematic constraint equations should be solved. To solve these equations, either coordinate partitioning method or constraint stabilization method is commonly used. The most typical coordinate partitioning methods are LU decomposition, QR decomposition, and SVD(singular value decomposition). The objective of this research is to suggest a hybrid coordinate partitioning method in the dynamic analysis of multibody systems containing singular configurations. Two coordinate partitioning methods, i.e. LU decomposition and QR decomposition for constrained multibody systems, are combined for a new hybrid coordinate partitioning method. The proposed hybrid method reduces the simulation time while keeping accuracy of the solution.

• Journal of the Korean Society of Industry Convergence
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• v.4 no.1
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• pp.87-94
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• 2001

In multibody dynamics, differential and algebraic equations which can satisfy both equation of motion and kinematic constraint equation should be solved. To solve this equation, coordinate partitioning method and constraint stabilization method are commonly used. The coordinate partitioning method divides the coordinate into independent and dependent coordinates. The most typical coordinate partitioning method arc LU decomposition, QR decomposition, projection method and SVD(sigular value decomposition).The objective of this research is to find a efficient coordinate partitioning method in flexible multibody systems and a hybrid decomposition algorithm which employs both LU and projection methods is proposed. The accuracy of the solution algorithm is checked with a slider-crank mechanism.

• The KIPS Transactions:PartC
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• v.9C no.5
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• pp.709-718
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• 2002

Cluster based VOD systems require elaborate load balancing and buffer management techniques in order to ensure real-time display for multiuser concurrently. In this paper, we propose a new load balancing technique based on the dynamic buffer partitioning in cluster based VOD servers. The proposed technique evenly distribute the user requests into each service node according to its available buffer capacity and disk access rate. In each node, the dynamic buffer partitioning technique dynamically partitions the buffer to minimize the average waiting time for the requests that access the same continuous media. The simulation results show that our proposed technique decreases the average waiting time by evenly distributing the user requests compared with the exiting techniques and then increases the throughput in each node. Particularly under the overloaded condition in the cluster server, the simulation probes that the performance of the proposed technique is better two times than the Generalized Interval Caching based technique.

• International Journal of Automotive Technology
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• v.4 no.1
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• pp.31-40
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• 2003

W-beam guardrail system has been the most popular roadside safety device around the world. Through large plastic deformation and corresponding energy dissipation, a W-beam guardrail system contains and re-directs out-of-control vehicles so as to reduce the impact damage on the vehicle occupants and the vehicles themselves. In this paper, our recent experiments on 1 : 3.75 downscaled W-beam and the beam-post system are reported. The static and impact test results on the load characteristics, the global response and the local cross-sectional distortion are reveled. The effects of three different end-boundary conditions for the beam-only testing are examined. It is found that the load characteristics are much dependent on the combined contribution of the local cross-sectional distortion and the end-supporting conditions. The energy Partitioning between the beam and the supporting Posts in the beam-Post-system testing were also examined. The results showed that the energy dissipation partitioning changed with the input impact energy. Finally, a simple mass-spring model is developed to assess the dynamic response of a W-beam guardrail system in response to an impact loading. The model's prediction agrees well with the experimental results.