• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.8C
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• pp.729-740
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• 2002

This paper studies the issues arising in the virtual topology reconfiguration phase of Multi-wavelength Routed Optical Networks. This reconfiguration process means to change the virtual topology in response to the changing traffic patterns in the higher layer. We formulate the optimal reconfiguration policy as a multi-stage decision-making problem to maximize the expected reward and cost function over an infinite horizon. Then we propose a new heuristic algorithm based on node-exchange to reconfigure the virtual topology to meet the traffic requirement. To counter the continual approximation problem brought by heuristic approach, we take the traffic prediction into consideration. We further propose a new heuristic reconfiguration algorithm called Prediction based Multi-stage Reconfiguration approach to realize the optimal reconfiguration policy based on predicted traffic. Simulation results show that our reconfiguration policy significantly outperforms the conventional one, while the required physical resources are limited.

• Journal of KIISE:Information Networking
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• v.30 no.1
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• pp.1-8
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• 2003

In this paper. we develop an analytical model to evaluate the virtual topology reconfiguration phase of optical Internet networks. To counter the continual approximation problem brought by traditional heuristic approach, we take the traffic prediction into consideration and propose a new heuristic reconfiguration algorithm called Prediction based Multi-stage Reconfiguration approach. We then use this analytical model to study the different configuration operation policies in response to the changing traffic patterns in the higher layer and the congestion level on the virtual topology. This algorithm persists to decide the optimal instant of reconfiguration easily based on the network state. Simulation results show that our virtual topology management Policy significantly outperforms the conventional one, while the required physical resources are limited.

• Journal of KIISE:Information Networking
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• v.31 no.5
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• pp.460-468
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• 2004

Quality of Service (QoS)-constrained policy has an advantage to guarantee QoS requirements requested by users. Quorum systems can ensure the consistency and availability of replicated data despite the benign failure of data repositories. We propose a Quorum based resource management scheme, which includes a system resource and network resource, both of which can satisfy the requirements of application QoS. We also propose the resource reconfiguration algorithm based on temporal execution time estimation method. Resource reconfiguration means that reshuffling the current available resource set for maintaining the quality level of the resources. We evaluate the effectiveness of resource reconfiguration mechanism with a Heart Hemodynamics analysis. Our approach shows the increase of the stability of execution environment as well as decrease the completion time compare to the method that is not adapted the resource reconfiguration.

• Journal of KIISE:Information Networking
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• v.34 no.2
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• pp.120-133
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• 2007

A multicast tree includes several, possibly a large number of, paths connecting source-receiver pairs, and network failure may disable part of the multicast tree. Reconstruction of the entire multicast tree to recover from a component failure is highly undesirable, because some group members have to suffer service disruptions even though the communication paths to/from them are not affected by the failure. To limit reconfiguration region and to maximize the likelihood of successful reconfiguration, we propose and evaluate a pre-planned reconfiguration policy for QoS multicast sessions. Specifically, we equip a reconfiguration path (RP) with each end-to-end path that connects a source-receiver pair in the multicast tree, and reserve resources in advance along the RPs. Efficient resource-sharing techniques are applied to reduce the amount of resources reserved for RPs but not used in the absence of failures. This way, we prevent uncontrolled competition among different multicast sessions which may simultaneously try to recover from failures. We evaluate the performance of the proposed scheme using simulation on randomly-generated networks. We use the shortest-path routing for QoS multicast sessions, and simulate both source-based and shared multicast trees. The evaluation results indicates that successful pre-planned reconfiguration can be achieved for all group members with reasonable overhead. Our scheme is also shown to adapt well to dynamic changes of group membership.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.11
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• pp.239-249
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• 2019

Recently, the Korean government has implemented a policy to expand renewable energy sources. Large-scale PV systems are being actively interconnected with the distribution system. On the other hand, when a large-scale PV system is installed and operated, the customer voltages could violate the allowable voltage limit due to reverse power flow of the PV system. To overcome these problems, an enhancement method for hosting the capacity of the PV system in a distribution system is being actively conducted. Therefore, to improve the hosting capacity of the PV system, this paper proposes a model of a reconfiguration of the distribution system, which is composed of three sections and three connections based on PSCAD/EMTDC S/W, and proposes an evaluation algorithm for the feeder reconfiguration to maximize an adaption of the PV system. In addition, this paper presents the optimal method of the feeder reconfiguration section to evaluate the maximum capacity of the PV system to keep customer voltages within the allowable voltage limits based on various operation scenarios, such as the capacity of a PV system and section of feeder reconfiguration. From the simulation results based on the PSCAD/EMTDC modeling and evaluation algorithm, it was confirmed that they are a useful and practical tool to enhance hosting the capacity of a PV system in a distribution system.

• Journal of Information Technology Applications and Management
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• v.19 no.4
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• pp.197-212
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• 2012

In this paper, we report the public IT policy case results to restructure informatization level indices for small and medium sized enterprise(SME). The indices restructuring project was initiated by TIPA with the group of experts during 2011, and the newly amended indices was employed as the formal instrument to measure SME informatization level. The critical drivers to reform the indices include simplification for more accurate measurement of SME informatization level, reshaping key representative indices of smart IT to better publicize SME's interest toward advanced IT, and systematic reconfiguration of performance measures which reflect business performance enhancement effect through IT investment. Indeed, the IT performance indices are unified to incorporate the instrument for general SME informatization level survey and IT adoption subsidy's effectiveness appraisal. The procedures and details of logic illustrated in this paper provides useful insight for successful implementation of SME informatization as well as for the better policy deployment of IT subsidization for SMEs.

• Journal of Digital Convergence
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• v.10 no.1
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• pp.349-355
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• 2012

Today, the computing environments is very complex, so researches that endow a system with the self-healing's ability that recognizes problem arising in a target system are being an important issues. However, the existing methodology, the goal for the new requirements for self-healing system developers to model and analyze the constraints that must be greater efforts. Therefore, in this paper are aware of problems detected by the system to solve the problem is the analysis of goal-based scenarios. In addition, there is a pre and post applying a strategy to be dynamically reconfigured to show you how to self-healing. These proposed new requirements for methodology, self-healing reduces the load on the developer's analysis.

• The Journal of the Korea Contents Association
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• v.18 no.3
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• pp.309-319
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• 2018

SELinux is used for system level security in various systems using Linux, and is now being used for device security such as IoT. However, since SELinux has inherent problems of execution time degradation, various studies have been conducted to solve this problem. In this paper, we show that performance can be improved through policy reconfiguration in the environment where the loadable module policy method, which is a general method using SELinux, is applied. By reconfiguring the access query table through the Priority-TE policy that gives priority to the type, it is possible to provide faster execution time for types requiring faster access query performance. This paper introduces the differences between SELinux policy configuration method in Monolithic environment and performance analysis. This can be used as a reference by security administrators or developers in applying SELinux.

• Journal of Digital Convergence
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• v.15 no.12
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• pp.591-604
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• 2017

The purpose of this study was to develop and evaluate the program for convericient reconfiguration in an attempt to change maladjustmental way of thinking among female junior tennis players. For verification of the program, a qualitative analysis and quantitative analysis were carried out. Through the REBT program for convericient reconfiguration, maladjustmental way of thinking among junior tennis players was drawed and interviews with them were subsequently performed. As a result, REBT counseling technique was applied to understand personal psychological problems and to transform maladjustmental and unreasonable way of thinking into rational belief, confirming positivity toward their situation. After all, their athletic performance as well as holistic development was found to be improved. In quantitative analysis, maladaptive thinking scale sports psychology questionnaire and survey for Korean sports performance strategy were both increased post treatment, suggesting that their psychological status became positive as a result of application of psychological prevention. The results of this study showed that athletic performance would be enhanced and growth and development in personality and self-realization would be expected if various psychological problems in adolescent players were progressed in detailed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.841-844
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• 2009

Recently our society is changing from an information era to an ubiquitous era. The centralization of an ubiquitous city has been developing among the countries and cities competitively. At this point, a reconfiguration of proper network environment is very important factor for a city competitive power. The centralization of an ubiquitous city is progressing with two kinds of category divided into existing cities and new cities. For example, Unlike new cities, the existing cities should consider the physical space restriction of communication network configuration because they can not design an underground cord lining. This paper describes the comparison and analysis of ubiquitous proceeding cases between the existing cities and new cities. And also, we investigated infrastructure features of proceeding ubiquitous city which is regarded as a reviving concept for the existing cities. In addition, a political proposal of wireless network configuration is suggested to solve these problems for the ubiquitous city.