• Journal of Korea Society of Digital Industry and Information Management
• /
• v.5 no.1
• /
• pp.23-32
• /
• 2009

Although the web is becoming a widely accepted medium, it provides relatively poor performance and low availability. A cluster consists of a collection of interconnected stand-alone computers working together and provides a high-availability solution in application area such as web services or information systems. Web server clusters require a high-availability service with a proactive and practical fault management. However, as the system complexity grows, it is not easy to meet the requirement. Therefore, web server clusters must have self-fault management capability for meeting high-availability requirement. In this paper, we propose high availability web server clusters using self-healing technique with a minimal human intervention. Our experimental results show that a proposed method can be used to improve the availability of web server clusters.

• Journal of the Korean Society of Industry Convergence
• /
• v.14 no.3
• /
• pp.95-100
• /
• 2011

The modern society longing for the convenience of up-to-date technology, there are attempts of miniaturization and high reliance of power equipments in the effectiveness aspect of urban area's usage of space while requiring more electrical energy than now. Consequently, paper used to the Neral Network for a forcasting conservation system. A neral network is powerful asta modeling tool that is able to capture and represent complex input/output relationships. The true power and advantage of neral networks lies in their ability to learn these relationships directly from the data being modeled. Traditional linear models are simply inadequate when it comes to modeling data that contains non-linear characteristics. Form results of this study, the Neral Network is will play an important role for insulation diagnosis system of real site GIS and power eqipment using $SF_6$ gas.

• Proceedings of the KIEE Conference
• /
• 1992.07b
• /
• pp.673-675
• /
• 1992

The operation of condenser-bank is now increasing around Kyoungin area. The operation of condenser-bank is used for the improvement of under voltage and expand of power demand. But the operation has the problem in itself as the switching over voltage. This report deals with the static-condenser fault caused by abnormal operation of circuit breaker which has occurred last summer. We have analyzed this fault using EMTP(electromagnetic transient program).

• Journal of Electrical Engineering and Technology
• /
• v.9 no.6
• /
• pp.1805-1811
• /
• 2014

After an occurrence of a fault in any distribution system, it is desired to limit the effects of the fault to smallest possible area and restore the un-faulty areas as soon as possible. Due the advancements in communication technologies, this task can be achieved in multiple efficient ways. In order to decrease the restoration time in the Smart Grid Distribution Management System (SDMS) a communication based algorithm is proposed in this paper, in which the restoration can be done during reclosing. This paper also analyzes various communication failures with power failures cases including the entire network of communication failures. Results of all these cases have been verified by doing simulations.

• Journal of Electrical Engineering and Technology
• /
• v.12 no.4
• /
• pp.1376-1385
• /
• 2017

This paper proposes a method for estimating the expected frequency of voltage swells caused by asymmetrical faults in a power system. Although voltage swell is less common than voltage sag, repeated swells can have severe destructive impact on sensitive equipment. It is essential to understand system performance related to voltage swells for finding optimal countermeasures. An expected swell frequency at a sensitive load terminal can be estimated based on the concept of an area of vulnerability (AOV) and long-term system fault data. This paper describes an effective method for calculating an AOV to voltage swells. Interval estimation for an expected swell frequency is also presented for effective understanding of system performance. The proposed method provides long-term performance evaluation of the frequency and degree of voltage swell occurrences.

• Journal of Advanced Navigation Technology
• /
• v.13 no.1
• /
• pp.19-26
• /
• 2009

Air Traffic Management (ATM) system requires extremely high reliability for the safe and dependable operations in the airport. This paper reports a study on the reliability of the prototype ATM hardware system including the servers and local area networks. Reliability Block Diagram and Fault Tree Analysis on the prototype ATM hardware were performed.

• Proceedings of the KIEE Conference
• /
• 2000.07a
• /
• pp.412-415
• /
• 2000

Generally, the fault of transmission facilities occurs by natural and artificial causes. Also, these faults are frequently developed by the lightning, a natural phenomenon. Therefore, In this paper, we investigated the case of lightning faults for transmission lines occurred for five years in the west and south of chung-nam province, and then considered a suitable countermeasure for lighting faults in these area

• Proceedings of the KSR Conference
• /
• 2004.06a
• /
• pp.1355-1359
• /
• 2004

In this paper, We elicit the necessity of the Autonomous Decentralized Traffic Control System by analyzing problems of the Centralized Traffic Control System and present operation system. The automatic traffic control system using in large and high-density railway stations is designed and implemented on the basis of the elicited necessity in this paper. It is proposed to use broadcasting protocol for interface of stations in order to ensure autonomy. The result is that advantages of the Autonomous Decentralized Traffic Control System makes on-line expansion and maintenance available. step-by-step construction available. and reduce the area of the influences of system fault when any system fault happens.

• Proceedings of the KIEE Conference
• /
• 2002.07a
• /
• pp.154-155
• /
• 2002

The demand of the power and gas energy have been rapidly increasing with the industralization, therefore, the area where buried pipelines run parallel with the adjacent power lines and cross them increases in Seoul as well as other cities. These situation cause AC interference from the power lines. However, there aren't any standards to preserve the pipelines from AC interference in Korea. This study introduces the separation distance to protection of buried pipeline from arc strikes caused by power line ground fault current. And this study examines and compares the arc distance through case study.

• Proceedings of the KIEE Conference
• /
• 1987.11a
• /
• pp.316-320
• /
• 1987

This paper deals with expert system for power system fault restoration and accompanying numerical data processing. Nowadays, expert system which is a branch or artificial intelligence expands its application area to many fields. And it requires computer language for A.I. to be versatile. Expert system for power system handles numerous numerical data and language for A.I. has its deficiency in numerical data processing. However some recent version of the A.I. language rind ways of overcoming this dilemma by giving the way or linking conventional algorithmic languages to them. This study presents numerical data processing routines described in Turbo prolog which is run in IBM PC and linking numerical data processing routines written in Turbo C to Turbo prolog.