• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.798-800
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• 2005

In competitive electricity markets, the System Operator (SO) coordinates the overall maintenance schedules whenever the collective maintenance schedule reported to SO by Gencos & Transco in the pool does not satisfy the specified operating criteria, such as system reliability or supply adequacy. We propose a two-layer mathematical algorithm amenable to maintenance scheduling problem into master problem and sub-problem. The master problem coordinates the scheduling, and sub-problem, DC optimal power flew, checks the adequacy. The proposed algorithm was demonstrated with a case study.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.4
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• pp.393-399
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• 2009

Historically, industrial condition monitoring has been performed by costly hard-wired sensors or infrequent checks by maintenance personnel equipped with hand held monitoring equipment. Self- powered wireless condition monitoring systems provides on-line monitoring of critical plant and machinery providing major operating cost benefits. A vibration energy harvester(VEH) is a device that converts kinetic energy occurred by machine vibration into useable electrical energy. Using VEHs to power wireless monitoring systems can yield significant benefits: increased reliability, lower life time costs and no battery disposal issues, etc. This paper proposes the novel prototype design and manufacturing of a VEH that can eliminate the effect by failed batteries.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.623-629
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• 2008

A periodic inspection for facilities in operation is an inspection that is carried out regularly, in which inspection cycles are drawn up, and it is a series of tests to determine if the condition of all the equipment is maintained, and to identify whether they are to be used or replaced. Reliability should be enhanced, without a breakdown, by preliminary inspection and regular checks for each equipment item installed for equipment maintenance. It was noticed that there was a slight difference for the same facility, and for each organization in terms of inspection cycles and methods while preparing procedures of periodic inspection checklist, inspection methods and cycles for a related organization. Therefore, this paper reviews the optimal methods of inspection procedures for Seoul Metro.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.321-328
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• 1998

A controller and sensor fault tolerant system jot a steam generator is designed with fuzzy logic. A structure of the : proposed fault tolerant redundant system is composed of a supervisor and two fuzzy weighting modulators. A supervisor alternatively checks a controlled and a sensor induced performances to identify Which Part, a controller or a sensor, is faulty. In order to analyze controller induced performance both an error and a charge in error of the system output an chosen as fuzzy variables. The fuzzy logic jot a sensor induced performance uses two variables : a deviation between two sensor outputs and its frequency, Fuzzy weighting modulator generates an output signal compensated for faulty input signal. Simulations show that the : proposed fault tolerant control scheme jot a steam generator regulates welt water level by suppressing fault effect of either controllers or sensors. Therefore through duplicating sensors and controllers with the proposed fault tolerant scheme, both a reliability of a steam generator control and sensor system and that of a power plant increase even mote.

• Asia pacific journal of information systems
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• v.8 no.3
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• pp.147-163
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• 1998

Advances in information and telecommunications technology are producing unprecedented shifts in the way businesses conduct their business, Today, electronic commerce is becoming pervasive due to, in large part, the widespread use of Internet and Worldwide Web. One element that plays an important role in shaping the success of electronic commerce is the electronic payment system. Deficiency in its reliability and security may lead to unwanted outcomes, including economic losses and customer dissatisfaction. By far, numerous forms of electronic payment systems have been introduced in the virtual marketplace. However, there exists little research that has focused on the characteristics of the electronic payment systems such that they may be compared with one another. This article is aimed at providing a framework for comparative analysis of electronic payment systems, examining the characteristics of the individual payment systems, and suggesting a choice strategy which enables a firm to select an appropriate payment system suited to their business needs. The framework classifies electronic payment systems into four categories including electronic cash, electronic checks, credit cards, and smart cards, and it can be employed in planning for an electronic commerce system.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.3
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• pp.335-339
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• 2010

In this paper, in order to reduce the electrical disaster damage which is caused by with electrical equipment of traditional markets, we developed the cabinet panel and the electrical safety monitoring system which is able to monitor the electrical equipments condition(over current, leakage current, arc, WH, electrical fire factor etc.) at traditional markets. We constructed Test-bed for testing reliability of electrical safety monitoring system and cabinet panel. And we tested the cabinet for over current, leakage current and arc under the traditional markets actual condition. This paper will be used with the data for an demonstration project after compensating the defects which are occurred to operation of traditional markets actual loads.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.737-739
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• 1996

Abnormal conditions and disturbances in distribution system cause an immediate influence to the customers. Conventional detection schemes for the distribution abnormalities have been applied in limited extents mainly because of their low reliability. In this paper, we developed a disturbance identification system which monitors the load level after a transient, checks the harmonic behavior of the load, and finally makes decision on the cause of the disturbance. This system identifies and discriminates overcurrent faults, arcing ground faults, recloser activities, and foreign object or tree contacts. In the implementation of the identification system, we applied fuzzy logic to better represent some variables whose Quantities are expressed only in non-numerical terms.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.10a
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• pp.351-353
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• 2022

There have been several nuclear accidents at home and abroad so far, and there have been major and small damages. Overseas, in order to reduce such accidents, the safety and reliability of nuclear power plant operations have been improved by introducing a technology called Configuration Management. Through basic information on Configuration Management and successful cases of introducing Configuration Management from overseas nuclear power plants, this paper checks the technical parts applicable to Korea and examines whether they can be newly applied by supplementing them for domestic nuclear power plants.

• FOCUS: LIFE SCIENCE
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• no.1
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• pp.8.1-8.3
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• 2024

Ultra-high performance liquid chromatography (UHPLC) systems are integral to modern analytical laboratories, necessitating careful maintenance and operation protocols to ensure optimal performance. This document provides comprehensive guidelines for the proper shutdown and reactivation of UHPLC systems to prevent damage and maintain operational efficiency. • Shutdown: Remove the column and replace it with a union to avoid blockages. Flush the system with a compatible solvent mix, clean mobile phase reservoirs to prevent microbial growth, flush the pump with storage solvent, and clean the autosampler, including the needle and injection port. • Reactivation: Inspect the system for wear or damage, gradually reintroduce mobile phases starting with a weak solvent, reinstall the column securely, and perform system checks on baseline stability, pressure consistency, and detector performance. By adhering to these guidelines, laboratories can ensure the longevity and reliability of their UHPLC systems, maintaining high analytical performance and minimizing downtime. These procedures help prevent common issues such as blockages, contamination, and component wear, thereby supporting efficient and accurate analytical operations.

• Korean Journal of Cognitive Science
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• v.19 no.3
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• pp.223-255
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• 2008

In this paper, we introduce an automatic system of scoring English essays. The system is comprised of three main components: a spelling checker, a grammar checker and a lexical cohesion checker. We have used such resources as WordNet, Link Grammar/parser and Roget's thesaurus for these components. The usefulness of an automatic scoring system depends on its reliability. To measure reliability, we compared the results of automatic scoring with those of manual scoring, on the basis of the Kappa statistics and the Multi-facet Rasch Model. The statistical data obtained from the comparison showed that the scoring system is as reliable as professional human graders. This system deals with textual units rather than sentential units and checks not only formal properties of a text but also its contents.