• 한국음향학회지
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• 제4권1호
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• pp.16-21
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• 1985

Both shifiting the input signal's frequencies by a fixed frequency and compressing the input signal's bandwidth have been known to be effective in improving the stability margin of public adress systems operating in reverberant spaces. This paper describes the effect of an alternative approach of improving the acoustic-feedback stability and yet maintaining speech inteligibility by bandwidth compression and expansion. Conditions are derived for this technizue to be realized and an experimental system has been made - up. A series of experiments has been performed in small spaces and the results have shown that more than 5dB improvement can be obtained in the stability margin.

• Journal of Power Electronics
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• 제12권1호
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• pp.145-156
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• 2012

These days, the application of electronic power transformers (EPTs) is expanding in place of ordinary power transformers. These transformers can transmit power via three or four wire converters. Their dynamic performance is extremely important, due to their complex structure. In this paper, a new method is proposed for improving the dynamic performance of distribution electronic power transformers (DEPT) by using sliding mode control (SMC). Hence, to express the dynamic characteristics of a system, different factors such as the voltage unbalance, voltage sag, voltage harmonics and voltage flicker in the system primary side are considered. The four controlling aims of the improvement in dynamic performance include: 1) maintaining the input currents so that they are in sinusoidal form and in phase with the input voltages so they have a unity power factor, 2) keeping the dc-link voltage within the reference amount, 3) keeping the output voltages at a fixed amount and 4) keeping the output voltages in sinusoidal and symmetrical forms. Simulation results indicate the potential and capability of the proposed method in improving DEPT behavior.

• 한국철도학회논문집
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• 제15권6호
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• pp.550-557
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• 2012

일반적으로 FMECA는 시스템에 치명적인 영향을 줄 수 있는 장치나 고장모드를 파악하고 우선순위를 판단하여 이를 설계나 시스템 유지보수에 반영할 때 사용할 수 있는 기법이다. 본 논문은 도시철도차량의 차상 신호설비인 ATC/ATO 시스템에 FMECA를 이용하여 도시철도차량의 운전장애 현상을 정량적으로 분석하고 위험요소를 도출한 다음 이를 제거하여 도시철도차량의 운전환경을 개선할 수 있도록 하는데 목적을 두었다. 이를 위해 본 연구에서는 FMECA를 활용한 분석을 통해 ADU 개선방안과 사례를 제시하였다.

• 한국산업융합학회 논문집
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• 제13권1호
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• pp.49-54
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• 2010

Lean 6 sigma has recently been used to describe a management system which combines lean management and 6 sigma. The marriage between Lean manufacturing and 6 sigma has proven to be a powerful tool for cutting waste and improving the organization operations. Time and quality are the most important metrics in improving any company's production and profit performance. lean 6 sigma is a management innovation for improving production efficiency, process quality, cost reduction, investment efficiency and customer's satisfaction. in this paper, Advanced cell line is builded the home appliance goods of the LCD TV final assembly line of domestic company line, training the multi-skilled man and controlling the production information system based on Lean 6 sigma.

• 대한치과기공학회지
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• 제45권4호
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• pp.111-117
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• 2023

Purpose: This study aims to determine the status of dental technician's continuing education and licensing reporting and provide basic data that can aid in improving the operation of progressive continuing education and licensing reporting and development programs. Methods: This study included dental technicians nationwide who attended the 2023 Korea Dental Technology Expo & Scientific Conference and responded to an online survey from July 21 to July 23, 2023. In total, 180 copies were analyzed. The reliability of satisfaction with continuing education demonstrated a Cronbach's α of 0.924. IBM SPSS Statistics version 21.0 (IBM) was used to statistically analyze the collected data. Results: Satisfaction with continuing education for dental technicians was 2.78, 2.81, 3.21, 2.96, and 2.87 for the number of lectures offered, composition of major fields, lecture content, instructor level, and overall satisfaction, respectively. The average satisfaction with continuing education was 2.93, which was lower than the average (3 points). The investigation revealed that overall improvement was required. Conclusion: Measures for those who have not completed continuing education must be implemented within the government's legal influence by actively using the license reporting system. Strengthening verification of completion of continuing education, improving autonomous disciplinary rights, diversifying the content and learning methods of continuing education, linking with the license reporting system, improving institutional postevaluation, and introducing related policies should be conducted when opening a dental laboratory.

• 산업공학
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• 제5권2호
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• pp.101-109
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• 1992

The purpose of this paper is to establish a framework of the information system design for the distribution management in the confectionery industry. First, we present the characteristics of distribution information system and the distribution information flow in the confectionery industry. Next, we present a sketch of the computer-communication system as the mechanism for improving communication within the distribution system and design the subsystems of distribution information system. And we design the data structure for manipulating distribution information. Finally, we present the case study in which we design the distribution information system in the confectionery industry.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 1998년도 The Korea Society for Simulation 98 춘계학술대회 논문집
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• pp.106-110
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• 1998

Some successful scheduling systems are based on simulation technique. However, they are relatively expensive. A cost-effective solution is to apply general-purpose simulation software to the scheduling system. This paper is concerned with developing a simulation model for MPS(Master Production Schedule) evaluation system. The target system of the model is PC production system. AIM (Analyzer for Improving Manufacturing system), a well-known manufacturing oriented simulation software, is used for modeling tool. Eventually, the model can be included into an MPS evaluation system as simulation module and a scheduler can use the system to verify the MPS in advance.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전력기술부문
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• pp.73-75
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• 2002

This paper presents the properly method of system security and facility countermeasures. We performed simulation for yearly peak of Korean power system in 2002 under the reactive power problem in a nuclear power plants. Analysis of the problems in power system operation by power flow, fault and stability study. Establishment of power system optimal operating plan by stabilizer and maintaining the reasonable voltage level.

• 한국기록관리학회지
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• 제1권2호
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• pp.121-158
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• 2001

본 연구는 금년 초에 착수한 과학기술종합지식 경영시스템(R&D KMS) 개발 사업을 소개한 것이다. 본 사업은 과학기술부 지원 하에 국내 다수의 과학기술연구소와 개발사업체등이 공동으로 과학기술 연구개발 종사자와 유관기관들 간에 과학기술 지식공유 및 R&D 관리효율성을 위하여 추진된 것이다. 개발된 R&D KMS는 과학기술 지식포털, 지식저장검색시스템, 연구관이시스템 및 R&D그룹웨어 등의 4까지 부문으로 구성된다. 3개년 동안 개발된 이 시스템은 연구개발종사자, 소속기관의 연구개발관리부서는 물론 정부의 과제관리기관의 연구개발활동 및 과제관리를 효율적으로 추진하는 기반이 될 것이다.

• 상하수도학회지
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• 제9권4호
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• pp.97-106
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• 1995

An improving example for traditional rapid mix system was studied in the base of mechanisms of alum coagulation. Local status of the major water treatment plants was also investigated and evaluated for upgrading these plants. A new design and operating criterium for rapid mix system was proposed to velocity gradient, G of $1,000-1,500sec^{-1}$ and detention time, t of 1 sec from the results of experiments and literature reviews. Comparing the present rapid mix system to this criterium, apparent difference existed between them. In this study, for improving Seongnam water treatment plant, a design criterium of velocity gradient, and detention time was set to $1,100sec^{-1}$, 1 sec, respectively. A new rapid mix system adopted the nozzle injection countcurrently cross the inlet pipe to the whole area. The injection velocity was 17m/s, nozzle diameter was 1.0mm, and number of nozzle was 70. The new modified system without running present four 75 HP agitators was able to improve water quality(based on sedimentation effluent) by 15-35% and to reduce electrical energy by 98%.