• The Journal of the Acoustical Society of Korea
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• v.4 no.1
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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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• v.12 no.1
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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.

• Journal of the Korean Society for Railway
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• v.15 no.6
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• pp.550-557
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• 2012

In general, FMECA is a technique for identifying failure modes and devices which could result in fatal outcomes. Also it can be used in design or in maintenance through establishing priorities. The purpose of this paper is aimed at improving the driving conditions in advance through analyzing the operation failure phenomena quantitatively with FMECA analysis on the onboard signal system equipped with ATC/ATO, and through deriving the risk factors. This paper suggests an alternative solution for improving the performance of ADU by analyzing a case with FMECA.

• Journal of the Korean Society of Industry Convergence
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• v.13 no.1
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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.

• Journal of Technologic Dentistry
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• v.45 no.4
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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.

• IE interfaces
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• v.5 no.2
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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.

• Proceedings of the Korea Society for Simulation Conference
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• 1998.03a
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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.

• Proceedings of the KIEE Conference
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• 2002.11b
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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.

• Journal of Korean Society of Archives and Records Management
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• v.1 no.2
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• pp.121-158
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• 2001

Development of R&D Knowledge Management System for Science & Technology Research Institutes, which was initiated early 2001, was introduced. The project, funded by the Ministry of Science and Technology, is being carried out by several R&D institutes in cooperation With implementers. The purposes of the project are: sharing knowledge about on-going research progresses and existing research results, facilitating cooperative efforts among research staff, teams, and institutes, and improving the efficiency of research project administration. The system consists of 4 components that are highly intertwined: Knowledge Portal, Knowledge Repository, Project Administration System and Groupware. This 3-year project will benefit R&D researchers, and R&D project carrying-out institutes and government project administration organization by facilitating research and development activities, and improving management efficiency, respectively.

• Journal of Korean Society of Water and Wastewater
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• v.9 no.4
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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%.