• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.11B
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• pp.961-967
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• 2008

Congestion control is one of major mechanisms to avoid dropped packets. Many researchers use optimization theories to find an efficient way to reduce congestion in networks, but they do not consider robustness that may lead to unstable network utilities. This paper proposes a new methodology in order to solve a congestion control problem for wired networks by using a robust design principle. In our particular numerical example, the proposed method provides robust solutions that guarantee high and stable network utilities.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.759-761
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• 2003

This test was performed to improve the cavitation property on hydro-turbine and the optimum quantity of aeration. Vibration and noise change according to hydro-turbine load. The results of aeration tests applied to chungju hydro-turbine.

• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.45-47
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• 1993

Load Management, is originated from efficiency improvement of energy use, or energy conservaion. Traditionally, electric utilities have constructed new power plants to meet the steadily increasing electricity demand. Power development planning, however, is becoming more difficult in the countries like Korea, Japan, and the United States, and increasing concerns about global environmental problems necessitate changes from existing supply-side options based on fossil-fuel to environmentally agreeable supply strategies. This paper discusses the demand side management strategy with emphasis on the concept, implementation scheme, and current practices employed in utilities.

• JOURNAL OF ELECTRICAL WORLD
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• no.8 s.92
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• pp.28-31
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• 1984

• Journal of Korean Society of Water and Wastewater
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• v.21 no.4
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• pp.453-465
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• 2007

With rapid expansion of the water market and growth of water companies, the recent trends in international water industry show that standardization of service activities concerning management of water and wastewater system (ISO/TC 224, to be issued in the second half year of 2007) is expected to have a large influence on the global water market including liberalization of water service market. In the Draft International Standard(DIS) of ISO/TC224, Performance Indicators(PIs) are suggested to estimate the service activities relating to water and wastewater treatment facilities. PIs have been developed in many countries including some international organization(World Bank, IWA and etc.) for service benchmarking. To evaluate public service level and establish plans to improve service level of wastewater utilities, we developed PIs for 120 items and applied them to 10 sewage utilities in the consideration of their scales, circumstances and conditions. In this study, we verified the applicability of the developed performance indicators(PIs). So, we concluded that PIs developed for the purpose of this study can be a useful tool applicable to objective evaluation of the service level of sewage utilities. Using the evaluation tool of PIs developed, it can also be used as a benchmarking tool in this industry as well as for enhancing the efficiency of operation and management of the sewage system. It will also contribute to the water resource management through determination of investment priorities based on the evaluation results and to raising international competitiveness of the domestic sewage utilities to meet the future opening of the water market.

• Korean Journal of Social Welfare
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• v.61 no.3
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• pp.179-204
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• 2009

This paper attempts to explain the effect and application of action research in Korean social welfare research and discusses utilities of action research in the broadening and deepening social welfare body of knowledge within Korea. First, this paper examines the concepts, characteristics, and relevant literatures of action research. Second, this paper attempts to explain the effect, meanings, and application of action research in Korean social welfare research with examples from study on development of user involvement manuals for the disabled residential facilities for the first time in Korea. Third, this paper discusses utilities of action research in broadening and deepening social welfare knowledge body in Korea. In discussing the utilities, this paper maintains that action research can be more properly utilized for research methods to decrease the gab of research and social work practice. Finally, this paper highlights that 'many ways of knowing' exist in social science and it should be considered more sincerely in the arena of Korean social welfare research in order to more solidly develop the knowledge body of social welfare and practice in Korea.

• Hwankyungkyoyuk
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• v.10 no.2
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• pp.239-248
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• 1997

This survey is related to the status of education for environmental managers, who are taking charge of pollution control untilities, and its analyses. This survey is also discussing the improvements of educational course for the trainees, who have already been educated in environmental background as well as its problems. The 45% of in-service trainees were those who had graduated more than a junior college. But under the 50% of them were those who had school careers of less than a high a high school, which means that the trainees have trouble in acquiring the professional knowledges on environmental educations such as the lectures and the practice educations. All over the country, 46 junior colleges, and 65 universities which have a environmental education program, have produced the graduates who major in the environment. Therefore, it is demanded that they should be properly treated. In this research work, it is shown that the 76% of environmental managers have no certificate of environmental study. It is thought that this has resulted from the released environmental law; the untilities of the first and second grade need a manager with a certificate related with environment, the third grade utilities only need a manager with a non-specified certificate related with environment or a manager with more than 3 years environmental practice careers, the fourth and fifth grade utilities do not need the certificate related to environment. In view of relation between environment pollutions and the management of environmental utilities, it is thought that present environmental laws should be improved to be strict. The fact that the differences in regions or utilities are not considered in the contents of texts, has reduced the efficiency of education. Therefore, it is needed that the experts and the in-service managers should take part in the development of the text. In this survey, the more than 20% of trainees have negative opinions about the result of this education, which means that overall the environmental practice education should be reconsidered. In the educational methodology, more than 50% of trainees have the opinion that they want spot speciations, the audio-visual educations and the practice. Therefore, it is demaned that the subjects, syllabus, and the allotment of time ect, should be reorganized for the more practical education.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.3
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• pp.495-502
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• 2020

In this paper, a power management circuit was designed to drive the emergency lighting LED in the underground facility for public utilities using magnetic energy harvest. The magnetic energy harvest consists of a harvest elements and power management circuits. The proposed circuit was made of a rectifier, a battery charging circuit, and an LED driving circuit. In normal times, the battery is charged with the harvested power, and in the event of an emergency, the energy stored in the battery is used to drive the LED. As a result of the measurement, it took two minutes to charge the 47 mF capacitor. This is the amount of power that can drive an LED for emergency lighting for about three and a half minutes. Through this, it was confirmed that the power management circuit for magnetic energy harvest proposed in this paper can be used as an emergency lighting LED-driven power device in an underground facility for public utilities where it is difficult to draw separate power.

• Korean journal of food and cookery science
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• v.24 no.3
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• pp.325-332
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• 2008

The purpose of this study was to analyze the gap in perceived sanitaion management importance-performance for school foodservice facilities and utilities. Questionnaires were delivered to 200 dietitians who are employed in school foodservice. A total of 108 were usable, resulting in an 54.0% response rate. Statistical analyses were performed using the SAS package program(version 8.2 for Windows) for descriptive analysis, t-tests, and importance-performance analysis (IPA). Among the respondents, 58.3% of the dietitians had more than 10 years of work experience, 81.5% were university graduates, and 64.8% worked in elementary schools. Also, 89.8% of the school foodservices provided meals once a day. According to the importance and performance analysis for 25 items, significant differences were found between importance and performance and the importance score was significantly higher than the performance score for all of the items. The results of IPA showed the following areas as improvement priorities: physical separation between the clean areas and the unclean areas to prevent cross-contamination, and proper management of the temperature and humidity within kitchens and food storage facilities. Overall, the IPA results indicated that the items in need of urgent need of improvement will require political support, and above all, continued research. Finally, better models of foodservice facilities and utilities are needed to improve and modernize the operating conditions of these various foodservice establishments.

• Korean Chemical Engineering Research
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• v.46 no.1
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• pp.147-155
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• 2008

The economics of most chemical plants are heavily dependent upon the management of the utilities used in the plants. The utilities are supplied by the centralized utility system of the plant. Among the various utilities the steam is by far the most important energy source and the management of the electricity and the process water are greatly affected by the steam. Therefore it is necessary to educate students and new employees the basic concepts about the effective distribution of the utilities and the fundamental strategies to apply the concepts in actual plant operations. The OOUS (Optimal Operation of Utility System) is an GUI educational system designed to educate the effective generation of the steam and the optimal steam distribution schemes within short period. The OOUS deals with various utility equipments and processes and shows how to save operation costs by displaying the optimal operation conditions based on the process models and the operational knowledgebase.