• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 A
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• pp.83-85
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• 1995

In a permanent magnet motor, cogging torque arises from the intersection of the rotor magnets with the steel teeth on the stator. This paper describes design measures which can be taken to reduce the cogging torque. In this paper for the optimal shape design of brushless DC motor, evolution strategy is investigated to find the dimension of stator of BLDC motor that minimizes the cogging torque. The corresponding field analysis is performed by two-dimensional finite element method.

• 대한소아치과학회지
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• 제24권3호
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• pp.543-548
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• 1997

The first permanent molar takes important place in the occlusion. Malposition of the lower first molar is frequently due to mesial migration, which is occurred by early exfoliation of the second deciduous molar or proximal caries of deciduous teeth. Above things happen without any consideration of space maintainer, prompt measures for space regaining have to be started. Especially in the case with early loss of the second deciduous molar, it has been said that there is no suitable appliance for maintaining the space before the eruption of the permanent first molar. In distalizing the upper first molar, headgears have been routinely used, which its result was definitely depended on cooperation of the patients. Nowadays, appliances such as pendulum appliances, K-loop, magnets, which can be used without cooperation of the patients, are introduced. Jones Jig, one of the molar distalizing appliances, was used on the patients who visited department of pediatric dentistry in Seoul National University Dental Hospital complaining of no eruption space for the lower second bicuspid. Either removable splint or lingal arch was used as the anchorage. Jones Jig was favorably used in the lower molar, where vestibule is shallow, and this is a case report on the satisfactory result thereof.

• 대한치과기공학회지
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• 제42권2호
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• pp.163-171
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• 2020

Purpose: The purpose of this study is the tooth decay ratio of the children and adolescents in four rural areas of Kyrgyzstan. Methods: Oral examinations were conducted 2,677 children and adolescents in Nizhniy chuy, Bokonbayevo, Chon Tash and Arashan from March 2017 to November 2019. It was investigated decayed tooth ratio(DT), decay permanent tooth ratio(DPT) and missing permanent tooth ratio(DMT) according to ages and areas by direct observation of the oral cavity. Results: In all areas, the rate of all children and adolescents aged 6 to 14 had very high DT of more than 94 percent overall. Furthermore, it was showed that high DPT rates above 78% on average and DMT over 8 years old in Chon Tash and Arashan. Conclusion: These results are higher than the average of DT, DPT and DMT in OECD countries. In order to promote oral health of children and adolescents, increased interest in oral health and policy measures at the Kyrgyzstan government level are considered urgent.

• Journal of Electrical Engineering and Technology
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• 제6권3호
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• pp.375-383
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• 2011

This paper describes a real-time hardware simulator for a grid-tied Permanent Magnet Synchronous Generator (PMSG) wind power system, which consists of an anemometer, a data logger, a motor-generator set with vector drive, and a back-to-back power converter with a digital signal processor (DSP) controller. The anemometer measures real wind speed, and the data is sent to the data logger to calculate the turbine torque. The calculated torque is sent to the vector drive for the induction motor after it is scaled down to the rated simulator power. The motor generates the mechanical power for the PMSG, and the generated electrical power is connected to the grid through a back-to-back converter. The generator-side converter in a back-to-back converter operates in current control mode to track the maximum power point at the given wind speed. The grid-side converter operates to control the direct current link voltage and to correct the power factor. The developed simulator can be used to analyze various mechanical and electrical characteristics of a grid-tied PMSG wind power system. It can also be utilized to educate students or engineers on the operation of grid-tied PMSG wind power system.

• 수산경영론집
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• 제37권2호
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• pp.33-59
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• 2006

This study describes approaches to fisheries management that restrict access by fishers to an area in some way. When fishery closure is established as a technical conservation measure it is a form of input control as a Korea fisheries management system. There are many compelling reasons why a fisheries manager should seriously consider closed areas and/or time restrictions, either as a complement to other measures or as the primary facet of the Korean fisheries management strategy. Fishery closures have been shown to be effective in many fisheries and are an important tool in the management armoury. In many respects justifications for their use and the process of implementation are likely to be relatively straightforward compared to permanent area closures. From a Korean fisheries management perspective, the benefits that flow from fishery closures are usually less easy to predict than for other management measures. Moreover, even if one accepts that implementation of fisherg clossures will provide higher production levels in adjacent fished areas, the potential benefits may often be in danger of being largely dissipated. If, for example, the fishery remains open access, the increased production is likely to attract new entrants into the fishery, thereby driving it back towards bioeconomic equilibrium. From a Korean wider fisheries conservation perspective, however, fishery closures have important and clearly defensible roles to play and some form of zoning arrangement will often effectively serve conservation values. Given the increasing trend towards the establishment of national networks of fisherg closures, it seems likely that fisheries managers throughout the world will need to ensure that they are familiar with the issues surrounding these approaches. The importance of being explicit about the goals for fishery closures in Korea have been continually emphasised throughout this study. There may, of course, be multiple justifications for the measure, in which case it is important to try and specify them in order of priority.

• Asian-Australasian Journal of Animal Sciences
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• 제29권2호
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• pp.170-175
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• 2016

The objective of this study was to assess variance components and genetic parameters for fat and protein content in Tsigai sheep using multivariate animal models in which fat and protein content in individual months of lactation were treated as different traits, and univariate models in which fat and protein content were treated as repeated measures of the same traits. Test day measurements were taken between the second and the seventh month of lactation. The fixed effects were lactation number, litter size and days in milk. The random effects were animal genetic effect and permanent environmental effect of ewe. The effect of flock-year-month of test day measurement was fitted either as a fixed (FYM) or random (fym) effect. Heritabilities for fat content were estimated between 0.06 and 0.17 (FYM fitted) and between 0.06 and 0.11 (fym fitted). Heritabilities for protein content were estimated between 0.15 and 0.23 (FYM fitted) and between 0.10 and 0.18 (fym fitted). For fat content, variance ratios of permanent environmental effect of ewe were estimated between 0.04 and 0.11 (FYM fitted) and between 0.02 and 0.06 (fym fitted). For protein content, variance ratios of permanent environmental effect of ewe were estimated between 0.13 and 0.20 (FYM fitted) and between 0.08 and 0.12 (fym fitted). The proportion of phenotypic variance explained by fym effect ranged from 0.39 to 0.43 for fat content and from 0.25 to 0.36 for protein content. Genetic correlations between individual months of lactation ranged from 0.74 to 0.99 (fat content) and from 0.64 to 0.99 (protein content). Fat content heritabilities estimated with univariate animal models roughly corresponded with heritability estimates from multivariate models: 0.13 (FYM fitted) and 0.07 (fym fitted). Protein content heritabilities estimated with univariate animal models also corresponded with heritability estimates from multivariate models: 0.18 (FYM fitted) and 0.13 (fym fitted).

• 농촌의학ㆍ지역보건
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• 제9권1호
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• pp.27-38
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• 1984

The Family Planning Project as a birthcontrol policy has been enthusiastically carried out by the government since 1962. But gradually it get less enthusiastic. Therefore, it is required to establish a more comprehensive and systematic plan and to carry out it thoroughly. And it is needless to say that people's knowledge about family planning, their attitudes and their practice should be concretly comprehended. Taking these things into consideration, this study surveys the general situation on family planning among 237 married women of less than 34 years in Guro 6-dong, one of target areas for Korea University Health Project from Sep. 17, 1984 to Oct. 13, 1984. The results are as follows; 1) Most of the subjects (62.8%) want 2 children and 13.6% want one child. But son-preference consciousness is remarkably revealed among them, which is thought to cause social inequality between man and woman. Therefore, it needs to change the traditional son-preference convention, for equality of all men regardless of sex. 2) The rate of induced abortion experience by person is 61.6% and the average frequency is 1.4. Almost all the induced abortion are carried out at clinics and hospitals during 2~3 months after conception. To prevent these unnecessary conception and induced abortion in view of maternal health, ethics and economics, proper contraceptive measures should be emphasized. 3) Temporary contraceptives should be sold more widely in the basis of free trade in order to practice the intensive and comprehensive family planning because the degree which Health Center has been utilized for buying temporary contraceptives is low. 4) There are serious problems such as the side effects and the lack of follow up care in permanent contraceptives. Those lower the practice rate of permanent contraception. Therefore it is necessary to improve the quality of permanent contraception practice and strengthen the follow-up care.

• 대한토목학회논문집
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• 제33권5호
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• pp.2147-2156
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• 2013

본 연구는 부산지역 영구임대주택의 주거환경 수준 평가 분석을 목적으로 수행한다. 영구임대주택 정책은 무주택자, 특히 도시지역의 저소득 거주자들을 위한 특별한 방법 중 하나이다. 주거환경에는 그것을 구성하는 여러 요인이 있음에도 불구하고, 정부에서는 단지 물리적인 공간만을 제공하는 한계에 봉착했다. 그래서 영구임대주택의 불만족 등을 개선하기 위한 기초자료를 제공하고자 하고자, 부산도시공사에서 관리하는 영구임대주택 거주자를 대상으로 설문조사를 실시하였다. 이 연구의 결과는 다음과 같다. 영구임대주택 만족도에 월임대료, 관리비등의 관리적 특성들은 거의 영향을 미치지 못 하였고, 거실 방 등의 위치 및 화장실 시설, 통근거리, 조망권, 놀이터 등이 영향을 미쳤다. 주민생활 특성 중에는 청소상태, 고성방가 발생 정도, 주민들과의 친밀도, 방법시설 등이 유의하게 나타났다. 따라서 앞으로 정부는 최신 기술을 최대한 활용하여 영구임대주택 거주자의 편의를 도모하되, 경제적으로 부담이 되지 않을 수준으로 적용하는 것이 중요하다는 것을 인식해야 할 것이다.

• 대한소아치과학회지
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• 제23권4호
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• pp.893-898
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• 1996

The occlusal disharmonies resulted from labially protruded or malpositioned teeth can damage the periodontium and induce the non-inflammatory gingival recession. For these cases, a conservative approach was performed by improving oral hygiene and correcting the axial and positional status of the gingivally recessed teeth and removing the prematurely contacted areas. In some cases, rapid remission of tooth mobility and gradual decrease of gingival recession was observed just after start of treatment. In cases of gingival recession in permanent lower incisors of the children with mixed dentition, the treatment of choice is non-surgical conservative approaches. In cases when the gingival inflammation can be controlled through reinforcing the oral hygiene, when attached gingiva have a potential to increase in width through growth (not more than 1 year after eruption or not yet arrived at adult level), and when the recession can be corrected by moving the teeth from labial cortical plate through orthodontic treatment, the conservative measures would be the first choice. On the contrary, when recession has exceeded beyond the level of CEJ, when the gingival inflammation existed with the cause of poor oral hygiene, when the attached gingiva have little potential to increase (for example, more than 8 years after eruption), and when the conservative measures yielded no benefit after 4-8 weeks of treatment, the surgical approaches should be sought.

• ETRI Journal
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• 제25권1호
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• pp.34-40
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• 2003

This paper considers a TMN-based management system for the management of public ATM switching networks using a four-level hierarchical structure consisting of one network management system, several element management systems, and several agent-ATM switch pairs. Using Jackson's queuing model, we analyze the effects of one TMN command on the performance of the component ATM switch in processing local calls. The TMN command considered is the permanent virtual call connection. We analyze four performance measures of ATM switches- utilization, mean queue length and mean waiting time for the processor directly interfacing with the subscriber lines and trunks, and the call setup delay of the ATM switch- and compare the results with those from Jackson's queuing model.