• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.2 no.2
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• pp.147-152
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• 1999

Purpose: The aim of this study was to evaluate the prevalence of H. pylori infection in normal preschool children. Methods: Study population consisted of 220 preschool children aged 2 to 5 years in Seoul, Korea. We measured H. pylori specific IgG antibody using the GAP test IgG kit, and samples with concentrations greater than 20 U/ml were considered positive. Results: Of the 220 children, 5 (2.3%) were positive, and thirteen (5.9%) of 220 were equivocally probable positive. Conclusion: The positive rate of H. pylori infection detected by specific IgG antibody in normal preschool children aged 2 to 5 years was approximately 2.3% to 8.2%. This prevalence rate is still high, compared to that of the West. A better knowledge of the transmission of H. pylori is crucial to formulate recommendations for lowering the rate.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.2
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• pp.167-172
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• 2011

In this paper, a study on variation of an accuracy rate as the gradient of a rifle is shown. In the a state of hostilities, a soldier is not easy to take a shot vertically against the ground. If a soldier shoots as the pistol is inclined, how the accuracy rate is changed. While the pistol is shot, the change of ballistic curve is estimated. And we also verify the accuracy rate through the firing test. Then we compare two results and present some ideas which overcome the decrease of an accuracy rate. Hereafter, it is possible to adapt in the future soldier system and expected that the accuracy rate of the conventional gun is maintained.

• 한국벤처창업학회:학술대회논문집
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• 2017.04a
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• pp.26-26
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• 2017

이 연구의 목적은 실제 창업하여 5년 이상 생존한 편의점이 최적의 입지유형에 위치한 것이 크다는 영향을 증명하는데 있다. 이 목적을 달성하기 위하여 서울 주요 지역의 5년 이상 생존 점포 사례를 본인과 지인의 사례 점포, A 메이저 프랜차이즈 편의점 직원이 제공한 자료를 토대로 연구 결과를 분석하고 실제 창업 생존률을 높이는데 도움을 주고자 한다. 실증분석결과, 첫째로 입지요인은 편의점 성과에 영향을 미치는 것으로 나타났다. 둘째, 최적의 입지유형에 위치한 점포는 5년 이상 생존하는데 영향을 주는 것으로 나타났다. 최적의 입지유형에 위치한 편의점 창업은 5년 이상 생존하는데 상당한 영향을 미치므로 입지유형에 대한 인식과 실전 적용은 필요한 것으로 나타났다. 전체 창업시장으로 보면 편의점과 같이 상품의 동질성이 높은 업종이나 위치에 중점을 둔 창업인 경우 까지 확대하여 창업가의 실패를 줄이고 장기적 생존률을 높일 수 있는 연구가 확대 되어야 할 것이다.

• Journal of agricultural medicine and community health
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• v.22 no.1
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• pp.43-48
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• 1997

To exam infestation rate and removal rate of head louse, we did delousing at 27 primary schools and 19 kindergartens established as an annex to the primary school in Namwon-shi, Jollabuk-do, Korea, from May to December 1995. Total of 3123 subjects were examined ed for the presence of head lice and nits The overall infestation rate was 9.6%, 9.5% in primary school children and 10.1% in kindergarten children. Among 299 infested children, 55 children evaluated by live nit had louse, and 79 children had dead nit. According to distractive research, Ibaek-myon and Songdong-myon revealed high infestation rate of 27.3%, and 21.7% respectively. Infestation rate of primary school was 0 to 50.9%, kindergarten was 0 to 100%. Infestation rate of female children were higher than male in all grades. When we executed one time treatment with PARA$^{(R)}$ aerosol(bioallethrin with piperonyl butoxide), treatment rate of 65.1% was examined, 82.8% was examined in three times of treatment. We concluded that 3 times of treatments interval of 14 days were more effective than one time in the case of treatment of only infested children. In order to prevent the spread of head lice, education of school hygiene and suitable delousing attempts should be executed in the present situation.

• Proceedings of the KIPE Conference
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• 1996.06a
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• pp.35-38
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• 1996

A new high power factor converter using transformer magnetizing energy for power factor correction with a single-switch/single-stage is proposed. The proposed converter gives the good power factor correction, low current harmonic distortions, and tight output voltage regulation. The prototype shows the IEC555-2 requirements are met satisfactorily with nearly unity power factor.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.423-431
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• 1997

A new single-stage/single-switched forward converter with magnetic coupled nondissipa-tive snubber is proposed. The proposed converter gives the good power factor correction (PFC), low current harmonic distortion, and tight output voltage regulation. The prototype shows the IEC 555-2 requirements are met satisfactorily with nearly unity power factor. This proposed converter with magnetic coupled nondissipative snubber is particularly suited for low power level power supply applications.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.400-409
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• 1997

Design of single stage AC/DC converter with high power factor and high efficiency based on half-bridge topology for low power application is proposed. To obtain design equations, modelling and detailed analysis are performed. The proposed converter gives and power factor and high efficiency by employing aynchronous rectifiers. To verify the performances of the proposed converter 90W-converter has been designed. This prototype converter meets IEC555-2 requirements with near unity power factor.

• Journal of the Korea Institute of Military Science and Technology
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• v.18 no.5
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• pp.558-565
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• 2015

The current methods, such as Binomial Probability Distribution or T-test, to calculate the number of samples of Precise Guided Missiles(PGMs) for test and evaluation are statistically problematic to make reasonable decisions thus use the budget efficiently. Also, the method to verify an accuracy rate of the PGMs using these old methods seems to be lack of objectiveness. This paper presents an effective, efficient solution adapted from the clinical medicine testing method of healthcare industry research, which may overcome our problems. This method considers and addresses both manufacturers' and consumers' risk simultaneously. By taking into account the weapon system project characteristics which take a relatively longer time and require higher-level budget, this approach also suggests a reasonable and feasible method to determine the amount of samples of the PGMs and making a criterion to verify an accuracy rate of the missiles that are required to test. Thus, this method is expected to contribute to acquisition and operations of high-reliability PGMs by MND and its field-users.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2002.04a
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• pp.57-58
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• 2002

램제트는 다른 여러 추진시스템에 비하여 획기적으로 증가된 사거리를 가지므로 가용범위의 확대는 물론, 목표물 타격 시 높은 명중률과 낮은 격추율을 가지는 효과적인 추진 시스템이다. 램제트 엔진을 장착한 미사일로는 프랑스의 Griffon, ASMP, 미국의 Bomarc, Talos, 영국의 Bloodhound, Sea dart, 소련의 SA4, SA6 등을 비롯하여 많은 종류가 개발되어 실전 배치되었다. 근래 들어 램제트는 군사전략과 전술적인 목적 이외에도 민간용으로도 그 실용성이 강조되고 있어 그 중요성은 날로 더할 것으로 예측된다. 램제트는 일반적인 공기흡입식 엔진과는 달리 엔진 내부에 기계적으로 구동되는 부분이 없이 충격파를 통과하면서 공기의 압력이 높아지는 현상인 램압축 현상을 이용하여 공기를 압축하게 되므로 엔진의 구조가 간단하고, 상대적으로 높은 비추력과 추력/중량비를 가진다. 램제트는 정지 상태에서는 작동되지 않으며 사용 가능한 최소의 압력비를 줄 수 있는 비행 마하수에 도달해야 램제트가 작동하게 된다. 따라서 이러한 비행속도를 줄 수 있는 별도의 추진장치가 필요하게 되는데 이와 같은 보조 추진장치로 부스터를 사용한다. 부스터가 엔진의 내부에 장착된 램제트를 일제형 램제트 (IRR: integral Rocket Ramjet)라 부르며, 현대의 전략미사일과 민간용 초음속 항공기의 엔진에 도입되어 활발한 연구가 진행 중이다. 램압력을 이용하여 압축하므로 램제트의 설계시 설계점 비행 속도에서 전압력 손실이 최소가 되도록 설계되어야 하며, 이를 실험이나 수치해석을 통해 확인하여야 한다.

• Journal of the Korean Operations Research and Management Science Society
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• v.41 no.3
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• pp.23-36
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• 2016

We consider a model that minimizes the total cost incurred by assigning available weapons to existing targets in order to reduce enemy threats, which is called the weapon target assignment problem (WTAP). This study addresses the stochastic versions of WTAP, in which data, such as the probability of destroying a target, are given randomly (i.e., data are identified with certain probability distributions). For each type of random data or parameter, we provide a stochastic optimization model on the basis of the expected value or scenario enumeration. In particular, when the probabilities of destroying targets depending on weapons are stochastic, we present a stochastic programming formulation with a simple recourse. We show that the stochastic model can be transformed into a deterministic equivalent mixed integer programming model under a certain discrete probability distribution of randomness. We solve the stochastic model to obtain an optimal solution via the mixed integer programming model and compare this solution with that of the deterministic model.