• 한국항공우주학회지
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• 제35권5호
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• pp.412-418
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• 2007

본 논문에서는 충돌각 구속조건을 갖는 비행체 호밍 제어 유도법칙에 대한 역최적 문제를 제시한다. 편향비례항법 유도법칙의 이득과 LQ 문제에서의 가중치와의 관계를 규명하고, Riccati 방정식으로부터 제어입력이 LQ 최적제어가 되기 위한 영역을 제시한다. 이를 근거로 종말 구속조건을 만족하는 호밍 유도법칙의 제어이득이 최적제어법칙이 되기 위한 범위를 제안한다. 이론적 해석 결과의 타당성은 3-DOF 모의시험을 통하여 확인한다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.811-814
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• 2001

Warpage analysis of bobbin, molded by injection molding process was performed. Concerned with a mold design, cooling system was designed based on Taguchi method, the distance between cavity wall and cooling channel was most influent factor amongst four design variables like an inlet temperature of coolant, a coolant flow rate, a diameter of cooling channel, and the distance between cavity wall and cooling channel. Optimal packing processes to reduce the warpage of molded part was analyzed based on the response surface method by considering holding pressure. Their optimal processing conditions were 9.4 seconds, 5.3 seconds, 15.2 seconds, and 85MPa, respectively.

• Journal of Biosystems Engineering
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• 제41권4호
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• pp.373-388
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• 2016

Background: Recent inquiries into high-quality foods have discussed the importance of the functional aspects of foods, in addition to traditional quality indicators such as color, firmness, weight, trimming loss, respiration rate, texture, and soluble solid content. Recently, functional Chinese cabbage, which makes up a large portion of the vegetables consumed in Korea, has been identified as an anticancer treatment. However, the investigation of practical issues, such as the effects of storage conditions on quality indicators (including functional compounds), is still limited. Purpose: We reviewed various studies on variations in the quality indicators and functional compounds of Chinese cabbage in response to different storage environments, focusing on storage temperature and storage period. In particular, we emphasized the effect of storage temperature and storage period on glucosinolate (GSL) levels, in order to provide guidelines for optimizing storage environments to maximize GSLs. Additionally, we used response surface methodology to propose experimental designs for future studies exploring the optimal storage conditions for enhancing GSL contents. Review: Large variations in quality indicators were observed depending on the cultivar, the type of storage, the storage conditions, and the harvest time. In particular, GSL content varied with storage conditions, indicating that either low temperatures or adequate air composition by controlled atmospheric storage may preserve GSL levels, as well as prolonging shelf life. Even though genetic and biochemical approaches are preferred for developing functional Chinese cabbage, it is important to establish a practical method for preserving quality for marketability; a prospective study into optimal storage conditions for preserving functional compounds (which can be applied in farms), is required. This may be achievable with the comprehensive meta-analysis of currently published data introduced in this review, or by conducting newly designed experiments investigating the relationship between storage conditions and the levels of functional compounds.

• 대한전자공학회논문지
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• 제10권5호
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• pp.16-20
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• 1973

많은 검지방식중 어떠한 방식에 의하든 간에 교통류에 관한 정보수집이 선행되어야하고, 그 다음에 정상주기방식이든 전술제어등 비정주기방식이든 간에 교통신호등의 신속제어시에 그 최적신호주기설정을 전제로 하고서 신호주기에 포함되어 있는 발진지연현상에 관하여 분석검토치 않으면 안된다. 선상에서 차의 속도별 및 앞뒤차간의 간격등으로 분포교통량의 개개가 일률적인 인자라 볼 수 없는 것은 사실이나 좀더 구체적으로 그 요인을 제어공학적 해석방법으로써 분석하여 이들을 각각 외란들로 간주하고 나아가 합성외란을 입력과 출력의 차인 오차로 간주했다. 외란은 시간의 함수이므로 첫째 환경조건으로써 도로의 상태 및 기후, 둘째 차량자체의 구조 및 성능으로부터 오는것, 세째 운전자(입간)의 정신적 신체적조건등으로 구분하여 검토하고 본논문은 기존환경조건을 최대로 활용하는 견지에서 첫째의 경우를 일정하다고 보고, 다만 차와 운전자에 대한것만 요인으로 취하였다. 안정화 대책으로써 오차요소별 최소화를 시도했으며, 그 결과 신원최적제어주기설정을 위한 방안이 구체적으로 제시되었고, 주로 외란의 요인을 제거하므로써 최적제어가 가능케됨을 입증해주고 있다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2001년도 춘계학술대회 논문집
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• pp.106-109
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• 2001

The use of ceramic inserts in hot extrusion dies offers significant technical and economic advantages over other forms of manufacture. These potential benefits can however only be realized by optimal design of the tools so that the ceramic inserts are not subjected to stresses that lead to their premature failure. In this paper, process simulation and stress analysis are thus combined during the design, and a data exchange program has been developed that enables optimal design of the dies taking into account the elastic deflections generated in shrink fitting the die inserts and that caused by the stresses generated in the process. The stress analysis of the dies is used to determine the stress conditions on the ceramic insert by considering contact and interference effects under both mechanical and thermal loads. The results are compared with the experimental ones for verification.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2008년도 정기학술발표대회 논문집
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• pp.694-697
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• 2008

건설 생애 전 주기 중에서 기획단계의 지반 조사로 시작되는 흙막이 공법의 선정은 잘못 선정될 경우 해당 프로젝트의 공사비와 공기에 끼치는 영향이 매우 크다. 그렇기 때문에 공법 선정의 요인 및 프로세스에 관련된 연구가 많이 발표되었지만 일반인들의 활용이 어려워 실용화되지 못하고 있다. 본 연구에서는 본 연구의 선행연구에서 개발한 흙막이 공법 선정 프로세스에 기반하여 웹 기반 의사결정 지원시스템을 개발하였다. ASP.NET을 이용하여 사용자들의 접근성을 높이고 자료의 보완 및 수정이 용이한 웹 기반 시스템인 Dr. Underground로 발전시켰다. 이 의사결정 지원 시스템은 일반인들이 쉽게 접근하여 건축물 기본요구 사항과 대지 조건, 인접 대지 조건을 입력하면, 해당 프로젝트에 적절한 흙막이 공법을 선정해주고 그에 대한 상세 정보를 제공해준다.

• Natural Product Sciences
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• 제21권2호
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• pp.141-145
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• 2015

Hesperidin, which is the most abundant flavonoid of Citrus unshiu (Rutaceae), has been reported to possess diverse activities and widely used as functional foods and cosmetics. For the development of functional products, extraction procedure is indispensable. Extraction conditions affect the composition of extract as well as its biological activity. Therefore, we tried to optimize extraction conditions such as extraction solvent, extraction time and extraction temperature for maximum yield of hesperidin using response surface methodology with threelevel-three-factor Box-Behnken design (BBD). Regression analysis showed a good fit of the experimental data and the optimal condition was obtained as ethanol concentration, 59.0%; temperature $71.5^{\circ}C$ and extraction time, 12.4 h. The hesperidin yield under the optimal condition was found to be $287.8{\mu}g$ per 5 mg extract, which was well matched with the predicted value of 290.5 μg. These results provides optimized extraction condition for hesperidin and might be useful for the development of hesperidin as functional products like health supplements, cosmetics and medicinal products.

• Journal of Ecology and Environment
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• 제48권2호
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• pp.128-136
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• 2024

Background: Prasiola japonica is a freshwater green algae species that can only be seen in Korea and Japan. The various conditions necessary for its growth and reproduction have not been fully elucidated. Therefore, in this study, we aimed to investigate conditions related to the growth and reproduction of P. japonica for the purpose of conserving and producing this species. We first examined differences in growth according to various conditions in different habitats to understand the growth environment of P. japonica. Results: The experimental results revealed that the optimal temperature for growth and reproduction of P. japonica was between 10℃-15℃, and the optimal light intensity was 1,000-1,500 lux. Furthermore, when Provasoli enriched seawater with iodine (PESI) agar was used, the growth of P. japonica was found to be at least 1.5-8 times greater than that of the general Sohan Valley water sample, and it also showed 2-4.5 faster growth rate to reach 30 ㎛. These results emphasize the importance of PESI agar in the culture of P. japonica, and are expected to be helpful in suggesting ways to utilize and conserve P. japonica resources. Conclusions: Through these research findings, we suggest new methods for conserving and producing P. japonica, highlight the importance of preserving the P. japonica ecosystem, and explore ways to utilize P. japonica resources. This research promotes the understanding and protection of P. japonica resources in Korea and beyond, and underscores the need for further research and conservation efforts.

• 한국항해항만학회지
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• 제34권1호
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• pp.59-64
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• 2010

본 연구는 마리나 건설 최적의 대상지를 결정하기 위하여 여러 가능해역 중에서 최적의 장소를 결정하는 것이다. 마리나 건설 후보지 선정 문제를 다루기 위해서 여수시 인근의 10개의 후보지를 대상으로 10개의 결정 요인들을 분석하여 최적의 장소를 선정한다. 본 논문에서는 가장 합리적인 장소를 결정하기 위하여 새로운 모델인 0-1정수 최적계획모형이 제안된다. 제안된 모형은 지금까지 최적 마리나 시설 분석 문제에 적용된 사례가 없다. 본 논문은 가장 합리적인 장소를 결정하는데 기여할 뿐만 아니라 제안된 모형은 타 지역의 마리나 시설 건설 후보지 선정 문제에도 적용할 수 있다.

• 한국염색가공학회지
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• 제34권3호
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• pp.197-206
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• 2022

The purpose of this study was to confirm the optimal spinning conditions for PLA (Polylactic acid) as a fiber forming polymer. According to the melt spinning test results of PLA, the optimal spinning temperature was 258℃. However, it needs to note that relatively high pack pressure was required for spinning at 258℃. At an elevated temperature, 262℃, mono filament was broken easily due to hydrolysis of PLA at a higher temperature. In case of fiber strength, it was confirmed that the draw ratios of 2.7 to 3.3 were optimal for maximum strength of melt spun PLA. Above the draw ratio, 3.3, the strength of the PLA fibers was lowered. It was presumed that cleavage of the PLA polymer chain over maximum elongation. The heat setting temperature of GR (Godet roller) showed that the maximum strength of the PLA fibers was revealed around 100℃. The degree of crystallinity and the strength of the PLA fibers were decreased above 100℃. The optimal take-up speed (Spinning speed) was around 4,000m/min. Thermal analysis of PLA showed 170℃ and 57℃ as Tm (melting temperature) and Tg (glass transition temperature), respectively.