• 제목/요약/키워드: 정석재

검색결과 312건 처리시간 0.03초

Delft-3D Model을 이용한 다원주 군파일의 파랑제어 효과에 관한 연구 (Study on Effect of Wave Control by Multi-Cylinder Piles Using Delft-3D Hydrodynamic Model)

  • 이상화;장은철;이한승;정석재
    • 한국해양공학회지
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    • 제25권2호
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    • pp.29-35
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    • 2011
  • In order to effectively control waves in a coastal zone, Multi-Cylinder Piles have been suggested as economic structures. A numerical analysis was conducted using the Delft-3D: WAVE module based on SWAN, which considered wave shoaling and refraction. Moreover, irregular waves were used to investigate the hydrodynamic characteristics of the wave interaction with the structure. In this paper, a numerical analysis was carried out to research the effect of wave control through a wave height analysis concerning an existing, concrete wave breaker and multi-cylinder piles placed at the same location. As a result, the effect of the wave control is shown using the wave breaker, multi-cylinder piles, and existing data.

기업 물류비용의 실증적 분석을 통한 공급사슬 전략의 도입 효과분석 (A study on the introduction effect of supply chain strategies using the analysis of enterprise logistics)

  • 이정;정석재;김경섭
    • 한국경영과학회:학술대회논문집
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    • 한국경영과학회 2007년도 추계학술대회 및 정기총회
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    • pp.482-487
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    • 2007
  • As the importance of logistics is increasing, Enterprises design the supply chain(SC) network to minimize the total costs considering inventory holding cost, transportation cost and apply the efficient strategies of supply chain based on SC network Calculating the logistics costs without reflecting the logistics components like the packaging cost, transportation related cost, storage cost, loading & unloading cost, and distribution costs, the companies should have many limitation to calculate the logistics cost of real enterprise and install the SC network reducing them. Therefore, this research is aimed at establishing SC strategies which can be an efficient alternative for a decision making on supply chain, based on existing reference and current logistics networks of 'L' company in Korea and analyzing interaction effects between strategies and influence on logistics cost by these strategies. As the method of analysis, we analyze the interaction effects between strategies as well as install the optimal SC network reflecting concrete logistics components from the viewpoint of total logistics costs. we expect that analysis method of this paper would be applied various industries and used the efficient tools for the decision mating by planing and execution of the logistics budget from enterprises.

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기업 물류비용의 실증적 분석을 통한 공급사슬 전략의 도입 효과분석 (A Study on the Introduction Effect of Supply Chain Strategies Using the Analysis of Enterprise Logistics)

  • 이정;정석재;김경섭
    • 경영과학
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    • 제25권2호
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    • pp.89-109
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    • 2008
  • As the importance of logistics is increasing, Enterprises try to design the supply chain(SC) network to minimize the total costs considering inventory holding cost, transportation cost and apply the efficient strategies of supply chain based on SC network. Despite of this efforts, Calculating the logistics costs without reflecting the real components of logistics like the packaging cost, transportation related cost, storage cost, loading & unloading cost, and distribution costs, the companies has many limitation to calculate the logistics cost of real enterprise. For overcoming such problem, this paper is aimed at establishing SC strategies which can be an efficient alternative for a decision making on supply chain, based on existing reference and current logistics networks of 'L' company in Korea. Also, we analyze the interaction effects between strategies as well as install the optimal SC network reflecting concrete logistics components from the viewpoint of total logistics costs using the simulation and statistic methods. we expect that analysis results of this paper would be applied various industries and be utilized to the efficient tools for the decision making by planing and execution of the logistics budget from enterprises.

Intense Pulsed Light(IPL)를 이용한 알부틴의 경피 흡수 개선 (Enhanced Topical Delivery of Arbutin using Intense Pulsed Light (IPL))

  • 최준호;정석재;심창구;김대덕
    • Journal of Pharmaceutical Investigation
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    • 제39권2호
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    • pp.121-125
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    • 2009
  • The objective of this study was to investigate the feasibility of applying the Intense Pulsed Light (IPL) as a tool to enhance the skin absorption of arbutin, a well-known skin-whitening agent. Arbutin solution or skin formulation was applied on the back of hairless mouse skin in vivo after IPL treatment, and then the skin deposition of arbutin was determined by HPLC. IPL treatment significantly increased the amount of arbutin in the skin after 6 hours when arbutin solution was applied 20 times. IPL also enhanced the skin deposition of arbutin when arbutin formulation was applied, although it was not significantly different. Significant increase of surface skin temperature was observed by IPL treatment, which might be a mechanism of the enhanced skin absorption of arbutin. These results suggest the feasibility of using IPL as a tool to increase the skin absorption of whitening agents, although further research needs to be conducted to understand its exact mechanism.

시나리오 기반 시뮬레이션을 활용한 북한지역 반격 시 물자수송 능력 분석방법 연구 (A Study on Material Transportation Capability Analysis Method in NK using Scenario-based Simulation)

  • 최병권;정석재
    • 한국군사과학기술학회지
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    • 제20권2호
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    • pp.279-288
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    • 2017
  • The Material Transportation Capability Analysis Method in North Korea includes adversary's activities such as destruction of bridge which is one kind of choke points in the road network and surprise attack against resupply march unit. Also, the amount of damage on choke points in the road network and repair time depending on repair unit commitment must be reflected. In this study, a scenario encompassing plausible resupply transportation circumstances while counterattacking into NK will be established. Then, based on such scenario, a simulation model will be established and the result of simulation will be compared to the results of numeric example which has been used in the ROK Army. We demonstrate, through a certain Corps operation area, that the Scenario-based Simulation Model results predict the performance of resupply operation very well. Therefore, it makes sustainment planners and commanders do activities which is suitable for battlefield and should be used in the real situation. It is also a stochastic model.

Cyclosporin A가 봉입된 nanostructured lipid carriers의 물리적 특성연구 (Physical properties of cyclosporin A-loaded nanostructured lipid carriers)

  • 송충길;정석재;심창구;김대덕
    • Journal of Pharmaceutical Investigation
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    • 제38권1호
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    • pp.39-43
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    • 2008
  • Cyclosporin A (CyA), a potent immunosuppressive drug used in allogeneic transplants and autoimmune disease, is a typical water-insoluble drug. Recently, nanoparticle carriers were investigated to improve the intestinal absorption of drugs. In this study, CyA-loaded nanostructured lipid carriers (NLCs) were prepared from a hot o/w emulsion using the high pressure homogenization method. The NLCs were consisted of cationic lipids, solid lipids, liquid lipids (oils), surfactant and stabilizer. Encapsulation efficiency of CyA in NLCs was approximately 71%. The average particle size and zeta potential of NLCs were below 250 nm and above +40 mV, respectively. The morphology of NLCs was confirmed by transmission electron microscopy (TEM) analysis. Compared to the CyA powder, higher in vitro release of CyA from NLCs was observed after burst release within 30 min. Thus, CyA-loaded NLCs could be applied not only for parenteral route but also for gastrointestinal administration, which needs further investigation.

다단계 물류 네트워크에서 A/S 부품 집화 및 배송이 연속적으로 발생하는 문제에 관한 사례연구 -자동차 부품 물류 프로세스를 중심으로- (Case Study on the continuous pickup and delivery vehicle routing problem in Multi-level Logistic Network based on S automobile Part Logistics Process)

  • 송준우;김경섭;정석재
    • 대한안전경영과학회지
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    • 제15권2호
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    • pp.193-204
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    • 2013
  • The growing logistics strategy of a company is to optimize their vehicle route scheduling in their supply chain system. It is very important to analyze for continuous pickups and delivery vehicle scheduling. This paper is a computational study to investigate the effectiveness of continuous pickups and delivery vehicle routing problems. These scheduling problems have 3 subproblems; Inbound Vehicle Routing Problem with Makespan and Pickup, Line-haul Network Problem, and Outbound Vehicle Routing Problem with Delivery. In this paper, we propose 5 heuristic Algorithms; Selecting Routing Node, Routing Scheduling, Determining Vehicle Type with Number and Quantity, and Modification Selecting Routing Node. We apply these Algorithms to S vehicle company. The results of computational experiments demonstrate that proposed methods perform well and have better solutions than other methods considering the basic time and due-date.

토양 및 지형학적 특성에 따른 영산강유역의 소유역 분류 (Morphological Classification of Unit Basin on Soil & Geo-morphological Characteristics in Yeongsan River Basin)

  • 손연규;현병근;정석재;허승오;정강호;서명철;하상건
    • 한국수자원학회:학술대회논문집
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    • 한국수자원학회 2007년도 학술발표회 논문집
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    • pp.246-252
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    • 2007
  • 농업 비점오염원으로부터의 수질 보전이나 수자원 관리는 유역단위로 하여 농업적 관리뿐만 아니라 수질 관리 및 수자원 관리를 위해서도 유역단위 특히, 소유역의 토양특성을 포괄하는 단위로 체계적으로 분류할 필요성이 있다. 우리나라의 남서쪽에 위치한 영산강유역의 50개 소유역을 대상으로 토양도, 지형도, 하천도 및 유역도를 이용하여 만곡도, 산림의 비율, 평탄지의 비율, 다른 소유역으로부터의 유입이 있는지의 여부 등 토양학적으로 중요한 4개의 특성을 가지고 군집분석을 수행하였다. 그 결과 5개의 군으로 구분할 수 있었으며, 이 구분의 적합도를 검정하기 위하여 Mantel test를 한 결과 r = 0.81825로 나타나 적합하다는 결론을 얻었다. 이와 같이 토양과 지형특성을 포괄하는 소유역의 분류 및 유사성에 따른 그룹화는 농업에서의 최적영농관리나 오염물질에 따른 수질관리, 수문모형의 적용성 확대 및 수자원 관리에 합리적 유용성을 제공할 것이며 체계적 관리의 밑바탕이 될 것이다.

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정상 및 손상된 흰쥐 피부에 국소 적용된 $^{125}I-rhEGF$의 체내 이행 (Body Distribution of $^{125}I-rhEGF$ Across Normal and Damaged Rat Skins)

  • 이정욱;정석재;이민화;심창구
    • 약학회지
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    • 제41권6호
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    • pp.730-736
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    • 1997
  • Distribution of radioactivity in the skin tissues, subcutaneous tissues, blood and body organs was examined following topical application of $^{125}I-rhEGF$(0.4 ${\mu}Ci$), in the form of a Pluronic F-127 gel, on the normal and damaged (burned and stripped) skins of SD male rats. The radioactivity in the skin tissues and subcutaneous tissues was 3-5 times higher for the damaged skins than for the normal skin. But pretreatment of the skin with rhEGF (1${\mu}g$)) twice at 24 hr dose intervals affected the distribution of the radioactivity yielding the order of burned skin> stripped skin=normal skin. The decrease for the stripped skin by the pretreatment might be related either to the pathophysiological change of the skin or to the down regulation of the EGF receptor. Liver showed the highest radioactivity in amount following single and multiple administration of the drug to the normal and damaged skins. But,in concentration, the kidney and stomach showed higher value than the liver which is consistent with that kidney is a major eliminating organ of EGF and that EGF exerts its pharmacological effect specifically for the stomach.

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도심지의 지체 시간을 고려한 차량 경로 계획에 관한 연구 (Vehicle Routing Problem with Delay Time in the Downtown)

  • 윤태식;김경섭;정석재
    • 한국시뮬레이션학회논문지
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    • 제16권1호
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    • pp.39-47
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    • 2007
  • 도심지내 이동시 지점 간 속도는 시간대와 해당 지점에 따라 차이가 발생한다. 또한 두 지점 사이에는 수많은 신호대기와 병목 구간 등으로 인한 지체가 빈번히 발생한다. 이러한 지체 시간은 차량 경로를 계획함에 있어서 상당히 중요한 요소로 작용한다. 하지만 기존 차량 경로 문제 중 지점 간 이동 거리와 이동 시간에 초점을 맞춘 연구에서 지점 이동시 발생하는 지체에 대해서는 연구가 활발히 진행되지 않았다. 이에 본 연구에서는 지체 시간을 고려한 현실적인 차량 경로 문제에 접근한다. 이를 위해 신호 대기 간 발생하는 지체 시간과 병목 구간에서 발생하는 지체 시간을 추정하는 모델을 제시한다. 추정된 결과를 반영한 최적 차량 경로를 도출하여 지체 시간을 고려하지 않은 경로와 결과를 비교해 봄으로써 본 연구에서 제시하고 있는 방법이 우수하며 효율적임을 제시한다.

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