• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2008년도 추계학술대회 및 정기총회
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• pp.290-296
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• 2008

This paper considers a two-stage dynamic lot-sizing problem constrained by a supplier's production capacity. We derive an improved O($T^6$) algorithm over the O($T^7$) algorithm in van Hoesel et al. (2005).

• 대한산업공학회지
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• 제36권1호
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• pp.7-12
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• 2010

This paper considers a dynamic lot-sizing problem with backlogging under a minimum replenishment policy. For general concave production costs, we propose an O($T^5$) dynamic programming algorithm. If speculative motive is not allowed, in this case, a more efficient O($T^4$) algorithm is developed.

• KSBB Journal
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• 제8권2호
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• pp.150-155
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• 1993

난분해성인 색소를 대사분해할 수 있는 미생물을 분리하여, 색소분해의 최적조건을 조사하였다. 미생물은 폐수처리공장의 폭기조에서 채취한 폐수로부터 agar media에서 순수분리하였다. 이 균주들을 glu­c cose, peptone, $Na_2HPO_45, KCI, MgSO_4, KH_2PO_4, NaCI, CaCI_2$와 dye(azo계, reactive red계 ) lOppm 을 함유한 액체 배지에서 dye의 분해력이 강하였으 며, 이때의 최적 pH는 중성 또는 약알칼리성이고, 최적 온도는 $30^{\circ}C$ 전후이다. 이 조건에서 10ppm의 m mono-azo(Lot No. 180), di-azo(Lot No. 138), re­a active red(Lot No.2)는 약 2일에 거의 분해되었고, di-azo(Lot No. 151), reactive red(Lot No. 34, L Lot No. 00166)는 약 5일에 거의 분해되었고, 최적 배지조건하에서 산소의 영향은 D.O를 50%로 유지 시켰을 경우보다 혐기성 배양의 경우가 reactive d dye(Lot No.2)의 분해도가 훨씬 높았다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 춘계 학술논문 발표대회
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• pp.262-263
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• 2014

The purpose of this study was to investigate properties of high fluidity concrete adding waste marble powder. A change in the replacement ratios of waste marble powder was measured compressive strength and slump flow, O-Lot and U-Box. Waste marble powder has replaced binder of high fluidity concrete at certain contents of 0~20%. As a results, Slump flow, O-Lot and U-box adding waste marble powder up to 10% have increased by adding waste marble powder. As the concrete with a replacement ratio of waste marble powder up to 10% was found to have a compressive strength superior to that of plain.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2006년도 춘계공동학술대회 논문집
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• pp.133-136
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• 2006

We consider dynamic lot-sizing model with production time windows where each of n demands has earliest due date and latest due date and it must be satisfied during the given time window. For the case of nonspeculative cost structure, an O(nlog n) time procedure is developed and it is shown to run in O(n) when demands come in the order of latest due dates.

• 대한인간공학회지
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• 제34권5호
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• pp.427-436
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• 2015

Objective: This study aims to analyze occupational accidents of parking lot attendants by parking lot type. Background: Recently, efforts are made to analyze accident characteristics by occupation type targeting the workers engaged in the same work. Method: This study analyzes 303 occupational accidents of parking lot attendants occurring from 2010 to 2012. Parking lots are grouped into two groups according to the work environment. One is public/ground type which comprises road side or open area parking lots and the other is building/mechanical type which comprises a multi-story parking building with connecting ramps and/or mechanical parking system. The characteristics of occupational accidents by parking lot type are analyzed. Results: Accident characteristics showed the difference between public/ground type and building/mechanical type on the size of enterprise, age, gender and work experience of the injured. Also the accident type, source of accident and parts of body affected are different between the two parking lot types. Conclusion and Application: The findings of accident characteristics according to parking lot types can be used as baseline data for establishing systemized preventative policies for occupational accidents of parking lot attendants.

• 한국컴퓨터정보학회논문지
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• 제19권12호
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• pp.171-175
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• 2014

NP-완전인 상자 포장 문제의 일종인 사탕수수 설탕 생산 문제에 대해, Gu$\acute{e}$ret et al.은 $O(m^4)$ 수행 복잡도의 선형계획법으로 해를 얻고자 하였다. 반면에, 본 논문에서는 사탕수수 설탕 생산 문제는 다항시간으로 해를 찾아가는 규칙이 존재한다는 가정하에, 최대 손실량을 가진 로트를 우선 생산하는 탐욕 규칙인 O(mlogm)의 다항시간 복잡도로 해를 구할 수 있는 알고리즘을 제안하였다. 제안된 방법은 설탕 함유량 손실 기울기를 내림차순으로 정렬한 후, 해당 슬롯 생산능력의 로트들을 선택하는 방법과 해당 슬롯에서 수명을 다하는 로트들과 마지막으로 선택된 로트들과 교환하는 방법을 적용하였다. 실험 결과, 제안된 알고리즘은 사탕수수 설탕 생산 문제에 대해 선형계획법의 $O(m^4)$를 O(mlogm) 으로 단축시키면서도 보다 좋은 결과를 얻었다.

• 한국인터넷방송통신학회논문지
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• 제21권2호
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• pp.169-175
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• 2021

로트 크기 문제(LSP)는 다항시간으로 최적 해를 찾을 수 있는 알고리즘이 알려져 있지 않은 NP-완전의 난제이다. LSP에 대해 다항시간으로 해를 구할 수 있는 W-W 알고리즘이 알려져 있지만, 이 알고리즘은 너무나 복잡하여 이해와 적용에 어려움이 있어 S-M의 휴리스틱 근사 알고리즘이 제안되었다. 본 논문에서는 LSP의 근사 해가 아닌 최적 해를 찾을 수 있는 간단한 공식을 가진 O(n)의 선형 복잡도 알고리즘을 제안하였다. 제안된 알고리즘은 t시점에서의 로트 크기(생산량) Xt∗은 비축 비가 절차 비를 초과하지 않는 t+k 시점을 결정하여 [t,t+k] 구간의 요구량 합으로 단순히 결정하였다. 제안된 알고리즘을 다양한 실험 데이터에 적용한 결과 모든 데이터에 대해 최적 해를 찾았다.

• 한국주조공학회지
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• 제11권4호
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• pp.293-302
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• 1991

Aluminum alloy matrix composites reinforced with various amounts of $Al_2O_3$ short fibers have been produced by a combined technique of rheo-compocasting and hot extrusion. Distribution of fibers in the composites fabricated by rheo-compocasting was relatively uniform. A good degree of uniaxial fiber alignment has been achieved by hot extrusion, but a lot of fibers fractured during extrusion. The tendency of fiber fracturing increases as the aspect ratio and the amount of fibers increase. Relatively good bonding between fiber and matrix was obtained by the formation of $MgAl_2O_4$ and Mg(Al, Fe)$_2O_4$ at the interface between fiber and matrix. In extruded composites, fiber-strengthening effect was relatively small since a lot of fibers fractured during hot extrusion. On the other hand, dispersion strengthening effect may increase. In order to improve the fiber strengthening effect, it is important to optimize the extrusion condition with consideration of metal flow in extrusion die.

• 동력기계공학회지
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• 제20권5호
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• pp.20-28
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• 2016

This study has developed an organic/inorganic hybrid solution by addition of $SiO_2$ polysilicate and Melamine to the urethane. The three types of cold rolled steel were evaluated a corrosion resistance properties by using these solutions. The urethane solution(U) and the urethane solution with $SiO_2$ polysilicate($US_7$) were generate a lot of corrosion. The urethane solution with $SiO_2$ polysilicate and melamine($US_7M_3$) was excellent in corrosion resistance, regardless of the steel type. In addition, corrosion resistance has been shown to depend on the tensile strength. The appearance of coating by U and $US_7$ solution is bumpy surface, and were a lot of fine defects. $US_7M_3$ solution is made a sophisticated molecular cross-linking structure inside the coating, it was a slick surface. Other characteristics are exhibited the excellent property for all solutions.