• 한국분말재료학회지
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• 제20권1호
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• pp.37-42
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• 2013

$YAG:Ce^{3+}$ phosphor powders were synthesized using a $Al_2O_3$ seed (average particle size: 5 ${\mu}m$) by the polymer solution route. PVA solution was added to the sol precursors consisting of the seed powder and metal nitrate salts for homogeneous mixing in atomic scale. All dried precursor gels were calcined at $500^{\circ}C$ and then heated at $1400^{\circ}C{\sim}1500^{\circ}C$ in $N_2/H_2$ atmosphere. The final powders were characterized by using XRD, SEM, PSA, PL and PKG test. All synthesized powders were crystallized to YAG phase without intermediate phases of YAM or YAP. The phosphor properties and morphologies of the synthesized powders were strongly dependent on the PVA content. Finally, the synthesized $YAG:Ce^{3+}$ phosphor powder heated at $1500^{\circ}C$, which is prepared from 12:1 PVA content and has an average particle size of 15 ${\mu}m$, showed similar phosphor properties to a commercial phosphor powder.

• 대한산업공학회지
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• 제23권4호
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• pp.645-660
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• 1997

An application of the genetic algorithm(GA) to the loading sequencing problem in port container terminals is presented in this paper. The efficiency of loading operations in port container terminals is highly dependent on the loading sequence of export containers. In order to sequence the loading operation, we hove to determine the route of each container handling equipment (transfer crane or straddle carried in the yard during the loading operation. The route of a container handling equipment is determined in a way of minimizing the total container handling time. An encoding method is developed which keeps intermediate solutions feasible and speeds up the evolution process. We determine the sequence of each individual container which the container handling equipment picks up at each yard-bay as well as the visiting sequence of yard-bays of the equipment during the loading operation. A numerical experiment is carried out to evaluate the performance of the algorithm developed.

• 한국항공운항학회지
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• 제25권3호
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• pp.51-60
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• 2017

Estimation of the taxi-out and taxi-in times of aircraft on a airport surface is one of the essential features of Departure Manager (DMAN). Especially for an airport with multiple runways and large ramp areas, estimation of the taxi-out and taxi-in times are mainly dependent on the taxi routes on airport surface. This paper described the method of automatic extraction of the the taxi routes using the ASDE track data and the Dijkstra algorithm based on the node-link model of a airport surface movements. In addition, we analyzed the ground operation status of Incheon International Airport using the extracted taxi routes.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2008년도 정보통신설비 학술대회
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• pp.177-180
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• 2008

There are many application areas of sensor networks, such as surveillance, hospital monitoring, and home network. These are dependent on the secure operation of networks, and will have serious outcome if the networks is injured. An adversary can inject false data into the network through the compromising node. Ye et al. proposed a statistical en-route filtering scheme (SEF) to detect such false data during forwarding process. In this scheme, it is important that the choice of the threshold value since it trades off security and overhead. This paper presents an adaptive threshold value determining method in the SEF using fuzzy logic. The fuzzy logic determines a security distance value by considering the situation of the network. The Sensor network is divided into several areas by the security distance value, it can each area to uses the different threshold value. The fuzzy based threshold value can reduce the energy consumption in transmitting.

• 한국항만경제학회지
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• 제30권1호
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• pp.143-157
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• 2014

미주나 구주항로의 서비스를 이용하는 수도권 화주 90%가 부산항을 이용하고 있다. 하지만 인천 신항의 항로수심이 -16m 이상으로 증심이 이루어진다면, 수도권 화주들의 항만선택행동에 큰 변화가 있을 것으로 예상된다. 이러한 측면에서 본 연구에서는 Logit모형을 이용하여 환경변화를 고려한 인천 신항의 수도권 화물의 분담률을 추정하는 것을 목적으로 하였다. 본 연구에서는 화주의 항만선택행동과 관련된 선행연구 고찰을 통해 정기선항로 항차 수(미주노선), 내륙운송운임, 컨테이너터미널 서비스 수준을 독립변수로 선정하고, 부산신항과 인천 신항을 더미화하여 종속변수로 활용한 효용함수를 구성하였다. 인천 신항과 부산신항이 갖는 총 효용치를 통해 현 수준에서 두 항만의 분담률을 분석한 결과, 기본 시나리오에서는 부산신항이 0.6618, 인천 신항이 0.3382라는 결과를 획득하였다.

• 대한산업공학회지
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• 제37권2호
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• pp.144-152
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• 2011

Most of the models for the vehicle routing problems studied in the literature assumed constant travel times. However, those approaches may give infeasible solutions when traffic congestion causes delays in travel time. To overcome such difficulty, there have been some researches considering the change of the travel time which is called the time dependent vehicle routing problem (TDVRP). TDVRP assumes that the travel time between two locations is not only affected by the distance traveled, but by many other factors including the time of the day. In this paper, we propose a branch-and-price algorithm to solve the TDVRP. The time dependent property of the travel time is dealt with an enumeration scheme with bounding procedures in the column generation procedure identifying a profitable route. The proposed algorithm guarantees the "Non-passing" property to be held in the solutions. The algorithm was tested on problems composed of the Solomon's benchmark instances for 25 and 50 nodes. Computational results are reported.

• 한국항행학회논문지
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• 제24권6호
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• pp.500-507
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• 2020

본 논문은 기록된 항적 데이터를 이용하여 혼잡한 공항의 비행 절차별 위험도를 분석하는 방법론을 제시하고, ADS-B (automatic dependent surveillance-broadcast) 데이터를 기반으로 재생성된 100일 치의 항적 데이터를 사용하여 인천국제공항과 김포국제공항의 비행 절차별 위험도를 분석한 결과를 보여준다. 위험도 분석은 DWC (detect and void well clear) 를 이용하였으며, 이를 통해 비행 절차별로 가장 높은 위험도가 나타나는 구간과 위험 발생이 잦은 구간을 평가하였다. 그 결과, 인천국제공항의 표준계기출발절차 중 RNAV BOPTA 1L의 SI712 - RANOS Fix 구간에서 가장 높은 위험도가 나타났으며, 표준계기도착절차 중에서는 RNAV GUKDO 1N에서는 SI947-DANAN Fix 구간에서 가장 높은 위험도가 나타났다. 또한 김포국제공항의 표준계기출발절차 중에서는 RNAV BULTI 1X의 SS726 - SS727 Fix, 표준계기도착절차 중에서는 RNAV OLMEN 1D의 KAKSO - KALMA Fix 구간에서 가장 높은 위험도가 나타났다.

• Spatial Information Research
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• 제17권3호
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• pp.361-370
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• 2009

최근 몇 년 사이 공간정보에 대한 관심이 증대됨에 따라 실내공간데이터 모델링 및 활용에 대한 많은 연구가 진행 되고 있다. 특히 대규모 실내공간에서 방재 알고리즘 및 실시간방재시스템에 대한 연구가 활발하게 진행 되고 있다. 재난 발생 시 요구될 수 있는 최적경로는 대피자를 위한 것과 구조자를 위한 것, 두 가지로 나뉠 수 있다. 본 연구에서는 구조자를 위한 최적경로를 산출하였는데 이는 실내의 어떠한 공간에서 출구까지의 경로가 아닌 출구에서 구조대상지역까지의 경로를 의미한다. 실시간 방재시스템에 적합한 최적경로는 시간에 대해 가변적이어야 한다. 이러한 최적경로를 산출하기 위해서는 최적경로 산출에 필요한 시간에 따라 변화하는 변수가 고려되어야 한다. 즉, 복도 또는 방과 같은 공간의 수용능력 및 흐름정도 등을 포함하는 동적인 공간적 엔티티를 관리 할 수 있는 시공간 데이터베이스와 연동되어 있어야 한다. 공간상에서 동적객체의 흐름을 측정하고 분석을 통해 추정한 시공간 데이터베이스는 최적경로 산출과 대피상황에서의 병목현상 예측에 사용될 수 있다. 본 연구에서는 실시간 방재시스템 개발을 위한 시공간 데이터를 적용한 최적경로 산출 알고리즘을 제시하였다. 제안된 알고리즘을 테스트하기 위하여 건물 내부의 이동이 가능한 공간을 표현하는 네트워크데이터를 사용하였다.

• Archives of Pharmacal Research
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• 제14권2호
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• pp.188-192
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• 1991

Single non-lethal doses of chloroform $(CHCL_3)$ dichlorobromomethane $(CHCL_2Br)$, dibromochloromethane $(CHCIBr_2)$, or bromoform $(CHBr_3)$ were administered to male rats. Routes of exposure including single intraperitional (ip) and subcutaneous (sc) injection were used in order to permit comparison of severity of THM effects and renal toxicity was assessed at varied times following treatment. On an equimolar basis, sc administration of $CHBr_3$ (either 12 or 3 mmoles/kg) is more effective at increasing KW/BW than ip $CHCI_3$ treatment. Plasma urea nitrogen (BUN) following ip THM injections are markedly increased with all four THM at 24 hours post treatment. BUN response to $CHCL_2Br$ and $CHCIBr_3$-effected BUN levels have essentially returned to those of vehicle control. THM sc treatment results in a BUN response similar to that seen following ip treatment, with only the time course being different. With the exception of $CHCL_3$, sc and ip-treatments appear to be equally effective in evoking absolute BUN elevations. These results suggest that THM administration induce renal toxicity dependent upon the route or exposure.

• Strategy21
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• 통권30호
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• pp.200-235
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• 2012

Over the past few years, due to the climate change of the earth, the Arctic's sea ice cover is undergoing a historic transformation - thinning, extent reduction in all seasons, and mitigation in the area of multi-year ice in the central Arctic Ocean. These changes allow for increases in maritime access throughout the Arctic Ocean and for potential longer seasons of navigation and possibly transarctic voyage in the summer. These changes also allow more exploration for oil, gas, and other minerals. The Arctic is now an archetype of the complex, multi-dimensional global problems of the twenty-first century. Military security, environmental security, and economic security interact. The potentially enormous economic stakes, sufficient to change the strategic balance among the states of the region, set off competitive pressures for national advantage. Korea, which is heavily dependent upon the sea lane in terms of transportation of its exports and imports, is very much interested in the Arctic sea routes. Korea believes that the Artic sea route, particularly the Northern Sea Route (NSR), could serve as a new useful sea lane, which will enable shorter times between East Asia and Europe, thus resulting in substantial cost saving for ship operators. In addition to shipping, Korea is interested in other Arctic-related maritime industries. Korea, as a leading shipbuilder in the global market, is interested in building ice breakers, drill ships, and other vessels which can contribute to safe operation in Arctic resource development and exploration. Korea, as one of the future stakeholders in Arctic maritime activities, should be ready to foster international cooperation in the region.