• 한국CDE학회논문집
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• 제2권1호
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• pp.1-10
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• 1997

Finding the optimum route of ship's pipes is complicated and time-consuming process. Experience of designers is the main tool in this process. To reduce design man-hours and human errors a design expert system shell and a geometric modeler is used to automate the design process. In this paper, a framework of the intelligent CAD system for pipe auto-routing is suggested, which consists of general-purpose expert system shell and a geometric modeler. The design expert system and the geometric modeling kernel have been integrated. The CADDS5 of Computervision is used as the overall CAD environment. The Nexpert Object of Neuron Data is used as the expert system shell. The CADDS5 ISSM is used as the interface that creates and modifies geometric models of pipes. Existing algorithms for the routing problem have been analyzed. Most of them are to solve the 2-D circuit routing problems. Ship piping system, specially within the engine room, is a complicated, large scale 3-D routing problem. Methods of expert system have been used to find the route of ship pipes on the main deck.

• 대한조선학회논문집
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• 제42권1호
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• pp.57-63
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• 2005

This paper introduces basic research of optimum routing assessment system as voyage support purpose which can obtain safe and efficient route. In view point of safety, the prediction of ship motion should be evaluated in the condition of rough weather This part includes general seakeeping estimation based on 3 dimensional panel method and parametric roil prediction. For increasing voyage efficiency, ETA(Estimated Time of Arrival) and fuel consumption should be calculated considering speed reduction and power increase due to wave effects based on added resistance calculation and ship performance characteristics. Basically, the weather forecast is assumed to be prepared previously to operate this system. The idea of these factors in this system will be helpful to escape from dangerous voyage situation by wave conditions and to make optimum route planning based on ETA and fuel consumption.

• 한국항해항만학회지
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• 제40권3호
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• pp.97-103
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• 2016

최적의 선박 운항 항로를 찾기 위해서는 선박의 정확한 추진성능을 추정하는 것이 매우 중요하다. 본 논문은 선박 최적운항시스템의 추진성능 데이터베이스를 생성하기 위한 전산프로그램의 개발에 대해 기술하고 있다. 실해역에서의 추진성능은 표류와 표면 거칠기 등 선체 상태뿐 만 아니라 파랑과 바람 등 해상 상태의 영향을 받는다. 이 부가저항 추정 방법들은 ISO 15016:2002 표준의 실선 속력시운전 해석법을 근간으로 하고 있으며, 추가로 바람과 선체 표면 거칠기에 대한 몇 가지 추정 방법이 보완되었다. 이 추정 방법들은 종합적인 전산프로그램으로 만들어졌다. 그리고 향후 최적 운항경로 계산에 활용될 쇄빙연구선 아라온 호에 대해서 데이터베이스 계산이 수행되었다. 이 프로그램은 모든 선박의 항로 최적화 계산에 유용하게 사용될 수 있을 것으로 판단된다.

• Management Science and Financial Engineering
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• 제11권2호
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• pp.45-60
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• 2005

This paper investigates the application of the computer method COMSOAL (Computer Method of Sequencing Operations for Assembly Lines) to the process routing (PR) problem with multiple objectives. In any computer aided process planning (CAPP) system, one of the most critical activities for manufacturing a part could be to generate the sequence that optimizes production time, production cost, machine utilization or with multiple these criteria. The COMSOAL has been adopted to find the optimum sequence of operations that optimizes two major conflicting criteria : production cost and production quality. The COMSOAL is here slightly modified to simultaneously generate and evaluate a set of possible solutions (called as population) instead of processing a solution stepwise in each iteration. The significant features of the COMSOAL include : no parameters settings needed, and a guarantee of feasible solutions. Experimental results show that COMSOAL is a simple but powerful method to quickly generate multiple feasible solutions which are as good as the ones obtained from several other well-known process routing algorithms.

• 경영과학
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• 제30권2호
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• pp.31-42
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• 2013

The vehicle routing problem (VRP) can be described as a problem to find the optimum traveling routes from one or several depot (s) to number of geographically scattered customers. This study executes a revised Heterogeneous Vehicle Routing Problem (HVRP) to minimize the cost that needs to conduct efficiently the snow removal operations of Air Wing under available resources and limited operations time. For this HVRP, we model the algorithm of an hybrid Ant Colony System (ACS). In the initial step for finding a solution, the modeled algorithm applies various alterations of a parameter that presents an amount of pheromone coming out from ants. This improvement of the initial solution illustrates to affect to derive better result ultimately. The purpose of this study proves that the algorithm using Hybrid heuristic incorporated in tabu and ACS develops the early studies to search best solution.

• Water Engineering Research
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• 제2권2호
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• pp.113-121
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• 2001

The objective of this study is to develop a prediction mode for a flood forecasting system in the downstream of the Nakdong river basin. Ranging from the gauging station at Jindong to the Nakdong estuary barrage, the hydraulic flood routing model(DWOPER) based on the Saint Venant equation was calibrated by comparing the calculated river stage with the observed river stages using four different flood events recorded. The upstream boundary condition was specified by the measured river stage data at Jindong station and the downstream boundary condition was given according to the tide level data observed at he Nakdong estuary barrage. The lateral inflow from tributaries were estimated by the rainfall-runoff model. In the calibration process, the optimum roughness coefficients for proper functions of channel reach and discharge were determined by minimizing the sum of the differences between the observed and the computed stage. In addition, the forecasting lead time on the basis of each gauging station was determined by a numerical simulation technique. Also, we suggested a model structure for a real-time flood forecasting system and tested it on the basis of past flood events. The testing results of the developed system showed close agreement between the forecasted and observed stages. Therefore, it is expected that the flood forecasting system we developed can improve the accuracy of flood forecasting on the Nakdong river.

• 대한교통학회지
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• 제22권5호
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• pp.89-97
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• 2004

현재 군 수송기는 매주 일정 대수가 각 기지 간 물자수송, 인원수송 그리고 조종사들의 훈련목적으로 정해진 스케줄에 의해 운항하고 있다. 일일 수송기 운행 경로는 모 기지에서 이륙하여 몇 개의 기지를 경유하여 임무를 수행한 후, 다시 모 기지로 돌아오는 패턴을 취하고 있다. 본 연구는 공군의 중앙물자를 저장하는 창에서 각 기지로 물자를 수송할 때 물량예측 및 적정노선에 대해서 시계열분석과 차량경로모형이라는 두 가지 방법을 통해 접근한다. 먼저 현재 공군에서 사용하고 있는 각종 규정과 교범상의 항공수송에 대한 제약사항 자료를 수집하여, 이를 바탕으로 본 연구에서는 다회방문이 가능하고, 경우회수에 대한 제약을 갖는 모형시과 알고리즘을 제안하였다. 또한 지난 몇 년간의 수송물량을 시계열 분석을 이용하여 예측하고, 예측된 수송소요를 제안된 알고리즘에 적용하여 적정노선을 계획하는 방법을 제안하였다. 제안된 모형과 알고리즘의 적합성과 경제성을 파악하기 위해 본 연구에서는 모형에서 계산된 수송물량과 필요 수송기 대수와 실제 공군에서 수행된 항공화물 수송 물량과 투입 수송기 대수를 비교함으로써 객관적인 모형의 우수성을 입증하고자 하였다.

• 대한교통학회지
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• 제23권4호
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• pp.81-91
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• 2005

외판원 문제(TSP; Traveling Salesman Problem)는 경로탐색 최적화문제로 '풀리지 않는 문제'(NP-complete; None-deterministic Polynomial-time complete)에 속하므로 경유지 수가 많아짐에 따라 급격히 계산시간이 증가한다. 때문에 적용시 정확한 최적해보다는 최적 근사해에 대한 발견적 (heuristic) 알고리즘들을 이용한다. 본 연구는 TSP에 적용되는 발견적 알고리즘으로 개미 시스템알고리즘(ASA; Ant System Algorithm)을 검토하고. 국내 택배시스템에 ASA의 적용가능성을 검토하였다. ASA는 NP-complete 문제를 위한 발견적 알고리즘으로, 1990년대 초 M. Dorigo 등에 의해 연구되어졌다. ASA는 개미들이 이동간에 페로몬이라는 일종의 화학물질을 분비할 때, 이동경로 상에 분비된 페로몬 누적에 따라 확률적 방법으로 경로를 결정하게 된다. 이러한 ASA는 NP-complete문제에서 계산시간이나 최단경로탐색에서 우수한 결과를 얻는 것으로 발표되고 있으며, 교통분야에서 차량경로탐색뿐만 아니라 네트워크 관리 및 도로선형계획 등 그 적용범위가 점차 확대되어지고 있다. 현재 국내 택배시스템에서 차량배차시 명확한 기준이 없으며 주로 담당 운전자의 경험과 판단에 의해 결정된다. 본 연구에서는 국내택배시스템에 ASA의 적용가능성을 검토하였다. 담당 운전자의 경로결정이 가로 10.0km, 세로 10.0km의 범위에서 인접이웃알고리즘(NNA: Nearest Neighbor Algorithm)을 따른다고 가정했을 때와 랜덤한 20개의 경유지를 가질 때, 그리고 경유지 수를 10개씩 증가하여 200개까지 증가할 때를 비교 분석한 결과, ASA이 NNA 보다 우수하였다. ASA을 국내택배시스템에 적용시 운송비용 절감 등의 운영개선을 기대할 수 있으며, 특히 영세한 택배업체에서 보다 저렴하고 우수한 택배시스템을 구축할 수 있을 것으로 보인다.

• 대한조선학회논문집
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• 제52권2호
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• pp.110-118
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• 2015

Weather routing method is one of the best practices of SEEMP (Ship Energy Efficiency Management Plan) for fuel-efficient operation of ship. KR is carrying out a basic research for development of the weather routing algorithm and making a monitoring system by FOC (Fuel Oil Consumption) analysis compared to the reference, which is the great circle route. The added resistances applied global sea/weather data can be calculated using ship data, and the results can be corrected to ship motions. The global sea/weather data such as significant wave height, ocean current and wind data can be used to calculate the added resistances. The reference route in a usual navigation is the great circle route, which is the shortest distance route. The global sea/weather data can be divided into grids, and the nearest grid data from a ship's position can be used to apply a ocean going vessel's sea conditions. Powell method is used as an optimized routing technique to minimize FOC considered sea/weather conditions, and FOC result can be compared with the great circle route result.

• 산업경영시스템학회지
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• 제35권1호
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• pp.140-147
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• 2012

Vehicle routing problem is one of the traveling salesman problems with various conditions such as vehicle capacity limits, delivery time windows, as well as time dependent speeds in metropolitan area. In this research hourly vehicle moving speeds information in a typical metropolitan area are analyzed to use the results in the design procedure of VRP heuristic. Quality initial vehicle routing solutions can be obtained with adaption of the analysed results of the time periods with no vehicle speed changes. This strategy makes complicated time dependent vehicle speed simple to solve. Time dependent vehicle speeds are too important to ignore to obtain optimum vehicle routing search for real life logistics systems.