화주 직접운항 선대의 운영 최적화 분석

김시화,이경근 한국경영과학회 1998 韓國經營科學會誌 Vol.23 No.4

The Industrial operation is one of the three basic modes of shipping operation with Liner and Tramp operations. Industrial operators usually control vessels of their own or on a time charter to minimize the cost of shipping their cargoes. Such operations abound in shipping of bulk commodities, such as oil, chemicals and ores. This work is concerned with an operational optimization analysis of the fleet owned by a major oil company. a typical Industrial operator. The operational optimization problem of the fleet of a major oil company is divided into two phase problem. The front end corresponds to the optimization problem of the transportation of crude oil. product mix. and the optimization problem of the fleet to meet the seaborne transportation demand derived from the front end. A case study reflecting the practices of an international major oil company is demonstrated to make clear the underlving ideas.

승선근무예비역 병역제도의 정착과 향후 대책

김시화 대한민국해양연맹 2007 해양정책 심포지엄 Vol.2007 No.1

Shading Coil의 최적 회로정수 결정에 관한 연구

김시화 한국항해항만학회 1985 한국항해학회지 Vol.9 No.1

It has been generally known that the chattering of an AC electromagnetic contactor due to the fluctuation of attracting force is the primary cause of its abrasion and noise. To reduce this chattering effect, an AC electromagnetic contactor is mostly fitted with a shading coil which works the role to make difference in phases of two distinct components of attracting force. The theoretical interpretation of an AC electromagnetic contactor with shading coil and the equation of its attracting force per unit wattage consumed have already been proposed, however, few explications so far have been made on the determination of optimal circuit constants of shading coil. In this paper, the auther constructs a circuit model of an AC electromagnetic contactor with shading coil which is based on the theoretical interpretation of shading coil examined to be valid by experiments under some assumptions, and defines the equation of attracting force without chattering per unit wattage consumed as a performance function for determining the optimal circuit constants of shading coil. And then, the optimal circuit constants maximizing the performance function are determined by means of computer simulation founded on the above circuit model and the characteristics of those circuit constants are examined with special attention to the coupling coefficient.

해운 및 항만운송에 적용된 의사결정분석에 관한 연구

김시화 한국항해항만학회 1988 한국항해학회지 Vol.12 No.1

Decision Science or Decision Analysis can be described as a scientific methodolog to provide suitable quantitative information for the decision maker to be able to selected the best feasible alternative on the given decision environment and thus we can say that where there are decision problems, there needs the decision analysis to be applied to them. International shipping is generally said to be the cheapest and most widely used means of transport in international trade and each of the hundreds of seaport. So far as the decision makings in the shipping and port transportation are concerned, of real importance is to understand what the decision problems in each of shipping and port transportation really are and to recognize the meaning of relevance between shipping and seaport in the outworn phrase, that is to say, "The chain is as strong as its weakest link." This paper is intended to present a literature survey on the applied decision analysis to shipping and port transportation problems which have actually been involved in the wide variety of decision environment. At first, the author suggests four divisional framework such as decision analysis in each field of Shipping Economics, Management and Operations of Shipping, Port Economics, and Port Operation and Management, according to the main concern of the decision environment, and then the literature surveys on those four major divisions are described including the problems and solution approaches in each case. The author concludes the paper with the comment on the need of joint research around this area by citing the phrase of "a process of updating the decision makers' intuitions."s' intuitions."quot;

Shading Coil이 장치된 전자개폐기의 흡인력에 관한 연구

김시화,노창주 한국항해항만학회 1982 한국항해학회지 Vol.6 No.2

The attempt of this paper is to examine the basic theory on the analysis of the effect of a shading coil fitted to an electromagnetic contactor, and to compare experimentally the attracting force of an AC electromagnetic contactor with that of a DC electromagnetic contactor, with varying the airgap length. Equations are also proposed for calculating the AC and DC attracting force per unit consumption wattage by using the circuit constants measured from the experiment, and these calculated attracting forces are compared with those actulally measured, and then, the experimental contactor is examined in the view of its design. The calculated attracting forces are appeared to coincide well with the measured ones and the experimental contactor fitted with shading coil is revealed not so well designed for reducing the fluctuation of the attracting force.

자동화선의 평균예상전문가시스템 개발에 관한 연구

김시화 한국항해항만학회 1991 한국항해학회지 Vol.15 No.2

This paper intends to develop a Prototype Expert Collision Avoidance System by introducing expert system techniques into the decision block of anti-collision loop. The problem domain of this study is characterized and specified by combining the concepts of anti-collision loop and knowledge -based system for collision avoidance. Domain in knowledge which may originates from the appropriate sources such as the International Regulations for Preventing Collision at Sea 1972, Marine Traffic Laws, and many texts on the subject of anticollision navigation and good seamanship is acquired and formalized into the knowledge-base system using production rule. Finally, a Prototype Expert Collision Avoidance System is built by using the CLIPS, developed by AIS NASA written in and fully integrated with the C language, and some test-and-run results of the system are demonstrated and examined. The author considers the proposed system which is named PECAS to be meaningful as a test bed for a further refined Expert Collision Avoidance System on board the Automated Ship.

인더스트리얼 캐리어를 위한 통합 선대관리 지원시스템

김시화,허강이 한국항해항만학회 1999 한국항해학회지 Vol.23 No.4

This paper aims at developing an integrated fleet management support system for industrial carriers who usually control the vessels of their own or on a time charter to minimize the cost of shipping their cargoes. The work is mainly concerned with the operational management problem of the fleet owned by a major oil company, a typical industrial carrier. The optimal fleet management problem for the major oil company can be divided into two phase problem. The front end corresponds to the production operation problem of the transportation of crude oil, the refinery operation, and the distribution of product oil to comply with the demand of the market. The back end is to tackle the fleet scheduling problem to meet the seaborne transportation demand derived from the front end. Relevant optimization models for each phase are proposed and described briefly. Then a user-friendly integrated fleet management support system is built based on the proposed optimization models for both ends under Windows environment. A case study reflecting the practices of fleet management problem for the major oil company is carried out by using the system.

인더스트리얼 캐리어를 위한 선대운영의 최적화에 관한 연구

김시화,곽민석 한국항해항만학회 1998 한국항해학회지 Vol.22 No.4

There are three basic modes of operation of ships: liner, tramp and industrial operations. Industrial operations, where the owner of the cargo, i.e. the industrial carrier controls the ships, abound in the shipment of bulk commodities, such as oil, chemicals and ores. Industrial carriers strive to minimize the shipping cost of their cargoes. This paper is concerned with the operational optimization problem of a fleet owned by major international oil company. The major oil company is a holding corporation for a group of oil producing, transporting, refining, and marketing companies located in various countries throughout the world. The operational optimization problem of the fleet is divided into two-phases. The front end corresponds to the optimization of transporting crude oil, product mix, and the distribution of product oil to meet market demand. The back end tackles the operational optimization problem of the fleet to meet the transportation demand derived from the front end. A case study is carried out with the H major oil company problem composed by reflecting the practices of an international major oil company. The results are summarized and examined in the point of optimization for the total operation of the H major oil company and the operational optimization problem of the fleet. The paper concludes with the remark that the results of the study might be useful and applicable in practices of these related decision problems.

유조선 운항 일정계획 의사결정 지원시스템의 개발에 관한 연구

김시화,이희용 한국항해항만학회 1996 한국항해학회지 Vol.20 No.1

Vessles in the world merchant fleet generally operate in either liner or bulk trade. The supply and the demand trend of general cargo ship are both on the ebb, however, those trend of tankers and containers are in slight ascension. Oil tankers are so far the largest single vessel type in the world fleet and the tanker market is often cited as a textbook example of perfect competition. Some shipping statistics in recent years show that there has been a radical fluctuation in spot charter rate under easy charterer's market. This implys that the proper scheduling of tankers under spot market fluctuation has the great potential of improving the owner's profit and economic performance of shipping. This paper aims at developing the TS-DSS(Decision Support System for Tanker Scheduling) in the context of the importance of scheduling decisions. The TS-DSS is defined as the DSS based on the optimization models for tanker scheduling. The system has been developed through the life cycle of systems analysis, design, and implementation to be user-friendly system. The performance of the system has been tested and examined by using the data edited under several tanker scheduling scenarios and thereby the effectiveness of TS-DSS is validated satifactorily. The authors conclude the paper with the comments on the need of appropriate support environment such as data-based DSS and network system for succesful implementation of the TS-DSS.

선석할당 계획문제의 최적화에 관한 연구

김시화,김대상 한국항해항만학회 2001 한국항해학회지 Vol.25 No.1

이 논문은 공공 컨테이너 터미널에서 직면하는 선석할당 계획문제를 다루고 있다. 선석할당 계획문제의 주된 논점은 ETA가 주어진 컨데이너 선박들을 어떻게 선석에 할당할 것인가를 결정하는 것이다. 선석할당 계획문제의 세 가지 최적화 모형들은 집합 문제 유형으로 정식화시켜 제시하였다. 또한, 제안된 최적화 모형의 의사결정 변수를 생성하기 위한 경험론적 알고리듬은 선박의 대기시간과 선석 점유율을 사용하여 고안하였다. 계산 실험은 실제 공공 컨데이너 터미널의 데이터로 수행하였으며, 그 결과들은 제안된 최적화 모형들과 경험론적 알고리듬들이 공공 컨테이너 터미널의 선석할당 계획문제에 대하여 유용하게 적용될 수 있음을 제시하고 있다. This paper treats the berth planning problem which is encountered at public container terminals. The main issue of the berth planning problem is to decide how to allocate the berths to scheduled calling containerships of which the ETA' s are given beforehand. Three optimization models for the berth planning problem are proposed in the formulation of set problems. Some heuristic algorithms for generating the decision variables of the models are also devised by using the concept of the ship's waiting time and the modified berth occupancy rate. Computational experiments based on the data arising from the real public container terminal are also carried out and the results are reported to show that the proposed optimization models and the heuristic algorithms for generating the decision variables are applicable and useful for the berth planning problem at public container terminals.