The study analyzes those relations of customer service level of each sales branch, level of cooperations among branches, and overall system-wide service level for an item. Under the continuous review method, each sales branch places an order to the outside supplier, and the each branch receives the order quantity after elapsing a certain lead time. Under these circumstances, those branches with stockout condition may be supplied by other branches with keeping stocks to cover the shortages. This policy generally increases the system-wide customer service level for an item throughout cooperations for the safety plan among branches. Therefore, in the context of inventory policy, the decision rules to determine the proper branch levels of service and cooperation levels of service are important goals in terms of attaining desired system-wide service level. This research has suggested the method and procedure to reach above goals.

This research fundamentally deals with an analysis of service level for a multi-level inventory distribution system which is consisted of a central distribution center and several branches being supplied stocks from the distribution center, Under continuous review policy, the distribution center places an order for planned order quantity to an outside supplier, and the order quantity is received after a certain lead time. Also, each branch places an order for particular quantity to its distribution center, and receives the order quantity after a lead time. In most practical distribution environment, demands and lead times are generally not fixed or constant, but variable. And these variabilities make the analysis more complicated. Thus, the main objective of this research is to suggest a method to compute the service level at each depot, that is, the distribution center and each branch with variable demands and variable lead times. Further, the model will give an idea to keep the proper level of safety stocks that can attain effective or expected service level for each depot

In this research, the system is assumed to carry a single item of which the demand types vary. Demand type is defined as a management's classification of the item according to the demand source or to the service purpose. The purpose of this research is to find the optimal inventory control policy when the system carries a single item which consists of multiple demand types. In this research, the optimizing algorithm contains a heuristic, therefore, the optimal Is not guaranteed by the algorithm. At least, this research provides the solution to the problems that have not been solved by the existing algorithms.

In this research, the system is assumed to carry a single item of which the demand types vary. Demand type is defined as a management's classification of the item according to the demand source or to the service purpose. The purpose of this research is to find the optimal inventory control policy when the system carries a single item which consists of multiple demand types. In this research, the optimizing algorithm contains a heuristic, therefore, the optimal is not guaranteed by the algorithm. At least, this research provides the solution to the problems that have not been solved by the existing algorithms.

In this study, the writer embodies factors influencing on ship safety management by an empirical survey. In the empirical survey, the writer used a questionnaire. 1, 271 proper data was obtained from 4, 240 Korean seamen working in 152 domestic and 60 foreign merchant ships. Reliability was tested by Cronbach's Alpha and a conceptual validity by Factor Analysis. Hypotheses established in this study were tested by Correlation and Multiple Regression Analysis. Results of analysis are as follows: Firstly, three levels(i.e. planning, doing, and evaluation) of safety management and satisfaction level of shipboard life correlate significantly with level of ship safety management and between them(P<0.05) Secondly, satisfaction level of shipboard life, evaluation and planning levels of safety management influence significantly on level of ship safety management(P<0.05).