• Journal of the military operations research society of Korea
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• v.33 no.1
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• pp.135-155
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• 2007

A performance specification states requirements in terms of the required results, such as performance, environment and interchangeability, but without stating the methods for achieving the required results, such as material and process. therefore the performance specification is applied to attain economic efficiency and high reliability by using the advanced commercial Technology for the weapon systems and The development of performance specification and conversion into performance specification have been activated in the advanced nations. The Ministry of National Defence of Korea has regulated the specification to make performance type in developing specification and prepared performance specification guide. but the result of the development of and conversion into performance specification is very unsatisfactory, To efficiently develop and convert into performance specification, this study gives the way of market research, the creation of the performance specification from development of weapon system and part localization, the process and method for conversion of detail specification into performance specification, the use of hybrid type of performance and detail specification.

• The Journal of Society for e-Business Studies
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• v.17 no.1
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• pp.91-110
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• 2012

Recently the effort of retailers improving the efficiency of store operations by using the information technology (IT) is increasing. Among them, the analysis of the shoppers' flow in retail stores is one of the critical tasks since it is an essential part in optimizing store layout and item grouping, and in developing the customized services specialized to shoppers' classification. Agent-Based Modeling and Simulation (ABMS) is one of the most promising methods which support analyzing the shoppers' flow. In this paper, we suggested a shopper's behavior model and developed an agent-based simulator for optimizing the operations of retail stores. In order to model the shoppers' behavior, we analyzed the behavioral characteristics of shoppers based on their shopping lists, suggesting BDI-based agent models of the shoppers' behavior. The shopping agent model were suggested, which has an additional mental state, the shopper's behavioral characteristic, as well as the original mental states of the BDI theory which has beliefs, desires and Intentions. The result of this study can be used in as a preliminary study for modeling and simulation of retail stores congestion and in the end the optimization of item grouping and store layout.

• Journal of the military operations research society of Korea
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• v.32 no.2
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• pp.78-91
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• 2006

Recently mass customization has become a new paradigm in the global market to satisfy both the diversified demands of customers but also the efficiency of the mass production system. In this paper, mass customization is embodied by a new product development method with which various product families are produced from standard "product platform" developed from historical data. The product platform, the key concept of this proposed method, is significantly efficient as a solution to the customer demand of high variety and small quantity products. The proposed method is applied to build the platform family of naval ships, utilizing the concept of "Group Technology". In addition, cost effectiveness of the proposed method is analyzed and the applicable range of requirement conditions are presented. In conclusion, some remarkable effects such as reduction in production cost and development time are expected by employing this method to the procurement process of the naval ships.

• Journal of the military operations research society of Korea
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• v.32 no.1
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• pp.51-72
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• 2006

There are many occasions that the performance of a corps is influenced not only by its own efforts but by the commander of the next higher unit in a vertical organizational structure. When the direction of the commander in the next higher organization is different from that of the actual evaluation agency, the unit under evaluation may get rated lower than what it should deserve. This study suggests an alternative method to evaluate the performance of military units in the situation that there exist critical environmental factors which affect the performance. This method employes DEA, a non parametric method, and Constrained Canonical Correlation Analysis(CCCA), a parametric method which is used to estimate a efficient frontier with multiple dependent variables and constraints. This article also exploits a set of categorical environmental variables in the CCCA to improve the fairness of performance evaluation. It is shown that the introduction of the categorical variables helps evaluating the true performance of individual units such as battalions subordinated to different next higher commanders.

• Journal of the Korea Society for Simulation
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• v.28 no.1
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• pp.57-65
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• 2019

Air refueling is expected to increase the efficiency of the air force operations. This follows from the introduction of air refueling aircraft, which should to increase operational time by increasing the range and duration of fighter jets. Despite the effectiveness of the air refueling air crafts, the astronomical costs of adapting the air tankers call for careful discussions on whether to acquire any air craft and if so, how many. However there is no academic study on the subject to our knowledge. Thus, we use the ABM(Agent Based Modeling) technique to calculate the optimal number of air tankers during patrol operation. We have enhanced the reliability of the simulation by entering the specifications of the current aircraft operated by the Korean Air Force. As an optimization tool for determining the optimal number of counts, we use OptQuest built into the simulation tools and show that the optimal number of air tanker is 4.

• Journal of Navigation and Port Research
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• v.46 no.1
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• pp.26-32
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• 2022

The port is a space where maritime transport and land transport intersect and is an essential industrial infrastructure for international trade. Therefore, it has a very important function in the national economy. Although the space and the physical facilities of a port are important, it is also very important to efficiently manage and operate these port infrastructures. The government introduced the Port Authority System to strengthen the efficiency and professionalism of port management operations. Since the port authority systemis based on port autonomy, the independence and autonomy of the port authority are very important in port management and operation. Nevertheless, the Port Authority is not functioning properly because the government interferes excessively with the operations of the Port Authority. Therefore, it is suggested that the legal system should be improved to strengthen the autonomy of the Port Authority (PA). This study examines the perception of the legal system that needs to be improved to strengthen the autonomy of the Port Authority, and suggests policy measures for Port Authority workers, civil servants, port companies, and civic groups.

• Journal of Korea Port Economic Association
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• v.37 no.3
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• pp.75-91
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• 2021

Due to increased competition in supply side to reduce operational costs, port professionals have experienced extreme pressure, which demanded academicians to develop the model for efficient port operations from the industry perspective. Among many ports in the world, U.S. ports are our primary interest to analyze in our study for its high volume of cargoes transacted in the U.S. ports. We primarily employed DEA (Data Envelopment Analysis) technique to research the productivity of U.S. ports and applied the algorithm of double bootstrapped DEA proposed by Simar & Wilson (2007) to further investigate the driving forces of the performance of U.S. port operations. The external variables employed in our study comprise onDock Rail, Channel Depth, Location, Area, Acres, ForeignCargoRatio, and TEUChange, out of which onDock Rail, Acres, ForeignCargoRatio, and TEUChange were significant. In order to evaluate the effects of methodology selection, we conducted the same analysis applying the Censored model (Tobit) and contrasted the outcomes drawn from the two different techniques. Based on the findings from this work we proposed managerial implications and concluded.

• Journal of the Korean Operations Research and Management Science Society
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• v.26 no.2
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• pp.99-109
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• 2001

In this study, we tried to build a model which can deal with the efficient and effective operation of electric power industry, especially focused on the nuclear industry. Here, SD (System Dynamics) approach is used to visualize the underlying phenomenon of the nuclear power industry. SD is a methodology for studying and managing complex feedback systems, such as one finds in business and other social systems. The spend of SD applications has grown extensively and now encompasses work in corporate planning and policy design, public management and policy, biological and medical modeling, energy and the environment. Recently, according to the report from KEPCO (Korea Electric Power Corporation), they are considering delaying a new power plant construction. It may be based upon business fluctuation downsized from Korean economic crisis in 1997 and freezing of construction funds due to unstable foreign exchange rate. At this point, we need disparately a kind of strategic model that would contribute to cope with the current business situation, energy generation, production, and resulting pollution. Specifically, this model, using SD approach, starts with the detailed drawing of influence diagram, which describes those relevant key points on nuclear power generation systems in electric power industry of Korea. These include such factors as the operation of nuclear industry and parameters related to the decision making for business policy. Based upon the above-mentioned influence diagram drawn, we developed SD simulation model to evaluate and analyze strategic management of KEPCO. Based on our analysis, we could demonstrate how simulation model can be applied to the real electric power generation in Korea.

• Spatial Information Research
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• v.8 no.1
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• pp.155-170
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• 2000

When we use R-Tree,a spatial index, to find objects matches some predicate, it often leads to an incorrect result of perform filtering step only with MBR. And , each candidates need to be inspected to conform if it really satisfies with given query, so called, 'refinement step'. In refinement step. we should perform disk I/O and expansive spatial operations which is the cause of increasing retrieval costs. Therefore, to minimize the number of candidate after filtering step, two-phase filtering methods were studied, but there was many problems such as inefficiency of filtering,maintenance of additional informations and reconstruction of data resulted from the loss of original information. So , in this paper, I propose an Extended R-Tree which provides ability to retrieve spatial objects only with some simple logical operations using Grid Table, truth table strong the information about the existence of spatial objects, in second filtering step. Consequently , this Extended R-Tree using Grid Filter has low cost of operation for filtering because of efficient second filtering step, and better filtering efficiency caused by high quality of approximation.

• Journal of Navigation and Port Research
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• v.38 no.6
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• pp.577-583
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• 2014

A ship-to-ship (STS) lightering operation takes place in order to transfer cargo (e.g. crude oil or petroleum products) between an ocean-going ship and a service ship alongside it. Instrumental measurements to accurately determine the relative speeds and distances during the approach between the vessels would benefit the operational safety and efficiency. A velocity information GPS (VI-GPS) system, which uses the instantaneous velocity measures from carrier-phase Doppler measurement, has been applied in a field observation onboard a service ship (Aframax tanker) approaching a ship-to-be-lightered (VLCC) in open waters. This article proposes to apply VI-GPS as the input sensor to a guidance and decision-support system aiming to provide accurate velocity information to the officer in charge of an STS operation. A method for precise velocity measurement using VI-GPS was described and the measurement results were compared each other with the results of Voyage Data Recorder (VDR) and VI-GPS that showed the concept of a guidance and decision-support system applying VI-GPS with the field test results during STS operations. Also, it turned out that VI-GPS has sufficient accuracy to serve as an input sensor from the field test results.