• Journal of the Society of Naval Architects of Korea
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• v.47 no.2
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• pp.122-131
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• 2010

The increasing size and speed of cargo ships result in high speed flow in propeller slipstream, and thereby cavitation is frequently observed on and around a rudder system. Rudder gap cavitation is the most difficult one to control and suppress among various types of the cavitation on a rudder system. In the present study, experiments of the incipient cavitation and pressure measurement were carried out for typical cargo ship rudder sections with and without the suppression devices, which were suggested by the authors. Fundamental understanding of the rudder gap cavitation inception was obtained along with its relevance to the surface pressure distribution. It is confirmed that the gap flow blocking devices effectively suppress the rudder gap cavitation and, at the same time, augment lift.

• Korean Management Science Review
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• v.30 no.1
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• pp.125-137
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• 2013

The U.S. Army is capable and ready to deploy full-spectrum armed forces anywhere in the world as we have seen in Iraq and Afghanistan. This commitment is within the realm of logistics support that the readiness to support MRE(Meal Ready to Eat), according to the environment where the operation is on going. ROKA(Republic Of Korea Army) proceeds with the program to develop and reserve various MRE under the assumption of distinctive warfare operating environment. This study investigates to determine the amount of MRE consumption within various operating environment and details are as follows. First we ponder the concept of MRE and identified problems of the existing program. Second we also establish feeding rations by the types of MRE that is the base for calculation. Third we introduce MRE consumption algorithm and formula. Fourth and last we have applied our model to the program and analyzed the results. The present state of the estimation didn't reflect various warfare operating environment. Therefore we simulates theater wargame model to determine the consumption under various warfare operating environment. The result of this study is anticipated to contribute largely to the force enhancement as it mirrors of every circumstances of operating environment.

• The Journal of Asian Finance, Economics and Business
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• v.1 no.4
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• pp.15-21
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• 2014

The main purpose of the research is to suggest a new business model of direct distribution of organic agricultural products cultivated in suburban area. To secure competitiveness, logistics cost reduction is important through direct transaction of organic agricultural products cultivated on suburban area. The research addresses food safety, farmers' income and unemployment issues with Eco-M business model. The research methods include investigation on the followings: current domestic agriculture; related problems on the existing literature reviews; the current status of suburban agriculture; specialty store of eco-friendly agricultural products. Eco-M business model can solve various problems of suburban agriculture supply system, challenges of organic farming specialty stores, unemployment issues, and difficulties of processing verticalization. Future research should include followings. First, there should be comparative analysis between businesses of environment-friendly specialty stores through suburban agriculture and producer's agriculture connected with organic farming market. Second, it is required to develop strategy of environment-friendly specialty stores. Finally, analysis of the potential of Sextic industries is necessary throughout production-process-service process.

• Journal of Information Processing Systems
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• v.15 no.6
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• pp.1422-1437
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• 2019

With the rapid development of the Internet and the Mobile Internet, social communication based on the network has become a life style for many people. WeChat is an online social platform, for about one billion users, therefore, it is meaningful to study the spreading and evolution mechanism of the rumor on the WeChat social circle. The Rumor was injected into the WeChat social circle by certain individuals, and the communication and the evolution occur among the nodes within the circle; after the refuting-rumor-information injected into the circle, subsequently,the density of four types of nodes, including the Susceptible, the Latent, the Infective, and the Recovery changes, which results in evolving the WeChat social circle system. In the study, the evolution characteristics of the four node types are analyzed, through construction of the evolution equation. The evolution process of the rumor injection and the refuting-rumor-information injection is simulated through the structure of the virtual social network, and the evolution laws of the four states are depicted by figures. The significant results from this study suggest that the spreading and evolving of the rumors are closely related to the nodes degree on the WeChat social circle.

• Korean Journal of Computational Design and Engineering
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• v.14 no.3
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• pp.186-196
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• 2009

Mass customization (MC) is a business practice that aims to provide customers with customized products and services at near mass production efficiency. To achieve the aim, a number of methods to implementing MC are proposed. However, most of them require changes in entire process of the company, which make companies hesitate to implement MC even if it is essential to survive. In this paper, we proposed alternatives to partially implement MC for quick adaptation of MC. The base line assumption is not to change the production lines. The pros and cons of alternatives are given by qualitative and quantitative evaluation. Especially, by giving radar chart analysis of the quantitative measures, we give insight on the changes in the business performance measures, such as time to market and cost. Proposed alternatives are based on sub-processes such as purchasing raw materials, production process changes and packaging for efficient logistics. In this way, companies are able to provide customized products with small changing of the current manufacturing system. The process and benefit of the proposed strategy is verified by real world cases of a Korean health food company.

• Convergence Security Journal
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• v.16 no.3_2
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• pp.25-32
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• 2016

Drone refers to an unmanned flying system according to the remote control. That is a remote control systems on the ground or a system that automatically or semi auto-piloted system without pilot on board. Drones have been used and developed before for military purposes. However there are currently utilized in a variety of areas such as logistics and distribution of relief supplies disaster areas, wireless Internet connection, TV, video shooting and disaster observation, tracking criminals etc. Especially it can be actively used in activities such as search or the structure of the disaster site, and may be able to detect the movement of people and an attacker using an infrared camera at night. Drones are very effective for private security.

• Journal of Navigation and Port Research
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• v.33 no.5
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• pp.331-337
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• 2009

Container crane is main equipment in container terminals and it determines the productivity and the efficiency of container terminals. The typical type of container cranes has the single trolley and one among advanced types of them has the dual trolley. The objective of this paper is to analyze the buffer size of a container crane with the dual trolley in container terminals. We present a simulation model for analysing the buffer space of a container crane with the dual trolley. The buffer space is located between main trolley in sea-side and second trolley in yard-side. We performs various simulation experiments and analyze the buffer size to estimate the required productivity.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.10a
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• pp.251-252
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• 2015

Recently, as warehouses became automated, workers are trying to maximize storage efficiency as well as work efficiency. So, using mobile-rack which has wheels or rails at the bottom and minimizes dead space by removing extra passages between racks is rapidly rising as a notable technology. So, this paper seeks how to manage optimally cryogenic warehouse using mobile-rack. At first, routes of mobile-rack and operation vehicle will be synchronized and storage location will be decided with seasonal demand. After that, it will be simulated considering additional factors.

• IE interfaces
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• v.23 no.4
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• pp.349-356
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• 2010

The role of Intelligent Transportation System (ITS) is to efficiently manipulate the traffic flow and reduce the cost in logistics by using the state of the art technologies which combine telecommunication, sensor, and control technology. Especially, the hardware part of ITS is rapidly adapting to the up-to-date techniques in GPS and telematics to provide essential raw data to the controllers. However, the software part of ITS needs more sophisticated techniques to take care of vast amount of on-line data to be analyzed by the controller for their decision makings. In this paper, the authors develop a traffic congestion prediction model based on several different parameters from the sensory data captured in the Vehicle Detection System (VDS). This model uses the neural network technology in analyzing the traffic flow and predicting the traffic congestion in the designated area. This model also validates the results by analyzing the errors between actual traffic data and prediction program.

• IE interfaces
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• v.20 no.4
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• pp.469-478
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• 2007

Rail transportation terminals play an important role in inland transportation systems, because the operation productivity in the terminals significantly influences the efficiency of the whole transportation systems. This paper addresses a design method of a real rail terminal that satisfies a pre-specified throughput capacity. In order to construct high performance rail terminal, it is shown how design parameters can be estimated systematically. Examples of the design parameters are the number of transshipment tracks, the number of rail cranes, and the number of internal trucks. These design parameters are estimated by using simple equations and the validity of the values of these parameters are tested by using simulation. Furthermore, some iterative correction procedure, which uses the simulation technique and the equations alternately, are proposed.