• Journal of Korea Multimedia Society
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• v.12 no.6
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• pp.824-832
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• 2009

Multi-radio multi-channel Wireless Mesh Network requires an effective management policy to control the assignment of channels to each radio. We concentrated our investigation on modeling method and solution to find a dynamic channel assignment scheme that is adapted to change of network traffic. Multi-path routing scheme was chosen to overwhelm the unreliability of wireless link. For a particular traffic state, our optimization model found a specific traffic distribution over multi-path and a channel assignment scheme that maximizes the overall network throughput. We developed a simple heuristic method for channel assignment by gradually removing clique load to obtain higher throughput. We also presented numerical examples and discussion of our models in comparison with existing research.

• IE interfaces
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• v.17 no.1
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• pp.121-127
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• 2004

In this paper, we present the base station(BS) processing capacity to provide the multimedia services in IMT-2000 wireless communication network. The IMT-2000 services are classified into two types, circuit and packet services, and user‘s environments such as indoor, pedestrian and vehicle are considered. Using the parameters of service economics and wireless technology, the user's reference traffic and BS‘s traffic are computed. The traffic is measured by throughput(kbps). Based on the measured traffic, the accommodating users in BS are also evaluated. In addition to, the BS design capacity is presented for varying the number of users and traffic distribution in different user's environments.

• Journal of Korean Institute of Industrial Engineers
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• v.27 no.1
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• pp.18-24
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• 2001

This paper presents a model and a heuristic algorithm for the Traveling Salesman Problem with Time Windows(TSPTW). The main difference of our model compared with the previous ones lies in that the time windows we are concerned are more flexible and realistic than the previous ones. In the typical TSPTW, the service at a node must begin within the time grid called the time window that is defined by the earliest and the latest time to start the service at each node. But, in real business practice, a lateness cost is usually penalized rather than the service is prohibited at all when a vehicle arrives after the latest time. Considering this situation, we develop a model with a new time window that allows an arrival after the latest time and penalizes the late arrival by charging a lateness cost. A two-phased heuristic algorithm is proposed for the model and is extensively tested to verify the accuracy and efficiency of the algorithm.

• Journal of the Korean Operations Research and Management Science Society
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• v.39 no.3
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• pp.41-49
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• 2014

Several developed countries have recently provided electric vehicle consumers and producers with financial subsidies. There has been some empirical research on the impact of government subsidies on the consumers' purchase of electric cars. However, little analytical research on the government subsidies for the electric car market exists. This research analyzes the impact of the government financial subsidies on the electric car price and technology level as well as the consumers' adoption of electric cars. This research also suggests that the government should subsidize only the electric car market to further improve the electric car technology.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.116-123
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• 2010

The Study of the Railway-saving electric water heaters to replace electric heaters when combined, Separate bathroom with hot water in winter, as coaches, without the need to warm up with hot water may be.To improve passenger service can tell. High-efficiency energy saving energy from furnace. Due to fuel cost savings and business improvements come true. Can prevent pollution.Heating the room next to railway vehicle utilization is expected to nopeulgeot.Is expected to expand gradually.

• Journal of Korean Institute of Industrial Engineers
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• v.37 no.4
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• pp.382-389
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• 2011

Salesperson Monitoring System (SMS) is geographic based information system that supports business auditing, sales area coordinating and customer management for each salesperson. Conventional SMSs focus mainly on the monitoring or logging functions, i.e., a salesperson locating or moving trail tracking. However, the schedules have been planned by human planner, and they have rarely been managed with a software system like SMS. In this paper, a mixed integer programming model for a salesperson routing schedule is provided. Then, 2-phase Genetic Algorithm (GA) is proposed to make salesperson routing schedule. Experimental results show a validity of the proposed method.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.6
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• pp.768-775
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• 2010

Automotive industry is a major business area in this country and it becomes more and more important. In order to maintain high quality of vehicles, every parts should be inspected. Among them the inspection job of the knuckle bracket holes of the outer tube of shock-absorber has been done manually until now. So, it takes long time and every product can not be inspected. An automatized inspection system was proposed utilizing machine vision technology, which was composed of a slit beam laser, CCD camera, image processing computer, special jig and illuminating back lights. An algorithm which could process images of the laser and bracket holes, then gave the position, radius, roundness of the holes, was developed. This system was applied for the good and no good products and the performance was confirmed.

• World Technopolis Review
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• v.2 no.1
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• pp.32-42
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• 2013

Science and Technology Park (STP) is perceived to be a vehicle in promoting innovation-based economic growth within the framework of regional and national innovation systems. STP is a tool to encourage regional innovation and competitiveness in increasing contribution of science and technology in economic development. STP can also be a leading sector in creating conducive environment for local community's technopreneurship. In relation to the vision outlined in the 2025 Indonesian Master Plan of Acceleration and Expansion of Indonesia's Economic (MP3EI), STP is stated to be an important element in creating innovation within the framework of Special Economic Zone among six Economic Corridors. Hence, the government of Indonesia continues to encourage the development of STPs in Indonesia by involving local governments, universities, business players and stakeholders surround the area. Ultimately, STP is a platform in developing National Innovation System (NIS) and Regional Innovation System (RIS).

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.162-168
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• 2009

FMEA(Failure Mode and Effect Analysis) is a failure analysis method for the system to identify the potential failure modes, and their effects and causes to reduce or mitigate the critical effects of the system. FMEA for railway was introduced with reliability of railway system, and this was used for identifying and analysing the possible hazards qualitatively to meet the requirements in early stage of business. In general, the overall failure data of system could be managed from design stage by FMEA, and also the countermeasures to prevent many predicted failures could be established by identification of failure modes and assement of failure effects by FMEA. Using these advantages of FMEA, the effectiveness of reliability improvement could be expected if FMEA is applied continuously in operation stage. It is essential that railway vehicles are maintained with high level of safety and reliability not to happen any failures in operation. This paper is proposed the proper FMEA for maintenance of railway vehicles compared with existing FMEA.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.169-176
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• 2009

This paper introduces 60 apply method at a railroad vehicle including basic technique of the 60. Basically rolling stock maintenance cost is high and life cycle is long. Therefore, the maintenance efficiency is the most important. Usually the length of the rolling stock life cycle is over 20years, the method of maintenance technique must be reformed periodically. So the key point of a inspection efficiency is to update the maintenance method regularly. The early days 60 method began from the thing to reduce a productions era. But after the year 2000, it took the place to the management reform technique of all business field. Finally optimal rolling stock maintenance method is introduced through the example.