• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.378-381
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• 2000

A lot of convenient services have been recently developed under favor of rapid development of information technology and Internet The vehicle control technology which services the real-tine tracking of the location and status of the vehicles has been studied mainly by some pioneers such as research institute and company. Now the vehicle control technology is in a practical stage. The postal business is now going to change the processing architecture so that they are trying to archive two goals : (1) more efficient postal management, (2) more fast and safe delivery for mail. However there are not only many items which should be considered in order to do, but also problems which stem from the innate characteristics of postal business. In this paper, we introduce the current postal business architecture as well as the vehicle control technology. We also suggest not only the effectiveness of the vehicle technology in postal business, but also some important face what one should be taken into account about it.

• Proceedings of the Korea Society for Simulation Conference
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• 2001.10a
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• pp.269-273
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• 2001

Semiconductor wafer fabrication is a business of high capital investment and fast changing nature. To be competitive, the production in a fab needs to be effectively planned and scheduled starting from the ramping up phase, so that the business goals such as on-time delivery, high output volume and effective use of capital intensive equipment can be achieved. In this paper, we propose Stand Alone layout and In-Line layout are analyzed and compared while varying number of device variable changes. The comparison is performed through simulation using ProSys; a window 98 based discrete system simulation software, as a tool for comparing performance of two proposed layouts. The comparison demonstrates that when the number of device variable change is small, In-Line layout is more efficient in terms of production quantity. However, as the number of device variable change is more than 14 titles, Stand Alone layout prevails over In-Line layout.

• Proceedings of the KIEE Conference
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• 1992.07a
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• pp.51-54
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• 1992

Protection and control systems play a prominent part in avoiding power delivery interruptions and help to get a fast and secure restoration when a failure occurs. In order to meet the higher functional requirements on modern power system, protection speed, selectivity, sensitivity, dependability, and security are essential to ensure reliability. These functions on be satisfied by taking advantage of microprocessor and communication technologies, and digital protection relays (systems) have been developed and applied to real power system enhancing reliability and saving money. It is necessary to have a tool to analyze the functions and algorithms of digital relays for installing them to power system. The purpose of this study is to develop a digital relay simulation program to estimate digital relay performances during system faults. Components of digital protective relay including analog filter, sampling unit, digital filter, and relay logic are modeled in this program.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1996.06b
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• pp.115-121
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• 1996

Interactive CATV system is under development to provide multimedia applications such as movies on demand, home shopping, etc. In addition to the conventional analog cable TV services. This system applies international standard DAVIC, ATM forum, DSM-CC etc. The system adopts modular architecture design approach so that the system can be adaptive to the fast moving technology wavefront. In this article, interactive CATV system and essential elements such as video server, delivery network and Set-Top-Box(STB) and related international standardization are introduced.

• Journal of the Korea Society for Simulation
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• v.11 no.3
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• pp.59-65
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• 2002

Semiconductor wafer fabrication is a business of high capital investment and fast changing nature. To be competitive, the production in a fab needs to be effectively planned and scheduled starting from the ramping up phase, so that the business goals such as on-time delivery, high output volume and effective use of capital intensive equipment can be achieved. Project executed that use conveyor in bay semiconductor A line. But conveyor capability is lacking and rundown happened in equipment. Do design without normal simulation and conveyor system failed. The comparison is peformed through simulation using .AutoMod a window 98 based discrete system simulation software, as a tool for comparing performance of proposed layouts. In this research estimate optimum conveyor capability, there is the purpose.

• Proceedings of the Safety Management and Science Conference
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• 2005.05a
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• pp.225-230
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• 2005

A study is for the approach that we could reduce the logistics costs through uprising the efficiency, complying to the demand in time, stock management based on the general production plan in the point of SCM. We will take following steps to get the goal. First, we will overview the physical distribution expenses annually. Second, will find the main cause of optimal load loss by improper container and lack of delivery flexibility to the demand. Third, the goal will be inferred through the fast information share based on organic relationship, the establishment of general production plan, the improvement of stock management plan. By way of this process, it can be accomplished expense reduction as well as flexible establishment of the reduction of worker's load.

• Archives of Pharmacal Research
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• v.18 no.1
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• pp.18-21
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• 1995

Poly(ethylene glycol)(PEG) macrocers teminated with acrylate groups and semi-interpenetrating polymer networks (IPNs) composed of poly-.epsilon.-capolactone(PCL) and PEG macromer were syntheswized with the aim of obtaining a bioerodible hydrogel that could be used to release drugs for implantable delivery system. Polymerization of PEG macromer resulted in the formation of cross-linked gels due to the multifunctionality of macromer. Non-crosslinked PCL chains were interpenetrated into the cross-linked three-dimensions networks of PEG. The IPNs, largw drug loading lower concentration of PEG macromer in the IPNs concentration and the higher molecular weight of PEG macromer. Also, 5-FU was more fast released than hydrocortisone to the increased water solubility.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.152-157
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• 2001

This paper presents the design method of the new controller for looper system in hot strip finishing mill. Looper response time is related to the performance of the tension control to reduce the delivery width error. The quality of the hot strip product, especially width deviation at the top of the strip, is influenced greatly by the precision of tension control. In this paper, a new fuzzy PID control system is designed to obtain the fast looper angle response and the high control precision. The computer simulation to verify the performance of the new controller is executed. From the results of the simulation, the tension control can obtain better performance than that of the conventional PID case.

• Journal of the Korea Safety Management & Science
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• v.7 no.2
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• pp.41-56
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• 2005

A study is for the approach that we could reduce the logistics costs through uprising the efficiency, complying to the demand in time, stock management based on the general production plan in the point of SCM. We will take following steps to get the goal. First, we will overview the physical distribution expenses annually. Second, will find the main cause of optimal load loss by improper container and lack of delivery flexibility to the demand. Third, the goal will be inferred through the fast information share based on organic relationship, the establishment of general production plan, the improvement of stock management plan. By way of this process, it can be accomplished expense reduction as well as flexible establishment of the reduction of worker's load.

• Journal of Communications and Networks
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• v.11 no.3
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• pp.306-317
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• 2009

We consider the problem of architecting a reliable content delivery system across an overlay network using TCP connections as the transport primitive. We first argue that natural designs based on store-and-forward principles that tightly couple TCP connections at intermediate end-systems impose fundamental performance limitations, such as dragging down all transfer rates in the system to the rate of the slowest receiver. In contrast, the ROMA architecture we propose incorporates the use of loosely coupled TCP connections together with fast forward error correction techniques to deliver a scalable solution that better accommodates a set of heterogeneous receivers. The methods we develop establish chains of TCP connections, whose expected performance we analyze through equation-based methods. We validate our analytical findings and evaluate the performance of our ROMA architecture using a prototype implementation via extensive Internet experimentation across the PlanetLab distributed testbed.