• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.127_128
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• 2009

A new technique using a search method which is based on fuzzy multi-criteria function is proposed for GMS(generator maintenance scheduling) in order to consider multi-objective function. Not only minimization of probabilistic production cost but also maximization of system reliability level are considered for fuzzy multi-criteria function. To obtain an optimal solution for generator maintenance scheduling under fuzzy environment, fuzzy multi-criteria relaxation method(fuzzy search method) is used. The practicality and effectiveness of the proposed approach are demonstrated by simulation studies for a real size power system model in Korea in 2010.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.7
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• pp.360-365
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• 2017

Recently, development efforts of triple-effect absorption chiller have been increased in order to improve the efficiency of double-effect absorption chiller. However, triple-effect absorption chiller has some disadvantages, including high corrosion characteristic of LiBr solution at high temperature of $200^{\circ}C$. Moreover, it is necessary to develop new components for operation under high pressure of 2 bars even though COP is increased to 1.6 or 1.7. The objective of this study was to introduce a new system by combining double effect absorption chiller with single effect absorption chiller with multi-generators using bypass flow of LiBr dilute solution to $3^{rd}$ generator to overcome the disadvantages of triple-effect chiller and improve energy efficiency. Results indicate that the new absorption cycle had a much higher efficiency than double-effect chiller system, showing significant improvement when bypass solution flow rate of 25% was applied to the $3^{rd}$ generator using the main dilute solution of the absorber. The COP of the new chiller system was found to be 1.438, which was 21.7% higher than that (1.18) of the present double-effect system. The COP was decreased when solution by-pass rate to the $3^{rd}$ generator was increased. In addition, lower cooling water temperature caused higher COP. Therefore, the multi-generator system with by-pass solution might be an excellent chiller alternative to triple-effect absorption chiller with higher efficiency.

• Journal of the Korea Society of Computer and Information
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• v.3 no.2
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• pp.99-104
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• 1998

In this paper I designed test pattern generator which will be completely detected the faults of multi-stage Logic Circuit. 1 generated this pattern using the test pattern generation Logic Circuit. The generated test patterns compared with the exhausted testing was decreased pattern. This test pattern generator will detect the all single stuck-at faults in the multi-stage Logic Circuit. The choice of which of the many I.C testing methods to use can have a effect on the success or failure of the fault detected. One of the most important considerations is cost and designed test pattern generator is very low cost type.

• Proceedings of the KIEE Conference
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• 2001.05a
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• pp.92-94
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• 2001

This paper investigated the real-time generator swing prediction by some researchers. And the first swing stability assessment based on EAC(Equal-Area Criterion) by using phasor measurement unit is proposed. Also we proposed the multi-swing prediction techniques, which is to estimate system parameters by using least square method / extrapolation with phasor measurement units. And the multi-swing prediction is performed with the estimated parameters. Future works are necessary to verify the proposed approaches in this paper.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.04a
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• pp.631-634
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• 1996

This paper describes an intelligent user interface to define simulation models from the process and resource models. It also explains an automatic program generator of discrete event simulation model for shop floor control in a flexible manufacturing system. Especially, the paper is focused on the design and development of methodology to automate simulation modeling from the system description. Describing a shop floor control system in simulation is not an easy task since it must resolve various decision problems such as deadlock resolution, part dispatching, resource conflict resolution, etc. The program generator should be capable of constructing a complete discrete simulation models for a multi-product and multi-stage flow shop containing the above mentioned problems.

• Proceedings of the Korea Society for Simulation Conference
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• 1996.05a
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• pp.15-15
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• 1996

A shop floor control system (SFCS) is the central part of a CIM system used to control the activities of several pieces of manufacturing equipment (e.g., NC machines, robots, conveyors, AGVs, AS/RS). The SFCS receives orders and related process plans, and then performs selecting a specific process routing, allocating resources, scheduling the workpieces, downloading the processing instructions (e.g., RS-274 instructions for NC machines, VAL II programs for robot), monitoring the progress of activities, detecting and recovering from errors, and preparing reports on the status of the manufacturing system. Simulation has been utilized in discovering control policies used for resolving shop floor be control problems such as resource contentions, part dispatching, deadlock. The simulation model must be designed to respond to real-time data coming from a shop floor. However, to rapidly build a realtime simulation model of SFCS cannot be easily accomplished. This talk is to address an automatic program generator of discrete event simulation model for shop floor control from process plans and resource models. The program generator is capable of constructing complete discrete simulation models for multi-product and multi-stage flexible manufacturing systems.

• Journal of Integrative Natural Science
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• v.2 no.4
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• pp.252-264
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• 2009

Lithographic data obtained from PHS(polyhydroxy styrene) having various functionalities were investigated by using a photoacid generator based on diazo and onium type. Chemically amplified photoresist based on the KrF type photoresist was developed by using a photoacid generator and multi-functional resin. Thermal stability for the photoacid generator showed that the increase of loading amount of photoacid generator resulted in the decrease of glass transintion temperature (Tg). The photoacid generators having methyl, ethyl, or propyl group in their cationic structure produced T-top structure in pattern profile due to the effect of acid diffusion during the generation of acid in the resist. The increase of carbon chain length in the anionic structure of photoacid generators resulted in lower pattern resolution due to the interruption of acid diffusion.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.11a
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• pp.39-40
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• 2007

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.589-590
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• 2010

• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.3
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• pp.69-76
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• 2012

An achieving method of highly progressive pressure gradient is presented to enhance the missile ejection system's performance by using a gas generator in the condition of preventing erosive burning. To obtain and confirm a stable burning, a ground burning test was performed to evaluate the new methods of a radial-hole and a multi-row propellant grain. The test results show that a radial-hole grain takes good effect on erosive burning and not on ejection performance. On the other hand, a multi-row grain which reduces the length-to-diameter ratio(L/D) of grain is very effective to prevent the erosive burning and to enhance the ejection performance simultaneously.