• Korean Journal of Computational Design and Engineering
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• v.18 no.2
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• pp.138-147
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• 2013

The liquefaction process system is regarded as primary among all topside systems in LNG FPSO. This liquefaction process system is composed of many types of equipment. LNG equipment on offshore plants has quite different demands on the equipment compared to traditional onshore LNG plants, so the reliability analysis of this process system needs to be performed. This study investigates how DEVS formalism for discrete event simulation can be used to reliability analysis of the liquefaction cycle for LNG FPSO. The reliability analysis method based on DEVS formalism could be better model for reflecting the system configuration than the conventional reliability analysis methods, such as fault tree analysis and event tree analysis.

• IE interfaces
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• v.16 no.3
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• pp.375-381
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• 2003

To ensure competitiveness in the modern automotive market, process planning should be performed concurrently with new car developments. In automotive general assembly shops, thus, new business workflows and supporting environments are inevitable to reduce the manufacturing preparation time in developing a new car in the manner of concurrent and collaborative engineering. Since complete process planning for a whole general assembly system is a huge and complex job, several process planners should execute their planning jobs and share information. Therefore, each planner should provide others with his/her results with continuous on-line communication and cooperation. In this research, a web-based system for concurrent and collaborative process planning for automotive general assembly is developed. By using this system, savings in time and cost of assembly process planning are possible, and the reliability of the planning result is improved.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.35 no.1
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• pp.198-213
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• 2012

Navy ship acquisition management business contributed to the korean Navy and defense exports with government suppliers in Korea for over 40 years. But due to advanced technology, development trend of Navy ship and defense export requirements, it enable to make a contribution to a better system improvement are being demanded. In this paper, an adjective Navy ship acquisition process is presented in order to improve the acquisition process takes the first step for acquisition planning process to enhance the efficiency and rationality that is based on consensus of Navy ship expert and experienced. In addition, systems engineering (SE) and quality control (QC) techniques based on Modeling and Simulation are investigated to carry out efficient project management and scientific quality control system in Navy ship acquisition process. Finally, it is suggested to apply SE/QC based on M&S for Navy ship acquisition process using civilian infrastructure and organizations in order to take advantage of the world's leading domestic industry based on considering the difficult conditions of Navy ship suppliers.

• Journal of the Korean Society of Systems Engineering
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• v.15 no.2
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• pp.108-115
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• 2019

The activities of managing and controlling the configuration of a system component over its life cycle are critical tasks in developing a high safety system as well as general system development. These configuration management activities should be defined through the management plan at the beginning of the life cycle, and should be performed continuously and systematically until the end of the project after the system or product development is completed. In this study, the configuration management process applied in the development of high safety railway signaling system was introduced and an efficient application proposals of it was proposed. In particular, configuration management through the establishment of a configuration management system based on computer tools is one of the important activities of maintaining the configuration integrity of the system or product.

• Journal of Korean Society on Water Environment
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• v.33 no.4
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• pp.403-408
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• 2017

In these days, wastewater reclamation and seawater desalination play essential role in addressing the challenge of worldwide water scarcity. Particularly, reverse osmosis (RO) for seawater desalination process is commonly used due to less energy consumption than conventional thermodynamic systems. However, membrane fouling and electrical energy consumption during operation of RO system for seawater desalination haver continued to be a obstruction to its application. In this study, therefore, wastewater secondary effluent is used for osmotic dilution of seawater. Firstly, fouling behaviour of RO by simulating wastewater effluent in osmotic dilution process was measured and we calculated energy consumption of overall desalination process by theoretical equations and commercial program. Our results reveal that RO membrane fouling can be efficiently controlled by pre-treatment systems such as nano filtration (NF) or forward osmosis (FO) process. Especially FO system for osmotic dilution process is a non-pressurized membrane system and, therefore, the operating energy consumption of overall desalination system was the lowest. Moreover, fouling layer on FO membrane is comparatively weak and reversible enough to be disrupted by physical cleaning. Thus, RO system with low salinity feed water through FO process is possible as a less energy consuming desalination system with efficient membrane fouling control.

• Journal of Applied Reliability
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• v.10 no.1
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• pp.39-56
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• 2010

Statistical process control (SPC) is a powerful technique for monitoring, managing, analysing and improving the process performance. However, its has limitations such as lack of engineering, statistical skill and training, and lesser importance of activity. To solve the problems, this study proposes an intelligent SPC system using specified agents which are derived through analysis and evaluation of the SPC activities. The activities investigated by the relevant researches are categorized as collection, process analysis, diagnosis, detection, cause analysis and rule generation. Also, the evaluation criteria are established as feasibility of automation, frequency, level and time. The requirements of the agent functions are derived by the evaluation, and the types of customized agents are as data collection, store, analysis, diagnosis, monitoring, alarm and reporting. A prototype SPC system represents that the functions of the proposed agents are successfully validated.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.2
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• pp.258-267
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• 2010

The necessity of the new system development arises in both defence and commercial systems industry either when a breakthrough in technology needs to be realized in the form of a brand-new system or when the existing product already in operation needs to be upgraded to satisfy the increasing stakeholder's requirements. In the latter case, it is not rare that specific system technical specifications on the existing products are not available. The purpose of this study is to investigate how to handle the difficulty when an upgraded system is required to be developed based on the existing product whose detailed technical specifications cannot be obtained. A step-by-step process is described based on the reverse engineering of the existing product. As a result, a logical system model is obtained for the product. The process developed is further enhanced and evaluated by the computer-aided system engineering tool. The resulting logical system model should be helpful in the next phase of the new product development.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.38 no.1
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• pp.182-187
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• 2015

Process capability indices (PCIs) have been widely used in manufacturing industries to provide a quantitative measure of process potential and performance to meet the specification limits on quality characteristics. The most of existing PCIs are concerned with a single variable. But, in many cases, people want to express a integrated PCI which includes a couple of sequential processes. In this paper, we analyzed the characteristics of system PCIs such as ${\bar{Cp}}(f)$, $SC_{pk}$, $SC_{psk}$, $C^T_{psk}(m)$ and $SC_{pm}(m)$.

• Journal of the Semiconductor & Display Technology
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• v.16 no.3
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• pp.106-110
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• 2017

Due to the plasma applied from the outside, which acts as an etchant during the etching process, considerable heat is transferred to the wafer and a separate cooling process is performed to effectively remove the heat after the process. In this case, a direct cooling method using a refrigerant is suitable for cooling through effective heat exchange. The direct cooling method using the refrigerant using the latent heat exchange is superior to the cooling method using the sensible heat exchange. Therefore, in this paper, AMESim is used to design a direct refrigerant cooling system using latent heat exchange simulator was built.The constructed simulator is reliable compared with the actual experimental results. It is expected that this simulator will help to design and search for optimal process conditions.

• International Journal of Precision Engineering and Manufacturing
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• v.2 no.1
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• pp.26-32
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• 2001

An ecpert system for rotationally symmetric deep drawing products has been developed. The application for non-axisymmetric components, however, has not been reported yet. This study construsctus and expert system for non-axisymmetric motor frame which shape is classified into ellipse in deep draqing process and investigates process sequence design with elliptical shape. The developed system consists of four modules. The first is recognition of calculate surface area for non-axisymmetric products. The third is blank design module the creates an oval-shaped blank with the same surface area. The fourth is a processplanning module based on production rules that play the best important roles in an expert system for manufacturing .The production rules are generated and upgraded by interviewing field engineers. Especially, drawing coefficient, punch and die radii for elliptical shape products are considered as main design parameters. The constructed system for elliptical deep drawing product would be very useful to reduce lead time and improve accuracy for products.