• Journal of the Korean Society for Railway
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• v.15 no.2
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• pp.97-103
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• 2012

Composite honeycomb sandwich plate is light and strong. It is easy to produce. It began to be applied to the bodyshell of rolling stock. Generally, weight saving amounts to 27%. However, the material cost of it is much higher than that of aluminum extrusion profile, which prevents popular use of it for bodyshell. In this paper, manufacturing processes of two light materials were compared to investigate cost impact. After cost breakdown was defined, economics of two materials was analyzed using the previous cost data. Easy production of composite bodyshell could compensate for higher material cost. Mass production of composite bodyshell can make the equipment cost lower for the composite bodyshell so that it may have strong competitiveness to the aluminum bodyshell. Operational energy saving due to weight reduction was also presented referring to the actual statistical data in a metro line.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.6
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• pp.199-205
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• 2014

We would like to study and develop the optimized WBS(Work Breakdown Structure) considering project's range, schedule, cost and human resources management with defining phased work in main task and preceding and escorting relationships for effective small and medium enterprises' informatization through standardized PSDM(Production System Development Methodology). For more systemic and effective system built-up, it introduces production information with WBS study which is appropriate for the small and medium enterprises with setting up management items for enhancing system's reliability, quality, productivity, smooth communication among the participated enterprises such as the small and medium enterprises, IT enterprises, and supervision enterprises, and operational support including maintenance of the built system. This study is purpose of helping a lot of the small and medium enterprises and IT enterprises to build up the systems more effective and reliable within planned schedule using the standardized methodology.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.5
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• pp.863-869
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• 2017

In this study, the information breakdown structure of water purification plant has been made by classifying various the water purification methods and facilities. this can be utilized as a code system of computer for integrating information and analyzing quantitative of environmental impact and calculating cost of maintenance and energy consumption which was used during life cycle of water purification plant. Since the construction information contains many heterogeneous information, it is very important to have a code system for managing the integrated information. In addition, since water purification plant facilities are mainly composed of installation of facilities including many processes, a more detailed classification code is required. Therefore, in this study, the water purification breakdown structure which is not yet attempted in Korea was constructed by using facet classification system.

• Journal of the Korean Society for Railway
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• v.18 no.4
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• pp.344-353
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• 2015

Recently, the utilization of the BIM system has been extended to cost and resource simulation, visualized management of construction site information and application of augmented reality including basic 3D modeling. Therefore, various BIM functions are being developed for practical applications. However, since clear classification criteria and knowledge information of BIM functions are not sufficient for field engineers, it is difficult to identify the necessary BIM functions for a construction project. This study suggests a BIM function breakdown structure considering the individual functional properties and a process model that can be ordered by applying BIM in a railway construction project. The proposed delivery model is used to obtain a practical utilization of BIM by analyzing features applicable to railway construction projects; model is verified using a case project.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05a
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• pp.65-68
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• 2003

Interconnected power system operation has given rise to the problem of increased fault levels and leads to over stressing of all the components. Use have been made of recently developed high Tc superconductor in devising a superconducting fault current limiter (SFCL) that promises optimum performance in terms of capital cost, size, auto sensing, operational losses, response time and reliability. Recently, research about the application of the SFCL is actively progressing in Korea. To be applied for SFCL practically, the electrical insulation design of SFCL must be developed. Therefore, this paper presents the result of an investigation of the dielectric characteristics of turn-to-turn insulation for SFCL in liquid nitrogen. The dielectric characteristics of turn-to-turn insulation models of SFCL were investigated. We obtained following results. The breakdown voltages increased as the spacer thickness and length increased. And the breakdown voltages of turn-to-turn model without spacer were higher than the breakdown voltages of turn-to-turn model with spacer under impulse as well as AC voltages. The information gathered in this test series should be helpful in the design of liquid nitrogen filled SFCL.

• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.5
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• pp.673-681
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• 2014

In this paper, a novel low specific on-resistance SOI LDMOS Device with P+P-top layer in the drift region is proposed and investigated using a two dimensional device simulator, MEDICI. The structure is characterized by a heavily-doped $P^+$ region which is connected to the P-top layer in the drift region. The $P^+$ region can modulates the surface electric field profile, increases the drift doping concentration and reduces the sensitivity of the breakdown voltage on the geometry parameters. Compared to the conventional D-RESURF device, a 25.8% decrease in specific on-resistance and a 48.2% increase in figure of merit can be obtained in the novel device. Furthermore, the novel $P^+P$-top device also present cost efficiency due to the fact that the $P^+$ region can be fabricated together with the P-type body contact region without any additional mask.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.43-44
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• 2009

3D bridge information models for a concrete box-girder bridge were built and a typical application example for the estimation linked with the 3D models was proposed. 3D geometry objects with PBS (product breakdown structure) were constructed using standard classification codes and 2D drawings. Information on the amount of materials according to the classification codes was utilized for the estimation system. A process for the estimation of concrete and rebars was developed and verified through the pilot test. Optimization of rebar fabrication was suggested as an additional function and was utilized for the cost reduction and standard fabrication.

• Journal of Korean Society for Quality Management
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• v.20 no.2
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• pp.33-43
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• 1992

Items are assumed to fail by degradation. An appropriate stochastic model of such item is a cumulative process in which an item can fail only when the total amount of wear exceeds a prespecified failure level. This paper presents replacement policy in which an item is replaced at a certain level of wear before failure or at failure, whichever occurs first. Yet, when measuring the item wear level is very expensive, destructive or time-consuming, it may be economical to use substitutive characteristics that are correlated with the item wear level and relatively inexpensive to measure. The item's wear level could usually be estimated by monitoring such substitutive characteristics only except for a breakdown, which may be observed immediately at its occurrence. The purpose of this paper is to find an optimal periodic replacement policy based on such substitutive characteristics that balance the cost of replacement with the cost of failure and result in a minimum total long-run average cost per unit time. The optimal level of substitutive characteristics to replace the item is obtained. Numerical example illustrate how the model can be used to determine the optimal replacement policy.

• Journal of Electrical Engineering and Technology
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• v.13 no.3
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• pp.1346-1354
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• 2018

Quality of the power system depends upon the reliability of its components such as transformer, transmission lines, insulators, circuit breakers and isolators. The transient voltage due to internal or external reasons may affect the insulation level of the components. The insulation level of these components must be tested against these conditions. Different studies, testing of different electrical components against high voltage impulses and different industrial applications rely on the international manufactures for pulsed power generation and testing, that is quite expensive and large in size. In this paper a model of impulse voltage generator with capacitive load of pin type insulator is studied by simulation method and by an experimental setup. A ten stage high voltage impulse generator (HVIG) is designed and implemented for different applications. In this proposed model, the cost has been reduced by using small and cheap capacitors as an alternative for large and expensive ones while achieving the same effectiveness. Effect of the distributed capacitance in each stage is analyzed to prove the effectiveness of the model. Different values of front and tail resistances have been used to get IEC standard waveforms. Results reveal the effectiveness at reduced cost of the proposed model.

• Journal of the Korea Institute of Military Science and Technology
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• v.25 no.5
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• pp.530-538
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• 2022

Recently, the R&D of weapon systems has been strengthened in terms of economic cost management throughout the entire life cycle from performance. This study proposes the method for setting the optimal maintenance concept based on RAM-C in weapon system acquisition stage by calculating the operation & maintenance cost as well as reliability, availability, and maintainability. First, we design a simulation model for analysis of weapon system logistic supportability. In addition, information such as weapon system Part Breakdown Structure, operation & maintenance system, cost, and etc for simulation analysis, is applied. Based on the obtained simulation results, the optimal plan is selected among alternatives designed with various maintenance concepts through normalization and weight setting. It is expected to be of technical help in the application of RAM-C in the weapon system acquisition stage.