• Journal of the Korean Society for Precision Engineering
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• v.14 no.5
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• pp.108-117
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• 1997

To prove the stability and the effectiveness of the robust non-linear friction control suggested and proved analytically in the previous paper, the describing function analysis is introduced. The instability of the Southward's nonlinear friction compensation for a digital position control and the improvement of phase margin of the robust nonlinear friction compensation are verified qualitatively through the describing function analysis. Those controls are applied to a single-axis digital servo driving experimental setup which has inherent stick-slip friction and experimental results confirm the results obtained in and the effectiveness of the robust nonlinear friction compensation for a digital position control.

• Transactions of Materials Processing
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• v.26 no.3
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• pp.162-167
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• 2017

The tensile surface residual stress in the multi-pass drawn wire deteriorates the mechanical properties of the wire. Therefore, the evaluation of the residual stress is very important. Especially, the axial residual stress on the wire surface is the highest. Therefore, the objective of this study was to propose an axial surface residual stress prediction model of the multi-pass drawn steel wire. In order to achieve this objective, an elastoplastic finite element (FE) analysis was carried out to investigate the effect of semi-die angle and reduction ratio of the axial surface residual stress. By using the results of the FE analysis, a surface residual stress prediction model was proposed. In order to verify the effectiveness of the prediction model, the predicted residual stress was compared to that of a wire drawing experiment.

• Journal of the Korea Society for Simulation
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• v.27 no.2
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• pp.49-59
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• 2018

The simulation-based weapon system effectiveness analysis is to support the decision making in the acquisition process of the defense domain. The effectiveness of the weapon system is a complexly influenced indicator from various factors such as environment, doctrine and so on. And the measurement of effectiveness can be defined differently in compliance with major issues in the weapon system. Because of this, the weapon system effectiveness analysis requires the comparative experiment of various alternatives based on the underlying assumption. This paper presents the efficient approach to reconfigure the simulation using the reflection technique. The proposed method contains the recoupling and resetting the simulation entity using DEVS(Discrete EVent System specification) formalism-based dynamic plug-in method. With the proposed method, this paper designs the effectiveness analysis environment that can efficiently handle the various alternatives of the weapon system.

• Transactions of Materials Processing
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• v.19 no.4
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• pp.242-247
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• 2010

In the multi-pass shape drawing process, it is important to design the intermediate dies for producing sound products. Up to now, the design of the intermediate dies is mainly carried out by the industrial experts based on their experience. In this study, a design program was developed to design the intermediate dies for multi-pass shape drawing process. The program was programmed by using VisualLISP. In this program the intermediate dies can be designed by using the initial material shape and the final product shape. In order to verify the effectiveness, the program was applied to design the intermediate dies of multi-pass shape drawing for producing four teeth spline and gun slide. Finally, FE analysis and shape drawing experiment were performed to verify the effectiveness of the designed intermediate dies. As a result, it was possible to produce the drawn products with the required dimensional accuracy.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.2209-2214
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• 2010

The purpose of Reliability Centered Maintenance(Hereafter, RCM) is to enhance the effectiveness and efficiency of preventive maintenance by applying the improvement plan after analysis of existing preventive maintenance. To accomplish this, it is required to collect the failure data for equipments during operation, and to carry out the quantitative criticality analysis for each equipment. This paper shows that the case study of RCM criticality analysis based on the accumulative failure data and following improvement activity for KORAIL AIRPORT RAILROAD's E&M system.

• Land and Housing Review
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• v.1 no.1
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• pp.125-134
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• 2010

Integrating corporate culture in a merger enterprise is considered as one of the most important variables to decide M&A success. This study established a conceptional model according to the preceding study on integrating corporate culture and organizational effectiveness, and formulated a hypothesis on the interrelation between a seven factors of corporate culture proposed by Pascale & Athos and Peters & Waterman and organizational effectiveness. The result of applying multi-regression analysis to test the hypothesis is as follows; firstly, all of a merger enterprise's cultural factors have meaningful influence on job involvement among organizational effectiveness; secondly, all of them have sincere influence on job satisfaction among organizational effectiveness except shared value; and thirdly, all of them except skill have significant influence on organizational harmony among organizational effectiveness. This is a significant empirical and exploratory study to ascertain the variables of corporate culture factors, and to verify their effects on organizational effectiveness.

• Journal of Software Engineering Society
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• v.24 no.3
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• pp.91-99
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• 2011

The weapon system acquisition for national defense is too costly, risky and requires high quality result. Because of these characteristics of the weapon system acquisition, the modeling and simulation is a prerequisite process for enhancing the effectiveness and efficiency of weapon system acquisition. We call the process as SBA (Simulation Based Acquisition). However the modeling and simulation entails costs of model development, execution and analysis. Thus, the SBA's effectiveness analysis is needed. Especially, we developed 4 types of index which represent the effectiveness thoroughly and we applied them to various weapon systems' acquisition process. This work presents the necessity of SBA by showing the application of suggested effectiveness index in various defense weapon system acquisition cases.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.12
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• pp.82-90
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• 2019

This analysis demonstrates the effective removal of heat generated from a solar panel's output degradation factor solar cells (the solar panel's output deterioration factor), and solves the problems of oxidation and corrosion in existing metal heat sinks. The heat-dissipating test specimen was prepared using carbon materials; then, its thermal conductivity and its effectiveness in reducing temperatures were studied using heat transfer numerical analysis. As a result, the test specimen of the 30g/㎡ basis weight containing 80% of carbon fiber impregnated with carbon ink showed the highest thermal conductivity 6.96 W/(m K). This is because the surface that directly contacted the solar panel had almost no pores, and the conduction of heat to the panels appeared to be active. In addition, a large surface area was exposed to the atmosphere, which is considered advantageous in heat dissipation. Finally, numerical analysis confirmed the temperature reduction effectiveness of 2.18℃ in a solar panel and 1.08℃ in a solar cell, depending on the application of heat dissipating materials.

• Transactions of Materials Processing
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• v.19 no.2
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• pp.132-137
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• 2010

In the multi-pass shape drawing process, the appropriate process design is very important to produce sound products. The reduction ratio, die angle, and the intermediate die shape are very important process variable of the multi-pass shape drawing. The aim of this study is the determination of the reduction ratio, die angle, and the intermediate die shape of the 2 pass shape drawing process for producing steering spline shaft. In this study, FE analysis, Taguchi method, and ANN(artificial neural network) were applied to determine the appropriate reduction ratio, die angle, and intermediate die shape. After the determination of the process variables, FE analysis and drawing experiment were performed to evaluate the effectiveness of the determined process variables. The dimensional accuracy of the final drawn spline shaft was evaluated by using 3D surface profiler and 3D laser digitizing system.

• Journal of the Korea Society for Simulation
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• v.19 no.4
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• pp.261-270
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• 2010

An integrated simulation engine provides tools, services, and standards to support various activities in the entire M&S from modeling and simulation to analysis of the simulation results. Many countries have developed integrated simulation engines to efficiently assist complex M&S activities. However, we do not have domestic simulation engines especially designed for defense M&S, therefore, developing M&S softwares still remains as a hard task with high cost and tine. OpenSIM(Open Simulation engine for Interoperable Models) is an integrated simulation engine and provides tools, services and standard interfaces for weapons analysis. OpenSIM's services are comprised of classes, member functions and data attributes which are commonly used in modeling, simulating and analyzing weapons systems. In this paper, we introduce OpenSIM's services in C++ APIs and illustrate them through an ASM example(Air to Surface Missile).