• International Journal of Precision Engineering and Manufacturing
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• v.7 no.4
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• pp.34-39
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• 2006

High-precision centerless grinding machines are emerging as a means of finishing the outer diameter grinding process required for ferrules, which are widely used as fiber optic connectors. In this study, a structural characteristic analysis and evaluation were carried out using a virtual prototype of a centerless grinding machine to realize systematic design technology and performance improvements required to manufacture ferrules. The prototype consisted of a concrete-filled bed, hydrostatic grinding wheel (GW) and regulating wheel (RW) spindle systems, a hydrostatic RW feed mechanism, a RW swivel mechanism, and on-machine GW and RW dressers. The loop stiffness values of the centerless grinding machine were estimated based on the relative displacements between the GW and RW caused by grinding forces. The simulated results illustrated that a concrete-filled bed considerably improved the structural stiffness and accuracy of a high-precision centerless grinding machine.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.2
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• pp.184-190
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• 2002

This study was undertaken to judge the quality of air-tightened exhibition cases. Exhibition cases for artifacts display provide a layer of protection between the interior conditions in the exhibition case and the exterior fluctuating conditions of temperature and relative humidity in the museum environment. An infiltration model of the exhibition case was developed through the experimental measurements to calculate the number of air change rate in the exhibition case undergoing in a day, which represents the airtightness of the exhibition case. The results indicate that tighter exhibition cases provide greater protection against the fluctuating conditions of temperature and humidity outside. When the temperature and humi- dity difference between the exhibition case in-and-out is larger, some absorption materials should be applied to control the environmental conditions in the exhibition case.

• Industrial Engineering and Management Systems
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• v.8 no.1
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• pp.47-53
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• 2009

We define product line (or mix) selection problem as selecting a subset of potential product variants that can simultaneously minimize product proliferation and maintain market coverage. Selecting the most efficient product mix is a complex problem, which requires analyses of multiple criteria. This paper proposes a method based on Data Envelopment Analysis (DEA) for product line selection. Data Envelopment Analysis (DEA) is a linear programming based technique commonly used for measuring the relative performance of a group of decision making units with multiple inputs and outputs. Although DEA has been proved to be an effective evaluation tool in many fields, it has not been applied to solve the product line selection problem. In this study, we construct a five-step method that systematically adopts DEA to solve a product line selection problem. We then apply the proposed method to an existing line of staplers to provide quantitative evidence for managers to generate desirable decisions to maximize the company profits while also fulfilling market demands.

• Management & Information Systems Review
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• v.15
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• pp.71-90
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• 2004

This study has uncovered some important relationships among employees perceptions of distributive justice and procedural justice and organizational effectiveness. The present study attempts, first, to identify the perceived justice in promotion and transfer, performance evaluation, pay raise, job allocation and job fire. Second, to determine the relative importance of distributive justice and procedural justice. relationships of organizational effectiveness. The research is the identification of a modest but significant relationship between the two justice and organizational effectiveness. The result make it clear that employee find that right personnel management of fairness. To summarize the result of three variables's relationship influence is as below. The results indicated that perceptions of procedural justice as much organizational effectiveness than do perceptions of distributive justice. As also predicted, the perception of distributive justice did not impact organizational effectiveness. Therefore, Partially supporting the hypothesis. The research implications of these study suggest that great causality should be this paper' research model in three variables. The result indicate that manager must pay attention to employees perceptions of procedural justice and distributive justice.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.34 no.4
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• pp.189-196
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• 2011

In this paper, we propose a logical control-based actor-critic algorithm as an efficient approach for the approximation of the capacitated fab scheduling problem. We apply the average reward temporal-difference learning method for estimating the relative value functions of system states, while avoiding deadlock situation by Banker's algorithm. We consider the Intel mini-fab re-entrant line for the evaluation of the suggested algorithm and perform a numerical experiment by generating some sample system configurations randomly. We show that the suggested method has a prominent performance compared to other well-known heuristics.

• Journal of the Korea Institute of Military Science and Technology
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• v.8 no.2 s.21
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• pp.38-48
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• 2005

Instantaneous frequency of doppler signals is used to get the information of the relative velocity and the miss distance between a missile and a corresponding target. In this paper, we have performed time-frequency analysis and instantaneous frequency estimation with Short Time Fourier Transform(STFT), Wigner Ville Distribution(WVD) and Continuous Wavelet Transform(CWT) about the doppler signals generated by moving targets. Performance evaluation was performed using simulated doppler signals generated by a single moving target and two moving targets. From the results of the time-frequency analysis, we found that WVD method was the most efficient instantaneous frequency estimator among the three methods. But in case of two moving targets, WVD method got cross talks and CWT method got oscillation when two doppler frequencies were close to each other.

• Proceedings of the KIEE Conference
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• summer
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• pp.905-907
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• 2004

This paper deals with the PM performance evaluations in a variable flux memory motor (VFMM) using a coupled finite element method (FEM) and Preisach modeling, which is presented to analyze the magnetic characteristics of permanent magnets. The focus of this paper is the operation characteristics evaluation relative to magnetizing direction and quantity of permanent magnets on re-, demagnetization condition in a variable flux memory motor(VFMM)

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1003-1004
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• 2007

This paper deals with the PM performance evaluations in a variable flux memory motor (VFMM) using a coupled finite element method (FEM) and Preisach modeling, which is presented to analyze the magnetic characteristics of permanent magnets. The focus of this paper is the operation characteristics evaluation relative to magnetizing direction and quantity of permanent magnets on redemagnetization condition in a variable flux memory motor(VFMM).

• Journal of Magnetics
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• v.21 no.4
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• pp.629-634
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• 2016

In this study, we evaluate the performance of permanent magnets (PMs). The efficiency of attraction in the high speed region was studied using the Variable Flux Memory Motor (VFMM). It is presented in order to analyze the magnetic characteristics of PMs, using the second quadrant plan data with re- and demagnetization. In addition, this study focuses on the evaluation of operational characteristics relative to the magnetizing directions according to the d-axis currents, by using one of the finite element solutions. The feasibility of application for the VFMM has been experimentally demonstrated.

• Elastomers and Composites
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• v.54 no.2
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• pp.118-122
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• 2019

Four different polymer compounds were manufactured to make cable sheaths for the shipping industry. Two kinds of ethylene vinyl acetate (EVA) as the main matrix polymers and EVA-grafted maleic anhydride (EVA-g-MAH) as the coupling agent were selected for compounding with fire retardant, crosslinking agent, filler, plasticizer, and other additives. The properties of the four compounded materials were investigated with different contents of the fire retardant, silanecoated magnesium dihydroxide (S-MDH). In the rheology evaluation, the $t_{60}$ and ${\Delta}T$ values increased with increasing S-MDH contents. On the other hand, the tensile strength decreased with increasing S-MDH content due to a relative decrease in binder polymers. With increasing S-MDH content, fire resistance increased, but cold resistance showed no obvious enhancement due to the polar effect of vinyl acetate in EVA.