• Journal of the Korean Society of Manufacturing Process Engineers
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• v.2 no.3
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• pp.76-83
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• 2003

Recently, the field of the engineering has been studied about optimum design continuously. Verified data by comparison with simulation and dynamic characteristic analysis enables the design of a machine tool to be modified easily and effectively concerning to the mode shape of the vibration. Especially, BC-500 Line Center has got some problems causing vibration which mainly come from Column and ATC part. So it is necessary to solve those problems by the two kinds of method such as changing structural design and reinforcing with ribs. In this paper, column and ATC part of BC-500 Line center are modified by an optimum design by the analysing method of FEM to avoid vibration. As a result, a more stable machine tool was designed by this simulation as optimum condition.

• Journal of the Korea Society of Computer and Information
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• v.22 no.3
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• pp.69-79
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• 2017

In this paper, we propose our four-phase life cycle of P2P botnet with corresponding detection methods and the future direction for more effective P2P botnet detection. Our proposals are based on the intensive analysis that compares existing P2P botnet detection schemes in different points of view such as life cycle of P2P botnet, machine learning methods for data mining based detection, composition of data sets, and performance matrix. Our proposed life cycle model composed of linear sequence stages suggests to utilize features in the vulnerable phase rather than the entire life cycle. In addition, we suggest the hybrid detection scheme with data mining based method and our proposed life cycle, and present the improved composition of experimental data sets through analysing the limitations of previous works.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1127-1132
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• 2000

Impulsive acoustic and vibration signals within rotating machinery are often induced by irregular impacting. The detection of these impulses can be useful for fault diagnosis purposes. Recently there has been an increasing trend towards the use of higher order statistics for fault detection within mechanical systems based on the observation that impulsive signals tend to increase the kurtosis values. This paper considers the use of the third and fourth order Wigner moment spectra, called the Wigner bi- and tri- spectra receptively, for analysing such signals. Expressions for the auto-and cross-terms in these distributions are presented and discussed. It is shown that the Wigner trispectrum is a more suitable analysis tool and it performance is compared to its second order counterpart for detecting impulsive signals. These methods are also applied to measured data sets from an industrial gearbox.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.4
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• pp.117-123
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• 2002

Measurement of ground resistance is the basic and important procedure to evaluate the proriety of grounding systems performance. In the field, however, it is not an easy task to measure ground resistance accurately, because locating a right position of zero potential for accurate GPR(Ground Potential Rise) measurement is very difficult, especially in case of a grounding electrode with large dimension. In this paper, the estimation method of ground resistance by analysing earth surface potential distribution around the grounding electrodes has been described.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.822-827
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• 2009

Recently, a large amount of budget was invested in improving the railway tracks(double tracking, route improvement) of Janghang and Jungang line. However, further action to enhance the investment effect has been needed because the desired effect have not been obtained. This study was designed to evaluate the effect of track improvement briefly by examining the project summary of Janghang and Jungang line railway line improvement and analysing the change of the transport performance and revenue. The results of this study can be applied not only to establish an operation plan for maximizing the revenue of rail operation also to enhance an effect of track improvement.

• Management & Information Systems Review
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• v.26
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• pp.133-152
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• 2008

In the knowledge and network economy, standards and standardization become an important factor in determining the competitiveness of nations and firms. This paper analyses some cases of firms' strategic standardization. We defined the concept of standards, standardization, strategic standardization, and standardization management, which have been unfamiliar in the academic society. The standardization strategy can be categorized into four types according to firm's management objectives or benefits, including technological innovation, market creation/extension. cost-down, and accreditation. This classification of standardization strategy is very useful in analysing the various kinds of the cases of strategic standardization implementation. We found that standards and standardization have a positive influence on firm's overall performance. In some cases, for example, Dell Computer, Sun Microsystems, Deere & Company, etc., strategic standardization plays a role as a key success factor(KSF).

• International Journal of Air-Conditioning and Refrigeration
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• v.14 no.4
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• pp.131-137
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• 2006

The absorber in which heat and mass transfer phenomena occur simultaneously is one of the most critical components in the absorption system. It has the most significant influence on the performance and the size of the absorption system. During the absorption process, heat and mass transfer resistances exist in both liquid and vapor regions, so that the heat transfer mode should be carefully selected to reduce them. The objective of this paper is to review the previous papers analysing mathematical models of simultaneous heat and mass transfer phenomena during the absorption process. The most conventional working fluids ($H_2O$LiBr and $NH_3/H_2O$) are considered and the most common absorption modes (falling film and bubble mode) are dealt with in this review.

• Journal of the Korea Safety Management & Science
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• v.12 no.4
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• pp.23-29
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• 2010

There are two kind of method to perform a safety management in industrial field. One is a management by safety manager employed in company and another one is safety management by acting agency. In case of the company that managed by the acting agency dose not coincide with the state of company and safety management performance because of the safety management is carry out by periodically. Therefore it is considered that the sufficient safety management is difficult. And a company that employ a safety manager also show a low level of safety management compare with the advanced country in view of safety and health. From the statistics of accident rate of the company, it is necessary that an improved safety management through the studying and analysing a coverall matters for the company that managed by acting company.

• Journal of Korea Multimedia Society
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• v.22 no.9
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• pp.1020-1028
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• 2019

Cerebrovascular disease is a common disease in the elderly population. However, we do not have enough understanding of brain-related diseases. Recent advances in microscopy technology have resulted in the acquisition of vast amounts of image data sets for small organs, and it has become possible to handle vast amounts of image data sets due to improved computer performance and software technology. In this paper, the author proposes introduce a method for classifying and analysing only cerebrovascular information in the mouse brain image, as well as a quantitative measure of the portion of the cerebrovascular in the mouse brain. The study of the cerebrovascular structure is significant, and it can be helpful to improve the understanding of cerebrovasculature. As a result, the author expects that this study will be useful for neuroscientists conducting clinical research.

• Structural Engineering and Mechanics
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• v.78 no.1
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• pp.67-75
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• 2021

This work studies the behaviour of a steel portal frame selection under fire exposure, considering both span lengths and fire exposure times as variables. Such structures combine carbon steel (S275), fireproof micro-alloyed steel (FR), and coatings of intumescent paint with variable thicknesses, improving thereby the flame retardant behaviour of the steel structure. Thus, the main contribution of this study is the optimization of the portal frames by combining both steels, analysing the resulting costs influence on the final dimensions. Besides, the topological optimization of each steel component within the structure is also defined, in accordance with the following variables: weather conditions, span, paint thickness, and cost of steel. The results mainly confirmed that using both FR and S275 grades with intumescent painting is the Pareto optimum when considering performance, feasibility and costs of such portal frames widely used for industrial facilities.