• KIEE International Transactions on Power Engineering
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• v.5A no.4
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• pp.350-356
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• 2005

Earth equipments are essential to protect humans and other types of equipment from abnormal conditions. Earth resistance and potential must be restricted within a low value. An estimation algorithm of earth parameters and equivalent resistivity is introduced to calculate reliable earth resistance in this research. The proposed algorithm is based on the relationship between apparent resistances and earth parameters. The proposed algorithm, which approximates the non-linear characteristics of earth by using the Artificial Neural Network (ANN), estimates the earth parameters and equivalent resistivity. The effectiveness of the proposed method is verified with case studies.

• East Asian mathematical journal
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• v.36 no.1
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• pp.81-90
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• 2020

Many compartment models assume a kinetically homogeneous amount of materials that have well-stirred compartments. However, based on observations from such processes, they have been heuristically fitted by exponential or gamma distributions even though biological media are inhomogeneous in real environments. Fractional differential equations using a specific kernel in Pharmacokinetic/Pharmacodynamic (PKPD) model are recently introduced to account for abnormal drug disposition. We discuss a tumor growth inhibition (TGI) model using fractional-order derivative from it. This represents a tumor growth delay by cytotoxic agents and additionally show variations in the equilibrium points by the change of fractional order. The result indicates that the equilibrium depends on the tumor size as well as a change of the fractional order. We find that the smaller the fractional order, the smaller the equilibrium value. However, a difference of them is the number of concavities and this indicates that TGI over time profile for fitting or prediction should be determined properly either fractional order or tumor sizes according to the number of concavities shown in experimental data.

• Convergence Security Journal
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• v.14 no.2
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• pp.65-72
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• 2014

This paper proposes multi-filtering method on the double firewall to prevent DDoS attack. In the first firewall, R-PA filtering algorithm and rigid hop counter filtering method are applied by analyzing packet paths. In the second firewall, packets are examined to be distinguished abnormal from normal packets. Security policy system monitors each user sessions and if the traffic is over the threshold value, the system blocks that session for an assigned time.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1623-1625
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• 2001

This paper describes a monitoring program for a substation preventive diagnostic system. The monitoring program announces the condition of the transformer and GIS like normal, warning, abnormal and danger from the absolute value of data or change trend to user. The developed system is operating in 345kV U-Ryung substation for performance and environment tests.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.169.5-169
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• 2001

This study proposes a neural network for solving optimization problems such as the TSP (Travelling Salesman Problem), scheduling, and line balancing. The Hopfield network has been used for solving such problems, but it frequently gives abnormal solutions or non-optimal ones. Moreover, the Hopfield network takes much time especially in solving large size problems. To overcome such disadvantages, this study adopts nodes whose outputs changes with a fixed value at every evolution. The proposed network is applied to solving a TSP, finding the shortest path for visiting all the cities, each of which is visted only once. Here, the travelling path is reflected to the energy function of the network. The proposed network evolves to globally minimize the energy function, and a ...

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.637-642
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• 2003

The Modified 9Cr-1Mo steel identified as T91, P91 and F91 in the ASME specification has been widely used for the construction of modern power plants. The available data on the influence of process parameters during manufacturing and fabrication on its properties are not sufficient. In this study, the influence of various thermal cycles on the hardness and the creep rupture strength was analyzed in the base metal and the weldments made in tube and pipe of a Mod.9Cr-1Mo steel. The low hardness, 155Hv, showed low creep rupture strength below the allowable stresses of T91 base metal in the ASME specification. This low value was attributed to the fully recovered dislocation structure and the weakening of precipitation hardening associated with the abnormal thermal cycles.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.10 s.181
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• pp.2420-2427
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• 2000

In contacting between surface, there is wear and the generation of wear particles. The particles contained in the lubricating oil carry detailed and important information about the condition monitoring of the machine. Therefore, This paper was undertaken for Ferrography system of wear debris generated from lubricated moving machine surface. The lubricating wear test was performed under different experimental conditions using the Falex wear test of Pin and V-Block type by Ti(C,N) coated. It was shown from the test results that wear particle concentration(WPC) ; wear severity Index(IS) and size\distribution have come out all the higher value by increases sliding friction time. By the Ferrogram a thin leaf wear debris as well as ball and plate type wear particles was observed.

• Journal of the Korean Geophysical Society
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• v.8 no.3
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• pp.137-143
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• 2005

Early detection of premonitory symptom of slope movement ensures tremendous saving of lives and repair costs from catastrophic disaster. Therefore, it is essential to constantly monitor the performance and integrity of both reinforced and un-reinforced cut slopes. We developed a novel monitoring system by using tension wire sensors. It's advantages are highly sensitivity, simple installation, large displacement measurement, durability of system, capability of remote sensing. Real-time measurement of slope surface movement is shown graphically and it gives a warning when the monitored value exceeds a given threshold level so that any sign of abnormal slope movement can be easily perceived.

• Journal of the Korean Operations Research and Management Science Society
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• v.15 no.2
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• pp.45-61
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• 1990

This study examines shareholder wealth effects in tender offers and attempts to explain abnormal return variations of bidding and target firms at announcement of takeovers using the free cash flow hypothesis of Jensen. On average, bidders with large free cash flows pay higher premia (apparently more than fair market value) to targets than do other bidders with no free cash flows. Thereby, these bidders experience negative wealth effects on announcement of tender offers. Cross-sectional regression analysis suggests that for the subsample of takeover bids where bidders have large free cash flows, the increase in the debt ratio resulting from takeover has a significant positive wealth effect for bidding firm shareholders, while it has no effect in other subsamples. The evidence is consistent with the free cash flow hypothesis.

• The Research Journal of the Costume Culture
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• v.12 no.5
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• pp.721-736
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• 2004

The aim of this study is to clarify aesthetic values and sociocultural meanings that reappears in contemporary fashion. In order to analyze aesthetic values and symbolic meanings of body decoration, I examined the concepts and expression methods of the body decoration. Also, analyzed external characteristics of expression and its internal meanings that applied in modern fashion. The expressions of body decoration represented in contemporary fashion are classified into direct and indirect methods. The direct method is expressed by tattoos, piercing, henna, make-up and body painting. And, indirect method is expressed by see-through look, body-conscious look and accessories that were utilized its patterns and the material adaptation methods. Such expression of body decoration in the modern fashion was represented into grotesque images and erotic images. The characteristics of grotesque images are abnormal state, hateful animal image and distorted or transformed body and the internal meanings are the pursuit of primitive, exoticism, the pursuit of playfulness, and resistance. The characteristics of erotic images are an exposure of body, see through, body-conscious and androgynous look and the internal meanings are the self-intoxication, naturalism and sexual pleasure.