• Journal of KSNVE
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• v.10 no.5
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• pp.830-837
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• 2000

This paper deals with an analysis and countermeasure of escalator vibration. The vibration characteristics of escalators are studied theoretically and experimentally to fine the main cause of severe vibration. The main source of vibration in escalators is found to be chordal effect due to the step chain and sprocket system. It is also found that the vibration become significantly large at so called no load condition, in which the load due to passengers, during down-moving, is equal to the resistive force in the driving system. Dynamic absorbers are implemented to suppress the vibration, A theoretical analysis is made to determine the appropriate dynamic absorber. Theoretical and experimental study shows that dynamic absorber is effective to suppress the vibration in escalators.

• Fire Science and Engineering
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• v.30 no.5
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• pp.137-143
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• 2016

The use of chemicals is increasing due to industrial advancement and diversification. In addition, the number of chemical accidents are increasing at the same time. A multifaceted effort in chemical accidents is needed for efficient prevention and countermeasures. This paper presents, under the current Act, a chemical accident case, including the material safety data sheet (MSDS) through the chemical accident prevention and measures for improvement with regard to research.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.10a
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• pp.644-647
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• 2004

Developing into information oriented society, dependency on network systems increases gradually in the area of economy, society and so on. Under that circumstance, temporary stop or damage of integrity of network system may have a strong impact on economic activities and overall society. Recently, threat of cyber terrorism, organized hostile action to government or industry through network, is increasing. Because of the features of network, it is not sufficient only a nation's countermeasure against Cyber terrorism, so international cooperation is needed. We review the status of countermeasure against cyber terrorism and examine several considerations for policy establishment.

• Journal of the Korean Home Economics Association
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• v.23 no.2
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• pp.13-19
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• 1985

While the appearance of new textiles and processing materials results in the improvement in quality of clothes and its luxury, a question about the irritation of clothes on the human body must be raised. In Japan and many countries in Europe, they are searching for a countermeasure against the bad influence of clothes on the human body for the purpose of protecting consumers. In our country, a little bit of study about the skin irritatio has been carried out. In this thesis, the literature on the kinds of the irritation of clothes on the human body was studied and analysed. And then I arranged it from the view-point of clothing hygienics. For example, we should observe the legal regulations and the administrative control in the process of production and distributive management of clothes for our safety. Therefore the authorities concerned must have preparations for the safety and this monograph is going to give information for it.

• Proceedings of the KIEE Conference
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• 1998.07c
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• pp.1159-1162
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• 1998

The induced voltage of underground pipelines caused by the stray current not only do harm to workers and instruments. but also cause big accident such as gas explosion. The AC stray current is mainly produced by the grounding system of the 22.9kV distribution power system and the DC stray current is mainly produced by the subway system. The mechanism of AC and DC induction, stray current failure examples of domestic and foreign countries and the countermeasure of the AC and DC induction are described.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.59-61
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• 2003

This paper demonstrates an analysis of harmonics at the high speed railway substation and proved on this countermeasure using the PSCAD/EMTDC simulation tool. First, high speed railway feeding system is composed using PSCAD/EMTDC electrical railway feeding system model in advance. Second, This paper applications line capacitance values as feeder-trolley, trolley-rail and feeder-rail to analysis harmonics more accuracy in advance did not application. This capacitance values calculate using the EMTP(Electro Magnetic Transient Program). Third, the tractions are arranged in the section that substation supplies power, and this paper take the simulation each case(fractions composition amount) to see harmonic propagation from traction to substation. As a result, generated harmonics at traction can confirmed that harmonics did not reduce at utility source. This harmonics have an influence on bulk power system. Finally, this paper introduces the methods of harmonics effect minimum. This paper proved harmonics reduce effect through the passive filters application.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.2
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• pp.247-252
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• 2016

The latest offshore wind turbines are easily exposed to lightning strikes because they are designed with longer blades and taller height to satisfy the growing capacity demands. The generation facilities and elements of the offshore wind farm are more vulnerable to lightning damage because of more severe, unpredictable weather conditions. Therefore, this paper presents the analysis of measure for lightning overvoltage mitigation in offshore wind farm planned in South Korea southwest seashore. The sensitivity analysis includes the steady state and transient state characteristics of offshore wind farm and proposes the countermeasure for mitigation of transient overvoltage by considering earth resistivity of the offshore environment.

• ETRI Journal
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• v.43 no.4
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• pp.746-757
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• 2021

Side-channel attacks pose an inevitable challenge to the implementation of cryptographic algorithms, and it is important to mitigate them. This work identifies a novel data encoding technique based on 1-of-4 codes to resist differential power analysis attacks, which is the most investigated category of side-channel attacks. The four code words of the 1-of-4 codes, namely (0001, 0010, 1000, and 0100), are split into two sets: set-0 and set-1. Using a select signal, the data processed in hardware is switched between the two encoding sets alternately such that the Hamming weight and Hamming distance are equalized. As a case study, the proposed technique is validated for the NIST standard AES-128 cipher. The proposed technique resists differential power analysis performed using statistical methods, namely correlation, mutual information, difference of means, and Welch's t-test based on the Hamming weight and distance models. The experimental results show that the proposed countermeasure has an area overhead of 2.3× with no performance degradation comparatively.

• Journal of the Korean Geosynthetics Society
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• v.9 no.4
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• pp.57-66
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• 2010

This study is described in heavy metal pollution by the stony mountain development using field case. The heavy metal pollution is investigated for nearby area (soil and stream) of the developed stony mountain, and then the countermeasure using contamination analysis is suggested. The investigation result indicated that contamination of Sammak stream caused by the stone dust and leachate at the stony mountain development. Therefore, the heavy metal pollution is evaluated by using Pollution Index(PI). The evaluation results confirmed that the contaminated groundwater was the leading cause of the contamination in Sammak stream and nearby soil. Therefore, the Permeable Reaction Barrier(PRB), which has a environmentally-friendly reactant, should be applied to control a heavy metal of groundwater, and it will be a reasonable countermeasure.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.1
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• pp.67-74
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• 2009

Information Effluence leaks are caused by the wide use of the P2P program in Japan and Korea lead by the increase of internet use and network infrastructure expansion. This research confirms the seriousness of the data collected from the P2P leaks of the two countries and furthers its study by researching how countermeasures are applied. The effectiveness is verified by collecting data according to countermeasure applied periods. Both countries had information leaks, but in the case of Japan, not only personal information leaks but corporation, administrative agency, military, and others in a wide range as well. As a countermeasure against information effluence, Korea is enforcing counter plans mainly against the P2P service businesses and for Japan, various plans are taken such as business guides for each agency, organization management, SW development and supply, HW supply, and ect. The leaks in Japan were more severe than the ones in Korea but they had well planned countermeasures that were applied. Therefore if the Japanese countermeasure on information effluence of P2P programs is taken as a lesson, Korea can prevent the problem of leaks beforehand.