• Proceedings of the KIEE Conference
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• 1997.07c
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• pp.1038-1040
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• 1997

This paper describes dynamic characteristics test of distance relay and current differential relay using Real Time Digital Simulator on double circuit transmission line. First, The double circuit T/L modeling on RTDS was proposed and the results from the proposed model were compared with those of PSS/E. This comparison shows the possibility of dynamic test using the RTDS. The relay included about 20 test items which are apt to include maloperation of protective relays in critical situations.

• Journal of the Korean Society for Railway
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• v.7 no.4
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• pp.412-417
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• 2004

In urban rail transit systems, ground faults in the DC traction power supply system are currently detected by the potential relay, 64P. Though it detects the fault it cannot identify the faulted region and therefore the faulted region could not be isolated properly. Therefore it could cause a power loss of the trains running on the healthy regions and the safety of the passengers in the trains could be affected adversely. Two new ground fault protective relay schemes that can identify the faulted region are presented in this paper. A current limiting device, called Device X, is newly introduced in both system, which enables large amount of ground fault current flow upon the positive line to ground fault. One type of the relaying schemes is called directional and differential ground fault protective relay which uses the current differential scheme in detecting the fault and uses the permissive signal from neighboring substation to identify the faulted region correctly. The other is called ground over current protective relay. It is similar to the ordinary over current relay but it measures the ground current at the device X not at the power feeding line, and it compares the current variation value to the ground current in Device X to identify the correct faulted line. Though both type of the relays have pros and cons and can identify the faulted region correctly, the ground over current protective relaying scheme has more advantages than the other.

• Fibers and Polymers
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• v.4 no.2
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• pp.54-58
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• 2003

Previous research on healthcare workers’ protection has concentrated on liquid barrier protection by providing impermeable personal articles such as latex gloves. This property is of high importance but since most blood-borne pathogen transmissions in the healthcare industry are caused by needle-stick injuries, protection from sharp invasive instruments should also be of high concern. And since latex and alike provide no protection against needle-stick injuries, new protective systems need to be developed and evaluated. This part of the study provides a review regarding the current practice of protection and the serious problems that arise from needle-flick injuries. Additionally, the development of new protective system is described. In part II of the study, evaluation of the new system will be provided.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.6
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• pp.712-718
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• 1999

When a fault occurs in power transmission systems, protective relays play a roles of protecting the power system according to there setting values. Therefor, it is important that protective relays have high selectivity and sensitivity by correct setting the involves a large volume of data and is a complicated and very tedious, therefore vulnerable to the human errors. Also, it is very difficult to verify that the relays have correct operating parameters before the fault occurs. This paper porposed a method to testify the reliability of realys by showing the operation response to faults in the simulation of the real power system operation environment.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.5
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• pp.773-782
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• 2008

This paper describes the method for proper location of protective equipment in underground distribution cable through field test and analysis at testing lines. To prove the reliability for analysis simulated by EMTP/ATPDraw, the testing results obtained by the real test and the analysis for the same test lines were compared each other. The accuracy of analysis was proved by the comparison. Over voltages were measured and analyzed at each point of cable and switches in case of which lightning surge current was applied. The analysing method was applied to real distribution systems to select the proper location of protective equipment. It is evaluated that the location of protective equipment was properly selected.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.06a
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• pp.55-65
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• 2001

Geotextiles are usually constructed as a protective layer of geomembranes in liner systems for the solid waste landfill. A protective layer and geomembrane are susceptible to mechanical damage by coarse grains in the overlying drainage layer. In this study, therefore, the strain behavior of geotextile protective layers was investigated using three different types of devices for developing punctiform loads. The results of the study showed that the rates of strain was different depend upon device types for functiform loads. Also, It was found that the increases in strain was approximately linear in range 20 to 6$0^{\circ}C$ , and pp-filament non-woven geotextiles yielded a better efficiency than pp-staple fiber non-woven geotextiles.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.1
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• pp.50-57
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• 2003

In this paper, the protective relay setting rules of Korean electric power system are studied by analysis of errors to be considered. An accurate operation of protective relays with accurate settings are important in power system reliability. The setting rules are used from the first establishment in 1982 and revision in 1990 Therefore, it needs revise and analysis of the setting rules because of environmental changes such as voltage raise or applied new technology of power system. Two major setting rules are studied. One is the rule for Zones of distance relay for transmission lines. The other is the one of differential current in a differential relay for power transformers. The range of errors in the setting rules accepted in the field experience is studied in simulation of case study. Also some guide lines for the range of errors in the setting rules are presented from the case study using Matlab simulation.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.10
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• pp.516-523
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• 2000

In this paper, intelligent methods using digital protective relay in power supervisory control system is developed in order to protect power systems by means of timely fault detection and diagnosis during operation for induction motor which has various load environments and capacities in power systems. The spectrum pattern of input currents was used to monitor to state of induction motors, and by clustering the spectrum pattern of input currents, the newly occurrence of spectrums pattern caused by faults were detected. For diagnosis of the fault detected, the fuzzy fault tree was derived, and the fuzzy relation equation representing the relation between an induction motor fault and each fault type, was solved. The solution of the fuzzy relation equation shows the possibility of each fault's occurring. The results obtained are summarized as follows: 1) The test result on the basis of KEMC1120 and IEC60255, show that the operation time error of the digital motor protective relay is improved within ${\pm}5%$. 2) Using clustering algorithm by unsupervisory learning, an on-line fault detection method, not affected by the characteristics of loads and rates, was implemented, and the degree of dependency by experts during fault detection was reduced. 3) With the fuzzy fault tree, fault diagnosis process became systematic and expandable to the whole system, and the diagnosis for sub-systems can be made as an object-oriented module.

• The Journal of Information Systems
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• v.23 no.4
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• pp.119-145
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• 2014

Under the premise that information privacy concerns can atrophy e-commerce by causing particular behaviors of Internet users, this study focused on exploring the causes of information privacy concerns, the related information privacy protective responses of Internet users, and measures for alleviating the information privacy concerns. This study is based on the 'principal-agent theory,' and established the following as factors that cause information privacy concerns of Internet users: perceived information non-transparency; perceived action uncertainty. Also, the information privacy concerns caused by the factors were established as the cause of information privacy protective responses of Internet users. Also, the concept of 'signaling' and 'incentive,' which were presented to solve the adverse selection and moral hazard issue in the host-agent theory, was introduced to establish the following as factors that alleviate information privacy concerns: trust; informativeness. Those factors were included in the research model to conduct an empirical analysis. The analysis has revealed that both the perceived information non-transparency (p<0.01) and perceived action uncertainty (p<0.01) as to websites had a significant impact on information privacy concerns. Also, information privacy concerns of Internet users (p<0.01) had a significant impact on their information privacy protective responses who strive to protect their personal information. In addition, when trust and informativeness, which were established as factors that can alleviate information privacy concerns, were empirically analyzed, trust and informativeness had the effect of alleviating information privacy concerns. Based on the findings, the following was confirmed: Boosting the trust of Internet users in websites and offering useful information related to personal data can play a key role in alleviating the information privacy concerns of Internet users.

• International Journal of High-Rise Buildings
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• v.5 no.3
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• pp.155-165
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• 2016

A much higher level of seismic performance is needed for supertall buildings due to increased demands for their functional continuities and the recognized needs for their continuing emergence in metropolitan areas. This paper analyzes, compares, and contrasts responses recorded during the 2011 Tohoku-oki Earthquake of different supertall buildings featuring conventional and vibration-controlled engineering systems. The superior performance and advantage of the latter are pointed out, and the typical dynamic properties, response characteristics, and effects on the secondary system are discussed. Ongoing efforts to enhance vibration control performance are described, covering the development of specifications, use of performance curves and targeted displacement design, and methods to find appropriate locations of damper installation resulting in a minimized amount of dampers.