• Smart Structures and Systems
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• 제3권3호
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• pp.385-403
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• 2007

The effectiveness of the newly developed smart passive control system employing a magnetorheological (MR) damper and an electromagnetic induction (EMI) part for seismic protection of base isolated structures is numerically investigated. An EMI part in the system consists of a permanent magnet and a coil, which changes the kinetic energy of the deformation of an MR damper into the electric energy (i.e. the induced current) according to the Faraday's law of electromagnetic induction. In the smart passive control system, the damping characteristics of an MR damper are varied with the current input generated from an EMI part. Hence, it does not need any control system consisting of sensors, a controller and an external power source. This makes the system much simpler as well as more economic. To verify the efficacy of the smart passive control system, a series of numerical simulations are carried out by considering the benchmark base isolated structure control problems. The numerical simulation results show that the smart passive control system has the comparable control performance to the conventional MR damper-based semiactive control system. Therefore, the smart passive control system could be considered as one of the promising control devices for seismic protection of seismically excited base isolated structures.

• 한국안전학회지
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• 제31권3호
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• pp.47-52
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• 2016

This paper describes the design and fabrication of high frequency ground impedance measuring system for assessment of grounding system for Lightning protection. The ground impedance measuring system has been designed and fabricated which makes it possible to assess the ground impedance by frequency ranges from 100 Hz to 1 MHz. The effective grounding systems having a very low impedance to electromagnetic disturbance such as lightning surges and noises in microelectronics and high-technology branches are strongly required. In order to analyze the dynamic characteristic of grounding system impedances in lightning and surge protection grounding systems, it is highly desirable to assess the ground impedances as a measure of performance of grounding system in which lightning and switching surge currents with fast rise time and high frequency flow. The measuring system is based on the variable frequency power supply and consists of signal circuit part, main control part, data acquisition and processing unit, and voltage and current probe system. The ground impedance measuring system can be used to assess grounding system during occurrence of lightning.

• 디지털콘텐츠학회 논문지
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• 제18권4호
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• pp.795-802
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• 2017

자연재난 및 사회재난 등으로 인해 국가기반시설의 기능이 정지되어 국가기반체계가 마비된다면 국민의 생명 신체 및 재산피해는 물론 국가안보에 심각한 위협요인으로 작용할 수 있다. 본 논문에서는 국가기반체계 보호제도에 대한 국내외 동향을 살펴보고 국가운영연속성인 핵심기능연속성의 세부구성 요소인 필수기능, 승계 순서, 권한의 위임, 연속성 시설, 연속성 통신, 중요 기록 관리, 인적 자본, 테스트, 교육 및 훈련, 통제 및 지시 권한이양, 복원에 대하여 구체적으로 알아보고 국가기반 체계 보호계획 관련제도의 분석을 실시하여 구체적인 문제를 살펴보고 효율적인 국가기반체계 보호제도 개선안을 제시하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.57-58
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• 2008

Recently, several kinds of superconductivity applications are implemented and evaluated in the utility power networks. The protection system for HTS(High Temperature Superconducting) power devices safe operation has not been established yet. For the protection of the HTS apparatus, a better understanding of the quench properties against fault current and appropriate protection devices are required. In this study, an algorithm of protection system is developed with respect to HTS power cable. The protection system of HTS power cable was analyzed in the simulated power system. Results obtained from simulation will provide much more decisive data in order to design a certain superconducting power device, and can give a good information for the installation in power system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 정기총회 및 창립40주년기념 학술대회 학회본부
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• pp.454-456
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• 1987

A more specialized area of transient evaluations is transmission line fault-detecting and protection system. During the first cycle or two following a power system fault, a high-speed protective relay is expected to make a decision as to the severity or location of the fault, usually based on 60 Hz information, i.e. the phase and magnitude of 60 Hz voltage or current signals. It is precisely at this time however that the signal is badly corrupted by noise, in the form of a de offset or frequencies above 50 Hz. One of several possible sources of transients in protection measuring signals is in the primary system for which protection is required in its response to the impact of short circuit fault on-set. Other sources are in the primary voltage and current transducers from which protection signals are derived, and, often of particular importance, in the interface circuits between the transducer secondaries and the comparator and measuring elements of the protection system. However, the noise signals that will be described in this paper are due to the main power system only and do not include errors due to current or voltage transducers.

• 전기전자학회논문지
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• 제28권2호
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• pp.204-208
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• 2024

본 논문에서는 ESD 보호회로의 전류구동 특성을 향상시키기 위해 일반적인 저전압용 ESD 보호회로인 LVTSCR의 구조적 변경을 적용한 ESD 보호회로를 제안한다. LVTSCR 구조에서의 electric field와 ESD 전류 경로가 형성 되는 영역을 분리하여 전력 소모를 최소화 하였으며 이에 대한 전기적 특성을 분석하고 전류 구동 특성을 개선하였다. 시뮬레이션을 통한 System-level 특성 저하에 기인하는 구조적인 문제를 분석하였으며 이를 반영하여 특성을 검증하였다. 제안된 ESD 보호회로의 전기적 특성은 TCAD 시뮬레이션을 통해 검증하였으며 HBM 모델링 및 System-level 모델링을 통해 분석하였다. 또한, DB-Hitek사의 0.18um BCD 공정을 통해 silicon 제작 및 HBM 10kV 특성 검증하였다.

• International Journal of Computer Science & Network Security
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• 제21권5호
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• pp.113-120
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• 2021

The adoption of the General Data Protection Regulation (EU) 2016/679 transformed approaches and concepts to the implementation of the personal data protection mechanism in the European Union. Within the EU, almost all countries have adapted a new protection mechanism, which requires a study of the specifics of its use. The article intends to assess the legal provisions of the current mechanism of personal data protection in the EU. The author studied the mechanism of personal data protection under the General Data Protection Regulation (EU) 2016/679 (GDPR) based on the concept of contextual integrity and analysis of EU legislation on personal data protection. The scientific publications for 2016-2020 were reviewed for the formation of ideas of a new personal data protection mechanism in the EU, informative and transparent analysis of legal provisions. The article notes that the personal data privacy and protection is increasing, there is an ongoing unification of the legal status of personal data protection and the formation of a digital market for dissemination, exchange, control, and supervision of data. Cross-border cooperation is part of the personal data protection mechanism. The author proved that the GDPR has changed approach to personal data protection: the emphasis is now shifting to the formation of a digital market, where the EU's role in ensuring regulation is crucial. The article identifies the emergence of a new protectionist legal system and strengthening of legal provisions regarding privacy. This legal system needs unification and harmonization in accordance with national legislation, is territorially fragmented and differentiated within the EU.

• International Journal of Railway
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• 제1권4호
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• pp.149-156
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• 2008

During maintenance or construction works in or at the tracks of railways, high risks for passengers and railway staff, especially for the workers on the construction site exist. The high risks result out of the movement of rail vehicles, like trains or construction vehicles, which must be faced by using any available technical and operational technologies for securing them against the environment. Therefore, it is necessary to evaluate the level of protection continuously and to identify new and innovative methods and technologies for the protection of the gang (construction worker, machines and material). Especially on construction sites at line sections with two or more parallel tracks but also with single tracks, there are still a lot of incidents and accidents mostly with seriously injured persons or fatalities. These were mainly gang members that breach the railway-loading gage. By using proper warning or protection systems, the avoidance of such accidents must be achieved. The latest developments. in gang protection systems concern on the one hand fixed barriers in the middle between the construction site and the operated track and on the other hand construction vehicles equipped with automatic warning systems. The disadvantage of such protection methods is that the gang can be warned against an approaching train but a monitoring of the gang members cannot be performed. Only one part of a potential dangerous situation will be detected. If the gang members will overhear the acoustic warning signal of the security staff and the workers will not leave the danger zone in the track, the driver of the approaching train had no chance to react to the dangerous situation. An accident is often inevitable. While the detection of acoustic warning signals by the gang members working on a construction site is very difficult, the acoustical planning of an automatic warning system has to be designed for an acoustic short range level of one meter besides the construction vehicle. The decision about the use of today's technical warning system (fixed systems, automatic warning systems, etc.) must be geared to the technical feasibility and the level of safety which is needed. Criteria for decision guidance to block a track should be developed by danger estimation and economical variables. To realize the actual jurisdiction and to minimize the hazards of railway operations by the use of construction vehicles near the tracks further developments are needed. This means, that the warning systems have to be enhanced to systems for protection, which monitor the realization of the warning signal as a precondition for giving a movement authority to a train. This method can protect against accidents caused by predictable wrongdoing. The actual state of the art technique of using a collective warning combined with additional security staff is no longer acceptable. Therefore, the Institute of Transportation System of the German Aerospace Center in Braunschweig (Germany) will develop a gang warning and protection system based upon imaging methods, with optical sensors such as video in visible and invisible ranges, radar, laser, and other. The advantage of such a system based on the possibility to monitor both the gang itself and the railway-loading gauge either of the parallel track or of the same track still in use. By monitoring both situations, the system will be able to generate a warning message for the approaching train, that there are obstacles in the track, so that the train can be stopped to prevent an accident. And also the gang workers will be warned, while they breach their area.

• Journal of Electrical Engineering and Technology
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• 제2권2호
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• pp.172-177
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• 2007

Wavelet transforms provide basis functions for time-frequency analysis and have properties that are particularly useful for the compression of analogue point on wave transient and disturbance power system signals. This paper evaluates the compression properties of the discrete wavelet transform using actual power system data. The results presented in the paper indicate that reduction ratios up to 10:1 with acceptable distortion are achievable. The paper discusses the application of the reduction method for expedient fault analysis and protection assessment.

• 방재기술
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• 통권27호
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• pp.11-13
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• 1999