• Korean Journal of Construction Engineering and Management
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• v.21 no.1
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• pp.87-98
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• 2020

As the construction industry accounts for 28.5% of industrial accidents in Korea and 29.6% of industrial accident deaths in 2017, it is necessary to search for a priority disaster reduction scheme for the construction industry in order to reduce the industrial accident rate. Therefore, this research suggested improvement direction for construction accidents reduction based on factors affecting construction accidents occurring in the construction site by DEMATEL analysis. As a result of the analysis, the 4M factors with the highest Prominence and Relation is 'Management', and the detailed analysis of the 4M factors were Personal characteristics of workers, Defects such as machinery and equipment, Inadequate inspection of machinery and equipment, Insufficient safety management plan, Inappropriate work orders from supervisors and field managers. The analysis results of this research can be used as a basic data for establishing direction of reduction and improvement of construction accidents.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1656-1664
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• 2007

This paper introduces a study of improvement for a defect diagnosis of the UM71C track circuit using on HSL. The track circuit on HSL has long operation section. Therefore, when the worker maintain, many times and efforts are spent. So, periodically, we have operated a inspection car. However, we don't know exactly the state changed of the inspection data when track circuit has defect. Actually, We fixed a sample area within operation section on HSL and performed the simulations for short circuit current that is reflected characteristic impedance and propagation factor. We compared the measuring data with the result of the simulation. Using verified simulation program, we estimated inspection data as the malfunction number and the change of capacity of compensation capacitor. These study need to secure of the safety as the train operation. Also, It needs to make a criteria of analysis for the maintenance through comparison simulation data and inspection data.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2007.11a
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• pp.288-293
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• 2007

미국 911 테러 발생 이후로, 국가 기반시설(예: 송/배전 전력망, 석유/가스 파이프라인, 원자력 발전소, 정보통신 시설, 교통 시설, 금융 시설, 매스미디어 시설 등)에 대한 테러리스트의 사보타지 리스크를 관리하는 도전문제에 정부 차원이나, 기업 차원에서 국내외적으로 뜨거운 이목이 집중되고 있다. 그 가운데 에너지 시스템, 특히 원자력 발전소의 물리적 보안은 국가 안보 차원에서 매우 중대한 이슈가 되고 있다. 이는 사보타지로 인한 이러한 시스템의 파손이 국민, 작업자, 또는 외부 환경에 방사성물질 누출과 같은 중대한 결말을 초래할 수 있기 때문이다. 원전과 같은 복잡 시스템에서 설계 기준 위협이 초래할 수 있는 이러한 결말은 그 시스템의 특정 핵심 표적(예: 부품, 구역, 자산, 행위, 인원)의 방호를 통해 효과적으로 방어될 수 있다. 다시 말하면, 표적 인식에서는 어떻게 방어할 것인가에 앞서서 무엇을 방어할 것인가를 다루려는 것이다. 이 연구의 주요 목적은 여태까지 개발된 다양한 표적 인식 기법의 개발 추세를 소개하고 향후 전망을 제시하는 데에 있다. 이를 통해 표적 인식 기법의 수월성, 신뢰성, 및 경제성을 제고할 수 있으리라 본다. 표적 인식 기술의 활용성 측면에서 볼 때, 표적 인식은 하드웨어 적이거나 소프트웨어적인 방호 시스템의 설계에 필수적이므로, 신뢰성 높은 표적 인식은 다음과 같은 긍정적인 파급 효과를 줄일 수 있다: 1) 사보타지 리스크 감소에 직간접적으로 기여할 수 있다; 2) 제한적인 보안 재원을 효율적으로 할당할 수 있다; 3) 보안 대응군대의 훈련 시나리오를 개발할 수 있다; 4) 발전소 규제요건인 안전조치 계획을 비용이나 보안 측면에서 향상시켜 국민 안심(public easiness)을 도모할 수 있다. 향후에는 보다 더 광의적인 복잡 시스템 사이에서 상호 연계적인 사보타지에 대한 표적 인식의 기법들이 점검될 필요성이 있다고 본다.

• Fire Science and Engineering
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• v.16 no.3
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• pp.8-11
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• 2002

Recently, the spark and the overheat due to in the failure of pressure contacts on connecting points and the momentary short circuit have been the major causes of electrical fire because these may cause the deposition and the graphite of insulating materials in electrical wiring system. Also, because in these cases the current is a surge one, the losses and faults of a communication, a home appliances, a computer and a measuring instrument may occur. Especially, in such cases, we are very difficult to detect the failure of pressure contacts on connecting points and the momentary short circuit. In this paper, we have developed an auxiliary control device, the electrical fire prevention control device(EFPCD), of an earth leakage breaker(ELB). And we can pre-vent the electrical fire caused by the spark and the overheat occurring in the failure of pressure contacts in connecting points and the momentary short circuit with the EFPCD.

• The Journal of the Korea Contents Association
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• v.16 no.1
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• pp.362-369
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• 2016

Recently, Last to check the security status of various medium and large bridge structures using various kinds of measurement equipment, but most of the methods are used to measure and check the displacement behavior of the bridge by a certain period. In this study, receive GPS satellite signals that can be observed in real time the whole region, a bridge to automatically measure the displacement and behavior characteristics of the structure in real-time in mm over the 24 hours, the measurement information and transmits the data to the wireless network, by making use, it was applied to the real-time monitoring system in connection with a bridge to be able to automatically notify GNSS fine displacement behavior. In fact, analysis and receives the measurement data to GNSS provided in the upper bridge of the middle and large-sized aging for this purpose, measuring USN and at the same time is converted into a three-dimensional position information of a test study was conducted to monitor the bridge displacement in real time. As a result, a vertical displacement of about 0.027~0.037m at the measurement time of day of the measurement point is that the repeated and confirmed.

• Journal of Advanced Navigation Technology
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• v.19 no.1
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• pp.22-32
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• 2015

Ground based augmentation system (GBAS) is a next generation radio navigation aids to support precision approach of aircraft. Recently, airports installing GBAS and providing GBAS service are increasing all over the world. For the first time in Korea, SLS-4000 which is the GBAS ground equipment of Honeywell had been installed at Gimpo International Airport in 2013, and evaluated its functionality and performance of through the ground testing. This paper introduces a ground test and evaluation criteria on the CAT-I GBAS system, and describes testing methods for GBAS ground testing of Gimpo International Airport. In addition, detail testing methods and analysis results on major five of 12 ground test items are described.

• Journal of Korea Water Resources Association
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• v.48 no.3
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• pp.159-167
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• 2015

Low-level outlets are necessary to empty reservoir storage in case of emergency such as abrupt storage level rise due to storm, dam body inspection as well as initial reservoir storage filling. However, the Korean standard for low-level outlet should be complemented. In this study, the HEC-ResSim model is utilized to simulate and calculate the capacity of the outlets and the days of release in order to evacuate reservoir storage safely. Three cases are analyzed according to its capacity. As a large dam with more than $1,000{\times}106m^3$ total capacity, Soyanggang Dam is selected and as a medium dam between $100{\times}106m^3$ and $1,000{\times}106m^3$ total capacity, Habcheon Dam is selected. Finally as a small dam with a total capacity less than $100{\times}106m^3$, Daegok Dam is selected. The size of low-level outlet and days of storage evacuation is estimated and the applicability of the analysis method is studied.

• Journal of Korean Society for Geospatial Information Science
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• v.13 no.2 s.32
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• pp.45-50
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• 2005

Recently, slope failures are disastrous when they occur in mountainous area adjoining highways. The accidents associated with Slope failures have increased due to rapid urbanization of mountainous area. Therefore, the inspection of slope is conducted to maintain road safety as well as road function. In this study, we apply to the remedy which is comparing existent description to advanced technology using GIS. we utilize a 3D scanner, one of the advanced method, to generate precise and complete road slope model from expert point of view. In result, we are transferred practical data from external slope stability to hazard slope information. We suggest not only the database but also the method of road risk evaluation based on GIS.

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.4
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• pp.436-441
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• 2011

A TPMS is a wireless communication system designed to monitor its condition inside the pneumatic tires on various types of vehicles. These systems report the tire pressure information to the driver of the vehicle. While wireless communications is used to transmit the measurement data from TPMS sensors to a central processing unit in the vehicle, it suffers from the various interferences such as sensors of each tire or outside electrical equipments. Based on the conventional beamformer, a switching beamforming technique is proposed to minimize the interference and efficiently receive valid data. Moreover, in order to minimize the interference and reduce power consumption for communication, a system with unique Gold Code is presented for each tire. The performance of interference suppression is illustrated by computer simulations.

• Composites Research
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• v.16 no.5
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• pp.7-14
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• 2003

Modeling of thick composite structures for finite element analysis is relatively complicated. 2-D plane elements may cause inaccurate result since the plane stress condition cannot be applicable in these structures. Therefore a 3-D modeling should be used. However, the difficulty to model all the layers with different material properties and ply orientation arise in this case. In this paper, an equivalent modeling is proposed and numerically tested for analysis of thick composite structures. By grouping layers with same material and ply orientation, number of elements through the thickness is remarkably reduced and still the result is close enough to the one from a detail finite element model. MSC/NASTRAN and PATRAN are used for the analysis. The proposed modeling technique has been applied for analysis of composite rotor hub system designed by Korea Aerospace Research Institute(KARI). Using the proposed equivalent modeling technique, we could conduct stress analysis for the hub system and check the safety factor of each part.