• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 C
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• pp.1452-1454
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• 1997

Properties of flashover in polymer insulators are very important under pollution environments. It is necessary to analyse flashover characteristics whether insulators are still safe or not. A lot of precious information can be got out of polluted polymer insulators through leakage current measurement. The behavior of partial arc discharge leads to flashover directly. It is possible to measure partial arc discharge as leakage current pulses analysis. The shape of histogram reflects degree of pollution, wetting and voltage stress level. It can be expressed by Weibull distribution function.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.384-389
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• 2008

In this paper, we propose a UML modeling of ATO on-board software. An automatic train operation (ATO) system is a real-time control system, which operates a train without a manual operation by a driver. For the safe and comfortable service, real-time embedded software for ATO on-board equipment should have both of high performance and reliability. UML-based object-oriented modeling technique is introduced and used widely to design software that satisfies this requirement. We used Rhapsody, which is a modeling tool for real-time embedded software, to model the construction and the behavior of ATO on-board equipment. As a result, ATO on-board software which performs the profile calculation and the real-time speed control is designed and implemented. The brief modeling result including behavioral characteristics and the simulation results are presented.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1999년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall
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• pp.3-14
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• 1999

The Hyogoken-Nambu Earthquake of January 17, 1995 inflicted severe damage in the Hanshin and Awaji areas such as has never been seen in Japan in recent years. The safety inspections of the dams conducted in the area by site offices and dam experts immediately after the earthquake showed that there was no damage affecting the safety of the dams although slight damage was observed in several dams. The investigation also revealed that the peak accelerations at dam sites were much smaller than those at soil sites. The Ministry of construction organized the Committee on Evaluattion of Earthquake Resistance of Dams after the earthquake. The Committee confirmed through dynamic analysis that the dams designed in accordance with the present design criteria in Japan are safe under the magnitude of shaking that occurred close the source fault of the Hyogoken-Nambu Earthquake.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2008년도 춘계학술대회
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• pp.19-33
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• 2008

The study on semiconductor industrial accident in korea has been focused on frequencies of each type, employee, characteristics, cause and un-safety condition, behaviour and so on. Those attributes of semiconductor industrial accidents were usually analyzed independently, so that it was hard to provides a well-process and systematic guide lines for efficient safety management. There fore, there were a few studies based on comprehensive survey in terms of sharp-type of safe management. The questionnaire survey carried out for the workers(284) who were responsible for safety management in to center with corporate company with semiconductor industry the factor analysis showed that there were three factor of safety management. They were 1) Investment and operation and management for accident prevention, 2) Unsafe, safety management 3) General human error and behavior the industries of respondents were correlative with three group. Three Groups showed a statistically significant differences on the number of cases. Actually, the group with the larger investment and the better unsafe cause, human error a of accident prevention had a smaller cause of accident cases.

• ETRI Journal
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• 제28권5호
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• pp.555-560
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• 2006

A PIN photodiode having a low dark current of 1.35 nA and a high external quantum efficiency of 95.3% fabricated for a passive optical network receiver. As the current was increased under a high voltage of 38 V and a temperature of $190^{\circ}C$, it was observed that there is a threshold current at 11 mA which induces a junction failure. Experimental data suggest that the junction failure occurs due to the crystal breaking at the end facet as a result of thermal heat or energetic carriers. This threshold behavior of junction failure is a valuable observation for the safe treatment of photodiodes. As long as the current is limited below the threshold currents, we have not observed failure events of our photodiodes.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 봄 학술발표회 논문집
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• pp.475-482
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• 1997

This study reports the results of flexural test on 6 specimens for maximum reinforcement ratio and 4 specimens for minmum reinforcement ratio with concrete compressive strength 1,000, 1,200 kg/$\textrm{cm}^2$ . The major test variables for the reinforcement ratio designed 0.55$\rho_b$, 0.65$\rho_b$, 0.75$\rho_b$ for maximurm reinforcement ratio test 14/fy $\sqrt[0.72]{\rho}\acute{f}_c$ / $f_y$ for minimum reinforcement ratio test. The test results were compared with ACI 318-95 Code. In the Ultra High Strength Concrete beam, the maximum reinforcement ration should be less than 0.6$\rho_b$ for ductile behavior and the existing minimum reinforcement ratio by ACI Building Code is Sufficiently safe.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(I)
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• pp.475-478
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• 2005

This study was performed to evaluate about load bearing capacity of continuos IPC Girder Bridge under and after Construction. This is Ichi-1 Bridge that is 2-40m span continuous bridge on a extension road through the Ichun and the Naesa. The result of static loading test to use a 25ton truck after construction, deflection ratio is 0.64 that is $35\%$ and average of response ratio is 0.48$\~$0.89 that is less than theoretical value. The result of dynamic loading test, the number of proper vibrations is 3.06Hz that is like theoretical value 3.61Hz, the modulus of impact is 0.235 that is bigger than specification 0.19. the load bearing capacity is minimum DB-40 that is so big value. In the result, continuos IPC Girder Bridge is safe in short period. we will evaluate long period behavior of continuos IPC Girder Bridge.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 가을 학술발표회 논문집
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• pp.65-84
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• 2002

The Observational Method proposed by Terzaghi can be applied for the safe and economic construction projects where the exact prediction of the behavior of the structures is difficult as in the underground excavation. The method consists of measuring lateral displacement, ground settlement and axial force of supports in the earlier stage of the construction and back analysis technique to find the best fit design parameters such as earth pressure coefficient, subgrade reaction etc, which will minimize the gap between calculated displacement and measured displacement. With the results, more reliable prediction of the later stage can be obtained. In this study, back analysis programs using the Direct Method, based on the Hill Climbing Method were made and evaluated, and to overcome the limits of the method, Genetic Algorithm(GA) was applied and tested for the actual construction cases.

• 한국초전도ㆍ저온공학회논문지
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• 제7권3호
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• pp.1-4
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• 2005

As high temperature superconductor applications became a reality due to increase in coated conductor performance, it is important to understand their stability behavior to design safe electrical power systems. Coated conductors can be stabilized with different metals and alloys for different types of application, to yield excellent electrical, thermal and mechanical performance. We have experimentally studied the dependence of quench and recovery characteristics of stainless steel stabilized coated conductors on the amplitude of current and duration time. Stability test of 3cm long sample were performed in a liquid nitrogen bath cooling condition by applying a short period over current pulses for 50 and 100ms, with amplitude up to ~6 times the critical current. The transport current that flows before and after the current pulse was fixed at about ~80-85% critical current. We analyzed the quench and recovery phenomena of the test sample using the current voltage characteristic.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2008년도 정기총회 및 학술발표대회
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• pp.333-336
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• 2008

U-Channel Bridge is effective bridge type, because its edge beam performs role of barrier and enables to reduce additional dead loads. Nevertheless, there is possibility of bridge collapse under impact load due to car crash. Also, edge beam must have ability to induce safe driving and prevent falling accidents. Therefore, this study carries out analysis of behavior of edge beam and slab and evaluation of structural stability under impact loads, based on Korean Highway Bridge Design Specifications and AASHTO LRFD Bridge Design Specification. According to analysis result, the maximum stress of edge beam and slab satisfies specification of allowable stress.