• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.3
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• pp.223-230
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• 2005

Lately, massive concrete structures are increasingly built. Mass concrete structures are cast in many stages with construction joints. Individually constructed segment exhibit different heat source properpies and time dependent properties. As such construction stages must be incorporated in a heat of hydration analysis model to truly reflect a real construction process. Thermal stress analysis is conducted to find the way of controlling the thermal crack of pier footing mat in this paper. The footing mat model fur the analysis is $12m\times14m$ area and 3m height. This study show the process of construction stage and analyzes the results for a foundation structure constructed in 2 stage pours.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.545-548
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• 2008

As the corrosion of reinforcing bar in concrete structures exposed to chloride attack is one of main factors to determine the remaining service life, marine concrete structures have to be designed to protect the chloride penetration. Among the durability design methods such as deterministic method and probabilistic method, design method based on the probabilistic theory has been widely studied. However, the most essential material, data of the material properties related to chloride diffusion, are still insufficient. In this paper, the probabilistic distribution of chloride diffusion coefficients and aging coefficients are derived by the experiment and analysis for the chloride coefficients of concrete containing pozzolans, which are generally used in marine structures.

• Tunnel and Underground Space
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• v.19 no.6
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• pp.558-566
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• 2009

Time-dependent behavior is a basic mechanical property of rocks. Predicting the failure time of rock structures by analyzing the time-dependent characteristic is important and problematic. It is tried to predict the failure time of tunnel, slope & laboratory creep test specimen from measured displacement(or strain) and rate with relationship suggested by Voight($\ddot{\Omega}=A\dot{\Omega}^\alpha$, where $\Omega$ is a measurable quantity such as strain & displacement and A & $\alpha$ are constants). A & $\alpha$ are estimated through applying the nonlinear least square method to the single and double integrated Voight's equations and utilized to predict the failure time. Predicted failure time is in accordance with real one except minor error. Linear inverse rate method applied to creep strain and rate yields a poor linear correlation of data and precision of predicted failure time is not better than methods using strain and rate.

• Journal of the Korean GEO-environmental Society
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• v.16 no.12
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• pp.37-43
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• 2015

Ground characteristics is important in tunnel structure utilizing the strength of underground. In the case of the fault fracture zone such as weak soil conditions exists in the tunnel section and groundwater leaching occurs at the same time, it happens to occur to excessive displacement or collapse of tunnel frequently. Fault fracture zone is an important factor that determines the direction of displacement and the collapse of the tunnel under construction. Behavior of fault fracture zone is determined depending on the size and orientation of the surface portion of the tunnel. If the groundwater occurs in the face of tunnel, groundwater causes displacement and collapse. And the collapse characteristics of tunnel is a major factor in determining that the time-dependent behavior. It is difficult to accurately predict groundwater leaching from the fault fracture zone in the numerical analysis method and analyze the interaction behavior of groundwater and fault fracture zone. Therefore numerical analysis method has limitations the analysis of ground water in the ground which the fault fracture zone and groundwater occurs at the same time. It is required to comprehensively predict the behavior of tunnel and case studies of tunnel construction. Thus, the location of fault fracture zone is an important factor that determines the direction of displacement and the collapse of the tunnel. In this study, behavior characteristics of the tunnel according to the location of the fault fracture was analyzed.

• Tunnel and Underground Space
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• v.27 no.3
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• pp.121-131
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• 2017

We studied the time-dependent behaviors of rock and concrete materials by conducting the static and dynamic long-term strength tests. In particular, acoustic emission(AE) signals generated while the tests were analyzed and used for the long-term stability evaluation. In the static subcritical crack growth test, the long-term behavior and AE characteristics of Mode I and Mode II were investigated. In the dynamic long-term strength test, the fatigue limit and characteristics of generation of AE were analyzed through cyclic four points bending test. The graph of the cumulative AE hits versus time showed a shape similar to that of the creep curve with the first, second and third stages. The possibility for evaluating the static and dynamic long-term stability of rock and concrete is presented from the log - log relationship between the slope of the secondary stage of cumulative AE hits curve and the delayed failure time.

• 한국정보교육학회:학술대회논문집
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• 2004.08a
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• pp.622-630
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• 2004

웹의 활용이 보편화되면서 웹을 통한 자료의 검색이 증가하고 있으나, 웹상의 방대한 자료 중에서 학습자가 꼭 필요한 학습자료를 찾는 것은 쉬운 일이 아니다. 검색엔진을 이용하면 원하는 정보를 어느 정도 찾을 수 있으나 사용자 의존적인 검색엔진의 특성상 결과가 만족스럽지 못한 경우도 있으며 연관이 없는 정보를 필터링하기 위해 최종적인 내용을 찾기까지 많은 시간을 낭비하는 경우가 많다. 이에 털 연구에서는 자원의 의미정보를 구조화하여 정보의 효율적인 검색, 통합, 재사용을 가능하도록 하는 시맨틱 웹 (Semantic Web)기술을 활용하여 초등학교 학습자료에 적합한 온톨로지 (Ontology)를 구축하여 이를 기반으로 초등학교 학습자료를 검색할 수 있는 시스템을 설계하고 구현하였다. 본 검색시스템의 특징은 다음과 같다. 첫째, 학습자료와 연관된 사용자 질의어를 보다 상세하게 입력받는다. 둘째, 사용자 질의어를 바탕으로 온톨로지에 질의하여 검색결과를 얻는다. 셋째, 검색하고자 하는 내용의 의미를 분석하여 요구된 의미에 적합한 자료만을 검색결과로 제시한다.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1993.04a
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• pp.169-169
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• 1993

동물의 일반활동은 중추신경계에 작용하는 약물에 관한 많은 정보를 제공한다. 따라서 약물의 중추신경계에 대한 독성평가는 물론이고 중추신경계 작용약물의 검색에도 널리 이용된다. 본 연구에서는 여러 가지 기전으로 중추신경계에 작용하는 약물들의 일반활동을 분석하여 중추신경계 작용 약물들의 작용기전에 따르는 일반활동의 특성을 비교 분석하고자 하였다. 실험장치는 UGO BASILE제 활동측정 장치를 이용하였으며, 실험동물은 서울대학교 의과대학 실험동물 사육장에서 사육한 ICR mouse를 사용하였다. 동물의 활동측정은 환경요인을 최소한으로 배제하기 위하여 매일 9:00-11:00 까지 2시간 동안의 행동을 10분 간격으로 측정 기록토록 하였다. 중추신경 흥분제 amphetamine, 진정수면제 phenobarbital, 항불안제 diazepam, 항정신병약 chlorpromazine, 항우울제 haloperidol는 모두 용량 의존적으로 동물의 자발운동에 영향을 미쳤다. 특기할 것은 항불안제 diazepam 은 용량의존적으로 운동 억제를 나타내었으나 진정수면제 phenobarbital의 경우는 용량 의존전 운동억제를 나타내기 이전에 초기약물 유발성 aggressive behavior를 나타내었다. 본 실험결과는 동물의 자발행동의 분석으로 중추신경계 작용약물의 작용기전 규명 및 이에 따르는 약물의 분류 방법으로 유용하게 이용될 수 있을 것으로 생각된다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.01a
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• pp.45-48
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• 2022

IoT 기술의 발전 및 확산으로 다양한 도메인에서 서로 다른 특성의 시계열 데이터가 수집되고 있다. 이에 따라 단일 목적으로 수집된 시계열 데이터만 아니라, 다른 목적으로 수집된 시계열 데이터들 또한 통합하여 분석활용하려는 수요 또한 높아지고 있다. 본 논문은 파편화된 시계열 데이터들을 선택하여 통합한 후 딥러닝 모델을 생성하고 활용할 수 있는 해시함수 기반 학습 모델 관리 플랫폼을 설계하고 구현하였다. 특정되지 않은 데이터들을 기반하여 모델을 학습하고 활용할 경우 생성 모델이 개별적으로 어떤 데이터로 어떻게 생성되었는지 기술되어야 향후 활용에 용이하다. 특히 시계열 데이터의 경우 학습 데이터의 시간 정보에 의존적일 수밖에 없으므로 해당 정보의 관리도 필요하다. 본 논문에서는 이러한 문제를 해결하기 위해 해시 함수를 이용해서 생성된 모델을 계층적으로 저장하여 원하는 모델을 쉽게 검색하고 활용할 수 있도록 하였다.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.709-712
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• 2008

RC super tall buildings are planned and constructed recently in domestic area. Concrete is characterized by time dependant material such as creep and shrinkage. For this properties of concrete, differential shortening is one of the main issues on super tall buildings construction. This study includes material research, which is performing as a pre design stage to solve differential shortening on Lotte Super Tower Jamsil core structure(50, 60, & 70 MPa). The major part of this study is composed with comparison and analysis between experimental data and predicted data on total shrinkage and total compliance which were used on design stage. Four models, ACI209R Model, Ba${\check{z}}$ant-Baweja B3 Model, CEB MC99 Model, & GL2000 Model, were employed to predict them. It also tries to seek a proper model for high strength and high performance concrete in the case of no concrete test.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.6
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• pp.66-71
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• 2009

This paper presents the grounding impedance behaviors of counterpoise exposed to impulse currents. The transient and conventional grounding impedances of three counterpoises having the length of 10, 30 and 50[m] were measured and analyzed as a function of the injection point of impulse currents. As a result, the trend of the conventional grounding impedances measured as a function of injection of impulse current is similar to the transient grounding impedance of counterpoise. The injection point of impulse current has great influence on the transient grounding impedance characteristics of counterpoise. The transient grounding impedance characteristics in a short time range are strongly dependent on the length of counterpoise. The transient characteristics of grounding impedance of 10[m] counterpoise subjected to the impulse current was capacitive behavior, on the other hand, those of 30[m] and 50[m] counterpoises were inductive behavior. It is found that the grounding conductor should be connected to the central point of counterpoise.