• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2014년도 추계 학술논문 발표대회
• /
• pp.119-120
• /
• 2014

In this study, we looked into the method to establish fire growth rate by buildings use for growing fire at the beginning of a fire considering the characteristics of the combustibles in a performance-based design. Actual conditions survey and literature review were carried out for the fire load and exposed surface area of combustibles to establish design fire by domestic building use. As a results, a simplified prediction equation of fire growth rate which depends on fire load and weight of combustibles could be derived by calculating the relation between the fire load and the fire growth rate of an initial fire through investigation of combustibles by domestic building use.Also, as a result of analyzing the placement of combustibles and location of the ignition source, it was found that the influence of the materials of the combustibles and the materials of the combustibles adjacent to the ignition source is big. Though 4 different experiments were carried out for the evaluation, the result of comparing the findings with those of FGR model showed that the fire growth rate was similarly derived.

• 한국구조물진단유지관리공학회 논문집
• /
• 제20권2호
• /
• pp.122-130
• /
• 2016

최근 수십년간의 산업화로 인해 인간중심의 하천 개발이 이루어진 결과, 하천의 직강화 및 복개화 등 오수 및 하수의 배출구로만 활용되어 집중호우 등의 수해가 반복되어 발생하고 있어 이에 대해 하천 및 제방의 사면을 각종 공법을 통하여 손상을 방지하고 있으나, 관련 기준에서는 비탈높이, 최소비탈경사 등 최소한의 기준만 제시하고 있는 실정이다. 또한 홍수해 방지를 위한 가장 중요한 특성인 소류력에 대한 검토는 전무한 실정이다. 따라서 본 연구에서는 실규모의 인공실험하천에서 다공성콘크리트 호안블록을 설치하고, 유입유량을 조절하여 각 실험조건에 따른 유속 및 수심을 측정하여 소류력을 평가하였다. 다공성콘크리트블록의 압축강도 및 공극률 시험결과 압축강도는 16.6~23.2 MPa의 범위로 측정되었고, 실측공극률은 10.1%로 나타나 국내 기준을 만족하는 것으로 판단되며, 소류력 시험결과 한계소류력은 $47.202N/m^2$으로, 하천설계실무요령에서 제시된 급류부의 소류력 범위인 $67N/m^2$은 만족하지 못하는 것으로 나타났다. 하지만 블록 및 기반층의 유실이나 손상이 전혀 관찰되지 않았고, 기존 선행연구를 참고하여 볼때 그 이상의 소류력에도 저항력을 가질 수 있을 것을 추정하여 볼 수 있다. 따라서 추후 실험조건 등을 조정하여 실질적인 한계소류력 측정을 위한 실험을 다시 수행할 필요가 있다고 판단된다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제52권12호
• /
• pp.602-607
• /
• 2003

We show three-dimensional distribution of voltages resulted from the leakage current originated from outdoor electrical facilities in a submerged area. In case these facilities are grounded by the neutral line multiple grounding method, the existence of ungrounded electrical facilities can cause a disastrous effect on near-by passengers. In order to investigate this situation, we installed a real-scale test field for the experiment type I (for the leakage current path between a enclosure grounded electrical facility and another enclosure grounded one), and that for the experiment type II (for the leakage current path between a enclosure grounded electrical facility and another ungrounded one). For both cases, we carried out three-dimensional monitoring of the voltage distribution while varying additional conditions such as the exposure of the underground cables and the finishing of cable connection part. The result shows that a disastrous effect on human safety can arise from the leakage current without a pertinent measure for the construction and maintenance of outdoor electrical facilities.

• 한국대기환경학회지
• /
• 제11권2호
• /
• pp.145-152
• /
• 1995

Predictability of a Gaussian model, ISCST2 was assessed by scaling up wind tunnel experiments with a 1/3,000 terrain model to the real scale. Concentration profiles obtained from the flat-terrain experiment in the neutral condition were estimated to be in agreement with the calculated ones from ISCST2 in the stability class A, but the difference between the two was still large. Concentration profiles from the mountainous-terrain experiments were better fitted to the calculated ones primarily because in the experiment, concentration behind the source was raised due to the effect of a hill in the upstream side. Model prediction was improved with including the downwash effect of buildings and the hill, but overall concentration profiles were not much different from a typical Gaussian profile. While concentration profiles in the experiments were changed with local flows by varying the wind direction and the topography, those from the Gaussian modeling were mot freely changed together with these variations.

• 한국산학기술학회논문지
• /
• 제13권12호
• /
• pp.6151-6158
• /
• 2012

친환경 하천사업의 활성화로 식생매트의 사용은 증가하고 있으나 수리적 안정성에 대한 평가는 미흡한 실정이다. 본 연구는 호안용 식생매트 제품의 객관적인 수리안정성 시험 기법 개발을 위해 수행하였다. 이를 위해서 식생매트 2종에 대한 실규모 실험을 수행하여 수리량을 측정하고 분석하여 작용 소류력을 계산하였다. 1차원 부정류 모형을 이용하여 최적 조도계수를 결정하고 작용 소류력을 계산하였다. 각 유량의 시험 후에는 매트 표면 및 기반층의 변동 여부를 기록하여 평가하였으며 이에 따라 매트표면의 손상 유형 3가지 및 기반층의 손상 유형 2가지를 제시하였다. 본 연구에서는 식생매트의 표면 변동이 있더라도 하부 기반층의 유실이 발생하지 않는 경우에는 안정한 상태로 제안하였다. 이에 따라 실험체 2종의 허용소류력을 평가하였으며 철망으로 보강된 식생매트가 허용 소류력 측면에서 효과가 있는 것을 확인할 수 있었다.

• 한국건축시공학회지
• /
• 제20권4호
• /
• pp.339-345
• /
• 2020

본 연구는 매년 수만 건 발생되는 화재에서 화재확산에 의한 피해 예방과 대응 마련을 위해 공동주택 및 일반건물의 내부화재를 실물화재실험을 통해 재현하였다. 또한, 개구부 크기와 차양길이 조건을 달리하고 이에 따른 외벽온도 분포를 분석하여 화재확산방지 기초자료를 제공하고자 하였다. 실험결과, 차양을 설치하지 않았을 때 최고온도는 약 380℃ 이상으로 나타났다. 차양을 설치하지 않은 최고온도를 기준으로 차양길이가 150mm 일 때, 동일한 측정점에서 약 90℃가량 낮아졌으며, 300mm에서 약 150℃ 이상, 450mm에서 175℃ 이상 온도가 낮아졌으며, 차양길이 600mm 일 때, 최고온도 차는 약 180℃ 이상 낮아지는 것으로 나타나 개구부 상부의 차양 설치가 외벽의 수직화재 확산에 의한 화염온도를 낮추는데 효과가 있는 것으로 판단된다.

• Structural Engineering and Mechanics
• /
• 제52권5호
• /
• pp.875-887
• /
• 2014

The aim of the shaking table experiment is to verify the isolation effect of a storage liquid tank with multiple friction pendulum bearings. A 1:20 scale model of a real storage liquid tank that is widely used in the petroleum industry was examined by the shaking table test to compare its anchored base and isolated base. The seismic response of the tank was assessed by employing the time history input. The base acceleration, wave height and tank wall stress were used to evaluate the isolation effect. Finally, the influences of the bearing performance that characterizes the isolated tank, such as the friction force and residual displacement, were discussed.

• Journal of Information Processing Systems
• /
• 제11권4호
• /
• pp.643-654
• /
• 2015

Face recognition under controlled settings, such as limited viewpoint and illumination change, can achieve good performance nowadays. However, real world application for face recognition is still challenging. In this paper, we propose using the combination of Affine Scale Invariant Feature Transform (SIFT) and Probabilistic Similarity for face recognition under a large viewpoint change. Affine SIFT is an extension of SIFT algorithm to detect affine invariant local descriptors. Affine SIFT generates a series of different viewpoints using affine transformation. In this way, it allows for a viewpoint difference between the gallery face and probe face. However, the human face is not planar as it contains significant 3D depth. Affine SIFT does not work well for significant change in pose. To complement this, we combined it with probabilistic similarity, which gets the log likelihood between the probe and gallery face based on sum of squared difference (SSD) distribution in an offline learning process. Our experiment results show that our framework achieves impressive better recognition accuracy than other algorithms compared on the FERET database.

• Communications for Statistical Applications and Methods
• /
• 제27권4호
• /
• pp.413-430
• /
• 2020

The multiply Type-II hybrid censoring scheme is disadvantaged by an experiment time that is too long. To overcome this limitation, we propose a generalized multiply Type-II hybrid censoring scheme. Some estimators of the scale parameter of the exponential distribution are derived under a generalized multiply Type-II hybrid censoring scheme. First, the maximum likelihood estimator of the scale parameter of the exponential distribution is obtained under the proposed censoring scheme. Second, we obtain the Bayes estimators under different loss functions with a noninformative prior and an informative prior. We approximate the Bayes estimators by Lindleys approximation and the Tierney-Kadane method since the posterior distributions obtained by the two priors are complicated. In addition, the Bayes estimators are obtained by using the Markov Chain Monte Carlo samples. Finally, all proposed estimators are compared in the sense of the mean squared error through the Monte Carlo simulation and applied to real data.

• 한국생산제조학회지
• /
• 제22권2호
• /
• pp.268-274
• /
• 2013

Electric discharge machining drill (EDM-drill) is an efficient process for the fabrication of micro-diameter deep metal hole. As there is non-physical contact between tool (electrode) and workpiece, EDM-drill is widely used to machine the hard machining materials such as high strength steel, cemented carbide, titanium alloys. The electro-thermal energy forces the electrode to wear out together with the workpiece to be machined. The electrode wear occurs inside of a machining hole. and It causes hard to monitor the machining state, which leads the productivity and the quality to decrease. Thus, this study presents a methodology to estimated the electrode wear amount while two coefficients (scale factor and shape factor) of the logarithmic regression model are evaluated from the experiment result. To increase the accuracy of estimation model, the linear transformation method is adopted using the differences of initial electrode wear differences. The estimation model is verified through experiment. The experimental result shows that within minute error, the estimation model is able to predict accurately.