• Journal of the Korea Society for Simulation
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• v.29 no.2
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• pp.119-127
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• 2020

This study numerically investigated a structural behavior subjected to consecutive explosions. To this end, a small scale one-way reinforced slab (RC) with fixed-fixed boundary condition was considered as the target structure, and a commercial software, LS-DYNA, was utilized for finite element (FE) analysis. Prior to performing FE analysis, preliminary tests were carried out to verification of a computational model for the one-way RC slab. In the numerical simulation, identical blast loads were consecutively applied to the structure, and cumulative damage assessment were carried out based on its maximum dynamic displacements. As a result of the numerical simulation, it was found that maximum displacements considering permanent deformation due to a prior explosion were almost linearly increased in every explosion until the hazardous damage threshold.

• Proceedings of the Korea Multimedia Society Conference
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• 2001.11a
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• pp.115-120
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• 2001

본 논문에서는 비닐 튜브의 결함검사에 이용하기 위한 이진화 임계치의 자동 결정방법과 패턴매칭에 이용되는 패턴 모델의 자동 친정방법에 대하여 기술한다. 256 Gray 영상을 받아 들여 이진화 임계치를 결성하기 위해서, 휘도치 분포 곡선에서 2개의 극대값을 찾고, 두 극대 위치의 중간위치를 이진화 임계치로 결정하는 방법을 이용하였다. 그리고 패턴 모델을 생성하기 위하여는 수직, 수평 방향의 누적함(Profile)을 이용하였다. 이 방법은 인쇄물 검사 시스템뿐 아니라 비슷한 휘도치 분포를 같는 반도체 자동 검사 시스템을 비롯한 일반적인 건사 시스템에 적용이 가능하다.

• Korean Journal of Construction Engineering and Management
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• v.23 no.5
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• pp.108-116
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• 2022

Started in 1989 as Public Permanent Rental Housing scheme, public rental housing lease policy is increasing target residents and supply in each government by introducing new supply types. However, public housing business entities have difficulties in expanding the supply due to cumulated deficit. The research suggested long-term public rental housing reconstruction business as a method to preserve the cumulated deficit from the previous. Minimum floor area ratio mathematical model was suggested by defining the floor area ratio of reconstruction business as minimum, since housing sales profit after reconstruction could preserve aggregated deficit, and mathematically approached by considering the traits of long-term public rental housing reconstruction. The determinant for minimum floor area ratio mathematical model comprise cumulated deficit of the existing long-term public rental housing, land size of reconstructed sale housing, housing sales price per unit area, and business cost per unit area. Minimum floor area ratio mathematical model is expected to be the milestone for supporting decision making regarding the economic part of old long-term public lease housings' reconstruction scale, and expanding housing supply within urban area.

• Fire Science and Engineering
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• v.30 no.2
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• pp.92-97
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• 2016

The present study has been conducted to estimate the chemical flame height based on fuel consumption in fire field model. The calculation algorithms based on cumulative fraction of HRRPUL and fuel concentration along the z axis were applied to the results predicted by Fire Dynamics Simulator (FDS) version 6.3.2 and the mean chemical flame height was obtained by time averaging of instantaneous flame height with the algorithms. The mean flame height calculated by fuel concentration was quite well matched with that of cumulative value of HRRPUL within 10% over-prediction. This study contribute to a more detailed understanding of fire behavior and quantitative evaluation of flame height in the computational fire model.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.3
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• pp.6-21
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• 2008

We have investigated the effect of the forward and reverse ESD pulse accumulation on the development of the oxide VCSEL's electrical and optical characteristics. The forward ESD-induced degradation is complicated, showing three degradation phases with increasing ESD voltage while the reverse ESD-induced degradation is divided by a sudden distinctive change in elecorl-optical characteristics. By comparing the measured L-I-V characteristics and their derivatives with the fitted characteristics using an equivalent circuit model as well as the large signal circuit model, the development of the oxide VCSEL's electro-optical characteristics under forward and reverse ESD conditions has been fully understood.

• Journal of the Korean GEO-environmental Society
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• v.22 no.10
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• pp.31-36
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• 2021

Estimation of accumulated rotational angles and settlements are critical in design of wind turbine foundation. However, there have been few exploring the response of bucket foundation to long-term cyclic loading. We performed a series of three-dimensional finite element analyses of bucket foundations installed in sands. An empirical formulation which captures the stiffness degradation observed in cyclic triaxial tests implemented into the finite element analysis in the form of a user subroutine. Using the stiffness degradation model the accumulated rotation and displacement of bucket foundation were calculated. Additionally, important factors affecting the response under cyclic loading were assessed.

• Annual Conference on Human and Language Technology
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• 2020.10a
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• pp.421-426
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• 2020

다중 도메인 목적 지향 대화에서 기존 딥 러닝을 이용한 대화 상태 추적(Dialog state tracking)은 여러 턴 동안 누적된 사용자와 시스템 간 대화를 입력 받아 슬롯 밸류(Slot value)를 추출하는 모델들이 연구되었다. 하지만 이 모델들은 대화가 길어질수록 연산량이 증가한다. 이에 본 논문에서는 다중 도메인 대화에서 누적된 대화의 history 없이 슬롯 밸류를 추출하는 방법을 제안한다. 하지만, 단순하게 history를 제거하고 현재 턴의 발화만 입력 받는 방법은 문맥 정보의 손실로 이어진다. 따라서 본 논문에서는 도메인 상태(Domain state)를 도입하여 매 턴 마다 대화 상태와 함께 추적하는 모델을 제안한다. 도메인 상태를 같이 추적함으로써 현재 어떠한 도메인에 대하여 대화가 진행되고 있는지를 파악한다. 또한, 함축된 문맥 정보를 담고 있는 이전 턴의 대화 상태와 도메인 상태를 현재 턴의 발화와 같이 입력 받아 정보의 손실을 줄였다. 대표적인 데이터 셋인 MultiWOZ 2.0과 MultiWOZ 2.1에서 실험한 결과, 대화의 history를 사용하지 않고도 대화 상태 추적에 있어 좋은 성능을 보이는 것을 확인하였다. 또한, 시스템 응답과 과거 발화에 대한 의존성을 제거하여 end-to-end 대화 시스템으로의 확장이 좀 더 용이할 것으로 기대된다.

• The Transactions of the Korea Information Processing Society
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• v.7 no.12
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• pp.3821-3828
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• 2000

Many software projects collect grouped failure data (failures in some failure interval or in variable time interval) rather than individual failure times or failure count data during the testing or operational phase. This paper presents the neural network (NN) modeling that is dble to predict cumulative failures in the variable future time for grouped failure data. ANN's predictive ability can be affected by what it learns and in its ledming sequence. Eleven training regimes that represents the input-output of NN are considered. The best training regimes dre selected rJdsed on the next' step dvemge reldtive prediction error (AE) and normalized AE (NAE). The suggested NN models are compared with other well-known KN models and statistical software reliability growth models (SHGlvls) in order to evaluate performance, Experimental results show that the NN model with variable time interval information is necessary in order to predict cumulative failures in the variable future time interval.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.1A
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• pp.142-155
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• 2000

In this paper, we propose an efficient policing mechanism for Markov model-based traffic descriptors of VBR MPEG video traffic. A VBR video sequence is described by a set of traffic descriptors using a scene-basedMarkov model to the network for the effective resource allocation and accurate QoS prediction. The networkmonitors the input traffic from the source using a proposed new policing method. for policing the steady statetransition probability of scene states, we define two representative monitoring parameters (mean holding andrecurrence time) for each state. For frame level cell rate policing of each scene state, accumulated average cellrates for the frame types are compared with the model parameters. We propose an exponential bounding functionto accommodate dynanic behaviors during the transient period. Our simulation results show that the proposedpolicing mechanism for Markovian traffic descriptors monitors the sophisticated traffic such as MPEG videoeffectively and well protects network resources from the nalicious or misbehaved traffic.

• Proceedings of the KIEE Conference
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• 1997.07b
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• pp.571-574
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• 1997

항법장치의 핵심요소인 가속도센서와 자이로센서는 선형거리추측(Linear position estimation)과 각 변위 추측(orientation estimation)시 출력 데이터에 포함된 오차성분의 적분에 의하여 시간이 증가함에 따라 선형거리 오차와 각 변위 오차가 누적된다. 이에 따라 본 논문에서는 정밀한 항법을 위한 저가의 IMU (Inertial Measurement Unit)를 설계하고, 오차성분의 사전해석을 통하여 정확한 오차모델을 찾는데 그 목적이 있다.