• Journal of Biosystems Engineering
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• 제18권4호
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• pp.402-409
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• 1993

During all mechanical processes rice plants are subjected to verious forces such as natural load of wind and mechanical load of agricultural machines. A force is always accompanied by deformation, which must be either sufficiently great for pressing or sufficiently slight in order to avoid damage. The mechanical behavior of the rice plants is determined by three variables : force, deformation and time. And they must be studied using rheological methods to determine their viscoelastic properties. This study is conducted to experimentally determine the mechanical and rheological properties of the rice stalks subjected to radial load. The force relaxation tests are performed under constant deformation, during which the reduction of forces over time is measured. The mechanical models were developed from the abtained data. The results were as follows : 1. The relaxation behavior of a rice stalk in radial compession may be described by a generalized Maxwell model consisting of 3 Maxwell elements in parallel. 2. Relaxatiom intensity always decreased with increased time of relaxation. 3. The rate of deformation has a significant effect on the relaxation behavior. having increasing pattern with an increase in rate of deformation. 4. The relaxation intensity and residual deformation increased with increased initial load. 5. The relaxtion of the intermediate portion of stalk was bigger tham that of the upper and lower portions.

• 한국전산구조공학회논문집
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• 제13권4호
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• pp.461-473
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• 2000

이 논문은 콘크리트의 크리프와 건조수축 현상을 고려한 강재와 콘크리트의 부분 합성보의 거동의 해석을 위한 모델을 제안하고 있다. 부분합성 거동은 선형 부분전단 연결이론을 토대로 합성보를 일정한 수의 요소로 분할한 후 각 절점에서 평형조건과 적합조건을 기초로하여 구성 방정식을 구성하고 경계조건과 각 요소에 대한 구성 방정식을 순차적으로 적용하는 방법으로 해석모델이 구성되었다. 또한 콘크리트의 시간에 따른 현상인 크리프와 건조수축의 영향도 고려되었다. 제안된 해석모델은 다경간 연속 합성보의 슬립거동을 효과적으로 나타낼 수 있다. 제안된 해석 모델의 검증을 위해 기존 연구의 결과와 비교되었으며, 여러 조건에 대한 합성보의 해석을 통해 제안된 모델의 적용성을 입증하였다.

• 한국지진공학회논문집
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• 제20권5호
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• pp.301-310
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• 2016

There are differences in seismic behavior between non-skewed bridges and skewed bridges due to in-plane rotations caused by pounding between the skewed deck and its abutments during strong earthquake. Many advances have been made in developing design codes and guidelines for dynamic analyses of non-skewed bridges. However, there remain significant uncertainties with regard to the structural response of skewed bridges caused by unusual seismic response characteristics. The purpose of this study is performing non-linear time history analysis of the bridges using abutment-soil interaction model considering pounding between the skewed deck and its abutments, and analyzing global seismic behavior characteristics of the skewed bridges to assess the possibility of unseating. Refined bridge model with abutment back fill, shear key and elastomeric bearing was developed using non-linear spring element. In order to evaluate the amplification of longitudinal and transverse displacement response, non-linear time history analysis was performed for single span bridges. Far-fault and near-fault ground motions were used as input ground motions. According to each parameter, seismic behavior of skewed bridges was evaluated.

• Geomechanics and Engineering
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• 제18권3호
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• pp.299-313
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• 2019

This research investigated the nonlinear compressibility, permeability, the yielding due to structural degradation and their effects on consolidation behavior of structured soft soils. Based on oedometer and hydraulic conductivity test results of natural and reconstituted soft clays, linear log (1+e) ~ $log\;{\sigma}^{\prime}$ and log (1+e) ~ $log\;k_v$ relationships were developed to capture the variations in compressibility and permeability, and the yield stress ratio (YSR) was introduced to characterize the soil structure of natural soft clay. Semi-analytical solutions for one-dimensional consolidation of soft clay under time-dependent loading incorporating the effects of soil nonlinearity and soil structure were proposed. The semi-analytical solutions were verified against field measurements of a well-documented test embankment and they can give better accuracy in prediction of excess pore pressure compared to the predictions using the existing analytical solutions. Additionally, parametric studies were conducted to analyze the effects of YSR, compression index (${\lambda}_r$ and ${\lambda}_c$), and permeability index (${\eta}_k$) on the consolidation behavior of structured soft clays. The magnitude of the difference between degree of consolidation based on excess pore pressure ($U_p$) and that based on strain ($U_s$) depends on YSR. The parameter ${\lambda}_c/{\eta}_k$ plays a significant role in predicting consolidation behavior.

• 대한건축학회논문집:계획계
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• 제35권9호
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• pp.41-48
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• 2019

Recently as the rapid increasing of the elderly, silver housing has grown up. Though much fire evacuation and safety law, fire accident is most dangerous problem in our society. So this study is the purpose to analyze evacuation safety in urban silver housing of floor planning by corridor types using human behavior simulation. The methodology of this study is 'Literature Review' and 'Simulation'. This study has been carried out on silver housing's definition, types, fire safety theory and relation law. To proof evacuation safety, this study measured escaping time, longest distance, and bottleneck counting using human behavior simulation. This study use game engine simulation program to analyze 6 corridor types experimental model. As the result of simulation, this study compare between ASET and simulation result. The result come down to 3 part. First, double loaded corridor type is the most dangerous on urban silver housing. Second, Safe shelter's location and number cause increasing of escaping time. Lastly escaping time is influenced by behavior of agent, bottle neck strike frequency.

• Structural Engineering and Mechanics
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• 제83권3호
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• pp.401-413
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• 2022

The collapse of civil infrastructure due to natural disasters results in financial losses and many casualties. In particular, the recent increase in earthquake activities has highlighted on the importance of assessing the seismic performance and predicting the seismic risk of a structure. However, the nonlinear behavior of a structure and the uncertainty in ground motion complicate the accurate seismic response prediction of a structure. Artificial intelligence can overcome these limitations to reasonably predict the nonlinear behavior of structures. In this study, a deep learning-based algorithm was developed to estimate the time-history seismic response of bridge structures. The proposed deep neural network was trained using structural and ground motion parameters. The performance of the seismic response prediction algorithm showed the similar phase and magnitude to those of the time-history analysis in a single-degree-of-freedom system that exhibits nonlinear behavior as a main structural element. Then, the proposed algorithm was expanded to predict the seismic response and fragility prediction of a bridge system. The proposed deep neural network reasonably predicted the nonlinear seismic behavior of piers and bearings for approximately 93% and 87% of the test dataset, respectively. The results of the study also demonstrated that the proposed algorithm can be utilized to assess the seismic fragility of bridge components and system.

• 한국식품저장유통학회지
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• 제31권2호
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• pp.199-209
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• 2024

This study explored how temperature, time, and moisture content affect the rheological properties (apparent viscosity, flow behavior index, and consistency coefficient) of stored tomato and pepper purees. These purees were prepared with moisture contents of 85%, 90%, and 95% (w/v) using the hot-break method and tested over 6 days at 2-day intervals and temperatures of 5℃, 10℃, and 15℃. Results displayed distinct ranges for apparent viscosity, consistency coefficient, and flow behavior indices: tomato puree (2,519.9-4,324.6 mPa·s, 258.0-550.6 mPa·Sn, 1.80-0.48) and pepper puree (2,105.6-4,562.0 mPa·s, 268.4-580.4 mPa·Sn, 0.22-0.48). The temperature and storage time had significant (p≤0.05) effects, but moisture content did not affect these properties. Flow behavior and consistency coefficients demonstrated relative variation with apparent viscosity, indicating pseudoplastic behavior. Optimal processing and storage conditions were identified within specific ranges: 13.21-14.42℃ for 2 days with 92.22-94.23% (w/v) moisture content for pepper, and 8.42-11.77℃ for 2-6 days with 85% (w/v) moisture for tomato.

• 대한수학회지
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• 제37권5호
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• pp.721-733
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• 2000

A paeabolic-elliptic system modelling chemotaxis is analysed. We study the behavior of solutions, especially the finite-time blowup of nonradial dolutions, to parabolic-elliptic system of n(n 2).

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제10권2호
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• pp.41-47
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• 2006

The Renewal process and the Non-homogeneous Poisson process (NHPP) process are probably the most popular models for describing the failure pattern of repairable systems. But both these models are based on too restrictive assumptions on the effect of the repair action. For these reasons, several authors have recently proposed point process models which incorporate both renewal type behavior and time trend. One of these models is the Modulated Power Law Process (MPLP). The Modulated Power Law Process is a suitable model for describing the failure pattern of repairable systems when both renewal-type behavior and time trend are present. In this paper we propose Bayes estimation of the next failure time after the system has experienced some failures, that is, Mean Time Between Failure for the MPLP model. Numerical examples illustrate the estimation procedure.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.149-151
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• 2001

In real-time control system, it is essential to confirm the timing behavior of all tasks because these tasks of real-time controller have to finish their processes within the specified time intervals called a deadline. In order to satisfy this objective, the timing analysis of a real-time system such as a schedulability test must be performed during the system design phase. This paper presents a Matlab toolbox for simulation of real-time control system based on OSEK-OS, which is one of the most widely adopted real-time operating systems in automotive industry. The toolbox allows the user to explore the timely behavior of control algorithms, and to study the interaction between the object of the OSEK-OS, such as task, scheduler and resource etc.