• Industrial Engineering and Management Systems
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• 제13권3호
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• pp.297-303
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• 2014

Stock pre-positioning is one of the most important decisions for preparing the stage of emergency logistics planning. In this paper, a mixed integer model for stock pre-positioning is derived to support an emergency disaster relief response against the event of earthquake. A maximum response time limit, budget availability, multiple item types, and capacity restrictions are considered. In the model, the decision of the distribution centers to cover a disaster area and the amount of supplies to be stocked in each distribution center are simultaneously determined to maximize the total expected relief demand of the disaster areas covered by the existing distribution centers. The proposed model is applied to a real case with 33 disaster areas and 16 distribution centers in Indonesia. Several sensitivity analyses are conducted to estimate the fluctuation on the emergency stock pre-positioning planning by changing the maximum response time and budgets.

• 품질경영학회지
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• 제7권2호
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• pp.22-28
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• 1979

The problem considered in this paper is to select the vital factor effect to the product quality through the experimental design and analysis of response surface, so as to control the quality improvement of industrial product. In this time, even through the mathematical model is unknown it could be applicable to control the quality of industrial products and to determine optimum operating condition for many technical fields, particulary, for industrial manufacturing process. When a set of data is available from an experimental design, it is often of interest 1:0 fit polynominal repression model in independent variables (eg, time, temperature, pressure, etc) the optimize the response variable (eg. yield, strength etc). This paper proposes a method known to obtain the optimum operating condition, and how to find the condition by using table of orthogonal array experiments, and optimization methodology of statistical model. A criterion can be applied determining to optimum operating conditions in manufacturing industry and improving the fit of response surface which may be used for prediction of responses and quality control of industrial products.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.308-313
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• 2003

Thermal mass flow meters (TMFMs) are most widely used for measuring mass flow rates in the semiconductor industry. A TMFM should have a short response time in order to measure the time-varying flow rate rapidly and accurately. Therefore it is important to study transient heat transfer phenomena in the sensor tube of a TMFM that is the most critical part in the TMFM. In the present work, a simple numerical model for transient heat transfer phenomena of the sensor tube of a TMFM is presented. Numerical solutions for the tube and fluid temperatures in a transient state are obtained using the proposed model and compared with experimental results to validate the proposed model. Based on numerical solutions, heat transfer mechanism in a transient state in the sensor tube is explained. Finally, a correlation for predicting the response time of a sensor tube is presented. The correlation is verified by experimental results.

• Geomechanics and Engineering
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• 제24권2호
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• pp.193-203
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• 2021

The time-history finite element analysis is usually used to evaluate the seismic response of shallow foundations. However, the literature lacks studies on the influence of the soil constitutive model complexity on the seismic response of shallow foundations. This study, thus, aims to fill this gap by investigating the seismic response of shallow foundation resting on dry silica sand using the linear elastic (LE) model, elastic-perfectly-plastic (EPP) model, and hardening soil with small strain stiffness (HS small) model. These models have been used because it is intended to compare the results of a soil constitutive model that accurately captures the seismic response of the soil-structure interaction problems (which is the HS small model) with simpler models (the LE and EPP models) that are routinely used by practitioners in geotechnical designs. The results showed that the LE model produces a very small seismic settlement value which is approximately equal to zero. The EPP model predicts a seismic settlement higher than that produced using the HS small model for earthquakes with a peak ground acceleration (PGA) lower than 0.25 g for a relative density of 45% and 0.40 g for a relative density of 70%. However, the HS small model predicts a seismic settlement higher than the EPP model beyond the aforementioned PGA values with the difference between both models increases as the PGA rises. The results also showed that the LE and EPP models predict similar trend and magnitude of the acceleration-time relationship directly below the foundation, which was different than that predicted using the HS small model. The results reported in this paper provide a useful benchmark for future numerical studies on the response of shallow foundations subjected to seismic shake.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 B
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• pp.930-932
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• 1999

Recently a new modified Smith predictor is proposed for a time-delay system with an integrator. It is shown that the approximate model yields the zero-steady state error and the disturbance compensator improved the transient response. But in case of mismatch between the plant's time-delay and model's time-delay, the overall response is not satisfactory. In this paper, it is proposed that the proper pole is added to the new modified smith predictor to improve the overall response.

• Structural Engineering and Mechanics
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• 제54권4호
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• pp.809-827
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• 2015

In this paper, seismic energy response of inelastic steel structures under earthquake excitations is investigated. For this purpose, a numerical procedure based on nonlinear dynamic analysis is developed by considering material, geometric and connection nonlinearities. Material nonlinearity is modeled by the inversion of Ramberg-Osgood equation. Nonlinearity caused by the interaction between the axial force and bending moment is also defined considering stability functions, while the geometric nonlinearity caused by axial forces is described using geometric stiffness matrix. Cyclic behaviour of steel connections is taken into account by employing independent hardening model. Dynamic equation of motion is solved by Newmark's constant acceleration method in the time history domain. Energy response analysis of space frames is performed by using this proposed numerical method. Finally, for the first time, the distribution of the different energy types versus time at the duration of the earthquake ground motion is obtained where in addition error analysis for the numerical solutions is carried out and plotted depending on the relative error calculated as a function of energy balance versus time.

• 한국화재소방학회논문지
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• 제10권4호
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• pp.13-18
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• 1996

구획화재에서 스프링클러 작동순간의 연층온도와 연층높이를 구하는 모델링 방법을 기술하였다. 스프링클러 작동모델에서의 시정수는 실험으로부터 얻어진 RTI(Response time index)와 스프링클러 주위의 유속을 평가할 수 있는 실험식으로부터 구하였고, 시간에 따른 연층온도 변화는 기존의 2층 zone model을 이용하였다. 모델에 의한 계산결과를 검증하기 위하여 가솔린 pool 화재를 이용한 실험을 수행하여 계산결과와 실험결과를 비교하였다. 본 연구의 결과인 스프링클러 작동순간의 연층온도와 높이는 스프링클러 분무와 화재 Plume의 상호작용을 해석하기 위한 필요한 입력자료로 사용할 수 있다.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2012년도 제45회 KOSCO SYMPOSIUM 초록집
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• pp.5-7
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• 2012

This study presents relations between the time lag and interaction index of the impinging-jet injectors using time lag model in a model chamber. To analyze the response of the flame, 5% amplitude of oxidizer velocity is artificially perturbed at a resonance frequency. At the mixing point of fuel and oxidizer, which determines the characteristic length, the relationship between velocity perturbation and heat release rate is quantified by combustion parameters of interaction index and time lag. As the improved method to apply the time-lag, the method using the average velocity obtained from numerical results is suggested.

• Earthquakes and Structures
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• 제3권2호
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• pp.97-115
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• 2012

The energy-transmitting boundary, which is used in the well-known finite element method (FEM) program FLUSH, is quite efficient for the earthquake response analysis of buildings considering soil-structure interaction. However, it is applicable only in the frequency domain. The author proposed methods for transforming frequency dependent impedance into the time domain, and studied the time domain transform of the boundary. In this paper, first, the estimation methods for both the halfspace condition under the bottom of the soil model and the pseudo three-dimensional effect were studied with the time domain transmitting boundary. Next, response behavior when using the boundary was studied in detail using a practical soil and building model. The response accuracy was compared with those using viscous boundary, and the boundary that considers the excavation force. Through these studies, the accuracy and efficiency of the proposed time domain transmitting boundary were confirmed.

• 인터넷정보학회논문지
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• 제22권3호
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• pp.53-58
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• 2021

보안관제 분야의 실제 업무활동에 대해서는 거의 연구가 없는 실정이다. 이에 본 논문에서는 보안관제의 위협정보 탐지 대응시간 모델링을 통해 적정 투입인력 규모 산정에 기여하고 최신 보안솔루션 투입시의 효과성 분석 등에 활용할 수 있는 실질적인 연구 방법론을 제시하고자 한다. 보안관제센터에서 수행하는 전체 위협정보 탐지대응시간은 TIDRT(Total Intelligence Detection & Response Time)로 정의한다. 전체 위협정보 탐지 대응시간(TIDRT)는 내부 위협정보 탐지대응시간(IIDRT, Internal Intelligence Detection & Response Time)과 외부 위협정보(EIDRT, External Intelligence Detection & Response Time)의 합으로 구성된다. 내부위협정보 탐지대응시간(IIDRT)는 다섯 단계의 소요시간의 합으로 계산할 수 있다. 본 연구의 궁극적인 목표는 보안관제센터의 주요한 업무활동들을 수식으로 모델링하여 보안관제센터의 사이버 위협정보 탐지대응시간 계산식을 산정하는데 있다. 2장에서는 선행연구를 살펴보고, 3장에서는 전체 위협정보 탐지대응시간의 계산식을 모델링한다. 4장에서 결론으로 끝을 맺는다.