• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.633-636
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• 2006

Impact damage modeling of concrete under high strain rate loading conditions is investigated. A phenomenological penetration model that can account for complicated impact and penetration process such as the rate and loading history response of concrete, the microstructure-penetration interaction etc. is discussed. Constitutive law compatible with Second Law of thermodynamics and coupled damage and plasticity modelling based on continuum damage mechanics are also examined. The purpose of this paper is preliminarily to study with respect to impact and penetration models for concrete before the development of that model.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.131-135
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• 1991

A quantization error model is suggested for analog to frequency(A/F) converter in strapdown inertial navigation system(SDINS),which is characterized by some white noise exciting the state variables. Also, effects on the performance of SDINS by analog to digital(A/D) converter and A/F converter are analyzed and compared via covariance simulation. As a result, A/F converter turns out to be superior to the A/D converter with respect to the induced navigation error and the difficulty in circuit realization. The quantization error model developed in this paper appears to be useful for optimal filter design.

• Transactions of the Korean Society of Mechanical Engineers
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• v.11 no.4
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• pp.663-667
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• 1987

The conventional model of the heat engine involves the inconsistency with the real engine that the power becomes to be zero at the maximum effectiveness condition. In order to improve this defect, a new model of the heat engine is proposed, in which the heat loss from the heat source is taken into account. In accordance with this model, both the power and effectiveness have their respective extremum with respect to operating conditions, and the effectiveness always becomes to be zero when the power is zero.

• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.441-448
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• 2003

Refraction tomography requires an algorithm for efficiently computing the traveltimes and their $Fr\'{e}chet$ derivatives. We have attempted to solve the damped wave field using the frequency domain finite element model ing and then invoked the reciprocity theorem to calculate the $Fr\'{e}chet$ derivative of the traveltime with respect to the subsurface parameter. Then, we used a damped least square method to invert the traveltimes of the Marmousi 2 model. Numerical tests demonstrate that the refraction tomography with large aperture data can be used to estimate the smooth velocity model for the prestack depth migration.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.3 no.3
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• pp.55-58
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• 1980

Today, L.P. model has often been used in solving economic and managemental phenomena. But in case of adopting L.P. model in dealing with practical economic and managemental problems there is a possibility that we have difficulties in solving these problems because of greatness of model size, cost for collecting data, cost for adjusting matrix, and etc. In this respect "Decomposition Algorithm for L.P." has been used in overcoming the difficulties above stated. In this paper therefore, I will try to introduce and them criticize Dantzig -Wolfe's "Decomposition Method" and Kornai - Liptak's "Two - Level Planning".ot;Two - Level Planning".uot;.

• Journal of the military operations research society of Korea
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• v.16 no.2
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• pp.43-55
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• 1990

When people choose one way of action from various alternatives, they make value judgement. Due to limited capacity of human information processing, however, a decision maker cannot reflect his true subjective utility in evaluating alternatives especially for a problem which has multiattribute. The analytic hierachy model is a tool which converts scores derived from pairwise comparison with respect to each attribute to overall scores of the alternatives. Then the overall scores are utilized to choose an alternative. Therefore this model can be used to support people's value judgement.

• Journal of the Korean Data and Information Science Society
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• v.6 no.1
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• pp.53-61
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• 1995

This paper deals with problems of predicting, based on the random censored sampling, a future observation and the p-th order statistic of n' future observations for the Rayleigh model. We consider the prediction intervals for the Rayleigh model with respect to an inverse gamma prior distribution. In additions, numerical examples are given in order to illustrate the proposed predictive procedure.

• Communications of the Korean Mathematical Society
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• v.23 no.1
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• pp.141-151
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• 2008

In this paper, we derive the nonlinear equation for European option pricing containing liquidity risk which can be defined as the inverse of the partial derivative of the underlying asset price with respect to the amount of assets traded in the efficient market. Numerical solutions are obtained by using finite element method and compared with option prices of KOSPI200 Stock Index. These prices computed with liquidity risk are considered more realistic than the prices of Black-Scholes model without liquidity risk.

• ETRI Journal
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• v.36 no.5
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• pp.704-713
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• 2014

Most natural language processing tasks depend on the outputs of some other tasks. Thus, they involve other tasks as subtasks. The main problem of this type of pipelined model is that the optimality of the subtasks that are trained with their own data is not guaranteed in the final target task, since the subtasks are not optimized with respect to the target task. As a solution to this problem, this paper proposes a consolidation of subtasks for a target task ($CST^2$). In $CST^2$, all parameters of a target task and its subtasks are optimized to fulfill the objective of the target task. $CST^2$ finds such optimized parameters through a backpropagation algorithm. In experiments in which text chunking is a target task and part-of-speech tagging is its subtask, $CST^2$ outperforms a traditional pipelined text chunker. The experimental results prove the effectiveness of optimizing subtasks with respect to the target task.

• Journal of Environmental Science International
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• v.20 no.1
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• pp.119-126
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• 2011

In this study, reaction model and reactions rate accelerated by o-iodosobenzoate ion(IB$^{\ominus}$) on hydrolysis reaction of p-nitrophenyl valate(NPV) using ethyl tri-octyl ammonium mesylate(ETAMs) for quaternary ammonium salts, the phase transfer catalysis(PTC) reagent, were investigated. The effect of IB$^{\ominus}$ on hydrolysis reaction rate constant of NPV was weak without ETAMs solutions. Otherwise, in ETAMs solutions, the hydrolysis reactions exhibit higher first order kinetics with respect to the nucleophile, IB$^{\ominus}$, and ETAMs, suggesting that reactions are occurring in small aggregates of the three species including the substrate(NPV), whereas the reaction of NPV with OH$^{\ominus}$ is not catalyzed by ETAMs. Different concentrations of NPV were tested to measure the change of rate constants to investigate the effect of NPV as substrate and the results showed that the effect was weak. This means the reaction would be the first order kinetics with respect to the nucleophile. This behavior for the drastic rate-enhancement of the hydrolysis is referred as 'Aggregation complex model' for reaction of hydrophobic organic ester with o-iodosobenzoate ion(IB$^{\ominus}$) in hydrophobic quarternary ammonium salt(ETAMs) solutions.