• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.11
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• pp.2871-2882
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• 1994

Two kinds of 4-node plane stress/strain finite elements are presented in this work. They are derived from the modified Hellinger-Reissner variational principle so as to employ the internal incompatible displacement and independent stress fields, or the incompatible displacement and strain fields. The introduced incompatible functions are selected to satisfy the constant strain condition. The elements are evaluated on several problems of bending and material incompressibility with regular and distorted elements. The results show that the new elements perform excellently in the calculation of deformation and stresses.

• The Korean Journal of Applied Statistics
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• v.22 no.5
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• pp.1007-1017
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• 2009

Forecasting for air demand such as passengers and freight has been one of the main interests for air industries. This research has mainly focus on the comparison the performance between the univariate seasonal ARIMA models and the multivariate time series models. In this paper, we used real data to predict demand on international passenger and freight. And multivariate time series models are better than the univariate models based on the accuracy criteria.

• Journal of the Korean Institute of Telematics and Electronics
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• v.16 no.5
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• pp.27-33
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• 1979

It is reported that a typical multivariable system of chemical process type was constructed and control experiment was conducted using a $\mu$-computer instead of using conventional hardwave controller. When the pressure of water to be supplied to the multivariable system is varying, an adaptive control method using a flowmeter is suggested to enhance the control performance.

• The Transactions of the Korean Institute of Power Electronics
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• v.2 no.1
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• pp.1-11
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• 1997

In this paper, a novel multivariable state feedback control with feedforward control is proposed to improve control performance of power conversion systems. The targets of the application are three-phase voltage-source PWM converter and inverter system, and current-source PWM converter and inverter system, of which equivalent circuits and models are derived and analyzed. Various simulation results are presented to verify the validity of the proposed scheme.

• Proceedings of the KIEE Conference
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• 1986.07a
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• pp.212-214
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• 1986

• ICROS
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• v.5 no.4
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• pp.14-20
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• 1999

• Proceedings of the KIEE Conference
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• 1984.07a
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• pp.52-54
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• 1984

• Journal of KIISE:Software and Applications
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• v.29 no.3
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• pp.156-166
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• 2002

Decision tree induction is a kind of useful machine learning approach for extracting classification rules from a set of feature-based examples. According to the partitioning style of the feature space, decision trees are categorized into univariate decision trees and multivariate decision trees. Due to observation error, uncertainty, subjective judgment, and so on, real-world data are prone to contain some errors in their feature values. For the purpose of making decision trees robust against such errors, there have been various trials to incorporate fuzzy techniques into decision tree construction. Several researches hove been done on incorporating fuzzy techniques into univariate decision trees. However, for multivariate decision trees, few research has been done in the line of such study. This paper proposes a fuzzy decision tree induction method that builds fuzzy multivariate decision trees named fuzzy oblique decision trees, To show the effectiveness of the proposed method, it also presents some experimental results.

• Geotechnical Engineering
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• v.12 no.4
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• pp.61-74
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• 1996

Settlement induced by low -level vibration on granular soils is too complect to predict with one or two fact ors. Factors affecting vibration induced settlement were investigated, and a settlement prediction model on granular soils was developed using multifactorial experimental design(MED). Factors such as vibration amplitude, deviatoric stress, confining pressure, soil gradation, duration of vibration, moisture content, and relative density were considered in this study. A special vibratory frame was designed to shake a soil specimen within a triaxial cell. MED allowed the authors to investigate the effect of many factors using a relatively small number of experiments. The most significant factors on settlement were vibrati on amplitued, confining pressure, and defiatoric stress. Comparable settlement was occurred even under low-level vibration ranging from 2.5 to 18mm1sec, and stress am sotropy was found to be an important factor on settlement.

• Water for future
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• v.27 no.3
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• pp.55-69
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• 1994

In order to enhance the short-term flood forecasting accuracy of the water level of the In-do Brdg., three statistical flood forecasting models are presented models are presented and the forecasting accuracies and stabilities of the models are studied. The presented statistical models are as follows: The multi-input model by the multi-regression analysis between the water level of the In-do Brdg. and the influence parameters(Model MM). The two-level multi parameter model according to the water level tendency(Model 2MP). Among the three models, the Model MM showed the lowest forecasting accuracy, the model 2MP showed the highest forecasting accuracy, although this model sometimes became unstable and diverged. The model MMP forecasted the flood less accurately than model 2MP, but it gave more stable forecasting results.