• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.643-648
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• 1989

This paper presents a theoretic study and computer simulation of models and approaches for dynamical obstacle avoidance by mobile robots. The movement of obstacles in unknown environment is described by any one or a combination of three models. The control strategy of the mobile robots is formulated based on one of three approaches. A trajectory-guided control strategy for dynamical obstacle avoidance has been developed. The method greatly simplifies the control process of mobile robots, and is computationally attractive.

• Journal of the Korean Society of Costume
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• v.21
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• pp.219-226
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• 1993

The main purpose of this study is to inves-tigate brand loyalty on ready-to-wear of fe-male. The subjects were two hundred ninty females in Taegu. Using SPSS package in or-der to identify relations of clothing selection behavior and information source uses multivariate analysis of variance(MANPVA) univariate analysis of variance(ANOVA) were executed. Scheffe est a kind of post-hoc multiple comparisons methods was adapted. conclusions reached in this study are as follows: 1. Clothing purchase pattern of consumers classified brand loyal group and brand dis-loyal group. The number of people in the brand loyal group was fifty more than that of the brand disloyal group. 2. In relation of brand loyalty and clothing selection behavior brand loyal group had high scores on individuality and exhibition of clothing selection behavior. Brand dis-loyal group had high scors on economy practicality courtesy facility. 3. In difference of information uses on brand loyalty brand loyal group had high scores on printed-information source, broadcast-ing-information source broadcast-ing-information sources. Among them brand loyal group particularly used printed-infor-mation source more than brocasting infor-mation source. On the contray brand dis-loyal group have high scores on human-in-formation source.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.907-912
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• 1989

A new procedure is presented for optimally placing closed-loop poles of multivariable continuous-time systems in specified regions via linear-quadratic(LQ) state-feedback design. This method has the advantages of pole-placement and LQ-design. In addition, it provides minimum feedback gains in the control law.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.454-457
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• 1997

The purpose of this study is to develop an optimal model, using existing models, that is able to estimate the amount of spatter utilizing artificial neural network in the short circuit transfer mode of gas metal arc (GMA) welding. The amount of spatter generated during welding can become a barometer which represents the process stability of metal transfer in GMA welding, and it depends on some factors which constitute a periodic waveforms of welding current and arc voltage in short circuit GMA welding. So, the 12 factors, which could express the characteristics for the waveforms, and the amount of spatter are used as input and output variables of the neural network, respectively. Two neural network models to estimate the amount of spatter are proposed: A neural network model, where arc extinction is not considered, and a combined neural network model where it is considered. In order to reduce the calculation time it take to produce an output, the input vector and hidden layers for each model are optimized using the correlation coefficients between each factor and the amount of spattcr. The est~mation performance of each optimized model to the amount of spatter IS assessed and compared to the est~mation performance of the model proposed by Kang. Also, through the evaluation for the estimation performance of each optimized model, it is shown that the combined neural network model can almost perfectly predict the amount of spatter.

• Journal of applied mathematics & informatics
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• v.4 no.2
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• pp.433-446
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• 1997

In this paper we study an existence and the approxi-mation of the solution of the solution of the elliptic variational inequality from an abstract axiomatic point of view. We discuss convergence results and give an error estimate for the difference of the two solutions in an appropriate norm Also we present some computational results by using fixed point method.

• Journal of applied mathematics & informatics
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• v.6 no.2
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• pp.661-668
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• 1999

Reliability estimation using Gibbs sampler considered for modeling mixture exponential reliability problems. Gibbs sampler is developed to compute the features of the posterior distribution. Bayesian estimation of complicated functions requires simpler esti-mation techniques due to the mathematical difficulties involved in the Bayes approach. The Maximum likelihood estimator and the Gibbs estimator of reliability of the system are derived. By simula-tion risk behaviors of derived estimators are compared. model de-termination based on relative error is considered. A numerical study with a simulated data set is provided.

• Journal of applied mathematics & informatics
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• v.2 no.2
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• pp.13-20
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• 1995

The goal of this paper is to show that the linear approxi-mation in evaluation of functions may be effectively replaced by the ex-ponential approximation formulas obtained by numerical quadratures and in the instance the relative errors can be estimated without know-ing the true values.

• Korea Information Processing Society Review
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• v.5 no.1
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• pp.62-74
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• 1998

This paper deals with developing a remote & real-time Computer-Aided Logistics Support (CALS) Systems through Information Super-Highway. A prototype of CALS is designed and implemented considering the environment of Information Super Highway. The concept of CSCW based virtual enterprise is discussed in con-nection with the four different activities. development of remote & virtual equipment controller remote-monitoring & inspection real time tracking of logistics information and web-based bidding and delivery system. A real implemented system is demonstrated under the Infor-mation Super-Highway with the corresponding software and hardware configuration.

• School Mathematics
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• v.4 no.3
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• pp.347-360
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• 2002

This study analyzed the mathematical and didactical contexts of the Euclid's proof about Pythagorean theorem and compared with the teaching methods about Pythagorean theorem in school mathematics. Euclid's proof about Pythagorean theorem which does not use the algebraic methods provide students with the spatial intuition and the geometric thinking in school mathematics. Furthermore, it relates to various mathematical concepts including the cosine rule, the rotation, and the transfor-mation which preserve the area, and so forth. Visual demonstrations can help students analyze and explain mathematical relationship. Compared with Euclid's proof, Algebraic proof about Pythagorean theorem is very simple and it supplies the typical example which can give the relationship between algebraic and geometric representation. However since it does not include various spatial contexts, it forbid many students to understand Pythagorean theorem intuitively. Since both approaches have positive and negative aspects, reciprocal complementary role is required in pedagogical aspects.

• Journal of Ocean Engineering and Technology
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• v.1 no.1
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• pp.33-38
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• 1987

The first order mation responses of a floating structure and the hydrodynamic forces in regular waves are obtained by means of the linear potential theory. The first order potential is obtained directly from the numerical solution of the improved Green integral equation which is characterized by the combined surface distribution of sources and normal doublets. The mean second order wave drift force is also calculated by means of the near field method. It seems that the present method gives more accurate numerical results than other methods and the agreement between numerical and experimental results appears to be satisfactory.