• Journal of the Korean Institute of Navigation
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• v.16 no.3
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• pp.65-76
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• 1992

An algorithm to determine the optimum nominal value of geometrical and material parameters in divice modelling is proposed. The algorithm uses the yield and variance prediction formula and Monte-Carlo analysis. The performance specification of the noise figure must also be satisfied. In this paper, the total number of considered devices is 1000, and each parameter of geometrical and material parameters is generated randomly within the limits of ${\pm}3%$ of nominal value, and the distribution of 1000 geometrical and material parameters is gaussing distribution.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2000.11a
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• pp.195-198
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• 2000

Sliding mode control method is popularly used for robustness to distrurbance and variance of systems internal parameter. However, one of the serious problem of this method is Chattering which occurs in neighborhood of sliding manifold. Another problem is that we cannot expect robustness before system starts sliding mode. A new tuning method of sliding manifold which changes the parameter of sliding manifold dynamically using Wavelet Neural Network is proposed in this paper. We can expect the better performance in sliding mode control by the wavelet neural networks excellent property of approximating arbitrary function for multi-resolution analysis and decrease chattering drastically.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.5
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• pp.117-122
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• 1994

Well-trained neural networks have low sensitivity to input errors. Also, the sensitivity to weigh errors must be considered when implementing neural networks with hardware of limited precision. In this paper, we derive the sensitivity of the Madaline to weight perturbation or input errors in terms of the trained weights, the input pattern, and the variance of weight perturbation or the probability of input errors. The result is verified with a simulation of the Madaline recognizing handwritten digits.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1991.10a
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• pp.115-118
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• 1991

In this paper we derived the asymptotic distribution of the MUSIC null-spectrum, from which an exact expression of the asymptotic variance of the MUSIC null-spectrum can be obtained. From this result in addition an explicit expression of the normalized standard deviation (NSD) has been derived and it is shown that the NSD is affected by the number of sensors and the number of signals.

• Communications for Statistical Applications and Methods
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• v.2 no.1
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• pp.48-54
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• 1995

A direct method for fitting analysis-of-variance models to unbalanced data is presented. This method exploits sparsity and rank deficiency of the matrix and is based on Gram-Schmidt orthogonalization of a set of sparse columns of the model matrix. The computational algorithm of the sum of squares for testing estmable hyphotheses is given.

• ETRI Journal
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• v.22 no.4
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• pp.51-65
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• 2000

In this paper, we investigate on the determinants of new venture performance empirically and suggest a new venture performance model in the Korean Information and Telecommunications (IT) industry. A total of seven hypotheses is established and tested using a combination of factor analysis, cluster analysis, analysis of variance, and correlation analysis. Ninety-two sample ventures in the Korean IT industry were investigated and analyzed to test hypotheses. We found that new ventures performance depends on their environment, strategy, internal resources factors, and, most importantly, two-way and three-way interactions of these factors. These findings could be interpreted as supporting the general strategy theory that when environment and internal resources and fitted, performance might be maximized and, further, strategy is the means that make internal resources and environment fit. The venture performance model presented in this paper can explain how new ventures achieve their successes. The strategic implications to the venture firms are also discussed.

• Journal of the Korean Home Economics Association
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• v.42 no.6
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• pp.103-110
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• 2004

Among accessaries, headwear is important to protect one's face and head from the sun, wind and cold. This study was performed to provide fundamental data on college female students' head shape by classifying their head shapes and by analyzing the characteristics of each head shape in order to improve the fitness of headwear. The subjects were 193 Korean college female students. The subjects were directly measured anthropometrically and indirectly analyzed photo-graphically. By direct and indirect measurement, 5 factors were extracted through factor analysis and those factors comprised 76.34% of the total variance. 3 clusters as their head shape were categorized using 5 factor scores by cluster analysis. Type 1 was characterized by long head type and having smallest head thickness and head girth. Type 2 had average size and the most round-head type. Type 3 was characterized by short head type and the largest head thickness and head girth.

• Fashion & Textile Research Journal
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• v.4 no.1
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• pp.40-46
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• 2002

The purpose of this study was to classify the clothing purchasing behavior of department store credit card users according to fashion lifestyle. The questionnaire was administrated to 346 female department store credit card users aged over 20 living in Daegu, Frequency factor analysis, cluster analysis, one-way Analysis of Variance (ANA), MANOVA, Scheffe test, ${\chi}^2$-test and t-test were used for satistical analysis. The consumers' lifestyle was classified by fashion oriented, practical and self conspicuous. The results showed that the credit card users' clothing purchasing behavior was different according to the fashion lifestyle. The self conspicuous group showed the highest score in impulse buying.

• Journal of the Korea institute for structural maintenance and inspection
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• v.2 no.4
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• pp.194-200
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• 1998

Risk, probability of failure, which includes various uncertainties and influential factors of performance should be accounted for in engineering system. Recently, several different methods to analysis risk evaluation evolved and one of the practical method is FOSM (First Order Second Moment Method ). FOSM method is derived in terms of terms coefficient of variance to uncertainties which influence various factor. For risk evaluation and uncertainty analysis in hydraulic design system, load-capacity relationship is adopted in this paper. Sample catchment with design of sewer system is applied, which plots safety factor vs. risk. Risk evaluation and uncertainty analysis are very to important develop optimal design model in hydraulic system

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.773-778
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• 2002

The variance characteristics of the calcium carbonate contents along to the concrete cover depth takes the prediction method of remaining service life of concrete. Calcium carbonate contents were measured by the Thermo Gravimetric/Differential Thermal Analysis method at three point, depth of 0.25cm, 0.75cm, 1.25cm from the surface of concrete. This prediction method contain some assumption that the chemical protection conferred on steel is through a passive protective oxide film which forms on steel in an environment at or above a pH of 10.5$^{4)}$ .