• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.2
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• pp.187-194
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• 2014

In this paper, we analyze the outage probability of macro diversity combining in cellular networks in consideration of aggregate interference from other mobile stations (MSs). Different from existing works analyzing the outage probability of macro diversity combining, we focus on a diversity gain attained by selecting a base station (BS) subject to relatively low aggregate interference. In our model, MSs are randomly located according to a Poisson point process. The outage probability is analyzed by approximating the multivariate distribution of aggregate interferences on multiple BSs by a multivariate lognormal distribution.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.4
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• pp.31-38
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• 2021

In this paper, we proposed an optimal design for determining the shape of a lifting lug freely by applying a multivariate function to the D-type lug, which is commonly used in shipyards. We derived the optimal aspect ratio of the lug through structural analysis and analyzed the safety and behavior of the lug aspect ratio. As a result, two types of final candidates, both lighter than the existing lug weight, were suitable for the ratio. They were found to have the greatest force at an angle of 45 degrees when a load of 100 tons was imposed. When the horizontal and vertical feature ratio of the lug was 1:3, it showed excellent results in terms of safety rates while maintaining weight reduction and functional aspects.

• Journal of the Korean Data and Information Science Society
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• v.28 no.5
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• pp.1179-1189
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• 2017

In this study, we propose an alternative method for discriminant analysis using a multivariate empirical distribution function to express multivariate data as a simple one-dimensional statistic. This method turns to be the estimation process of the optimal threshold based on classification accuracy measures and an empirical distribution function of data composed of classes. This can also be visually represented on a two-dimensional plane and discussed with some measures in ROC curves, surfaces, and manifolds. In order to explore the usefulness of this method for discriminant analysis in the study, we conducted comparisons between the proposed method and the existing methods through simulations and illustrative examples. It is found that the proposed method may have better performances for some cases.

• Proceedings of the Safety Management and Science Conference
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• 2005.11a
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• pp.300-310
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• 2005

Mahalanobis Taguchi System (MTS) is developed by Genishi Taguchi as a part of his quality engineering methodology. The basic idea of Taguchi's quality engineering is looking for the way of effectiveness of analyzing multivariate system. In the MTS, with the standardized variables of healthy normal data, Mahalanobis Distance(MD) calculated and that can be discriminate between normal and abnormal objects. If this discrimination process is successful, next step is optimization which is try to reduce number of attributes by neglecting less effective attributes to MD. Orthogonal Array (OA) and Signal to Noise ratio (S/N) are used to evaluate the amount contribution of each attribute to the MD. Wisconsin Breast Cancer study, from machining learning repository at University of California at Irvine, used for examining the discriminant ability of MTS.

• Management Science and Financial Engineering
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• v.6 no.1
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• pp.1-19
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• 2000

This papeer proposes a general approach of the multivariate expontially weighted moving average(MEWMA) chart, in which the smoothing matrix has full elements instead of only diagonal elements. The average run length (ARL) properties of this scheme are examined for a diverse set of quality control environments and the information to design the chhart is provied. Performance of the scheme is measured by estmating ARL and compared to those of two group cumulative sum (CUSUM) chats. The comparison resullts show that the MEWMA chart can improve its ARL performance in detecting a small shifts out-of-control in the start-up stage, the general MEWMA chart of a full smoothing matrix appears to offer an exceptional protection aginst departures from control in the process mean.

• The Korean Journal of Applied Statistics
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• v.7 no.2
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• pp.145-157
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• 1994

For multivariate distributions satisfying stochastic ordering, we suggest maximum likelihood estimation with incomplete data via an EM algorithm. In this paper we restrict our attention to the contingency tables with partially cross-classified observations. We may use the existing isotonic regression program to implement EM algorithm, and we illustrate the estimation process through an example.

• International Journal of Reliability and Applications
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• v.9 no.1
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• pp.7-15
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• 2008

The dimensional measurement equipment, such as Coordinate Measurement Machine (CMM), Optical Coordinate Measurement Machine (OCMM), and Checking Fixture (CF), take multiple dimensional measurements for each part in an automobile industry. Measurements are also recorded under different measurement systems to see if the responses differ significantly over these systems. Each measurement system (CMM, OCMM, and CF) will be considered as different treatments. This set-up provides massive amounts of process data which are multivariate in nature. Therefore, the multivariate statistical analysis is required to analyze data that are dependent on each other. This research provides step by step methodology for the evaluation procedure of the compatibility of measurement systems and clarify a systematic analyzation among the different measurement system's compatibility followed by number of case studies for each methodologies provided.

• Proceedings of the Korean Society for Quality Management Conference
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• 1998.11a
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• pp.325-332
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• 1998

In the context of total quality management, customer satisfaction is a key factor of success. Customer needs have been in the past described with rather vague words. In order to lead in the competitive market, product designers must be willing to interpret and reflect customer perceptions of a product on the design. The objective of this research is to develop a systematic process capable of linking customer preferences on a product to the design of product elements or specifications. The design process consists of multivariate statistical analyses, semantic differentials, and multidimensional scaling techniques under the framework of a methodology known as quality function deployment which is frequently used to construct a quality design process. The process being established is expected to serve as an effective means to communicate between the customer and the designer through proper representational schemes of design elements.

• Journal of Korean Society for Quality Management
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• v.27 no.3
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• pp.142-153
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• 1999

In the context of total quality management, customer satisfaction is a key factor of success. Customer needs have been in the past described with rather vague words. In order to lead in the competitive market, product designers must be willing to interpret and reflect customer perceptions of a product on the design. The objective of this research is to develop a systematic process capable of linking customer preferences on a product to the design of product elements or specifications. The design process consists of multivariate statistical analyses, semantic differentials, and multidimensional scaling techniques under the framework of a methodology known as quality function deployment which is frequently used to construct a quality design process. The process being established is expected to serve as an effective means to communicate between the customer and the designer through proper representational schemes of design elements.

• Journal of the Korea Safety Management & Science
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• v.6 no.1
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• pp.187-199
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• 2004

To suggest a more efficient way of delivering information for process control under computerized environment, population stereotypes of colors were tested with 57 Korean subjects. The subjects were asked to associate 11 colors salient at electronic video displays with 55 pairs of adjectives that might be used when they explain the current state of process. The levels of association were evaluated with semantic differential methods by 7 point scales. Based on the multivariate analyses, the 55 pairs of adjectives were grouped into three distinct dimensions. The emotional maps of the 11 colors with respect to each dimension were presented. The Quantitative relationships between the colors and subjective impressions were also calculated by quantification theory I. On the basis of these color associations, it was suggested a general guideline for color coding when delivering process information