• Communications for Statistical Applications and Methods
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• v.18 no.3
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• pp.377-389
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• 2011

A higher quality level is generally perceived by customers as improved performance by assigning a correspondingly higher satisfaction score. The third generation index $C_{pmk}$ is more powerful than two useful indices $C_p$ and $C_{pk}$ that have been widely used in six sigma industries to assess process performance. In actual manufacturing industries, process capability analysis often entails characterizing or assessing processes or products based on more than one engineering specification or quality characteristic. Since these characteristics are related, it is a risky undertaking to represent the variation of even a univariate characteristic by a single index. Therefore, the desirability of using vector-valued process capability index(PCI) arises quite naturally. In this paper, we consider more powerful vector-valued process capability index $C_{pmk}$ = ($C_{pmkx}$, $C_{pmky}$)$^t$ that consider the univariate process capability index $C_{pmk}$. First, we examine the process capability index $C_{pmk}$ and plug-in estimator $\hat{C}_{pmk}$. In addition, we derive its asymptotic distribution and variance-covariance matrix $V_{pmk}$ for the vector valued process capability index $C_{pmk}$. Under the assumption of bivariate normal distribution, we study asymptotic confidence regions of our vector-valued process capability index $C_{pmk}$ = ($C_{pmkx}$, $C_{pmky}$)$^t$.

• Journal of Distribution Science
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• v.13 no.8
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• pp.97-104
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• 2015

Purpose - This study examines the positive impact of the social distance between producers and users of online content, investigating and analyzing the most popular Web content. In addition, it tries to elicit the matching effect that appears when the individuals'cultural background is consistent with social distance. Research design, data, and methodology - We collected and analyzed actual data about 4,981 videos clips on YouTube, looking at six countries in order to verify the content of this study. Based on the results of the data analysis, the study conducted behavioral measurements on popularity, social distance, culture, and user engagement. The unit of analysis was the content and we collected information about the content producers and the content records. We controlled the views, comments, likes, calendar dates, and ages in the empirical models. The data was collected in 2011, with the records coming from South Korea, Japan, China, U.S., German, and France. A total of 4,980 elements were analyzed in the model. The empirical model estimated is the bivariate negative binomial distribution (NBD) model. Results - It turns out that there is a possibility that the matching effect can be diminished by variables that reflect the psychological involvement of user engagement. This study proposes academic and practical implications based on these research results. This research shows the positive effect of social distance between users and producers on the increased performance of the online content. We find the effect of social distance to be a stronger tendency in collectivism. The collectivists follow their sense of friendship and intimacy in their culture and, the social congruence effect can be found there as well. The effect, however, could erode in a social case where users are motivated by strong intrinsic and psychological factors. In addition, user engagement complicates the process of user decision making regarding the information. Conclusions - This study examines how the differential effects of social distance caused by culture could disappear through user commitment as a complicated user motivation. Some potential implications are as follows. First, a firm in the collectivism culture has to communicate based on the social distance. In fact, most online channels do not have a function that indicates the social distance as measured by favorites or subscribers. This function could help increase the performance of the content in online channels, but this increasing effect can only be found in a collectivist culture. Based on this, the firms have to communicate and announce to users the actual social distance between users and producers. Second, firms should develop a system that discovers the social distance and culture and shows these measures to users and producers, since the congruence effect between social distance and culture is found only for low user engagement. The firms can take the advantage of the congruence effect only for the development of the social distance and culture visualized system.

• Korean Journal of Remote Sensing
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• v.36 no.5_4
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• pp.1153-1166
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• 2020

The purpose of this study was to analyze the spatial correlation between the heat distribution map of the satellite imaging base and the factors that deepen the heat wave, and to explore the heat concentration area and the space where the risk of future heat wave may increase. The global Moran's I of population, land use, and buildings, which are the causes of heat concentration and heat wave deepening, is found to be high and concentrated in specific spaces. According to the analysis results of local Moran's I, heat concentration areas appeared mainly in large cities such as metropolitan and metropolitan areas, and forests were dominant in areas with relatively low temperatures. Areas with high population growth rates were distributed in the surrounding areas of Gyeonggi-do, Daejeon, and Busan, and the use of land and buildings were concentrated in the metropolitan area and large cities. Analysis by Bivarate Local Moran's I has shown that population growth is high in heat-intensive areas, and that artificial and urban building environments and land use take place. The results of this research can lead to the ranking of heat concentration areas and explore areas with environments where heat concentration is concentrated nationwide and deepens it, so ultimately it is considered to contribute to the establishment of preemptive measures to deal with extreme heat.

• Journal of Distribution Science
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• v.9 no.1
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• pp.49-59
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• 2011

Although the South Korean organic food market is in the infancy compared to other industrialized countries, Korean consumers'interest in organic food and retail stores devoting space to organic products have been rapidly increasing. Despite the fact of organic food popularity, the term "organic" is interpreted differently by individuals. As opposed to the US, Japan and the EU where have operated an integrated organic food labelling system, Korea has adopted complex organic labelling systems regulated by several different government bodies. As a result, complicated food labelling standards make consumers confused when purchasing organic foods. Furthermore, in terms of country of origin (COO), it is argued by a lot of researchers that COO effects vary from product to product and from country to country; moreover, other informational cues such as brand and price can influence COO effects. In modern society, COO labelling has been complicated, due to the sourcing, manufacturing and market locations of merchandise spread over the world. Accordingly, the evaluation of COO effects has become complex. In order to examine these issues, a quantitative research was selected to classify the commonfeatures of organic food consumers and construct statistics such as the extent to which people are aware of organic food and COO labellingvia a questionnaire which took place in two cities in Korea with a cluster sample of 161 organic food purchasers. As for the data analysis, one-way analysis of variance (ANOVA), T-tests, bivariate crosstatulations with Cramer's V were conducted,depending on the characteristics of variables and the assumptions the research data need to fit. It has been concluded that in general, Korean organic consumers comprehend the term "organic"in a closer way to the general concept rather than technical term, thus people do not appreciate environmentally labels which include organic food labels, although marital status influence the degree of label awareness, regardless of gender, age, education level and so on. Regarding COO effects on organic food, home organic products were Korean consumers'first choice over those from industrialized countries and developing nations. Specifically, in processed organic product category, domestically cultivated and processed organic products were absolutely preferred to leading national brands produced with imported ingredients and international brands. However, due to a lack of checks of ingredients' COO, consumers tend to purchase a leading national organic food brand, believing that it is a pure organic food sourced domestically. As a consequence, this research has suggested some important managerial implications and future research directions. In order to prevent consumer confusion when buying organic foods, it should be noted that consumers do not comprehend the organic food certifications, due to complicated labelling systems for organic produce and processed organic foods. Therefore, government bodies related to organic food distribution have to know consumers' perception of organic food labels and the significance of customer-oriented labels and reestablish labelling standards. Similarly, public advertising should be followed to raise public awareness of the labelling to enable customers to have the correct information. In addition, not only international marketers but also domestic marketers need to understand COO images and also the influence COO of ingredients has on the image of an organic product.

• Journal of the Korea Fashion and Costume Design Association
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• v.15 no.3
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• pp.119-135
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• 2013

The purpose of this study was to investigate the relationship between consumption values of preschooler clothing and purchasing satisfaction, company brand loyalty and involvement of preschooler clothing with the mothers of preschoolers. An online survey was adapted as methodology of this study. The collected 323 questionnaires were collected and statistically analyzed. The nine consumption value of preschooler clothing(vicarious satisfaction value, social value, functional value, convenient value, economic value, coordination value, aesthetic value, distinctive value, and fashionable value) resulted from the analysis of survey. Purchasing satisfaction, company brand loyalty, involvement of preschooler clothing was Uni-dimensional. Statistical analysis was performed with frequency analysis, descriptive statistics, exploratory factor analysis, multi-group analysis, confirmatory factor analysis, bivariate correlation analysis, distribution, structural equation, cluster analysis, independent sample t-test, one-way analysis of variance. The results of this study are as follows. In the consumption value of preschooler clothing influencing on the purchasing satisfaction was evaluated depending on the involvement of preschooler clothing group (high-involvement group, low-involvement group). In the low-involvement group, the most significant consumption value of preschooler clothing are economic value, convenient value, social value in order of importance; though in the high-involvement group, aesthetic value, social value, economic value in order of importance. Also the brand royalty was more affected by the purchasing satisfaction in the high-involvement group than in the low-involvement group. In conclusion, the relations of consumption value of preschooler clothing with purchasing satisfaction, company brand loyalty, involvement of preschooler clothing was established in study. The significances of this study is to provide the market segmentation strategy depending on the characteristics of preschooler clothing consumers and establish the information and direction to increase the company brand royalty and purchasing satisfaction.

• Journal of radiological science and technology
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• v.31 no.1
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• pp.33-39
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• 2008

Abdominal obesity, especially, visceral obesity is thought to be a risk factor of type 2 diabetes and cardiovascular disease such as hypertension, hyperlipidemia, coronary artery disease. Based on previous studies visceral fat accumulation is highly related to these diseases compared to subcutaneous fat accumulation. The purpose of this study was to see the relation between abdominal obesity and lipid profiles in adult women. The included subjects were 25 adult women(BMI > $23\;kg/m^2$), who visited the obesity clinic in a general hospital from April 2006 to September 2007. Blood pressure, fasting glucose and lipid profiles were measured. The abdominal fat distribution had been assessed by CT scan at the level of L4-L5. From bivariate analyses, the visceral fat accumulation showed negative correlations with TC and TC/HDL. The BMI, total abdominal fat and Visceral fat/Subcutaneous fat ratio showed significant correlations with visceral fat accumulation. From linear regression analyses of all the study subjects, TC, TG and HDL were found to be determinants of the visceral fat accumulation($R^2\;=\;0.474$).

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.3
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• pp.92-98
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• 2017

The rapid growth of engineering technology and the emergence of systemized and large-scale engineering systems have resulted in complexity and uncertainty throughout the lifecycle activities of engineering systems. This complex and large-scale engineering system consists of numerous components, but system failure can be caused by failure of any one of a number of components. There is a real difficulty in managing such a complex and large-scale system as a part. In order to efficiently manage the system and have high reliability, it is necessary to structure a system with a complex structure as a sub-system. Also, in the case of a system in which cause of failures exist at the same time, it is required to identify the correlation of the components lifetime and utilize it for the design policy or maintenance activities of the system. Competitive risk theory has been used as a theory based on this concept. In this study, we apply the competitive risk theory to the models with combined structure of series and parallel which is the basic structure of most complex engineering systems. We construct a competing risks model and propose a mathematical model of net lifetime and crude lifetime for each cause of failure, assuming that the components consisting a parallel system are mutually dependent. In addition, based on the constructed model, the correlation of cause of failure is mathematically analyzed and the hazard function is derived by dividing into net lifetime and crude lifetime.

• The Journal of the Acoustical Society of Korea
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• v.20 no.2
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• pp.3-9
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• 2001

In this paper, a random number generator for simulation of speech-waveform coders was designed. A random number generator having a desired probability density function and a desired power spectral density is discussed and experimental results are presented. The technique is based on Sondhi algorithm which consists of a linear filter and a memoryless nonlinearity. Several methods of obtaining memoryless nonlinearities for some typical continuous distributions are discussed. Sondhi algorithm is analyzed in the time domain using the diagonal expansion of the bivariate Gaussian probability density function. It is shown that the Sondhi algorithm gives satisfactory results when the memoryless nonlinearity is given in an antisymmetric form as in uniform, Cauchy, binary and gamma distribution. It is shown that the Sondhi algorithm does not perform well when the corresponding memoryless nonlinearity cannot be obtained analytically as in Student-t and F distributions, and when the memoryless nonlinearity can not be expressed in an antisymmetric form as in chi-squared and lognormal distributions.

• Journal of Fashion Business
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• v.15 no.6
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• pp.1-22
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• 2011

This paper is a study on the information required for developing Korean clothing products intended for Chinese students in Korea and for opening markets of Korean clothing and brands in China. It analyses the buying behaviors, purchasing ability, the favourite apparel type for clothing, and satisfaction with Korean clothing and brands of Chinese students in Korea, with which it seeks a program for South Korea branding to enter into the Chinese clothing market. Three hundred fifty seven students of Hannam University and PaiChai University Chung nam National University in Daejeon-city took part in this study. This paper adopts Descriptive Analysis, Crossing Analysis, Bivariate Correlations, and One-way ANOVA in SPSS 17.0 with Post Hoc Multiple Comparisons to know about the impact of demographic variables of Chinese students in Korea on buying information sources, the criteria for store selection, buying capacity, praise degree on various properties of Korean clothes products and their satisfaction with Korean clothes products. The first proposal of expanding China market for Korean merchants is to achieve maximum sales based on sales promotion strategies, such as the credit card corporations, the store display and sales person service development, SPA, design size development, and to upgrade consumption values. The second proposal is Korean clothes corporations should open the Internet shopping corresponding to the physical stores, the most frequently used information source of Chinese students is the network, from the age distribution of Internet users in 2008 in China, population above 10 and below 30 accounts for 66.7% of all users, In recommending clothes made in Korea to Chinese young people, on-line advertising will get better effects than other strategies, specially during advertisement, they should take good use of Korean television shows and variety shows or help Chinese poor areas to do the social contribution hereby to improve the public image of Korean clothes corporations, which can bring good sale promotion effects as well.

• The Korean Journal of Applied Statistics
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• v.29 no.4
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• pp.689-697
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• 2016

The most useful method for financial market risk management may be Value at Risk (VaR) which estimates the maximum loss amount statistically. The VaR is used as a risk measure for one industry. Many real cases estimate VaRs for many industries or nationwide industries; consequently, it is necessary to estimate the VaR for multivariate distributions when a specific portfolio is established. In this paper, the multivariate quantile vector is proposed to estimate VaR for multivariate distribution, and the Vector at Risk for multivariate space is defined based on the quantile vector. When a weight vector for a specific portfolio is given, one point among Vector at Risk could be found as the best VaR which is called as an alternative VaR. The alternative VaR proposed in this work is compared with the VaR of Morgan with bivariate and trivariate examples; in addition, some properties of the alternative VaR are also explored.