• 제목/요약/키워드: Bivariate distribution

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2차원 벡터 공정능력지수 Cpmk의 추정량과 극한분포 이론에 관한 연구 (On the Plug-in Estimator and its Asymptotic Distribution Results for Vector-Valued Process Capability Index Cpmk)

  • 조중재;박병선
    • Communications for Statistical Applications and Methods
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    • 제18권3호
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    • pp.377-389
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    • 2011
  • 공정능력지수는 공정능력을 측정하고 분석하기 위하여 매우 중요한 역할을 하는 측도로, 품질수준과 밀접한 관계가 있을 뿐만 아니라 보다 높은 품질수준은 고객들에게 더 큰 만족을 가져다 준다. 제3세대 공정 능력지수 $C_{pmk}$는 gms히 6시그마 산업현장에서 공정능력을 평가하기 위하여 유용하게 사용되는 두 가지 지수 $C_p$$C_{pk}$보다 이론적으로 강력한 지수이다. 실제로 제조현장에서 두 가지 이상의 서로 연관이 있는 품질특성치들과 제품에 대한 규격한계들을 사용하여 보다 정확한 공정능력 분석이 필요할 것이다. 이러한 경우에 단순히 하나의 일변량 공정능력지수를 통하여 공정능력분석을 하기 보다는 벡터 공정능력지수나 다변량공정능력지수를 통하여 분석을 수행하는 것이 바람직할 것이다. 본 논문에서는 3세대 공정능력지수 $C_{pmk}$를 고려하여 2차원 벡터 공정능력지수 $C_{pmk}$ = ($C_{pmkx}$, $C_{pmky}$)$^t$에 대하여 연구하였다. 우선, $C_{pmk}$에 대한 플러그-인(plug-in) 추정량 $\hat{C}_{pmk}$과 관련하여 핵심내용인 극한 확률분포를 유도하였다. 나아가 이러한 결과를 기초로 이변량 정규분포하에서 공분산 행렬 $V_{pmk}$을 구체적으로 계산하였다. 또한 이 행렬의 추정을 통하여 벡터 공정능력지수 $C_{pmk}$에 대한 근사적인 공동 신뢰영역을 제시함으로써, 본 논문에서의 극한분포 연구결과가 벡터 공정능력지수 $C_{pmk}$에 대한 통계적 추론에 유용하게 활용될 수 있음을 보여주었다.

온라인 유통 채널에서 컨텐츠의 성과는 사회적 거리에 의해 항상 증가하는가? YouTube의 문화별컨텐츠를 중심으로 (Does Social Distance Always Increase Content Performance in Online Distribution Channels?)

  • 손정민;강성호
    • 유통과학연구
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    • 제13권8호
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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.

MODIS 기반의 열 분포도를 활용한 열 집중지역과 폭염 심화요인 간의 공간관계 특성 연구 (Study on the Characteristics of Spatial Relationship between Heat Concentration and Heat-deepening Factors Using MODIS Based Heat Distribution Map)

  • 김보은;이미희;이달근;김진영
    • 대한원격탐사학회지
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    • 제36권5_4호
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    • pp.1153-1166
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    • 2020
  • 본 연구는 위성영상 기반의 열 분포도 및 폭염을 심화시키는 요인 간의 공간적 상관성을 분석하여 열 집중지역과 향후 폭염 위험이 증가할 수 있는 공간의 탐색을 목적으로 수행되었다. 열 집중지역과 폭염 심화요인의 인구, 토지이용, 건축물 각각의 전역적 Moran's I는 높게 나타나 특정 공간에 집중하는 것으로 나타났다. 국지적 Moran's I 분석 결과로, 열 집중지역은 수도권 및 광역시 등 대도시에서 주로 나타났고 상대적으로 온도가 낮은 지역은 산림지역이 우세한 강원도 및 경상북도, 소백산맥 지역에서 집중적으로 나타났다. 인구증가율이 높은 지역은 서울 주변의 경기도, 대전, 부산 인근지역에서 군집 분포하였으며 토지이용과 건축물은 수도권과 대도시에 집중하는 유사한 공간 패턴을 보였다. Bivariate Local Moran's I 분석결과는 열이 집중된 지역에서 인구증가율이 높고, 인공적·도시적 건축환경 및 토지이용이 이루어지는 것으로 나타났다. 본 연구결과는 열 집중지역의 순위를 도출할 수 있으며 전국적으로 열이 집중되고 이를 심화시킬 수 있는 환경을 가진 지역을 탐색할 수 있으므로 궁극적으로 선제적 폭염 대응대책 수립에 기여할 수 있을 것이다.

Korean consumers' attitudes towards organic labels and country-of-origin of organic foods

  • Lee, Hye-Kyoung;Cho, Young-Sang
    • 유통과학연구
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    • 제9권1호
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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.

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어머니의 유아복 관여도 조절효과에 따른 유아복 소비가치, 구매만족, 브랜드 충성도의 관계연구 (The Relationship between Consumption Value of Preschooler Clothing, Purchase Satisfaction and Brand Loyalty according to the Moderating Effects of Mother's Preschooler Clothing Involvement)

  • 이주연;이영주
    • 한국의상디자인학회지
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    • 제15권3호
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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.

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전산화 단층촬영을 이용한 성인여성의 복부비만과 지질대사지표와의 연관성 (The Relationship of Abdominal Obesity and Lipid Profiles by Computed Tomography in Adult Women)

  • 김미영
    • 대한방사선기술학회지:방사선기술과학
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    • 제31권1호
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    • pp.33-39
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    • 2008
  • 복부비만은 2형 당뇨병과 고지혈증, 고혈압, 관상동맥질환 등의 심혈관계 질환의 주요 위험인자이며 특히 내장형 복부 비만인 경우 위험도가 더 크다고 알려져 있다. 이 연구에서는 2006년 4월부터 2007년 9월까지 일개 대학병원 비만 클리닉을 방문한 BMI 23 이상의 성인 여성 25명을 대상으로 하여 복부지방 CT를 실시하여 지질대사지표와의 상관성 및 내장지방 분포에 영향을 주는 요인을 분석하였다. 8시간 공복 후 채취한 정맥혈액을 이용하여 Glucose, TC, TG, HDL의 농도를 분석하였고, 안정시의 이완기 혈압과 수축기 혈압을 측정하였다. 연구결과 내장지방량은 TC와 TC/HDL과 음의 상관관계를 보였다. 통계적으로는 BMI, TAF, VSR이 통계적으로 유의한 차이가 있는 것으로 나타났다(p < .001). 내장지방량을 가장 잘 반영하는 지질대사지표는 TC와 TG, HDL인 것으로 나타났으며, 이 회기분석모델은 47%의 설명도를 가지고 있는 것으로 나타났다.

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종속적 관계를 갖는 혼합구조에 대한 경쟁적 위험모형의 구축 (Constructing a Competing Risks Model for the Combined Structure with Dependent Relations)

  • 박성환;박지현;배기호;안선응
    • 산업경영시스템학회지
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    • 제40권3호
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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.

음성엔코더 시뮬레이션에 사용되는 난수발생기 설계 (Design of Random Number Generator for Simulation of Speech-Waveform Coders)

  • 박중후
    • 한국음향학회지
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    • 제20권2호
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    • pp.3-9
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    • 2001
  • 본 논문에서는 음성엔코더 (speech-waveform coder) 시뮬레이션에 사용할 수 있는 난수발생기를 설계하였다. 설계된 난수발생기는 규정된 확률밀도함수와 규정된 스펙트럼을 동시에 만족해야 하는 환경에서 필요로 하는 것이다. 선형필터와 메모리가 없는 비선형 회로로 구성되는 Sondhi 알고리즘 [1]을 기반으로 하여 난수발생기를 구현하였고, 균일 분포, 이진 분포, 감마 분포와 같은 연속적인 확률분포함수들을 얻기 위해 필요한 선형필터와 비선형 회로를 구현하는 방법을 연구하였다. 또한 분석적인 방법을 통하여 구현해야 하는 비선형 회로가 비대칭 형태로 표현되지 않는 경우 (카이-제곱 분포, lognormal 분포)와 수학식으로 표현할 수 없는 경우 (Student-t 분포, F 분포)에는 Sondhi 알고리즘이 동작하지 않음을 보였다.

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Suggestion on Chinese Clothing Market Launching : Focused on Foreign Students's Clothing Buying Behavior in Korea

  • Koo, In-Sook;Liu, Dashuang
    • 패션비즈니스
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    • 제15권6호
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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.

Vector at Risk와 대안적인 VaR (Vector at Risk and alternative Value at Risk)

  • 홍종선;한수정;이기쁨
    • 응용통계연구
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    • 제29권4호
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    • pp.689-697
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    • 2016
  • 금융시장 위험관리 수단으로 많이 사용하는 기법 중의 하나는 Morgan이 제안한 최대손실금액을 추정하는 VaR (Value at Risk)이다. VaR은 한 산업의 금융위험 측정도구로 사용되어지지만 실제 생활에서는 여러 회사 또는 국내 전체의 산업의 VaR를 추정하는 경우가 많다. 따라서 투자할 여러 산업에 대하여 특정한 포트폴리오가 설정된 경우에 다변량분포에 대한 VaR를 추정하는 문제가 필요하다. 본 연구에서는 다변량분포에 대한 VaR를 추정하기 위하여, 다차원 분위 벡터를 제안하고, 이를 바탕으로 다차원 공간에서의 Vector at Risk를 정의한다. 다변량분포에 대하여 특정한 포트폴리오가 설정된 경우에, Vector at Risk 중에서의 한 점을 가장 적절한 VaR로 설정하는 방법을 제안한다. 이를 대안적인 VaR이라고 정의하고, 다변량 분포에 대한 이 방법에 대하여 토론한다. 2변량과 3변량의 예제를 통해 본 연구의 대안적인 VaR과 Morgan의 VaR를 각각 구하고, 비교 설명하면서 대안적인 VaR의 특징을 탐색한다.