• Title/Summary/Keyword: Invariance test

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Bootstrap inference for covariance matrices of two independent populations (두 독립 모집단의 공분산 행렬에 대한 붓스트랩 추론)

  • 김기영;전명식
    • The Korean Journal of Applied Statistics
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    • v.4 no.1
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    • pp.1-11
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    • 1991
  • It is of great interest to consider the homogeniety of covariance matrices in MANOVA of discriminant analysis. If we lock at the problem of testing hypothesis, H : $\Sigma_1 = \Sigma_2$ from an invariance point of view where $\Sigma_i$ are the covariance matrix of two independent p-variate distribution, the testing problem is invariant under the group of nonsingular transformations and the hypothesis becomes H : $\delta_1 = \delta_2 = \cdots = \delta_p = 1$ where $\delta = (\delta_1, \delta_2, \cdots, \delta_p)$ is a vector of latent roots of $\Sigma$. Bias-corrected estimators of eigenvalues and sampling distribution of the test statistics proposed are obtained. Pooled-bootstrap method also considered for Bartlett's modified likelihood ratio statistics.

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The Probabilistic Production Simulation with Energy Limited Units Using the Mixture of Cumulants Approximation (에너지 제약을 갖는 발전기를 고려한 경우의 Mixture of Cumulants Approximation법에 의한 발전시뮬레이션에 관한 연구)

  • 송길영;김용하
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.40 no.12
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    • pp.1195-1202
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    • 1991
  • This paper describes a newly developed method of production simulation by using the Mixture of Cumulant Approximation (MOCA). In this method, the load is modelled as random variable (r.v.) which can be interpreted in terms of partitioning the load into various categories. We can consider the load shape of multi-modal characteristics. The number of load category and demarcation points of each load category are calculated automatically by using interpolation and least square method. Each generating unit of a supply system is modelled as r.v. of unit outage capacity according to the number of unit outage subset. Since the computation burden of each subset's moments increases exponentially as units are convolved to the system, we further derive the specific recursive formulae. In simulating the energy limited units, hydro unit simulation is performed using Energy Invariance Property and the simulation of pumped storage unit is modelled as compulsory and economic operations. The proposed MOCA method is applide to the test systems and the results are compared with those of cumulant and Booth Baleriaux method. It is verified that the MOCA method is considerably reliable and stable both pathological and well behaved system.

A study on the factors of convergent caring competency for promotion of caregivers' wellness of disabled children (장애자녀 돌봄제공자의 웰니스 증진을 위한 융복합 돌봄역량 요인 연구)

  • Lee, Yu-Ri;Kim, Nam-Jung
    • Journal of Digital Convergence
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    • v.14 no.2
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    • pp.479-487
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    • 2016
  • This study aimed to investigate the difference of the disabilities type of caring competency, caring appraisal(caring burden, caring satisfaction), self-help group support for parents who have children with disabilities. The data were collected by a self-reported questionnaire from 301 parents who have disabled children(180 mental disabilities & 121 physical disabilities). Given the three types of invariance satisfied, latent means analysis(LMA) is performed to test mean differences on the four factors across the two groups. According to LMA where the parents who have children with physical disabilities are used as the reference group, the parents who have children with mental disabilities showed higher latent mean values on the self-help group support and caring burden. However, the parents who have children with physical disabilities showed higher latent mean values on the caring satisfaction and caring competency.

A Study on Corporate Cultural-Art Supporting and Consumer Response Based on Creating Shared Value (공유가치 창출(CSV)을 통한 기업의 문화예술 지원과 수용자들의 반응에 대한 연구)

  • Kwon, Eun Jung;Ahn, Won Hyun;Kim, Cheeyong
    • Journal of Korea Multimedia Society
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    • v.16 no.3
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    • pp.388-398
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    • 2013
  • The purpose of this study is to examine that the effects of social philanthropy initiatives the firm's image of corporate social responsibility. The present study analyzed the structural relationship between three motivations of social philanthropy and evaluation of firm, using structural equation modeling as the method of analysis of the data which were collected from surveying 310 random individuals at galleries and performance halls across the nation. The current study found that the focus on customer value positively influenced the firm image, while motivation for enterprise value had a negative effects on the firm image. This study conducted the test of the structural model invariance across the groups. This study also found that the correlation of motivation for customer to the firm image was much stronger in CSV group than its counterpart. In contrast, the correlation of focus on firm enterprise value to the firm image was much stronger in CSR group than CSV.

Marketing strategy effects on brand interest and consumer behavior to establish a consumer relationship in fashion brand stores - Comparing of Korean and Chinese active seniors - (패션 브랜드 매장에서의 관계 형성을 위한 마케팅 전략이 브랜드 관심과 소비자 행동에 미치는 영향 - 한·중 액티브 시니어 소비자 비교를 중심으로 -)

  • Lee, Sang In;Yu, Jihun
    • The Research Journal of the Costume Culture
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    • v.29 no.5
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    • pp.634-650
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    • 2021
  • This study was conducted to investigate the effect of relationship and service marketing on the brand interest and behaviors among Korean and Chinese active senior consumers and whether this effect differed between the two groups. A survey was conducted by having participants complete questionnaires administered by a research firm. For empirical analysis, frequency, EFA, CFA, SEM, the metric invariance test, and multiple-group comparison analysis were performed. The analysis results revealed that relationship marketing positively affected both brand interest and consumer behavior. Although service marketing positively affected brand interest, it did not have a significant effect on consumer behavior. In other words, brand interest positively affected consumer behavior through relationship and service marketing. Multiple-group comparison analysis demonstrated that no difference existed between Korean and Chinese active consumers in terms of how relationship marketing affected their brand interest, but a difference existed in how it affected their behavior. Service marketing had a greater influence on Chinese active senior consumers' brand interest than on Korean active senior consumers. However no difference existed between the two groups with respect to how service marketing affected their behaviors. Finally, brand interest had a positive effect only on Korean active senior consumers' behavior through relationship and service marketing, but not on Chinese active senior consumers. In conclusion, relationship and service marketing should be used to enhance the brand interest among Korean active senior consumers, and business activities should be planned by building relationships with Chinese active senior consumers to affect their behavior.

Reexamination of Coach-Athlete Relationship Maintenance Scale in Pro Baseball (프로야구 코치-선수관계 유지 척도 재검증)

  • Huh, Jin-Young;Choi, Hun-Hyuk
    • 한국체육학회지인문사회과학편
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    • v.55 no.1
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    • pp.221-233
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    • 2016
  • The purpose of this study was to prove a development and initial validation of the korean version of coach-athlete relationship maintenance scale that originated from the work of Rhind & Jowett(2012) in pro baseball. The items were then administered to 132 Participants(29 coaches and 103 athletes) completed the questionnaires of the coach-athlete relationship maintenance in First preliminary investigation. Maximum likelihood estimate was used to identify the latent underlying structure. In order to verify the validity of Korean version of coach-athlete relationship maintenance was administered to an independent sample of 273 coaches and athletes. Pro baseball coach-athlete relationship maintenance is consisted of six factors(25 items) with conflict management, motivational, preventative, openness/assurance, support, and social network. SPSS18.0 and AMOS16.0 were used to analyze the exploratory factor analysis, confirmatory factory analysis and internal consistency, test-retest with bootstrapping using of the data in this study. The results of the pro baseball coach-athlete relationship maintenance scale had six factors with 25 items, and each six factor was positively correlated. Overall, this study verified pro baseball coach-athlete relationship maintenance questionnaire. Thus, suggest that path of comparing the differences between the first division and farm team by using the test of the structural model invariance across the groups.

A Study on the Effect of Donors' Utility on Their Intention for Donation Continuity Focusing on Private Contribution to Social Welfare Organizations (사회복지기관 개인기부자들의 기부효용감이 기부지속의도에 미치는 영향 -기관신뢰감과 자기수용감의 매개효과와 경제수준의 조절효과를 중심으로-)

  • Lee, Wonjune
    • Korean Journal of Social Welfare
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    • v.66 no.1
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    • pp.333-361
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    • 2014
  • By viewing donors for social welfare organization as both givers and beneficiaries, this study aims to address the correlations between the continuity of donors' contributions and enhanced sense of satisfaction as a consequence of participating in donation activities. The predominant concern of this study centers on: (1) the direct effects of individuals' emotional utility, demonstrable utility, trust toward donee organization, self acceptance on the continuation of their donation; (2) the direct effects of individuals' emotional utility, demonstrable utility, trust toward donee organizations on individuals' self-acceptance; (3) the direct effects of individuals' emotional utility, demonstrable utility on their trust toward a donee organization; (4) the indirect effects of individuals' self acceptance on two paths i.e. emotional utility${\rightarrow}$trust${\rightarrow}$self acceptance, and demonstrable utility${\rightarrow}$trust${\rightarrow}$self acceptance; (5) the indirect effects of individuals' individuals' trust toward donee organization on self acceptance on four paths i.e. emotional utility${\rightarrow}$trust${\rightarrow}$continuity of donation; demonstrable utility${\rightarrow}$trust${\rightarrow}$continuity of donation; emotional utility${\rightarrow}$trust${\rightarrow}$self-acceptance, and demonstrable utility${\rightarrow}$trust${\rightarrow}$self-acceptance; (6) the moderating effects of 'financial status' on the causal relationships in the prescribed structural equation model(SEM). In order to verify the moderating effect of 'financial status', multi-group analysis between each of the two groups were conducted. Research is based on a survey among 1116 donors who had made charitable, monetary contributions to social welfare organizations in Daegu and Kyungpook province. Data was collected from 29 organizations. In order to address the research questions, structural equation were employed. A variety of tests are conducted(metric invariance, critical ratio for difference, structural invariance, multi-group analysis, bias-corrected boot-strapping, latent mean analysis including Cohen's effect test).

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A Validation study of the Korean Version of Material Values Scale (한국판 물질주의척도의 타당화 연구)

  • Ji Hae You;Kyoung Ok Seol
    • Korean Journal of Culture and Social Issue
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    • v.24 no.3
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    • pp.385-410
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    • 2018
  • Materialistic values can be a important variable to understand Koreans' psychological well-being and mental health. This study aimed to validate the Korean version of the Material Values Scale (K-MVS)(Richins & Dawson, 1992). In study 1, we performed confirmatory factor analysis(CFA) to ascertain the three factor model of the original MVS using 417 Korean undergraduate student data(sample 1). The CFA confirmed the three-factor model of the MVS. Yet, three items that yielded low factor loadings in this study as well as in other MVS validation studies were excluded from the final model. In study 2, content, construct, and concurrent validity of the K-MVS were examined with 650 undergraduate student data(Sample 2). We also tested measurement invariance across two groups(i.e., college student group of Sample 2 and employee group of Sample 3). The result revealed that the three-factor model of the K-MVS hold true across the two groups. Lastly test-retest reliability was calculated with 408 female college student data(Sample 4) that filled out K-MVS twice within 6 months. These findings suggest that the K-MVS is a reliable and valid measure for assessing materialistic values in Korea.

The Effects of Job Satisfaction, Social Support and Hope on Life Quality of Mongolian Workers: Focusing on the Mediating Effects of Hope and the Moderating Effect of the Legal Status (재한 몽골 합법·불법 이주노동자들의 직업만족도, 사회적 지지, 희망이 삶의 질에 미치는 영향: 희망의 매개효과와 체류자격의 조절효과를 중심으로)

  • Sung Ja Shin;Mijid-Ochir Otgondulam
    • Korean Journal of Culture and Social Issue
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    • v.18 no.4
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    • pp.435-462
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    • 2012
  • The predominant concern of the study centers on: (1) the direct effects of the job satisfaction, social support and hope on the individual's quality of life; (2) the direct effect of hope alone on the individual's quality life; (3) the mediating effect of the hope between the job satisfaction/social support and life quality; (4) the moderating effect of the worker's legal status(legal labors Vs. illegal labors) on each causal relationship. Research is based on a survey conducted with 453 Mongolian immigrant workers(333 legal workers, 120 illegal workers) from 10 cities including Seoul. In order for respondents to address research questions, structural equation models are explored. A variety of tests are conducted(metric invariance test, critical ratio for difference test, multi-group analysis, bias-corrected boot-strapping, latent mean analysis including Cohen's effect test). The noticeable findings are as follow: First, both job satisfaction and social support have a positive influence respectively on the individual's hope and the individual's quality of life. Second, we found a partial mediating effect of hope between both job satisfaction/social support and the individual's life quality. Third, we failed to find a moderating effect of the workers' legal status on each causal relationship. Finally, there is no significant difference of the latent means of each latent variable -job satisfaction, social support, hope, and life quality - between the legal group and the illegal group, except the latent mean of workers' quality of life. A range of practical and political implications are discussed based on the study's findings.

Long-term Prognostic Value of Dipyridamole Stress Myocardial SPECT (디피리다몰 부하 심근관류 SPECT의 장기예후 예측능)

  • Lee, Dong-Soo;Cheon, Gi-Jeong;Jang, Myung-Jin;Kang, Won-Jun;Chung, June-Key;Lee, Myoung-Mook;Lee, Myung-Chul;Kang, Wee-Chang;Lee, Young-Jo
    • The Korean Journal of Nuclear Medicine
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    • v.34 no.1
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    • pp.39-54
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    • 2000
  • Purpose: Dipyridamole stress myocardial perfusion SPECT could predict prognosis, however, long-term follow-up showed change of hazard ratio in patients with suspected coronary artery disease. We investigated how long normal SPECT could predict the benign prognosis on the long-term follow-up. Materials and Methods: We followed up 1169 patients and divided these patients into groups in whom coronary angiography were performed and were not. Total cardiac event rate and hard event rate were predicted using clinical, angiographic and SPECT findings. Predictive values of normal and abnormal SPECT were examined using survival analysis with Mantel-Haenszel method, multivariate Cox proportional hazard model analysis and newly developed statistical method to test time-invariance of hazard rate and changing point of this rate. Results: Reversible perfusion decrease on myocardial perfusion SPECT predicted higher total cardiac event rate independently and further to angiographic findings. However, myocardial SPECT showed independent but not incremental prognostic values for hard event rate. Hazard ratio of normal perfusion SPECT was changed significantly (p<0.001) and the changing point of hazard rate was 4.4 years of follows up. However, the ratio of abnormal SPECT was not. Conclusion: Dipyridamole stress myocardial perfusion SPECT provided independent prognostic information in patients with known and suspected coronary artery disease. Normal perfusion SPECT predicted least event rate for 4.4 years.

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