• 응용통계연구
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• 제15권1호
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• pp.57-71
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• 2002

본 논문에서는 지수생존 모형의 형태들로써 단순 지수모형, 변환 점 지수모형과 유한 혼합 지수모형 등 세 가지 모형을 소개한다. 이러한 모형들 중에서, 최적의 모형을 찾기 위하여 Gelfand와 Ghosh(1998)의 방법을 이용한 모형 선택 방법을 제안한다. 이때, 계산상의 어려움을 피하기 위하여 자료 확장 기법(Tanner와 Wong, 1987)과 깁스 샘플러(Gelfand와 Smith, 1990)를 사용하였다. 제안된 베이지안 방법을 설명하기 위하여 모의 실험 자료와Stangl의 항 우울제 자료에 적용한다. 모형 선택 방법은 사전 분포와 모형 선택 기준의 가중치에 민감하지 않다는 것을 제한된 우리의 실험으로 알 수 있었다.

• International Journal of Human Ecology
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• 제16권2호
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• pp.63-77
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• 2015

The current study investigated how academic stress, academic burnout, and academic self-efficacy relate to each other; in addition, this study examined the mediating effects of academic self-efficacy on the relationship between academic stress and academic burnout of Chinese adolescents. A total of 412 students attending third-grade from two different middle schools (ninth-grade in the United States) located in Jiading District of Shanghai participated in the final analysis. By using structural equation modeling (SEM) and the maximum likelihood estimation procedures of AMOS 20.0, the latent variable measurement models were confirmed. The results and conclusions of this study are summarized as follows. A positive correlation between academic stress and academic burnout was soundly supported by this study. Meanwhile, both academic stress and academic burnout indicated negative correlations with academic self-efficacy. The modeling indicated that academic self-efficacy has a partial mediating process and a direct effect on the relationship between academic stress and academic burnout. Thus, academic stress and academic burnout were significantly weaker when academic self-efficacy was higher. In the field of education and curriculum, these results are applicable for restructuring or developing Chinese middle school curriculum utilizing useful methods for adolescents to develop their academic self-efficacy.

• 지역사회간호학회지
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• 제12권3호
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• pp.557-569
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• 2001

The purpose of the study was to test the Pender's New Health Promotion Model in order to explain and predict female workers' health promotion behavior at manufacturing plants by using latent variable structural equation model. The data were collected from 280 female workers at 8 electronic factories located at Seoul. Kyunggi. and Incheon using a structured questionnaire through interview and self-report. LISREL was used to test the model. The results are as follows: 8 out of 15 paths of the modified one from the hypothetical model of Health Promotion were statistically significant and the total variance was 40%. The relationship between the previous health behavior and the cognitive emotional factor, and the interpersonal factor. and the situational factor each. and the relationship between perceived health status and interpersonal factor, and health promotion behavior each among gamma paths were unidirectional. On the beta paths. the relationship between the interpersonal factor and the cognitive emotional factor was bi-directional: the relationships amongst the interpersonal factor and the commitment to action, and the health promotion behavior were unidirectional. But the commitment to action was not a significant mediating factor to the health promotion behavior. Pender's New Model is considered good to explain and predict the female workers' health promotion behavior. The interpersonal factor should be considered in occupational nursing practice. But the concepts of situation and commitment to action should be further validated and measured.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 추계 학술논문 발표대회
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• pp.66-67
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• 2013

Replacing a large amount of ground granulated blast furnace slag is limited because early age strength is low due to latent hydraulic property despite excellence of long-term strength. This study aimed to examine produceableness of high-activated ground granulated blast furnace slag using slag by-product from steel process. As experimental variable, the properties of strength development were analyzed by setting fineness and replacement ratio of slag by-product, curing conditions, and W/B. The results of study showed that high-activated ground granulated blast furnace slag using slag by-product as an activator improve the compressive strength of mortar. It is expected to be used as binder for secondary product of concrete considering curing and mixing conditions because high-activated ground granulated blast furnace slag can be hydrated by itself.

• Parasites, Hosts and Diseases
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• 제39권3호
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• pp.223-226
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• 2001

In South Korea, the north border area has been under vivax malaria epidemic since 1993. However, Jeollabuk-do, which is about 300 kms from the border, has not experienced the same epidemic. 1 investigated a total of 58 notified cases of malaria in Jeollabuk-do in the year 2000. All of the cases had an exposure history in the epidemic area. Among them were 49 ex-soldiers, 3 soldiers who served near the border area and 6 civilians who traveled there. The causal agent of all cases was Plasmodium vivax. Except the civilians, the soldiers and ex-soldiers were aged in their twenty's. In the present study, the incubation period was from 6 to 520 days with a median of 157 days, and the latent onset type (92%) was more prevalent than the early onset type. illness onset of most cases (86%) peaked during the summer season (June to September) despite of variable incubation periods. The time lag for diagnosis ranged from 2 to 42 days with a median of 11 days. Jeollabuk-do has not been an area of epidemic untill now, but incidences have been increasing annually since 1996. In Jeollabuk-do, early diagnosis and treatment can be a feasible disease control measure to prevent spreading from the epidemic area.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권5호
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• pp.2299-2318
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• 2019

Location-aware networks are of great importance for both civil lives and military applications. Methods based on line-of-sight (LOS) measurements suffer sever performance loss in harsh environments such as indoor scenarios, where sensors can receive both LOS and non-line-of-sight (NLOS) measurements. In this paper, we propose a data association (DA) process based on the expectation maximization (EM) algorithm, which enables us to exploit multipath components (MPCs). By setting the mapping relationship between the measurements and scatters as a latent variable, coefficients of the Gaussian mixture model are estimated. Moreover, considering the misalignment of sensor position, we propose a space-alternating generalized expectation maximization (SAGE)-based algorithms to jointly update the target localization and sensor position information. A two dimensional (2-D) circularly symmetric Gaussian distribution is employed to approximate the probability density function of the sensor's position uncertainty via the minimization of the Kullback-Leibler divergence (KLD), which enables us to calculate the expectation step with low computational complexity. Moreover, a distributed implementation is derived based on the average consensus method to improve the scalability of the proposed algorithm. Simulation results demonstrate that the proposed centralized and distributed algorithms can perform close to the Monte Carlo-based method with much lower communication overhead and computational complexity.

• KDI Journal of Economic Policy
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• 제40권4호
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• pp.1-22
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• 2018

We estimate three continuous-time stochastic volatility models following the approach by Aït-Sahalia and Kimmel (2007) to compare the Korean and US stock markets. To do this, the Heston, GARCH, and CEV models are applied to the KOSPI 200 and S&P 500 Index. For the latent volatility variable, we generate and use the integrated volatility proxy using the implied volatility of short-dated at-the-money option prices. We conduct MLE in order to estimate the parameters of the stochastic volatility models. To do this we need the transition probability density function (TPDF), but the true TPDF is not available for any of the models in this paper. Therefore, the TPDFs are approximated using the irreducible method introduced in Aït-Sahalia (2008). Among three stochastic volatility models, the Heston model and the CEV model are found to be best for the Korean and US stock markets, respectively. There exist relatively strong leverage effects in both countries. Despite the fact that the long-run mean level of the integrated volatility proxy (IV) was not statistically significant in either market, the speeds of the mean reversion parameters are statistically significant and meaningful in both markets. The IV is found to return to its long-run mean value more rapidly in Korea than in the US. All parameters related to the volatility function of the IV are statistically significant. Although the volatility of the IV is more elastic in the US stock market, the volatility itself is greater in Korea than in the US over the range of the observed IV.

• The Journal of Asian Finance, Economics and Business
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• 제8권5호
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• pp.897-911
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• 2021

This study aims to analyze the important role of business analytics capability, information quality, and innovation capability in influencing organization agility and organization performance during the Covid-19 pandemic. Data was collected from 76 companies from various sectors in Indonesia. Structural Equation Model-Partial Least Square (SEM-PLS) analysis was conducted to analyze the relationship between variables and test a series of hypotheses. Importance-Performance Matrix Analysis (IPMA), a useful analysis approach in PLS-SEM, is used, which extends the results of the estimated path coefficient (importance) by adding a dimension that considers the average values of the latent variable scores (performance). The IPMA approach examines not only the performance of an item but also the importance of that item. The results show that business analytics capability has a significant effect on information quality and innovation capability which then affects organization agility. Organizational performance is influenced by organizational agility. IPMA results show that organizational agility has the highest level of impact on organizational performance. This study will assist companies in planning business analytics, improving information quality, increasing innovation capability, and ultimately increasing agility and performance during the Covid-19 pandemic. This study will add to existing knowledge about previous literature, especially in the Covid-19 pandemic situation.

• The Journal of Asian Finance, Economics and Business
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• 제8권2호
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• pp.911-921
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• 2021

Indonesian oil palm plantation industry has chance to increase a sustainable competitive advantage. The creation of a sustainable competitive advantage is determined by the ability of the palm oil industry to utilize limited resources and capabilities. The purpose of this study was to analyze the determinants of the creation of sustainable competitive advantage (SCA) in the palm oil industry in Riau, Indonesia. The model framework uses organizational-level SCA dimensions. Four dimensions are used to measure SCA in the palm oil industry in Riau, namely value, scarce resource, inability to replicate, irreplaceable. Questionnaires were distributed to oil palm industry players in Riau with 81 respondents. The analysis technique uses Structural Equation Model with Partial Least Square (SEM-PLS). The results showed that the SCA in the palm oil industry in Riau was at a moderate level. Although the competitive advantage of being sustainable in the palm oil industry in Riau is in the medium category, test results on SCA dimensions found that each latent variable forms a significant SCA framework with a reflective constructive relationship model. The three dominant and recommended dimensions that shape the construction of SCA in the palm oil industry are value, scarce resource, and irreplaceable.

• The Journal of Asian Finance, Economics and Business
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• 제8권7호
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• pp.255-264
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• 2021

The purpose of this study is to analyze the role of customer value and customer trust as a mediator of flexibility influence on customer retention. The study applies SEM tools with WarpPLS analysis and translates customer value and customer trust as mediation. This study was organized into three parts: exploratory research, descriptive research, and explanatory research. The quantitative approach in this study uses a survey method by taking samples from the population. This is a latent variable that is measured using a research instrument in the form of a questionnaire. The survey was conducted by distributing questionnaires to respondents. This research was conducted at PT. Nusa Prima Logistics Terminal Teluk Lamong by taking primary data, in the form of assessments or perceptions from respondents, so a survey was conducted by submitting a questionnaire directly to 194 respondents. Quantitative data analysis was performed using Structural Equation Modeling (SEM) to answer the research hypothesis. Flexibility is very influential in increasing customer retention so to develop customer retention, it is necessary to increase flexibility, customer value, and customer trust. The novelty in this research lies in identifying the role and position of customer value and customer trust as mediation that affect customer retention.