• 한국도로학회논문집
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• 제20권2호
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• pp.119-126
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• 2018

PURPOSES : The purpose of this study is to develop a crash prediction model at signalized intersections, which can capture the randomness and uncertainty of traffic accident forecasting in order to provide more precise results. METHODS : The authors propose a random parameter (RP) approach to overcome the limitation of the Count model that cannot consider the heterogeneity of the assigned locations or road sections. For the model's development, 55 intersections located in the Daejeon metropolitan area were selected as the scope of the study, and panel data such as the number of crashes, traffic volume, and intersection geometry at each intersection were collected for the analysis. RESULTS : Based on the results of the RP negative binomial crash prediction model developed in this study, it was found that the independent variables such as the log form of average annual traffic volume, presence or absence of left-turn lanes on major roads, presence or absence of right-turn lanes on minor roads, and the number of crosswalks were statistically significant random parameters, and this showed that the variables have a heterogeneous influence on individual intersections. CONCLUSIONS : It was found that the RP model had a better fit to the data than the fixed parameters (FP) model since the RP model reflects the heterogeneity of the individual observations and captures the inconsistent and biased effects.

• 노동경제논집
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• 제36권1호
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• pp.45-62
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• 2013

본 연구에서는 소득이질성과 개인의 공공재 공급행위(여기서는 자원봉사활동) 간의 상관관계를 우리나라의 통계청 자료를 사용해 분석하였다. 관련문헌에 대한 차별화된 공헌으로, 첫째, 소득이질성의 영향을 개인의 소득계층별 위치에 따른 영향과 분리하여 이론화하여 실중분석하였고, 둘째, 관련실증문헌의 주요 쟁점 중 하나인 소득이질성을 정의하는 오목함수 지역단위의 설정 문제에 대한 대응방안을 제시하였고, 셋째, 봉살활동에 소극적인 경역단위 설명변수의 내생성 문제를 극복한 결과를 제시하였고, 넷째, 자원봉사활동 단순 참여 여부만을 고려하는 선행연구와 달리 자원봉사시간을 가중치로 사용해 기존 연구의 실증분석 결과의 강건도를 점검하였다. 실증분석 결과를 종합할 때 소득이질성이 커지면 다수의 선행연구와 유사하게 자원봉사행위의 저하 가능성이 있음을 확인할 수 있었다.

• Asian-Australasian Journal of Animal Sciences
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• 제12권6호
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• pp.846-849
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• 1999

Angus postweaning daily gain (PWDG) were analyzed to investigate heterogeneous variance by sex. A set of data (16,239 records) was divided into six sub-data sets according to level of environment. REML estimation was conducted by a multitrait model, where PWDG in each sex was treated as a separate trait. Estimates showed diversity among environmental levels, where the heritability for heifers was high in good environment but low in poor environment. The bull's estimates varied among environmental levels. The largest heterogeneity of phenotypic variance between sexes was estimated in a data set of the poor environment level. The genetic correlations between the heifer's PWDG and the bull's PWDG were high in the good environment and low in the poor environment (-0.17). The results suggest existence of genotype by sex interaction in the poor environment.

• Journal of the Korean Statistical Society
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• 제36권1호
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• pp.129-148
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• 2007

Frailty estimates from the proportional hazards frailty model often lead us to conjecture the heterogeneity in frailty such that the variance of the frailty varies over different covariate groups (e.g. male group versus female group). For such systematic heterogeneity in frailty, we consider a regression model for the variance components in the proportional hazards frailty model, denoted by the MLFM. However, in many cases, the observed data do not show any statistically significant preference between the homogeneous frailty model and the heterogeneous frailty model. In this paper, we propose a Bayesian model averaging procedure with the reversible jump Markov chain Monte Carlo which selects the appropriate model automatically. The resulting regression coefficient estimate ignores the model uncertainty from the frailty distribution in view of Bayesian model averaging (Hoeting et al., 1999). Finally, the proposed model and the estimation procedure are illustrated through the analysis of the kidney infection data in McGilchrist and Aisbett (1991) and a simulation study is implemented.

• Asian Journal of Innovation and Policy
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• 제10권3호
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• pp.294-315
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• 2021

Since the division of South and North Korea in 1945, there has been little exchange in science and technology, despite some interchange in a few fields including the chemistry area. Accordingly, the difference in scientific and technological terminology between the two Koreas has become intensified. This is because North Korea carried out a campaign to purify the Korean language and blocked the inflow of foreign words. They also tried to convert into their own North Korean terms in many fields. This circumstance in North Korea aggravated the heterogeneity of inter-Korean scientific and technological terms. In particular, the heterogeneity of chemical terminology has worsened due to the different characteristics of the technology donor countries such as the United States and Japan in South Korea, and China and the Soviet Union in North Korea between the two Koreas and the different way of technological development. The purpose of this study is to collect chemical terminology data used in two Koreas and analyze similarities and differences. Through comparative analysis of inter-Korean terminology in the chemical field, it can be possible to recognize how the chemical terms between the two Koreas have changed since the division and the degree of heterogeneity based on different technical systems and language policies. The outcome of this study would present basic data on the unification of chemical terminology in preparation for before and after unification, and contribute to communication and academic exchange between researchers in the inter-Korean scientific and technological fields, including chemistry.

• 한국노년학
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• 제40권1호
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• pp.73-89
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• 2020

본 연구는 정순둘 등(2015)이 개발한 연령통합척도를 Riley 등(1994)이 개념구성한 연령유연성과 연령다양성을 하위요인으로 한 단축형 연령통합척도로 척도의 타당성을 검증하여 척도의 실용성을 확보하고, 인구사회학적 특징에 따른 연령통합인식을 파악하는 것을 목적으로 하였다. 이를 위해 한국연구재단에서 지원한 사회과학역량강화지원사업(SSK)의 지원을 받아 수행된 '연령통합 및 세대통합 조사'자료의 총 1433명을 대상으로 분석하였다. 분석방법은 탐색적 요인분석, 확인적 요인분석, 다집단 요인분석, 평균비교 등의 방법을 활용하였다. 분석결과는 다음과 같다. 첫째, 척도는 총 28문항에서 13문항으로 수정되었으며, 연령다양성 8문항, 연령유연성 5문항으로 구성되었다. 둘째, 청년, 중년, 노년 집단으로 분류하여 다집단 요인분석에서 연령집단 간에 유의한 차이를 보이지 않는 것으로 나타나 전 연령에서 사용가능성이 확보되었다. 셋째, 연령집단 간 인구사회학적 특성에 따른 연령통합인식 차이에서 청년집단은 거주지역에서만 연령통합인식, 연령유연성, 연령다양성 차이를 보이는 것으로 나타났으며, 중년집단에서는 거주지역과 계층인식에서 연령통합인식, 연령 유연성, 연령다양성 차이를 보였다. 노년집단은 연령통합인식에서는 거주지역, 교육수준, 계층인식이 유의미하였으며, 연령유연성에서는 거주지역과 계층인식, 연령다양성에서는 거주지역과 교육수준에서 유의미한 차이를 보였다. 이러한 본 연구의 결과를 기반으로 향후 연령통합인식 향상을 위한 연구를 위한 방향과 정책 및 실천을 위한 함의를 제언하였다.

• 한국정보통신학회논문지
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• 제10권12호
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• pp.2212-2220
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• 2006

최근 기업들은 레거시 시스템들간의 데이터 상호 운용하기 위해 기업들은 이미 보유하고 있는 레거시 업무와 EAI 시스템을 도입하고 있다. 협업적인 거래 환경에서의 EAI 시스템은 유기적으로 통합하고 공유함으로서 효율적인 검색을 기대할 수 있다. 그러나 기존 레거시 시스템은 특정 목적에 따라 설계단계부터 상호 운용성을 고려하지 않고 독자적으로 관리되므로 EAI는 표준기술 적용이 어려우므로 별도의 전용 EAI 솔루션을 도입해야 한다. 이러한 문제를 해결하기 위해 데이터 통합을 이용하여 메타데이터 레지스트리를 이용한다. 그러나 메타데이터의 다양한 타입과 의미론적 명세, 데이터 이질성 문제, 이기종간의 시스템 이질성에 대한 문제도 야기된다. 따라서 본 논문에서는 웹 환경에서 데이터 상호운용을 위한 XMDR(eXtended Meta-Data Registry) 기반의 검색 시스템을 제안한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제18권5호
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• pp.1223-1237
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• 2024

Autonomous vehicles use onboard sensors to sense the surrounding environment. In complex autonomous driving scenarios, the detection and recognition capabilities are constrained, which may result in serious accidents. An efficient way to enhance the detection and recognition capabilities is establishing collaborations with the neighbor vehicles. However, the collaborations introduce additional challenges in terms of the data heterogeneity, communication cost, and data privacy. In this paper, a novel personalized federated learning framework is proposed for addressing the challenges and enabling efficient collaborations in autonomous driving environment. For obtaining a global model, vehicles perform local training and transmit logits to a central unit instead of the entire model, and thus the communication cost is minimized, and the data privacy is protected. Then, the inference similarity is derived for capturing the characteristics of data heterogeneity. The vehicles are divided into clusters based on the inference similarity and a weighted aggregation is performed within a cluster. Finally, the vehicles download the corresponding aggregated global model and train a personalized model which is personalized for the cluster that has similar data distribution, so that accuracy is not affected by heterogeneous data. Experimental results demonstrate significant advantages of our proposed method in improving the efficiency of collaborative perception and reducing communication cost.

• Journal of Information Technology Applications and Management
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• 제15권1호
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• pp.43-65
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• 2008

This study investigates the effects of business environment on the e-business strategy and performance of venture firms. The development of the research model is based on the empirical studies on the strategy literature. The data from the survey was analyzed using Partial Least Squares(PLS). For Daedeok Valley Venture Firms, product innovation differentiation strategy is affected by environmental uncertainty. And, cost leadership strategy tend to be influence by environmental uncertainty. Finally, venture firm's performance is effected by cost leadership strategy and marketing differentiation strategy. However, for in Hsinchu Science Park Venture Firms, product innovation differentiation strategy is affected by environmental uncertainty and heterogeneity. And, marketing differentiation strategy is enhanced by environment uncertainty and industry growth. In addition, cost leadership strategy tend to be influence by environmental uncertainty and heterogeneity. Finally, venture firm's performance is effected by cost leadership strategy and product innovation differentiation strategy.

• International journal of advanced smart convergence
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• 제5권1호
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• pp.16-22
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• 2016

The database integration is being emphasized to one way of the companies collaboration. To database integration, companies are use like one database what their own, it can be provided more efficient service to customer. However, there exist some difficulty to database integration. that is the database security and database heterogeneity problems. In this paper, we proposed the MapReduce based p2p DBaaS hub system to solve database heterogeneity problem. The proposed system provides an environment for companies in the P2P cloud to integrate a database of each other. The proposed system uses DBaaS Hub for a collection of data in the P2P cloud, and use MapReduce for integrating the collected data.