• 아동학회지
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• 제36권4호
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• pp.1-16
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• 2015

The purpose of this study was to examine the bidirectional relationship between the negative emotionality of 0-to 3-year-old and maternal parenting styles, focusing on warmth and reactivity. Four waves of panel data from the Korean Children Panel Study(KCPS) were analyzed in this study by means of autoregressive cross-lagged modeling. The results of this study were as follows. First, negative emotionality and maternal parenting styles were consistently stable for 0-to 3-year-old. Second, a bidirectional relationship between negative emotionality and maternal warmth parenting styles was confirmed according to the appearance of both parent and child effects. In other words, higher levels of negative emotionality was associated with lower maternal warmth parenting styles across time and in both directions. Additionally, the relationship between negative emotionality and maternal reactivity parenting styles were partially identified as being bidirectional in nature, whilst also being related to age. These findings suggested that parent education aimed at strengthening parenting skills, and programs designed to relieve negative emotionality of 0-to 3-year-olds are clearly needed.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제10권4호
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• pp.253-258
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• 2010

The causal network represents the knowledge related to the dependency relationship between all attributes. If the causal network is available, the dependency relationship can be employed to estimate the missing values for improving the estimation performance. However, the previous method had a limitation in that it did not consider the bidirectional characteristic of the causal network. The proposed method considers the bidirectional characteristic by applying prior and posterior conditions, so that it outperforms the previous method.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2006년도 추계학술발표회
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• pp.181-186
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• 2006

정지궤도위성은 태양 궤도위성과는 달리 넓은 지역의 매시간 측정이 가능하다. 정지 위성은 관측영역은 항상 고정되어 있으나 태양의 위치가 항상 변하므로 한 주어진 지점의 해수 신호의 크기는 기간에 따라 변하게 된다. 반면에 태양 궤도 위성은 하루 통일한 시간대에서 동일한 영역을 촬영하기 때문에 신호의 크기의 변화가 없다. 즉, 정지해양 위성에서 관측된 신호의 크기는 태양과 위성이 항상 수직 방향에 위치한다고 가정할 때 얻어지는 신호의 크기로 변경되어야한다. 이와 같은 신호의 보정은 지속적으로 변화하는 태양, 위성과 관측점의 기하학적인 위치변화에 따라 나타나게 되는데 이를 양방향 계수 (Bidirectional Factor) 라고 한다. 본 연구에서는 태양의 위치와 기하학적인 요인을 계산, 대기권 밖의 총 방사휘도와 반사율을 계산하였다. 그리고 양방향계수, 즉 관측점과 관측지점 사이의 규격화된 해면방사휘도$([L_W]_N)$의 비를 모의실험을 통해 확인하였다. 1년간의 값을 영상화 하였고 보다 정확한 양방향 계수 (Bidirectional Factor)를 얻기 위해 다양한 조건의 모의실험의 필요성을 제시하였다.

• Journal of applied mathematics & informatics
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• 제9권1호
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• pp.349-357
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• 2002

In this paper, we analyze queueing behaviors and investigate the possibilities of reducing and controlling shortages and oversupplies in the bidirectional queueing system which forms a negative queue by demand and a positive queue by supply. Interarrival times of units in the bidirectional queueing system investigated are exponetially distributed. Instant pairing off implies that queue can be either positive or negative, but not both at the same time. The results include a proof that sum of queue lengths is minimized if rates of demand and supply in each system are equal and optimum solutions for rates of supply which minimize the sum of queue lengths when rates of demand and sum of rates of supply are given. In addition, the relationship between the ordinary queueing system and the bidirectional queueing system is investigated.

• 제어로봇시스템학회논문지
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• 제19권5호
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• pp.410-415
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• 2013

This paper proposes a bidirectional platoon control law using a coupled distance error based on the backstepping-like feedback linearization control method for an interconnected mobile agent system with a string structure. Unlike the previous results where the single agent was controlled using the only own information without other agents, the proposed control law cannot show the only distance error convergence of each agent, but also the string stability of the whole system. Also, the control performances are improved by the proposed control law in spite of low performance of bidirectional control strategy in the previous results. The proposed bidirectional platoon control algorithm is based on the backstepping-like feedback linearization control method. The position errors between each agent and the preceding and the behind agents are coupled by weighted summation. By the proposed control law, the distance error of each agent can converge to zero while the string stability is guaranteed when the coupled errors can converge to zero. To this end, the back-stepping control method is employed. The pseudo velocity input is determined considering the kinematic relationship between agents and the string stability. Then, the actual dynamic control input is determined to make the actual velocity converge to the pseudo velocity input. The stability analysis and the simulation results of the proposed method are included in order to demonstrate the practical application of the proposed algorithm.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
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• pp.79-81
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• 2006

Geostationary ocean satellite, unlike other sun-synchronous polar-orbit satellites, will be able to take a picture of a large region several times a day (almost with every one hour interval). For geostationary satellite, the target region is fixed though the location of sun is changed always. Thus, the ocean signal of a given target point is largely dependent on time. In other words, the ocean signal detected by geostationary satellite sensor must translate to the signal of target when both sun and satellite are located in nadir, using another correction model. This correction is performed with a standardization of signal throughout relative geometric relationship among satellite - sun - target points. One signal value of a selected pixel point of the target region of Geostationary Ocean Colour Imager (GOCI) would be set up as a standard, and the ratio of all remained pixel point can be calculated. This relative ratio called bidirectional factor, the result of modelling of spatiotemporal variation of bidirectional factor is shown.

• The Journal of Asian Finance, Economics and Business
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• 제4권1호
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• pp.25-38
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• 2017

This study investigates the causal relationship between stock prices and exchange rates for six Middle Eastern countries, namely, Egypt, Iran, Jordan, Kuwait, Oman, and Saudi Arabia before and during (after) the 2007 global financial crisis for the period between January 2004 and September 2015. The sample is divided into two sub-periods, that is, the period from January 1, 2004 to September 30, 2007 and the period from October 1, 2007 to September 30, 2015, to represent the pre-crisis period and the post-crisis period, respectively. Using Vector Autoregressive (VAR) model in a multivariate framework (including two control variables, inflation rates and oil prices) the results suggest that in the case of Jordan, Kuwait and Saudi Arabia, there exists bidirectional causalities after the crisis period but not the before. The opposite status is available for the case of Iran. In the case of Oman, there is bidirectional causality between the variables of interest in both periods. The results also reveal that the relationship between stock prices and exchange rates has become stronger after the 2007 global financial crisis. Overall, the results of this study indicate that fluctuations in foreign exchange markets can significantly affect stock markets in the Middle East.

• 문화기술의 융합
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• 제9권3호
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• pp.281-286
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• 2023

본 연구는 서울, 서울 강남, 서울 강북을 대상으로 주택 매매가격과 전세가격의 인과관계를 분석하였다. 시간불변 그랜져 인과성 검정을 통해 분석한 결과, 서울과 강북 지역에서는 매매가격과 전세가격이 양방향 인과성이 있는 것으로 분석된 반면, 강남은 양방향으로 인과성이 없는 것으로 분석되었다. 반면, 시간가변 그랜저 인과성 검정을 통해 분석한 결과에서는 서울, 강남, 강북 지역 모두 1993년 이후 전기간 동안 주택 전세가격은 매매가격에 그랜저 인과관계가 있는 것으로 분석된 반면, 전세가격에 대한 매매가격의 그랜저 인과성이 발견된 빈도는 그 역에 비해 적었다. 특징적인 것은 강남 지역은 2010년 이후 전세가격이 매매가격에 대해 지속적으로 그랜저 인과하는 것으로 분석되었다는 것이다. 이와 같은 분석 결과는 매매시장과 전세시장이 양방향으로 강한 영향을 주고받는 구조에서 전세시장에 대한 유동성 공급 확대는 주택시장 전반에 걸쳐 변동성을 확대할 수 있음을 시사한다.

• 대한가정학회지
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• 제38권5호
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• pp.15-24
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• 2000

The purpose of the study was to explore the causal relationships between delinquency and self-esteem among adolescents. The subjects of this study were 497 adolescents attending middle schools in Pusan. The data was collected by longitudinal research design of 9 month interval In first, second wave, the participants completed the delinquency scale and the multidimensional self-esteem inventory that includes home self, peer-related self, teacher-related self, academic-general serif, physical appearance self, physical competence self, and personality self, respectively The major findings of this study were as follows: these causal relationships differed among subdimensions of self-esteem, 1)the causal relationship between delinquency and home self was bidirectional, 2)the causal relationship between delinquency and peer-related self, teacher-related self, academic-general self, and personality self was unidirectional, 3)the causal relationship between delinquency and physical appearance self, physical competence self was not statistically significant.

• 한국기술혁신학회:학술대회논문집
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• 한국기술혁신학회 2004년도 춘계학술대회
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• pp.77-97
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• 2004

In this paper we: (1) analyze the relationship among public R&D investment, private R&D investment, and GDP by employing the Granger causality test; (2) examine if there is any country-specific pattern in the relationship by testing the cases of Korea, the U.S. and Japan. We found some common results for the above countries as follows: (i) GDP causes Public R&D, not vice versa; (ii) Private R&D causes GDP; and (iii) Public R&D does not cause Private R&D. For the bivariate model of GDP and total R&D, the results show the existence of one-way causality running from total R&D to GDP for both U.S, and Japan. We also found bidirectional causal relationship between GDP and total R&D for Korea, which could be interpreted as a typical pattern for newly industrialized countries.