• Journal of Mechanical Science and Technology
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• 제17권4호
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• pp.545-561
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• 2003

We use the first-passage-time formulation by Torquato, Kim and Cule ［J. Appl. Phys., Vol. 85, pp. 1560∼1571 (1999) ］, which makes use of the first-passage region in association with the diffusion tracer's Brownian movement, and develop a new efficient Brownian motion simulation method to compute the effective conductivity of digitized composite media. By using the new method, one can remarkably enhance the speed of the Brownian walkers sampling the medium and thus reduce the computation time. In the new method, we specifically choose the first-passage regions such that they coincide with two, four, or eight digitizing units according to the dimensionality of the composite medium and the local configurations around the Brownian walkers. We first obtain explicit solutions for the relevant first-passage-time equations in two-and three-dimensions. We then apply the new method to solve the illustrative benchmark problem of estimating the effective conductivities of the checkerboard-shaped composite media. for both periodic and random configurations. Simulation results show that the new method can reduce the computation time about by an order of magnitude.

• 대한수학회지
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• 제35권3호
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• pp.727-740
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• 1998

Controlling traffic lights at a bottleneck, in [5] a time of open passage is called optimal, if it minimizes the first moment of the asymptotic distribution of the queue length. The discussion of the first moment as function of the time of open passage is based on an analysis of the behavior of a fixed point when varying control parameters and delivers theoretical and computational aspects of the traffic problem.

• Journal of applied mathematics & informatics
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• 제19권1_2호
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• pp.475-484
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• 2005

Let W(t) be a Wiener path, let $\xi\;:\;[0,\;{\infty})\;\to\;\mathbb{R}$ be a continuous and increasing function satisfying $\xi$(0) > 0, let $$T_{/xi}=inf\{t{\geq}0\;:\;W(t){\geq}\xi(t)\}$$ be the first-passage time of W over $\xi$, and let F denote the distribution function of $T_{\xi}$. Then the first passage problem has a unique continuous solution as following $$F(t)=u(t)+{\sum_{n=1}^\infty}\int_0^t\;H_n(t,s)u(s)ds$$, where $$u(t)=2\Psi(\xi(t)/\sqrt{t})\;and\;H_1(t,s)=d\Phi\;(\{\xi(t)-\xi(s)\}/\sqrt{t-s})/ds\;for\;0\;{\leq}\;s.

• 대한기계학회논문집B
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• 제28권2호
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• pp.189-198
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• 2004

We consider the problem of whether the three-dimensional checkerboard has the connectivity. For this purpose, we first consider the problem of determining the effective conductivity of a checkerboard-shaped composite material by the Brownian motion simulation method. Specifically, we use the efficient first-passage-time technique. Simulation results show that the effective conductivity of the three-dimensional checkerboard increases faster than the two-dimensional counterpart as the contrast between the phase conductivities increases. This implies that the three-dimensional checkerboard's connectivity is stronger than the two-dimensional checkerboard's and thus each phase material of the three-dimensional checkerboard is more likely to be connected than not to be connected.

• Smart Structures and Systems
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• 제2권4호
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• pp.313-320
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• 2006

The reliability analysis of structures subjected to stochastic loading involves evaluation of time and probability of the system's residence in a reference domain. In this paper, we derive an asymptotic estimate of exit time for multi-degrees-of-freedom structural systems. The system's dynamics is governed by the Lagrangian equations with linear dissipation and fast additive noise. The logarithmic asymptotic of exit time is found explicitly as a sum of two terms dependent on kinetic and potential energy of the system, respectively. As an example, we estimate exit time and an associated structural performance for a rocking structure.

• 한국실내디자인학회논문집
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• 제22권3호
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• pp.43-51
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• 2013

The purpose of this study is analysing the characteristics of interior space aiming for the exterior space in mixed-used development. The range of this study is limited as passage, department store, shoppingmall and Mixed Use Development. The method of this study is as follows. First, analysing the 7 samples of the interior space aiming for the exterior space in MXD through the framework of public character categorized as 5 factors, accessibility, openness, comfort properties, connectivity, convenience in use. Second, drawing a conclusion from the precedent step. The result of this study is as follows. First, the interior space has become bigger with time. And the public character is expanded with having the same structure of the city space. Second, the interior space solves the problem of the exterior space of city but prefers the same factors with the exterior space. Third, the street in the interior space has the characteristics of openness and comfort properties through diversification. And the open space is planned in various parts of the MXD and has the character of accessibility and connectivity.

• 한국심리학회지 : 문화 및 사회문제
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• 제21권2호
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• pp.131-158
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• 2015

본 연구는 체육시간이 청소년의 외현화(공격성) 및 내재화(사회적 위축, 우울) 문제에 어떠한 영향을 미치는지, 그리고 그 영향이 시간의 흐름과 성별에 따라 다른지에 대해 분석하였다. 분석 자료로 한국청소년정책연구원(NYPI)에서 실시하는 한국아동·청소년 패널조사(KCYPS)의 중학교 1학년 패널의 2차년도(2011) 데이터(N = 2,133), 3차년도(2012) 데이터(N = 2,151), 4차년도(2013)데이터(N = 1,979)를 활용하였다. 종속변수를 공격성, 사회적 위축, 우울로 설정하고, 독립변수를 성별, 체육시간으로, 통제변수를 학대, 학교적응, 가구연간소득, 보호자 최종학력으로 설정한 뒤 다층성장모형을 적용하여 변인간의 관계를 종단적으로 살펴 본 결과는 다음과 같다. 첫째, 공격성 및 사회적 위축에서 시간의 흐름에 따라 유의한 변화가 있었다. 둘째, 공격성 및 우울에서 성별 차이가 나타났다. 셋째, 체육시간은 우울 및 사회적 위축에만 부적인 영향을 주었다. 넷째, 외현화 및 내재화 문제 모두 시간에 대한 성별의 영향이 변하지 않았다. 다섯째, 시간에 대한 체육시간의 상호작용은 사회적 위축에서만 유의하게 나타났다. 여섯째, 우울에서 체육시간에 대한 성별의 상호작용이 통계적으로 유의하게 나타났다. 이와 같은 연구 결과는 체육시간이 중요하다는 정책적 방향을 제시함으로써 학교 체육시간의 증가를 도모할 수 있는 연구적 기반이 될 것으로 기대해 본다.

• Asian Pacific Journal of Cancer Prevention
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• 제17권sup3호
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• pp.191-195
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• 2016

Breast cancer is the most frequent cancer in females. Its incidence is higher in developed countries than in developing ones partly due to variation in risk exposure and partly due to better detection methods. Scattered evidence in Basrah, Iraq, suggests that breast cancer has been increasing at a significant pace in recent years. This study aimed to measure the current level of risk of breast cancer among females in Basrah and to describe the time trend over almost a decade of years. Data on breast cancer cases from all sources of cancer registration in Basrah governorate were compiled for the years 2005-2012. The data for each year were first checked separately for duplicate reporting of cases among various sources. Then the eight files were pooled together and checked again for any duplicate cases among years of registration. The final set of data contained 2,284 cases of breast cancer (2,213 female cases and 71 male cases). All patients were inhabitants of Basrah governorate at the time of diagnosis. Figures on the Basrah population were obtained from various sources including the Ministry of Health, Ministry of Planning and Developmental Collaboration and local household surveys. It was possible to have total population estimates for each year and by age and sex. The data were imported into SPSS (version 17) software. Age specific and year specific incidence rates were calculated. The age standardized incidence rate was also calculated using world population as the standard population to be 34.9 per 100,000 females. Age-wise, no case was reported among children aged less than 15 years and the incidence increased with advancing age reaching a peak of 123.8/100,000 females at the age range of 50-54 years. The time trend of the crude incidence rate showed only modest increased risk with passage of years and no age shift could be documented in this study. Breast cancer in females in Basrah is a significant health problem. The current incidence rate (crude, 23.7/100,000, age-standardized, 34.9/100,000) is high and justifies intensive efforts to improve early detection of cases, provide better treatment amenities and introduce long term preventive measures. Using the age standardized incidence rate as reported in this paper, it is possible to put the risk in Basrah within a regional and international context.

• 대순사상논총
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• 제24_1권
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• pp.315-349
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• 2014

This paper was carried out to bring the researches on Cultivation Practice of Daesoonjinrihoe which have been at a standstill after analyzing the directions of studies on Cultivation Practice and diagnosing its problems, in addition to that, the paper was also conducted in a way of discussing the research directions in the future. This work enables scholars who have interests in Daesoon Thoughts to easily comprehend over the length and breadth of Cultivation Practice of Daesoonjinrihoe as well as help them understand what level of researches regarding Cultivation Practice has been demanded. Furthermore, this paper will be a step-stone for scholars to ponder how and on what perspective they approach a wide variety of studies on Daesoon Thoughts. The problems reflected on the previous researches on Cultivation Practice are summarized as follows: first, except a few researches in general, problem recognition, research target, style, method, and content are not diverged from the frame defined by Jang Byeong-Gil, who set it up in Daesoon Religion and Thought (Daesoon Jonggyo Sasang) in 1989. Proliferating overlapped researches without developing problem awareness is of great concern. And such researching climate has gradually set in. Secondly, there are numerous researches intending to reveal the researcher's forceful attitude implying faith. Thirdly, most of the previous researches neglect to focus on defining the range of researches. Fourthly, when defining concepts, more thorough insight is needed. Lastly, the researches on analysing symbols and attempting signification analysis are relatively few, only to find many errors. To solve these problems, this paper suggests to develop theories which back up Cultivation Practice by researching on the fields of theory of mind-nature(心性), theory of mind-qi(心氣), theory of pain, Religious Ethics, viewpoint of God/gods, and psychology. Secondly, all the symbols and meanings of elements shown in Cultivation Practice need analyzing more elaborately sophisticatedly and more in-depth. In order to fulfil this goal, by adapting the recent trends of historical studies, it is essential to attempt to engraft Cultivation Practice of Daesoonjinrihoe on cultural phenomena, to analyze thick layers of meanings beneath its surface, to interpret differently, utilizing various perspectives such as focusing on the gender problems, and to extract true meanings out of Cultivation Practice by analyzing everyday events which can occur in real cultivation practices. Thirdly, the terms and concepts regarding Cultivation Practice base the principle themselves. Fourthly, by utilizing methodology of comparative studies on religions, the comparative researches on cultivation practice of different religious traditions are also needed. Lastly, the history of aspects on Cultivation Practice such as transition of mantras, processes which have been conducted through proprieties of prayer and training should be collected and classified. In this context, this work is very important since it helps understand the aspects of transition of originality and characteristics in Cultivation Practice of Daesoonjinrihoe according to passage of time.