• 보건교육건강증진학회지
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• 제30권5호
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• pp.177-188
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• 2013

Objectives: The purpose of this study was to evaluate the feeling of distance of social work practitioners for people living with HIV/AIDS(PLWHA) and to identify related factors. Methods: A total of 409 data were collected as convenience sampling from social welfare service providers. Independent variables were socio-demographic data, AIDS related knowledge, authoritarian personality, prejudice for minority(handicapped, women, foreigner, old aged), cultural competency. Data were analyzed by t-test, ANOVA, multiple regression analysis were conducted. Results: Multiple regression model was developed by integrating the significant variables from univariate analysis. Significant factors of physical distance were social prejudice against handicapped, knowledge about AIDS and critical awareness/knowledge about other culture. And significant factors of social distance were social prejudice against handicapped, knowledge about AIDS, authoritarian personality, critical awareness/knowledge about other culture. At last, we found that social prejudice against handicapped was the biggest factor for physical distance and authoritarian personality was the biggest factor for social distance of social work practitioners. Conclusions: The area of social services for PLWHA have to be expanded. Physical and social distance of professionals to provide services to PLWHA and factors affecting it is necessary to continue research. In addition, on the basis of these findings, specific training programs is need to be developed.

• 융합정보논문지
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• 제10권4호
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• pp.89-97
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• 2020

본 연구는 교육 콘텐츠의 효율적인 지역화 및 국제화를 위해 한국 학습자에 대한 기초자료를 제공하고자, 학교 내 권력거리에 대한 대학생들의 인식을 탐색하였고, 이러한 인식이 교수-학생 상호작용, 도움요청, 비판적 사고, 융합적 사고에 미치는 영향을 알아보았다. 416명의 대학생들이 온라인 설문에 참여하였다. 학교 내 권력거리를 수업 주도자, 교사의 역할, 교사-학생 동등성의 세 영역으로 구분하여 분석하였고, 큰 권력거리의 경향성을 확인하였다. 또한, 큰 권력거리가 교수-학생 상호작용, 도움요청, 비판적 사고, 융합적 사고에 긍정적인 영향을 미치는 것을 확인하였다. 연구 결과를 바탕으로 국제적인 교육 콘텐츠의 한국 학습자 대상 맞춤형 지역화를 위한 고려사항에 대해 논의하였다. 마지막으로, 연구의 제한점과 후속 연구방향에 대해 제언하였다.

• 한국게임학회 논문지
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• 제13권6호
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• pp.27-34
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• 2013

본 논문은 동물들의 집단행동에서 나타나는 포식자-희생자 관계에서 포식자에 대한 희생자의 추격회피 행동을 분석한다. 희생자가 포식자의 추격을 피하는 하나의 방법이 인접거리에서 급회전을 하는 것이다. 그때 희생자가 추격으로부터 살아남기 위해서는 임계거리와 회전각은 매우 중요하다. 여기서 임계거리는 회전 시작 직전 포식자와 희생자 사이의 거리이다. 이러한 임계거리와 회전각을 분석하기 위하여 본 논문은 추격의 시작에서 보유한 포식자의 에너지와 추격동안 소비한 포식자의 에너지를 이용한다. 시뮬레이션을 통하여, 임계거리가 짧을수록 희생자가 추격으로부터 살아남을 수 있는 회전각은 커진다는 것과 포식자의 질량에 대한 희생자의 질량의 비율이 작아지는 경우에도 역시 회전각 커진다는 것을 알 수 있었다. 시뮬레이션 결과는 자연에서 나타나는 현상과 유사하며, 따라서 이것은 본 논문에서 분석한 방법이 옳다는 것을 의미한다.

• Journal of Magnetics
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• 제20권1호
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• pp.11-20
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• 2015

In this work, Monte Carlo simulation was employed to model the stretchable Ising monolayer film to investigate the effect of the spatial distance variation among magnetic atoms on magnetic behavior of the film. The exchange interaction was considered as functions of initial interatomic distance and the stretched distance (or the strain). Following Bethe-Slater picture, the magnetic exchange interaction took the Lennard-Jones potential-like function. Monte Carlo simulations via the Wolff and Metropolis algorithms were used to update the spin systems, where equilibrium and dynamic magnetic profiles were collected. From the results, the strain was found to have strong influences on magnetic behavior, especially the critical behavior. Specifically, the phase transition point was found to either increase or decrease depending on how the exchange interaction shifts (i.e. towards or away from the maximum value). In addition, empirical functions which predict how the critical temperatures scale with initial interatomic distance and the strain were proposed, which provides qualitatively view how to fine tune the magnetic critical point in monolayer film using the substrate modification induced strain.

• 한국ITS학회 논문지
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• 제16권1호
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• pp.90-100
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• 2017

보행자와 승용차의 충돌위치에 따른 전도 거리 변화를 madymo-시뮬레이션을 통하여 분석하였다. 충돌위치를 차량중심으로부터 바깥쪽으로 2.5cm간격마다 충돌하는 경우에 대하여 시뮬레이션하였다. 그 결과 보행자의 전도거리형태가 급격히 변화하는 임계점이 두 곳에서 나타났다. 첫 번째 임계점은 보행자의 어깨가 차량과 접촉되지 않는 위치였다. 두 번째 임계점의 위치는 보행자의 무게중심이 차체의 외곽선상을 벗어나기 직전의 위치였다. 첫째 임계점과 두 번째 임계점의 사이 구간에서는 충돌위치가 차량의 바깥쪽에 가까울수록 전도거리는 급격히 감소하였다. 두 임계점 사이를 벗어난 구간에서는 전도거리 변화가 크지 않은 것으로 나타났다. 충돌위치에 따른 전도거리 변화가 밝혀져서 보다 정확한 교통안전 분석과 보행자 사고해석이 가능해질 것으로 판단된다.

• Structural Engineering and Mechanics
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• 제66권5호
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• pp.583-594
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• 2018

A theoretical formulation based on the linearized potential theory, the Descartes' rule and the extremum optimization method is presented to calculate the critical distance of lifting points of the fully balanced hoist vertical ship lift, and to study pitching stability of the ship lift. The overturning torque of the ship chamber is proposed based on the Housner theory. A seven-free-degree dynamic model of the ship lift based on the Lagrange equation of the second kind is then established, including the ship chamber, the wire rope, the gravity counterweights and the liquid in the ship chamber. Subsequently, an eigenvalue equation is obtained with the coefficient matrix of the dynamic equations, and a key coefficient is analyzed by innovative use of the minimum optimization method for a stability criterion. Also, an extensive influence of the structural parameters contains the gravity counterweight wire rope stiffness, synchronous shaft stiffness, lifting height and hoists radius on the critical distance of lifting points is numerically analyzed. With the Runge-Kutta method, the four primary dynamical responses of the ship lift are investigated to demonstrate the accuracy/reliability of the result from the theoretical formulation. It is revealed that the critical distance of lifting points decreases with increasing the synchronous shaft stiffness, while increases with rising the other three structural parameters. Moreover, the theoretical formulation is more applicable than the previous criterions to design the layout of the fully balanced hoist vertical ship lift for the ensuring of the stability.

• 한국전자파학회논문지
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• 제24권2호
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• pp.168-179
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• 2013

4-코일 자기 공진 무선 전력 전송 시스템의 해석법 중 critical point analysis(CA)와 impedance matching analysis(IA)를 분석하고, 두 결과를 비교하였다. 4-코일 시스템은 가까운 거리에서는 주파수 분리 현상이 나타나고, 먼 거리에서는 효율이 급격히 감소하는 특징을 나타낸다. 따라서 고정된 주파수에서 사용할 경우, 목표하는 거리와 효율에 따라 최적화가 필요하다. CA는 전체 거리에서 효율이 최대가 되는 critical point를 이용하여 최적화하는 방법이고, IA는 목표 지점에서 임피던스 정합을 이뤄 최대 효율을 만족시키는 방법이다. 기존의 해석은 두 가지 방법을 비교하고 시스템 특성을 이해하는데 부족한 점이 있었기 때문에, 본 논문에서 두 방법의 이론을 좀 더 자세히 분석하고 비교하였다. 두 방법의 비교 결과를 통해 IA가 더 우수함을 보였다. 또한, 한쪽만 정합할 경우 발생되는 트레이드-오프에 대해서도 설명하였다. 스파이럴 공진 코일을 이용한 실험에서는 이론 결과와 동일한 결과를 얻을 수 있었다.

• 한국연소학회지
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• 제13권4호
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• pp.26-36
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• 2008

Experimental study is conducted to identify the existence of a shrinking flame disk and to clarify its flame characteristics through the inspection of critical mole fraction at flame extinction and edge flame oscillation at low strain rate flames. Experiments are made as varying global strain rate, velocity ratio, and burner distance. The transition from a shrinking flame disk to a flame hole is verified through gradient measurements of maximum flame temperature. The evidence of edge flame oscillation in flame disk is also provided through numerical simulation in microgravity. It is found at low strain rate flame disks in normal gravity that buoyancy effects are importantly contributing to lateral heat loss to burner rim, and is proven through critical mole fraction at flame extinction, edge flame oscillation, and measurements of flame temperature gradient along flame disk surface.

• Journal of the Optical Society of Korea
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• 제9권1호
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• pp.6-12
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• 2005

The perturbation approach is applied to solve the nonlinear Schrodinger equation, and its valid range has been determined by comparing with the results of the split-step Fourier method over a wide range of parameter values. With γ= 2㎞/sup -1/mW/sup -1/, the critical distance for the first order perturbation approach is estimated to be(equation omitted). The critical distance, Z/sub c/, is defined as the distance at which the normalized square deviation compared to the split-step Fourier method reaches 10/sup -3/. Including the second order perturbation will increase Z/sub c/ more than a factor of two, but the increased computation load makes the perturbation approach less attractive. In addition, it is shown mathematically that the perturbation approach is equivalent to the Volterra series approach, which can be used to design a nonlinear equalizer (or compensator). Finally, the perturbation approach is applied to obtain the sinusoidal response of the fiber, and its range of validity has been studied.

• Bulletin of the Korean Chemical Society
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• 제19권10호
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• pp.1063-1068
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• 1998

The nature of F electronic excitation energy transfer to OH- vibrational levels in KCl crystals is the exchange interaction, although the transfer process exhibits three temporally distinguishable components depending on the distance between excited F center and OH-. The critical distance as well as rate of the major energy transfer process in randomly distributed samples increases rapidly as OH- librational motions become active with temperature rise. The excited state character introduced into the OH- ground electronic state by perturbation is essential for the exchange interaction. The perturbation is brought about by the expanded electron cloud of excited F center for OH- associated to F center, whereas by librations and lattice vibrations perpendicular to the bond axis for isolated OH- . F excitation quenching efficiency by OH- is dependent on the variation of the critical distance rather than the rate as the rate is much faster than the normal F bleach recovery rate.