• 디지털융복합연구
• /
• 제16권12호
• /
• pp.603-610
• /
• 2018

본 연구의 목적은 청소년 운동선수가 경험하는 운동탈진의 심리적 과정을 알아보기 위해 긍정적 사고와 정체성, 스포츠 행복지각 및 운동탈진의 구조적 관계를 규명하고 긍정적 사고와 운동탈진의 관계에서 정체성과 스포츠행복 지각의 매개효과를 분석하는 것이다. 이러한 연구목적의 달성을 위하여 전국에 소재한 체육 관련, 그리고 일반계열 중 고등학교의 남녀 운동선수를 대상으로 편의표본추출법을 이용하여 총 306부를 최종 유효 표본으로 선정하였다. 자료처리는 SPSS 22.0과 AMOS 22.0을 이용하여 전체모형에서의 적합도 검증 확인 후 가설검정을 하였으며 그 결과는 다음과 같았다. 먼저 긍정적 사고의 주관적 만족과 목표추구는 운동 정체성에 유의한 영향을 미치는 것으로 나타났다. 둘째, 긍정적 사고의 주관적 만족 및 목표추구는 스포츠 행복지각에 모두 영향을 미치지 않는 것으로 나타났다. 셋째. 청소년 선수들의 운동 정체성은 스포츠 행복지각에 정적으로 운동탈진에는 부적인 영향을 미치는 것으로 나타났다. 넷째, 청소년 선수들이 지각하는 스포츠 행복지각은 운동탈진에 부적인 영향을 미치는 것으로 확인되었다. 마지막으로 긍정적 사고의 목표추구와 스포츠행복 지각의 관계에서 운동정체성은 매개역할을 하며, 목표추구와 운동탈진의 관계에서도 운동정체성은 매개역할을 하는 것으로 나타났다.

• 한국정보과학회논문지:소프트웨어및응용
• /
• 제27권1호
• /
• pp.62-73
• /
• 2000

본 논문에서는 기존의 칼라 특성을 이용한 내용 기반 영상 검색 방법을 적용 영역별로 분류 할 수 있는 기준을 제시하고, 그 기준에 의해 영상 내 공간 정보를 충분하게 표현할 수 있어 이동 및 회전 확대/축소 변형에 강한 영상 검색 방법을 제안한다. 일반적으로 칼라 특성을 이용한 내용 기반 영상 검색은 영상 내 공간정보를 충분하게 표현하지 못하여 이동 및 회전, 확대/축소 변형에 약한 단점을 지니고 있다. 이에 기존 연구에서는 인위적으로 영상을 여러 개로 분할하는 방법 등으로 공간 정보를 표현하고자 하였지만 특징 벡터의 수가 급격히 늘어남에 따라 검색 효율이 저하된다는 단점을 가지고있다. 본 논문에서는 기존의 방법을 사용된 칼라 객체의 상호 관계에 따라 1차와 2차 관계에 의한 방법으로 분류하고, 이동, 회전 특히 크기 변화(축소,확대)에 탁월한 성능을 보이는 칼라 객체의 3차 관계를 이용한 방법을 제안한다. 제안된 방법은 주어진 영상으로부터 양자화된 24개의 버킷을 생성해서 각 버킷의 히스토그램의 크기 순서로 세 개 버킷을 선정하고 그들의 평균 칼라 위치를 계산해서 그들 간의 상호 각도를 추출하여 영상의 특징 벡터로 사용하였다. 실험 결과 기존 방법보다 특히 영상의 크기 변화에 대해 좋은 결과를 얻을수 있었으며, 계산량도 적어 효율적임을 보여 주었다.

• The Korean Journal of Physiology
• /
• 제27권2호
• /
• pp.163-174
• /
• 1993

Vertebrate retinal neurons, like brain tracts farm complex synaptic relations in the enter and inner plexiform layers which ape equivalent to the central nervous system nuclei. The effects of $\gamma-aminobutyric$ acid(GABA) and glycine on retinal neurons were explored to discern the mechanisms of action of neurotransmitters. Experiments were performed in the superfused retina-eyecup preparation of the channel catfish, Ictalurus punctatus, using intracellular electrophysiological techniques. The roles of GABA and glycine as inhibitory neurotransmitters are well established in the vertebrate retina. But, we found that the depolarizing action of GABA and glycine on third-order neurons in the catfish retina. GABA and glycine appeared to act on retinal ueurons based on the observations that (1) effects on photoreceptors were not observed, (2) horizontal cells were either hyperpolarized $({\sim}33%)$ or depolarized $({\sim}67%)$, (3) bipolar cells were all hyperpolarized (4) amacrine and ganglion cells were either hyperpolarized $({\sim}37%)$ or depolarized $({\sim}63%)$, (5) GABA and glycine may be working to suppress presynaptic inhibition. The results suggest that depolarization of third-order neurons by GABA and glycine is due to at least two mechanisms; a direct postsynaptic effect and an indirect effect. Therefore, in the catfish retina, a mechanism of presynaptic inhibition or disinhibition including the direct postsynaptic effect may exist in the third-order neurons.

• 한국해양공학회지
• /
• 제17권5호
• /
• pp.39-47
• /
• 2003

A study of the structural strength evaluation on the doubler plate, considering various load cases that were subjected to in-plane and out of plane combined load, has been performed through the systematic evaluation process. In order to estimate the proper static strength of doubler plate for various load cases, elasto-plastic large deflection analysis is introduced, including the contact effect between main plate and doubler. The characteristics of stiffness and strength variation are discussed, based on the results. In order to compare the doubler structure with the original strength of main plate, without doubler, simple formulas for the evaluation of the equivalent flat plate thickness are derived for each load case, respectively, based on the additional series of analysis of flat plate structure. Using these derived equations, the thickness change of an equivalent flat plate is analyzed according to the variation of various design parameters of doubler platesome design guides are suggested in order to maintain the original strength of main plate without doubler reinforcement. Finally, correlation between derived equivalent flat plate formula and the developed buckling strength formulas are discovered, and these relations are formulated for the future development of simple strength evaluation formula of general doubler plate structure.

• Steel and Composite Structures
• /
• 제27권3호
• /
• pp.273-283
• /
• 2018

Nonlinear low velocity impact response of sandwich beam with laminated composite face sheets and soft core is studied based on Extended High Order Sandwich Panel Theory (EHSAPT). The face sheets follow the Third order shear deformation beam theory (TSDT) that has hitherto not reported in conventional EHSAPT. Besides, the two dimensional elasticity is used for the core. The nonlinear Von Karman type relations for strains of face sheets and the core are adopted. Contact force between the impactor and the beam is obtained using the modified Hertz law. The field equations are derived via the Ritz based applied to the total energy of the system. The solution is obtained in the time domain by implementing the well-known Runge-Kutta method. The effects of boundary conditions, core-to-face sheet thickness ratio, initial velocity of the impactor, the impactor mass and position of the impactor are studied in detail. It is found that each of these parameters have significant effect on the impact characteristics which should be considered. Finally, some low velocity impact tests have been carried out by Drop Hammer Testing Machine. The contact force histories predicted by EHSAPT are in good agreement with that obtained by experimental results.

• 대한조선학회논문집
• /
• 제40권6호
• /
• pp.37-48
• /
• 2003

A study for the structural strength evaluation of doubler plates subjected to the in-plane combined load and lateral pressure load has been performed through a systematic evaluation process. In order to properly estimate the static strength of doubler plate, elasto-plastic large deflection analysis is introduced including the contact effect between main plate and doubler. The characteristics of stiffness and strength variation are discussed based on the analysis results. Also, in order to compare the doubler structure with the original strength of main plate without doubler, a simple formula for the evaluation of the equivalent flat plate thickness is derived based on the additional series analysis of fiat plate structure. Using this derived equation, the thickness change of a equivalent flat plate is analyzed according to the variation of various design parameters of doubler plate and some design guides are suggested In order to maintain the original strength of main plate without doubler reinforcement. Finally, correlation between derived equivalent plate thickness formula and the developed buckling strength formulas for intact plates by author et al. is discovered and these relations are formulated for the future development of simple strength evaluation formula of doubler plate structure.

• 한국전산구조공학회논문집
• /
• 제20권6호
• /
• pp.789-799
• /
• 2007

본 논문에서는 구조의 재료물성치와 기하학적 인수의 공간적 불확실성에 의한 구조 응답변화도 산정을 위한 정식화를 제안하였다. 정식화는 추계론적 유한요소해석의 해석법 중의 하나인 가중적분법을 기본으로 하였다. 해석 대상 구조는 전단변형을 포함하는 평판구조로서, 평판구조에 나타날 수 있는 불확실 인수로는 재료적 측면에서는 재료탄성계수와 포아송비가 있으며, 기하학적 인수로는 평판의 두께를 들 수 있다. 선형탄성 영역에서 선형성을 나타내는 재료탄성계수와는 달리 평판의 두께는 3차함수로 강성에 기여하고, 포아송비의 경우 분수의 형태로 강성에 기여하므로 직접적으로는 이를 추계론적 해석에 고려할 수 없다. 따라서 본 연구에서는 적합행렬내의 포아송비를 Taylor전개하여 사용하였다. 제안된 정식화에 의한 결과는 기존 연구결과는 물론 몬테카를로 해석에 의한 결과와도 비교하여 제안한 정식화를 검증하였다.

• Structural Engineering and Mechanics
• /
• 제23권5호
• /
• pp.455-468
• /
• 2006

Smart structural systems are defined as ones that demonstrate the ability to modify their characteristics and/or properties in order to respond favorably to unexpected severe loading conditions. The performance of such a task requires a set of additional components to be integrated within such systems. These components belong to three major categories, sensors, processors and actuators. It is wellknown that all structural systems entail some level of uncertainty, because of their extremely complex nature, lack of complete information, simplifications and modeling. Similarly, sensors, processors and actuators are expected to reflect a similar uncertain behavior. As it is imperative to be able to evaluate the impact of such components on the behavior of the system, it is as important to ensure, or at least evaluate, the reliability of such components. In this paper, a system model for reliability assessment of smart structural systems is outlined. The presented model is considered a necessary first step in the development of a reliability assessment algorithm for smart structural systems. The system model outlines the basic components of the system, in addition to, performance functions and inter-relations among individual components. A fault tree model is developed in order to aggregate the individual underlying component reliabilities into an overall system reliability measure. Identification of appropriate limit states for all underlying components are beyond the scope of this paper. However, it is the objective of this paper to set up the necessary framework for identifying such limit states. A sample model for a three-story single bay smart rigid frame, is developed in order to demonstrate the proposed framework.

• 한국정보처리학회논문지
• /
• 제6권3호
• /
• pp.781-791
• /
• 1999

DD(Decision Diagrams) is an efficient operational data structure for an optimal expression of boolean functions. In a graph-based synthesis using DD, the goal of optimization decreases representation space for boolean functions. This paper represents boolean functions using OPKFDD(Ordered Pseudo-Kronecker Functional Decision Diagrams) for a graph-based synthesis and is based on the number of nodes as the criterion of DD size. For a property of OPKFDD that is able to select one of different decomposition types for each node, OPKFDD is variable in its size by the decomposition types selection of each node and input variable order. This paper proposes a method for generating OPKFDD efficiently from the current BDD(Binary Decision Diagram) Data structure and an algorithm for minimizing one. In the multiple output functions, the relations of each function affect the number of nodes of OPKFDD. Therefore this paper proposes a method to decide the input variable order considering the above cases. Experimental results of comparing with the current representation methods and the reordering methods for deciding input variable order are shown.

• Advances in nano research
• /
• 제13권1호
• /
• pp.29-45
• /
• 2022

The optimization for dynamic response associated with a cylindrical shell which is made of laminated composites embedded in a piezoelectric layer which is subjected to temperature rises and is resting on an elastic foundation is investigated for the first time. The first shear order theory (FSDT) is utilized in order to obtain the strain relations of the shell. Then, using the energy method, the equations of motions as well as boundary condition of the problem are attained. The formulation of this study together with the solution procedure which is a numerical solution method, differential quadrature method (DQM) is validated using other researches. This paper presents a thorough study on the parameters which impacts the vibration frequency of the laminated shell. The results of this paper shows that any type of laminated composite shell can reduce the vibration frequency providing that the angle related to layer are higher than 85 degrees. Also, in order to reduce the effect of temperature rises, the laminated composites instead of orthotropic one can be used.