• 대한수학회지
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• 제57권6호
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• pp.1551-1571
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• 2020

This paper is concerned with the following Kirchhoff-Schrödinger-Poisson system $$\begin{cases} -(a+b{\displaystyle\smashmargin{2}\int\nolimits_{\mathbb{R}^3}}{\mid}{\nabla}u{\mid}^2dx){\Delta}u+V(x)u+{\mu}{\phi}u={\lambda}f(x){\mid}u{\mid}^{p-2}u+g(x){\mid}u{\mid}^{p-2}u,&{\text{ in }}{\mathbb{R}}^3,\\-{\Delta}{\phi}={\mu}{\mid}u{\mid}^2,&{\text{ in }}{\mathbb{R}}^3, \end{cases}$$ where a > 0, b, µ ≥ 0, p ∈ (1, 2), q ∈ [4, 6) and λ > 0 is a parameter. Under some suitable assumptions on V (x), f(x) and g(x), we prove that the above system has at least two different nontrivial solutions via the Ekeland's variational principle and the Mountain Pass Theorem in critical point theory. Some recent results from the literature are improved and extended.

• Structural Engineering and Mechanics
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• 제28권5호
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• pp.587-601
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• 2008

In this study, a numerical procedure based on the finite element method for materially and geometrically nonlinear analysis of reinforced and prestressed concrete slender columns with arbitrary section subjected to combined biaxial bending and axial load is developed. In order to overcome the low computer efficiency of the conventional section integration method in which the reinforced concrete section is divided into a large number of small areas, an efficient section integration method is used to determine the section tangent stiffness. In this method, the arbitrary shaped cross section is divided into several concrete trapezoids according to boundary vertices, and the contribution of each trapezoid to section stiffness is determined by integrating directly the trapezoid. The space frame flexural theory is utilized to derive the element tangent stiffness matrix. The nonlinear full-range member response is traced by an updated normal plane arc-length solution method. The analytical results agree well with the experimental ones.

• Interaction and multiscale mechanics
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• 제1권3호
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• pp.317-328
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• 2008

When carbon-filled rubber specimens are subjected to cyclic loading, they do not return to their initial state after loading and subsequent unloading, but exhibit a residual strain or permanent deformation. We propose a specific form of the pseudo-elastic energy function to represent cyclic loading for incompressible, isotropic materials with stress softening and residual strain. The essence of the pseudo-elasticity theory is that material behaviour in the primary loading path is described by a common elastic strain energy function, and in unloading, reloading or secondary unloading paths by a different strain energy function. The switch between strain energy functions is controlled by the incorporation of a damage variable into the strain energy function. An extra term is added to describe the permanent deformation. The finite element implementation of the proposed model is presented in this paper. All parameters in the proposed model and elastic law can be easily estimated based on experimental data. The numerical analyses show that the results are in good agreement with experimental data.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제21권3호
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• pp.147-163
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• 2014

In this paper, we study the existence of positive solutions for singular impulsive differential equations with integral boundary conditions $$\{u^{{\prime}{\prime}}(t)+q(t)f(t,u(t),u^{\prime}(t))=0,\;t{\in}\mathbb{J}^{\prime},\\{\Delta}u(t_k)=I_k(u(t_k),u^{\prime}(t_k)),\;k=1,2,{\cdots},p,\\{\Delta}u^{\prime}(t_k)=-L_k(u(t_k),u^{\prime}(t_k)),\;k=1,2,{\cdots},p,\\u=(0)={\int}_{0}^{1}g(t)u(t)dt,\;u^{\prime}=0,$$) where the nonlinearity f(t, u, v) may be singular at v = 0. The proof is based on the theory of Leray-Schauder degree, together with a truncation technique. Some recent results in the literature are generalized and improved.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 A
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• pp.337-339
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• 1995

A Linear Induction Machine(LIM) is the motor which is developed from an rotary induction machine. Usually, the electromagnetic field of an LIM is analyzed by Maxwell's equations. The structure of an LIM is different from a conventional rotary machine, an LIM has some particular characteristics such as the end effects. Hence, the mathematical analysis of an LIM is very complicated and the implementation of the equivalent model is difficult. In this paper, the dynamic equations and the equivalent model of a Double-sided short primary LIM(DLIM) is obtained by the winding function and a d-q theory. The validity of the proposed methodology is verified by numerical analysis.

• 대한한방체열의학회지
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• 제2권1호
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• pp.11-16
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• 2003

Purpose D.I.T.I. can be used to diagnose the dysmenorrhea and prove the Oriental Medical Theory and the Sasang Constitutional Medicine concerning Dysmenorrhea. According to the Sasang Constitutional Medicine, we chose 39 dysmenorrhea patients (Soeumin 26 Patients, Taeumin 13 Patients) and expremented D.I.T.I. to find difference of chilliness and fever in the upper part of body and the lower part of body. Methods We expremented 39 dysmenorrhea patients chosena expremental group from Apr 1. 2002 to May 30, 2002. We diagnosed the constitution by Q.S.C.C. and selected six acu-points CV-17, CV-12, CV-4, G-21, B-15 and B-23. To appraise difference of temperature according to constitution we compared skin temperature of front to back. Result Mean Absolute Value of ${\Delta}T$ in body (front and back) shows significant difference. Totally the temperature of front is higher than the temperature of back. the temperature of Soeumin is higher than the temperature of Taeumin in whole. Conciusion Especially the upper abdomen area(CV-17) shows high temperature in 39 dysmenorrhea patients, the lower abdomen area (CV-4) of Soeumin shows lower temperature relatively.

• Safety and Health at Work
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• 제9권1호
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• pp.115-124
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• 2018

Background: Substantial empirical research has shown conflicting results regarding the influence of organizational external factors on construction risk management, suggesting the necessity to introduce a moderator into the study. The present research confirmed whether rules and regulations matter on the relationships between organizational external factors and construction risk management. Methods: Based on discouragement and organizational control theory, this research examined the effects of organizational external factors and rules and regulations on construction risk management among 238 employees operating in construction companies in Abuja and Lagos, Nigeria. A personally administered questionnaire was used to acquire the data. The data were analyzed using partial least squares structural equation modeling. Results: A significant positive relationship between organizational external factors and construction risk management was asserted. This study also found a significant positive relationship between rules and regulations and construction risk management. As anticipated, rules and regulations were found to moderate the relationship between organizational external factors and construction risk management, with a significant positive result. Similarly, a significant interaction effect was also found between rules and regulations and organizational external factors. Implications of the research from a Nigerian point of view have also been discussed. Conclusion: Political, economy, and technology factors helped the construction companies to reduce the chance of risk occurrence during the construction activities. Rules and regulations also helped to lessen the rate of accidents involving construction workers as well as the duration of the projects. Similarly, the influence of the organizational external factors with rules and regulations on construction risk management has proven that most of the construction companies that implement the aforementioned factors have the chance to deliver their projects within the stipulated time, cost, and qualities, which can be used as a yardstick to measure a good project.

• Smart Structures and Systems
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• 제9권3호
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• pp.231-251
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• 2012

The stochastic optimal control for a piezoelectric spherically symmetric shell subjected to stochastic boundary perturbations is constructed, analyzed and evaluated. The stochastic optimal control problem on the boundary stress output reduction of the piezoelectric shell subjected to stochastic boundary displacement perturbations is presented. The electric potential integral as a function of displacement is obtained to convert the differential equations for the piezoelectric shell with electrical and mechanical coupling into the equation only for displacement. The displacement transformation is constructed to convert the stochastic boundary conditions into homogeneous ones, and the transformed displacement is expanded in space to convert further the partial differential equation for displacement into ordinary differential equations by using the Galerkin method. Then the stochastic optimal control problem of the piezoelectric shell in partial differential equations is transformed into that of the multi-degree-of-freedom system. The optimal control law for electric potential is determined according to the stochastic dynamical programming principle. The frequency-response function matrix, power spectral density matrix and correlation function matrix of the controlled system response are derived based on the theory of random vibration. The expressions of mean-square stress, displacement and electric potential of the controlled piezoelectric shell are finally obtained to evaluate the control effectiveness. Numerical results are given to illustrate the high relative reduction in the root-mean-square boundary stress of the piezoelectric shell subjected to stochastic boundary displacement perturbations by the optimal electric potential control.

• 한국융합학회논문지
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• 제6권3호
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• pp.1-12
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• 2015

본 연구의 목적은 응급처치교육을 받은 대상자들이 인식하는 응급처치에 대한 인식 유형별 차이를 이해하여, 이에 따른 응급처치와 관련된 교육내용 및 교육방법과 응급처치 관련 실무 중재 방안 개발의 기초를 제공하는 데 있다. 본 연구방법은 J지역에 있는 일반인과 의료인 중 응급처치 교육을 받은 48명을 P-표본으로 추출하여 30개의 진술문을 사용해 자료분석은 PC QUANL program으로 처리하였다. 자료수집은 2010년 3월부터 2010년 7월까지하였다. 응급처치에 대한 일반인의 인식유형은 3개의 유형이 나타났다. 제1유형은 '시간 중시형', 제2유형은 '최초 반응자 중시형', 제3유형은 '융합교육 중시형', 제4유형은 '일반인 가능성형'으로 나타났다. 본 연구결과 응급처치 유형에 따른 개별화되고 단계적인 교육방법과 중재방안의 개발이 필요함을 알 수 있다.

• 한국군사과학기술학회지
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• 제21권3호
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• pp.295-305
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• 2018

We present a passively Q-switched monolithic Er:Yb:glass microchip laser developed in our lab. The microchip laser can produce pulses at 1535 nm of the 'eye-safe' wavelengths with the pulse energy of 50 uJ and the pulse width of 4-6 ns. Using the laser we also designed and developed a pulsed Er:Yb:glass microchip laser rangefinder. Expressions for background and signal power, noise, and signal-to-noise ratio are reviewed. A computer simulation was used to optimize laser power, receiver aperture, and preamplifier bandwidth for the efficient system design of the laser rangefinder. Experimental results are presented to compare with the theory.