• Structural Engineering and Mechanics
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• v.44 no.1
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• pp.109-125
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• 2012

Post-buckling behavior of Timoshenko beams subjected to uniform temperature rising with temperature dependent physical properties are studied in this paper by using the total Lagrangian Timoshenko beam element approximation. The beam is clamped at both ends. In the case of beams with immovable ends, temperature rise causes compressible forces end therefore buckling and post-buckling phenomena occurs. It is known that post-buckling problems are geometrically nonlinear problems. Also, the material properties (Young's modulus, coefficient of thermal expansion, yield stress) are temperature dependent: That is the coefficients of the governing equations are not constant in this study. This situation suggests the physical nonlinearity of the problem. Hence, the considered problem is both geometrically and physically nonlinear. The considered highly non-linear problem is solved considering full geometric non-linearity by using incremental displacement-based finite element method in conjunction with Newton-Raphson iteration method. The beams considered in numerical examples are made of Austenitic Stainless Steel (316). The convergence studies are made. In this study, the difference between temperature dependent and independent physical properties are investigated in detail in post-buckling case. The relationships between deflections, thermal post-buckling configuration, critical buckling temperature, maximum stresses of the beams and temperature rising are illustrated in detail in post-buckling case.

• Steel and Composite Structures
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• v.7 no.1
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• pp.53-70
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• 2007

This paper presents a analysis of the problem of optimal design of the beams with two I-type cross section shapes. These types of beams are simply supported and subject to pure bending. The strength and stability conditions were formulated and analytically solved in the form of mathematical equations. Both global and selected types of local stability forms were taken into account. The optimization problem was defined as bicriteria. The cross section area of the beam is the first objective function, while the deflection of the beam is the second. The geometric parameters of cross section were selected as the design variables. The set of constraints includes global and local stability conditions, the strength condition, and technological and constructional requirements in the form of geometric relations. The optimization problem was formulated and solved with the help of the Pareto concept of optimality. During the numerical calculations a set of optimal compromise solutions was generated. The numerical procedures include discrete and continuous sets of the design variables. Results of numerical analysis are presented in the form of tables, cross section outlines and diagrams. Results are discussed at the end of the work. These results may be useful for designers in optimal designing of thin-walled beams, increasing information required in the decision-making procedure.

• Journal of the Korean Society of Clothing and Textiles
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• v.25 no.1
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• pp.162-172
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• 2001

Fashion is the social process concerned with the spread of a new product from its source to consumer. Fashion leadership may be associated the shopping-related behaviors, such as shopping motives, on-going information search, impulse buying behavior. In order to study the relationship between the fashion leadership and the shopping-related characteristics, Three research problems were set up for the study as follows: Research problem 1: To investigate the fashion leadership. Research problem 2: To analyze the relationship between the fashion leadership and the characteristics of shopping-related behavior. Research problem 3: To analyze the relationship between the fashion leadership and other fashion-related behaviors. After statistical analysis using the SPSSWIN, the following results was found. Fashion leadership approximates the normal distribution curve, and its structure consists of one dimension. Using the factor analysis, the two kinds of shopping motive was confirmed hedonic motive and cognitive motive. Fashion leadership was related to the hedonic shopping motive. Also there were positive associations between the fashion leadership on-going information search behavior, and the impulse buying behavior. And there was significant association between the fashion leadership and expense for clothes and spending time for shopping.

• Korean Journal of Child Studies
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• v.35 no.4
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• pp.79-101
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• 2014

The purpose of this study was validate the Preschool and Kindergarten Behavior Scale-2(PKBS-2) and develop the Korean version PKBS-2(K-PKBS-2) through the phases of concept and statistical review. For this purpose, this study conducted PKBS-2 for teachers with 1,119 young children in Jeonbuk province. During the factor structure review, according to the results of exploratory factor analysis, 30 items and 4 factors(social interaction, social cooperation, social compliance, and social independence) in social skills scale and 40 items and 4 sub-factors of 3 factors(internalizing behavior, externalizing behavior, and interpersonal emotional behavior) in problem behavior scale were extracted. In addition, confirmatory factor analysis, the model fits of social skills and problem behavior scales were higher than the original test and very high reliability and internal consistency were produced. During external factor review, convergent validity and discriminant validity were verified. After cultural specificity and cultural universality between PKBS-2 and K-PKBS-2 were discussed, K-PKBS-2 was presented as e scale which is very useful for the screening, prevention, and intervention program plan of challenging behavior behaviors in young children in Korea.

• Smart Structures and Systems
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• v.26 no.2
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• pp.213-226
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• 2020

In this manuscript, static and dynamic behaviors of geometrically imperfect carbon nanotubes (CNTs) subject to different types of end conditions are investigated. The Doublet Mechanics (DM) theory, which is length scale dependent theory, is used in the analysis. The Euler-Bernoulli kinematic and nonlinear mid-plane stretching effect are considered through analysis. The governing equation of imperfect CNTs is a sixth order nonlinear integro-partial-differential equation. The buckling problem is discretized via the differential-integral-quadrature method (DIQM) and then it is solved using Newton's method. The equation of linear vibration problem is discretized using DIQM and then solved as a linear eigenvalue problem to get natural frequencies and corresponding mode shapes. The DIQM results are compared with analytical ones available in the literature and excellent agreement is obtained. The numerical results are depicted to illustrate the influence of length scale parameter, imperfection amplitude and shear foundation constant on critical buckling load, post-buckling configuration and linear vibration behavior. The current model is effective in designing of NEMS, nano-sensor and nano-actuator manufactured by CNTs.

• Korean Journal of Adult Nursing
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• v.19 no.5
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• pp.56-69
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• 2007

Purpose: This study aimed to explore the discourses and the patterns of problem solving behaviors among the nurse managers. The focus of the study was the difficult situations in caring with patients and their families. Methods: Field study was performed at a for-profit hospital from March, 2004 to March, 2007. The participants of the study were 5 head nurses and 2 nurses in charge. The data were collected with iterative interviews and participant-observations. For the analysis of the data, taxonomy and critical discourse analyzing were applied. Results: The nurse mangers who showed wholistic patterns of behavior took the role of a broker among the client system, professional nursing system, medical system, and other allied health system. The nurse managers whose approach was profession-centered took the role of protector of nursing system. The nurse manager who practiced nurse-oriented pattern of behavior tried not to have harm against other members of health system. The experiences of nurse managers were effected from the discourses of patriarchal and market mechanism. Conclusion: The situation that provoke conflict between clients and nurses become more common with the changes to the health care system and to society. Nurse managers take the role of these conflict problems. The successful solving of conflict in a nursing care setting promotes the quality of care and satisfaction of clients. Programs for enhancing nurse's problem solving competency should anchored be in their practices.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.11a
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• pp.166-171
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• 2001

In order to improve the efficiency of the design process and the quality of the resulting design for the application-based exclusive rolling element bearings, this study propose design methodologies by using a genetic-based combinatorial optimization. By the presence of discrete variables such as the number of rolling element (standard component) and by the engineering point of views, the design problem of the rolling element bearing can be characterized by the combinatorial optimization problem as a fully discrete optimization. A genetic algorithm is used to efficiently find a set of the optimum discrete design values from the pre-defined variable sets. To effectively deal with the design constraints and the multi-objective problem, a ranking penalty method is suggested for constructing a fitness function in the genetic-based combinatorial optimization. To evaluate the proposed design method, a robust performance analyzer of ball bearing based on quasi-static analysis is developed and the computer program is applied to some design problems, 1) maximize fatigue life, 2) maximize stiffness, 3) maximize fatigue life and stiffness, of a angular contact ball bearing. Optimum design results are demonstrate the effectiveness of the design method suggested in this study. It believed that the proposed methodologies can be effectively applied to other multi-objective discrete optimization problems.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.3 no.3
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• pp.176-183
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• 1991

In this paper. boundary element method is applied to the analysis of nonlinear free surface wave. A particular concern is given to the treatment of the open boundaries at the in-flow boundary and out-flow boundary, which uses the mass-flux and energy-flux considering the continuity of fluid. By assuming the fluid to be inviscid and incompressible and the flow to be irrotational. the problem is formulated mathematically as a two-dimentional nonlinear problem in terms of a velocity potential. The equation(Laplace equation) and the boundary conditions are transformed into two boundary integral equations. Due to the nonlinearity of the problem. the incremental method is used for the numerical analysis. Numerical results obtained by the present boundary element method are compared with those obtained by the finite element method and also with experimental values.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.9A
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• pp.2383-2390
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• 1998

As network provides diverse functionalities recently, many rpotocol standards have become complex and many implementations have appeared. Such trends require us to test th econformance of implementations, called the conformance testing. Many researches have been performed on generating test sequence and on fualt masking base don T,U,D,W methods. At this jpoint, te new problem is suggeste dwhich is calle dthe completenes s criteria. The test sequences for the conformance testing have come up with this problem as well as fault masking. In this paper, we suggest the method of generating the preverified test sequence which can avoid the completeness criteria problem. The preverified test sequence is much more reliable than others by using the preverified edge. For the reliability of conformance testing, we define the immunity of the test sequence and provide the clue for the analysis of the test results using the immunity. The analysis of the results makes it possible for us to test the implementation again with more reliability. Also, the preverified test sequence is flexible so that it is combined with the fault-tolerant sequence for fault masking.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.17 no.4
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• pp.351-363
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• 2004

Equation of motion of non conservative system considering mass matrix, elastic stiffness matrix, load correction stiffness matrix by circulatory force's direction change and Winkler and Pasternak foundation stiffness matrix is derived. Also stability analysis due to the divergence and flutter loads is performed. And the influence of internal and external damping coefficient on flutter load is investigated applying the quadratic eigen problem solution. Additionally the influence of non-conservative force's direction parameter, internal and external damping and Winkler and Pasternak foundation on the critical load of Beck's and Leipholz's and Hauger's columns are investigated.