• Structural Engineering and Mechanics
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• 제32권5호
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• pp.609-620
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• 2009

In this paper the results of a series of experimental tests upon three-point bending specimens made of polystyrene and containing re-entrant corners are firstly described. Tests involved different notch angles, different notch depths and finally different sizes of the samples. All the specimens broke at the defect, as expected because of the material brittleness and, hence, the generalized stress intensity factor was expected to be the governing failure parameter. Recorded failure loads are then compared with the predictions provided by a fracture criterion recently introduced in the framework of Finite Fracture Mechanics: fracture is assumed to propagate by finite steps, whose length is determined by the contemporaneous fulfilment of energy balance and stress requirements. This fracture criterion allows us to achieve the expression of the generalized fracture toughness as a function of the tensile strength, the fracture toughness and the notch opening angle. Comparison between theoretical predictions and experimental data turns out to be more than satisfactory.

• Steel and Composite Structures
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• 제24권2호
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• pp.151-176
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• 2017

This paper deals with general equations of motion for free vibration analysis response of thick three-layer doubly curved sandwich panels (DCSP) under simply supported boundary conditions (BCs) using higher order shear deformation theory. In this model, the face sheets are orthotropic laminated composite that follow the first order shear deformation theory (FSDT) based on Rissners-Mindlin (RM) kinematics field. The core is made of orthotropic material and its in-plane transverse displacements are modeled using the third order of the Taylor's series extension. It provides the potentiality for considering both compressible and incompressible cores. To find these equations and boundary conditions, Hamilton's principle is used. Also, the effect of trapezoidal shape factor for cross-section of curved panel element ($1{\pm}z/R$) is considered. The natural frequency parameters of DCSP are obtained using Galerkin Method. Convergence studies are performed with the appropriate formulas in general form for three-layer sandwich plate, cylindrical and spherical shells (both deep and shallow). The influences of core stiffness, ratio of core to face sheets thickness and radii of curvatures are investigated. Finally, for the first time, an optimum range for the core to face sheet stiffness ratio by considering the existence of in-plane stress which significantly affects the natural frequencies of DCSP are presented.

• 천문학회보
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• 제39권2호
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• pp.78.1-78.1
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• 2014

An ionization front (IF) surrounding an H II region is a sharp interface through which a cold neutral gas makes transition to a warm ionized phase by absorbing UV photons from central massive stars. We investigate the structure and instability of a plane-parallel D-type IF threaded by magnetic fields parallel to the front. We find that magnetic fields increase the maximum propagation speed of the IFs, while reducing the expansion factor, defined as the density ratio of neutral to ionized phases. IFs become unstable to distortional perturbations due to gas expansion across the fronts, exactly analogous to the Darrieus-Landau instability of ablation fronts in terrestrial flames. The growth rate of the IF instability is proportional linearly to the perturbation wavenumber as well as the upstream flow speed. The IF instability is stabilized by gas compressibility and becomes completely quenched when the front is D-critical. The instability is also stabilized by magnetic pressure when the perturbations propagate in the direction perpendicular to the fields. When the perturbations propagate in the direction parallel to the fields, on the other hand, it is magnetic tension that reduces the growth rate, completely suppressing the instability when ${\beta}$ < 1.5, with ${\beta}$ denoting the square of the ratio of the sound speed to the Alfven speed in the pre-IF region. When the front experiences an acceleration, the IF instability cooperates with the Rayleigh-Taylor instability to make the front more unstable. We discuss potential effects of IF instability on the evolution and dynamics of IFs in the interstellar medium.

• Asian-Australasian Journal of Animal Sciences
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• 제14권11호
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• pp.1621-1627
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• 2001

Steers and heifers (N=490) were produced between 1991 and 1996 by reciprocal fiillsib backcross and $F_1$ crosses from Angus and Brahman to compare characteristics of carcass and palatability traits between Bos indicus and Bos taurus inheritance. Carcasses of 3/4Angus were heavier, fatter (p<0.05), more tender and higher in other palatability attributes (p<0.01) than those of 3/4Brahman. Reciprocal effects of parental cross breeds were found on some traits. Within 3/4Brahman inheritance group, Brahman sired progeny produced heavier and fatter carcasses with better palatability (p<0.05) than progeny with Brahman as a dam breed. Estimates of heritability were intermediate to high in most carcass and palatability traits. Genetic correlations of tenderness with marbling score (MARB), sarcomere length (SARC), fragmentation index (FRAG) and calpastatin activity (CALP) were moderate to high, suggesting potential use of the tenderness-influencing factors as indirect selection criteria to improve palatability attributes. MARB and SARC that were best predictors of tenderness explained 3.07 to 5.85% and 4.32 to 8.24% of variation in tenderness, respectively. However, there was no tenderness-influencing factor to dominantly explain large portion of variation in tenderness.

• 산업경영시스템학회지
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• 제22권51호
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• pp.11-19
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• 1999

This study intends to define $\ulcorner$personality$\lrcorner$ as $\ulcorner$Human-ware$\lrcorner$ based on $\ulcorner$Gene-ware$\lrcorner$ in business management. The sides of personality in management are important source of manifestation of ‘Synergy’, because the importance of personality, that is, $\ulcorner$attitude$\lrcorner$ in individuals is increasing compared with the traditional techniques, $\ulcorner$craft$\lrcorner$. In this work it is considered that Human-ware activates interchange in reciprocal relation between Gene-ware and Hard-ware and performs balancing, intermediating (catalyzing) functions in relative that things(Geneware $\leftrightarrow$ Humanware $\leftrightarrow$ Hardware). $\ulcorner$Gene-ware$\lrcorner$ represents factor and phenomena of life in evolutionary information as human instincts, system of Gene-duum(Gene＋Residuum(in phenomenology) ), Synchronization(in structuralism). In this view, this paper defines the concepts and effects of personality in management as the results of creative and stational functions of Human-ware. And this paper intends to identify the strata of psycho in human as three vertical aspects of $\ulcorner$Manifest$\lrcorner$, $\ulcorner$Latent$\lrcorner$, and $\ulcorner$Found$\lrcorner$, in this respects, function of Human-ware have analogy to that of Manifest in psychological behaviors. Finally, reviewing the Ford system based on Fordism and Taylor's system in Industrial Engineering, pursues the meaning and importance of personality, that is Humanware in management.

• 경영과정보연구
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• 제6권
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• pp.89-115
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• 2001

Recently, administrators of Korean university are struggling to survive against rapidly changing environment. But, the customer service of university organizations are generally recognized inferior to those of business service. Thus, the measuring of service quality is the beginning of works to improve customer service in university. SERVQUAL is known the most generalized scale to measure service quality. After SERVQUAL was published as a measure of perceived service quality by PZB(1985), several arguments have been made against its validity and the other measures have been suggested by Tears(1993), Cronin and Taylor(1992). Therefore, this paper reviews about SERVQUAL controversies. Also, this paper analyzed the dimensions of service quality and its relevant concepts. For this empirical study, 288 respondents drawn from university student in Pusan area are collected and 5 hypotheses are analyzed by using regression analysis. The results of empirical study are as follows. (1) three dimensions of service quality(specialty, reliability, tangiables) are perceived from factor analysis. (2) dimensions of service quality are related to the overall service quality and customer satisfaction, especially specialty is varified as the most important dimension. (3) customer satisfaction affects repurchase intention and word-of-mouth effect positively. In conclusion, however this study have a few limitations about sampling and questionnaire, offers some strategic directions for improving the service quality of university organizations.

• 한국환경교육학회지:환경교육
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• 제23권1호
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• pp.50-63
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• 2010

This study is a qualitative case study aiming at understanding and finding out influential factors and barriers when school teachers choose Environmental Education as their Creative Discretionary Activities. To do this, this study focuses on the process of two teachers' choices of the Creative Discretionary Activities in two other elementary schools. The results of this research are follows. Two teachers' choices are affected by several influential factors, divided into external factors and internal factors. External influential factors include culture of school and education, media, chief education officers, parents and school. Internal influential factors are teachers' value and philosophy of education, teachers' experiences, teachers' capacity. These influential factors' forces aren't the same with each other. These influential factors, are influenced by educational, social, national, local, and school level indicated by Taylor et al's (1974) classification criterion. Especially, however, Korea's particular educational environment focusing on university entrance examination strongly affects teachers' choice. School factors also has a big strong effect on teachers' choice. Among others internal actors are the most serious influential factor affecting on teachers' choice.

• 한국광학회지
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• 제14권6호
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• pp.583-587
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• 2003

본 논문에서는 피드포워드(feedforward) 방식의 2차 편광모드분산 보상에 있어서 보상 장치에서 발생시켜야 할 최적의 보상 벡터를 펄스 폭 증가율을 최소화함으로써 이론적으로 유도하였다. 최적의 2차 보상 벡터는 전송 선로의 편광모드분산 벡터의 단순한 Taylor전개식과는 달리, 편광모드분산 벡터와 출력 신호 편광의 주파수 평균들의 선형 조합으로 표현됨을 밝혔다. 최적의 2차 편광모드분산 보상에서의 펄스 폭 증가율을 해석적으로 계산하였으며, 계산 결과를 전산 모의 실험에 의한 결과와 비교하여 일치함을 확인하였다. 본 논문에서 유도한 최적의 2차 보상 벡터에 관한 공식은 피드포워드 방식의 2차 편광모드분산 보상에 반드시 필요한 정보를 제공한다.

• The Journal of Asian Finance, Economics and Business
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• 제8권5호
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• pp.1147-1154
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• 2021

The study aimed to investigate the impact of the microfinance program on loan borrowers' asset accumulation. In doing this, the study used descriptive and statistical methods to achieve the objectives. Primary data were collected from 192 respondents from Bangladesh using survey questionnaires. The data were analyzed using the multiple linear regression model. The result revealed that the majority of the borrowers said their assets such as farm, land, and livestock remained the same, which implies that microfinance borrowers still lag behind accumulating household assets. However, in the case of housing conditions and household appliances, there was a marginal increase. The regression result provides evidence that, among other factors, the amount of loan received from microfinance institutions and time duration with them is the most significant role-playing factor for borrower's sustainable well-being. The age and education level of borrowers are identified as positively related to asset accumulations, but not substantially so. Moreover, training provided by microfinance institutions is not effective and influential for microfinance borrowers' wealth accumulation, which is evidenced by the findings. This study's insights are worthwhile for any microfinance institution's decision-makers, development partners, and government to stress the shortcomings and accelerate the borrower's wealth status.

• Journal of applied mathematics & informatics
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• 제39권3_4호
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• pp.419-435
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• 2021

This paper deals with numerical treatment of singularly perturbed differential equations involving small delays. The highest order derivative in the equation is multiplied by a perturbation parameter 𝜀 taking arbitrary values in the interval (0, 1]. For small 𝜀, the problem involves a boundary layer of width O(𝜀), where the solution changes by a finite value, while its derivative grows unboundedly as 𝜀 tends to zero. The considered problem contains delay on the convection and reaction terms. The terms with the delays are approximated using Taylor series approximations resulting to asymptotically equivalent singularly perturbed BVPs. Inducing exponential fitting factor for the term containing the singular perturbation parameter and using central finite difference for the derivative terms, numerical scheme is developed. The stability and uniform convergence of difference schemes are studied. Using a priori estimates we show the convergence of the scheme in maximum norm. The scheme converges with second order of convergence for the case 𝜀 = O(N^-1) and for the case 𝜀 ≪ N^-1, the scheme converge uniformly with first order of convergence, where N is number of mesh intervals in the domain discretization. We compare the accuracy of the developed scheme with the results in the literature. It is found that the proposed scheme gives accurate result than the one in the literatures.