• Kyungpook Mathematical Journal
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• v.63 no.1
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• pp.45-60
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• 2023

In this paper we suggest an enhanced Geraghty-type contractive mapping for examining the existence properties of classical nonlinear operators with or without prior degenerates. The nonlinear operators are proved to exist with the imposition of the Geraghty-type condition in a non-empty closed subset of complete metric spaces. To showcase some efficacies of the Geraghty-type condition, convergent rate and stability are deduced. The results are used to study some asymptotic properties of perturbed integral and hypergeometric operators. The results also extend and generalize some existing Geraghty-type conditions.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.528-533
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• 1988

Recently the needs for industrial robot system of high speed continuous path motion such as sealing application have been increasing. To apply to this kinds of work, dynamic analysis for Hyundai 8601 robot has been carried out by experiment. For the good design of high performance robot manipulator, accurate analysis of dynamic characteristics is important especially for current semi-closed loop control type industrial robots.

• Journal of applied mathematics & informatics
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• v.5 no.1
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• pp.223-233
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• 1998

This paper is concerned with the problem of existence of solutions to the initial value problem u'(t) = A(t, u(t)), u(a) = z in a probabilistic normed space where $A : [a,b)\;{\times}\;D->E$ is continuous, D is a closed subset of a probabilistic normed space E, and $z\;{\in}\;D$. With a dissipative type condition on A, we estabilish sufficient conditions for this initial value problem to have a solution.

• The Pure and Applied Mathematics
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• v.30 no.3
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• pp.237-248
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• 2023

The aim of this paper is to study the concept of s-topological d-algebras which is a d-algebra supplied with a certain type of topology that makes the binary operation defined on it d-topologically continuous. This concept is a generalization of the concept of topological d-algebra. We obtain several properties of s-topological d-algebras.

• Journal of Korean Society of Rural Planning
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• v.23 no.4
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• pp.99-110
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• 2017

This study is to analyze the spatial structure and POE of Jungja(pavilion) shelter for rural village regeneration. 14 Jungja shelter space at rural villages in Gyungbuk province, were investigated. An interview questionnaire was conducted for total 139 residents as POE. The use behavior and satisfaction for Jungja shelter space, were investigated. The statistical analysis were mean of satisfactions, reliability, factor analysis, and multiple regression analysis. The results and discussions can be objective data for rural village regeneration. In satisfaction level, 'Continuous use intention'(3.99), 'Well-suited approach'(3.87), and 'Helpful in resident living'(3.84) were shown to be high points of agreement in 5 point Likert type scale. But, the mean points were low as 2.01 in 'Surrounding landscape', 'Creation of green areas'(3.22), and 'Traffic safety'(3.22), respectively. Within use satisfaction, 5 factors were categorized, 'Use', 'Safety', 'Facility', 'Management' and 'Users'. By the result of multiple regression analysis, variables of 'Continuous use', 'Convenient location', and 'Image improvement', were shown to be main affecting variables to overall satisfaction. Furthermore, in spatial structure analysis, 4 types were categorized with the aspect of landform, roads, and location in village. The levels of satisfaction were shown to be high in village type of semi-open, road type of circular, and location type of center/back. Conclusively, these findings could be utilized as basic data and useful tool of space-structural satisfaction analytic method, and for each stage of planning/design and remodeling for rural village regeneration.

• Steel and Composite Structures
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• v.45 no.3
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• pp.349-367
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• 2022

In this research, an approach combining a semi-analytical method and an analytical method is presented to investigate the static and dynamic post-buckling behavior of the sandwich functionally graded (FG) porous cylindrical shells exposed to external pressure. The sandwich cylindrical shell considered is composed of a viscoelastic core and two FG porous (FGP) face layers. The viscoelastic core is made of Kelvin-Voigt-type material. The material properties of the FG porous face layer are considered continuous through each face thickness according to a porosity coefficient and a volume fraction index. Two types of sandwich FG porous viscoelastic cylindrical shells named Type A and Type B are considered in the research. Type A shell has the porosity evenly distributed across the thickness direction, and Type B has the porosity unevenly distributes across the thickness direction. The FG face layers are considered in two cases: outside metal surface, inside ceramic surface (OMS-ICS), and inside metal surface, outside ceramic surface (IMS-OCS). According to Donnell shell theory, von-Karman equation, and Galerkin's method, a discretized nonlinear governing equation is derived for analyzing the behavior of the shells. The explicit expressions for static and dynamic critical buckling loading are thus developed. To study the dynamic buckling of the shells, the governing equation is examined via a numerical approach implementing the fourth-order Runge-Kutta method. With a procedure presented by Budiansky-Roth, the critical load for dynamic post-buckling is obtained. The effects of various parameters, such as material and geometrical parameters, on the post-buckling behaviors are investigated.

• Korean Chemical Engineering Research
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• v.55 no.3
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• pp.341-352
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• 2017

Butyl acetate is produced from acetic acid and butanol via an esterification reaction in a reactive distillation column. Entrainer can be used for efficient removal of produced water from the reaction region, leading to significant improvement of the column performance. Batch reactive distillation has clear advantages over continuous one in terms of flexibility and adaptability in a small plant. We studied batch and semi-batch reactive distillation processes through process simulation and pilot-scale experiments. We investigated process configuration and type of entrainer for improvement of the column performance and suggested a novel cyclic operation strategy using the semi-batch reactive distillation column. The cyclic strategy was shown to give relatively high production rate and stable operation.

• Structural Engineering and Mechanics
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• v.55 no.4
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• pp.765-784
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• 2015

Connections are usually designed either as pinned usually associated with simple construction or rigid normally is associated with continuous construction. However, the actual behaviour falls in between these two extreme cases. The use of partial strength or semi-rigid connections has been encouraged by Euro-code 3 and studies on semi-continuous construction have shown substantial savings in steel weight of the overall construction. Composite connections are proposed in this paper as partial or full strength connections. Standardized connection tables are developed based on checking on all possible failure modes as suggested by "component method" for beam-to-column composite connection on major axis. Four experimental tests were carried out to validate the proposed standardised connection table. The test results showed good agreement between experimental and theoretical values with the ratio in the range between 1.06 to 1.50. All tested specimens of the composite connections showed ductile type of failure with the formation of cracks occurred on concrete slab at maximum load. No failure occurred on the Trapezoidal Web Profiled Steel Section as beam and on the British Section as column.

• Structural Engineering and Mechanics
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• v.74 no.1
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• pp.91-104
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• 2020

A mathematical analysis has been carried out for understanding the traversal attributes of torsional waves in a Voigt-type viscoelastic porous layer bounded with corrugated surfaces resting over a heterogeneous transversely isotropic gravitating semi-infinite medium. Both the media are assumed to be under the effect of initial stresses acting along horizontal directions. In the presumed geometry, continuous and periodic type of corrugation has been considered. The condensed form of dispersion relation has been obtained analytically with the aid of the Whittaker's function and suitable boundary conditions. The influence of viscoelasticity, porosity, initial stresses, heterogeneity, gravity, undulation and position parameters on the phase and damped velocities has been illustrated graphically. In addition, relative examination investigating the impact of corrugated and planar bounded surfaces on the dispersion and damping characteristics is one of the important highlights of this study.

• Journal of the Korean Mathematical Society
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• v.41 no.5
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• pp.821-864
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• 2004

Both parametric and parameter-free necessary and sufficient optimality conditions are established for a class of nondiffer-entiable nonconvex optimal control problems with generalized fractional objective functions, linear dynamics, and nonlinear inequality constraints on both the state and control variables. Based on these optimality results, ten Wolfe-type parametric and parameter-free duality models are formulated and weak, strong, and strict converse duality theorems are proved. These duality results contain, as special cases, similar results for minmax fractional optimal control problems involving square roots of positive semi definite quadratic forms, and for optimal control problems with fractional, discrete max, and conventional objective functions, which are particular cases of the main problem considered in this paper. The duality models presented here contain various extensions of a number of existing duality formulations for convex control problems, and subsume continuous-time generalizations of a great variety of similar dual problems investigated previously in the area of finite-dimensional nonlinear programming.