• Structural Engineering and Mechanics
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• v.73 no.1
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• pp.1-16
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• 2020

Finite elements based on the partition of unity (PU) approximation have powerful capabilities for p-adaptivity and solutions with high smoothness without remeshing of the domain. Recently, the PU approximation was successfully applied to the three-node shell finite element, properly eliminating transverse shear locking and showing excellent convergence properties and solution accuracy. However, the enrichment with the PU approximation results in a significant increase in the number of degrees of freedom; therefore, it requires greater computational cost, thus making it less suitable for practical engineering. To circumvent this disadvantage, we propose a new strategy to decrease the total number of degrees of freedom in the existing PU-based shell element, without loss of optimal convergence and accuracy. To alleviate the locking phenomenon, we use the method of mixed interpolation of tensorial components and perform convergence studies to show the accuracy and capability of the proposed shell element. The excellent performances of the new shell elements are illustrated in three benchmark problems.

• Journal of Korean Society of Steel Construction
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• v.16 no.3 s.70
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• pp.295-303
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• 2004

In this paper, an improved four-node Reissner-Mindlin plate-bending element with enhanced assumed strain field is presented for the analysis of isotropic and laminated composite plates. To avoid the shear locking and spurious zero energy modes, the transverse shear behavior is improved by the addition of a new enhanced shear strain based on the incompatible displacement mode approach and bubble function. The "standard" enhanced strain fields (Andelfinger and Ramm, 1993) are also employed to improve the in-plane behaviors of the plate elements. The four-node quadrilateral element derived using the first-order shear deformation theory is designated as "14EASP". Several applications are investigated to assess the features and the performances of the proposed element. The results are compared with other finite element solutions and analytical solutions. Numerical examples show that the element is stable, invariant, passes the patch test, and yields good results especially in highly distorted regimes.

• Journal of Power System Engineering
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• v.16 no.2
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• pp.11-16
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• 2012

In this paper, the authors formulate the sensitivity analysis algorithm for the natural frequency of a torsional shafting by expanding the transfer stiffness coefficient method. The basic concept of the present algorithm is based on the transfer of sensitivity stiffness coefficient, which is the derivative of stiffness coefficient with respect to design parameter, at every node from the first node to the last node in analytical model. The effectiveness of the present algorithm is confirmed by comparing the results of the sensitivity analysis and those of the reanalysis for the natural frequencies of a torsional shafting with a constant cross section. In numerical calculation, the design parameter is the diameter of the shaft element of the torsional shafting.

• Earthquakes and Structures
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• v.16 no.1
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• pp.55-67
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• 2019

The finite solutions of deflection and the corresponding in-plane stress values of the graded sandwich shallow shell structure are computed in this research article via a higher-order polynomial shear deformation kinematics. The shell structural equilibrium equation is derived using the variational principle in association with a nine noded isoprametric element (nine degrees of freedom per node). The deflection values are computed via an own customized MATLAB code including the current formulation. The stability of the current finite element solutions including their accuracies have been demonstrated by solving different kind of numerical examples. Additionally, a few numerical experimentations have been conducted to show the influence of different design input parameters (geometrical and material) on the flexural strength of the graded sandwich shell panel including the geometrical configurations.

• Magazine of the Korea Concrete Institute
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• v.8 no.2
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• pp.119-127
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• 1996

Objection of this study is to present the three-dimensional material nonlinear analysis of reinforced concrete. A concrete is idealized with three-dimensional 16-node solid element including triaxial nonlinear stress-strain behavior, cracking, crushing and strain softening: a steel with three-dimensional 3 node truss element including elastic-plastic behavior with strain hardening. The cracked shear retention factor is introduced to estimate the effective shear modulus con sidering aggregate interlock after c:racking and a modified newton method is used to obtain a nu merical solution. Numerical results in a gauss point is displayed graphically. Numerical examples of Krahl's reinforced concrete beam and Hedgreds shell are selected to compare with the experimental and numerical results.

• International Journal of Highway Engineering
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• v.16 no.2
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• pp.25-34
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• 2014

PURPOSES : This paper numerically evaluates the contribution of transverse steel to the structural behavior of continuously reinforced concrete pavements to understand the role of transverse steel. METHODS : Two-lane continuously reinforced concrete pavements with and without transverse steel were analyzed through finite element analysis with the aid of commercial finite element analysis program DIANA; the difference in their structural behavior such as deflection, joint opening, and stress distribution was then evaluated. Twenty-node brick elements and three-node beam elements were used to model concrete and steel, respectively. Sub-layers were modeled with horizontal and vertical tensionless spring elements. The interactions between steel and surrounding concrete were considered by connecting their nodes with three orthogonal spring elements. Both wheel loading and environmental loading in addition to self-weight were considered. RESULTS : The use of transverse steel in continuously reinforced concrete pavements does not have significant effects on the structural behavior. The surface deflections change very little with the use of transverse steel. The joint opening decreases when transverse steel is used but the reduction is quite small. The transverse concrete stress, rather, increases when transverse steel is used due to the restraint exerted by the steel but the increase is quite small as well. CONCLUSIONS : The main role of transverse steel in continuously reinforced concrete pavements is supporting longitudinal steel and/or controlling unexpected longitudinal cracks rather than enhancing the structural capacity.

• Convergence Security Journal
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• v.13 no.6
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• pp.11-16
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• 2013

Mobile node must move optionally and perform the router and the host functions at the same time. These characteristics of nodes have become a potential threatening element of a variety of attacks. In particular, a black hole which malicious node causes packet loss among them is one of the most important issues. In this paper, we propose distributed detection technique using monitoring tables in all node and cooperative detection technique based cluster for an efficient detection of black hole attack. The proposed technique performs by dividing into local detection and cooperative detection process which is composed of process of step 4 in order to improve the accuracy of the attack detection. Cluster head uses a black hole list to cooperative detection. The performance of the proposed technique was evaluated using ns-2 simulator and its excellent performance could be confirmed in the experiment result.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.6 s.111
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• pp.609-618
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• 2006

This study is undertaken for the vibration analysis of tapered thick plate with concentrated mass on elastic foundation. The boundary condition of the plate is analyzed with the 4-sides simply supported and 4-fixed basis. This study find out the frequency following the change in size for each foundational variable on Pasternak foundation, one of the two-parameter elastic foundation parameter that considered the shear layer to the Winkler foundation parameter. The concentrated mass is applied with the consideration of mass of the entire plate, and the change of frequency is studies on each location with the consideration of reacting for the three locations for concentrated mass. And, in order to find out the change of frequency on the thickness of the plate, it considered tapered ratio that linearly changes depending on the length of the plate with the thickness of the plate in x-direction, and the tapered ratio has changes with 4 types ($\alpha$=0.25, 0, 5, 0.75, and 1.0). For the interpretation, the program using finite element method (F.E.M.) is used and the element coordination is used the 8-node serendipity element. Therefore, the purpose of this study is to find out the characteristics of plate vibration under the mechanica vibration or external vibration factor to facilitate as the basic data of the design to secure the stability.

• Journal of Communications and Networks
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• v.16 no.6
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• pp.645-655
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• 2014

Latency, an identified element of Internet protocol (IP) mobility protocol execution, can reduce handover performance in mobile networks. Although the performance can be improved by applying an effective network-based IP mobility scheme in place of the traditional host-based alternatives, the existing inter-domain extensions of network-based IP mobility continue to suffer from an extended handover latency. This paper proposes a new inter-domain network-based IP mobility scheme based on node movement prediction. The proposed scheme accelerates the handover by preparing the future domain of the mobile node in a proactive manner. Analytical and simulation-based evaluations confirm improved performance of the proposed scheme in terms of handover latency and packet loss compared with existing schemes.

• Korean Institute of Interior Design Journal
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• v.16 no.6
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• pp.144-151
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• 2007

The idea of shopping is changed from a purchase of merchandise to an experience of pleasure. This study is a space composition analysis for the introduction of theme in multi-plex shopping center design to reflect variable consumer trend and company marketing strategy, The study progressed through theoretical consideration and substance analysis about the shopping centers which had been designed by Jerd Partnership In Japan since 2000. The following is result. The path is a sole main street that is made of curve form, parallel and vertical circulating rout and movement of human being. It leads continuity. The node and landmarks have a circular court with typifier as powerful center, character of transition space and event for experience. It makes locational quality. The districts are composed of retail shops, restaurants and culture facilities and the edge is represented by closed vertical wall and parapet. It induces a domain. The characteristic of Jerde shopping center is an experience of theme environment through the path as betweenness with a story based on a main theme. It is mostly related nature or exotic element and is obviously represented at path and node. The node takes a round shape and bring about event as a court. The application of theme to the shopping center by Jerde has a significant meaning for place marketing.