• Journal of KIISE:Information Networking
• /
• v.27 no.2
• /
• pp.149-159
• /
• 2000

In mobile computing environments, invalidation and propagation method based on broadcasting is used to transmit the information for cache maintenance of mobile hosts. Previous researches generally adopted invalidation method that easily adapts to the limited network bandwidth and the frequent disconnection. But the invalidation of frequently accessed data causes the contention on the wireless network with the increasing cache requests. Although the propagation method can reduce the cache requests, the high probability of broken message or loss of message is the main factor that degrades the system performance. To resolve these problems, we propose adaptive cache maintenance scheme that dynamically adjusts the broadcasting ratio of invalidation and propagation, according to the wireless network connection states. The proposed scheme broadcasts the propagation message in stable connection state, so it can reduce the cache requests and server response time. With the decreasing available network bandwidth by the frequent partial disconnection and disconnection, the proposed scheme dynamically increases the broadcasting ratio of the invalidation messages to minimize the broken message or the loss of message probability. Consequently, the proposed scheme resolves the problems which arise in the invalidation or propagation method in mobile computing environments.

• Journal of the Korea Convergence Society
• /
• v.9 no.9
• /
• pp.9-14
• /
• 2018

This study aims to investigate an importance of Author keyword with analysis the position of author keyword. An analysis was carried out on the position of author keyword. we examined an importance of Author keyword by using degree centrality, closeness centrality, betweenness centrality, eigenvector centrality. In the next stage, we performed analysis on correlation between network centrality measures and the position of keyword. As a result, degree centrality, closeness centrality, betweenness centrality, eigenvector centrality both has a high value in 4th author keyword order. eigenvector centrality was the comparatively effective method to separate of author keyword order method than other 3 centrality. Correlation analysis result shows that the network analysis value are increasing in order. This study has significance in that it was able to examine the author keyword behavior. Future research is needed to identify and supplement future situational factors, behavior, and psychology.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.20 no.3
• /
• pp.25-32
• /
• 2016

The pile-cap connection part which transfers foundation loads through pile body is critical element regarding flexural and shear force because the change of area, stress, and stiffness occurs in the this region suddenly. The purpose of this study is to investigate the structural behavior of pile-cap connection dependent on fabrication methods using conventional PHC pile and composite PHC pile. A series of test under cyclic lateral load was performed and the connection behavior was discussed. From the test results, it was found that the initial rotational stiffness of pile-cap connection was affected by the length of pile-head inserted in footing and the location of longitudinal reinforcing bars. The types of pile and location of longitudinal reinforcing bars governed the behavior of pile-cap connection regarding load-carrying capacity, ductility, and energy dissipation.

• Journal of Korean Society of societal Security
• /
• v.3 no.1
• /
• pp.33-42
• /
• 2010

This study predicts the stress history for truss bridge with local damages by using global-local model combination method. For this end, the global structure is modeled by 3D frame elements and the selected local details are modeled by shell elements. Then superposition principle enable the global-local model to be combined interactively. Because the frame model cannot consider the rigidity of gusset plate and the interation of structural members due to the complexity of stress distribution in truss connection. The section modification factors are proposed to calibrate the stiffness of global frame element. The global-local model combination is verified by comparing the numerical results with experimental data obtained from the proof loading test to the operating truss bridge. Furthermore, stress histrories of the truss bridge are generated in the consideration of the rigidity of truss connection with local damage by using the combination method.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.11 no.6
• /
• pp.914-919
• /
• 2000

A simple orthogonal mode transducer(OMT) for X-band has been proposed in this paper. This OMT is designed such that a polarized wave can be guided in a direction using several thin guiding posts, and the other orthogonally polarized wave can be guided in the other direction using other thin guiding posts. The OMT consists of a T-shaped waveguide section with guiding posts, two tapering waveguide arms, and has three flanges for connection with two adapters and an antenna. The optimum numbers and the optimum positions of the guiding posts were obtained numerically using the HFSS CAD tool. The isolation between two polarizations in a manufactured OMT is higher than 42.8 dB and the reflection from the OMT is lower than -17.5 dB at the frequency band of 9.5 GHz

• Journal of Advanced Navigation Technology
• /
• v.15 no.6
• /
• pp.1194-1211
• /
• 2011

The main research purpose of this paper is developed to Fusion Management System Model that is competition advantage and excellence airport for the airport authorities. Fusion Management System Model is developed to fuse and convert how is consist of creativity management and management quality system. Fusion management system structure is as follow. Firstly, part of foundation configured to philosophy and intention of CEO, company as like university and value-based creative corporate culture. Secondly, part of body is applied that is process by 6sigma, system by ISO9001. Thirdly, part of head is applied that is strategy and evaluation by Malcolm Baldrige National Quality Award of U.S.A. Also, system connected to synergy line that is creativity management, fusion & convergence and trust. Finally, this system has been researched to the practical perspective in order to realize for airport authorities.

• The Transactions of the Korea Information Processing Society
• /
• v.6 no.6
• /
• pp.1667-1677
• /
• 1999

An effective allocation of requested number of processors to newly incoming tasks in two-dimensional (2D) mesh interconnection networks is very important for achieving the desired high performance and resource utilization. It also needs to guarantee the complete recognition of the free submeshes based on contiguous and available processors with minimum overhead. An efficient task allocation algorithm for 2D meshes is presented in this paper. By employing a new approach for searching the one-dimensional array, the proposed algorithm can find the available submesh without the scanning of the entire 2D array unlike earlier designs. As a result, the new algorithm can significantly reduce the task allocation time. Comprehensive computer simulation shows that the average allocation time and waiting delay are much smaller than earlier irrespective of the size of meshes. The hardware overhead is comparable to other algorithms.

• Journal of Convergence Society for SMB
• /
• v.1 no.1
• /
• pp.67-73
• /
• 2011

Handover in high speed mobile communication service, in particulary mobile WiMAX is supported efficiency mobility to 120km/h speed. But, in order to accommodate number of user increment in a cell, wireless network is increment to microcell and picocell by allocate bandwidth and by decrease cell size. handover is occurrent and increment connection failure ratio In this result. IEEE 802.16 standard is support seamless connection through handover optimization scheme. But because authentication process is abbreviate, network weakness is exposure. In this paper, we propose handover scheme for support realtime service as VoIP, Picure communication, Streaming Data Service in order to support partially encryption method. In experiment, proposed scheme is proof which process time is increment 20% more than previous scheme.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.17 no.5
• /
• pp.1138-1149
• /
• 1993

A new mode synthesis method using Lagrange multipliers and substructure hybrid interface modes is presented. Substruture governing equations of motion are derived using Lagrange equations and the constraints of geometric compatibility between the substructures are treated with Lagrange multipliers. Fixed, free, and loaded interface modes can be employed for the modal bases of each substructure. In cases of the fixed and loaded interface modes, two successive modal transformation relations are used. Compared with the conventional mode synthesis methods, the suggested method does not construct the equations of motion of the coupled structure and the final characteristic equation becomes a polynomial. Only modal parameters of each substructure and geometric compatibility conditions are needed. The suggested method is applied to a simple lumped mass model and parametric study is performed.

• Journal of Korean Society of Steel Construction
• /
• v.26 no.3
• /
• pp.143-154
• /
• 2014

An improved method for evaluating effective buckling length of semi-rigid frame with inelastic behavior is newly proposed. Also, generalized exact tangential stiffness matrix with rotationally semi-rigid connections is adopted in previous studies. Therefore, the system buckling load of structure with inelastic behaviors can be exactly obtained by only one element per one straight member for inelastic problems. And the linearized elastic stiffness matrix and the geometric stiffness matrix of semi-rigid frame are utilized by taking into account 4th terms of taylor series from the exact tangent stiffness matrix. On the other hands, two inelastic analysis programs(M1, M2) are newly formulated. Where, M1 based on exact tangent stiffness matrix is programmed by iterative determinant search method and M2 is using linear algorithm with elastic and geometric matrices. Finally, in order to verify this present theory, various numerical examples are introduced and the effective buckling length of semi-rigid frames with inelastic materials are investigated.