• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.32 no.8B
• /
• pp.492-501
• /
• 2007

UMTS-WLAN interworking approach can make the best use of the advantages of both networks by eliminating the stand-alone defects of the two services. For the interworking mechanisms of WLANs and UMTS networks, two major solutions have been proposed, namely loose coupling and tight coupling. The loose coupling approach provides separate data paths for WLAN and UMTS. On the other hand, the tight coupling provides a full integration of the WLAN network and the UMTS core network. The loose coupling has been preferred due to the simplicity and less reconfiguration requirement. However, loose coupling is worse in seamless mobility, QoS provision, and network security. In order to lessen the problems involved in the UMTS-WLAN interworking approaches, we propose a new interworking network architecture and a fast vertical handover scheme by employing Mobility Anchor(MA) for interworking between the two different networks. MA can enable authentication and session initialization before L2 handover of the mobile terminal, so that the seamless and fast vertical handover become possible. Thru analysis and numerical experiments, we proved that the proposed scheme has been validated.

• Journal of KIISE:Computing Practices and Letters
• /
• v.7 no.3
• /
• pp.260-272
• /
• 2001

In this paper, we have designed a region-based image retrieval system, FRIP(Finding Region In the Pictures). This system includes a robust image segmentation scheme using color and texture direction and retrieval scheme based on features of each region. For image segmentation, by using a circular filter, we can protect the boundary of round object and merge stripes or spots of objects into body region. It also combines scaled and shifted color coordinate and texture direction. After image segmentation, in order to improve the storage management effectively and reduce the computation time, we extract compact features from each region and store as index. For user interface, by the user specified constraints such as color-care / don't care. scale-care / dont care, shape-care / dont care and location-care / dont care, the overal/ matching score is estimated and the top Ie nearest images are reported in the ascending order of the final score.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.17 no.3
• /
• pp.158-165
• /
• 2005

In order to analyze incompressible two-phase flow, Level Set method was applied on pseudo-compressibility formulation. Level Set function is defined as a signed distance function from the phase interface, and gives the information of the each phase location and the geometric data to the flow. In this study, Level Set function transport equation was coupled with flow conservation equations, and owing to pseudo-compressibility technique we could solve the resultant vector equation iteratively. Two-phase flow analysis code was developed on general curvilinear coordinate, and numerical tests of bubble dynamics and surging wave problems demonstrate its capability successfully.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.15 no.4
• /
• pp.273-280
• /
• 2012

The numerical simulation using the Lattice Boltzmann Method in the field of computational fluid dynamics becomes wider in the engineering applications because of its simplicity of update rules compared to the conventional Navier-Stokes solvers. Here, a two-dimensional D2Q9 LB model is numerically tested with a few new computational treatment on the free surface. The single relaxation time is applied under the gravitational field where applied only in the higher density fluid because of its big density difference. At the free surface, the reconstruction techniques in combination with boundary conditions is adopted in order to get some distribution function coming into the fluid site from the air one, and surface tension, early stable test for the gravitional field is considered in it. With the implementation of the gravitational profile, conserving the overall mass and grid dependency are observed during the calculations and freesurface advance track is well captured with an experiment.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.20 no.1
• /
• pp.19-28
• /
• 2007

Discrete topology optimization processes of structures start from an initial design domain which is described by the topology of constant material densities. During optimization procedures, the structural topology changes in order to satisfy optimization problems in the fixed design domain, and finally, the optimization produces material density distributions with optimal topology. An introduction of initial holes in a design domain presented by Eschenauer et at. has been utilized in order to improve the optimization convergence of boundary-based shape optimization methods by generating finite changes of design variables. This means that an optimal topology depends on an initial topology with respect to topology optimization problems. In this study, it is investigated that various optimal topologies can be yielded under constraints of usable material, when partial solid phases are deposited in an initial design domain and thus initial topology is finitely changed. As a numerical application, structural topology optimization of a simple MBB-Beam is carried out, applying partial circular solid phases with varying sizes to an initial design domain.

• Journal of the Korean association of regional geographers
• /
• v.22 no.3
• /
• pp.714-729
• /
• 2016

National citizenship has been empathized by nation-state since modern times. But with recent wave of globalization, the force of national citizenship is gradually reducing. Globalization requires citizens of global citizenship needed in the global village on the one hand, and of cultural citizenship suited in multicultural society on the other hand. The trend shows that the geographical focus of citizenship is shifted or expanded from the political domain to the social and cultural domain. Moreover, with concerns of personal everyday life citizenship is extended from standard personality by Western view to inclusion and exclusion in micro everyday space, non-Western view based on social difference of gender, class, ethnicity etc. New spaces of citizenship, cultural citizenship and everyday citizenship which empathizes personal right and difference is emerging instead of national citizenship based on personal allegiance and duty of the state. This means that the state has not only a task of establishment of common national citizenship, but also a challenge to recognize of diversity of citizens.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.20 no.7
• /
• pp.1389-1397
• /
• 2016

This study was to evaluate opportunities for the commercialization of smart insole. smart technology is evolving to Insole. Pressure-sensitive sensor or an acceleration sensor is applied to create a balance of the feet and body, is also evolving for entertainment (sports, entertainment, etc.) and health care. Moreover, smart insole can fix an incorrect walking habit by sending a weight value measured by the sensor on a smartphone and during the movement, smart insole helps to correct body balance by measuring the center of gravity moving condition. However, smart tendency of the insole has yet to create a clear boundary in the entertainment and healthcare markets. This is because the fitness band, smart socks, smart shoes can also replace the benefits of a smart insole. Interestingly, the business opportunities are appearing more frequently in health care solution service of electrocardiogram, body temperature, blood pressure, etc., rather than smart devices.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.38 no.4
• /
• pp.527-535
• /
• 2018

Agricultural activities of western Jeju island has suffered from saltwater intrusion seasonally. Objectives of this study are to prove the occurrence of saltwater intrusion in the coastal aquifer and to consider a management plan using MODFLOW-family code SEAWAT model. Model results show that the saltwater-freshwater interface intrudes inland only a few meters and that upconing phenomenon is rather the cause of the severe disaster of the agricultural water contamination. This study selected Gosan area as a representative site to estimate optimal groundwater development regulation against upconing by seasonal pumping for agriculture. The suggested optimal groundwater development estimation method considers the groundwater levels of representative monitoring wells for regulatory alarms.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.30 no.3
• /
• pp.448-452
• /
• 2003

Ameloblastic fibro-odontoma is a rare benign odontogenic tumor that mainly occurs at mandibular molar area. Radiography usually shows a well-defined radiolucent area containing various amounts of radiopaque material of irregular size and form. In histiologic aspect, Ameloblastic fibro-odontoma composed of connective tissue characteristic of an ameloblastic fibroma and calcined tissue identifying the tumor as a complex odontoma. Thirteen years two months aged boy of this case visited with chief complaint of delayed eruption of mandibular left canine. After enucleation of lesion, biopsy was done and diagnosed by ameloblastic fibro-odontoma. In continous follow-up check, canine erupted normally after operation.

• Journal of Korean Association for Spatial Structures
• /
• v.11 no.1
• /
• pp.47-56
• /
• 2011

In general, shear walls are employed as lateral resistance system. Most of shear wall structures require openings in shear walls and thus shear walls are linked by floor slabs or coupling beams resulting in the coupled shear wall structures. In this study, an LRB (lead rubber bearing) was introduced in the middle of the coupling beam of the coupled shear wall structures and the wind-induced response reduction effect of this system was investigated. In order to evaluate the control performance of the proposed method, 20- and 30-story building structures were used as example structures and boundary nonlinear time history analyses have been performed using artificial wind excitation. Japanese vibration evaluation criteria was employed to evaluate whether the proposed system could improve the serviceability of the tall coupled shear wall structures under wind excitation. Based on analytical results, it has been shown that the proposed method that connects shear walls with LRBs can improve the wind-induced response control effect.