• Journal of Power System Engineering
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• v.18 no.5
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• pp.60-65
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• 2014

This research examined an immediate loading capable of providing a masticatory function and financial affordability while satisfying every requirement of a useful immediate loading. In this research, numerical value analysis was performed on couple-type posterior teeth implants developed by making up for the problems of extant implants. As a result of examining the effects of external impacts on extant implants and their deformation, relatively lager deformations separated from a molar were found concerning molar deformation implant with the maximum deformation level being approximately 1.657mm. In this research, the improved implant showed much improvement in terms of impact analysis in its deformation dispersion status after unloading the impulsive load from a punch. As for the case of hepf, about 1.657mm occurred but the improved model showed about 0.9217mm, exhibiting 55.6% advancement.

• Journal of Korean Society of Steel Construction
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• v.18 no.6
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• pp.707-716
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• 2006

The optimization of the direct design system of semi-rigid steel frames using advanced analysis and genetic algorithm was presented. Advanced analysis can predict the combined nonlinear effects of connection, geometry, and material on the behavior and strength of semi-rigid frames. Geometric nonlinearity was determined using stability functions. On the other hand, material nonlinearity was determined using the Column Research Council (CRC) tangent modulus and parabolic function. The Kishi-Chen power model was used to describe the nonlinear behavior of semi-rigid connections. The genetic algorithm was used as the optimization technique. The objective function was assumed as the weight of the steel frame, with the constraint functions accounting for load-carrying capacities, deflections, inter-story drifts and ductility requirement. Member sizes determined by the proposed method were compared with those derived using the conventional method.

• International Journal of Ocean System Engineering
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• v.1 no.4
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• pp.205-210
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• 2011

High data-rate underwater communications is demanded. This demand imposes stringent requirements on underwater communication equipment of phase-locked-loop (PLL). Phase noise in PLL is unwanted and unavoidable. In this paper, we investigate the PLL phase noise effect on high order QAM for underwater communication systems. The phase noise model using power spectral density is adopted for performance evaluation. The phase noise components considered in PLL are reference oscillator, voltage controlled oscillator (VCO), filter and divider. The filters in PLL noise are assumed to be second order active and passive low pass filters. Through simulation, we analyze the phase noise characteristics of the four components and then investigate the performance improvement factor of each component. Consequently, we derive specifications of VCO, phase detector, divider to meet performance requirement of high data-rate communication using QAM under phase noise influence.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.43 no.4 s.310
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• pp.1-10
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• 2006

This paper presents a development of a mobile sign language recognition system for daily communication of deaf people, who are sign dependent to access language, with hearing people. The system observes their sign by a cap-mounted camera and accelerometers equipped on wrists. To create a real application working in mobile environment, which is a harder recognition problem than lab environment due to illumination change and real-time requirement, a robust hand segmentation method is introduced and HMMs are adopted with a strong grammar. The result shows 99.07% word accuracy in continuous sign.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.1
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• pp.59-67
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• 2012

In this paper, we designed an inter-operation architecture of 10G G-PON(Gigabit passive optical network) network and NGN(Next generation network) architecture. And, we proposed mechanism of dynamic GEM(G-PON encapsulation mode) Port-ID allocation. This is able to solve a problem of 10G G-PON inter-operation. The mechanism of dynamic GEM Port-ID allocation has OMCI(ONT management control and interface) mapping table for IP address and port number. That architecture is able to support per flow QoS(Quality of service) as well as QoS of NGN requirement. So that can improve the resource efficiency of QoS than the existing G-PON architecture.

• Journal of the Korean housing association
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• v.26 no.5
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• pp.53-60
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• 2015

This study is aimed at identifying and evaluating the current operating model of elderly group homes in Korea, which were introduced with the amendment to the Welfare of the Aged Act in 2008, based on a survey of 25 managers of such homes. There are several key themes identified in the evaluation of their operation in terms of human resources, service, space and finance. The number of employees at the homes complied with the applicable law, with the majority having more employees than the minimum legal requirement for the care of residents. A wide variety of service programs were offered for residents. Typically located within detached houses purchased on the first floor, the homes varied in size from 73 square meters to 560 square meters, with each having a distinctly residence-like atmosphere. The greatest challenge such homes face was a shortage of financial resources. Many struggled to operate because they have no other source of revenue than payments from residents. Consequently, to help promote elderly group homes, there needs to be state-level support for the view that providing assistance for self-sufficient elders can save social costs in the long run by delaying their transition to a physical state requiring constant nursing.

• Journal of Mechanical Science and Technology
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• v.19 no.spc1
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• pp.272-282
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• 2005

A vehicle driving simulator is a virtual reality device which makes a man feel as if he drove an actual vehicle. Unlike actual vehicles, the simulator has limited kinematical workspace and bounded dynamic characteristics. So it is difficult to simulate dynamic motions of a multi-body vehicle model. In order to overcome these problems, a washout algorithm which controls the workspace of the simulator within the kinematical limitation is needed. However, a classical washout algorithm contains several problems such as generation of wrong sensation of motions by filters in tilt coordination, requirement of trial and error method in selecting the proper cut-off frequencies and difficulty in returning the simulator to its origin using only high pass filters. This paper proposes a washout algorithm with new tilt coordination method which gives more accurate sensations to drivers. To reduce the time in returning the simulator to its origin, an algorithm that applies selectively onset mode from high pass filters and return mode from error functions is proposed. As a result of this study, the results of the proposed algorithm are compared with the results of classical washout algorithm through the human perception models. Also, the performance of the suggested algorithm is evaluated by using human perception and sensibility of some drivers through experiments.

• Smart Structures and Systems
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• v.21 no.5
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• pp.611-621
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• 2018

Compared with the highway bridges, the relatively higher requirement on the safety and comfort of vehicle makes the high-speed railway (HSR) bridges need to present enhanced dynamic performance. To this end, installing a health monitor system (HMS) on selected key HSR bridges has been widely applied. Typically, the HSR takes fully enclosed operation model and its skylight time is very short, which means that it is not easy to operate the acquisition devices and download data on site. However, current HMS usually involves manual operations, which makes it inconvenient to be used for the HSR. Hence, a HMS named DASP-MTS (Data Acquisition and Signal Processing - Monitoring Test System) that integrates the internet, cloud computing (CC) and virtual instrument (VI) techniques, is developed in this study. DASP-MTS can realize data acquisition and transmission automatically. Furthermore, the acquired data can be timely shared with experts from various locations to deal with the unexpected events. The system works in a Browser/Server frame so that users at any places can obtain real-time data and assess the health situation without installing any software. The developed integrated HMS has been applied to the Xijiang high-speed railway arch bridge. Preliminary analysis results are presented to demonstrate the efficacy of the DASP-MTS as applied to the HSR bridges. This study will provide a reference to design the HMS for other similar bridges.

• Journal of Korea Multimedia Society
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• v.5 no.5
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• pp.552-561
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• 2002

In this paper, a new watermarking algorithm for STL files which contains 3D geometric information as triangular facets is proposed. STL files are widely used in rapid prototyping industry as a standard interchange format. The proposed algorithm inserts multi-bit watermark information into the surface normal vector and vertex description area of STL file without distorting the original 3D geometric information. According to the watermark bits, the position of normal vector and the direction of vertex sequence are modulated. The proposed algorithm is robust to the attack of changing the order of the triangular meshes. In addition, the invisibility requirement is also satisfied. Experiment results show that the proposed algorithm can encode and decode watermark bits into the various STL files without any distortion of 3D shape.

• Journal of Korea Multimedia Society
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• v.14 no.8
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• pp.1029-1040
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• 2011

Electronic identity (e-ID) card based on smartcard is a representative identity credential for on-line and off-line personal identification. The e-ID card can store the personal identity information securely, so that the information can be accessed fast, automated identity verification and used to determine the cardholder's authorization to access protected resources. Due to such features of an e-ID card, the number of government organizations and corporate enterprises that consider using e-ID card for identity management is increasing. In this paper, we present an authentication framework for access control system using e-ID cards by discussing the threat environment and security requirement against e-ID card. Specifically, to accomplish our purpose, we consider the Personal Identity Verification system as our target model.