• 동력기계공학회지
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• 제18권5호
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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.

• 한국강구조학회 논문집
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• 제18권6호
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• pp.707-716
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• 2006

본 논문에서는 고등해석과 유전자 알고리즘을 이용한 반강접 강뼈대 구조물의 직접설계시스템의 최적화를 수행하였다. 고등해석은 접합부의 비선형, 기하학적 비선형 및 재료적 비선형을 고려한다. 기하학적 비선형은 안정함수를 사용하여 고려하였으며, 재료적 비선형은 CRC 접선 탄성계수와 포물선 함수를 사용함으로서 고려하였다. 접합부의 비선형은 Kishi와 Chen이 제안한 3가지 매개변수를 가지는 파워모델을 사용하여 고려하였다. 최적화 기법으로는 유전자 알고리즘을 사용하였다. 목적함수는 구조물의 중량을 사용하였으며, 제약조건식은 구조시스템의 하중-저항능력, 처짐, 층간 수평변위 및 연성요구 조건을 고려하였다. 제안된 방법에 의한 설계결과를 기존의 방법들과 비교하였다.

• International Journal of Ocean System Engineering
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• 제1권4호
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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.

• 전자공학회논문지SC
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• 제43권4호
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• pp.1-10
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• 2006

본 논문에서는 수화를 의사소통 수단으로 사용하는 청각 장애인이 일반인과 일상 대화를 할 수 있도록 도와주는 모바일 수화 인식 시스템을 다룬다. 개발된 시스템은 모자에 부착된 카메라와 손목에 착용한 가속도 센서를 통해 사용자의 수화 동작을 관찰하는데, 모바일 환경에서 실제 적용할 수 있도록 조명 변화에 둔감하고 실시간 처리가 가능하도록 개발하였다. 이를 위해 조명 변화에 강인한 손 영역 분할 방법을 제안하고 추출된 손 영역 정보를 히든 마르코프 모델의 입력으로 사용하여 연속적인 수화에 대해 99.07%의 단어 정확도를 얻었다.

• 대한전자공학회논문지TC
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• 제49권1호
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• pp.59-67
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• 2012

본 논문은 10G G-PON(Gigabit passive optical network) 네트워크와 NGN(Next generation network) 연동 구조를 설계하고, 10G G-PON 연동 시 문제점 해결을 위한 동적 GEM(G-PON encapsulation mode) Port-ID 할당 방법을 제안했다. 동적 GEM Port-ID 할당 방법은 OMCI(ONT management control and interface) 구조 설계를 통해 IP 주소와 포트 번호를 혼합한 형태의 맵핑 구조를 갖는다. 이는 NGN이 요구하는 클래스 기반 QoS(Quality of service) 뿐만 아니라 트래픽 단위의 QoS 지원까지 가능한 구조로서, 기존 G-PON 네트워크를 NGN에 그대로 적용시킨 구조 보다 QoS 지원에 있어 30% 이상 성능을 향상 시킨다.

• 한국주거학회논문집
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• 제26권5호
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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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• 제19권spc1호
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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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• 제21권5호
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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.

• 한국멀티미디어학회논문지
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• 제5권5호
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• pp.552-561
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• 2002

본 논문은 쾌속조형(rapid prototyping) 시스템에서 사용되며 3D 기하학적 형상을 가지는 STL 파일에 워터마크를 삽입하고 추출하는 방법에 관한 연구이다. 제안된 알고리즘은 3D 형상의 왜곡이 없도록 하기위해, 패싯의 법선 영역과 꼭지점 영역에 워터마크를 삽입한다. 워터마크 비트들은 법선의 위치와 꼭지점의 순서 정보를 이용하여 삽입된다 제안된 알고리즘은 패싯의 저장 순서에 대한 종속성이 없으며, 워터마크의 비가시성 (invisibility)을 충족한다. 제안된 알고리즘으로 3D 기하학적 형상에 워터마크를 삽입하고 추출하는 실험 결과들은 STL로 표현된 3D원형상에 영향을 주지 않고 워터마크의 삽입과 추출이 가능함을 보여준다.

• 한국멀티미디어학회논문지
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• 제14권8호
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• pp.1029-1040
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• 2011

스마트카드 기반의 전자신분증은 오프라인과 온라인 신분확인을 위한 대표적인 개인 신분확인 수단으로, IC칩에 카드소유자의 신분확인 정보와 암호기법이나 전자인증서 관리를 위한 암호화 모듈을 포함하게 된다. 개인 식별정보에 대한 빠른 접근성과 신뢰성 및 보안성으로 인해 주요자산에 대한 접근통제를 위해 전자신분증을 도입하려는 공공기관이나 기업들이 증가하고 있다. 본 논문에서는 전자신분증을 이용한 접근통제에서 개인 신분확인을 위한 인증시스템의 구현방안에 대해 제안하고, 효과적인 인증시스템의 운영을 위한 기능적 요구사항들에 대해 논의한다. 이를 위해 본 논문에서는 Personal Identity Verification 시스템 모델을 대상으로 하여 연구하였다.