• Tribology and Lubricants
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• 제16권1호
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• pp.39-45
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• 2000

In this paper, the effects of shaft and bearing flexibilities are investigated for the accurate modeling of a shaft-bearing system supported by ball bearings. Generally, rolling bearings are modeled by simple rigid pin-joint in the mechanical design. However, they can no longer be modeled by ideal boundary conditions in the advanced applications because the rigid pin-joint model cannot satisfy the current trends of mechanical design decreasing mass and reducing volume. Consequently the flexible support model of ball bearing is investigated using the static analysis module developed by A .B. Jones and T. A. Harris. A simple two-bearing system, supported by two deep groove ball bearings and radially loaded on the shaft midway between the bearings, is utilized to validate the coupled model of shaft-bearing system. Numerical computations using the model indicate that the shaft span length, locating/floating bearing arrangements and applied bearing size are significant factors in determining the mechanical behaviors. The flexible support model of ball bearing can be escaped to over-estimate in the bearing fatigue life. The proposed simple design formulation obtained by numerical simulations can approximately predict a rate of bearing life reduction as a function of shaft span length/shaft diameter (L/d).

• 정보관리연구
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• 제36권4호
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• pp.175-198
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• 2005

최근 이메일 서비스의 보완 수단으로서 RSS(Really Simple Syndication)를 이용한 정보 서비스가 활성화되고 있다. 과학기술 분야의 정보는 매우 방대하고 다양하며, 정보의 발생주기 및 서비스 또한 복잡한 특성을 가지고 있다. 단일 정보를 제공하는 기관인 경우 RSS를 이용한 정보 서비스는 정보를 제공하는 하나의 채널을 확보하는 의미에서 구현 시 고려해야 할 요소가 많지 않지만, 다양하고 방대하며 전문적인 과학기술정보의 특성을 반영한 RSS 서비스는 보다 정교한 설계와 구현을 필요로 한다. 본 연구에서는 RSS와 다른 정보배급 프로토콜을 비교하고, 국내외 RSS 동향조사를 수행하였으며, 과학기술정보의 특성을 고려한 RSS 기반 과학기술정보배급 시스템(STI-RSS)의 구현을 고찰하고 이의 활용방안을 제시하고자 한다.

• 정보처리학회논문지D
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• 제9D권2호
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• pp.243-250
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• 2002

In order to properly interpret and process or operators in deductive databases including indefinite clauses, we propose to use Lasez′s Strong Model Semantics(LSMS) which is reasonably simple yet powerful enough to support both exclusive and inclusive interpretations. Conventional semantics either fail to support both interpretations or simply too complex. Therefore, in this paper we study advantages and difficulties of representing indefinite information, and as for the solution to difficulties, we show how LSMS can be used to support both inclusive or and exclusive or interpretations. We also investigate and analyze it′s properties and show how it semantically differs from others. We believe that LSMS is the only "reasonably simple" semantics that supports both inclusive and exclusive interpretations.

• Communications for Statistical Applications and Methods
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• 제29권2호
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• pp.193-202
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• 2022

Semi-supervised learning has gained significant attention in recent applications. In this article, we provide a selective overview of popular semi-supervised methods and then propose a simple but effective algorithm for semi-supervised classification using support vector machines (SVM), one of the most popular binary classifiers in a machine learning community. The idea is simple as follows. First, we apply the dimension reduction to the unlabeled observations and cluster them to assign labels on the reduced space. SVM is then employed to the combined set of labeled and unlabeled observations to construct a classification rule. The use of SVM enables us to extend it to the nonlinear counterpart via kernel trick. Our numerical experiments under various scenarios demonstrate that the proposed method is promising in semi-supervised classification.

• 동서간호학연구지
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• 제14권2호
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• pp.39-46
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• 2008

Purpose: The study was undertaken from June 1 to July 15, 2008 to assess the effect of social support on self-esteem and life satisfaction in elderly volunteers. Methods: Social support, self-esteem, and life satisfaction were determined using previously established and accepted methods. Data analyses included frequency, ANOVA, t-test, Pearson correlation coefficient, and simple regression. Results: Subjects' social support, self-esteem, and life satisfaction were closely related. The relationships of social support/self-esteem, social support/life satisfaction, and self-esteem/life satisfaction were significant. Social support accounted for 15% of self-esteem and 12% of life satisfaction. Conclusions: Social support is a very important factor influencing self-esteem and life satisfaction of the elderly. Social support, which sustains the mental health of the elderly, represents one of the best strategic nursing interventions.

• Journal of the Korean Wood Science and Technology
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• 제23권4호
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• pp.46-53
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• 1995

The anatomy of Korean diffuse-porous woods, 36 families, 75 genera, 145 species, 215 specimens was described and analyzed. Sixteen wood anatomical characters, habit and phenology factors were determined by simple correlation and principal component analysis. Strong positive correlations were found between vessel element length and fiber length, ray width and ray height, simple pits of fiber wall and paratracheal parenchyma distribution. The results of principal component analysis (PCA) disclose the primitive characteristics and the direction of xylem evolution of Korean diffuse-porous woods. The xylem evolution scenario for Korean dicotyledonous woods is considered to be developed in the direction of decreasing trends of vessel frequency, vessel element length, and length/diameter(L/D) ratio of vessel element but increasing trends of vessel diameter, fiber length/vessel element length(F/V) ratio, libriform wood fibers, simple perforation, and homogeneous ray composition. Increase of vessel diameter and decrease of vessel frequency seem to be related to the improvement of conductive efficiency, and increase of the vessel element length and occurrence of scalariform perforation in vessel element may be related to enhanced of conductive safety. Also the libriform wood fibers and ray features appear to have relationship with mechanical support and nutrient metabolism, respectively.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2005년도 추계 종합학술대회 논문집
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• pp.60-65
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• 2005

최근 RSS(Really Simple Syndication)를 응용한 서비스가 해외는 물론 국내에서도 각 분야에서 다양하고 활발하게 연구되고 있다. 과학기술분야 정보의 RSS서비스는 다양한 정보소스와 서비스 환경에 유연하게 적용할 수 있어야 하며 이러한 특성을 고려한 표준화된 시스템을 필요로 한다. 본 논문에서는 현재 국내외 RSS 서비스 사례조사를 통해 RSS 서비스 현황을 분석하고 설계에 반영하였으며, 이를 토대로 과학기술정보의 특성을 고려한 RSS기반 과학기술정보 배급 표준시스템의 구현 방안을 제시하였다.

• 대한전자공학회논문지TC
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• 제48권12호
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• pp.9-16
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• 2011

대부분의 이동성 관리 프로토콜 (즉, MIPv4/6, 이를 확장한 IETF 표준)은 글로벌한 끊김 없는 핸드오버를 지원하지 못한다. 기존의 이동성 관리 프로토콜은 현존하는 네트워크 인프라를 부분적으로 변경해야 하기 때문이다. 본 논문에서는 이기종 망간 글로벌 끊김 없는 핸드오버 방법인 간단한 이동성 관리 프로토콜 (Simple Mobility Management Protocol: SMMP)를 제안한다. 아이디어는 SMMP는 글로벌 사용자 및 서비스 이동성을 지원하기 위해 세션 개시 프로토콜 (Session Initiation Protocol: SIP)에서 한 별도의 위치 관리 기능을 이용하고, 추가적으로 IEEE 802.21 MIH 표준을 확장함으로써 양방향 터널링을 동적으로 생성함으로써 끊김 없는 IP 이동성을 지원하는 것이다. 이에 대한 상세한 SMMP 구조 및 기능을 설계하였다. 마지막으로, 성능 평가에서 NS-2를 이용한 시뮬레이션을 수행하였고, 이동성 관리 성능 평가의 지표인 핸드오버 지연시간, 패킷 손실 및 첨두 신호대 잡음비 (Peak Signal Noise Ratio: PSNR)에서 기존의 이동성 프로토콜인 MIPv6, HMIPv6에 비해 제안된 SMMP가 성능이 우수함을 보였다.

• 대한가정학회지
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• 제40권5호
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• pp.109-118
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• 2002

This study focused on the relationship among perceived social support from care teacher(institution staff), internal locus of control, and school adjustment of institutionalized children. This also examined the differences of perceived social support, internal thou of control, and school adjustment by gender and the duration in the institution. Participant were 119 fifth-and sixth-grade elementary school studens(58 boys, 61 girts). Perceived social support from care teacher, internal locus of control, and school adjustment were measured by self-reports of institutionalized children. The data were analyzed, in SPSS Win program, by Cronbach's α, T-test, Pearson Correlations, Simple Regression, Hierarchical Multiple Regression. As expected, results confirm that perceived social support was associated positively with internal locus of control and school adjustment. further, perceived social support also exerts indirect effects on school adjustment, mediated by internal locus of control. However, none of these variables differed by gender and the duration in the institution.

• 소음진동
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• 제10권1호
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• pp.153-159
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• 2000

This paper presents a new method for including the dynamic stiffness of the stationary parts in rotordynamic analysis. As a consequence of the support dynamics, critical speeds are varied and/or additional critical speeds are introduced. Therefore, dynamic effects of the support are often significant in high speed turbomachinery, but most of analysis has considered the support as a rigid body or a simple structure. The proposed method is based on the coupled characteristics of the driving point and transfer frequency response functions of the support system to model the equivalent spring-mass series in finite element analysis. To demonstrate the applicability of the simulation procedures provided, it is applied to the rotor model of the double suction centrifugal pump. Results of the suggested equivalent-support rotor model including coupled effects agree well with the entire pump model.