• 한국정밀공학회지
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• 제14권2호
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• pp.92-101
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• 1997

In this paper, modeling methods for 2D joints are proposed. Earlier methods for modeling 2D joints that use geometric relationships may not consider irregularities or dynamic effects of joints. In any case, it is important to consider irregularities or dynamic effects. To consider those, methods that use dynamic contacts are proposed. With the method, 2D joints that have irregularities or dynamic effects amy be model- ed and analyzed. 2D joints that are developed are revolute, translational, gear and point-follower joint.

• 대한기계학회논문집A
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• 제28권5호
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• pp.511-516
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• 2004

The dynamic behavior of an automatic ball balancer (ABB) is studied considering the effects of gravity and angular velocity profiles. In this study, a physical model for an ABB installed on the Jeffcott rotor is adopted in order to investigate the effects of gravity and angular acceleration. The equations of motion for the rotor with ABB are derived by using Lagrange's equation. Based on derived equations, dynamic responses for the rotor are computed by using the generalized-o method. From the computed responses, the effects of gravity and angular velocity profiles on the dynamic behavior are investigated. It is found that the balancing of the rotor with ABB can be achieved regardless of gravity. It Is also shown that a smooth velocity profile yields relatively smaller vibration amplitude than a non-smooth velocity profile.

• 산업경영시스템학회지
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• 제41권3호
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• pp.30-40
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• 2018

The purpose of this study is to examine the effect of project-based organizational resources on the business performance in the resource-based view (RBV) and dynamic capability one and analyze their relationship through an integrated model. The RBV argues that firms get competitive advantages when they have VRIN characterized resources but dynamic capability view argues that RBV has its limitation under volatility so it enables them to obtain competitive advantages in ever changing environments. This study analyzes data collected from 270 survey questionnaires on the project management related staff at the project-based organization among major companies in Korea. The result demonstrates that two project organizational resources on strategic and executional management with VRIN characteristics are found to bring positive effects on the organizational dynamic capabilities and also the dynamic capabilities such as integration & reconfiguration, organizational learning are verified to bring meaningful positive effects on the business performance. On the other hand, unlike previous studies, ambidexterity has quite a weak effect on the business performance. Therefore, we expect that the resources of the project-based organization with VRIN lead to strengthen the firm's business performance through organizational dynamic capabilities and produce high performance through the integrated model of RBV and dynamic capability one. The study has academic meanings that widely confirm the effects and characteristics of main elements of VRIN project organizational resources on the business performance of competitive advantage through the dynamic capabilities of the organization by the regression on the precedent studies regarding the project management resources and their relationship with the VRIO characteristics. The practical implication is that it is preferentially necessary for the organization to obtain VRIN resources and organizational dynamic capabilities, especially organizational learning to have sustainable competitive advantages.

• 소음진동
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• 제3권1호
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• pp.57-63
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• 1993

The dynamic response of stiffened rectangular plate subjected to a concentrated force or mass moving at constant speed is analyzed by using finite- element method. Stiffened plates are modelled as an assembly of isotropic thin plate elements and equivalent Euler beam ones, in which the beam elements represent the stiffener effects concentrated at the attached lines of stiffeners to the plates. The Newmark's time integration method is used to obtain the dynamic response of stiffened plates. Numerical examples are given to verify the validity of the presented method and also to investigate the effects of speed and moving mass on the dynamic characteristics of stiffened plates.

• 품질경영학회지
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• 제19권2호
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• pp.1-16
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• 1991

Recently, Cook and Weisberg(l989) presented dynamic graphics for regression diagnostics. They suggested animating graphics which could aid to understanding the effects of adding a variable to a model. In this paper, using the Cook and Weisberg's idea of animation, we propose a dynamic graphical method for residuals to display the effects of removing an observation from a model. Based on the information obtained from these animating graphics, it is possible to see the influence of outliers on influencial observations for regression diagnostics.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 춘계학술대회 논문집
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• pp.337-342
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• 2003

The dynamic load effects are conveyed to the railway bridges through tracks which are generated by moving trains The dynamic load effects may vary due to the dynamic characteristics of the applied vehicle loads and the railway bridges containing the track system. However, the track effects have been neglected or simplified by spring elements in the most studies since it is quite complex to consider the track systems in the dynamic analysis models of railway bridges. In this study, track system on railway bridges is modeled using a three-dimensional discrete-support model that can simulate the load carrying behavior of tracks. In addition, this program is developed with the precise 20-car model and a continuous PSC(prestressed concrete) box girder bridge, which is the main bridge type of Korea Train express(KTX). Three-dimensional elements are used for both. The dynamic response of railway bridges is found to be affected depending on whether the track model is considered or not. The influencing rate depends on the traveling speed and different wheel-axle distance. The dynamic bridge response is decreased remarkably by the track systems around the resonant frequency. Therefore, the resonance effect can be reduced by modifying the track properties in the railway bridge.

• Structural Engineering and Mechanics
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• 제48권1호
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• pp.103-124
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• 2013

This paper studies the static and dynamic characteristics of composite plates subjected to an arbitrary periodic load in hygrothermal environments. The material properties of composite plates are depended on the temperature and moisture. The governing equations of motion of Mathieu-type are established by using the Galerkin method with reduced eigenfunction transforms. A periodic load is taken to be a combination of axial pulsating load and bending stress in the example problem. The regions of dynamic instability of laminated composite plates are determined by solving the eigenvalue problems based on Bolotin's method. The effects of temperature rise and moisture concentration on the dynamic instability of laminated composite plates are investigated and discussed. The influences of various parameters on the instability region and dynamic instability index are also investigated. The numerical results reveal that the influences of hygrothermal effect on the dynamic instability of laminated plates are significant.

• 지식경영연구
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• 제15권4호
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• pp.57-78
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• 2014

Since team performance has become one of the core factors for companies' success, companies are putting every effort to raise team productivity. In this vein, the purpose of this study was to examine the influence of team learning behavior upon team dynamic capabilities, team effectiveness, and to verify the mediating effect of team dynamic capabilities in corporations. 312 employees were randomly selected to participate in an questionnaire survey. The result has shown that the static correlation exists between team learning behavior, team dynamic capabilities, and team effectiveness. Team dynamic capabilities mediated the relationship between team learning behavior and team effectiveness. Based on the findings, the study implies that learning behaviors among team members should be supported in order to improve its outcome, and HR representatives must help to develop dynamic capabilities.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1998년도 춘계학술대회논문집; 용평리조트 타워콘도, 21-22 May 1998
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• pp.602-607
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• 1998

Rubber materials are extensively used in various machine design application, mainly for vibration/shock/noise control devices. Over the years an enormous effort has been put into developing procedures to provide properties of rubber material for design function. However, there are still a lot of difficulties in the understanding of dynamic characteristics of the rubber components in compression. In this paper, the dynamic characteristics of rubber materials for anti-vibration under compression were investigated. Dynamic and static tests for rubber material with 3 different hardness were performed. In dynamic tests, non-resonance method, impedance method, was used to obtain the complex modulus (storage modulus and loss factor) and the effects of static pre-strain on the dynamic characteristics were investigated. Also, a relation equation between linear dynamic and nonlinear static behavior of rubber material was discussed and its usefulness to predict their combined effects was investigated.

• 소음진동
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• 제6권4호
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• pp.447-456
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• 1996

Dynamic characteristics of the bell-type structure including acoustic effects and transient dynamic problems were analyzed numerically. Natural frequencies, mode shapes and transient dynamic analysis used the finite element method with 3-D general shell element. Mode shapes and stress distributions of transient dynamic analysis were expressed by computer graphics. The method using this study was evaluated by comparision of theoretical results at reference papers(14), (15) and the experimental test using Fast Fourier Transform analyzer. Vibrational modes governing acoustic characteristics of the typical bell-type structure depended on the first flexural mode(4-0 mode) and the second flexural mode(6-0 mode). Asymmetric effects by Dangiwas, acoustic holes gave rise to beat frequencies, and the Dangjwa was found to be most effective. When impact load acted on the bell, stress concentration occured at the rim part of bell. It was found that the bell type structure should be designed thickly at the rim part in order to prevent impact load from stress concentration.