• Structural Engineering and Mechanics
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• v.20 no.2
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• pp.143-160
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• 2005

Modal analysis of cracked cantilever composite beams, made of graphite-fibre reinforced polyamide, is studied. By using the finite element and component mode synthesis methods, a numeric model applicable to investigate the vibration of cracked composite beams is developed. In this new approach, from the crack section, the composite beam separated into two parts coupled by a flexibility matrix taking into account the interaction forces. These forces are derived from the fracture mechanics theory as the inverse of the compliance matrix calculated with the proper stress intensity factors and strain energy release rate expressions. Numerical results are obtained for modal analysis of composite beams with a transverse non-propagating open crack, addressing the effects of the location and depth of the crack, and the volume fraction and orientation of the fibre on the natural frequencies and mode shapes. By means of modal data, the position and dimension of the defect can be found. The results of the study confirmed that presented method is suitable for the vibration analysis of cracked cantilever composite beams. Present technique can be easily extended to composite plates and shells.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2019.11a
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• pp.22-23
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• 2019

The emerging Versatile Video Coding (VVC) standard introduces Bi-prediction with CU-level Weights (BCW) to enhance the bi-predictive prediction. The syntax element of BCW index is adaptively coded according to the value of NoBackwardPredFlag which indicates if there is no future picture in the display order among the reference pictures, and it can violate the flexibility of codec and cause the dependency issue. This paper proposes BCW clean-up design that allows all weights can be parsed without any condition. The experimental results show negligible BD-rate losses while resolving the issues.

• Journal of Mechanical Science and Technology
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• v.18 no.9
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• pp.1529-1536
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• 2004

A structure is broken down into a number of substructures by means of the finite element method and the substructures are synthesized for the complete structure. The divided substructures take two types: fixed-free and free-free elements. The flexibility and stiffness matrices of the free-free elements are the Moore-Penrose inverse of each other. Thus, it is not easy to determine the equilibrium equations of the complete structure composed of two mixed types of substructures. This study provides the general form of equilibrium equation of the entire structure through the process of assembling the equilibrium equations of substructures with end conditions of mixed types. Applications demonstrate that the proposed method is effective in the structural analysis of geometrically complicated structures.

• International Journal of Contents
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• v.7 no.1
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• pp.52-57
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• 2011

The organizational theory and design in future encourages us to bring a fluid perspective to the problems and challenges face. Organizational structure, strategy, management style, teamwork, organizational change, and even products and services can be vitalized and re-formed through creative images that allow us to act in new ways. Leaders and educators sat all levels must gain comfort in dealing with the insights and implications of diverse perspectives. In a leadership paradigm in action, leaders and educators who have more flexibility and willingness to create a learning organization are successful in improving productivity and student empowerment. The key element to organizational structure and changes for interior design education becomes communications. Finally, we need to recognize that despite its roots in mechanistic thinking, organization is a creative process of imagination. We organize as we imagine, and it is always possible to imagine in new ways.

• Korean Institute of Interior Design Journal
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• no.38
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• pp.201-208
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• 2003

Shipboard architecture and design has now become a specialty In its own right. As rationalized as the process of ship' design and built is, it continues to produce some remarkable fleet image. Cruise line has created a number of the hall mark identities and the interior design features of its own. It is to develop a design theme for a reference ship which sets a particular image for later new buildings to follow in same class. When a new class Is created later, key design element will be retained, with some items being changed and new ideas introduced. Thus the approach has the flexibility to grow and change as the industry itself evolves and diversifies. There are a number of notable examples which illustrate how different line are thus able to create and maintain unique product hallmarks and identities through the interior design of their fleets.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.836-840
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• 1995

Recently, the motor-integrated spindle spindle systems have been used to simplify the machine tool structure, to improve the motion flexibility of machine tool, and to perform the high-speed machining. In this study, a static and dynamic analysis system for motor-integrated high-speed spindle systems is developed based on Timoshenko theory, finite element method and windows programming techniques. Since the system has various analysis modules related to static deformation analysis, modal analysis, frequency response analysis, unbalance response analysis and so on, it is useful in performing systematically the design and evaluation processes of motor-integrated high-speed spindle systems under windows GUI encironment.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.160-165
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• 1998

The sub-resonance modes can be easily excited by the assembling tolerance in the asymmetric type optical pick-up actuators, compared with the symmetric type. In this paper, we propose the novel method for reducing the vibration due to the sub-resonance modes where undesirable modes can be decreased by adding the damping, which can be achieved by increasing the flexibility of holder PCB, against to the sub-resonance modes. Using the finite element method, the change of mode shapes is investigated as the shape of holder PCB is modified. Experimental results support that the proposed method reduces remarkably the vibration of sub-resonance modes of the optical pick-up actuator.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.10
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• pp.1364-1369
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• 2002

This paper introduces the development of the analysis and design program of valve train system. In order to verify the stability of design and improve the performance of system efficiently, it is required that integrated and interactive simulation program. The presented program is developed in the base of the object-oriented, capsulation, modulization, OLE (objected linking and embedding) and various design theory. It contains the expandability and flexibility of the structure. In addition to that, it is programmed to make the convenient user interface by using the visualization programming. This program can support the modification of the valve element as well as the development of the valve train system in the beginning of design. It is expected to save the cost and time for the design of valve train system.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.19 no.4
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• pp.12-17
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• 2011

This paper gives a review of finite element model for the analysis of fastening as practical points of view. Different mechanical properties of plate-fastener systems are analyzed. Calculations of the system properties are described as well as the technique of their application in model. Analysis has been performed for calculating the load distribution in multi-joint and the results are compared using the several models. The effects of fastener-hole clearance on the load distribution in multifastener joints are presented. And the stress analysis method have been reviewed for failure analysis of mechanical joint of composite laminate.

• Structural Engineering and Mechanics
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• v.34 no.4
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• pp.475-490
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• 2010

It is the intention of this study to synthesize the effects of double-edge cracks on the dynamic characteristics of a beam. The stiffness matrix is first determined for a Timoshenko beam containing two same-line edge cracks. The presented model is then developed for elements with two parallel double-sided cracks, considering the interaction between the stress fields of adjacent cracks. Finally, a finite element code is implemented, to examine the influence of depth and location of double cracks, on the natural frequencies of the damaged system.