• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.11
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• pp.1119-1125
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• 2009

The coupled fluid-structure interaction problem is analyzed using the theoretical method to investigate the coupled vibration characteristics of functionally graded material(FGM) cylindrical shells conveying an incompressible, inviscid fluid. Material properties are assumed to vary continuously through the thickness according to a power law distribution in terms of the volume fraction of the constituents. The steady flow of fluid is described by the classical potential flow theory. The motion of shell represented by the first order shear deformation theory(FSDT) to account for rotary inertia and transverse shear strains. The effect of internal fluid can be taken into consideration by imposing a relation between the fluid pressure and the radial displacement of the structure at the interface. Numerical examples are presented and compared with exiting results.

• Management & Information Systems Review
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• v.3
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• pp.439-460
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• 1999

The purpose of this paper is to compare the characteristics between group that has only one credit card and group that has multiple credit cards in each stage of purchase decision making based on the literature in consumer behavior. Results indicated that (1) The number of credit cards that consumers has was affected by internal factor and reference factor, (2) depending on the number of credit cards, usage frequency, amount, and duration were differently showed and (3) inertia, point accumulation, and convenience were founded as determinants of using credit cards. Finally, theoretical and managerial implications of these findings are discussed.

• Proceedings of the KIEE Conference
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• summer
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• pp.821-823
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• 2004

In this paper, a backstepping speed controller applied in SRM is presented. The driver of SRM is generally planned with a PI controller. A PI controller is becomes a satisfied structure in the system. it is used in position and speed control loops. However, when the system parameter uncertainties large inertia and load disturbance, it will not be able to expect a satisfied efficiency. Therefore, a backstepping control law was researched, which is able application even to a linear system as well as a nonlinear and it is more excellent than a origin adaptive control law. In this paper, a backstepping control law applied the drive system of SRM was used in the drive controller. The computer simulation result clearly show that the applied backstepping controller can track the speed reference signal generated by internal signals.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.248-251
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• 2004

The vibrational behavior of a front load washing machine is heavily influenced by the floor stiffness on which the washing machine is installed. In case the floor stiffness is extremely low like a wooden floor (we call it a 'soft floor, S/F'), it is quite probable that a washer's rigid body mode exists in the operating frequency range. In this case, the outer frame vibration level would be very high, but the mitigation scheme is quite limited except the excitation force abatement by acquisition of the optimal inertia in the internal vibratory system and the diaphragm's stiffness with the minimum force transfer.

• Journal of the Institute of Convergence Signal Processing
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• v.6 no.3
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• pp.148-156
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• 2005

The purpose of this paper is to propose an approach to design a robust servo controller based on the mixed $H_2/H_{\infty}$ theory, and confirm its validity by applying to a benchmark problem. First, the existing $H_{\infty}$ servo problem is modified to a structure for the mixed $H_2/H_{\infty}$ control problem by virtue of the internal model principle. By making use of proposed structure, we can divide specifications required in the robust servo system design into $H_2$ and $H_{\infty}$ performance criteria, respectively. It is shown that the proposed design approach is quite effective through an application to a three inertia benchmark problem.

• Journal of the Korean Society for Advanced Composite Structures
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• v.6 no.1
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• pp.14-20
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• 2015

In this study, we propose an innovative lateral force distribution building system between tall buildings by utilizing the difference of moment of inertia, as the alternative design for highly integrated city area. Considering a tri-axial symmetric conditions and boundary conditions for the three-dimensional building structure system, a two-dimensional model is composed. In the proposed indeterminate structural model, important design variables are determined for obtaining minimum horizontal deflections, reactions and bending moments at the ground level of the buildings. Regarding a case of the provided two spatial structures connected to 4 buildings, the optimum location of middle located spatial structure is 45% from the top of the building, which minimize the end moments at the bottom of the buildings. In the considered verification examples, reduced drifts at the top location of the building systems are validated against static wind pressure loads and static earthquake loads. The suggested hybrid building system will improve the safety and reliability of the system due to the added internal truss-dome structures in terms of more than 30% reduced drift and vibration through the development of convergence of tall buildings and spatial structures.

• Journal of Cadastre & Land InformatiX
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• v.46 no.2
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• pp.107-122
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• 2016

This paper examines the problems of officetel management and tests three types of hy-pothesis; use of officetel, the numbers of officetel, and ownership period to derive the efficient management in officetel as typical profitable real estate using survey data of officetel management satisfaction in Teheranro, Seoul. The problems classifies institutional inertia and lacks of management mind. This paper approaches to the internal and external problem concerning management from the viewpoint of actual owners getting out of fragmental investment value and investigates management solutions in the cost as well as institution aspect.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.3
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• pp.317-322
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• 1998

Generally, the conventional fish size grading methods just adopt the mechanical technique. So the grading methods have a problem such that the graded fish is easy to hurt on the skin and in the internal organs. In this paper, a fish size grading machine is developed using an image processing method. The grading method is based on the principal axis theorem. The length and projected area of a fish are obtained by getting the principal axis and the product of inertia moment on the captured image of a target fish. The developed machine uses an uncontact technique that the target fishes go through the front side of the CCD camera. So the above stated problem can be improved. The performance of this method is discussed with the experimental results.

• International Journal of Control, Automation, and Systems
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• v.5 no.5
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• pp.547-558
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• 2007

This paper proposes a simpler solution to the stabilization problem of a special class of nonlinear underactuated mechanical systems which includes widely studied benchmark systems like Inertia Wheel Pendulum, TORA and Acrobot. Complex internal dynamics and lack of exact feedback linearizibility of these systems makes design of control law a challenging task. Stabilization of these systems has been achieved using Energy Shaping and damping injection and Backstepping technique. Former results in hybrid or switching architectures that make stability analysis complicated whereas use of backstepping some times requires closed form explicit solutions of highly nonlinear equations resulting from partial feedback linearization. It also exhibits the phenomenon of explosions of terms resulting in a highly complicated control law. Exploiting recently introduced Dynamic Surface Control technique and using control Lyapunov function method, a novel nonlinear controller design is presented as a solution to these problems. The stability of the closed loop system is analyzed by exploiting its two-time scale nature and applying concepts from Singular Perturbation Theory. The design procedure is shown to be simpler and more intuitive than existing designs. Design has been applied to important benchmark systems belonging to the class demonstrating controller design simplicity. Advantages over conventional Energy Shaping and Backstepping controllers are analyzed theoretically and performance is verified using numerical simulations.

• Journal of Korean Academy of Rural Health Nursing
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• v.15 no.1
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• pp.1-8
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• 2020

Purpose: This purpose of this study was to develop a disaster and safety practice measurement tool for elderly people in rural areas. Methods: The tool for this study was developed and validated according to DeVellis' scale development process. The construct validity of the instrument was analyzed by major analysis of Varimax rotation, and the internal inertia was verified by Cronbach's ⍺. Results: The final scale was a 4-point scale, consisting of 23 items in 7 domains. The total explanation was 54.1% and the Cronbach's ⍺ was .80. Conclusion: The results of this study should be useful to assess elders' perception of the importance of safety management for elders.