• Journal of the Korean Institute of Navigation
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• v.15 no.3
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• pp.1-11
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• 1991

As increasing needs of marine transportation , world merchant fleet and ship's size were enlarged and it caused frequent disasters in human lives and natural environment. By the reason of the above, they started to establish the Vessel Traffic System (VTS) at the European coast in 1960' and most of advanced contries established and managed it to prevent the sea traffic accidents in these days. The concept of traffic control at sea can be divided into three types. First, the initial gathering of informations about ship's identity and movement etc.. Second, monitoring of the traffic flow and amendment of instructions. Third , organization and direction of ships by allocating routes and speeds. Where the goal of traffic control is safety of traffics and developing effectiveness of navigation channel, if traffic volume is less tan channel capacity then the above first or second level of control would be sufficient but if it is bigger than that , more positive policy of control should be adopted as same as third type of the above. In this paper where the strategy of VTS is focused on the control of traffic density to be spread equality, as possible , all over the navigation channels and also improvement of effectiveness , it suggests algorithm to assign the vessels to the channels with balanced traffic density , and other algorithms using D.P. to sequence the vessels assigned to one channel in optimum order which decreases the mean waiting time in sense of channel effectiveness with numerical examples.

• Smart Structures and Systems
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• v.19 no.1
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• pp.21-31
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• 2017

To control the stochastic vibration of a vibration-sensitive instrument supported on a beam, the beam is designed as a sandwich structure with magneto-rheological visco-elastomer (MRVE) core. The MRVE has dynamic properties such as stiffness and damping adjustable by applied magnetic fields. To achieve better vibration control effectiveness, the optimal bounded parametric control for the MRVE sandwich beam with supported mass under stochastic and deterministic support motion excitations is proposed, and the stochastic and shock vibration suppression capability of the optimally controlled beam with multi-mode coupling is studied. The dynamic behavior of MRVE core is described by the visco-elastic Kelvin-Voigt model with a controllable parameter dependent on applied magnetic fields, and the parameter is considered as an active bounded control. The partial differential equations for horizontal and vertical coupling motions of the sandwich beam are obtained and converted into the multi-mode coupling vibration equations with the bounded nonlinear parametric control according to the Galerkin method. The vibration equations and corresponding performance index construct the optimal bounded parametric control problem. Then the dynamical programming equation for the control problem is derived based on the dynamical programming principle. The optimal bounded parametric control law is obtained by solving the programming equation with the bounded control constraint. The controlled vibration responses of the MRVE sandwich beam under stochastic and shock excitations are obtained by substituting the optimal bounded control into the vibration equations and solving them. The further remarkable vibration suppression capability of the optimal bounded control compared with the passive control and the influence of the control parameters on the stochastic vibration suppression effectiveness are illustrated with numerical results. The proposed optimal bounded parametric control strategy is applicable to smart visco-elastic composite structures under deterministic and stochastic excitations for improving vibration control effectiveness.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.140-145
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• 2001

Various control algorithms are available to suppress the vibration of a system subjected to disturbances. LQ algorithm is simple and easy to implement the hardwares, but it lacks robustness for uncertainties and often causes difficulty in determining the weighting matrices. This study focuses on the effectiveness ILQ(Inverse Linear Quadratic optimal control) algorithm as the alternative to LQ applied to control the vibration of a building under the seismic excitation. The building is of moment resisting steel frames and assumed to behave within the elastic range. The brief overview of LQ and ILQ algorithms is introduced, and the displacement responses of the structure using ILQ algorithm are compared with those obtained from LQ control. The magnitude of control forces are also determined and compared for both LQ and ILQ algorithm.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2008.10a
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• pp.348-352
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• 2008

KJCCS(Korean Joint Command & Control System) is a system that integrate each military tactics C4ISR into JCS(Joint Chiefs of Staff) level. It is established in major CP(Commanding Post) and provides all battlefield situation in real time by sharing that between connection troops. The objective of this study is to suggest a way for the measurement of force improvement effectiveness of KJCCS. C2 model is applied to measure force improvement effectiveness of KJCCS. This study will be also present a requirement logic for C4ISR system acquisition later.

• Journal of Korean Academy of Nursing Administration
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• v.11 no.4
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• pp.415-423
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• 2005

Purpose: The purpose of this research is to discover the effects of REBT group counseling on the self-efficacy and organizational effectiveness of nurses with high scores on dysfunctional attitude scale. Method: There wewe 21 subjects in the experimental group and 25 subjects in the control group. This treatment lasted for eight weeks. Each week, a two and half hour long session was cinducted. Results: The experimental groups showed that significant statistical differences compared with the control groups in the score of self-efficacy, job-satisfaction, organizational commitment, and nursing performance. Conclusion: These results imply that REBT group counseling could be utilized as good nursing intervention to enhance self-efficacy, organizational effectiveness at the general hospital.

• Proceedings of the Korean Nuclear Society Conference
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• 2005.10a
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• pp.1001-1002
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• 2005

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.3
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• pp.1-12
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• 2012

This paper aims at developing an active expressway entrance control effectiveness analysis tool which operators can utilize and manage traffic based on current traffic condition. For this, after identifying the current problems of tollgate-based entrance policy being used, a new set of decision element such as congestion index, decision criteria for congestion, and congestion management unit has been proposed together with the procedure of newly developed tollgate control policy. Three key parts developed are traffic condition identification module, tollgate metering module, and travel speed calculation module. Some measures of effectiveness were also identified and the newly developed effectiveness analysis tool produced better result. According to classification of traffic condition by reference speed as 80km/h, the improved tollgate entrance procedure increased 21.5% in average travel speed compared with Do-Nothing case and also increased 8.8% compared with current entrance control method.

• Wind and Structures
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• v.36 no.2
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• pp.91-103
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• 2023

Tuned liquid dampers (TLDs) are increasingly being used as efficient dynamic vibration absorbers to mitigate wind-induced vibration in super high-rise buildings. However, the damping characteristics of screens and the control effectiveness of actual structures must be investigated to improve the reliability of TLDs in engineering applications. In this study, a numerical TLD model is developed using computational fluid dynamics (CFD) and a simulation method for achieving the coupled vibration of the structure and TLD is proposed. The numerical results are verified using shaking table tests, and the effects of the solidity ratio and screen position on the TLD damping ratios are investigated. The TLD control effectiveness is obtained by simulating the wind-induced vibration response of a full-scale structure-TLD system to determine the optimal screen solidity ratio. The effects of the structural frequency, damping ratio, and wind load amplitude on the TLD performance are further analyzed. The TLD damping ratio increases nonlinearly with the solidity ratio, and it increases with the screens towards the tank center and then decreases slightly owing to the hydrodynamic interaction between screens. Full-scale coupled simulations demonstrated that the optimal TLD control effectiveness was achieved when the solidity ratio was 0.46. In addition, structural frequency shifts can significantly weaken the TLD performance. The control effectiveness decreases with an increase in the structural damping ratio, and is insensitive to the wind load amplitude within a certain range, implying that the TLD has a stable damping performance over a range of wind speed variations.

• Journal of Intelligence and Information Systems
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• v.17 no.1
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• pp.71-90
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• 2011

This study was designed to empirically analyze the effect of control activities(physical, managerial and technical securities) of information protection on organizational effectiveness and the mediating effects of information application. The result was summarized as follows. First, the effect of control activities(physical, technical and managerial securities) of information protection on organizational effectiveness showed that the physical, technical and managerial security factors have a significant positive effect on the organizational effectiveness(p < .01). Second, the effect of control activities(physical, technical and managerial securities) of information protection on information application showed that the technical and managerial security factors have a significant positive effect on the information application(p < .01). Third, the explanatory power of models, which additionally put the information protection control activities(physical, technical and managerial securities) and the interaction variables of information application to verify how the information protection control activities( physical, technical and managerial security controls) affecting the organizational effectiveness are mediated by the information application, was 50.6%~4.1% additional increase. And the interaction factor(${\beta}$ = .148, p < .01) of physical security and information application, and interaction factor(${\beta}$ = .196, p < .01) of physical security and information application among additionally-put interaction variables, were statistically significant(p < .01), indicating the information application has mediated the relationship between physical security and managerial security factors of control activities, and organizational effectiveness. As for results stated above, it was proven that physical, technical and managerial factors as internal control activities for information protection are main mechanisms affecting the organizational effectiveness very significantly by information application. In information protection control activities, the more all physical, technical and managerial security factors were efficiently well performed, the higher information application, and the more information application was efficiently controlled and mediated, which it was proven that all these three factors are variables for useful information application. It suggested that they have acted as promotion mechanisms showing a very significant result on the internal customer satisfaction of employees, the efficiency of information management and the reduction of risk in the organizational effectiveness for information protection by the mediating or difficulty of proved information application.

• Smart Structures and Systems
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• v.4 no.4
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• pp.407-428
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• 2008

The nonlinear mechanics of cable vibration is caught either by analytical or numerical models. Nevertheless, the choice of the most appropriate method, in consideration of the problem under study, is not straightforward. A feedback control policy might even enhance the complexity of the system. Thus, in order to design a suitable controller, different approaches are here adopted. Devices mounted transversely to the cable in the two directions, close to one of its ends, supply the feedback control action based on the observation of the response in a few points. The low order terms of the control law are, at first, analyzed in the framework of linear models. Explicit analytic solutions are derived for this purpose. The effectiveness of high order terms in the control law is then explored by means of a finite element model(FEM), which accounts for high order harmonics. A suitably dimensional analytical Galerkin model is finally derived, to investigate the effectiveness of the proposed control strategy, when applied to a physical model.