• Journal of KSNVE
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• v.10 no.4
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• pp.648-654
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• 2000

A procedure to determine the realizable optimal positions of rigid supports is suggested to get a maximum fundamental natural frequency. a measured frequency response function based substructure-coupling technique is used to model the supported structure. The optimization procedure carries out the eigenvalue sensitivity analysis with respect to the stiffness of supports. As a result of such stiffness optimization, the optimal rigid-support positions are shown to be determined by choosing the position of the largest stiffness. The optimally determined support conditions are verified to satisfy the eigenvalue limit theorem. To demonstrate the effectiveness of the proposed method, the optimal support positions of a plate model are investigated. Experimental results indicate that the proposed method can effectively find out the optimal support conditions of the structure just based on the measured frequency response functions without any use of numerical model of the structure.

• Journal of information and communication convergence engineering
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• v.5 no.3
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• pp.273-280
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• 2007

The numerical methods for finding the optimal parameters in 640 Gbps (16 channels $\times$ 40 Gbps) WDM system with optical phase conjugator (OPC) are proposed, which effectively compensate the distorted overall WDM channels. The considered optimal parameters are the OPC position and the dispersion coefficient of fibers. The numerical approaches are accomplished through two different procedures. One of these procedures is that the optimal OPC position is previously searched and then the optimal dispersion coefficient is searched at the obtained optimal OPC position. The other is the reverse of the above procedure. From the numerical results, it is confirmed that two optimal parameters depend on each other, but less related with the searching procedure. The methods proposed in this research will be expected to alternate with the method of making a symmetrical distribution of power and local dispersion in real optical link which is a serious problem of applying the OPC into multi-channels WDM system.

• Structural Engineering and Mechanics
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• v.41 no.2
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• pp.299-312
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• 2012

Stiffened coupled shear walls (SCSW) are under axial load resulting from their weight and this axial load affects the behavior of walls because of their excessive height. In this paper, based on the continuum approach, the optimal position of the stiffening beam on the stiffened coupled shear walls is investigated considering the effect of uniformly distributed axial loads. Moreover, the effect of the height of stiffened coupled shear walls on the optimal position of the stiffening beam has been studied with and without considering the axial force effect. A computer program has been developed in MATLAB and numerical examples have been solved to demonstrate the reliability of this method. The effects of the various flexural rigidities of the stiffening beam on the internal forces and the lateral deflection of the structure considering axial force effect have also been investigated.

• Journal of Korean Academy of Nursing
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• v.42 no.5
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• pp.730-737
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• 2012

Purpose: This study was done to identify the time interval to pressure ulcer and to determine the optimal time interval for position change depending on pressure ulcer risk in patients using foam mattress in intensive care units. Methods: The Braden scale score, occurrence of pressure ulcers and position change intervals were assessed with 56 patients admitted to an intensive care unit from April to November, 2011. The time to pressure ulcer occurrence by Braden scale risk group was analyzed with Kaplan-Meier survival analysis and log rank test. Then, the optimal time interval for position change was calculated with ROC curve. Results: The median time to pressure ulcer occurrence was 5 hours at mild or moderate risk, 3.5 hours at high risk and 3 hours at very high risk on the Braden scale. The optimal time interval for position change was 3 hours at mild and moderate risk, 2 hours at high and very high risk of Braden scale. Conclusion: When foam mattresses are used a slight extension of the time interval for position change can be considered for the patients with mild or moderate pressure ulcer risk but not for patients with high or very high pressure ulcer risk by Braden scale.

• The Journal of Korea Robotics Society
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• v.2 no.3
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• pp.255-261
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• 2007

We propose a optimal fusion method for localization of multiple robots utilizing correlation between GPS on each robot in common workspace. Each mobile robot in group collects position data from each odometer and GPS receiver and shares the position data with other robots. Then each robot utilizes position data of other robot for obtaining more precise estimation of own position. Because GPS data errors in common workspace have a close correlation, they contribute to improve localization accuracy of all robots in group. In this paper, we simulate proposed optimal fusion method of odometer and GPS through virtual robots and position data.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.834-839
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• 2004

In this paper, we investigate the optimal base position and joint configuration of a planar wheeled mobile manipulator in terms of manipulability measure. Taking into account the level of coordination between a manipulator and a platform, both local and global optimization problems are considered. First, based on the kinematic models of a mobile manipulator, the manipulability measures are expressed along with the analysis of the configurational dependency. Second, the geometric symmetry of a mobile manipulator in view of manipulability measure is analyzed, and for some base positions, the best and worst joint configurations are determined, Third, with reverence to the maximum, minimum, and average manipulability measures, the optimal base positions are determined, and the percent improvements due to the base relocation are discussed considering the relative scales among the platform size, the wheel radius, and the link length.

• Proceedings of the KIEE Conference
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• 2003.11b
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• pp.107-110
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• 2003

In this paper, the optimal position selection of error sensors and transducers to attenuate interior noise from outside noise sources using active control techniques is presented. To get an optimal control characteristics in adaptive noise control systems, it is necessary to optimize the positions of sensors and transducers. A new type of simulated annealing method has been proposed as searching technique to find optimal transducers and sensors positions in which the sum of the squared pressures at sensor position in an enclosure can be best minimized. Computer simulations and experiments have been performed to show the effectiveness of the proposed method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.7A
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• pp.542-549
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• 2005

In this paper, the optimal pump light power of optical phase conjugator (OPC) and the compensation characteristics of distorted WDM channel signals are numerically investigated, when the OPC with highly-nonlinear dispersion shifted fiber (HNL-DSF) not be placed at the mid-way of total transmission length. The total dispersion of former half section and latter half section is assumed to be same each other in this approach. It is confirmed that, in WDM transmission systems with OPC deviated from the mid-way, the pump light power for best compensation must be flexible selected depending on the OPC position. This optimal pump light power is gradually increased as the OPC is gradually closer to the receiver. Consequently, it is possible to establish the compensation system independent on the OPC position by setting optimal pump light power connected with the OPC position.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.344-344
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• 2000

Recently, the demand for high precision and large stroke in linear positioning systems is increasing in industry. A coarse-fine position control system composed of a linear motor and a piezoelectric actuator has such characteristics. Many optimal control laws have been applied to the position control of coarse-fine actuators but most of them did not take account into constraints. In this study, model predictive control (MPC) method with constraints is applied to the position control of the coarse-fine actuator and the performance of MPC is compared with those of conventional control laws.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.6
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• pp.681-687
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• 2023

The selection technique for optimal operation position selection technique is used to present the initial bow and stern draft with minimum resistance, for achievingthat is, the optimal fuel consumption efficiency at a given operating displacement and speed. The main purpose of this studypaper is to develop a program to select the optimal operating position with maximum energy efficiency under given operating conditions based on the effective power data of the target ship. This program was written as a Python-based GUI (Graphic User Interface) usingbased on artificial intelligence techniques sucho that ship owners could easily use the GUIit. In the process, tThe introduction of the target ship, the collection of effective power data through computational fluid dynamics (CFD), the learning method of the effective power model using deep learning, and the program for presenting the optimal operation position using the deep neural network (DNN) model were specifically explained. Ships are loaded and unloaded for each operation, which changes the cargo load and changes the displacement. The shipowners wants to know the optimal operating position with minimum resistance, that is, maximum energy efficiency, according to the given speed of each displacement. The developed GUI can be installed on the ship's tablet PC and application and used to determineselect the optimal operating position.