• Proceedings of the KSME Conference
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• 2001.11a
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• pp.848-852
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• 2001

A new approach to the design of bank note counters is suggested. Modern bank note counters are equipped with several types of sensors for counting and detection of counterfeit bank notes. To achieve higher speed of counting while maintaining the sensing capability, longitudinal feeding scheme is proposed. Several merits of longitudinal feeding are discussed. Taguchi method is used for the optimization of the feeding mechanism.

• International Journal of High-Rise Buildings
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• v.5 no.4
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• pp.305-318
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• 2016

In the design of super-tall towers, engineers often find the conventional frame systems used in countless buildings in the past decades incapable of providing the required form, performance and constructability demanded by super-tall heights. The strength of the diagrid as a structural system in high-rise towers is the total flexibility it affords the designer as an adaptable, efficient and buildable scheme. Using fundamental engineering principles combined with modern computational tools, designers can take minimum load path forms to create rationalized diagrid geometries to create optimized, highly efficient towers. The use of diagrid frames at SOM has evolved as a structural typology beginning with the large braced frames on the John Hancock Center and continued in modern applications proving to be a powerful system in meeting the demands of supertall buildings.

• Journal of the Ergonomics Society of Korea
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• v.11 no.1
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• pp.81-92
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• 1992

A two-dimensional static biochemical model of lower extremity in the seated posture was developed to assess muscular activities of lower extremity required for a variety of foot pedal operations. We found that the double linear optimization method that has been used for modelling articulated body segments does no predict the forces generated by biarticular muscles reasonably, so the revised double linear optimization scheme was used to consider the synergistic effects of biarticular muscles in our model, assuming that the muscle forces are distributed proportionally based on their physiological cross sectional area. The model incorporated three rigid body se- gments with six muscles to represnet lower extremity. For the model validation, three male subjects performed the experiments in which EMG activities of six lower extremity muscles were measured. Predicted muscle forces were compare with the corresponding EMG amplitudes and it showed no statistical difference. The model being developed can be used to design and assess pedal and foot-related tool design.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.3
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• pp.177-185
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• 2003

Current issues of receding horizon control scheme are reviewed. The basic idea of receding horizon control is presented first. For unconstrained and constrained systems, the results of closed-loop stability in receding horizon control are surveyed. We investigate the two categories of robustness of receding horizon control : stability robustness and performance robustness. The existing optimization algorithm to solve receding horizon control problem is briefly mentioned. It is shown that receding horizon control has been extended to nonlinear systems without losing good properties such as stability and robustness. Many industrial applications are reported along with extensive references related to receding horizon control.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1505-1506
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• 2008

In this paper, a robust adaptive backstepping control is developed for efficiency optimization of induction motors with uncertainties. The proposed control scheme consists of efficiency flux control(EFC) using a sliding mode adaptive flux observer and robust speed control(RSC) using a function approximation for mechanical uncertainties. In EFC, it is important to find the flux reference to minimize power losses of induction motors. Therefore, we proposed the optimal flux reference using the electrical power loss function. The sliding mode flux observer is designed to estimate rotor fluxes and variation of inverse rotor time constant. In RSC, the unknown function approximation technique employs nonlinear disturbance observer(NDO) using fuzzy neural networks(FNNs). The proposed controller guarantees both speed tracking and flux tracking. Simulation results are presented to illustrate the effectiveness of the approaches proposed.

• Journal of Korean Institute of Industrial Engineers
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• v.26 no.2
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• pp.117-127
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• 2000

In this paper, we propose a new convex combination weight rule for the cross decomposition method which is known to be one of the most reliable and promising strategies for the large scale optimization problems. It is called generalized cross decomposition, a modification of linear mean value cross decomposition for specially structured linear programming problems. This scheme puts more weights on the recent subproblem solutions other than the average. With this strategy, we are having more room for selecting convex combination weights depending on the problem structure and the convergence behavior, and then, we may choose a rule for either faster convergence for getting quick bounds or more accurate solution. Also, we can improve the slow end-tail behavior by using some combined rules. Also, we provide some computational test results that show the superiority of this strategy to the mean value cross decomposition in computational time and the quality of bounds.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.825-829
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• 2009

In this paper, we examine the fundamental performance of image coding schemes based on multipulse model. First, we introduce several kinds of pulse search methods (i.e., correlation method, pulse overlap search method and pulse amplitude optimization method) for the model. These pulse search methods are derived from auto-correlation function of impulse responses and cross-correlation function between host signals and impulse responses. Next, we explain the basic procedure of multipulse image coding scheme, which uses the above pulse search methods in order to encode the high frequency component of an original image. Finally, by means of computer simulation for some test images, we examine the PSNR(Peak Signal-to-Noise Ratio) and computational complexity of these methods.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.686-691
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• 2001

Structural optimization often require the evaluation of design sensitivities. The Semi Analytic method(SAM) is popular for shape optimization because this method has several advantages. But when relatively large rigid body motions are identified for individual elements, the SA method shows severe inaccuracy. In this paper, the improvement of design sensitivities corresponding to the rigid body mode is evaluated by exact differentiation of the rigid body modes. Moreover, the error of the SA method caused by numerical difference scheme is alleviated by using a series approximation for the sensitivity derivatives and considering the higher order terms.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.4
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• pp.593-600
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• 2003

Structural optimization often requires the evaluation of design sensitivities. The Semi Analytic Method(SAM) fur computing sensitivity is popular in shape optimization because this method has several advantages. But when relatively large rigid body motions are identified for individual elements. the SAM shows severe inaccuracy. In this study, the improvement of design sensitivities corresponding to the rigid body mode is evaluated by exact differentiation of the rigid body modes. Moreover. the error of the SAM caused by numerical difference scheme is alleviated by using a series approximation for the sensitivity derivatives and considering the higher order terms. Finally the present study shows that the refined SAM including the iterative method improves the results of sensitivity analysis in dynamic problems.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.9
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• pp.392-398
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• 2006

Maintenance scheduling of generating units (MSU) has strategic dimension in an oligopolistic market. Strategic MSU of gencos can affect a market power through capacity withdrawal which is related to bidding strategy in an generation wholesale market. This paper presents a combined framework that models the interrelation between competitive bidding and strategic MSU. The combined game model is represented as some sub-optimization problems of a market operator (MO) and gencos, that should be solved through bi-level optimization scheme. The gradient method with dual variables is also adopted to calculate a Nash Equilibrium (NE) by an iterative update technique in this paper. Illustrative numerical example shows that NE of a supply function equilibrium is obtained properly by using proposed solution technique. The MSU made by MO is compared with that by each genco and that under perfect competition market.