• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.2717-2719
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• 2005

Generally, biped walking is difficult to control because a biped robot is a nonlinear system with various uncertainties. In this paper, we propose a hybrid control system to improve the efficiency of position tracking performance of biped locomotion. In our control system, the wavelet neural network (WNN) based on Sliding mode controller is used as a main controller which estimates a biped robot model, and the compensated controller is proposed to compensate the estimation error. A WNN is utilized to estimate uncertain and nonlinear system parameters, where the weights of WNN are trained by adaptive laws that are induced from the Lyapunov stability theorem. Finally, the effectiveness of the proposed control system is verified through computer simulations.

• Progress in Superconductivity and Cryogenics
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• v.17 no.3
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• pp.62-66
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• 2015

The cryostat is designed for the superconducting quadrupole magnets to be used in a heavy-ion accelerator facility. The main accelerator is superconducting linac, which can accelerate a $^{238}U$ beam to 200 MeV/u (Mega electron voltage per nucleon). The cryostat for the magnet employs an innovative design primarily driven by the requirement of the compactness, user-friendliness and reliability. Also, several ancillary requirements such as background field, space restriction due to the beam line and cryostat structure need technical attentions. The development of the cryostat for three quadrupole magnets in the in-flight fragmentation separator is presented in the paper. The concept of cryogenic design is reported and the amount of cryogenic load is estimated by a relevant analysis. The structure of the cryostat to endure the heavy iron yoke including three quadrupole magnets is presented. In addition, the design as well as the performance test of the support link for the cold mass is described.

• Journal of Information Technology Applications and Management
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• v.11 no.1
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• pp.69-82
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• 2004

The role of switching costs in customer retention has been posited, but has not been subjected to rigorous empirical testing. Therefore, our main focus is on the factors that influence whether consumers will have intention to switch or stay with an incumbent technology (e.g., MS-Windows). Based on consumer survey with MS-Windows users, we find empirical support for the link between the existence of compactible software, consumer's expertise in MS-Windows and intention to stay with MS-Windows. Specifically, switching costs are found to be positively associated with the existence of compatible software. Further, the lack of expertise in MS-Windows on the part of consumers tends to increase the likelihood that they will rely on current MS-Windows, rather than switch to other alternative operating systems.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1997.10a
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• pp.413-416
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• 1997

Recently, dynamic recurrent neural networks(DRNN) for identification of nonlinear dynamic systems have been researched extensively. In general, dynamic backpropagation was used to adjust the weights of neural networks. But, this method requires many complex calculations and has the possibility of falling into a local minimum. So, we propose a new approach to identify nonlinear dynamic systems using DRNN. In order to adjust the weights of neurons, we use evolution strategies, which is a method used to solve an optimal problem having many local minimums. DRNN trained by evolution strategies with mutation as the main operator can act as a plant emulator. And the fitness function of evolution strategies is based on the difference of the plant's outputs and DRNN's outputs. Thus, this new approach at identifying nonlinear dynamic system, when applied to the simulation of a two-link robot manipulator, demonstrates the performance and efficiency of this proposed approach.

• ETRI Journal
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• v.31 no.1
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• pp.31-41
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• 2009

Optical burst switching is a promising switching paradigm for the next IP-over-optical network backbones. However, its burst loss performance is greatly affected by burst contention. Several methods have been proposed to address this problem, some of them requiring the network to be flooded by frequent state dissemination signaling messages. In this work, we present a traffic engineering approach for path selection with the objective of minimizing contention using only topological information. The main idea is to balance the traffic across the network to reduce congestion without incurring link state dissemination protocol penalties. We propose and evaluate two path selection strategies that clearly outperform shortest path routing. The proposed path selection strategies can be used in combination with other contention resolution methods to achieve higher levels of performance and support the network reaching stability when it is pushed under stringent working conditions. Results show that the network connectivity is an important parameter to consider.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.398-402
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• 1996

This paper addresses the design and the gait control of quadruped walking robot. First, we concern the mechanical and electronical(control system) hardware of walking robot, and the second is the results of experiments. The walking robot is the most suitable form to substitute fot human being. So walking robot is worthy of research. The quadruped walking robot and control system is the simplest type of walking robot, therefore we designed a small seale robot for realization of static gait. The robot is designed commpactly and its legs are constructed parallel link type and able to move freely in space. Control system consists of one upper level controller and four lower level controllers. The upper level controller plans the walking path and commands the low level controllers to follow the planned path. The main function of low level cotrollers is control of motors. Total number of motors is twealve and they operate four legs. And robot is ordered to walk and realize static wave gait.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.11
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• pp.3398-3407
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• 1996

In this paper, we derive an algorithm and develope a computer program which analyze rapidly and precisely the inverse kinematics of robotic mechanism with spatial complex chain structure based on the relative coordinates. We represent the inverse kinematic problem as an optimization problem with the kinematic constraint equations. The inverse kinematic analysis algorithm, therefore, consists of two algorithms, the main, an optimization algorithm finding the motion of independent joints from that of an end-effector and the sub, a forward kinematic analysis algorithm computing the motion of dependent joints. We accomplish simulations for the investigation upon the accuracy and efficiency of the algorithm.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.983-987
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• 2001

This paper deals with an automated computer-aided process planning system by which designer can determine operation sequences even if they have little experience in process planning of wheel bolt products by a multi-stage former. The approach to the system is based on knowledge-based rules and a process knowledge base consisting of design rules is built. Knowledge for the system is formulated from plasticity theories, empirical results and the empirical knowledge of field experts. Programs for the system have been written in AutoLISP for the AutoCAD using a personal computer and are composed of two main modules. An attempt is made to link programs incorporationg a number of expert design rules to form a useful package. Results obtained using the modules enable the designer and manufacturer of wheel bolt product to be more efficient in this field.

• Language and Information
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• v.8 no.2
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• pp.47-72
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• 2004

In general, it is assumed that a pronoun refers to the same individual as the referent of its antecedent. However, when a pronoun and its antecedent are in different information or belief states, the two may not refer to the same individual. Then a question arises what a pronoun refers to. In this paper, two cases are considered. When a pronoun occurs in an attitude context, one case is where its antecedent occurs in a belief context, and the other is where the antecedent occurs in the main context. I propose that a pronoun refers to an individual concept which links two different subjects in two different contexts, and that the selection of a proper individual concept is restricted by the discourse. So a pronoun can be used felicitously only when there is a unique individual concept supported by the individual concept introduced by the discourse and which can link two subjects in two different contexts.

• Journal of Electrical Engineering and Technology
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• v.9 no.1
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• pp.45-51
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• 2014

Distribution system is a critical link between customer and utility. The control of power loss is the main factor which decides the performance of the distribution system. There are two methods such as (i) distribution system reconfiguration and (ii) inclusion of capacitor banks, used for controlling the real power loss. Considering the improvement in voltage profile with the power loss reduction, later method produces better performance than former method. This paper presents an advanced evolutionary algorithm for capacitor inclusion for loss reduction. The conventional sensitivity analysis is used to find the optimal location for the capacitors. In order to achieve a better approximation for the current candidate solution, Opposition based Differential Evolution (ODE) is introduced. The effectiveness of the proposed technique is validated through 10, 33, 34 and85-bus radial distribution systems.