• Transactions of the Korean Society of Automotive Engineers
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• v.2 no.1
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• pp.106-115
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• 1994

A parallel integration approach is proposed for real-time simulation of controlled mechanical systems. The proposed approach, which employs the dual-rate integration method in a parallel computing environment, is developed to deal with stiffness and high frequency characteristics of the controlled mechanical systems effectively. Numerical experiments are performed to demonstrate the effectiveness of the approach in shared memory multiprocessors, Alliant FX/8 and Alliant FX/80.

• Earthquakes and Structures
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• v.7 no.2
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• pp.119-139
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• 2014

A new method is proposed for random vibration anaylsis of hysteretic systems subjected to non-stationary random excitations. With the Bouc-Wen model, motion equations of hysteretic systems are first transformed into quasi-linear equations by applying the concept of equivalent excitations and decoupling of the real and hysteretic displacements, and the derived equation system can be solved by either the precise time integration or the Newmark-${\beta}$ integration method. Combining the numerical solution of the auxiliary differential equation for hysteretic displacements, an explicit iteration algorithm is then developed for the dynamic response analysis of hysteretic systems. Because the computational cost for a large number of deterministic analyses of hysteretic systems can be significantly reduced, Monte-Carlo simulation using the explicit iteration algorithm is now viable, and statistical characteristics of the non-stationary random responses of a hysteretic system can be obtained. Numerical examples are presented to show the accuracy and efficiency of the present approach.

• Journal of the Korea Safety Management & Science
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• v.16 no.1
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• pp.79-88
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• 2014

The rapid growth of complexity and scale can be witnessed in the design and development of modern systems. As such, the severity of damages in the occasional accidents has attracted great deal of attention lately. Although a variety of methods have so far been studied to overcome or reduce the disastrous results of hazards, the issues seem still persistent and even complicated due to the situation mentioned above. The concept of functional safety has been regarded as one approach to handling the matters by shifting up to the functions level from the consideration of each physical component itself. The outcomes of those efforts would be the international standards on functional safety such as IEC 61508 and its relatives including IEC 62278, EN 50128, ISO26262, and so on. In this paper, a method of how hazards can be analyzed to be coped with those standards has been studied. In the method proposed, the systems modeling language (SysML) is playing a key role to model and analyze the hazards from the viewpoint of functional safety. The approach taken has been applied in the analysis of the hazards in railroad systems. In spite of focusing on the individual components hazards, the method based on functional safety has analyzed them collectively with the added effect of identifying the cause originated from the interface between the functions.

• Journal of the Korean Institute of Intelligent Systems
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• v.13 no.4
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• pp.381-385
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• 2003

We suggest a method which reduces the search space of a model-base on multiple-view approach for polyhedral object recognition using the ART-1 neural network. In this approach, the model-base is consisted of extracted features from two-dimensional projections observed at the predetermined viewpoints of a viewing sphere enclosing the object.

• Journal of Electrical Engineering and Technology
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• v.3 no.3
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• pp.320-330
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• 2008

This paper presents an improved dynamic programming (IDP) approach to solve the economic power dispatch problem including transmission losses in power systems. A detailed mathematical derivation of recursive dynamic programming approach for the economic power dispatch problem with transmission losses is presented. The transmission losses are augmented with the objective function using price factor. The generalized expression for optimal scheduling of thermal generating units derived in this article can be implemented for the solution of the economic power dispatch problem of a large-scale system. Six-unit, fifteen-unit, and forty-unit sample systems with non-linear characteristics of the generator, such as ramp-rate limits and prohibited operating zones are considered to illustrate the effectiveness of the proposed method. The proposed method results have been compared with the results of genetic algorithm and particle swarm optimization methods reported in the literature. Test results show that the proposed IDP approach can obtain a higher quality solution with better performance.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.182-186
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• 1997

This paper presents a mathematical approach to implementing distributed optimal power flow (OPF), wherein a regional decomposition technique is adopted to parallelize the OPF. Three mathematical decomposition coordination methods are introduced firs to implement the proposed distributed scheme: the Auxiliary Problem Principle (APP), the Predictor-Corrector Proximal Multiplier Method (PCPM), and the Alternating Direction Method (ADM). Then two alternative schemes for modeling distributed OPF are introduced; the Dummy Generator-Dummy Generator (DGDG) scheme and Dummy Generator-Dummy Load (DGDL) scheme. We present the mathematical analyses of the proposed approach, and demonstrate the approach on several test, systems, including IEEE Reliability Test Systems and parts of the ERCOT (Electric Reliability Council of Texas) system.

• Journal of the Korean Society of Systems Engineering
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• v.10 no.1
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• pp.17-32
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• 2014

The trade-off studies in the concept development stage to assess the relative goodness of alternative systems concepts for AE (architect engineering) design for the Barge Mounted SMR (BMSMR) is introduced. With respect to design margin, system performance, schedule and risk, the design selection is cond ucted using the following characteristics; barge mobility, system safety under the natural disaster (seismic), power output, interfacing with the other system, and the additional supporting functions as desalination. There are three findings that should be remedied; deficiencies in the assumed characteristics of the system being modeled, deficiencies in the test model, and excessively stringent system requirements. This study is performed using systems engineering approach with trade off matrix method. In order to execute this work, concept development stage is divided into three (3) phases as NA (needs analysis), CE (concept exploration), and CD (concept definition).

• Transactions on Control, Automation and Systems Engineering
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• v.4 no.1
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• pp.56-61
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• 2002

In this paper we describe an approach to coordinating the motion of a human with a mobile robot moving in a populated, continuously changing. natural environment. Our test application is a wheelchair accompanying a person through the concourse of a railway station moving side by side with the person. Our approach is based on a method for motion planning amongst moving obstacles known as Velocity Obstacle approach. We extend this method by a method for tracking a virtual target which allows us to vary the robot's heading and velocity with the locomotion of the accompanied person and the state of the surrounding environment.

• Journal of Korean Institute of Industrial Engineers
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• v.39 no.5
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• pp.383-392
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• 2013

Taguchi method is a technique widely used in industries to attain a reliable quality even under existence of various noise variables. Basically, it relies on the interactions between the controllable and the noise factors. Under insignificant interactions between the design parameters and noises, the effectiveness of Taguchi methodology will be doubtful. Furthermore, existence of strong interactions among controllable factors may undermine the power of Taguchi approach. An abundant crop may be expected by a well planned Taguchi approach. A well designed set of experiments is one of the important prerequisites for its successful result. For this, we must have a clear understanding on strengths and weaknesses of Taguchi methodology together with a sound knowledge on the applicable system. This study provides some insights on Taguchi approach based on two case examples of one successful and the other unsuccessful. Eventually, this research aims to facilitate deeper understanding and right application of Taguchi methodology in industries.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.11
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• pp.970-975
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• 2002

We suggests an effective method to construct time-varying C-obstacles in the 3-dimensional configuration space (C-space) using free arc. The concept of free arc was defined mathematically and the procedure to find free arc in the case off-dimensional C-space was derived in [1]. We showed that time-varying C-obstacles can be constructed efficiently using this concept, and presented simulation results for two SCARA robot manipulators to verify the efficacy of the proposed approach. In this paper, extensions of this approach to the 3-dimensional C-space is introduced since nearly all industrial manipulators are reasonably treated ill the too or three dimensional C-space f3r collision avoidance problem The free arc concept is summarized briefly and the method to find lice arc in the 3-dimensional f-space is explained. To show that this approach enables us to solve a practical collision avoidance problem simulation results f3r two PUMA robot manipulators are presented.