• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.11
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• pp.898-903
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• 2001

In this study, we investigated amounts, distributions and sizes of pores of multilayer piezoelectric transformer, and predicted heat emission property and electrical characteristics according to designs of internal electrode. Forming densities of device having MLC, fingered and full filled internal electrode structure were 4.73 g/㎤, 4.80 g/㎤, 4.82 g/㎤ and forming porosities were 17.3737%, 13.1475%, 12.6121%, respectively. And sintered densities of MLC structured, fingered and full filled devices were 7.76 g/㎤, 7.75 g/㎤, 7.84 g/㎤ and sintered porosities were 4.0967%, 2.7132%, 2.5317%, respectively. Therefore, we concluded that fingered and full fi1led internal electrode devices, expecially, fingered internal electrode devices had cost-effective effect and maximum poling effect due to higher sintered density and lower porosity than MLC structured device. Also we can predict that they have an effect on good heat emission and high output properties of multilayer piezoelectric transformer.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.5
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• pp.615-621
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• 1999

In this paper, we consider the robust stability of uncertain linear systems with time-delay in the time domain. The considered uncertainties are both the unstructured uncertainty which is only Known its norm bound and the structured uncertainty which is known its structured. Based on Lyapunov stability theorem and{{{{ { H}_{$\infty$ } }}}} theory known as Strictly Bounded Real Lemma (SBRL), we present new conditions that guarantee the robust stability of system. Also, we extend this to multiple time-varying delays systems and large-scale systems, respectively. Finally, we show the usefulness of our results by numerical examples.

• Journal of Ocean Engineering and Technology
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• v.13 no.1 s.31
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• pp.11-17
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• 1999

A three dimensional finite element generation code has been developed attaching simple blocks. Block can be either a quadrature or a cube depending on the dimension of a subject considered. Finite element serendipity basis functions are employed to map elements between the computational domain and the physical domain. Elements can be generated with wser defined progressive ratio for each block. For blocks to be connected properly, a block should have a consistent numbering scheme for vertices, side nodes, edges and surfaces. In addition the edge information such as the number of elements and the progressive ratio for each direction should also be checked for interfaces to have unique node numbers. Having done so, user can add blocks with little worry about the orientation of blocks, Since the present the present code has been written by a Visual Basic language, it can be developed easily for a user interactive manner under a Windows environment.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.511-516
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• 2000

In order to not only perform as a extreme model under the severe operating condition but also acquire more diverse and advanced control capability utilizing high compliance, active vibration control of a flexible 2-link robot manipulator are investigated. Multi variable-structured frequency shaped optimal sliding mode is proposed for the flexible robot manipulator like control system, whose control variables, an angular motion of joint and vibration of flexible link, have to be controlled simultaneously by one control torque at a driving joint. The control system is divided into two subsystems, a control input related subsystem and an added subsystem. The proposed sliding mode, composed of multi control variables, makes optimized relation between subsystems and a individual control input, thus, the sliding mode controller can compensate whole dynamics of each subsystems simultaneously. And the possibility and effectiveness are verified by vibration control of a manipulator having two flexible links. Simulation and experiment results show that the proposed control scheme achieves the purpose effectively.

• Industrial Engineering and Management Systems
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• v.1 no.1
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• pp.58-63
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• 2002

Recently a new multi-attribute analysis method is one of the evident areas of important points in the decision support system analysis. The area of decision support system may be broken into three primary area: idea generation, multi-attribute structured analysis method, and the integration of the results of analysis. This research developed an internet/intranet-based solution builder for a three-step decision support system in the view of 1) brainstorming for the idea generation, 2) analytic hierarchy process as a multi-attribute structured analysis method and 3) aggregating logic model to integrate the results of individual analysis. A computer program is developed and demonstrated in internet/intranet-based decision problem. This solution builder provides decision makers a good tool for remote group decision making.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.38 no.11
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• pp.950-957
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• 1989

We have shown how unstructured modeling was used to derive a general stability condition in Part 1. In Part 2, we focus on the particular dynamics (structured modiling) of the robot manipulator and environment. Using rigid body dynamics, the stability condition for the direct drive robots has been achieved in terms of the Jacobian and robot tracking controller. Combining the structured and unstructured modeling, a stability condition for a particular application can be obtained. This approach has been used to analyze compliant motion on the University of Minnesota robot using a feedforward torque controller. We have obtained a stability condition for this application. Through both simulation and experiment, the sufficiency of this condition has been demonstrated. For a sufficient stability condition, recall that if the condition is satified, then the stability is guaranteed` however, if the condition is violated, no conclusion can be made.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.1
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• pp.31-35
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• 1999

In this paper, we consider the robust pole assignment and the upper bound of quadratic cost function for the linear systems with time-varying uncertainy. The considered uncertainties are both the norm bounded unstructured case and the structured case that has the matrix polytope type uncertain structure. We derve conditions that guarantee the robust pole assignment inside a disk in the L.H.P. and the robust stability. Also, we derive the upper bound of quadratic cost for thil pole assigned systems. Finally, we show the usefulness of our results by an example.

• The Transactions of the Korea Information Processing Society
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• v.6 no.5
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• pp.1212-1218
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• 1999

This paper proposes a new multipath interconnection network(MIN) structure for improving performance which uses widely in the design of multiprocessing, ATM system and VOD server. For improving performance such as passthrough ratio and packet latency, it proposes new routing method which routes one of the collided packets into the i+1-th switching stage of the adding Banyan MIN network when it occurred collision at the i-th switching stage of the basic MIN again when they collide each other. The new improved performance MIN network has been compared with MBSF, TBSF and PBSF structured MIN network from the viewpoint of passthrough ratio and the number of switching stage vs. passthrough ratio. It is shown to improve a performance and to be a simple structure which reducing the number of switching stage of adding MIN in comparison with other structured MIN including TBSF.

• Annual Conference of KIPS
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• 2002.04b
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• pp.1013-1016
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• 2002

제어 시스템에 사용되는 흐름 제어 언어로는 IL(Instruction List), ST(Structured Text), FBD(Function Block Diagram), SFC(Sequential Function Chart), LD (Ladder Diagram)가 있다. 일반적으로 제어 시스템에 탑재하여 사용하는 언어는 상기 언어 중 두 종류 이하의 특정 언어로 제한되어 있다. 이러한 제약을 보완하기 위해, 모든 흐름 제어 언어를 통합 분석할 수 있는 통합 분석기가 필요하다. 본 논문에서는 흐름 제어 언어의 통합 분석 처리가 가능하도록 그래픽 표현의 FBD 를 문자 표현의 EST(Extended Structured Text)로 변형하는 규칙과 문자 표현의 EST 를 IL 로 변형하는 규칙을 제시한다. 언어간의 변형 과정에서 FBD 를 ST 로 표현할 수 없는 부분을 EST 로 정의한다. 또한 본 논문에서 제안된 EST 를 기반으로 통합 분석기의 구조를 제시한다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.457-460
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• 1999

The effects of electrical positive stress on n-channel LDD and offset structured poly-Si TFT\`s have been systematically investigated in order to analyze the transfer curve\`s shift mechanism. It has been found that the LDD and offset regions behave as a series resistance that reduce the electric field near drain. Hot carrier effects are reduced because of these results. After electrical stress transfer curve’s shift and variation of the off-current are dependent upon the offset length rather than offset region’s doping concentration. Variation of the subthreshold slope is dependent upon offset region’s doping concentration as well as offset length.