• 대한전자공학회논문지SD
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• 제43권6호
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• pp.23-29
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• 2006

본 논문에서는 Quadratic Programming(QP)을 이용한 효과적인 광역배치 기법을 제안한다. QP를 이용한 배치 기법의 단점인 셀 밀집 문제를 해결하기 위해 추가적인 힘(additional force)과 Grid Pre-warping 기법을 사용하였다 추가적인 힘은 밀집도에 기반한 값으로 적절한 힘을 구하기 위해 새로운 밀집도 함수를 고안하였다. Grid Pre-warping은 셀 좌표 사이의 상대적인 순서에 따라 셀들을 전체 영역에 재배치하는 기법이다. 새로운 밀집도 함수를 통해 구해진 추가적인 힘과 Pre-warping 기법을 반복적으로 적용하여 셀들이 효과적으로 분산된 광역배치를 얻었다. 이렇게 얻어진 배치를 "middle-down" 방식의 배치기인 Mongre의 초기배치로 적용하여 최종 상세배치 결과를 얻었다 제안하는 기법을 적용한 실험결과, FM 기법을 이용한 광역배치에 비해 향상된 결과를 보였으며, 우수한 배치기로 알려진 FengShui, Dragon과도 비교할만한 결과를 얻었다.

• The Journal of Advanced Prosthodontics
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• 제7권1호
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• pp.76-84
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• 2015

This article reviews the topic of how to identify and develop a removable partial denture (RPD) path of placement, and provides a literature review of the concept of the RPD path of placement, also known as the path of insertion. An optimal RPD path of placement, guided by mutually parallel guide planes, ensures that the RPD flanges fit intimately over edentulous ridge structures and that the framework fits intimately with guide plane surfaces, which prevents food collecting empty spaces between the intaglio surface of the framework and intraoral surfaces, and ensures that RPD clasps engage adequate numbers of tooth undercuts to ensure RPD retention. The article covers topics such as the causes of obstructions to RPD intra-oral seating, the causes of food collecting empty spaces that may exist around an RPD, and how to identify if a guide plane is parallel with the projected RPD path of placement. The article presents a method of using a surgical operating microscope, or high magnification (6-8x or greater) binocular surgical loupes telescopes, combined with co-axial illumination, to identify a preliminary path of placement for an arch. This preliminary path of placement concept may help to guide a dentist or a dental laboratory technician when surveying a master cast of the arch to develop an RPD path of placement, or in verifying that intra-oral contouring has aligned teeth surfaces optimally with the RPD path of placement. In dentistry, a well-fitting RPD reduces long-term periodontal or structural damage to abutment teeth.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국내학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
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• pp.452-456
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• 1988

A PID controller must need not only good servo response but also little operation of a control valve. We suggest a direct pole-placement PID self-tuning algorithm using the structure of derivative-of-output controller and Bezout identity. This algorithm can much reduce the change of output of controller and well follow the desired trajectory.

• 대한전자공학회논문지SD
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• 제42권12호
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• pp.61-70
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• 2005

본 논문에서는 "middle-down" 접근법에 기반한 기존의 표준 셀 배치기인 하이브리드 배치기$^{[25]}$의 단점을 보완한 효율적인 광역배치 알고리즘을 제안한다. hMETIS(클러스터링을 이용한 다단계 하이퍼그래프 분할기법)에 사용된 기법과 RBLS(Relaxation Based Local Search) 기법의 적절한 조합을 통해 기존 하이브리드 배치기의 광역배치 기능을 향상시킨다. hMETIS를 통한 분할기법을 "top-down" 방식으로 적용하고, 각 단계에서 RBLS를 사용하여 광역배치를 점진적으로 개선해 나가는 제안된 기법은 초기 배치에 크게 영향을 받는 기존 방법의 문제점을 해결하고, 실행 속도를 개선하면서도 배치의 질을 떨어뜨리지 않는 효과적인 기법이다. 제안한 알고리즘을 통해 구현된 개선된 배치기는 기존의 하이브리드 배치기나 FengShui와 같은 우수한 툴과 비교할 때 뒤지지 않는 성능을 보인다. 특별히 기존의 하이브리드 배치기에 비해 실행 속도 면에서 평균 5배 정도의 개선을 보였고, 큰 회로에 대해선 배선길이도 줄어드는 향상된 결과를 보였다.

• Smart Structures and Systems
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• 제5권3호
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• pp.241-260
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• 2009

Shape control of flexible structures using piezoelectric materials has attracted much attention due to its wide applications in controllable systems such as space and aeronautical engineering. The major work in the field is to find a best control voltage or an optimal placement of the piezoelectric actuators in order to actuate the structure shape as close as possible to the desired one. The current research focus on the investigation of static shape control of intelligent shells using spatially distributed piezoelectric curve beam actuators. The finite element formulation of the piezoelectric model is briefly described. The piezoelectric curve beam element is then integrated into a collocated host shell element by using nodal displacement constraint equations. The linear least square method (LLSM) is employed to get the optimum voltage distributions in the control system so that the desired structure shape can be well matched. Furthermore, to find the optimal placement of the piezoelectric curve beam actuators, a genetic algorithm (GA) is introduced in the computation model as well as the consideration of the different objective functions. Numerical results are given to demonstrate the validity of the theoretical model and numerical algorithm developed.

• Journal of Korean Neurosurgical Society
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• 제51권1호
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• pp.66-70
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• 2012

Thoracic pedicle screw fixation techniques are still controversial for thoracic deformities because of possible complications including neurologic deficit. Methods to aid the surgeon in appropriate screw placement have included the use of intraoperative fluoroscopy and/or radiography as well as image-guided techniques. We describe our technique for free hand pedicle screw placement in the thoracic spine without any radiographic guidance and present the results of pedicle screw placement analyzed by computed tomographic scan in two human cadavers. This free hand technique of thoracic pedicle screw placement performed in a step-wise, consistent, and compulsive manner is an accurate, reliable, and safe method of insertion to treat a variety of spinal disorders, including spinal deformity.

• Smart Structures and Systems
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• 제31권3호
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• pp.247-257
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• 2023

In structural health monitoring of large-scale structures, optimal sensor placement plays an important role because of the high cost of sensors and their supporting instruments, as well as the burden of data transmission and storage. In this study, a vibration sensor placement algorithm based on deep reinforcement learning (DRL) is proposed, which can effectively solve non-convex, high-dimensional, and discrete combinatorial sensor placement optimization problems. An objective function is constructed to estimate the quality of a specific vibration sensor placement scheme according to the modal assurance criterion (MAC). Using this objective function, a DRL-based algorithm is presented to determine the optimal vibration sensor placement scheme. Subsequently, we transform the sensor optimal placement process into a Markov decision process and employ a DRL-based optimization algorithm to maximize the objective function for optimal sensor placement. To illustrate the applicability of the proposed method, two examples are presented: a 10-story braced frame and a sea-crossing bridge model. A comparison study is also performed with a genetic algorithm and particle swarm algorithm. The proposed DRL-based algorithm can effectively solve the discrete combinatorial optimization problem for vibration sensor placements and can produce superior performance compared with the other two existing methods.

• 경영과학
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• 제10권2호
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• pp.145-161
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• 1993

Human Resource Management (HRM) performs numerous activities in organizations including employee recruitment, selection, placement, job analysis, training and development, and labor relations. POSCO (Pohang Steel Company) has concerned with employee management related to job placement and analysis among these activities because of the problems of over-complexity of placement precedures for the variety of recruits, the frequency of selection, a large amount of job descriptions / specifications, and their changes. This study, as a phase of developing the entire HRM systems in the organization, briefly summarizes the preliminary information related and describes an implementation of expert system as a means for effective job placement based on the principle of right-person-in-right-place with identifying aptitudes and personalities of employees. Thus, a new approach for developing a job description/specification using a formal specification language like Z is also proposed. The result of this study will cultivate the performance of personnel, prevent conflicts between labor and management, promote overall productivity of organization, as well as helpfully verify job analysis.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 추계학술대회 논문집 학회본부
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• pp.327-331
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• 1989

This paper concerned about a study on the direct pole placement PID self-tuning controller design for Robot manipulator control system. The method of a direct pole placement self-tuning PID control for a DC motor of robot manipulator tracks a reference velocity in spite of the parameters uncertainties in nonminimum phase system. In this scheme, the parameters of controller are estimated by the recursive least square(RLS) identification algorithm, the pole placement method and diophantine equation. A series of simulation in which minimum phase system and nonminimum phase system are subjected to a pattern of system parameter changes is presented to show some of the features of the proposed control algorithm. The proposed control algorithm which shown are effective for the practical application, and experiments of DC motor speed control for Robot manipulator by a microcomputer IRH-PC/AT are performed and the results are well suited.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.754-758
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• 1996

This paper presents a new approach to the design of self-tuning adaptive control system that is robust to the changing dynamic configuration as well as to the load variation factors using Digital signal processors for robot manipulators. TMS320C50 is used in implementing real-time adaptive control algorithms to provide advanced performance for robot manipulator, In this paper, an adaptive control scheme is proposed in order to design the pole-placement self-tuning controller which can reject the offset due to any load disturbance without a detailed description of robot dynamics. Parameters of discrete-time difference model are estimated by the recursive least-square identification algorithm, and controller parameters we determined by the pole-placement method. Performance of self-tuning adaptive controller is illusrated by the simulation and experiment for a SCARA robot.