• Smart Structures and Systems
• /
• 제15권4호
• /
• pp.1041-1062
• /
• 2015

In this paper a method of finding optimal positions for piezoelectric actuators and sensors on different structures is presented. The genetic algorithm and multi-objective genetic algorithm are selected for optimization and $H_{\infty}$ norm is defined as a cost function for the optimization process. To optimize the placement concerning the selected modes simultaneously, the multi-objective genetic algorithm is used. The optimization is investigated for two different structures: a cantilever beam and a simply supported plate. Vibrating structures are controlled in a closed loop with feedback gains, which are obtained using optimal LQ control strategy. Finally, output of a structure with optimized placement is compared with the output of the structure with an arbitrary, non-optimal placement of piezoelectric patches.

• Journal of Information Processing Systems
• /
• 제19권4호
• /
• pp.439-449
• /
• 2023

This paper deals with a resource efficient artificial intelligence (AI) service architecture for multi-channel video streams. As an AI service, we consider the object detection model, which is the most representative for video applications. Since most object detection models are basically designed for a single channel video stream, the utilization of the additional resource for multi-channel video stream processing is inevitable. Therefore, we propose a resource efficient AI service framework, which can be associated with various AI service models. Our framework is designed based on the modular architecture, which consists of adaptive frame control (AFC) Manager, multiplexer (MUX), adaptive channel selector (ACS), and YOLO interface units. In order to run only a single YOLO process without regard to the number of channels, we propose a novel approach efficiently dealing with multi-channel input streams. Through the experiment, it is shown that the framework is capable of performing object detection service with minimum resource utilization even in the circumstance of multi-channel streams. In addition, each service can be guaranteed within a deadline.

• 한국결정성장학회:학술대회논문집
• /
• 한국결정성장학회 1996년도 제11차 KACG 학술발표회 Crystalline Particle Symposium (CPS)
• /
• pp.285-309
• /
• 1996

Non oxide ceramics such as nitrides of transition metals have shown significant potential for future economic impact, in diverse applications in ceramic, aerospace and electronic industries, as refractory products, abrasives and cutting tools, aircraft components, and semi-conductor substrates amid others. Combustion synthesis has become an attractive alternative to the conventional furnace technology to produce these materials cheaply, faster and at a higher level of purity. However he process os highly exothermic and manifests complex dynamics due to its strongly non-linear nature. In order to develop an understanding of this process and to study the effect of operational parameters on the final outcome, numerical modeling is necessary, which would generated essential knowledge to help scale-up the process. the model is based on a system of parabolic-hyperbolic partial differential equations representing the heat, mass and momentum conservation relations. The model also takes into account structural change due to sintering and volumetric expansion, and their effect on the transport properties of the system. The solutions of these equations exhibit steep moving spatial gradients in the form of reaction fronts, propagating in space with variable velocity, which gives rise to varying time scales. To cope with the possibility of extremely abrupt changes in the values of the solution over very short distances, adaptive mesh techniques can be applied to resolve the high activity regions by ordering grid points in appropriate places. To avoid a control volume formulation of the solution of partial differential equations, a simple orthogonal, adaptive-mesh technique is employed. This involves separate adaptation in the x and y directions. Through simple analysis and numerical examples, the adaptive mesh is shown to give significant increase in accuracy in the computations.

• 한국해양공학회지
• /
• 제12권3호통권29호
• /
• pp.96-102
• /
• 1998

This paper presents to create a SAC(Sectional Area Curve) using an ANFIS(Adaptive-Network-based Fuzzy Inference System). First, it defines SACs of parent ships by using a B-spline approximation and a genetic algorithm and accumulates a database about SAC's control points. Second, it learns an ANFIS from parent ship data, which are related with principal dimensions and SAC's control points. This process is to model an ANFIS for SAC inferreice. When an ANFIS modeling is completed, we can determine a SAC through an ANFIS inferring.

• 한국지능시스템학회논문지
• /
• 제11권5호
• /
• pp.395-399
• /
• 2001

이 논문은 학습을 통해 관측 데이터로부터 퍼지 추론 모듈을 생성할 수 있는 적응 능력을 갖는 모듈화 퍼지추론 시스템을 제안한다. 제안한 시스템은 TS 퍼지모델과 모듈화 신경회로망의 구조적 유사성을 기초로 한다. 학습과정은 새로운 퍼지추론 모듈의 생성과 모듈 파라미터의 갱신으로 구성된다. 퍼지추론 모듈은 국부모델망과 퍼지 게이팅망으로 구성된다. 제안한 시스템의 파라미터들은 표준 LMS 알고리즘을 이용하여 최적화된다. 제안한 시스템의 성능은 비선형 동적 시스템 적응제어에의 응용을 통해서 입증된다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2006년도 심포지엄 논문집 정보 및 제어부문
• /
• pp.210-212
• /
• 2006

This paper presents Hybrid PI(HBPI) controller of IPMSM drive using fuzzy adaptive mechanism control. In general, PI controller in computer numerically controlled machine process fixed gain. They may perform well under some operating conditions, but not all. To increase the robustness, fixed gain PI controller, HBPI controller proposes a new method based self tuning PI controller. HBPI controller is developed to minimize overshoot and settling time following sudden parameter changes such as speed, load torque, inertia, rotor resistance and self inductance. The results on a speed controller of IPMSM are presented to show the effectiveness of the proposed gain tuner. And this controller is better than the fixed gains one in terms of robustness, even under great variations of operating conditions and load disturbance.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1990년도 하계학술대회 논문집
• /
• pp.510-513
• /
• 1990

This paper describes the procedures for pre-tuning and re-tuning of the PI controller to specifications on patterns of output response. The key ideas of the proposed adaptive scheme are as follows. The relay feedback is adopted first for pre-tuning and the adaptive algorithms by the pattern recognition are introduced for re-tuning procedure to retune the gains whenever control conditions are changed. The proposed scheme was applied to the experimental laboratory process, heat exchanger.

• 대한전자공학회논문지
• /
• 제24권1호
• /
• pp.52-59
• /
• 1987

A new on-line estimation algorithm for a time varying time delay is proposed. This algorithm is based on the concept of minimization of prediction error. As only the parameters directly related to the poles and zeros of the process are estimated in the algorithm, persistently exciting condition for the convergence of parameters can be less restrictive. Under some assumptions which is necessary in adaptive control, it is shown that this algorithm estimates time varying time delay accurately. In view of computational burden, this algorithm needs far less amount of calculations than other methods. The larger the time delay is, the more effective this algorithm is . Computer simulation shows good properties of the algorithm. This algorithm can be used effectively in adaptive control of large dead time processes.

• 한국지능시스템학회:학술대회논문집
• /
• 한국퍼지및지능시스템학회 2007년도 춘계학술대회 학술발표 논문집 제17권 제1호
• /
• pp.421-428
• /
• 2007

본 논문은 퍼지 계층분석법을 이용하여 교통신호의 교차로망에서의 적합성에 대해서 논의한다. 교차로망에서의 교통신호는 현시, 주기등이 단일 교차로망의 교통신호 대안이라고 한다면 교차로 망에서의 교통신호 대안은 앞에 있는 교차로의 통행차량수와 지체차량수등 2개 이상의 교차로망의 상대적인 대안을 제시하여야 하므로 단일교차로의 교통신호 대안과는 다른 모습을 띠고 있다. 교통신호체계는 고정신호체계, 최적신호체계, 퍼지응용신호체계를 구별하여 응용단계가 높은 신호체계가 적합성이 톨음을 퍼지계층분석법을 이용하여 밝히고 이를 이용 새로운 체계의 교통신호 체계도 재시한다.

• 한국인터넷방송통신학회논문지
• /
• 제13권5호
• /
• pp.1-8
• /
• 2013

본 논문에서는, 차량 섀시 제어시스템 중 ACC(Adaptive Cruise Control)와 LKS(Lane Keeping System)를 통합하여 차량용 OS인 OSEK OS 기반으로 구현하고 실험을 통하여 그 성능을 분석한다. 최근 자동차의 안전성을 향상시키기 위해 능동 안전 및 운전자 지원 시스템이 논의 되고 있다. 그 중 차량의 종방향에 대한 가감속 제어를 수행하는 ACC와 차량이 차선을 유지할 수 있도록 보조해주는 LKS를 통합하여 차량 내 제어시스템을 구현한다. 구현한 제어시스템은 차량용 소프트웨어의 재사용성과 안전성 및 응용 소프트웨어의 하드웨어 의존성 제거 등을 목표로 표준 제안된 OSEK/VDX를 적용한다. OSEK/VDX에서 지원하는 OSEK OS를 기반으로 재설계한 제어시스템은 실시간 태스크 관리와 인터럽트 처리 및 공유자원 관리가 가능하다. EILS(ECU-In-the-Loop Simulation) 수행 결과에 의해 OSEK OS 기반의 ACC/LKS 통합제어기와 기존 일체형 펌웨어로 구현한 ACC/LKS 통합제어기가 대등함을 입증한다.