• Proceedings of the KIEE Conference
• /
• 1999.11c
• /
• pp.643-645
• /
• 1999

In experiment, a real inverted pendulum system has state constraints and limited amplitude of input. These problems make it difficult to design a swing-up controller. To overcome these problems, we design a sliding mode controller considering physical behaviour of the inverted pendulum system. This sliding mode controller uses a switching control action to converge along a specified path derived from energy equation from a state around the path to desired states(standing position). And optimal control method is used to guarantee stability at unstable equilibrium position. The designed controller can be applied to all inverted pendulum systems regardless of the values of their parameters. Compared with previous existing controllers, it is simple and easy to tune. Experimental results are given to show the effectiveness of this controller.

• Proceedings of the KIEE Conference
• /
• 2000.07a
• /
• pp.75-79
• /
• 2000

This paper proposes the optimal placement with minimum set of Phasor Measurement Units (PMU's) using tabu search and makes an alternative plan to secure the robustness of the network with PMU's. The optimal PMU Placement (OPP) problem is generally expressed as a combinatorial optimization problem subjected to the observability constraints. Thus, it is necessary to make a use of an efficient method in solving the OPP problem. In this paper, a tabu search based approach to solve efficiently this OPP problem proposed. The observability of the network with PMU's is fragile at any single PMU contingency. To overcome the fragility, an alternative scheme that makes efficient use of the existing measurement system in power system state estimation proposed. The performance of the proposed approach and the alternative scheme is evaluated with IEEE sample systems.

• ETRI Journal
• /
• v.28 no.4
• /
• pp.517-520
• /
• 2006

In this letter, a new sharing mechanism, SRLG sharing, is proposed, which allows the links of the same shared risk link group (SRLG) in a primary light tree to share protections in WDM optical networks. In previous studies, how to share spare resources with SRLG constraints has not been studied in multicast optical networks. In this letter, considering SRLG sharing, we propose a novel algorithm -multicast with SRLG sharing (MSS)- to establish a protection light tree. Finally, the algorithm MSS and the algorithm multicast with no SRLG sharing (MNSS) are compared through a simulation to show that our new sharing scheme of SRLG sharing is more efficient than that of no SRLG sharing in terms of spare resource utilization and blocking probability.

• 제어로봇시스템학회:학술대회논문집
• /
• 1993.10a
• /
• pp.330-335
• /
• 1993

This paper presents an efficient solution for a class of forbidden state problems by introducing a cyclic timed controlled marked graphs (TCMG's), a special class of timed controlled Petri nets (TCPN's) as a model of a class of discrete event systems (DES's). The state feedback control is synthesized, which is maximally permissive while guaranteeing the forbidden states will be avoided. The practical applications or tire theoretical results for an automated guided vehicle (ACV) coordination problem in a flexible manufacturing facility is illustrated.

• Proceedings of the KSME Conference
• /
• 2001.11a
• /
• pp.667-672
• /
• 2001

An optimization approach is used to partition the field of view. A cost function is defined to represent the constraints on the solution, which is then mapped onto a two-dimensional Hopfield neural network for minimization. Each neuron in the network represents a possible match between a field of view and one or multiple objects. Partition is achieved by initializing each neuron that represents a possible match and then allowing the network to settle down into a stable state. The network uses the initial inputs and the compatibility measures between a field of view and one or multiple objects to find a stable state.

• Journal of Institute of Control, Robotics and Systems
• /
• v.5 no.6
• /
• pp.705-713
• /
• 1999

In this paper, we propose a new motion and force control methodology for constrained robots as an approach of hybrid discrete-continuous dynamical system. The hybrid dynamic system modeling of robotic manipulation tasks with constraints is presented, and the hybrid system control architecture for unconstrained and constrained motion system with parametric uncertainties is synthesized. The optimal reference stiffness of robot manipulator is generated by the hybrid automata as a discrete state system and the control behavior of constrained system which has poor modeling information and time-varying constraint function is improved by the constrained robots as a continuous state system. The performance of the proposed constrained motion control system is successfully evaluated via experimental studies to the constraint tasks.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2004.05a
• /
• pp.164-168
• /
• 2004

The vibration analysis of an axially moving membrane are investigated when the membrane has the two sets of in-plane boundary conditions, which are free and fixed constraints in the lateral direction. Since the in-plane stiffness is much higher than the out-of-plane stiffness, it is assumed during deriving the equations of motion that the in-plane motion is in a steady state. Under this assumption. the equation of out-of\ulcornerplane motion is derived, which is a linear partial differential equation influenced by the in-plane stress distributions. After discretizing the equation by using the Galerkin method, the natural frequencies and mode shapes are computed. In particular, we put a focus on analyzing the effects of the in-plane boundary conditions on the natural frequencies and mode shapes of the moving membrane.

• Asian-Australasian Journal of Animal Sciences
• /
• v.11 no.6
• /
• pp.774-780
• /
• 1998

This report includes an extensive bibliography of research articles investigating various facets of rearing neonatal piglets using liquid diets, and includes historical publications dating back to the 1940's. However, in order to provide concise and timely focus for application in modem swine production, only a selected number of recent findings are reviewed in detail. Collectively, the data presented illustrate that growth of piglets fed liquid diets can greatly exceed that of littermates fed dry diets and can even exceed growth rates of sow-reared controls (by up to 160%). The central questions that remain unanswered are: 1) Can this improved performance be obtained routinely and economically under applied farm conditions? and if so, 2) Does improved growth during the early-weaning period translate into improved net economic returns overall? Unfortunately, due to the current practical management constraints related to liquid-diet feeding (i.e., lack of an easy-to-manage feed delivery system), limited data are available which examine the efficacy of liquid-diet feeding under practical, commercial farm conditions.

• Journal of Mechanical Science and Technology
• /
• v.18 no.1
• /
• pp.122-131
• /
• 2004

A constraint equation-based control law design for large angle attitude maneuvers of flexible spacecraft is addressed in this paper The tip displacement of the flexible spacecraft model is prescribed in the form of a constraint equation. The controller design is attempted in the way that the constraint equation is satisfied throughout the maneuver. The constraint equation leads to a two-point boundary value problem which needs backward and forward solution techniques to satisfy terminal constraints. An observer-based tracking control law takes the constraint equation as the input to the dynamic observer. The observer state is used in conjunction with the state feedback control law to have the actual system follow the observer dynamics. The observer-based tracking control law eventually turns into a stabilized system with inherent nature of robustness and disturbance rejection in LQR type control laws.

• Proceedings of the Korean Information Science Society Conference
• /
• 2000.04a
• /
• pp.498-500
• /
• 2000

객체 지향 소프트웨어에 있어서, 테스팅의 중요성은 전통적인 소프트웨어의 개발에 있어서의 중요성과 크게 다르지 않다. 테스팅이 부적절하게 수행된 경우 프로그램의 버그를 성공적으로 검출 할 수 없으며, 소프트웨어 품질을 보장할 수 없다. 즉, 성공적인 소프트웨어를 위한 문제가 바로 테스팅이라 할 수 있다. 따라서 개발된 객체 지향 소프트웨어의 신뢰성을 향상시킬수 있는 객체 지향 테스팅 방법이 필요하다. 이 논문에서는 전통적인 소프트웨어 테스팅 기법과 객체 지향 특성을 결합하여 객체 지향 소프트웨어 테스팅을 위한 단위 설정을 위해 실시간 시스템에서 하나의 행위를 정의할 수 있는 객체 메소드의 결합에 대한 이벤트 그래프(Eent Gaph)와 제약적 메소드 시퀀스(M？ Sequence with Cnstraints)를 정의하고, 제약사항을 포함하는 이벤트 그래프와 메소드 시퀀스(sequence)를 정의하고, 제약사항을 포함하는 이벤트 그래프와 메소드 시퀀스(sequence)를 엘리베이터 시스템에 적용하여 객체 지향 실시간 시스템에 대한 객체 상태 행위 테스팅(object state behavior testing)을 통해 인트라 클래스 테스팅 및 인터 클래스 테스팅 기법을 제안한다.