• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.18 no.9
• /
• pp.1395-1403
• /
• 1993

Protocol conformance is crucial to inter-operability and cost effective computer communication. Given a protocol specification, the task of checking whether an inplementation conforms to the specification is called conformance testing. The efficiency and fault coverage of conformance testing are largely dependent on how test cases are chosen. Some states may have more one UIO sequence when the protocol is represented by FSM (Finite State Machine). The length of test sequence can be minimized if the optimal test sequences are chosen. In this paper, we construct the depth-tree to find the maximum overlapping among the test sequence. By using the resulting depth-tree, we generate the minimum-length test sequence. We show the example of the minimum-length test sequence obtained by using the resulting depth-tree.

• Journal of Institute of Control, Robotics and Systems
• /
• v.22 no.6
• /
• pp.411-416
• /
• 2016

This paper presents the design methodology of an unknown input observer for Lipschitz nonlinear systems with unknown inputs in the framework of convex optimization. We use an unknown input observer (UIO) to consider both nonlinearity and disturbance. By deriving a sufficient condition for exponential stability in the linear matrix inequality (LMI) form, existence of a stabilizing observer gain matrix of UIO will be assured by checking whether the quadratic stability margin of the error dynamics is greater than the Lipschitz constant or not. If quadratic stability margin is less than a Lipschitz constant, the coordinate transformation may be used to reduce the Lipschitz constant in the new coordinates. Furthermore, to reduce the maximum singular value of the observer gain matrix elements, an object function to minimize it will be optimally designed by modifying its magnitude so that amplification of sensor measurement noise is minimized via multi-objective optimization algorithm. The performance of UIO is compared to a nonlinear observer (Luenberger-like) with an application to a flexible joint robot system considering a change of load and disturbance. Finally, it is validated via simulations that the estimated angular position and velocity provide true values even in the presence of unknown inputs.

• Proceedings of the Korean Institute of Communication Sciences Conference
• /
• 1992.10a
• /
• pp.73-76
• /
• 1992

• 제어로봇시스템학회:학술대회논문집
• /
• 1993.10a
• /
• pp.250-255
• /
• 1993

In this paper, for detection and isolation of instrument and process faults related with steam generator(S/G) in nuclear power plant, two types of observers are designed based on the linearized dynamic model of S/G : a bank of Dedicated Observers (DOS) for instrument faults detection and a bank of Unknown Input Observers(UIO) for process faults detection. And then, they are combined to decide which one between the above two faults occurs. In principle, the failure in ith instrument(process) can be isolated by monitoring the error between the ith output and its estimation obtained from the ith DOS(UIO). It is shown via computer simulations that the present scheme is feasible in finding out the source of a fault.

• Electronics and Telecommunications Trends
• /
• v.14 no.2 s.56
• /
• pp.26-37
• /
• 1999

ATM 프로토콜 적합성 시험 생성 도구 개발을 프로토콜 개발 통합환경과 연계하여 개발한다. 즉 생성된 I/O FSM 중간모델을 대상으로 연구된 가장 짧은 길이의 시험 스위트(test suite)를 생성하는 알고리즘을 편리하고 용이하게 적용하기 위해 데이터 구조화 및 컴퓨터 내에서의 표현 등을 위한 초기화 작업기능을 SDL Editor & Simulator를 활용하여 확인한다. 그리고 ATS(Abstract Test Suite) 생성은 UIO 시퀀스를 결정하고, TUT와 도착상태의 UIO 시퀀스를 결합한 시험 subsequence 생성과 symmetric argumentation 과정을 거처 RCP(Rural Chinese Postman) Tour 생성 알고리즘 구현을 통해 완전 시험 스위트 생성도구를 개발하고, 프로토콜 검정기와 연계하여 통합된 환경에서 사용할 수 있도록 개발한다.

• International Journal of Control, Automation, and Systems
• /
• v.2 no.4
• /
• pp.530-535
• /
• 2004

This paper deals with the unknown input observer (UIO) design problem for a class of linear time-delay systems. A case in which the observer error can completely be decoupled from an unknown input is treated. Necessary and sufficient conditions for the existences of such observers are present. Based on Lyapunov stability theory, thedesign of the observer with internal delay is formulated in terms of linear matrix inequalities (LMI). The design of the observer without internal delay is turned into a stabilization problem in linear systems. Two design algorithms of UIO are proposed. The effect of the proposed approach is illustrated by two numerical examples.

• Proceedings of the KIEE Conference
• /
• 2000.07d
• /
• pp.2611-2613
• /
• 2000

This paper deals with a novel approach to unknown inputs observer(UIO) design for linear time-invariant dynamical systems using a fast Walsh transform and Walsh function's differential operation. Generally, UIO has a derivation of system outputs which is not available from the measurement directly. And it is an obstacle to estimate the unknown inputs properly when unexpected measurement noises are presented. Therefore, this paper propose an algebraic approach to eliminate such problems by using a Walsh function's differential operation.

• Proceedings of the KIEE Conference
• /
• 1996.07b
• /
• pp.1149-1151
• /
• 1996

In the last several years, considerable attention has been focused on the problem of designing observers for linear systems with unknown inputs. Since UIO(unknown inputs observer) has the derivative of the outputs, it is very sensitive to measurement noises. Therefore this note propose an algebraic approach to UIO design to alleviate the prescribed problems. Since the proposed method has simple form to estimate state and unknown input and robustness to sensor noise, we believe that it is very attractive in practice.

• The Transactions of the Korea Information Processing Society
• /
• v.4 no.2
• /
• pp.552-562
• /
• 1997

This paper proposes a formal method on confromance testing for INAP(AIN) test sequence generation by optimization technique.In order to implement and prove the dffectiveness of the proposed method,we specify the SRSM of INAP protocol SRF in SDL and generate I/O FSM by using our S/W tool. We generate an opti-mal test sequence by applying our method our method to this reference I/O FSM. We prove experimentally that the length of the generated test sequence by our method is more effective and shorter(i.e 32% improved)than the one geverated by UIO method,and estimate that The test coverage space of our test sequence is larger that of UIO method.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.23 no.5
• /
• pp.478-485
• /
• 2015

Availability of the climbing angle information is crucial for the intelligent vehicle system. However, the climbing angle information can't be measured with the sensor mounted on the vehicle. In this paper, climbing angle estimation system is proposed. First, longitudinal acceleration obtained from gyro-sensor is compared with the actual longitudinal acceleration of the vehicle. If the vehicle is in yawing motion, actual longitudinal acceleration can't be approximated from time derivative of wheel speed, because lateral velocity and yaw rate affect actual longitudinal acceleration. Wheel speed and yaw rate can be obtained from the sensors mounted on the vehicle, but lateral velocity can't be measured from the sensor. Therefore, lateral velocity is estimated using unknown input observer with nonlinear tire model. Simulation results show that the compensated results using lateral velocity and yaw rate show better performance than uncompensated results.