2,312 publications from this institution
This paper presents the stability analysis of a fuzzy proportional-derivative (PD) controller. The proposed fuzzy PD controller has the same simple linear structure as the conventional PD controller in the proportional and derivative parts, but the two fuzzy control gains are nonlinear functions of the input error signals and they both have self-tuning control capability. The fuzzy PD controller has the same performance as the conventional PD controller for linear processes, yet improves the control capability for nonlinear and uncertain processes. We employ the "small gain theorem" to analyze the bounded-input/bounded-output stability of a general nonlinear fuzzy PD control system, deriving a simple and realistic sufficient condition for the stability of the system.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>
The classical Kalman filtering technique is extended to interval linear systems with the same statistical assumptions on noise, for which the classical technique is no longer applicable. Necessary interval analysis, particularly the notion of interval expectation, is reviewed and introduced. The interval Kalman filter (IKF) is then derived, which has the same structure as the classical algorithm, using no additional analysis or computation from such as H/sup /spl infin//-mathematics. A suboptimal IKF is suggested next, for the purpose of real-time implementation. Finally, computer simulations are shown to compare the new interval Kalman filtering algorithm with the classical Kalman filtering scheme and some other existing robust Kalman filtering methods.
This paper studies t-norms on the space $\mathbf{L}$ of all normal and convex fuzzy truth values. We first prove that the only non-convolution form type-2 t-norm constructed by Wu et al. satisfies the distributivity law for meet-convolution and show that t-norm in the sense of Walker and Walker is strictly stronger than t$_{r}$-norm on $\mathbf{L}$, which is strictly stronger than t-norm on $\mathbf{L}$. Furthermore, we characterize some restrictive axioms of t$_{r}$-norms for convolution operations on $\mathbf{L}$ and obtain some necessary conditions for t$_{r}$-(co)norm convolution operations on $\mathbf{L}$ .
Many digital services, such as pay-TV, confidential video conferencing, medical and military imaging systems, require reliable security in storage and transmission of digital images/videos.As the rapid progress of Internet in the digital world today, the security of digital images/videos has become more and more important.In recent years, more and more consumer electronic services and devices, such as mobile phones and PDA (personal digital assistant), have also started to provide additional functions of saving and exchanging multimedia messages.The prevalence of multimedia technology in our society has promoted digital images and videos to play a more significant role than the traditional dull texts, which demands a serious protection of users' privacy.To fulfill such security and privacy needs in various applications, encryption of images and videos is very important to frustrate malicious attacks from unauthorized parties.From early 1990s, many efforts have been made to investigate specific solutions to image/video encryption.Due to the tight relationship between chaos theory and cryptography, chaotic cryptography has also been extended to design image and video encryption schemes.This chapter focuses on different image/video encryption algorithms based on chaos, and clarifies some experiences, lessons and principles of using chaos to design such encryption schemes.To start, a comprehensive discussion on the state-of-the-art of image/video encryption will first be given as background and motivation for the discussion of the chapter.The organization of this chapter is as follows.In Sec.4.2, some preliminaries on image/video encryption are first given.Sec.4.3 is a comprehensive review on today's image/video encryption technology without using chaos theory.Chaos-based image and video encryption schemes are then surveyed in Sec.4.4.Some experiences, lessons and principles drawn from existing chaos-based image/video encryption algorithms are commented and discussed in Sec.4.5.The last section concludes the chapter. Image/
This paper describes a fuzzy proportional-integral (PI) controller and its application in boilers control for power plants. First, the fuzzy PI controller is briefly described. Then, some real data simulations for boilers control in power plants are shown to demonstrate its advantages for controlling the temperature of the generator and the boiler feed tank level over the conventional PI controllers that are used in power industries today.
This brief proposes a neuro-adaptive method for the unsolved problem of cooperative tracking rendezvous of nonholonomic mobile robots (NMRs) subject to uncertain and unmodelled dynamics. A hierarchical cooperative control framework is proposed, which consists of a novel distributed estimator along with local neuro-adaptive tracking controllers. Rigorous stability analysis as well as simulation experiments illustrate the proposed method.
No abstract is provided for this article.
No abstract is provided for this article.
The paper proposes a digital circuit design for the logistic-map module used in chaotic stream ciphers, analyzes the factors that may affect the output of the sequences, and develops a calculation method for estimating the output sequential correlative peak interval. With the respective tests using different initial values, the values of parameter u and the computational precisions, extensive experiments have been carried out. A formula for calculating correlative peak interval is proposed. Moreover, the relationships among precision, parameter u and correlative peak interval is provided. To ensure the security of the plaintext which is encrypted by the output sequence of the logistic-map, a proper precision could be chosen according to the formula. It provides a theoretic basis for the actual application of the chaos cryptology. The basic theory and methods have a significant implication on the statistical analysis and practical applications of the digital chaotic sequences. A diagram that presents the relationship among precision, parameter u and correlative peak interval has been generated for analysis.
This paper introduces a chaotic system in the spherical coordinates which, when expressed in the Cartesian coordinate system, has a chaotic attractor located in an impassable sphere like a bird in the cage. It also has a coexisting attractor outside that sphere. Basic dynamical properties of this system are investigated and its FPGA realization is demonstrated.
Uncertain delayed genetic regulatory networks are investigated from an adaptive filtering approach based on an adaptive synchronization setting.For an unknown regulatory network with time delay and uncertain noise disturbance, several adaptive laws are derived to ensure the stochastic stability of the error states between the unknown network and the estimated model.The novelty lies in the fact that the designed adaptive laws are independent of the unknown system states and parameters, requiring only the output and structure of the underlying network.A representative simulation example is given to verify the effectiveness of the theoretical results.
