Iterative performance improvement of fuzzy control systems for three tank systems

This paper suggests the performance improvement of fuzzy control systems (FCSs) for three tank systems using iterative feedback tuning (IFT). The stable design of Takagi–Sugeno–Kang fuzzy controllers is guaranteed by means of a stability theorem based on LaSalle’s global invariant set theorem formulated for a class of multi input-multi output (MIMO) nonlinear processes. An IFT algorithm characterized by setting the step size to guarantee the FCS stability is proposed. The theoretical approaches are applied in a case study that deals with the IFT-based stable design of fuzzy controllers dedicated to the level control of a cylindrical three tank system as a representative MIMO system. A set of experimental results for a laboratory setup illustrates the performance improvement.     

An adaptive compressed MPEG-2 video watermarking scheme

Digital watermarking is becoming more and more important for protecting the authenticity of multimedia objects as they become easier to copy, exchange, and modify. Several watermarking schemes have been proposed in recent years, but most of them deal with still images, only some being extended over to the temporal domain for video watermarking. But again most of those approaches are applied to uncompressed video processing domain. In the subject paper, a new compressed video watermarking procedure is proposed. The developed method embeds several binary images, decomposed from a single watermark image, into different scenes of a video sequence. The spatial spread spectrum watermark is embedded directly into the compressed bit streams by modifying discrete cosine transform (DCT) coefficients. In order to embed the watermark with minimum loss in image fidelity, a visual mask based on local image characteristics is incorporated. Extensive experimental simulations demonstrate that the proposed watermarking scheme is substantially more effective and robust against spatial attacks such as scaling, rotation, frame averaging, and filtering, besides temporal attacks like frame dropping and temporal shifting.     

Robotic sensor agents: a new generation of intelligent agents for complex environment monitoring

Monitoring environment parameters is a complex task of great importance in many areas, such as the natural living environment; homeland security; industrial or laboratory hazardous environments (biologically, radioactively, or chemically contaminated); polluted/toxic natural environments; water treatment plants; nuclear stations; war zones; or remote, difficult-to-reach environments, such as the deep space or underwater. This article will discuss a new generation of intelligent, autonomous, wireless robotic sensor agents (RSAs) for complex environment monitoring. Shown in this article is the architecture of an RSA system under development in our laboratory at the University of Ottawa (see Petriu et al., p14-19, May 2002). Monitoring is done by continuously collecting sensory data from stationary and mobile RSAs deployed in the field.     

Parity bit signature in response data compaction and built-in self-testing of VLSI circuits with nonexhaustive test sets

The design of efficient time compression support hardware for built-in self-testing (BIST) is of great importance in the design and manufacture of VLSI circuits. The test data outputs in BIST are ultimately compressed by time compaction hardware, commonly called a response analyzer, into signatures. Several output response compaction techniques to aid in the synthesis of such support circuits already exist in literature, and parity bit signature coupled with exhaustive testing is already well known to have certain very desirable properties in this context. This paper reports new time compaction techniques utilizing the concept of parity bit signature that facilitates implementing such support circuits using nonexhaustive or compact test sets, with the primary objective of minimizing the storage requirements for the circuit under test (CUT) while maintaining the fault coverage information as best as possible.     

A study of the robustness of pseudorandom binary-array-basedsurface characterization

In this paper me report on aspects of the use of color-coded pseudorandom binary arrays (PRBA's) to model three-dimensional scenes. We evaluate the accuracy and the robustness of the pattern recognition phase in the process. Emphasis is on the added value of the use of PRBA's as a tool to make the image processing robust and highly noise insensitive     

Software bottlenecking in client-server systems and rendezvousnetworks

Software bottlenecks are performance constraints caused by slow execution of a software task, in typical client-server systems a client task must wait in a blocked state for the server task to respond to its requests, so a saturated server will slow down all its clients. A rendezvous network generalizes this relationship to multiple layers of servers with send-and-wait interactions (rendezvous), a two-phase model of task behavior, and to a unified model for hardware and software contention. Software bottlenecks have different symptoms, different behavior when the system is altered, and a different cure from the conventional bottlenecks seen in queueing network models of computer systems, caused by hardware limits. The differences are due to the “push-back” effect of the rendezvous, which spreads the saturation of a server to its clients. The paper describes software bottlenecks by examples, gives a definition, shows how they can be located and alleviated, and gives a method for estimating the performance benefit to be obtained. Ultimately, if all the software bottlenecks can be removed, the performance limit will be due to a conventional hardware bottleneck     

Influence of reference domain unstability upon the precision of random reference quantizer with uniformly distributed auxiliary source

The paper approaches the effect of domain unstability in random reference in the case of Random Reference Quantizer (RRQ) with uniformly distributed reference and a constant input signal. It is mainly concerned with emphasizing the influence of the finite sample number upon the final error of the mean value of the RRQ output.     

Aliasing-free compaction revisited

The design of space-efficient support hardware for built-in self-testing is of immense significance in the synthesis of present day very large-scale integration circuits and systems, particularly in the context of design paradigm shift from system-on-board to system-on-chip (SOC). The authors revisit the general problem of designing zero-aliasing (or aliasing-free) space compression hardware in relation to embedded cores-based SOC for single stuck-line faults in particular, extending the well-known concepts of conventional switching theory and of incompatibility relation to generate maximal compatibility classes utilising graph theory concepts, based on optimal generalised sequence mergeability, as developed by them in earlier works. The authors briefly present the mathematical basis of selection criteria for merger of an optimal number of outputs of the module under test for realising maximum compaction ratio in the design, along with extensive simulation results on ISCAS 85 combinational and ISCAS 89 full-scan sequential benchmark circuits, with simulation programs ATALANTA, FSIM and COMPACTEST.     

A Prototype for 3-D Hand Tracking and Posture Estimation

In this paper, we explain our experience in designing a prototype for 3-D hand tracking and dynamic gesture recognition. Our objective is to be able to continuously visually track the hand in a general background and to be able to recognize dynamic gestures in real time. The constraints and the conditions for our system to justify our approach are generic nonrestricted environment and generic nonspecific application. Our prototype has undergone several stages—from simulation to three different cycles of development and testing. We also present a road map for future development to reach the final goal.