Higher order eigensensitivity analysis of damped systems with repeated eigenvalues

A simplified method for the computation of first-, second- and higher-order derivatives of eigenvalues and eigenvectors associated with repeated eigenvalues is presented. Adjacent eigenvectors and orthonormal conditions are used to compose an algebraic equation. The algebraic equation which is developed can be used to compute derivatives of eigenvalues and eigenvectors simultaneously. Since the coefficient matrix in the proposed algebraic equation is non-singular, symmetric and based on N-space, it is numerically stable and very efficient compared to previous methods. To verify the efficiency of the proposed method, the finite element model of the cantilever beam and a mechanical system in the case of a non-proportionally damped system are considered.     

On the Computational Complexity of Consumer Decision Rules

A consumer entering a new bookstore can face more than 250,000alternatives. The efficiency of compensatory and noncompensatory decisionrulesfor finding a preferred item depends on the efficiency of their associatedinformation operators. At best, item-by-item information operators lead tolinear computational complexity; set information operators, on the other hand,can lead to constant complexity. We perform an experiment demonstrating thatsubjects are approximately rational in selecting between sublinear and linearrules. Many markets are organized by attributes that enable consumers toemploya set-selection-by-aspect rule using set information operations. In cyberspacedecision rules are encoded as decision aids.     

Implementation of a TMO‐structured real‐time airplane‐landing simulator on a distributed computing environment

In real‐time simulation, the simulated system should display the same (or very close) timing behavior as the target system. The simulation accuracy is increased as the simulation time unit is decreased. Although there are several models for such systems, the TMO model is particularly appropriate due to its natural support for real‐time distributed object‐oriented programming. This paper discusses the results of the implementation of a real‐time airplane‐landing simulator on a distributed computing environment using the TMO model. Copyright © 2004 John Wiley & Sons, Ltd.     

A nonlinear minimization approach to multiobjective and structured controls for discrete‐time systems

In this paper, a nonlinear minimization approach is proposed for multiobjective and structured controls for discrete‐time systems. The problem of finding multiobjective and structured controls for discrete‐time systems is represented as a quadratic matrix inequality problem. It is shown that the problem is reduced to a nonlinear minimization problem that has a concave objective function and linear matrix inequality constraints. An algorithm for the nonlinear minimization problem is proposed, which is easily implemented with existing semidefinite programming algorithms. The validity of the proposed algorithm is illustrated by comparisons with existing methods. In addition, applications of this work are demonstrated via numerical examples. Copyright © 2004 John Wiley & Sons, Ltd.     

Optimal Representative Blocks for the Efficient Tracking of a Moving Object

Optimal representative blocks are proposed for an efficient tracking of a moving object and it is verified experimentally by using a mobile robot with a pan‐tilt camera. The key idea comes from the fact that when the image size of a moving object is shrunk in an image frame according to the distance between the camera of mobile robot and the moving object, the tracking performance of a moving object can be improved by shrinking the size of representative blocks according to the object image size. Motion estimation using edge detection (ED) and block‐matching algorithm (BMA) are often used in the case of moving object tracking by vision sensors. However, these methods often miss the real‐time vision data since these schemes suffer from the heavy computational load. To overcome this problem and to improve the tracking performance, the optimal representative block that can reduce a lot of data to be computed is defined and optimized by changing the size of the representative block according to the size of object in the image frame. The proposed algorithm is verified experimentally by using a mobile robot with a two degree‐of‐freedom active camera. © 2004 Wiley Periodicals, Inc.     

Kinematic optimal design of a paramill: A multi‐SP device

In this paper, a manipulability analysis of a new parallel‐type rolling mill, named “paramill,” in its conceptual design stage is investigated. The paramill considered uses two Stewart platforms (SPs) in opposite directions for the generation of 6 degree‐of‐freedom motions of individual work‐rolls. The objective of this new approach is to pursue an integrated control of the strip thickness, strip shape, pair‐crossing angle, uniform wear of the rolls, and tension of the strip. The forward/inverse kinematics problems are formulated. Two main kinematic parameters, the size of the base and the acute angle made by two neighboring joints for a given size of the work‐roll, have been determined in the way that the force and moment transmission from the actuators to the work‐rolls is maximized. © 2004 Wiley Periodicals, Inc.     

Effects of gendered character representation on person perception and informational social influence in computer-mediated communication

Two experiments examined (a) if the gender of a randomly assigned character would affect individuals' inferences about an anonymous partner in computer-mediated communication (CMC) and (b) how the gender inference would moderate informational social influence. In Experiment 1, participants played a trivia game on a gender-biased topic (sports vs. fashion) with their ostensible partner via computer, represented by a gender-marked cartoon character. The results showed that both men and women, despite the arbitrary nature of character assignment, categorized the partner according to the character's gender. However, the effects of the gender inference on conformity were moderated by the topic and the participant's gender. First, when the topic matched the participant's gender, there was no character effect. Second, whereas women used “expertise heuristics”, exhibiting greater conformity to the male-charactered than female-charactered partner on a masculine topic, men displayed greater conformity to the male-charactered than female-charactered partner on a feminine topic, suggesting male resistance to female influence. Using a gender-neutral topic, Experiment 2 confirmed the explanations. Although the character triggered gender-stereotypical perception of the partner, when the gender was not diagnostic of expertise, the character's gender did not affect women's conformity behavior while men nonetheless showed greater conformity to the male-charactered partner.     

Delay-dependent robust H∞ control for uncertain systems with a state-delay

A robust H_∞ control for uncertain linear systems with a state-delay is described. Systems with norm-bounded parameter uncertainties are considered and linear memoryless state feedback controllers are obtained. Firstly, a delay-dependent bounded real lemma for systems with a state-delay is presented in terms of linear matrix inequalities (LMIs). By taking a new Lyapunov-Krasovsii functional, neither model transformation nor bounding for cross terms is required to obtain delay-dependent results. Secondly, based on the bounded real lemma obtained, delay-dependent condition for the existence of robust H_∞ control is presented in terms of nonlinear matrix inequalities. In order to solve these nonlinear matrix inequalities, an iterative algorithm involving convex optimization is proposed. Numerical examples show that the proposed methods are much less conservative than existing results.     

ISE tuning rule revisited

The integral square error (ISE) method is applied to approximate the internal model control (IMC) system by the PID control system. Simulations show that the proposed method to design PID controllers can relieve some disadvantages of the original ISE method and IMC-based PID controller design methods.     

3D television: Developing a multi‐modal multi‐viewer TV system of the future

Abstract— Under the European Union funded Advanced Three‐dimensional Television System Technologies (ATTEST) project, De Montfort University (DMU) is developing a 3D display system targeted specifically at domestic television applications. This system uses a modified transmissive LCD panel together with novel backlighting and optics to project multiple viewing regions, or exit pupils, into the viewing space. These exit pupils are located in space using a head tracker. The display accommodates multiple viewers simultaneously and imposes no physical constraints, such as special eyewear. Viewers may move freely over a “typical” room‐sized area. The design of the backlighting facilitates many other display regimes beyond the “standard” 3DTV mode in which each viewer sees the same image pair.