Rigorous Numerical Approach to Isolation in Dynamical Systems on the Example of the Kuramoto-Sivashinsky Equation

This paper describes a method of rigorous verification of an isolating neighborhood based on computer assisted computations. As an application we study the Kuramoto-Sivashinsky equation. The result of the computer assisted proof was directly used in [9] to prove the existence of heteroclinic solutions of the Kuramoto-Sivashinsky equation.     

Analysis of fluid flow and energy transport in Czochralski's process

In this paper the conjugate fluid flow and energy transport problem (involving conduction-convection-radiation heat transfer) resulting from the Czochralski crystal growth process is analysed. The solidifying material is treated as a pure and semitransparent substance with material properties depending neither on temperature nor on the wavelength. The solution of the problem is obtained iteratively using two computer codes: FLUENT, a commercial CFD package, and BEM-based in-house code capable of analysing the radiative heat transfer in the entire computational domain.Obtained results not only show velocity field and temperature distribution within the bodies under consideration but also demonstrate the influence of thermal radiation on these quantities.     

Uniqueness in Shape from Shading Revisited

We analyse the problem of representing solutions of first-orderpartial differential equations in terms of complete integrals and envelopes. In this context, we revisit the uniqueness results alreadyexisting in the shape-from-shading literature that concern eikonalequations corresponding to the images of a Lambertian hemi-sphere and aLambertian plane. We show that the approach adopted by Brooks in [2, 3] isincomplete and subsequently re-establish its uniqueness claims.     

Distributed OSGi built over message‐oriented middleware

This paper describes key aspects of remote service invocation in federations of OSGi containers. It refers to the OSGi Remote Service Admin specification and describes its efficient implementation over message‐oriented middleware. Scalability problems of several different approaches to implementation are identified, and a solution in a form of innovative Remote Service Admin model extension is proposed. The extension, named On‐demand Remote Service Admin, is analyzed and validated in the context of a motivating scenario. Validation includes performance and scalability evaluation, which confirms that all assumed requirements have been satisfied by the constructed prototype. Finally, the presented research is compared with related works. Copyright © 2011 John Wiley & Sons, Ltd.     

On decentralised control of non-linear interconnected systems

The asymptotic stabilisation problem of a class of large-scale interconnected systems is considered, where the non-linear interconnections between subsystems satisfy quadratic constraints that are functions of the whole system's state vector. A decentralised combined observer-controller compensator is proposed and analysed, where the subsystems’ state vectors are estimated using local sliding mode observers. The closed-loop system driven by the proposed decentralised compensator is guaranteed to be asymptotically stable subject to two conditions that are easily verifiable. Simulation results illustrate the effectiveness of the proposed decentralised combined observer-controller compensator.     

Adaptive Control of the Electro‐Hydraulic Servo‐System with External Disturbances

The paper deals with the structure of the adaptive control electro‐hydraulic servo‐system (EHSS) with external load disturbances, practical verification of the identification, and control algorithms. The electro‐hydraulic servo system composed of a servo‐cylinder controlled with a servo‐valve is discussed. It is a strongly nonlinear object with parameters changing over time. Adaptive adjuster parameters were determined by means of current identification resulting in the parametric model. Identification was conducted on the basis of measurement of the controlling size and regulated size objects. The identified model of the object was applied to carry out the on‐line synthesis of the proportional–integral–derivative (PID) controller. The selected problems connected with obtaining the algorithm of adaptive control are presented. The computer program for implementing the algorithm with numerical simulation and identification of the control physical model object were calculated. The aim of the research was to examine the effectiveness of the adaptive control method in an electro‐hydraulic servo system, both theoretically and experimentally.     

Fundamentals of modelling concurrency using discrete relational structures

We consider relational structures such that is a set and are two binary relations on . For a number of different classes of structures we show that any structure can be represented as the intersection of its maximal extensions. Such a property – called extension completeness – can be seen as a generalisation of Szpilrajn's theorem which states that each partial order is the intersection of its total order extensions. When can be interpreted as causality and as ‘weak’ causality we obtain a model of concurrent histories generalising that based on causal partial orders. Received 1 February 1994 / 6 May 1996