Robust ℋ︁∞ filtering for uncertain differential linear repetitive processes

The unique characteristic of a repetitive process is a series of sweeps or passes through a set of dynamics defined over a finite duration known as the pass length. At the end of each pass, the process is reset and the next time through the output, or pass profile, produced on the previous pass acts as a forcing function on, and hence contributes to, the dynamics of the new pass profile. They are hence a class of systems where a variable must be expressed in terms of two directions of information propagation (from pass‐to‐pass and along a pass, respectively) where the dynamics over the finite pass length are described by a matrix linear differential equation and from pass to pass by a discrete updating structure. This means that filtering/estimation theory/algorithms for, in particular, 2D discrete linear systems is not applicable. In this paper, we solve a general robust filtering problem with a view towards use in many applications where such an action will be required. Copyright © 2007 John Wiley & Sons, Ltd.     

Preparation of Strontium Titanate Thin Films by the Hydrothermal-Electrochemical Method in a Solution Flow System

SrTiO₃ thin films have been prepared on titanium substrates using strontium acetate solutions in newly constructed flow-system equipment by the hydrothermal-electrochemical method. The synthesis parameters (temperature of 120°-200°C and flow rate of 1-40 mL/min) allow fabrication of dense, single-phase films with grain sizes in the range of 80-340 nm by controlling nucleation and/or growth rates. The flow can be closed, enabling easy recycling of the solutions used. This processing route may serve as an inexpensive and environmentally friendly way of fabrication of single-phase SrTiO₃ thin films as well as functionally graded ferroelectric materials.     

Recent advances in visible light-driven water oxidation and reduction in suspension systems

In order to solve the shortage of sustainable energy and the related concern about combustion of fossil fuels, converting the most abundant solar energy into chemical fuels becomes one of the most promising choices to provide the everlasting and environmentally friendly energy vector along with the minimum impact on environment. Among the methods of converting solar energy into chemical fuels, there is a significant interest in the renewable hydrogen production by photocatalysts from abundant water under visible light irradiation. Therefore, the development of efficient photocatalysts for water reduction and oxidation in a suspension system is the footstone for the development of solar energy conversion. In this review, the fundamental theory of photocatalysis and key factors affecting photocatalysis will be introduced first. Then the new materials development covering inorganic materials (oxides, nitrides and sulfides), carbon-based photocatalysts, and semiconductor-coordination compound photocatalysts developed over the past 10?years will be addressed with discussion about dominating factors in the photochemical process. This review would provide a comprehensive reference to exploring the efficient and novel materials working for the solar energy conversion to affordable and sustainable fuels. Finally, the perspective of the technology is also discussed.     

Evolving strategy for a probabilistic game of imperfect information using genetic programming

We provide the complete record of methodology that let us evolve BrilliAnt, the winner of the Ant Wars contest. Ant Wars contestants are virtual ants collecting food on a grid board in the presence of a competing ant. BrilliAnt has been evolved through a competitive one-population coevolution using genetic programming and fitnessless selection. In this paper, we detail the evolutionary setup that lead to BrilliAnt’s emergence, assess its direct and indirect human-competitiveness, and describe the behavioral patterns observed in its strategy.

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Analyzing complex FTMS simulations: a case study in high-level visualization of ion motions

Current practice in particle visualization renders particle position data directly onto the screen as points or glyphs. Using a camera placed at a fixed position, particle motions can be visualized by rendering trajectories or by animations. Applying such direct techniques to large, time dependent particle data sets often results in cluttered images in which the dynamic properties of the underlying system are difficult to interpret. In this case study we take an alternative approach to the visualization of ion motions. Instead of rendering ion position data directly, we first extract meaningful motion information from the ion position data and then map this information onto geometric primitives. Our goal is to produce high-level visualizations that reflect the physicists' way of thinking about ion dynamics. Parameterized geometric icons are defined to encode motion information of clusters of related ions. In addition, a parameterized camera control mechanism is used to analyze relative instead of only absolute ion motions. We apply the techniques to simulations of Fourier transform mass spectrometry (FTMS) experiments. The data produced by such simulations can amount to 5 10(4) ions and 10(5) timesteps. This paper discusses the requirements, design and informal evaluation of the implemented system.     

Reasoning about temporal properties of rational play

This article is about defining a suitable logic for expressing classical game theoretical notions. We define an extension of alternating-time temporal logic (ATL) that enables us to express various rationality assumptions of intelligent agents. Our proposal, the logic ATLP (ATL with plausibility) allows us to specify sets of rational strategy profiles in the object language, and reason about agents’ play if only these strategy profiles were allowed. For example, we may assume the agents to play only Nash equilibria, Pareto-optimal profiles or undominated strategies, and ask about the resulting behaviour (and outcomes) under such an assumption. The logic also gives rise to generalized versions of classical solution concepts through characterizing patterns of payoffs by suitably parameterized formulae of ATLP. We investigate the complexity of model checking ATLP for several classes of formulae: It ranges from $\Delta_{\mathbf{3}}^{\mathbf{P}}$ to PSPACE in the general case and from $\Delta_{\mathbf{3}}^{\mathbf{P}}$ to $\Delta_{\mathbf{4}}^{\mathbf{P}}$ for the most interesting subclasses, and roughly corresponds to solving extensive games with imperfect information.     

Experimental and computational analysis of large amplitude vibrations of spatial viscoelastic beams

Summary This paper describes the usefulness of the rigid finite element method to analyse high amplitude vibrations of viscoelastic beams. It also presents an experimental verification of the method. The trajectory of a chosen point during free vibrations is investigated. A good compatibility of the calculation and experimental results is achieved.