A parametric insensitive H2 control design approach

H₂ and H_∞ control design methodologies are known to be efficient to deal with multivariable control problems. However, most of them do not take explicitly the parametric uncertainties into account. This paper proposes a low parametric sensitivity H₂ control design method as an alternative to µ‐synthesis or robust H₂ control design. In addition to the standard H₂ criterion, the H₂ norm of the parametric sensitivity function is introduced in order to improve the robustness of the resulting controller. Unfortunately, this problem is a difficult one. Its equivalence to structured feedback H₂ control problem will be shown. The underlying BMI will be solved by making use of an iterative LMI procedure. Two examples will illustrate the interest of the approach. Copyright © 2004 John Wiley & Sons, Ltd.     

Improving the Behavior of Intelligent Tutoring Agents with Data Mining

This article presents a novel framework for adapting the behavior of intelligent agents. The framework consists of an extended sequential pattern mining algorithm that, in combination with association rule discovery techniques, is used to extract temporal patterns and relationships from the behavior of human agents executing a procedural task. The proposed framework has been integrated within the CanadarmTutor, an intelligent tutoring agent aimed at helping students solve procedural problems that involve moving a robotic arm in a complex virtual environment. We present the results of an evaluation that demonstrates the benefits of this integration to agents acting in ill-defined domains.     

Platform‐independent profiling in a virtual execution environment

Virtual execution environments, such as the Java virtual machine, promote platform‐independent software development. However, when it comes to analyzing algorithm complexity and performance bottlenecks, available tools focus on platform‐specific metrics, such as the CPU time consumption on a particular system. Other drawbacks of many prevailing profiling tools are high overhead, significant measurement perturbation, as well as reduced portability of profiling tools, which are often implemented in platform‐dependent native code. This article presents a novel profiling approach, which is entirely based on program transformation techniques, in order to build a profiling data structure that provides calling‐context‐sensitive program execution statistics. We explore the use of platform‐independent profiling metrics in order to make the instrumentation entirely portable and to generate reproducible profiles. We implemented these ideas within a Java‐based profiling tool called JP. A significant novelty is that this tool achieves complete bytecode coverage by statically instrumenting the core runtime libraries and dynamically instrumenting the rest of the code. JP provides a small and flexible API to write customized profiling agents in pure Java, which are periodically activated to process the collected profiling information. Performance measurements point out that, despite the presence of dynamic instrumentation, JP causes significantly less overhead than a prevailing tool for the profiling of Java code. Copyright © 2008 John Wiley & Sons, Ltd.     

Utilisation of pectin coating to enhance spray-dry stability of pea protein-stabilised oil-in-water emulsions

In this study, development of pea (Pisum sativum) protein stabilised dry and reconstituted emulsions is presented. Dry emulsions were prepared by spray-drying liquid emulsions in a laboratory spray-dryer. The effect of drying on the physical stability of oil-in-water emulsions containing pea protein-coated and pea protein/pectin-coated oil droplets has been studied. Oil-in-water emulsions (5 wt.% Miglyol 812 N, 0.25 wt.% pea protein, 11% maltodextrin, pH 2.4) were prepared that contained 0 (primary emulsion) or 0.2 wt.% pectin (secondary emulsion). The emulsions were then subjected to spray-drying and reconstitution (pH 2.4). The stability of the emulsions to dry processing was then analysed using oil droplet size, microstructure, Zeta potential, and creaming measurements. Obtained results showed that the secondary emulsions had better stability to droplet aggregation after drying than primary emulsions. To interpret these results, we propound that pectin, an anionic polysaccharide, formed a less charged protective layer around the protein interfacial film surrounding the oil droplets that improved their stability to spray-drying mainly by increasing steric effects.     

Evaluation of the Particle Bonding for Aluminum Sample Produced by Spark Plasma Sintering

Journal of Materials Engineering and Performance - Spark plasma sintering (SPS) is a powder metallurgy process that sinters powder materials within a short time by simultaneous application...     

Feasibility study of utilization of commercially available polyurethane resins to develop non-biocidal wood preservation treatments

Evaluation of commercially available polyurethane resins used up to now for coating applications to develop non-biocidal wood preservation treatments has been conducted. A simple method of vacuum impregnation of these resins into beech wood (Fagus sylvatica L.) and pine wood (Pinus sylvestris L.) samples followed by varied curing processes at ambient temperature, 103, and 200 °C has been performed. Based on the analysis of weight percent gain before and after leaching, treatment resistance to leaching, anti-swelling efficiency, wettability and decay durability measured for treated and untreated blocks after leaching with the white-rot fungus Coriolus versicolor for both wood species and the brown-rot fungi Poria placenta and Gloeophyllum trabeum for pine wood, it can be concluded that such treatment can be considered as potential valuable non-biocidal treatments.     

Spatial reasoning about multimedia document for a profile based adaptation

The continuous evolution of smart devices has led to serious limitations in multimedia applications. The multimedia graphic design and animation and the increased use of rich and complex multimedia content on the web or other media have all created a need to diversify the accessibility of the content. Therefore several techniques are used today to design a universally accessible content. The main techniques that are still used to maintain accessibility is to create two parallel streams of design and development of the same content. Thus, the continuous evolution will certainly lead to create other streams. For this, the automatic reasoning on multimedia to allow a computer to modify the design according to different variables, devices capabilities, user status and context to provide personalized adapted content. In this paper, we propose an abstract document model called XMS short for XML Multimedia Specification; it describes the composition of an original multimedia document and can be extended to any document type. We present how we may use spatial information present in this document to adapt and modify the original document. We mainly focus on the spatial aspect of a web document, a combination of RCC8, qualitative distances, and directions are used to describe the layout of a set of objects. The level of granularity of the definition of the objects defines the level of details that will be processed by our PROLOG based inference system, simplified versions of algorithms from the inference system and how it works on the spatial dimension of the document are shown. In the end samples of how spatial relations manipulation algorithms work are illustrated.