An original approximate method for estimating the invariant probability distribution of a large class of multi-dimensional nonlinear stochastic oscillators

This paper proposes an original method for obtaining analytical approximations of the invariant probability density function of multi-dimensional Hamiltonian dissipative dynamic systems under Gaussian white noise excitations, with linear non-conservative parts and nonlinear conservative parts. The method is based on an exact result and a heuristic argument. Its pertinence is attested by numerical tests.     

A universal design resource for rich Internet applications based on design patterns

Rich Internet applications have removed most of the constraints of Web 1.0 while giving users more responsiveness and advanced browsing and interaction experiences. These new horizons, however, raise many challenges for people with disabilities or using limited hardware and software technologies, whose risk to be excluded from the benefits deriving from advanced web applications. To address this problem, WCAG 2.0 guidelines have been released as the newest World Wide Web Consortium recommendation for accessible web content, and WAI-ARIA is a candidate recommendation which provides reference specifications for accessible rich Internet applications. However, both specifications contain a huge amount of information that often discourages most web designers from dealing with accessibility issues. Moreover, guidelines are suitable and usually adopted to judge a design solution a posteriori, but they do not suggest how to face a design problem constructively. This paper proposes a design pattern language for accessibility. The language can be regarded as a universal design resource for helping web designers create accessible rich Internet applications compliant with the most recent standards. Knowledge representation through design patterns reflects the problem-solving approach usually followed by software and web designers, while pattern organization in a structured language aims to guide web designers throughout the design process. The language has been implemented as an accessible rich Internet application itself, thus allowing designers with disabilities to participate in web design. In order to evaluate the design pattern language, a three-step process was carried out including: (1) a heuristic analysis with a group of human–computer interaction experts, (2) a survey study with a group of web designers, and (3) a validation on the field with two designers who have been requested to apply the language in real design cases.     

Rule-based tools for the configuration of ambient intelligence systems: a comparative user study

Multimedia Tools and Applications - This paper describes a 63-participant user study that compares two widely known systems supporting end users in creating trigger-action rules for the Internet of...     

A probabilistic approach for estimating the behavior of railway tracks

Railway engineering is confronted with problems due to degradation of the rail network that requires important and costly maintenance work. However, because of lack of knowledge on the geometrical and mechanical parameters of the track, it is difficult to optimize maintenance management. In this context, this paper presents a new methodology to analyze the behavior of railway tracks. It combines new diagnostic devices which permit to obtain an important amount of data and thus to make statistics on the geometric and mechanical parameters and a non-intrusive stochastic approach which can be coupled with any mechanical model. Numerical results show the possibilities of this methodology for parametric studies (influence of the distribution and of the correlation of the parameters...). In the future this approach will give important informations to railway managers to optimize maintenance operations.     

Toward overcoming culture, skill and situation hurdles in Human-Computer Interaction

This paper proposes a new effective strategy for designing and implementing interactive systems overcoming culture, skill and situation hurdles in Human-Computer Interaction (HCI). The strategy to identify and reduce these hurdles is developed in the framework of a methodology based on a recently introduced model of HCI, and exploits the technological innovations of XML (Extensible Markup Language). HCI is modelled as a cyclic process in which the user and the interactive system communicate by materializing and interpreting a sequence of messages. The interaction process is formalized by specifying both the physical message appearance and the computational aspect of the interaction. This formalization allows the adoption of notation traditionally adopted by users in their workplaces as the starting point of the interactive system design. In this way, the human–system interaction language takes into account the users’ culture. Moreover, the methodology permits user representatives to build a hierarchy of systems progressively adapted to users’ situations, skills and habits, according to the work organization in the domain considered. The strategy is proved to be effective by describing how to implement it using BANCO (Browsing Adaptive Network for Changing user Operativity), a feasibility prototype based on XML, which allows the hierarchy implementation and system adaptations. Several examples from an environmental case under study are used throughout the paper to illustrate the methodology and the effectiveness of the technology adopted. Published online: 4 June 2002     

Further exploration of typical and maximum performance criteria: Definitional issues, prediction, and White-Black differences.

Addresses differences between typical and maximum performance criteria with a threefold purpose. First, the growing recognition that it is important to distinguish between typical and maximum performance criteria is examined. Second, clarification of definitional and measurement issues are addressed. Third, results of an empirical study are offered to contribute to the new knowledge base regarding typical and maximum performance criteria. The study investigates differences in validities of cognitive ability predictor measures against supermarket cashier typical and maximum performance criteria reflecting speed and accuracy. White–Black mean score differences on typical and maximum performance criteria are also examined. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relations between measures of typical and maximum job performance.

In this study we proposed that understanding of interrelations among criterion measures can be improved by differentiating between measures of typical and maximum job performance. We offered defining characteristics of typical and maximum performance measures and requirements for a fair examination of relations between the two. Typical and maximum performance measures of the speed and accuracy with which supermarket cashiers process items were obtained from two large samples (Ns?=?635 and 735) of cashiers from 12 supermarket chains. Relatively low correlations between typical and maximum performance measures were found. We discuss the implications of these findings for the use of maximum performance measures as criteria in the validation of selection systems and for the understanding of the impact of ability and motivation on job performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Highly efficient full-vectorial 3-D BPM modeling of fiber to planarwaveguide couplers

The behavior of a fiber-slab coupler used as a polarization and wavelength tunable filter is studied both experimentally and theoretically. The theoretical model is based on a three-dimensional (3-D) fully vectorial beam propagation method (BPM), whose main features concern its high efficiency from the point of view of memory and central processing unit (CPU) requirements. The device characteristics have been measured and the results of the comparisons among experimental and theoretical two-dimensional (2-D) and 3-D numerical modeling are reported and discussed. They show a very good agreement In the 3-D case where field polarization, coupling terms and z-variant structures are taken into account     

Inhibitory effect of suramin in rat models of angiogenesis in vitro and in vivo

The aim of the present study was to test the ability of the chemotherapeutic agent suramin to inhibit angiogenesis in experimental models in vitro and in vivo. In the culture of rat aortic rings on fibronectin, suramin dose-dependently inhibited vascular cell growth, achieving the maximal effect (mean - 88% versus controls, P < 0.05) at 400 microg/ml. Image analysis showed that suramin could inhibit microvessel sprouting in fibrin from rat aortic rings as evaluated by the ratio between the cellular area and the mean gray value of the sample (sprouting index); suramin at 50 microg/ml significantly reduced the sprouting index from the control value of 0.35+/-0.04 to 0.14+/-0.02 mm2/gray level (P < 0.05). Likewise, the area occupied by cells was 19.2+/-1.8 mm2 as compared with 41.8+/-4.2 mm2 in controls (P < 0.05). In the rat model of neovascularization induced in the cornea by chemical injury, suramin at 1.6 mg/eye per day reduced the length of blood vessels (0.7+/-0.1 mm as compared with 1.5+/-0.1 mm in controls, P < 0.05). In the same model the ratio between the area of blood vessels and the total area of the cornea (area fraction score) was decreased by suramin from 0.19+/-0.02 in controls to 0.03+/-0.003 (P < 0.05). Suramin given i.p. at 30 mg/ kg per day markedly inhibited the neovascularization induced in the rat mesentery by compound 48/80 or conditioned medium from cells secreting the angiogenic protein fibroblast growth factor-3 (FGF-3). The area fraction score in control rats treated with compound 48/80 was 0.31+/-0.03, and this was reduced to 0.07+/-0.01 by suramin (P < 0.05). After i.p. administration of FGF-3 the area fraction score was reduced by suramin from 0.29+/-0.03 to 0.05+/-0.01 (P < 0.05). These results provide evidence that suramin exerts inhibitory effects on angiogenesis in both in vitro and in vivo models.