A covert attention P300-based brain-computer interface: Geospell

The Farwell and Donchin P300 speller interface is one of the most widely used brain-computer interface (BCI) paradigms for writing text. Recent studies have shown that the recognition accuracy of the P300 speller decreases significantly when eye movement is impaired. This report introduces the GeoSpell interface (Geometric Speller), which implements a stimulation framework for a P300-based BCI that has been optimised for operation in covert visual attention. We compared the Geospell with the P300 speller interface under overt attention conditions with regard to effectiveness, efficiency and user satisfaction. Ten healthy subjects participated in the study. The performance of the GeoSpell interface in covert attention was comparable with that of the P300 speller in overt attention. As expected, the effectiveness of the spelling decreased with the new interface in covert attention. The NASA task load index (TLX) for workload assessment did not differ significantly between the two modalities. PRACTITIONER SUMMARY: This study introduces and evaluates a gaze-independent, P300-based brain-computer interface, the efficacy and user satisfaction of which were comparable with those off the classical P300 speller. Despite a decrease in effectiveness due to the use of covert attention, the performance of the GeoSpell far exceeded the threshold of accuracy with regard to effective spelling.     

Load forecasting framework of electricity consumptions for an Intelligent Energy Management System in the user-side

This work presents an electricity consumption-forecasting framework configured automatically and based on an Adaptative Neural Network Inference System (ANFIS). This framework is aimed to be implemented in industrial plants, such as automotive factories, with the objective of giving support to an Intelligent Energy Management System (IEMS). The forecasting purpose is to support the decision-making (i.e. scheduling workdays, on-off production lines, shift power loads to avoid load peaks, etc.) to optimize and improve economical, environmental and electrical key performance indicators. The base structure algorithm, the ANFIS algorithm, was configured by means of a Multi Objective Genetic Algorithm (MOGA), with the aim of getting an automatic-configuration system modelling. This system was implemented in an independent section of an automotive factory, which was selected for the high randomness of its main loads. The time resolution for forecasting was the quarter hour. Under these challenging conditions, the autonomous configuration, system learning and prognosis were tested with success.     

Anomaly Detection Using Real-Valued Negative Selection

This paper describes a real-valued representation for the negative selection algorithm and its applications to anomaly detection. In many anomaly detection applications, only positive (normal) samples are available for training purpose. However, conventional classification algorithms need samples for all classes (e.g. normal and abnormal) during the training phase. This approach uses only normal samples to generate abnormal samples, which are used as input to a classification algorithm. This hybrid approach is compared against an anomaly detection technique that uses self-organizing maps to cluster the normal data sets (samples). Experiments are performed with different data sets and some results are reported.     

An efficient technique for implementing an image-compression neural algorithm on concurrent multiprocessor architectures

The paper describes a parallel implementation of a neural algorithm performing vector quantization for very low bit-rate video compression on toroidal-mesh multiprocessor systems. The neural model considered is a plastic version of the Neural Gas algorithm, whose features are suitable for implementations on toroidal mesh topologies. The architecture adopted, and the data-allocation strategy, enhance the method's scaling properties and remarkable efficiency. The parallel approach is supported by a theoretical analysis of the efficiency of the overall structure. Experimental results on a significant testbed and the fit between predicted and measured values confirm the validity of the parallel approach.     

Transitions in Presence of Short Laser Pulses

Abstract

Accurate numerical calculations are carried out to investigate the validity of the two-state approximation in the case of resonant interactions between electromagnetic radiation and atoms. Short pulses are considered and the presence of the atomic spectrum is modelled by introducing a third, non-resonant, state. We show that the harmonics of the pulse profile may play a significant role in the dynamics of the process and may cause energy non-conserving transitions between the atomic states.     

A three dimensional exact equation for the turbulent dissipation rate of Generalised Newtonian Fluids

The flow of non-Newtonian fluids is of interest in many biological and industrial applications, including nanofluids. Most of the papers of the literature on turbulent non-Newtonian fluids focused the attention on viscoelastic fluids. In order to make accurate and low cost prediction of turbulent inelastic non-Newtonian fluids, a RANS Generalised Newtonian Fluid (GNF) turbulence model, based on the exact equations for the turbulent variables, is required. In a previous paper of the same authors the exact equations for the turbulent kinetic energy and the dissipation rate have been derived in a two-dimensional (2D) domain, through the introduction of an apparent viscosity equation. The aim of the present paper is to extend the approach to a three-dimensional (3D) domain, giving the full mathematical demonstration of the exact equations.     

Thermal–economic–environmental analysis and multi-objective optimization of an internal-reforming solid oxide fuel cell–gas turbine hybrid system

In this article, an internal-reforming solid oxide fuel cell–gas turbine (IRSOFC–GT) hybrid system is modeled and analyzed from thermal (energy and exergy), economic, and environmental points of view. The model is validated using available data in the literature. Utilizing the genetic algorithm optimization technique, multi-objective optimization of modeled system is carried out and the optimal values of system design parameters are obtained. In the multi-objective optimization procedure, the exergy efficiency and the total cost rate of the system (including the capital and maintenance costs, operational cost (fuel cost), and social cost of air pollution for CO, NO_x, and CO₂) are considered as objective functions. A sensitivity analysis is also performed in order to study the effect of variations of the fuel unit cost on the Pareto optimal solutions and their corresponding design parameters. The optimization results indicate that the final optimum design chosen from the Pareto front results in exergy efficiency of 65.60% while it leads to total cost of 3.28 million US$ year⁻¹. It is also demonstrated that the payback time of the chosen design is 6.14 years.     

Optimal control with constrained total variance for Markov jump linear systems with multiplicative noises

We consider in this paper the stochastic optimal control problem of discrete-time linear systems subject to Markov jumps and multiplicative noises (MJLS-mn for short). Our objective is to present an optimal policy for the problem of maximising the system's total expected output over a finite-time horizon while restricting the weighted sum of its variance to a pre-specified upper-bound value. We obtain explicit conditions for the existence of an optimal control law for this problem as well as an algorithm for obtaining it, extending previous results in the literature. The paper is concluded by applying our results to a portfolio selection problem subject to regime switching.     

Synthesis and characterization of conjugated polymers for the obtainment of conductive patterns through laser tracing

This article describes the preparation of thin films of conjugated polymers which can enhance their specific electrical conductivity by several orders of magnitude by changing their state from insulating to conducting materials. The examined polymers, i.e., a polyacetylenic and a polythiophenic derivative, are functionalized with thioalkylic side chains and are soluble in common organic solvents from which they lead to thick homogeneous films. The films can be deposited on different substrates, either rigid or flexible, and can be easily exposed to laser radiation to make them conductive. The process is irreversible, and the final conductivity is stable over time, even in the presence of high temperatures (up to 180 °C), moisture, and air. The high stability of treated samples, easy polymer synthesis and quick and inexpensive suitably tailored laser tracing procedure make these materials very promising for applications in organic electronics and in the development of new electronic circuitry.     

Effect of sugar, citric acid and egg white type on the microstructural and mechanical properties of meringues

Meringues are characterized by a predominant air phase and their overall quality is intimately related with microstructure. The formation of meringues microstructure relies on the capacity of egg white (EW) proteins to form voluminous and stable foams and it is ultimately related with the chemical properties of proteins and with the addition of ingredients such as sugars, salts, acids and surfactants.The study aimed at assessing the influence of sugar/EW ratio, citric acid and EW type on the microstructural and mechanical properties of meringues. Meringues prepared with different sugar/EW, citric acid level and different EW type were subjected to microstructural analysis by X-ray microtomography and to mechanical assessment by compression tests.Results demonstrate the ability of X-ray microtomography to reconstruct the 3D microstructure of meringues allowing the measurement of porosity, size, shape and distribution of pores. Citric acid, sugar concentration and EW type play a fundamental role on meringues microstructural parameters and mechanical properties. Low sugar/EW ratios as well as increasing citric acid levels increase the air phase and result in a softer texture of meringues. Moreover, low sugar/EW ratios and increasing citric acid in the meringue result in a reduction of pore size and also influence the shape of pores. Meringues microstructural and mechanical properties are affected by the EW quality: fresh and pasteurized EWs and EWs stored at refrigerated temperatures scored the highest structural and mechanical performances, while powdered and frozen EWs and albumens from old eggs showed the worst results. Not only the balance among ingredients but also the choice of raw materials can strongly affect the final quality of meringues.