A flexible approach to evaluating soft conditions with unequal preferences in fuzzy databases

A flexible model for evaluating soft query with unequal preferences in fuzzy databases is proposed. We assume that conditions with unequal preferences have an exclusive meaning like in the request “find a holiday accommodation such that big apartments are preferred to high rating hotels.” In this case it is assumed that the aggregator of the soft conditions is an implicit OR. Conversely, conditions with unequal importance have an inclusive meaning, like in the query “find a house to rent that is cheap (most important), big (important), new (fairly important).” In this case the implicit aggregator is an AND. What we propose in this article is to model preferences as modifiers of the semantics of the evaluation function of the conditions. Because the soft conditions are aggregated by an OR, the more a soft condition is preferred, the more its evaluation function tolerates a greater undersatisfaction of the soft condition. The proposed approach is formalized by considering two alternative semantics of the evaluation function: the first semantics defines the evaluation function by means of a generalized fuzzy inclusion measure, and the second one as a generalized similarity measure. These functions are parameterized so that their modification is simply achieved by tuning the functions' parameters. © 2007 Wiley Periodicals, Inc. Int J Int Syst 22: 665–689, 2007.     

Single-trial estimation of multichannel evoked-potential measurements

A method for single-trial estimation of multichannel evoked potentials is presented. The proposed method is based on the regularized least squares scheme. The spatial correlation between the channels is used as additional information in the estimation procedure. Amplitude estimates obtained with the proposed method is compared with the estimates calculated without using the spatial information. The performance of the method is evaluated using simulated and real data of P300 responses measured using auditory stimuli. The multichannel approach is shown to give realistic and comparable information about the amplitude differences of the P300 peak between different channels.     

Single-trial dynamical estimation of event-related potentials: a Kalman filter-based approach

A method for single-trial dynamical estimation of event-related potentials (ERPs) is presented. The method is based on recursive Bayesian mean square estimation and the estimators are obtained with a Kalman filtering procedure. We especially focus on the case that previous trials contain prior information of relevance to the trial being analyzed. The potentials are estimated sequentially using the previous estimates as prior information. The performance of the method is evaluated with simulations and with real P300 responses measured using auditory stimuli. Our approach is shown to have excellent capability of estimating dynamic changes form stimulus to stimulus present in the parameters of the ERPs, even in poor signal-to-noise ratio (SNR) conditions.     

Exact self-imaging of transversely periodic fields

Conditions for exactly self-imaging nonparaxial fields that are periodic also in the transverse direction are introduced. The theory is first derived by assuming full coherence and then extended into the domain of partial coherence. Different types of solutions are discussed, and some illustrations of the existence of solutions and intensity distributions of the fields are presented.     

Estimation of nonstationary EEG with Kalman smoother approach: an application to event-related synchronization (ERS)

An adaptive spectrum estimation method for nonstationary electroencephalogram by means of time-varying autoregressive moving average modeling is presented. The time-varying parameter estimation problem is solved by Kalman filtering along with a fixed-interval smoothing procedure. Kalman filter is an optimal filter in the mean square sense and it is a generalization of other adaptive filters such as recursive least squares or least mean square. Furthermore, by using the smoother the unavoidable tracking lag of adaptive filters can be avoided. Due to the properties of Kalman filter and benefits of the smoothing the time-frequency resolution of the presented Kalman smoother spectra is extremely high. The presented approach is applied to estimation of event-related synchronization/desynchronization (ERS/ERD) dynamics of occipital alpha rhythm measured from three healthy subjects. With the Kalman smoother approach detailed spectral information can be extracted from single ERS/ERD samples.     

A Schema for Flexile Equipment Control in Manufacturing Systems

In this work a methodology is proposed for increasing the flexibility of the control software of Flexible Manufacturing Systems (FMSs). This greater flexibility is required due to factors such as uncertain product demand, uneven distribution of shop load, and machine or cutting tool unavailability. In the proposed framework the following modules were developed: (a) an automated process planning module which generates non-linear process plans for a given part, considering the shop floor resource availability; the non-linear plans include both material handling and material processing information; (b) a planning module that linearises the process plan aiming at minimising the total manufacturing time of the parts; (c) a NC program generation module, which generates the NC program for the chosen CNC machine(s). In order to increase the flexibility of the control software even more, a resource model was devised and implemented, which provides the necessary resource information for the above modules. Each of these modules is described within this paper, and details about the part and process plan representation necessary for this implementation are also given. A case study is presented in order to show the capability of the methodology.     

Design and validation of an air-liquid interface (ALI) exposure device based on thermophoresis

In vitro, direct aerosol nanoparticle exposure of cells cultured at the air-liquid interface (ALI) has shown great potential over the conventional submerged cell exposure methods due to exposure relevancy and more accurate dose determination. Here, we present a design of an ALI cell exposure device, the thermocollector, which applies thermophoresis to deposit aerosol particles onto the cells. Computational numerical simulations were used to estimate the deposition flux and how it depended on particle properties. The deposition flux was approximately 250 particles/m²s for particles smaller than 100?nm, corresponding to an aerosol concentration of 1 #/cm³. This was also confirmed with experimental studies. For larger particles, the deposition rate depended more on particle properties; however, for fractal combustion derived soot particles, the deposition rate is practically size independent at the size range studied here. Finally, epithelial cells were exposed with wood combustion aerosol, and the toxicologic responses were investigated. The cell viability decrease and DNA damage were detected after the exposure. These effects were not detected in cells after the exposure to clean air in this cell exposure system.

Copyright © 2019 American Association for Aerosol Research     

Fabrication and characterization of vacuum deposited fluorescein thin films

Simple vacuum evaporation technique for deposition of dyes on various solid surfaces has been developed. The method is compatible with conventional solvent-free nanofabrication processing enabling fabrication of nanoscale optoelectronic devices. Thin films of fluorescein were deposited on glass, fluorine-tin-oxide (FTO) coated glass with and without atomically layer deposited (ALD) nanocrystalline 20 nm thick anatase TiO₂ coating. Surface topology, absorption and emission spectra of the films depend on their thickness and the material of supporting substrate. On a smooth glass surface the dye initially forms islands before merging into a uniform layer after 5 to 10 monolayers. On FTO covered glass the absorption spectra are similar to fluorescein solution in ethanol. Absorption spectra on ALD-TiO₂ is red shifted compared to the film deposited on bare FTO. The corresponding emission spectra at λ = 458 nm excitation show various thickness and substrate dependent features, while the emission of films deposited on TiO₂ is quenched due to the effective electron transfer to the semiconductor conduction band.