Among the various frameworks in which electroencephalographic (EEG) signal synchronization has been traditionally formulated, the most widely studied and used is the coherence that is entirely based on frequency analysis. However, at present time it is possible to capture information about the temporal profile of coherence, which is particularly helpful in studying non-stationary time-varying brain dynamics, like the wavelet coherence (WC). In this paper we propose a new approach of studying brain synchronization dynamics by extending the use of WC to include certain statistically significant (in terms of signal coherence) time segments, to study and characterize any disturbances present in the functional connectivity network of schizophrenia patients. Graph theoretical measures and visualization provide the tools to study the "disconnection syndrome" as proposed for schizophrenia. Specifically, we analyzed multichannel EEG data from twenty stabilized patients with schizophrenia and controls in an experiment of working memory (WM) using the gamma band (i.e., the EEG frequency of ca. 40 Hz), which is activated during the connecting activity (i.e., the "binding" of the neurons). The results are in accordance with the disturbance of connections between the neurons giving additional information related to the localization of most prominent disconnection.

Electroencephalographic signal synchronization studies have been a topic of increasing interest lately, using both linear and nonlinear formulations. In this direction a graph-theoretic approach devised to study and stress the coupling dynamics of task-performing dynamical networks is proposed in this communication. Graph theoretical measures and visualization provide the tools to visualize and characterize the topology of a brain network as in an alcoholism paradigm during mental rehearsal of pictures, which is known to reflect synchronization impairment. More specifically, in this chapter the synchronization between all pairs of channels is calculated using (a) the magnitude squared coherence, (b) an estimation of phase synchronization, and (c) a robust nonlinear state-space generalized synchronization assessment method. Synchronization matrices define graphs whose topological structure and properties are characterized using measures for graphs and weighted networks. The results are in accordance with previous psychophysiology studies suggesting that an alcoholic subject has impaired synchronization of brain activity and loss of lateralization during the rehearsal process, most prominently in alpha (8-12 Hz) band, as compared to a control subject. Lower beta (13-30 Hz) synchronization was also evident in an alcoholic subject.

A lot of tools have been created lately in order to simulate how a vision impaired or color-blind person would perceive web rich-client applications and content. In this work we propose a simulation tool for non-web Java TM Swing applications. The aim is to assist the developers in preventing accessibility barriers and improving the overall quality throughout the design and implementation phases of the whole development process.

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