Adaptive Sparse Detector for Suppressing Powerline Component in EEG Measurements

Powerline interference (PLI) is a major source of interference in the acquisition of electroencephalogram (EEG) signal. Digital notch filters (DNFs) have been widely used to remove the PLI such that actual features, which are weak in energy and strongly connected to brain states, can be extracted explicitly. However, DNFs are mathematically implemented via discrete Fourier analysis, the problem of overlapping between spectral counterparts of PLI and those of EEG features is inevitable. In spite of their effectiveness, DNFs usually cause distortions on the extracted EEG features, which may lead to incorrect diagnostic results. To address this problem, we investigate an adaptive sparse detector for reducing PLI. This novel approach is proposed based on sparse representation inspired by self-adaptive machine learning. In the coding phase, an overcomplete dictionary, which consists of redundant harmonic waves with equally spaced frequencies, is employed to represent the corrupted EEG signal. A strategy based on the split augmented Lagrangian shrinkage algorithm is employed to optimize the associated representation coefficients. It is verified that spectral components related to PLI are compressed into a narrow area in the frequency domain, thus reducing overlapping with features of interest. In the decoding phase, eliminating of coefficients within the narrow band area can remove the PLI from the reconstructed signal. The sparsity of the signal in the dictionary domain is determined by the redundancy factor. A selection criteria of the redundancy factor is suggested via numerical simulations. Experiments have shown the proposed approach can ensure less distortions on actual EEG features.

Presence and image of Mexico in Moroccan newspaper Al-Ittihad Al-Ichtiraki

This research claims to reveal the image of Mexico in the Moroccan press, specifically in the newspaper Al Ittihad Al Ichtraki. The main purpose of this research is to investigate the associated representation of Mexico of this press by using different methods such as qualitative, thematic, and stylistic. The main objective can be defined as to explain motivations that make the press to lead that representation. The second objective of this study, related to the first, is to study the position of this information. Therefore, during this research analyzing methodology has been used to qualitificate, measure and accomplish by conclusions.

Tracking crystallophore nucleating properties: setting-up a database for statistical analysis

ABSTRACTIn this article, the principle of a database aimed at facilitating the understanding of the unique protein nucleating properties of the Crystallophore is presented. A first analysis allows us to compare the efficiency of Tb-Xo4 with the new Lu-Xo4 variant, featuring improved phasing properties. Then, the concept of subset-of-interest is introduced to reveal potential antagonistic/synergistic effects between Tb-Xo4 and physico-chemical parameters of the crystallisation kits such as pH. The overall approach may be of interest for any studies working on solutions dedicated to improve the nucleating step in protein crystallization.TOC GraphicSynopsisA database and associated representation tools are highlighted to understand nucleating properties of the crystallophore.

An Associated Representation Method for Defining Agricultural Cases in a Case-Based Reasoning System for Fast Case Retrieval

As an artificial intelligence technique, case-based reasoning has considerable potential to build intelligent systems for smart agriculture, providing farmers with advice about farming operation management. A proper case representation method plays a crucial role in case-based reasoning systems. Some methods like textual, attribute-value pair, and ontological representations have been well explored by researchers. However, these methods may lead to inefficient case retrieval when a large volume of data is stored in the case base. Thus, an associated representation method is proposed in this paper for fast case retrieval. Each case is interconnected with several similar and dissimilar ones. Once a new case is reported, its features are compared with historical data by similarity measurements for identifying a relative similar past case. The similarity of associated cases is measured preferentially, instead of comparing all the cases in the case base. Experiments on case retrieval were performed between the associated case representation and traditional methods, following two criteria: the number of visited cases and retrieval accuracy. The result demonstrates that our proposal enables fast case retrieval with promising accuracy by visiting fewer past cases. In conclusion, the associated case representation method outperforms traditional methods in the aspect of retrieval efficiency.

Uniformization of p-adic curves via Higgs–de Rham flows

Let k be an algebraic closure of a finite field of odd characteristic. We prove that for any rank two graded Higgs bundle with maximal Higgs field over a generic hyperbolic curve {X_{1}} defined over k, there exists a lifting X of the curve to the ring {W(k)} of Witt vectors as well as a lifting of the Higgs bundle to a periodic Higgs bundle over {X/W(k)} . These liftings give rise to a two-dimensional absolutely irreducible representation of the arithmetic fundamental group {\pi_{1}(X_{K})} of the generic fiber of X. This curve X and its associated representation is in close relation to the canonical curve and its associated canonical crystalline representation in the p-adic Teichmüller theory for curves due to S. Mochizuki. Our result may be viewed as an analogue of the Hitchin–Simpson’s uniformization theory of hyperbolic Riemann surfaces via Higgs bundles.

The Role of Location-Context Binding in Nonspatial Visual Working Memory

Successful retrieval of an item from visual working memory (VWM) often requires an associated representation of the trial-unique context in which that item was presented. We dissociated the effects on fMRI signal of memory load versus context binding by comparing nonspatial VWM for one oriented bar vs. three bars individuated by their location on the screen vs. three items drawn from different categories (orientation, color, and luminance), for which location context was superfluous. Delay-period fMRI signal in frontal and parietal cortex was sensitive to stimulus homogeneity rather than to memory load per se. Behavioral performance revealed a broad range in swap errors, an index of the efficacy of context binding, and subjects were classified as high swap error or low swap error. During the delay period, the strength of the representation of stimulus location in parietal cortex predicted individual differences in swap errors. During recall, activity in occipital cortex revealed two dissociable neural correlates of context binding: high swap-error subjects allocated less spatial attention to the location of the probed item and more spatial attention the location of non-probed items; high swap-error subjects also represented the orientation of the probed item more weakly and the orientation of nonprobed items more strongly. Our results suggest context binding is a computation that influences all stages of VWM processing.Significance StatementAlthough we often think of the contents of visual working memory (VWM) as representations of the items that need to be remembered, each item’s trial-unique context is also critical for successful performance. For example, if one observes a red, then a black, then a blue car passing through an intersection, vivid memory for the colors, alone, wouldn’t allow one to execute the instruction “Follow the first of the three cars that just drove by.” Although manipulating load is commonly assumed to isolate storage functions, requiring memory for multiple items drawn from the same category also increases demands on the context binding needed to individuate these items. This experiment tracked the influence of context binding on VWM stimulus processing.

Generalised Cogrowth series, random walks, and the group determinant

We associate to a groupGa series that generalises the cogrowth series ofGand is related to a random walk onG. We show that the series is rational if and only ifGis finite, generalizing a result of Kouksov [Kou]. We show that whenGis finite, the series determinesG. There are naturally occurring ideals and varieties that are acted on by Aut(G). We study these and generalize this to the context ofS-rings over finite groups. There is an associated representation of Aut(G) and we characterize when this is irreducible.

Multi-Tier Tensile Strain Models for Strain-Based Design: Part 1 — Fundamental Basis

This is the first paper in a three-paper series on the tensile strain design of pipelines. The formulation of the multi-tier models [1] and evaluation of the models against experiment data [2] are presented in two companion papers. This paper starts with an introduction of general concept of strain-based design. The central part of the paper is then devoted to the tensile strain capacity, including (1) physical process of tensile strain failure, (2) limit states of tensile strain failure and associated toughness representation, and (3) fundamental basis of tensile strain models. The most significant part of the fundamental basis, the limit state of tensile failure and associated representation of the material’s toughness, is given the greatest amount of attention.