1,970 research outputs found

    Exploring the potential of 3D Zernike descriptors and SVM for protein\u2013protein interface prediction

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    Abstract Background The correct determination of protein–protein interaction interfaces is important for understanding disease mechanisms and for rational drug design. To date, several computational methods for the prediction of protein interfaces have been developed, but the interface prediction problem is still not fully understood. Experimental evidence suggests that the location of binding sites is imprinted in the protein structure, but there are major differences among the interfaces of the various protein types: the characterising properties can vary a lot depending on the interaction type and function. The selection of an optimal set of features characterising the protein interface and the development of an effective method to represent and capture the complex protein recognition patterns are of paramount importance for this task. Results In this work we investigate the potential of a novel local surface descriptor based on 3D Zernike moments for the interface prediction task. Descriptors invariant to roto-translations are extracted from circular patches of the protein surface enriched with physico-chemical properties from the HQI8 amino acid index set, and are used as samples for a binary classification problem. Support Vector Machines are used as a classifier to distinguish interface local surface patches from non-interface ones. The proposed method was validated on 16 classes of proteins extracted from the Protein–Protein Docking Benchmark 5.0 and compared to other state-of-the-art protein interface predictors (SPPIDER, PrISE and NPS-HomPPI). Conclusions The 3D Zernike descriptors are able to capture the similarity among patterns of physico-chemical and biochemical properties mapped on the protein surface arising from the various spatial arrangements of the underlying residues, and their usage can be easily extended to other sets of amino acid properties. The results suggest that the choice of a proper set of features characterising the protein interface is crucial for the interface prediction task, and that optimality strongly depends on the class of proteins whose interface we want to characterise. We postulate that different protein classes should be treated separately and that it is necessary to identify an optimal set of features for each protein class

    Design and implementation of a multi-modal biometric system for company access control

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    This paper is about the design, implementation, and deployment of a multi-modal biometric system to grant access to a company structure and to internal zones in the company itself. Face and iris have been chosen as biometric traits. Face is feasible for non-intrusive checking with a minimum cooperation from the subject, while iris supports very accurate recognition procedure at a higher grade of invasivity. The recognition of the face trait is based on the Local Binary Patterns histograms, and the Daughman\u2019s method is implemented for the analysis of the iris data. The recognition process may require either the acquisition of the user\u2019s face only or the serial acquisition of both the user\u2019s face and iris, depending on the confidence level of the decision with respect to the set of security levels and requirements, stated in a formal way in the Service Level Agreement at a negotiation phase. The quality of the decision depends on the setting of proper different thresholds in the decision modules for the two biometric traits. Any time the quality of the decision is not good enough, the system activates proper rules, which ask for new acquisitions (and decisions), possibly with different threshold values, resulting in a system not with a fixed and predefined behaviour, but one which complies with the actual acquisition context. Rules are formalized as deduction rules and grouped together to represent \u201cresponse behaviors\u201d according to the previous analysis. Therefore, there are different possible working flows, since the actual response of the recognition process depends on the output of the decision making modules that compose the system. Finally, the deployment phase is described, together with the results from the testing, based on the AT&T Face Database and the UBIRIS database

    Classificazione di campioni di vegetazione

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    Consumers’ Attitudes on Services of General Interest in the EU: Accessibility, Price and Quality 2000-2004

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    The research question addressed by this paper is a simple one: are European consumers happy with the services provided by the utilities after two decades of reforms? We focus on electricity, gas, water, telephone in the EU 15 Member States. The variables we analyse are consumers’ satisfaction with accessibility, price and quality, as reported in three waves of Eurobarometer survey, 2000-2002-2004, comprising around 47,000 observations. We use ordered logit models to analyze the impact of privatization and regulatory reforms, as represented by an OECD dataset, controlling for individual and country characteristics. Our results do not support a clear association between consumers’ satisfaction and a standard reform package of privatization, vertical disintegration, liberalization.Consumers’ Satisfaction, Gas, Electricity, Telephone, Water, Eurobarometer

    On the determination of certain basic types of supersonic flow fields

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    A discussion is given of the application of Fourier series techniques to the problems of linearized supersonic flow. The formulation presented is an extension of the doublet type of "fundamental solution" to higher order types of singularity. The equations developed have application to wing theory but are primarily of importance in wing-body interaction problems. A specific example of a wing-body interference problem is discussed in light of the presented methods

    On rotational conical flow

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    Some general properties of isoenergetic rotational conical fields are determined. For such fields, provided the physical parameters of the fluid flow are known on a conical reference surface, it being understood that they satisfy certain imposed conditions, it is shown how to construct the hodographs in the various meridional semiplanes, as the envelope of either the tangents to the hodographs or of the osculatory circles

    Electrical equipment for the experimental study of the dynamics of fluids

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    This report contains the description of electric anemometers and their application to the study of turbulent fluid flows, of electric tanks for the realization of the analogies between electrology and aerodynamics and their application to the study of varied technical problems, and lastly of the electric condenser type dynamometer and its application to the prediction of the aerodynamic forces on wing and airplane models in wind-tunnel tests and in controlled and spontaneous rotations

    National parks in Italy: Sustainable tourism marketing strategies

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    In Italy there are different forms of management for protected areas, depending on the type of area, e.g. national or regional parks, natural reserves and marine reserves. The management of national parks is the most consolidated. Every park is managed jointly by a president, a board of directors and a park community, which all together form a board representing every local authority in the area. National parks are under the direct jurisdiction of the Environment Ministry and they are dependent upon it financially. Often they are created in inland and poorly developed areas with problems of unemployment and depopulation. Currently, due to the shortage of funds, the managers of national parks are increasingly conscious of the role of parks in local development and of the need to find economic resources. Consequently, they are thinking of new marketing policies with a strategic approach to governance. Today, protected natural areas have become tourist destinations of increasing importance. They are not seen as places to be preserved intact and turned into museums, but rather as areas that need investment to favour the development of sustainable tourism. For this reason, the strategic aims of parks are increasingly focused on tourist marketing activities aimed at new tourist segments, often market niches, which should create extra wealth and employment whilst respecting the environment. Therefore, to become competitive in tourism, parks must carry out strategic marketing activities, identify the main target markets and create tourism products to be promoted. To achieve these aims... (see the PDF file).In Italy there are different forms of management for protected areas, depending on the type of area, e.g. national or regional parks, natural reserves and marine reserves. The management of national parks is the most consolidated. Every park is managed jointly by a president, a board of directors and a park community, which all together form a board representing every local authority in the area. National parks are under the direct jurisdiction of the Environment Ministry and they are dependent upon it financially. Often they are created in inland and poorly developed areas with problems of unemployment and depopulation. Currently, due to the shortage of funds, the managers of national parks are increasingly conscious of the role of parks in local development and of the need to find economic resources. Consequently, they are thinking of new marketing policies with a strategic approach to governance. Today, protected natural areas have become tourist destinations of increasing importance. They are not seen as places to be preserved intact and turned into museums, but rather as areas that need investment to favour the development of sustainable tourism. For this reason, the strategic aims of parks are increasingly focused on tourist marketing activities aimed at new tourist segments, often market niches, which should create extra wealth and employment whilst respecting the environment. Therefore, to become competitive in tourism, parks must carry out strategic marketing activities, identify the main target markets and create tourism products to be promoted. To achieve these aims... (see the PDF file)

    The Role of Mindfulness, Mind Wandering, Attentional Control, and Maladaptive Personality Traits in Problematic Gaming Behavior

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    Objectives Problematic gaming has become a phenomenon of growing clinical relevance due to its negative impact on life and mental health outcomes. Much research has been carried out on its complex aetiology, and some studies have suggested that dispositional mindfulness, mind wandering, attentional control, and maladaptive personality traits may play some role, but they have never been included in the same prediction model. This study used Gaussian graphical models and Bayesian networks to investigate the pattern of association of these constructs and of background and gaming-related variables with problematic gaming in a sample of adult gamers. Method Participants (n=506) were administered an online survey comprising a questionnaire on background and gaming-related variables and the Gaming Disorder Test, the Five Facet Mindfulness Questionnaire-15, the Mind WanderingSpontaneous and Deliberate scales, the Attention Control-Distraction and Shifting scales, and the Personality Inventory for DSM-5-Brief Form. Results Gaussian graphical models showed that problematic gaming was directly associated with Acting with Awareness, Disinhibition, Psychoticism, playing more than 30 hr a week, ability level, and playing strategy games. Bayesian networks indicated that the occurrence of high levels of problematic gaming directly depended on the presence of low scores on Acting with Awareness. Conclusions The results suggest that one key feature of problematic gamers can be a high level of spontaneous thinking, either in the form of mind wandering or in the lack of Acting with Awareness, while maladaptive personality traits and attentional control seem to play a less central role
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