844 resultados para bag-of-features


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We propose a study of the mathematical properties of voice as an audio signal -- This work includes signals in which the channel conditions are not ideal for emotion recognition -- Multiresolution analysis- discrete wavelet transform – was performed through the use of Daubechies Wavelet Family (Db1-Haar, Db6, Db8, Db10) allowing the decomposition of the initial audio signal into sets of coefficients on which a set of features was extracted and analyzed statistically in order to differentiate emotional states -- ANNs proved to be a system that allows an appropriate classification of such states -- This study shows that the extracted features using wavelet decomposition are enough to analyze and extract emotional content in audio signals presenting a high accuracy rate in classification of emotional states without the need to use other kinds of classical frequency-time features -- Accordingly, this paper seeks to characterize mathematically the six basic emotions in humans: boredom, disgust, happiness, anxiety, anger and sadness, also included the neutrality, for a total of seven states to identify

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While humans can easily segregate and track a speaker's voice in a loud noisy environment, most modern speech recognition systems still perform poorly in loud background noise. The computational principles behind auditory source segregation in humans is not yet fully understood. In this dissertation, we develop a computational model for source segregation inspired by auditory processing in the brain. To support the key principles behind the computational model, we conduct a series of electro-encephalography experiments using both simple tone-based stimuli and more natural speech stimulus. Most source segregation algorithms utilize some form of prior information about the target speaker or use more than one simultaneous recording of the noisy speech mixtures. Other methods develop models on the noise characteristics. Source segregation of simultaneous speech mixtures with a single microphone recording and no knowledge of the target speaker is still a challenge. Using the principle of temporal coherence, we develop a novel computational model that exploits the difference in the temporal evolution of features that belong to different sources to perform unsupervised monaural source segregation. While using no prior information about the target speaker, this method can gracefully incorporate knowledge about the target speaker to further enhance the segregation.Through a series of EEG experiments we collect neurological evidence to support the principle behind the model. Aside from its unusual structure and computational innovations, the proposed model provides testable hypotheses of the physiological mechanisms of the remarkable perceptual ability of humans to segregate acoustic sources, and of its psychophysical manifestations in navigating complex sensory environments. Results from EEG experiments provide further insights into the assumptions behind the model and provide motivation for future single unit studies that can provide more direct evidence for the principle of temporal coherence.

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The Open Journal project has completed its three year period of funding by the UK Electronic Libraries (eLib) programme (Rusbridge 1998). During that time, the number of journals that are available electronically leapt from a few tens to a few thousand. Some of these journals are now developing the sort of features the project has been advocating, in particular the use of links within journals, between different primary journals, with secondary journals data, and to non-journal sources. Assessing the achievements of the project and considering some of the difficulties it faced, we report on the different approaches to linking that the project developed, and summarise the important user responses that indicate what works and what does not. Looking ahead, there are signs of change, not just to simple linking within journals but to schemes in which links are the basis of "distributed" journals, where information may be shared and documents built from different sources. The significance has yet to be appreciated, but this would be a major change from printed journals. If projects such as this and others have provided the initial impetus, the motivation for distributed journals comes, perhaps surprisingly, from within certain parts of the industry, as the paper shows.

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The large number of opinions generated by online users made the former “word of mouth” find its way to virtual world. In addition to be numerous, many of the useful reviews are mixed with a large number of fraudulent, incomplete or duplicate reviews. However, how to find the features that influence on the number of votes received by an opinion and find useful reviews? The literature on opinion mining has several studies and techniques that are able to analyze of properties found in the text of reviews. This paper presents the application of a methodology for evaluation of usefulness of opinions with the aim of identifying which characteristics have more influence on the amount of votes: basic utility (e.g. ratings about the product and/or service, date of publication), textual (e.g.size of words, paragraphs) and semantics (e.g., the meaning of the words of the text). The evaluation was performed in a database extracted from TripAdvisor with opinionsabout hotels written in Portuguese. Results show that users give more attention to recent opinions with higher scores for value and location of the hotel and with lowest scores for sleep quality and service and cleanliness. Texts with positive opinions, small words, few adjectives and adverbs increase the chances of receiving more votes.

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The research that led to this dissertation adopted a set of scenic/ideological aspects inherent to the productions of the Culture Industry as its object of research. The intellectual output of Theodor W. Adorno and Max Horkheimer underscored the approaches on this subject, since it provides the same set of scenic/ideological features to be explored because, according to the authors, scenes produced by the culture industry are linked to the dominant ideology, since they act in favor of maintaining the status quo. The first objective was the definition this set of features inherent to the scene produced by the culture industry, through the exploration of literature produced by Adorno and Horkheimer, so it was possible to define a set composed of nine elements: Construction of characters as characteristic types; Stereotypes; Naturalization of Stereotyped language; Simplistic playwriting; Reuse dramatic formula; Love and sexuality as themes of plots; Utilization of tragic element; Objetive representation; Approximation of fiction and reality. The second goal was the analysis of scene produced by the culture industry nowadays, so that it was possible to verify if any scenic/ideological aspects indicated by Adorno and Horkheimer in the mid-twentieth century were present among the productions from this beginning of the twenty-first century. Through the analysis of three soap operas produced in Brazil in 2012, it was found that the nine scenic/ideological aspects as indicated by Adorno and Horkheimer appeared in the observed productions. Additionally, a new scenic/ideological feature, not indicated by Adorno and Horkheimer is present: the merchandising

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As introduced by Bentley et al. (2005), artificial immune systems (AIS) are lacking tissue, which is present in one form or another in all living multi-cellular organisms. Some have argued that this concept in the context of AIS brings little novelty to the already saturated field of the immune inspired computational research. This article aims to show that such a component of an AIS has the potential to bring an advantage to a data processing algorithm in terms of data pre-processing, clustering and extraction of features desired by the immune inspired system. The proposed tissue algorithm is based on self-organizing networks, such as self-organizing maps (SOM) developed by Kohonen (1996) and an analogy of the so called Toll-Like Receptors (TLR) affecting the activation function of the clusters developed by the SOM.

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Recent years have seen an astronomical rise in SQL Injection Attacks (SQLIAs) used to compromise the confidentiality, authentication and integrity of organisations’ databases. Intruders becoming smarter in obfuscating web requests to evade detection combined with increasing volumes of web traffic from the Internet of Things (IoT), cloud-hosted and on-premise business applications have made it evident that the existing approaches of mostly static signature lack the ability to cope with novel signatures. A SQLIA detection and prevention solution can be achieved through exploring an alternative bio-inspired supervised learning approach that uses input of labelled dataset of numerical attributes in classifying true positives and negatives. We present in this paper a Numerical Encoding to Tame SQLIA (NETSQLIA) that implements a proof of concept for scalable numerical encoding of features to a dataset attributes with labelled class obtained from deep web traffic analysis. In the numerical attributes encoding: the model leverages proxy in the interception and decryption of web traffic. The intercepted web requests are then assembled for front-end SQL parsing and pattern matching by applying traditional Non-Deterministic Finite Automaton (NFA). This paper is intended for a technique of numerical attributes extraction of any size primed as an input dataset to an Artificial Neural Network (ANN) and statistical Machine Learning (ML) algorithms implemented using Two-Class Averaged Perceptron (TCAP) and Two-Class Logistic Regression (TCLR) respectively. This methodology then forms the subject of the empirical evaluation of the suitability of this model in the accurate classification of both legitimate web requests and SQLIA payloads.

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This case study presents the general profile of the successful EFL online apprentice in the Colombian public vocational institution, SENA. This profile is described in terms of demographic, academic and cognitive aspects. The demographic profile is composed of features like sex, age, marital status and present job; the academic profile comprises information related to study habits, reasons to study English online, previous English learning experiences and type of ICT tools at home; and the cognitive profile refers to learning styles and EFL learning strategies. Four online surveys addressed to 33 successful online apprentices provide the data, which are also analyzed by means of a basic statistical description supported by Excel. The findings allow the author to conclude that the successful EFL online apprentice in SENA is basically a single person who is unemployed but has access to ICT tools to move forward in his learning process. Additionally, this apprentice has a divergent learning style who prefers the metacognitive, social and memory learning strategies for the EFL online process.

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Dissertação apresentada ao Instituto Politécnico de Castelo Branco para cumprimento dos requisitos necessários à obtenção do grau de Mestre em Desenvolvimento de Software e Sistemas Interativos, realizada sob a orientação científica do Doutor Fernando Reinaldo Silva Garcia Ribeiro e do Doutor José Carlos Meireles Monteiro Metrôlho, Professores Adjuntos da Unidade Técnico-Científica de Informática da Escola Superior de Tecnologia do Instituto Politécnico de Castelo Branco.

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As introduced by Bentley et al. (2005), artificial immune systems (AIS) are lacking tissue, which is present in one form or another in all living multi-cellular organisms. Some have argued that this concept in the context of AIS brings little novelty to the already saturated field of the immune inspired computational research. This article aims to show that such a component of an AIS has the potential to bring an advantage to a data processing algorithm in terms of data pre-processing, clustering and extraction of features desired by the immune inspired system. The proposed tissue algorithm is based on self-organizing networks, such as self-organizing maps (SOM) developed by Kohonen (1996) and an analogy of the so called Toll-Like Receptors (TLR) affecting the activation function of the clusters developed by the SOM.

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Entrepreneurs are individuals who can transform economic and social realities by promoting development, so it became important tools in generating externalities in regions where they operate. In Brazil, 59.9% of new ventures do not reach the fourth year of life, the mortality rate of new ventures is high. The causes of mortality are numerous, and within the behavioral aspects, one is the locus of control. This study determines the degree of association between internal locus of control and achieving business success of entrepreneurs in Rio Grande do Norte who participated in the workshop EMPRETEC. The approach that studies the behavior entrepreneurs agreed that there are psychological characteristics associated with a set of values, attitudes and needs that determine the behavior and induce the entrepreneur to achieve success. Among these features is the locus of control, a skill that individuals must identify in their actions, or lack of them, the causes of their successes and failures. The locus is external when the individual attributes to factors outside themselves as causes of their results, and is built in when you can identify the actions that led to success. We surveyed 223 entrepreneurs statewide who answered the questionnaire for assessing the scale of locus of control, selfassessment questionnaire of entrepreneurial characteristics of EMPRETEC and a questionnaire assessing the business success. 71.9% were identified as having success. Among the behavioral characteristics strongest in the group of entrepreneurs are setting goals and commitment. Was found for locus of control mean value of 7.35, confidence interval between 7.05 and 7.66. Showing that the locus of control group is predominantly internal. We also found a correlation between the locus and commitment, between setting goals and commitment; calculated risks and information search; search of information and commitment, and between commitment and independence and self confidence. Dependence was not identified among the set of features and business success, determining the absence of an ideal profile. However, logistic regression significant association was found indicating that the smaller the individual's locus of control increased the likelihood of it achieving business success

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On Rio Grande do Norte northern coast the process of sediment transport are intensely controlled by wind and sea (waves and currents) action, causing erosion and shoreline morphological instability. Due to the importance of such coastal zone it was realized the multi-spectral mapping and physical-chemical characterization of mudflats and mangroves aiming to support the mitigating actions related to the containment of the erosive process on the oil fields of Macau and Serra installed at the study area. The multi-spectral bands of 2000 and 2008 LANDSAT 5 TM images were submitted on the several digital processing steps and RGB color compositions integrating spectral bands and Principal Components. Such processing methodology was important to the mapping of different units on surface, together with field works. It was possible to make an analogy of the spectral characteristics of wetlands with vegetations areas (mangrove), showing the possibility to make a restoration of this area, contributing with the environmental monitoring of that ecosystem. The maps of several units were integrated in GIS environment at 1:60,000 scale, including the classification of features according to the presence or absence of vegetation cover. Thus, the strategy of methodology established that there are 10.13 km2 at least of sandy-muddy and of these approximately 0.89 km2 with the possibility to be used in a reforestation of typical flora of mangrove. The physical-chemical characterization showed areas with potential to introduce local species of mangrove and they had a pH above neutral with a mean of 8.4. The characteristic particle size is sand in the fine fractions, the high levels of carbonate, organic matter and major and trace element in general are concentrated where the sediment had the less particles size, showing the high correlation that those elements have with smaller particles of sediment. The application of that methodological strategy is relevant to the better understanding of features behavior and physical-chemical data of sediment samples collected on field allow the analysis of efficiency/capability of sandy-muddy to reforestation with local mangrove species for mitigation of the erosive action and coastal processes on the areas occupied by the oil industry

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The research that led to this dissertation adopted a set of scenic/ideological aspects inherent to the productions of the Culture Industry as its object of research. The intellectual output of Theodor W. Adorno and Max Horkheimer underscored the approaches on this subject, since it provides the same set of scenic/ideological features to be explored because, according to the authors, scenes produced by the culture industry are linked to the dominant ideology, since they act in favor of maintaining the status quo. The first objective was the definition this set of features inherent to the scene produced by the culture industry, through the exploration of literature produced by Adorno and Horkheimer, so it was possible to define a set composed of nine elements: Construction of characters as characteristic types; Stereotypes; Naturalization of Stereotyped language; Simplistic playwriting; Reuse dramatic formula; Love and sexuality as themes of plots; Utilization of tragic element; Objetive representation; Approximation of fiction and reality. The second goal was the analysis of scene produced by the culture industry nowadays, so that it was possible to verify if any scenic/ideological aspects indicated by Adorno and Horkheimer in the mid-twentieth century were present among the productions from this beginning of the twenty-first century. Through the analysis of three soap operas produced in Brazil in 2012, it was found that the nine scenic/ideological aspects as indicated by Adorno and Horkheimer appeared in the observed productions. Additionally, a new scenic/ideological feature, not indicated by Adorno and Horkheimer is present: the merchandising

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Personal electronic devices, such as cell phones and tablets, continue to decrease in size while the number of features and add-ons keep increasing. One particular feature of great interest is an integrated projector system. Laser pico-projectors have been considered, but the technology has not been developed enough to warrant integration. With new advancements in diode technology and MEMS devices, laser-based projection is currently being advanced for pico-projectors. A primary problem encountered when using a pico-projector is coherent interference known as speckle. Laser speckle can lead to eye irritation and headaches after prolonged viewing. Diffractive optical elements known as diffusers have been examined as a means to lower speckle contrast. Diffusers are often rotated to achieve temporal averaging of the spatial phase pattern provided by diffuser surface. While diffusers are unable to completely eliminate speckle, they can be utilized to decrease the resultant contrast to provide a more visually acceptable image. This dissertation measures the reduction in speckle contrast achievable through the use of diffractive diffusers. A theoretical Fourier optics model is used to provide the diffuser’s stationary and in-motion performance in terms of the resultant contrast level. Contrast measurements of two diffractive diffusers are calculated theoretically and compared with experimental results. In addition, a novel binary diffuser design based on Hadamard matrices will be presented. Using two static in-line Hadamard diffusers eliminates the need for rotation or vibration of the diffuser for temporal averaging. Two Hadamard diffusers were fabricated and contrast values were subsequently measured, showing good agreement with theory and simulated values. Monochromatic speckle contrast values of 0.40 were achieved using the Hadamard diffusers. Finally, color laser projection devices require the use of red, green, and blue laser sources; therefore, using a monochromatic diffractive diffuser may not optimal for color speckle contrast reduction. A simulation of the Hadamard diffusers is conducted to determine the optimum spacing between the two diffusers for polychromatic speckle reduction. Experimental measured results are presented using the optimal spacing of Hadamard diffusers for RGB color speckle reduction, showing 60% reduction in contrast.

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In clinical documents, medical terms are often expressed in multi-word phrases. Traditional topic modelling approaches relying on the “bag-of-words” assumption are not effective in extracting topic themes from clinical documents. This paper proposes to first extract medical phrases using an off-the-shelf tool for medical concept mention extraction, and then train a topic model which takes a hierarchy of Pitman-Yor processes as prior for modelling the generation of phrases of arbitrary length. Experimental results on patients’ discharge summaries show that the proposed approach outperforms the state-of-the-art topical phrase extraction model on both perplexity and topic coherence measure and finds more interpretable topics.