Face Recognition using Probabilistic Neural Networks

In this paper we address the problem of face detection and recognition of grey scale frontal view images. We propose a face recognition system based on probabilistic neural networks (PNN) architecture. The system is implemented using voronoi/ delaunay tessellations and template matching. Images are segmented successfully into homogeneous regions by virtue of voronoi diagram properties. Face verification is achieved using matching scores computed by correlating edge gradients of reference images. The advantage of classification using PNN models is its short training time. The correlation based template matching guarantees good classification results

Face Recognition using Probabilistic Neural Networks

n this paper we address the problem of face detection and recognition of grey scale frontal view images. We propose a face recognition system based on probabilistic neural networks (PNN) architecture. The system is implemented using voronoi/ delaunay tessellations and template matching. Images are segmented successfully into homogeneous regions by virtue of voronoi diagram properties. Face verification is achieved using matching scores computed by correlating edge gradients of reference images. The advantage of classification using PNN models is its short training time. The correlation based template matching guarantees good classification results.

Comparison of Computer-Based and Optical Face Recognition Paradigms

The main objectives of this thesis are to validate an improved principal components analysis (IPCA) algorithm on images; designing and simulating a digital model for image compression, face recognition and image detection by using a principal components analysis (PCA) algorithm and the IPCA algorithm; designing and simulating an optical model for face recognition and object detection by using the joint transform correlator (JTC); establishing detection and recognition thresholds for each model; comparing between the performance of the PCA algorithm and the performance of the IPCA algorithm in compression, recognition and, detection; and comparing between the performance of the digital model and the performance of the optical model in recognition and detection. The MATLAB © software was used for simulating the models. PCA is a technique used for identifying patterns in data and representing the data in order to highlight any similarities or differences. The identification of patterns in data of high dimensions (more than three dimensions) is too difficult because the graphical representation of data is impossible. Therefore, PCA is a powerful method for analyzing data. IPCA is another statistical tool for identifying patterns in data. It uses information theory for improving PCA. The joint transform correlator (JTC) is an optical correlator used for synthesizing a frequency plane filter for coherent optical systems. The IPCA algorithm, in general, behaves better than the PCA algorithm in the most of the applications. It is better than the PCA algorithm in image compression because it obtains higher compression, more accurate reconstruction, and faster processing speed with acceptable errors; in addition, it is better than the PCA algorithm in real-time image detection due to the fact that it achieves the smallest error rate as well as remarkable speed. On the other hand, the PCA algorithm performs better than the IPCA algorithm in face recognition because it offers an acceptable error rate, easy calculation, and a reasonable speed. Finally, in detection and recognition, the performance of the digital model is better than the performance of the optical model.

A video-based biometric authentication for e-learning web applications

In the last years there was an exponential growth in the offering of Web-enabled distance courses and in the number of enrolments in corporate and higher education using this modality. However, the lack of efficient mechanisms that assures user authentication in this sort of environment, in the system login as well as throughout his session, has been pointed out as a serious deficiency. Some studies have been led about possible biometric applications for web authentication. However, password based authentication still prevails. With the popularization of biometric enabled devices and resultant fall of prices for the collection of biometric traits, biometrics is reconsidered as a secure remote authentication form for web applications. In this work, the face recognition accuracy, captured on-line by a webcam in Internet environment, is investigated, simulating the natural interaction of a person in the context of a distance course environment. Partial results show that this technique can be successfully applied to confirm the presence of users throughout the course attendance in an educational distance course. An efficient client/server architecture is also proposed. © 2009 Springer Berlin Heidelberg.

Análise de técnicas de reconhecimento de padrões para a identificação biométrica de usuários em aplicações WEB Utilizando faces a partir de vídeos

Pós-graduação em Ciência da Computação - IBILCE

Sviluppo di un'applicazione bioinformatica per la gestione dei dati di antibiotico sensibilità di isolati clinici

Il problema dell'antibiotico-resistenza è un problema di sanità pubblica per affrontare il quale è necessario un sistema di sorveglianza basato sulla raccolta e l'analisi dei dati epidemiologici di laboratorio. Il progetto di dottorato è consistito nello sviluppo di una applicazione web per la gestione di tali dati di antibiotico sensibilità di isolati clinici utilizzabile a livello di ospedale. Si è creata una piattaforma web associata a un database relazionale per avere un’applicazione dinamica che potesse essere aggiornata facilmente inserendo nuovi dati senza dover manualmente modificare le pagine HTML che compongono l’applicazione stessa. E’ stato utilizzato il database open-source MySQL in quanto presenta numerosi vantaggi: estremamente stabile, elevate prestazioni, supportato da una grande comunità online ed inoltre gratuito. Il contenuto dinamico dell’applicazione web deve essere generato da un linguaggio di programmazione tipo “scripting” che automatizzi operazioni di inserimento, modifica, cancellazione, visualizzazione di larghe quantità di dati. E’ stato scelto il PHP, linguaggio open-source sviluppato appositamente per la realizzazione di pagine web dinamiche, perfettamente utilizzabile con il database MySQL. E’ stata definita l’architettura del database creando le tabelle contenenti i dati e le relazioni tra di esse: le anagrafiche, i dati relativi ai campioni, microrganismi isolati e agli antibiogrammi con le categorie interpretative relative al dato antibiotico. Definite tabelle e relazioni del database è stato scritto il codice associato alle funzioni principali: inserimento manuale di antibiogrammi, importazione di antibiogrammi multipli provenienti da file esportati da strumenti automatizzati, modifica/eliminazione degli antibiogrammi precedenti inseriti nel sistema, analisi dei dati presenti nel database con tendenze e andamenti relativi alla prevalenza di specie microbiche e alla chemioresistenza degli stessi, corredate da grafici. Lo sviluppo ha incluso continui test delle funzioni via via implementate usando reali dati clinici e sono stati introdotti appositi controlli e l’introduzione di una semplice e pulita veste grafica.

Ranking web services using centralities and social indicators

Nowadays, developers of web application mashups face a sheer overwhelming variety and pluralism of web services. Therefore, choosing appropriate web services to achieve specific goals requires a certain amount of knowledge as well as expertise. In order to support users in choosing appropriate web services it is not only important to match their search criteria to a dataset of possible choices but also to rank the results according to their relevance, thus minimizing the time it takes for taking such a choice. Therefore, we investigated six ranking approaches in an empirical manner and compared them to each other. Moreover, we have had a look on how one can combine those ranking algorithms linearly in order to maximize the quality of their outputs.

The heteromeric 5-HT3A/B receptor:the effect of 5-HT3B subunits on receptor structure and ligand recognition

The 5-HT3 receptors are members of the cys-loop family of ligand-gated ion channels. Two functional subtypes are known, the homomeric 5HT3A and the heteromeric 5HT3A/B receptors, which exhibit distinct biophysical characteristics but are difficult to differentiate pharmacologically. Atomic force microscopy has been used to determine the stoichiometry and architecture of the heteromeric 5HT3A/B receptor. Each subunit was engineered to express a unique C-terminal epitope tag, together with six sequential histidine residues to facilitate nickel affinity purification. The 5-HT3 receptors, ectopically expressed in HEK293 cells, were solubilised, purified and decorated with antibodies to the subunit specific epitope tags. Imaging of individual receptors by atomic force microscopy revealed a pentameric arrangement of subunits in the order BBABA, reading anti-clockwise when viewed from the extracellular face. Homology models for the heteromeric receptor were then constructed using both the electron microscopic structure of the nicotinic acetylcholine receptor, from Torpedo marmorata, and the X-ray crystallographic structure of the soluble acetylcholine binding protein, from Lymnaea stagnalis, as templates. These homology models were used, together with equivalent models constructed for the homomeric receptor, to interpret mutagenesis experiments designed to explore the minimal recognition differences of both the natural agonist, 5-HT, and the competitive antagonist, granisetron, for the two human receptor subtypes. The results of this work revealed that the 5-HT3B subunit residues within the ligand binding site, for both the agonist and antagonist, are accommodating to conservative mutations. They are consistent with the view that the 5-HT3A subunit provides the principal and the 5-HT38 subunit the complementary recognition interactions at the binding interface.

Before characterizing faces

[EN]This paper describes the approach for face detection and selection of frontal views, for further processing. This approach based on color detection and symmetry operator application, is integrated in an Active Vision System o ering promising results just making use of some opportunistic skills.

Plataforma de gestão de incidentes

Mestrado em Engenharia Electrotécnica e de Computadores. Área de Especialização de Telecomunicações.

Sistemas de prevenção de cuidados de saúde

A tomada de decisão na saúde pode-se tornar um processo complexo e moroso. A complexidade associada ao processo de decisão na saúde advém da diversidade de opções clinicamente razoáveis, ou seja, nenhuma opção se sobrepõem _a outra, visto que cada uma possui os seus riscos e benefícios, que são normalmente interpretados de modo diferente entre os indivíduos. Desta forma, cabe ao paciente e _a sua equipa médica optarem pela opção que melhor se enquadra na situação clínica do paciente Para tornar este processo menos complexo, cada vez mais se utiliza as chamadas "ferramentas de decisão", que se caraterizam por fornecer informação sobre as diferentes opções clínicas, traduzindo-se numa diminuição da dificuldade da tomada de decisão. De uma forma geral, as ferramentas de decisão são desenvolvidas com o intuito de facilitar a tomada de decisão, através do aumento do conhecimento científico sobre um determinado problema (tomada de decisão informada) e uma mudança de atitude do paciente face aos seus cuidados de saúde. Na realização da presente dissertação foi desenvolvido um sistema de informação na web, que engloba informação relativa ao rastreio do cancro da próstata. Este sistema também surge acoplado a um conjunto de componentes de decisão, que têm como objetivo auxiliar os indivíduos no processo de decisão para a realização do rastreio do cancro da próstata, assim como a prevenção de doenças relacionadas com a próstata. A implementação desta aplicação web teve como base as necessidades do indivíduo, ou seja informações clínicas sobre possíveis riscos e benefícios associados ao rastreio, assim como fornecer uma maior interatividade com o utilizador. A primeira versão da aplicação já foi testada e avaliada através da participação de um conjunto de indivíduos que compõem o público-alvo para este tipo de aplicações. Os resultados obtidos permitiram concluir que os requisitos definidos para esta aplicação, permitem o aumento do conhecimento do indivíduo e o auxílio na tomada de decisão para a realização do rastreio do cancro da próstata.

Classificação e agregação automática de notícias desportivas

Mestrado em Engenharia Informática - Área de Especialização em Arquiteturas, Sistemas e Redes

Emotions in a Web-based Learning Environment

The aim of this thesis was to examine emotions in a web-based learning environment (WBLE). Theoretically, the thesis was grounded on the dimensional model of emotions. Four empirical studies were conducted. Study I focused on students’ anxiety and their self-efficacy in computer-using situations. Studies II and III examined the influence of experienced emotions on students’ collaborative visible and non-collaborative invisible activities and lurking in a WBLE. Study II also focused on the antecedents of the emotions students experience in a web-based learning environment. Study IV concentrated on clarifying the differences between emotions experienced in face-to-face and web-based collaborative learning. The results of these studies are reported in four original research articles published in scientific journals. The present studies demonstrate that emotions are important determinants of student behaviour in a web-based learning, and justify the conclusion that interactions on the web can and do have an emotional content. Based on the results of these empirical studies, it can be concluded that the emotions students experience during the web-based learning result mostly from the social interactions rather than from the technological context. The studies indicate that the technology itself is not the only antecedent of students’ emotional reactions in the collaborative web-based learning situations. However, the technology itself also exerted an influence on students’ behaviour. It was found that students’ computer anxiety was associated with their negative expectations of the consequences of using technology-based learning environments in their studies. Moreover, the results also indicated that student behaviours in a WBLE can be divided into three partially overlapping classes: i) collaborative visible ii) non-collaborative invisible activities, and iii) lurking. What is more, students’ emotions experienced during the web-based learning affected how actively they participated in such activities in the environment. Especially lurkers, i.e. students who seldom participated in discussions but frequently visited the online environment, experienced more negatively valenced emotions during the courses than did the other students. This result indicates that such negatively toned emotional experiences can make the lurking individuals less eager to participate in other WBLE courses in the future. Therefore, future research should also focus more precisely on the reasons that cause individuals to lurk in online learning groups, and the development of learning tasks that do not encourage or permit lurking or inactivity. Finally, the results from the study comparing emotional reactions in web-based and face-to-face collaborative learning indicated that the learning by means of web-based communication resulted in more affective reactivity when compared to learning in a face-to-face situation. The results imply that the students in the web-based learning group experienced more intense emotions than the students in the face-to-face learning group.The interpretations of this result are that the lack of means for expressing emotional reactions and perceiving others’ emotions increased the affectivity in the web-based learning groups. Such increased affective reactivity could, for example, debilitate individual’s learning performance, especially in complex learning tasks. Therefore, it is recommended that in the future more studies should be focused on the possibilities to express emotions in a text-based web environment to ensure better means for communicating emotions, and subsequently, possibly decrease the high level of affectivity. However, we do not yet know whether the use of means for communicating emotional expressions via the web (for example, “smileys” or “emoticons”) would be beneficial or disadvantageous in formal learning situations. Therefore, future studies should also focus on assessing how the use of such symbols as a means for expressing emotions in a text-based web environment would affect students’ and teachers’ behaviour and emotional state in web-based learning environments.

Monitorización de la integración de sistemas intensivos software

El software se ha convertido en el eje central del mundo actual, una compleja creación humana que influye en la vida, negocios y comunicación de todas las personas pertenecientes a la Sociedad de la Información. El rápido crecimiento experimentado en el ámbito del desarrollo software ha permitido la creación de avanzadas estructuras tecnológicas, denominadas “Sistemas Intensivos Software”, capaces de comunicarse con otros sistemas, dispositivos, sensores y personas. A lo largo de los próximos años los sistemas se enfrentarán a una mayor complejidad, surgida de la necesidad de operar en entornos de grandes dimensiones y de comportamientos no deterministas. Los métodos y herramientas actuales no son lo suficientemente potentes para diseñar, construir,implementar y mantener sistemas intensivos software con estas características, y detener la construcción de sistemas intensivos software o construir sistemas poco flexibles o fiables no es una alternativa real. En el desarrollo de “Sistemas Intensivos Software” pueden llegar a intervenir distintas entidades o compañías software que suelen estar en ubicaciones geográficas distintas y constituidas por grandes equipos de desarrollo, multidisciplinares e incluso multilingües. Debido a la criticidad del resultado de las actividades realizadas de forma independiente en el sistema resultante, éstas se han de controlar y monitorizar para asegurar la correcta integración de todos los elementos del sistema completo. El objetivo de este proyecto es la creación de una herramienta software para dar soporte a la gestión y monitorización de la construcción e integración de sistemas intensivos software, siendo extensible también a proyectos de otra índole. La herramienta resultante se denomina Positioning System, una aplicación web del tipo SPA (Single Page Application) creada con tecnología de última generación como el framework JavaScript AngularJS y tecnología de back-end como SlimPHP. Positioning System provee la funcionalidad necesaria para la creación de proyectos, familias y subfamilias de productos que constituyen los productos software de los proyectos creados, así como la gestión de socios comerciales y gestión de contactos de dichos proyectos. Todas estas funcionalidades son fácilmente monitorizadas y controladas por gráficos estadísticos generados para cada proyecto. ABSTRACT Software has become the backbone of today’s world, a complex human creation that has an important impact in the life, business and communication of all people involved with the Information Society. The quick growth that software development has undergone for last years has enabled the creation of advanced technological structures called “Software Intensive Systems”. They are able to communicate with other systems, devices, sensors and people. Next years, systems will face more complexity. It arises from the need of operating systems of large dimensions with non-deterministic behaviors. Current methods and tools are not powerful enough to design, build, implement and maintain software intensive systems; however stopping the development or developing unreliable and non-flexible systems is not a real alternative. Software Intensive Systems” development may involve different entities or software companies which may be in different geographical locations and may be constituted by large, multidisciplinary and even multilingual development teams. Due to the criticality of the result of each conducted activity, independently in the resulting system, these activities must be controlled and monitored to ensure the proper integration of all the elements within the complete system. The goal of this project is the creation of a software tool to support the management and monitoring of the construction and integration of software intensive systems, being possible to be extended to other kind of projects. The resultant tool is called Positioning System, a web application that follows the SPA (Single Page Application) style. It was created with the latest technologies, such as, the AngularJS framework and SlimPHP. The Positioning System provides the necessary features for the creation of projects, families and subfamilies of products that constitute the software products of the created projects, as well as the management of business partners and contacts of these projects. All these features are easily monitored and controlled by statistical graphs generated for each project.

Off-line signature verification and forgery detection system based on fuzzy modeling

This paper presents an innovative approach for signature verification and forgery detection based on fuzzy modeling. The signature image is binarized and resized to a fixed size window and is then thinned. The thinned image is then partitioned into a fixed number of eight sub-images called boxes. This partition is done using the horizontal density approximation approach. Each sub-image is then further resized and again partitioned into twelve further sub-images using the uniform partitioning approach. The features of consideration are normalized vector angle (α) from each box. Each feature extracted from sample signatures gives rise to a fuzzy set. Since the choice of a proper fuzzification function is crucial for verification, we have devised a new fuzzification function with structural parameters, which is able to adapt to the variations in fuzzy sets. This function is employed to develop a complete forgery detection and verification system.