Document-Based databases: estudo exploratório no âmbito das Bases de Dados NoSQL

Com este artigo pretende-se dar um contributo para a clarificação de uma nova área da tecnologia de bases de dados que emergiu, recentemente, como resposta às dificuldades apresentadas pelo tradicional modelo relacional, no que diz respeito ao suporte do chamado Big Data – as bases de dados NoSQL. Em particular, pretende-se abordar uma das quatro classes de bases de dados em que o mundo NoSQL se divide – as Document-Based databases, de que produtos como o MongoDB e o CouchDB são alguns dos principais representantes. Como propósito do trabalho em que este artigo se enquadra, pretende-se perceber quais as diferenças, a nível de desempenho, entre soluções suportadas por estes dois produtos, quando utilizados no suporte de bases de dados de dimensão crescente, procurando evidenciar também as diferenças entre estas e soluções construídas recorrendo à bem conhecida tecnologia relacional.info:eu-repo/semantics/publishedVersio

Flexão composta : análise comparativa REBAP vs. EC2

No contexto actual nacional, o dimensionamento de estruturas de betão armado tem sido maioritariamente efectuado em conformidade com a norma nacional, o Regulamento de Estruturas de Betão Armado e Pré Esforçado (REBAP). Com a aprovação, no passado recente, do Eurocódigo 2 (EC2) a nível europeu, antevê-se que em breve lhe seja atribuído o estatuto de norma nacional, através da publicação de um texto idêntico. Em termos gerais o EC2, quando comparado com o REBAP, apresenta diferenças consideráveis na forma e no conteúdo que se repercutem no dimensionamento das estruturas de betão armado. Perante este cenário torna se imperioso efectuar estudos comparativos entre as duas normas aos mais diferentes níveis. O caso particular do dimensionamento à flexão ao nível da secção transversal em elementos estruturais lineares, que tem por base a hipótese de Navier Bernoulli (secções planas antes e após a deformação), recorre a leis tensões extensões de cálculo dos materiais intervenientes: o betão e o aço. As propostas do REBAP e do EC2 para definir estas leis são ligeiramente diferentes. Em trabalhos anteriores demonstrou se que as diferenças obtidas no dimensionamento de secções rectangulares à flexão simples adoptando as duas regulamentações (REBAP e EC2) são marginais. No presente trabalho pretende se avaliar a mesma diferença, mas desta feita para o caso em que o elemento estrutural se encontra sujeito a flexão composta. Deste modo, o objectivo é o de analisar a influência das diferenças que existem entre o REBAP e o EC2 ao nível dos diagramas tensões extensões de cálculo para os materiais betão e aço, no dimensionamento de secções rectangulares à flexão composta. No presente trabalho descreve se o estudo comparativo efectuado, assim como as principais conclusões obtidas

Process-based information systems development: taking advantage of a component-based infrastructure

Background: Owing to the highly competitive business environment in which contemporary organizations have to operate, a quick and effective way of developing and maintaining information systems is of utmost importance to their success. Obviously, the computerized information systems that support the everyday operations and management of organizations play a critical role in their competitiveness. For that reason, nowadays, more than ever, information systems have to be quickly developed, rapidly reconfigured, and easily maintained. Objectives: We aim to define a technological infrastructure, accompanied by a set of methodological development requirements, which might help to fulfil those needs. Methods/Approach: In this work, we followed a Design Science Research (DSR) approach. Results: We propose a specific IT infrastructure, inspired by the concept of a business process and using the functionalities provided by collaborative and workflow technologies, which allows the development of distributed IT solutions, Process-Based Information Systems (PBIS), in a component-based fashion. In the context of PBIS, we also propose a set of development requirements. Conclusions: We claim that Process-Based Information Systems allow organizations to evolve quickly and smoothly in face of changing business requirements, facilitating the integration of existing and future IT artefacts, while simplifying the overall development and maintenance effort of information systems.info:eu-repo/semantics/publishedVersio

The development of process-based information systems: methodological requirements

At the present time several issues are dramatically challenging the way we build and maintain information systems. On the one hand, owing to the extremely competitive conditions and dynamics of the business environment, it is vital for organisations to be able to develop and modify their information systems as quickly as possible, in order to succeed or even to keep in business. On the other hand, new technological developments have recently brought to the information systems infrastructure a set of new technologies with enormous potential to improve the way information systems support organisations. Collaborative technologies and, in particular, workflow, are notorious examples. In this paper, we propose a new information systems framework (Process-based Information Systems), which is able to provide organisations with the means to respond timely and adequately to the opportunities and threats of the business environment. Regarding this framework we try to identify the limitations of conventional Information Systems Development methodologies and, therefore, propose a set of new methodological requirements.COMPETE: POCI-01-0145-FEDER-007043 and FCT - Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2013info:eu-repo/semantics/publishedVersio

Introdução à propriedade intelectual, direito autoral, direito de software e direito da personalidade

Contém texto de apoio à unidade 1 do Cursos de Direitos Autorais. As atividades da Unidade 1 são: Atividade 1 - Apresentação de conceitos básicos Atividade 2 - Limites do direito autoral e de software Atividade 3 - Obras protegidas e obras não protegidas pelo direito autoral Atividade 4 - Criador e titular dos direitos patrimoniais de uma obra Atividade 5 - Obras audiovisuais e colaborativas Atividade 6 - Obra sob encomenda, sua cessão ou licença de direito Atividade 7 - Obra anônima, pseudônima, póstuma e obras colocadas em logradouro público

Correlation amplitude and entanglement entropy in random spin chains

Using strong-disorder renormalization group, numerical exact diagonalization, and quantum Monte Carlo methods, we revisit the random antiferromagnetic XXZ spin-1/2 chain focusing on the long-length and ground-state behavior of the average time-independent spin-spin correlation function C(l)=\upsilon l^{-\eta}. In addition to the well-known universal (disorder-independent) power-law exponent \eta=2, we find interesting universal features displayed by the prefactor \upsilon=\upsilon_o/3, if l is odd, and \upsilon=\upsilon_e/3, otherwise. Although \upsilon_o and \upsilon_e are nonuniversal (disorder dependent) and distinct in magnitude, the combination \upsilon_o + \upsilon_e = -1/4 is universal if C is computed along the symmetric (longitudinal) axis. The origin of the nonuniversalities of the prefactors is discussed in the renormalization-group framework where a solvable toy model is considered. Moreover, we relate the average correlation function with the average entanglement entropy, whose amplitude has been recently shown to be universal. The nonuniversalities of the prefactors are shown to contribute only to surface terms of the entropy. Finally, we discuss the experimental relevance of our results by computing the structure factor whose scaling properties, interestingly, depend on the correlation prefactors.Comment: v1: 16 pages, 15 figures; v2: 17 pages, improved discussions and statistics, references added, published versio

Exploring data analytics of data variety

The Internet allows organizations managers access to large amounts of data, and this data are presented in different formats, i.e., data variety, namely structured, semi-structured and unstructured. Based on the Internet, this data variety is partly derived from social networks, but not only, machines are also capable of sharing information among themselves, or even machines with people. The objective of this paper is to understand how to retrieve information from data analysis with data variety. An experiment was carried out, based on a dataset with two distinct data types, images and comments on cars. Techniques of data analysis were used, namely Natural Language Processing to identify patterns, and Sentimental and Emotional Analysis. The image recognition technique was used to associate a car model with a category. Next, OLAP cubes and their visualization through dashboards were created. This paper concludes that it is possible to extract a set of relevant information, namely identifying which cars people like more/less, among other information.COMPETE: POCI-01-0145-FEDER-007043 and FCT - Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/201

Influence of adhesive stiffness on the post-cracking behaviour of CFRP-reinforced structural glass beams

Reinforcement strategies have been developed to prevent catastrophic failures of glass structures after cracking. In this context, the composite action between glass and reinforcement plays a crucial role in the post-cracking performance of glass composite systems. Hence, this paper presents an experimental and numerical investigation on glass-CFRP composite beams manufactured using three different adhesives, with high, intermediate and low stiffness. The experimental programme comprised (i) mechanical characterization tests, (ii) tensile tests on double-lap joints and (iii) flexural tests on composite beams. Moreover, numerical simulations were carried out aiming at providing reliable numerical tools for the design of glass structural elements. Bending tests have shown that it is possible to obtain ductile failure modes in glass elements reinforced with CFRP laminates, sometimes attaining or surpassing the cracking load during the post-cracking phase, depending on the type of adhesive. On the other hand, glass-CFRP composite beams manufactured with stiff, moderate and flexible adhesives were well simulated (i) neglecting the physical existence of the adhesive layer, (ii) assuming the linear elastic behaviour of the adhesive, and (iii) modelling the bond behaviour of the adhesive joint, respectively.This work is financed by the national funds through Fundação para a Ciência e a Tecnologia, IP (FCT), under the grant agreement [SFRH/BD/122428/2016] attributed to the 1st author. This work was partly financed by FCT/MCTES through national funds (PIDDAC) under the R&D Unit Institute for Sustainability and Innovation in Structural Engineering (ISISE), under reference UIDB/04029/2020

Feasibility of mechanical post-tensioning of annealed glass beams by activating externally bonded Fe-SMA reinforcement

The structural concept of post-tensioned glass systems has been investigated to minimize the unpredictable response of structural glass in tension. The Fe-SMAs have been successfully explored for strengthening existing structures due to their advantages in comparison with the conventional reinforcement materials. In particular, the recently developed Fe-17Mn-5Si-10Cr-4Ni-1VC (mass-%) alloy seems sustainable and shows promising properties for the construction industry. This study investigates the feasibility of post-tensioning glass beams by activating externally bonded Fe-SMA strips. The investigation is mainly focussed on (i) the activation process of Fe-SMA strips, with temperatures ranging between 120 °C and 160 °C, and (ii) the advantages of this reinforcement for post-tensioning of glass structural elements, in terms of applicability and structural response. Flexural tests show that it is possible to obtain ductile failure modes when glass beams are reinforced with passive or activated Fe-SMA strips. Activation of Fe-SMA strips resulted in an increase of up to 30 % of the cracking load.The first author wishes to acknowledge the grant SFRH/BD/122428/2016 provided by Fundação para a Ciência e a Tecnologia, IP (FCT), financed by European Social Fund and by national funds through the FCT/MCTES. This work was partly financed by FCT / MCTES through national funds (PIDDAC) under the R&D Unit Institute for Sustainability and Innovation in Structural Engineering (ISISE), under reference UIDB/04029/2020