A type system for access control in an object-oriented language

Trabalho apresentado no âmbito do Mestrado em Engenharia Informática, como requisito parcial para obtenção do grau de Mestre em Engenharia Informática

The electric vehicles as a mean to reduce Co2 emissions and energy costs in isolated regions: the São Miguel (Azores) case study

Most of small islands around the world today, are dependent on imported fossil fuels for the majority of their energy needs especially for transport activities and electricity production. The use of locally renewable energy resources and the implementation of energy efficiency measures could make a significant contribution to their economic development by reducing fossil fuel imports. An electrification of vehicles has been suggested as a way to both reduce pollutant emissions and increase security of supply of the transportation sector by reducing the dependence on oil products imports and facilitate the accommodation of renewable electricity generation, such as wind and, in the case of volcanic islands like Sao Miguel (Azores) of the geothermal energy whose penetration has been limited by the valley electricity consumption level. In this research, three scenarios of EV penetration were studied and it was verified that, for a 15% LD fleet replacement by EVs with 90% of all energy needs occurring during the night, the accommodation of 10 MW of new geothermal capacity becomes viable. Under this scenario, reductions of 8% in electricity costs, 14% in energy, 23% in fossil fuels use and CO2 emissions for the transportation and electricity production sectors could be expected.

The effects of parental sensitivity and involvement in caregiving on mother–infant and father–infant attachment in a portuguese sample

In the present longitudinal study, we investigated attachment quality in Portuguese mother–infant and in father–infant dyads, and evaluated whether attachment quality was related to parental sensitivity during parent–infant social interaction or to the amount of time each parent spent with the infant during play and in routine caregiving activities (e.g., feeding, bathing, play). The sample consisted of 82 healthy full-term infants (30 girls, 53 boys, 48 first born), and their mothers and fathers from mostly middle-class households. To assess parental sensitivity, mothers and fathers were independently observed during free play interactions with their infants when infants were 9 and 15 months old. The videotaped interactions were scored by masked coders using the Crittenden’s CARE-Index. When infants were 12 and 18 months old, mother–infant and father–infant dyads were videotaped during an adaptation of Ainsworth’s Strange Situation. Parents also described their level of involvement in infant caregiving activities using a Portuguese version of the McBride and Mills Parent Responsibility Scale. Mothers were rated as being more sensitive than fathers during parent–infant free play at both 9 and 15 months. There also was a higher prevalence of secure attachment in mother–infant versus father–infant dyads at both 12 and 18 months. Attachment security was predicted by the amount of time mothers and fathers were involved in caregiving and play with the infant, and with parents’ behavior during parent–infant free play.

Integration of e-portfolios in learning management systems

The LMS plays a decisive role in most eLearning environments. Although they integrate many useful tools for managing eLearning activities, they must also be effectively integrated with other specialized systems typically found in an educational environment such as Repositories of Learning Objects or ePortfolio Systems. Both types of systems evolved separately but in recent years the trend is to combine them, allowing the LMS to benefit from using the ePortfolio assessment features. This paper details the most common strategies for integrating an ePortfolio system into an LMS: the data, the API and the tool integration strategies. It presents a comparative study of strategies based on the technical skills, degree of coupling, security features, batch integration, development effort, status and standardization. This study is validated through the integration of two of the most representative systems on each category - respectively Mahara and Moodle.

Portuguese strategy for occupational safety and health 2008-2012 for public administration : priorites for action, progress in the implementation of the proposed measures and their impact on occupational safety outcomes

Apresentação realizada no OH&S Forum 2011 - International Forum on Occupational Health and Safety: Policies, profiles and services, na Finlândia de, 20 a 22 Junho de 2011.

Service-oriented mobility of java code in web services-based architectures

Dissertação apresentada na Faculdade de Ciências e Tecnologias da Universidade Nova de Lisboa para a obtenção do Grau de Mestre em Engenharia Informática

A new model for EEZ surveillance and management in Portugal

Management Information Systems 2000, p. 103-111

Integration in MASCEM of the Joint Dispatch of Energy and Reserves Provided by Generation and Demand Resources

The provision of reserves in power systems is of great importance in what concerns keeping an adequate and acceptable level of security and reliability. This need for reserves and the way they are defined and dispatched gain increasing importance in the present and future context of smart grids and electricity markets due to their inherent competitive environment. This paper concerns a methodology proposed by the authors, which aims to jointly and optimally dispatch both generation and demand response resources to provide the amounts of reserve required for the system operation. Virtual Power Players are especially important for the aggregation of small size demand response and generation resources. The proposed methodology has been implemented in MASCEM, a multi agent system also developed at the authors’ research center for the simulation of electricity markets.

Crescer em família: A permanência no acolhimento familiar

O acolhimento familiar oferece um contexto de vida à criança retirada da sua família biológica, por um período de tempo indeterminado que se pode prolongar, no limite, até à maioridade ou independência. Um contexto familiar estável permite desenvolver sentimentos de segurança e de permanência associados à possibilidade de manutenção dos contactos com a sua família biológica. A criança pode e deve, em muitas circunstâncias, permanecer com os seus acolhedores e o reconhecimento deste papel parental é um passo que pode contribuir para afastar ambiguidades e indefinições que são prejudiciais para o sistema e para as práticas que ele vai configurando. Em Portugal, todavia, o acolhimento familiar é umamedida de carácter temporário, cuja aplicação depende da previsibilidade do retorno da criança ou do jovem à família de origem. O objetivo deste artigo é, após uma breve caracterização do sistema de proteção de crianças e jovens português, analisar a permanência no acolhimento familiar de 2006 a 2011, a partir dos relatórios de caracterização das crianças e jovens emsituação de acolhimento. De seguida procedemos à apresentação e discussão de dados recolhidos num estudo desenvolvido no distrito do Porto, englobando as 289 crianças que se encontravamacolhidas emmaio de 2011, e que representavam52%das colocações familiares de crianças em Portugal.Os resultados foram apurados com a aplicação de um formulário de recolha de dados preenchido a partir dos registos oficiais de cada criança acolhida e através da realização de 52 entrevistas a acolhedores. Entre os resultados principais destacam-se os longos períodos de estadia, a permanência da criança na família acolhedora inicial e a avaliação global positiva dos resultados obtidos, o que nos permite identificar um conjunto de desafios que se colocam no futuro imediato ao acolhimento familiar português.

An intelligent clustering scheme for distributed intrusion detection in vehicular cloud computing

In recent years, vehicular cloud computing (VCC) has emerged as a new technology which is being used in wide range of applications in the area of multimedia-based healthcare applications. In VCC, vehicles act as the intelligent machines which can be used to collect and transfer the healthcare data to the local, or global sites for storage, and computation purposes, as vehicles are having comparatively limited storage and computation power for handling the multimedia files. However, due to the dynamic changes in topology, and lack of centralized monitoring points, this information can be altered, or misused. These security breaches can result in disastrous consequences such as-loss of life or financial frauds. Therefore, to address these issues, a learning automata-assisted distributive intrusion detection system is designed based on clustering. Although there exist a number of applications where the proposed scheme can be applied but, we have taken multimedia-based healthcare application for illustration of the proposed scheme. In the proposed scheme, learning automata (LA) are assumed to be stationed on the vehicles which take clustering decisions intelligently and select one of the members of the group as a cluster-head. The cluster-heads then assist in efficient storage and dissemination of information through a cloud-based infrastructure. To secure the proposed scheme from malicious activities, standard cryptographic technique is used in which the auotmaton learns from the environment and takes adaptive decisions for identification of any malicious activity in the network. A reward and penalty is given by the stochastic environment where an automaton performs its actions so that it updates its action probability vector after getting the reinforcement signal from the environment. The proposed scheme was evaluated using extensive simulations on ns-2 with SUMO. The results obtained indicate that the proposed scheme yields an improvement of 10 % in detection rate of malicious nodes when compared with the existing schemes.

An Enhanced WLAN Security System With FPGA Implementation for Multimedia Applications

Maintaining a high level of data security with a low impact on system performance is more challenging in wireless multimedia applications. Protocols that are used for wireless local area network (WLAN) security are known to significantly degrade performance. In this paper, we propose an enhanced security system for a WLAN. Our new design aims to decrease the processing delay and increase both the speed and throughput of the system, thereby making it more efficient for multimedia applications. Our design is based on the idea of offloading computationally intensive encryption and authentication services to the end systems’ CPUs. The security operations are performed by the hosts’ central processor (which is usually a powerful processor) before delivering the data to a wireless card (which usually has a low-performance processor). By adopting this design, we show that both the delay and the jitter are significantly reduced. At the access point, we improve the performance of network processing hardware for real-time cryptographic processing by using a specialized processor implemented with field-programmable gate array technology. Furthermore, we use enhanced techniques to implement the Counter (CTR) Mode with Cipher Block Chaining Message Authentication Code Protocol (CCMP) and the CTR protocol. Our experiments show that it requires timing in the range of 20–40 μs to perform data encryption and authentication on different end-host CPUs (e.g., Intel Core i5, i7, and AMD 6-Core) as compared with 10–50 ms when performed using the wireless card. Furthermore, when compared with the standard WiFi protected access II (WPA2), results show that our proposed security system improved the speed to up to 3.7 times.

A Green Approach for Selfish Misbehavior Detection in 802.11-Based Wireless Networks

IEEE 802.11 is one of the most well-established and widely used standard for wireless LAN. Its Medium Access control (MAC) layer assumes that the devices adhere to the standard’s rules and timers to assure fair access and sharing of the medium. However, wireless cards driver flexibility and configurability make it possible for selfish misbehaving nodes to take advantages over the other well-behaving nodes. The existence of selfish nodes degrades the QoS for the other devices in the network and may increase their energy consumption. In this paper we propose a green solution for selfish misbehavior detection in IEEE 802.11-based wireless networks. The proposed scheme works in two phases: Global phase which detects whether the network contains selfish nodes or not, and Local phase which identifies which node or nodes within the network are selfish. Usually, the network must be frequently examined for selfish nodes during its operation since any node may act selfishly. Our solution is green in the sense that it saves the network resources as it avoids wasting the nodes energy by examining all the individual nodes of being selfish when it is not necessary. The proposed detection algorithm is evaluated using extensive OPNET simulations. The results show that the Global network metric clearly indicates the existence of a selfish node while the Local nodes metric successfully identified the selfish node(s). We also provide mathematical analysis for the selfish misbehaving and derived formulas for the successful channel access probability.

Supporting NAT traversal and secure communications in a protocol implementation framework

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do Grau de Mestre em Engenharia Electrotécnica e de Computadores

Students’ reading behavior: digital vs. print preferences in portuguese context

The aim of this paper is to present the main Portuguese results from a multi-national study on reading format preferences and behaviors from undergraduate students from Polytechnic Institute of Porto (Portugal). For this purpose we apply an adaptation of the Academic Reading Questionnaire previously created by Mizrachi (2014). This survey instrument has 14 Likert-style statements regarding the format influence in the students reading behavior, including aspects such as ability to remember, feelings about access convenience, active engagement with the text by highlighting and annotating, and ability to review and concentrate on the text. The importance of the language and dimension of the text to determine the preference format is also inquired. Students are also asked about the electronic device they use to read digital documents. Finally, some demographic and academic data were gathered. The analysis of the results will be contextualized on a review of the literature concerning youngsters reading format preferences. The format (digital or print) in which a text is displayed and read can impact comprehension, which is an important information literacy skill. This is a quite relevant issue for class readings in academic context because it impacts learning. On the other hand, students preferences on reading formats will influence the use of library services. However, literature is not unanimous on this subject. Woody, Daniel and Baker (2010) concluded that the experience of reading is not the same in electronic or print context and that students prefer print books than e-books. This thesis is reinforced by Ji, Michaels and Waterman (2014) which report that among 101 undergraduates the large majority self-reported to read and learn more when they use printed format despite the fact that they prefer electronically supplied readings instead of those supplied in printed form. On the other side, Rockinson-Szapkiw, et al (2013) conducted a study were they demonstrate that e-textbook is as effective for learning as the traditional textbook and that students who choose e-textbook had significantly higher perceived learning than students who chose to use print textbooks.

A Brother or a Sister With CP. How Much it Makes a Difference in Childhood and Adulthood?

Every month we see to be published dozens of scientific papers about etiology and physiopathology of CP, imaging, treatment, survival, quality of life of patients and of mothers (just a few) and so on. Papers dealing with the feelings and the problems of siblings of children and adults with CP in the most important scientific journals are extremely rare. However in internet we can find the sites of the most important Cerebral Palsy Societies, like the British, the Australian and the American ones already devoting a special attention to the issue of siblings; we also can see several interesting blogs of parents sharing their experiences not only with the handicapped child but also with the siblings, even counseling some books written for children giving practical advices how to deal and live with a handicapped sibling. What was a surprise to me were the several sites of adults having a disabled sibling, frequently with CP, in a new situation: without parents to care them.