Internet Protocol (IP) design and implementation for efficient mobility to devices in wireless networks

The purpose of this thesis was to develop an efficient routing protocol which would provide mobility support to the mobile devices roaming within a network. The routing protocol need to be compatible with the existing internet architecture. The routing protocol proposed here is based on the Mobile IP routing protocol and could solve some of the problems existing in current Mobile IP implementation e.g. ingress filtering problem. By implementing an efficient timeout mechanism and introducing Paging mechanism to the wireless network, the protocol minimizes the number of control messages sent over the network. The implementation of the system is primarily done on three components: 1) Mobile devices that need to gain access to the network, 2) Router which would be providing roaming support to the mobile devices and 3) Database server providing basic authentication services on the system. As a result, an efficient IP routing protocol is developed which would provide seamless mobility to the mobile devices on the network.

Circular migration and the Internet: The role of social networks in the sociocultural context of Mexican residents in Barcelona

This work focuses on the study of the circular migration between America and Europe, particularly in the discussion about knowledge transfer and the way that social networks reconfigure the form of information distribution among people, that due to labor and academic issues have left their own country. The main purpose of this work is to study the impact of social media use in migration flows between Mexico and Spain, more specifically the use by Mexican migrants who have moved for  multiple years principally for educational purposes and then have returned to their respective locations in Mexico seeking to integrate themselves into the labor market. Our data collection concentrated exclusively on a group created on Facebook by Mexicans who mostly reside in Barcelona, Spain or wish to travel to the city for economic, educational or tourist reasons.  The results of this research show that while social networks are spaces for exchange and integration, there is a clear tendency by this group to "narrow lines" and to look back to their homeland, slowing the process of opening socially in their new context.

Dynamical models for computer viruses propagation

Nowadays, digital computer systems and networks are the main engineering tools, being used in planning, design, operation, and control of all sizes of building, transportation, machinery, business, and life maintaining devices. Consequently, computer viruses became one of the most important sources of uncertainty, contributing to decrease the reliability of vital activities. A lot of antivirus programs have been developed, but they are limited to detecting and removing infections, based on previous knowledge of the virus code. In spite of having good adaptation capability, these programs work just as vaccines against diseases and are not able to prevent new infections based on the network state. Here, a trial on modeling computer viruses propagation dynamics relates it to other notable events occurring in the network permitting to establish preventive policies in the network management. Data from three different viruses are collected in the Internet and two different identification techniques, autoregressive and Fourier analyses, are applied showing that it is possible to forecast the dynamics of a new virus propagation by using the data collected from other viruses that formerly infected the network. Copyright (c) 2008 J. R. C. Piqueira and F. B. Cesar. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

A Taxonomy for Locality Algorithms on Peer-to-Peer Networks

The continuous growth of peer-to-peer networks has made them responsible for a considerable portion of the current Internet traffic. For this reason, improvements in P2P network resources usage are of central importance. One effective approach for addressing this issue is the deployment of locality algorithms, which allow the system to optimize the peers` selection policy for different network situations and, thus, maximize performance. To date, several locality algorithms have been proposed for use in P2P networks. However, they usually adopt heterogeneous criteria for measuring the proximity between peers, which hinders a coherent comparison between the different solutions. In this paper, we develop a thoroughly review of popular locality algorithms, based on three main characteristics: the adopted network architecture, distance metric, and resulting peer selection algorithm. As result of this study, we propose a novel and generic taxonomy for locality algorithms in peer-to-peer networks, aiming to enable a better and more coherent evaluation of any individual locality algorithm.

Interactive health communication in preventive medicine - Internet-based strategies in teaching and research

Interactive health communication using Internet technologies is expanding the range and flexibility of intervention and teaching options available in preventive medicine and the health sciences. Advantages of interactive health communication include the enhanced convenience, novelty, and appeal of computer-mediated communication; its flexibility and interactivity; and automated processing. We outline some of these fundamental aspects of computer-mediated communication as it applies to preventive medicine. Further, a number of key pathways of information technology evolution are creating new opportunities for the delivery of professional education in preventive medicine and other health domains, as well as for delivering automated, self-instructional health behavior-change programs through the Internet. We briefly describe several of these key evolutionary pathways, We describe some examples from work we have done in Australia. These demonstrate how we have creatively responded to the challenges of these new information environments, and how they may be pursued in the education of preventive medicine and other health care practitioners and in the development and delivery of health behavior change programs through the Internet. Innovative and thoughtful applications of this new technology can increase the consistency, reliability, and quality of information delivered.

Albert-László Barabási, Linked – The New Science of Networks, Perseus, Cambridge, 2002. Duncan J. Watts, Six Degrees – The Science of a Connected Age, William Heinemann, Londres, 2003.

Com a criação da teoria das redes, assistiu-se nos últimos anos a uma revolução científica de carácter interdisciplinar Não é uma teoria inteiramente nova, tendo sido precedida pela criação por P. Erdvos, nos anos sessenta, da teoria dos grafos aleatórios. Esta última é uma teoria puramente matemática, donde termos escrito “grafo” em lugar de “rede”. Apenas recentemente podemos falar de uma efectiva teoria das redes reais, e isso devido ao abandono de algumas das ideias essenciais avançadas por Erdvos, em especial a ideia de partir de um conjunto previamente dado de nós, os quais de seguida vão sendo conectados aleatoriamente com probabilidade p. Este quadro geral começou a ser modificado pelo chamado modelo dos “mundo-pequenos” proposto em 1998 por Duncan Watts e Steve Strogatz, modificação que se tornou ainda mais radical quando, em 1999, Albert Barabási e colaboradores propuseram um modelo no qual os nós vão progressivamente nascendo e conectados por uma função de preferência: um nó conecta-se em proporção às ligações que os outros nós já possuem, pelo que quantas mais ligações um nó possui maior a probabilidade de receber ulteriores ligações.

Supporting internet protocols in master-slave fieldbus networks

In this paper we describe how to integrate Internet Protocols (IP) into a typical hierarchical master-slave fieldbus network, supporting a logical ring token passing mechanism between master stations. The integration of the TCP/IP protocols in the fieldbus protocol rises a number of issues that must be addressed properly. In this paper we particularly address the issues related to the conveyance of IP fragments in fieldbus frames (fragmentation/de-fragmentation) and on how to support the symmetry inherent to the TCP/IP protocols in fieldbus slaves, which lack communication initiative.

Supporting real-time distributed computer-controlled systems with multi-hop P-NET networks

Fieldbus communication networks aim to interconnect sensors, actuators and controllers within process control applications. Therefore, they constitute the foundation upon which real-time distributed computer-controlled systems can be implemented. P-NET is a fieldbus communication standard, which uses a virtual token-passing medium-access-control mechanism. In this paper pre-run-time schedulability conditions for supporting real-time traffic with P-NET networks are established. Essentially, formulae to evaluate the upper bound of the end-to-end communication delay in P-NET messages are provided. Using this upper bound, a feasibility test is then provided to check the timing requirements for accessing remote process variables. This paper also shows how P-NET network segmentation can significantly reduce the end-to-end communication delays for messages with stringent timing requirements.

Estudo de Funcionalidades HTML5 para um Editor de Imagem na Internet

Hoje em dia existem múltiplas aplicações multimédia na Internet, sendo comum qualquer website apresentar mais de uma forma de visualização de informação além do texto como, por exemplo: imagens, áudio, vídeo e animação. Com aumento do consumo e utilização de Smartphone e Tablets, o volume de tráfego de internet móvel tem vindo a crescer rapidamente, bem como o acesso à internet através da televisão. As aplicações web-based ganham maior relevância devido à maior partilha ou consumo de conteúdos multimédia, com ou sem edição ou manipulação da mesma, através de redes sociais, como o Facebook. Neste documento é apresentado o estudo de alternativas HTML5 e a implementação duma aplicação web-based no âmbito do Mestrado de Engenharia Informática, ramo de Sistemas Gráficos e Multimédia, no Instituto Superior Engenharia do Porto (ISEP). A aplicação tem como objetivo a edição e manipulação de imagens, tanto em desktop como em dispositivos móveis, sendo este processo exclusivamente feito no lado do cliente, ou seja, no Browser do utilizador. O servidor é usado somente para o armazenamento da aplicação. Durante o desenvolvimento do projeto foi realizado um estudo de soluções de edição e manipulação de imagem existentes no mercado, com a respetiva análise de comparação e apresentadas tecnologias Web modernas como HTML5, CSS3 e JavaScript, que permitirão desenvolver o protótipo. Posteriormente, serão apresentadas, detalhadamente, as várias fases do desenvolvimento de um protótipo, desde a análise do sistema, à apresentação do protótipo e indicação das tecnologias utilizadas. Também serão apresentados os resultados dos inquéritos efetuados a um grupo de pessoas que testaram esse protótipo. Finalmente, descrever-se-á de forma mais exaustiva, a implementação e serão apontadas dificuldades encontradas ao longo do desenvolvimento, bem como indicadas futuras melhorias a introduzir.

Sistema per protegir la privadesa dels usuaris dels motors de cerca d'Internet

Actualment seria impensable la existència d'una xarxa d'informació com Internet sense la existència dels motors de cerca. Gràcies a ells, qualsevol usuari tenim al nostre abast la possibilitat d'obtenir informació sobre qualsevol tema només enviant una consulta des dels nostres ordinadors i rebent una resposta en qüestió de segons. Entre els usuaris dels cercadors d'Internet és molt habitual que les consultes facin referència a la empresa on treballem, la ciutat on vivim, els llocs que visitem, o inclús sobre problemes que tenim o malalties que patim amb l'objectiu de trobar opinions, consells o solucions. En resum, els usuaris, a través de les nostres consultes, proporcionem a diari als motors de cerca informació sobre nosaltres mateixos i sobre la nostra identitat que, juntament amb la adreça IP de la màquina des d'on fem les nostres consultes, ens fa perdre l'anonimat dins dels seus sistemes. Sobre aquesta problemàtica és del que tracta el present Projecte de Final de Carrera. En ell s'ha implementat una solució de la proposta especificada per Alexandre Viejo i Jordi Castellà-Roca en la seva publicació "Using social networks to disort users' profiles generated by web search engines", en la qual es documenten una sèrie de protocols de seguretat i d'algorismes de protecció i distribució que garanteixen la privacitat de la identitat dels usuaris dins dels motors de cerca aprofitant per aquest fi la relació existent entre aquests usuaris a través de les xarxes socials.

Sistema para proteger la privacidad de los usuarios de los motores de búsqueda de Internet

El sistema implementado utiliza las redes sociales para proteger la privacidad de los usuarios e impedir que los motores de búsqueda de Internet (WSE) elaboren un perfil de usuario. Sin embargo, los WSE serán capaces de elaborar un perfil distorsionado pero útil hasta un cierto nivel para poder proveer un servicio apropiado al usuario.

Use of the internet as a source of health information by Spanish adolescents

The Internet is a fundamental part of the daily life of adolescents, they consider it as a safe and confidential source of information on health matters. The aims is to describe the experience of Spanish adolescents searching for health information on the Internet. Methods A cross-sectional study of 811 school-age adolescents in Granada was carried out. An adapted and piloted questionnaire was used which was controlled by trained personnel. Sociodemographic and health variables were included together with those concerning the conditions governing access to and use of information and communication technologies (ICT). Results 811 adolescents were surveyed (99.38% response rate), mean age was 17 years old. Of these, 88% used the Internet; 57.5% used it on a daily or weekly basis and 38.7% used it occasionally. Nearly half the sample group (55.7%) stated that they used the Internet to search for health-related information. The main problems reported in the search for e-health were the ignorance of good web pages (54.8%) and the lack of confidence or search skills (23.2%). Conclusions In conclusion, it seems plausible to claim that websites designed and managed by health services should have a predominant position among interventions specifically addressed to young people.

Análisis de la producción científica visible en internet de los técnicos de salud ambiental del Servicio Andaluz de Salud

Internet it is a powerful interactive communication channel with world scope, through which can be multiplied the visibility of the research of the professionals whose scientific production has a difficult diffusion by the conventionals media. It is presented an analysis of the scientific publications observed in the web in order to understand the different communication processes accomplished by the superior corps of environmental health technical of the Andalusian Health Service. Using the nominal relationship of the professionals, we used Google ‘search engine’ for all scientific publications located in the internet; we were made different bibliometric indicators as of the recovered records and was analyzed the time evolution of the scientific production, documental categories, geografic distribution, language, coauthors and institutional collaboration. It was identified a growing trend in the productivity of the publications in the last decade, mainly through communications to congresses (70.4%) and journals articles (16.9%). The publications mainly are located in spanish journals, that they are indexed on national and international databases. In all the Andalusian provinces was identified some published scientific communication. The indicator of coauthors is very high (95.77%) although the institutional participation is limited mainly to the primary attention districts, occupational centers of each professional (85.21%). The scientific publication patterns visualized in the web represent an important contribution for the knowledge of the characteristics of the environmental health professionals of the Andalusian health service, what provides avaluable information for the support of the information systems in public health.

Redes sociales e internet: hacia la promoción de la salud 2.0

Boletín semanal para profesionales sanitarios de la Secretaría General de Salud Pública y Participación Social de la Consejería de Salud