Estudo de tecnologias dom��ticas e a sua aplica����o em projectos

Actualmente a ��rea da dom��tica (automa����o de casas e edif��cios) encontra-se em franca expans��o, com principal relev��ncia nos pa��ses mais desenvolvidos, com um crescimento de mercado de mais de 10% ao ano. Existem in��meras razoes para a crescente implanta����o da dom��tica em edif��cios, entre as quais a maior efici��ncia energ��tica, o aumento da seguran��a e a redu����o do custo de aquisi����o das tecnologias. No que diz respeito as habita����es particulares, acrescenta-se essencialmente o aumento do conforto devido ao grau de automa����o trazido pela dom��tica. Apesar da dom��tica n��o ser uma ��rea cientifico-tecnol��gica recente, a r��pida evolu����o das tecnologias associadas, nomeadamente a n��vel das redes de comunica����o com e sem fios, foi uma das razoes fundamentais para a elabora����o desta Tese. Acresce o facto de o candidato estar actualmente envolvido profissionalmente na ��rea, pelo qual esta Tese assume uma particular import��ncia. Realizou-se um estudo comparativo das tecnologias de dom��tica mais relevantes, escolhidas quer pelas suas caracter��sticas t��cnicas quer pela sua implanta����o de mercado e potencial futuro - KNX/EIB, LonWorks, HomePlug, ZigBee e Z-Wave. Destas, comprovou-se que as duas primeiras s��o aquelas que, actualmente, tem maior adequabilidade para serem aplicadas em projectos de dom��tica. Foi por isso efectuado um estudo mais elaborado das tecnologias LonWorks e KNX/EIB, incluindo a forma pratica de instala����o/programa����o, a elabora����o de dois demonstradores e de dois projectos (de acordo com um caderno de encargos real), usando as duas tecnologias. Concluiu-se que a tecnologia LonWorks apresenta vantagens no que respeita a escalabilidade (dimens��o) dos sistemas. Em termos futuros, prev��-se a necessidade da interoperabilidade entre os nos/redes cablados (tradicionais) com nos/redes sem fio, seguindo a tend��ncia para os ambientes inteligentes (���ambient intelligence/assisted living���, ���smart spaces���, ���ubiquitous computing).

Sistema sem fios para controlo de ilumina����o decorativa

Este projecto surgiu no contexto da solicita����o de um dos clientes da empresa Castros Ilumina����es que pretendia um sistema de ilumina����o decorativa (baseada em LED) de dois conjuntos de 288 janelas, pertencendo cada conjunto a uma fachada diferente do edif��cio. Este sistema teria que prever a possibilidade de controlar a cor de cada janela individualmente, dando ao cliente a possibilidade de alterar o ambiente decorativo das fachadas do edif��cio. A utiliza����o de comunica����o sem fios foi justificada pela necessidade de evitar a quantidade enorme de cabos que seria necess��rio passar utilizando os sistemas comerciais convencionais e a impossibilidade de os esconder. Esta solu����o foi pensada para ser implementada num edif��cio com 14 Andares, facto que por si s�� inviabiliza a passajem de cabos. Para interligar todos os dispositivos de ilumina����o decorativa com um controlador port��til, e eliminar os problemas ligados �� cablagem, foi utilizado o protocolo de comunica����es sem fios ZigBee���. A escolha recaiu neste protocolo devido a factores como os seus baixos consumos, simplicidade do protocolo comparativamente com outras redes e o seu baixo custo. No desenvolvimento deste projecto foi utilizada a stack da Microchip��, vers��o gratuita, disponibilizada na internet e os seus transceivers de comunica����o Zigbee���, MRF24j40MA. Para fazer a interface de comunica����o com o utilizador, foi desenvolvida uma aplica����o de Software para correr em computadores com ambiente Windows���. Esta aplica����o foi desenvolvida em Visual Studio��� utilizando a linguagem C#. Foram efectuados alguns testes para se perceber a efici��ncia e robustez da comunica����o ZigBee��� e apesar do n��mero de dispositivos dispon��veis para ensaios ser muito reduzido, foi poss��vel verificar que, mesmo funcionando correctamente, o desempenho do sistema poder�� ser melhorado, quer seja a n��vel da gest��o das comunica����es, quer a n��vel do software inform��tico para controlo do ambiente decorativo das fachadas do edif��cio. O sistema, no actual estado de desenvolvimento, permite controlar a cor dos v��rios dispositivos da rede atrav��s do computador, com uma resolu����o de 24bits. A aplica����o desenvolvida em Visual Studio��� permite controlar de forma simples e intuitiva para o utilizador, a cor do material iluminativo dos v��rios dispositivos da rede.

Controlador Boundary-Scan

A crescente complexidade dos sistemas electr��nicos associada a um desenvolvimento nas tecnologias de encapsulamento levou �� miniaturiza����o dos circuitos integrados, provocando dificuldades e limita����es no diagn��stico e detec����o de falhas, diminuindo drasticamente a aplicabilidade dos equipamentos ICT. Como forma de lidar com este problema surgiu a infra-estrutura Boundary Scan descrita na norma IEEE1149.1 ���Test Access Port and Boundary-Scan Architecture���, aprovada em 1990. Sendo esta solu����o tecnicamente vi��vel e interessante economicamente para o diagn��stico de defeitos, efectua tamb��m outras aplica����es. O SVF surgiu do desejo de incutir e fazer com que os fornecedores independentes inclu��ssem a norma IEEE 1149.1, �� desenvolvido num formato ASCII, com o objectivo de enviar sinais, aguardar pela sua resposta, segundo a m��scara de dados baseada na norma IEEE1149.1. Actualmente a incorpora����o do Boundary Scan nos circuitos integrados est�� em grande expans��o e consequentemente usufrui de uma forte implementa����o no mercado. Neste contexto o objectivo da disserta����o �� o desenvolvimento de um controlador boundary scan que implemente uma interface com o PC e possibilite o controlo e monitoriza����o da aplica����o de teste ao PCB. A arquitectura do controlador desenvolvido cont��m um m��dulo de Mem��ria de entrada, um Controlador TAP e uma Mem��ria de sa��da. A implementa����o do controlador foi feita atrav��s da utiliza����o de uma FPGA, �� um dispositivo l��gico reconfigur��veis constitu��do por blocos l��gicos e por uma rede de interliga����es, ambos configur��veis, que permitem ao utilizador implementar as mais variadas fun����es digitais. A utiliza����o de uma FPGA tem a vantagem de permitir a versatilidade do controlador, facilidade na altera����o do seu c��digo e possibilidade de inserir mais controladores dentro da FPGA. Foi desenvolvido o protocolo de comunica����o e sincroniza����o entre os v��rios m��dulos, permitindo o controlo e monitoriza����o dos est��mulos enviados e recebidos ao PCB, executados automaticamente atrav��s do software do Controlador TAP e de acordo com a norma IEEE 1149.1. A solu����o proposta foi validada por simula����o utilizando o simulador da Xilinx. Foram analisados todos os sinais que constituem o controlador e verificado o correcto funcionamento de todos os seus m��dulos. Esta solu����o executa todas as sequ��ncias pretendidas e necess��rias (envio de est��mulos) �� realiza����o dos testes ao PCB. Recebe e armazena os dados obtidos, enviando-os posteriormente para a mem��ria de sa��da. A execu����o do trabalho permitiu concluir que os projectos de componentes electr��nicos tender��o a ser descritos num n��vel de abstrac����o mais elevado, recorrendo cada vez mais ao uso de linguagens de hardware, no qual o VHDL �� uma excelente ferramenta de programa����o. O controlador desenvolvido ser�� uma ferramenta bastante ��til e vers��til para o teste de PCBs e outras funcionalidades disponibilizadas pelas infra-estruturas BS.

How new online communication tools and the availability of content influence the audiences and the creative process

We live in a changing world. At an impressive speed, every day new technological resources appear. We increasingly use the Internet to obtain and share information, and new online communication tools are emerging. Each of them encompasses new potential and creates new audiences. In recent years, we witnessed the emergence of Facebook, Twitter, YouTube and other media platforms. They have provided us with an even greater interactivity between sender and receiver, as well as generated a new sense of community. At the same time we also see the availability of content like it never happened before. We are increasingly sharing texts, videos, photos, etc. This poster intends to explore the potential of using these new online communication tools in the cultural sphere to create new audiences, to develop of a new kind of community, to provide information as well as different ways of building organizations��� memory. The transience of performing arts is accompanied by the need to counter that transience by means of documentation. This desire to ���save��� events reaches its expression with the information archive of the different production moments as well as the opportunity to record the event and present it through, for instance, digital platforms. In this poster we intend to answer the following questions: which online communication tools are being used to engage audiences in the cultural sphere (specifically between theater companies in Lisbon)? Is there a new relationship with the public? Are online communication tools creating a new kind of community? What changes are these tools introducing in the creative process? In what way the availability of content and its archive contribute to the organization memory? Among several references, we will approach the two-way communication model that James E. Grunig & Todd T. Hunt (1984) already presented and the concept of mass self-communication of Manuel Castells (2010). Castells also tells us that we have moved from traditional media to a system of communication networks. For Scott Kirsner (2010), we have entered an era of digital creativity, where artists have the tools to do what they imagined and the public no longer wants to just consume cultural goods, but instead to have a voice and participate. The creativity process is now depending on the public choice as they wander through the screen. It is the receiver who owns an object which can be exchanged. Virtual reality has encouraged the receiver to abandon its position of passive observer and to become a participant agent, which implies a challenge to organizations: inventing new forms of interfaces. Therefore, we intend to find new and effective online tools that can be used by cultural organizations; the best way to manage them; to show how organizations can create a community with the public and how the availability of online content and its archive can contribute to the organizations��� memory.

IEEE 802.15.4 for wireless sensor networks: a technical overview

Low-rate low-power consumption and low-cost communication are the key points that lead to the specification of the IEEE 802.15.4 standard. This paper overviews the technical features of the physical layer and the medium access control sublayer mechanisms of the IEEE 802.15.4 protocol that are most relevant for wireless sensor network applications. We also discuss the ability of IEEE 802.15.4 to fulfil the requirements of wireless sensor network applications.

Industrial ethernet: building blocks for a holistic approach

For industrial environments it is true that Ethernet technologies are there to stay. In fact, a number of characteristics are boosting the eagerness of extending Ethernet to also cover factory-floor applications. Fullduplex links, non-blocking and priority-based switching, bandwidth availability, just to mention a few, are characteristics upon which that eagerness is building up. But, will Ethernet technologies really manage to replace traditional field bus networks? Fieldbus fundamentalists often argue that the two things are not comparable. In fact, Ethernet technology, by itself, does not include features above the lower layers of the OSI communication model. Where are the higher layers and the application enablers that permit building real industrial applications? And, taking for free that they are available, what is the impact of those protocols, mechanisms and application models on the overall performance of Ethernet-based distributed factory-floor applications?

A communication support for real-time distributed computer controlled systems

In this paper, we analyse the ability of P-NET [1] fieldbus to cope with the timing requirements of a Distributed Computer Control System (DCCS), where messages associated to discrete events should be made available within a maximum bound time. The main objective of this work is to analyse how the network access and queueing delays, imposed by P-NET���s virtual token Medium Access Control (MAC) mechanism, affect the realtime behaviour of the supported DCCS.

Efficient aggregate computations in large-scale dense WSN

We focus on large-scale and dense deeply embedded systems where, due to the large amount of information generated by all nodes, even simple aggregate computations such as the minimum value (MIN) of the sensor readings become notoriously expensive to obtain. Recent research has exploited a dominance-based medium access control(MAC) protocol, the CAN bus, for computing aggregated quantities in wired systems. For example, MIN can be computed efficiently and an interpolation function which approximates sensor data in an area can be obtained efficiently as well. Dominance-based MAC protocols have recently been proposed for wireless channels and these protocols can be expected to be used for achieving highly scalable aggregate computations in wireless systems. But no experimental demonstration is currently available in the research literature. In this paper, we demonstrate that highly scalable aggregate computations in wireless networks are possible. We do so by (i) building a new wireless hardware platform with appropriate characteristics for making dominance-based MAC protocols efficient, (ii) implementing dominance-based MAC protocols on this platform, (iii) implementing distributed algorithms for aggregate computations (MIN, MAX, Interpolation) using the new implementation of the dominance-based MAC protocol and (iv) performing experiments to prove that such highly scalable aggregate computations in wireless networks are possible.

Using a prioritized MAC protocol to execute the database operation join in networked embedded computer systems

Database query languages on relations (for example SQL) make it possible to join two relations. This operation is very common in desktop/server database systems but unfortunately query processing systems in networked embedded computer systems currently do not support this operation; specifically, the query processing systems TAG, TinyDB, Cougar do not support this. We show how a prioritized medium access control (MAC) protocol can be used to efficiently execute the database operation join for networked embedded computer systems where all computer nodes are in a single broadcast domain.

H-NAMe: specifying, implementing and testing a hidden-node avoidance mechanism for wireless sensor networks

The hidden-node problem has been shown to be a major source of Quality-of-Service (QoS) degradation in Wireless Sensor Networks (WSNs) due to factors such as the limited communication range of sensor nodes, link asymmetry and the characteristics of the physical environment. In wireless contention-based Medium Access Control protocols, if two nodes that are not visible to each other transmit to a third node that is visible to the formers, there will be a collision ��� usually called hidden-node or blind collision. This problem greatly affects network throughput, energy-efficiency and message transfer delays, which might be particularly dramatic in large-scale WSNs. This technical report tackles the hidden-node problem in WSNs and proposes HNAMe, a simple yet efficient distributed mechanism to overcome it. H-NAMe relies on a grouping strategy that splits each cluster of a WSN into disjoint groups of non-hidden nodes and then scales to multiple clusters via a cluster grouping strategy that guarantees no transmission interference between overlapping clusters. We also show that the H-NAMe mechanism can be easily applied to the IEEE 802.15.4/ZigBee protocols with only minor add-ons and ensuring backward compatibility with the standard specifications. We demonstrate the feasibility of H-NAMe via an experimental test-bed, showing that it increases network throughput and transmission success probability up to twice the values obtained without H-NAMe. We believe that the results in this technical report will be quite useful in efficiently enabling IEEE 802.15.4/ZigBee as a WSN protocol.

Human-Human Collaboration in Virtual Teams

Extended and networked enterprises distribute the design of products, planning of the production process, and manufacturing regionally if not globally. Employees are therefore confronted with collaborative work over remote sites. A cost effective collaboration depends highly on the organization maintaining a common understanding for this kind of work and a suitable support with information and communication technology. The usual face to face work is going to be replaced at least partly if not totally by computer mediated collaboration. Creating and maintaining virtual teams is a challenge to work conditions as well as technology. New developments on cost-effective connections are providing not only vision and auditory perception but also haptic perception. Research results for improving remote collaboration are presented. Individual, social and cultural aspects are considered as new requirements on the employees of networked and extended enterprises.

Exploiting a prioritized MAC protocol to efficiently compute interpolations

Consider a network where all nodes share a single broadcast domain such as a wired broadcast network. Nodes take sensor readings but individual sensor readings are not the most important pieces of data in the system. Instead, we are interested in aggregated quantities of the sensor readings such as minimum and maximum values, the number of nodes and the median among a set of sensor readings on different nodes. In this paper we show that a prioritized medium access control (MAC) protocol may advantageously be exploited to efficiently compute aggregated quantities of sensor readings. In this context, we propose a distributed algorithm that has a very low time and message-complexity for computing certain aggregated quantities. Importantly, we show that if every sensor node knows its geographical location, then sensor data can be interpolated with our novel distributed algorithm, and the message-complexity of the algorithm is independent of the number of nodes. Such an interpolation of sensor data can be used to compute any desired function; for example the temperature gradient in a room (e.g., industrial plant) densely populated with sensor nodes, or the gas concentration gradient within a pipeline or traffic tunnel.

Exact analysis of TDMA with slot skipping

Consider a communication medium shared among a set of computer nodes; these computer nodes issue messages that are requested to be transmitted and they must finish their transmission before their respective deadlines. TDMA/SS is a protocol that solves this problem; it is a specific type of Time Division Multiple Access (TDMA) where a computer node is allowed to skip its time slot and then this time slot can be used by another computer node. We present an algorithm that computes exact queuing times for TDMA/SS in conjunction with Rate-Monotonic (RM) or Earliest- Deadline-First (EDF).

A simulation model for the IEEE 802.15.4 protocol: delay/throughput evaluation of the GTS mechanism

The IEEE 802.15.4 protocol has the ability to support time-sensitive Wireless Sensor Network (WSN) applications due to the Guaranteed Time Slot (GTS) Medium Access Control mechanism. Recently, several analytical and simulation models of the IEEE 802.15.4 protocol have been proposed. Nevertheless, currently available simulation models for this protocol are both inaccurate and incomplete, and in particular they do not support the GTS mechanism. In this paper, we propose an accurate OPNET simulation model, with focus on the implementation of the GTS mechanism. The motivation that has driven this work is the validation of the Network Calculus based analytical model of the GTS mechanism that has been previously proposed and to compare the performance evaluation of the protocol as given by the two alternative approaches. Therefore, in this paper we contribute an accurate OPNET model for the IEEE 802.15.4 protocol. Additionally, and probably more importantly, based on the simulation model we propose a novel methodology to tune the protocol parameters such that a better performance of the protocol can be guaranteed, both concerning maximizing the throughput of the allocated GTS as well as concerning minimizing frame delay.

The sociological perspective on the knowledge-based society: assumptions, facts and visions

The paper will present the central discourse of the knowledge-based society. Already in the 1960s the debate of the industrial society already raised the question whether there can be considered a paradigm shift towards a knowledge-based society. Some prominent authors already foreseen ���knowledge��� as the main indicator in order to displace ���labour��� and ���capital��� as the main driving forces of the capitalistic development. Today on the political level and also in many scientific disciplines the assumption that we are already living in a knowledge-based society seems obvious. Although we still do not have a theory of the knowledge-based society and there still exist a methodological gap about the empirical indicators, the vision of a knowledge-based society determines at least the perception of the Western societies. In a first step the author will pinpoint the assumptions about the knowledge-based society on three levels: on the societal, on the organisational and on the individual level. These assumptions are relied on the following topics: a) The role of the information and communication technologies; b) The dynamic development of globalisation as an ���evolutionary��� process; c) The increasing importance of knowledge management within organisations; d) The changing role of the state within the economic processes. Not only the differentiation between the levels but also the revision of the assumptions of a knowledge-based society will show that the ���topics raised in the debates��� cannot be considered as the results of a profound societal paradigm shift. However what seems very impressive is the normative and virtual shift towards a concept of modernity, which strongly focuses on the role of technology as a driving force as well as on the global economic markets, which has to be accepted. Therefore ��� according to the official debate - the successful adaptation of these processes seems the only way to meet the knowledge-based society. Analysing the societal changes on the three levels, the label ���knowledge-based society��� can be seen critically. Therefore the main question of Theodor W. Adorno during the 16th Congress of Sociology in 1968 did not loose its actuality. Facing the societal changes he asked whether we are still living in the industrial society or already in a post-industrial state. Thinking about the knowledge-based society according to these two options, this exercise would enrich the whole debate in terms of social inequality, political, economic exclusion processes and at least the power relationship between social groups.