Bacterial inter-species communication mediated by the autoinducer-2 signal

Dissertation presented to obtain the Ph.D degree in Biology by Universidade Nova de Lisboa, Instituto de Tecnologia Química e Biológica, Instituto Gulbenkian de Ciência.

Including context in a routing algorithm for the internet of things

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia Informática

Outcomes of communication competence: A study on a Portuguese restaurant chain

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics

Using an LED as a sensor and visible light communication device in a smart illumination system

The need for more efficient illumination systems has led to the proliferation of Solid-State Lighting (SSL) systems, which offer optimized power consumption. SSL systems are comprised of LED devices which are intrinsically fast devices and permit very fast light modulation. This, along with the congestion of the radio frequency spectrum has paved the path for the emergence of Visible Light Communication (VLC) systems. VLC uses free space to convey information by using light modulation. Notwithstanding, as VLC systems proliferate and cost competitiveness ensues, there are two important aspects to be considered. State-of-the-art VLC implementations use power demanding PAs, and thus it is important to investigate if regular, existent Switched-Mode Power Supply (SMPS) circuits can be adapted for VLC use. A 28 W buck regulator was implemented using a off-the-shelf LED Driver integrated circuit, using both series and parallel dimming techniques. Results show that optical clock frequencies up to 500 kHz are achievable without any major modification besides adequate component sizing. The use of an LED as a sensor was investigated, in a short-range, low-data-rate perspective. Results show successful communication in an LED-to-LED configuration, with enhanced range when using LED strings as sensors. Besides, LEDs present spectral selective sensitivity, which makes them good contenders for a multi-colour LED-to-LED system, such as in the use of RGB displays and lamps. Ultimately, the present work shows evidence that LEDs can be used as a dual-purpose device, enabling not only illumination, but also bi-directional data communication.

A internet e o sistema de justiça

The subject of study of this Thesis aims to highlight and recognize as an object of reflection the undoubted relationship between the Internet and the Justice System, based on the issue of digital evidence. The simultaneously crossing of the juridical-legal implications and the more technical computer issues is the actual trigger for the discussion of the issues established. The Convention on Cybercrime of the Council of Europe of 23rd November 2001 and the Council Framework Decision n.° 2005/222/JHA of 24th February 2005 were avant-garde in terms of the international work about the crimes in the digital environment. In addition they enabled the harmonization of national legislations on the matter and, consequently, a greater flexibility in international judicial cooperation. Portugal, in compliance with these international studies, ratified, implemented and approved Law n. º 109/2009 of 15th September concerning the Cybercrime Act, establishing a more specific investigation and collection of evidence in electronic support when it comes to combating this type of crime, as it reinforced the Substantive Criminal Law and Procedural Nature. Nevertheless, the constant debates about the New Technologies of Information and Communication have not neglected the positive role of these tools for the user. However, they express a particular concern for their counterproductive effects; a special caution prevails on the part of the judge in assessing the digital evidence, especially circumstantial evidence, due to the its fragility. Indisputably, the practice of crimes through the computer universe, given its inexorable technical complexity, entails many difficulties for the forensic investigation, since the proofs hold temporary, changeable, volatile, and dispersed features. In this pillar, after the consummation of iter criminis, the Fundamental Rights of the suspects may be debated in the course of the investigation and the construction of iter probatorium. The intent of this Thesis is to contribute in a reflective way on the issues presented in order to achieve a bigger technical and legal awareness regarding the collection of digital proof, looking for a much lighter approach to its suitability in terms of evidentiary value.