Abstract
We study the electromagnetically induced transparency (EIT) phenomenon in a hollow-core fibre filled with rubidium gas. We analyse the impact of the guiding effect and of the temperature on the properties of the EIT phenomenon. The refractive index felt by the probe laser is found to vary due to the radial dependence of the fibre mode field at the pump frequency. Several results are presented for the transmission, dispersion, and group velocity of the probe field, considering both the free propagation regime and the guided propagation along the hollow-core fibre. We note that the EIT occurring in a waveguide has a great potential for practical applications since it can be controlled by adjusting the gas and the fibre properties.

Abstract
Telecommunication networks evolution is driving the development of new applications for mobile devices. Some of these applications are resource-intensive and push computational and energy demands of mobile devices beyond the mobile hardware capabilities. In this context, Mobile Cloud Computing (MCC) architecture emerges as a solution for offloading mobile devices that allows to execute these applications in cloud datacenters thus reducing the processing demand in mobile devices. However, more demanding applications, e.g. interactive and realtime applications, are sensitive to processing and communications delay. For these applications, Mobile Edge Computing (MEC) can be used as an intermediary technology, providing computing and storage resources in the network edge. This paper presents a study carried out to evaluate the performance of MEC and MCC architectures when executing two applications, Fluid and FaceSwap, representative of real time and computing intensive applications. A set of scenarios were designed to quantify the performance of these architectures in different settings.

Abstract
Prompting students' interest and engagement in learning environments is crucial to achieve the best results. Academia and educators in general are constantly adapting materials and methodologies in order to maximise the acquisition of contents by their students. In this case-study, a new teaching/learning methodology is presented and evaluated through a final questionnaire survey. This case-study aims to understand students' efficiency and motivation levels regarding a new teaching/learning methodology adopted in the second module of a Computer Systems and Architectures course attended by first-year Computer Sciences undergraduates. The new teaching/learning methodology relies on a specific programming language-ARMv6 assembly-to improve students' efficiency levels, and an innovative always-visible in-class mobile test scenario, implemented through a low-cost computing platform-Raspberry Pi 1 B+- A s a server, mimicking as much as possible a real-life environment, so that students believe they are working on real hardware, thus enhancing their motivation levels. The results of the questionnaire survey allowed to infer that the use of a specific programming language, such as ARMv6 assembly, coupled with a new always-visible in-class mobile test scenario were in fact efficient in raising the levels of motivation among Computer Sciences students and, consequently, improved their skills in Computer Architecture. 2012 ACM Subject Classification Computer systems organization.

Abstract
Payments using cryptocurrencies may require that the user is able to provide proof of ownership and proof of provenance for a specific transaction. In this paper an innovative web based solution is proposed as a framework that issues reports, on request, pertaining proof of ownership and proof of provenance. The proposed framework provides proof of ownership by using micro-payments and, when used recursively, it can produce provenance reports up to a defined granularity level of transactions. A proof of concept prototype of the proposed framework was implemented and its operation and output is presented and explained. Some limitations and future work directions are also identified. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2020.

Abstract
Radio-Frequency IDentification (RFID) technologies have been widely used in physical ID cards in educational institutions due to its low-cost, simple integration and convenience. In a university campus, the RFID technology can be used for proximity-based authentication for services such as access control, student/employee attendance record, or in-campus payments. These RFID-based technologies present vulnerabilities that, if exploited, can compromise the university campus authentications systems. RFID skimming and tag killing are examples of attacks that are simple to execute and have a high impact on their victims. This paper exploits a tag-related vulnerability of an ID Card based on RFID technology for proximity-based authentication inside a university campus. The proof of concept presented shows that, by using low-cost commercial-off-the-shelf hardware and open-source software, it is simple to clone an ID card and perform RFID skimming, harming the real ID card users. Possible countermeasures are later introduced and discussed.

Abstract
A evolução das redes de telecomunicações tem promovido o desenvolvimento de novas aplicações para dispositivos móveis. Algumas destas aplicações exigem requisitos computacionais e energéticos que vão para além das capacidades dos dispositivos móveis. Neste contexto, pode ser utilizada a arquitetura Mobile Cloud Computing (MCC), que permite executar as aplicações em datacenters na cloud e aliviar o processamento nos dispositivos móveis. No entanto, algumas aplicações mais exigentes, e.g. interativas e de tempo real, são mais sensíveis ao atraso no processamento e comunicação da informação. Para estas aplicações, a arquitetura Mobile Edge Computing (MEC) pode ser utilizada como uma tecnologia intermédia que disponibiliza recursos computacionais e de armazenamento a partir da periferia da rede. Este artigo apresenta um estudo que avalia o desempenho das arquiteturas MCC e MEC na execução de duas aplicações tomadas como representativas do espectro das aplicações interativas, de tempo real e de processamento intensivo: o Fluid e o FaceSwap. São apresentados resultados que permitem quantificar o desempenho destas arquiteturas em diferentes circunstâncias.;Telecommunication networks evolution is driving the development of new applications for mobile devices. Some of these applications are resource-intensive and push computational and energy demands of mobile devices beyond the mobile hardware capabilities. In this context, Mobile Cloud Computing (MCC) architecture emerges as a solution for offloading mobile devices that allows to execute these applications in cloud datacenters thus reducing the processing demand in mobile devices. However, more demanding applications, e.g. interactive and real-time applications, are sensitive to processing and communications delay. For these applications, Mobile Edge Computing (MEC) can be used as an intermediary technology, providing computing and storage resources in the network edge. This paper presents a study carried out to evaluate the performance of MEC and MCC architectures when executing two applications, Fluid and FaceSwap, representative of real time and computing intensive applications. A set of scenarios were designed to quantify the performance of these architectures in different settings.