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.

Abstract
In this paper, we present TIV.lib, an open-source library for the content-based tonal description of musical audio signals. Its main novelty relies on the perceptually-inspired Tonal Interval Vector space based on the Discrete Fourier transform, from which multiple instantaneous and global representations, descriptors and metrics are computed-e.g., harmonic change, dissonance, diatonicity, and musical key. The library is cross-platform, implemented in Python and the graphical programming language Pure Data, and can be used in both online and offline scenarios. Of note is its potential for enhanced Music Information Retrieval, where tonal descriptors sit at the core of numerous methods and applications.

Abstract
Computer programming plays a relevant role in the digital age as a key competency for project leverage and a driver of innovation for today's modern societies. Despite its importance, this domain is also well known for their higher learning failure rates. In this context, the study of how computer programming is taught is fundamental to clarify the teaching-learning process and to ensure the sharing of the best practices. This paper presents a survey on computer programming teaching in the first-year courses of Portuguese Universities, more precisely, what is taught and how it is taught. The study focuses essentially on the following facets: The class characterization, the methodologies used and the languages/technologies taught. Based on these criteria, a survey was done which gathers information of 59 courses included in a wide range of Universities spread across Portugal. The results were collected and analyzed. Based on this analysis a set of conclusions were taken revealing some interesting results on the teaching methods and languages used which can be useful to support a discussion on this subject and, consequently, to find new paths to shape the future of programming teaching. 2012 ACM Subject Classification Social and professional topics ! Computer science education.

Abstract
Chord progressions are core elements of Western tonal harmony regulated by multiple theoretical and perceptual principles. Ideally, objective measures to evaluate chord progressions should reflect their tonal fitness. In this work, we propose an objective measure of the fitness of a chord progression within the Western tonal context computed in the Tonal Interval Space, where distances capture tonal music principles. The measure considers four parameters, namely tonal pitch distance, consonance, hierarchical tension and voice leading between the chords in the progression. We performed a listening test to perceptually assess the proposed tonal fitness measure across different chord progressions, and compared the results with existing related models. The perceptual rating results show that our objective measure improves the estimation of a chord progression’s tonal fitness in comparison with existing models. © Springer Nature Switzerland AG 2020.