Abstract
Automatic grading based on unit tests is a key feature of massive open online courses (MOOC) on programming, as it allows instant feedback to students and enables courses to scale up. This technique works well for sequential programs, by checking outputs against a sample of inputs, but unfortunately it is not adequate for detecting races and deadlocks, which precludes its use for concurrent programming, a key subject in parallel and distributed computing courses. In this paper we provide a hands-on evaluation of verification and testing tools for concurrent programs, collecting a precise set of requirements, and describing to what extent they can or can not be used for this purpose. Our conclusion is that automatic grading of concurrent programming exercises remains an open challenge.

Abstract
Aim There has been an increase in the development of technologies that can deliver personalised dietary advice. Devising healthy, sustainable dietary plans will mean taking into consideration extrinsic factors such as individual social circumstances. The aim of this study was to identify societal groups more or less receptive to and likely to engage with personalised nutrition initiatives. Sample and methods Volunteers were recruited via a social research agency from within the UK. The resultant sample (N = 1061) was 49% female, aged 18-65 years. Results MANOVA (Tukey HSD applied) indicated that females and younger people (aged 18-29 years) had more favourable attitudes and were more likely to intend to adopt personalised nutrition. There were no differences in attitude toward or intention to adopt personalised nutrition between different education levels, income brackets or occupational groups. Conclusion These results imply that females and younger people may be most likely to adopt personalised nutrition in the future. Initiatives to promote healthy eating should target males and older people.

Abstract
The services supporting the websites, both public and private entities, may support security protocols such as HTTPS or DNSSEC. Public and private entities have a responsibility to ensure the security of their online platforms. Entities in the public domain such as city councils provide their services through their websites. However, each city council has its systems, configurations, and IT teams, and this means they have different standings regarding the security protocols supported. This paper analyzes the status of security protocols on Portuguese city council websites, specifically HTTPS and DNSSEC. The study evaluated 308 city council websites using a script developed for the research, and data was collected from the website of Direcao Geral das Autarquias Locais (DGAL) on December 14, 2022, and the websites were scanned on December 22, 2022. The results of this assessment reveal that around 97% of city council websites use RSA as their encryption algorithm and around 84% use 2048-bit length keys for digital certificate signing. Furthermore, about 53% of the city council websites are still supporting outdated and potentially insecure SSL/TLS versions, and around 95% of the councils are not implementing DNSSEC in their domains. These results highlight potential areas for improvement in cybersecurity measures and can serve as a baseline to track progress toward improving cybersecurity maturity in Portuguese city councils.

Abstract
Extreme Learning Machines (ELMs) are a versatile Machine Learning (ML) algorithm that features as the main advantage the possibility of a seamless implementation with physical systems. Yet, despite the success of the physical implementations of ELMs, there is still a lack of fundamental understanding in regard to their optical implementations. In this context, this work makes use of an optical complex media and wavefront shaping techniques to implement a versatile optical ELM playground to gain a deeper insight into these machines. In particular, we present experimental evidences on the correlation between the effective dimensionality of the hidden space and its generalization capability, thus bringing the inner workings of optical ELMs under a new light and opening paths toward future technological implementations of similar principles.

Abstract
Boarding time constitutes a critical element of turnaround time, which is used to measure the efficiency of airline operations. Therefore, to reduce boarding time, it is imperative to reconsider traditional passenger boarding strategies to make them more efficient. In this sense, this study seeks to analyze the impact of different strategies on boarding times using discrete event simulation on an Airbus 320. Seven boarding strategies have been identified and considered in our study, as follows: random, back-to-front, outside-in, reverse pyramid, blocks, Steffen, and modified optimal. The impact of carrying hand luggage and the presence of priority passengers has been considered, as well as the impact of having a continuous arrival of passengers during the boarding process versus having all passengers available at boarding time. In general, simulation results have pointed out that the outside-in and reverse pyramid strategies are the most effective, improving boarding time by up to 15%, when compared to the random strategy. Moreover, the back-to-front strategy, which is generally implemented by airline companies, has been shown to be the most inefficient strategy. Efficient boarding strategies are expected to contribute to the sustainability of air travel by minimizing the turnaround time, improving operational efficiency, and reducing emissions.

Abstract
A Bloom Filter is a probabilistic data structure designed to check, rapidly and memory-efficiently, whether an element is present in a set. It has been vastly used in various computing areas and several variants, allowing deletions, dynamic sets and working with sliding windows, have surfaced over the years. When summarizing data streams, it becomes relevant to identify the more recent elements in the stream. However, most of the sliding window schemes consider the most recent items of a data stream without considering time as a factor. While this allows, e.g., storing the most recent 10000 elements, it does not easily translate into storing elements received in the last 60 seconds, unless the insertion rate is stable and known in advance. In this paper, we present the Time-limited Bloom Filter, a new BF-based approach that can save information of a given time period and correctly identify it as present when queried, while also being able to retire data when it becomes stale. The approach supports variable insertion rates while striving to keep a target false positive rate. We also make available a reference implementation of the data structure as a Redis module.