Abstract
Counters are an important abstraction in distributed computing, and play a central role in large scale geo-replicated systems, counting events such as web page impressions or social network likes. Classic distributed counters, strongly consistent via linearisability or sequential consistency, cannot be made both available and partition-tolerant, due to the CAP Theorem, being unsuitable to large scale scenarios. This paper defines Eventually Consistent Distributed Counters (ECDCs) and presents an implementation of the concept, Handoff Counters, that is scalable and works over unreliable networks. By giving up the total operation ordering in classic distributed counters, ECDC implementations can be made AP in the CAP design space, while retaining the essence of counting. Handoff Counters are the first Conflict-free Replicated Data Type (CRDT) based mechanism that overcomes the identity explosion problem in naive CRDTs, such as G-Counters (where state size is linear in the number of independent actors that ever incremented the counter), by managing identities towards avoiding global propagation and garbage collecting temporary entries. The approach used in Handoff Counters is not restricted to counters, being more generally applicable to other data types with associative and commutative operations.

Abstract
Information can be conveyed to the user by means of a narrative, modeled according to the user’s context. A case in point is the weather, which can be perceived differently and with distinct levels of importance according to the user’s context. For example, for a blind person, the weather is an important element to plan and move between locations. In fact, weather can make it very difficult or even impossible for a blind person to successfully negotiate a path and navigate from one place to another. To provide proper information, narrated and delivered according to the person’s context, this paper proposes a project for the creation of weather narratives, targeted at specific types of users and contexts. The proposal’s main objective is to add value to the data, acquired through the observation of weather systems, by interpreting that data, in order to identify relevant information and automatically create narratives, in a conversational way or with machine metadata language. These narratives should communicate specific aspects of the evolution of the weather systems in an efficient way, providing knowledge and insight in specific contexts and for specific purposes. Currently, there are several language generator’ systems, which automatically create weather forecast reports, based on previously processed and synthesized information. This paper, proposes a wider and more comprehensive approach to the weather systems phenomena, proposing a full process, from the raw data to a contextualized narration, thus providing a methodology and a tool that might be used for various contexts and weather systems. © 2019, Springer Nature Switzerland AG.

Abstract
Although Finite-State Automata (FSA) have been successfully used in modeling and control of Discrete Event Systems (DESs), they are limited to represent complex and advanced features of DESs, such as context recognition and switching. The literature has suggested that a FSA can nevertheless be enriched with parameters properly collected from the modeled system, so that this favors design and control. A parameter can be embedded either on transitions or states. However, each approach is structured within a specific framework, so that their comparison and integration are not straightforward and they may lead to different control solutions, modeled, computed and implemented using distinct strategies. In this paper, we show how to combine advantages from parameters in modeling and control of DESs. Each approach is structured and their advantages are identified and exemplified. Then, we propose a conversion method that allows to translate a design-friendly model into a synthesis-efficient structure. Examples illustrate the approach. © 2019 IEEE.

Abstract
To contribute in filling in the gap regarding experiences targeted at and evaluated by teenagers in museums, we involved 78 teenagers aged 16-19 to test three different gamified tours developed by cultural heritage professionals from the Natural History Museum of Funchal, Portugal. The digital tours can be described as follows: 1) expositive - through which teens become aware of a scientific library in the museum; 2) gastronomic - teens are exposed to curiosities and recipes regarding a selection of marine species exhibited in the museum; 3) digital manipulation manipulated characters (image and voice) guide the visitor through videos of the marine species in their natural habitats. We report on measuring the teenagers' overall experience with each of the prototypes, particularly their engagement with the exhibition, the usefulness and usability of the prototypes, as well as their feelings and emotions at the end of each tour. We report on lessons learned from the evaluation of these prototypes as well as which approaches and mechanics engaged the teens the most.

Abstract
IDEs are environments specialized in support during the development of programs. They contain several utilities to code, run, debug, and deploy programs quickly. However, they do not provide the automatic assessment of programming exercises, which is required in both learning and competitive programming environment. Therefore, IDEs are often underestimated in these contexts and replaced by basic code editors. Yet, IDEs have unique features which are essential for programmers, such as the debugger or the package explorer. This paper presents Raccode, a plugin for assessment of programming exercises in Eclipse. This plugin integrates with Mooshak to combine the diverse capabilities of an IDE, like Eclipse, with the automatic evaluation of exercises, clarification requests, printouts, balloons, and rankings. It can be used both in competitive and learning environments. The paper describes Raccode, its concept, architecture and design. © André Silva, José Paulo Leal, and José Carlos Paiva.

Abstract
New virtual reality technologies allow the user to gain a greater sense of presence in virtual environments. One of the areas where these technologies can have a major impact is the area of games that allow users to explore these environments and interact with them by receiving feedback from their actions in real time. The present study aimed to evaluate if the use of physiological signals to update the virtual environment in real-time could be used to increase the feeling of presence. To perform this study, an experimental study was designed based on a game that allowed the use of physiological data to calculate the participant's arousal in real-time and, based on that, modify certain elements of the virtual environment where the participants were asked to fulfill a task. With the analysis of the data obtained, it was possible to verify that the use of biofeedback did not reveal statistically significant differences for the variables tested, however, it can be concluded that the use of biofeedback improves some subscales of presence, being the users with more experience in games and more computer knowledge susceptible to such changes.