Abstract
Counting subgraph occurrences is a hard but very important task in complex network analysis, with applications in concepts such as network motifs or graphlet degree distributions. In this paper we present a novel approach for this task that takes advantage of knowing that a large fraction of subgraph types does not appear at all on real-world networks. We describe a pattern-growth methodology that is able to iteratively build subgraph patterns that do not contain smaller non-occurring subgraphs, significantly pruning the search space. By using the g-trie data structure, we are able to efficiently only count those subgraphs that we are interested in, reducing the total computation time. The obtained experimental results are very promising allowing us to avoid the computation of up to 99.78% of all possible subgraph patterns. This showcases the potential of this approach and paves the way for reaching previously unattainable subgraph sizes. © Springer Nature Switzerland AG 2019.

Abstract

Abstract
Solving programming exercises is the best way to promote practice in computer programming courses and, hence, to learn a programming language. Meanwhile, programming courses continue to have an high rate of failures and dropouts. The main reasons are related with the inherent domain complexity, the teaching methodologies, and the absence of automatic systems with features such as intelligent authoring, profile-based exercise sequencing, content adaptation, and automatic evaluation on the student's resolution. At the same time, gamification is being used as an approach to engage learners' motivations. Despite its success, its implementation is still complex and based on ad-hoc and proprietary solutions. This paper presents PROud as a framework to inject gamification features in computer programming learning environments based on the usage data from programming exercises. This data can be divided into two categories: generic data produced by the learning environmentsuch as, the number of attempts and the duration that the students took to solve a specific exerciseor code-specific data produced by the assessment toolsuch as, code size, use memory, or keyword detection. The data is gathered in cloud storage and can be consumed by the learning environment through the use of a client library that communicates with the server through an established Application Programming Interface (API). With the fetched data, the learning environment can generate new gamification assets (e.g., leaderboards, quests, levels) or enrich content adaptations and recommendations in the inner components such as the sequencing tools. The framework is evaluated on its usefulness in the creation of a gamification asset to present dynamic statistics on specific exercises.

Abstract
Computer programming is a difficult subject that can only be mastered with lots of practice. It is therefore of primary importance to rise and retain students' engagement during a programming course, a task in which gamification has been proven as a competent method. Even though there are numerous reports on applying gamification to programming courses, there are no available open resources or dedicated platforms that could be used by programming teachers to gamily their courses, meeting both the requirements of being easy to adopt and leaving the decisions on the scope of the course and the level of gamification to the teachers themselves. In order to fulfill this gap, a consortium of four European institutions initiated a common project to develop open gamified programming exercises and interactive course materials for popular programming languages. In this paper, we report the results of the first stage of this work, which defined the range of gamification concepts to be covered within the developed framework and its evaluation by students.

Abstract
The architectural pattern of micro-services is being increasingly adopted by developers, facilitating the maintenance and scalability of the systems’ code. The adoption and consumption of these micro-services are often seen on the front-end code of the Web applications. Nevertheless, this adoption obliges web designers/developers to know where to look for those web services, to read their documentation and to write the request/response code as well to control the corresponding UI rendering. This whole process is time-consuming and error-prone. This article introduces SeCoGen as an interactive code generator for Web service parsing and consumption. The generator benefits from an HTTP request template, a query normalizer and dynamic UI templates. In order, to validate the generator feasibility and usefulness, a REST API to search for countries is used. © Ricardo Queirós.

Abstract
JavaScript is currently one of the most popular languages worldwide. Its meteoric rise is mainly due to the fact that the language is no longer bound to the limits of the browser and can now be used on several platforms. This growth has led to its increasing use by companies and, consequently, to become part of the curriculum in schools. Meanwhile, in the teaching-learning process of computer programming, teachers continue to use automatic code evaluation systems to relieve their time-consuming and error prone evaluation work. However, these systems reveal a number of issues: they are very generic (one size fits all), they have scarce features to foster exercises authoring, they do not adhere to interoperability standards (e.g. LMS communication), they rely solely on remote evaluators being exposed to single point of failure problems and reducing application performance and user experience, which is a feature well appreciated by the mobile users. In this context, LearnJS is presented as a Web playground for practicing the JavaScript language. The system uses a local evaluator (the user’s own browser) making response times small and thus benefiting the user experience. LearnJS also uses a sophisticated authoring system that allows the teacher to quickly create new exercises and aggregate them into gamified activities. Finally, LearnJS includes universal LMS connectors based on international specifications. In order to validate its use, an evaluation was made by a group of students of Porto Polytechnic aiming to validate the usability of its graphical user interface. © Ricardo Queirós.