Program slicing is a program analysis technique to identify the parts of a program that can influence the values computed at a given program point. Its application to concurrent programs with shared memory revealed a new program dependence between threads called interference and uncovered some problems associated with concurrent executions such as time travel. To solve these problems, a new program representation for slicing concurrent programs was proposed: the threaded System Dependence Graph (tSDG), which aimed at solving the time travel problem and to provide context-sensitive slices for concurrent programs. In this paper, we show that the problem remains unsolved because the tSDG is not context-sensitive in some situations. We give a counterexample for the tSDG and identify situations where the tSDG is imprecise, generating context-insensitive slices for concurrent programs. To solve these imprecisions, we redesign the tSDG to become context-sensitive in those situations, solving the inaccuracy problem and preserving the solution to time travel. The new program representation is always as precise as the previous tSDG, and sometimes it is more precise. That is, the slices computed with the new graph are always smaller or equal than those computed with the previous tSDG.

Context: Petri net slicing is a technique to reduce the size of a Petri net to ease the analysis or understanding of the original Petri net. Objective: Presenting two new Petri net slicing algorithms to isolate those places and transitions of a Petri net (the slice) that may contribute tokens to one or more places given (the slicing criterion). Method: The two algorithms proposed are formalized. The maximality of the first algorithm and the minimality of the second algorithm are formally proven. Both algorithms, together with three other state-of-the-art algorithms, have been implemented and integrated into a single tool so that we have been able to carry out a fair empirical evaluation. Results: Besides the two new Petri net slicing algorithms, a public, free, and open-source implementation of five algorithms is reported. The results of an empirical evaluation of the new algorithms and the slices they produce are also presented. Conclusions: The first algorithm collects all places and transitions that may contribute tokens (in any computation) to the slicing criterion, while the second algorithm collects the places and transitions needed to fire the shortest transition sequence that contributes tokens to some place in the slicing criterion. Therefore, the net computed by the first algorithm can reproduce any computation that contributes tokens to any place of interest. In contrast, the second algorithm loses this possibility, but it often produces a much more reduced subnet (which still can reproduce some computations that contribute tokens to some places of interest). The first algorithm is proven maximal, and the second one is proven minimal.

Engineering education is facing many challenges: a decline in core mathematical skills; lowering entry requirements; and the diversity of the student cohort. One approach to confronting these challenges is to make subject content appropriate to the communication styles of today's student. To achieve this, a pedagogical shift from the traditional hierarchical approach to learning to one that embraces the use of technology as a tool to enhance the student learning experience is required. By including the student as co-creator of course content, a greater sense of engagement is achieved and a change to one where students become agents of their own learning is realized. This active learning constructivist approach shifts the focus from content delivery by the lecturer to active engagement with content by the student and in doing so provides an environment of achievement and ownership which empowers the student and increases self-efficacy. The online platform comprises a set of multiple choice questions focused on core mathematical concepts. The quizzes are constructed to adapt to student responses with custom video feedback created by their peers. This paper outlines the methodology followed and provides results of its evaluation in terms of student's perceptions.

This position paper defends the opinion that the distance of students to the professor in the classroom is directly related to their grades. This opinion is based on the results obtained in a large experiment performed during two academic years in various degrees, courses and semesters of two engineering schools. The experiment collected and processed data about the distribution of students in lectures and their final grades. Our results quantitatively confirm that grades can vary up to 14% depending on the distance to the professor.

This poster presents ongoing work that studies the influence of classmates over students' grades. We want to analyze different students habits and empirically quantify how they influence their academic performance. In particular, we want to answer the following questions: Do best/worst students sit together? Do students who sit alone get better grades than those who sit in pairs?

This paper describes SOC, a program slicer for CSP specifications. In order to increase the precision of program slicing, SOC uses a new data structure called Context-sensitive Synchronized Control Flow Graph (CSCFG). Given a CSP specification, SOC generates its associated CSCFG and produces from it two different kinds of slices; which correspond to two different static analyses. We present the tool's architecture, its main applications and the results obtained from experiments conducted in order to measure the performance of the tool.

The aim of this work is the modeling and verification of concurrent systems subject to dynamic changes using extensions of Petri nets. We begin by introducing the notion of net rewriting system. In a net rewriting system, a system configuration is described as a Petri net and a change in configuration is described as a graph rewriting rule. We show that net rewriting systems are Turing powerful, that is, the basic decidable properties of Petri nets are lost and, thus, automatic verification in not possible for this class. A subclass of net rewriting systems are reconfigurable Petri nets. In a reconfigurable Petri net, a change in configuration amounts to the modification of the flow relations of the places in the domain of the involved rule according to this rule, independently of the context in which this rewriting applies. We show that reconfigurable Petri nets are formally equivalent to Petri nets. This equivalence ensures that all the fundamental properties of Petri nets are still decidable for reconfigurable Petri nets and this model is thus amenable to automatic verification tools. Therefore, the expressiveness of both models is the same, but, with reconfigurable Petri nets, we can easily and directly model systems that change their structure dynamically.