Graph matching is a fundamental problem in pattern recognition, with many applications such as software analysis and computational biology. One well-known type of graph matching problem is graph isomorphism, which consists of deciding if two graphs are identical. Despite its usefulness, the properties that one may check using graph isomorphism are rather limited, since it only allows strict equality checks between two graphs. For example, it does not allow one to check complex structural properties such as if the target graph is an arbitrary length sequence followed by an arbitrary size loop. We propose a generalization of graph isomorphism that allows one to check such properties through a declarative specification. This specification is given in the form of a Regular Graph Pattern (ReGaP), a special type of graph, inspired by regular expressions, that may contain wildcard nodes that represent arbitrary structures such as variable-sized sequences or subgraphs. We propose a SAT-based algorithm for checking if a target graph matches a given ReGaP. We also propose a preprocessing technique for improving the performance of the algorithm and evaluate it through an extensive experimental evaluation on benchmarks from the CodeSearchNet dataset.

Visual Programming Languages (VPLs), coupled with the high-level abstractions that are commonplace in visual programming environments, enable users with less technical knowledge to become proficient programmers. However, the lower skill floor required by VPLs also entails that programmers are more likely to not adhere to best practices of software development, producing systems with high technical debt, and thus poor maintainability. Duplicated code is one important example of such technical debt. In fact, we observed that the amount of duplication in the OutSystems VPL code bases can reach as high as 39%.

Ensuring constant synchronicity between the IT Architecture (ITA) and the actual Information Systems (IS) without the help of automatic tools is an intractable task, especially when taking into account modern IS' rapid evolution and growing complexity and distributed nature. We propose an automatic AS-IS ITA verification methodology and framework based on deep passive network traffic analysis and logical inference rules with the goal of inferring relevant facts about the actual ITA. The resulting knowledge is described according to a conceptual model designed for this purpose. We also propose an organization-independent mapping relationship between that ITA network evidence model and an ISA modeling framework (CEO Framework), at the technology (ITA) level, realized through a set of logical deduction rules. These rules formally define the conditions that must hold between the inferred evidence and a high-level ITA model (both represented in this inference system) in order to declare that model factual and in line with reality. It is the automatic execution of these rules that realizes the verification process that reports, as a result, all the significant detected discrepancies. The proposed concepts and methodology are implemented in a prototype applied to a case study in the leading Portuguese Telecom operator. The proposed solution was shown to be capable of successfully verifying the case study's ITA model as well as discovering new, undocumented, information through logical inference.