25 documents found, page 1 of 3
Plagiarism detection: A tool survey and comparison
Martins, Vítor T.; Fonte, Daniela; Henriques, Pedro Rangel; Cruz, Daniela daWe illustrate the state of the art in software plagiarism detection tools by comparing their features and testing them against a wide range of source codes. The source codes were edited according to several types of plagiarism to show the tools accuracy at detecting each type. The decision to focus our research on plagiarism of programming languages is two fold: on one hand, it is a challenging case-study since...
Partial correctness and continuous integration in computer supported education
Fonte, Daniela; Vilas Boas, Ismael; Oliveira, Nuno; Cruz, Daniela da; Gançarski, Alda Lopes; Henriques, Pedro RangelIn this paper we support the idea that students and teachers will benefit from a computer-based system that assesses programming exercises and provide immediate and detailed feedback: students would be able to evolve in the right direction and teachers would follow and assess more fairly their students. This assessment should outperform the typical right/wrong evaluation returned by existing tools, allowing for...
GuessXQ, a query-by-example approach for XML querying
Fonte, Daniela; Cruz, Daniela da; Henriques, Pedro Rangel; Gançarski, Alda LopesXML is a wide used general-purpose annotation formalism for creating custom markup languages. XML annotations give structure to plain documents to interpret their content. To extract information from XML documents XPath and XQuery languages can be used. However, the learning of these dialects requires a considerable effort. In this context, the traditional Query-By-Example methodology (for Relational Databases)...
A flexible dynamic system for automatic grading of programming exercises
Fonte, Daniela; Cruz, Daniela da; Gançarski, Alda Lopes; Henriques, Pedro RangelThe research on programs capable to automatically grade source code has been a subject of great interest to many researchers. Automatic Grading Systems (AGS) were born to support programming courses and gained popularity due to their ability to assess, evaluate, grade and manage the students’ programming exercises, saving teachers from this manual task. This paper discusses semantic analysis techniques, and how...
Interactive verification of safety-critical software
Cruz, Daniela da; Henriques, Pedro Rangel; Pinto, Jorge SousaA central issue in program verification is the generation of verification conditions (VCs): proof obligations which, if successfully discharged, guarantee the correctness of a program vis-a`-vis a given specification. While the basic theory of program verification has been around since the 1960s, the late 1990s saw the advent of practical tools for the verification of realistic programs, and research in this ar...
Program analysis and evaluation using QUIMERA
Fonte, Daniela; Vilas Boas, Ismael; Cruz, Daniela da; Gançarski, Alda Lopes; Henriques, Pedro RangelDuring last years, a new challenge rose up inside the programming communities: the programming contests. Programming contests can vary slightly in the rules but all of them are intended to assess the competitor skills concerning the ability to solve problems using a computer. These contests raise up three kind of challenges: to create a nice problem statement (for the members of the scientific committee); to so...
Assertion-based slicing and slice graphs
Barros, José Bernardo; Cruz, Daniela da; Henriques, Pedro Rangel; Pinto, Jorge SousaThis paper revisits the idea of slicing programs based on their axiomatic semantics, rather than using criteria based on control/data dependencies. We show how the forward propagation of preconditions and the backward propagation of postconditions can be combined in a new slicing algorithm that is more precise than the existing specification-based algorithms. The algorithm is based on (i) a precise test for rem...
Verification conditions for single-assignment programs
Cruz, Daniela da; Frade, M. J.; Pinto, Jorge SousaA mechanism for generating verification conditions (VCs) for the iteration-free fragment of an imperative language is fundamental in any deductive program verification system. In this paper we revisit symbolic execution, weakest preconditions, and bounded model checking as VC-generation mechanisms, and propose a uniform presentation of the corresponding sets of VCs, in terms of (logical encodings of) paths in t...
Automatic test generation for space
Costa, Ulisses Araújo; Cruz, Daniela da; Henriques, Pedro RangelThe European Space Agency (ESA) uses an engine to perform tests in the Ground Segment infrastructure, specially the Operational Simulator. This engine uses many different tools to ensure the development of regression testing infrastructure and these tests perform black-box testing to the C++ simulator implementation. VST (VisionSpace Technologies) is one of the companies that provides these services to ESA and ...
Problem domain oriented approach for program comprehension
Pereira, Maria João Tinoco Varanda; Marcelo Berón, Mario; Cruz, Daniela da; Oliveira, Nuno; Henriques, Pedro RangelThis paper is concerned with an ontology driven approach for Program Comprehension that starts picking up concepts from the problem domain ontology, analyzing source code and, after locating problem concepts in the code, goes up and links them to the programming language ontology. Different location techniques are used to search for concepts embedded in comments, in the code (identifier names and execution trac...