Contracts are legally binding and enforceable agreements among two or more parties that govern social interactions. They have been used for millennia, including in commercial transactions, employment relationships and intellectual property generation. Each contract determines obligations and powers of contracting parties. The execution of a contract needs to be continuously monitored to ensure compliance with its terms and conditions. Smart contracts are software systems that monitor and control the execution of contracts to ensure compliance. But for such software systems to become possible, contracts need to be specified precisely to eliminate ambiguities, contradictions, and missing clauses. This thesis proposes a formal specification language for contracts named Symboleo. The ontology of Symboleo is founded on the legal concepts of obligation (a kind of duty) and power (a kind of right) complemented with the concepts of event and situation that are suitable for conceptualizing monitoring tasks. The formal semantics of legal concepts is defined in terms of state machines that describe the lifetimes of contracts, obligations, and powers, as well as axioms that describe precisely state transitions. The language supports execution-time operations that enable subcontracting assignment of rights and substitution of performance to a third party during the execution of a contract. Symboleo has been applied to the formalization of contracts from three different domains as a preliminary evaluation of its expressiveness. Formal specifications can be algorithmically analyzed to ensure that they satisfy desired properties. Towards this end, the thesis presents two implemented analysis tools. One is a conformance checking tool (SymboleoPC) that ensures that a specification is consistent with the expectations of contracting parties. Expectations are defined for this tool in terms of scenarios (sequences of events) and the expected final outcome (i.e., successful/unsuccessful execution). The other tool (SymboleoPC), which builds on top of an existing model checker (nuXmv), can prove/disprove desired properties of a contract, expressed in temporal logic. These tools have been used for assessing different business contracts. SymboleoPC is also assessed in terms of performance and scalability, with positive results. Symboleo, together with its associated tools, is envisioned as an enabler for the formal verification of contracts to address requirements-level issues, at design time.

Patterns are a source of knowledge when architecting software systems. They provide abstract and time-tested solutions that show how a system should be structured to achieve needed qualities. However, when developing software there is a chance that small mistakes are introduced in the source code. Over time, these mistakes can accumulate and break the structure of the pattern and its qualities are lost. There are methods that can help find such errors, but none of these provide a pattern abstraction. In this work, we describe a method that raises the level of abstraction from checking individual dependencies to checking key dependencies in the pattern. We implement our method, apply it to check the Model-View-Controller pattern. We show that the method can find architectural problems in real source code and examine how removal of detected erosions affects the source code. We conducted an experiment in a software project setting to determine if using the method affects the number of architectural problems. Some project teams were randomly assigned to use a software service that automated our method. It checked how well their implementation conformed to Model-View-Controller every time they updated the source code. The experiment showed that developers that used the tool had significantly fewer detected architectural problems during the course of the project. Our method makes conformance checking easier to use. This might help increase the adoption of conformance checking in industry.

Anomaly detection in computer systems operating within complex environments,such as cyber-physical systems (CPS), has become increasingly popularduring these last years due to useful insights this process can provide aboutcomputer systems’ health conditions against known reference nominal states.As performance anomalies lead degraded service delivery, and, eventually,system-wide failures, promptly detecting such anomalies may trigger timelyrecovery responses. In this thesis, Process Mining, a discipline aiming at connectingdata science with process science, is broadly explored and employedfor detecting performance anomalies in complex computer systems, proposinga methodology for connecting event data to high-level process models forvalidating functional and non-functional requirements, evaluating system performances,and detecting anomalies. The proposed methodology is appliedto the industry-relevant European Rail Traffic Management System/EuropeanTrain Control System (ERTMS/ETCS) case-study. Experimental results sampledfrom an ERTMS/ETCS system Demonstrator implementing one of thescenarios the standard prescribe have shown Process Mining allows characterizingnominal system performances and detect deviations from such nominalconditions, opening the opportunity to apply recovery routines for steeringsystem performances to acceptable levels.

In complex information systems, it is often crucial to evaluate whether a sequence of activities obtained from a system log complies with behavioural rules. This process of evaluation is called conformance checking, and the most classical approach to specifying the behavioural rules is in the form of flow chartlike process diagrams, e.g., in the Business Process Model and Notation (BPMN) language. Traditionally, control flow constraints are extracted using Petri net replay-based approaches. Though, with the use of industrial process query languages such as Signavio Analytics Language (SIGNAL) that allows for temporal row matching, the possibility of performing conformance checking using temporal constraints opens up. To this end, this thesis presents a parser for extracting control-flow objects from BPMN-based business process models and a compiler for generating both linear temporal logic-like rules as well as SIGNAL queries. The parser succeeds at parsing all industry models and most academic models; the exceptions in the latter case can presumably be traced back to edge cases and unidiomatic modelling. The constraints generated by the compiler are in some, but not in all cases, identical to constraints extracted via Petri net replay as an intermediate step, indicating some differences in the formal interpretation of BPMN control flow. In conclusion, the implementation and evaluation of the parser and compiler indicate that it is feasible to move directly from business user-oriented process models to declarative, query language-based constraints, cutting out the Petri net-replay middleman and hence facilitating elegant and more efficient process data querying.

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-09-02T14:02:19Z No. of bitstreams: 1 SEBASTIÃO ESTEFÂNIO PINTO RABELO JÚNIOR - DISSERTAÇÃO PPGCC 2011..pdf: 13091249 bytes, checksum: 1cb0178385eb3bd7c5eb2d8c16dd72ac (MD5) / Made available in DSpace on 2018-09-02T14:02:19Z (GMT). No. of bitstreams: 1 SEBASTIÃO ESTEFÂNIO PINTO RABELO JÚNIOR - DISSERTAÇÃO PPGCC 2011..pdf: 13091249 bytes, checksum: 1cb0178385eb3bd7c5eb2d8c16dd72ac (MD5) Previous issue date: 2012-11-11 / Capes / Atualmente, quando se fala em UML, temos os diagramas de sequência como o mais popular entre os diagramas usados para descrever aspectos comportamentais de um software. Por outro lado, temos Java como uma das linguagens orientadas a objetos mais usada no mundo. Entretanto, não encontramos em nossas pesquisas um meio sistêmico para a verificação automática de conformidade entre modelos comportamentais e o código desenvolvido para atender esse modelo. Nesta dissertação, nós desenvolvemos uma abordagem capaz de verificar- esse tipo de conformidade. O uso dessa abordagem permitirá ajudai- desenvolvedores, analistas, e gerentes de projeto a manter a documentação do software atualizada, além de possibilitar a existência de um novo ponto de vista a respeito de defeitos na implementação de um sistema. Para dar suporte a essa verificação de conformidade nós desenvolvemos uma ferramenta baseada em Model Driven Architecture (MDA) capaz de gerar os testes de conformidade aqui apresentados. Além disso, esta dissertação traz uma avaliação da abordagem desenvolvida, a qual apresenta os principais resultados obtidos. / Currently, sequence diagrams are the most popular UML diagrams used to describe behavioral aspects of software systems. On the other hand, Java as one of the most popular object-oriented language used in lhe world. Despite that. there is no systematic approach to support verification between the behavioral design and the implemented source code. In this work, we propose an approach to verify this conformity. The use of this approach vvill help developers, architects, and engineers to maintain the software documentation updated. Its usage allows that the development team and managers to detect behavioral design implementation defects. We also present the tool support built for our approach using Model Driven Architecture (MDA) and a preliminary evaluation about this work.

Submitted by Alison Vanceto (alison-vanceto@hotmail.com) on 2017-01-06T12:32:32Z No. of bitstreams: 1 DissFBC.pdf: 2063843 bytes, checksum: 152295a2a8dcd2c521f4aad29a6fba78 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2017-01-16T12:01:27Z (GMT) No. of bitstreams: 1 DissFBC.pdf: 2063843 bytes, checksum: 152295a2a8dcd2c521f4aad29a6fba78 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2017-01-16T12:01:35Z (GMT) No. of bitstreams: 1 DissFBC.pdf: 2063843 bytes, checksum: 152295a2a8dcd2c521f4aad29a6fba78 (MD5) / Made available in DSpace on 2017-01-16T12:01:44Z (GMT). No. of bitstreams: 1 DissFBC.pdf: 2063843 bytes, checksum: 152295a2a8dcd2c521f4aad29a6fba78 (MD5) Previous issue date: 2016-03-03 / Não recebi financiamento / Architecture-Driven Modernization (ADM) is a model-based initiative for standardizing reengineering processes. Its most important meta-model is KDM (Knowledge Discovery Metamodel), which is a platform and language-independent ISO standard. A important step in an Architecture-Driven Modernization is the Architectural Conformance Checking (ACC), whose goal is to identify the violations between the Planned (PA) and Current Architectures (CA) of a system. Although there are ACC approaches that act on source-code or proprietary models, there is none for hystems represented as KDM. This absence hinders the dissemination of ADM and increases the interest for research that investigates the suitability of KDM in this context. Therefore, in this paper, we present ArchKDM, a KDMbased ACC approach that relies exclusively on the KDM meta-model for representing i) the legacy system under analysis; ii) the PA; iii) the CA; and iv) the violations between them. ArchKDM is composed of three tool-supported steps: 1) Specifying the Planned Architecture; 2) Extracting the Current Architecture; and 3) Performing the Checking. Our goal is to investigate the suitability of KDM as the main representation in all ACC steps as well as to deliver an ACC approach in the ADM context. We evaluated steps 2 and 3 of the approach using two real-world systems and the results showed no false positives and negatives. / Modernização Dirigida por Modelos (ADM) é uma iniciativa para a padronização dos processos de reengenharia. Dentre os metamodelos criados pela ADM, o mais importante é chamado de KDM (Metamodelo de Descoberta de Conhecimento), que é independente de plataforma e linguagem, além de ser padrão ISO. Uma importante etapa em uma Modernização Dirigida por Modelos é a Checagem de Conformidade Arquitetural (ACC), cujo objetivo é identificar violações entre as representações das arquiteturas planejada e atual de um sistema. Embora existam abordagens para ACC que atuam sobre código-fonte e modelos proprietários, não foram encontrados indícios desse tipo de abordagem para sistemas representados em KDM. Essa ausência de pesquisas na área dificulta a disseminação da ADM e aumenta o interesse em investigar a adequabilidade do KDM nesse contexto. Portanto, neste trabalho é apresentado o ArchKDM, uma abordagem para ACC baseado em KDM que depende exclusivamente do metamodelo KDM para representação i) do sistema legado a ser analisado; ii) da arquitetura planejada; iii) da arquitetura atual; e iv) das violações encontradas entre eles. ArchKDM é composta por três etapas: 1) Especificação da Arquitetura Planejada; 2) Extração da Arquitetura Atual; e 3) Checagem de Conformidade Arquitetural. O objetivo deste trabalho é investigar a adequabilidade do KDM como principal representação em todas as etapas da ACC, bem como fornecer uma abordagem para ACC no contexto da ADM. A abordagem foi avaliada utilizando dois sistemas reais e os resultados mostraram que não foram encontrados falsos positivos e negativos.

Detecting anomalies in computer-based systems, including Cyber-Physical Systems (CPS), has attracted a large interest recently. Behavioral anomalies represent deviations from what is regarded as the nominal expected behavior of the system. Both Process science and Data science can yield satisfactory results in detecting behavioral anomalies. Within Process Mining, Conformance Checking addresses data retrieval and the connection of data to behavioral models with the aim to detect behavioral anomalies. Nowadays, computer-based systems are increasingly complex and require appropriate validation, monitoring, and maintenance techniques. Within complex computer-based systems, the European Rail Traffic Management System/European Train Control System (ERTMS/ETCS) represents the specification of a standard Railway System integrating heterogeneous hardware and software components, with the aim of providing international interoperability with trains seemingly interacting within standardized infrastructures. Compliance with the standard as well as expected behavior is essential, considering the criticality of the system in terms of performance, availability, and safety. To that aim, a Process Mining Conformance Checking process can be employed to validate the requirements through run-time model-checking techniques against design-time process models. A Process Mining Conformance Checking methodology has been developed and applied with the goal of validating the behavior exposed by an ERTMS/ETCS system during the execution of specific scenarios. The methodology has been tested and demonstrated correct classification of valid behaviors exposed by the ERTMS/ETCS system prototype. Results also showed that the Fitness metric developed in the methodology allows the detection of latent errors in the system before they can generate any failures.