Simplification of UML/OCL schemas for efficient reasoning

Ensuring the correctness of a conceptual schema is an essential task in order to avoid the propagation of errors during software development. The kind of reasoning required to perform such task is known to be exponential for UML class diagrams alone and even harder when considering OCL constraints. Motivated by this issue, we propose an innovative method aimed at removing constraints and other UML elements of the schema to obtain a simplified one that preserve the same reasoning outcomes. In this way, we can reason about the correctness of the initial artifact by reasoning on a simplified version of it. Thus, the efficiency of the reasoning process is significantly improved. In addition, since our method is independent from the reasoning engine used, any reasoning method may benefit from it.Peer ReviewedPostprint (author's final draft

Towards code generation from design models

With the growing in size and complexity of modern computer systems, the need for improving the quality at all stages of software development has become a critical issue. The current software production has been largely depended on manual code development. Despite the slow development process, the errors introduced by the programmers contribute to a substantial portion of defects in the final software product. This paper explores the possibility of generating code and assertion constraints from formal design models and use them to verify the implementation. We translate Z formal models into their OCL counter-parts and Java assertions. With the help of existing tools, we demonstrate various checking at different levels to enhance correctness

Transformation As Search

In model-driven engineering, model transformations are con- sidered a key element to generate and maintain consistency between re- lated models. Rule-based approaches have become a mature technology and are widely used in different application domains. However, in var- ious scenarios, these solutions still suffer from a number of limitations that stem from their injective and deterministic nature. This article pro- poses an original approach, based on non-deterministic constraint-based search engines, to define and execute bidirectional model transforma- tions and synchronizations from single specifications. Since these solely rely on basic existing modeling concepts, it does not require the intro- duction of a dedicated language. We first describe and formally define this model operation, called transformation as search, then describe a proof-of-concept implementation and discuss experiments on a reference use case in software engineering

Computing repairs for constraint violations in UML/OCL conceptual schemas

Updating the contents of an information base may violate some of the constraints defined over the schema. The classical way to deal with this problem has been to reject the requested update when its application would lead to some constraint violation. We follow here an alternative approach aimed at automatically computing the repairs of an update, i.e., the minimum additional changes that, when applied together with the requested update, bring the information base to a new state where all constraints are satisfied. Our approach is independent of the language used to define the schema and the constraints, since it is based on a logic formalization of both, although we apply it to UML and OCL because they are widely used in the conceptual modeling community. Our method can be used for maintaining the consistency of an information base after the application of some update, and also for dealing with the problem of fixing up non-executable operations. The fragment of OCL that we use to define the constraints has the same expressiveness as relational algebra and we also identify a subset of it which provides some nice properties in the repair-computation process. Experiments are conducted to analyze the efficiency of our approach.Peer ReviewedPostprint (author's final draft

WARP : speeding up the software development process

Estágio realizado na Qimonda Portugal, S. ATese de mestrado integrado. Engenharia Informátca e Computação. Faculdade de Engenharia. Universidade do Porto. 200

Computing the Importance of Schema Elements Taking Into Account the Whole SCHEMA

Conceptual Schemas are one of the most important artifacts in the development cycle of information systems. To understand the conceptual schema is essential to get involved in the information system that is described within it. As the information system increases its size and complexity, the relative conceptual schema will grow in the same proportion making di cult to understand the main concepts of that schema/information system. The thesis comprises the investigation of the in uence of the whole schema in computing the relevance of schema elements. It will include research and implementation of algorithms for scoring elements in the literature, an study of the di erent results obtained once applied to a few example conceptual schemas, an extension of those algorithms including new components in the computation process like derivation rules, constraints and the behavioural subschema speci cation, and an in-depth comparison among the initial algorithms and the extended ones studying the results in order to choose those algorithms that give the most valuable output

Ensuring the semantic correctness of a BAUML artifact-centric BPM

Context: Using models to represent business processes provides several advantages, such as facilitating the communication between the stakeholders or being able to check the correctness of the processes before their implementation. In contrast to traditional process modeling approaches, the artifact-centric approach treats data as a key element of the process, also considering the tasks or activities that are performed in it. Objective: This paper presents a way to verify and validate the semantic correctness of an artifact-centric business process model defined using a combination of UML and OCL models - a BAUML model. Method: We achieve our goal by presenting several algorithms that encode the initial models into first-order logic, which then allows to use an existing satisfiability checking tool to determine their correctness. Results: An approach to verify and validate an artifact-centric BPM specified in BAUML, which uses a combination of UML and OCL models. To do this, we provide a method to translate all BAUML components into a set of logic formulas. The result of this translation ensures that the only changes allowed are those specified in the model, and that those changes are taking place according the order established by the model. Having obtained this logic representation, these models can be validated by any existing reasoning method able to deal with negation of derived predicates. Moreover, we show how to automatically generate the relevant tests to validate the models. We also show the feasibility of our approach by implementing a prototype tool and applying it to a running example. Conclusion: It is feasible to ensure the semantic correctness of an artifact-centric business process model in practice.Peer ReviewedPostprint (author's final draft

CSTL: A Conceptual Schema Testing Language

Like any software artifact, conceptual schemas of information systems can be tested. Testing conceptual schemas has some similarities with testing programs, but there are important differences. We present a list of six kinds of tests that can be applied to conceptual schemas. Some of them require schemas comprising both the structural and the behavioral parts, but we show that it is useful to test incomplete schema fragments, even if they consist of only a few entity and relationship types, integrity constraints and derivation rules. We present CSTL, a language for writing automated tests of executable schemas written in UML/OCL. CSTL follows the style of the modern xUnit testing frameworks. Tests written in CSTL can be executed as many times as needed. We describe an implementation of a test processor, which includes a test manager and a test interpreter that coordinates the execution of the tests. Finally, we apply CSTL to the conceptual schema of a real-world information system

Test Generation and Evaluation from High-Level Properties for Common Criteria Evaluations - The TASCCC Testing Tool

International audienceIn this paper, we present a model-based testing tool resulting from a research project, named TASCCC. This tool is a complete tool chain dedicated to property-based testing in UML/OCL, that integrates various technologies inside a dedicated Eclipse plug-in. The test properties are expressed in a dedicated language based on property patterns. These properties are then used for two purposes. First, they can be employed to evaluate the relevance of a test suite according to specific coverage criteria. Second, it is possible to generate test scenarios that will illustrate or exercise the property. These test scenarios are then unfolded and animated on the Smartesting's CertifyIt model animator, that is used to filter out infeasible sequences. This tool has been used in industrial partnership, aiming at providing an assistance for Common Criteria evaluations, especially by providing test generation reports used to show the link between the test cases and the Common Criteria artefacts