The Validation of Computer-based Models in Engineering: Some Lessons from Computing Science

Questions of the quality of computer-based models and the formal processes of model testing, involving internal verification and external validation, are usually given only passing attention in engineering reports and in technical publications. However, such models frequently provide a basis for analysis methods, design calculations or real-time decision-making in complex engineering systems. This paper reviews techniques used for external validation of computer-based models and contrasts the somewhat casual approach which is usually adopted in this field with the more formal approaches to software testing and documentation recommended for large software projects. Both activities require intimate knowledge of the intended application, a systematic approach and considerable expertise and ingenuity in the design of tests. It is concluded that engineering degree courses dealing with modelling techniques and computer simulation should put more emphasis on model limitations, testing and validation

Integrating formal methods into medical software development : the ASM approach

Medical devices are safety-critical systems since their malfunctions can seriously compromise human safety. Correct operation of a medical device depends upon the controlling software, whose development should adhere to certification standards. However, these standards provide general descriptions of common software engineering activities without any indication regarding particular methods and techniques to assure safety and reliability. This paper discusses how to integrate the use of a formal approach into the current normative for the medical software development. The rigorous process is based on the Abstract State Machine (ASM) formal method, its refinement principle, and model analysis approaches the method supports. The hemodialysis machine case study is used to show how the ASM-based design process covers most of the engineering activities required by the related standards, and provides rigorous approaches for medical software validation and verification

Review of Requirement Engineering Approaches for Software Product Lines

The Software Product Lines (SPL) paradigm is one of the most recent topics of interest for the software engineering community. On the one hand, the Software Product Lines is based on a reuse strategy with the aim to reduce the global time-to-market of the software product, to improve the software product quality, and to reduce the cost. On the other hand, traditional Requirement Engineering approaches could not be appropriated to deal with the new challenges that arises the SPL adoption. In the last years, several approaches have been proposed to cover this limitation. This technical report presents an analysis of specific approaches used in the development of SPL to provide solutions to model variability and to deal with the requirements engineering activities. The obtained results show that most of the research in this context is focused on the Domain Engineering, covering mainly the Feature Modeling and the Scenario Modeling. Among the studied approaches, only one of them supported the delta identification; this fact implies that new mechanisms to incorporate new deltas in the Domain specification are needed. Regarding the SPL adoption strategy, most of the approaches support a proactive strategy. However, this strategy is the most expensive and risk-prone. Finally, most of the approaches were based on modeling requirements with feature models giving less support to other important activities in the requirements engineering process such as elicitation, validation, or verification of requirements. The results of this study provide a wide view of the current state of research in requirements engineering for SPL and also highlight possible research gaps that may be of interest for researchers and practitioners.Blanes Domínguez, D.; Insfrán Pelozo, CE. (2011). Review of Requirement Engineering Approaches for Software Product Lines. http://hdl.handle.net/10251/1023

Verification and validation in systems engineering : application to UML 2.0 activity and class diagrams

The increasing complexity of industrial systems requires more efforts to be invested in the process of system verification and validation. The quality of such systems depends on the different types of techniques that are used to verify and ensure their correct functionality. The cost of maintaining systems in the latter phases of development is usually very high and may lead in most of the cases to inefficient solutions. Therefore, checking the correctness and validity of systems early in the design phase is greatly desirable. Different verification and validation techniques such as those involving testing and simulation are helpful and useful but may lack in many cases the desired level of rigor and completeness. Moreover, these conventional techniques are generally costly, laborious and time consuming. Conversely, using formal techniques, such as model-checking and program analysis along with design metrics complementary to the conventional verification techniques provides an elevated level of confidence since they are based on theoretical foundations. Systems Engineering is an interdisciplinary approach that aims to enable the successful realization and deployment of complex systems. Many modeling languages emerged in the systems engineering arena in order to provide the means for capturing and modeling of system's specifications and requirements. The most prominent languages are Unified Modeling Language (UML) 2.0 and Systems Modeling Languages (SysML). Formal verification and software engineering techniques can be applied in order to assess the correctness of different diagrams belonging to the aforementioned modeling languages. This research work presents a unified paradigm for the verification and validation of software and systems engineering design models expressed in UML 2.0 or SysML. The proposed paradigm relies on an established synergy between three salient approaches, which are model-checking, program analysis, and software engineering technique