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Developing complex engineering systems requires the consolidation of models from a variety of domains such as economics, mechanics and software engineering. These models are typically created using differing formalisms and by stakeholders that have varying views on the same problem statement. The challenging question is: what is needed to make sure that all of these different models remain consistent during the design process? A review of the related literature reveals that this is still an open challenge and has not yet been investigated at a fundamental level within the context of Model-Based Systems Engineering (MBSE). Therefore, this paper specifically focuses on examining the fundamentals of consistency management. We show that some inconsistencies cannot be detected and come to the conclusion that it is impossible to say whether or not a system is fully consistent. In this paper, we first introduce a mathematical foundation to define consistency in a formal manner. A decision-based approach to design is then studied and applied to the development of a real-world example. The research reveals several distinct types of inconsistencies that can occur during the design and development of a system. We show that these inconsistencies can be further classified into two groups: internal and external consistency. From these insights, the ontology of inconsistencies is constructed. Finally, requirements for possible tool support and methods to identify and manage specific types of consistency issues are proposed.

Embedded systems, with their tight technology integration, and multiple requirements and stakeholders, are characterized by tightly interrelated processes, information and tools. Embedded systems will as a consequence be described by multiple, heterogeneous and interrelated descriptions such as for example requirements documents, design and analysis models, software and hardware descriptions. We refer to a system designed this way as a multi-view (MV) system.The main contribution of this paper is a characterization of model-based approaches to MV systems. The characterization takes three main perspectives for the relations between viewpoints: semantic relations (content), relations over time (process), and manipulation of views (operations). We complement these perspectives by investigating MV system challenges and by a survey of related approaches. The characterization aims to provide a basis for a better understanding, design and implementation of MV systems, and thereby to overcome the current fragmented points of view on integrated multi-view modeling (MVM).

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Mechatronic design is traditionally supported through domain-specific design activities throughout the product development process. The partitioning into domain-specific problems leads to a situation where product properties influence each other, hence giving rise to dependencies. These dependencies play a key role in prediction of properties and as a result, in the decision making process. The important question is: how to manage the dependencies for an efficient and effective decision making? The aim of this paper is threefold. Firstly, we investigate the nature of dependencies and study how to model them. The paper proposes appropriate language constructs taking into account synthesis and analysis nature of properties and dependencies. The concepts related to the dependency modeling are then illustrated through a simple robot design example, where the creation and importance of a dependency model are explained. Secondly, we study practical approaches for consistency management and model management in the presence of dependencies. Six levels-ofdetail in modeling dependencies are presented; emphasizing that modeling at higher level-of-detail ensures that more inconsistencies are avoided. Available languages such as OMG SysML™ are evaluated for a possible creation of the dependency models leading towards executable dependency networks. However, at present, SysML does not provide sufficiently rich language constructs to model dependencies. Thirdly, we compare our dependency modeling approach to the other state-of-the-art approaches such as dependency modeling with a Design Structure Matrix, and highlight the benefits of the language constructs proposed in this paper. We aim to convince the reader that there is a substantial value in modeling dependencies explicitly, especially to avoid inconsistencies, which is not the current state of the practice. However, an overall value from dependency modeling can only be obtained if the cost of creating the dependency model is reasonable. Issues such as human interaction/effort and model management through PLM are discussed. INTRODUCTIONMechatronic design is a multi-disciplinary activity performed by multi-disciplinary design teams. In managing the design of such complex products, a model-based approach promises better complexity management, improved design quality, better knowledge reuse and improved communication [1]. These advantages are however also accompanied by challenges such as model management, interoperability, and consistency management. The ultimate goal in employing a model-based approach over a document-based approach is to make better decisions as early as possible (effectiveness) while utilizing fewer resources (efficiency).Using formal models enables use of computational power in predicting the outcomes. As complexity increases, the information which is typically part of a design specification becomes large, and computers can handle such large specifications much better than humans do through documents. Typically a model repository enables employm...

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