@article {Simula.simula.1066,
	title = {Matching and Merging of Variant Feature Specifications},
	journal = {IEEE Transactions on Software Engineering},
	volume = {38},
	number = {6},
	year = {2012},
	pages = {1355-1375},
	publisher = {IEEE},
	abstract = {Model Management addresses the problem of managing an evolving collection of models, by capturing the relationships between models and providing well-defined operators to manipulate them. In this article, we describe two such operators for manipulating feature specifications described using hierarchical state machine models: Match, for finding correspondences between models, and Merge, for combining models with respect to known or hypothesized correspondences between them. Our Match operator is heuristic, making use of both static and behavioural properties of the models to improve the accuracy of matching. Our Merge operator preserves the hierarchical structure of the input models, and handles differences in behaviour through parameterization. This enables us to automatically construct merges that preserve the semantics of hierarchical state machines. We report on tool support for our Match and Merge operators, and illustrate and evaluate our work by applying these operators to a set of telecommunication features built by AT\&amp;T.},
	author = {Nejati, Shiva and Sabetzadeh, Mehrdad and Chechik, Marsha and Easterbrook, Steve and Zave, Pamela}
}
@inproceedings {Simula.approve.58,
	title = {Reasoning About Consistency in Model Merging},
	journal = {3rd Workshop on Living With Inconsistency in Software Development},
	year = {2010},
	publisher = {CEUR Workshop Proceedings},
	type = {Workshop},
	abstract = {Models undergo a variety of transformations throughout development. One of the key transformations is merge, used when developers need to combine a set of models with respect to the overlaps between them. A major question about model transformations in general, and merge in particular, is what consistency properties are preserved across the transformations and what consistency properties may need to be re-checked (and if necessary, re-established) over the result. In previous work, we developed a technique based on category-theoretic colimits for merging sets of inter-related models. The use of category theory leads to the preservation of the algebraic structure of the source models in the merge; however, this does not directly provide a characterization of the (in)consistency properties that carry over from the source models to the result, because consistency properties are predominantly expressed as logical formulas. Hence, an investigation of the connections between the {\textquoteleft}{\textquoteleft}algebraic{\textquoteright}{\textquoteright} and {\textquoteleft}{\textquoteleft}logical{\textquoteright}{\textquoteright} properties of model merging became necessary. In this paper, we undertake such an investigation and use techniques from finite model theory to show that the use of colimits indeed leads to the preservation of certain logical properties. Our results have implications beyond our merge framework in and are potentially useful for the broad range of techniques in the graph transformation and algebraic specification literature that use colimits as the basis for model manipulations.},
	isbn = {urn:nbn:de:0074-661-4},
	author = {Sabetzadeh, Mehrdad and Nejati, Shiva and Chechik, Marsha and Easterbrook, Steve},
	editor = {Egyed, A. and Lopez-Herrejon, R. and Nuseibeh, B. and Botterweck, G. and Chechik, M. and Hu, Z.}
}
@inproceedings {19096,
	title = {A Manifesto for Model Merging},
	journal = {1st International Workshop on Global Integrated Model Management (GaMMa{\textquoteright}06) at the 28th International Conference on Software Engineering},
	year = {2006},
	publisher = {IEEE},
	address = {unknown},
	abstract = {If a modeling task is distributed, it will frequently be neces- sary to merge models developed by di erent team members. Existing approaches to model merging make assumptions about the types of model to be merged, and the nature of the relationship between them. This makes it hard to compare approaches. In this paper, we present a manifesto for re- search on model merging. We propose a framework for com- paring di erent approaches to merging, by treating merge as an algebraic operator over models and model relationships. We specify the algebraic properties of an idealized merge operator, as well as related operators such as match, di , split, and slice. We then show how our framework can be used to compare existing approaches by applying it to two of our own research projects on model merging. We show how this analysis permits a detailed comparison of approaches, reveals the key features of each, and identi es weaknesses that require further research. Most importantly, the frame- work emphasizes the need to make explicit all assumptions about the relationships between models, and indeed to treat model relationships as rst class objects.},
	author = {Brunet, Greg and Chechik, Marcha and Easterbrook, Steve and Nejati, Shiva and Niu, Nan and Sabetzadeh, Mehrdad}
}
@article {Simula.simula.466,
	title = {View Merging in the Presence of Incompleteness and Inconsistency},
	journal = {Requirements Engineering},
	volume = {11},
	number = {3},
	year = {2006},
	pages = {174-193},
	abstract = {View merging, also called view integration, is a key problem in conceptual modeling. Large models are often constructed and accessed by manipulating individual views, but it is important to be able to consolidate a set of views to gain a unified perspective, to understand interactions between views, or to perform various types of analysis. View merging is complicated by incompleteness and inconsistency: Stakeholders often have varying degrees of confidence about their statements. Their views capture different but overlapping aspects of a problem, and may have discrepancies over the terminology being used, the concepts being modeled, or how these concepts should be structured. Once views are merged, it is important to be able to trace the elements of the merged view back to their sources and to the merge assumptions related to them. In this paper, we present a framework for merging incomplete and inconsistent graph-based views. We introduce a formalism, called annotated graphs, with a built-in annotation scheme for modeling incompleteness and inconsistency. We show how structure-preserving maps can be employed to express the relationships between disparate views modeled as annotated graphs, and provide a general algorithm for merging views with arbitrary interconnections. We provide a systematic way to generate and represent the traceability information required for tracing the merged view elements back to their sources, and to the merge assumptions giving rise to the elements.},
	author = {Sabetzadeh, Mehrdad and Easterbrook, Steve}
}
