Zinovy Diskin

A comparative survey of scenario-based to state-based model synthesis approaches

Model Driven Development and Use Case Driven Development methodologies have inspired the proposal of a variety of software engineering approaches that synthesize state-based models from scenario-based models. However, little work has been done to comprehensively compare these different synthesis approaches. In this paper, we define a set of comparison criteria, and survey 21 different synthesis approaches presented in the literature based on the criteria. The differences and similarities are highlighted in the comparison results. We then discuss the challenges that current approaches may face and provide suggestions for future work for state-based model syntheses.

From state- to delta-based bidirectional model transformations: the symmetric case

A bidirectional transformation (BX) keeps a pair of interrelated models synchronized. Symmetric BXs are those for which neither model in the pair fully determines the other. We build two algebraic frameworks for symmetric BXs, with one correctly implementing the other, and both being delta-based generalizations of known state-based frameworks. We identify two new algebraic laws--weak undoability and weak invertibility, which capture important semantics of BX and are useful for both state- and delta-based settings. Our approach also provides a flexible tool architecture adaptable to different users needs.

Algebraic Models for Bidirectional Model Synchronization

The paper presents several algebraic models for semantics of bidirectional model synchronization and transformation. Different patterns of model synchronization are analyzed (including view updates and incremental synchronization), and this analysis motivates the formal definitions. Relationships between the formal models are precisely specified and discussed. A new formal model of updates is proposed.

Correctness of model synchronization based on triple graph grammars

Triple graph grammars (TGGs) have been used successfully to analyze correctness and completeness of bidirectional model transformations, but a corresponding formal approach to model synchronization has been missing. This paper closes this gap by providing a formal synchronization framework with bidirectional update propagation operations. They are generated from a TGG, which specifies the language of all consistently integrated source and target models. As a main result, we show that the generated synchronization framework is correct and complete, provided that forward and backward propagation operations are deterministic. Correctness essentially means that the propagation operations preserve consistency. Moreover, we analyze the conditions under which the operations are inverse to each other. All constructions and results are motivated and explained by a small running example using concrete visual syntax and abstract syntax notation based on typed attributed graphs.

Understanding and improving UML package merge

Package merge allows the content of one package to be combined with that of another package. Package merge is used extensively in the UML 2 specification to modularize the definition of the UML 2 meta model and to define the four compliance levels of UML 2. Package merge is a novel construct in UML and currently not well understood. This paper summarizes our work to understand and improve package merge. First, we identify ambiguous and missing rules in the package merge definition and suggest corrections. Then, we formalize package merge and analyze it with respect to some desirable properties. Our analyses employs Alloy, a first-order modelling language with tool support, and concepts from mathematical logic which allow us to develop a general taxonomy of package extension mechanisms. The analyses reveal the unexpected failure of important properties.

Clafer: unifying class and feature modeling

We present Clafer (class, feature, reference), a class modeling language with first-class support for feature modeling. We designed Clafer as a concise notation for meta-models, feature models, mixtures of meta- and feature models (such as components with options), and models that couple feature models and meta-models via constraints (such as mapping feature configurations to component configurations or model templates). Clafer allows arranging models into multiple specialization and extension layers via constraints and inheritance. We identify several key mechanisms allowing a meta-modeling language to express feature models concisely. Clafer unifies basic modeling constructs, such as class, association, and property, into a single construct, called clafer. We provide the language with a formal semantics built in a structurally explicit way. The resulting semantics explains the meaning of hierarchical models whereby properties can be arbitrarily nested in the presence of inheritance and feature modeling constructs. The semantics also enables building consistent automated reasoning support for the language: To date, we implemented three reasoners for Clafer based on Alloy, Z3 SMT, and Choco3 CSP solvers. We show that Clafer meets its design objectives using examples and by comparing to other languages.

Model synchronization: mappings, tiles, and categories

The paper presents a novel algebraic framework for specification and design of model synchronization tools. The basic premise is that synchronization procedures, and hence algebraic operations modeling them, are diagrammatic: they take a configuration (diagram) of models and mappings as their input and produce a diagram as the output. Many important synchronization scenarios are based on diagram operations of square shape. Composition of such operations amounts to their tiling, and complex synchronizers can thus be assembled by tiling together simple synchronization blocks. This gives rise to a visually suggestive yet precise notation for specifying synchronization procedures and reasoning about them.

A Diagrammatic Logic for Object-Oriented Visual Modeling

Formal generalized sketches is a graph-based specification format that borrows its main ideas from categorical and ordinary first-order logic, and adapts them to software engineering needs. In the engineering jargon, it is a modeling language design pattern that combines mathematical rigor and appealing graphical appearance. The paper presents a careful motivation and justification of the applicability of generalized sketches for formalizing practical modeling notations. We extend the sketch formalism by dependencies between predicate symbols and develop new semantic notions based on the Instances-as-typed-structures idea. We show that this new framework fits in the general patterns of the institution theory and is well amenable to algebraic manipulations.

Universal Arrow Foundations for Visual Modeling

The goal of the paper is to explicate some common formal logic underlying various notational systems used in visual modeling. The idea is to treat the notational diversity as the diversity of visualizations of the same basic specificational format. It is argued that the task can be well approached in the arrow-diagramlogic framework where specifications are directed graphs carrying a structure of diagram predicates and operations.

From state- to delta-based bidirectional model transformations

Existing bidirectional model transformation languages are mainly state-based: a transformation is considered composed from functions whose inputs and outputs only consist of original and updated models, but alignment relationships between the models are not specified. In the paper we identify and discuss three major problems caused by this under-specification. We then propose a novel formal framework based on a graphical language: models are nodes and updates are arrows, and show how the three problems can be fixed.