Electronic Communications of the EASST (European Association of Software Science and Technology)
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Using an OCL Impact Analysis Algorithm for View-Based Textual Modelling
Get PDFThe Object Constraint Language (OCL) has become a vital part of many frameworks, tools and languages within model-driven engineering. One such application of OCL is the use for describing rules in concrete syntax definitions. Within the textual modeling framework FURCAS, OCL is extensively used for the definition of lookup and attribution rules. Based on these rules the model which is described by such a textual representation is created and updated accordingly. Changes on models over which such an expression is specified require the expression to be re-evaluated to keep the constructed model up-to-date. However, the effort for re-evaluating OCL expressions over a set of model elements grows with the number of elements, the complexity of the expressions, and the number of model changes. Thus, having large models and/or complex expressions places considerable performance costs on OCL evaluation. Techniques to reduce this effort have been presented in previous work but do not cover the full range of OCL expressions, in particular calls to operations defined in OCL, including recursive operations. In this paper, we present an approach that is applicable to the full range of OCL expressions. We validated our approach based on a large set of models and complex expressions to evaluate the performance impact of our newly introduced techniques
Towards Transformation Rule Composition
Get PDFMany model transformation problems require different intermediate transformation steps. For example, platform-specific models (PSM) are often generated from platform-independent models (PIM) by chains of model transformations. This requires the presence of several intermediate meta-models between those of the PIM and the PSM. Thus, most of the effort is needed to define a transformation mechanism for each intermediate step. The solution proposed in this paper is to investigate whether it is possible to generate a single transformation from a chain of transformations, solely involving the initial PIM and final PSM meta-models. The presented work focuses on the composition of transformations at the rule level. We apply the automatic procedure for composing rules in the context of the evolution of the Enterprise Java Beans (EJB) language, transforming UML models into EJB 2.0 models and then to EJB 3.0 models
Visual Specification Patterns
Get PDFVisual modelling notations such as constraint diagrams can be used for the behavioural specifications of software components. This includes specifying invariants on classes or types and preconditions and postconditions of operations. However, one current problem in specifying components comes from the fact that editing constraints manually is time consuming and error prone and so we may adopt a pattern-based approach to alleviate this problem. One way to simplify the
definition of constraints is to identify and capture those recurring constraints in the form of visual specification patterns. Such patterns would facilitate the automatic generation of diagrammatic constraints. This paper identifies some specification
patterns that frequently occur when specifying software components and provides a diagrammatic representation of these patterns. This will form the basis of a library of specification patterns that could be used in the context of tools. We also show how such patterns can be combined in order to specify more complex constraints
Evaluation Strategies for Datalog-based Points-To Analysis
Get PDFDuring the last decade, several hard problems have been described and solved in Datalog in a sound way (points-to analyses, data web management, security, privacy, and trust). In this work, we describe novel evaluation strategies for this language within the context of program analyses. We first decompose any Datalog program into a program where rules have at most two atoms in their body. Then, we show that a specialized bottom-up evaluation algorithm with time and memory guarantees can be described as the on-the-fly resolution of a Boolean Equation System (Bes). The resolution computes all ground atoms in an efficient way thanks to a compact data structure with constant time access that has so far not been used in the Datalog or the Bes literature. A prototype has been developed and tested on a number of real Java projects in the context of Andersen’s points-to analysis. Experimental results show that our prototype is better than state-of-the-art solvers in terms of resolution time and memory consumption
Incremental update of constraint-compliant policy rules
Get PDFOrganizations typically define policies to describe (positive or negative) requirements about strategic objectives. Examples are policies relative to the security of information systems in general or to the control of access to an organization’s
resources. Often, the form used to specify policies is in terms of general constraints (what and why) to be enforced via the use of rules (how and when). The consistency of the rule system (transforming valid states into valid states) can be compromised and rules can violate some constraints when constraints are updated due to changing requirements. Here, we explore a number of issues related to constraint update, in particular proposing a systematic way to update rules as a consequence of modifications of constraints, by identifying which components of the rule have to be updated.
Moreover, we show the construction of sets of rules, directly derived from a positive constraint, to guarantee constraint preservation and constraint enforcement
Capturing the distinction between task and device errors in a formal model of user behaviour
Get PDFIn any complex interactive human-computer system, people are likely to make errors during its operation. In this paper, we describe a validation study of an existing generic model of user behaviour. The study is based on the data and conclusions from an independent prior experiment. We show that the current model does successfully capture the key concepts investigated in the experiment, particularly relating to results to do with the distinction between task and device-specific errors. However, we also highlight some apparent weaknesses in the current model with respect to initialisation errors, based on comparison with previously unpublished (and more detailed) data from the experiment. The differences between data and observed model behaviour suggest the need for new empirical research to determine what additional factors are at work. We also discuss the potential use of formal models of user behaviour in both informing, and generating further hypotheses about the causes of human error
Context awareness: Challenges and opportunities in modern smartphone use
Get PDFCommonly, improvement to smart-phone technology focuses at advancing the connectivity of human users. This results to better and richer information access but, undeniably, it also increases the accessibility of the users themselves, something that could arguably have negative side-effects. This position paper discusses the potential of context awareness in modern smart-phones by presenting the challenges and opportunities in modern smartphone use. In particular, we examine the implications of the advanced network capabilities—and accompanying services—of modern smart-phones and list what we argue to be their main drawbacks. We then present our position which summarizes what we expect the role of context-awareness to be in modern smart-phone applications
Enforcement of Patterns by Constraint-Aware Model Transformations
Get PDFPatterns are descriptions and solutions for recurring problems in software design and implementation. In this paper, some ideas towards a formal approach to the specification of patterns in model-driven engineering (MDE) is presented. The approach is based on the Diagram Predicate Framework which provides a formal approach to (meta)modelling, model transformation and model management in MDE. In particular, patterns are defined as diagrammatic specifications and constraint-aware model transformations are adapted to enforce patterns. Moreover, running examples are used to illustrate the facade design pattern in structural models
Supporting Mobile Application Development with Model-Driven Emulation
Get PDFIn this paper we outline our proposed approach for supporting mobile application development by using models as inputs to an emulator. We describe a new user interface to a parser tool previously developed, which enables developers to make design decisions about the user interface of the mobile application whilst ensuring that the resulting application adheres to the models. This paper describes work currently in progress
The Role of User Guidance in the Industrial Adoption of MDE Approach
Get PDFModel-Driven Engineering (MDE) has emerged as an actively researched and established approach for next generation control application development. Technology transfer to the industry is a topical research problem. Since most professional factory process control engineers do not have computer science backgrounds, there is an urgent need for studies of the role of user guidance in the professional learning, and thus, of industrial adoption of MDE approaches. In this study professionals were invited to a hands-on assessment of the AUKOTON MDE approach for factory process control engineering. Qualitative empirical material was collected and analyzed to identify the role of user guidance in the context of other factors impacting industrial adoption. Challenges in adoption that could be solved by user guidance were identified with the theory of organizational knowledge creation (SECI) model