Iman Poernomo

The meta-object facility typed

The Object Managment Groups Meta-Object Facility (MOF) [9] is a semiformal approach to writing models and metamodels (models of models). The MOF was developed to enable systematic model/metamodel interchange and integration. The approach is problematic, unless metamodels are correctly specified: an error in a metamodel specification will propagate throughout instantiating models and final model implementations. An important open question is how to develop provably correct metamodels. This paper outlines a solution to the question, in which the MOF meta-modelling approach is formalized within constructive type theory.

Efficient Multi-granularity Service Composition

Dynamic composition of services provides the ability to build complex distributed applications at run time by combining existing services, thus coping with a large variety of complex requirements that cannot be met by individual services alone. However, with the increasing amount of available services that differ in granularity (amount of functionality provided) and qualities, selecting the best combination of services becomes very complex. In response, this paper addresses the challenges of service selection, and makes a twofold contribution. First, a rich representation of compositional planning knowledge is provided, allowing the expression of multiple decompositions of tasks at arbitrary levels of granularity. Second, two distinct search space reduction techniques are introduced, the application of which, prior to performing service selection, results in significant improvement in selection performance in terms of execution time, which is demonstrated via experimental results.

Correct-by-construction model transformations from partially ordered specifications in Coq

This paper sketches an approach to the synthesis of provably correct model transformations within the Coq theorem prover, an implementation of Coquand and Huets Calculus of Inductive Constructions. It extends work done by Poernomo on proofs-as-model-transformations in the related formalism of Martin-Lof predicative Constructive Type Theory. We show how the impredicative theory of Coq, together with its treatment of coinductive types, lends itself to the synthesis of a wider range of model transformations than Poernomo had treated before. We illustrate the practical benefits and potential scalability of our approach by means of a case study taken from industry.

A model-oriented framework for runtime monitoring of nonfunctional properties

It is now recognized that nonfunctional properties are important to practical software development and maintenance. Many of these properties involve involving time and probabilities – for example, reliability and availability. One approach to ensuring conformance to nonfunctional requirements is the use of runtime monitoring. Currently, such monitoring is done in one of two ways: 1) monitoring through use of a generic tool or 2) by adding instrumentation code within system software and writing a tool to manage resulting datasets. The first approach is often not flexible while the second approach can lead to a higher development cost. In this paper, we present a flexible framework for runtime verification of timed and probabilistic nonfunctional properties of component-based architectures. We describe a Microsoft .NET-based implementation of our framework built upon the Windows Management Instrumentation (WMI) infrastructure and the Distributed Management Task Force’s Common Information Model standard. We use a language for contracts based on Probabilistic Computational Tree Logic (PCTL). We provide a formal semantics for this language based on possible application execution traces. The semantics is generic over the aspects of an application that are represented by states and transitions of traces. This enables us to use the language to define a wide range of nonfunctional properties.

A constructive approach to testing model transformations

This paper concerns a formal encoding of the Object Management Groups Complete Meta-Object Facility (CMOF) in order to provide a more trustworthy software development lifecycle for Model Driven Architecture (MDA). We show how a form of constructive logic can be used to provide a uniform semantics of metamodels, model transformation specifications, model transformations and black-box transformation tests. A models instantiation of a metamodel within the MOF is treated using the logics realizability relationship, a kind of type inhabitation relationship that is expressive enough to characterize constraint conformance between terms and types. These notions enable us to formalize the notion of a correct model instantiation of a metamodel with constraints. We then adapt previous work on snapshot generation to generate input models from source metamodel specification with the purpose of testing model transformations.

A type theoretic framework for formal metamodelling

The Object Managment Groups Meta-Object Facility (MOF) [19] is a semiformal approach to writing models and metamodels (models of models). It works according to a model/metamodel hierarchy, where software is specified by models, models are defined as instances of metamodels, which are, in turn, defined as instances of the MOF meta-metamodel. By writing models and metamodels in a common framework, the MOF meta-metamodel, it is easier to perform systematic model/metamodel interchange and integration. However, the approach is only useful if metamodels are correctly specified – a single error in a metamodel specification will result in the propagation of errors throughout instantiating models and final model implementations. An important open question is how to develop provably correct metamodels. This paper applies constructive type theory to formalize the MOF metamodelling approach. The benefit of the formalization is that correct typing corresponds to provably correct metamodels and models. Because the MOF is the central technology behind the Model Driven Architecture initiative [18], our work is intended to lay a formal foundation for making Model Driven Architecture more trustworthy.

QoS-aware model driven architecture through the UML and CIM

The specification of Quality of Service (QoS) constraints over software design requires measures that ensure such requirements are met by the delivered product. Achieving this goal is non-trivial, as it involves, at least, identifying how QoS constraint specifications should be checked at the runtime. In this paper we present an implementation of a Model Driven Architecture (MDA) based framework for the runtime monitoring of QoS properties. We incorporate the UML2 superstructure and the UML profile for Quality of Service to provide abstract descriptions of component-and-connector systems. We then define transformations that refine the UML2 models to conform with the Distributed Management Taskforce (DMTF) Common Information Model (CIM) (Distributed Management Task Force Inc. 2006), a schema standard for management and instrumentation of hardware and software. Finally, we provide a mapping the CIM metamodel to a .NET-based metamodel for implementation of the monitoring infrastructure utilising various .NET features including the Windows Management Instrumentation (WMI) interface.

QoS-Aware Model Driven Architecture through the UML and CIM

The specification of quality of service (QoS) constraints over software design requires measures that ensure such requirements are met by the delivered product. Achieving this goal is non-trivial, as it involves, at least, identifying how QoS constraint specifications should be checked at the runtime. In this paper we present an implementation of a model driven architecture (MDA) based framework for the runtime monitoring of QoS properties. We incorporate the UML2 superstructure and the UML profile for quality of service to provide abstract descriptions of component-and-connector systems. We then define transformations that refine the UML2 models to conform with the distributed management taskforce (DMTF) common information model (CIM) (2006), a schema standard for management and instrumentation of hardware and software. Finally, we provide a mapping the CIM metamodel to a .NET-based metamodel for implementation of the monitoring infrastructure utilising various .NET features including the Windows Management Instrumentation (WML) interface

Timed probabilistic constraints over the Distributed Management Taskforce common information model

It is now recognized that nonfunctional properties are important to practical software development and maintenance. Many of these properties involve time and probabilities - for example, reliability and availability. In this paper, we present a framework for runtime verification of timed and probabilistic nonfunctional properties of component-based architectures, built using the meta-object facility and the Distributed Management Task Forces common information model (CIM) standard. We describe a Microsoft .NET-based implementation of our framework. We use a language for contracts based on probabilistic computational tree logic (PCTL). We provide a formal semantics for this language based on possible application execution traces. The semantics is parametrized with respect to the choice of application states and state changes to be monitored. This enables us to use the language to define a wide range of nonfunctional properties. We explain how our framework associates constraints with systems that expose management information through the CIM, via a novel extension of the CIM metamodel.

Prototype Generation from Ontology Charts

Semantic analysis (SAM) is a business analysis method designed to capture system requirements. While these requirements may be represented as text, the method also advocates the use of ontology charts to formally denote the systems required roles, relationships and forms of communication. The method works as follows: initially the problem must be defined by domain experts and passed to the project analyst(s). The next step is the generation of candidate affordances. This step will generate a list of semantic units that may be included in the schema. The candidate grouping follows where some of the semantic units that will appear in the schema are placed in simple groups. Finally the groups will be integrated together into an ontology chart.