Carol C. Burt

A quality‐of‐service‐based framework for creating distributed heterogeneous software components

Component‐based software development offers a promising solution for taming the complexity found in todays distributed applications. Todays and future distributed software systems will certainly require combining heterogeneous software components that are geographically dispersed. For the successful deployment of such a software system, it is necessary that its realization, based on assembling heterogeneous components, not only meets the functional requirements, but also satisfies the non‐functional criteria such as the desired quality of service (QoS). In this paper, a framework based on the notions of a meta‐component model, a generative domain model and QoS parameters is described. A formal specification based on two‐level grammar is used to represent these notions in a tightly integrated way so that QoS becomes a part of the generative domain model. A simple case study is described in the context of this framework. Copyright

Model driven security: unification of authorization models for fine-grain access control

The research vision of the Unified Component Meta Model Framework (Uniframe) is to develop infrastructure for components that enables a plug and play component environment where the security contracts are a part of the component description and the security aware middleware is generated by the component integration toolkits. That is, the component providers will define security contracts in addition to the functional contracts. These security contracts will be used to analyze the ability of a service to meet the security constraints when used in a composition of components. A difficulty in progressing the security related aspects of this infrastructure is the lack of a unified access control model that can be leveraged to identify protected resources and access control points at the model level. Existing component technologies utilize various mechanisms for specifying security constraints. This paper will explore issues related to expressing access control requirements of components and the resources they manage. It proposes a platform independent model (PIM) for the access control that can be leveraged to parameterize domain models. It also outlines the analysis necessary to progress a standard transformation from this PIM to three existing platform specific models (PSMs).

An architecture for the UniFrame resource discovery service

Frequently, the software development for large-scale distributed systems requires combining components that adhere to different object models. One solution for the integration of distributed and heterogeneous software components is the UniFrame approach. It provides a comprehensive framework unifying existing and emerging distributed component models under a conmion meta-model that enables the discovery, interoperability, and collaboration of components via generative software techniques. This paper presents the architecture for the resource discovery aspect of this framework, called the UniFrame Resource Discovery Service (URDS). The proposed architecture addresses the following issues: a) dynamic discovery of heterogeneous components, and b) selection of components meeting the necessary requirements, including desired levels of QoS (Quality of Service). This paper also compares the URDS architecture with other Resource Discovery Protocols, outlining the gaps that URDS is trying to bridge.

Quality of service issues related to transforming platform independent models to platform specific models

The UniFrame research project is proposing a Unified Component Meta Model Framework (UniFrame) that includes quality of service (QoS) contracts. Today it is the role of the software architect, based on experience, to design platform specific solutions that will meet QoS requirements. As we refine algorithms for model transformations, we must identify these QoS-aware design patterns and utilize them during model transformations. Our research includes supporting and participating in the exploration of generative techniques as they relate to QoS requirements (both static and dynamic) and the standardization of QoS-aware transformations. This paper explores how QoS requirements can impact decisions related to model transformation (using UML for Platform Independent Modeling and ISO IDL for the Platform Specific Model). It explores a series of QoS related design issues that must be considered as platform independent models are refined for specific component platforms.

Automated glue/wrapper code generation in integration of distributed and heterogeneous software components

UniFrame is a framework to help organizations to build interoperable distributed computing systems. Using UniFrame, a new system is built by assembling predeveloped heterogeneous and distributed software components. UniFrame solves the heterogeneity problem by explicitly modeling the domain knowledge of various technology domains (component model domains, programming language domains, operating system platform domains, etc.), from which the interoperation generative domain model (IGDM) straddling the technology domains can be constructed. The glue/wrapper code that realizes the interoperation among the distributed and heterogeneous software components can be generated from the IGDM. An informal implementation in Java of glue/wrapper code generator is given, followed by a discussion on a formalization of IGDM. The formalism comes from the fact that if the family of glue/wrapper code can be modeled formally, an instance glue/wrapper code can be generated automatically. In this formalization, the IGDM is formally modeled as a language definition using a grammar; the code that realizes the interoperation is a valid sentence derivable from the grammar, and will be generated automatically from the IGDM during the assembly time.

A Component Assembly Approach Based On Aspect-Oriented Generative Domain Modeling

We present an approach towards automatic component assembly based on aspect-oriented generative domain modeling. It involves the lifecycle covering the component specification generation, and subsequent assembly of implementation components to produce the final software system. Aspect-oriented techniques are applied to capture the crosscutting concerns that emerge during the assembly process. Subsequently, those concerns are woven to generate glue/wrapper code for assembling heterogeneous components to construct a single integrated system.

A meta-modeling approach to Web services

Web services (WS) technology is becoming pervasive in the development of distributed systems and is an appealing vehicle for service presentation and horizontal integration. On the other hand, model integrated computing (MIC) offers a means of system integration in the vertical direction by using domain-specific modeling, and then synthesizing the software system from the high-level model using a model-specific generator. This paper presents a meta-modeling approach to WS to explore the application of MIC in WS development and its contribution.

Component Specification and Wrapper/Glue Code Generation with Two-Level Grammar Using Domain Specific Knowledge

UniFrame is a framework for seamlessly assembling heterogeneous distributed components. Its based on the Unified Meta-component Model (UMM) for describing components. Systems constructed by component composition should meet both functional and non-functional requirements such as the Quality of Service (QoS). We propose a Component Description Language (CDL) to specify the UMM components based on domain specific knowledge in the context of UniFrame using Two-Level Grammar (TLG). CDL is also used for wrapper/glue code generation. A simple case study is illustrated to show how CDL may be applied.

Composition and decomposition of quality of service parameters in distributed component-based systems

It is becoming increasingly acceptable that component-based development is an effective, efficient and promising approach to develop distributed systems. With components as the building blocks, it is expected that the quality of the end system can be predicted based on the qualities of components in the system. UniFrame is one such framework that facilitates seamless interoperation of heterogeneous distributed software components. As a part of UniFrame, a catalog of quality of service (QoS) parameters has been created to provide a standard method for quantifying the QoS of software components. In this paper, an approach for composition and decomposition of these QoS parameters is proposed. A case study from the financial domain is indicated to validate this model.

A translation approach to component specification

UniFrame is a framework for seamlessly assembling heterogeneous distributed components. It is based on the Unified Meta-component Model (UMM). UniFrame uses two-level grammar (TLG) for formally specifying components and translation into other component representations for component service export and assembly.