Mikhail Auguston

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

A framework for automatic debugging

This paper presents an application framework in which declarative specifications of debugging actions are translated into execution monitors that can automatically detect bugs. The approach is non-intrusive with respect to program source code and provides a high level of abstraction for debugging activities.

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.

Environment behavior models for automation of testing and assessment of system safety

Abstract This paper presents an approach to automatic scenario generation from environment behavior models for testing of real-time reactive systems. The model of behavior is defined as a set of events (event trace) with two basic relations: precedence and inclusion. The attributed event grammar (AEG) specifies possible event traces and provides a uniform approach for automatically generating and executing test cases. The environment model includes a description of hazardous states in which the system may arrive and makes it possible to gather statistics for system safety assessment. The approach is supported by a generator that creates test cases from the AEG models. We demonstrate the approach with a case study of a software prototype of the computer-assisted resuscitation algorithm for a safety-critical casualty intravenous fluid infusion pump.

Software architecture built from behavior models

This paper suggests an approach to formal software system architecture specification based on behavior models. The behavior of the system is defined as a set of events (event trace) with two basic relations: precedence and inclusion. The structure of event trace is specified using event grammars and other constraints organized into schemas. The schema framework is amenable to stepwise architecture refinement, reuse, composition, visualization, and application of automated tools for consistency checks. The concept of event attribute supports a continuous architecture refinement up to executable design and implementation models.

Using assertions in declarative and operational models for automated debugging

This article presents an improved method for semiautomatic bug localization, by extending our previous generalized algorithm debugging technique, (GADT) [Fritzson et al. 1991], which uses declarative assertions about program units such as procedures and operational assertions about program behavior. For example, functional properties are best expressed through declarative assertions about procedure units, whereas order-dependent properties, or sequencing constraints in general, are more easily expressed using operational semantics. A powerful assertion language, called FORMAN, has been developed to this end. Such assertions can be collected into assertion libraries, which can greatly increase the degree of automation in bug localization. The long-range goal of this work is a semiautomatic debugging and testing system, which can be used during large-scale program development of nontrivial programs. To our knowledge, the extended GADT (EGADT) presented here is the first method that uses powerful operational assertions integrated with algorithmic debugging. In addition to providing support for local-level bug localization within procedures (which is not handled well by basic algorithmic debugging), the operational assertions reduce the number of irrelevant questions to the programmer during bug localization, thus further improving bug localization. A prototype of the GADT, implemented in PASCAL, supports debugging in a subset of Pascal. An interpreter of FORMAN assertions has also been implemented in PASCAL. During bug localization, both declarative and operational assertions are evaluated on execution traces.

Environment behavior models for scenario generation and testing automation

This paper suggests an approach to automatic scenario generation from environment models for testing of real-time reactive systems. The behavior of the system is defined as a set of events (event trace) with two basic relations: precedence and inclusion. The attributed event grammar (AEG) specifies possible event traces and provides a uniform approach for automatically generating, executing, and analyzing test cases. The environment model includes a description of hazardous states in which the system may arrive and makes it possible to gather statistics for system safety assessment. The approach is supported by a generator that creates test cases from the AEG models. We demonstrate the approach with case studies of prototypes for the safety-critical computer-assisted resuscitation algorithm (CARA) software for a casualty intravenous fluid infusion pump and the Paderborn Shuttle System.

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.

Iterative constructs in the visual data flow language

We suggest a solution for iterative processing in data flow diagrams based on the notion of a conditional data flow switch, and a specialized iterative construct based on pattern matching for vectors and matrices. Both of these constructs can be seamlessly incorporated into V, a data-flow visual programming language. We demonstrate how these constructs may be used to reveal the spatial/temporal dualism of data streams.