Krishnakumar Balasubramanian

Developing applications using model-driven design environments

Historically, software development methodologies have focused more on improving tools for system development than on developing tools that assist with system composition and integration. Component-based middleware like Enterprise Java-Beans (EJB), Microsoft .NET, and the CORBA Component Model (CCM) have helped improve software reusability through component abstraction. However, as developers have adopted these commercial off-the-shelf technologies, a wide gap has emerged between the availability and sophistication of standard software development tools like compilers and debuggers, and the tools that developers use to compose, analyze, and test a complete system or system of systems. As a result, developers continue to accomplish system integration using ad hoc methods without the support of automated tools. Model-driven development is an emerging paradigm that solves numerous problems associated with the composition and integration of large-scale systems while leveraging advances in software development technologies such as component-based middleware. MDD elevates software development to a higher level of abstraction than is possible with third-generation programming languages.

A platform-independent component modeling language for distributed real-time and embedded systems

This paper provides two contributions to the study of developing and applying domain-specific modeling languages (DSMLS) to distributed real-time and embedded (DRE) systems - particularly those systems using standards-based QoS-enabled component middleware. First, it describes the platform-independent component modeling language (PICML), which is a DSML that enables developers to define component interfaces, QoS parameters and software building rules, and also generates descriptor files that facilitate system deployment. Second, it applies PICML to an unmanned air vehicle (UAV) application portion of an emergency response system to show how PICML resolves key component-based DRE system development challenges. Our results show that the capabilities provided by PICML - combined with its design and deployment-time validation capabilities - eliminates many common errors associated with conventional techniques, thereby increasing the effectiveness of applying QoS-enabled component middleware technologies to the DRE system domain.

Model driven middleware: A new paradigm for developing distributed real-time and embedded systems

Distributed real-time and embedded (DRE) systems have become critical in domains such as avionics (e.g., flight mission computers), telecommunications (e.g., wireless phone services), tele-medicine (e.g., robotic surgery), and defense applications (e.g., total ship computing environments). These types of system are increasingly interconnected via wireless and wireline networks to form systems of systems. A challenging requirement for these DRE systems involves supporting a diverse set of quality of service (QoS) properties, such as predictable latency/jitter, throughput guarantees, scalability, 24x7 availability, dependability, and security that must be satisfied simultaneously in real-time. Although increasing portions of DRE systems are based on QoS-enabled commercial-off-the-shelf (COTS) hardware and software components, the complexity of managing long lifecycles (often ~15-30 years) remains a key challenge for DRE developers and system integrators. For example, substantial time and effort is spent retrofitting DRE applications when the underlying COTS technology infrastructure changes. This paper provides two contributions that help improve the development, validation, and integration of DRE systems throughout their lifecycles. First, we illustrate the challenges in creating and deploying QoS-enabled component middleware-based DRE applications and describe our approach to resolving these challenges based on a new software paradigm called Model Driven Middleware (MDM), which combines model-based software development techniques with QoS-enabled component middleware to address key challenges faced by developers of DRE systems - particularly composition, integration, and assured QoS for end-to-end operations. Second, we describe the structure and functionality of CoSMIC (Component Synthesis using Model Integrated Computing), which is an MDM toolsuite that addresses key DRE application and middleware lifecycle challenges, including partitioning the components to use distributed resources effectively, validating software configurations, assuring multiple simultaneous QoS properties in real-time, and safeguarding against rapidly changing technology.

A Platform-Independent Component Modeling Language for Distributed Real-time and Embedded Systems

This paper provides two contributions to the study of developing and applying domain-specific modeling languages (DSMLS) to distributed real-time and embedded (DRE) systems - particularly those systems using standards-based QoS-enabled component middleware. First, it describes the platform-independent component modeling language (PICML), which is a DSML that enables developers to define component interfaces, QoS parameters and software building rules, and also generates descriptor files that facilitate system deployment. Second, it applies PICML to an unmanned air vehicle (UAV) application portion of an emergency response system to show how PICML resolves key component-based DRE system development challenges. Our results show that the capabilities provided by PICML - combined with its design and deployment-time validation capabilities - eliminates many common errors associated with conventional techniques, thereby increasing the effectiveness of applying QoS-enabled component middleware technologies to the DRE system domain.

Component-Based System Integration via (Meta)Model Composition

This paper provides three contributions to the study of functional integration of distributed enterprise systems. First, we describe the challenges associated with functionally integrating the software of these systems. Second, we describe how the composition of domain-specific modeling languages (DSMLs) can simplify the functional integration of enterprise distributed systems by enabling the combination of diverse middleware technologies. Third, we demonstrate how composing DSMLs can solve functional integration problems by reverse engineering an existing CORBA component model (CCM) system and exposing it as Web service(s) to Web clients who use these services. This paper shows that functional integration done using (meta)model composition provides significant benefits with respect to automation, reusability, and scalability compared to conventional integration processes and methods

CoSMIC: addressing crosscutting deployment and configuration concerns of distributed real-time and embedded systems

This paper describe a model-driven development (MDD) toolsuite called <i>Component Synthesis using Model-Integrated Computing</i> (CoSMIC), which configures and deploys distributed real-time and embedded (DRE) systems using quality of service (QoS)-enabled component middleware. We show how CoSMIC addresses crosscutting configuration and deployment concerns at multiple layers of middleware and applications in component-based DRE systems. We also discuss how CoSMIC leverages model checking and analysis tools to validate key properties for configured DRE systems.

Physical Assembly Mapper: A Model-Driven Optimization Tool for QoS-Enabled Component Middleware

This paper provides four contributions to the study of optimization techniques for component-based distributed real-time and embedded (DRE) systems. First, we describe key challenges of designing component-based DRE systems and identify key sources of overhead in a typical component-based DRE system from the domain of shipboard computing. Second, we describe a class of optimization techniques applicable to the deployment of component-based DRE systems. Third, we describe the physical assembly mapper (PAM), which is a model-driven optimization tool that implements these techniques to reduce footprint. Fourth, we evaluate the benefits of these optimization techniques empirically and analyze the results. Our results indicate that the deployment-time optimization techniques in PAM provides significant benefits, such as 45% improvement in footprint, when compared to conventional component middleware technologies.

WEAVING DEPLOYMENT ASPECTS INTO DOMAIN-SPECIFIC MODELS ⁄

Domain-specific models increase the level of abstraction used to develop large-scale component-based systems. Model-driven development (MDD) approaches (e.g., Model-Integrated Computing and Model-Driven Architecture) emphasize the use of models at all stages of system development. Decomposing problems using MDD approaches may result in a separation of the artifacts in a way that impedes comprehension. For example, a single concern (such as deployment of a distributed system) may crosscut different orthogonal activities (such as component specification, interaction, packaging and planning). To keep track of all entities associated with a component, and to ensure that the constraints for the system as a whole are not violated, a purely model-driven approach imposes extra effort, thereby negating some of the benefits of MDD. This paper provides three contributions to the study of applying aspect-oriented techniques to address the crosscutting challenges of model-driven component-based distributed systems development. First, we identify the sources of crosscutting concerns that typically arise in model-driven development of component-based systems. Second, we describe how aspect-oriented model weaving helps modularize these crosscutting concerns using model transformations. Third, we describe how we have applied model weaving using a tool called the Constraint-Specification Aspect Weaver (C-SAW) in the context of the Platform-Independent Component Modeling Language (PICML), which is a domain-specific modeling language for developing component-based systems. A case study of a joint-emergency response system is presented to express the challenges in modeling a typical distributed system. Our experience shows that model weaving is an effective and scalable technique for dealing with crosscutting aspects of component-based systems development.

QUICKER: A Model-Driven QoS Mapping Tool for QoS-Enabled Component Middleware

This paper provides three contributions to the study of quality of service (QoS) configuration in component-based DRE systems. First, we describe the challenges associated with mapping the platform-independent QoS policies of an application into platform-dependent values of QoS parameters used to configure the behavior of QoS-enabled component middleware. Second, we describe a novel approach that uses model-transformation to map these QoS policies onto component middleware QoS configuration parameters. Third, we demonstrate the use of model-checking to verify the properties of the transformation and automate the synthesis of configuration parameters required to tune the QoS-enabled component middleware. Our results indicate that model-transformation and model-checking provide significant benefits with respect to automation, reusability, verifiability, and scalability of the QoS mapping process compared with conventional middleware configuration techniques