Julio L. Medina

Annotating UML models with non-functional properties for quantitative analysis

This work is motivated by the recent Request For Proposals issued by OMG for a new UML Profile named “Modeling and Analysis of Real-Time and Embedded systems”. The paper describes first some domain concepts for annotating Non-Functional Properties (NFPs), whose focus is on supporting temporal verification of UML-based models. Particular emphasis is given to schedulability and performance analysis for real-time systems. We discuss next some general requirements for NFP annotations and evaluate how the UML profiles for “Schedulability, Performance, and Time Specification” and for “Modeling Quality of Service and Fault Tolerance Characteristics and Mechanisms”, address these requirements. Last but not least, the paper proposes a preliminary framework for describing NFPs by considering the major requirements previously stated and by analyzing some UML mechanisms to attach NFPs to model elements.

Model-based analysis and design of real-time distributed systems with Ada and the UML profile for MARTE

This paper considers the design of hard real-time distributed systems. It uses a model-based approach whose specification is made using UML, a high level standard modelling language. This work describes a tool-aided methodology to enable the assembly and transformation of such design intended models into schedulability analysis models. These analysis models are suitable for the verification of the timing properties of a fully described system in a real-time situation. The description of a real-time situation includes also the knowledge of the load the system is expected to support. In order to annotate the required non-functional properties, and to state other real-time enabling features, the UML profile for Modelling and Analysis of Real-Time and Embedded systems (MARTE), a recent modelling standard of the OMG, has been used. The methodology proposed brings several methodological guidelines to get in tune the generation of Ada applications described by the high level application modelling concepts provided by MARTE, with its corresponding schedulability analysis models. The tool associated to this methodology generates as an output the concrete analysis models used by the MAST set of tools, it invokes MAST, and also recovers the output results back into the high level design UML models.

Generating heterogeneous executable specifications in SystemC from UML/MARTE models

Modeling and analysis of real-time embedded system is becoming an important area of research nowadays. In this context, the UML/MARTE profile has been introduced to support the specification, design, and verification stages in the development process. It provides a wide set of facilities to capture the information required in the refinement steps throughout the design flow. To carry out the actions involved in these design steps, MARTE-based tools and methodologies are required. This paper presents a methodology to automatically generate SystemC heterogeneous executable specifications from generic MARTE models. To generate these specifications, the information included in the MARTE models is extracted to discover the system structure and hierarchy. A subset of the concurrency and communication features of the MARTE profile is used for this purpose. Then, automatic generation of the executable specification is possible. The code implementing the corresponding behavior can be easily integrated into the executable model. This design methodology proposes a refinement flow in order to perform the design steps before deciding the final system implementation.

Ada-CCM: Component-Based Technology for Distributed Real-Time Systems

This paper proposes a technology for the development of distributed real-time component-based applications, which takes advantage of the features that Ada offers for the development of applications with predictable temporal behaviour, and which can be executed in embedded platforms with limited resources. The technology uses the Deployment and Configuration of Compo nent-based Distributed Applications Specification of the OMG for describing the components, the execution platforms and the applications. The framework defined in the Lightweight CCM standard of the OMG is taken as the basis of the internal architecture of the components and the applications. It has been extended with a number of features to make the temporal behaviour of the appli cations predictable. Among these extensions, the usage of CORBA has been replaced by special distributed components, called connectors, which implement the interaction between components by means of predictable and customizable communication services. Besides, special mechanisms have been introduced in the environment to make the threading characteristics of the components config urable. The technology fixes the responsibilities and the knowledge required by each actor involved in the component-based development process, and for each of them it defines the input and output artifacts that they have to manage.

Real-Time Modelling of Distributed Component-Based Applications

This paper presents a modular modelling methodology to formulate the timing behaviour of real-time distributed component-based applications. It allows to build real-time models of the platform resources and software components, which are reusable and independent of the applications that use them. The proposed methodology satisfies the completeness, opacity and composability properties, required to ensure that the complete real-time model of an application, able to predict its temporal behaviour by schedulability analysis or simulation, may be assembled by composition of the real-time models of its constituent parts. These real-time models present a dual descriptor/instance based nature. A class of component, independent of any application, is modelled as a parameterized class-type descriptor, which describes its inherent temporal behaviour and includes references to the real-time models of other hardware/software modules that it requires. An instance of the component in a concrete application context is modelled by an instance-type model, which is generated by assigning concrete values to the parameters and unsolved references of its corresponding descriptor. Instances are formed and combined by automatic tools to build complete analysis models for each specific real-time situation

From composable design models to schedulability analysis with UML and the UML profile for MARTE

Consider the design of hard real-time distributed systems using a model-based and composable approach, in which their specification is made using a high level modelling language like UML. This demo abstract, presents a tool-aided methodology to enable the composition and transformation of such design intended models into also composable schedulability analysis models usable in the verification of the timing properties of the fully composed and loaded systems. In order to annotate the required non-functional properties and state other real-time enabling features, the UML profile for Modeling and Analysis of Real-Time and Embedded systems (MARTE), a recent modeling standard of the OMG, has been used. The methodology comprises several methodological guidelines, specific model transformations, and finally the generation as an output of the concrete schedulability analysis models used by the MAST set of tools, whose results are back annotated into the high level design UML models.

CONTREX: Design of Embedded Mixed-Criticality CONTRol Systems under Consideration of EXtra-Functional Properties

The increasing processing power of todays HW/SW platforms leads to the integration of more and more functions in a single device. Additional design challenges arise when these functions share computing resources and belong to different criticality levels. The paper presents the CONTREX European project and its preliminary results. CONTREX complements current activities in the area of predictable computing platforms and segregation mechanisms with techniques to consider the extra-functional properties, i.e., timing constraints, power, and temperature. CONTREX enables energy efficient and cost aware design through analysis and optimization of these properties with regard to application demands at different criticality levels.

An Ada 2005 Technology for Distributed and Real-Time Component-Based Applications

The concept of interface in Ada 2005 significantly facilitates its usage as the basis for a software components technology. This technology, taking benefit of the resources that Ada offers for real-time systems development, would be suitable for component-based real-time applications that run on embedded platforms with limited resources. This paper proposes a model based technology for the implementation of distributed real-time component-based applications with Ada 2005. The proposed technology uses the specification of components and the framework defined in the LwCCM standard, modifying it with some key features that make the temporal behaviour of the applications executed on it, predictable, and analysable with schedulability analysis tools. Among these features, the dependency on CORBA is replaced by specialized communication components called connectors, the threads required by the components are created and managed by the environment, and interception mechanisms are placed to control their scheduling parameters in a per-transaction basis. This effort aims to lead to a new IDL to Ada mapping, a prospective standard of the OMG.

Enabling Model-Driven Schedulability Analysis in the Development of Distributed Component-Based Real-Time Applications

This work presents a strategy to include temporal behaviour models in deliverable software components in order to develop hard real-time component-based distributed applications, keeping the opacity and composability features that are inherent to the components paradigm. The Deployment and Configuration of Component-based Distributed Applications Specification of the OMG has been extended to include and manage the information that is required to design, analyse, and configure component-based applications with hard real-time requirements. The real-time data added to a component interface enable the application designers to validate scheduling and design decisions without any knowledge of the component internals. Besides, real-time reusable and composable analysis models, developed according to a concrete modelling methodology, are added to each implementation of the component interface. In the context of a concrete application, they are processed by tools to generate the complete real-time analysis model of the application, which is used to evaluate the configuration parameters that guarantee its schedulability. The OMGs MARTE profile provides the conceptual and semantic framework to formulate the real-time behaviour models used in this work.

Integration of a flexible time triggered network in the FRESCOR resource contracting framework

In this paper we overview the integration of a framework that generic ally manages the system resources in the form of contracts, namely the FRESCOR framework, with a flexible network resource. We describe how a network resource, namely FTT-SE, supports the FRESCOR framework services and, likewise, how the network services are made available to the application through the contracting framework. In a designer perspective, we also describe how a typical distributed application can be easily deployed using such a framework.