Numerical Simulation of Distributed Dynamic Systems using Hybrid Tools of Intelligent Computing

Developing fast and accurate numerical simulation models for predicting, controlling, designing, and optimizing the behavior of distributed dynamic systems is of interest to many researchers in various fields of science and engineering. These systems are described by a set of differential equations with homogenous or mixed boundary constraints. Examples of such systems are found, for example, in many networked industrial systems. The purpose of the present work is to review techniques of hybrid soft computing along with generalized scaling analysis for the solution of a set of differential equations characterizing distributed dynamic systems. The authors also review reduction techniques. This paves the way to control synthesis of real-time robust realizable controllers.

Emerging Technologies for Industrial Wireless Sensor Networks

The evolution of industrial networks can be summarized as a constant battle to define the universal technology that integrates field devices and applications. Since the Fieldbus wars in the 1980s, diverse wired solutions have been proposed. However, this scenario has been changing due to the introduction of industrial wireless sensor networks. In the last 10 years, the development of deterministic scheduling techniques, redundant routing algorithms, and energy saving issues has brought wireless sensor networks into the industrial domain. This new communication paradigm is governed by a de facto standard, the IEEE 802.15.4, and more recently also by the IEEE 802.15.5. However, there are signs of a new battle on the horizon with the new publicly available specifications of WirelessHART, ISA100.11a, and IEC 62601. In this chapter, to the authors analyze the advantages and drawbacks of these emerging technologies for industrial wireless sensor networks.

Hybrid FlexRay/CAN Automotive Networks

In recent years, the automotive industry has witnessed an exponential growth in the number of vehicular embedded applications, leading to the adoption of distributed implementations for systems in the powertrain and chassis domains. The Controller Area Network (CAN) protocol has been a de facto standard for intra-vehicular communications, while the FlexRay Communication System is being promoted as the future de facto standard for network interconnections of applications related to X-by-wire systems. Due to the characteristics of CAN and FlexRay, the coexistence of both protocols in the same vehicle is expected, leading to the use of gateways to manage the information exchange between electronic control units connected to different network segments. This chapter describes the main characteristics of CAN and FlexRay protocols, surveying the literature addressing schedulability and time analysis in both FlexRay and CAN protocols. The chapter also outlines the state-of-the-art in research about gateways for intra-vehicular communication networks.

Wireless IEEE 802.11-Based Networking Approaches for Industrial Networked Systems

During the last few years, the demand for Real-Time (RT) communication has been steadily increasing due to a wide range of new applications. Remarkable examples are VoIP (Voice over IP) and Networked Control Systems (NCS). For such RT applications, the support of timely communication services is one of the major requirements. The purpose of this chapter is to survey the state-of-the-art on RT communication in CSMA-based networks and to identify the most suitable approaches to deal with the requirements imposed by next generation communication systems. This chapter focuses on one of the most relevant solutions that operate in shared broadcast environments, according to the CSMA medium access protocol, the IEEE 802.11 standard. From this survey, it becomes clear that traditional CSMA-based networks are not able to deal with the requirements imposed by next generation communication systems. More specifically, they are not able to handle uncontrolled traffic sources sharing the same broadcast environment.

Safety Reconfiguration of Embedded Control Systems

The authors study the safety reconfiguration of embedded control systems following component-based approaches from the functional level to the operational level. At the functional level, a Control Component is defined as an event-triggered software unit characterized by an interface that supports interactions with the environment (the plant or other Control Components). They define the architecture of the Reconfiguration Agent, which is modelled by nested state machines to apply local reconfigurations. The authors propose technical solutions to implement the agent-based architecture by defining UML meta-models for both Control Components and also agents. At the operational level, a task is assumed to be a set of components having some properties independently from any real-time operating system. To guarantee safety reconfigurations of tasks at run-time, the authors define service and reconfiguration processes for tasks and use the semaphore concept to ensure safety mutual exclusions. They apply the priority ceiling protocol as a method to ensure the scheduling between periodic tasks with precedence and mutual exclusion constraints.

Merging and Splitting Petri Net Models within Distributed Embedded Controller Design

Design of distributed embedded controllers can benefit from the adoption of a model-based development attitude, where Petri nets modeling can provide support for a comprehensive specification and documentation of the system together with verification capabilities and automatic deployment into implementation platforms. This chapter presents a Petri nets-based development flow based on composition and decomposition of Petri net models, using Input-Output Place-Transition Petri nets (IOPT nets) as the underlying formalism, allowing reusability of models in new situations through a net addition operation, as well as partitioning of the model into components using a net splitting operation. Distributed embedded controllers are addressed adding the concept of time domains to IOPT nets. Finally, a tool chain framework is presented supporting the whole development process, from specification to implementation, including property verification, simulation, and automatic code generation for deployment into implementation platforms (considering hardware-based implementation and VHDL coding or software-oriented implementation and C coding).

Expressing and Validating OCL Constraints using Graphs

The definition of the semantics of visual languages, in particular Unified Modeling Language (UML) diagrams, using graph formalism has known a wide success, since graphs fit the multi-dimensional nature of this kind of language. However, constraints written in Object Constraint Language (OCL) and defined on these models are still not well integrated within this graph-based semantics. In this chapter, the authors propose an integrated semantics of OCL constraints within class diagrams, using graph transformation systems. Their contribution is divided into two parts. In the first part, they introduce graph constraint patterns, as the translation into graphs of a subset of OCL expressions. These patterns are validated with experimental examples using the GROOVE toolset. In the second part, the authors define the relation between OCL and UML models within their graph transformation system.

EAST-ADL

EAST-ADL is an Architecture Description Language (ADL) initially defined in several European-funded research projects and subsequently refined and aligned with the more recent AUTOSAR automotive standard. It provides a comprehensive approach for defining automotive electronic systems through an information model that captures engineering information in a standardized form. Aspects covered include vehicle features, requirements, analysis functions, software and hardware components, and communication. The representation of the system’s implementation is not defined in EAST-ADL itself but by AUTOSAR. However, traceability is supported from EAST-ADL’s lower abstraction levels to the implementation level elements in AUTOSAR. In this chapter, the authors describe EAST-ADL in detail, show how it relates to AUTOSAR as well as other significant automotive standards, and present current research work on using EAST-ADL in the context of fully-electric vehicles, the functional safety standard ISO 26262, and for multi-objective optimization.

Multi-Core Embedded Systems

Multiple processors, microcontrollers, or DSPs have been used in embedded systems to distribute control and data flow according to the application at hand. The recent trends of incorporating multiple cores in the same chip significantly expands the processing power of such heterogeneous systems. However, these trends demand new ways of building and programming embedded systems in order to control cost and complexity. In this context, the authors present an overview on multi-core architectures and their inter-core communication mechanisms, dedicated cores used as accelerators, and hardware reconfiguration providing flexibility on today’s multi-core embedded systems. Finally, they highlight tools, frameworks, and techniques for programming multi-cores and accelerators in order to take advantage of their performance in a robust and cost effective manner.

New Optimal Solutions for Real-Time Reconfigurable Periodic Asynchronous OS Tasks with Minimizations of Response Times

This chapter deals with Reconfigurable Uniprocessor embedded Real-Time Systems to be classically implemented by different OS tasks that we suppose independent, asynchronous, and periodic in order to meet functional and temporal properties described in user requirements. The authors define a schedulability algorithm for preemptable, asynchronous, and periodic reconfigurable task systems with arbitrary relative deadlines, scheduled on a uniprocessor by an optimal scheduling algorithm based on the EDF principles and on the dynamic reconfiguration. Two forms of automatic reconfigurations are assumed to be applied at run-time: Addition-Remove of tasks and just modifications of their temporal parameters: WCET and/or Periods. Nevertheless, when such a scenario is applied to save the system at the occurrence of hardware-software faults, or to improve its performance, some real-time properties can be violated. The authors define a new semantic of the reconfiguration where a crucial criterion to consider is the automatic improvement of the system’s feasibility at run-time by using an Intelligent Agent that automatically checks the system’s feasibility after any reconfiguration scenario to verify if all tasks meet the required deadlines. Indeed, if a reconfiguration scenario is applied at run-time, then the Intelligent Agent dynamically provides otherwise precious technical solutions for users to remove some tasks according to predefined heuristic (based on soft or hard task), or by modifying the Worst Case Execution Times (WCETs), periods, and/or deadlines of tasks that violate corresponding constraints by new ones, in order to meet deadlines and to minimize their response time. To handle all possible reconfiguration solutions, they propose an agent-based architecture that applies automatic reconfigurations in order to re-obtain the system’s feasibility and to satisfy user requirements. Therefore, the authors developed the tool RT-Reconfiguration to support these contributions that they apply to a Blackberry Bold 9700 and to a Volvo system as running example systems and we apply the Real-Time Simulator Cheddar to check the whole system behavior and to evaluate the performance of the algorithm (detailed descriptions are available at the Website: http://beru.univ-brest.fr/~singhoff/cheddar). The authors present simulations of this architecture where they evaluate the agent that they implemented. In addition, the authors present and discuss the results of experiments that compare the accuracy and the performance of their algorithm with others.