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In this paper an embedded system for the pollution control in automobiles is described. In particular, the focus is on the description of the control algorithm, which receives, as an input, a signal from a MEMS accelerometer and uses it to control the fuel injection rate, in order to reduce the toxic emissions from the exhaust gases. A DSP implementation and simulation results of the same are detailed
Fabry-Perot interferometry (FPI) originally invented for spectroscopy is now evolving as a basic technology for ultra-fine dimensional stabilization and measurement. To this end, the light path length of an optical cavity and the wavelength of a laser source injected into the cavity have to be each other tuned through a set of frequency and/or displacement actuators driven by a sharp and narrow signal...
Embedded systems have specific real-time requirements that led to the development of dedicated communication protocols. Such systems must face increasing communication needs and the evolution of switched Ethernet architecture. But moving from existing dedicated field-busses architectures to new Ethernet based architectures is not always feasible, due to industrial constraints. In this paper, we compare...
Because a real-time system combines control and data processing designers specify it using different languages. Such systems are often distributed and the problem is to obtain a distributed implementation from these distinct specifications. Indeed, the method based on separated code generation and manual distribution leads to inconsistent implementations. We propose to unify all these specifications...
Controller area network (CAN) is nowadays widespread in distributed embedded systems due to its electrical robustness, low price, and deterministic access delay. However, its use in safety-critical applications has been controversial due to dependability limitations. In particular, in a CAN bus there are multiple components such that a single fault of any of them can prevent the communication capabilities...
Embedded electronic communication systems play a vital role in the future development of automotive systems. For successful application developments new test and diagnosis solutions for these distributed systems are required. This paper presents solutions for the stimulus generation of test systems based on a remote test under the stringent constraints of the automotive industry. We elaborate a flexible...
The MatPLC is an international project to develop a program similar to a PLC (programmable logic controller) for POSIX operating systems. It is an open source application consisting of a core, generic modules, and tools for creating custom modules. Since many control and monitoring systems are distributed in nature, they require that the application be running on an embedded system capable of withstanding...
Coordinated atomic (CA) action is a widely used approach to structuring concurrent activities in distributed embedded applications. Recovery from failures is one of its major concerns. Despite the intuitive simplicity, reasoning about failure recovery in CA actions is rather complex because of the interaction between various system components. This paper proposes an approach based on timed CSP for...
In current embedded system design practice, only few architectural solutions and mappings of the functionalities of a system on the architecture's components are examined. This paper presents an optimization-based method and the associated tool developed to help designers take architectural decisions. The principle of this approach is to efficiently explore the design space and to dynamically provide...
In-vehicle embedded systems typically consist of a set of nodes exchanging applicative data ("signals") through a stack of communication protocols that includes a middleware layer. On each node, tasks, both applicative and middleware level, are subject to deadline constraints. Furthermore, signals must be produced sufficiently recently for being safely consumed on the receiver end (so-called...
This paper presents an architecture to build distributed embedded real-time systems in the RTLinux-GPL platform. The architecture (built in a layered fashion) has being built around open source projects ranging from Ethernet drivers to a CORBA environment. The paper focuses on those layers that give support for QoS and real-time networking over Ethernet networks. The main ideas are: to accomplish...
This paper presents the planned and on-going activities inside the FORDESIGN research project, funded by the Portuguese FCT (Foundation for Science and Technology), whose main objective is to foster the effective use of formal methods for embedded systems co-design. The project proposes a methodology where the use-cases are used as a starting point, not only for capturing requirements but also to...
The embedded real-time development community is investigating different approaches in order to provide modularity and reuse features for system design in this area, as well as a more appropriate mapping technique between requirements and implementation. The Java technology is very promising for this community, mainly after the research efforts on its real-time extension RTSJ-real-time specification...
Embedded systems have specific real-time requirements that led to the development of dedicated communication protocols. Such systems often face increasing communication needs and the integration of switched Ethernet architecture. But moving from existing dedicated field-buses architectures to new Ethernet based architectures is not always easily feasible, due to industrial constraints. In this paper,...
This paper presents the object-oriented platform-based design process for embedded real-time systems (SEEP). More specifically, it includes a case study to highlight the main design steps proposed by SEEP. Details regarding embedded system modeling and its transition to the programming level are presented. Moreover, it describes the embedded system generation and provides data obtained from the hardware...
The use of distributed computing architectures has become commonplace in complex embedded systems with potential advantages, for example, in terms of scalability, dependability and maintainability. One particular area in which that trend can be witnessed is mobile autonomous robotics in which several sensors and actuators are interconnected by means of a control network. In this paper we address one...
Recent developments in signal processing, pattern recognition, neural networks and powerful (low-cost) embedded processors allow including speech processing for human-machine interaction in consumer equipment. In this paper we present a compact system for vowels and small vocabulary recognition, its orientation being consumer applications, where cost is of paramount importance. In this case, the speech...
Time-triggered systems are advantageous for embedded applications, when determinism, hard real-time behavior, and a straightforward way for certification are required. However, when it comes to flexibility, time-triggered systems often require that possible extensions have been planned in advance, which makes it difficult to apply unforeseen changes to such a system. This paper presents an approach...
A reported liability of the controller area network protocol is that it does not provide a clock synchronization service. Therefore, whenever a CAN-based distributed embedded system requires its nodes to have a common time base, clock synchronization has to be implemented by means of an external mechanism. In a previous work, we proposed a fault-tolerant and high-precision clock synchronization protocol...
Dynamic voltage scaling (DVS) is a technique used in modern microprocessors operated by battery to set voltage and frequency levels at proper values that meet performance requirements while minimizing energy consumption. Most of the present work on DVS management, however, is based on simplistic assumptions about the hardware characteristics that limit the real applicability of the proposed algorithms...
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