191 research outputs found
A model-based approach to the development of distributed control systems
Distributed Control Systems (DCS) are a class of application with specific characteristics. This type of system is used in industrial environments to control manufacturing processes. Usually they comprise a
controller, a fieldbus network, and a set of Of-The-Shelf (OTS) components, interfacing process signals with real-time QoS requirements. In this paper we present a Model Driven Development (MDD) method that targets this category of systems. This method focuses on the critical stages of DCS development. Namely, the specification of system requirements, the choice of OTS modules and fieldbus system, and the validation of the
design using real-time analysis tools. This MDD method uses the Unified modelling Language (UML) as support notation, including the extensions defined in the UML Profile for Schedulability, Performance and Time Specification.Fundação para a Ciência e Tecnologia; FEDER – Project METHODES (POSI/37334/CHS/2001)
Network Interface Design for Network-on-Chip
In the culture of globalized integrated circuit (IC, a.k.a chip) production, the use of Intellectual Property (IP) cores, computer aided design tools (CAD) and testing services from un-trusted vendors are prevalent to reduce the time to market. Unfortunately, the globalized business model potentially creates opportunities for hardware tampering and modification from adversary, and this tampering is known as hardware Trojan (HT). Network-on-chip (NoC) has emerged as an efficient on-chip communication infrastructure. In this work, the security aspects of NoC network interface (NI), one of the most critical components in NoC will be investigated and presented. Particularly, the NI design, hardware attack models and countermeasures for NI in a NoC system are explored.
An OCP compatible NI is implemented in an IBM0.18ìm CMOS technology. The synthesis results are presented and compared with existing literature. Second, comprehensive hardware attack models targeted for NI are presented from system level to circuit level. The impact of hardware Trojans on NoC functionality and performance are evaluated. Finally, a countermeasure method is proposed to address the hardware attacks in NIs
An Optimal Query Assignment for Wireless Sensor Networks
A trade-off between two QoS requirements of wireless sensor networks: query
waiting time and validity (age) of the data feeding the queries, is
investigated. We propose a Continuous Time Markov Decision Process with a drift
that trades-off between the two QoS requirements by assigning incoming queries
to the wireless sensor network or to the database. To compute an optimal
assignment policy, we argue, by means of non-standard uniformization, a
discrete time Markov decision process, stochastically equivalent to the initial
continuous process. We determine an optimal query assignment policy for the
discrete time process by means of dynamic programming. Next, we assess
numerically the performance of the optimal policy and show that it outperforms
in terms of average assignment costs three other heuristics, commonly used in
practice. Lastly, the optimality of the our model is confirmed also in the case
of real query traffic, where our proposed policy achieves significant cost
savings compared to the heuristics.Comment: 27 pages, 20 figure
Evaluation of SNMP-like protocol to manage a NoC emulation platform
International audience—The Networks-on-Chip(NoCs) are currently the most appropriate communication structure for many-core embedded systems. AnFPGA-based emulation platform can drastically reduce the time needed to evaluate a NoC, even if it is composed by tens or hundreds of distributed components. These components should be timely managed in order to execute an evaluation traffic scenario. There is a lack of standard protocols to drive FPGA-based NoC emulators. Such protocols could ease the integration of emulation components developed by different designers. In this paper, we evaluate a light version of SNMP (Simple Network Management Protocol) to manage an FPGA-based NoC emulation platform. The SNMP protocol and its related components are adapted to a hardware implementation. This facilitates the configuration of the emulation nodes without FPGA-resynthesis, as well as the extraction of emulation results. Some experiments highlight that this protocol is quite simple to implement and very efficient for a light resources overhead
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