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University: ENSEM-INPL Nancy This page presents the past and ongoing research activities of the TRIO
team (Real Time and Inter Operability) performed with OPNET simulation
tool.
Research context
REMPLI The TRIO team is one of the partners of the European research project REMPLI (Real-Time Energy Management via Powerlines and Internet). The REMPLI project aims at creating a distributed infrastructure suitable for real-time data collection, data processing for billing, statistics and planning, management of the distributed network, energy loss detection and inclusion of add-on services, like domotics.The OPNET network simulation tool, already used in other TRIO team projects, was the chosen workbench for evaluating the performances of the system developed in REMPLI project. As this system relies in the powerline medium as the type of data communication, it was necessary to integrate a Physical Layer Emulator (developed by another partner) into OPNET, through the development of a shared library called from the OPNET Framework. This integration permits therefore, to simulate in OPNET the physical events of the powerline medium.
Simulation results of some basic models developed in OPNET confirmed preliminary theoretical works done in REMPLI. Currently, this work continues with the simulation in OPNET of the different Network Layer proposals, which will permit to create a specification of an optimized Network Layer for the REMPLI protocol stack.
Simulation of (m,k)-firm scheduling algorithms Opnet simulation tool has been used to evaluate the performance of scheduling algorithms used in packets switched networks. We have not used the OPNET Standard library and we have instead built our own models (nodes, flows generators, routers) that we have used in simulations.We have implemented several scheduling algorithms such as DBP (Distance Based Priority) published in 1995 in [Hamdaoui95] and an improved version called Matrix-DBP [Poggi03] for periodic tasks with or without jitter. We have been also interested in fair queuing algorithms such as WFQ (Weighted Fair Queueing) and its variants. We have implemented our algorithm (m,k)-WFQ that extends WFQ algorithm to take into account the (m,k)-firm timing constraints [Hamdaoui95] of real-time loss-tolerant flows. Currently, we are interested in integrating (m,k)-WFQ algorithm into the OPNET Standard Library to be used as a standard model like WFQ, Round Robin and other scheduling discipline. More explanation of this work could be found within some publications presented in the following webpage: http://www.loria.fr/~akoubaa/publication.htm References [Hamdoui95] M. Hamdaoui and P. Ramanathan, "A Dynamic Priority Assignment Technique for Streams with (m, k)-Firm Deadlines", IEEE Transactions on Computers, Vol. 44, No. 4, Dec.1995, pp. 1443-1451.
[Poggi03] Poggi, E.-M., Y.-Q. Song, A. Koubaa, Z. Wang, "Matrix-DBP For (m, k)-firm Real-Time Guarantee", Conference of Real Time Systems, Paris (France), Apr. 2003, pp457-482.
VACANS VACANS (Validation of CAN based Systems) is a tool to analyze and validate operational Architectures of CAN (Controller Area Network) based distributed real-time applications. To validate by means of simulation, an OPNET model of such OA was developed. More in details, VACANS models the CAN physical medium, the Intel 82527 CAN controller and a simple message generation scheme; this allows to obtain answer times, optimal data rates and other statistics as the frame collision number. ALITA (Architecture description Language Integrating Task Algorithm) extends the VACANS application model to take into account more complex mechanisms as concurrence for cpu, task synchronization and some basic OS primitives (send_message, read_port, etc.). In counterpart, the physical bus and the network controller models rest the same.AEE The TRIO team is one of the partners of the French research project AEE (Embedded Electronic Architecture). Purpose of this project is the definition of a standard language (AIL), common to car manufacturers and to devices suppliers, which allows the description of the various levels of embedded car systems architectures (FA, HA and AO). From this description it is possible to make validation tests on various AO's configurations by means of simulations. For this purpose, we developed a tool that generates an OPNET model of the system using the AIL description of an OA and allows to obtain statistics on jitters, end to end response times, bus loads and cpu loads. This tool generates an OPNET model of an OA, composed by a set of nodes connected by a CAN bus. To model the tasks and messages management, we respected the OSEK/VDX standard, an operating system currently used in this kind of applications.SimulArchi The problem of the modeling methodology specification is treated in a working cooperation with PSA-Peugeot Citroen Company (SimulArchi). The goals are validation and optimization of the automated architectures in the industrial domain (e.g. the PSA motor factory). Validation process stands on a simulation approach to prove temporal properties, reliability, interoperability and performances. The OPNET tool is used to implement a minimal library of generic models composing the automated manufacturing system architecture. A model of painting car factory was realized using this library. Simulation of this model will allow us to confirm methodology and to identify the most significant performances indicators. |