Toward Contention Analysis for Parallel Executing Real-Time Tasks

In measurement-based probabilistic timing analysis, the execution conditions imposed to tasks as measurement scenarios, have a strong impact to the worst-case execution time estimates. The scenarios and their effects on the task execution behavior have to be deeply investigated. The aim has to be to identify and to guarantee the scenarios that lead to the maximum measurements, i.e. the worst-case scenarios, and use them to assure the worst-case execution time estimates. We propose a contention analysis in order to identify the worst contentions that a task can suffer from concurrent executions. The work focuses on the interferences on shared resources (cache memories and memory buses) from parallel executions in multi-core real-time systems. Our approach consists of searching for possible task contenders for parallel executions, modeling their contentiousness, and classifying the measurement scenarios accordingly. We identify the most contentious ones and their worst-case effects on task execution times. The measurement-based probabilistic timing analysis is then used to verify the analysis proposed, qualify the scenarios with contentiousness, and compare them. A parallel execution simulator for multi-core real-time system is developed and used for validating our framework. The framework applies heuristics and assumptions that simplify the system behavior. It represents a first step for developing a complete approach which would be able to guarantee the worst-case behavior

Model Driven Engineering with Capella and AADL

The development of real time embedded equipments is a challenging task that requires the elaboration of multiple models in several domains, notably system, electronics and software, spanning a large spectrum of multiple abstraction levels and viewpoints: structural, behavioral, dependability, etc. These models serve various purposes: specification, design, evaluation or verification and validation. Today, no single modeling language and environment covers all these aspects. While Capella – an open source modeling language and environment for system engineering developed by Thales – fits well to the most early stages of the development process, AADL – the Architecture Analysis and Design Language defined by the Society of Automotive Engineers – provides powerful capabilities to describe and analyze the design artifacts of the software point of view that appear during the latest phase of the design. This is why they have both been selected in the project INGEQUIP of IRT Saint Exupéry. While using different modeling languages for different purpose is perfectly acceptable in a development process, it is important to guarantee that information remain consistent across all models. This is why building a formalized bridge between Capella and AADL is an essential piece of INGEQUIP process. In this paper, after an introduction to the context of INGEQUIP, the high level semantics of Capella and AADL are compared. The mapping used in INGEQUIP between Capella physical models and AADL abstract models is then described. The whole approach is illustrated by some elements coming from the design of TwIRTee – the robotic demonstrator of INGEQUIP – before concluding

Integrated formal verification of safety-critical software

This work presents a formal verification process based on the Systerel Smart Solver (S3) toolset for the development of safety-critical embedded software. In order to guarantee the correctness of the implementation of a set of textual requirements, the process integrates different verification techniques (inductive proof, bounded model checking, test case generation and equivalence proof) to handle different types of properties at their best capacities. It is aimed at the verification of properties at system, design, and code levels. To handle the floating-point arithmetic (FPA) in both the design and the code, an FPA library is designed and implemented in S3. This work is illustrated on an Automatic Rover Protection (ARP) system implemented on-board a robot. Focus is placed on the verification of safety and functional properties and on the equivalence proof between the design model and the generated code

Event-B at work: some lessons learnt from an application to a robot anti-collision function

The technical and academic aspects of the Event-B method, and the abstract description of its application in industrial contexts are the subjects of numerous publications. In this paper, we describe the experience of development engineers non familiar with Event-B to getting to grips with this method. We describe in details how we used the formalism, the refinement method, and its supporting toolset to develop the simple anti-collision function embedded in a small rolling robot. We show how the model has been developed from a set of high-level requirements and refined down to the software specification. For each phase of the development, we explain how we used the method, expose the encountered difficulties, and draw some practical lessons from this experiment

Using Model Checking to Identify Timing Interferences on Multicore Processors

International audienc

Identification of Cytokinin-Responsive Genes Using Microarray Meta-Analysis and RNA-Seq in Arabidopsis

Cytokinins are N6-substituted adenine derivatives that play diverse roles in plant growth and development. We sought to define a robust set of genes regulated by cytokinin as well as to query the response of genes not represented on microarrays. To this end, we performed a meta-analysis of microarray data from a variety of cytokinin-treated samples and used RNA-seq to examine cytokinin-regulated gene expression in Arabidopsis (Arabidopsis thaliana). Microarray meta-analysis using 13 microarray experiments combined with empirically defined filtering criteria identified a set of 226 genes differentially regulated by cytokinin, a subset of which has previously been validated by other methods. RNA-seq validated about 73% of the up-regulated genes identified by this meta-analysis. In silico promoter analysis indicated an overrepresentation of type-B Arabidopsis response regulator binding elements, consistent with the role of type-B Arabidopsis response regulators as primary mediators of cytokinin-responsive gene expression. RNA-seq analysis identified 73 cytokinin-regulated genes that were not represented on the ATH1 microarray. Representative genes were verified using quantitative reverse transcription-polymerase chain reaction and NanoString analysis. Analysis of the genes identified reveals a substantial effect of cytokinin on genes encoding proteins involved in secondary metabolism, particularly those acting in flavonoid and phenylpropanoid biosynthesis, as well as in the regulation of redox state of the cell, particularly a set of glutaredoxin genes. Novel splicing events were found in members of some gene families that are known to play a role in cytokinin signaling or metabolism. The genes identified in this analysis represent a robust set of cytokinin-responsive genes that are useful in the analysis of cytokinin function in plants

Electromagnetic Wave Theory and Applications

Contains table of contents for Section 3, reports on three research projects and a list of publications.California Institute of Technology/Jet Propulsion Laboratory Contract 959548National Aeronautics and Space Administration Grant NAGW-1617National Aeronautics and Space Administration Grant Contract 958461U.S. Navy - Office of Naval Research Grant N00014-92-J-1616U.S. Navy - Office of Naval Research Grant N00014-92-J-4098Digital Equipment Corporation AGMT DTD 11/16/93Joint Services Electronics Program Contract DAAL03-92-C-0001Joint Services Electronics Program Grant DAAH04-95-1-0038MIT Lincoln Laboratory P.O. No. BX-5424U.S. Navy - Office of Naval Research Grant N00014-90-J-1002U.S. Navy - Office of Naval Research Grant N00014-89-J-1019DEMACO Agreement 11/15/93Federal Aviation Administration Grant 94-G-007U.S. Army Cold Regions Research and Engineering Laboratory Contract DACA89-93-K-000