Nicolas Hili

PhD of the University of Grenoble

PhD thesis realized in CEA LETI / DACLE and in the SIGMA team of the LIG laboratory

Publications

International Conferences:

A Power Consumption Estimation Approach for Embedded Software Design Using Trace Analysis

Ben Atitallah, Y. and Mottin, J. and Hili, N. and Ducroux, T. and Godet-Bar, G.
IEEE 41st Euromicro Conference on Software Engineering and Advanced Applications (SEAA), Madeira, Portugal
Read the abstractWith the explosion of advanced power control knobs such as dynamic voltage frequency scaling, mastering energy constraints in embedded systems is becoming challenging for software developers. Several power estimation techniques have been proposed over the past years, from electrical level to more abstract models such as SystemC/TLM. They offer various tradeoffs between performance and accuracy, but suffer from a number of shortcomings. They are expensive and time-consuming, requiring intricate models of the architecture and finally, fail to be applied from the software developer perspective. In this paper, we propose a lightweight and cost-effective approach suitable for software developers. It relies on trace analysis and high-level modeling of architectures to perform quick and efficient power consumption estimations without loosing accuracy. This approach is fully supported by a tool and is validated using a simple thermal mitigation case study and checked against physical measurements. We show that, for our case study, the relative error between our tool and real values is 8 in average.Close.

Innovative Key Features for Mastering Model Complexity: Flexilab, a Multimodel Editor Illustrated on Task Modeling

Nicolas Hili and Yann Laurillau and Sophie Dupuy-Chessa and Gaëlle Calvary
7th ACM SIGCHI Symposium on Engineering Interactive Computing Systems (EICS'2015), Duisburg, Germany
Read the abstractModeling Human Computer Interaction (HCI) is nowadays practiced by IT companies. However, it remains a straightforward task that requires some advanced User Interface (UI) modeling tools to ease the design of large-scale models. This includes tackling massive UI models, multiplicity of models, multiplicity of stakeholders and collaborative editing. This paper presents a UI multimodel editor for HCI, illustrated on task modeling. We present innovative key features (genericity, creativity, model conformity, reusability, etc.) to facilitate UI model design and to ease interaction.Close.

A Model-Driven Approach for Embedded System Prototyping and Design

Nicolas Hili and Christian Fabre and Sophie Dupuy-Chessa and Dominique Rieu
IEEE International Symposium on Rapid System Prototyping (RSP'14) (part of ESWEEK'14), New Dehli, India
Read the abstractEmbedded System (ES) development complexity is increasing. This increase has several cumulative sources: some are directly related to constraints on the ES themselves (dependability, compute intensive, resource constraints) while other sources are related to the industrial context of their development (prototyping, early validation, parallelization of developments). Although several Model-Driven Engineering (MDE) processes have been proposed for ES development, most of them are not completely formalized. This has several drawbacks that prevent their use in prototyping where iterations need to be short and focused. Incomplete formalized processes tend to be sidestepped in these situations where quick results are expected to be obtained with limited effort. In this paper we propose a MDE-based process for ES development. This process precisely defines the development tasks and their impact on the models throughout development. In particular we define iterations width and depth for the process that allow for a fined-grained and consistent planning of developments. The short and well defined iterations characterized by the process reduce the gap between rapid prototyping, ad-hoc methods and regular development processes.Close.

Model-Based Platform Composition for Embedded System Design

Nicolas Hili and Christian Fabre and Sophie Dupuy-Chessa and Dominique Rieu and Ivan Llopard
IEEE 8th International Symposium on Embedded Multicore/Many-core Systems-on-Chip (MCSoC'14), Aizu-Wakamatsu, Japan
Acceptance rate: 49/142 (34.5%)
Read the abstractPlatforms are widely used to design embedded systems. They have numerous advantages: separation from its application, industrial rationalization, standardization, division of large development teams. However, their design complexity is growing dramatically due to several sources: the intricate combination of parallelism and heterogeneity in modern architectures; the quest for ever low power consumption and the diversity of sensors/actuators required by modern applications. This complexity prevents straightforward platform design in one step and calls for gradual design by composition and improvement over existing components. However, there is no systematic way of composing them, and there is no clear concept suitable for platform composition. In this paper, we propose two atomic ways of composing platforms, increment and assembly, that allow designers to build platforms gradually thanks to two concepts called world and container.Close.

A Parallel Action Language for Embedded Applications and its Compilation Flow

Llopard, Ivan and Cohen, Albert and Fabre, Christian and Hili, Nicolas
IEEE 17th International Workshop on Software and Compilers for Embedded Systems, Sankt Goar, Germany
Read the abstractThe complexity of Embedded System (ES) development is increasing dramatically. This has several cumulative sources: the intricate combination of data-intensive, computational and control aspects; the ubiquity of parallelism and heterogeneity of modern architectures; and the diversity of target-specific, non-deterministic programming models (e.g., C++ with explicit message passing, OpenCL, VHDL). Model-Driven Engineering (MDE) proposes to manage complexity by raising the level of abstraction for designers and developers, and refining the implementation for a particular context and platform through model transformations. In such frameworks, behavior is often specified by means of Hierarchical State Machines (HSMs) equiped with an action language. However, although such models represent some level of control parallelism through objects and HSMs, data parallelism, compound data, and the exploitation and optimization thereof remains very limited. In this paper, we propose an action language that seamlessly combines HSMs with data parallelism and operations on compound data. It preserves the expressivity of HSM and captures a layout-neutral description of data organisation. It also extends message-passing with an intuitive semantics for this additional paralellism and provides strong foundation for array-based optimisation techniques. We present this language together with a baseline code generation flow to enable the production of efficient, low-level imperative code.Close.

Efficient Embedded System Development: A Workbench for an Integrated Methodology

Nicolas Hili and Christian Fabre and Sophie Dupuy-Chessa and Stéphane Malfoy
ERTS2 2012, Toulouse, France
Acceptance rate: 90/165 (54.5%)
Read the abstractThe scientific foundations of embedded system development associate two disciplines that have largely grown on their own: computer science and electrical engineering. This superposition of two domains with little common ground raises a number of industrial issues in team work organisation, sound progress tracking, and cooperation between these different skills and cultures. In this paper we introduce HOE2, an integrated MDE method for embedded system development that is organised around a set of limited yet powerful artefacts. We describe how HOE² can address the issues faced during development of mixed HW/SW systems and present the first version of a tool dedicated to its instrumentation.Close.

National Conferences:

HOE2, une méthode intégrée pour le développement des systèmes embarqués

Nicolas Hili and Christian Fabre and Dominique Rieu and Sophie Dupuy-Chessa and Stéphane Malfoy
XXXème Congrès Inforsid'2012, Montpellier, France
Acceptance rate: 45/87 (51.7%)
Read the abstractThis paper presents HOE2, a method dedicated to embedded system development, a field where the integration of an application and its platform is omnipresent. The organisation of its developments is comparable to the Y-cycle. One of its main aspects is a clear distinction between application development and platform development. The two largely decoupled developments meet in a number of points clearly identified, where the exchanged information is precisely defined. This permits a good synchronisation of two mostly independent teams that shall nevertheless cooperate towards the development of a common embedded system.Close.

Miscellaneous:

How to Efficiently and Rapidly Build Graphical Modelling Editors

Nicolas Hili
Eclipse DemoCamps, Xerox Research Centre Europe
Read the abstractNowadays, graphical modelling tools are increasingly used by embedded system designers. Existing open source and commercial tools allow designing graphical modelling editors based on different approaches e.g. declarative, generative or runtime-oriented. In the framework of the tooling of an embedded system design method, we were especially interested in three open source tools: Graphical Modelling Framework (GMF), Papyrus and Graphiti. After arguing our choice of using Graphiti based on our own feedback, we present its architecture and features. Three video-based tutorials guide this presentation and illustrate how to efficiently and rapidly build graphical modelling editors.Close.

Divide and Conquer: Separation of Concerns to Parallelize Developments

Nicolas Hili and Christian Fabre and Sophie Dupuy-Chessa and Dominique Rieu
Summer School on Cyber-Physical Systems, Grenoble, France
Read the abstractNous présentons HOE2, une méthode dédiée au développement de systèmes embarqués, domaine où les problématiques d'intégration entre l'application et la plate-forme sont omniprésentes. HOE2 s'appuie sur une conception orientée plate-forme en l'étendant un peu plus en introduisant la composition de platesformes au sein d'un processus fractal. Le processus de la méthode HOE2 permet de prendre en compte la composition de plates-formes simples en une plateforme plus complexe, permettant ainsi de construire la solution désirée au développement d'un système embarqué par raffinement, augmentant sensiblement l'efficacité de la parallélisation des développements.Close.

Diviser pour mieux régner : le cas du développement des systèmes embarqués

Nicolas Hili
16ème Journées Nationales du Réseau Doctoral en Micro-Nanoélectronique, Grenoble, France
Read the abstractNous présentons HOE2, une méthode dédiée au développement de systèmes embarqués, domaine où les problématiques d'intégration entre l'application et la plate-forme sont omniprésentes. HOE2 s'appuie sur une conception orientée plate-forme en l'étendant un peu plus en introduisant la composition de platesformes au sein d'un processus fractal. Le processus de la méthode HOE2 permet de prendre en compte la composition de plates-formes simples en une plateforme plus complexe, permettant ainsi de construire la solution désirée au développement d'un système embarqué par raffinement, augmentant sensiblement l'efficacité de la parallélisation des développements.Close.

Heterogeneous Multicore Application Design HOE2: Highly Heterogeneous Object-Oriented Efficient Engineering

Nicolas Hili and Christian Fabre and Sophie Dupuy-Chessa and Dominique Rieu
Journée doctorants du LIG 2013, Grenoble, France
Read the abstractNous présentons HOE2, une méthode dédiée au développement de systèmes embarqués, domaine où les problématiques d'intégration entre l'application et la plate-forme sont omniprésentes. HOE2 s'appuie sur une conception orientée plate-forme en l'étendant un peu plus en introduisant la composition de platesformes au sein d'un processus fractal. Le processus de la méthode HOE2 permet de prendre en compte la composition de plates-formes simples en une plateforme plus complexe, permettant ainsi de construire la solution désirée au développement d'un système embarqué par raffinement, augmentant sensiblement l'efficacité de la parallélisation des développements.Close.