Calin Glitia

PhD thesis

• Calin Glitia, Optimizations for systematic and intensive signal processing applications on System-on-Chip, November 23, 2009, Science and Technology University of Lille, FRANCE. more...

  Abstract: Intensive signal processing applications appear in many application domains such as video processing or detection systems. These applications handle multidimensional data structures (mainly arrays) to deal with the various dimensions of the data (space, time, frequency). A specification language allowing the direct manipulation of these different dimensions with a high level of abstraction is a key to handling the complexity of these applications and to benefit from their massive potential parallelism. The Array-OL specification language is designed to do just that.
  In this thesis, we introduce an extension of Array-OL to express cycle dependences by the way of uniform inter-repetition dependences. We show that this specification language is able to express the main patterns of computation of the intensive signal processing domain. We discuss also the repetitive modeling of parallel applications, repetitive architectures and uniform mappings of the former to the latter, using the Array-OL concepts integrated into the Modeling and Analysis of Real-time and Embedded systems (MARTE) UML profile.
  High-level data-parallel transformations are available to adapt the application to the execution, allowing to choose the granularity of the flows and a simple expression of the mapping by tagging each repetition by its execution mode : data-parallel or sequential. The whole set of transformations was reviewed, extended and implemented as a part of the Gaspard2 co-design environment for embedded systems. With the introduction of the uniform dependences into the specification, our interest turns also on the interaction between these dependences and the high-level transformations. This is essential in order to enable the usage of the refactoring tools on the models with uniform dependences.
  Based on the high-level refactoring tools, strategies and heuristics can be designed to help explore the design space. We propose a strategy that allows to find good trade-offs in the usage of storage and computation resources, and in the parallelism (both task and data parallelism) exploitation, strategy illustrated on an industrial radar application.

international journals

• Calin Glitia, Pierre Boulet, Eric Lenormand, and Michel Barreteau. Repetitive model refactoring strategy for the design space exploration of intensive signal processing applications, In Jurnal of Systems Architecture, 2011. more...

  Abstract: The efficient design of computation intensive multidimensional signal processing applications requires dealing with three kinds of constraints: those implied by the data dependencies, the non-functional requirements (real-time, power consumption) and resources availability of the execution platform. Modeling and Analysis of Real-time and Embedded systems (MARTE) UML profile through its repetitive structure modeling (RSM) package is well suited to model the inherent parallelism within these applications, a compact representation of parallel execution platforms and the distributive mapping of one on another. The execution of such a specification respects the whole set of constraints defined upon, while the quality of the scheduling is directly linked to the quality of the mapping of the multidimensional structures (data arrays or parallel loop nests) into time and space. We propose here a strategy to use a refactoring tool dedicated to this kind of application that allows to find good trade-offs in the usage of storage and computation resources and in parallelism (both task and data parallelism) exploitation. This strategy is illustrated on an industrial radar application.

• Calin Glitia, Philippe Dumont and Pierre Boulet, Array-OL with delays, a domain specific specification language for multidimensional intensive signal processing, In Multidimensional Systems and Signal Processing, 2009. more...

  Abstract: Intensive signal processing applications appear in many application domains such as video processing or detection systems. These applications handle multidimensional data structures (mainly arrays) to deal with the various dimensions of the data (space, time, frequency). A specification language allowing the direct manipulation of these different dimensions with a high level of abstraction is a key to handling the complexity of these applications and to benefit from their massive potential parallelism. The Array-OL specification language is designed to do just that. We introduce here an extension of Array-OL to deal with states or delays by the way of uniform inter-repetition dependences. We show that this specification language is able to express the main patterns of computation of the intensive signal processing domain.

peer reviewed international conferences

• Calin Glitia, Julien DeAntoni and Frédéric Mallet, Logical time at work: capturing data dependencies and platform constraints, In International Forum for Design Languages (FDL 2009), Septembre 2010, Southampton, UK more...

  Abstract: Data-flow models are convenient to represent signal processing systems. They precisely reflect the data-dependencies and numerous algorithms exist to compute a static schedule that optimizes a given criterion especially for parallel implementations. Once deployed the data-flow models must be refined with constraints imposed by the environment and the execution platform. In this paper, we show how we can model data dependencies supported by multi-dimensional synchronous data flow with logical time and extend these data dependencies with additional logical constraints imposed by the environment. Making explicit these external constraints allows the exploration of further solutions during the scheduling computation.

• Calin Glitia and Pierre Boulet, Interaction between inter-repetition dependences and high-level transformations in array-ol, In Conference on Design and Architectures for Signal and Image Processing (DASIP 2009), Sophia Antipolis, France, September 2009. more...

  Abstract: Systematic signal processing applications appear in many application domains such as video processing or detection systems. These applications handle multidimensional data structures (mainly arrays) to deal with the various dimensions of the data (space, time, frequency). The Array-OL specification language is designed to allow the direct manipulation of these different dimensions with a high level of abstraction. An extension of Array- OL was previously introduced in order to allow the modeling of uniform inter-repetition dependences. This article studies the interaction between these dependences and the high-level transformations designed to allow to adapt the application to the execution, already available on Array-OL.

• Calin Glitia and Pierre Boulet, High Level Loop Transformations for Multidimensional Signal Processing Embedded Applications, In International Symposium on Systems, Architectures, Modeling, and Simulation (SAMOS VIII), Samos, Greece, July 2008. more...

  Abstract: Array-OL specification model is a mixed graphical-textual language designed to model multidimensional intensive signal processing applications. Data and task parallelism are specified directly in the model. High level transformations are defined on this model, allowing the refactoring of an application and furthermore providing directions for optimization. The resemblances between with the wide-known and used Loop transformations lead us to try taking concepts and results from this domain and see how they fit in Array-OL context.

peer reviewed international workshops

• Calin Glitia, Interaction between delays and high-level transformations in array-ol, In 2nd Artist Workshop on Models of Computation and Communication, Eindhoven, Netherlands, July 2008.

talks, presentation or demos

• Calin Glitia, Logical time at work: capturing data dependencies and platform constraints, Synchron 2010: Seventeenth Seminar on Synchronous languages, modeling, and programming, Fréjus, France, November 2010.

• Calin Glitia, Gaspard2: review at the end of ter@ops project - presentation and demo, In Plenary meeting at the end of Ter@ops project, Palaiseau, France, June 2009.

• Calin Glitia, Gaspard2 demo, Workshop on Massively Multiprocessor and Multicore Computers, Rocquencourt, France, 4-5 February 2009.

• Calin Glitia, Optimizations for systematic and intensive signal processing applications on System-on-Chip, EuroDocInfo09 : 2nd Transnational gathering of PhD Students in Computer Science and IT, Mons, Belgium, 22nd-23rd January 2009.

thesis

• Calin Glitia, Code transformations for systematic signal processing and memory size optimizations, Master's thesis, École Normale Supérieure de Lyon, France, 26 June 2006.

• Calin Glitia, A performance analysis on web services for mathematical systems, Dipl.Ing. thesis, "Polytehnica" University of Timisoara, Romania, June 2005.

Resources

• cv in english
• cv en français
• TimeSquare
• Gaspard2

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