System-Level Modeling, Analysis and Code Generation: Object Recognition Case Study

International audienceOne of the most important challenges in complex embedded systems design is developing methods and tools for modeling and analyzing the behavior of application software running on multi-processor platforms. We propose a tool-supported flow for systematic and compositional construction of mixed software/hardware system models. These models are intended to represent, in an operational way, the set of timed executions of parallel application software statically mapped on a multi-processor platform. As such, system models will be used for performance analysis using simulation-based techniques as well as for code generation on specific platforms. The construction of the system model proceeds in two steps. In the first step, an abstract system model is obtained by composition and specific transformations of (1) the (untimed) model of the application software, (2) the model of the platform and (3) the mapping between them. In the second step, the abstract system model is refined into concrete system model, by including specific timing constraints for execution of the application software, according to chosen mapping on the platform. We illustrate the system model construction method and its use for performance analysis and code generation on an object recognition application provided by Hellenic Airspace Industry. This case study is build upon the HMAX models algorithm [RP99] and is looking at significant speedup factors. This paper reports results obtained on different system model configurations and used to determine the optimal implementation strategy in accordance to hardware resources

XFolders: A Flexible Workflow System based on Electronic Circulation Folders

We present a flexible light-weight document-centered workflow system, called XFolders, that breaks physical and organisational boundaries allowing users across distributed virtual organizations to flexibly collaborate and share documents. The paradigm underlying XFolders is the well known, and widely adopted, internal office circulation envelope. We show how XFolders combines the simplicity of this metaphor with the power and the benefits of today's networked computers, in terms of speed, distance bridging and support. In particular, we show how in XFolders documents can be migrated across organizations hidden by firewalls and how we deal with scalability and dynamicity issues

Memory efficient hybrid algebraic solvers for linear systems arising from compressible flow

International audienceThis paper deals with the solution of sparse linear systems arising from design optimization in computational fluid dynamics. In this approach, a linearization of the discretized compressible Navier-Stokes equations is built, in order to evaluate the sensitivity of the entire flow with respect to each design parameter. This requires an efficient and robust parallel linear solver, to generate the exact flow derivatives: from the algebraic decomposition of the input matrix, a hybrid robust direct/iterative solver is generally defined with a Krylov subspace method as accelerator, a domain decomposition method as preconditioner and a direct method as subdomain solver. The goal of this paper is to reduce the memory requirements and indirectly, the computational cost at different steps of this scheme. To this end, we use a grid-point induced block approach for the data storage and the partitioning part, a Krylov subspace method based on the restarted GMRES accelerated by deflation, a preconditioner formulated with the restricted additive Schwarz method and an aerodynamic/turbulent fields split at the subdomain level. Numerical results are presented with industrial test cases to show the benefits of these choices

Smart Multicore Embedded Systems

This book provides a single-source reference to the state-of-the-art of high-level programming models and compilation tool-chains for embedded system platforms. The authors address challenges faced by programmers developing software to implement parallel applications in embedded systems, where very often they are forced to rewrite sequential programs into parallel software, taking into account all the low level features and peculiarities of the underlying platforms. Readers will benefit from these authors’ approach, which takes into account both the application requirements and the platform specificities of various embedded systems from different industries. Parallel programming tool-chains are described that take as input parameters both the application and the platform model, then determine relevant transformations and mapping decisions on the concrete platform, minimizing user intervention and hiding the difficulties related to the correct and efficient use of memory hierarchy and low level code generation

Xpect: A Generic Framework for Electronic Commerce

Electronic commerce is emerging as one of the main application domains on the Internet and the WWW and promises to change radically the relationship between customers, retailers and service providers. However, for this to happen, electronic commerce must become effectively a better way of selling goods and services than the traditional channels. This requires a suitable infrastructure for developing electronic commerce applications that meet the needs of both customers and providers; for instance, multiparty negotiations should be supported, while restrictions on payment methods should as much as possible be banned. The current capabilities for developing electronic commerce software fall short of such requirements. To contribute to the solution of this problem, we introduce here Xpect, a generic framework for the development of electronic commerce applications that provides powerful agent-based capabilities for the coordination of multiple services and the intermediation and the negotiation among multiple parties