and MICHAEL MEREDITH Forte Design SystemsWith increasing design complexity, the gap from ESL (Electronic System Level) design to RTL synthesis becomes more and more crucial to many industrial projects. Although several behavioral synthesis tools exist to automatically generate synthesizable RTL code from C/C++/SystemCbased input descriptions and software generation for embedded processors is automated as well, an efficient ESL synthesis methodology combining both is still missing. This article presents SYS-TEMCODESIGNER, a novel SystemC-based ESL tool to automatically optimize a hardware/software SoC (System on Chip) implementation with respect to several objectives. Starting from a SystemC behavioral model, SYSTEMCODESIGNER automatically extracts the mathematical model, performs a behavioral synthesis step, and explores the multiobjective design space using state-of-the-art multiobjective optimization algorithms. During design space exploration, a single design point is evaluated by simulating highly accurate performance models, which are automatically generated from the SystemC behavioral model and the behavioral synthesis results. Moreover, SYSTEMCODESIGNER permits the automatic generation of bit streams for FPGA targets from any previously optimized SoC implementation. Thus SYSTEMCODESIGNER is the first fully automated ESL synthesis tool providing a correct-by-construction generation of hardware/software SoC implementations. As a case study, a model of a Motion-JPEG decoder was automatically optimized and implemented using SYSTEMCODESIGNER. Several synthesized SoC variants based on this model show different tradeoffs between required hardware costs and achieved system throughput, ranging from software-only solutions to pure hardware implementations that reach real-time performance for QCIF streams on a 50MHz FPGA. ACM Reference Format:Keinert, J., Streubühr, M., Schlichter, T., Falk, J., Gladigau, J., Haubelt, C., and Teich, J. 2009. SYSTEMCODESIGNER-An automatic ESL synthesis approach by design space exploration and behavioral synthesis for streaming application.

In this paper, we propose a generalized clustering approach for static data flow subgraphs mapped onto individual processors in Multi-Processor System on Chips (MPSoCs). The goal of clustering is to replace the static data flow subgraph by a single dynamic data flow actor such that the global performance in terms of latency and throughput is optimized. Through our proposed clustering approach, the scheduling of connected static data flow subgraphs can be coordinated with enclosing system representations in a way that systematically exploits the predictability and efficiency of the static data flow model. Thus, the advantages of static data flow subsystems can be exploited in the context of overall system representations that are based on more general models of computation. At the same time, our approach goes significantly beyond previous approaches to synchronous data flow clustering by providing a quasi-static -as opposed to purely-static -scheduling interface between clustered subgraphs and the enclosing systems. This greatly enhances the power of our techniques in terms of avoiding deadlock, increasing the design space for clustering, and providing for integration with more general models of computation. We show benefits of up to 95% performance improvement for real world examples.

Reservoir production can be stimulated by creating hydraulic fractures that effectively facilitate the inflow of hydrocarbons into a well. Considering the effectiveness and safety of the operation, it is desirable to monitor the size and location of the fracture. In this paper we investigate the possibilities of using seismic waves generated by active sources to characterize the fractures. First, we must understand the scattering of seismic waves by hydraulic fractures. For that purpose we use a finite‐difference modeling scheme. We argue that a mechanically open hydraulic fracture can be represented by a thin, fluid‐filled layer. The width or aperture of the fracture is often small compared to the seismic wavelength, which forces us to use a very fine grid spacing to define the fracture. Based on equidistant grids, this results in a large number of grid points and hence computationally expensive problems. We show that this problem can be overcome by allowing for a variation in grid spacing in the finite‐difference scheme to accommodate the large‐scale variation in such a model. Second, we show ultrasonic data of small‐scale hydraulic fracture experiments in the laboratory. At first sight it is difficult to unravel the interpretation of the various events measured. We use the results of the finite‐difference modeling to postulate various possible events that might be present in the data. By comparing the calculated arrival times of these events with the laboratory and finite‐difference data, we are able to propose a plausible explanation of the set of scattering events. Based on the laboratory data, we conclude that active seismic sources can potentially be used to determine fracture size and location in the field. The modeling example of fracture scattering illustrates the benefit of the finite‐difference technique with a variation in grid spacing for comparing numerical and physical experiments.

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