A. James Clark School of Engineering
Permanent URI for this communityhttp://hdl.handle.net/1903/1654
The collections in this community comprise faculty research works, as well as graduate theses and dissertations.
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Item Integrated Software Synthesis for Signal Processing Applications(2006-04-26) Ko, Ming-Yung; Bhattacharyya, Shuvra S.; Electrical Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Signal processing applications usually encounter multi-dimensional real-time performance requirements and restrictions on resources, which makes software implementation complex. Although major advances have been made in embedded processor technology for this application domain -- in particular, in technology for programmable digital signal processors -- traditional compiler techniques applied to such platforms do not generate machine code of desired quality. As a result, low-level, human-driven fine tuning of software implementations is needed, and we are therefore in need of more effective strategies for software implementation for signal processing applications. In this thesis, a number of important memory and performance optimization problems are addressed for translating high-level representations of signal processing applications into embedded software implementations. This investigation centers around signal processing-oriented dataflow models of computation. This form of dataflow provides a coarse grained modeling approach that is well-suited to the signal processing domain and is increasingly supported by commercial and research-oriented tools for design and implementation of signal processing systems. Well-developed dataflow models of signal processing systems expose high-level application structure that can be used by designers and design tools to guide optimization of hardware and software implementations. This thesis advances the suite of techniques available for optimization of software implementations that are derived from the application structure exposed from dataflow representations. In addition, the specialized architecture of programmable digital signal processors is considered jointly with dataflow-based analysis to streamline the optimization process for this important family of embedded processors. The specialized features of programmable digital signal processors that are addressed in this thesis include parallel memory banks to facilitate data parallelism, and signal-processing-oriented addressing modes and address register management capabilities. The problems addressed in this thesis involve several inter-related features, and therefore an integrated approach is required to solve them effectively. This thesis proposes such an integrated approach, and develops the approach through formal problem formulations, in-depth theoretical analysis, and extensive experimentation.Item FASTER DISPLAY OF MECHANICAL ASSEMBLIES BY DETERMINATION OF PART VISIBILITY(2004-05-04) Ou, Jeremy; Magrab, Edward B; Mechanical EngineeringWe present algorithms that greatly decrease the time it takes to display a large number of 3-D mechanical part assemblies by removing all interior parts that cannot be viewed from any viewing angle. The algorithms are based on the minimum axis-aligned bounding box of each part, which avoids complicated computations often needed to determine the interactions of the geometry of the parts. The major contribution of this work is the use of exterior traces of cross sections of the bounding boxes to determine the parts' visibility. It is shown that the processing time increases almost linearly with the number of parts in an assembly of parts. A test on an assembly composed of 490 parts shows that the algorithms decrease the display time by a factor of two while only incorrectly identifying two of these parts as invisible when they should have been identified as visible.