20,641 research outputs found

    Spectrum of Sizes for Perfect Deletion-Correcting Codes

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    One peculiarity with deletion-correcting codes is that perfect tt-deletion-correcting codes of the same length over the same alphabet can have different numbers of codewords, because the balls of radius tt with respect to the Levenshte\u{\i}n distance may be of different sizes. There is interest, therefore, in determining all possible sizes of a perfect tt-deletion-correcting code, given the length nn and the alphabet size~qq. In this paper, we determine completely the spectrum of possible sizes for perfect qq-ary 1-deletion-correcting codes of length three for all qq, and perfect qq-ary 2-deletion-correcting codes of length four for almost all qq, leaving only a small finite number of cases in doubt.Comment: 23 page

    OPTIMAL AREA AND PERFORMANCE MAPPING OF K-LUT BASED FPGAS

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    FPGA circuits are increasingly used in many fields: for rapid prototyping of new products (including fast ASIC implementation), for logic emulation, for producing a small number of a device, or if a device should be reconfigurable in use (reconfigurable computing). Determining if an arbitrary, given wide, function can be implemented by a programmable logic block, unfortunately, it is generally, a very difficult problem. This problem is called the Boolean matching problem. This paper introduces a new implemented algorithm able to map, both for area and performance, combinational networks using k-LUT based FPGAs.k-LUT based FPGAs, combinational circuits, performance-driven mapping.

    System Synthesis for Networks of Programmable Blocks

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    The advent of sensor networks presents untapped opportunities for synthesis. We examine the problem of synthesis of behavioral specifications into networks of programmable sensor blocks. The particular behavioral specification we consider is an intuitive user-created network diagram of sensor blocks, each block having a pre-defined combinational or sequential behavior. We synthesize this specification to a new network that utilizes a minimum number of programmable blocks in place of the pre-defined blocks, thus reducing network size and hence network cost and power. We focus on the main task of this synthesis problem, namely partitioning pre-defined blocks onto a minimum number of programmable blocks, introducing the efficient but effective PareDown decomposition algorithm for the task. We describe the synthesis and simulation tools we developed. We provide results showing excellent network size reductions through such synthesis, and significant speedups of our algorithm over exhaustive search while obtaining near-optimal results for 15 real network designs as well as nearly 10,000 randomly generated designs.Comment: Submitted on behalf of EDAA (http://www.edaa.com/

    Packing and covering in combinatorics

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    The tree packing conjecture for trees of almost linear maximum degree

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    We prove that there is c>0c>0 such that for all sufficiently large nn, if T1,,TnT_1,\dots,T_n are any trees such that TiT_i has ii vertices and maximum degree at most cn/logncn/\log n, then {T1,,Tn}\{T_1,\dots,T_n\} packs into KnK_n. Our main result actually allows to replace the host graph KnK_n by an arbitrary quasirandom graph, and to generalize from trees to graphs of bounded degeneracy that are rich in bare paths, contain some odd degree vertices, and only satisfy much less stringent restrictions on their number of vertices.Comment: 150 pages, 4 figure

    Selected Papers in Combinatorics - a Volume Dedicated to R.G. Stanton

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    Professor Stanton has had a very illustrious career. His contributions to mathematics are varied and numerous. He has not only contributed to the mathematical literature as a prominent researcher but has fostered mathematics through his teaching and guidance of young people, his organizational skills and his publishing expertise. The following briefly addresses some of the areas where Ralph Stanton has made major contributions
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