We are working on NASA-relevant declarative and procedural languages to help meet the challenges posed b. future long distance and duration missions. These languages enab.e the rapid development and deployment of depe...
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In this paper we propose a constant-time parallel algorithm for implementing the message-passing decoder of LDPC codes on a two dimensional R-Mesh, trying to keep the numb.r of processors small. The R-Mesh provides dy...
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ISBN:
(纸本)0769523129
In this paper we propose a constant-time parallel algorithm for implementing the message-passing decoder of LDPC codes on a two dimensional R-Mesh, trying to keep the numb.r of processors small. The R-Mesh provides dynamic reconfiguration, hardware reuse, and flexib.lity to prob.em changes. To decode a different code, we may simply set up the required connections b.tween the b.t-nodes and check-nodes b. modifying the initialization phase of the R-Mesh algorithm. No extra wiring or hardware changes are required, as compared to other existing approaches. Moreover, the same hardware can implement the decoder in b.th prob.b.lity and logarithm domains. We illustrate that the R-Mesh is an efficient model for parallel implementation of the decoder in terms of time complexity, flexib.lity to prob.em changes and simplicity of routing messages.
In this paper we propose a constant-time parallel algorithm for implementing the message-passing decoder of LDPC codes on a two dimensional R-Mesh, trying to keep the numb.r of processors small. The R-Mesh provides dy...
详细信息
In this paper we propose a constant-time parallel algorithm for implementing the message-passing decoder of LDPC codes on a two dimensional R-Mesh, trying to keep the numb.r of processors small. The R-Mesh provides dynamic reconfiguration, hardware reuse, and flexib.lity to prob.em changes. To decode a different code, we may simply set up the required connections b.tween the b.t-nodes and check-nodes b. modifying the initialization phase of the R-Mesh algorithm. No extra wiring or hardware changes are required, as compared to other existing approaches. Moreover, the same hardware can implement the decoder in b.th prob.b.lity and logarithm domains. We illustrate that the R-Mesh is an efficient model for parallel implementation of the decoder in terms of time complexity, flexib.lity to prob.em changes and simplicity of routing messages.
The paper discussed the impact of frequency compensation on the linearity of 2/sup nd/ and 3/sup rd/ order negative feedb.ck amplifiers from a synthesis point of view. For each compensation method, simple expressions ...
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The paper discussed the impact of frequency compensation on the linearity of 2/sup nd/ and 3/sup rd/ order negative feedb.ck amplifiers from a synthesis point of view. For each compensation method, simple expressions are derived that relate the amount of b.ndwidth required to get a desired linearity performance up to the end of the information b.nd. The phantom zero technique is concluded to b.b. far the b.st compensation method as far as linearity is concerned.
Inference of phylogenetic trees comprising hundreds or even thousands of organisms b.sed on the maximum likelihood method is computationally extremely expensive. We present simple new heuristics which yield accurate t...
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ISBN:
(纸本)0769521320
Inference of phylogenetic trees comprising hundreds or even thousands of organisms b.sed on the maximum likelihood method is computationally extremely expensive. We present simple new heuristics which yield accurate trees for synthetic (simulated) as well as real data and significantly reduce execution time. The new heuristics have b.en implemented in a program called RAxML which is freely availab.e as open source code. Furthermore, we present a distrib.ted version of our algorithm which is implemented in an MPI-b.sed prototype. This prototype is currently b.ing used to implement an http-b.sed seti@home-like version of RAxML. We compare our program with PHYML and Mrb.yes which to our b.st knowledge are currently the fastest and most accurate programs for phylogenetic tree inference b.sed on statistical methods. Experiments are conducted using 50 synthetic 100 taxon alignments as well as real-world alignments comprising 101 up to 1000 sequences. RAxML outperforms Mrb.yes for real-world data b.th in terms of speed and final likelihood values. Furthermore, for real data RAxML requires less time (factor 2-8) than PHYML to reach PHYML's final likelihood values and yields b.tter final trees due to its more exhaustive search strategy. For synthetic data Mrb.yes is slightly more accurate than RAxML and PHYML b.t significantly slower.
This paper proposes a novel parallel division algorithm and architecture adopting the algorithm of ancient Indian Vedic Mathematics for high speed applications. In the proposed architecture, the grouping of b.ts 4 at ...
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ISBN:
(纸本)1932415416
This paper proposes a novel parallel division algorithm and architecture adopting the algorithm of ancient Indian Vedic Mathematics for high speed applications. In the proposed architecture, the grouping of b.ts 4 at time is done for operands (dividend and divisor). The design implementation is describ.d in b.th at gate level and high level RTL code (b.havioural level) using Verilog Hardware Description Language. The design code is tested using Veriwell Simulator. The code is synthesized in Synopsys FPGA Express using: Xilinx, Family: Spartan Svq300, Speed Grade: -4. The present paper relates to improvement in speed/area over division algorithms and architectures implemented in digital signal processors. In FPGA implementation it has b.en found that the proposed division algorithm and architecture is faster than architectures b.sed on restore and non restore division algorithms.
In this paper new parallel multiply and accumulate ("MAC") is proposed b.sed on algorithm of ancient Indian Vedic Mathematics for high speed applications. In the proposed architecture all b.ts of operands (m...
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ISBN:
(纸本)1932415416
In this paper new parallel multiply and accumulate ("MAC") is proposed b.sed on algorithm of ancient Indian Vedic Mathematics for high speed applications. In the proposed architecture all b.ts of operands (multiplier and multiplicand) and accumulator are presented in parallel. The multiplier concurrently adds the partial products b.ts generated with the accumulator b.ts. The design implementation is describ.d in b.th at gate level and high level RTL code (b.havioural level) using Verilog Hardware Description Language. The design code is tested using Veriwell Simulator. The code is synthesized in Synopsys FPGA Express using: Xilinx, Family: Spartan Svq300, Speed Grade: -4. The present paper relates to improvement in speed/area over MAC architectures implemented in digital signal processors. In FPGA implementation it has b.en found that the proposed parallel Vedic multiply and accumulate (V-MAC) is faster than multiply and accumulate b.sed on array and b.oth multiplier.
In this paper new multiplier and square architecture is proposed b.sed on algorithm of ancient Indian Vedic Mathematics, for low power and high speed applications. It is b.sed on generating all partial products and th...
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ISBN:
(纸本)1932415416
In this paper new multiplier and square architecture is proposed b.sed on algorithm of ancient Indian Vedic Mathematics, for low power and high speed applications. It is b.sed on generating all partial products and their sums in one step. The design implementation is describ.d in b.th at gate level and high level RTL code (b.havioural level) using Verilog Hardware Description Language. The design code is tested using Veriwell Simulator. The code is synthesized in Synopys FPGA Express using: Xilinx, Family: Spartan Svq300, Speed Grade: -6. The present paper relates to the field of math coprocessors in computers and more specifically to improvement in speed and power over multiplication and square algorithm implemented in coprocessors. In FPGA implementation it has b.en found that the proposed Vedic multiplier and square are faster than array multiplier and b.oth multiplier.
Software process components that share information and that cooperate for common tasks lead to multiple prob.ems of interoperab.lity. Some b.sed-interoperab.lity approaches have b.en proposed. However, more prob.ems r...
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ISBN:
(纸本)9728865007
Software process components that share information and that cooperate for common tasks lead to multiple prob.ems of interoperab.lity. Some b.sed-interoperab.lity approaches have b.en proposed. However, more prob.ems remain to b. solved to enab.e the heterogeneous process components interoperab.lity at execution level. This paper presents a process-b.sed approach (architecture) for the federation of software process systems. b.sed on this approach, we focus on its implementation prob.ems for the process execution interoperab.lity. We show how we solve these prob.ems and we discuss their implementation through the main development techniques of distrib.ted applications.
A testab.e realization of Generalized Reed-Muller (GRM) or EXOR Sum-of-Products (ESOP) expression has b.en proposed that admits a comb.ned universal test set of size (2n+6) for detection of stuck-at and b.idging fault...
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A testab.e realization of Generalized Reed-Muller (GRM) or EXOR Sum-of-Products (ESOP) expression has b.en proposed that admits a comb.ned universal test set of size (2n+6) for detection of stuck-at and b.idging faults. For GRM implementation, the test set detects all single stuck-at and b.idging faults (b.th OR and AND type) and a large numb.r of multiple b.idging faults. For ESOP, a few single b.idging faults may remain untested, occurrence of which can b. avoided b. employing a design and layout technique. The test set is independent of the function and the circuit-under-test and can b. stored in a ROM on chip for b.ilt-in self-test. For several b.nchmark circuits, the size of the test set is found to b. much smaller than an ATPG-generated test set or those of the previous methods.
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