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381.
Faizal Karim Marco Ottavi Hamidreza Hashempour Vamsi Vankamamidi Konrad Walus André Ivanov Fabrizio Lombardi 《Journal of Electronic Testing》2009,25(1):55-66
This paper analyzes the effect of random phase shifts in the underlying clock signals on the operation of several basic Quantum-dot
Cellular Automata (QCA) building blocks. Such phase shifts can result from manufacturing variations or from uneven path lengths
in the clocking network. We perform numerical simulations of basic building blocks using two different simulation engines
available in the QCADesigner tool. We assume that the phase shifts are characterized by a Gaussian distribution with a mean
value of , where i is the clock number and a standard deviation, σ, which is varied in each simulation. Our results indicate that the sensitivity of building blocks to phase shifts depends
primarily on the layout while the reliability of all building blocks starts to drop once the standard deviation, σ exceeds 4°. A full adder was simulated to analyze the operation of a circuit featuring a combination of the building blocks
considered here. Results are consistent with expectations and demonstrate that the carry output of the full adder is better
able to withstand the phase shifts in the clocking network than the Sum output which features a larger combination of the simulated building blocks.
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Faizal KarimEmail: |
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P Lombardi C Fiorino GM Cattaneo R Calandrino 《Canadian Metallurgical Quarterly》1997,70(834):638-644
The results of an investigation of the accuracy of monitor unit (MU) calculation in clinical shaped beams are presented. Measured doses at the reference depth on the beam central axis (isocentre) or on a beam axis representative of the irradiated area (when the isocentre lies under a block or near the edges of the block's shadow) were compared with the expected doses when calculating MUs, by applying different methods normally used in clinical practice. Empirical (areas weighted, Wrede) and scatter summation (Clarkson) methods as well as a pencil-beam based algorithm were applied. 40 irregular fields (6 MV X-rays, CLinac, Varian 6/100), divided into six categories, were considered. Dose measurements were performed with a NE2571 ionization chamber in an acrylic 30 x 30 x 30 cm3 phantom. The depths in acrylic were converted into water-equivalent depths through a correction factor derived from TMR measurements. The method of dose measurements in acrylic was found to be sufficiently accurate for the purpose of this study by comparing expected and measured doses in open square and rectangular fields (mean deviation +0.2%, SD = 0.5%). Results show that all the considered methods are sufficiently reliable in calculating MUs in clinical situations. Mean deviations between measured and expected dose values are around 0 for all the methods; standard deviations range from 1% for the Wrede method to 0.75% for the pencil-beam method. The differences between expected and measured doses were within 1% for about 3/4 of the fields when calculating MUs with all the considered methods. Maximum deviations range from 1.6% (pencil-beam) to 3% (Wrede). Slight differences among the methods of MU calculation were revealed within the different categories of blocked fields analysed. The surprising agreement between measured and expected dose values obtained by using empirical methods (area weighted and Wrede) is probably due to the fact that the reference points were positioned in a "central" region of the unblocked areas. 相似文献
389.
Dondi Piercarlo Lombardi Luca Rocca Irene Malagodi Marco Licchelli Maurizio 《Multimedia Tools and Applications》2018,77(21):28309-28332
Multimedia Tools and Applications - The adoption of multimedia and multimodal applications inside museums and exhibitions is becoming a common practice. These installations proved to be... 相似文献
390.
We examine the diagnosis of processor array systems formed as two-dimensional arrays, with boundaries, and either four or eight neighbors for each interior processor. We employ a parallel test schedule. Neighboring processors test each other, and report the results. Our diagnostic objective is to find a fault-free processor or set of processors. The system may then be sequentially diagnosed by repairing those processors tested faulty according to the identified fault-free set, or a job may be run on the identified fault-free processors. We establish an upper bound on the maximum number of faults which can be sustained without invalidating the test results under worst case conditions. We give test schedules and diagnostic algorithms which meet the upper bound as far as the highest order term. We compare these near optimal diagnostic algorithms to alternative algorithms, both new and already in the literature, and against an upper bound ideal case algorithm, which is not necessarily practically realizable. For eight-way array systems with N processors, an ideal algorithm has diagnosability 3N/sup 2/3/-2N/sup 1/2/ plus lower-order terms. No algorithm exists which can exceed this. We give an algorithm which starts with tests on diagonally connected processors, and which achieves approximately this diagnosability. So the given algorithm is optimal to within the two most significant terms of the maximum diagnosability. Similarly, for four-way array systems with N processors, no algorithm can have diagnosability exceeding 3N/sup 2/3//2/sup 1/3/-2N/sup 1/2/ plus lower-order terms. And we give an algorithm which begins with tests arranged in a zigzag pattern, one consisting of pairing nodes for tests in two different directions in two consecutive test stages; this algorithm achieves diagnosability (3/2)(5/2)/sup 1/3/N/sup 2/3/-(5/4)N/sup 1/2/ plus lower-order terms, which is about 0.85 of the upper bound due to an ideal algorithm. 相似文献