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The minimum number of NOT gates in a Boolean circuit computing a Boolean function f is called the inversion complexity of f. In 1958, Markov determined the inversion complexity of every Boolean function and, in particular, proved that log2(n+1) NOT gates are sufficient to compute any Boolean function on n variables. In this paper, we consider circuits computing non-deterministically and determine the inversion complexity of every Boolean function. In particular, we prove that one NOT gate is sufficient to compute any Boolean function in non-deterministic circuits if we can use an arbitrary number of guess inputs. 相似文献
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A theorem of Markov shows the necessary and sufficient number of negations for computing an arbitrary collection of Boolean functions. In this paper, we consider a class of bounded-depth circuits, in which each gate computes an arbitrary monotone Boolean function or its negation. We show tight bounds on the number of negations for computing an arbitrary collection of Boolean functions when such a class of circuits is under consideration. 相似文献
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Debajyoti Bera 《Information Processing Letters》2011,111(15):723-726
Quantum circuits, which are shallow, limited in the number of gates and additional workspace qubits, are popular for quantum computation because they form the simplest possible model similar to the classical model of a network of Boolean gates and capable of performing non-trivial computation. We give a new lower bound technique for such circuits and use it to give another proof that deterministic computation of the parity function cannot be performed by such circuits. 相似文献
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Michal Koucký 《Theory of Computing Systems》2009,45(4):865-879
We survey the current state of knowledge on the circuit complexity of regular languages and we prove that regular languages
that are in AC0 and ACC0 are all computable by almost linear size circuits, extending the result of Chandra et al. (J. Comput. Syst. Sci. 30:222–234,
1985). As a consequence we obtain that in order to separate ACC0 from NC1 it suffices to prove for some ε>0 an Ω(n
1+ε
) lower bound on the size of ACC0 circuits computing certain NC1-complete functions.
Partially supported by grant GA ČR 201/07/P276, project No. 1M0021620808 of MŠMT ČR and Institutional Research Plan No. AV0Z10190503. 相似文献
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Andreas Jakoby Rüdiger Reischuk Christian Schindelhauer 《Information and Computation》1999,150(2):187
In contrast to machine models like Turing machines or random access machines, circuits are a static computational model. The internal information flow of a computation is fixed in advance, independent of the actual input. Therefore, size and depth are natural and simple measures for circuits and provide a worst-case analysis. We consider a new model in which an internal gate is evaluated as soon as its result has been determined by a partial assignment of its inputs. This way, a dynamic notion of delay is obtained which gives rise to an average case measure for the time complexity of circuits. In a previous paper we have obtained tight upper and lower bounds for the average case complexity of several basic Boolean functions. This paper examines the asymptotic average case complexity for the set of alln-ary Boolean functions. In contrast to worst case analysis a simple counting argument does not work. We prove that with respect to the uniform probability distribution almost all Boolean functions require at leastn−log n−log log nexpected time. On the other hand, there is a significantly large subset of functions that can be computed with a constant average delay. Finally, for an arbitrary Boolean function we compare its worst case and average case complexity. It is shown that for each function that requires circuit depthd, i.e. of worst-case complexityd, the expected time complexity will be at leastd−log n−log dwith respect to an explicitly defined probability distribution. In addition, a nontrivial upper bound on the complexity of such a distribution will be obtained. 相似文献
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Dixon resultant is a fundamental tool of elimination theory in the study and practice of algebraic geometry. It has provided the efficient and practical solutions to some benchmark problems in a variety of application domains, such as automated reasoning, automatic control, and solid modelling. The major task of solutions is to construct the Dixon resultant matrix, the entries of which are more complicated than the entries of other resultant matrices. An existing extended recurrence formula can construct the Dixon resultant matrix fast. In this paper, we present a detailed analysis of the computational complexity of the recurrence formula for the general multivariate setting. Parallel computation can be applied to speed up the recursive procedure. Furthermore, we also generalize the computational complexity of three bivariate polynomials to the general multivariate case by using the construction of standard Dixon resultant matrix. Some experimental results are demonstrated by a range of nontrivial examples. 相似文献
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We examine the computational power of modular counting, where the modulus m is not a prime power, in the setting of polynomials in Boolean variables over Z
m
. In particular, we say that a polynomial P weakly represents a Boolean function f (both have n variables) if for any inputs x and y in {0,1}n, we have whenever . Barrington et al. (1994) investigated the minimal degree of a polynomial representing the OR function in this way, proving an upper bound of
O(n
1/
r
) (where r is the number of distinct primes dividing m) and a lower bound of . Here, we show a lower bound of when m is a product of two primes and in general. While many lower bounds are known for a much stronger form of representation of a function by a polynomial (Barrington
et al. 1994, Tsai 1996), very little is known using this liberal (and, we argue, more natural) definition. While the degree is known
to be for the generalized inner product because of its high communication complexity (Grolmusz 1995), our bound is the best known
for any function of low communication complexity and any modulus not a prime power.
received 29 September 1994 相似文献
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摘要:随着手机的普及、电动汽车和无线电技术的不断发展,电子产品也越来越丰富。对各种电池的充电速度和工作时间提出越来越高的要求。由于目前电池的电量工作时间较短、快速充电、远距离充电等问题不能解决,从而给人们的生活带来了极大的不便,特别限制了电动汽车工业的发展。所以针对电池的充电问题,本文设计了一款电磁谐振式无线充电器。该充电器采用STM32超低功耗单片机作为无线充电电路的主控制器,通过对发射信号频率的控制,使处于异地的输出电路工作在谐振状态,实现最大功率无线传送,接收端线圈输出再经过整流、稳压、滤波后输出+5V电压,最终经过智能控制电路给便携式设备中的锂电池充电。并通过指示灯显示电池是否正在充电、充满、电池反接和电源欠压等状态。该设计的充电设备具有使用灵活、方便、工作可靠,电能利用率高,无线充电距离远等特点,同时具有过压、过流保护,具有广泛的应用价值。 相似文献
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图像相关复杂度的研究领域很广泛,除了计算机科学领域,还延伸到医学、认知心理学等研究领域。在以上应用领域,与图像相关的复杂度的定义有很多,包括图像复杂度、视觉复杂度、场景复杂度,其中图像复杂度又可以进一步细分为颜色复杂度、纹理复杂度和形状复杂度。文中对以上这些复杂度的应用、定义和计算方法进行了归纳总结,并依据组成论中相关复杂度的定义,提出了一种研究图像复杂度的思路,即从图像组成元素的角度来研究图像复杂度。这种图像复杂度的定义只与图像本身所包含的元素、内容有关系,与图像处理任务和算法无关。同时,这种图像复杂度的定义符合一般意义下人对图像复杂性的感受和理解。图像元素可以分为颜色、形状、纹理三大类,它们又可以进一步用一些特征来表示。根据组成论,文中给出了定义这3种特征的广义集的方法。后续研究将进一步给出图像复杂度的计算算法,并通过与人工实验的相关性分析来验证计算结果是否与人的感受相一致。 相似文献
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本文首先分析了基于相移SPWM技术的并联逆变器的环流特性,提出了耦台均流电抗器的设计方法。最后,采用DSP构建数字控制系统,并在两台5KVA的电压型逆变器上进行了并联实验,实验结果验证了其正确性和有效性。 相似文献
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With the prevalent use of visual interfaces and the increasing demand to display more information, information complexity in human–computer interfaces becomes a major concern for designers. Complex interfaces may adversely affect the effectiveness, efficiency, and even the operational safety of a system. Previously, two questionnaires were developed by researchers at the Federal Aviation Administration to evaluate information complexity of air traffic control displays. This study adapted the questionnaires for commercial visual interfaces and validated them with two types of tasks on three travel websites. The questionnaire measures the information complexity of a visual display based on perceptual, cognitive, and action complexity in terms of three complexity factors: quantity, variety, and relation. The result demonstrates that the questionnaire that uses multiple items for measuring complexity construct has good reliability, validity, and sensitivity. Information complexity is also found to be negatively correlated with usability and positively correlated with mental workload. The contribution of the study includes validating the theoretical framework for the information complexity concept through the use of questionnaires and providing a practical tool for designers to measure information complexity of the visual display for iterative improvement. © 2011 Wiley Periodicals, Inc. 相似文献
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We consider hypotheses about nondeterministic computation that have been studied in different contexts and shown to have interesting
consequences:
We show that the NP-machine hypothesis is implied by each of the first two. Previously, no relationships were known among
these three hypotheses. Moreover, we unify previous work by showing that several derandomizations and circuit-size lower bounds
that are known to follow from the first two hypotheses also follow from the NP-machine hypothesis. In particular, the NP-machine
hypothesis becomes the weakest known uniform hardness hypothesis that derandomizes AM. We also consider UP versions of the
above hypotheses as well as related immunity and scaled dimension hypotheses.
相似文献
• | The measure hypothesis: NP does not have p-measure 0. |
• | The pseudo-NP hypothesis: there is an NP language that can be distinguished from any DTIME language by an NP refuter. |
• | The NP-machine hypothesis: there is an NP machine accepting 0* for which no -time machine can find infinitely many accepting computations. |
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A. N. Alekseichuck 《Cybernetics and Systems Analysis》2000,36(3):468-471
Relationships for the maximum of a minimal number of summands among all canonical polarized polynomials of a Boolean function
are obtained.
Translated from Kibernetika i Sistemnyi Analiz, No. 3, pp. 179–183, May–June, 2000. 相似文献