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The trace inverse functions Tr(λx~(-1)) over the finite field F_(2~n) are a class of very important Boolean functions and are used in many stream ciphers such as SFINKS,RAKAPOSHI,the simple counter stream cipher(SCSC) presented by Si W and Ding C(2012),etc.In order to evaluate the security of those ciphers in resistance to(fast) algebraic attacks,the authors need to characterize algebraic properties of Tr(λx~(-1)).However,currently only some bounds on algebraic immunity of Tr(λx~(-1)) are given in the public literature,for example,the NGG upper bound and the Bayev lower bound,etc.This paper gives the exact value of the algebraic immunity of Tr(λx~(-1)) over F_(2~n),that is,AI(Tr(λx~(-1))) =[2n~(1/2)]- 2,where n ≥ 2,A ∈ F_(2~n) and λ≠ 0,which shows that Dalai's conjecture on the algebraic immunity of Tr(λx~(-1)) is correct.What is more,the authors demonstrate some weak properties of Tr(λx~(-1)) against fast algebraic attacks.  相似文献   

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This paper deduces the structure of LCD negacyclic codes over the finite field Fq, where q is an odd prime power. Based on the study of q-cyclotomic cosets modulo 2 n, the authors obtain the parameters of LCD negacyclic codes of lengths n =(q+1)/2,(q~m-1)/2(q-1)and q~(t·2~τ)-1/2(q~t +1), respectively. And many optimal codes are given. Moreover, the authors research two special classes of MDS LCD negacyclic codes of length n |(q-1)/2 and n |(q+1)2, respectively.  相似文献   

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This paper is devoted to the construction of one-Lee weight codes and two-Lee weight codes over F p + vF p (v 2 = v) with type \({p^{2{k_1}}}{p^{{k_2}}}{p^{{k_3}}}\) based on two different distance-preserving Gray maps from ((F p + vF p ) n , Lee weight) to (F p 2n , Hamming weight), where p is a prime. Moreover, the authors prove that the obtained two-Lee weight codes are projective only when p = 2.  相似文献   

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This paper firstly gives some necessary conditions on one-Gray weight linear codes. And then we use these results to construct several classes of one-Gray weight linear codes over ?4+u?4(u 2 = u) with type \({16^{{k_1}}}{8^{{k_2}}}{8^{{k_3}}}{4^{{k_4}}}{4^{{k_5}}}{4^{{k_6}}}{2^{{k_7}}}{2^{{k_8}}}\) based on a distance-preserving Gray map from (?4 + u?4) n to ? 4 2n . Secondly, the authors use the similar approach to do works on two-Gray (projective) weight linear codes. Finally, some examples are given to illustrate the construction methods.  相似文献   

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This paper considers two parallel machine scheduling problems,where the objectives of both problems are to minimize the makespan,and the jobs arrive over time,on two uniform machines with speeds 1 and s(s≥1),and on m identical machines,respectively.For the first problem,the authors show that the on-line LPT algorithm has a competitive ratio of(1 +5~(1/2))/2≈1.6180 and the bound is tight.Furthermore,the authors prove that the on-line LPT algorithm has the best possible competitive ratio if s≥1.8020.For the second problem,the authors present a lower bound of(15-(17)~(1/2))/8≈1.3596 on the competitive ratio of any deterministic on-line algorithm.This improves a previous result of 1.3473.  相似文献   

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This paper presents a new algorithm for computing the extended Hensel construction(EHC) of multivariate polynomials in main variable x and sub-variables u_1, u_2, ···, u_m over a number field K. This algorithm first constructs a set by using the resultant of two initial coprime factors w.r.t. x, and then obtains the Hensel factors by comparing the coefficients of x~i on both sides of an equation. Since the Hensel factors are polynomials of the main variable with coefficients in fraction field K(u_1, u_2, ···, u_m), the computation cost of handling rational functions can be high. Therefore,the authors use a method which multiplies resultant and removes the denominators of the rational functions. Unlike previously-developed algorithms that use interpolation functions or Gr?bner basis, the algorithm relies little on polynomial division, and avoids multiplying by different factors when removing the denominators of Hensel factors. All algorithms are implemented using Magma, a computational algebra system and experiments indicate that our algorithm is more efficient.  相似文献   

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In this paper, a family of non-monomial permutations over the finite field \({F_{{2^n}}}\) with differential uniformity at most 6 is proposed, where n is a positive integer. The algebraic degree of these functions is also determined.  相似文献   

12.
This study provides a framework of target costing to extend its original scope when the underlying distribution is non-normal. The new specification limits can be derived by listening to the market price from Taguchi loss function. Later, the new specification limits can be linked through the non-normality-based C^^pk value along with non-normality-based X^^-Rcontrol charts to derive goal control limits. Moreover, an example is provided to illustrate the usefulness of the proposed framework of target costing by relentlessly reducing cost and improving product quality to gain competitiveness in the marketplace.  相似文献   

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This paper is devoted to the study of semi-bent functions with several parameters flexible on the finite field F2n.Boolean functions defined on F2n of the form f(r)ab(x) =Trn1(axr(2m-1))+Tr41(bx(2n-1)/5) and the form g(rs)abcd(x)=Trn1(axr(2m-1))+Tr41(bx(2n-1)/5)+Trn1(cx(2m-1)1/2+1)+Trn1(dx(2m-1)s+1) where n = 2m,m = 2(mod 4),a,c ∈ F2n,and b ∈ F(16),d ∈ F2,are investigated in constructing new classes of semi-bent functions.Some characteristic sums such as Kloosterman sums and Weil sums are employed to determine whether the above functions are semi-bent or not.  相似文献   

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This paper considers the Rosenau equation with a moving control?t u + ?_t?_x~4 u + ?_xu + u?x u = a(x + ct)h(x, t), c = 0, x ∈ T = R/(2πZ), t 0.The authors prove that the Rosenau equation with a moving control is locally exact controllable in Hs(T) with s ≥ 0 and globally exponential stable in H~s(T) with s ≥ 2. The two results nontrivially extend the work of(Rosier L and Zhang B Y, 2013) from the BBM equation to the Rosenau equation.  相似文献   

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Front end innovation (FEI) represents the first building blocks of product development, but is often regarded as a weak link in innovation literature. Various theorists emphasize that a firm??s innovation can benefit substantially by improving the front end of innovation process (Reinertsen, Res Technol Manag 42:23?C31, 1999; Stevens and Burly, Res Technol Manag 46(2):16?C25, 2003; Verworn et al., R&D Manag 38(1):1?C19, 2008) and that innovation strategies play a central role in optimization of innovation (Clark and Wheelwright, Leading product development, Free Press, New York, 1995; Cottam et al., Eur J Innov Manag 4:88?C94, 2001; Morgan and Berthon, J Manag Stud 45(8):1329?C1353, 2008). Innovation strategies are suggested in literature (e.g. Page, J Prod Innov Manag 10:273?C287, 1993; Oke, J Change Manag 2(3):272?C281, 2002; Adams et al., Int J Manag Rev 8(1):21?C47, 2006; Igartua et al., Res Technol Manag May?CJune:41?C52, 2010) as a facilitator of innovation and may therefore also be targeted at FEI support. The pharmaceutical industry has experienced a worldwide decline in the number of applications for new molecular entities to regulatory agencies since 1997. Therefore high pressures are put on pharmaceutical research and FEI to produce more valid candidates and faster for drug development. This paper explores how pharmaceutical FEI can be actively supported through the development and implementation of an innovation strategy. The empirical field and applied methodology is an action oriented longitudinal case study of a Danish pharmaceutical company. The findings and key learnings from the study are presented as propositions of how innovation strategies can be applied to actively facilitate FEI and with measurable results.  相似文献   

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The authors establish weighted L2-estimates of solutions for the damped wave equations with variable coefficients u tt ? divA(x)?u+au t = 0 in ? n under the assumption a(x) ≥ a0[1+ρ(x)]?l, where a0 > 0, l < 1, ρ(x) is the distance function of the metric g = A?1(x) on ? n . The authors show that these weighted L2-estimates are closely related to the geometrical properties of the metric g = A?1(x).  相似文献   

17.
This paper studies variational discretization for the optimal control problem governed by parabolic equations with control constraints.First of all,the authors derive a priori error estimates where |||u-U(h|||L∞(J;L2(Ω))=O(h2+k).It is much better than a priori error estimates of standard finite element and backward Euler method where |||μ-Uh|||(L∞(J;L2(Ω))=O(h+ k).Secondly,the authors obtain a posteriori error estimates of residual type.Finally,the authors present some numerical algorithms for the optimal control problem and do some numerical experiments to illustrate their theoretical results.  相似文献   

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In this paper, the authors consider an on-line scheduling problem of m (m ≥ 3) identical machines with common maintenance time interval and nonresumable availability. For the case that the length of maintenance time interval is larger than the largest processing time of jobs, the authors prove that any on-line algorithm has not a constant competitive ratio. For the case that the length of maintenance time interval is less than or equal to the largest processing time of jobs, the authors prove a lower bound of 3 on the competitive ratio. The authors give an on-line algorithm with competitive ratio $4 - \tfrac{1} {m} $ . In particular, for the case of m = 3, the authors prove the competitive ratio of the on-line algorithm is $\tfrac{{10}} {3} $ .  相似文献   

19.
Systems Thinking and Higher Education: The Vanguard Method   总被引:1,自引:1,他引:0  
Reforms to the higher education sector in the UK are only increasing competitive pressures between institutions. Universities are therefore looking to gain competitive advantage over their rivals both in terms of student experience and through administrative efficiency. This paper will present an alternative view of how to transform the way that the higher education system delivers service to students in an environment where ‘student choice’ will be viewed as of paramount importance. The paper will argue that the prevailing ‘command and control’ (Seddon 2003) management logic, which can be found at work throughout both the public and private sectors, is the primary cause of inferior, expensive service. As an alternative, this paper will explore the benefits of working in a systems thinking way, whilst comparing and contrasting this with the flawed thinking which currently prevails. The Vanguard Method (Seddon 2008) is one particular form of systems thinking which has been developed for use in service organisations (Jackson et al. 2008) and which has been applied to many public sector organisations (ODPM 2005; Middleton 2010; Zokaei et al. 2010). Using a case study methodology (Yin 2009), this paper will address what has been learnt by applying the Vanguard Method in an HEI environment for the first time.  相似文献   

20.
This paper considers the semiparametric regression model j/j= Xif3+g(U)+Vi(1 < i < n), where(xi,ti) are known design points,/3 is an unknown slope parameter,g(·) is an unknown function, the correlated errors Vi=∑j=-∞cjei-jwith∑j=-∞|cj|<∞,and ei negatively associated random variables.Under appropriate conditions,the authors study the asymptotic normality for wavelet estimators ofβand g(·).A simulation study is undertaken to investigate finite sample behavior of the estimators.  相似文献   

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