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采用M5'模型树和测量数据识别抽汽式机组汽耗量特性 被引量:7
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作者 章坚民 刘登涛 +1 位作者 吴光中 张云雷 《中国电机工程学报》 EI CSCD 北大核心 2011年第23期21-26,共6页
汽轮机组特性随着机组老化而变化,传统上采用定期现场实测,需停机和采用专门的设备与系统,费用很高,因此基于现有自动化系统历史测量数据的特性曲线识别方法十分必要。一般汽轮机组汽耗量特性具有非凸和非连续等特点,常规的多元线性回... 汽轮机组特性随着机组老化而变化,传统上采用定期现场实测,需停机和采用专门的设备与系统,费用很高,因此基于现有自动化系统历史测量数据的特性曲线识别方法十分必要。一般汽轮机组汽耗量特性具有非凸和非连续等特点,常规的多元线性回归拟合不能适应。M5’模型树算法是一种多输入单输出系统的分段线性化的数据挖掘算法。提出采用M5’模型树的抽汽式机组汽耗量特性模型和其模型结构及参数识别算法,用于滚动利用最新的电厂测量历史数据获取最新的汽耗量特性。该方法简单、有效,逼近能力强,自动化程度高,在处理非凸形和非连续性的特性方程具有优势。通过多个热电厂的实时数据进行验证,具有很高的预测精度,效果优于多元线性回归拟合方程。 展开更多
关键词 抽汽式机组 汽耗量特性 M5’模型树 凸性函数 非连续性函数 多元线性回归模型
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A Construction of 1-Resilient Boolean Functions with Good Cryptographic Properties 被引量:1
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作者 SHAN Jinyong HU Lei +1 位作者 ZENG Xiangyong LI Chunlei 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2018年第4期1042-1064,共23页
This paper proposes a general method to construct 1-resilient Boolean functions by modifying the Tu-Deng and Tang-Carlet-Tang functions. Cryptographic properties such as algebraic degree, nonlinearity and algebraic im... This paper proposes a general method to construct 1-resilient Boolean functions by modifying the Tu-Deng and Tang-Carlet-Tang functions. Cryptographic properties such as algebraic degree, nonlinearity and algebraic immunity are also considered. A sufficient condition of the modified func- tions with optimal algebraic degree in terms of the Siegenthaler bound is proposed. The authors obtain a lower bound on the nonlinearity of the Tang-Carlet-Tang functions, which is slightly better than the known result. If the authors do not break the "continuity" of the support and zero sets, the functions constructed in this paper have suboptimal algebraic immunity. Finally, four specific classes of 1-resilient Boolean functions constructed from this construction and with the mentioned good cryptographic properties are proposed. Experimental results show that there are many 1-resilient Boolean functions have higher nonlinearities than known l-resilient functions modified by Tu-Deng and Tang- Carlet-Tang functions. 展开更多
关键词 Algebraic immunity Boolean functions correlation immunity NONLINEARITY resilient
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A SIMPLE SMOOTH EXACT PENALTY FUNCTION FOR SMOOTH OPTIMIZATION PROBLEM 被引量:3
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作者 Shujun LIAN Liansheng ZHANG 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2012年第3期521-528,共8页
For smooth optimization problem with equMity constraints, new continuously differentiable penalty function is derived. It is proved exact in the sense that local optimizers of a nonlinear program are precisely the opt... For smooth optimization problem with equMity constraints, new continuously differentiable penalty function is derived. It is proved exact in the sense that local optimizers of a nonlinear program are precisely the optimizers of the associated penalty function under some nondegeneracy assumption. It is simple in the sense that the penalty function only includes the objective function and constrained functions, and it doesn't include their gradients. This is achieved by augmenting the dimension of the program by a variable that controls the weight of the penalty terms. 展开更多
关键词 Constrained optimization exact penalty function smooth penalty function.
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OSCILLATION OF A FORCED SECOND ORDER NONLINEAR EQUATION
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作者 KONGQINGKAI ZHANGBINGGEN 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 1994年第1期59-68,共10页
This paper gives several criteria on the oscillatory behavior of solutions of the forced secondorder equation x″+ a(t)i(x) = g(t), where g(t) is oscillatory) by using a geometric idea. Asspecial cases these results i... This paper gives several criteria on the oscillatory behavior of solutions of the forced secondorder equation x″+ a(t)i(x) = g(t), where g(t) is oscillatory) by using a geometric idea. Asspecial cases these results include and improve some recent results, given by J. S. Wong. Thecriteria also solve the problem posed by H. Onose in Mathematical Reviews, 1986. 展开更多
关键词 OSCILLATION FORCED Nonlinear Differential equations.
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Existence and Global Asymptotic Behavior of Positive Solutions for Sublinear and Superlinear Fractional Boundary Value Problems
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作者 Imed BACHAR Habib MAAGLI +1 位作者 Faten TOUMI Zagharide ZINE EL ABIDINE 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2016年第1期1-28,共28页
In this paper, the authors aim at proving two existence results of fractional differential boundary value problems of the form (Pa,bα){D^au(x)+f(x,u(x))=0,x∈(0,1),u(0)=u(1)=0,D^a-3u(0)=a,u^(1)=-6w... In this paper, the authors aim at proving two existence results of fractional differential boundary value problems of the form (Pa,bα){D^au(x)+f(x,u(x))=0,x∈(0,1),u(0)=u(1)=0,D^a-3u(0)=a,u^(1)=-6where 3 ≤ a 〈 4, D^ is the standard Riemann-Liouville fractional derivative and a, b are nonnegative constants. First the authors suppose that f(x, t) = -p(x)t^σ, with cr ~ (-1, 1) and p being a nonnegative continuous function that may be singular at x - 0 or x - 1 and satisfies some conditions related to the Karamata regular variation theory. Combining sharp estimates on some potential functions and the Sch^uder fixed point theorem, the authors prove the existence of a unique positive continuous solution to problem (P0,0). Global estimates on such a solution are also obtained. To state the second existence result, the authors assume that a, b are nonnegative constants such that a + b 〉 0 and f(x, t) -= tφ(x, t), with φ(x, t) being a nonnegative continuous function in (0, 1) × [0, ∞) that is required to satisfy some suitable integrability condition. Using estimates on the Green's function and a perturbation argument, the authors prove the existence and uniqueness of a positive continuous solution u to problem (Pa,b), which behaves like the unique solution of the homogeneous problem corresponding the existence results. to (Pa,b). Some examples are given to illustrate the existence results., 展开更多
关键词 Fractional differential equation Positive solution Fractional Green's function Karamata function Perturbation arguments Sch/iuder fixad point theorem
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Existence and concentration behavior of sign-changing solutions for quasilinear Schr?dinger equations equations
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作者 DENG YinBin SHUAI Wei 《Science China Mathematics》 SCIE CSCD 2016年第6期1095-1112,共18页
We consider the quasilinear Schrdinger equations of the form-ε~2?u + V(x)u- ε~2?(u2)u = g(u), x ∈ R^N,where ε 〉 0 is a small parameter, the nonlinearity g(u) ∈ C^1(R) is an odd function with subcrit... We consider the quasilinear Schrdinger equations of the form-ε~2?u + V(x)u- ε~2?(u2)u = g(u), x ∈ R^N,where ε 〉 0 is a small parameter, the nonlinearity g(u) ∈ C^1(R) is an odd function with subcritical growth and V(x) is a positive Hlder continuous function which is bounded from below, away from zero, and infΛV(x) 0 such that for all ε∈(0, ε0],the above mentioned problem possesses a sign-changing solution uε which exhibits concentration profile around the local minimum point of V(x) as ε→ 0~+. 展开更多
关键词 sign-changing solution quasilinear Schr6dinger equations concentration profile
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