检索结果-南通市图书馆

在线全文

学校读者我要写书评

暂无评论

民机机队航班指派与维修调度联合优化策略

计算机集成制造系统 2024年第1期30卷 205-216页

作者：丁雨童郭晋之邢雪琪郑美妹夏唐斌奚立峰上海交通大学机械与动力工程学院上海200240 中国商飞上海飞机客户服务公司运行支持技术研究所上海200241

针对机队维修调度定检模式的经济性不足,综合飞机个体维修需求和机队整体航班运营与维修资源共享,提出一种新的民机机队航班指派与维修调度联合优化策略。为耦合飞行路径与维修方案,将飞行路径中涵盖的维修机会作为交互关键,创新改进了... 详细信息

针对机队维修调度定检模式的经济性不足,综合飞机个体维修需求和机队整体航班运营与维修资源共享,提出一种新的民机机队航班指派与维修调度联合优化策略。为耦合飞行路径与维修方案,将飞行路径中涵盖的维修机会作为交互关键,创新改进了连接网络模型框架以将航班指派与维修调度统筹规划。全面考虑航班全覆盖与执飞连续性的运营约束、飞机适航性要求与维修资源承载限制的维修约束,基于网络结构建立了联合优化整数规划模型。设计了一种基于原始问题分解的两阶段求解算法,通过维修机会导向的航班指派优化与维修任务择优分配,高效输出联合调度方案。通过实例分析证明所提策略能够高效获得低成本调度方案,为航司维修调度优化提供指导。

关键词：航班指派维修调度航空网络建模启发式分解算法整数规划

Adaptive SPC monitoring scheme for DOE-based APC

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2008年第2期19卷 329-336页

作者： Ye Liang Pan Ershun xi lifeng Dept. of Industrial Engineering and Logistics School of Management Engineering Shanghai Jiaotong Univ. Shanghai 200240 P. R. China

Automatic process control (APC) based on design of experiment (DOE) is a cost-efficient approach for variation reduction. The process changes both in mean and variance owing to online parameter adjustment make it hard to apply traditional SPC charts in such DOE-based APC applied process. An adaptive SPC scheme is developed, which can better track the process transitions and achieve the possible SPC run cost reduction when the process is stable. The control law of SPC parameters is designed by fully utilizing the estimation properties of the process model instead of traditionally using the data collected from the production line. An example is provided to illustrate the proposed adaptive SPC design approach.

关键词： automatic process control statistical process control robust parameter design process transitions.

STATE SPACE MODELING OF DIMENSIONAL MACHINING ERRORS OF SERIAL-PARALLEL HYBRID MULTI-STAGE MACHINING SYSTEM

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2007年第5期20卷 64-67页

作者： xi lifeng DU Shichang School of Mechanical Engineering Shanghai Jiaotong University Shanghai 200030 China

The final product quality is determined by cumulation, coupling and propagation of product quality variations from all stations in multi-stage manufacturing systems （MMSs）. Modeling and control of variation propagation is essential to improve product quality. However, the current stream of variations （SOV） theory can only solve the problem that a single SOV affects the product quality. Due to the existence of multiple variation streams, limited research has been done on the quality control in serial-parallel hybrid multi-stage manufacturing systems （SPH-MMSs）. A state space model and its modeling strategies are developed to describe the multiple variation streams stack-up in an SPH-MMS. The SOV theory is extended to SPH-MMS. The dimensions of system model are reduced to the production-reality level, and the effect and feasibility of the model is validated by a machining case.

关键词： Multi-stage manufacturing system System model Product quality

CALCULUS ON CANTOR TRIADIC SET(Ⅱ)—EXCEPTIONAL SET

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics(A Journal of Chinese Universities) 1998年第2期13卷 231-240页

作者： xi lifeng Department of Mathematics Wuhan University Huhan

Abstract In this paper the derivative and its exceptional set according to the alternatively jumping function and self similar function respectively are discussed. And in the appendix, a proof of the statement 1.2(2) of “Calculus on Cantor triadic set (Ⅰ)_derivative” which is important to the discussion of exceptional set is given.

关键词： SET TRIADIC CANTOR EXCEPTIONAL CALCULUS

CALCULUS ON CANTOR TRIADIC SET (I)-DERIVATIVE

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics(A Journal of Chinese Universities) 1997年第4期12卷 483-492页

作者： xi lifeng Department of Mathematics Zhejiang University Hangzhou

For real valued functions defined on Cantor triadic set, a derivative with corresponding formula of Newton Leibniz’s type is given. In particular, for the self similar functions and alternately jumping functions defined in this paper, their derivative and exceptional sets are studied accurately by using ergodic theory on Σ 2 and Duffin Schaeffer’s theorem concerning metric diophantine approximation. In addition, Haar basis of L 2(Σ 2) is constructed and Haar expansion of standard self similar function is given.

关键词： Fractal derivative on Cantor set exceptional set ergodic theory Duffin Schaeffer’ s theorem

Quasi-Lipschitz equivalence of quasi Ahlfors-David regular sets

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2011年第12期54卷 2573-2582页

作者： WANG Qin xi lifeng School of Computer Science and Information Technology Zhejiang Wanli University Ningbo 315100 China Institute of Mathematics Zhejiang Wanli University Ningbo 315100 China

Suppose compact sets E and F are quasi uniformly disconnected and quasi Ahlfors-David *** paper proves that E and F are quasi-Lipschitz equivalent if and only if they have the same Hausdorff dimension.

关键词： fractal quasi-Lipschitz equivalence Ahlfors-David regularity

Dimension of Slices Through Fractals with Initial Cubic Pattern

在线全文

学校读者我要写书评

暂无评论

Chinese Annals of Mathematics,Series B 2017年第5期38卷 1145-1178页

作者： lifeng xi Wen WU Ying xiONG Department of Mathematics Ningbo UniversityNingbo 315211ZhejiangChina School of Mathematics South China University of TechnologyGuangzhou 510641China

In this paper, the Hausdorff dimension of the intersection of self-similar fractals in Euclidean space R^n generated from an initial cube pattern with an(n-m)-dimensional hyperplane V in a fixed direction is discussed. The authors give a sufficient condition which ensures that the Hausdorff dimensions of the slices of the fractal sets generated by "multirules" take the value in Marstrand's theorem, i.e., the dimension of the self-similar sets minus one. For the self-similar fractals generated with initial cube pattern, this sufficient condition also ensures that the projection measure μVis absolutely continuous with respect to the Lebesgue measure L^m. When μV《 L^m, the connection of the local dimension ofμVand the box dimension of slices is given.

关键词： Slice Self-similar set Dimension Fractal

Arithmetic progressions in self-similar sets

在线全文

学校读者我要写书评

暂无评论

Frontiers of Mathematics in China 2019年第5期14卷 957-966页

作者： lifeng xi Kan JIANG Qiyang PEI Department of Mathematics Ningbo UniversityNingbo 315211China

Given a sequence{bi}i=1^n and a ratio λ∈(0,1),let E=Ui=1^n(λE+bi)be a homogeneous self-similar *** this paper,we study the existence and maximal length of arithmetic progressions in *** main idea is from the multip... 详细信息

关键词： Self-similar sets arithmetic progression (AP) β-expansions

Sharp Lipschitz constant of bi-Lipschitz automorphism on Cantor set

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Mathematics 2009年第4期52卷 709-719页

作者： xiONG Ying WANG LiSha xi lifeng Department of Mathematics South China University of TechnologyGuangzhou 510641China Department of Mathematics Hubei UniversityWuhan 430062China Institute of Mathematics Zhejiang Wanli UniversityNingbo 315100China

Suppose C r = (r C r ) ∪ (r C r + 1 ? r) is a self-similar set with r ∈ (0, 1/2), and Aut(C r ) is the set of all bi-Lipschitz automorphisms on C r . This paper proves that there exists f* ∈ Aut(C r ) such that $$ blip(f*) = inf\{ blip(f) > 1:f \in Aut(C_r )\} = min\left[ {\frac{1} {r},\frac{{1 - 2r^3 - r^4 }} {{(1 - 2r)(1 + r + r^2 )}}} \right], $$ where $ lip(g) = sup_{x,y \in C_r ,x \ne y} \frac{{\left| {g(x) - g(y)} \right|}} {{\left| {x - y} \right|}} $ and blip(g) = max(lip(g), lip(g ?1)).

关键词： fractal bi-Lipschitz automorphism Cantor set 28A80