A New Technique for Ill-Conditioned Linear Systems

The technique we propose for solving ill-conditioned linear systems consists of two steps. First we compute the regularized solution on some values of the regularization parameter . Then we use these solutions either to extrapolate at =0 or to estimate the regularized solution with determined by the generalized cross validation or by the L-curve method.     

A Hierarchical Model for Control of Flexible Manufacturing Systems

Flexible Manufacturing Systems (FMSs) are usually composed of general purpose machines with automatic tool changing capability and integrated material handling. The complexity of FMSs requires sophisticated control. In this paper we present a four-level control hierarchy and outline computationally feasible control algorithms for each level. The top level is concerned with the choice of part types and volumes to be assigned to the FMS over the next several months. The second level plans daily or shift production. Production levels are set and tools are allocated to machines so as to minimize holding and shortage costs. Various FMS environments are presented. The third level determines process routes for each part type in order to minimize material handling. Additional tools are loaded on machines when possible to maximize alternate routeing. Routes are then assigned to parts to minimize workload assignment, and these are used by level four for actual routeing, sequencing and material handling path control. The level three model is formulated as a linear program, and heuristics are used for level four. An example is provided to illustrate the completeness of the decision hierarchy and the relationships between levels.     

过度投资与其制约因素的实证分析——以制造业上市公司为例

经理的机会主义引发企业过度投资行为。西方学者通过考察投资与现金流相关性,研究企业过度投资问题并找到相应经验证据。本文利用上市公司(2005会计年度)数据,研究制造业上市公司是否存在过度投资行为以及相关制约机制是否有效。结果表明:我国上市公司存在过度投资行为;经理持股、举借债务、大股东性质、现金股利是过度投资行为的有效制约机制;公司治理机制中的独立董事并未发挥作用。     

Couette-Taylor流三模系统的混沌行为及其仿真

研究了旋流式Couette-Taylor流三模态类Lorenz系统的动力学行为及其数值仿真问题.给出了此系统平衡点存在的条件,证明了其吸引子的存在性,给出了吸引子的Hausdorff维数上界的估计,数值模拟了系统分歧和混沌等的动力学行为发生的全过程,基于分岔图与最大Lyapunov指数谱和庞加莱截面以及功率谱和返回映射等仿真结果揭示了此系统混沌行为的普适特征.     

Toeplitz Preconditioners for Toeplitz Systems with Nonnegative Generating Functions

The preconditioned conjugate gradient method is employed tosolve Toeplitz systems T_nx = b where the generating functionsof the n-by-n Toeplitz matrices T_n are continuous nonnegativeperiodic functions defined in [–,]. The preconditionedC_n are band Toeplitz matrices with band-widths independent ofn. We prove that the spectra of C_n^-1T_n are uniformly boundedby constants independent of n. In particular, we show that thesolutions of T_nx = b can be obtained in O(nlogn) operations.     

Knapsack-based Algorithms for Designing Cellular Manufacturing Systems

In this paper, we use a 0–1 linear programming model for the machine assignment problem in cellular manufacturing. The formulated machine assignment problem considers many manufacturing factors such as machine utilization cost, cost of intercellular moves, part demand, and operating time capacity. The problem is shown to be NP-complete. Two designing algorithms are proposed to exploit the problem structure of the knapsack problem. Computational experience of the two algorithms is also reported.     

Soft Systems Models for Knowledge Elicitation and Representation

The paper contends that the conceptual modes used in Soft Systems Methodology have an unusual logical status. This enables them to be rendered in modal logic and used as a framework for knowledge elicitation and for the design of knowledge-based systems with learning capability.     

A Review of Process Optimization for Additive Manufacturing Based on Machine Learning

Additive manufacturing(AM), also known as 3D printing, has emerged as a groundbreaking technology that has transformed the manufacturing industry. Its ability to produce intricate and customized parts with remarkable speed and reduced material waste has revolutionized traditional manufacturing approaches. However, the AM process itself is a complex and multifaceted undertaking, with various parameters that can significantly influence the quality and efficiency of the printed parts. To address th...     

知识创造行为与组织惯例的演化博弈及其仿真研究

以演化博弈模型为主要理论工具,在对知识创造行为与组织惯例关系予以描述的基础上,构建知识创造行为与组织惯例的演化博弈模型。通过求解复制动态方程,分析不同条件下知识创造行为与组织惯例分别达到演化稳定均衡的策略。研究结果表明:知识创造行为与组织惯例的匹配属于动态、重复博弈过程,参与博弈的预期收益、激励成本、转换成本直接决定演化稳定策略且影响个体对知识创造行为与组织惯例的选择,知识创造行为则倾向以承袭为主的保守策略。演化博弈方法的引入为知识创造行为和组织惯例的研究开辟了全新视角,也为相关领域的进一步探索提供有利的理论支持。     

实践社群知识扩散模型及仿真研究

实践社群知识扩散的效率和效果影响实践社群的创新能力。通过考虑实践社群成员知识异质性对知识扩散的影响,引入知识生态位的观点,比较实践社群成员知识生态位的重叠程度,进而构建实践社群知识扩散模型,考虑实践社群成员间的相互作用,对知识扩散模型进行求解,得到相应的稳定均衡点并利用相图分析法进行验证,最后利用MATLAB进行数值仿真研究。结果表明:实践社群成员知识生态位的重叠程度对知识扩散效果有重要影响,实践社群成员间影响程度的大小对实践社群知识扩散模型均衡点有显著影响,实践社群成员知识表现为知识互补时,实践社群知识扩散的效率与效果最优。研究结果为促进实践社群知识扩散提供理论依据。     

生成学习系统的混沌与设计

认知学习是一种高度复杂的非线性现象.试图依据生成学习理论和经验学习的思想,建构含有记忆效应的生成学习系统动力学模型,探讨认知学习过程的复杂现象和变化特征,揭示学习系统波动的内生机制和学生认知的混沌规律,并在此基础上提出基于学习混沌的教学系统设计模式,期望能促进学生认知结构的发展.     

A High-Quality Preconditioning Technique for Multi-Length-Scale Symmetric Positive Definite Linear Systems

We study preconditioning techniques used in conjunction with the conjugate gradient method for solving multi-length-scale symmetric positive definite linear systems originating from the quantum Monte Carlo simulation of electron interaction of correlated materials. Existing preconditioning techniques are not designed to be adaptive to varying numerical properties of the multi-length-scale systems. In this paper, we propose a hybrid incomplete Cholesky (HIC) preconditioner and demonstrate its adaptivity to the multi-length-scale systems. In addition, we propose an extension of the compressed sparse column with row access (CSCR) sparse matrix storage format to efficiently accommodate the data access pattern to compute the HIC preconditioner. We show that for moderately correlated materials, the HIC preconditioner achieves the optimal linear scaling of the simulation. The development of a linear-scaling preconditioner for strongly correlated materials remains an open topic.