基于相互作用矩阵的EPC地铁项目采购风险评价

EPC地铁项目采购活动是一个极为复杂的风险系统,涉及多种采购风险因子的相互耦合关系。为了克服传统评价方法的缺陷,基于多因素耦合的视角,采用相互作用矩阵法综合分析多因素间的交互耦合作用对整个系统的影响。研究发现,导致地铁项目采购风险发生的本质原因是合约、技术、管理、运输及仓储、环境5种因素间相互作用的结果。实际案例的引入更为客观地证实了多因素间的相互作用关系,既丰富了对EPC地铁项目采购风险的评价方法,又可为项目管理者规避和降低采购风险提供参考。

生产设备与部件风险辨识方法的探究

风险辨识是风险评估整个过程的基础和关键。随着社会的发展,生产技术、设备的不断更新,以往依靠风险评估人员自身素质和经验的安全评估方法已不能满足对企业生产设备与部件风险辨识完整性的要求。本文结合相互作用矩阵法的思想,针对企业生产操作过程中涉及的设备与部件,按照生产流程及功能设定划分成若干分析节点,并从人与设备、设备与设备/部件与设置、部件相互作用三个方面出发,对其涉及到的风险进行了辨识,使得辨识结果更具系统性和完整性。最后针对风险辨识过程中的一些问题提出了相应的改善对策。

Risk assessment of floor water inrush in coal mines based on MFIM-TOPSIS variable weight model

Floor water inrush is one of the main types of coal mine water hazards.With the development of deep mining,the prediction and evaluation of floor water inrush is particularly significant.This paper proposes a variable weight model,which combines a multi-factor interaction matrix(MFIM)and the technique for order performance by similarity to ideal solution(TOPSIS)to implement the risk assessment of floor water inrush in coal mines.Based on the MFIM,the interaction between seven evaluation indices,including the confined water pressure,water supply condition and aquifer water yield property,floor aquifuge thickness,fault water transmitting ability,fracture development degree,mining depth and thickness and their influence on floor water inrush were considered.After calculating the constant weights,the active degree evaluation was used to assign a variable weight to the indices.The values of the middle layer and final risk level were obtained by TOPSIS.The presented model was successfully applied in the 9901 working face in the Taoyang Mine and four additional coal mines and the results were highly consistent with the engineering situations.Compared with the existing nonlinear evaluation methods,the proposed model had advantages in terms of the weighting,principle explanation,and algorithm structure.

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 pattem 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.

Darboux Transformations and N-soliton Solutions of Two (2+1)-Dimensional Nonlinear Equations

Two Darboux transformations of the(2+1)-dimensional Caudrey–Dodd–Gibbon–Kotera–Sawaka(CDGKS)equation and(2+1)-dimensional modified Korteweg-de Vries(mKdV) equation are constructed through the Darboux matrix method, respectively. N-soliton solutions of these two equations are presented by applying the Darboux transformations N times. The right-going bright single-soliton solution and interactions of two and three-soliton overtaking collisions of the(2+1)-dimensional CDGKS equation are studied. By choosing different seed solutions, the right-going bright and left-going dark single-soliton solutions, the interactions of two and three-soliton overtaking collisions, and kink soliton solutions of the(2+1)-dimensional mKdV equation are investigated. The results can be used to illustrate the interactions of water waves in shallow water.