Some iterative algorithms for the obstacle problems

In this paper we propose some iterative algorithms for the obstacle problems discretized by the finite difference method. We rewrite the obstacle problem to an equivalent complementarity problem. We use the regularization trick to non-smooth absolute function. Then we apply the Newton's method to obtain an iterative algorithm. Some other two algorithms based on this algorithm are derived. Numerical experiments show the effective of the algorithm.     

Calderon's preconditioning for periodic fast multipole method for elastodynamics in 3D

Preconditioning methods based on Calderon's formulae for the periodic fast multipole method for elastodynamics in 3D are investigated. Three different types of formulations are proposed. The first type is a preconditioning just by appropriately ordering the coefficient matrix without multiplying preconditioners. The other two types utilise preconditioners constructed using matrices needed in the main fast multipole method algorithms. We make several numerical experiments with proposed preconditioners to confirm the efficiency of these proposed methods. We also conclude that the preconditioning of the first type is faster with respect to the computational time than other preconditioning methods discussed in this article. Copyright © 2012 John Wiley & Sons, Ltd.     

我国城市地理研究的学术规范问题

改革开放以来,我国大陆包括城市地理研究在内的城市研究取得了长足的进展,但在城市研究的学术规范方面也存在明显的不足。这种不足具体表现在问题意识不足、学术对话严重不足、引用不太规范、学术史意识不强及理论创新不够。只有正视这些问题,认真分析成因和思考对策,才有可能在已有成绩的基础上找准方向,重新出发,并找到通向世界学术的"桥梁"。本文对此作了尝试。     

B-spline method for solving Bratu's problem

In this paper, we propose a B-spline method for solving the one-dimensional Bratu's problem. The numerical approximations to the exact solution are computed and then compared with other existing methods. The effectiveness and accuracy of the B-spline method is verified for different values of the parameter, below its critical value, where two solutions occur.     

Analytic Function Expansion Nodal (AFEN) Method in Hexagonal-Z Three-Dimensional Geometry for Neutron Diffusion Calculation

The analytic function expansion nodal (AFEN) method in hexagonal-z geometry is described focusing on its unique features, including the use of node-interface flux moments. Multigroup extension based on matrix function theory and coarse group rebalance (CGR) acceleration are also described. The COREDAX code implementing the AFEN method is verified testing on the VVER-440 benchmark problem, a “simplified” VVER-1000 benchmark problem, and the SNR-300 benchmark problem.     

Identifying organizational barriers—A case study of usability work when developing software in the automation industry

This study investigates connections between usability efforts and organizational factors. This is an important field of research which so far appears to be insufficiently studied and discussed. It illustrates problems when working with software engineering tasks and usability requirements. It deals with a large company that manufactures industrial robots with an advanced user interface, which wanted to introduce usability KPIs, to improve product quality. The situation in the company makes this difficult, due to a combination of organizational and behavioural factors that led to a “wicked problem” that caused conflicts, breakdowns and barriers. Addressing these problems requires a holistic view that places context in the foreground and technological solutions in the background. Developing the right product requires communication and collaboration between multiple stakeholders. The inclusion of end users, who fully understand their own work context, is vital. Achieving this is dependent on organizational change, and management commitment. One step to beginning this change process may be through studying ways to introduce user-centred design processes.     

Parameterized ABD preconditioning technique for time-periodic convection–diffusion problems

In this paper, a parameterized additive block diagonal (PABD) preconditioning technique is present for solving the nine-point approximations of the time-periodic convection–diffusion problems. The explicit expressions for the eigenvalues and eigenvectors of the corresponding preconditioned matrices are presented. The range of the optimal parameters is derived. Numerical experiments show that the generalized minimal residual method preconditioned by the PABD preconditioner with the experimental optimal parameters or some special values is effective for a wide range of problem sizes.     

提升城市道路工程设计科学性的方法

受传统思想的影响，我国城市道路设计过多地照搬了公路设计模式，在以人为本、公交优先方面明显存在不足。通过分析城市道路工程设计中存在的常见问题，提出相关的解决措施，以期为提升我国城市道路工程设计的科学性贡献力量。