Automating application software generation

Many approaches have been proposed to enhance software productivity and reliability. These approaches typically fall into three categories: the engineering approach, the formal approach and the knowledge-based approach. But the optimal gain in software productivity cannot be obtained if one relies on only one of these approaches. This paper describes the work in knowledge-based software engineering conducted by the authors for the past 10 years. The final goal of the research is to develop a paradigm for software engineering which integrates the three approaches mentioned above. A knowledge-based tool which can support the whole process of software development is provided in this paper.     

分置式牛津型斯特林制冷机的数值分析与实验验证

对分置式牛津型斯特林制冷机进行了数值计算 ,介绍了计算模型考虑到的众多不可逆因素。通过对计算结果与实验结果的对比 ,验证了本文数值计算的准确性 ,说明本文计算模型与数值处理方法是切实可行的     

一种新的变步长ICA自适应算法

结合互信息极小的优化判据，基于估计函数期望平方准则、外点法和最速下降法的思想，本文导出了一种新的变步长独立分量分析(ICA)自适应算法。该算法克服了固定步长在分离矩阵推导过程中出现的稳态失调问题，比基于模拟退火步长的ICA算法有更快的仞始收敛速度和较高的分离精度。同时，该算法还具有较好的时变系统跟踪能力。理论分析和仿真计算结果证实了其可以有效地提高ICA的自适虚性，更准确地完成盲信号分离。     

基于复数主成分分析的磁共振波谱信号衰减系数的自动校正

衰减系数的校正是磁共振波谱信号处理和分析过程中的一个关键难题。本文基于复数主成分分析，提出了一种自动的磁共振波谱衰减系数的校正方法，较成功地解决了这个难点问题。文中的模拟数据及其实现结果充分验证了该方法的有效性。     

对一起氮压机燃爆事故的原因分析

SVK8 3S型氮气压缩机是由沈阳鼓风机厂制造、为义马煤气配套的低压氮气压缩机 ,共两套 ,于 2 0 0 0年 1 2月开始调试。为节约工程基建资金 ,取消原设计两台中压氮气压缩机 ,由杭氧产两台3TYS89+2TYS60型氧气透平压缩机临时压送氮气 ,向外供中压氮 ,来取代中压氮气压缩机 ,流程示意图如图 1所示。图 1　氧、氮压机工艺流程配置图1　事故情况2 0 0 0年 1 2月 2 7日中午 1 1∶3 5 ,接总调度室通知 ,要求中午 1 2∶0 0向长输管线供中压氮气。当时 ,一台氮压机试车完毕正在运行 ,一台氧压机试车完毕压氧正在运行 ,将由氧压机临时压送氮气外供…     

Extracting Modes of Constrained Structure with Elastic Supports from Free Test Data

The dynamic flexibility (DF) and improved dynamic flexibility (IDF) methods can be applied to extract constrained structural modes from free-free modal test data. The residual flexibility method is also good for boundaries of constrained structure with rigid supports. Under elastic support boundary conditions both the DF and residual flexibility methods cannot produce accurate results. This paper expands the previously published IDF method to become a more general approach for structural design engineers. A new method called the general dynamic flexibility (GDF) method has been developed in this paper to extract constrained structural modes from free test data. The GDF method can always be applied as follows: (1) when the boundary support stiffness is very stiff, the GDF method can accurately obtain results from rigid support as by Liu et al. in 2001 and Zhang and Wei in 2003; (2) when the support stiffness is soft, the present method can produce results similar to those free-free modal parameters measured by hanging structures using rubber band; (3) when the support stiffness is zero, the method can reproduce true free-free modal parameters; and (4) when the support stiffness has any finite values, the GDF method can also achieve satisfactory results for engineering use. The algorithm included in the GDF method converges rapidly and is numerically stable in the analysis. This feature is very practical for many engineering applications for using the GDF method.     

行政权力腐败的模型分析及治理对策

腐败是与政府行政权力相伴生的痼疾，既是一个历史现象又是一个国际现象。贪污腐败和寻租腐败是委托一代理模型中最典型的腐败方式，文章在此基础上对贪污腐败和寻租腐败进行成本一收益分析和市场均衡分析，并探讨治理行政权力腐败的有效途径。     

Significance of the elastic peak stress evaluated by FE analyses at the point of singularity of sharp V-notched components

The paper presents an expression useful to estimate the notch stress intensity factor (NSIF) from finite element analyses carried out by using a mesh pattern with a constant element size. The evaluation of the NSIF from a numerical analysis of the local stress field usually requires very refined meshes and then large computational effort. The usefulness of the presented expression is that (i) only the elastic peak stress numerically evaluated at the V‐notch tip is needed and no longer the whole stress–distance set of data; (ii) the adopted meshes are rather coarse if compared to those necessary for the evaluation of the whole local stress field. The proposed expression needs the evaluation of a virtual V‐notch tip radius, i.e. the radius which would produce the same elastic peak stress than that calculated by FEM at the sharp V‐notch tip by means of a given mesh pattern. Once such a radius has been theoretically determined for a given geometry, the expression can be applied in a wide range of notch depths and opening angles.     

Finite-element analysis and experimental study on tensile fatigue behaviour of bitumen–stone adhesion

Tensile fatigue behaviours of bitumen–stone adhesion were investigated using a dynamic mechanics analyser under stress‐controlled mode at two temperatures of 5 and 25°C and various controlled‐stress levels. Failure characteristics including interfacial failure and cohesive failure were examined using image analysis of fracture surfaces. Finite‐element analysis on stress distributions was conducted under different temperatures, film thickness and interfacial bonding conditions. A Coulomb–Mohr like criterion in combination with shear and normal stresses is proposed to deal with the extreme thin adhesive layer, which can be further simplified into an adhesive zone without significant loss of accuracy for stress analysis.