大型MIS系统的复合开发方法

本文介绍了软件开发的生命周期法和快速原型法的基本思想及其局限性,并将两种开发方法相结合,提出了一种大型MIS系统的复合开发方法,以实现快速有效地开发MIS系统。     

How causal knowledge simplifies decision-making

Making decisions can be hard, but it can also be facilitated. Simple heuristics are fast and frugal but nevertheless fairly accurate decision rules that people can use to compensate for their limitations in computational capacity, time, and knowledge when they make decisions [Gigerenzer, G., Todd, P. M., & the ABC Research Group (1999). Simple Heuristics That Make Us Smart. New York: Oxford University Press.]. These heuristics are effective to the extent that they can exploit the structure of information in the environment in which they operate. Specifically, they require knowledge about the predictive value of probabilistic cues. However, it is often difficult to keep track of all the available cues in the environment and how they relate to any relevant criterion. This problem becomes even more critical if compound cues are considered. We submit that knowledge about the causal structure of the environment helps decision makers focus on a manageable subset of cues, thus effectively reducing the potential computational complexity inherent in even relatively simple decision-making tasks. We review experimental evidence that tested this hypothesis and report the results of a simulation study. We conclude that causal knowledge can act as a meta-cue for identifying highly valid cues, either individual or compound, and helps in the estimation of their validities.     

低压大型化工贮罐优化设计浅谈

大型贮罐的设计与一般压力容器有较大区别,力求归纳一下这方面的经验并结合工程实例,供广大设计和工程部门的同行借鉴。     

Using geometric Poisson exponentially weighted moving average control schemes in a compound Poisson production environment

In this study, the variable to be controlled over time is the number of defects. Meanwhile, the underlying distribution of defects is the geometric Poisson distribution, a Poisson distribution compounded by a geometric distribution. For production process control, the exponentially weighted moving average (EWMA) control scheme based on the geometric Poisson process is addressed. Performance of the EWMA control scheme is assessed not only by both in-control and out-of-control average run lengths (ARL’s), but also by higher moments of the run length (RL) distribution. The run length distribution properties can be obtained from the probability transition matrix and implemented using the computer programs developed in this study. With proper ARL and variance of RL selected, any small shift in mean can be detected via the geometric Poisson EWMA control scheme.     

Deformation effect of lateral roof roadway in close coal seams after repeated mining

This paper analyzed the deformation mechanism in lateral roof roadway of the Ding Wu-3 roadway which was disturbed by repeated mining of close coal seams Wu-8 and Wu-10 in Pingdingshan No. 1 Mine. To determine the strata disturbance scope, the strata displacement angle was used to calculate the protection pillar width. A numerical model was built considering the field geological conditions. In simulation, the mining stress borderline was defined as the contour where the induced stress is 1.5 times of the original stress. Simulation results show the mining stress borderline of the lateral roadway extended 91.7 m outward after repeated mining. Then the original stress increased, deforming the roadway of interest. This deformation agreed with the in situ observations. Moreover, the strata displacement angle changed due to repeated mining. Therefore, reselection of the displacement angle was required to design the protective pillar width. Since a constant strata displacement angle was used in traditional design, the proposed method was beneficial in field cases.     

隧道洞口段不同围岩刚度下管棚的支护效果分析

以某高速公路隧道为例,采用FLAC3D有限差分程序建立考虑管棚预加固效应的三维数值仿真模型,对隧道洞口段不同围岩刚度下管棚支护体系对地层稳定的控制效果进行模拟分析.结果表明:管棚可以起到较好的荷载传递作用,有效控制开挖释放荷载引起的地层位移;土体刚度越大,地层沉降越小,管棚与土体之间的刚度比就越小,管棚的骨架作用随之逐渐减弱,相应地管棚对地层沉降的控制程度也逐渐降低.     

基于支持向量机集成算法的煤矿顶板状态检测

针对小样本、多类煤矿顶板的状态检测问题,提出了基于支持向量机集成的算法。采用深度优先搜索对支持向量机集成参数进行优化,并结合煤矿顶板敲击声信号的人耳听觉功率谱特征,对煤矿顶板中浮石、剥层等现象进行分类识别。实验表明,该算法能够对多类顶板状态进行有效分类,且识别率较高,能够作为安全开采的保障手段。     

《说文解字》与许慎哲学思想浅析

阐述了许慎《说文解字》中所包含的历史的唯物的文字观和唯心主义的文字学思想,并从时代、社会和作者自身两个角度对许慎《说文解字》中哲学思想的二元性进行了剖析。     

顶板隔水层关键层耦合作用规律研究

在煤矿开采过程中，如果覆岩裂隙扩展至贯穿隔水层，则会诱发地下水或地表水大量涌向采场，导致煤矿淹井事故．利用RFPA^2D-Flow软件建立了隔水层关键层耦合的采场推进模型，计算并分析了裂隙场的发育和分布，绘制了顶板水渗流量曲线．讨论了与裂隙发育密切相关的覆岩支承压力与中间岩层厚度、关键层厚度及破断闻的关系．结果表明：关键层未破断时，中问岩层厚度对隔水层裂隙发育作用不明显；厚关键层对隔水层能起较好的保护作用．     

Flow resistance in a compound gravel-bed bend

In this paper, the effect of a gravel-bed in a compound bend (similar to sinusoidal top view) of a natural river (Zayandehrud River flowing through Isfahan, Iran) has been investigated for flow resistance analysis, measuring the velocity with a micro current meter. The data were analysed and the following observations were made. In a compound bend, the law of the wall can be valid for up to 66% of the flow depth from the bed. The parabolic law is the most effective method for the determination of shear velocity. Based on the existing criteria for verifying the equilibrium boundary layer, the flow cannot be in equilibrium. The shear stress distribution and the sediment transport parameters have considerable influence on resistance to flow. Froude number and the flow depth relative to the representative gravel size have little effect on the flow resistance estimation.