Accelerated sequential procedure for selecting the largest mean

From K(≧2) independent normal populations, we wish to select the one associted with the largest mean, assuming that the comman variance is unknown. We adopt the “indifference Zone” approach of Bechhofer (1954) and propose an accelerated version of the purely sequential procedure of Robbins et al. (1968). Asymptotic second order expansions for the probability of correct selection and other characteristices of this modified rule are provided for arbitrary K. We discuss both small and moderate sample size performances of our stopping time via computer simlations and note that the accelearted version can save considearable amout of sampling operations, yet it can be very competitive with the classical sampling procedure of Robbins et al. (1968).     

山区三维地震勘探技术

根据山区三维地震勘探的技术特点,有针对性地对三维地震的激发条件、接收条件、地震资料处理等常规问题进行了分析,并提出了相应技术方案及施工措施,以新疆某山区三维勘探为例,介绍了山区三维地震勘探施工方法及处理效果,为进一步开展山区地震勘探积累了经验。     

连续镀锌线退火炉氢氮混合站控制

在连续镀锌线生产过程中,由于退火炉内氢氮混合气的质量直接影响热镀锌带钢的品质,所以氢氮混合站的可靠性关系到连续镀锌线的正常运行。武汉钢铁集团公司二冷轧连续镀锌线立式退火炉氢氮混合站引进比利时Drever公司技术,对氢氮混合站采用4种控制模式,在不同的工况下各模式间采用相应的切换顺序。系统通过对H2和N2流量的精确控制,使得混合气中H2体积分数稳定在工艺要求的5%,其控制精度保持在±0.1%以内。本文介绍氢氮混合站的过程控制流程,PLC系统构成和主要控制功能的实现。     

Does incorrect guessing impair fact learning?

Taking a test has been shown to produce enhanced retention of the retrieved information. On tests, however, students often encounter questions the answers for which they are unsure. Should they guess anyway, even if they are likely to answer incorrectly? Or are errors engrained, impairing subsequent learning of the correct answer? We sought to answer this question in 3 experiments. In Experiments 1 and 2, subjects read 80 obscure facts (e.g., “Where is Disko Island? Greenland”) and then took a cued recall test. When a subject reported being unable to answer a question, on a randomly chosen half of those questions the computer program insisted upon a guess. Corrective feedback was provided either immediately (Experiment 1) or after a delay (Experiment 2). Forced guessing did not affect subjects' performance on a final test given 1 day later. We extended the investigation to more complex material in Experiment 3. Subjects saw a question (e.g., “Why do ice cubes often pop as they melt in your drink?”) and its answer, but for half of the questions, subjects did not see the answer until they first provided a plausible explanation. On a test administered either on the same day or 1 week later, recall performance was again unaffected by a prior wrong guess. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Selection among Bernoulli populations in comparison with a standard

Abstract

In this article we consider the problem of comparing several Bernoulli populations in order to identify the population producing the largest success probability that is also larger than a given standard. We propose a fixed sample size procedure for which we develop the probability of a correct selection and the least favorable configuration. We also propose a curtailed version of the fixed sample size procedure and show that the curtailed procedure reaches the same probability of a correct selection as the fixed sample size procedure, while using fewer observations. We provide tables to implement the procedures and illustrate them via an example. We use simulations to estimate the savings by the curtailment procedure.     

带差动保护高压电动机更换电机的方法

分析异步电动机差动保护原理,提出带差动保护的电动机更换电机的方法。     

多传感器数据融合评估系统的设计与实现

多传感器数据融合技术现已成为研究热点,但对它的研究往往缺乏必要的仿真手段和评估手段。为不断验证和改进融合系统的融合算法,设计并实现了一个多传感器数据融合评估系统：首先建立了评估系统的模型;接着对评估指标,按精度、相关性和处理能力三方面内容,给出了详细定义和计算方法;并针对评估实现中的关键问题,给出了基于最近邻域的相关技术、基于自适应均值门限判断的正确航迹判断技术和基于Matlab的可移植编程技术等解决方法。仿真实验表明,评估指标设计合理,评估系统切实可用。     

开关电源的优化设计研究

文中介绍本开关电源的优化设计要点,以通信用-48V开关电源为例子,阐述设计实现过程。本设计以89C52单片机为控制核心,利用AC／DC电源控制芯片（iw1692）,系统采用数字控制方式,对系统作了软件设计。     

柴油机齿轮室盖功能量规设计

简介柴油机齿轮室盖功能量规的设计原理，依据GB／T8069-1998《功能量规》的规定，计算位置量规工作部位的尺寸：检验部位的尺寸及磨损极限的尺寸，并对量规图样及量规的使用作了简要的说明。