PDM系统在企业中的实施

以新疆石油管理局机械制造总公司PDM系统为例,介绍了企业在实施PDM系统前面临的问题、实施目标的确立、软件的选择和实施步骤与体会。     

基于WLSE-KF的传感器融合定位算法研究

多传感器融合在定位中的应用越来越广泛。在利用这些传感器进行定位的过程中,需要对其采集的数据进行融合。射频识别融合定位一般采用最小二乘法,然而,它可能使定位误差较大。文中提出了将最小二乘和卡尔曼滤波相结合的算法。该算法先利用加权最小二乘估计获得移动用户的初步位置,再利用扩展卡尔曼滤波进一步使定位精度得到提高。仿真结果表明该算法相比多种传统定位算法,误差减少,定位精度明显提高。     

基于USB接口的数据采集与控制系统设计

利用ADuC845单片数据采集器件和CH341USB接口器件构成的数据采集与控制系统．具有10个24位的MD转换器输入通道,60Hz范围内有20位有效分辨率,失调漂移10nV／℃,12位电压输出D／A转换器,双16位PWM输出,8路开关量输入,输出,支持全速设备接口USBV1．1,通讯波特率可达50b／s～2Mb／s,适用于医疗设备、工业控制系统等数据采集与控制领域。     

地下水功能评价指标标准化过程中的异常数据识别及处理

地下水功能评价指标标准化是实现地下水功能评价定量评价的关键步骤,在量化过程中隐含一些数据处理方法,采取的方法得当与否直接关系到评价结果的准确性,相应地就决定对此结果采取措施和方案的有效性。以西辽河平原地下水功能评价中的实际数据为例,给出一套评价指标异常数据识别和处理的方法。     

Influence of Process Variables on the Bending Strength of Particleboard Produced from Arabian Date Palm Mid-Rib Chips

Feed produced from Arabian date palm (Phoenix dectylifera-L) biomass and impregnated with urea formaldehyde (UF) adhesive binder is subjected to hot compaction to yield particleboard panels of excellent bending strength. Process variables such as press temperature, press cycle time, compaction pressure and particle thickness are shown to exercise significant effects on the bending strength of the final product. The influence of chipping technique on particle integrity and surface quality is highlighted. Scanning electron microscopic (SEM) evidence is presented to illustrate microstructural damages caused by excessively high compaction pressure.     

工业生产实时数据采集及管理数据库模型设计

提出了中小型生产企业在企业信息化过程中的生产数据实时采集、安全存储、有效管理的重要性,并给出生产数据的自动统计、分析、处理及为企业的生产经营提供决策的手段。     

Computational methods for determining the latest starting times and floats of tasks in interval-valued activity networks

In project management, three quantities are often used by project managers: the earliest starting date, the latest starting date and the float of tasks. These quantities are computed by the Program Evaluation and Review Techniques/Critical Path Method (PERT/CPM) algorithm. When task durations are ill known, as is often the case at the beginning of a project, they can be modeled by means of intervals, representing the possible values of these task durations. With such a representation, the earliest starting dates, the latest starting dates and the floats are also intervals. The purpose of this paper is to give efficient algorithms for their computation. After recalling the classical PERT/CPM problem, we present several properties of the concerned quantities in the interval-valued case, showing that the standard criticality analysis collapses. We propose an efficient algorithm based on path enumeration to compute optimal intervals for latest starting times and floats in the general case, and a simpler polynomial algorithm in the case of series-parallel activity networks.     

Multicriterion genetic optimization for due date assigned distribution network problems

This paper focuses on the demand due date factor in multiechelon distribution network problems and its impact on the production scheduling in manufacturing plants. A reliable demand due date is critical in winning of customer orders. However, this may usually require high collaboration among entities in the network. Mismatching of one single schedule may seriously influence the reliability. In this connection, holistically optimizing the schedule of each entity among the network is essential. In addition, on time delivery may induce high operating cost. A trade-off between earliness, on time, and tardiness should also be considered. Hence, a multicriterion genetic optimization methodology is developed to holistically optimize them. It determines the optimized schedule to collaborate each entity to fulfill the demands. For enabling multicriterion decision-making, the proposed algorithm combines analytic hierarchy process with genetic algorithms (GAs). The problem is divided into two parts—(i) demand allocation and transportation problem, and (ii) production scheduling problem. The optimization approach is applied to iteratively optimize part (i), and then part (ii). Three experiments have been carried out, and the computation results show that the effect of due date is critical, and the ability of the proposed algorithms in taking trade-off between earliness and tardiness.     

面向SOC设计的混合验证方法及其应用

本文介绍一种基于断言的形式验证与仿真验证相结合的面向SOC的新的混合验证方法,并简要介绍其在数据完整性验证方面的应用实例。     

英文信函格式要点

英文信函与汉语信函在格式上存在差异.在英文信函写作中应注意英文信函的具体格式要求,包括地址写作格式、信封写作格式、日期表达格式、称谓语及结束语的选用、信函内文格式等.文章阐述了英文信函的正确格式.