国外爆炸物探测与识别技术综述

综述了国外爆炸物探测与识别所采用的微量炸药探测和块体炸药探测两大类技术,讨论了每类技术所采用的探测方法及其工作原理.介绍了目前国外的探测设备,根据每种探测技术和探测设备在使用中存在的不足,对其今后可能的发展趋势作了进一步探讨.     

湿式微细粒分级设备发展动态与分析

微细粒分级是现代制粉技术的关键 ,分级设备正向粒度细、级别窄的方向发展 ,本文介绍了湿式微细粒分级的几种主要设备 ,并对各自的优缺点进行了初步的分析 ,对窄级别的微细粒分级提出了作者的观点     

基于BP网络星图识别的样本构造方法

星敏感器是一种高精度的姿态敏感测量系统，如何确定星敏感器上像点在摄影时刻所对应的恒星，即星图识别，是姿态测量的关键。本文根据星图识别问题本身的特点和神经网络技术的特性，提出了基于BP网络星图识别方法的一种可以兼顾性能和效率、利于实现的样本构造方法。     

提高星图识别正确率的方法研究

在CCD星敏感器中，快速而可靠的星图识别算法成为星敏感器确定姿态的最关键部分．针对星图识别误匹配的存在，通过实验数据探讨了采用不同的星图识别特征、增加参与星图识别的恒星数目、提高恒星位置测量精度和星等测量精度、使用不同的星图匹配门限、选取合适导航星等方法，提高星图识别正确率。实验结果表明，采用这些方法后，星图正确匹配概率大大提高．     

探讨采油生产安全管理的方法与对策

近年来,油田安全管理按照“全员排查、分工负责、分级治理、风险受控、确保安全”的原则,“抓源头、重预防”,以“我能安全”活动为主题,从管理层、执行层、操作层明确各级、各岗位职责,强化安全教育培训,查找不安全行为,消除设备、环境隐患,进行风险识别与评估,发挥值班长作用,实现了采油全员全过程的安全生产。     

探讨采油生产安全管理的方法与途径

近年来,油田安全管理按照“全员排查、分工负责、分级治理、风险受控、确保安全”的原则,“抓源头、重预防”,以“我能安全”活动为主题,从管理层、执行层、操作层明确各级、各岗位职责,强化安全教育培训,查找不安全行为,消除设备、环境隐患,进行风险识别与评估,发挥值班长作用,实现了全员全过程的安全生产。     

浅析物联网技术及其发展前景

在物联网中要用到射频识别（RFID）装置、红外感应器、全球定位系统、激光扫描器等信息传感设备。物联网的关键部分就是信息识别和传感技术,这两关键部分都主要依靠射频识别（RFID）技术。     

探讨企业安全生产管理的方法与对策

近年来,油田安全管理强调“全员排查、分工负责、分级治理、风险受控、确保安全”的原则,“抓源头、重预防”。桩西采油厂作业大队以“我能安全”活动为主题,从管理层、执行层、操作层明确各级、各岗位职责,强化安全教育培训,查找不安全行为,消除设备、环境隐患,进行风险识别与评估,发挥值班长作用,实现了全员全过程的安全生产。     

基于深度学习算法的矿用巡检机器人设备识别

为了实现矿用巡检机器人对煤矿井下设备的识别与匹配,通过基于卷积神经网络的深度学习算法建立了煤矿设备类型识别模型,分别在明亮环境下、昏暗环境下以及设备重叠情况下采集大量待识别设备图像样本,再对识别模型进行训练,实现巡检机器人对煤矿设备的精确识别与分类。使用基于粒子群优化的SVM（support vector machine,支持向量机）建立了煤矿设备匹配模型,将巡检机器人相对于煤矿坐标系的三轴位置信息、三自由度角度和视觉相机转角作为匹配模型的输入量,将相机视野中设备序号作为输出量,实现煤矿设备类型识别模型识别出的设备与已知设备序号一一对应。实验结果表明基于深度学习算法的煤矿设备类型识别模型对外界的干扰不敏感,识别准确率高;基于SVM的煤矿设备匹配模型的匹配准确率达到了93.2%,在匹配准确率的训练和测试效率上均优于基于BP（back propagation,反向传播）神经网络的匹配模型。研究结果可为煤矿井下巡检机器人的研制提供参考。     

三维成像声呐图像重建研究

针对成像声呐领域中水下目标探测、识别等问题,基于三维探测声呐2304通道波束形成数据,研究三维成像声呐可视化方法,仿真了三维点云重构算法,并根据实际应用需求,在设备实现中改进了算法,使其在实际环境中可动态调节阈值,优化成像效果。水池、湖试实验表明:以该可视化方法为基础的三维探测声呐可正确显示目标位置、形态;且在混响环境中对复杂探测目标有良好的重构效果;同时通过与二维声呐图像对比,进一步验证了该三维声呐在轮廓识别方面的优越性。     

基于风险管控体系的爆破作业单位信息化安全管理初探

安全管理的重点是风险管控,风险管控的核心是形成安全预控手段和机制。针对爆破作业单位安全管理现状,运用风险管理的基本理论,通过风险辨识、风险评估、风险分级以及风险管控4个环节,建立了爆破作业单位的安全风险分级管控体系;结合物联网技术、大数据分析、人工智能和智能化平台等预控技术,将信息智能化手段运用到爆破作业单位的安全管理,实现了爆破作业单位安全管理的信息化。     

High temperature crack initiation and defect assessment of P22 steel weldments using time dependent failure assessment method

High temperature deformation and crack resistance of low alloy ferritic grade P22 steel weldments applied in power plants are reported. The creep crack initiation (CCI) and creep crack growth (CCG) data were determined using compact type (C(T)) and C-Shape (CS(T)) fracture mechanics specimens at 550 °C. The deformation and crack growth behaviour of similar weldment zones and significance of CCI and CCG in defect assessment of components were addressed. The weldments with industrially relevant properties were produced in butt welded pipe joint from which test specimens are sampled. The studied material covers a spectrum of microstructures and ductility over the weldment zones to give representative for a welded component. The emphasis is placed on the measurement and particularly analysis of crack initiation for failure assessment in P22 steel weldments. The particular importance of construction of isochronous curves for time dependent failure assessment diagram (TDFAD) method is reported. It is aimed to contribute to establishing guidelines for acceptable methodologies for testing, analysis and assessment of welded components using TDFAD for high temperature service.     

PCA-based feature selection scheme for machine defect classification

The sensitivity of various features that are characteristic of a machine defect may vary considerably under different operating conditions. Hence it is critical to devise a systematic feature selection scheme that provides guidance on choosing the most representative features for defect classification. This paper presents a feature selection scheme based on the principal component analysis (PCA) method. The effectiveness of the scheme was verified experimentally on a bearing test bed, using both supervised and unsupervised defect classification approaches. The objective of the study was to identify the severity level of bearing defects, where no a priori knowledge on the defect conditions was available. The proposed scheme has shown to provide more accurate defect classification with fewer feature inputs than using all features initially considered relevant. The result confirms its utility as an effective tool for machine health assessment.     

Modeling of the resilient supply chain system from a perspective of production design changes

Building an effective resilient supply chain system (RSCS) is critical and necessary to reduce the risk of supply chain disruptions in unexpected scenarios such as COVID-19 pandemic and trade wars. To overcome the impact of insufficient raw material supply on the supply chain in mass disruption scenarios, this study proposes a novel RSCS considering product design changes (PDC). An RSCS domain model is first developed from the perspective of PDC based on a general conceptual framework, i.e., function-context-behavior-principle-state-structure (FCBPSS), which can portray complex systems under unpredictable situations. Specifically, the interaction among the structure, state and behavior of the infrastructure system and substance system is captured, and then a quantitative analysis of the change impact process is presented to evaluate the resilience of both the product and supply chain. Next, a case study is conducted to demonstrate the PDC strategy and to validate the feasibility and effectiveness of the RSCS domain model. The results show that the restructured RSCS based on the proposed strategy and model can remedy the huge losses caused by the unavailability of raw materials.     

面向供应链的大规模定制时间阈值理论研究

针对目前大规模定制管理运作策略中存在的主要问题,以探索提升面向供应链环境下的大规模定制生产过程中的客户服务水平为主线,在对用户订单信息特征分析与合理分类的基础上,通过引入时间阈值概念及相关理论作为协调大规模定制中范围经济同客户定制化服务水平之间矛盾的基本解决思路,并分析了影响时间阈值的各主要因素,同时在时间阈值的前提下,提出了面向供应链的大规模定制管理运作多级优化策略的思想。     

A synergetic approach for assessing and improving equipment performance in offshore industry based on dependability

The objective of this paper is to present a framework for assessing and improving offshore equipment performance based on dependability. The main idea is to employ principle component analysis (PCA) and importance analysis (IA) to provide insight on the equipment performance. The validity of the model is verified and validated by data envelopment analysis (DEA). Furthermore, a non-parametric correlation method, namely, Spearman correlation experiment shows a high level of correlation between the findings of PCA and DEA. The equipment of offshore industries is considered according to OREDA classification. The approach identifies the critical equipment, which could initiate the major hazards in the system. At first PCA is used for assessing the performance of the equipment and ranking them. IA is then performed for the worst equipment which could have most impact on the overall system effectiveness to classify their components based on the component criticality measures (CCM). The analysis of the classified components can ferret out the leading causes and common-cause events to pave a way toward decreasing failure interdependency and magnitude of incidents which ultimately maximize overall operational effectiveness.     

A comparison of stress intensity factors obtained through crack closure integral and other approaches using eXtended element-free Galerkin method

In this paper, a new approach for extracting stress intensity factors (SIFs) by the extended element-free Galerkin method, through a crack closure integral (CCI) scheme, is proposed. The CCI calculation is used in conjunction with a local smoothing technique to improve the accuracy of the computed SIFs in a number of case studies of linear elastic fracture mechanics. The cases involve problems of mixed-mode, curved crack and thermo-mechanical loading. The SIFs by CCI, displacement and stress methods are compared with those based on the M-integral technique reported in the literature. The proposed CCI method involves very simple relations, and still gives good accuracy. The convergence of the results is also examined.     

二维主元分析法在心肌梗死心电信号检测中的应用

利用基于联合能量百分比搜索的二维主元分析法对12导高分辨率心电信号（ECG）进行全局特征提取和分类检测研究。所用数据取自PTB诊断数据库,包括健康状态ECG,早期心肌梗死（MI）ECG,急性期MI ECG,恢复期 MI ECG。结果表明,所用的方法能有效地融合12导ECG信号及其高频分量中的细微结构信息,与常规主元分析法相比,其平均分类检测精度可提高10.43%,与常规二维主元分析法相比,能得到维数更低的特征表示,并可获得99.46 %的平均分类检测精度。     

Performance analysis of decision-feedback equalisation for cellular mobile radio with cochannel interference and fading

The error probability of minimum-mean-square-error decision-feedback equalisation (MMSE-DFE) is evaluated for digital cellular mobile radio systems in the presence of cochannel interference (CCI) and is compared with linear equalisation (LE). The main contribution of the paper is that this analysis accounts for pulse waveform, modulation and fading of the signal of interest, as well as the CCI. Quadrature-amplitude modulation (QAM) signalling in frequency-selective and quasi-static channels is considered. The CCI is treated as a stationary process, when caused by random phase and symbol-timing offsets relative to the signal of interest. Analysis includes techniques combining antenna diversity. The performance improvement as a function of taps in both feedforward and feedback filters is quantified. Owing to residual intersymbol interference (ISI) and CCI, the evaluation of the error probability is extremely complicated and time consuming in simulation. To overcome this issue, an efficient method based upon Gauss quadrature rules (GQR) is presented to compute the error probability. The method is not limited due to interference statistics and it yields remarkable advantages compared with other methods. The convergence of finite-length results to their infinite-length counterparts is also provided. Unlike the case of white noise, the simulations reveal that with the same finite length the DFE is unable to outperform the linear equaliser in a CCI-dominated channel if the feedback filter is of insufficient length.     

基于CFD-DEM耦合的水平井PDC钻头水力结构研究

钻采深层页岩气的水平井段多为泥岩、页岩等黏性地层,为提高钻井效率和减少钻头泥包的发生,必须保证井底岩屑被快速运移,这对PDC （polycrystalline diamond compact,聚晶金刚石复合片）钻头的水力结构提出了要求。为此,基于CFD-DEM （computational fluid dynamics-discrete element method,计算流体动力学-离散单元法）耦合方法,对水平井PDC钻头井底流场进行数值模拟分析,并以岩屑滞留量和岩屑运移比作为评价指标,对直径为152.4 mm的五刀翼PDC钻头的流道形状、喷嘴数量、喷嘴排布方式及喷嘴直径等水力结构参数进行分析。最后,对水力结构改进后的PDC钻头进行现场应用。数值模拟结果表明：流道形状为抛物线型的PDC钻头具有更好的携岩性能;在总喷射面积相同的情况下,PDC钻头应采用较少数量的喷嘴;喷嘴等径排布的PDC钻头的携岩性能优于非等径排布的;在一定范围内,适量减小PDC钻头喷嘴直径有利于岩屑运移。现场应用结果表明,在同区块、同地层的多个水平井段钻进时,水力结构改进后PDC钻头的钻井效率更高。研究结果可为PDC钻头结构优化提供参考。