基于CSABC-ELM的采煤工作面瓦斯涌出量预测

为了提高煤矿工作面瓦斯涌出量的预测精度,研究一种将极端学习机(ELM)与利用混沌搜索策略改进的人工蜂群(CSABC)算法相结合的预测方法。改进后的人工蜂群算法有效解决了ABC算法易陷入局部最优、后期收敛慢等缺陷,利用CSABC优化ELM的输入层和隐含层参数,避免了随机产生ELM参数所造成的误差,建立基于CSABC-ELM的瓦斯涌出量预测模型。利用实际煤矿监测数据对该模型进行试验分析,并与ABC-ELM,ELM和BP神经网络的预测结果进行比较。结果表明,CSABC-ELM预测误差更小,精度更高,泛化性能也更强,能有效地对煤矿瓦斯涌出量进行预测。     

基于MPSO-WLS-SVM的矿井瓦斯涌出量预测模型研究

为有效预防瓦斯灾害,以预测矿井瓦斯涌出量为研究目的,提出经改进的粒子群算法(MPSO)优化的加权最小二乘支持向量机(WLS-SVM),并用其预测非线性动态瓦斯涌出量。算法通过对WLS-SVM的正则化参数C和高斯核参数σ寻优,建立基于MPSO优化的WLS-SVM的瓦斯涌出量预测模型,并利用某矿井监测到的各项历史数据进行实例分析。试验结果表明:该预测模型预测的最大相对误差为5.99%,最小相对误差为0.43%,平均相对误差为2.95%,较其他预测模型有更强的泛化能力和更高的预测精度。     

基于EMD-MFOA-ELM的瓦斯涌出量时变序列预测研究

为准确分析工作面绝对瓦斯涌出量的非平稳特征,实现瓦斯涌出量的准确预测,基于经验模态分解(EMD)、修正的果蝇优化算法(MFOA)和极限学习机(ELM)基本原理,构建瓦斯涌出量的EMD-MFOA-ELM多尺度时变预测模型。通过EMD将瓦斯涌出量时变序列进行深层次分解,获得多尺度本征模态函数(IMF);采用MFOA-ELM对各IMF时变序列建立动态预测模型,等权叠加各预测值,得到模型最终预测结果。以晋煤某矿瓦斯涌出量监测时序样本为例进行研究分析,结果表明:EMD能充分挖掘出监测数据隐含信息,有效降低数据复杂度;该模型预测相对误差为0.024 3%~0.651 0%,平均值仅为0.252 6%,预测精度和泛化能力高于未经EMD分解模型,能很好地适用于非平稳时变序列预测。     

基于蚁群神经网络的煤矿瓦斯预测模型

为了提高煤矿瓦斯涌出量的预测精度和预测速度,用蚁群算法和神经网络相结合的方法进行预测模型设计。选择瓦斯涌出的重要影响因素,建立其神经网络的预测模型。以网络的均方误差为目标函数,通过蚁群算法的迭代运算,实现BP网络的权值优化,并用优化好的BP网络进行瓦斯涌出预测。仿真结果表明,该方法具有较高的拟合预测精度。     

基于PSOBP-AdaBoost模型的瓦斯涌出量分源预测研究

为准确预测瓦斯涌出量,选取某煤矿的开采煤层、临近煤层、采空区3个瓦斯涌出源作为实例研究,将BP神经网络、粒子群算法(PSO)、Ada Boost迭代提升算法和瓦斯涌出分源预测法相结合,建立基于PSOBP-Ada Boost算法的瓦斯涌出量分源预测模型,并将其与BP神经网络算法进行比较分析。结果表明,PSOBP-Ada Boost算法预测的3个瓦斯涌出源平均相对误差分别为3.24%,2.11%,3.21%;BP神经网络的平均相对误差分别为6.73%,3.19%,4.27%,基于PSOBP-Ada Boost模型的预测精度明显优于BP神经网络模型。     

采煤工作面瓦斯涌出量预测的神经网络模型

正确预测瓦斯涌出量,对于指导矿井设计和安全生产有重要意义。为此,应用神经网络理论,建立了采煤工作面瓦斯涌出量的预测模型,对其影响因素进行了权重排序,并确定了关键因素。实际应用表明,预测模型可信,精度能满足要求。     

改进的Elman神经网络在瓦斯涌出量预测中的应用

在煤矿瓦斯灾害中,煤矿瓦斯突出是导致瓦斯重特大事故的主要原因之一。目前常用的基于反向传播(BP)神经网络和遗传算法-Elman神经网络(GA-ENN)耦合算法等建立瓦斯涌出量预测模型的预测方法在收敛性和精度上均存在一定的缺陷。提出了一种利用混沌免疫遗传优化算法(CIGOA)对Elman神经网络进行改进的新型智能优化算法来增强粒子的活性,提高其局部搜索能力和全局优化能力,克服了遗传算法(GA)的固有缺陷。对煤矿现场跟踪实测后进行仿真分析,结果表明:运用提出的CIGOA-ENN预测模型预测的最大相对误差为4.47%,最小相对误差为1.12%,平均相对误差为2.27%,明显小于BP神经网络和GA-ENN等预测模型的预测结果,表明CIGOA-ENN预测模型的输出结果更精确,对瓦斯涌出量预测系统的辨识误差更小,性能更优越。     

基于KPCA-CMGANN算法的瓦斯涌出量预测研究

为了精准预测瓦斯涌出量,针对绝对瓦斯涌出量非线性、时变性、复杂性等特点,提出采用核主成分分析法(KPCA)对影响因素进行降维处理;针对BP神经网络(BPNN)中存在的收敛速度慢和易陷入局部最优解的问题,采用压缩映射遗传算法(CMGA)优化BPNN;构建CMGA与BPNN的耦合算法(CMGANN),计算分析某低瓦斯矿井监测历史数据形成的样本集,建立KPCA-CMGANN预测模型;用KPCA-CMGANN预测模型和其他3种网络模型分别对煤矿现场数据进行预测。结果表明:KPCA-CMGANN预测模型在379个时间步长里达到收敛,4个回采工作面的瓦斯涌出量预测相对误差分别为0.58%、0.63%、0.57%和0.45%,平均相对误差仅为0.56%,预测精度和收敛速度均优于对比模型,可实现瓦斯涌出量的快速精准预测。     

SFLA-Verhulst组合模型预测矿井瓦斯涌出量

针对矿井瓦斯涌出量的时变性、波动性、非线性以及不确定性等特征,提出了SFLA-Verhulst组合预测模型,用于对具有非线性动态特征的瓦斯涌出量进行预测。该模型通过蛙跳算法对Verhulst模型的背景值参数寻优,并引入一次指数平滑法对原始数据进行优化处理,建立了基于混合蛙跳算法的SFLA-Verhulst组合预测模型;结果使模型在原始数据不准确或存在误差干扰的情况下仍能进行精度较高的预测。将新模型应用于某矿瓦斯涌出量预测,并对模型的预测结果进行检验分析,结果表明:该模型在结合蛙跳算法的全局寻优特点后预测精度较传统的GM(1,1)模型有明显的提高,适用性更强。     

粒子群优化的RBF瓦斯涌出量预测

瓦斯涌出量是煤矿瓦斯灾害的主要来源,它直接影响煤矿安全生产和经济技术指标。瓦斯涌出量的传统预测方法是将其影响因素线性化后提出的,具有一定的局限性。本文基于群体智能理论,提出了一种基于粒子群算法优化的RBF神经网络瓦斯涌出量预测模型。研究表明RBF神经网络预测精度与网络权值和RBF参数初始值有很大关系,因此本文采用粒子群算法优化RBF网络权值和其他参数,形成PSO-RBF预测模型。该模型通过计算种群粒子的适应度,确定全局最优值,寻找网络参数的最优值。实验结果表明PSO-RBF优于传统的RBF预测模型,训练速度和预测精度显著提高。     

油浸变压器排油注氮装置在500kV变电站的设计与应用

在分析500kV变电站主变压器消防系统的现状,比较3类消防系统优缺点的基础上,详细论述了主变排油注氮装置的结构组成、工作原理、参数计算、控制系统设计以及需要注意的事项等,为下一步排油注氮装置的推广应用打下基础.     

HAZOP结合What-if方法在某延迟焦化装置除焦中的应用

为克服传统危险与可操作性（HAZOP）定性分析方法在复杂操作、间歇作业等过程中使用的局限性,提出在传统HAZOP定性分析方法的基础上结合What-if（故障假设）方法,对人的不安全行为和操作规程不完备所导致的风险后果分析作出补充。详细说明其技术原理、工作流程等使用细节,系统阐述该方法与传统HAZOP定性分析方法的区别,并在某延迟焦化装置的除焦操作的风险分析中应用。经分析,识别出在“给水-泡焦”节点,有“操作规程错误”场景2项,“操作规程不具体”场景1项,不存在“操作人员未按操作规程执行”场景。研究结果表明:本文方法有效且具有较好效果,可以广泛应用于操作规程/作业指导书审查、作业过程隐患排查等方面,帮助企业开展操作层面的风险识别与管理,提升企业的生产安全水平。     

潞安矿区煤层渗透率的各向异性特征实验研究

为了研究原位煤体渗透性的各向异性特征,以山西潞安常村矿3号煤层圆柱试样为对象,利用TCQT-Ⅲ型低渗煤层气相驱替增产试验装置,对煤样进行加载,并以氮气注入压力2.0 MPa的条件下,分析垂直层理和平行层理2个方向的煤体变形和渗透率变化特征。实验结果表明:煤样在加载过程中,平行和垂直层理煤样渗透率均随着有效应力的增大而减小,平行层理方向的渗透率始终大于垂直层理方向,应力加载初期渗透率急剧下降,最后逐渐趋于平缓;径向应变的增加量与渗透率呈正相关性,且平行层理相关性大于垂直层理;沿平行层理方向的裂隙度大于沿垂直层理方向,沿垂直层理方向的应变量大于沿平行层理方向;应变增加量均随有效应力的增加而逐渐减小。研究结果可为煤层井网布置及优化提供参考。     

Nighttime pedestrian fatalities: A comprehensive examination of infrastructure,user, vehicle,and situational factors

Introduction: Pedestrian fatalities in the United States increased 45.5% between 2009 and 2017. More than 85% of those additional pedestrian fatalities occurred at night. Method: We examine Fatality Analysis Reporting System (FARS) data for fatal pedestrian crashes that occurred in the dark between 2002 and 2017. Within-variable and before/after examinations of crashes in terms of infrastructure, user, vehicle, and situational characteristics are performed with one-way analysis of variance (ANOVA) and two-sample t-tests. We model changes in crash characteristic proportions between 2002–2009 and 2010–2017 using linear regressions and test for autocorrelation with Breusch-Godfrey tests. Results: The increase in fatal nighttime pedestrian crashes is most strongly correlated with infrastructure factors: non-intersection unmarked locations (saw 80.8% of additional fatalities); 40–45 mph roads (54.6%); five-lane roads (40.7%); urban (99.7%); and arterials (81.1%). In addition, SUVs were involved in 39.7% of additional fatalities, overrepresenting their share of the fleet. Increased pedestrian alcohol and drug involvement warrant further investigation. The age of pedestrians killed increased more (18.1%) than the national average (3.2%). Conclusions: By identifying factors related to the increase in nighttime pedestrian fatalities, this work constitutes a vital first step in making our streets safer for pedestrians. Practical Applications: More research is needed to understand the efficacy of different solutions, but this paper provides guidance for such future research. Engineering solutions such as road diets or traffic calming may be used to improve identified infrastructure issues by reducing vehicle speeds and road widths. Rethinking vehicle design, especially high front profiles, may improve vehicle issues. However, the problems giving rise to these pedestrian fatalities are likely a result of not only engineering issues but also interrelated social and political factors. Solutions may be correspondingly comprehensive, employing non-linear, systems-based approaches such as Safe Systems.     

Footedness and Mounting—Short Review and Two Case Studies

Footedness is a personal quality like handedness. Footedness may be associated with moving ability during mounting, dismounting, and jumping movements. Occupational accidents have occurred during movement at different working levels, during the use of access and exit systems, and during the mounting of vehicles. Aging can also affect accident risk and body laterality. For example, falling accidents on stairs are common among the elderly. One reason for accidents may be that the structure of the access system or stair system is unsuitable for individual moving patterns depending partly on body laterality. Footedness and the way the feet are used may be contradictory to the demands of the moving situation, especially during uncommon or rapid situations. This contradiction may trigger disturbance during moving. The aims of this pilot study were (a) to review the literature briefly and (b) to describe the use of the dominant and nondominant foot by farmers and the elderly when mounting a tractor and stairs, respectively. The study also gives ideas for future studies based on both (a) and (b).     

AHP与GA-SVM耦合模型在滑坡预警中的应用*

为了减少滑坡造成的损失,提高滑坡预测的准确性,通过搭建灾害模拟平台获得滑坡的实验数据,在获得多组模拟实验数据后,分析各变量的特性。首先,通过层次分析(Analytic Hierarchy Process,AHP)算法,对滑坡进行危险度划分;然后,通过支持向量机(Support Vector Machine,SVM)建立模型,遗传算法(Genetic Algorithm,GA)再优化SVM参数,提出1种层次分析法与GA-SVM相耦合的模型。研究结果表明:AHP方法划分后的数据,通过GA与SVM结合建立的模型精度较好,实验预测结果与实际结果较为吻合,与单一SVM相比,精度更高,结果更好,更加适用于多变量的复杂非线性滑坡预警。     

Debunking the false dichotomy of leadership idealism and pragmatism: Critical evaluation and support of newer genre leadership theories

Leadership theories have shifted over the last few decades from a focus on managerial functions and economic leader–follower exchanges toward greater focus on the interpersonal dynamics occurring within the leadership process. Theories such as transformational, ethical, authentic, and other “newer genre” theories were created to address neglected topics such as leader vision and inspirational messages, transparency, emotional effects, morality, individualized attention, and intellectual stimulation. Critiques of these theories, however, have been raised. In this paper, we address five of those critiques and argue for the validity and practical effectiveness of the new genre theories. Further, we describe how newer genre leadership research should be viewed as a performative epistemology, entailing a process of co‐creation involving scholars and practitioners. Finally, from this view, we provide general ideas for leader development. Copyright © 2014 John Wiley & Sons, Ltd.     

Occupational Safety and Health in Finland

In Finland, occupational safety is the responsibility of the employer, while the occupational safety and health laws are enforced by the Labour Inspection Service, an organization of the state. The Labour Inspection is divided in 11 administrative districts, and it employs 360 professionals. They are mandated to carry out site visits without prearranged appointments to inspect safe work situations, working hours, construction safety, or any aspect of accident risks. The inspectors are also mandated to verify the existence of sufficient occupational health services as prescribed by the Occupational Health Services Act for all employees. The occupational health services are typically provided by enterprise-owned medical departments, by mutually owned health care centers, by private practitioners, or by municipal health care centers. The latter are required by law to provide all services as prescribed by the legislation to anyone who comes to the facility. This situation is prevalent in the countryside, where there are very few private caregiving centers. Declaring occupational accidents and disease cases is mandatory, and the Inspection districts examine all accidents to establish causes and consequences, and to initiate prosecution in case of criminal negligence. Labour Inspection Districts are also notified of the new occupational disease cases as they are declared to insurance companies. Insurance for occupational disease, accidents, and death is an obligation of the employer, although they can choose the insurance company. The medical confidentiality between the workers and their occupational health care providers is very strict. Official statistics are maintained by the state Statistics Finland organization, and they may be used, for example, for research purposes by scientific institutes like the Finnish Institute of Occupational Health. Construction industry accounts for 25% of all fatal accidents (120 cases per 1 million working hours), followed by mechanical, wood, metal, machinery, and pulp and paper industry (10% each of fatal accidents) with rates ranging from 100–160 cases per 1 million working hours. There are some 5,000 occupational disease cases per year (rate 22/10,000 employed). The major disease categories include repetitive strain injuries (1,300 cases), respiratory allergies (600 cases), occupational skin diseases (1,000 cases), and 900 cases of noise-caused hearing loss. In 1998, 589 cases of asbestos-related diseases were reported.     

森林地表火蔓延模拟方法及其计算机实现

进行了森林火蔓延的研究,对传统的经验公式和模型进行改进,明显发现改进的模型有更好的结果,用计算机巧妙准确地实现了模拟模型,在风力不是特别大,地形变化不是特别剧烈时,该模型有较高精度;并结合火蔓延的主要因素（气象因子、气候、地形等）,进行系统分析,写出算地,编制实现地表火蔓延的预测预报计算机系统软件。这对于有效的组织扑救、减少火灾损失、计算森林火灾的损失评估有重要意义。     

公路隧道火灾逃生疏散研究

以苍岭隧道为背景,首先采用经验计算理论和计算软件building EXODUS相结合的方式,从被困人员的安全疏散时间、高温烟气的影响、隧道横通道的利用率以及人员的疏散行为特性进行了研究。结果表明:中小规模火灾情况下的安全疏散时间控制在8 min之内,高温烟气影响不大,但横通道的利用率不平均,且人员疏散路线相对集中。然后对存在的逃生疏散问题提出针对性建议以及其他相关建议,旨在为更大程度降低事故的严重性和经济财产损失。