首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
用WSN对铀尾矿库核素污染监测优于传统有线布置,为解决无线传输路由能耗的问题,提出了一种基于蚁群算法的前向传输分簇路由协议。该协议以分簇的方式来减少数据发送量与寻优开销,在下一跳接收节点选择阶段,以前向传输区域为切入点,利用优化的蚁群算法进行多路径搜索最后选出满足条件的最优路径。仿真实验表明,CFTA协议的网络生存周期有效延长,并减小了能耗。  相似文献   

2.
移动Ad hoc网络路由协议的安全性分析与对策   总被引:5,自引:0,他引:5  
移动Ad hoc网络是一种自组织、多跳的无线网络,由于其独特性能使移动Adhoc网络面临着比现有网络具有更大的安全挑战,其中路由安全对该网络的安全性起着关键性的作用。在介绍移动Ad hoc网络主要路由协议及其特点的基础上,笔者深入研究了移动Ad hoc网络路由协议中存在的黑洞、拒绝服务等安全漏洞;详细分析了几种主要的Ad hoc路由协议的安全性增强方案;根据不同路由协议的特点,分别提出了利用单向散列链改进距离矢量路由协议安全性的两种方案;分析了一种用于改善源路由协议安全性的方案的可行性。最后,指出了移动Ad hoc网络路由协议安全性问题的进一步改进和研究方向。  相似文献   

3.
针对深井巷道无线传感器网络(Wireless Sensor Networks,WSN)安全监测中节点能量消耗不均匀导致网络生命周期较短的问题,在分析低功耗自适应集簇分层型算法(Low Energy Adaptive Clustering Hierarchy,LEACH)、遗传算法(Genetic Algorithm,GA)和禁忌搜索算法(Tabu Search Algorithm,TS)的基础上,提出遗传禁忌搜索的能量均衡深井安全监测WSN分簇路由算法(GTSR-EB),以分簇方式来减少数据发送量与寻优开销,利用优化GA算法和TS算法进行多路径搜索以选出一条能耗均衡、路径传输距离最短的最优路径。仿真实验表明:GTSR-EB算法网络存活周期为LEACH算法的2.17倍、GA算法的1.18倍,GTSR-EB网络能量利用率更高、生存周期更长。  相似文献   

4.
针对现有隧道火灾监测系统无法有效进行火灾预测,提出了一种基于温湿度感知的隧道火灾监测系统。依据火灾发生的必要条件以温湿度感知相结合的方式构建了温湿度感知模块对隧道火灾进行预测,采用Zig Bee物联网技术构建了空气质量监测模块,监测多项隧道内污染物含量。最后搭建了调控模块,依据温湿度感知模块和空气质量监测模块的数据远程调控隧道内机电设备。系统以信息感知层、数据分析层、数据传输层、数据处理层、执行层为构架建立,实现了火灾预测和隧道空气质量调控,提高了监测系统的运行和处理能力。  相似文献   

5.
赵娟  张伯虎  李旭霞 《安防科技》2007,(1):35-36,13
无线传感器网络节点能量消耗是其路由协议设计的重要目标.分簇式的拓扑结构使网络中的节点相对均衡地消耗能量,显著地延长整个网络的生存时间.在大范围的防火区域中安放传感器节点,通过具有明确位置信息的节点采集并向簇头传送,可有效地发现及控制火灾.  相似文献   

6.
为减少工业氨气泄漏造成的环境污染、人员伤害及财产损失,建立适用于工业氨气泄漏的气体扩散高斯模型,提出氨气泄漏源的定位方法,并研制出一套基于Zig Bee无线传感网的氨气泄漏无线监测系统,其主要包括检测节点、网络协调器以及上位机。试验模拟不同浓度下的氨气泄漏定位,实测的相对定位误差约为12%。试验结果表明:通过简化后的气体扩散高斯模型检测空气中的氨气浓度,并对泄漏源定位,结果与实际情况相符,测量精度符合国家标准;增加氨气传感器的数量可降低定位误差,提高救援抢险效率。  相似文献   

7.
针对当前井下众多的传感器类型,给矿井安全监测带来较大管理难度的问题,设计了面向井下安全监测的多传感器数据融合ZigBee系统,阐述了系统组成和系统实现。通过自定义的负载通信协议,将不同类型的传感器数据融合写入ZigBee协议的MAC负载字段,采集节点根据标准ZigBee协议将数据传输至汇聚节点,汇聚节点汇总后传输至嵌入式网关,并可以由嵌入式网关转发至安全监控中心,最终实现井下多类型传感器数据的实时显示。实际运行结果表明,系统可以兼容多个传感器数据进行ZigBee无线传输。  相似文献   

8.
为解决深部矿井无线传感器网络因节点能量受限导致网络生存时间短及由多跳传输引起的“热区”问题,提出1种以分区结构和能量多路径为基础的带状无线传感器网络多簇首路由算法(NPPEC)。算法采用跳数泛洪方式建立带状网络分区结构,将节点分布密度加入主簇首竞选机制中,通过主簇首和副簇首的分工配合,使簇首能量更均衡地消耗;依据路径能耗、节点当前能量及位置计算路径选择概率,并通过控制跳数改善数据传输的实时性。经仿真比较,NPPEC算法网络生存时间约为LEACH算法的1.807 2倍、HEED-EELD算法的1.198 4倍,同时也有效改善了网络“热区”问题,为深部矿井无线传感器网络的构建提供1种更有效的解决方案。  相似文献   

9.
为解决邮轮火灾应急疏散过程中,由于邮轮内部结构复杂、通道狭窄、人流量大导致人员难以短时间安全疏散的问题,应用基于火灾蔓延预测数据的A*算法求解邮轮火灾的人员疏散路径。首先,根据SAFEGUARD项目中的邮轮数据建立二维网络拓扑结构,定义网络中节点的CO体积分数、烟雾可见度和温度3类指标的阈值,并基于火灾发生的地点和程度,模拟火灾动态蔓延的情况,实时判定疏散网络中各个节点的危险状况;然后,结合火灾蔓延的实时数据改进A*算法,并求解人员的最优疏散路径;最后,使用同一邮轮作为模拟人员疏散的场景,模拟邮轮火灾动态蔓延情况下的人员疏散过程,分析人员疏散路径的可行性。结果表明:改进后的A*算法所求路径能成功绕开网络中受火灾影响较大的危险节点,同时疏散规模为700人的时间比使用基本A*算法所求的疏散时间缩短50%。  相似文献   

10.
基于Dijkstra算法的火灾环境下人员疏散仿真方法   总被引:1,自引:1,他引:0  
模拟建筑物内火灾情况下人员安全疏散,提出一种基于Dijkstra算法的人员疏散仿真方法。该方法借鉴网络路由的思想,综合考虑在人员动态疏散过程中发生的通道、路口损坏,人员拥堵等情况,采用RIP选路协议中的DV算法,实时计算最佳逃离路径(最低耗费路径);同时,利用路由转发机制,辅助人员决策疏散方向。  相似文献   

11.
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.  相似文献   

12.
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。  相似文献   

13.
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.  相似文献   

14.
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。  相似文献   

15.
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).  相似文献   

16.
森林地表火蔓延模拟方法及其计算机实现   总被引:6,自引:1,他引:5  
杜飞  候遵泽  刘家琦 《火灾科学》2001,10(4):204-208
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。  相似文献   

17.
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。  相似文献   

18.
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.  相似文献   

19.
Occupational Safety and Health in Finland   总被引:1,自引:0,他引:1  
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.  相似文献   

20.
公路隧道火灾逃生疏散研究   总被引:2,自引:1,他引:1  
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。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号