深度学习技术在火灾图像识别中的应用

火灾事故频发严重威胁着社会公共安全和人们的生命财产安全。火灾发生的不可预见性增加了火灾防控的难度。传统温感、烟感火灾探测设备对室内空间火灾探测效率较高;以人工选择特征为依据的火灾图像识别技术受限于实际火灾场景特征复杂多变,存在误报情况;深度学习技术通过海量火灾场景图片训练和网络参数优化,自动提取火灾图像深度抽象特征,以达到对火灾的精准识别和预警判断。本文就火灾图像识别及深度学习技术在该领域中的应用进行分析,对影响深度学习技术在火灾图像识别应用中的瓶颈问题进行探讨,并展望了该技术的未来发展。     

基于SIR模型的隐蔽信道数据安全检测仿真

隐蔽信道数据分布散乱,对数据检测造成阻碍。针对传统的隐蔽信道数据检测方法存在检测速度慢、有效性差等问题,提出一种基于SIR模型的隐蔽信道数据安全检测方法。构建SIR隐蔽信道模型,使用在线检测模型进行隐蔽信道数据编码处理,使用密度聚类算法对隐蔽信道编码数据进行搜索聚类,划分密度区域,通过判断各密度区域数据有效性,完成隐蔽信道数据的密度聚类。利用决策树对聚类完成的数据进行特征属性提取,引入特征属性获取新的信息递增率,通过数据间差异性计算完成隐蔽信道数据安全检测。实验结果表明,所提方法能有效完成隐蔽信道数据检测,精准度、效率和稳定性均优于传统方法,且检测耗时少,具有显著优势。     

强力输送带纵向防撕裂系统的设计与实现

强力输送带（输送机）广泛应用于钢铁、煤炭、冶金、矿山、港口等领域的物料输送。普通强力输送带存使用中，常因尖锐物料扎入或输送机马力大、速度快，造成纵向大范围撕裂。据不完全统计，全国每年因撕裂报废的输送带价值数亿元，因输送带撕裂造成停产带来的损失就更惊人。研制开发强力输送带纵向防撕裂系统，可以实时检测输送带的状况，一旦发现撕裂立即停机并报警，防止撕裂范围的扩大，避免了因输送带撕裂造成的巨大损失，具有重大的经济效益。强力输送带纵向防撕裂系统是国务院重大攻关项目“大型高强度输送带”的重要课题，已经通过部级鉴定，达到国际同类装置的先进水平，并申请获得两项专利。系统原理先进，性价比高。抗干扰能力强，现场安装方便，并在应用中得到不断的改进与完善．     

点型红外可燃气体探测技术

介绍一种较新的可燃气体探测技术——点型红外可燃气体探测技术,概述了其工作原理(基于气体的光谱本征吸收原理,利用可燃气体吸收特定波段的红外光,通过传感器件接收红外光光通量的物理变化来实现对可燃气体的探测),分析了探测器具体构成(由气体检测单元和信号处理电路单元两部分组成),并给出具体硬件(电源电路、信号放大电路、输出接口电路)设计思路和软件标定算法。     

Reliability analysis with nondestructive inspection

Nondestructive inspection tools are commonly used to inspect structures or structural components with resistance deterioration due to defect size growth. The quality of the tools is mainly defined by the rate of detecting a defect with defect size s, (s), and the accuracy in sizing a detected defect. The uncertainty of sizing a detected defect can be incorporated in limit state functions that include defect size, and a reliability evaluation can be carried out with the efficient first-order reliability method (FORM). The rate of detecting a defect can also be incorporated in the reliability evaluation of an inspected structure or structural component. This is done, in this paper, by introducing a standard normally distributed variate, Z, and defining a limit state function as a function of and (s). Advantages of using this limit state function, rather than using a limit state function based on the actual defect size and the critical defect size distributed according to the rate of detection curve, are discussed. It is shown that one only needs to use the mean rate of defect detection curve to consider the uncertainty in the rate of detection. The incorporation of the uncertainty in rate of detection for reliability updating analysis with inspection results, and for reliability-based selection of optimal inspection and maintenance schedule for resistance deteriorating structures are also presented. The proposed approach is illustrated by two examples in evaluating reliability with inspection information and in selecting an optimal inspection and maintenance schedule by minimizing the probability of time to failure before inspection and before the time at the end of remaining service life.     

A design method for flaming fire detection

The scientific basis of a design method for the detection of flaming fires is reviewed. The equations required to calculate detector spacings are included and the selection of appropriate design input parameters is discussed. Limitations of the method and areas for further research are identified. The design method has been implemented and proposed for inclusion in NFPA Standard 72E-1984 as Appendix C by the 72E-M Committee. Center for Fire Safety Studies Worcester Polytechnic Institute     

Recovery and detection of Cryptosporidium parvum oocysts from water samples using continuous flow centrifugation

Continuous flow centrifugation (CFC) was used in conjunction with immunomagnetic separation (IMS) and immunofluorescence microscopy (IFA) and nested PCR to recover and detect oocysts of Cryptosporidium parvum and cysts of Giardia intestinalis from 10L volumes of source water samples. Using a spiking dose of 100 oocysts, nine of 10 runs were positive by IFA, with a mean recovery of 4.4+/-2.27 oocysts; when another 10 runs were analyzed using nested PCR to the TRAP C-1 and Cp41 genes, nine of 10 were positive with both PCR assays. When the spiking dose was reduced to 10 oocysts in 10L, 10 of 12 runs were positive by IFA, with a mean oocyst recovery of 3.25+/-3.25 oocysts. When 10 cysts of Giardia intestinalis were co-spiked with oocysts into 10L of source water, five of seven runs were positive, with a mean cyst recovery of x=0.85+/-0.7. When 10 oocysts (enumerated using a fluorescence activated cell sorter) were spiked into 10L volumes of tap water, one of 10 runs was positive, with one oocyst detected. For the majority of the source water samples, turbidities of the source water samples ranged from 1.1 to 22 NTU, but exceeded 100 NTU for some samples collected when sediment was disturbed. The turbidities of pellets recovered using CFC and resuspended in 10 mL of water were very high (exceeding 500 NTU for the source water-derived pellets and 100 NTU for the tap water-derived pellets). While not as efficient as existing capsule-filtration based methods (i.e., US EPA methods 1622/1623), CFC and IMS may provide a more rapid and economical alternative for isolation of C. parvum oocysts from highly turbid water samples containing small quantities of oocysts.     

Application of real-time quantitative PCR for the detection of selected bacterial pathogens during municipal wastewater treatment

Bacteria were detected at five stages of municipal wastewater treatment using TaqMan(R) real-time quantitative PCR (qPCR). Thirteen probe and primer sets were tested for diverse pathogens that may be present in wastewater, including Aeromonas hydrophila, Bacillus cereus, Clostridium perfringens, Enterococcus faecalis, Escherichia coli, E. coli O157:H7, Helicobacter pylori, Klebsiella pneumoniae, Legionella pneumophila, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella sp., and Staphylococcus aureus. The sensitivity of the assay was 100 fg of genomic DNA (=22 gene copies), based on a standard curve generated using A. hydrophila purified DNA. Samples from five stages of wastewater treatment were collected, including raw wastewater, primary effluents, mixed liquor, waste activated sludge and final effluents. In duplicate samples, E. coli, K. pneumoniae, C. perfringens and E. faecalis were detected throughout the wastewater process, and their numbers decreased by 3.52-3.98, 4.23-4.33, 3.15-3.39, and 3.24 orders of magnitude respectively, between the raw wastewater and final effluent stage. This qPCR method was effective for the detection of pathogens in wastewater and confirmed that the risk of exposure to pathogens in the wastewater discharge was well within the Environment Canada guidelines.     

探地雷达在城市道路检测中的典型工程实例剖析

城市道路地下空洞及缺陷是威胁城市交通安全的重要风险源,一直是城市交通工程安全难以攻克的课题。随着城市道路管理的地理信息化,结合有效的检测手段和方法,及时掌握道路地下空洞和土层的密实、松散信息,对于城市道路安全具有非常重要的意义。目前,探地雷达技术在我国广泛应用于道路的无损探测中,而且取得了较好的检测效果。本文论述了一个关于探地雷达技术在长安街道路探测中的典型应用范例。     

Surface-effect on detection ability of fluorescent Eu(btc) metal-organic frameworks to metal ions

Eu(btc)metal organic frameworks(MOFs)were prepared by co-precipitation method via 1,2,4-benzenetricarboxylic acids(H3btc)connecting with Eu³⁺ions,and the morphology was controlled from compact spherical to irregular honeycomb by adjusting the pH of reaction solutions.The luminescence properties of Eu(btc)MOFs are found to be related to the surface morphology of products,and the compact spherical one performs stronger emission intensity.The sensing ability of Eu(btc)MOFs to 11 kinds of metal ions was investigated and a prominent quenching effect occurrs in Fe³⁺,or Ni²⁺solutions.Based on UV—vis absorption analysis,an“ion-fence”model presents the competition to absorb exciting light between Eu(btc)MOFs and adsorbed metal ions.Based on Stern-Volmer equation,the Eu(btc)detection is found with higher Ksv value and a lower detection limit.Meanwhile,a higher sensing efficiency is confirmed in the Eu(btc)MOFs with loose honeycomb due to aggravating porous surface offering much more sites for metal ions.