Sequential Pattern Technology for Visual Fire Detection

Visual fire detection technologies can detect fire and alarm warnings earlier than conventional fire detectors. This study proposes an effective visual fire detection method that combines the statistical fire color model and sequential pattern mining technology to detect fire in an image. Furthermore, the proposed method also supports real-time fire detection by integrating adaptive background subtraction technologies. Experimental results show that the proposed method can effectively detect fire in test images and videos. The detection accuracy of the proposed hybrid method is better than that of Celik＇s method.

Dynamics of firing patterns,synchronization and resonances in neuronal electrical activities:experiments and analysis

Recent advances in the experimental and theoretical study of dynamics of neuronal electrical firing activities are reviewed. Firstly, some experimental phenomena of neuronal irregular firing patterns, especially chaotic and stochastic firing patterns, are presented, and practical nonlinear time analysis methods are introduced to distinguish deterministic and stochastic mechanism in time series. Secondly, the dynamics of electrical firing activities in a single neuron is concerned, namely, fast-slow dynamics analysis for classification and mechanism of various bursting patterns, one- or two-parameter bifurcation analysis for transitions of firing patterns, and stochastic dynamics of firing activities （stochastic and coherence resonances, integer multiple and other firing patterns induced by noise, etc.）. Thirdly, different types of synchronization of coupled neurons with electrical and chemical synapses are discussed. As noise and time delay are inevitable in nervous systems, it is found that noise and time delay may induce or enhance synchronization and change firing patterns of coupled neurons. Noise-induced resonance and spatiotemporal patterns in coupled neuronal networks are also demonstrated. Finally, some prospects are presented for future research. In consequence, the idea and methods of nonlinear dynamics are of great significance in exploration of dynamic processes and physiological functions of nervous systems.

Responses from two firing patterns in inferior colliculus neurons to stimulation of the lateral lemniscus dorsal nucleus

The γ-aminobutyric acid neurons（GABAergic neurons） in the inferior colliculus are classified into various patterns based on their intrinsic electrical properties to a constant current injection. Although this classification is associated with physiological function, the exact role for neurons with various firing patterns in acoustic processing remains poorly understood. In the present study, we analyzed characteristics of inferior colliculus neurons in vitro, and recorded responses to stimulation of the dorsal nucleus of the lateral lemniscus using the wholecell patch clamp technique. Seven inferior colliculus neurons were tested and were classified into two firing patterns： sustained-regular（n = 4） and sustained-adapting firing patterns（n = 3）. The majority of inferior colliculus neurons exhibited slight changes in response to stimulation and bicuculline. The responses of one neuron with a sustained-adapting firing pattern were suppressed after stimulation, but recovered to normal levels following application of the γ-aminobutyric acid receptor antagonist. One neuron with a sustained-regular pattern showed suppressed stimulation responses, which were not affected by bicuculline. Results suggest that GABAergic neurons in the inferior colliculus exhibit sustained-regular or sustained-adapting firing patterns. Additionally, GABAergic projections from the dorsal nucleus of the lateral lemniscus to the inferior colliculus are associated with sound localization. The different neuronal responses of various firing patterns suggest a role in sound localization. A better understanding of these mechanisms and functions will provide better clinical treatment paradigms for hearing deficiencies.

A comparison of the spontaneous firing patterns between principal cells and fast spiking interneurons from dentate gyrus in waking guinea pigs

Objective To explore the possible mechanisms that cause the dentate gyrus （DG） neurons to play different roles in information coding. Methods In vivo extracellular single unit recording was performed on 22 waking female guinea pigs, which were positioned in a sound-attenuated recording chamber without any muscular relaxants. The spontaneous firing patterns of the DG neurons were detected and compared. Results There were two different electrophysiologi- cal populations in the DG of guinea pigs, principal cells （PCs） and fast spiking interneurons （INs）. Of the PCs, 1.3% discharged regularly, 48.1% irregularly and 50.6% in bursts ; in contrast, of the INs units, 64.1% discharged regularly, 2.6% irregularly and 33.3% in bursts. The spontaneous firing patterns of PCs were significantly different from those of INs （P 〈0.01 ）. In addition, the differences of several interspike interval （ISI） parameters also have been observed： （1） the ISI coefficients of variation of PCs （3.39 ± 3.56） were significantly higher than those of INs （1.08 ± 0.46） （P 〈0.01） ; （2） the ISI asymmetric indexes of PCs （0. 047±0. 059） were significantly lower than those of INs （0.569±0. 238） （P 〈 0.01 ）. Conclusion In the DG, the spontaneous firing patterns of PCs were significantly different from those of INs. The former were prone to fire in bursts, the latter were prone to fire regularly. The different roles in information coding between PCs and INs might be caused by their different firing patterns.

Spiking patterns of a hippocampus model in electric fields

We develop a model of CA3 neurons embedded in a resistive array to mimic the effects of electric fields from a new perspective. Effects of DC and sinusoidal electric fields on firing patterns in CA3 neurons are investigated in this study. The firing patterns can be switched from no firing pattern to burst or from burst to fast periodic firing pattern with the increase of DC electric field intensity. It is also found that the firing activities are sensitive to the frequency and amplitude of the sinusoidal electric field. Different phase-locking states and chaotic firing regions are observed in the parameter space of frequency and amplitude. These findings are qualitatively in accordance with the results of relevant experimental and numerical studies. It is implied that the external or endogenous electric field can modulate the neural code in the brain. Furthermore, it is helpful to develop control strategies based on electric fields to control neural diseases such as epilepsy.

基于AVL-FIRE的SAI发动机缸内流场仿真

针对通用汽油机的充气技术,提出缸侧辅助充气(SAI,Side Air Injection)方法,通过优化缸内气流在中小负荷实现分层稀薄燃烧.以168F通用汽油机为原型,使用AVL-BOOST计算出初始条件,再运用AVL-FIRE仿真分析在不同辅助充气压力下SAI发动机对缸内速度场、湍动能和当量比的影响.分析表明:SAI发动机可在火花塞周围形成尺度大涡流强的分层混合气,可提高燃烧速率,改善汽油机稀薄燃烧着火稳定性.

Dynamics analysis on neural firing patterns by symbolic approach

Neural firing patterns are investigated by using symbolic dynamics. Bifurcation behaviour of the Hindmarsh-Rose （HR） neuronal model is simulated with the external stimuli gradually decreasing, and various firing activities with different topological structures are orderly numbered. Through constructing first-return maps of interspike intervals, all firing patterns are described and identified by symbolic expressions. On the basis of ordering rules of symbolic sequences, the corresponding relation between parameters and firing patterns is established, which will be helpful for encoding neural information. Moreover, using the operation rule of ＊ product, generation mechanisms and intrinsic configurations of periodic patterns can be distinguished in detail. Results show that the symbolic approach is a powerful tool to study neural firing activities. In particular, such a coarse-grained way can be generalized in neural electropt/ysiological experiments to extract much valuable information from complicated experimental data.

Forest Fire Smoke Detection Method Based on MoAm-YOLOv4 Algorithm

To improve the performance of the forest fire smoke detection model and achieve a better balance between detection accuracy and speed, an improved YOLOv4 detection model (MoAm-YOLOv4) that combines a lightweight network and attention mechanism was proposed. Based on the YOLOv4 algorithm, the backbone network CSPDarknet53 was replaced with a lightweight network MobilenetV1 to reduce the model’s size. An attention mechanism was added to the three channels before the output to increase its ability to extract forest fire smoke effectively. The algorithm used the K-means clustering algorithm to cluster the smoke dataset, and obtained candidate frames that were close to the smoke images;the dataset was expanded to 2000 images by the random flip expansion method to avoid overfitting in training. The experimental results show that the improved YOLOv4 algorithm has excellent detection effect. Its mAP can reach 93.45%, precision can get 93.28%, and the model size is only 45.58 MB. Compared with YOLOv4 algorithm, MoAm-YOLOv4 improves the accuracy by 1.3% and reduces the model size by 80% while sacrificing only 0.27% mAP, showing reasonable practicability.

不同空间尺度的内蒙古森林火点及面积分布格局研究

通过选用空间变异性分析(变异系数)、全局空间自相关分析、热点分析和尺度方差分析等方法,研究1981—2020年内蒙古森林火点及面积在盟市和旗县2个空间尺度上分布的变异性、关联性及尺度效应。结果表明:盟市尺度林火面积变异系数总体呈上升趋势;旗县尺度林火面积变异系数总体呈下降趋势,旗县尺度空间变异性更大。40 a全局森林火点Moran's I指数为0.99,双空间尺度Moran's I指数均呈下降趋势。其中,盟市级别最大值在1991—1995年,为0.46;旗县级别最大值在1986—1990年,为0.61。双尺度森林火点在空间上均呈现高度聚集性。旗县级尺度更显著地展示了森林火灾的空间分布差异及较小区域的森林火灾热点类型;盟市级尺度揭示了森林火灾的总体空间分布规律,热点类型明显缺乏多样性。盟市尺度热点区主要分布在呼伦贝尔市、兴安盟,冷点区不明显。旗县尺度均存在热点聚集区,林火发生水平较高。不同空间尺度的尺度方差表现为旗县>盟市,旗县级尺度林火面积差异对全内蒙古自治区的总体差异贡献率远超过盟市尺度。1981—2020年林火面积在双空间尺度呈现一定的分布规律,火点空间聚集性呈减弱趋势,森林火点与林火面积之间不完全呈正相关关系。内蒙古东部地区由于自然因素和人为因素造成火灾发生次数高于中西部,相关部门应继续加大防火力度。随着尺度的减小,林火空间分布模式愈加明显、聚集度增强,未来需进一步缩小研究范围。

内蒙古大兴安岭3种主要火源引发森林火灾次数和面积的时空分布特征

以内蒙古大兴安岭1981—2020年森林火灾资料为基础,分别分析3种火源的时间变化特征;通过MK突变检验进行趋势分析;使用多距离空间聚类分析与核密度分析方法分析3种火源的空间分布格局。结果表明:内蒙古大兴安岭1981—2020年间雷击火的辐射范围最广,吸烟火与农事用火相对集中;3种火源(除雷击火频次在增加)的发生频次与危害均在减小;雷击火高发于夏季,以5—7月最为活跃,且在00:00—0:59发生次数最多,04:00—4:59危害最大,吸烟火与农事用火高发于春季,以4—5月份最为活跃,且在08:00—19:59期间多发频发并具有一定危害性;雷击火重点防范地区为北部原始林区、满归、阿龙山、莫尔道嘎、根河、甘河、克一河、伊图里河林业局,吸烟火与农事用火的重点防范地区为大杨树和毕拉河林业局。随着内蒙古大兴安岭火源管控、林火监测和扑救能力的逐渐加强,致使3种火源在近年来造成的火场总面积都有大幅度下降;3种火源引发的森林火灾多发生于春季和夏季,引发的森林火灾在空间上都呈显著聚集分布。

Forest Fires and Climate Correlation in Mexico State: A Report Based on MODIS

Forest fires are one of the most important threats for forests in the State of Mexico. Therefore, understanding their geographical patterns is a priority for the design of forest management strategies. We processed the records obtained with the MOD14A2 product (for thermal anomalies and fire) of MODIS sensor. Such scenes correspond to dry seasons (from March 15 to June 30) from 2000 to 2012 in the State of Mexico. We analyzed such records in a GIS environment to learn their spatial patterns and establish their geographical correlations as a first step to understand the causal agents of forest fires. As a result, forest fires in the State of Mexico showed a clustered spatial trend with a southwest tendency and a slight spatial relation with total winter precipitation and maximal temperature in summer.

喷射火作用下石化装置热响应规律数值模拟研究

为探究风速、风向、喷射口径对喷射火作用下石化装置温升规律的影响,采用火灾动力学模拟(FDS)软件对喷射火作用下石化装置温升规律开展了系统的数值模拟研究。结果表明喷射口径小于0.15 m时,装置的温升速率随喷射口径的增大增速较快,喷射口径大于0.2 m时,装置的温升速率随喷射口径的增大增速减缓,石化装置的温升速率与喷射口径呈指数函数关系。风速和风向都会对石化装置的峰值温度和温升速率产生较大的影响,石化装置的温升速率随风速增大呈现一元三次函数的关系。风速增大时,装置峰值温度逐渐降低且降幅逐渐增大,风向与火焰夹角增大时,石化装置的峰值温度逐渐降低且降幅逐渐较小。研究建立了喷射火作用下石化装置温升定量计算公式,实现石化装置温度随喷射火作用时间变化的定量计算,可为安全管理与事故应急管理提供数据支撑。

全国名中医王檀从“心神失控”论治肺癌经验

介绍王檀治疗肺癌临证经验。王檀认为“异生”是肿瘤发生、发展的核心,提出“肺异生物”中医病名,病机关键为“心神失控、肺气不足、相火司令”,治疗基本原则为“养心调神、补益肺气、制约肝火”,形成纠正“异生状态”、改善“异生环境”和削减“异生物生长”三位一体的治疗模式。

基于调和阴阳理论针灸组方治疗老年肝郁化火型失眠

目的探讨基于调和阴阳理论针灸组方治疗老年肝郁化火型失眠的临床疗效。方法将老年肝郁化火型失眠患者80例按照随机数表法分为对照组与观察组,各40例。对照组采用西药治疗,观察组在对照组基础上联合调和阴阳法针灸治疗。观察2组治疗前后中医证候积分、多导睡眠图、匹兹堡睡眠质量指数量表(PSQI)、失眠严重程度指数量表(ISI)、爱普沃斯嗜睡量表(ESS)、血清单胺递质指标5-羟色胺(5-HT)、谷氨酸(GA)、神经肽Y(NPY)、γ-氨基丁酸(GABA)变化,并评价2组治疗总有效率和治疗安全性。结果观察组治疗后各项中医证候积分、睡眠潜伏期、觉醒时间、PSQI评分、ISI评分、ESS评分均低于对照组(P<0.05),睡眠总时间、快速眼动睡眠期、5-HT、GA、NPY、GABA指标均高于对照组(P<0.05);观察组治疗总有效率(92.5%,37/40)高于对照组(77.5%,31/40)(P<0.05);2组不良反应发生情况比较,差异无统计学意义(P>0.05)。结论基于调和阴阳理论的针灸组方联合西药治疗老年肝郁化火型失眠疗效明显,能够缓解患者不适症状,减轻日间嗜睡程度,调节神经递质表达,改善睡眠质量,且不良反应少。

火灾下双钢板-混凝土组合墙抗冲击机理分析与挠度预测

双钢板-混凝土组合墙(steel-concrete composite wall,SC wall)常用于核电站、超高层等重要结构的承重构件,其在偶然荷载作用下的力学性能也是其推广应用的关键指标。为此,针对火灾下SC墙的抗冲击性能进行研究并给出相关设计建议。首先建立了SC墙在火灾与冲击耦合作用下的有限元模型,在验证模型可靠性基础上,开展了火灾下SC墙抗冲击机理的分析;然后研究了轴力、受火时间、材料强度、冲击能量与抗剪连接件形式等参数对SC墙在火灾下抗冲击性能的影响规律;最后给出了该类构件在耦合工况下跨中峰值挠度的预测公式。结果表明:随着受火时间的增加,SC墙受冲击变形模式由局部冲切逐渐转变为整体弯曲破坏;火灾下,混凝土为SC墙受冲击的主要耗能部件;混凝土强度、轴力与抗剪连接件形式对SC墙在高温下的抗冲击性能影响显著,钢板强度的影响则较小;建议的公式可较合理地预测火灾下SC墙受冲击后的跨中峰值挠度。

烧成温度对建窑黄兔毫釉纹路的影响

以建阳当地原料红土、建瓯石、草木灰等为主要原料,制备了一种蓝底黄毫的兔毫釉。通过XRD、Raman、SEM、EDS等测试方法,探究烧成温度对建窑黄兔毫釉毫纹的影响规律及作用机理。实验结果表明:兔毫釉烧成温度范围较窄,在较低温度1270~1290℃下,釉中主要是分相-析晶,毫纹处ε-Fe_(2)O_(3)晶体尺寸为150 nm,釉中由于高温液相黏度较大晶体无法迁移形成釉面斑点;随着烧成温度升高至1310℃,釉面出现毫纹,釉浆黏度逐渐减小,釉中结构完成分相向析晶的转变,毫纹中的ε-Fe_(2)O_(3)晶粒数量增加,尺寸为300 nm,底釉中的晶核逐渐向毫纹中迁移,导致1350℃以上釉面逐渐呈现密集的黄色毫纹。在1330℃的兔毫釉釉浆黏度适中,底釉略微泛蓝,毫纹形态为细长的拉丝状,清晰分明,效果较佳。

新西兰森林火历史研究对我国西南林区火管理的启示

新西兰森林火历史展示了不同阶段的森林燃烧模式,主要包括人类到达前、毛利人时期、欧洲人时期以及近代的森林燃烧模式。在森林状况和林火管理政策等因素影响下,森林火灾模式表现出不同的规律。在林火历史阶段中,新西兰的植物分布特征与我国西南林区具有一定相似性,因此,借鉴新西兰成熟的林火管理经验有利于我国西南林区火历史研究,合理把握西南林区火动态规律,为我国西南林区未来调整和修订林火管理政策和森林防火方针等提供参考。

基于设计符号学的云南彝族“火”图案语义重构路径研究

当下以云南彝族“火”图案为代表的民族性图案呈现多元化发展趋势,社会发展因素与图案主体之间相互作用影响,但同时它的发展也面临着问题。基于此引入设计符号学的相关理论,分析“火”图案符号化的形成、语义维度、语义重构和对现代传统手工艺的启示,以“视觉呈现—维度表达—打散重构—启示创新”为关键点,从语义维度对“火”图案进行重构,将民族传统文化符号转变为易感知、可接受的载体形式,从浅层、中层和深层提出重构方案,构建新发展模式。重塑“火”图案在当代社会中的价值,用传承和再造的方式,实现“火”图案的传承和发展,最终用符号化的设计思维和设计方法为当代传统手工艺的研究提供思路与方法。

广西南丹县2001-2020年森林火灾的时空特征及其与地形和气象因子的相关性

为深入了解森林火灾发生的时空分布格局及影响因素,优化防火和灭火资源的合理配置,采用时间序列法对广西南丹县2001-2020年森林火灾的变化特征进行分析,比较不同森林类型的受损特征与火因构成,并分析森林火灾与地形和气象因子之间的相关性。结果表明:(1)南丹县较大森林火灾发生在2001-2008年,而一般森林火灾发生在2009-2020年。全县80%的森林火灾发生在每年的1-4月,且主要集中于县域范围从西北到东南的中间地带,为交通路网密集或人口聚集区。(2)对于不同森林类型,灌木林和荒山更易发生森林火灾,而马尾松林、杉木林和桉树林虽然发生火灾次数较少,但受损面积远高于灌木林和荒山。人为因素如生产性用火和非生产性用火是导致森林火灾的主要原因。(3)森林火灾受到地形特征以及海拔因素的综合影响,即使在火灾频率较低的地方,火灾发生后如未能得到有效控制,其扩散蔓延的范围也较大。(4)虽然南丹县森林火灾次数和火场面积与主要气象指标的相关性较弱,但因子分析结果表明,各年份起主导作用的气象因子不同是森林火灾产生年际差异的主要原因。因此,未来南丹县应当依据当地森林火灾时空特征和准确掌握气候变化,加大林火监测和管理力度以预防森林火灾的发生,并制定科学的林火管理和扑救策略以更好地应对森林火灾。

基于正交试验和FDS的狭小面积高空间火灾烟气扩散规律研究

为提高狭小面积高空间场所的排烟效率,采用正交试验和火灾动力学模拟工具(FDS),对49组工况下的狭小面积高空间场所进行火灾模拟,研究其火灾危险性和烟气扩散规律。结果表明:场所面积和火源位置是影响火灾危险性的主要因素;烟气高度评价指标在评估火灾风险性时更敏感,应优先考虑;在相同时间下,场所面积为50 m^(2)的烟气高度明显低于200 m^(2);在进行狭小面积高空间场所的烟气扩散规律研究时,需综合考虑场所的功能和可燃物情况等因素。研究结果可为类似场所排烟系统优化设计提供参考。