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预动式交通路口的红绿灯优化设计思路——一种智能的红绿灯信号控制方法
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作者 黄海波 曹利坤 王学军 《广东公安科技》 2022年第3期53-55,共3页
传统的交通信号灯控制,大部分是根据路口的人流与车流的流量,通过调整红灯与绿灯的时间周期,即信号灯配时优化来提高通行效率。本文分析预动式(提前启动)红绿灯控制方法的可行性,理论上可以将信号灯的绿信比提高到100%以上,从而提高交... 传统的交通信号灯控制,大部分是根据路口的人流与车流的流量,通过调整红灯与绿灯的时间周期,即信号灯配时优化来提高通行效率。本文分析预动式(提前启动)红绿灯控制方法的可行性,理论上可以将信号灯的绿信比提高到100%以上,从而提高交通路口的通行效率。 展开更多
关键词 交通流量 信号灯配时 绿信比 预动式
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基于镜像层关联的Docker注册表缓存预取策略
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作者 张晨 邓玉辉 《计算机科学与探索》 CSCD 北大核心 2021年第2期249-260,共12页
随着容器技术的广泛普及,大型Docker公共注册表使用对象存储服务来解决镜像数量剧增的问题,但这种松耦合的注册表设计导致较高的延迟开销。为了增强注册表性能,提出一种基于镜像层关联的Docker注册表缓存预取策略LCPA,当注册表服务器缓... 随着容器技术的广泛普及,大型Docker公共注册表使用对象存储服务来解决镜像数量剧增的问题,但这种松耦合的注册表设计导致较高的延迟开销。为了增强注册表性能,提出一种基于镜像层关联的Docker注册表缓存预取策略LCPA,当注册表服务器缓存未命中时,通过分析镜像元数据文件构建镜像的存储结构,由关联度模型对存储结构计算得到相关镜像层集合,并从后端存储中主动式预取回注册表中以提高缓存命中率。经真实工作负载下收集的Docker数据集测试,实验结果表明LCPA策略比LRU、LIRS和GDFS等缓存算法提高12%~29%的平均缓存命中率,拉取镜像的平均延迟节省率提高了21.1%~49.4%。与现有的LPA预取算法相比,拉取镜像的平均缓存命中率提升25.6%。仿真实验表明该策略可以有效地利用缓存空间,大幅提升注册表的缓存命中率,并降低镜像拉取的延迟开销。 展开更多
关键词 公共注册表 关联度模型 缓存命中率 动式
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A Simple Prediction Formula of Roll Damping of Conventional Cargo Ships on the Basis of Ikeda's Method and Its Limitation 被引量:2
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作者 Yuki Kawahara Kazuya Maekawa Yoshiho Ikeda 《Journal of Shipping and Ocean Engineering》 2012年第4期201-210,共10页
Since the roll damping of ships has significant effects of viscosity, it is difficult to calculate it theoretically. Therefore, experimental results or some prediction methods are used to get the roll damping in desig... Since the roll damping of ships has significant effects of viscosity, it is difficult to calculate it theoretically. Therefore, experimental results or some prediction methods are used to get the roll damping in design stage of ships. Among some prediction methods, Ikeda's one is widely used in many ship motion computer programs. Using the method, the roll damping of various ship hulls with various bilge keels can be calculated to investigate its characteristics. To calculate the roll damping of each ship, detailed data of the ship are needed to input. Therefore, a simpler prediction method is expected in primary design stage. Such a simple method must be useful to validate the results obtained by a computer code to predict it on the basis of Ikeda's method, too. On the basis of the predicted roll damping by Ikeda's method for various ships, a very simple prediction formula of the roll damping of ships is deduced in the present paper. Ship hull forms are systematically changed by changing length, beam, draft, mid-ship sectional coefficient and prismatic coefficient. It is found, however, that this simple formula can not be used for ships that have high position of the center of gravity. A modified method to improve accuracy for such ships is proposed. 展开更多
关键词 Roll damping simple prediction formula wave component eddy component bilge keel component.
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Prediction and optimization of aerodynamic noise in an automotive air conditioning centrifugal fan 被引量:12
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作者 杨振东 谷正气 +2 位作者 汪怡平 颜建容 杨晓涛 《Journal of Central South University》 SCIE EI CAS 2013年第5期1245-1253,共9页
The high aerodynamic noise induced by automotive air conditioning systems has important effects on the ride comfort, and the centrifugal fan is the largest noise source in these systems. It is very important to reduce... The high aerodynamic noise induced by automotive air conditioning systems has important effects on the ride comfort, and the centrifugal fan is the largest noise source in these systems. It is very important to reduce the aerodynamic noise generated by the centrifugal fan. The flow field and the sound field on the whole centrifugal fan configuration have been carried out using the computational fluid dynamics. Simulation results show that the sound pressure level near the outlet of the centrifugal fan is too high. Based on the relationship between flow characteristics and the aerodynamic noise, four parameters of the centrifugal fan, i.e., impeller blade's outlet angle 0, volute tongue's gap t, collector inclination angle fl, and rotating speed n, were selected as design variables and optimized using response surface methodology. While keeping the function of flow rate unchanged, the peak noise level is reduced by 8 dB or 10.8%. The noise level is satisfactorily reduced. 展开更多
关键词 aerodynamic noise multi-forward-curved-blade centrifugal fan OPTIMIZATION response surface methodology
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Recent Study of Drag Embedment Plate Anchors in China 被引量:7
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作者 Haixiao Liu 《Journal of Marine Science and Application》 2012年第4期393-401,共9页
Experimental and theoretical studies of drag embedment plate anchors recently carried out in Tianjin University are summarized in this research paper, which involve a series of important topics relevant to the study o... Experimental and theoretical studies of drag embedment plate anchors recently carried out in Tianjin University are summarized in this research paper, which involve a series of important topics relevant to the study of drag anchors. The techniques for measuring the trajectory and movement direction of drag anchors in soils, the techniques for measuring the moving embedment point and reverse eatenary shape of the embedded drag line, the penetration mechanism and kinematic behavior of drag anchors, the ultimate embedment depth of drag anchors, the movement direction of the anchor with an arbitrary fluke section, the reverse catenary properties of the embedded drag line, the interaetional properties between drag anchor and installation line, the kinematic model of drag anchors in seabed soils, and the analytical method for predicting the anchor trajectory in soils will all be examined. The present work remarkably reduces the uncertainties in design and analysis of drag embedment plate anchors, and is beneficial to improving the application of this new type of drag anchor in offshore engineering. 展开更多
关键词 drag embedment plate anchor vertically loaded plate anchor VLA drag-in plate anchor drag anchor ultimate embedment depth movement direction kinematic model penetration mechanism kinematic behavior
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Prediction of the Mooring Force of a 2-D Floating Oil Storage Tank 被引量:4
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作者 CHU Xinjie DONG Sheng ZHAO Xizeng 《Journal of Ocean University of China》 SCIE CAS 2014年第6期901-910,共10页
A Constrained Interpolation Profile (CIP)-based model is developed to predict the mooring force of a two-dimensional floating oil storage tank under wave conditions, which is validated against to a newly performed e... A Constrained Interpolation Profile (CIP)-based model is developed to predict the mooring force of a two-dimensional floating oil storage tank under wave conditions, which is validated against to a newly performed experiment. In the experiment, a box-shaped floating oil storage apparatus is used. Computations are performed by an improved CIP-based Cartesian grid model, in which the THINC/SW scheme (THINC: tangent of hyperbola for interface capturing; SW: Slope Weighting), is used for interface capturing. A multiphase flow solver is adopted to treat the water-air-body interactions. The Immersed Boundary Method (IBM) is implemented to treat the body surface. Main attention is paid to the sum force of mooring line and velocity field around the body. It is found that the sum force of the mooring line increases with increasing wave amplitude. The body suffers from water wave impact and large body motions occur near the free surface. The vortex occurs near the sharp edge, i.e., the sharp bottom comers of the float- ing oil storage tank and the vortex shedding can be captured by the present numerical model. The present model could be further improved by including turbulence model which is currently under development. Comparison between the computational mooring forces and the measured mooring forces is presented with a reasonable agreement. The developed numerical model can predict the mooring line forces very well. 展开更多
关键词 floating oil storage mooring line force CIP method numerical method Immersed Boundary Method
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Assessment of the Risk of Violence in Portuguese Psychiatric Settings Using the Broset Violence Checklist
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作者 Maria Isabel Marques Aida Bessa +2 位作者 Licinia Santos Sara Carvalho Goreti Neves 《Sociology Study》 2015年第5期360-370,共11页
The risk of violence in psychiatric settings implies the assessment of dynamic predictors to adjust nursing interventions. So as to identify the pattern of aggressive behaviors, assess the dynamic predictors of violen... The risk of violence in psychiatric settings implies the assessment of dynamic predictors to adjust nursing interventions. So as to identify the pattern of aggressive behaviors, assess the dynamic predictors of violence in hospitalized patients, and analyze the predictive qualities of the Brcset Violence Checklist (BVC), an exploratory/descriptive study was conducted in psychiatric wards in Coimbra, Portugal. The instruments used were: the staff observation aggression scale-revised (SOAS-R), visual analogue scale (VAS), and the BVC. For the period of a month, 64 patients with a mean age of 29 years, unemployed, and with psychotic disorders were observed. In this group, 13 people displayed 15 aggressive behaviors of moderate severity, which had consequences for nurses; they were triggered by the denial of something through verbal aggression and controlled by non-restrictive measures. The most common predictors of violence were irritability and boisterousness. It was also concluded that the BVC shows good predictive characteristics (sensitivity and specificity) of violence, thus, it may be considered as a useful and effective instrument to assess the risk of violence and, consequently, to adjust nursing interventions to prevent this phenomenon. 展开更多
关键词 Risk assessment VIOLENCE patients PSYCHIATRY
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Smart Prediction for Seamless Mobility in F-HMIPv6 Based on Location Based Services
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作者 rawya rizk heba nashaat 《China Communications》 SCIE CSCD 2018年第4期192-209,共18页
This paper proposed a new scheme for smooth handoff over F-HMIPv6 networks based on Location Based Services(LBS). It uses the available information about mobile node(MN) such as user mobility patterns and MN's vel... This paper proposed a new scheme for smooth handoff over F-HMIPv6 networks based on Location Based Services(LBS). It uses the available information about mobile node(MN) such as user mobility patterns and MN's velocity to reduce handoff latency. In the proposed scheme, the movement pattern of users plays an important role in the performance analysis. The proposed scheme develops LBS that records a number of mobility patterns based on user daily behavior, and exploits these information to reduce the handoff latency. The proposed scheme is analyzed and compared with F-HMIPv6 protocol. The results show that it improves the performance in terms of handoff latency, packet delivery cost, and location update cost. Specifically, the proposed scheme achieves the tradeoff between realizing a smooth handoff and minimizing the cost that is the demand for all customers of mobile services. 展开更多
关键词 Cost functions F-HMIPV6 loca-tion based services macro handoff mobilitymanagement mobility prediction.
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Immersible ergocycle prescription as a function of relative exercise intensity
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作者 Mauricio Garzon Mathieu Gayda +2 位作者 Anil Nigam Alain-Steve Comtois Martin Juneau 《Journal of Sport and Health Science》 SCIE 2017年第2期219-224,共6页
Purpose: The purpose of this study was to establish the relationship between various expressions of relative exercise intensity percentage of maximal oxygen uptake(%VO_(2max)), percentage of maximal heart rate(%HR_(ma... Purpose: The purpose of this study was to establish the relationship between various expressions of relative exercise intensity percentage of maximal oxygen uptake(%VO_(2max)), percentage of maximal heart rate(%HR_(max)), %VO_2 reserve(%VO_2R), and %HR reserve(%HRR)) in order to obtain the more appropriate method for exercise intensity prescription when using an immersible ergocycle(IE) and to propose a prediction equation to estimate oxygen consumption(VO_2) based on IE pedaling rate(rpm) for an individualized exercise training prescription.Methods: Thirty-three healthy participants performed incremental exercise tests on IE and dryland ergocycle(DE) at equal external power output(Pext). Exercise on IE began at 40 rpm and was increased by 10 rpm until exhaustion. Exercise on DE began with an initial load of 25 W and increased by 25 W/min until exhaustion. VO_2 was measured with a portable gas analyzer(COSMED K4b^2) during both incremental tests. On IE and DE, %VO_2R, %HRmax, and %HRR at equal Pext did not differ(p > 0.05).Results: The %HRR vs. %VO_2R regression for both IE and DE did not differ from the identity line %VO_2R IE = 0.99 × HRR IE(%) + 0.01(r^2= 0.91, SEE = 11%); %VO_2R DE = 0.94 × HRR DE(%) + 0.01(r^2= 0.94, SEE = 8%). Similar mean values for %HRmax, %VO_2R, and %HRR at equal Pext were observed on IE and DE. Predicted VO_2 obtained according to rpm on IE is represented by: VO_2(L/min) = 0.000542 × rpm2-0.026 × rpm + 0.739(r = 0.91, SEE = 0.319 L/min).Conclusion: The %HRR–%VO_2R relationship appears to be the most accurate for exercise training prescription on IE. This study offers new tools to better prescribe, control, and individualize exercise intensity on IE. 展开更多
关键词 Exercise prescription Heart rate Immersed ergocycle Oxygen uptake Pedaling rate
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Alternate Form of Damped Wave Conduction and Relaxation Equation a Capite Adcalcem in Temperature
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作者 Kal Renganathan Sharma 《Journal of Physical Science and Application》 2013年第1期46-53,共8页
An alternate non-Fourier heat conduction equation is derived from consideration of translation motion of spinless electron under a driving force due to an applied temperature gradient. This equation is a eapite ad cal... An alternate non-Fourier heat conduction equation is derived from consideration of translation motion of spinless electron under a driving force due to an applied temperature gradient. This equation is a eapite ad calcem,temperature. Elimination of the rate of change of velocity with respect to time leads to a non-Fourier heat conduction equation with a accumulation of temperature or ballistic term in it. The new constitutive heat conduction equation is combined with the energy balance equation in one dimension. The governing equation for transient temperature a partial differential equation (Eq. (23)) is solved for by the method of Laplace transforms. The problem considered is the semi-infinite medium with constant thermo physical properties with constant wall temperature boundary condition. A closed form analyticalexpression for the transient temperature was obtained (Eq. (36)) after truncation of higher order terms in the infinite binomial series and use of convolution and lag properties. This solution is compared with that obtained using the parabolic Fourier model and the damped wave model as presented in an earlier study. The predictions of Eq. (36) are closer to the Fourier model. The convex nature of the temperature curve is present. 展开更多
关键词 Transport theory non-fourier conduction CWT constant wall temperature binomial infinite series.
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STUDY OF THE EFFECTS OF REDUCING SYSTEMATIC ERRORS ON MONTHLY REGIONAL CLIMATE DYNAMICAL FORECAST
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作者 曾新民 席朝笠 《Journal of Tropical Meteorology》 SCIE 2009年第1期102-105,共4页
A nested-model system is constructed by embedding the regional climate model RegCM3 into a general circulation model for monthly-scale regional climate forecast over East China. The systematic errors are formulated fo... A nested-model system is constructed by embedding the regional climate model RegCM3 into a general circulation model for monthly-scale regional climate forecast over East China. The systematic errors are formulated for the region on the basis of 10-yr (1991-2000) results of the nested-model system, and of the datasets of the Climate Prediction Center (CPC) Merged Analysis of Precipitation (CMAP) and the temperature analysis of the National Meteorological Center (NMC), U.S.A., which are then used for correcting the original forecast by the system for the period 2001-2005. After the assessment of the original and corrected forecasts for monthly precipitation and surface air temperature, it is found that the corrected forecast is apparently better than the original, suggesting that the approach can be applied for improving monthly-scale regional climate dynamical forecast. 展开更多
关键词 climatology monthly regional climate dynamical forecast systematic errors
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Design of a Preview Controller for Articulated Heavy Vehicles
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作者 Mohammad Manjurul Islam Yuping He 《Journal of Mechanics Engineering and Automation》 2013年第11期661-676,共16页
The paper presents a preview controller design for ATS (active trailer steering) systems to improve high-speed stability of AHVs (articulated heavy vehicles). An AHV consists of a towing unit, namely tractor or tr... The paper presents a preview controller design for ATS (active trailer steering) systems to improve high-speed stability of AHVs (articulated heavy vehicles). An AHV consists of a towing unit, namely tractor or truck, and one or more towed units which called trailers. Individual units are connected to one another at articulated joints by mechanical couplings. Due to the multi-unit configurations, AHVs exhibit unique unstable motion modes, including jack-knifing, trailer swing and rollover. These unstable motion modes are the leading cause of highway accidents. To prevent these unstable motion modes, the preview controller, namely the LPDP (lateral position deviation preview) controller, is proposed. For a truck/full-trailer combination, the LPDP controller is designed to control the steering of the front and rear axle wheels of the trailing unit. The calculation of the corrective steering angle of the trailer front axle wheels is based on the preview information of the lateral position deviation of the trajectory of the axle center from that of the truck front axle center. Similarly, the steering angle of the trailer rear axle wheels is calculated by using the lateral position deviation of the trajectory of the axle center from that of the truck front axle. To perform closed-loop dynamic simulations and evaluate the vehicle performance measure, a driver model is introduced and it 'derives' the AHV model based on well-defined testing specifications. The proposed preview control scheme in the continuous time domain is developed by using the LQR (linear quadratic regular) technique. The closed-loop simulation results indicate that the performance of the AHV with the LPDP controller is improved by decreasing rearward amplification ratio from the baseline value of 1.28 to 0.98 and reducing transient off-tracking by 95.03%. The proposed LPDP control algorithm provides an alternative method for the design optimization of AHVs with ATS systems. 展开更多
关键词 Optimal preview control articulated heavy vehicle active trailer steering closed-loop dynamic simulation.
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老龄化压力蒸汽灭菌器BD试验失败原因及对策 被引量:4
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作者 庹琨明 赵卫萍 《中国消毒学杂志》 CAS 北大核心 2014年第8期907-908,共2页
目的分析造成老龄化预真空压力蒸汽灭菌器B-D试验失败因素。方法对2012年3-7月62次B-D试验失败原因进行分析,并采取有效措施。结果 8-10月采取措施后B-D试验成功率提高了16.39%。结论对老龄化压力蒸汽灭菌器采取了一系列有效措施,提高了... 目的分析造成老龄化预真空压力蒸汽灭菌器B-D试验失败因素。方法对2012年3-7月62次B-D试验失败原因进行分析,并采取有效措施。结果 8-10月采取措施后B-D试验成功率提高了16.39%。结论对老龄化压力蒸汽灭菌器采取了一系列有效措施,提高了B-D试验的成功率,延长了灭菌器的使用寿命。 展开更多
关键词 B-D试验 动式真空灭菌器 灭菌质量
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Analysis of promoters of microRNAs from a Glycine max degradome library 被引量:1
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作者 Yi-qiang HAN Zheng HU +1 位作者 Dian-feng ZHENG Ya-mei GAO 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE CAS CSCD 2014年第2期125-132,共8页
Objective: MicroRNAs (miRNAs) are genome-encoded, small non-coding RNAs that play important functions in development, biotic and abiotic stress responses, and other processes. Our aim was to explore the regu- latio... Objective: MicroRNAs (miRNAs) are genome-encoded, small non-coding RNAs that play important functions in development, biotic and abiotic stress responses, and other processes. Our aim was to explore the regu- lation of miRNA expression. Methods: We used bioinformatics methods to predict the core promoters of 440 miRNAs identified from a soybean (Glycine max) degradome library and to analyze c/s-acting elements for 369 miRNAs. Results: The prediction results showed that 83.86% of the 440 miRNAs contained promoters in their upstream se- quences, and 8.64% (38 loci) in their downstream sequences. The distributions of two core promoter elements, TATA-boxes and transcription start sites (TSSs), were similar. The cis-acUng elements were examined to provide clues to the function and regulation of spatiotemporal expression of the miRNAs. Analyses of miRNA cis-elements and targets indicated a potential auxin response factor (ARF)- and gibberellin response factor (GARF)-mediated negative feedback loop for miRNA expression. Conclusions: The features of miRNAs from a Glycine max degradome library obtained here provide insights into the transcription regulation and functions of miRNAs in soybean. 展开更多
关键词 Glycine max MicroRNA (miRNA) PROMOTER Cis-acting element Prediction
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Precision of future experiments measuring primordial tensor fluctuation 被引量:1
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作者 WANG Yi MA YinZhe 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2014年第8期1466-1470,共5页
Recently the second phase of Background Imaging of Cosmic Extragalactic Polarization (BICEP2) claimed a detection of the tensor-to-scalar ratio (r) of primordial fluctuation at 50- confidence level. If it is true,... Recently the second phase of Background Imaging of Cosmic Extragalactic Polarization (BICEP2) claimed a detection of the tensor-to-scalar ratio (r) of primordial fluctuation at 50- confidence level. If it is true, this large and measurable amplitude (r - 0.2) of B-mode polarization indicates that it is possible to measure the shape of CMB B-mode polarization with future experiments. Given the current understanding of the experimental noise and foreground contamination, we forecast the precision of r and the tensor spectral index nt measurements from Planck, Spider and POLARBEAR with nt as a free parameter. We quantitatively determine the signal-to-noise of the measurement in r-nt parameter space for the three experiments. The forecasted signal-to-noise ratio of the B-mode polarization somewhat depends on r/t, but strongly depends on the true value of r. 展开更多
关键词 B-mode polarization BICEP2 tensor spectral index
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Unusual Event Detection and Prediction in Real-life Scenes
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作者 张一 杨杰 《Journal of Shanghai Jiaotong university(Science)》 EI 2010年第1期19-23,共5页
In this paper,we consider unusual event detection problem in a novel viewpoint and provide an algorithm to solve the problem.The actions or events in the scene is usual or not will eventually be reflected on the chang... In this paper,we consider unusual event detection problem in a novel viewpoint and provide an algorithm to solve the problem.The actions or events in the scene is usual or not will eventually be reflected on the changes of some basic features.We summarize these basic event features and propose special representation for each of them.Thus we can model these features in a uniform mode using adaptive Gaussian mixture model.Supervised and unsupervised unusual event detection algorithm can be designed to fit various situations based on this model.The superiority of our model is that it can detect unusual event automatically without to know the determinate model of unusual events.In conclusion,we provide two applications to verify the effectiveness of our model. 展开更多
关键词 unusual event detection adaptive Gaussian mixture model linear discriminant analysis hidden Markov model trajectory distance metric
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