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1.
目的:建立细菌性痢疾月发病数的预测模型,探讨AR1MA季节乘积模型在时间序列资料分析中的应用。方法:采用非条件最小二乘法估计模型参数,通过季节差分方法使原始序列平稳,按照残差不相关原则、简洁原则确定模型结构,依据AIC和SBC准则确定模型阶数,建立ARIMA预测模型。结果:对所分析的季节性时间序列建立了乘积ARIMA(0,0,1)(0,1,1)12模型。方差估计值为288.106,AIC=619.661,SBC=620.492。对模型进行白噪声残差分析(p=0.632),拟合优度统计量表明ARIMA的估计具体模型为:(1-B12)Zt=(1-0.34B)(1-0.559B12)αt是适合的。结论:通过ARIMA(0,0,1)(0,1,1)12模型与ARIMA(0,1,1)12模型对细菌性痢疾月发病数预测效果的比较,表明ARIMA季节乘积模型是一种短期预测精度较高的预测模型。  相似文献   

2.
分析了除人民币贷款以外的融资方式及其发展情况,通过建立非平稳时间序列(ARIMA)模型,灰色预测GM(1,1)残差模型,自适应过滤法三种,选取残差较小的两种进行组合预测,预计到2018年该比率将会达到77.57%,在此基础上给出相应建议。  相似文献   

3.
针对云服务器系统运行环境具有非线性、随机性和突发性的特点,提出了基于整合移动平均自回归和循环神经网络组合模型(ARIMA-RNN)的软件老化预测方法。首先,采用ARIMA模型对云服务器时间序列数据进行老化预测;然后,利用灰色关联度分析法计算时间序列数据的相关性,确定RNN模型的输入维度;最后,将ARIMA模型预测值和历史数据作为RNN模型的输入进行二次老化预测,从而克服了ARIMA模型对波动较大的时间序列数据预测精度较低的局限性。实验结果表明,ARIMA-RNN组合模型比ARIMA模型及RNN模型的预测精度高,且比RNN模型预测收敛速度快。  相似文献   

4.
黄玲莉  刘小龙 《电视技术》2015,39(9):117-121
针对收视率数据的非线性、突变性等特征,仅采纳单一的预测方法不能全面描述收视率的变化规律,因此提出了一种组合预测模型(ARIMA-BP).首先采用自回归移动平均模型(ARIMA)对收视率进行预测,提取收视率的线性变化规律,再利用BP神经网络对ARIMA模型的预测值进行进一步的组合预测,提取收视率的非线性变化特征.本文以广州电视综合频道及在广州市场上的其余8个电视频道19:00 ~20:00时间段的收视率为例进行实证分析,结果表明组合模型比单一采用ARIMA、BP神经网络进行预测的拟合效果好、精度高.  相似文献   

5.
石庆研  岳聚财  韩萍  王文青 《信号处理》2019,35(12):2000-2009
高效精确的航班飞行轨迹预测是未来空中交通管理系统的关键技术之一,其旨在提高空中交通的运行能力和可预测性。针对现有的航迹预测方法预测精度和稳定性不足的问题,在已有的历史航迹数据的基础上,构建了新的特征维度,分析了经度、纬度和高度三维数据的统计特性,将长短期记忆网络(Long Short-Term Memory,LSTM)对非线性和非平稳时间序列有较强的逼近能力,而差分自回归移动平均模型(Autoregressive Integrated Moving Average,ARIMA)对线性时间序列的处理能力更优的特点相结合,提出了一种以LSTM为主ARIMA为辅的组合短期航迹预测模型,先利用LSTM作为主预测模型对经纬度和高度进行预测,再利用辅模型ARIMA对高度的线性关系进行建模,最后采用CRITIC方法将LSTM和ARIMA预测的高度值融合处理。实验结果表明,这种组合模型利用了两种模型的优势,提高了航迹预测的准确性。   相似文献   

6.
根据已监测到的水质数据进行预测一直是河流水质管理的重要组成部分,其中河流营养盐浓度是影响水质的根本因素。文中研究RBF神经网络在河流营养盐浓度预测中的适用性,并与传统的时间序列预测模型:ARIMA进行比较。以朱衣河为研究对象,对河流营养盐主要成分之一的磷酸盐浓度进行预测。通过采集到的时间序列数据对两种预测模型进行仿真,并通过平均误差和均方误差的比较,证明基于RBF神经网络的时间序列预测模型具有较强的预测精度和良好的推广价值能力,在河流营养盐预测中有较高的实用性。  相似文献   

7.
根据车站的人流密度数据,利用ARIMA模型进行了预测,将非平稳的时间序列进行差分,得到平稳化的时间序列,通过Durbin-Watson检验测试数据的稳定性并观察ARIMA模型的残差平均值和方差以及连续残差的自相关性。通过将数据按照比例分为训练集和数据集来对模型进行评估,得到模型的评估得分。为了进一步提高车站人流密度的预测精度,建立基于k-means聚类的ARIMA组合预测模型,通过k-means聚类算法将问题一中得到的主要影响因素的数据集进行聚类,观察每一类数据的组内特点,对每一类数据重新利用ARIMA模型进行预测,然后计算出组合模型的评估得分。  相似文献   

8.
以1995-2010年十年的海南旅游业总收入时间序列数据作为样本,根据时间序列趋势图模型,建立ARIMA(2,2,1)模型,并结合统计软件Eviews6.0来实现模型试验。选择一个相对最优的模型,从而获得最适合的海南省旅游业总收入预测模型,为海南省的旅游业发展提供建议。  相似文献   

9.
考虑到目前单一路段行程时间预测方法性能不稳定的情况,提出卡尔曼滤波预测(Kalman)和时间序列分析(ARIMA)组合模型进行路段行程时间的预测。利用Kalman模型良好的实时性和ARIMA强大的线性拟合能力,以两种模型分别对同一路段行程时间进行独立的预测,再将这两子模型所得预测结果进行动态加权,以最优模式组合模型以达到最佳预测目的。研究表明,组合模型吸取了两模型的各自优点,其预测准确性高于各独立预测模型,是预测路段行程时间的有效方法。  相似文献   

10.
基于ARIMA模型的网络流量预测   总被引:15,自引:1,他引:14  
:网络流量预测在网络规划、流量管理等方面起着重要的作用,是业务管理的主要研究内容之一。在分析研究网络流量实测数据的基础上,建立了网络流量预测的ARIMA模型,该模型较之传统的Poisson过程、Markov过程等随机模型,能更好地描述Internet多构性、突发连续性和自相似性等特征。在模型定阶之后,运用改进的线性建模方法推导确定了模型参数。给出了不同预测步数条件下的流量预测数据,并和流量实测值进行了对比实验。实验结果表明,该模型在预测步数较小(l<3)的情况下,预测误差在5%左右。  相似文献   

11.
DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.  相似文献   

12.
The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.  相似文献   

13.
Today, micro-system technology and the development of new MEMS (Micro-Electro-Mechanical Systems) are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.  相似文献   

14.
The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.  相似文献   

15.
From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.  相似文献   

16.
This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel's.  相似文献   

17.
Waveguide multilayer optical card (WMOC) is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling & processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic (VB) language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.  相似文献   

18.
In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal (200) (2d = 0.4027 nm) is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line(w), the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line(x), the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines(y), the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line(z) in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line(q) in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution(λ/△ 2) is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.  相似文献   

19.
High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET > PDMAT > TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.  相似文献   

20.
It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output(MIMO) communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.  相似文献   

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