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1.
网络流量具有高度复杂的非线性特征,采用单一预测模型往往难以达到理想的预测效果,为此,提出一种包容性检验和BP神经网络相融合的网络流量预测模型(ET-BPNN)。首先采用多个单一模型对网络流量进行预测,然后通过包容性检验,根据t统计量检验选择最合适的基本模型,最后采用BP神经网络对基本模型预测结果进行组合得到最终预测结果。实验结果表明,相对于单一模型以及传统组合模型,ET-BPNN更加准确刻画了网络流量变化趋势,各项评价指标均达到更优,为实现网络流量准确预测提供了更为科学的方法。  相似文献   

2.
汪洋  田钢  温淑鸿 《电视技术》2014,38(6):94-96
电视节目收视率预测是一种典型非线性预测,收视率在短时间内相对稳定。人工神经网络具有良好的容错性、自适应学习能力以及非线性映射能力,采用人工神经网络做收视率预测精度较高。基于BP神经网络建立了预测模型,并采用软件仿真的方式对预测过程以及预测结果进行分析,实验结果表明采用BP神经网络预测电视节目收视率是可行的。  相似文献   

3.
区域物流需求预测的应用研究   总被引:1,自引:0,他引:1  
为了提高区域物流需求精度,综合考虑区域物流需求线性、周期性和非线性信息,提出了采用组合模型的预测方法.通过将各种单一预测模型看作代表不同信息的片段,通过BP神经网络对不同信息进行集成,充分利用各单项预测方法的有用信息,从而提高区域物流需求预测精度.通过上海市的物流需求数据对组合模型进行测试,实验结果表明,组合模型很好揭示了上海物流需求的变化规律,提高了物流需求的预测精度,为区域物流需求预测提供了一种新的思路和方法.  相似文献   

4.
吕燕红  王芹 《信息技术》2013,(9):128-131
高速公路隧道监控系统存在传感器单一、可靠性低等问题,如果能对失效传感器数据预测,可提高隧道安全性。利用BP和RBF神经网络的非线性逼近能力融合提取隧道CO浓度信息特征,再用最优均方误差加权融合算法对两种网络分别提取的信息再次融合预测隧道CO浓度。提高了模型预测精度,进而给出数据预处理方法和模型评价指标。仿真实验表明:该模型对隧道CO浓度预测的有效性,性能优于单一神经网络融合预测模型。  相似文献   

5.
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   

6.
无线传感器网络的节点运行往往受限于能量供给。对太阳能进行采集并转换成电能存储,可以延长节点的使用寿命。对太阳能进行能量预测,可以更好地规划和使用采集到的能量,这有助于节省能源、避免浪费,提升无线传感器网络的生存周期。针对太阳能预测,提出一种基于自回归积分移动平均-长短期记忆(Autoregressive Integrated Moving Average-Long Short Term Memory, ARIMA-LSTM)组合模型的能量预测方法。首先,采用ARIMA模型来对太阳辐照数据进行预测,提取数据中的线性分量;然后将过滤后的残差代入LSTM神经网络模型,得到非线性分量的预测;最后将二者进行相加,得到最终的预测结果。仿真实验显示,组合模型比起现有的单一模型,能够有效地提高预测的精度。  相似文献   

7.
针对重大事件网络舆情数量的激增,网络舆情安全监管和预警形势严峻的情况,提出一种基于ARIMA和BP神经网络组合模型的网络舆情情感预测模型,进而对新浪微博上采集的"余姚水灾事件"进行文本情感值计算,并对其情感变化趋势进行综合分析和预测。预测结果表明,也组合预测方法相对于单一预测方法具有更高的精度,进而说明该模型在网络舆情情感预测中的应用是可行的。  相似文献   

8.
张斌  廖仁杰 《电子与信息学报》2022,43(10):2944-2951
为提高恶意域名检测准确率,该文提出一种基于卷积神经网络(CNN)与长短期记忆网络(LSTM)相结合的域名检测模型.该模型通过提取域名字符串中不同长度字符组合的序列特征进行恶意域名检测:首先,为避免N-Gram特征稀疏分布的问题,采用CNN提取域名字符串中字符组合特征并转化为维度固定的稠密向量;其次,为充分挖掘域名字符串上下文信息,采用LSTM提取字符组合前后关联的深层次序列特征,同时引入注意力机制为填充字符所处位置的输出特征分配较小权重,降低填充字符对特征提取的干扰,增强对长距离序列特征的提取能力;最后,将CNN提取局部特征与LSTM提取序列特征的优势相结合,获得不同长度字符组合的序列特征进行域名检测.实验表明:该模型较单一采用CNN或LSTM的模型具有更高的召回率和F1分数,尤其对matsnu和suppobox两类恶意域名的检测准确率较单一采用LSTM的模型提高了24.8%和3.77%.  相似文献   

9.
《现代电子技术》2016,(10):30-33
考虑到无线网络流量具有极强的分散性、随机性以及混沌等特性,使用传统的ARIMA预测模型和BP神经网络模型难以对其进行精确的预测等,该文使用粒子群优化算法对BP神经网络预测模型进行优化以解决BP神经网络容易陷入局部最小值以及训练收敛速率低等问题,引入遗传算法中的自适应变异因子来以一定概率初始化部分变量解决粒子群优化算法会出现陷入局部最优解以及早熟收敛等问题。最后使用经典的CRAWDAD数据库中的无线网络流量数据对该文预测方法性能进行测试,使用稳定小波变换方法将无线网络流量数据分解,得到由1个近似分量以及3个细节分量组成的数据流。测试结果表明,该预测算法在预测性能上要优于ARIMA预测模型和BP神经网络模型。  相似文献   

10.
网络流量具有复杂多变特征,为了获得理想的预测效果,提出一种包容性检验和BP神经网络相融合的网络流量预测模型(ET-BPNN)。首先采用多个单一模型对网络流量进行预测,然后通过包容性检验选择最合适的基本模型,最后采用BP神经网络确定基本模型权重,建立网络流量预测模型。结果表明,ET-BPNN更加准确地刻画了网络流量变化趋势,各项评价指标均达到更优,为实现网络流量准确预测提供了更为科学的方法。  相似文献   

11.
This paper presents a brief overview of the Applied Centura(R)DPS(R)system,configured with silicon etch DPS Ⅱ chamber, with emphasis on discussing tuning capability for CD uniformity control. It also presents the studies of etch process chemistry and film integration impact for an overall successful gate patterning development. Discussions will focus on resolutions to key issues, such as CD uniformity, line-edge roughness, and multilayer film etching integration.  相似文献   

12.
We have fabricated the white organic light-emitting devices (WOLEDs) based on 4,4' -bis(2,2 -diphenyl vinyl)-1,1' - biphenyl (DPVBi) and phosphorescence sensitized 5,6,11,12,-tetraphenylnaphthacene (rubrene). The device structure is ITO/2T-NATA (20 nm)/NPBX (20 nm)/CBP: x%Ir(ppy)3:0.5% rubrene (8 nm)/NPBX (5 nm)/DPVBi (30 nm)/Alq(30 nm)/LiF(0.5 nm)/A1. In the devices, DPVBi acts as a blue light-emitting layer, the rubrene is sensitized by a phosphorescent material, fac tris (2-phenylpyridine) iridium [Ir(ppy)3], acts as a yellow light-emitting layer, and N,N' -bis- (1-naphthyl)- N,N' -diphenyl -1, 1' -biphenyl-4,4' -diamine (NPBX) acts as a hole transporting and exciton blocker layer, respectively. When the concentration of Ir (PPY)3 is 6wt%, the maximum luminance is 24960 cd/m^2 at an applied voltage of 15 V, and the maximum luminous efficiency is 5.17 cd/A at an applied voltage of 8 V.  相似文献   

13.
To meet the need of automatic image features extraction with high precision in visual inspection, a complete approach to automatic identification and sub-pixel center location for similar-ellipse feature is proposed. In the method, the feature area is identified automatically based on the edge attribute, and the sub-pixel center location is accomplished with the leastsquare algorithm. It shows that the method is valid, practical, and has high precision by experiment. Meanwhile this method can meet the need of instrumentation of visual inspection because of easy realization and without man-machine interaction.  相似文献   

14.
本论文提出一种在多天线MIMO信道相关性建模中小角度扩展近似理论算法,并应用于分析MIMO系统性能。分析中分别对三种不同角能量分布情况下的空间相关性研发快速近似计算法,并同时提出双模(Bi-Modal)角能量分布情况下的近似运算。通过分析这些新方法的近似效率,可以得到计算简单、复杂度低、而且符合实际的MIMO相关信道矩阵,对系统级的快速高效计算法的研究和系统级的评估以及误差分析具有重要的意义。  相似文献   

15.
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   

16.
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   

17.
Integrated circuits (ICs) intended for increasingly sophisticated automotive applications bring unique test demands. Advanced ICs for applications such as highly integrated automatic braking system (ABS) and airbag controllers combine high voltage digital channels, significant VI demands and precise timing capability. Along with continued missioncritical reliability concerns, the trend toward higher voltage operation and increased device integration requires specialized test capabilities able to extend across the wide operating ranges found in automotive applications. Among these capabilities, automotive test requirements increasingly dictate a need for a cost-effective versatile mixed-signal pin electronics with very high data rates reaching up to 50MHz with a voltage swing of-2 V to +28 V.  相似文献   

18.
This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.  相似文献   

19.
An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.  相似文献   

20.
It is of interest to get appropriate information about the dynamic behaviour of rotating machinery parts in service. This paper presents an approach of optical vibration and deviation measurement of such parts. Essential of this method is an image derotator combined with a high speed camera or a laser doppler vibrometer (LDV).  相似文献   

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