基于图像的火焰稳定性判别方法研究

针对锅炉燃烧监控系统所采集的火焰动态图像,提出了一种基于在线模糊聚类算法的炉内火焰燃烧诊断方法。该方法分析了火焰图像的特点,提取了判别火焰稳定性的特征量,以提取的特征量作为在线模糊聚类算法的输入参数,分析燃烧图像的隶属度,给出判别标准对燃烧稳定性进行综合评估。将在线算法与离线算法进行比较,实验结果表明,在线算法比离线算法的准确率提高了5.3%,验证了算法的有效性。该方法对实现燃烧状态自动监测,保障锅炉安全运行具有重要意义。     

基于Adams的某机枪射击密集度仿真

为研究武器结构对射击密集度的影响,提出一种低伸弹道武器射击密集度的分析方法.采用刚柔耦合分析方法和Adams软件建立某机枪的动力学仿真模型,计算两种枪管设计方案的射击密集度.仿真结果为设计人员进行结构设计及优化提供参考依据.     

基于评分离散度的托攻击检测算法

检测托攻击的本质是对真实用户和虚假用户进行分类,现有的检测算法对于具有选择项的流行攻击、段攻击等攻击方式的检测鲁棒性较差。针对这一问题,通过分析真实用户和虚假用户的评分分布情况,结合ID3决策树提出基于用户评分离散度的托攻击检测Dispersion-C算法。算法通过用户评分极端评分比、去极端评分方差和用户评分标准差3个特征衡量用户评分离散度,并将其作为ID3决策树算法的分类特征,根据不同特征的信息增益选择特征作为分类属性,训练分类器。实验结果表明,Dispersion-C算法对各类托攻击均有良好的检测效果,具有较好的鲁棒性。     

Turbulent flow computations on a hybrid cartesian point distribution using meshless solver LSFD-U

This paper may be considered as a sequel to one of our earlier works pertaining to the development of an upwind algorithm for meshless solvers. While the earlier work dealt with the development of an inviscid solution procedure, the present work focuses on its extension to viscous flows. A robust viscous discretization strategy is chosen based on positivity of a discrete Laplacian. This work projects meshless solver as a viable cartesian grid methodology. The point distribution required for the meshless solver is obtained from a hybrid cartesian gridding strategy. Particularly considering the importance of an hybrid cartesian mesh for RANS computations, the difficulties encountered in a conventional least squares based discretization strategy are highlighted. In this context, importance of discretization strategies which exploit the local structure in the grid is presented, along with a suitable point sorting strategy. Of particular interest is the proposed discretization strategies (both inviscid and viscous) within the structured grid block; a rotated update for the inviscid part and a Green-Gauss procedure based positive update for the viscous part. Both these procedures conveniently avoid the ill-conditioning associated with a conventional least squares procedure in the critical region of structured grid block. The robustness and accuracy of such a strategy is demonstrated on a number of standard test cases including a case of a multi-element airfoil. The computational efficiency of the proposed meshless solver is also demonstrated.     

A novel ordered weighted averaging weight determination based on ordinal dispersion

One of the most common techniques to find the adequate weights in ordered weighted averaging (OWA) operators is based on the orness concept, where the weights are determined by maximizing the entropy (variation) for a fixed orness value. But such an entropy represents a dispersion measure for nominal variables, while weights in an OWA operator are essentially ordinal rather than nominal. Hence, in this paper, we propose a novel way to determine OWA weights based upon ordinal dispersion measures instead of an standard entropy measure. From this approach, we find an explicit formula for the weights, and we illustrate differences by means some multicriteria decision-making examples.     

基于燃烧模型的微弱火焰高度检测

火焰高度是描述火焰特性、确定火焰燃烧状态的重要参数,目前多使用目测方法进行检测.微弱火焰具有亮度低、信噪比低、火焰轮廓模糊的特点,人工目测困难,常规图像分析方法检测对阈值依赖性高.为解决上述问题,在利用常规图像处理方法提取的不完整火焰边缘后,建立火焰轮廓的多参数模型,进而计算火焰高度.实验结果表明:该算法抗干扰能力强,...     

基于案例推理的交通疏导辅助决策方法

为避免实际交通疏导问题中人为主观因素的影响,将案例推理理论应用于交通疏导决策中,提出一种基于案例推理的交通疏导决策方法,建立交通疏导案例库模型。区分属性数据类型,设计基于ID 3信息熵的案例相似度算法,案例匹配时可以兼顾特征属性与案例效果,避免传统算法中属性值缺失的问题。实例验证了该方法能够提高案例推理结果的准确度,对辅助处理交通疏导问题具有一定实际指导意义。     

Spectral analysis of turbulence based on the DNS of a channel flow

The development and assessment of spectral turbulence models requires knowledge of the spectral turbulent kinetic energy distribution as well as an understanding of the terms which determine the energy distribution in physical and wave number space. Direct numerical simulation (DNS) of turbulent channel flow yields numerical “data” that can be, and was, analyzed using a spatial Fast Fourier Transform (FFT) to obtain the various spectral turbulent kinetic energy balance terms, including the production, dissipation, diffusion, and the non-linear convective transfer terms.     

Thermal dispersion effects on non-Darcy convection over a cone

The similarity solution for non-Darcy mixed convection about an isothermal vertical cone with fixed apex half angle, pointing downwards in a fluid saturated porous medium with uniform free stream velocity is obtained. The effect of thermal dispersion is studied in both the aiding and opposing flows. Flow separation is observed when the forced and free convection act in opposite directions. It is interesting to note that when buoyancy effects are neglected, the similarity solution exists for all realistic power law variations of the wall temperature, and for uniform free stream velocity, a closed form solution is possible for the isothermal wall temperature and uniform free stream. The heat transfer is enhanced due to the thermal dispersion effects.     

基于电容传感器的电容近炸引信炸高散布研究

基于电容近炸引信的探测场区为准静电场,根据准静电场的分布特征,类比无线电引信的方向函数,建立电容引信的场强分布函数,得到电容近炸引信的等场强探测方向图近似为一个长短半轴相差20％的椭球,验证了电容近炸引信在不同弹目交会条件下炸高散布小的结论.     

Investigation of pulse dispersion in a carrier‐based UWB system with LO leakage cancellation

Local oscillator (LO) leakage in a carrier‐based ultrawideband (UWB) system is a major design concern. In many cases, mixer LO‐RF isolation is not sufficient and the LO leakage is well above the useful UWB signal. However, this leakage can be substantially reduced by using a notch filter located before the UWB transmitting antenna as long as it will not lead to unacceptable signal distortion. Therefore, various filter parameters, such as the filter order and 3 dB rejection bandwidth, have been studied to see their effects on providing sufficient band rejection level to reduce the unwanted LO leakage while minimizing the transmitted pulse dispersion. Time domain simulations and measurements have been utilized to evaluate the pulse dispersion using both the relative signal's first pulse amplitude and the pulse time delay spread. © 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.     

基于自组织神经网络的炉膛火焰燃烧诊断系统

针对目前大型锅炉火焰检测手段的落后现状,提出了一种基于数字图像处理与自组织竞争神经网络进行燃烧诊断的方法,设计了一套火焰燃烧诊断系统.利用数字图像处理技术提取火焰特征量,应用神经网络的竞争学习对不同负荷下的全炉膛火焰图像进行识别分类,从而实现燃烧诊断和灭火预警的功能.     

基于飞腾处理器的瘦客户机散热结构设计

基于目前国产处理器的瘦客户机整机功耗相对较高,利用常用的无风扇散热的被动散热方式在整机散热性能方面稍显不足,尤其是存在散热死区,从而设计了一种基于飞腾四核处理器的瘦客户机。该瘦客户机采用双散热模组设计,采用4个进风道和2个出风道设计,使得机体内部无散热死区,实现整机超强的散热性能。温度测试数据表明：在25℃环境中,机器满负荷工况运行时,机体内各测试点的温度均在52℃以内,满足所有元器件的工作温度要求;同时,机器箱体外表面温度低于36℃,用户体验感良好。     

双特征模型核相关滤波目标跟踪算法

目的 基于深度学习的目标跟踪算法,利用卷积深层作为特征,虽然精度高但无法做到实时跟踪;基于相关滤波的跟踪算法,利用HOG（histogram of oriented gridients）、CN（color name）和颜色直方图作为特征,速度快但精度较差。为兼顾目标跟踪算法的实时性与准确性,提出了一种基于双模型核相关滤波算法。方法 提出了自适应的双特征模型选择机制,主特征模型采用浅层纹理特征HOG,辅助特征模型采用包含深层语意信息的CNN（convolutional neural networks）特征,二者协同作用,产生更加稳定的相关滤波器。为了提高算法的速度,采用主成分分析（PCA）技术对高维的CNN特征进行降维,并通过尺度优化、最优解求解方式优化等方法提高跟踪算法的准确性。结果 在公开数据集OTB-2013上,本文算法与目前先进且速度能达到实时的SiamFC（fully-convolutional Siamese networks）、MEEM（multiple experts using entropy minimization）、SAMF（scale adaptive multiple features）、DSST（discriminative scale space tracking）等跟踪算法进行比较,一次成功率（OPE）结果显示,本文算法在距离精准度指标中综合排名第一,与KCF（kernel correlation filter）算法相比,本文算法的距离精准度提高了25.2%,重叠成功率提高了25.6%,平均速度达到38帧/s。结论 本文提出的双模型自适应机制,针对主特征模型的置信响应自适应调用最优模型策略,并且实时更新模型,在综合考虑跟踪准确性和跟踪实时性的情况下,本文提出的目标跟踪算法的性能优于目前的跟踪算法。     

基于系统动力学模型的物元相关网研究

在可拓学相关分析理论中,关键在于确定相关基元的函数关系。然而,在具体领域中运用的时候,相关函数的确定往往是比较困难的,也就局限了相关网方法的使用。文章以物元为研究对象,对物元的相关网进行了研究,提出了相关网的动力学模型建模方法以及一种在相关函数未知的情况下,基于系统动力学模型的物元相关函数近似构造方法。该方法的原理是通过基础数据的收集和分析,在依据相关网建立的动力学模型中按照固定的步骤进行模拟分析,得出物元的近似相关函数。在此基础上,相关分析的进行就变得简单、可模拟。案例分析的结果表明,该方法能够有效模拟和近似构造相关物元之间的函数关系,为相关网方法在具体领域中的运用奠定了一定的基础。     

基于ICA方法的朴素贝叶斯分类器

朴素贝叶斯分类器是一种简单而高效的分类器,但需要属性独立性假设,无法表示现实世界中属性之间的依赖关系,影响了其分类性能.利用独立分量分析提升朴素贝叶斯分类性能,把样本投影到由独立分量所确定的特征空间,提高了朴素贝叶斯分类器的分类性能.实验结果表明,这种基于独立分量分析的朴素贝叶斯分类器具有良好的性能.     

基于ICA与Bayes的判别分析模型

简要介绍了Bayes判别分析模型的特点及存在的问题,概括了独立成分分析(ICA)的特点及发展现状,提出了基于ICA与Bayes的判别分析模型--IBD模型.该模型首先利用ICA的方法将相关性数据指标转换为互相独立的数据指标,并通过卡尔曼滤波方式滤去高频数据,有效地去除了噪声,最后利用Bayes方法对转换的数据进行判别分析.实验结果表明,当数据之间存在相关关系时,IBD模型的判别分析效果要优于Bayes与Fisher判别分析模型.     

基于聚类和流量传播图的P2P流量识别方法

为有效监管网络,快速精确识别P2P流量,通过分析P2P网络流量中节点与节点、节点与链路之间的交互和行为特征,将聚类方法与流量传播图方法相结合,提出了一种基于网络行为特征的P2P流量识别方法。该方法首先通过采集网络流的包级和流级统计特征对不同种类的网络应用的流量进行聚类,然后利用流量传播图对P2P流量进行识别。实验结果表明,提出的方法在骨干网络数据上能够有效识别P2P网络应用流量,◢F◣▼1▽-measure达到95%以上。     

Platoon dispersion prediction under the condition of adjacent cycle traffic flow overlapping based on Support Vector Regression

Coordinated signal control can improve the continuity of vehicular traffic flow movement and reduce delay. Cycle Flow Profile is the base for calculating coordinated signal control parameters. Platoon dispersion characteristic determines the Cycle Flow Profile. So, improving platoon dispersion prediction accuracy can obtain significant benefit for signal coordination. When the velocities of the vehicles vary greatly, faster vehicles of next cycle can catch up the slower vehicles of the current cycle. Traffic flow overlapping of adjacent cycle is an important characteristic. Support Vector Regression is adopted to predict platoon dispersion and compares prediction accuracy with Robertson formula. The results are encouraging; Support Vector Regression has higher prediction accuracy.     

基于攻击图与报警相似性的混合报警关联模型

为了揭示入侵检测系统所生成的报警数据之间的关联关系和重构入侵攻击场景,提出了一种基于攻击图与报警数据相似性分析的混合报警关联模型。该模型结合攻击图和报警数据分析的优点,首先根据入侵攻击的先验知识定义初始攻击图,描述报警数据间的因果关联关系,再利用报警数据的相似性分析修正初始攻击图的部分缺陷,进而实现报警关联。实验结果表明,混合关联模型能够较好地恢复攻击场景,并能够完全修复攻击图中单个攻击步骤的缺失。