差分法

Following is the main contribution of the dissertation. 1 Based on quartile and first order differential, a new outlier detection algorithm is presented, Experiments show that the method combining with low pass filter can remove gross error and unwanted frequency components.

本文的主要工作与创新点在于： 1）将分位数方法与一阶差分法相结合，提出了一种基于一阶差分的粗差剔除方法，该方法与低通滤波器的结合可以有效去除两相流压力波动信号中的粗大误差以及信号频带以外的频率成分。

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前者主要采用帧间差分法和背景差分法。

Finite difference method is adopted in this model to analyze the temperature distribution and fulgurite resistance of a fuse.

针对所提出的简化模型，用直接差分法进行数值模拟，设计出用直接差分法进行数值计算的通用程序，实现了温度分布和弧后残躯电阻的数值分析。

Temperature field is obtained by Direct Finite Difference Method with parallelepiped mesh elements and the latent heat release is handled with a combination of equivalent specific heat method and temperature recovery method.

计算方法采用直交剖分的直接差分法；潜热处理采用等价比热法与温度修正法相结合的方法；在节约内存量和提高计算速度的基础上尽可能提高计算精度，并在三者之间取得合理平衡；对直交剖分带来的误差采用了热容量修正技术；针对不同铸造合金的凝固特点，对收缩缺陷判据进行了研究和扩展。

But it suffers from the following two shortcomings:(1) the object detected by instantaneous difference is inherently interfered by "virtual shadow" noise;(2) the interior detection of an object might be partly lost whenever the grey scale is quite uniform.

文章提出基于两次差分之间相关性的"复合差分法"，实现了对"虚影"的消除，并提出一种判定最优差分间隔的策略，减少了目标漏检，使目标检测的完整性得到了显著提高。

An algorithm for moving objects detection based on Gaussian Mixture Model and Three-Frame Differencing is proposed to detect the moving objects.

为了有效检测出运动目标，提出一种将基于混合高斯模型的背景差分法和三帧差分法相结合的算法。

The finite difference time-domain method is stable and easy to be used, but due to the fact that it approximates the space derivatives in Maxwells curlequations by central difference, FDTD usually requires more than 20 grids perwavelength to achieve acceptable accuracy. As a contrast, pseudospectraltime-domain method approximates the space derivatives by pseudospectralmethod, which guarantees the accuracy, theoretically requiting only 2 grids perwavelength.

传统的电磁场数值算法——时域有限差分法稳定而易于实现，但由于FDTD采用中心差分近似Maxwell旋度方程的微分，每个波长上需要取的网格数通常较多，而时域伪谱法采用伪谱法求微分，理论上每个波长只需要取两个网格便可以达到较高的精度。

First, we introduce the linearly distributed stress tensors as the source and by means of two-dimensional finite-difference scheme to obtain the response of this source, then the point source response is generated by correcting both the wave forms and geometrical spreadings for the linear respons.

但在理论地震学，工程地震学和勘探地震学中横向不均匀介质中的波传播问题非常重要，此时使用有限差分法和有限元法等离散数值方法比较有效。鉴于目前计算工具的限制，三维模型的有限差分计算虽然在理论上是可行的，但很少能用于实际。

The first step is to eliminate all kinds of noises generated in the process of collecting traffic video by means of median filter; Then we finish image sharpening with Laplace operator to clarify edges of the video images; finally, image contrast is enhanced with the help of the second-developing packet SDK-2000, which is provided by our video-collecting card. This way, much more satisfactory images are obtained, and preparation is already made for the following work, thats image analyse.Thirdly, according to the characteristics of our system, mobile objects are distinguished by means of image difference. Then some features such as regional area, length and width of traffic objects are selected and extracted. After processing of scale filter, we successfully recognize those moving vehicles appearing in the monitoring regions.Fourthly, some corresponding algorithms are brought forward to automatically identify those familiar traffic peccancies of many sorts, such as red light violation, yellow-line covering, parking in prohibited spots, over-speed running and converse running. Then we find means to snap pictures and to intercept videos of the spot, and collect a lot of relevant information such as the time, the block, the running direction and the weather conditions and so on. According to this information, our traffic management departments could make correct decisions on punishing those drivers who have broken the traffic rules.Considering the complexity of traffic environments on particular blocks, in order to monitor other traffic peccancies effectively, we also have designed the scheme to carry out traffic monitoring by manual.

首先运用中值滤波法对视频图像进行去噪处理，然后采用二阶差分法进行图像锐化，再通过视频捕获卡携带的二次软件开发包SDK-2000进行对比度增强，从而得到比较理想的图像，为后续的图像分析工作做准备；第三，根据系统特点，通过背景图像差分法，分割出监测区中的运动目标，然后对交通目标的区域面积、长度和宽度等进行特征提取，再经过尺度滤波处理，从而自动识别出机动车辆目标：第四，分别设计相应的算法，实现对闯红灯、压黄线、违章停车、违章超速及违章逆行等常见的交通车辆违章行为的自动识别，并自动抓拍违章现场，截取违章视频，采集其它相关违章信息，为交通执法部门进行交通违章处罚提供有力依据：考虑到特殊路段特殊环境下的交通复杂性，为了有效监控其它类型的交通违章行为，本文还设计并实现了对交通违章的手动监控模式。

The numerical solution of carbon diffusion was solved and the finite difference method was used, the inner boundary conditions of the meshes were treated using diffusional flux and carbon's activity, and adaptive software was assembled. The system of identification indicated that the numerical results were accordant to the expermental results.

用有限差分法寻求异种接头碳扩散的数值解，利用扩散通量和扩散驱动力活度的知识处理了网格的内边界，编制了相应的软件，辨识结果表明用有限差分法进行异种接头界面碳扩散迁移的定量计算和状态辨识与试验结果的分布趋势是一致的。

Cynanchum Lingtai apricot production in the average weight 65 grams, the brightly-colored fruit, juicy rich, sweet-sour taste, sweet from the nucleolus, when the late Qing Dynasty famous Shaanxi, Gansu provinces, the Qing imperial court Tongzhi tribute for years.

灵台生产的牛心杏平均单果重65克，果实色泽鲜艳，汁多味浓，甜酸适口，离核仁甜，清末时就驰名陕、甘两省，清同治年间曾为朝廷贡品。

Chenopodium album,Solanum nigrum, and Amaranthus retroflexus were very susceptible to the herbicides. Polygonum persicaria and Abutilon theophrasti were relatively less susceptible to the herbicides, and Lycopersicon esculentum was not susceptible to it. The relationship between reduction rates of weed biomass and PPM values of weed leaves 2,4, and 6 days after treatment was established.

供试的6种杂草对该混剂的敏感性存在显著差异：红心藜Chenopodium album、龙葵Solanum nigrum和反枝苋Amaranthus retroflexus对该混剂最敏感，ED90值分别为47.65、71.67和29.17g/hm2；春蓼Polygonum persicaria和苘麻Abutilon theophrasti敏感，ED90值分别为96.91、114.20g/hm2；而番茄不敏感。