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1.
从铜丸丸粒的种类、铜丸粒径的最佳值、铜丸粒径的最佳比例等多角度阐述了卡车横梁抛丸线磨料由钢丝切丸替代铸钢丸方案试验及实施后的效果。  相似文献   
2.
薄壁注塑成型技术   总被引:3,自引:0,他引:3  
由于3C产品向“轻、薄、短、小”方向发展得越来越快,所以薄壁注塑成型技术也受到人们高度重视。介绍了薄壁注塑成型技术产生的背景及其优点,分析了薄壁注塑成型的定义,综述了薄壁注塑成型中的注塑机、模具设计、制品设计和材料选用,探讨了薄壁注塑成型中所面临的主要问题。  相似文献   
3.
针对基于内容的视频检索中的镜头聚类问题,采用了一种基于模拟退火思想改进的K均值聚类算法.该方法提取视频帧的时间信息、均值、方差、偏度和信息熵等颜色直方信息作为特征,利用模拟退火算法全局寻优的能力来改善K均值聚类易陷入局部极值的缺点,从而提高视频镜头聚类的准确性.理论分析和实验结果表明该方法是一种有效的视频镜头聚类算法.  相似文献   
4.
Eyewitnesses to a simulated crime attempted to identify the perpetrator from a computerized mug book. The 208 mug book pictures were presented either 1 mug shot per page or in groups of 12 mug shots per page. Half of the mug books were arranged by similarity to the perpetrator as determined by a facial recognition algorithm, and half were randomly arranged. In contrast to past findings with photospreads, false-positive identifications were significantly higher using the one-at-a-time procedure than the grouped procedure. Results suggest that the best practice for mug books may be the use of groups of pictures per page rather than the one-at-a-time procedure long advocated by experts for use in lineups and photospreads. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
5.
Based on the powerful function of the hidden conditional random fields (HCRF) model in the expression and identification of semantic events and combining the webcast text information, a new framework for wonderful events automatic detection is put forward. Firstly, by analyzing and processing the webcast text, keyword combinations corresponding to each exciting event are obtained. Secondly, by classifying the webcast text to be detected, the happening time labels of each wonderful event are obtained. Thirdly, an HCRF model for semantic shot annotation is built to realize the semantic annotation of multiple types of semantic shots simultaneously, and the semantic shot sequence of the video clip is obtained. Finally, combining the multi-modal semantic clues, an HCRF model for the wonderful events detection and localization is effectively built in the case of small-scale training samples. Based on the mapping relationship among video low-level features, the multi-modal semantic clues and the wonderful semantic events, the inherent patterns of the wonderful events are excavated deeply in the multiple dimensions of the semantic structure, and then the wonderful events automatic detection, localization and segmentation are precisely achieved. Experiments show the effectiveness of this model.  相似文献   
6.
基于内容的体育视频分类是高效管理大量体育视频数据的关键步骤之一,为提高体育视频分类方法的正确率及泛化能力,提出一种基于类型标志镜头与视觉词袋模型相结合的体育视频分类方法.首先给出类型标志镜头的定义,并通过类型标志镜头构建该镜头视频帧训练库;然后构建基于视频帧训练库的金字塔视觉词袋模型,将视频帧标志为归一化的词频向量,使用SVM对视频帧进行分类;再通过分析视频帧分类错误的原因及表现形式提出基于时序连续性孤立帧去除算法,以消除视频帧的错误归类.由于体育视频按组合类型可分为单一体育视频与混合体育视频,因此分别提出了单一体育视频及混合体育视频2种分类算法.实验结果表明,文中算法具有实现简单、处理速度快和准确度高的优点.  相似文献   
7.
该文介绍了软键盘密码输入技术的工作原理,分析了"屏幕快照"黑客窃密技术的攻击原理和流程,针对当前软键盘技术存在的问题提出了相应的改进方案,并用VB编程实现了改进后的软键盘程序。  相似文献   
8.
AlON nanolayers are synthesized on Al substrate by the irradiation of energetic nitrogen ions using plasma focusing. Samples are exposed to multiple (5, 10, 15, 20 and 25) focus shots. Ion energy and ion number density range from 80 keV to 1.4 MeV and 5.6×10^19 m^- 3 to 1.3×10^19 m ^-3, respectively. Moreover, the effect of continuous annealing (473 K and 523 K) on an AlN surface layer synthesized with 25 focus shots is also examined. The main features of the X-ray diffraction (XRD) patterns with increasing focus shots are: (i) variation in the crystallinity of AlN along (111), (200) and (311) planes, (ii) increasing average crystallite size of AlN (111) plane, and (iii) stress relaxation observed in AlN (111) and (200) planes. The crystallinity of AlN surface layer is comparatively better at 473 K annealing temperature. A broadened diffraction peak related to an aluminium oxide phase showing weak crystallinity is observed for 15 focus shots while non-bounded oxides are present in all other deposited layers. Raman and Fourier transform infrared spectroscopy (FTIR) analysis confirm the presence of AlN and Al203 for the surface layer annealed at 473 K temperature. Raman analysis shows that the overlapping of AlN and Al2Oa results in the development of residual stresses. Scanning electron microscope (SEM) results demonstrate that the formation of rounded grains (range from 20 nm to 200 nm) and variations in their microstructures features depend on the increasing number of focus shots. Decomposition of larger clusters into smaller ones is observed.  相似文献   
9.
随着宽方位、高密度三维地震采集技术的发展,需要海量地震采集设备;在地震采集设备资源有限的条件下,或者地震接收成本较高而激发成本相对较低情况下,适于采用“以炮代道”地震采集方式对原设计地震采集排列片做观测系统变换。观测系统变换的前提条件是两种观测系统构建的十字子集相同,以保证面元属性一致,从而达到预期的勘探目标。实际应用结果表明,推拉式观测系统和大十字观测系统均可方便地完成等效子集的构建,实现以炮代道的精确变换,研究这两种观测系统是分析和设计复杂的以炮代道观测系统变换的基础。  相似文献   
10.
沙特沙漠工区地形比较复杂,时间紧,任务量大,如何保证在有限时间内优质、高效完成生产任务本身就是一大难题,而在风季如何保证资料质量及提高生产效率显得更加困难,这就迫切要求施工队伍尽快找到风季施工难点的解决办法。本文对沙特沙漠地区风季施工中各类繁多的施工设备管理、排列布线,收线等问题,特别是噪音源监控和空炮问题,提出了管理方法和方式方面的解决办法,通过生产实践,取得了较好的应用效果。  相似文献   
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