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1.
提出一种基于高频增强和区域标定的涡轮叶片缺陷定位检测算法,设计涡轮叶片缺陷定位检测工作原理,采用高频滤波的方法来锐化叶片图像,采用预处理的办法来初步控制过度分割现象,由灰度图像生成梯度图像,构建一个噪声抑制算子,解决过度分割问题,进行了涡轮叶片的缺陷特征模型构建和缺陷信息计算,采用高频增强算法和区域标记的方法,减少由于噪声和纹理细节产生的伪边界,提高缺陷定位性能。仿真实验表明,采用该算法能有效提高涡轮叶片的缺陷定位检测性能,突出损伤边界,较好地抑制噪声。具有较高的工程应用价值。 相似文献
2.
《科技通报》2015,(12)
遥感图像中存在大量微小红外目标,对其准确的分类和定位识别是实现远程目标识别和遥感测量的基础。目前对该类红外小目标的识别方法采用单层正方形网格生成方法,对随机标定的红外目标点的识别效果不好。提出一种基于Harris角点检测的遥感图像中微小红外目标的分类定位识别算法。构建遥感图像的红外目标数据采集模型,对图像进行角点特征提取预处理,采用Harris角点检测算法实现对红外目标微小特征点的信息标定,实现对其准确分类定位。仿真实验表明,采用该算法进行微小红外目标的分类定位识别,具有较高的准确性,对红外目标的特征提取和定位识别效果较好,在远程目标探测和遥感监测等领域具有较高的应用价值。 相似文献
3.
在虚拟手术系统模型中,特别是脑外科手术中,由于背景图像色彩的非规则性和非均匀性,导致对脑部损伤区域的手术入刀切割点的定位不准,影响手术精度和效果。传统方法采用损伤区域差异特征信息提取方法实现入刀点定位,对脑部特征二维灰度图片缺陷边界的定位效果不佳。提出一种基于背景差分法的虚拟手术损伤区入刀点定位算法,构建了虚拟手术的总体结构模型,将背景图像和人体软组织目标图像划分为多个子块,基于直方图选择阈值对差分图像序列进行二值化,得到高斯虚拟人体器官解析模型。设计医学图像分割算法,采用背景差分技术确定手术器械与软组织发生碰撞的激励因子,快速获取碰撞点,实现对虚拟手术入刀点的准确定位。实验结果表明,采用该算法实现虚拟手术系统设计和图像重构,对手术过程中器官损伤区域切割入刀点定位准确,性能优越,视景效果较好,计算时间缩短,精度提高。 相似文献
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《科技通报》2015,(12)
CCD固态图像传感器用于遥感图像采集中,遥感对地探测中进行图像采集的轮廓线特征模糊,需要进行自适应轮廓线跟踪标记,提高图像的分析和识别能力。传统方法采用尺寸配准标定技术,对边缘模糊的遥感CCD成像标记效果不好,出现伪轮廓。提出一种基于Harris角点检测的遥感对地CCD成像自适应轮廓线跟踪标记算法。进行遥感对地CCD成像图像数据模型构建,设计Harris角点检测算法进行CCD遥感成像的边缘轮廓像点拟合,进行边缘轮廓线的亮点分析,提高采样精度,通过遥感成像的运动幅度检测实现对轮廓线跟踪标记。仿真结果表明,算法能有效实现CCD成像轮廓线跟踪标记高精度拟合,能有效剔除边缘干扰,提高对地遥感观测图像的探测精度。 相似文献
6.
车道检测系统中的关键问题是图像分割,而图像分割的基础则是自适应阈值的确定。本文针对车道检测系统对比了不同的自适应阈值算法,并采用物理模型仿真的研究方法简要分析了这几种算法的特性,最终确定了一种各项性能指标均较优的自适应阈值算法。 相似文献
7.
车床在对零件进行切削加工时,零件全程都处于高速旋转运动中。由于存在零件塑性变形现象和刀具积屑瘤现象,使得零件在加工过程中容易出现缺陷部位,造成零件质量下降,因此需要及时检出零件缺陷部位并调整机床,避免缺陷部位进一步扩大。传统的检测方法误差大,不能对零件缺陷部位进行准确定位,降低了对零件加工过程检测的准确性。为此,提出一种基于辅助视觉的零件加工过程检测方法。对加工过程中零件缺陷部位的辅助视觉图像出现同现的频率进行统计,计算缺陷部位图像在所有图像中的同现度,通过计算得到对应图像的权重,实现缺陷部位关键帧图像定位,利用缺陷图像中心点的位置建立数学模型,实现对零件缺陷部位的检测。实验结果表明,利用辅助视觉算法在零件加工过程中能够快速准确的对零件的缺陷部位进行检测。 相似文献
8.
随着大数据信息技术的发展,数据在线监测和数据挖掘成为计算机信息领域研究的热点。通过对Web热点数据分割挖掘,提高信息热点追踪和Web数据分类能力。传统算法采用非结构化数据挖掘算法,无法有效对Web热点数据进行准确定位和分层挖掘。提出一种基于半结构化分割的Web热点数据挖掘算法。采用半结构化数据进行特征分割,基于优秀基因位进行差分进化,使寻优曲线不断趋于平缓,在多个节点上并行的运行比较脚本,采用半结构化分割,使得Web热点特征挖掘实现自适应寻优,得到Web热点数据的分配因子,提高了挖掘性能。仿真结果表明,该算法获得了良好的效率和精度,提高了Web热点数据挖掘的自适应寻优能力。 相似文献
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当前对Wi-Fi网络节点故障定位方法使用正交频分复用技术,采用直调直检的方法将Wi-Fi节点网络之间高速数据信号转换为分布式载波信号,实现节点故障节点检测,该方法很容易导致相邻节点信道间频谱主瓣重叠,在非常态干扰下定位不准。提出一种基于OFDM技术的Wi-Fi故障节点定位方法,采用同步算法来减小子载波间的正交性抑制,采用信息素更新策略实现在非常态干扰下对故障节点的定位检测。仿真实验表明,该方法能有效定位Wi-Fi故障节点,网络传输误码率降低明显,大幅提高网络传输效率,有效提高了Wi-Fi网络可靠性和应用性。 相似文献
11.
A research group led by Prof. ZHAI Qiwei from the Institute for Nutritional Sciences under the CAS Shanghai Institutes for Biological Sciences has discovered that even relatively low doses of resveratrol-a chemical found in the skins of red grapes in red wine-can improve the sensitivity of mice to the hormone insulin according to a report in the October issue of Cell Metabolism.…… 《中国科学院院刊(英文版)》2008,22(1):14-15
Aresearch group led by Prof. ZHAI Qiwei from the Institute for Nutritional Sciences under the CAS Shanghai Institutes for Biological Sciences has discovered that even relatively low doses of resveratrol--a chemical found in the skins of red grapes and in red wine--can improve the sensitivity of mice to the hormone insulin, according to a report in the October,2007 issue of Cell Metabolism. As insulin resistance is often characterized as the most critical factor contributing to the development of Type 2 diabetes, the findings“provide a potential new therapeutic approach for preventing or treating” both conditions, the researchers said. 相似文献
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《中国科学院院刊(英文版)》2008,22(1):2-3
CAS should stick to the principle of rendering service to, and giving impetus for, the development of China＇s science enterprise by making S＆T innovations, said CAS President LU Yongxiang. The CAS president made the remarks in a recent talk to communicate the gist of the winter session of the Party＇s Leading-member Group at CAS, which was held from 7 to 11 January in Beijing. 相似文献
13.
Marjorie Armstrong-Stassen Margaret Landstrom Ramona Lumpkin 《The Information Society》1998,14(2):153-164
This study examined how students who had no prior experience with videoconferencing would react to the use of videoconferencing as an instructional medium. Students enrolled in seven different courses completed a questionnaire at the beginning of the semester and again at the end of the semester. Students at the origination and remote sites did not differ in their reactions toward videoconferencing but there was a significant difference for gender. Women reacted less favorably to videoconferencing. Compared to the beginning of the semester, students reported significantly less positive attitudes toward taking a course through videoconferencing at the end of the semester. There were no significant differences in students' attitudes toward videoconferencing across courses at the beginning of the semester but there were significant differences across the courses at the end of the semester. The results suggest the need for better preparation for both students and instructors. 相似文献
14.
《中国科学院院刊(英文版)》2008,22(1)
With great care, Dr. ZHOU Zhonghe takes out a package wrapped by cotton tissue from a drawer and says: "This is the gem of our collections: the fossil of a bird that lived 125 million years ago!" Then, pointing at a tiny mound, he explains: "Look, this is the claw and that is the head. It was in the egg shell and ready to hatch ... The species fell into a family of waterside inhabitants." 相似文献
15.
A joint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology his co-workers from Norway US Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells suggesting that China's projected climate warming could decrease the pest's numbers. The study was published in Proceedings of the National Academy of Sciences on September .…… 《中国科学院院刊(英文版)》2008,22(1):6-7
Ajoint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology and his co-workers from Norway, US and Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells, suggesting that China＇s projected climate warming could decrease the pest＇s numbers. The study was published in Proceedings of theNational Academy of Sciences on 17 September, 2007. 相似文献
16.
Active biological molecules functional structures can be fabricated into a bio-mimetic system by using molecular assembly method. Such materials can be used for the drug delivery disease diagnosis therapy new nanodevice construction.…… 《中国科学院院刊(英文版)》2008,22(1):22-22
Active biological molecules and functional structures can be fabricated into a bio-mimetic system by using molecular assembly method. Such materials can be used for the drug delivery, disease diagnosis and therapy, and new nanodevice construction. 相似文献
17.
Caroline Haythornthwaite 《The Information Society》2001,17(3):211-226
A computer-mediated group is a complex entity whose members exchange many types of information via multiple means of communication in pursuit of goals specific to their environment. Over time, they coordinate technical features of media with locally enacted use to achieve a viable working arrangement. To explore this complex interaction, a case study is presented of the social networks of interactions and media use among members of a class of computer-supported distance learners. Results show how group structures associated with project teams dominated who communicated with whom, about what, and via which media over the term, and how media came to occupy their own communication niches: Webboard for diffuse class-wide communication; Internet Relay Chat more to named others but still for general communication across the class; and e-mail primarily for intrateam communication. Face-to-face interaction, occurring only during a short on-campus session, appears to have had a catalytic effect on social and emotional exchanges. Results suggest the need to structure exchanges to balance class-wide sharing of ideas with subgroup interactions that facilitate project completion, and to provide media that support these two modes of interaction. 相似文献
18.
Electronic data interchange (EDI) provides means for interorganizational communication, creates network externalities, requires an advanced information technology (IT) infrastructure, and relies on standards. In the diffusion of such innovations, institutional involvement is imperative. Such institutions contain governmental agencies, national and global standardization organizations, local government, and nonprofit private organizations like industry associations. The last type of organizations we call intermediating institutions. They intermediate or coordinate ("inscribe") the activities of a group of would-be adopters. Unfortunately, little is known of how these organizations shape the EDI diffusion trajectory. In this article we examine one specific type of intermediating organizations?industry associations?and how they advanced the EDI diffusion process in the grocery sectors of Hong Kong, Denmark and Finland. We identify six institutional measures, placed into a matrix formed by the mode of involvement (influence vs. regulation) and the type of diffusion force (supply push vs. demand pull), that can be mobilized to further the EDI diffusion. Industry associations were found to be active users of all these measures to varying degrees. Their role was critical especially in knowledge building, knowledge deployment, and standard setting. Furthermore, institutional involvement varied due to policy and cultural contingencies and power dependencies. 相似文献
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Leah A. Lievrouw 《The Information Society》2000,16(2):155-159
This essay focuses on universal service and the Internet as means to support social and political participation. The emphasis on access to telecommunications systems in conventional approaches to universal service is contrasted with access to content. A model of the information environment is described that accounts for the roles of content and conduit, both of which are necessary conditions to achieve true access. A method is outlined for employing information indicators to observe or measure the information environment. 相似文献
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Puay Tang 《The Information Society》1998,14(1):19-31
The increasing prospects of digital piracy has prompted the perceived need by electronic publishers to adopt technical systems of protection, and governments to reform their copyright laws. This article is a preliminary study of the management of intellectual property by electronic publishers, defined as those involved in the production of online databases, and CD-ROMs. It focuses on three main issues: (1) how electronic publishers view the increasing threat of piracy; (2) the methods of protection employed to protect intellectual property in digital format; and (3) the importance of technological protection of intellectual property in electronic publications. The analysis is based on a sample of 23 UK electronic publishers. The interviews revealed an interesting assortment of protection methods and did not show that technological protection was a preferred way. Instead, the means of protection, in addition to copyright law, comprised niche markets, pricing, trust, bad publicity, and nontechnical and technical means. 相似文献