共查询到20条相似文献，搜索用时 62 毫秒
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迄今的图像质量评价大多从图像本身的参数进行评价,或是从成像系统的调制传递函数来评价。然而从应用的角度来看,对图像质量的一般性评价还不能完全解决图像质量与图像应用效果的关系问题。如何针对有限的应用类型或应用目标来考虑图像质量参数,对于图像质量评价方法的研究是很有意义的。对此进行了论述。 相似文献
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网络视频图像的双距离较远,环境复杂,很难保证压缩还原后的图像质量,使得图像包含大量的随机多维噪声,噪声特征属性呈现多元性,导致传递图像失真。为此,提出了一种基于像素小基团增强的网络课件图像清晰化算法。利用离散小波变换算法对图像进行去噪处理,去除外界因素对图像造成的干扰。利用像素基团能量的观点对图像进行增强处理,保证传递的动态图像的清晰化。实验结果表明,这种算法提高了远程网络视频教育动态图像的清晰度。 相似文献
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传统的自组织神经网络系统进行图像量化处理和编码中,算法对于码书初始值选择具有较强的敏感性,从而导致该量化编码算法对训练序列具有较大的依赖性。为此提出基于自组织神经映射网络系统的低失真敏感测量度图像编码图像量化编码方案,主要是针对初始码书的较强敏感性而改进的,以便改进码书的性能和训练效率。改进的方法中通过设置一个响应的频率计数器。由失真的敏感参数对失真测度进行调整,有效降低失真程度,从而减少了已被用作响应码氏的码氏再度成为响应码氏的概率,实现了对码书性能和数量之间的矛盾进行有效地平衡折中。训练效果和仿真结果表明,方法改进效果明显,其峰值信噪比相比提高了3.75 dB,图像还原效果真实有效,能有效适用于对图像向量量化和编码。 相似文献
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在利用失真测度来描述隐写引起的音频失真时,发现对同一原始音频进行多次直接 序列扩频隐写过程中,第一次隐写引起的失真最为剧烈．从直接扩频隐写的原理出发,提出了 从待检测音频提取相应失真测度作为特征向量,并利用支持向量机进行分类的隐写分析方法． 该方法不需要对原始音频进行估计．实验证明,本方法具有令人满意的性能,对不同嵌入强度 也同样有效,同时对嵌入容量的干扰提出２种改善策略． 相似文献
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企业自主创新过程中知识管理绩效的表现形式、测度及评价研究 总被引：1，自引：0，他引：1
知识管理对自主创新的作用效果是学者和实业家们关注的问题。从知识、行为和技术三个维度深入分析了企业自主创新过程中知识管理绩效的表现形式,构建了定量和定性相结合的知识管理绩效表现形式的测度指标;利用模糊一致偏好关系确定测度指标的权重;提出了自主创新过程中知识管理绩效的云评价模型。以实例说明了知识管理绩效评价流程和评价方法的可行性和科学性:利用模糊一致偏好关系确定权重能在很大程度上减少两两比较的次数并能保证一致性;云评价模型较好地实现了定量指标和定性指标的结合,既能得到综合评价结果,也能分析各指标对整体绩效的作用程度和方向。 相似文献
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<正>太阳短曝光图像对太阳研究具有重要的科研意义。目前太阳望远镜通常采用斑点成像技术达到减轻大气湍流引起的图像变形、扭曲而获得高分辨率太阳图像的目的。斑点成像技术中经常使用帧选择算法遴选出太阳短曝光图像进行重建。为了获得更高质量的重建帧,始终需要找到更好的方法来评价观测太阳短曝光图像的质量,因此质量评价方法是否得当直接影响后续图像重建帧的选择。从多种质量评价方法的仿真实验结果得出,基于梯度相似性的无参考图像质量评价方法能够对太阳短曝光图像质量评价有着较好的结果,从而提高太阳短曝光图像的选帧效率。 相似文献
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[目的/意义]期刊学术影响力是学术界和期刊界关注的热点,已有许多学者对其测度指标结构关系进行了分析,但缺少从整体上对测度指标间相互作用关系的研究。[方法/过程]以632种"综合性人文、社会科学"类期刊为研究样本,构建期刊学术影响力的测度指标体系,运用BP神经网络DEMATEL模型计算各测度指标的中心度与原因度,并结合原因—结果图分析各测度指标的重要性及相互作用关系。[结果/结论]研究结果表明,该模型能较准确地反映出测度指标间的结构关系,他引影响因子和复合总被引为强驱动型指标;平均引文数和影响因子是排名前两位的驱动型指标;5年影响因子为最显著的特征型指标。 相似文献
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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
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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
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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
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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
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《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
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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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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
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Milton Mueller 《The Information Society》2001,17(3):151-163
Long-standing conflict between domain name registrants and trademark holders prompted the Internet Corporation for Assigned Names and Numbers (ICANN) to create a global, mandatory arbitration procedure known as the Uniform Dispute Resolution Policy (UDRP). The UDRP has been used in 2166 cases involving 3938 domain names as of 1 November 2000. The policy gives the initiator of a complaint, generally a trademark holder, the right to choose which ICANN-accredited dispute resolution service provider (RSP) will handle the case. During the preparation of the UDRP,some feared that complainant selection would lead to "forum shopping" that might bias the results. This article performs a statistical assessment of the forum-shopping thesis and finds support for it. There are statistically significant differences in the various RSPs' propensity to take away names from defendants; there are also major differences in the number of cases brought to each RSP. RSPs who take away names have the larger share of cases. The study examines other variables that might explain differences in market share, such as price, the plaintiff's nationality, or the time taken to decide a case. It finds that nationality and time also are correlated with market share. The study concludes that shopping for a favorable outcome is an important factor in the UDRP. 相似文献
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Prof. Raymond C.K. Chen a neuropsychologist with the CAS Institute of Psychology has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology.…… 《中国科学院院刊(英文版)》2008,22(1):15-15
Prof. Raymond C.K. Chen, a neuropsychologist with the CAS Institute of Psychology, has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology. 相似文献
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Leah A. Lievrouw 《The Information Society》1998,14(2):83-96
The main premise of this article is that in information societies generally, and in virtual social contexts particularly, a distinctive style of interaction to facilitate the communication of difference, heterotopic communication , has emerged. It rests on two cultural foundations: an ideological belief in the positive, socially integrating power of communication, and a prevailing ethic of instrumental rationality, subjective individualism, and strategically practiced self-interest. The former is demonstrated by the use of simulation and spectacle as sources of information; exhibitionism/voyeurism as a communicative style; and the awareness of surveillance. The latter is seen in the competitive use of knowledge as a commodity; a surface globalism masking deep parochialism; lateral as well as vertical information inequity; and the use of public versus private as strategies for engagement rather than as spaces. Those who engage in heterotopic communication resort to their 'own devices' both in the sense of personal agendas, strategies, interests, and interpretations, and in the form of the telecommunication tools that help realize them. These personal and technological devices allow individuals with the right educational and technical resources to avoid exposure to disagreement, difference, or other information that does not serve their direct purposes or reflect their particular views of the world; yet they also help convey the appearance of openness, availability, and cooperation. This style of interaction is used strategically in combination with information and communication technologies to gain social or economic advantages, but it may encourage social separatism and parochialism, inhibit the negotiation of disputes, and emphasize competing interests. 相似文献