共查询到20条相似文献，搜索用时 187 毫秒
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本文针对结构相似度模型在图像质量评价方面存在的缺陷,提出一种基于视觉感知梯度的结构相似度图像质量评价模型。该模型从误差可视性和内容可视性两方面描述感知函数,并结合图像的梯度地图得到基于视觉梯度的对比度函数和结构函数,以代替结构相似度模型中的对比度分量和结构分量。实验结果表明,GM_SSIM模型较SSIM模型更符合人眼视觉特性,与图像的主观评价结果相一致,尤其适合对失真较严重的模糊图像进行质量评价。 相似文献
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依据空间相似分解模型,将误差图像进行分解,考察无关分量和相关分量对图像质量的影响.本文将相关分量加入标准图像中,结合HVS模型中的掩盖效应,提出了一种新的图像质量评价方法.结果表明,该方法较之传统客观方法更加符合人眼的主观感受.相关分量与标准图像结构一致,不会对人眼产生新的变化. 相似文献
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图像边界是图像质量评价的主要因素。提出了一种结合图像边界的各向异性和奇异性等因素定义边界强度,利用边界的正规性定义边界保持度,然后结合人眼视觉的掩蔽效应和凸效应来建立数学模型,以此度量图像质量。实验结果表明,该方法在对模糊图像和对图像边缘、纹理要求高的领域,其质量评价优于现有的评价方法。 相似文献
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袁玲 《喀什师范学院学报》2011,32(3):50-53
提出一种基于曲波的彩色图像盲水印算法.该算法使用Arnold映射作为混沌系统,对水印图像做预处理,根据人眼的视觉特性,抽取人眼最不敏感的Q分量做曲波变换,并且对曲波的低频系数分块进行SVD分解,将水印以一定的深度嵌入到每个分块的最大奇异值上.实验证明,该算法透明性好,抗攻击能力强,是一种有效的图像鉴定算法. 相似文献
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虹膜识别中,图像质量除受到采集设备、环境光照、目标位置、目标状态等因素影响外,错误的图像分割也会导致图像质量下降,因此单一量度或较少量度都不能准确评价用于匹配计算的虹膜图像质量.基于此设计了可用虹膜区、虹膜大小、清晰度、扩张度等八个评价因子;研究了各评价因子所表征的图像质量特性;提出了利用图像分割参数计算各评价因子的方法;根据实验得到的各评价因子阈值以及图像分割可能的错误,对质量评价因子进行校准;最后融合校准后的因子形成虹膜图像质量评价值.实验结果显示所提出的方法可有效评价虹膜图像质量. 相似文献
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随着智能交通的不断发展、监控设备的更新换代,交通监控系统获取到的图像信息每年都在成倍增长,其直接影响就是摄像设备采集到的无用信息太多,如何对其中的图像信息进行质量评价以及筛选是一个重要问题。为了改善这一现象,提出一种基于视觉显著性的交通图像质量评价方法。该方法将图像抽样成一些随机的感兴趣区域,然后对这些区域进行计算,最后得到显著性图像。实验结果表明,基于视觉显著性的交通质量评价方法效率高、实用性强。该方法得到的显著性图像明显符合人眼的视觉特性以及感兴趣区域,达到了预期效果。 相似文献
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基于教育评估的顶层设计影响力构成因素主要有主体、内容、时机、责任。它们共同决定影响力强度,其中,主体恰当是影响力强的基础,内容科学是影响力强的关键,时机适宜是影响力强的条件,责任严明是影响力强的保证。 相似文献
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Structural bionic design lacks mature and scientific theories, and the excellent structural characteristics of natural organisms sometimes cannot be transferred into engineering structures effectively. Aiming at overcoming the existing problems, this paper summarizes three related theories: similarity theory, fuzzy evaluation theory and optimization theory. Based on the related theories, a method of structural bionic design is introduced, which includes four steps: selecting the most useful structural characteristic of natural organism; analyzing the structural characteristic finally chosen for engineering problem; completing the structural bionic design for engineering structure; and verifying the structural bionic design. Similarity theory and fuzzy evaluation theory are employed to achieve Step 1. In Step 2 and Step 3, optimization theory is employed to analyze the parameters of structures. Together with the thoughts of simplification and grouping, optimization theory can reveal the relationship between organism structure and engineering structure, providing a way to structural bionic design. A general evaluation criterion is proposed in Step 4, which is feasible to evaluate the performance of different structures. Finally, based on the method, a structural bionic design of thin-walled cylindrical shell is introduced. 相似文献
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新建本科院校毕业生就业质量评价指标体系及其权重测算 总被引：2，自引：0，他引：2
新建本科院校毕业生就业质量评价,从影响因素看,包括个人因素、高校因素、用人单位因素、社会因素;从评价指标看,包括工作环境、专业对口、薪酬收入、社会保障、稳定性、职业发展、心理满意度等七大指标体系;从指标权重看,可运用层次分析法对其权重进行测算,研究表明,“职业发展”对毕业生就业质量影响度最高。 相似文献
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This study evaluates the validity of a similarity judgments test (SJT) for assessing conceptual knowledge. 89 high school seniors judged the semantic similarity of a set of concepts. The resulting scores are calculated using a correlational approach as well as the MDS and Pathfinder approaches, respectively. The validity of the SJT is estimated by comparing (a) the scores with the test scores resulting from a multiple-choice test, (b) the scores resulting from pre- and post-instruction, and (c) the scores of students with high vs. low expertise. Our results support the validity of the SJT and show that both the correlational and the Pathfinder approach outclass the MDS approach. Recommendations to evaluate the SJT are provided. 相似文献
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AbstractThis paper presents a study which aims to validate a scale for assessing the impact of Web 2.0 in education. From a structural perspective, we evaluate the influence of various factors (Training, Attitude and Use of Web 2.0) on the Impact of Web 2.0 in education with a sample of 403 students from different degrees of the University of Huelva, applying a Likert scale constructed for this purpose. To analyse the psychometric properties of the scale, we conducted a Chronbach’s Alpha reliability test and factor analysis. To validate the theoretical construct, we conducted an analysis according to structural equation modelling, which enabled us to confirm the influence of training, attitude and use on the Impact of Web 2.0, and to observe how the factors interrelate and influence each other. We conclude that the existence of a training plan is not enough in itself and that, rather, it is the approach taken to Web 2.0 and the use made of it that has more influence on its educational impact. 相似文献
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工程量清单计价模式下的模糊相似优先比快速估价 总被引：1，自引：0，他引：1
杨明辉 《福建工程学院学报》2008,6(2):160-163
随着建筑市场的逐步规范,实行工程量清单计价已成为必然.从工程量清单计价的基本原理出发,分析影响各个工程量清单专业工程及措施项目的造价因素,建立模糊相似优先比模型,选取与工程量清单专业工程及措施项目最相似的项目,最后组合最相似项目得到建筑工程造价,其特点快速、准确,减少了人的主观性,具有一定的科学性和可靠性. 相似文献
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David R. Linden 《Learning & behavior》1976,4(4):451-456
Rats trained to make an approach response with either nonreward or 150- or 175-V shock occurring on 2, 3, or 4 of 6 daily trials showed greater resistance to extinction than continuously reinforced-unpunished controls. Persistence during extinction was a function of both the type and the frequency of response-contingent event in acquisition. The significant interaction of these two factors was best interpreted as a result of the counterconditioning of the approach response (Amsel, 1972) to anticipatory conditions which varied in similarity to the frustrative nonreward of extinction. 相似文献
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运用问卷调查法,对影响新建本科院校学生网上评教活动的评教态度、评教心理等因素进行了调查。结果表明:学生评教态度对网上评教活动的影响各年级之间差异较大,而学生评教心理对网上评教活动的影响各年级之间没有明显差异。 相似文献
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Leah Sikoyo 《Cambridge Journal of Education》2010,40(3):247-263
This article explores teachers’ experiences of implementing the problem‐solving approach; a learner centred pedagogic innovation prescribed by a centrally mandated curriculum in Uganda. It presents teachers’ interpretations of the pedagogic principles suggested by the innovation as well as their accounts of challenges of implementing the pedagogic approach. The findings suggest that the teachers’ implementation of the problem‐solving approach was far more regulated by contextual affordances and constraints within schools and the broader education system and society than by their interpretations of the official curriculum. These findings highlight the influence of structural contextual factors in regulating pedagogic practice and teachers’ take‐up of learner‐centred pedagogies in Africa. The evidence from this paper suggests the need for education researchers in developing countries such as Uganda to focus on helping teachers develop strategies for teaching large classes as learner‐centred pedagogies have a bleak future in the region. 相似文献
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Pei-Ying Chen 《Asia Pacific Journal of Education》2019,39(1):79-95
The main objective of this study was to examine the factors of individual characteristics (e.g., self-regulation in terms of metacognition and motivation) and learning environmental expectancy (e.g., performance expectancy, effort expectancy, and social influence) that influence students’ behavioural intention to continue online courses. The questionnaire data collected from 312 college students were analyzed using the structural equation modelling approach to examine the relationship between self-regulation and the Unified Theory of Acceptance and Use of Technology model. The experimental results revealed that self-regulation in terms of metacognition and motivation directly related to performance expectancy, effort expectancy and social influence. In addition, performance expectancy, effort expectancy and motivation significantly and directly influenced students’ intention to use online courses. However, this study found that metacognition and social influence did not positively directly relate to behavioural intention. The discussion of the present findings and practical implications for possible future research have also been analyzed and concluded. 相似文献