基于P（x）-Laplace流的向量值图像恢复模型     

董刚 《人天科学研究》2010,(2):168-170

提出一种基于变指数型扩散方程的向量值图像（例如RGB图像或多谱图像）恢复模型。在新的模型中,我们利用光滑后向量值图像的几何流形特征来判断图像的真假边缘,利用P（x）-Laplace型扩散系数来控制扩散量和扩散方向。由于扩散系数具有良好的自适应判断边缘能力,新的模型在图像恢复的同时良好地保持了图像边缘。通过数值实验,对比以往的全变差模型,所提模型具有更好的图像恢复效果,明显减少了＂块状＂效应。  相似文献   

Digital speckle pattern interferometric measurement of diffusioncoefficients in hydrogels     

周金芳  韩雁  章献民  徐坚 《Journal of Zhejiang University. Science. B》2003,(2)

ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｒａｔｅｏｆｄｉｆｆｕｓｉｏｎｏｆｓｕｒｆａｃｔａｎｔｓｉｎｇｅｌｓｉｓａｎｉｍｐｏｒｔａｎｔｐｒｏｐｅｒｔｙｂｏｔｈｆｏｒｔｈｅｃｈａｒａｃｔｅｒｉｚａ ｔｉｏｎｏｆｓｏｌｕｔｅ ｇｅｌｉｎｔｅｒａｃｔｉｏｎｓａｎｄｆｏｒｔｈｅｄｅｓｉｇｎｏｆｎｏｖｅｌａｐｐｌｉｃａｔｉｏｎｓｏｆｓｕｃｈｍａｔｅｒｉａｌｓ (Ｋｏｎｇｅｔａｌ.,1 997) .Ｃｏｎｖｅｎｔｉｏｎａｌｌｙ ,ｄｉｆｆｕｓｉｏｎｃｏｅｆｆｉ ｃｉｅｎｔｓｉｎｇｅｌｓａｒｅｍｅａｓｕｒｅｄｂｙｍｏｎｉｔｏｒｉｎｇｔ…  相似文献   

Inter-Parietal White Matter Development Predicts Numerical Performance in Young Children     

Cantlon JF  Davis SW  Libertus ME  Kahane J  Brannon EM  Pelphrey KA 《Learning and individual differences》2011,21(6):672-680

In an effort to understand the role of interhemispheric transfer in numerical development, we investigated the relationship between children's developing knowledge of numbers and the integrity of their white matter connections between the cerebral hemispheres (the corpus callosum). We used diffusion tensor imaging (DTI) tractography analyses to test the link between the development of the corpus callosum and performance on symbolic and non-symbolic numerical judgment tasks. We were especially interested in the interhemispheric connections of parietal cortex in 6-year-old children, because regions of parietal cortex have been implicated in the development of numerical skills by several prior studies. Our results revealed significant structural differences between children and adults in the fibers of the corpus callosum connecting the left and right parietal lobes. Importantly, these structural differences were predictive of individual differences among children in performance on numerical judgment tasks: children with poor numerical performance relative to their peers exhibited reduced white matter coherence in the fibers passing through the isthmus of the corpus callosum, which connects the parietal hemispheres.  相似文献   

团队知识扩散的行为难题与组织学习的内在逻辑   总被引：1，自引：1，他引：1  

施杨  成晓芳  李南 《科学学与科学技术管理》2007,28(5):88-91

通过对团队知识扩散相关表征的界定,确定了复杂环境下团队知识共享与整合的基本认知。与此同时,对知识扩散行为难题的剖析,引出组织学习是影响其有效配置的内在动力。在此基础上,从学习能力、学习平台、学习效用以及学习氛围等方面充实了团队知识扩散的相关思路。  相似文献   

A framework for analysing blockchain technology adoption: Integrating institutional,market and technical factors     

《International Journal of Information Management》2020

The adoption of blockchain technologies require the consideration of a broad range of factors, over and above the predominantly technology focus of most current work. Whilst scholarly literature on blockchain technology is only beginning to emerge, majority are focused on the technicalities of the technology and tend to ignore the organizational complexities of adopting the technology. Drawing from a focused review of literature, this paper proposed a conceptual framework for adoption of blockchain technology capturing the complex relationships between institutional, market and technical factors. The framework highlights that varying outcomes are possible, and the change process is focal as this shapes the form blockchain applications take. Factors presented in the framework (institutional, market and technical) interact and mutually influence each other. The proposed framework can be used by organisations as a reference point for adopting blockchain applications and by scholars to expand, refine and evaluate research into blockchain technology.  相似文献   

The “sailing ship effect”: Reassessing history as a source of insight on technical change     

《Research Policy》2013,42(10):1724-1738

The so-called “sailing ship effect” has often been stated as though there is no doubt that it really took place in the end of the 19th century. The notion has, moreover, been used as a stylised fact that is in charge of conveying the idea that the substitution threat of new radical technologies may lead to a renewed spurt of innovation in an old and established technology. On the basis of quantitative evidence and a systematic review of the field of maritime history this paper shows that the effect is nowhere to be found in the very case it derives its name from. The modernisation of the sailing trader occurs before, not after, the steamship had become an effective competitor. It is argued that if history is to be used to give credence to explanations of empirical regularities in a variety of settings the original source of the relevant concepts must be carefully revisited and deeply researched.  相似文献   

No inventor is an island: Social connectedness and the geography of knowledge flows in the US     

《Research Policy》2022,51(2):104416

Do informal social ties connecting inventors across distant places promote knowledge flows between them? To measure informal ties, we use a new and direct index of social connectedness of regions based on aggregate Facebook friendships. We use a well-established identification strategy that relies on matching inventor citations with citations from examiners. Moreover, we isolate the specific effect of informal connections, above and beyond formal professional ties (co-inventor networks) and geographic proximity. We identify a significant and robust effect of informal ties on patent citations. Further, we find that the effect of geographic proximity on knowledge flows is entirely explained by informal social ties and professional networks. We also show that the effect of informal social ties on knowledge flows is greater for new entrepreneurs or ‘garage inventors’, for older or ‘forgotten’ patents, and for flows across distant technology fields. It has also become increasingly important over the last two decades.  相似文献   

Environment and Policy Factors Shaping Global E-Commerce Diffusion: A Cross-Country Comparison   总被引：1，自引：0，他引：1  

Jennifer Gibbs  Kenneth L. Kraemer  Jason Dedrick 《The Information Society》2003,19(1):5-18

This article examines the key global, environmental and policy factors that act as determinants of e-commerce diffusion. It is based on systematic comparison of case studies from 10 countries--Brazil, China, Denmark, France, Germany, Mexico, Japan, Singapore, Taiwan, and the United States. It finds that B2B e-commerce seems to be driven by global forces, whereas B2C seems to be more of a local phenomenon. A preliminary explanation for this difference is that B2B is driven by global competition and MNCs that "push" e-commerce to their global suppliers, customers, and subsidiaries. This in turn creates pressures on local companies to adopt e-commerce to stay competitive. In contrast, B2C is "pulled" by consumer markets, which are mainly local and therefore divergent. While all consumers desire convenience and low prices, consumer preferences and values, national culture, and distribution systems differ markedly across countries and define differences in local consumer markets. These findings support the transformation perspective about globalization and its impacts. In terms of policy, the case studies suggest that enabling policies such as trade and telecommunications liberalization are likely to have the biggest impact on e-commerce, by making ICT and Internet access more affordable to firms and consumers, and increasing pressure on firms to adopt e-commerce to compete. Specific e-commerce legislation appears not to have as big an impact, although inadequate protection for both buyers and sellers in some countries suggests that mechanisms need to be developed to ensure greater confidence in doing business online.  相似文献   

Brazil in the Age of Electronic Commerce     

Paulo Bastos Tigre 《The Information Society》2003,19(1):33-43

E-commerce is growing rapidly in Brazil, led by information-intensive and transaction-intensive sectors such as finance, manufacturing, and retail/wholesale. However, Brazil's highly uneven income distribution is a major barrier for B2C diffusion. Government policies have emphasized promotional or enabling initiatives such as e-procurement, tax filings, and providing Internet access to social institutions. E-commerce legislation is just now being developed, and decisions on taxation are being negotiated in the context of international agreements. E-commerce raises issues for Brazil in terms of its relationship to the global economy. Although most online purchases involve imported goods, e-commerce also offers opportunities to participate in international value chains.  相似文献   

不同形貌的MOF-5纳米颗粒的制备及其氮气吸附性能研究     

汪强  辛志峰  张千峰 《黄山高等专科学校学报》2014,(3):54-58

在室温下,用六水合硝酸锌和对苯二甲酸为原料,通过扩散三乙胺制备了金属有机框架结构（MOF-5）的纳/微米颗粒.通过控制反应体系中水的含量,得到了不同形貌的纳/微米颗粒.通过扫描电子显微镜观察样品MNMOF-6的形貌为纳米颗粒的聚集体,每个纳米颗粒的直径为50-100纳米,样品MNMOF-7,MNMOF-8和MNMOF-9的形貌分别为棒状、针状和带状,我们对不同形貌的MOF-5纳微米颗粒的氮气吸附性能进行了表征.  相似文献