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Beck M 《Newsweek》1982,99(14):33
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The forensic science community raised the need for improved evidence recognition, collection, and visualization analytical instrumentation for field and laboratory use. While the 3D optical techniques for imaging static objects have been extensively studied, there is still a major gap between current knowledge and collecting high‐quality footwear and tire impression evidence. Among optical means for 3D imaging, digital fringe projection (DFP) techniques reconstruct 3D shape from phase information, achieving camera‐pixel spatial resolution. This paper presents a high‐resolution 3D imaging technology using DFP techniques dedicated to footwear and tire impression capture. We developed fully automated software algorithms and a graphical user interface (GUI) that allow anyone without training to operate for high‐quality 3D data capture. We performed accuracy evaluations and comparisons comparing with the commercial high‐end 3D scanner and carried out qualitative tests for various impressions comparing with the current practices. Overall, our technology achieves similar levels of accuracy and resolution with a high‐end commercially available 3D scanner, while having the merits of being (1) more affordable; (2) much easier to operate; and (3) more robust. Compared with the current practice of casting, our technology demonstrates its superiority because it (1) is non‐destructive; (2) collects more evidence detail than casts, especially when an impression is fragile; (3) requires less time and money to collect each piece of evidence; and (4) results in a digital file that can easily be shared with other examiners.  相似文献   
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This article examines the structure of the Malian fertiliser value chain and its performance in the context of the national subsidy programme, drawing on a review of the literature, farm household survey, and interviews with fertiliser suppliers. It finds that participants in the subsidy programme use more fertiliser and have significantly higher yields. The number of wholesalers and retailers has risen, but procurement remains concentrated. Poor fertiliser quality is a recurrent problem. The high cost of the programme raises questions regarding its sustainability. Mixed performance reflects the need for better monitoring and evaluation, and transparency in the programme.  相似文献   
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In this study we examine responses to the recent expansion of information technology in two rural Minnesota towns. One of these towns took a cooperative approach to technology access, developing a community electronic network, while the other town relied on a more individualistic, entrepreneurial model. The present study examines citizens' attitudes concerning social, political, and technological issues in these two communities, with the goal of uncovering what kinds of attitudes and resources citizens need to have in order to help support and sustain a community electronic network. Structural equation modeling is used to specify the relationships among individuals' economic, political, and social resources, technology ownership and use, and awareness of and support for the community network. Drawing on a theory of social capital, we consider the relative importance of privately- oriented social engagement versus publicly- oriented political engagement in relation to collective outcomes. Our analysis shows that in the town with the broadly- based community electronic network, individuals' political as well as economic resources are linked to knowledge and use of computer resources, whereas in the comparison community, economic stratification alone drives computer access. The implications of these findings for issues of equity, access to technology, and the development of strong community ties are discussed.  相似文献   
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