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排序方式: 共有910条查询结果,搜索用时 15 毫秒
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S. Mancuso F. Ferrini F. P. Nicese 《The Journal of Horticultural Science and Biotechnology》2013,88(6):777-784
SummaryThe potential use of the artificial neural networks (ANNs) for characterization and identification of seventeen chestnut (Castanea sativa Mill.) accessions, belonging to the ``marrone''-type and ``chestnut''-type, was investigated in genotypes originating from regions of Italy. Different back-propagation neural networks (BPNN) were built on the basis of image analysis parameters of the leaves, for two tasks of chestnut classification. In the first case a BPNN was built and trained to differentiate the 17 accessions of chestnut. In the second case a BPNN was conceived to distinguish between the ``marrone'' and ``chestnut'' types. BPNN produced a clear identification of all the accessions except in the case of `Garrone nero', `Garrone rosso' and `Tempuriva', which showed almost the same output diagram. Cluster analysis separated the 17 chestnut genotypes into four main groups whose differences were related to the original sources of the genotypes and to the type of affiliation (``marrone''-type or ``chestnut''-type). Artificial neural network technique was also able to discriminate between ``marrone''-type and ``chestnut''-type accessions. Qualitative and quantitative rules for the image analysis parameters, useful for classifying chestnut accessions into these two types, were obtained. On the whole the relative importance of the leaf parameters reveals that ``typical'' leaves for ``marrone''-type are more elongated, of a darker colour and with a higher perimeter/area ratio than the leaves of the ``chestnut''-type. 相似文献
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Scientific studies using direct agricultural air quality (AAQ) measurement have experienced revolutionary changes since such a study was first reported in the early 1950s. Comprehensive AAQ research with multi-institutional or international collaboration, long-term monitoring, and multi-pollutant measurement has been conducted with greater frequency. On-site computer system (OSCS), consisting of data acquisition hardware, a personal computer, and custom-developed AAQ research software has become an important tool in these studies. The role of the OSCS has been expanded from exclusively data acquisition to a combination of data acquisition, control, regular and advanced data processing, and communication. This paper studied the general and specific requirements of OSCS in AAQ research and introduced a system with new methodology and technology for high level quality assurance and quality control (QAQC).Data acquisition in AAQ studies is needed for five main categories of instruments and sensors: pollutant concentrations, air exchange, weather conditions, building status, and measurement system status. Regular data processing consists of converting electrical signals to engineering units, averaging data over a given period of time, and performing data correction. Advanced data processing includes calculating location-shared analyzers and sensors (LSAS) data and instrument calibration data and generating daily reports in real-time or upon user requests. The primary control needs in AAQ research centers around the LSAS using multi-point air sampling system. Controls for sampling tubing heating and equipment cooling are often required. Computer communications to monitor system status, deliver alarms and data, and provide remote diagnosis and controls help to reduce operation costs and increase research quality and data completeness.An OSCS that offered flexibility, high capacity, user-friendliness, and high level QAQC was developed for field and laboratory AAQ research. A total of 29 OSCSs have been built and used in various AAQ studies in 13 states in USA for handling a total of more than 3.0 billion data points. The system adapted a set of data processing algorithms as well as some novel features, including All-data Display and Dynamic Run-time Configuration (DDRC), Digital Output DDRC, real-time sampling system monitoring and protection, Global Channel, traceable configuration, and post-measurement data processing. The system also integrated two stand-alone instruments, an Innova multi-gas analyzer and a 7-port Environics gas diluter, which are popular in AAQ research. The strengths, weaknesses, and future development of the system are also discussed. 相似文献
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唐艳 《农业装备与车辆工程》2007,(7):27-29
随着轨道检测手段的不断提高,如何把轨道检测数据高效、快捷地下发到基层施工部门,尽可能快地消除事故隐患、更好地指导线路维修、保障行车安全,以满足日益发展的快速、准高速、高速铁路的要求变得日益重要。论文重点介绍了基于PIC单片机的轨检车数据采集系统的设计,该设计方案提高了轨检车的测量技术,保证了测量的准确性,对快速检查轨道病害,保证铁路运输安全和提高旅客列车的平稳舒适性均能发挥重要作用。 相似文献
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张继敏 《农业图书情报学刊》2006,18(2):98-100
对数字图书馆建设中资源采访所涉压的著作权问题,如组建各类数据库、网络链接、网络导航、数字资源采访等涉厦的著作权问题作了初步的探讨。 相似文献
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运用双阶差分模型探究了并购与新建投资模式下公司避税效应的非对称性,并进一步从事后的视角探究该非对称性是否是影响企业投资模式选择的显著影响因素。研究发现:相比于新建投资,并购增加了收购方会计利润应税所得差异,且实质性地降低了其所得税实际有效税率,这表明不同投资模式下公司避税效应存在理论预期的非对称性。进一步研究发现,改变企业会计利润应税所得差异以及会计利润应税所得操纵程度是影响企业投资模式选择的重要因素。从事后的视角来看,企业很可能为了获取更大程度的公司避税效应而选择并购行为。 相似文献
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陈倩 《辽宁农业职业技术学院学报》2020,22(1):42-45
大学生思想政治教育获得感是衡量实效的“标尺器”、提升质量的“助推剂”和话语转换的“凭证书”,其归根到底是思想政治教育供求平衡的产物。现阶段思想政治教育供给不平衡不充分同大学生需求之间矛盾减削获得感,思想政治教育供给要在把握以情动人、以理服人、以行化人的维度基础上,力求内容既高大上又接地气、形式既含温度又设尺度、氛围既横向搭又纵向建,实现优质供给与需求恰好适配,直接精准提升获得感。 相似文献