共查询到18条相似文献，搜索用时 187 毫秒
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为了模拟方志类文献老化过程,本文对几种常见文献老化模型进行了比较,并结合志鉴类文献实际情况,最终在莫地列夫公式和丁学东公式的基础上,提出新的老化模型——"丁—莫"修正式,并给出其回归分析的具体解法。 相似文献
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文献老化对数正态分布模型 总被引：1，自引：0，他引：1
为了反映文献老化曲线的形态,减少拟合误差,通过与概率分布函数曲线的对比分析,提出文献老化对数正态分布模型,并给出了此模型引文半衰期的计算方法.通过示例建模验证了模型的有效性,为文献老化研究提供了一种有效的方法. 相似文献
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用能量观点诠释科学文献的老化现象是一种新的理念。从科学文献老化描述出发，运用系统科学和热力学与统计物理学能量理论导出科学文献系统的能量公式，用能量观点和导出的能量公式诠释科学文献老化机理，并对文献老化的本质进行了探讨。 相似文献
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文章探讨了用引用文献分析法研究学科文献老化规律时引文出版年龄的计算处理方法,分析了“表观引文出版年龄”对老化研究结果的影响,并提出了修正公式。 相似文献
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自1960年伯顿和凯布勒给出了“老化解析式”的引文分布函数以来,该公式已被情报学界认为是经典。十多年来,该公式已引起了我国情报学界的关注,并已有多人发表文章阐述各自对该公式的理解。笔者认为,多数人对该公式的理解是符合原文的意思,但也有少数的解释是与原意不符的。或几乎是“颠倒”的。我们认为,出现这些混乱的解释,是因为对统计学上常用的根据统计数据进行函数拟合,并得出分布函数或密度函数这一过程不太了解。因此有必要从概率统计的角度对该公式进行讨论,并根据我们的引文时间分布统计和曲线拟合的实践,对该公式略作评价。 相似文献
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基于化学与经济学期刊引文数据,利用非线性回归分析对Barnett模型在文献老化研究领域应用的合理性进行了验证,结果表明该模型对学科引文数据具有很好的解释度,但同时也存在残差分析结果不理想的缺陷。在此基础上,将互联网作为参数引入老化模型研究中对Barnett原始模型进行了修正,其回归分析结果表明修正模型较原始模型具有更为理想的引文数据解释度与残差分析结果,从而印证了网络环境下文献介质类型与利用方式的变革对老化状况的现实影响。与此同时,还通过网络环境前后Barnett模型回归效果的比较分析进一步揭示了文献老化随互联网普及而趋于延缓的整体态势。通过Barnett文献老化模型的构建、修正与回归分析,以期更为准确地把握网络环境对文献老化的客观影响。 相似文献
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科学文献的增长规律和老化规律及其新的一般模型 总被引：2，自引：1，他引：1
研究了科学文献增长规律和老化规律,利用微分方程法,分别提出了它们新的一般模型,还讨论了零增长问题.用一些包含著名模型的例子来说明新的模型具有良好的综合性. 相似文献
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为了寻找描述科学文献的布拉德福分散定律的综合模型,文中提出了一种微分方程,它的解就是综合模型的公式.然后,举例说明它涵盖了现有的一些著名的模型,从而说明这个新模型具有良好的综合性. 相似文献
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科技领域内期刊出版延时对文献老化的影响 总被引：2，自引：0，他引：2
本文分析了科学领域内的文献老化问题和期刊文献出版延时现状,介绍了常用的老化测度,分析了文献发表延时转移到引文年龄分布上的过程,并定义这一转移过程为文献引用延时效应,建立了实际老化过程的传递函数模型,利用引文分析法和数学模拟方法对出版延时对文献老化的影响进行科学计量研究,得出科技文献出版延时延缓科技成果和信息老化和延缓科学发展的结论。 相似文献
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基于文献老化负指数模型与生命周期曲线并借助函数推导与曲线分析方法,揭示出文献老化率在负指数模型中为常量,而在生命周期曲线下则为时间函数且具有复杂的数学特征。在此基础上,深入探讨了文献生命周期数学模型的理论特征、模型构建与数学验证问题。结果表明对数正态模型能够较好地拟舍学科引文历时分布数据且符合文献生命周期理论曲线与老化率函数的典型数学特征。 相似文献
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现有产品创新研究文献远远多于工艺创新文献,而对于工艺创新机制的研究更为少见。本文结合文献调研、专家访谈和汽车企业工艺实践,构建了汽车企业工艺创新机制理论模型和研究假设,利用结构方程模型对假设进行了检验。研究发现,决策机制对动力机制、组织机制和激励机制有正向作用,但决策机制对企业工艺创新能力没有直接影响;动力机制、组织机制直接影响工艺创新能力,动力机制的作用相对较弱;组织机制对激励机制的正向作用和激励机制对工艺创新能力的正向作用都没有通过检验。本文对丰富工艺创新研究具有重要的学术价值,研究成果有利于促进企业和政府加强对工艺创新重视。 相似文献
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《Information processing & management》2022,59(4):102994
This study investigates the positive and behavioral topic of screen golf, which is often regarded as the most commercially successful virtual reality sports game. Our team analyzed the decision-making process related to screen golf through the widely used the technology readiness and acceptance model to explain the relationships among technology readiness, belief in technology acceptance, and use intentions. The proposed model fit the data satisfactorily, and several of our hypotheses were supported. Structural equation modeling tested the nine hypotheses established based on a literature review, analyzing 350 valid responses obtained through online surveys. Perceived utility (ß = .519**) was the most influential factor in individuals’ plans to participate in the virtual sport. This means that practical considerations such as correcting individuals’ posture and improving their abilities should be prioritized when creating screen golf programs. 相似文献
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Using technology to facilitate learning in universities and other higher education institutions (HEIs) has become common practice due to its ability to reduce barriers related to time and space in traditional learning environments. However, current literature mostly focuses on the use of the technology and not on the use of the information it conveys. Also, very few studies focus on technology adoption in universities and HEIs in developing countries, especially those in Africa. Thus, we propose a model that explains the changing information behaviors of students in this digital age and the effect this has on their learning outcomes. We collected questionnaire data from 303 students and analyzed the data using structural equation modelling partial least squares (SEM-PLS). We found that our proposed model explains 60.2 % of student satisfaction, 24.2 % of academic performance, 24.1 % of information sharing, and 19.8 % of their information exchange behavior. This study confirms that the use of digital information and its antecedent factors have significant effects on the college experience of students. This has several implications for information systems research and practice, especially in the design and assessment of technology use in learning environments. 相似文献
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在耕地不断减少和农业劳动力老龄化程度日益加深的双重背景下,提高土地利用效率对保障农业产出以及国家粮食安全具有重要意义,但农业劳动力老龄化对土地利用效率的影响学界尚未形成一致的定论。本文通过阐述农业劳动力老龄化、农业资本投入与土地利用效率三者之间的理论机制,运用中介效应模型、面板阈值模型,基于粮食主产区鲁豫皖三省621个固定农户5年跟踪调查数据进行实证分析。结果表明：①农业劳动力老龄化不仅直接促进土地利用效率的提高,还通过农业资本投入间接影响土地利用效率,即农业资本投入在农业劳动力老龄化与土地利用效率之间具有中介效应,该中介效应约占总效应的70.286%;②农业资本投入对提高土地利用效率的促进作用受到农业劳动力年龄双重阈值效应的影响,阈值分别为47岁和70岁,农业资本投入的边际报酬呈现出“U”型变化规律。因此短期内对于农业劳动力老龄化不应该持悲观态度,应提高农资利用率,完善农业社会化服务体系;长期来看应完善农村养老保障体系,培育农业新型经营主体。 相似文献
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《Research Policy》2023,52(10):104873
This paper contributes to the literature around the Kaldor–Verdoorn law and analyses the impact of robotisation on the channels through which the law shapes labour-productivity growth. We start with a simple evolutionary reinterpretation of the law that combines Kaldorian and neo-Schumpeterian arguments. We then apply a GMM estimator to a panel of 17 industries in 25 OECD capitalist economies for the period 1990–2018. After elaborating on the general evidence of the evolutionary interpretation of the law, the estimates suggest a positive influence from robotisation: a higher robot density strengthens both the channel that ties labour productivity dynamics with mechanisation, and the one connected with the general advancement of science and technology which joins productivity to aggregate demand. This overall result is robust to several specifications of the underlying econometric model. Moreover, we find some evidence of technological unemployment out of the macroeconomic factor. Results agree with the empirical literature that suggests different impacts from robotisation on the basis of the level of economic activity considered. 相似文献
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The digitalization phenomenon is leveraging new relationship models through the entire supply chain network. In this outlook, blockchain is a cutting-edge technology that is already transforming and remodeling the relationships between all members of logistics and supply chain systems. Yet, while studies on blockchain have gained a relative pace over the recent years, the literature on this topic does not report sufficient research cases on blockchain adoption behavior at the individual level. The present study, therefore, aims to bridge this gap, notably by helping understand the individual blockchain adoption behavior in the logistics and supply chain field in India and the USA. Drawing on the emerging literature on blockchain, supply chain and network theory, as well as on technology acceptance models (TAMs), we have developed a model based on a slightly-altered version of the classical unified theory of acceptance and use of technology (UTAUT). The model being developed was then estimated using the Partial least squares structural equation modeling (PLS-SEM). As the model was eventually supported, the results obtained revealed the existence of distinct adoption behaviors between India-based and USA-based professionals. In parallel, the findings appear as a useful contribution to and a sign of progress for the literature on IT adoption, SCM, and blockchain. 相似文献