基于文本量化分析的区块链政策比较研究     

王启飞  程梦丽  殷敏越  张毅 《科技管理研究》2022,(13)

摘要：本文基于LDA主题建模和Logistic回归等文本量化分析方法,从政策主题、政策工具及创新价值链等三个维度对我国中央及地方政府的区块链政策进行全面的比较分析。研究发现：中央政府主要运用法规管制和技术基础设施两种政策工具,重点关注基础理论研究和技术研发环节,而地方政府主要运用试点示范与资金投入等政策工具,重点关注区块链产业应用环节。为更好地促进区块链技术协调发展,应当优化政策工具结构配比,强化人才建设和技术支持;完善环境型政策工具内部结构,提高需求型政策工具的应用比重,构建与创新价值链相应环节高度匹配的政策工具组合。  相似文献   

基于垂直协作视角的农户清洁生产关键点研究   总被引：5，自引：0，他引：5  

应瑞瑶  薛荦绮  周力 《资源科学》2014,36(3):612-619

本文以山东、江苏、福建、江西、四川五省的648个养猪户为样本,运用结构方程模型,对不同垂直协作下,农户的清洁生产关键点及其对农户绩效的影响进行比较分析。结果表明：①在不同的垂直协作下,农户的过程控制和末端治理行为之间均交互影响;②在市场交易下,农户清洁生产关键点有3个：疾病防疫、粪便及病死猪处理、饲料及添加剂的购买和使用;在参与生产合同、合作社下,农户清洁生产有2个关键点：疾病防疫、粪便及病死猪处理;③在两种情况下,疾病防疫环节的清洁生产行为均与农户利润呈正相关;粪便及病死猪处理环节的清洁生产行为均与利润呈负相关;饲料及添加剂的购买和使用在市场交易下与农户利润呈负相关,但是在生产合同、合作社下与农户利润呈正相关。这一结论对于厘清农户清洁生产的关键防控点,有针对性的对农户生产环节进行管控和优化,有一定的理论价值和现实指导意义。  相似文献   

Discussion: With Choices Come Consequences     

Henry Braun 《Educational Measurement》2009,28(4):52-55

The Growth Model Pilot Program (GMPP) was introduced as a response to criticism of the reliance of No Child Left Behind on status‐based indicators. Although incorporating a growth component appears to be a step in the right direction, it adds a level of complexity that brings to the fore new concerns. Three of the four papers in this special issue address different manifestations of a common problem: how choices related to implementation of the GMPP, made on technical or practical grounds, can have substantial consequences for schools and teachers. The fourth paper explicates a different approach to growth modeling. Together these papers add considerably to our understanding of the strengths and weaknesses of growth‐based indicators. In this discussion, I attempt to set these papers in a larger context before providing brief reviews. I conclude by arguing that the nation will be better served if policy makers appreciated the consequences of choices before they crafted legislation and the accompanying regulations.  相似文献   

A Comparison of Label Switching Algorithms in the Context of Growth Mixture Models     

Kristina R. Cassiday  Youngmi Cho  Jeffrey R. Harring 《Educational and psychological measurement》2021,81(4):668

Simulation studies involving mixture models inevitably aggregate parameter estimates and other output across numerous replications. A primary issue that arises in these methodological investigations is label switching. The current study compares several label switching corrections that are commonly used when dealing with mixture models. A growth mixture model is used in this simulation study, and the design crosses three manipulated variables—number of latent classes, latent class probabilities, and class separation, yielding a total of 18 conditions. Within each of these conditions, the accuracy of a priori identifiability constraints, a priori training of the algorithm, and four post hoc algorithms developed by Tueller et al.; Cho; Stephens; and Rodriguez and Walker are tested to determine their classification accuracy. Findings reveal that, of all a priori methods, training of the algorithm leads to the most accurate classification under all conditions. In a case where an a priori algorithm is not selected, Rodriguez and Walker’s algorithm is an excellent choice if interested specifically in aggregating class output without consideration as to whether the classes are accurately ordered. Using any of the post hoc algorithms tested yields improvement over baseline accuracy and is most effective under two-class models when class separation is high. This study found that if the class constraint algorithm was used a priori, it should be combined with a post hoc algorithm for accurate classification.  相似文献   

矩阵在数学建模中的应用举例     

刘鹏 《楚雄师范学院学报》2006,21(6):4-9

矩阵作为一种认识复杂事物的简捷工具已经被广泛应用在各个学科领域中,在数学建模中也有许多应用。本文就数学建模中使用矩阵的情况做一些举例、小结,最后给出一个典型的数学模型。  相似文献   

Abilities and skill acquisition: A latent growth curve approach     

Manuel C. Voelkle  Werner W. Wittmann  Phillip L. Ackerman 《Learning and individual differences》2006,16(4):303-319

The relationship between abilities and skill acquisition has been the subject of numerous controversies in psychology. However, while most researchers implicitly or explicitly accept the idea that abilities and skill acquisition should be related, empirical research has failed to provide evidence for a consistently strong correlation between the two constructs. Based on the reanalysis of a study on skill acquisition using the air traffic controller task TRACON [Ackerman, P. L., Kanfer, R., and Goff, M. (1995). Cognitive and Noncognitive Determinants and Consequences of Complex Skill Acquisition. Journal of Experimental Psychology. Applied, 1(4), 270–304], it will be shown how latent growth curve modeling can help to gain a better understanding of the relationship between human abilities and skill acquisition. A brief introduction into the basic concepts of latent growth curve modeling will be given, particularly with regard to the advantages for the analysis of skill acquisition and its determinants. The goal is thereby to provide evidence for a much closer association than commonly assumed and to offer a new, differential, perspective formerly obscured by traditional between-subject analyses.  相似文献   

Models for illuminating things otherwise unseen: Co-editor’s introduction     

Gregory R. Hancock 《Contemporary educational psychology》2007

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玉溪市个私经济发展的思考     

李崇科 《玉溪师范学院学报》2003,19(4):16-18

个私经济要在新的形势下获得快速发展 ,必须结合实际 ,进一步转变思想观念 ,重视制度创新、经营方式创新和技术创新 ,搞好结构调整 ,开发人力资源 ,提高员工素质 ,讲求社会效益 ,依法管理 ,使其发展潜力充分发挥出来。  相似文献   

对我国48～56 kg级高水平男子散打运动员专项运动素质结构的研究   总被引：6，自引：0，他引：6  

于慧 《沈阳体育学院学报》2005,24(5):121-124

采用体育测量和统计分析等方法,选取有代表性的专项运动素质指标进行分析,对我国48～56kg级高水平男子散打运动员专项运动素质结构加以研究.正确分析散打专项运动素质与运动成绩的关系,以期为小级别男子散打运动员的专项运动素质训练提供科学的理论依据,最终为提高我国散打运动水平服务.  相似文献   

世界优秀健美操选手成绩结构特征的技术分析     

钟明宝 《浙江体育科学》2000,22(2):14-17

主要运用等级相关分析的方法,结合国际健美操竞赛规则的要求,以第四届世界健美操锦标赛决赛前八名选手为主要研究对象,分析运动成绩与各项技术指标以及各项技术指标之间的相关性,从技术的角度探讨世界优秀健美操选手成绩结构特征,并针对我国选手的表现提出建议。  相似文献