Today's Edisons or weekend hobbyists: technical merit and success of inventions by independent inventors   总被引：1，自引：0，他引：1  

Kristina Dahlin  Margaret Taylor 《Research Policy》2004,33(8):1167-1183

We set out to determine if independent inventors can be considered “heroes” or “hobbyists”, that is, if they produce the most or the least influential inventions in a product category. We study patented inventions by independent and firm-based inventors by comparing patents along four dimensions: Patent citation impact, detail, scope, and maintenance. Examining 225 tennis racket patents granted in the US between 1981 and 1991, we find that independent inventors are a heterogeneous group who generate inventions that are overrepresented both among the most impactful and the least impactful patents. The metrics we develop provide insight into ex ante identification of the importance of inventions.  相似文献   

欧盟学校教育质量指标及对我国的启示   总被引：1，自引：1，他引：1  

张培  刘兰玲 《外国教育研究》2004,31(6):40-44

欧盟是一个区域性的国际组织，十分重视地区间的教育交流与合作，欧盟学校质量指标计划就是当下为世界所关注的合作项目之一。文章以《欧盟学校教育质量报告——16项质量指标》为蓝本，阐述了欧盟学校教育质量指标的提出背景、制定目的、指标结构与标准、指标特点及对我国开发教育指标的启示。  相似文献   

Longitudinal Measurement Non-Invariance with Ordered-Categorical Indicators: How are the Parameters in Second-Order Latent Linear Growth Models Affected?     

Yu Liu  Stephen G. West 《Structural equation modeling》2018,25(5):762-777

Models of change typically assume longitudinal measurement invariance. Key constructs are often measured by ordered-categorical indicators (e.g., Likert scale items). If tests based on such indicators do not support longitudinal measurement invariance, it would be useful to gauge the practical significance of the detected non-invariance. The authors focus on the commonly used second-order latent growth curve model, proposing a sensitivity analysis that compares the growth parameter estimates from a model assuming the highest achieved level of measurement invariance to those from a model assuming a higher, incorrect level of measurement invariance as a measure of practical significance. A simulation study investigated the practical significance of non-invariance in different locations (loadings, thresholds, uniquenesses) in second-order latent linear growth models. The mean linear slope was affected by non-invariance in the loadings and thresholds, the intercept variance was affected by non-invariance in the uniquenesses, and the linear slope variance and intercept–slope covariance were affected by non-invariance in all three locations.  相似文献   

农村教育发展指标研究中的若干基本理论问题     

袁桂林  秦玉友 《教育发展研究》2007,(9):60-64

农村教育发展指标可以描述、解释、评价、监测和预测农村教育发展情况,对农村教育发展具有重要价值.而农村教育发展指标建构的基本理论问题研究是农村教育发展指标建构的基础性工作,也是农村教育研究的重要课题.  相似文献   

2012赛季中国足球超级联赛球队成绩与技术统计的多元分析     

问绍飞 《湖北体育科技》2014,(3):231-234

针对足球运动项目的特点,通过运用因子分析法提取原参数指标的共性因子,建立影响球队成绩的共性因子得分标准化变量线性组合式。根据因子得分排名,对其差异性进行分析,探索各球队本赛季的成绩能否代表其真实实力,为球队实力排名建立新的评价体系,对球队赛前科学有效的训练控制,提高球队比赛成绩提供科学的理论依据。  相似文献   

Understanding variation in classroom quality within early childhood centers: Evidence from Colorado's quality rating and improvement system   总被引：1，自引：0，他引：1  

Lynn A. Karoly  Gail L. Zellman  Michal Perlman 《Early childhood research quarterly》2013

This study examines variability in quality across classrooms within early childhood centers and its implications for how quality rating systems (QRSs) capture center-level quality. We used data collected for administrative purposes by Qualistar Colorado which includes the environmental rating scale (ERS) collected in all classrooms in the 433 centers participating in Colorado's QRS between 2008 and 2010. We conducted variance components analysis for the ERS and found that between 26% and 28% of the variation in quality captured by the ERS occurred across classrooms within the same center serving children in the same age range. This finding reveals that capturing center-level quality based on average ERS will often miss important within-center quality differences and points to the merits of using “no score below” rules along with rating tier cutpoints in determining center-level ERS. Most QRSs assess center-level quality for a randomly selected subset of classrooms. To test the implications of cross-classroom quality variation for this practice, we simulated four classroom selection strategies in current use: selecting 50% of the rooms, 33% of the rooms, two rooms, or one room. In general, the larger the share of classrooms measured under a selection rule, the lower the chance that a center's rating tier will be misclassified. The error rates under each selection rule also depend on the extent of cross-classroom quality variability, how centers are distributed by size, and the QRS structure. QRS designers, therefore, need to consider the tradeoff between the costs of measuring more classrooms in each center versus the costs of misclassifying centers. The paper quantifies the magnitude of these tradeoffs using the Colorado data and two illustrative QRSs. The implications of our findings for QRS designers, parents, and other stakeholders are discussed.  相似文献   

基于知识图谱的专利研究特点剖析——图情领域的视角     

洪凌子  黄鹏  黄国彬  丁芬芬 《情报杂志》2013,(1):42-49,9

选取了SCI和CSSCI收录的图书情报领域对专利研究的期刊论文,从文献数量上分析出文献发表量有增加的趋势;通过高频关键词、共现关键词及关键词的主题聚类分析,研究了图书情报领域学者在SCI与CSSCI来源期刊上发表的有关专利研究论文的合作特征与主题分布。  相似文献   

Effects of competition level on the centre forward role of men's water polo     

Corrado Lupo  Carlo Minganti  Cristina Cortis  Fabrizio Perroni  Laura Capranica  Antonio Tessitore 《Journal of sports sciences》2013,31(9):889-897

Abstract

This study aimed to compare specific technical and tactical indicators of the team and centre forward role of Euro League, and Italian Serie A1, Serie A2, and Serie B men's water polo club competitions. A notational analysis was performed on 21 water polo matches to evaluate the occurrence of technical and tactical team and centre forward indicators, highlighting differences among championships according to chi-square analyses. Differences emerged for Counterattack (P < 0.001) and Power-Play (P < 0.001) possessions, Even (P < 0.001; Euro League: 3 ± 1, Serie A1: 3 ± 2, Serie A2: 3 ± 2, Serie B: 6 ± 4) and Power-Play (P = 0.001) goals, and exclusions and penalties (P = 0.008) of the team during Even possessions. Relatively to the role analyses, effects emerged for perimeter players playing events (P = 0.049), as well as for centre forwards' goals (P = 0.007) and exclusions and penalties (P < 0.001; Euro League: 8 ± 1, Serie A1: 6 ± 2, Serie A2: 6 ± 2, Serie B: 3 ± 2) occurring at the end of Even possessions. Therefore, in Euro League, and Italian Serie A1 and Serie A2, teams perform a high occurrence of Power-Play possessions following up an exclusion, especially achieved by the centre forward during Even possessions, while, in Italian Serie B, goals were mostly scored during Even possessions, with a relevant contribution from the centre forward role.  相似文献   

The effect of playing tactics and situational variables on achieving score-box possessions in a professional soccer team     

Joaquin Lago-Ballesteros  Ezequiel Rey 《Journal of sports sciences》2013,31(14):1455-1461

Abstract

The aim of this study was to analyse the influence of playing tactics, opponent interaction and situational variables on achieving score-box possessions in professional soccer. The sample was constituted by 908 possessions obtained by a team from the Spanish soccer league in 12 matches played during the 2009–2010 season. Multidimensional qualitative data obtained from 12 ordered categorical variables were used. Sampled matches were registered by the AMISCO PRO^® system. Data were analysed using chi-square analysis and multiple logistic regression analysis. Of 908 possessions, 303 (33.4%) produced score-box possessions, 477 (52.5%) achieved progression and 128 (14.1%) failed to reach any sort of progression. Multiple logistic regression showed that, for the main variable “team possession type”, direct attacks and counterattacks were three times more effective than elaborate attacks for producing a score-box possession (P < 0.05). Team possession originating from the middle zones and playing against less than six defending players (P < 0.001) registered a higher success than those started in the defensive zone with a balanced defence. When the team was drawing or winning, the probability of reaching the score-box decreased by 43 and 53 percent, respectively, compared with the losing situation (P < 0.05). Accounting for opponent interactions and situational variables is critical to evaluate the effectiveness of offensive playing tactics on producing score-box possessions.  相似文献   

An objective method for depicting team performance in elite professional rugby union     

Nicholas M. P. Jones  Nic James  Stephen D. Mellalieu 《Journal of sports sciences》2013,31(7):691-700

Abstract

Using a two-study approach, we examined a methodology for objectively depicting team performance and form in a professional rugby union side. Study 1 developed standardized indicators to examine a team's performance in a single match relative to their previous matches over a domestic season via a performance report and form chart. This resulted in standardized performance indicators that provided instant and coherent feedback on the team's performance relative to previous standards. Study 2 then utilized this methodology to compare a match between two professional sides, played the following season, to assess the extent to which the performance by one team affected that of the other. Comparison of the two teams' performances, for the match they played against each other, identified a drop in relative performance (against previous standards) for both teams on the same performance indicators. This appeared to be due to the match being a close, hard-fought contest particularly in the tackle and around the gain-line. The findings of the two studies suggest an accurate and viable methodology for depicting team performance that is superior to the global measures previously adopted. Presenting teams' current standardized performances (i.e. form) on a single visual scale also has utility for coaches within an applied setting. Future research should further investigate the effect of one team's performance on another through both individual and team outcomes.  相似文献