共享经济可持续性评价：社会感知与客观绩效     

董晓松  霍依凡  赵星 《科研管理》2023,44(1):79-88

共享经济行业可持续性评价的社会感知和客观绩效不一致将造成认知错位、投资误判和政策失效等结果。本文在线挖掘2017—2019年我国主要社交媒体上29 771条文本信息，并收集行业统计数据，综合测度共享经济行业的可持续性并比较其差异。研究发现：社会公众并不认为共享经济行业具有显著的总体可持续性，而且行业实际绩效展现的可持续性与社会大众认知截然不同。进一步发现：受限于主观认知能力，社会公众认为共享经济可持续性主要来自可观察到的行业外部经济和外部生态等维度，但客观绩效表明共享经济行业内部的经济和外部的技术优势才是其可持续性的重要支撑。此外，二者评价的差异在住宿与医疗等产能共享内部过程不易被大众观察的行业中最为突出。  相似文献   

睡美人文献识别方法研究进展     

宗张建 《图书情报工作》2019,63(16):132-142

[目的/意义]睡美人文献是一类蕴藏着巨大科学价值的文献。对国内外睡美人文献识别方法的相关研究成果进行总结与梳理，形成比较完整的综述内容，为国内该领域研究提供参考与借鉴。[方法/过程]按方法属性将识别方法总结为4类，概括各识别方法的基本思路、识别标准、优点及局限性，并参照睡美人文献识别方法的4条原则进行对比，指出各识别方法的适用范围。[结果/结论]睡美人文献识别方法已由单一逐渐丰富，从主观参数向客观指标演变，从单一引文曲线向多种形式曲线并用发展。未来睡美人文献识别研究可从睡眠深度标准再定义、识别方法再组合上深入。此外，还需重视睡美人文献的定性研究和识别方法的验证性研究，重视睡美人引文价值的测度以及预测性研究。  相似文献   

Is academic tracking related to gains in learning competence? Using propensity score matching and differential item change functioning analysis for better understanding of tracking implications     

《Learning and Instruction》2020

This study analyzes gains in cognitive components of learning competence with respect to cohorts based on ability tracking in a Czech longitudinal study. Propensity score matching is used to form parallelized samples of academic and non-academic track students and to eliminate the effect of selective school intake. We applied regression models on the total scores to test for the overall track effect. Furthermore, we analyze scores and gains on the subscores and check for differential item functioning in Grade 6 and in change to Grade 9. While after 3 years, no significant difference between the two tracks was apparent in the total learning competence score, we did, however, find significant differences in some subscores and in the functioning of some items. We argue that item-level analysis is important for deeper understanding of the tracking implications and may provide the basis for more precise evidence-based decisions regarding the tracking policy.  相似文献   

基于NSGAⅡ的带时间窗生鲜品配送路径优化     

李善俊  陈淮莉 《上海海事大学学报》2020,41(2):58-64

考虑到生鲜品的易腐性、高时效性和对运输环境要求高的特点,为减少生鲜品配送企业的配送成本,提高客户满意度,在车辆载重、时间窗、生鲜品保质期等约束条件下,提出将配送总成本最小化和生鲜品新鲜度最大化的多目标车辆路径优化模型。利用改进的非支配排序遗传算法(non-dominated sorting genetic algorithmⅡ,NSGAⅡ)对模型进行求解。求出满足配送总成本最小和生鲜品新鲜度最大的相对较优解,证明模型的有效性。该模型在大规模配送和客户地理位置分布较为分散的情况下,对生鲜品新鲜度的优化较为明显。  相似文献   

Difference score reliabilities within the RIAS-2 and WISC-V     

Ryan L. Farmer  Samuel Y. Kim 《Psychology in the schools》2020,57(8):1273-1288

Many prominent intelligence tests (e.g., Wechsler Intelligence Scale for Children, Fifth Edition [WISC-V] and Reynolds Intellectual Abilities Scale, Second Edition [RIAS-2]) offer methods for computing subtest- and composite-level difference scores. This study uses data provided in the technical manual of the WISC-V and RIAS-2 to calculate reliability coefficients for difference scores. Subtest-level difference score reliabilities range from 0.59 to 0.99 for the RIAS-2 and from 0.53 to 0.87 for the WISC-V. Composite-level difference score reliabilities generally range from 0.23 to 0.95 for the RIAS-2 and from 0.36 to 0.87 for the WISC-V. Emphasis is placed on comparisons recommended by test publishers and a discussion of minimum requirements for interpretation of differences scores is provided.  相似文献   

现代科学体系的立体结构:一体两翼——关于“科学分类”问题的新探讨   总被引：6，自引：1，他引：6  

陈文化  胡桂香  李迎春 《科学学研究》2002,20(6):566-570

本文在总结前人研究工作的基础上 ,以自然—人—社会的演化次序为客观基础 ,将科学分为自然科学、人文科学和社会科学三大门类 ,并构建了现代科学体系———以人文科学为主体、自然科学和社会科学为两翼的立体结构。同时也论证了人文科学的性质、地位和作用 ,以及科学融为一体等问题。  相似文献   

中国企业跨国并购提升了其研发能力吗?——来自“一带一路”沿线国家的证据          下载免费PDF全文

周晶晶  蒋薇薇  赵增耀 《科研管理》2019,40(10):37-47

基于2001-2014年中国企业对“一带一路”沿线国家海外并购数据，利用PSM方法研究了跨国并购对母公司研发创新的影响。结果表明：总体上来看，中国企业对“一带一路”国家的跨国并购显著提升了其研发水平；相比较于劳动密集型产业，资本密集型产业对资本要素和研发创新技术具有较强的敏感性，跨国并购对其研发创新的影响更明显；相比较于东部地区，由于中西部地区企业创新能力较低且多以要素密集型为主，跨国并购对中西部地区跨国企业研发创新的影响较弱。此外，在考虑目标企业所在国家（地区）的地理分布和创新能力因素时发现，跨国并购对母公司研发创新的提升效用随着目标企业所在国家创新能力的减弱而下降。最后，本文实证研究的基础上提出了相应的对策建议。  相似文献   

Time spent on the Internet by multicultural adolescents in Korea     

Yangmi Lim 《Asia Pacific Journal of Education》2017,37(1):55-68

This study analysed The 8th Online Survey of Adolescent Health and Behaviour in 2012, which is a government-approved statistical survey of Internet use and patterns in Korea. We conducted a propensity score matching (PSM) to control for economic status differences between monocultural and multicultural families and an ANOVA to estimate the effects of multicultural family status, adolescents’ gender, school grades, locality, and parents’ academic background on adolescents’ Internet use (for studying and entertainment). The study revealed the following: with regard to Internet use patterns, adolescents from both monocultural and multicultural families selected gaming as their first choice, followed by studying and data searching. Furthermore, main and interaction effects of independent variables on adolescents’ time spent on the Internet for studying were not significant. However, the interaction effects of multicultural family status and mothers’ academic background on adolescents’ time spent on the Internet for entertainment were statistically significant. Specifically, adolescents’ time spent on the Internet for entertainment was higher in multicultural families with mothers whose education level was lower than middle school. Finally, we suggested that the government should provide full support to less educated mothers in multicultural families for effectively and constructively controlling their children’s Internet use and teaching it to them.  相似文献   

论"雨"意象的客观物象群及其审美角度     

王科瑛 《湖南城市学院学报》2007,28(6):38-41

雨意象是中国古典诗词中的经典意象。诗人们用情感的链条将"雨"意象与客观物象组合,从视觉和听觉的角度展现雨的不同审美意境,借"雨"这一感性形象,传达了世事的伤感、离别的悲怨及相思的凄苦等种种人生感触。  相似文献   

对五年制高职教育的几点思考     

石骏 《温州职业技术学院学报》2005,5(4):54-56

在五年制高职教育实践中，在培养目标的正确定位、课程体系的科学构建、实践性教学特色的创建等方面存在许多值得认真思索的问题，需要进一步探讨，并寻求解决问题的方法。  相似文献