首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   38篇
  免费   2篇
管理学   13篇
人口学   3篇
理论方法论   1篇
社会学   14篇
统计学   9篇
  2023年   3篇
  2021年   1篇
  2019年   5篇
  2018年   2篇
  2017年   2篇
  2016年   2篇
  2015年   1篇
  2014年   4篇
  2013年   5篇
  2012年   4篇
  2011年   3篇
  2010年   1篇
  2006年   2篇
  2003年   1篇
  1998年   1篇
  1997年   1篇
  1995年   1篇
  1992年   1篇
排序方式: 共有40条查询结果,搜索用时 15 毫秒
31.
We introduce a new flexible distribution to deal with variables on the unit interval based on a transformation of the sinh–arcsinh distribution, which accommodates different degrees of skewness and kurtosis and becomes an interesting alternative to model this type of data. We also include this new distribution into the generalised additive models for location, scale and shape (GAMLSS) framework in order to develop and fit its regression model. For different parameter settings, some simulations are performed to investigate the behaviour of the estimators. The potentiality of the new regression model is illustrated by means of a real dataset related to the points rate of football teams at the end of a championship from the four most important leagues in the world: Barclays Premier League (England), Bundesliga (Germany), Serie A (Italy) and BBVA league (Spain) during three seasons (2011–2012, 2012–2013 and 2013–2014).  相似文献   
32.
The study objectives were to evaluate the correlates and psychosocial implications of internet gambling among adolescents, as well as the association between internet gambling and problematic internet use. A cross-sectional study design was applied among a random sample (N = 484) of adolescents (71.2% boys; 28.8% girls; mean age ± standard deviation, SD = 14.88 ± 0.55 years). Self-completed questionnaires, including internet gambling practices, internet use characteristics, Young Internet Addiction Test, and Strengths and Difficulties Questionnaire were utilized. The prevalence of internet gambling was 15.1%. Internet gambling was associated with psychosocial maladjustment, including Abnormal Conduct Problems (gender adjusted odds ratio, AOR = 3.83; 95% confidence interval, 95% CI: 1.86–7.92) and Borderline Peer Problems (AOR = 2.04; 95% CI: 1.09–3.85). The likelihood of concomitant problematic internet use was significantly higher among internet gamblers (AOR = 1.81; 95% CI: 1.03–3.19). Multivariate regression analyses indicated that among all characteristics of internet use assessed, utilizing the internet for the purposes of gambling practices was independently associated with problematic internet use among adolescents (AOR = 3.43; 95% CI: 1.40–8.39). Thus, the study findings suggest that adolescents who participate in internet gambling practices are more likely to concomitantly present with problematic internet use.  相似文献   
33.
This study presents the first attempt to develop classification models for the prediction of share repurchase announcements using multicriteria decision aid (MCDA) techniques. We use three samples consisting of 434 UK firms, 330 French firms, and 296 German firms, to develop country-specific models. The MCDA techniques that are applied for the development of the models are the UTilités Additives DIScriminantes (UTADIS) and the ELimination and Choice Expressing REality (ELECTRE) TRI. We adopt a 10-fold cross validation approach, a re-sampling technique that allows us to split the datasets in training and validation sub-samples. Thus, at the first stage of the analysis the aim is the development of a model capable of reproducing the classification of the firms considered in the training samples. Once this stage is completed, the model can be used for the classification of new firms not included in the training samples (i.e. validation stage). The results show that both MCDA models achieve quite satisfactory classification accuracies in the validation sample and they outperform both logistic regression and chance predictions. The developed models could provide the basis for a decision tool for various stakeholders such as managers, shareholders, and investment analysts.  相似文献   
34.
We present results from a cross-sectional study of the entire adolescent student population aged 12–19 of the island of Kos and their parents, on the relationship between their Internet gambling and respective parental practices, including aspects of psychological bonding and online security measures. The sample consisted of 2,017 students (51.8% boys, 48.2% girls). Our results indicate that gender, parenting practices as perceived by the adolescents and distinct patterns of adolescent Internet activities are among the best predictor variables for Internet gambling. Security practices exercised by the parents failed to make an impact on the extent of Internet gambling, demonstrating the need for specific measures to tackle this phenomenon since the provision of simple education on the dangers of the Internet is not sufficient to this regard.  相似文献   
35.
36.
Product recovery operations in reverse supply chains face rapidly changing demand due to the increasing number of product offerings with reduced lifecycles. Therefore, capacity planning becomes a strategic issue of major importance for the profitability of closed‐loop supply chains. This work studies a closed‐loop supply chain with remanufacturing and presents dynamic capacity planning policies developed through the methodology of System Dynamics. The key issue of the paper is how the lifecycles and return patterns of various products affect the optimal policies regarding expansion and contraction of collection and remanufacturing capacities. The model can be used to identify effective policies, to conduct various “what‐if” analyses, and to answer questions about the long‐term profitability of reverse supply chains with remanufacturing. The results of numerical examples with quite different lifecycle and return patterns show how the optimal collection expansion/contraction and remanufacturing contraction policies depend on the lifecycle type and the average usage time of the product, while the remanufacturing capacity expansion policy is not significantly affected by these factors. The results also show that the collection and remanufacturing capacity policies are insensitive to the total product demand. The insensitivity of the optimal policies to total demand is a particularly appealing feature of the proposed model, given the difficulty in obtaining accurate demand forecasts.  相似文献   
37.
In this work we focus on relationships between stationary point process using spectral analysis techniques. The evaluation of these relationships is accomplished with the help of the product ratio of association (PRA), which is based on the cumulant densities of the point processes. The estimation procedure is obtained by smoothing the periodogram statistic, a function of the frequency domain. It is proved that the asymptotic distribution of the square root of the estimated PRA is Normal with a constant variance. Statistical tests for hypotheses concerning the independence of two point processes and the characterization of a Poisson process are proposed. Furthermore, approximate 95% pointwise confidence interval can be obtained for the estimated PRA. These results can be applied on stochastic systems involving as input and output stationary point processes. An illustrative example from the framework of neurophysiology is presented.  相似文献   
38.
This paper compares the standard location-then-pricing Hotelling duopoly with a catalog competition game in which firms simultaneously decide locations and prices. We consider a three-location space and continuous pricing and fully characterize the unique symmetric equilibrium. In both games, firms employ mixed strategies, producing a mainstream product more often than a specialized one. In the catalog game, prices are always above the marginal cost of production, whereas in the sequential model, prices converge to the marginal cost when firms produce the same variety. We experimentally test our theoretical predictions in the laboratory, finding strong evidence in favor of most of them.  相似文献   
39.
We employ quantile regression fixed effects models to estimate the income-pollution relationship on NO x (nitrogen oxide) and SO 2 (sulfur dioxide) using U.S. data. Conditional median results suggest that conditional mean methods provide too optimistic estimates about emissions reduction for NO x , while the opposite is found for SO 2. Deleting outlier states reverses the absence of a turning point for SO 2 in the conditional mean model, while the conditional median model is robust to them. We also document the relationship's sensitivity to including additional covariates for NO x , and undertake simulations to shed light on some estimation issues of the methods employed.  相似文献   
40.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号