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1.
Multinomial logit (also termed multi-logit) models permit the analysis of the statistical relation between a categorical response variable and a set of explicative variables (called covariates or regressors). Although multinomial logit is widely used in both the social and economic sciences, the interpretation of regression coefficients may be tricky, as the effect of covariates on the probability distribution of the response variable is nonconstant and difficult to quantify. The ternary plots illustrated in this article aim at facilitating the interpretation of regression coefficients and permit the effect of covariates (either singularly or jointly considered) on the probability distribution of the dependent variable to be quantified. Ternary plots can be drawn both for ordered and for unordered categorical dependent variables, when the number of possible outcomes equals three (trinomial response variable); these plots allow not only to represent the covariate effects over the whole parameter space of the dependent variable but also to compare the covariate effects of any given individual profile. The method is illustrated and discussed through analysis of a dataset concerning the transition of master’s graduates of the University of Trento (Italy) from university to employment.  相似文献   
2.
基于SVM的综合实力评估系统研究   总被引:3,自引:0,他引:3  
简略介绍了支持向量机的基本思想 ,研究其在综合评价中的应用。分析了对大学进行实力评估的过程 ,建立基于SVM的评价系统。比较新评价系统和采用其他方法如PCA (PrincipalComponentAnalysis主元分析 ) ,Fisher等建立的评价系统所分别取得的拟合效果。结果表明 :采用支持向量机设计的评价系统思路清晰 ,操作简单并且能取得更为理想的评估结果。  相似文献   
3.
A hybrid ARIMA and support vector machines model in stock price forecasting   总被引:4,自引:0,他引:4  
Ping-Feng Pai  Chih-Sheng Lin 《Omega》2005,33(6):11489-505
Traditionally, the autoregressive integrated moving average (ARIMA) model has been one of the most widely used linear models in time series forecasting. However, the ARIMA model cannot easily capture the nonlinear patterns. Support vector machines (SVMs), a novel neural network technique, have been successfully applied in solving nonlinear regression estimation problems. Therefore, this investigation proposes a hybrid methodology that exploits the unique strength of the ARIMA model and the SVMs model in forecasting stock prices problems. Real data sets of stock prices were used to examine the forecasting accuracy of the proposed model. The results of computational tests are very promising.  相似文献   
4.
信任对 CSA 经济的可持续至关重要。 文章基于信任建立过程和信任发展的阶段性理论,通过单案例的研究方法探讨如何构建社区支持农业中的消费者信任。 研究结果表明:消费者信任的建立分为初始信任与持续信任两个阶段。 在潜在消费者的初始信任阶段,直接或间接关系、公开的信息、农 场主特征和消费体验会引发消费者的计算过程、转移过程、预测过程、意图过程和能力过程而建立消费 者初始信任。 在会员的持续信任阶段,用户体验和社会联系会引发消费者的预测过程和意图过程而维 持会员对农场的信任。  相似文献   
5.
This paper presents an effective and efficient method for solving a special class of mixed integer fractional programming (FP) problems. We take a classical reformulation approach for continuous FP as a starting point and extend it for solving a more general class of mixed integer (0–1) fractional programming problems.To stress the practical relevance of the research we focus on a real-life application in paper production industry. The constantly advancing physical knowledge of large scale pulp and paper production did have a substantial impact on an existing DSS in which mixed integer (0–1) fractional programming is introduced. We show that the motivation to solve a real-life fractional programming problem can provide the basis for a new approach in a new context that has an added value of its own, even outside the given application area. We describe the main characteristics of the DSS, the necessity to develop a non-iterative solution procedure and demonstrate both the effectiveness and efficiency of the proposed approach from practical data sets.  相似文献   
6.
We are trapped in two divergent worlds when it comes to global views on homosexuality. There is the liberal world epitomized by Spain and other nations, where homosexuality is increasingly accepted; gays and lesbians are claiming their human rights; and laws are changing to codify that transformation. The second is the extremely anti-gay world symbolized by Africa, the Middle East and parts of Asia, where attitudes are favorable to criminalization. This research explains the “African Gap” in attitudes toward homosexuality in a comparative analysis of six African nations and Argentina and Canada, South and North America's most liberal nations on gay rights. Using Pew's 2015 Spring Global Attitudes Survey data, we find that the major variables have essentially similar effects on opinion in any context. Africa's distinction is explained by its comparatively higher levels of factors such as religion, morality dogma, and low socioeconomic status that generally retard support for homosexuality, at the same time of lower levels of factors such as education, urbanization, and personal liberty that increase gay support. Africa's extreme anti-gay outlook is mutable. Two social forces will facilitate this softening: expansion of liberalizing agents such as education and urbanization, and repositioning away from “traditionalism” toward modernism emphasizing individualism, civil rights, and personal liberties.  相似文献   
7.
丁飞鹏  陈建宝 《统计研究》2019,36(3):113-123
本文将最小二乘支持向量机(LSSVM) 和二次推断函数法(QIF) 相结合,为个体内具有相关结构的固定效应部分线性变系数面板模型提供了一种新的快速估计方法;在一定的正则条件下,论证了参数估计量的渐近正态性和非参数估计量的收敛速度;采用Monte Carlo模拟考察了估计方法在有限样本下的表现并将估计技术应用于现实数据分析。该方法不仅保证了估计的有效性和统计推断力,而且程序运行速度得到较大幅度提升。  相似文献   
8.
Cognitive-behavioural parenting programs provide caregivers with alternative strategies to harsh disciplining practices but the choice of programs that are evidence-based in Australia is limited. Australian community service workers suggest that having a choice of evidence-based programs is important when matching programs to client needs, and that 1-2-3 Magic is a program used widely in Australia despite its small Australian evidence base. The efficacy of the 1-2-3 Magic program has previously been shown in a controlled trial in an Australian university research setting but little is known about its effectiveness in a “real-world” setting. This study examined a three-session group-format of the Australian 1-2-3 Magic & Emotion Coaching program in a typical metropolitan community service setting. Thirty-eight caregivers with children aged 2–6 years reported a significant decrease in disruptive child behaviour (ECBI), permissive parenting (PS), and parental depression and stress (DASS) from pre- to post-intervention, with results maintained at 3-month follow-up. While these findings suggest that a brief 1-2-3 Magic program is beneficial, it is important to note that methodological limitations (intervention-group only study design and possible confounding variables) do not allow ruling out alternative causes for these improvements. Further research will be needed to confirm that this program can generalise to “real-world” settings.  相似文献   
9.
Offshore petroleum industry uses helicopters to transport the employees to and from installations. Takeoff and landing represent a substantial part of the flight risks for passengers. In this paper, we propose and analyze approaches to create a safe flight schedule to perform pickup of employees by several independent flights. Two scenarios are considered. Under the non-split scenario, exactly one visit is allowed to each installation. Under the split scenario, the pickup demand of an installation can be split between several flights. Interesting links between our problem and other problems of combinatorial optimization, e.g., parallel machine scheduling and bin-packing are established. We provide worst-case analysis of the performance of some of our algorithms and report the results of computational experiments conducted on randomly generated instances based on the real sets of installations in the oil fields on the Norwegian continental shelf. This paper is the first attempt to handle takeoff and landing risk in a flight schedule that consists of several flights and lays ground for the study on more advanced and practically relevant models.  相似文献   
10.
Child and family practice is recognised as a field of social work that has become increasingly complex. While evidence is growing in relation to effective supervision, there has been little research about the attributes of an effective supervisor, or the components of effective supervision. This paper reports on research undertaken in Victoria, Australia, which explored practitioners’ and supervisors’ experiences of effective supervision in this field. Data collection involved in-depth interviews with experienced supervisors and supervisees in order to explore the concept of effective supervision from participants’ perspectives. The data were systematically interrogated using a thematic inductive process, designed to enhance the voice of participants in the research. The study findings confirmed the complexity and centrality of the supervisory relationship, with the experience of a safe supervisory relationship proving essential. The importance of contemporary knowledge, leadership skills, and an enabling organisational and community context were also highlighted.  相似文献   
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