Model-based clustering of multivariate skew data with circular components and missing values

Motivated by classification issues that arise in marine studies, we propose a latent-class mixture model for the unsupervised classification of incomplete quadrivariate data with two linear and two circular components. The model integrates bivariate circular densities and bivariate skew normal densities to capture the association between toroidal clusters of bivariate circular observations and planar clusters of bivariate linear observations. Maximum-likelihood estimation of the model is facilitated by an expectation maximization (EM) algorithm that treats unknown class membership and missing values as different sources of incomplete information. The model is exploited on hourly observations of wind speed and direction and wave height and direction to identify a number of sea regimes, which represent specific distributional shapes that the data take under environmental latent conditions.     

我国大学生创业教育问题与对策分析

在总结阐释大学生创业教育本质内涵的基础上,分析了我国大学生创业教育中存在的问题,并有针对性地提出了改进策略与建议,以期对促进我国大学生创业教育的健康发展有所启示。     

女性创业动机变迁与自我发展

选取浙江省杭州市20名创业女性为访谈对象的创业动机变迁研究显示,在2005年之前,女性创业动机以"推式动机"为多,而自2006年始,女性创业动机呈现出以"拉式动机"为主的趋势。这种变化主要与女性受教育程度提高、个性更为独立、追求更为自由的发展空间等相关。女性创业动机的变化趋势,在很大程度上反映了女性自我发展正趋向更高的水平。     

大学生返乡创业生态系统：目标、要素、机理和对策*

创业生态系统从生态系统的视角揭示了创业生态中创业主体、创业要素、创业环境以及各要素之间的相互作用。创业生态系统是一个复杂的自适应系统，其具有复杂的自适应系统的各项特征，从系统的角度来讲，其具有系统的目标、要素、运行机理和系统边界。本文以大学生返乡创业生态系统为例，从系统目标、系统要素和系统的运行机理三个方面立体剖析了创业生态系统的内涵和外延。同时，对大学生返乡创业生态系统的目标设定、大学生返乡创业生态系统各要素的构成以及大学生创业生态系统的运行机理进行了分析，对强化大学生返乡创业生态系统的构建提出了对策建议，为促进大学生返乡创业和乡村振兴提供参考。     

Negotiating Gendered Subjectivity in the Enterprise Culture: Metaphor and Entrepreneurial Discourses

An enterprise culture is one in which ‘certain enterprising qualities — such as self reliance, personal responsibility, boldness and a willingness to take risks in the pursuit of goals — are regarded as human virtues and promoted as such’. Work is not seen as a constraint upon the individual but rather as an opportunity for self‐fulfilment. The pervasiveness of enterprise culture has led to observations that it influences aspects of social life beyond the workplace. However, the kind of self that is imagined in enterprise culture is also a male self, with female entrepreneurship measured against a male norm. In this article, then, we present evidence of metaphor as a strategy for coping with the gendered expectations embodied by life in enterprise culture. We show how metaphor is simultaneously an index of and a resource for understanding gendered subjectivities in enterprise culture.     

Creating the Next Wave of Family Therapy

This article is an exploration of family therapy in Australia based on interviews with seven leading Australian family therapists: Max Cornwell, Carolyn Quadrio, Ron Perry, Laurie MacKinnon, Brian Stagoll, Banu Moloney and Jim Crawley. It explores the attributes and qualities of what makes a good family therapist and seeks to understand how the next generation of therapists can generate a new enthusiasm for family therapy.     

多相感应电机任意非正弦气隙磁密的磁动势分析与应用

多相感应电机转矩密度的提高依赖于非正弦气隙磁密行波的合理构建,由于传统的电流相位、幅值控制策略无 法给出期望的非正弦磁密行波,因此文章研究了控制多相感应电机定子相电流中基波和谐波幅值、相位、频率的大小来 构建期望的气隙磁密波形的方法、首先基于单根载流导体产生的气隙磁动势波形,推导了任意相数、不对称、包含任意 高次谐波电流波形激励的具有典型绕组结构的多相感应电机的磁动势分布表达式。根据以上磁动势分析结论,多相电 机可通过变电流相序变极。针对气隙磁密行波逼近方波波形的案例,根据所提出的磁动势分析方法分析和预测了理想 空载励磁电流的波形。将预测波形和方波供电下的励磁电流波形进行了比较,从FFT分析结果来看,仍需微调各次谐波 电压相位,从而实现各次电流相位完全一致。     

信任对农民创业机会识别的影响

基于信任视角,构建农民创业者信任对创业机会识别的理论分析框架,运用链式多重中介方法,对浙江、安徽、河南和陕西4省880份农民创业者访谈数据进行实证分析,结果发现:信任能显著提高农民创业机会识别;农民创业者信任能通过外部知识获取与创业警觉性对创业机会识别产生间接影响,其作用路径有三条:外部知识获取的部分中介作用、创业警觉性的部分中介作用及外部知识获取与创业警觉性的链式中介作用。因此,政府应完善农民创业相关规章与制度;推进农村文化建设,提高信任水平;增加农民创业知识与技能的供给,培养农民创业者的机会警觉性。     

如何提升大学生的创业能力

本文认为必须采取改进高校硬件设施和改革培养方案等,打造创业人才培养的硬软实力。     

薛定谔创立波动力学的激励机制是“数学美”

诺贝尔奖得主薛定谔是一位集物理学家、哲学家和诗人于一身的全才。他的多才多艺和显赫的业绩，特别是他对数学美的执著追求及其创立的波动力学，不仅对21世纪物理学的发展产生了巨大而深远的影响，而且也为当今推进我国高校实施科学与人文交融的素质教育模式，提供了一个光辉的范例。