以新生入学指导与服务促高校学生事务管理

新生入学指导与服务是高校学生事务管理的首要环节,做好新生入学的指导与服务,对做好整个学生工作有着重要的指导意义。本文着重讨论新生入学指导与服务的需求分析、内容和方法。     

基于MATLAB的机械优化设计

通过实例详细介绍了MATLAB优化工具箱在机械优化设计中的应用，并与其它文献的结果进行比较，表明本算法较优。     

Seasoned Equity Issues in a Closely Held Market: Evidence from France

This paper examines seasoned equity offerings in France.Even though a rights offering is the primary flotation method, French companies are increasingly usingthe relatively expensive public offering method. We show that the market reaction to the announcementof seasoned equity issues is significantly negative for rights issues and insignificantly negative forpublic offerings. Our results suggest that the adverse selection effect is greater for rights issues thanfor public offerings, due to stronger underwriter certification for the public offerings. We find that theshare price effect is positively related to blockholders take-up renouncements for firms with priorconcentrated ownership. For these firms, the favourable ownership dispersion effect offsets the adverse selection effect.     

基于模糊控制的三相异步电动机的软起动系统

本系统主要通过对模糊控制器的设计 ,将异步电动机的起动电流既限制在了一定的范围内 ,又可得到较大的起动力矩。由于又采用了参数自调整作为辅助控制 ,不但改善了起动时的动态性能 ,而且改善了稳定运行时的静态性能     

A Semiparametric Method for Valuing Residential Locations: Application to Automated Valuation

This paper is motivated by automated valuation systems, which would benefit from an ability to estimate spatial variation in location value. It develops theory for the local regression model (LRM), a semiparametric approach to estimating a location value surface. There are two parts to the LRM: (1) an ordinary least square (OLS) model to hold constant for interior square footage, land area, bathrooms, and other structural characteristics; and (2) a non-parametric smoother (local polynomial regression, LPR) which calculates location value as a function of latitude and longitude. Several methods are used to consistently estimate both parts of the model. The LRM was fit to geocoded hedonic sales data for six towns in the suburbs of Boston, MA. The estimates yield substantial, significant and plausible spatial patterns in location values. Using the LRM as an exploratory tool, local peaks and valleys in location value identified by the model are close to points identified by the tax assessor, and they are shown to add to the explanatory power of an OLS model. Out-of-sample MSE shows that the LRM with a first-degree polynomial (local linear smoothing) is somewhat better than polynomials of degree zero or degree two. Future applications might use degree zero (the well-known NW estimator) because this is available in popular commercial software. The optimized LRM reduces MSE from the OLS model by between 5 percent and 11 percent while adding information on statistically significant variations in location value.     

An optimization approach to business buyer choice sets: How many suppliers should be included?

In many new or repeat purchasing situations, business buyers must decide how many suppliers to consider (a “choice set”) in determining which supplier(s) to actually buy from or contract with. This paper develops an optimization approach to determining the size of the choice set, taking into consideration buyer utility and search and evaluation costs. A theoretical model is developed for both one-time and repeat purchase situations. The model is estimated using empirical data received from bids received for procurement auctions. In these auctions, suppliers provide bids for steel pipe based on two product attributes (price and delivery time). Model sensitivity to small changes in parameters is also tested.     

Sharing my way to success: A case study on developing entrepreneurial ventures using social capital in an OSS community

While Open Source Software (OSS) communities provide opportunities for knowledge creation, we have a limited understanding of how entrepreneurs leverage OSS communities for their entrepreneurial ventures. Using social capital theory in a mixed methods case study, we compare entrepreneur and non-entrepreneur behaviors to investigate how entrepreneurs build social capital within an OSS community. This study shows that entrepreneurs differentiate themselves from non-entrepreneurs by focusing on cognitive and relational capital building activities, which in return makes it possible for them to leverage their social capital to influence and shape the environment in which they are operating. Our findings suggest that entrepreneurs strategically select which activities within the community to expend their limited resources on (e.g., developing code over participating in email conversations) and build their social capital more through their actions than through their words (e.g., showing their commitment to the community through code commits, bug fixes, and documentation). Given the liabilities of newness and smallness as well as other challenges faced by entrepreneurs, applying an open innovation strategy in OSS communities could be one approach where entrepreneurs, by developing and freely revealing their intellectual property to the community, share their way to success via OSS-infused entrepreneurial business ventures.     

基于多源数据融合的地表覆盖数据重建研究进展综述

地表覆盖数据对于全球环境变化、生物多样性和发展政策制定有着重要意义。遥感已成为获取地表覆盖数据的重要手段。而目前的地表覆盖数据产品,如Globe Land30、FROM-GLC、MODIS Collection5、MODIS Cropland、Glob Cover、GLC2000等,存在数据精度不高、数据间一致性较差、与统计数据差异较大等问题。因此,基于多源数据融合的数据重建方法成为目前研究中的热点问题。文章检索了近10年关于多源数据融合在地表覆盖数据重建中的应用的相关文献,概括了多源数据在数据重建中的应用现状,并对基于多源数据融合的地表覆盖数据重建方法进行了归纳总结,重点评述了不同方法的特点及应用情况,阐明了各种方法的优势与不足,同时对存在的问题进行探讨并展望了未来基于多源数据融合的地表覆盖数据重建研究的发展方向。基于多源数据融合的数据重建方法包括基于多源遥感数据融合法以及基于多源遥感和非遥感数据融合法。该文在对基于多源遥感数据融合的数据重建方法进行论述时,主要讨论了其中应用最广泛的两种融合方法:基于数据一致性的融合法和基于回归分析的融合法。对于其他基于多源遥感数据融合的数据重建方法,如基于D-S证据理论融合法、基于数据集成融合法、基于统计模型融合法,也列举了最具代表性的相关文献进行论述。在对基于遥感数据和非遥感数据融合的数据重建方法进行论述时,主要讨论了其3种空间分配方法:完全依赖法、部分依赖法、动态依赖法。在对目前研究进行探讨的过程中,该文对其研究区域、数据源、地表覆盖类型、空间分辨率、融合方法和文献来源进行总结分析,并重点就融合方法展开讨论。围绕各种融合方法在数据重建中的运用,该文归纳出目前研究中存在的主要问题:研究对象和区域上的不足,研究区多为全球及欧美,其他区域的研究过少,研究对象多为所有地表覆盖类型和森林,对耕地和草地的研究过少;融合算法上的不足、重建结果精度上的不足。最后,指出基于多源数据融合的数据重建方法未来的发展方向,即综合运用两类方法,得到具有详细完整空间信息的长时间序列的地表覆盖数据集。     

Implied integrated variance and hedging

If the volatility is stochastic, stock price returns and European option prices depend on the time average of the variance, i.e. the integrated variance, not on the path of the volatility. Applying a Bayesian statistical approach, we compute a forward-looking estimate of this variance, an option-implied integrated variance. Simultaneously, we obtain estimates of the correlation coefficient between stock price and volatility shocks, and of the parameters of the volatility process. Due to the convexity of the Black–Scholes formula with respect to the volatility, pricing and hedging with Black–Scholes-type formulas and the implied volatility often lead to inaccuracies if the volatility is stochastic. Theoretically, this problem can be avoided by using Hull–White-type option pricing and hedging formulas and the integrated variance. We use the implied integrated variance and Hull–White-type formulas to hedge European options and certain volatility derivatives.     

农业绿色发展的内涵与评价研究

[目的]推进农业绿色发展是农业发展观的一场深刻革命,关键在体制机制创新,建立一套适用于全国不同地区农业绿色发展评价的指标体系与评价办法,从而增强各地农业绿色发展责任意识,为推进农业绿色发展提供方向指导和决策参考。[方法]通过对国内外相关研究的梳理分析,对新时代我国农业绿色发展的内涵进行界定,进一步明确农业绿色发展的评价思路。[结果]在此基础上,构建包括4个一级指标、19个二级指标的农业绿色发展定量评价体系与由6个一级指标、15个二级指标构成的农业绿色发展定性评价指标体系,提出了归一化法和标准化系数法等评价方法。[结论]政府要加快建立完善农业绿色发展组织体系、领导干部农业生态资源离任审计以及农业绿色发展考核奖惩制度等制度体系,进一步强化农业生态资源数据采集与统计体系建设,加快更新农业资源环境统计条目,为农业绿色发展评价提供数据支撑。