时序分析在地下洞室变形监测数据处理中的应用

时序分析法是广泛应用于多领域的统计分析方法,在岩土工程数值分析当中也有广泛应用,SAS/ETS(Ti me Series Forecasting)时序分析系统是一种智能化时序分析工具,本文运用SAS数据挖掘工具中时序分析组件对某水电站地下引水发电系统原位监控位移时间序列进行时序预测分析。实践表明,SAS/ETS时序分析方法基本能反映出蕴涵在位移序列中的岩体变形规律,预测结果与实测结果一致,可以运用于工程实践。     

Residential Asking Rents and Time on the Market

Landlords offering a house in the rental market face a difficult strategic pricing decision. The revenue maximizing decision for the landlord involves a tradeoff between the rental rate and time on the market. Because the turnover of renters is higher than owners, and because the landlord must bear some carrying costs on a vacant house, pricing the rent too high may decrease revenue due to a higher vacancy period and pricing it too low may reduce the revenue when occupied. While there is substantial research on the relationship between listed prices and time on the market for freehold interests, this is the first study to provide empirical evidence on the relationship between asking rent, contract rent and time on the market for single family residential rental (leasehold) property interests. We present two models; a rental price model and a duration model for time-on-the market. Using data from the Dallas–Fort Worth area we find that landlords who set a lower asking rent relative to predicted rent can expect a shorter marketing period for their properties. The results also indicate that overpricing the asking rent and then lowering it at a later date leads to a longer marketing time (after the reset) and often a lower rent. These finding are reasonably robust for low-, mid-, and higher-valued rental properties.

合同环境下优化路桥项目施工总工期之方法探讨

在合同环境下,针对某一路桥工程,在一定资源的约束下,可以通过施工作业方式的选择、施工段的排序、施工段数的合理确定、项目总成本和质量控制及经理人素质的提高等方法来进一步缩短和优化路桥项目施工总工期。     

采用复合学习时间的复杂任务知识量测度

在总结知识量测度4类研究的基础上,指出其知识量计量原理对知识量测度结果影响的效度、信度与可比性。进而,依据知识方程和发生认识论描述了采用复合学习时间进行知识量（难度）测量的计量原理。然后,基于知识表达系统构建了知识量测度模型,探讨了有别于传统知识量测度的方法。最后,结合任务知识量测度进行了算例说明。     

国家创新体系结构比较：理论与实践双维视角

系统、直观的创新体系结构是研究国家创新体系的基础,体系中各创新要素功能定位、互动关系是分析国家创新体系运行机制的关键。通过理论分析和国际实践,提炼国家创新体系结构类型,提出“三元串联协同”和“三元并联互动”两种不同的结构框架,并进行对比研究。结果发现：两种结构不分优劣,不同结构中创新主体相同且宏观创新逻辑一致,但是创新链条数量及功能不同,对创新辅体的倚重度也不同;美国、德国等更接近“三元并联互动”体系;瑞典、中国等更接近“三元串联协同”体系;提升创新体系效能,解决“卡脖子”难题,需要优化当前创新体系结构或促进创新体系结构转型。     

Temporal variance of revealed preference on-street parking price elasticity

This paper utilises revealed-preference parking trend data from parking meters ex ante and ex post of a general 50% price increase in the hourly cost of on-street parking to estimate the on-street parking price elasticity of demand in an area of Dublin, Ireland. Estimates are presented for the aggregate price elasticity of demand level and individual estimates for specific time periods and days of the week. In terms of reduced parking frequency, the average price elasticity of demand reported is −0.29. Daily average estimates are consistent, with one notable exception being Thursday, a ‘late night shopping’ day for which a lower price sensitivity is reported. Morning periods are also shown to be more responsive than other time periods in the test area, indicating some potential for influencing morning inbound peak traffic levels.     

Gender,Low-Paid Status,and Time Poverty in Urban China

ABSTRACT

Using synthetic data from the 2008 China Time Use Survey (CTUS) and the 2008 China Household Income Project (CHIP), this study estimates time-poverty rates and compares the profiles of time-poor men and women workers in urban China. In line with previous research, time poverty is defined as a lack of enough time for rest and leisure. Three time-poverty measures are adopted. By all three measures, women paid workers and low-paid workers account for a disproportionate share of the time poor. Regression analysis further shows that, other things being equal, workers who are women, low-paid, married, and who live with children or the elderly in counties with higher overtime rates and lower minimum wage standards are more likely to be time poor. Simulations indicate that enforcing working time regulations and raising minimum wage standards could be effective for reducing time poverty.     

专利市场化视角下校企发明专利维持时间影响因素比较研究

专利市场化水平通过对专利权人预期收益率的影响与专利维持时间产生联系。对高校和企业发明专利维持时间及其影响因素进行比较,可为提升高校专利市场化水平提供借鉴。从专利市场化视角出发,以华为和华南理工大学（以下简称“华工”）为例,运用回归分析方法对发明专利维持时间影响因素进行研究。结果发现,华为发明专利维持时间较长,且在审查时间、发明人数和权利要求数方面存在较大差异;各自变量对二者发明专利维持时间的解释力度亦有区别。为提升高校专利市场化水平,提出应强化知识产权创造市场导向、优化发明专利性质布局、强化发明专利专业属性、促进校企科研合作等合理化建议。     

Quantile cointegrating regression

Quantile regression has important applications in risk management, portfolio optimization, and asset pricing. The current paper studies estimation, inference and financial applications of quantile regression with cointegrated time series. In addition, a new cointegration model with quantile-varying coefficients is proposed. In the proposed model, the value of cointegrating coefficients may be affected by the shocks and thus may vary over the innovation quantile. The proposed model may be viewed as a stochastic cointegration model which includes the conventional cointegration model as a special case. It also provides a useful complement to cointegration models with (G)ARCH effects. Asymptotic properties of the proposed model and limiting distribution of the cointegrating regression quantiles are derived. In the presence of endogenous regressors, fully-modified quantile regression estimators and augmented quantile cointegrating regression are proposed to remove the second order bias and nuisance parameters. Regression Wald tests are constructed based on the fully modified quantile regression estimators. An empirical application to stock index data highlights the potential of the proposed method.     

Consistent estimation of a general nonparametric regression function in time series

We propose an estimator of the conditional distribution of X_t|X_t−1,X_t−2,…, and the corresponding regression function , where the conditioning set is of infinite order. We establish consistency of our estimator under stationarity and ergodicity conditions plus a mild smoothness condition.