Advances in forecasting with neural networks? Empirical evidence from the NN3 competition on time series prediction

This paper reports the results of the NN3 competition, which is a replication of the M3 competition with an extension of the competition towards neural network (NN) and computational intelligence (CI) methods, in order to assess what progress has been made in the 10 years since the M3 competition. Two masked subsets of the M3 monthly industry data, containing 111 and 11 empirical time series respectively, were chosen, controlling for multiple data conditions of time series length (short/long), data patterns (seasonal/non-seasonal) and forecasting horizons (short/medium/long). The relative forecasting accuracy was assessed using the metrics from the M3, together with later extensions of scaled measures, and non-parametric statistical tests. The NN3 competition attracted 59 submissions from NN, CI and statistics, making it the largest CI competition on time series data. Its main findings include: (a) only one NN outperformed the damped trend using the sMAPE, but more contenders outperformed the AutomatANN of the M3; (b) ensembles of CI approaches performed very well, better than combinations of statistical methods; (c) a novel, complex statistical method outperformed all statistical and CI benchmarks; and (d) for the most difficult subset of short and seasonal series, a methodology employing echo state neural networks outperformed all others. The NN3 results highlight the ability of NN to handle complex data, including short and seasonal time series, beyond prior expectations, and thus identify multiple avenues for future research.     

Gender gaps across the earnings distribution for full-time employees in Britain: Allowing for sample selection

This paper investigates gender differences across the log wage distributions of British employees working full-time in 2005. The raw gender wage gap shows a tendency to increase across the distribution with a glass ceiling effect indicated. A strong relationship between high skilled, white-collar occupations and carrying out managerial duties with the glass ceiling effect is indicated in the data. After allowing for positive selection into full-time employment by British women, a substantially larger gender earning gap is found: the selection corrected gender wage gap is close to twice the raw gap across most of the earnings distribution. This selection corrected gap is found to be predominantly related to women receiving lower rewards for their characteristics than men. Indeed, the results suggest the gender earnings gap would all but disappear across the earnings distribution if women working full-time received the same returns to their characteristics as men working full-time in Britain do.     

高校网上招生系统的后续开发与研究

针对目前院校端网上招生录取系统存在的局限性,文章详细介绍了高校网上招生后续开发管理系统的功能,讨论了系统实现中的关键技术及实现方法,指出该系统采用分布式计算技术,建立基于组件的3层C/S模型的体系结构,具有高效性、可伸缩性、开发周期短、安全性高的特点。     

第三方逆向物流信息系统分析与设计

指出信息系统在第三方逆向物流企业中的重要性,分析了第三方逆向物流企业的业务流程和数据传输流程,并提出设计C/S与B/S相混合的第三方逆向物流信息系统的设计方案,并进一步探索了如何通过ASP.NET技术来实现。     

现代物流产业概念内涵和外延的理论研究

以经济学的市场划分、新兴古典经济学分工演进理论和三次产业分类理论为基础,以联合国标准产业分类法和我国《国民经济行业分类》的行业定义、划分原则和规定为标准,同时兼顾现代产业发展趋势-产业融合的特点。依据物流产品特性界定我国现代物流产业狭义和广义概念。     

从供需层面看中国第三方物流问题

随着中国经济的发展，提供第三方物流服务的物流公司纷纷涌现出来。同时，与第三方物流相关的一些问题也随之出现．针对这种情况．我们建立了第三方物流经济模型，从供需层面来分析中国第三方物流中存在的问题．找出问题存在的根本原因，并且对物流企业的建设提出一些建议和解决方案。     

基于协作3PL的供应链运作模式研究

本文在分析了传统供应链物流运作模式为足的基础上，提出了一种基于协作3PL的供应链运作模式和机理．并建立了支持协作3PL供应链运作的信息系统架构.最后，总结了该供应链物流运作模式的优点及注意事项.     

Improving forecasting by estimating time series structural components across multiple frequencies

Identifying the most appropriate time series model to achieve a good forecasting accuracy is a challenging task. We propose a novel algorithm that aims to mitigate the importance of model selection, while increasing the accuracy. Multiple time series are constructed from the original time series, using temporal aggregation. These derivative series highlight different aspects of the original data, as temporal aggregation helps in strengthening or attenuating the signals of different time series components. In each series, the appropriate exponential smoothing method is fitted and its respective time series components are forecast. Subsequently, the time series components from each aggregation level are combined, then used to construct the final forecast. This approach achieves a better estimation of the different time series components, through temporal aggregation, and reduces the importance of model selection through forecast combination. An empirical evaluation of the proposed framework demonstrates significant improvements in forecasting accuracy, especially for long-term forecasts.     

木糖二级生化废水絮凝机理及条件的研究

文章通过选取几种不同的絮凝剂进行研究,来选出对木糖废水处理效果最佳的絮凝剂及其最佳絮凝条件、最佳去除率。从硫酸铝、三氯化铝、PAC、硫酸铁、硫酸亚铁、三氯化铁中选出PAC和Al2(SO4)3,然后针对这两种絮凝剂,研究确定其最佳絮凝条件及最大去除率。PAC的最佳实验条件为:投加量为1.6 g/L,pH=6,快速搅拌时间为30 s,沉降时间为30 min;Al2(SO4)3的最佳实验条件为:投加量为1 g/L,原水pH=6,快速搅拌时间为90 s,沉降时间为30 min。絮凝效果为:COD去除率分别为82.3%和75.38%,色度去除率都达到了90%以上。     

固网运营商的3G发展策略

3G,是英文3rd Generation的缩写,指第三代移动通信技术,相对第一代模拟制式移动通信(1G)和第二代GSM、CDMA等数字移动通信(2G) ,第三代移动通信一般地讲,是指将无线通信与国际互联网等多媒体通信结合的新一代移动通信系统。在中国本土通信市场上, 3G作为下一代商用的移动通信技术越来越近。3G对原有的固网运营商和移动运营商的未来发展的重要性以及对现实业务的冲击,都让运营商不得不高度重视3G市场,并投入大量的精力研究自身的3G发展策略。本文从目前的固网运营商及移动运营商各自的优势,对3G业务、用户市场的粗浅分析中,力求得出固网运营商可能的3G发展策略。