Forecasting economic time series using flexible versus fixed specification and linear versus nonlinear econometric models

Nine macroeconomic variables are forecast in a real-time scenario using a variety of flexible specification, fixed specification, linear, and nonlinear econometric models. All models are allowed to evolve through time, and our analysis focuses on model selection and performance. In the context of real-time forecasts, flexible specification models (including linear autoregressive models with exogenous variables and nonlinear artificial neural networks) appear to offer a useful and viable alternative to less flexible fixed specification linear models for a subset of the economic variables which we examine, particularly at forecast horizons greater than 1-step ahead. We speculate that one reason for this result is that the economy is evolving (rather slowly) over time. This feature cannot easily be captured by fixed specification linear models, however, and manifests itself in the form of evolving coefficient estimates. We also provide additional evidence supporting the claim that models which ‘win’ based on one model selection criterion (say a squared error measure) do not necessarily win when an alternative selection criterion is used (say a confusion rate measure), thus highlighting the importance of the particular cost function which is used by forecasters and ‘end-users’ to evaluate their models. A wide variety of different model selection criteria and statistical tests are used to illustrate our findings.     

Unlocking the potential of advanced manufacturing technologies

This research examines whether investments in advanced manufacturing technologies (AMTs) such as flexible manufacturing systems (FMS), computer aided design (CAD), computer aided manufacturing (CAM), robotics, etc., are more likely to lead to improved performance if they are supported by improvements in the manufacturing infrastructure of the company. This question is evaluated using data gathered from 202 manufacturing plants chosen from industries generally considered to have relatively high investments in technology.Multiple item scales are developed and adapted from sources in the literature to measure investments in technology, infrastructure, and the performance of the plant. Evidence supporting the reliability and validity of these scales is provided. Hierarchical regression is used to analyze the relationship between technology, infrastructure, and performance. The results suggest that there is an important interaction between the adoption of advanced manufacturing technologies and investments in infrastructure. Firms that invest in both AMTs and infrastructure perform better than firms which only invest in one or the other. Separate analyses on sub-samples of firms with the highest and lowest investments in AMTs show that infrastructural investments have a stronger relationship with performance in the high investment group. Thus, the data indicate that infrastructural investments provide a key to unlocking the potential of advanced manufacturing technologies.     

我国企业国际科技合作现状及对策研究

文章从经济和科技全球化背景下企业国际科技合作的战略地位分析入手,介绍了我国企业国际科技合作概况,重点分析了企业对外科技合作存在的主要问题,提出了推进企业国际科技合作发展的8点对策建议。     

企业技术创新与研究开发探讨

在社会主义市场经济环境中，企业的技术创新和技术研发被提升到一个从未有过的高度，这两个词汇也频频被知识经济下的各种传媒所引用。作者认为，如果对二者没有一个清晰的概念，忽略了它们本质上的差异，那么对“科学技术是第一生产力”就不会有深刻的理解，也无法说清技术对经济的影响，思想的混乱将会导致企业决策和行动的失误。本文结合企业的实际情况，就技术研发与技术创新的表现以及对企业发展的作用和影响，进行分析和探讨。     

Remote control and maintenance outsourcing networks and its applications in supply chain management

The paper analyzes the impact of e-business technologies on maintenance management and supply chain operations. The aim of this work is to investigate the network organization level of supply chains in case of remote maintenance application and to understand how maintenance policies are coupled with information technology (IT) solutions. To this purpose two literature reviews are presented: firstly, on the supply chain and network integration, and then on the evolution of maintenance using information technology. Following this, the paper present four specific industrial case-studies of eMRO network organisation. They have been chosen as reference models from a set of practical applications and pilot tests performed by the authors in different production sectors in the last 5 years. Technology complexity environments, maintenance outsourcing level, and supply chain integration context are discussed for each case-studies with particular regards to the profitable forms of collaboration provided by the introduction of IT and the Web. This analysis work toward the development of a framework useful to: (1) classify different e-maintenance systems and understand the relationships between the different members of the network, and (2) identify the variables which can influence the introduction and development of the systems.     

大型现浇混凝土工程给水管道预埋问题的研究

文章对大型混凝土现浇工程中给水管道预埋应注意的几个问题进行了详细的分析和总结,为推广应用混凝土现浇工程管道同步预埋提供了提高工程质量、加快施工进度的指导方法。     

基于RFID技术的电子商务物流体系研究

指出了基于RFID技术的电子商务物流体系的几大功能,论述了其体系结构及路线设计。     

基于无线技术的仓储拣选作业流程再造方案分析

对传统的仓储拣选作业流程进行了研究分析,提出了基于无线技术的仓储拣选作业流程再造方案,并对两者进行了对比分析,阐述了再造后的拣选作业流程采用无线技术及其相关技术后的诸多优点及发展前景.     

灰色理论在城市总体规划中的应用研究

在编制城市总体规划时收集的资料和信息往往是不完全和不对称的，很多数据需要通过科学的理论去建立合理的模型来推算，本文采用灰色理论建模，以GDP预测为例详细说明了灰色预测模型GM（1，1）的建模过程。该模型对于预测城市总体规划中水文、人口、用地规模、城市化水平、交通运输发展、公共交通以及客货运量等具有普遍指导意义。     

对我国技术引进消化吸收与创新问题的思考

技术引进是迅速提升我国技术水平的有效捷径,本文在分析必须重视引进技术消化吸收和创新的基础上,分析了我国农业引进技术消化吸收和创新的主要制约因素,提出了加强引进技术消化吸收和创新工作的对策.