论网络时代学术信息交流的开放存取

分析了网络时代信息用户的需求和信息服务的特点,重点介绍了网络环境下学术信息交流开放存取机制的产生发展过程及其实现方式。     

零价铁法处理垃圾填埋场渗滤液

为解决垃圾渗滤液尤其是回灌后渗滤液存在可生化性差的问题,研究了一种可行的渗滤液物化处理工艺。采用零价铁法工艺,利用废旧铁屑处理渗滤液。实验考察找到了处理效果随铁屑投加量,焦炭投加量、反应时间及pH值变化的规律,并通过正交实验找到了最佳的反应条件组合。实验结果表明:当pH控制在7.4左右,反应时间3 h,铁屑和焦炭投加量分别在175 g.L-1和0.3 g.L-1的时候,能达到60%的化学需氧量去除率。结果表明,零价铁法处理渗滤液效果明显,价格适中,操作简单,应用前景广阔。     

基于生态足迹模型的上海土地利用可持续性调控研究

运用生态足迹模型分析得到了上海市1996-2005年生态足迹的动态变化过程.在此基础上，结合灰色预测方法对近期（2010年）和远期（2020年）的生态足迹及各类用地规模进行了预测，确定了生态环境适宜的上海市土地利用调控指标与优化布局，测算结果将有助于科学制定土地利用总体规划以实现对土地利用的可持续性调控，促进土地利用与经济、人口、资源和环境的协调发展.     

边际电价预测中的误差分析方法研究

针对目前电价预测中误差分析方法繁多、各方法之间可比性差的现象进行分析,总结了电价预测中常用的各种误差分析方法的优缺点,并推荐采用一种新的误差分析方法即中值相对误差来评价各种电价预测方法的精度。实际算例结果表明,该分析方法合理且有效。     

Yield curve forecast combinations based on bond portfolio performance

We propose an economically motivated forecast combination strategy in which model weights are related to portfolio returns obtained by a given forecast model. An empirical application based on an optimal mean–variance bond portfolio problem is used to highlight the advantages of the proposed approach with respect to combination methods based on statistical measures of forecast accuracy. We compute average net excess returns, standard deviation, and the Sharpe ratio of bond portfolios obtained with nine alternative yield curve specifications, as well as with 12 different forecast combination strategies. Return‐based forecast combination schemes clearly outperformed approaches based on statistical measures of forecast accuracy in terms of economic criteria. Moreover, return‐based approaches that dynamically select only the model with highest weight each period and discard all other models delivered even better results, evidencing not only the advantages of trimming forecast combinations but also the ability of the proposed approach to detect best‐performing models. To analyze the robustness of our results, different levels of risk aversion and a different dataset are considered.     

Do IMF fiscal forecasts add value?

We used a panel of 29 advanced and emerging market countries to investigate whether the IMF's World Economic Outlook (WEO) fiscal forecasts add value in terms of forecast accuracy and information content, relative to private sector forecasts (from Consensus Economics). We find that: (i) WEO forecasts are not significantly less accurate than Consensus forecasts; (ii) WEO and Consensus forecasts tend to mutually encompass one another; and (iii) each source of forecasts appears to contain some information that is not embedded in the other source.     

Strategic asset allocation by mixing shrinkage,vine copula and market equilibrium

We propose a new portfolio optimization method combining the merits of the shrinkage estimation, vine copula structure, and Black–Litterman model. It is useful for many investors to satisfy simultaneously the three investment objectives: estimation sensitivity, asymmetric risks appreciation, and portfolio stability. A typical investor with such objectives is a sovereign wealth fund (SWF). We use China's SWF as an example to empirically test the method based on a 15‐asset strategic asset allocation problem. Robustness tests using subsamples not only show the method's overall effectiveness but also manifest that the function of each component is as expected.     

Are household subjective forecasts of personal finances accurate and useful? A directional analysis of the British Household Panel Survey

The purpose of the paper is to analyse the accuracy and usefulness of household subjective forecasts of personal finance. We use non‐parametric directional analysis to assess the subjective forecasts which are based on qualitative judgments. Using the British Household Panel Survey (BHPS) we are able to analyse a large number of individuals over a number of years. We also take into account individual characteristics such as gender, age, education and employment status when assessing their subjective forecasts. The paper extends the existing literature in two ways: the accuracy and usefulness of subjective forecasts, based on directional analysis, are assessed at the household level for the first time. Secondly, we adapt and extend the methods of directional analysis, which are applied to the household panel or longitudinal survey. Copyright © 2008 John Wiley & Sons, Ltd.     

Nowcasting with Google Trends in an Emerging Market

Most economic variables are released with a lag, making it difficult for policy‐makers to make an accurate assessment of current conditions. This paper explores whether observing Internet browsing habits can inform practitioners about aggregate consumer behavior in an emerging market. Using data on Google search queries, we introduce an index of online interest in automobile purchases in Chile and test whether it improves the fit and efficiency of nowcasting models for automobile sales. Despite relatively low rates of Internet usage among the population, we find that models incorporating our Google Trends Automotive Index outperform benchmark specifications in both in‐sample and out‐of‐sample nowcasts, provide substantial gains in information delivery times, and are better at identifying turning points in the sales data. Copyright © 2011 John Wiley & Sons, Ltd.     

A monetary real‐time conditional forecast of euro area inflation

Based on a vector error correction model we produce conditional euro area inflation forecasts. We use real‐time data on M3 and HICP, and include real GPD, the 3‐month EURIBOR and the 10‐year government bond yield as control variables. Real money growth and the term spread enter the system as stationary linear combinations. Missing and outlying values are substituted by model‐based estimates using all available data information. In general, the conditional inflation forecasts are consistent with the European Central Bank's assessment of liquidity conditions for future inflation prospects. The evaluation of inflation forecasts under different monetary scenarios reveals the importance of keeping track of money growth rate in particular at the end of 2005. Copyright © 2009 John Wiley & Sons, Ltd.