OFDM系统的多符号改进算法

针对OFDM训练符号同步算法中存在的大采样数据而导致捕获时间过长的问题。提出了一种多符号改进算法。该算法应用对多个符号等间隔取样并共轭相乘累加的方法，在采用小数目的采样数据时就可以取得较好的性能，同时缩短了定时捕获时间，克服了原来算法中存在的问题。最后，仿真表明该算法的有效性。     

财务报告舞弊行政处罚与可感知审计质量

以2001年至2008年间非金融类、非外资类正常交易A股公司为研究样本,考察财务报告舞弊行政处罚是否传递了可感知审计质量信息,实证研究结果表明：投资者总体上并不认可财务报告舞弊行政处罚传递了可感知审计质量信息,仅当投资者观察到反映坏消息的审计意见（如审计师出具非标审计意见、审计意见未改善等）和反映审计师声誉信息（如审计师受到行政处罚）的情况下,投资者才认为财务报告舞弊行政处罚传递了可感知审计质量信息。     

基于LDA主题模型的专利文本分析应用研究

为了解决运用传统的专利文本分析方法中出现的分类粗糙、科学性不强等问题,提出使用基于Latent Dirichlet Allocation(LDA)主题模型的专利文本分析方法。以我国转基因玉米育种领域专利文本为研究对象,对专利文本主题进行划分。通过实验表明LDA主题模型对专利文本的划分和热门领域的分类准确、有效。并得出结论:对专利文本使用LDA主题模型建模可以实现对专利文本的分类,可以实现对热门领域主题分类、子领域细分,并对未来发展态势给出意见。     

Forecasting the Adoption of GM Oilseed Rape: Evidence from a Discrete Choice Experiment in Germany

This paper explores farmers’ willingness to adopt genetically modified (GM) oilseed rape prior to its commercial release and estimates the ‘demand’ for the new technology. The analysis is based upon choice experiments with 202 German arable farmers. A multinomial probit estimation reveals that GM attributes such as gross margin, expected liability from cross pollination, or flexibility in returning to conventional oilseed rape significantly affect the likelihood of adoption. Neighbouring farmers’ attitudes towards GM cropping and a number of farmer and farm characteristics were also found to be significant determinants of prospective adoption. Demand simulations suggest that adoption rates are very sensitive to the profit difference between GM and non‐GM rape varieties. A monopolistic seed price would substantially reduce demand for the new technology. A monopolistic seed supplier would reap between 45% and 80% of the GM rent, and the deadweight loss of the monopoly would range between 15% and 30% of that rent. The remaining rent for farmers may be too small to outweigh possible producer price discounts resulting from the costs of segregating GM and non‐GM oilseed rape along the supply chain.     

Trends in Approval Times for Genetically Engineered Crops in the United States and the European Union

Genetically engineered (GE) crops are subject to regulatory oversight to ensure their safety for humans and the environment. Their approval in the European Union (EU) starts with an application in a given Member State followed by a scientific risk assessment, and ends with a political decision‐making step (risk management). In the United States (US) approval begins with a scientific (field trial) step and ends with a ‘bureaucratic’ decision‐making step. We investigate trends for the time taken for these steps and the overall time taken for approving GE crops in the US and the EU. Our results show that from 1996–2015 the overall time trend for approval in the EU decreased and then flattened off, with an overall mean completion‐time of 1,763 days. In the US in 1998 there was a break in the trend of the overall approval time. Initially, from 1988 until 1997 the trend decreased with a mean approval time of 1,321 days; from 1998–2015, the trend almost stagnated with a mean approval time of 2,467 days.     

The Costs of Coexistence Measures for Genetically Modified Maize in Germany

We estimate the perceived costs of legal requirements (‘coexistence measures’) for growing genetically modified (GM) Bt maize in Germany using a choice experiment. The costs of the evaluated ex‐ante and ex‐post coexistence measures range from zero to more than €300 per measure and most are greater than the extra revenue the farmers in our survey expect from growing Bt maize or than estimates in the literature. The cost estimates for temporal separation, the highest in our evaluation, imply that the exclusion of this measure in Germany is justified. The costliest measures of the ones that are currently applied in Germany are joint and strict liability for all damages. Our results further show that neighbours do not cause a problem and opportunities for reducing costs through agreements with them exist. Finally, we find that farmers’ attitudes towards GM crops affect the probability of adoption of Bt maize. Our results imply that strict liability will deter the cultivation of Bt maize in Germany unless liability issues can be addressed through other means, for example, through neighbours agreements.     

浅谈改性乳化沥青的道路养护应用

改性乳化沥青在高等级路面已经普遍使用,结合实际介绍了改性乳化沥青及其应用,以及乳化剂、改性剂种类及选择时影响因素。     

The perception of biotechnology in agro-forestry: The opinion of undergraduates and researchers

Genetically modified organisms (GMOs) cropping promoted by different researchers, and the subsequent crisis regarding the safety of food derived from them, has resulted in strong public mistrust towards the authorities, both scientific and political. The aim of this work is to investigate the perception of Italian undergraduates and researchers towards the introduction of GMOs in agro-forestry. The factors determining attitudes towards GMOs were examined by means of 66 questions divided into three units: Knowledge, Opinon, Trust. Anagrafic and socio-cultural information were also analyzed. Data was processed through a multivariate analysis approach. The hierarchical clustering on undergraduates and researchers allowed to distinguish clusters of respondents skilled in biotechnology from those skilled in off-topic disciplines. Principal component analysis and K-means demonstrated that the positive or negative opinion toward GMOs, as for undergraduates, does not depend on their knowledge, but it is associated with the level of trust in the institutions. On the contrary, for researchers, it is related to their expertise level, without any linkage to trust in the institutions. This type of study may represent a key step for understanding the social, economic and scientific components underlying the choices of citizens, communities and society about GMOs.     

Dynamic panel cointegration approaches to the estimation of money demand functions

This paper investigates properties of the money demand functions of Group of Six (G6) member countries (Canada, France, Italy, Japan, U.K., and U.S.) using the estimation and inference techniques of panel cointegration. Empirical analyses are conducted by estimating money demand equations of G6 countries individually and as a whole, allowing heterogeneity in individual specific fixed effects across countries through dynamic, nonstationary panel estimation techniques. By using recently developed panel cointegration techniques, the paper contributes to the literature of money demand studies by improving the power performance of the relevant estimation and inference procedures. It reports fully modified OLS (FMOLS) estimation results of the money demand model for different data frequencies, to find varying signs and magnitudes of real income, interest rates and inflation elasticities of money demand for G6 nations.     

Hypothesis testing and parameter estimation based onM-statistics ink samples with unequal variances

Summary Ink samples with unequal variances,M-tests for homogeneity ofk location parameters are proposed. The asymptoticχ ²-distributions of the test statistics and the robustness of the tests are investigated. NextM-estimators (ME’s) of parameters are discussed. Furthermore positive-part shrinkage versions (PSME’s) of theM-estimators for the location parameters are considered along with modified James-Stein estimation rule. In asymptotic distributional risks based on a special feasible loss, it is shown that the PSME’s dominate the ME’s, and preliminary test and shrinkageM-versions fork≧4.