高分1号冬小麦解译面积核算方法研究

[目的]以高分1号(GF-1)融合2m卫星遥感影像为基础数据源,结合土地利用现状数据、高分多源遥感影像和地面样方等数据,对冬小麦分类提取中存在的面积误差问题进行研究和分析。[方法]文章以河南省永城市为研究区,在冬小麦提取结果聚类处理基础上,基于线性地物缓冲区数据,采用GIS空间运算实现线性地物面积扣除,接着分析了样方数据和土地利用现状数据再扣除零星地物面积比例上的差异,并采用样方零星地物平均扣除系数对全市各乡镇耕地与非耕地中冬小麦提取面积进行了相关统计和误差分析。[结果]永城市冬小麦最终解译面积11. 29万hm~2,其中线性地物和零星地物扣除面积分别为6 613. 08hm~2和3 875. 22hm~2,占研究区冬小麦解译面积的5. 86%和3. 32%,与统计上报数据相比,其处理前后误差由14. 12%降低至4. 41%,有效地提高冬小麦提取面积精度。[结论]误差来源分析与修正对冬小麦解译面积核算精度具有重要影响,该研究为县级区域尺度下冬小麦面积提取核算提供了思路和借鉴。     

Large scale infrastructure investment and economic performance – a case study of Oresund

We analyse the effect of a large scale infrastructure investment, namely the construction of the Oresund bridge, on the local and supra-regional economy. We employ the synthetic control method to construct counterfactual regions that mimic the trajectory of Malmo and Southern Sweden without treatment. Our results point to a positive effect. However, placebo tests in space and time only reveal statistical significance at a larger regional level. The results suggest that spillover effects are eminent.     

科技对纺织的战略意义

世界主要工业发达国家以及亚洲“四小龙”在工业化过程中，尤其是在工业化初期和中期，作为劳动密集型的纺织工业具有重要的推动和关联作用。从目前和今后一段时期我国经济发展和工业化趋势来看，纺织工业在21世纪前50年间，在出口创汇、增加就业、扩大消费等方面仍将为我国国民经济发展起到重要的支撑作用，这种作用是其他产业一时难以取代的。这与中国纺织工业在原料供给、加工能力、产业体系、劳动力成本及素质等方面仍然具有明显的比较优势，以及占有世界市场最多的份额作为竞争的基础有着直接关系。由此，依靠科技、深化改革把我们的纺织大国建成纺织强国越来越具有重要的战略意义。     

略论中国企业跨文化管理的原则与方法

本文阐述了跨文化管理的基本原则,重点探讨了企业实施跨文化管理的主要方法。     

浅析物流产业的发展途径

探讨了物流在经济生活中的作用和现阶段我国物流产业方面存在的问题。提出了发展我国物流产业的基本途径。指出了我国的物流企业应该适时调整经营战略。顺应世界经济的发展趋势。不断提高自身的生存和发展能力。以应对未来更为激烈的竞争局面。     

货币政策的目标、效能与协调运用

货币政策的目标是多元化的，如价格稳定、经济增长等。通过货币政策的调整可以发挥其调节经济的效能。在货币政策协调过程中，运用好与其它社会经济政策的关系，对于提高宏观调控的科学性大有裨益。     

What Role Taxes and Regulation? A Second Look at Open Market Share Buyback Activity in the UK

This paper re-examines the evidence on open market share repurchase activity reported by Rau and Vermaelen (2002) for the UK. Using data from the Securities Data Corporation (SDC), Rau and Vermaelen conclude that the level of repurchase activity is trivial. They attribute the low repurchase volume to regulatory restrictions that limit companies' ability to take advantage of an undervalued stock price and conclude that the bulk of repurchase activity that does occur is driven by the desire to generate tax credits for pension funds. Using data collected from a variety of sources, we find that the SDC substantially understates UK open market buyback activity. Based on our more comprehensive dataset we conclude that (a) pension funds' tax considerations are not the primary cause of UK share repurchases and (b) despite the prevailing regulatory environment, underpricing still represents an important determinant of repurchase activity.     

How to measure mutual fund performance: economic versus statistical relevance

In the present paper a comprehensive assessment of existing mutual fund performance models is presented. Using a survivor‐bias free database of all US mutual funds, we explore the added value of introducing extra variables such as size, book‐to‐market, momentum and a bond index. In addition to that we evaluate the use of introducing time‐variation in betas and alpha. The search for the most suitable model to measure mutual fund performance will be addressed along two lines. First, we are interested in the statistical significance of adding more factors to the single factor model. Second, we focus on the economic importance of more elaborate model specifications. The added value of the present study lies both in the step‐wise process of identifying relevant factors, and the use of a rich US mutual fund database that was recently released by the Center for Research in Security Prices.     

A conceptual framework of anonymity in Group Support Systems

As the development and use of automated systems for collaborative work grows, the need for a better understanding of these systems becomes more important. Our focus is on one type of system, a Group Support System (GSS) and, in particular, on one important aspect of a GSS—anonymity. A conceptual framework for the study of anonymity in a GSS is presented, which describes the general classes of variables and their relationships. These variables include the factors that influence anonymity in a GSS, types of anonymity, and the effects of anonymity on a message sender, receiver, group process, and outcome. Each of these variables is discussed with working propositions presented for important group process and outcome measures. The objectives of this article are to highlight the importance and complexity of anonymity, to act as a guide for empirical investigations of anonymity, and to influence future GSS development and use.