环洞庭湖特色经济发展能力评价指标体系及评价方法

本文对环洞庭湖特色经济发展能力评价指标体系的必要性及其确立原则进行了剖析，在此基础上试通过对特色产业规模、特色产业投入、特色产业产出效率、特色产业占有市场份额等的评价，设计出具有可操作性的评价指标体系及评价方法，以期对环洞庭湖特色经济发展能力评价有所借鉴。     

最优伍配及其应用

本文给出了图的最优伍配的基本概念并探讨了它的性质、算法及应用。     

蔚县煤田地质构造的演化及特征

燕山西段有许多中生代煤盆地。对这些煤盆地质构造演化和构造特征的研究,不仅可以了解侏罗系煤系地层的发育和分布规律,寻找新的煤田,而且对了解燕山西段地质构造演化和构造特征也具有重要意义。通过对区内构造层的划分和其演化特征的分析,区内地质构造演化可划分为三个阶段:1)太古代地槽发展阶段;2)元古代—古生代为地台盖层发展阶段;3)中生代—新生代为断块构造阶段。为了分析区内构造演化特征,我们还根据矿区内均匀分布的200多个钻孔资料,采用了多项式趋势分析的数学模型,利用计算机进行了趋势分析,拟合出1—4次多项系数。结果证明常规构造分析和数学地质分析完全吻合。矿区内地质构造特征可归为三点:(1)矿区地质构造为一复向斜。该复向斜受太古代古侵蚀面的古地理控制并经过后期构造旋回发育而成。(2)燕山运动把矿区改造成断陷盆地。喜山运动使断陷盆地继续发展。(3)中生代中晚期的辉绿岩侵入和侧向挤压,在矿区内产生一些规模较小的褶皱和断层。同时,我们还讨论了燕山西段侏罗系煤田的空间分布规律,各煤田中聚煤中心和富煤带的分布规律,和各煤田地质构造的后期改造。     

A Note on the Three–Portfolios Matching Problem

A typical problem arising in financial planning for private investors consists in the fact that the initial investor's portfolio, the one determined by the consulting process of the financial institution and the universe of instruments made available to the investor have to be matched/optimised when determining the relevant portfolio choice. We call this problem the three–portfolios matching problem. Clearly, the resulting portfolio selection should be as close as possible to the optimal asset allocation determined by the consulting process of the financial institution. However, the transition from the investor's initial portfolio to the final one is complicated by the presence of transaction costs and some further more specific constraints. Indeed, usually the portfolios under consideration are structured at different aggregation levels, making portfolios comparison and matching more difficult. Further, several investment restrictions have to be satisfied by the final portfolio choice. Finally, the arising portfolio selection process should be sufficiently transparent in order to incorporate the subjective investor's trade–off between the objectives 'optimal portfolio matching' and 'minimal portfolio transition costs'. In this paper, we solve the three–portfolios matching problem analytically for a simplified setting that illustrates the main features of the arising solutions and numerically for the more general situation.     

Scheduling identical jobs on uniform parallel machines

We address the problem of scheduling n identical jobs on m uniform parallel machines to optimize scheduling criteria that are nondecreasing in the job completion times. It is well known that this can be formulated as a linear assignment problem, and subsequently solved in O ( n ³) time. We give a more concise formulation for minsum criteria, and show that general minmax criteria can be minimized in O ( n ²) time. We present faster algorithms, requiring only O ( n + m log m ) time for minimizing makespan and total completion time, O ( n log n ) time for minimizing total weighted completion time, maximum lateness, total tardiness and the weighted number of tardy jobs, and O ( n log² n ) time for maximum weighted tardiness. In the case of release dates, we propose an O ( n log n ) algorithm for minimizing makespan, and an O ( mn ^2m+1) time dynamic programming algorithm for minimizing total completion time.     

Does land registration and certification boost farm productivity? Evidence from Ethiopia

According to economic theory, tenure security is an important determinant of agricultural investment and productivity. Land titling has been at the center stage of development efforts of many African countries to boost tenure security. We investigate the productivity impacts of the Ethiopian land registration and certification program, employing propensity score matching method in an effort to create a credible counterfactual. Consistent with theory, we find land registration and certification has robust positive effects on farm productivity. More tentatively, we identify the assurance effect as one probable channel for impact. Households with land certificates are more likely to adopt soil‐fertility management strategies on their plots than households without certificates.     

基于Landsat-TM和测量地物光谱耦合分析——以开封地区为例

地物光谱数据是遥感技术之基础资料,是建立地面数据和遥感数据关系的桥梁;在对遥感机理和地物光谱理论深入理解的基础上,用回归分析思想探讨遥感影像光谱与实测相应地物光谱的耦合程度,两者的相关系数ρ=0.8689,相关性较好,因此可以将经过大气校正后的影像光谱值代替实测地物的光谱值进行相关的分析。     

基于MAPGIS平台的遥感技术用于土地利用动态监测

主要以SPOT4卫星遥感数据为主要数据源,基于MAPGIS6.5平台对漠河县土地利用动态遥感监测研究项目的运作过程为例进行阐述;首先明确土地利用动态监测的具体内容和技术路线,然后对数据进行预处理,数据的配准和几何校正,图像融合以及信息采集的方法与手段进行了探讨;最后对作业的内、外业主要过程及应提交的成果作了介绍。     

宅基地退出降低了农户的贫困脆弱性吗？ ——来自安徽金寨的证据

研究目的：探究宅基地退出在脆弱性视角下的减贫效应,厘清宅基地退出对农户贫困脆弱性的作用路径。研究方法：基于2019年安徽金寨的微观调研数据,构建广义可行最小二乘法模型,基于期望贫困对农户家庭贫困脆弱性进行测度,采用倾向得分匹配法检验宅基地退出的减贫效应,运用中介效应模型分析宅基地退出影响贫困脆弱性的传导机制。研究结果：（1）在现行贫困标准下,有18.66%的农户面临未来陷入贫困的风险;（2）宅基地退出具有显著减贫效应,能够有效降低农户未来陷入贫困的概率,通过PSM方法消除“自选择”偏误后结果依然稳健;（3）宅基地退出通过增加农户生计资本和改善生计策略来降低贫困脆弱性。研究结论：未来应进一步深化宅基地制度改革,完善宅基地退出与扶贫的联动机制,改进返贫预警的识别机制。     

野外地物光谱测量技术及方法

野外地物光谱测量在航天航空传感器定标、遥感数据解译、遥感应用潜力研究以及地质填图等方面得到广泛应用。野外采集准确的地物波谱需要熟知各种不同的光照条件、大气特性和稳定性(云、风)、仪器视场角、观测和光线照射的结合角度、仪器扫描速度以及目标特征的时空变化等,这些因素对目标波谱具有很大的影响。进行野外光谱测量的第一步是整个试验的总体设计,在设计中必须结合研究目标和研究对象的具体特性综合考虑数据采集的时间、野外测量的空间尺度、光线照射和观测的几何角度以及记录的野外描述数据等问题。此文详细讨论这些因素对地物光谱测量的影响。