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。     

Does studying abroad enhance employability?

Over 200,000 European students study abroad under the Erasmus programme. It appears that studying abroad may impart skills which are helpful for professional careers after graduation. Approximately, 54% of European students report that participation in the Erasmus exchange programme helped them to obtain a first job; however, interestingly, those from Central and Eastern European countries report it much more often—in 73% of cases. The aim of this paper is to find out whether studying abroad enhances the employability of higher education graduates in Poland. Using the propensity score matching method and data from a nationwide tracer survey of Polish graduates, we find that Polish students who completed at least one semester of their studies abroad do not benefit in terms of a higher employment rate after graduation.     

INTERNATIONAL RESERVE MANAGEMENT: A DRIFT‐SWITCHING REFLECTED JUMP‐DIFFUSION MODEL

We study the cost of shocks, that is, jump risk, with respect to reserve management when the reserve process is formulated as a drift‐switching jump diffusion with a reflecting barrier at 0. Inspired by the Brownian drift switching model, our model results in a more realistic dynamic behavior of international reserves than the buffer stock model. The new model can capture both the jump behavior in reserve dynamics and the leptokurtic feature of the increment distribution which has a higher peak and two asymmetric heavier tails than the normal distribution. Through the selection of an initial distribution that reflects certain steady state behaviors, the reserve process becomes a regenerative process. This selection enables us to derive a closed‐form expression for the total expected discounted cost of managing reserves, thus helping us to numerically find management strategies that minimize costs. The numerical results show that shocks at the reserve level have a significant effect on reserve management strategies and that model misspecification can result in nonnegligible additional costs.     

基于高校教师职业特点的激励机制探析

在对高校教师激励机制现状分析之后,针对高校教师的职业特点,提出了高校教师激励机制模式:薪酬激励、社会保障计划、参与激励、竞争激励、组织文化激励、工作激励。     

论青少年犯罪动向及对策

近几年,青少年犯罪案件呈突发性、偶发性,犯罪年龄降低,由单独型向团伙型发展的特点.其原因有家庭因素、学校因素、社会因素.预防和惩治青少年犯罪,需要全社会广泛参与,综合治理.     

邓小平发展观的基本特征

邓小平发展观是邓小平理论的核心内容之一.邓小平发展现,体现了视野的全球性、内涵的丰富性、体系的创新性、思维的辩证性、取向的人民性等基本特征.邓小平发展观是与时代和国情相适应的社会主义发展观,是科学发展观确立的思想基础.     

蜜月游市场特征的相关与回归分析——针对北京常住居民蜜月游市场

在我国,蜜月游市场发展迅猛,潜力巨大,收益率颇高.特别值得注意的是,我们调研发现:高收入者与非高收入者共享蜜月游这一高端旅游产品.为此我们进行了相关的定量分析,以进一步研究其发展脉络,揭示其变动趋势,为政府主管部门及相关旅游企业提供决策依据.     

广东省现代物流的供需匹配研究

广东省现代物流正处于快速增长的阶段，如何协调物流供给与需求的矛盾，是现代物流发展过程中不可避免的问题。本文从物流的需求和供给的状况着手，分析了广东省现代物流存在供需不平衡问题的原因与表象，对匹配广东省现代物流的需求与供给提出了几条建议。     

我国疫苗供应链浅析

在分析疫苗物流特性的基础上,总结了我国疫苗供应链存在的问题,指出其主要原因是:利益分配不合理、供应层次过多、供应垄断、监管机制不合理,并提出了增加财政投入、分离运营与监管、改变调整供应链结构、加强信息化监管等措施。