延迟容忍网络中一种多信息融合的改进概率路由算法

综合利用节点物理状态信息（位置和速度矢量信息）和社会关系信息（历史相遇信息）,提出一种多信息融合的概率路由算法（PRMF）。该算法依据节点间距离的远近程度动态调整两类信息在预测相遇关系中的权重,以选择合适的信息来计算传输概率,并依据传输概率的大小选择转发节点。另外,还引入有效的分组副本控制和分组散播策略,并结合预测信息改进了节点缓存管理方法。仿真结果表明：与现有的几种路由算法相比,PRMF保持了较低的平均开销,同时具有最高的投递率和最小的平均延迟。     

Yield and income effects of rice varieties with tolerance of multiple abiotic stresses: the case of green super rice (GSR) and flooding in the Philippines

With the increasing frequency of extreme climatic events, the new challenge is to develop rice varieties that are tolerant of drought, water submergence, and salinity. There are now new high‐yielding green super rice (GSR) cultivars developed at the International Rice Research Institute with increased tolerance to multiple abiotic stresses. But a clear understanding of the economic benefits of these varieties under farmers’ production environments is not yet fully understood. In this article, we assess the yield and income effects of GSR rice varieties using a two‐year panel data from one province. We use matched samples from a propensity score matching method and a fixed‐effects model within a difference‐in‐difference (DID) framework to estimate the yield effects. The income effects were evaluated using the parameter estimates from the yield/production function model. The results of the ordinary least squares and DID fixed‐effects regressions reveal significant and positive effects of GSR varieties on yield. The most important finding is that the benefits from these varieties are strongly felt when there is flooding. This evidence was not as robust when matched samples were used. However, it is clear that the yield benefits from GSR varieties could improve rice food security and help alleviate poverty in the country.     

多变量网络控制系统鲁棒容错控制研究

文章研究了一类具有时延和丢包且执行器故障的多变量网络控制系统鲁棒容错控制器设计问题,基于系统中的不确定性,推导了该类网络控制系统的诱导时滞数学模型,并利用李雅普诺夫第二法和自由权矩阵方法,分析了系统的渐近稳定性,得到了系统稳定运行的最大允许时延的条件。最后,通过仿真分析证实了本文所提理论的有效性,以及稳定判据的可行性。     

Adoption of Drought Tolerant Maize Varieties under Rainfall Stress in Malawi

We examine adoption of drought tolerant (DT) maize varieties using a four‐round panel dataset from six districts in Malawi. There is an increase in adoption of DT maize from 3% in 2006 to 43% in 2015 in our data. We focus on the effect of past drought exposure on adoption and the likelihood of DT maize being distributed under the Farm Input Subsidy Programme (FISP). Results show that past exposure to drought increases the probability of DT maize seed being distributed through FISP. Farmers who accessed maize seed subsidy coupons and were previously exposed to late season dry spells are more likely to use the seed subsidy coupon to redeem DT maize seed. The likelihood of adoption and adoption intensity (area under DT maize) are positively influenced by previous early season dry spells and access to seed subsidy. Previous late season droughts also positively affect adoption intensity. On the other hand, area share under DT maize is positively correlated with early season dry spells and past exposure to late season dry spells but negatively related to seed subsidy. FISP in Malawi appears to have stimulated adoption of DT maize directly through subsidy and indirectly through generating farmers’ experiences of the performance of DT varieties under drought conditions.