基于用户集合势估计的认知无线电合作频谱感知

频谱感知技术是认知无线电系统的基本功能,是实现已授权频段的次级动态接入和共享的前提。提出基于用户集合势估计的合作频谱感知方案,旨在通过GEEF（gerschgorin exponentially embedded families）,SPEEF（sam-pled power exponentially embedded families）等算法估计出用户的集合势,即适合参与合作频谱感知的最优用户个数,再从全部合作用户中筛选出相应的频谱观测数据生成全局检测统计量,通过与判决门限进行对比,最终对授权用户状态做出判决。理论分析与实验结果表明,提出的方案能够有效地提高频谱感知的性能。     

The future of small farms in Asia

Farms throughout Asia are predominantly small. By nature, small farms use labour‐intensive production methods. The question arises as to the viability of small farms in the face of the rapidly increasing wage rate in most Asian countries. There is also indication that the production efficiency of small farms has declined relative to large farms in many Asian economies, indicating the increasing disadvantage of small farms in Asia. Therefore, this study argues that unless new policy measures are taken to expand farm size, Asia as a whole is likely to lose comparative advantage in agriculture and become an importer of food grains in the future.     

上海小微企业现状及其扶持政策创新研究

上海小微企业行业多、分布广,在丰富行业门类、链接产业运转、呼应市场供给需求、形成市场合理价格、持续市场竞争活力和推动创业带动就业中功不可没。但受国内外复杂且不确定的经济运行环境的影响,不少小微型企业处于人才缺、融资难、利润薄、发展难的困境之中。优化上海小微企业生存环境,应进一步转变管理理念,完善政策及服务,创新发展模式,引导产业发展,拓展小微企业发展空间,形成支持扶持的合理体制与互动机制,真正发挥小微企业在＂创新驱动、转型发展＂中应有的作用。     

民族关系史中华夏文化的定位

本文对中国民族关系史中华夏文化的定位问题,谈了相关的三个方面内容:(一)从华夏族群认同的产生和依据,可知华夏文化一开始就只把自己定位为中国疆域内各种文化中的一种;(二)汉语文献往往以华夏文化体系为本位来表达和解读他族文化,与其实际可能有一定差异;(三)安史之乱以后,非汉民族群体在中国的主导地位使华夏文化的价值如何体现成为一个难题。     

国外对中小企业的融资支持及其启示

当前制约中小企业发展的因素很多,其中,融资难是主要的"瓶颈"之一。借鉴国外对中小企业发展的融资支持,对于我国尽快健全和完善支持中小企业发展的政策扶持体系,创造良好的金融环境,无疑将积累必要的经验和提供有益的启示。     

城市社区养老服务质量评价--基于粗糙集方法的数据挖掘

客观公正的养老服务质量评价对完善社区养老体系建设有重要意义。本文基于粗糙集的研究方法,分别从生活照料、医疗护理、安全保障、精神慰藉以及社会参与五个维度对显著影响社区养老服务质量评价的指标进行了约简,进而确定质量评价体系的指标和权重,并对吉林市22个社区养老服务的质量进行了评价。结果显示,质量评价平均水平介于“一般”和“比较满意”之间;年龄越高的老年人对社区养老服务质量评价越低;社区养老建设试点小区的评分显著高于非试点小区。由此可见,我国社区养老试点建设已经取得明显成效,但亟须进一步推行和完善。     

The impact of delayed maternity on foetal growth in Spain: An assessment by population attributable fraction

Background

Delayed childbearing is considered a risk factor for maternal–foetal health. As in other higher-income countries, in Spain age at maternity has steadily increased during the last two decades.

On extropy properties of ranked set sampling

Ranked set sampling is a sampling design that allows the experimenter to span the full range values in the population and it can be used widely in industrial, environmental and ecological studies. In this paper, we consider the information content of ranked set sampling in terms of extropy measure. It is shown that the ranked set sampling performs better than its simple random sample counterpart of the same size. Monotone properties and stochastic orders are investigated. Sharp bounds on the extropy of RSS data based on the projection method in the non-parametric set-up as well as Steffensen inequalities in the parametric context are established. The extropy measure can also be used as a discrimination tool between RSS and SRS data.     

Mean-Squared errors of small area estimators under a multivariate linear model for repeated measures data

In this paper, we discuss the derivation of the first and second moments for the proposed small area estimators under a multivariate linear model for repeated measures data. The aim is to use these moments to estimate the mean-squared errors (MSE) for the predicted small area means as a measure of precision. At the first stage, we derive the MSE when the covariance matrices are known. At the second stage, a method based on parametric bootstrap is proposed for bias correction and for prediction error that reflects the uncertainty when the unknown covariance is replaced by its suitable estimator.     

Mean estimate in ranked set sampling using a length-biased concomitant variable

In this paper, a ranked set sampling procedure with ranking based on a length-biased concomitant variable is proposed. The estimate for population mean based on this sample is given. It is proved that the estimate based on ranked set samples is asymptotically more efficient than the estimate based on simple random samples. Simulation studies are conducted to present the properties of the proposed estimate for finite sample size. Moreover, the consequence of ignoring length bias is also addressed by simulation studies and the real data analysis.