Some results about averaging in stochastic approximation

The paper presents some results concerning the averaging approach in a general linear regression model in one dimension under suitable conditions about the martingale structure of errors. At first asymptotics of the primary and averaged estimators are discussed. Then it is shown that variances of estimators can be consistently estimated by appropriate integrated squared deviations functionals. Finally applications to the construction of confidence regions are considered.     

细微处见态度——谈高校来华留学生管理工作

随着对外开放的逐步深入,外事作为窗口部门的重要性愈加明显。高校接收来华留学生的规模逐年扩大,管理工作的制度化、规范化将有利于外事工作的持续健康发展并直接提升我们的国际形象。     

一种基于Excel的跨系统数据整合分析方法——以某三甲医院零星维修成本核算为例

针对当前信息化智能化过程中,单位各部门自建系统相互孤立、数据标准不一致,难以互联互通,而在管理实践中往往需要在多个系统数据整合分析,而这样的需求常常难以得到信息部门及时反馈,立项难、开发慢.针对这样的问题,本文以某三甲医院零星维修成本核算为例,介绍了一套基于Excel的,适合非信息专业人员获取数据,清洗数据,整合数据,...     

Research collaboration model in academic social networks

ABSTRACT

This paper proposes a hybrid collaboration recommendation method that accounts for research similarities and the previous research cooperation network. Research cooperation is measured by combining the collaboration time and the number of co-authors who already collaborated with at least one scientist. Research similarity is based on authors’ previous publications and academic events they attended. A weighted directed graph is built to discover new collaborators by using direct and indirect connections between scientists. Moreover, a consensus-based system is built to integrate bibliography data from different sources. The experimental results show that our method improves the recommendation performances over other methods.     

A DC programming heuristic applied to the logistics network design problem

This paper proposes a new heuristic method for the logistics network design and planning problem based on linear relaxation and DC (difference of convex functions) programming. We consider a multi-period, multi-echelon, multi-commodity and multi-product problem defined as a large scale mixed integer linear programming (MILP) model. The method is experimented on data sets of various size. The numerical results validate the efficiency of the heuristic for instances with up to several dozens facilities, 18 products and 270 retailers.     

The spillover effects of infill developments on local housing prices

This paper examines the spillover effects of infill developments, which involve developing vacant or under-used parcels within existing urban areas that are largely developed, on local housing prices. Employing a difference-in-difference specification on a sample of 275 new developments and 55,887 sale transactions of houses in Singapore, we find that infill developments have a positive and persistent impact on local housing prices. The contagion effect is larger for infill developments that are built on teardown sites. The spillover effect can also be traced to the overpricing of new homes by developers. Overall, the evidence indicates that developers act as price leaders and contribute significantly to price discovery in the local housing market.     

我国县域经济可持续发展问题与对策探析

县域经济已经成为我国国民经济的重要组成部分。目前我国县域经济存在发展不平衡、产业层次和劳动力素质低下、自然资源浪费、生态环境恶化、产业要素缺乏、国家投入不合理等问题。我们应该制定县域经济的发展规划,加强对县域经济的分类指导;积极推进农业产业化,切实提高农民收入;提高劳动力素质;节约使用自然资源,保护生态环境;积极推进城镇化,促进城乡协调发展。     

食品中单核细胞增生李斯特氏菌改良增菌液的研究

本文通过改变丙酮酸钠以及酵母浸膏添加量,对李氏增菌肉汤(LB₁)进行了改良。通过吸光度法以及平板计数法测定不同优化条件下单核细胞增生李斯特氏菌生长曲线,并采用实时荧光PCR对增菌结果进行特异性验证。得到改良后的增菌液配方为:在商品化李氏增菌肉汤(LB₁)的基础上,添加1 g·L^-1的丙酮酸钠,15 g·L^-1的酵母浸膏,此时前增菌时间可缩短至8 h,且经过验证,特异性良好。使用改良后的李氏增菌肉汤(LB₁)大大缩短了增菌时间,特异性良好,值得推广和应用。     

Can farmers extend their cultivation areas in urban agriculture? A contribution from agronomic analysis of market gardening systems around Mahajanga (Madagascar)

The rapid urbanization in developing countries implies an increasing pressure on urban agriculture for production. As most perishable food products come from this agriculture in close proximity to population concentrations, we analysed from an agronomic point of view how market-garden farmers can meet this increasing urban demand. This work took place in the case of Mahajanga, a secondary city with high increasing demographic rate on the Northwest coast of Madagascar. Based on preliminary surveys to characterize the farming systems (on a sample of 91 farms), 11 market-garden farmers chosen in the three main agricultural zones of the urban area were surveyed during two years. Surveys aimed at understanding their decision rules in crop choices, crop allocation to land and resource management, and to estimate their room for manoeuvre to increase their leafy vegetable areas under cultivation. The wholesalers and retailers who buy the farmers’ produce were also surveyed. A previous model of decision rules regarding crop location on farm territory was used to analyse the on-farm surveys and cartographic methods (GIS and on-farm manual representations) were used to quantify the land use. We highlight the following major points. (1) The leafy vegetable production in the surveyed farms already intensively uses land: farmers have complex decision rules largely depending on the water dynamics in the two main environments (lowlands and lakesides) where leafy vegetables are cultivated during the dry season. (2) The scarcity of farmers’ resources (labour money and water) leads to very little internal room for manoeuvre to increase the leafy vegetable production in the farms. (3) At territorial level however, some land reserve exist in one of the lowlands, but not on lakesides. The water availability for agriculture must be better informed through specialized hydrologic studies, as one of the main constraints nowadays to extend the agricultural area. An extrapolation to other cases of urban agriculture is then discussed as well as the role of agronomy to help urban planners to consider the place of agriculture in the urban development.     

Cultural distance and cross-border bank linkages

This study investigates the effect of cultural distance on global bank linkages using country-pair data for the period 1990–2013. We followed Schwartz (2006) to measure cultural distance, and employed the number of bank pairs involved in cross-border syndicated lending from the source to target countries as a measure of bank linkages. We found that cultural distance has a negative association with bank linkages. This effect is stronger in countries featuring higher informational asymmetries, as represented by weaker institutions, higher uncertainty, or revolution shocks. Our results hold even when employing alternative measures of bank linkages and cultural distance, and when considering the potential endogeneity of cultural distance.