基于模糊概率与贝叶斯博弈对信用证 结算风险的研究

信用证结算是我国国际贸易业务中普遍采用的结算方式之一。在国际贸易中,如何更加准确地对信用证结算的风险进行评估和决策,提高企业的风险承载能力,是专家学者们研究并试图解决的问题之一。本文针对国际贸易中进口方可能面对的欺诈风险,立足于不完全信息,将MKV风险测度、国家风险评级、FAHP风险综合评估方法相结合,对信用证风险进行模糊概率综合评估,并在此基础上采用了不完全信息贝叶斯博弈的决策方法,以帮助和指导我国出口企业进行科学决策。     

Productivity and farm size in Australian agriculture: reinvestigating the returns to scale

A positive relationship between farm size and farm productivity is often considered to be largely due to increasing returns to scale in farm production. However, using farm‐level data for the Australian broadacre industry, we found that constant or mildly decreasing returns to scale is the more typical scenario. In this study, the marginal returns to various farm inputs are compared across farms with different sizes. We found that large farms achieved higher productivity by changing production technology rather than increasing scale alone. The results highlight the disparity between ‘returns to scale’ and ‘returns to size’ in the industry, suggesting that productivity improvement among smaller farms can be made through increasing their ability to access advanced technologies, rather than simply expanding their scale.     

Food Demand in Russia: Heterogeneous Consumer Segments over Time

The Russian food system has undergone substantial changes. However, knowledge on how economic transition has affected the structural parameters of food demand is lacking. Based on a two‐stage LES‐LA/AIDS model and annual panel data from the Russia Longitudinal Monitoring Survey (1995–2010), we provide a comprehensive set of food demand elasticities for Russia along two dimensions. First, we estimate demand parameters for three characteristic time periods in order to trace changes during transition. Second, to account for the Russian population's diversity, we derive elasticities for five different consumer segments. These groups are established by a cluster analysis based on households' food purchases. Our findings suggest that demand for food is far from satiated in Russia. We find generally high unconditional expenditure and own‐price elasticities for food. Both expenditure and own‐price elasticities show slight decreases in absolute terms over time. Low expenditure elasticities for staple foods like bread or cereals and high values for luxury goods such as meat, alcohol and tobacco suggest considerable changes in the composition of food baskets with further income growth. Results indicate that food production at home loses in importance while more affluent households in particular increase their demand for food consumption away from home.     

The estimated ex ante economic impact of Bt cowpea in Niger,Benin and Northern Nigeria

Genetically modified (GM) crops could increase economic growth and enhance living standards in Africa, but political issues have slowed the use of biotechnology. This is the first study that assesses the potential impact of GM crops in Africa while considering the preferences of producers and consumers towards GMOs as well as the income and price risks they face. The study uses a choice experiment to estimate the ex ante economic impact of a novel technology, Bacillus thuringiensis (Bt) cowpea, on producers and consumers in Benin, Niger and northern Nigeria. The experiment involves the simulation of a market transaction similar to those in open air markets in West Africa. During the market simulation, respondents are informed about the advantages and disadvantages, including health risks, of Bt cowpea. The results from the study suggest that cowpea growers and consumers in Benin and northern Nigeria prefer Bt to conventional cowpea for health safety reasons. The results estimate that social welfare in Benin, Niger and northern Nigeria would increase by at least US$11.82 per capita annually with Bt cowpea, if seed sectors are operating smoothly. With inefficiencies in seed sectors and the potential for cowpea acreage increase, the estimated social welfare increase in the region would be about US$1.26 per capita annually.     

Food supply chains and sustainability: evidence from specialist food producers in the Scottish/English borders

Despite an increasing interest in more sustainable forms of land management, few analyses have examined whether ‘local’ or ‘alternative’ food supply systems are sustainable in environmental, economic and social terms. Using SUSTAIN's ‘sustainable food’ criteria, this paper analyses the sustainability of a number of ‘speciality’ food supply chains operated by small rural enterprises in the Scottish/English borders. Results indicate that, in the main, the case study businesses are not particularly sustainable; instead, driven by a strong economic imperative, they often have to ‘dip’ into various ‘links’ associated with more conventional (commodity-based) food supply chains. The paper concludes by warning against the tendency to conflate terms such as ‘local’, ‘alternative’, ‘speciality’ and ‘sustainable’.     

基于网络的配电实时监控系统组态软件的研究

随着计算机技术争网络技术的发展,少人职守或无人值班的监控方式大量出现,具有Web服务功能的监控软件成为一种发展趋势。配电网络系统复杂、运行状态变化快速,为了解决网络实时数据传递问题和监控系统对网络数据实时呈现的难点要求,文章提出了基于B/S的实时监控组态软件的系统模型和系统工作原理,建立了基于SVG标准的矢量图形语言的图元模型库,完成了实时监控系统组态软件平台的研究与开发。     

一株恶臭假单胞菌AD-1的好氧反硝化及产酶特性研究

为更好地实现好氧反硝化菌的脱氮性能,本研究基于前期筛选的一株好氧反硝化菌pseudomonas putida AD-1,从脱氮效率及产酶角度考察其不同CODcr/TN和DO下的反硝化脱氮性能。在一定CODcr/TN范围内,CODcr/TN与培养24h后的菌株脱氮效率及ORP的减少量均呈正相关。当CODcr/TN为20.7时,脱氮效率为59.68%;当CODcr/TN为2.1时,脱氮效率仅为7.53%。培养过程中NO2-N浓度虽始终处于较低水平却呈上下波动状态。AD-1菌的ODO在4.82 mg/L左右,与大多数的好氧反硝化菌相比具有更高的氧气忍受浓度。通过SDS-PAGE蛋白电泳可以明显看出不同DO下菌体与反硝化相关的蛋白表达差异性,为进一步研究好氧反硝化菌产酶特性奠定理论基础。     

基于PLC系统的电机故障分析方法探究

《电机安装维护与故障处理》是电气自动化技术专业的必修课,也是维修电工所必需具备的岗位技能,当今的电气自动化技术广泛地使用了PLC/DCS(Programmable Logic Controller可编程逻辑控制器/Distribution Control System集散控制系统)控制系统,利用计算机控制程序对故障的分析具有定位准确、简捷快速的特点,极大地提高了控制质量和运行效率。     

国内外有关电子电器产品能效WTO／TBT通报分析

提高产品能效水平成为全球应对能源危机和达到各国节能减排目标的重要手段。文章从发布数量、成员组成结构和产品类别等方面分析了2007～2010年国内外有关电子电器产品能效的WTO／TBT通报状况,研究此类通报的特点和趋势,为企业应对待机能效壁垒提供技术参考。