可列非齐次马氏链的几个极限性质

本文的主要目的是利用田间剖分法研究了可列非齐次马尔可夫链的极限性质,得到了关于ｍ元序组出现频率的几个极限定理,给出了在ａ．ｅ．收敛的意义下非齐次马氏链转移概率的一种频率解释。     

Choices of Varieties and Demand for Improved Rice Seed in Fogera District of Ethiopia

In this study, 151 households were randomly drawn from three randomly selected Kebele in probability proportional to size method. The demographic and socio-economic factors that determine the participation in improved varieties were household labor availability, education level of the household head, land holdings, distance to the nearest village market, proximity to the main market, and distance to access agricultural extension and access to the source of rice seeds. However, determinants of choice decision varied from cultivar to cultivar. The evidence of the study from the interdependence among the decision of adoption of improved rice varieties suggested that technology adoption will be accelerated by launching a progressively developing package and scheme of rice technology generation, and points to the importance of mobilising additional resources to augment households’ efforts at popularization and promotion of improved rice cultivars. The findings from Linearized Almost Ideal Demand Systems (LA/AIDS) model showed that compelling evidence for small proportion changes in own prices and cross price of improved rice varieties led to greater than unitary proportionate changes in their purchases. The results generally showed that farmers were very sensitive to changes in improved rice seed prices and incomes. The major implication of the findings was that any intervention to improve farmers’ seed purchases should take into account efforts to increase farmers’ purchasing power of agricultural inputs like improved seeds and fertilizers.     

食品消费的几乎理想需求系统分析

利用几乎理想系统（AIDS）对河南城镇居民的食品消费状况进行了系统分析，建立了几乎理想需求系统模型，并在此基础上进行了需求支出弹性和需求价格弹性（自价格弹性和交叉价格弹性）分析，结果表明，在5大类食品消费中，粮食和肉禽蛋是城镇居民的主要消费品，约占食品消费的55%，烟酒茶消费份额随着人们收入提高呈下降趋势，各种食品跳出“短缺”困境，食品间的替代关系增加。     

一类强大数定律的推广（Ⅱ）

设｛Ｘｎ，ｎ≥１｝是概率空间（Ω，Ｆ，Ｐ）上的任意一个随机变量序列，（Ａｎ，Ｆｎ－１）ｎ≥１是一可料序列，本文给出了Ａｎ－１［Ｘｕ－Ｅ（Ｘｎ｜Ｆｎ－１］几乎处处收敛的充分条件，所得结果是一类强大数定律的推广。     

中国木材进口需求材种结构数量关系分析

文中采用近乎理想的需求系统模型,分析中国木材进口需求的结构性特征及各材种之间的经济学关系。研究发现:进口针叶材的支出弹性明显高于阔叶材,说明进口木材消费规模的扩大将在更大程度上带动针叶材需求;针叶锯材进口需求富有弹性而其他商品进口需求缺乏弹性,尤其是阔叶原木进口需求曲线最为陡峭;不同材种之间的交叉价格弹性为负值,同一材种之间的交叉价格弹性为正值,说明不同材种之间为互补品,而同一材种之间为替代品;粗加工产品进口价格的上涨会引发深加工产品进口量的上升,如果再加上旺盛的进口需求,这一效果将更为明显。     

随机序列最大值与最小值联合之几乎处处收敛

证明了独立同分布随机序列最大值与最小值联合分布的几乎处处中心极限定理     

随机变量序列最大值的局部几乎处处中心极限定理

在一定条件下得到了最大值的局部几乎处处中心极限定理.     

一类三阶半线性方程的概周期解

本文借助于积分算子L_(α,β,γ),在Banach空间中,依Schauder不动点定理,证明一类三阶半线性方程以(ω_1,ω_2)为指数基的Fourier概周期解的存在性和唯一性,并给出概周期解的表达式。