宁夏专业技术人才的系统分析及需求预测

系统分析了1980年以来宁夏专业技术人才在总量、结构、分布、效益等方面的变化状况，通过回归分析建立了宁夏专业技术人才总量与国内生产总值、从业人员总数的计量模型，模型的拟合优度达到了92．5％，通过了显著性检验．在此基础上，根据宁夏国民经济和社会发展未来目标，预测了2010-2020年宁夏专业技术人才需求总量及效益，对于制订未来宁夏专业技术人才的发展规划具有指导意义．     

Bowman库存策略下的供应链稳定性及需求放大分析

为了研究不同库存策略对供应链稳定性的影响,基于一般线性需求预测,在考虑在途库存的Bowman库存补给策略和不考虑在途库存的(R,S)库存补给策略2种情况下,研究了供应链的稳定性,并在考虑在途库存的Bowman库存补给策略下对需求放大进行了度量和分析.结果表明:在考虑在途库存的Bowman库存补给策略下,当订单平滑参数满足0<γ≤1时供应链稳定;不考虑在途库存的(R,S)库存补给策略,当提前期由小于2变到等于2再变到大于2时,供应链从稳定变到边际稳定再变到不稳定;考虑在途库存的Bowman库存策略中,不同的参数对需求放大程度会产生不同的影响,合理选择参数可以减小需求放大程度.     

集成学习算法的比较研究

从差异性出发,研究了基于特征技术与数据技术的集成学习算法,深入分析了这些集成学习算法产生差异性的方法;针对决策树与神经网络模型在标准数据集对集成学习算法进行了实验研究,结果表明集成学习算法的性能依赖于数据集的特性以及产生差异性的方法等因素,并且基于数据的集成学习算法的性能优于基于特征集的集成学习算法的性能.     

古菌病毒

古菌病毒的研究起步较晚,但发展很快。近年来,人们已经从热泉等特殊环境分离得到了数十种古菌病毒。来自热泉的古菌病毒表现出了极为独特、多样的形态学和基因组学特征,据此目前已经或正在建议建立7个病毒新科。已知的古菌病毒均属于双链DNA病毒,极端嗜热古菌病毒中绝大多数基因的功能尚不清楚。古菌病毒的研究不仅极大地丰富了人们对自然界病毒多样性的认识,还为探索病毒的起源与进化提供了重要启示。本文对古菌病毒的主要类群及特点作了简单介绍,并进一步探讨了病毒的起源与进化。     

对“翻译职位热”的思考

翻译是一种特殊形式的信息传播,在国际交往中的作用显而易见。以企业为主体、市场为导向、产学研相结合的技术创新体系的建立,促进了企业融入国际市场竞争,参与国际市场经济发展。我国加入WTO之后,采取有效政策措施,吸引更多的跨国公司在我国设立研发机构,同时,又鼓励更多有实力的中国企业实施"走出去的战略",到海外设立研发机构,这增加了对翻译人员的需求。翻译人员要提高自身素质,适应时代发展的需要。     

Relationship between plant species diversity and patch characteristics in a marsh in the Sangjiang Plain,China—Using Yaluhe farm as an example

Based on Quick Bird satellite image data, the present study examined small-scale herbaceous community patches in the marsh of the Sanjiang Plain and measured patch characteristics such as the area, perimeter and shape by GPS. The coenological characteristics of the patches were investigated using quadrat method, and the vascular plant species were recorded using transect method. A total of 219 plant species were recorded, which represents 12.2% of the vascular flora in Heilongjiang Province. Our results showed that species number S correlated with patch area and perimeter; richness index (R) correlated with patch perimeter; Simpson index (D) correlated with patch area and perimeter/area; Shannon-Wiener index (H′) correlated with patch area, perimeter and perimeter/area; Evenness index (Jsw) correlated with perimeter/area. Both S and R have significant difference between different size of patches. Plant diversity in the small-scale herbaceous communities tended to increase with the patch area and perimeter. We concluded that edge effects and the habitat heterogeneity of the patches are important in determining the number of species. The relative smoothness of the patch edges also affects the plant diversity of the patches. The richness of plant species in the marsh in the Sanjiang Plain is highly sensitive to the small-scale patches, which continues to play an important role in preserving plant diversity in the local area.     

Modeling an Elastic-Demand Bimodal Transport Network with Park-and-Ride Trips

This paper presents a network equilibrium formulation for modeling commuters＇ travel choices in a bimodal transport system with park-and-ride （P＆R） trips while the total demand is elastic to the congestion level of the network. A super-network approach is adopted in the proposed model. It is assumed that commuters＇ trips are categorized into two types, auto mode only and a combined mode with both auto and transit modes. The former is referred to as the pure mode trip and the latter as the P＆R mode trip. The proposed model simultaneously considers the commuter＇s choice of the pure mode versus the P＆R mode, the choice of parking location for the pure mode, the choice of transfer point for the P＆R mode, as well as the route choice for each mode. The demand elasticity of transport system, the capacity constraints of transport facilities, and the congestion interaction throughout the super-network are also explicitly incorporated into the proposed model. The results of the numerical experiment show the following key findings： （i） traditional parking/P＆R models may overestimate or underestimate travel demand distribution over network; （ii） parking/P＆R, transit scheduling, and carpooling schemes bring significant impacts on commuters＇ travel behavior and network performance; and （iii） different transport policies may be to some extent mutually substituted .     

需求价格弹性应用中的一个约束条件

需求价格弹性在经济理论的定理分析中具有广泛的应用性。商品价格的变化对总收益的影响取决于该商品需求价格弹性的大小，即对需求富有弹性的商品涨价会减少总收益，降价会增加总收益；而对需求缺乏弹性的商品，涨价会增加总收益，降价会减少总收益。但需求价格弹性与总收益的这种关系有一定条件约束，不满足这个约束条件，需求价格弹性与总收益之间就不具有如上关系。文中主要给出这个约束条件。     

二十一世纪中国高校图书馆范型转变

从社会化角度探讨图书馆范型的转变及信息服务手段的多元化，做到“以读者为本、以服务为本、重视服务承诺”，使高校图书馆实实在在地成为“大学的心脏”，在信息社会的竞争中立于不败之地．     

STBC-OFDM发送分集技术

基于正交设计的空时分组编码技术，在瑞利衰落信道中用多个发送天线，其正交结构及最大似然解码算法降低了接收机的复杂度，提高了分集增益，改善了系统性能。讨论了STBC－OFDM发送分集的技术和性能。