探析气象网络新闻特点及写作技巧

继报刊、广播、电视之后,网络媒体凭借其多媒体、互动性、易于检索、海量信息、迅速传播等特性,已迅速成为新的主流媒体。传播介质的不同使网络新闻的采写有着与传统新闻相比更为特殊的要求,而气象网络新闻的自身的独特性又决定了其新闻采写方式的不同。认真研究气象网络新闻采写的特殊性,掌握气象网络新闻采写的特点、特殊技巧及方法,对于提高气象网络新闻传播的质量,增加气象网络新闻传播的影响力具有重要意义。     

高等学校程序设计类课程教学方法改革与实践

针对程序设计类课程教学中存在的问题及原因进行了研究和分析,针对实际情况提出了教学改革看法,并分别实现了网络教学、成立项目小组和实践教学等教学改革。通过改革实践,提高了学生的自主学习能力和解决问题能力,取得了良好的教学效果。     

基于BP神经网络的粮食产量预测模型

提高我国粮食产量的预测精度与效率是人们关注的一个重要问题.BP模型是目前最为广泛应用的神经网络模型之一,它是一种简单又非常有效的算法.将BP神经网络模型应用到粮食产量预测中,并建立了粮食产量的神经网络预测模型,结果表明BP神经网络应用于粮食产量预测是可行的.     

基于无线传感器网络的农田信息采集系统的研究

针对农田种植区域广、数据采集量大、信息实时传输难的特点,设计了基于无线传感器网络的农田信息采集系统,构建了一个切实可行的农田信息无线传感网络系统,解决了节点定位、路由协议应用等问题.该系统能够在实际生产过程中减少人力操作和人工测量的误差,降低农业生产的成本,并可以最大程度地实现农田信息自动精确的实时采集、汇聚和传输,农...     

Glass transition behavior of corn distillers dried grains with solubles (DDGS)

Distillers dried grains with solubles (DDGS), a major co-product from the corn ethanol industry, has high feed value for its chemical composition. The ratio of wet distillers grains (WDG) and condensed distillers solubles (CDS) added during the production process determines the chemical composition of DDGS. Effect of changing this ratio and the influence of moisture content on glass transition behavior of DDGS was studied. Five prediction models were evaluated to explain the glass transition of DDGS. The mixed trends in the result indicated the complex behavior of DDGS particles and revealed that both moisture content and chemical composition impact the glass transition behavior of DDGS. Onset glass transition temperature ranged from 20 to 30 °C depending on the chemical composition. Kwei equation predictions were better than the predictions by Gordon-Taylor equation. The glass transition temperature of DDGS can be mathematically explained by combining the moisture content and chemical components protein, fiber, glycerol, and sugar percent. The artificial neural network (ANN) model gave a better prediction of onset and midpoint glass transition temperature of DDGS and this might be due to the accurate mapping of the interaction between chemical components.     

Artificial neural network analysis of lipase-catalyzed synthesis of sugar alcohol ester

Artificial neural network (ANN) analysis of immobilized Candida antarctica lipase B-catalyzed esterification of palmitic acid with xylitol was carried out. Temperature, time, amount of enzyme, amount of molecular sieve, substrate molar ratio and volume of solvent were the six important parameters used as the inputs of the network trained by Levenberg-Marquardt (LM) algorithm. After evaluating different ANN configurations, the best network was found to be consisted of two hidden layers with six and seven neurons in the first and second layers respectively, using a hyperbolic tangent sigmoid transfer function. The coefficient of determination (R²) and mean square error (MSE) values between the actual and predicted responses were 1 and 1.5025e−24 for the training and 0.97239 and 0.03259 for the testing datasets. The results indicate the good generalization performance of the neural network model and its capability to predict the conversion of the substrates.     

基于BP滤波的Fourier模型在粮食产量预测中的应用

本文尝试将经济学中的功率谱分析（BP滤波）与统计学中的Fourier模型相结合,先利用BP滤波选出对气候产量波动影响较大的周期,再对这些周期建立Fourier模型来拟合气候产量;同时运用多项式模型拟合趋势产量,并用滞后模型对残差进行修正,以提高粮食单产预测的精确度。利用1961-2000年粮食单产序列数据,分别采用Fourier方法和多项式滞后方法、BPNN法和灰色模型法建立模型,以2001-2012年粮食单产数据进行拟合检验。将这3种方法拟合结果进行比较。结果表明,本文引入的模型通过0.01水平的显著性检验且相对误差均在5%以下,利用模型对粮食单产进行中长期预测的结果表明,2013-2017年中国粮食单产将稳定在6018.6～6466.7kg·hm?2。BP神经网络法模拟的粮食单产虽然拟合相对误差较小,但模型不能得到直观解释,在预测时存在一定的随机性;灰色模型模拟的粮食单产相对误差高达35%,与实际产量存在较大差异。研究结果反映出Fourier模型和多项式滞后模型在粮食产量预测中,其精确度更高且更直观,能够用以预测未来粮食单产以及未来气候变化对粮食单产的影响。     

Distribution of trust model in P2P network based on equilibrium theory

There are a large number of malicious attack nodes and collusion groups in P2P(peer to peer) network, and the existing trust models improve the P2P network environment to some extent, but the emphasis of the models are different, which are unable to fully solve large-scale malicious attacks and deception. Therefore, a P2P trust model based on equilibrium theory is presented. The model consists of the construction of the trust structure, the malicious node detection and trust speculation. It constructs trust network according to the equilibrium theory, uses the equilibrium theory to define nodes balance factor, detects balance malicious nodes by calculating the impact of malicious behavior on the network, and adopts trust inference algorithm to estimate trust nodes to prevent distrust network nodes being added. Experimental results show that the model is reliable, and the algorithm is efficient and robust.     

无线传感器网络在农业中的应用进展

结合无线传感器网络在农业应用中的实际需要,对无线传感器网络技术在温室、灌溉、禽畜养殖和病虫害防治中的研究现状作了简要综述,指出现今无线传感器网络技术中亟需解决的问题,并对其未来的发展趋势作了展望。     

新产品开发角度试析数字图书馆VPN专网绩效评估

通过对黑龙江地市图书馆VPN专网使用绩效评估,对照新产品开发角度4大类14个指标评分,探讨VPN专网是否适合数字图书馆使用。