消费者交互作用对网络效应产品扩散的影响——基于产品生命周期的视角

从消费者采用产品过程的生命周期(PLC)视角出发,运用微观扩散模型仿真分析消费者交互作用对网络效应产品扩散的影响.研究表明:消费者交互作用所产生的局部网络效应能够加快产品扩散早期和中期速度,而聚集效应则会降低产品扩散中期速度; 消费者之间交互强度越强,产品扩散中期速度越快; 全局交互型消费者则会降低产品扩散早期速度,但能提高产品扩散中期速度;且上述因素对网络效应产品PLC不同阶段扩散速度的影响还会由于消费者交互作用所形成的复杂社会网络结构差异而呈现不同模式.这些研究结论能够为网络外部性市场中企业的营销策略提供一定新启示.     

Modeling the congestion cost and vehicle emission within multimodal traffic network under the condition of equilibrium

Traditional system optimization models for traffic network focus on the treatment of congestion, which usually have an objective of minimizing the total travel time.However,the negative externality of congestion,such as environment pollution,is neglected in most cases.Such models fall short in taking Greenhouse Gas(GHG) emissions and its impact on climate change into consideration.In this paper,a social-cost based system optimization(SO) model is proposed for the multimodal traffic network considering both traffic congestion and corresponding vehicle emission.Firstly,a variation inequality model is developed to formulate the equilibrium problem for such network based on the analysis of travelers’ combined choices.Secondly,the computational models of traffic congestion and vehicle emission of whole multimodal network are proposed based on the equilibrium link-flows and the corresponding travel times.A bi-level programming model,in which the social-cost based SO model is treated as the upper-level problem and the combined equilibrium model is processed as the lower-level problem,is then presented with its solution algorithm.Finally,the proposed models are illustrated through a simple numerical example.The study results confirm and support the idea of giving the priority to the development of urban public transport,which is an effective way to achieve a sustainable urban transportation.     

未知噪声统计的交错估计GPS导航定位算法

将未知噪声统计量的估计与信号状态估计交替进行的算法引入 Ｇ Ｐ Ｓ定位,计算机模拟结果表明效果很好。     

采用分块编码的小波图像压缩技术

研究了基于小波变换的图像压缩技术。在小波分解的基础上,结合人眼视觉系统（ＨＶＳ）特性,提出了一种分块编码的图像编码算法。该算法利用小波变换系数子带内和子带间的相关性以及小波系数的分布特点,有效地对高频子带数据进行了压缩。该方法实现简单,可达到很好的压缩效果。     

基于卡尔曼滤波的二次型神经网络学习算法及收敛性分析

提出了二次型多层前馈神经网络的卡尔曼滤波学习算法,并证明了该算法的收敛性。与文献［２,３］中的学习算法和经典的误差反向传播学习算法相比,新的学习算法具有更快的学习速度、良好的泛化能力,并且对学习率有很好的鲁棒性,不容易陷入局部极小点。仿真实验结果表明了新算法的有效性。     

分布式虚拟环境中虚拟人运动的表示

网络虚拟环境中虚拟人的运动表示与交通工具的运动表示具有完全不同的特点。对此 ,本文提出了一种运动表示法 ,以运动信息的形式表达人体所有关节的变化结果 ,并采用信息包的方式在网上传送 ,可以有效地降低维持虚拟人逼真运动所需要的最小信息传送数量     

基于形状描述直方图的声呐图像目标识别算法

针对水下声呐图像目标检测与识别问题,在图像规格化条件下,定义了几种不同的形状描述子,并统计计算描述子直方图,定义了几种不同的直方图匹配测度函数用以计算直方图间的相似性。分析了算法中关键参数的选取问题。仿真结果表明,基于该算法的识别率可达到98%以上,具有较强的不变性和鲁棒性。通过进一步信息融合算法可快速准确地实现水下声呐图像目标识别,具有较强的应用价值。     

离散事件动态系统理论在通信网络中的应用

通信网络是—个典型的离散事件系统。离散事件动态系统（ＤＥＤＳ）理论综合并提出了许多对离散事件系统建模及性能评估等的方法,为解决通信网络中的一些关键问题提供了有力的工具。本文综述了近年来ＤＥＤＳ理论在通信网络建模、分析、优化以及网络管理等方面的应用进展情况,并提出了一些自己的看法。     

B2B MARKET FORMATION AND WELFARE IMPLICATION IN A BUYER'S MARKET

The emergence of B2B electronic markets has greatly changed the relative bargaining power of buyers and sellers.We study the equilibrium market structure in a buyer＇s market.We find that buyer-controlled B2B markets and neutral B2B markets have different equilibrium structures,and the emergence of B2B markets will increase social welfare,but its effect on buyers and sellers will be different：B2B markets increase the consumer surplus of the end market,but their effects on buyer and seller profits are moderated by the relative bargaining power of buyers and sellers.The profits of the side with much weaker bargaining power will decrease due to the introduction of B2B markets.     

注水系统运行方案优化研究

给出了油田注水系统运行方案的优化方法,建立了以注水系统耗电量最小为目标函数,以井口压力、配注水量、注水站和注水泵排量为约束条件的优化数学模型,提出了两层优化方法,编制的软件对某油田注水系统运行方案进行优化计算,取得了巨大的经济效益.