基于IP分布式MSC的CDMA2000系统A接口设计与实现

针对传统集中式移动交换中心(MSC)容量小、安全性低、不易扩展的不足,基于IP技术和软交换技术,提出了一种分布式MSC架构.在此架构下对A接口协议进行了分析并给出了基于IP的实现方案:兼顾TCP的可靠性和UDP的简洁性定义了承载A接口中的信令和业务的一个增强性UDP协议(EUDP).此外,也描述了分布式MSC负荷分担的选择原则:轮选、处理最近和资源最近;最后以8 kbit/s语音业务为例,对基于IP传输语音业务的带宽需求进行了简单分析.实践表明,该方案不仅提高了系统的经济性,也改善了网络容量扩展和新业务提供的灵活性.     

Modeling Methods for Discrete Choice Analysis

This paper introduces new forms, sampling and estimation approaches fordiscrete choice models. The new models include behavioral specifications oflatent class choice models, multinomial probit, hybrid logit, andnon-parametric methods. Recent contributions also include new specializedchoice based sample designs that permit greater efficiency in datacollection. Finally, the paper describes recent developments in the use ofsimulation methods for model estimation. These developments are designed toallow the applications of discrete choice models to a wider variety ofdiscrete choice problems.     

Estimating Discrete Joint Probability Distributions for Demographic Characteristics at the Store Level Given Store Level Marginal Distributions and a City-Wide Joint Distribution

This paper provides a solution to the problem of estimating a joint distribution using the associated marginal distributions and a related joint distribution. The particular application we have in mind is estimating joint distributions of demographic characteristics corresponding to market areas for individual retail stores. Marginal distributions are generally available at the census tract level, but joint distributions are only available for Metropolitan Statistical Areas which are generally much larger than the market for a single retail store. Joint distributions over demographics are an important input into mixed logit demand models for aggregate data. Market shares that vary systematically with demographics are essential for relieving the restrictions imposed by the Independence from Irrelevant Alternative property of the logit model.We approach this problem by formulating a parametric function that incorporates both the city-wide joint distributional information and marginal information specific to the retail stores market area. To estimate the function, we form moment conditions equating the moments of the parametric function to observed data, and we input these into a GMM objective. In one of our illustrations we use four marginal demographic distributions from each of eight stores in Dominicks Finer Foods data archive to estimate a four dimensional joint distribution for each store. Our results show that our GMM approach produces estimated joint distributions that differ substantially from the product of marginal distributions and emit marginals that closely match the observed marginal distributions. Mixed logit demand estimates are also presented which show the estimates to be sensitive to the formulation of the demographics distribution.The views expressed are not purported to reflect those of the United States Department of Justice     

基于Truetime工具箱的网络控制系统的仿真研究

网络控制系统(NCS)是目前网络和通信领域的研究热点,由于网络的引入,网络控制系统的仿真研究存在一定的难度。本文首先给出了NCS的定义,介绍了网络控制系统的研究现状,以及现有的网络控制系统的仿真软件,并重点介绍了Truetime工具箱。应用MATLAB和Truetime工具箱为基础,以一个三回路的网络控制系统为实例建立了Truetime仿真模型,通过仿真数据分析,验证了基于Truetime工具箱的网络控制系统模型的有效性。网络控制系统的推行,能够有效地减少人工错误,为用户节省大量时间。     

珠三角潮感区排涝泵站规模选取

随着珠三角地区经济的高速发展,涝区越来越淹不得,迫切需要提高排涝标准,而设置排涝泵站是主要措施之一。在实践中,业界主要通过平均排除法、洪峰流量法以及河道调蓄法来确定泵站规模。笔者通过对里水涝区的分析研究,初步提出考虑闸站联排模式的计算方法,继而结合雨峰与洪峰遭遇分析最终确定以河道调蓄方法计算珠三角潮感区排涝泵站的规模,通过实践验证,这种方法是合理可行的。     

高职“虚实互补”实训体系研究——以应用电子技术专业为例

高职的培养目标定位在高素质的技术技能型人才,在培养中要实现实践应用能力和理论分析能力并重。本文介绍了一种将虚拟仿真技术融入到应用电子技术专业实训体系,构建了虚实互补的实训体系,以期实现高职理实并重的培养目的,改善目前只强调实践动手能力而忽略理论分析能力而引起的高职学生后劲发展不足的问题。     

Experiential Learning – A Case Study of the Use of Computerised Stock Market Trading Simulation in Finance Education

Abstract

Finance is a popular programme of study in UK higher education despite it being a challenging subject that requires students to understand and apply complex and abstract mathematical models and academic theories. Educational simulation is an active learning method found to be useful in enhancing students’ learning experience, but there has been limited pedagogic research attention on its use in finance education within the UK. This paper, utilising an on-line survey, provides a snapshot of the current usage of finance-related simulations across the 97 UK universities offering finance programmes. The paper also reports the findings of a case study that offers insights into the effectiveness of introducing computerised simulation into a postgraduate finance course from both a student and tutor perspective. It highlights an enhancing learning experience for students through concrete experience and reflective observation, increasing their understanding of difficult and complex finance concepts.     

民间资本投资黑龙江省银行业的有效模式及对策研究

近十年来,民间资本在黑龙江省各领域的利用情况日趋增多,发展潜力大。金融市场的投资环境改善,使得黑龙江省对民间资本的需求日益扩大。黑龙江省银行业可通过参股、合资、独资新设和兼并收购四种可行性模式吸收民间资本,黑龙江银行业应健全相关法律法规,加大财政扶持倾斜力度,使民间资本合法有序、稳健顺畅地进入银行业;建立风险防控和组织管理机制、完善信用评估体系,使民间资本安全可控、益于公众;创新银行业务服务,优化金融文化环境,为民间资本开辟新天地,并使其获得长效发展,从而强化黑龙江省银行业融资结构,促进全省经济增长。     

Exploring longitudinal risk‐return relationships

We study a longitudinal fit model of adaptation and its association with the longitudinal risk‐return relationship. The model allows the firm to adjust its position in response to partial learning about a changing environment characterized by two path‐dependent processes—a random walk and a stochastic trend. Computational simulations at low levels of learning in both environmental contexts are consistent with empirical data. However, the results are also consistent when firm behavior appears to be mindless in the form of a random walk. Hence, both imperfect learning and a mindless random walk can lead to the inverse longitudinal risk‐return relationships observed empirically. We discuss this apparent paradox and the possible resolution between mindless and conscious behavior as plausible causes of the longitudinal Bowman Paradox. Copyright © 2014 John Wiley & Sons, Ltd.     

港口物流系统的调度仿真研究

港口调度是港口生产组织的关键问题,调度方案的好坏直接决定了港口作业的效率,本文首先对集装箱港口物流系统的结构、控制需求等进行了分析,然后提出了应用AutoModV10.0仿真软件,构建具有离散性、随机性特征的港口物流系统模型的方法。