信息非对称程度与企业家效用、资本结构、企业市场价值

本文分析了市场信息非对称程度对企业家投资效用、企业债务水平及企业市场价值的影响。分析表明,若企业项目是高质量的,信息非对称程度的降低可使企业项目市场价值和债务水平提高;反之,若企业项目是低质量的,信息非对称程度的降低可使企业项目市场价值和债务水平减少;外部知情投资者比例的变化与企业家效用的变化之间的关系与企业质量有关。     

Weighted adaptive multivariate CUSUM charts with variable sampling intervals

The adaptive multivariate CUSUM (AMCUSUM) chart has received considerable attention because of its superior sensitivity against a range of mean shift sizes than that of the conventional non-adaptive multivariate CUSUM (MCUSUM) chart. Recently, weighted AMCUSUM (WAMCUSUM) charts with a fixed sampling interval (FSI) have been proposed, called the WAMCUSUM-FSI charts, which provide more sensitivity than the AMCUSUM-FSI charts. In this paper, we extend this work and propose WAMCUSUM charts with variable sampling interval (VSI), named the WAMCUSUM-VSI charts, for efficiently monitoring the mean of a multivariate normally distributed process. The Monte Carlo simulation method is used to compute the average time to signal (ATS) and the adjusted ATS (AATS) profiles of the existing and proposed charts. It is found that the WAMCUSUM-VSI charts perform substantially and nearly uniformly better than the WAMCUSUM-FSI charts in terms of the ATS and AATS performance criterion. An example is given to explain the implementation of the WAMCUSUM charts with fixed and VSIs.     

Maximum entropy extreme‐value seasonal adjustment

Some economic series in small economies exhibit meagre (i.e. non‐positive) values, as well as seasonal extremes. For example, agricultural variables in countries with a distinct growing season may exhibit both of these features. Multiplicative seasonal adjustment typically utilises a logarithmic transformation, but the meagre values make this impossible, while the extremes engender huge distortions that render seasonal adjustments unacceptable. To account for these features, we propose a new method of extreme‐value adjustment based on the maximum entropy principle, which results in replacement of the meagre values and extremes by optimal projections that utilise information from the available time series dynamics. This facilitates multiplicative seasonal adjustment. The method is illustrated in the New Zealand agricultural series.     

基于压缩感知的自适应加权匹配追踪算法

压缩感知（compressed sensing,CS）技术通过减少发射导频数来提高频谱的利用率。将CS技术应用于导频辅助的稀疏度未知的正交频分复用（orthogonal frequency division multiplexing,OFDM）信道估计中,提出一种自适应加权匹配追踪（CS-based adaptive weighting ＆matching pursuit,AWMP）算法。该算法使用自适应加权、匹配追踪的方法估计信道时域脉冲响应,按照估计信噪比和匹配原则,利用多次迭代进行自适应加权和寻找最佳稀疏度,实现未知信道稀疏度与信噪比的情况下,准确估计信道信息。仿真验证表明,与传统的信道估计算法相比,采用基于AWMP的信道估计方法,能够利用较少的导频信息获得更低的误码率和均方误差。     

Adaptive c-chart with estimated parameter

In the design of control charts, it is usually assumed that process parameters are known. However, in many practical applications the values of these parameters are unknown and should be estimated using historical in-control process observations. In this study, the performance of adaptive c-chart with estimated parameter is evaluated. It is demonstrated that by increasing the size and the number of samples in estimating the process parameter, the performance of the chart converges to that of the known parameter case. Finally the best phase I sampling scenarios are presented to make the chart with the estimated parameter perform as well as the chart with the known parameter.     

交叉口公交优先技术现状与问题

城市公共交通优先通行是提高公交车准时率的关键性措施,交叉口公交优先通行能够减少公交车辆在交叉口的延误,通过设置公交专用进口道以及交叉口公交信号优先控制,从而提高城市公交的服务水平。分析国内外交叉口公交优先研究现状,指出目前交叉口公交优先通行技术研究中存在的主要问题和不足,并提出相关对策和建议。     

引号--"三新”的形式标志

时下"三新”词语(即"新显修辞”、"新显词义”、"新显词语”)大量涌现,在口语中,人们往往会用重(zhong)读的方式来提示强化;在书面上,则往往会采用在新词语上加引号的形式来提示强化.引号的功能之一是成为"三新”词语的标志,当"三新”词语渐变为人所熟知,成为固定静态词语之后,也就不再需要引号这一形式标志了.     

金融风险预警:评价指标、预警机制与实证研究

世界各国经验表明,金融风险预警势在必行且切实可行.文章在梳理金融风险预警相关研究成果基础上,首先提出一套具有强警戒功能的金融风险评价指标体系,在各项指标预警界限基础上将金融风险预警分等定级,分别为I级(安全)、II级(基本安全)、III级(警惕)、Ⅳ级(危险);然后建立基于BP人工神经网络模型的金融风险预警模型,并对1993-2007年我国金融风险情况在MATLAB软件中进行模型的训练、检验和预测,得出我国2008年预警结果:国家综合金融风险:Ⅳ级,危险状态;财政贸易风险:III级,警惕状态,有风险;宏观经济风险:III级,警惕状态,有风险;银行风险:Ⅳ级,危险状态;其他风险(主要指股市风险):III级,警惕状态,有风险.因子分析结果表明:(1)从静态看,我国国债规模2008年仍在适度区间内,暂时没有大的风险.但从动态趋势看,我国正面临巨大的债务压力和与日俱增的潜在风险,国债规模处于国民经济应债能力宽松而财政债务(含隐性债务及或有债务)负担沉重的矛盾之中,应未雨绸缪,努力预防财政风险.(2)2008年上半年宏观经济风险下降到较为合适的范围,实际情况完全符合预测值.2008年下半年,全球金融危机的影响引发宏观经济风险上升.从总体看,2008年国民经济保持一定增长,但速度低于前几年,2009年我国宏观经济风险更大,不容乐观.(3)国有企业的过度负债、亏损经营和庞大的不良资产,以及近几年银行通过大量增加向房地产、钢铁、水泥、汽车等行业贷款和个人消费贷款而引起的投资过热、信贷增长率过高,必须警惕不良资产的再生.(4)股市泡沫风险等其他风险是近两年我国证券市场过度膨胀引起的过热反应,2008年股市的实际运行结果表明预测结果是可信的,预计2009年股市泡沫风险与2008年持平.     

基于ARM和DSP的多轴伺服系统以太网通信

在包含多路伺服驱动的系统中,保证各伺服传动协同运行是一个重要课题。文章研究了由ARM为上位机、多路伺服传动DSP控制核心为下位机的一个专用系统的通信问题,利用以太网UDP组播通讯技术组网,实现了上位机操控整个伺服系统实现多轴伺服同步运行的通信目的。     

《现代数字信号处理》的教学研究与实践

分析了控制学科与工程学科开设《现代数字信号处理》课程存在的主要问题,在教学内容、教学方法、辅助教学和教学管理的四个层面详细阐述了解决这些问题需要遵循的原则和应采取的具体措施,文章针对该课程教学提出的教学方法和实践内容,能够为相关学科的教学工作提供有益的借鉴或参考。