Re-examining online customer experience to include purchase frequency and perceived risk

This research examines the important emerging area of online customer experience (OCE) using data collected from an online survey of frequent and infrequent online shoppers. The study examines a model of antecedents for cognitive and affective experiential states and their influence on outcomes, such as online shopping satisfaction and repurchase intentions. The model also examines the relationships between perceived risk, trust, satisfaction and repurchase intentions. Theoretically, the study provides a broader understanding of OCE, through insights into two shopper segments identified as being important in e-retailing. For managers, the study highlights areas of OCE and their implications for ongoing management of the online channel.     

高炮随动系统自动测试中正弦机发送频率的确定

在某型高炮随动系统测试中,正弦机的发送频率直接影响着输出信号的平滑度,从而会影响测试的精度。为了避免在正弦机运行过程中,计算耗用过多机时,在正弦机发送之前,先计算出每个位置信号、前馈信号的数值,存放于内存中。本文根据该正弦机信号的特点,分析了几种正弦机角位置信号发送频率方式的优缺点,确定了正弦机发送频率的方式。     

Causality effects in return volatility measures with random times

We provide a structural approach to identify instantaneous causality effects between durations and stock price volatility. So far, in the literature, instantaneous causality effects have either been excluded or cannot be identified separately from Granger type causality effects. By giving explicit moment conditions for observed returns over (random) duration intervals, we are able to identify an instantaneous causality effect. The documented causality effect has significant impact on inference for tick-by-tick data. We find that instantaneous volatility forecasts for, e.g., IBM stock returns must be decreased by as much as 40% when not having seen the next quote change before its (conditionally) median time. Also, instantaneous volatilities are found to be much higher than indicated by standard volatility assessment procedures using tick-by-tick data. For IBM, a naive assessment of spot volatility based on observed returns between quote changes would only account for 60% of the actual volatility. For less liquidly traded stocks at NYSE this effect is even stronger.     

利用矢量网络分析仪测量时延特性的方法

解释了无线射频系统时延指标测量的意义及重要性,介绍了使用矢量网络分析仪进行时延指标测量的基本原理,归纳了网络分析仪进行线性器件、变频器件时延测量的测量方法,重点分析了变频器件时延测量的三种方法的原理、步骤和准确度.     

预应力混凝土梁桥自振特性分析

建立双折线预应力钢筋混凝土等直梁的强迫振动的运动微分方程,分析了梁在预应力钢筋作用下的横向振动问题,将运动微分方程解耦,得到梁在预应力作用下自振频率的解析解,分析了梁的自振频率与预应力和偏心距的关系,通过实例计算,得到了梁在不同预应力时梁桥的自振频率曲线。     

新型波导-微带对脊鳍线过渡设计

介绍了一种新型的宽带波导-微带对脊鳍线过渡设计。它利用对脊鳍线自身结构的调整,就可以对频带内谐振频率产生抑制作用,不需外加任何谐振抑制结构或金属孤岛,减少了设计和制造的复杂性。这种紧凑的过渡模型不仅结构简单、尺寸短小,而且可以在宽频带范围内实现较低的插入损耗和回波损耗,方便工程上的应用。对实验样品的测试表明,在Ka全频段内其插入损耗小于0.8 dB。     

Intraday Lead-Lag Relationships Between the Futures-, Options and Stock Market

In rational, efficiently functioning and complete markets, returnson derivative and underlying securities should be perfectlycontemporaneously correlated. Due to market imperfections, oneof these markets may reflect information faster. The use ofhigh-frequency data and the choice for a small unit time intervalto measure these lead-lag relations comes at the cost of someor many missing observations, causing traditional estimatorsto either under- or overestimate covariances and correlations.We use a new estimator to estimate lead-lag relationships betweenthe cash AEX index, options and futures. We find that futuresreturns lead both options and cash index returns by approximately10 minutes. The relationship between options and the cash marketis not completely unidirectional. JEL Classification: G13, G14     

The Euro Changeover and Numerical Intuition for Prices in the Old and New Currencies

This study examines how numerical intuition for prices in euros and in the Portuguese currency escudos developed in Portugal after the euro changeover. Estimates of prices of 40 different products were collected in the two currencies and at four different times from November 2001 to April 2004. The results regarding price estimates in euros were more in accordance with a relearning hypothesis considering that price estimates become progressively more accurate by a process that is related to purchase frequency. It was also suggested that this is a very slow process and that prices in the former currency are not simply forgotten. On the contrary, the escudos remained a general benchmark for an extended period. The results regarding estimated price intuition and use of intuition in estimating prices are also consistent with a slow adaptation process. Implications for future euro changeovers are discussed.     

TACAN信号处理的MATLAB仿真技术分析

介绍了TACAN系统的信号处理及其计算机仿真.利用MATLAB对TACAN信号的中频数字化及基带信号处理过程进行仿真分析,介绍了同相正交积分数字锁相测方位算法并对其进行了仿真验证.     

基于频率响应屏蔽技术的采样率变换新结构

介绍了频率响应屏蔽(FRM)技术在采样率变换技术中的应用,分析了FRM的简化结构——内插滤波器的设计方法。将此滤波器应用于采样率变换中,并结合多相滤波思想提出了一种高效的FRM采样率变换结构,此结构能极大降低采样率变换实现复杂度。最后通过设计实例,验证了此结构的高效性。