A new approach to the effect of intervention frequency on the foreign exchange market: evidence from Japan

This article estimates and analyses the effect of intervention frequency on the yen/dollar market, using daily intervention data. We examine using a nonlinear methodology, with the frequency of intervention from April 1991 to December 2005 as a focal explanatory variable. In this article, we also introduce a flexible target zone model that is capable of characterizing the dynamic behaviour of an exchange rate implied by the original target zone model of Krugman and its modifications. The empirical results show the importance of considering the threshold effect when analysing the effect of intervention due to the presence of asymmetry in the foreign exchange market. Moreover, we show that a high frequency intervention stabilizes the exchange rate by reducing exchange rate volatility, especially when the yen appreciates.     

Estimation of spot volatility with superposed noisy data

By using high frequency financial data, we nonparametrically estimate the spot volatility at any given time point, while the simultaneous presence of multiple transactions and market microstructure noise in the observation procedure are considered. Our estimator is based on the summation of the locally ranged increments, while kernel smoothing give us spot volatility. Besides, the microstructure noise can be estimated and removed, if it is modeled as bid-ask spread, which is a frequently used assumption. The consistency and asymptotic normality of the estimator are established. We do some simulation studies to assess the finite sample performance of our estimator. The estimator is also applied to some real data sets, further, the relationship between multiple records and spot volatility is also explored.     

射频子宫内膜消融治疗月经过多40例分析

目的：探讨射频子宫内膜消融治疗月经过多的临床疗效。方法：对经射频治疗的40例月经过多患者进行随访及回顾性分析。结果：40例患者中，显效39例(其中闭经32例，月经少于正常量或呈点滴量7例)，有效1例，总有效率为100％，未发生并发症。结论：射频子宫内膜消融治疗月经过多具有操作简单、安全、有效、副作用少、费用低等优点，值得推广。     

基于射频识别的小区门禁系统的开发与设计

小区门禁系统的开发与设计是多门学科的综合,主要是对系统软件的开发,而RFID作为一种无线射频识别技术能够自动识别目标对象,不仅在一卡通方面,而且在物流方面也得到了广泛地应用。在当前信息化时代,社会越来越复杂,各种现象都随时会出现,特别是在住宅小区,由于人多,就会引起一些不当的行为发生,为此小区门禁系统是非常重要的。本文拟将重点分析如何在小区门禁系统的开发与设计中应用射频识别技术。     

快速公交系统发车频率的仿真优化研究

车辆的发车频率是影响快速公交系统运行效率的重要因素。文章以Arena10.0为平台,建立普通车型和长车型的仿真模型,通过系统仿真,优化发车频率。实验表明,长车型和普通车型的最佳发车频率分别为2.6分钟/辆和2分钟/辆。该建模方法和结论对BRT系统运行具有参考意义。     

Organizational Accidents: A Systemic Model of Production versus Protection

Production pressure is often cited as an underlying contributory factor of organizational accidents. The relationship, however, between production and safety protection is complex and has not been adequately addressed by current theories regarding organizational accident. In addressing this gap, this paper uses the methodology of system dynamics to develop a causal model to address the dynamic interaction between management of production and protection, which can accumulate in an organizational accident. A case study of a fatal rock fall accident in Tasmania, Australia was conducted based on the developed model and is used to uncover the intricate dynamics linking production pressure, risk tolerability, perception of safety margin, and protection efforts. In particular, the study demonstrates how a strong production focus can trigger a vicious cycle of deteriorating risk perception and how increased protection effort can, ironically, lead to deterioration of protection.     

土—桩—结构动力相互作用研究综述

近年来,桩基础以其独特的优势在我国城市建设中得到广泛应用文章介绍了土—桩—结构动力相互作用研究的各类方法,并提出了未来发展趋势的展望。     

用HSP50214B实现跳频信号的实时变频解跳处理

本文提出了一种对跳频信号进行解跳的方法。其基本思想是利用数字变频将跳频信号不同频率的各个跳段信号变频到统一载频上,使其转变为定频信号。文中着重论述了变频方案和内部参数的设计,并通过具体的例子说明了本方法基于HSP50214B的实现。     

DDS/PLL在频率合成中的应用

介绍了直接数字频率合成(DDS)技术和模拟锁相(PLL)技术相结合的应用,它是频率合成中一种新的应用,具有体积小、频率稳定可靠、相位噪声低、转换时间快等优良性能。对丰富的杂散进行抑制后,DDS信号在实际应用中可达到理想的效果。     

基于AD6620的中频数字直扩接收机本地载波的同步恢复

直接序列扩频接收机对本地载波的同步要求非常严格, 以往所需电路复杂。本文方法在数字域通过粗、细双环调整达到载波同步,具有同步时间短、精度高、灵活性强、所需器件少、易于实现的优点。本方法已在基于AD6620数字下变频信号处理器的中频数字直扩接收机中得到应用,并可广泛用于数字化扩频电台、遥控遥测等通信系统中。