一种级联两箱通用数字预失真器及其辨识算法

提出了一种由单形规范线性分段(SCPWL)函数与记忆多项式级联的数字预失真器，并给出了复数域两步最小二乘参数辨识算法。不同于以往一种预失真器适用一种功放模型的情况，所提的预失真算法利用SCPWL函数的分段特性以及记忆多项式的非线性记忆特性，在完成参数辨识的同时自动地调整结构，可适用于传统以及强非线性新型功放模型的线性化补偿。将所提预失真器分别应用于传统记忆多项式、两箱模型以及新型包络跟踪功放。经过计算机仿真，功放输出的幅频特性和频谱曲线表明所提预失真器能够有效地补偿多种功放的非线性特性。算法仿真比较结果也表明，针对包络跟踪功放，所提复数两步最小二乘算法的邻道泄漏比(ACLR)可改善约35 dB，性能优于最小均方(LMS)类算法约30 dB。     

Volatility forecasting: long memory,regime switching and heteroscedasticity

In this article, we account for the first time for long memory, regime switching and the conditional time-varying volatility of volatility (heteroscedasticity) to model and forecast market volatility using the heterogeneous autoregressive model of realized volatility (HAR-RV) and its extensions. We present several interesting and notable findings. First, existing models exhibit significant nonlinearity and clustering, which provide empirical evidence on the benefit of introducing regime switching and heteroscedasticity. Second, out-of-sample results indicate that combining regime switching and heteroscedasticity can substantially improve predictive power from a statistical viewpoint. More specifically, our proposed models generally exhibit higher forecasting accuracy. Third, these results are widely consistent across a variety of robustness tests such as different forecasting windows, forecasting models, realized measures, and stock markets. Consequently, this study sheds new light on forecasting future volatility.     

半导体存储器及发展趋势

半导体存储器的容量和速度决策着计算机系统运行速度。目前CPU芯片18个月一更新，为了赶上这个速度，半导体存储器的发展也日新月异。     

Measuring Hospital Performance in the Presence of Quasi-Fixed Inputs: An Analysis of Québec Hospitals

This research proposes an approach to measure hospital performance based on a generalization of Banker and Morey (1986) and Førsund (1996). This approach considers quasi-fixed inputs explicitly, calculates their implicit cost, and quantifies returns to scale. The performance measure is decomposed into allocative and technical inefficiencies. Based on a very complete data set of Québec hospitals, we find that significant inefficiencies of up to 17% ($700 CAN million) could have been saved through improved performance. Postestimation analyses that include qualitative measures of care suggest that differences in performance are attributable to differences in management or unobservable quality of care rather than patient case mix.     

Memory recall errors in retrospective surveys: A reverse record check study

This paper reports on a study to compare self-reports during an interview with staff who attended a University health centre in Turkey, with the records of visits to the same health centre over the previous 12 months. Design of the study reflects the effects of importance of the event, duration since the event, frequency of the occurrence of the event, measurement scale of the event, and bounded and unbounded recalling. In order to assess the extent of recall error, responses to retrospective questions on health centre visits are compared with administrative records. Statistical models are proposed for short and long term human memory recall error effects on responses.     

互联网行为管理系统(BCS)中精简TCP/IP的实现

文章介绍了对防火墙通用TCP/IP实现的修改,经修改过的TCP/IP实现将在代码量、协议的完备性、内存的开销、总体性能方面得到提高。     

Testing of unit roots and other fractionally integrated hypotheses in the presence of structural breaks

Tests of unit roots and other nonstationary hypotheses that were proposed by Robinson (1994) are applied in this article to the Nelson and Plosser's (1982) series. The tests can be expressed in a way allowing for structural breaks under both the null and the alternative hypotheses. When applying the tests to the same dataset as in Perron (1989), we observe that our results might be consistent with those in Perron (1989) when testing the nulls of trend-stationarity or a unit-root. However, we also observe that fractionally integrated hypotheses may be plausible alternatives in the context of structural breaks at a known period of time. Final version received: August 2000/Final version accepted: August 2001 RID="*" ID="*"  The author gratefully acknowledges the financial support from the European TMR grant No. ERBFMRX-CT-98-0213. Comments of two anonymous referees are also acknowledged.     

Long memory in volatilities of German stock returns

We show that there is strong evidence of long-range dependence in the volatilities of several German stock returns. This will be done by applying a method using the difference of the classical log-periodogram regression estimator for the memory parameter and of the tapered periodogram based estimator. Both estimators give similar values for the memory parameter for each series and this indicates long memory. To support our findings we apply also a methodology using the sample variance and a wavelet based estimator to the data. Also these two methods show clear evidence of long-range dependence in the volatilities of German stock returns.First version received: December 2001/Final version received: March 2003The computational assistance of Eleni Mitropoulou and Björn Stollenwerck as well as the helpful comments of two unknown referees are gratefully acknowledged. Research supported by Deutsche Forschungsgemeinschaft under SFB 475. Stock returns were obtained from Deutsche Finanzdatenbank (DFDB), Karlsruhe.     

控制权收益作为国有控股公司高管激励的影响因素研究

本文将控制权收益分解为隐性收益和显性收益。结果表明，显性收益占控制权收益的9％左右，隐性收益仍是我国上市公司高管的首要激励因素。研究还显示，隐性收益和控制权收益与企业规模和经营绩效呈显著的负相关，与第一大股东控股比例呈显著的正相关。而显性收益与企业规模和经营绩效呈显著的正相关，与第一大股东控股比例呈显著的负相关；隐性收益还与公司资产负债率呈显著的负相关。最后，提出将自我隐形激励转变成市场显性激励的政策建议。     

“景观记忆”在城市文化景观设计中的 应用

以文化遗产景观“记忆”为线索，探讨文化遗产景 观保护的设计应用与方法。提出阐述了文化景观“记忆三元 素”及其在文化遗产景观感受中的关键作用：1)人类活动的 文化历史记忆；2)自然生态的环境变迁记忆；3)景观营造的 文化景观实体空间风貌记忆。基于现代景观的开放性和参与 性，以2个文化景观遗产设计实践为案例，从人的景观感受 出发，分析探讨了文化遗产景观感受与记忆的因果关系，阐 述了“记忆三元素”作为人、场所和城市之间互动的一种联 系，而成为三者交流的共同“语言”，及其三元耦合、主客 互动关系。基本结论：“记忆”是一种物质文化资源和社会 文化实体，在一定程度上可以展现历史、现实和未来脉络； “记忆”强化了人与场所之间的互动、场所与城市之间的联 系以及人类文明历史的延续；基于记忆的城市文化遗产景观 设计行之有效