混合拉曼/EDFA放大器及其在DWDM中的应用

本文综述了混合拉曼／掺饵光纤放大器（HFA）的工作原理，结构和特点，介绍了4类HFA基本结构及其实验结果，并通过介绍近年来各类HFA在密集波分复用（DWDM）系统中的应用表明了HFA在带宽，增益和噪声特性方面的优点。     

Markets and pro-poor agricultural growth: insights from livelihood and informal rural economy models in Malawi

This article presents the development of a set of programming models describing the major features of different rural livelihoods and of the informal rural economy they together make up in Malawi. The models allow for differentiated responses by different household types to change and for the partial equilibrium effects of consequent supply, demand, and price adjustments in labor and grain markets. The models provide insights into the relations between own‐farm and nonown‐farm activities in different households' livelihoods and in the informal rural economy as a whole, and are used to investigate possible impacts of increasing cash crop prices and of a more open rural economy. Impacts of these changes on the poor are found to be critically dependent upon supply and demand elasticities in labor and grain markets, but the poor could potentially suffer significant losses from increased openness of the local economy leading to increased expenditure by less poor households on imported goods and services.     

Factors that affect accountant's perceptions of alternative work arrangements

Advances in technology have impacted accounting careers with resulting changes in where, when and how accountants perform their job duties. In addition, employee attitudes towards, and need for, better work/life balance has led to more firms offering alternate work arrangements (AWA). Research suggests that AWA programs can lead to many benefits for both employers and employees. Despite the prevalence of these programs there are relatively few accountants working under these arrangements and concerns about work/life balance continue. This study examines factors that shape perceptions of the cost and benefits associated with the adoption and/or support of AWAs across work culture, gender and participation experience. Our results suggest that work environment had a significant effect on perceptions of AWAs. Public accountants perceived greater costs related to career advancement but correspondingly less concern about administrative issues than management accountants. We also found that accountants who have participated (or are currently participating in an AWA), perceived greater benefits and less concern for potential negative consequences to their careers than non-participants. Finally, women perceived greater benefits to result from participation in an AWA and men perceived correspondingly more costs. Regardless, both genders perceived that AWAs were not strictly a women's issue. These findings contribute to our understanding of alternate work arrangements and point to factors that must be addressed to increase the acceptance and success of these programs.     

高速移动数据传输新标准IEEE 802.20

介绍了未来高速移动通信新标准IEEE802．20的总体概况，具体分析了IEEE802．20的技术特性、系统参考结构以及系统的组成模型，并对IEEE802．20标准前景分析与展望进行了详细描述。     

The European high-speed train network: Predicted effects on accessibility patterns

The principal aim of this paper is to evaluate the impact of the future European high-speed train network on accessibility, by reducing time distance between places and modifying their relative location. We compare the current situation with that foreseen for the year 2010, according to the Outline Plan of the European High-Speed Train Network, in order to analyse which areas will most benefit from construction and improvement of the infrastructure. It is hypothesized that the high-speed train will certainly bring the peripheral regions closer to the central ones, but will also increase imbalances between the main cities and their hinterlands. A weighted average distance indicator is applied for this purpose. This measure identifies the spatial distribution of accessibility in the area of study, emphasizing the infrastructure effects, and locates accessibility changes at the European level. A Geographic Information System (GIS) has been used to carry out this study.     

基于DSRC和CDPD的先进公交系统

本文首先讲述了ITS中的2种通信技术——专用短程通信（DSRC）和蜂窝数字分组数据网（CDPD）的基本概念、工作原理及系统特点等，然后提出了一种基本这2种通信技术的先进公交系统，并对各个子系统的功能结构进行了描述。     

美国空军卫星控制网的现状与发展趋势

近几年的几场局部战争部分表明了现代军事航天系统的重要性。本文主要介绍了美国最重要的一个军事航天测控网－－空军卫星控制网的情况，希望能对了解美国军事航天测控体制有所帮助。     

科技英语中数量增减的译法

本文系统地归纳了在科技文献中常见的涉及到倍数增减的结构及其表达方式     

A Pricing and Hedging Comparison of Parametric and Nonparametric Approaches for American Index Options

This article investigates the extent to which options on theAustralian Stock Price Index can be explained by parametricand nonparametric option pricing techniques. In particular,comparisons are made of out-of-sample option pricing performanceand hedging performance. The dataset differs from many of thoseused previously in the empirical options pricing literaturein that it consists of American options. In addition, a broaderspectrum of techniques are considered: a spline-based nonparametrictechnique is considered in addition to the standard kernel techniques,while the performance of a Heston stochastic volatility modelis also considered. Although some evidence is found of superiorperformance by nonparametric techniques for in-sample pricing,the parametric methods exhibit a markedly better ability toexplain future prices and show superior hedging performance.     

Optimality conditions¶and bubbles in sequential economies¶and bounded relative risk-aversion

We provide specific qualifications in order that Kuhn–Tucker type Euler equations and transversality conditions at infinity hold in stochastic equilibrium models with heterogeneous agents and where assets are traded in sequential markets. It is not assumed that uncertainty is modeled as an event-tree structure or that preferences are necessarily bounded. We also describe an important class of preferences based on bounded relative risk aversion which yields relevant simplifications. Our results are used to establish conditions that rule out asset pricing bubbles. Specific examples of economies with bubbles are also discussed. Received: 28 January 2002 / Accepted: 19 July 2002 We are grateful to the editor and an anonymous referee for their valuable comments. This research was partially supported by MURST (Italy), National Group on “Nonlinear Dynamics and Stochastic Models in Economics and Finance”.