IPv4与IPv6协议的比较

互联网已经成为现代社会信息基础设施的重要组成部分,在国民经济发展和社会进步中起着举足轻重的作用,同时也成为当今高科技发展的重要支撑环境,互联网的巨大成功有目共睹。现在被全球广泛使用的互联网协议IPv4是"互联网协议第四版",在过去的应用具有辉煌的业绩,但是现在已经露出很多弊端。IPv6协议是"互联网协议第六版"的缩写。在设计IPv6时对原IPv4协议各方面都进行了重新考虑,做了大量改进。文中将先简单的介绍IPv4和IPv6,然后分析IPv4和IPv6协议的区别。     

SAVING IS NEVER A CONSTRAINT ON INVESTMENT1

Saving is regarded in mainstream macroeconomics as a volitional relationship, like consumption. This paper argues that this view is incorrect. There is no independent volitional saving function. Since all goods produced are either consumption goods or investment goods, saving, defined as “income not consumed”, is the accounting record of investment spending. Changes in the definition of investment produce identical changes in saving, with no accompanying volitional change in saving behavior. “Saving” in economics should properly be termed “abstention” since it does not constitute transitive behavior. To understand saving behavior a Hicksian definition of income must be used, and capital gains and losses must be included in the definition of income. In modern capitalist economies most saving undertaken by agents is non‐volitional, and takes the form of permitting the market value of total net wealth to increase.     

美海军C4I系统配置管理研究

介绍了美海军C4I系统配置管理的主要机构和程序,分析了其主要特点.在此基础上,得出了互连互通互操作对我们的一些启示.     

An event study of institutions and currency crises

We use event study methodology to examine the behavior of seven institutional variables eighteen months prior to and after a currency crisis. Our data on institutions include bureaucratic quality, corruption, ethnic tensions, external conflict, internal conflict, government stability, and law and order over the period 1984-2002. Our country coverage includes forty industrial, emerging market, and developing economies for various regions of the world. The graphical event study shows that there are many instances where institutions are weaker in periods before and after a currency crisis than during tranquil periods. The evidence is most compelling for government stability, law and order, bureaucratic quality, and corruption. We also test for differences in the mean values of institutional variables in turbulent periods around a crisis event and tranquil, non-crisis periods. Results from our tests generally complement evidence from the event study.     

Canadian takeover announcements and the job security of top managers

This study measures the turnover rate of top managers (Chief Executive Officers or Presidents) in acquisition targets following the public announcements of takeovers in Canada. Turnover rates following the announcements of completed and unsuccessful takeover attempts did not differ from each other but were higher than the norm for CEOs from a control group of nontarget firms. The turnover rate was particularly high for widely‐held firms and negatively correlated with the preannouncement performance of the targets. Overall, results suggest that a major objective of takeovers in Canada is to reduce management failings, inefficiency, and agency costs. Copyright © 2007 ASAC. Published by John Wiley & Sons, Ltd.     

移动IPv6在无线局域网中的实现

介绍了移动IPv6的工作机制,提出一个移动IPv6和无线局域网(WLAN)集成的设计方案,以实现移动终端在无线局域网之间无缝切换,并建立实际的实验环境对移动IPv6进行测试.     

Unawareness and bankruptcy: A general equilibrium model

Summary. We present a consistent pure-exchange general equilibrium model where agents may not be able to foresee all possible future contingencies. In this context, even with nominal assets and complete asset markets, an equilibrium may not exist without appropriate assumptions. Specific examples are provided. An existence result is proved under the main assumption that there are sufficiently many states that all the agents foresee. An intrinsic feature of the model is bankruptcy, which agents may involuntarily experience in the unforeseen states. Received: April 23, 1997; revised version: May 19, 1997     

Modelling Population and Resource Scarcity in Fourteenth‐century England

This paper examines the empirical data relevant in the analysis of the agrarian transformation of England in the Middle Ages. It presents an empirical analysis of available data that investigates the role and extent of resource scarcity in 14th‐century England. The analysis offers a way forward for economists and historians to reach a plausible consensus about the reality of what may be one of the most important transition periods in European economic history. The insights gained throw useful light on the processes whereby agricultural relations evolved from ancient feudal structures.     

网络化制造的资源运营模式研究

企业生产所需资源有4个要素:物料、信息、资金和知识(即MICK).建立在供应网络基础上的网络化制造模式为MICK资源集成运作提供了条件.企业要获取核心竞争力,就要快速集成MICK资源.文章指出,企业可以在供应网络的基础上,利用自身核心资源撬动MICK等资源,达到资源运作效果.     

浅析第二代互联网对教育信息化的影响

基于IPv6技术的第二代互联网正在渐渐的融入到教育应用当中,为教育信息化注入新的血液。本文介绍了第二代互联网的特点,并浅析了以IPv6为核心技术的第二代互联网对教育信息化的影响。