Climbing the Electronic Capitol Hill: Personal and Professional Reflections on Teaching about Congress

The Information Revolution, particularly evidenced by the Internet, e-mail and online access to government documents, has significantly affected the way Congress conducts business. The author reflects on the changes that he has had to make during his seven years of teaching a course on Congressional Office Operations for the U.S. Department of Agriculture (USDA) Graduate School. Through personal experiences, interviews, and historical perspectives, he describes changes in information resources, constituent communications, and press operations on Capitol Hill and how these changes have affected course content. He also describes how the events of September 11, 2001, and the anthrax mail problem have forced consideration of an electronic Congress. Serials Review 2002; 28:287–294.     

Abelian and Tauberian Theorems on the Bias of the Hill Estimator

The bias of Hill's estimator for the positive extreme value index of a distribution is investigated in relation to the convergence rate in the regular variation property of the tail function of the common distribution of the sample and the corresponding tail quantile function. Based on the theory of generalized regular variation, natural second-order conditions are proposed which both imply and are implied by convergence of the expectation of Hill's estimator to the extreme value index at certain rates. A comparison with second-order conditions encountered in the literature is made.     

PORT Hill and Moment Estimators for Heavy-Tailed Models

In this article, we use the peaks over random threshold (PORT)-methodology, and consider Hill and moment PORT-classes of extreme value index estimators. These classes of estimators are invariant not only to changes in scale, like the classical Hill and moment estimators, but also to changes in location. They are based on the sample of excesses over a random threshold, the order statistic X _[np]+1:n , 0 ≤ p < 1, being p a tuning parameter, which makes them highly flexible. Under convenient restrictions on the underlying model, these classes of estimators are consistent and asymptotically normal for adequate values of k, the number of top order statistics used in the semi-parametric estimation of the extreme value index γ. In practice, there may however appear a stability around a value distant from the target γ when the minimum is chosen for the random threshold, and attention is drawn for the danger of transforming the original data through the subtraction of the minimum. A new bias-corrected moment estimator is also introduced. The exact performance of the new extreme value index PORT-estimators is compared, through a large-scale Monte-Carlo simulation study, with the original Hill and moment estimators, the bias-corrected moment estimator, and one of the minimum-variance reduced-bias (MVRB) extreme value index estimators recently introduced in the literature. As an empirical example we estimate the tail index associated to a set of real data from the field of finance.     

On multivariate separating Hill estimator under estimated location and scatter

We consider estimating the tail-index of a distribution under the assumption of multivariate ellipticity. Recently, a separating Hill estimator for multivariate elliptical distributions was proposed. This estimator is an affine invariant alternative to using the marginal observations in tail-index estimation and is hence unaffected by, e.g. change of units of measurement. However, the separating Hill estimator depends on the location and scatter of the elliptical distribution, which, in practice, have to be estimated. The effect of replacing the true location and scatter of the distribution by estimates has previously been only examined through simulations. In this article we show that the error caused by replacing the location and scatter of the distribution by estimates indeed is asymptotically negligible. This fact is essential for the practicality of the separating Hill estimator. In addition to providing the theoretical results, we present simulation results on the asymptotic behaviour of the estimators.     

Hill estimator of projections of functional data on principal components

Functional principal component scores are commonly used to reduce mathematically infinitely dimensional functional data to finite dimensional vectors. In certain applications, most notably in finance, these scores exhibit tail behaviour consistent with the assumption of regular variation. Knowledge of the index of the regular variation, α, is needed to apply methods of extreme value theory. The most commonly used method of the estimation of α is the Hill estimator. We derive conditions under which the Hill estimator computed from the sample scores is consistent for the tail index of the unobservable population scores.     

货币电子化的风险及防范

货币电子化是电子商务的核心。电子货币作为当今最新的货币形式 ,既是最时尚的 ,也是最具风险的。文章本着新生事物的产生、变化和发展的哲学理论 ,着重从电子货币自身因素 (特点、功能和种类 )以及电子货币在应运中的若干问题进行风险分析 ,逐而提出科学的防范措施。     

Electronic Social Psychology

Abstract

Unfortunately, it is not possible to comment on how the social psychological community has responded to ESP and its somewhat novel features, because ESP has not yet obtained a large audience. Many social psychologist are interested, but most simply do not have the equipment needed to use ESP. Many have personal computers, but few have modems, and those who do have modes haves not used them much. Further, some have expressed resersvations about the cost of telecommunicating, claiming that traditional means of communication serve the purpose well enough. Cost is a very legitimate concern, as telecommunicating can be expensive, but it is also somewhat short-sighted. (It reminds one of the reaction of some London business men who resisted the telephone because there were plenty of messenger boys in the city.) Computers offer people the chance to communicate and share information in ways that have not been possible before--in ways that can be beneficial to the community of social psychologists. One cannot evaluate telecommunications (or anything) solely in terms of its costs; it should be judged on a cost-benefit bases. While the benefits are somewhat difficult to judge at present, members of the profession will undoubtedly realize them in time. Telecommunications will not only stand the test of cost-benefit evaluation, but pass it with flying colors.     

劳动力成本上升、加工贸易转移与企业出口附加值率攀升

中国出口国内附加值率（DVAR）持续攀升,伴随其上升的是用工成本的明显提高和加工贸易占比的显著下降,中国DVAR的提升究竟源于已有研究所指出的,投资自由化所带来的国内中间品对国外中间品的替代,即“主动”的提升？还是成本上升引致加工贸易不断退出市场的一个客观结果,即“被动”的提升？本文基于2000--2006年的微观数据,测算了企业层面的DVAR,从加工贸易退出的角度刻画了企业DVAR的动态演进过程,并进一步考察了最低工资所代理的劳动力成本、加工贸易与企业出口DVAR之间的关系。实证研究表明：最低工资所代理的劳动力成本上升会促使中国企业DVAR的攀升,这一结果在多个维度的稳健性检验中均是高度稳健的。最低工资上升对中国企业DVAR的促进作用通过引致加工贸易退出这一机制来实现。拓展性的研究还表明,最低工资上升对高生产率企业、外资企业和资本相对密集企业DVAR的正面促进作用更强。我们的发现意味着,中国DVAR的上升至少部分是加工贸易产业转移的结果,鼓励进口,同时促进国内中间品质量提升是我国现阶段发展的重要政策方向。     

电子商务客户网络购物行为挖掘

电子商务已经成为越来越多的消费者购物的一个重要途径，分析网络购物客户的个人特征及其购物行为，对商业的成功有着至关重要的作用。然而电子商务还是一个崭新的商业领域，很多的业界人士仍忙于技术方面的考虑，却很少分析客户的网络购买行为。而使用真实网络购物KDD Cup 2000数据，分析Gazelle．com公司客户的个人特征和网络购物行为，并应用数据挖掘的购物篮模型对各商品之间的关联性进行分析，才能更确切地预测模型预测客户的忠诚度。     

Staffing for Electronic Resource Management

Abstract

The authors offer the results of an informal survey of library staffing trends related to the acquisition and maintenance of electronic resources. They test their hypothesis that the problem of staffing for e-resources has reached a critical level. Serials Review 2002; 28:316–320.     

Negotiating Accessibility for Electronic Resources

Abstract

Accessibility of library electronic resources is a must. Its importance derives from professional ethics of librarianship, rising total costs of acquisition, and mounting legal challenges to colleges and universities that fail to provide resources accessible to users with disabilities. Library staff are responsible for ensuring the accessibility of vendor-licensed eresources. This column reviews the accessibility clauses of nine model license agreements for electronic resources. It describes terms that should go into an optimal accessibility clause and creates a composite model clause. It also provides guidance for library staff seeking to negotiate stronger accessibility language into vendor license agreements. Finally, it addresses the impact of accommodation requests on the total cost of acquiring library eresources, concluding with a call to redouble efforts to advocate for greater accessibility and educate both vendors and library staff about its importance.