基于智能Agent技术的个性化数字图书馆系统模型

根据智能Agent的特性将其应用于智能信息检索,并应用于图书管理系统。针对个性化数字图书馆的具体需求,对原图书馆系统进行了功能扩充。     

Optimal designs for exponential regression

This paper is concerned with the optimal design problem for the particular case of non-linear parametrisation:the parameters to be estimated are included in exponents.Some properties of locally optimal designs as functions of estimated parameters are investigated and a table of such designs in given.We consider also designs to be optimal in the sense of minimax approach.     

Controlled Direct and Mediated Effects: Definition,Identification and Bounds

Abstract. Results are given which provide bounds for controlled direct effects when nounmeasured confounding assumptions required for the identification of these effects do not hold. Previous results concerning bounds for controlled direct effects rely on monotonicity relationships between the treatment, mediator and the outcome themselves; the results presented in this article instead assume that monotonicity relationships hold between the unmeasured confounding variable or variables and the treatment, mediator and outcome. Whereas prior results give bounds that contain the null hypothesis of no direct effect, the results presented here will in many instances yield bounds that do not contain the null hypothesis of no direct effect. For contexts in which a set of variables intercepts all paths between a treatment and an outcome, it is possible to provide a definition for a controlled mediated effect. We discuss the identification of these controlled mediated effects; the bounds for controlled direct effects are applicable also to controlled mediated effects. An example is given to illustrate how the results in the article can be used to draw inferences about direct and mediated effects in the presence of unmeasured confounding variables.     

On Calculations Involving the Maximum Cell Frequency

We describe a method of computing the cumulative distribution function of the maximum and minimum cell frequencies in sampling distributions commonly encountered in the analysis of categorical data.The procedure is efficient for exact or approximate calculation in both homogeneous and non-homogeneous cases, is non-recursive, and does not require Dirichlet integrals.Some related statistical problems are also discussed.     

Practices and Flows of Digital Photography: An Ethnographic Framework

This article develops a methodological framework for undertaking empirical studies of practices and flows, of doings and circulations, of digital tourist photography. The article outlines what might be termed a non‐representational approach to photography concerned with affordances, actor‐networks, hybridized practices and networked flows of photographs. The article falls in three parts. It begins with rethinking photography theory. Traditional dualisms between affordance and practice are challenged, and photography is conceptualized as a hybridized, embodied performance. How digital photography changes photography's traditional affordances is then discussed. The third part discusses various methods to describe how affordances of digital tourist photography are used, twisted and resisted in concrete hybridized practices. I suggest undertaking multi‐sided ethnographies with ‘busy photographers’ to craft non‐representational accounts of mobile practices of photographing and flows of photographic images across various sites and actor‐networks. In a broader sense, this article is a methodological contribution to ‘the new mobilities paradigm’.     

参差重复频率分析和设计

雷达工作于脉冲工作状态时不可避免的会出现盲速现象。可通过参差重频的方法减少盲速带来的影响。在推导频率响应的基础上,该文采用最优化设计的方法进行参差周期的设计,详细考虑并推导得到了最优化搜索中几个重要参数,给出了其解析表达式。仿真结果和频率响应图表明,该方法得到的参差周期能将慢速扩大到原来盲速的数倍以上,有效地减少了盲速的影响。     

The Effect of Firm and Host Country Characteristics on the Choice of Entry Mode: Empirical Evidence from Spanish Firms

When investing abroad firms must choose betweengoing alone or with a partner – the so-calledownership structure decision. Additionally,firms can enter a new country by acquisitionsor by greenfield investments – the foreignestablishment mode decision. These twodecisions have traditionally been analyzedseparately in the literature on entry mode.What is more, this literature has much lessanalyzed hybrid entry modes, like partialacquisitions. The aim of this paper is toanalyze how the different factors analyzed inprior research influence the choice of entrymode when jointly taking into account fouralternative entry modes: greenfield whollyowned subsidiaries, greenfield joint ventures,full acquisitions and partial acquisitions. Theempirical analysis was carried out byestimating a multinomial logit model over asample of FDIs made by Spanish firms. Ourresults also contribute to the knowledge ofspecific patterns in the choice of entry modeby firms from late investor countries, likeSpain.     

低频度事件保险产品选择谈判决策模型

本文考虑在低频度事件中保险产品选择问题,用效用理论及模糊数学知识建立了产品选择模型,并给出了算例,找到了使双方均满意的最优产品。     

数字化时代与“艺术终结”论（笔谈）——艺术的黄昏与黎明

数字化时代,为文学艺术的发展开辟了广阔的发展空间,创造了前所未有的新的条件.它不仅要求艺术家做一个现代人,换脑、换笔,更新知识结构,而且要求艺术家在继承人类优秀文艺传统的基础上,更加自觉地掌握现代艺术的特点和规律,创造出无愧于新的时代的艺术珍品.艺术的终结,恰恰是艺术新生的起点,艺术的黄昏则是艺术的黎明的前夜.     

论跨国公司对华投资战略调整

"入世"后,随着我国投资环境的进一步改善,跨国公司对华投资呈现出一系列新特点,投资规模、投资方式、投资领域等都发生了一些新变化。本文就其变化的趋势以及可能对我国经济产生的影响进行了分析。这对在新形势下进一步改善投资环境,积极引进外资以促进我国经济健康稳定地发展有一定的现实意义。