ESTIMATION OF DISCRETE CHOICE MODELS WITH MINIMAL VARIATION OF ALTERNATIVE-SPECIFIC VARIABLES

The paper states conditions for minimal variation within the explanatory variables such that the maximum likelihood estimate of the coefficient vector in the discrete choice logit model is unique. Special emphasis is given to the case that (almost) all individuals observe the same set of alternative-specific explanatory variables. The aspect of ‘experimental design’ in discrete choice models is discussed.     

The impact of the EU sugar trade reform on poor households in developing countries: A general equilibrium analysis

We use a modified version of the applied general equilibrium model GTAP, called GTAP_MH, to evaluate the impact of a reduction in the EU's support price for sugar on income distribution of African households. For LDC countries, non-ACP but participant in the EBA initiative a +2% change is indicated in term of income generation across all ten social strata identified within GTAP_MH framework, with positive percentage changes in supply prices at household level of endowment commodities, and positive percentage changes in price indices for private household expenditures. The big losers will be those countries that would no longer be able to compete at an international level as a result of the lost preferences.     

基于门禁报警系统的研究

门禁报警系统即为出入口门禁安全管理系统,是新型现代化安全管理系统,它集微机自动识别技术和现代安全管理措施为一体,涉及电子,机械,光学,计算机技术,通讯技术等诸多新技术.本系统主要由电子密码锁和红外报警两部分电路组成.电子密码 锁电路由STC89C52单片机系统、矩阵键盘和LCD液晶模块组成.通过矩阵键盘和LCD液晶模块实现人机对话,能完成开锁、密码输入错误时报警、超次锁定、管理员解密、设定用户密码等基本的密码锁的功能.红外报警电路由STC89C52单片机系统、HS0038红外传感器、A/D7705和放大电路组成.当人非法进入时,人体发射的10μm左右的红外线被HS0038红外传感器探测到,产生的信号送入单片机系统处理并产生报警信号,实现防盗报警功能.     

Luck or cheating? A field experiment on honesty with children

We run an experiment to study the relationship between honesty, age and self-control. We focus on children aged between 5 and 15 as the literature suggests that self-control develops within such age range. We ask each child to toss a fair coin in private and to record the outcome (white or black) on a paper sheet. We only reward children who report white. Although we are unable to tell whether each child was honest or not, we speculate about the proportion of reported white outcomes. Children report the prize-winning outcome at rates statistically above 50% but below 100%. Moreover, the probability of cheating is uniform across groups based on child’s characteristics, in particular age. In a second treatment we explicitly tell children not to cheat. This request has a dampening effect on their tendency to over-report the prize-winning outcome, especially in girls. Furthermore, while this effect in boys is constant with age, in girls it tends to decrease with age.     

为何美国的中国史研究新潮迭出?——再析中外学术兴趣之异同

本文的重点是讨论西方中国学的传承和新潮,侧重分析西方学者如何研究和解释中国的历史。中国改革开放以来,西方学者的中国史研究著作,不断在中国翻译出版,引起了许多注意。一般而言,中国学者对于西方同行层出不穷的新颖观点,颇感兴趣。作者认为,西方研究中国史的学者之所以擅长推陈出新,主要有两个原因。一是他们虽然研究中国史,但其历史研究的观点和方法,则常常受到中国史以外领域的启发。二是他们在材料的开发上面,其实还常常受惠于中国学者和出版界,比如中国档案的开放和编辑出版的原始史料等等。换言之,全球化的高歌猛进,使得学术交流比以往更为便利,因而造成了国际中国史学界新潮迭出的现象。     

Confidence intervals for dose or treatment effect in several 2 × j tables

Consider dichotomous observations taken from T strata or tables, where within each table, the effect of J>2 doses or treatments are valuated. 'Ihe dose or treatment effect may be measured by various functions of the probability of outcomes, but it is assumed that the effect is the same in each table. Previous work on finding confidence intervals is specific to a particular function of the probabilities, based on only two doses, and limited to ML estimation of the nuisance parameters. In this paper, confidence intervals are developed based on the C, test, allowing for a unification and generalization of previous work. A computational procedure is given that minimizes the number of iterations required. An extension of the procedure to the regression framework suitable when there are large numbers of sparse tables is outlined.     

基于Vega API与ArcGIS engine的三峡库区景观浏览系统

本文以三峡库区河流景观场景为实验对象,介绍了一种河流VRGIS的设计思想与概要实现方法。在综合二维空间数据、三维空间数据和属性数据的基础上,提供库区人机交互的景观浏览功能和数据查询功能。通过Vega和ArcGIS的结合,开发出一个简单实用的VRGIS,既能作为库区管理规划的平台,又能为旅游宣传提供一种新的途径。     

中小企业B2C商务网站构建模式分析与对策研究

B2C商务网站在企业电子商务的发展中起到非常重要的作用,研究中小企业如何决策选择一种合适的B2C商务网站构建模式,具有重要的应用价值。B2C电子商务网站构建模式有自建、虚拟主机、主机托管、租用公共服务平台、ASP外包5种形式,它们各有其自身的特征,应用SWOT分析法,我们可以发现企业的经济实力、信息化水平、技术力量、所在行业及产品特点等方面都是B2C商务网站构建模式的决策因素。中小企业根据自身特点和不同类型,可以提出基于不同战略的构建B2C商务网站模式的相应对策。     

EU regional convergence and policy: Does the concept of region matter?

Regional convergence has become a heated topic in the last decades. To address it, most papers define regions on the base of normative/administrative criteria, although some consider that it could lead to misleading conclusions. In view of that, this article explores, over the period 1995–2006, the per capita income distribution of two sets of European regions: administrative (NUTS2) and functional (Metropolitan) regions. From a methodological point of view, a distribution dynamics approach – examining the external shape and movements within these distributions – is applied to analyse the issue of convergence. The study does reveal the presence of a process of convergence across both types of regions; however, this seems to be more rapid with Metropolitan than NUTS2 regions, which prompt us to proposing some relative major changes in the EU regional policy.