Designing from activities. The "ability /difficulty table", a useful tool to detect the "limit users" in the Design for All Approach

In the Design for All Approach (DfA), an important phase of the design process consists in the individuation of the so-called "limit users", that are that particular group of people with the most "critical" features for the autonomous fruition of a system or a product. Generally, however, it is not easy to identify them in a complete and objective way. A clear and complete outline of design requirements with respect to the "normal" use of a service, product or environment, moreover, is of fundamental importance in inclusive design. In fact, we know how bad design, that doesn't take in account the true "strategies of use", may lead to situations of handicap, also serious, temporary or permanent, regardless if the user is a "disabled" person or not. In relation to this scenario, the paper shows the results of a research which has developed the "Ability/Difficulty Table" ("A/D Table"), a new tool useful to identify the so-called "limit users" and their needs with respect to different activities, linking the main "difficulties", expressed by people, with the "abilities" required to carry out in autonomy the investigated activity.     

基于次梯度投影的泛投资组合选择策略

在线投资组合选择(online portfolio selection)问题是当前量化投资领域一个重要的研究问题.近些年来,可投资标的的爆炸式增长急需能够有效计算的投资组合选择策略,而现有高绩效算法大多具有指数级或多项式级的时间复杂度,不利于在实际中应用.由此,本文提出了一种基于次梯度投影的泛投资组合选择策略SGP.将次梯度投影的思想应用到资产组合构建的过程中,得到策略的再平衡规则.理论上,本文分析了次梯度投影算法的竞争性能,证明了该策略是一个泛投资组合选择策略;并发现该算法具有线性时间复杂度.实证上,验证了SGP策略在美国与中国市场的表现.结果表明,SGP策略能够实现和最新的泛投资组合选择策略相当的收益率,而算法运行时间短于现有策略.参数敏感性分析表明SGP策略对参数选择不敏感;交易成本敏感性分析表明SGP策略能够承受合理的交易成本.     

高层领导者心理资本和社会资本对企业绩效的影响研究

通过对968位不同企业的高层领导者的问卷分析,检验了企业高层领导者心理资本和社会资本对企业绩效的影响,以及风险承担行为的中介作用.研究结果表明,企业高层领导者心理资本和社会资本对企业绩效与风险承担行为具有显著的正向影响;其风险承担行为对企业绩效具有显著的直接功效,且风险承担行为在高层领导者心理资本和社会资本对企业绩效的影响路径中起部分中介作用,即高层领导者心理资本和社会资本通过风险承担行为对企业绩效具有一定的间接功效.     

中国传统的非逻辑思维方式对博士生创造性思维生成的启示

非逻辑思维是中国传统思维的组成部分,它内含着重要的创造性品质,这种创造性品质对于当代博士生提高创造性思维能力具有重要意义。     

战后日本学术界近代中国东北史研究述评

日本学界在战前就十分关注对中国东北地区的研究，战后则经过五十至七十年代的复苏休整，八、九十年代以来形成近代东北史研究的繁荣局面，在各种新的理论方法的影响下，取得了令人瞩目的成就，其经验与教训值得我国学者学习与借鉴。     

试论“摸起来”与“摸上去”

感官动词"摸"所构成的动补结构"摸起来"、"摸上去",二者在语义、句法、语用、单位性质等方面存在着异同。两者在语法单位性质上根据二者语义的不同可视为短语或正向词过渡的短语。     

The Protective Impact of a Covariate on Competing Failures with an Example from a Bone Marrow Transplantation Study

Starting from an applied Bone Marrow Transplantation(BMT) study, the problem of “unexpected protectivity” in competing risks models is introduced, which occurs when one covariate shows a protective impact not expected from a medical perspective. Current explanations found in the statistical literature suggest that unexpected protectivity might be due to the lack of independence between the competing failures. Actually, in the presence of dependence, the Kaplan-Meier curves are not interpretable. Conversely, the cumulative incidence curves remain interpretable, and therefore seem to be a candidate for solving the problem. We discuss the particular nature of dependence in a competing risks framework and illustrate how this dependence may be created via a common frailty factor. A Monte Carlo experiment is set up which accounts also for the association between the observable covariates and the frailty factor. The aim of the experiment is to understand whether and how the bias showed by the estimates could be related to the omitted frailty variable. The results show that dependence alone does not cause false protectivity, and that the cumulative incidence curves suffer the same bias as the survival curves and therefore do not seem to be a solution to false protectivity. Conversely, false protectivity may occur according to the magnitude and the sign of the dependence between the frailty factor and the covariate. The paper ends with some suggestions for empirical research. This revised version was published online in July 2006 with corrections to the Cover Date.     

论我国土地宏观调控

土地宏观调控是政府以土地作为手段调控宏观经济运行的政策和措施的综合。我国已将土地宏观调控作为宏观经济调控的重要手段之一。分析了我国实行土地宏观调控的主要动因,论述了我国土地宏观调控的主要内容,提出了提高土地宏观调控政策效果的措施。     

特种Nafion溶液制备及其在PEMFC中的应用研究

Nafion溶液在燃料电池、电极修饰、电化学分析、电化学催化等领域具有广泛用途。采用特种高沸点溶剂,获得了溶铸性能优良Nafion的溶液。比较溶铸Nafion膜与原始Nafion膜的IR光谱可以看出,Nafion溶液制备方法未对Nafion膜的化学组成与分子结构产生影响,但溶铸膜的分子排列更加规整有序。将该溶液在PEMFC中应用,其性能优于目前的商品水-醇体系Nafion溶液。