From the classroom to the computer screen: delivering a traditional University course in a non-traditional way

The present Technical Reports contains two complementary papers describing our experience with a system for delivering traditional lectures through computers and computer networks

Why web pages annotation tools are not killer applications? A new approach to an old problem

The annotation of web pages, and the possibility to share the notes with others, seems to be a powerful tool. Although several tools already provide such possibility, they are not as widely popular as one would expect them to be. We try to explain this fact, and propose a novel architectural approach that is, in our view, particularly suited to some particular domain such as e-learning. We also present a tool that implements the proposed architecture

Composite Likelihood Inference by Nonparametric Saddlepoint Tests

The class of composite likelihood functions provides a flexible and powerful toolkit to carry out approximate inference for complex statistical models when the full likelihood is either impossible to specify or unfeasible to compute. However, the strenght of the composite likelihood approach is dimmed when considering hypothesis testing about a multidimensional parameter because the finite sample behavior of likelihood ratio, Wald, and score-type test statistics is tied to the Godambe information matrix. Consequently inaccurate estimates of the Godambe information translate in inaccurate p-values. In this paper it is shown how accurate inference can be obtained by using a fully nonparametric saddlepoint test statistic derived from the composite score functions. The proposed statistic is asymptotically chi-square distributed up to a relative error of second order and does not depend on the Godambe information. The validity of the method is demonstrated through simulation studies

The clinical meaning of histamine skin reactivity

The definition of the “atopic state”, i.e. subjects presenting at least one skin wheal with a minimum diameter of 3 mm induced by an allergen skin-prick test (ASPT), is based on the assumption that wheal size depends entirely on the amount of histamine produced in the antigen-antibody reaction. Several epidemiological studies have, however, demonstrated that an ASPT-elicited wheal is heavily modulated by “histamine skin reactivity” (HSR), i.e. the size of the wheal induced by a prick test performed with a given solution of histamine. HSR not only varies widely depending on the individual characteristics and geographical setting, but also changes over time; these differences in HSR markedly influence the amount of specific IgE required to produce a wheal of at least 3 mm in an ASPT. We should therefore ideally conceive the existence of two types of” atopic patients”: one type in whom “atopy” is mainly the result of an increased level of specific IgE antibodies, and another type in whom positive ASPTs are mainly the result of marked skin reactivity to even small amounts of histamine. If hyper-reactivity to histamine occurs not only in the skin but in parallel also in other parts of the organism, especially at the mucosal level, “normal” histamine production may cause chronic or recurrent clinical symptom

Feasibility Study of RFID Technology for Construction Load Tracking

INE/AUTC 10.0

A robust approach for skewed and heavy-tailed outcomes in the analysis of health care expenditures

In this paper robust statistical procedures are presented for the analysis of skewed and heavy-tailed outcomes as they typically occur in health care data. The new estimators and test statistics are extensions of classical maximum likelihood techniques for generalized linear models. In contrast to their classical counterparts, the new robust techniques show lower variability and excellent effciency properties in the presence of small deviations form the assumed model, i.e. when the underlying distribution of the data lies in a neighborhood of the model. A simulation study, an analysis on real data, and a sensitivity analysis confirm the good theoretical statistical properties of the new techniques.Deviations from the model; GLM modeling; health econometrics; heavy tails; robust estimation; robust inference