Validation issues in educational data mining:the case of HTML-Tutor and iHelp

Validation is one of the key aspects in data mining and even more so in educational data mining (EDM) owing to the nature of the data. In this chapter, a brief overview of validation in the context of EDM is given and a case study is presented. The field of the case study is related to motivational issues, in general, and disengagement detection, in particular. There are several approaches to eliciting motivational knowledge from a learner’s activity trace; in this chapter the validation of such an approach is presented and discussed

Statistical validation of simulation models: A case study

Rigorous statistical validation requires that the responses of the model and the real system have the same expected values. However, the modeled and actual responses are not comparable if they are obtained under different scenarios (environmental conditions). Moreover, data on the real system may be unavailable; sensitivity analysis can then be applied to find out whether the model inputs have effects on the model outputs that agree with the experts' intuition. Not only the total model, but also its modules may be submitted to such sensitivity analyses. This article illustrates these issues through a case study, namely a simulation model for the use of sonar to search for mines on the sea bottom. The methodology, however, applies to models in general.Simulation Models;Statistical Validation;statistics

Reducing the Probability of False Positive Research Findings by Pre-Publication Validation - Experience with a Large Multiple Sclerosis Database

*Objective*
We have assessed the utility of a pre-publication validation policy in reducing the probability of publishing false positive research findings. 
*Study design and setting*
The large database of the Sylvia Lawry Centre for Multiple Sclerosis Research was split in two parts: one for hypothesis generation and a validation part for confirmation of selected results. We present case studies from 5 finalized projects that have used the validation policy and results from a simulation study.
*Results*
In one project, the "relapse and disability" project as described in section II (example 3), findings could not be confirmed in the validation part of the database. The simulation study showed that the percentage of false positive findings can exceed 20% depending on variable selection. 
*Conclusion*
We conclude that the validation policy has prevented the publication of at least one research finding that could not be validated in an independent data set (and probably would have been a "true" false-positive finding) over the past three years, and has led to improved data analysis, statistical programming, and selection of hypotheses. The advantages outweigh the lost statistical power inherent in the process

Fractional Euler-Bernoulli beams: theory, numerical study and experimental validation

In this paper the classical Euler-Bernoulli beam (CEBB) theory is reformulated utilising fractional calculus. Such generalisation is called fractional Euler-Bernoulli beams (FEBB) and results in non-local spatial description. The parameters of the model are identified based on AFM experiments concerning bending rigidities of micro-beams made of the polymer SU-8. In experiments both force as well as deflection data were recorded revealing significant size effect with respect to outer dimensions of the specimens. Special attention is also focused on the proper numerical solution of obtained fractional differential equation