Abstract
The design of algorithms that explore multiple representation languages and explore different search spaces has an intuitive appeal. In the context of classification problems, algorithms that generate multivariate trees are able to explore multiple representation languages by using decision tests based on a combination of attributes. The same applies to model trees algorithms, in regression domains, but using linear models at leaf nodes. In this paper we study where to use combinations of attributes in decision tree learning, We present an algorithm for multivariate tree learning that combines a univariate decision tree with a discriminant function by means of constructive induction. This algorithm is able to use decision nodes with multivariate tests, and leaf nodes that predict a class using a discriminant function. Multivariate decision nodes are built when growing the tree, while junctional leaves are built when pruning the tree. Functional trees can be seen as a generalization of multivariate trees. Our algorithm was compared against to its components and two simplified versions using 30 benchmark datasets. The experimental evaluation shows that our algorithm has clear advantages with respect to the generalization ability and model sizes at statistically significant confidence levels.

Abstract
The design of algorithms that explore multiple representation languages and explore different search spaces has an intuitive appeal. In the context of classification problems, algorithms that generate multivariate trees are able to explore multiple representation languages by using decision tests based on a combination of attributes. The same applies to model trees algorithms, in regression domains, but using linear models at leaf nodes. In this paper we study where to use combinations of attributes in regression and classification tree learning. We present an algorithm for multivariate tree learning that combines a univariate decision tree with a linear function by means of constructive induction. This algorithm is able to use decision nodes with multivariate tests, and leaf nodes that make predictions using linear functions. Multivariate decision nodes are built when growing the tree, while functional leaves are built when pruning the tree. The algorithm has been implemented both for classification problems and regression problems. The experimental evaluation shows that our algorithm has clear advantages with respect to the generalization ability when compared against its components, two simplified versions, and competes well against the state-of-the-art in multivariate regression and classification trees. © Springer-Verlag Berlin Heidelberg 2001.

Abstract
The aim of behavioural cloning is to synthesize artificial controllers that are robust and comprehensible to human understanding. To attain the two objectives we propose the use of the Incremental Correction model that is based on a closed-loop control strategy to model the reactive aspects of human control skills. We have investigated the use of three different representations to encode the artificial controllers: univariate decision trees as induced by C4.5; multivariate decision and regression trees as induced by cart and; clausal theories induced by an Inductive Logic Programming (ILP) system. We obtained an increase in robustness and a lower complexity of the controllers when compared with results using other models. The controllers synthesized by cart revealed to be the most robust. The ILP system produced the simpler encodings. © Springer-Verlag Berlin Heidelberg 2001.

Abstract

Abstract
There is a growing interest in understanding consumer ethical actions in relation to their dealings with firms. This paper examines whether there are differences between Northern and Southern European Union (EU) consumers' perceptions of ethical consumer behaviour using Muncy and Vitell's (1992) Consumer Ethics Scale (CES). The study samples 962 university students across four Northern EU countries (Germany, Denmark, Scotland, The Netherlands) and four Southern EU countries (Portugal, Spain, Italy, Greece). Some differences are identified between the two samples, which might question the ability of organisations to consider the EU as one homogeneous market.

Abstract
We propose a model, called Incremental Correction. (IC) model to address the problem of reverse engineering human control skills using the Behavioural Cloning methodology. The proposed model is based on the concept of closed loop or feedback control. The controllers are induced via Machine Learning tools from traces of human expert control performance. Controllers using the IC model exhibit an increase in robustness and a reduction in encoding complexity when compared to previous models used in behavioural cloning.