The Lane-Curvature Method (LCM) presented in this paper is a new local obstacle avoidance method for indoor mobile robots. The method combines the Curvature-Velocity Method (CVM) with a new directional method called the Lane Method. The lane method divides the environment into lanes, and then chooses the best lane to follow to optimize travel along a desired heading. A local heading is then cal...

The class of closed patterns is a well known condensed representations of frequent patterns, and have recently attracted considerable interest. In this paper, we propose an efficient algorithm LCM (Linear time Closed pattern Miner) for mining frequent closed patterns from large transaction databases. The main theoretical contribution is our proposed prefix-preserving closure extension of closed...

Let S = {x1,x2, . . . ,xn} be a set of positive integers, and let f be an arithmetical function. The matrices (S) f = [ f (gcd(xi,xj))] and [S] f = [ f (lcm[xi,xj])] are referred to as the greatest common divisor (GCD) and the least common multiple (LCM) matrices on S with respect to f , respectively. In this paper, we assume that the elements of the matrices (S) f and [S] f are integers and st...

An important part of a latent class analysis concerns the selection of the number of latent classes. In this paper, we discuss the Bayes factor as a selection tool. The discussion will focus on two aspects: (i) the computation of the Bayes factor and (ii) prior sensitivity. To deal with prior sensitivity, we propose to extend the model with a prior for the hyperparameters. We further discuss th...

In this paper we study the positive definiteness of meet and join matrices using a novel approach. When the set Sn is meet closed, we give a sufficient and necessary condition for the positive definiteness of the matrix (Sn)f . From this condition we obtain some sufficient conditions for positive definiteness as corollaries. We also use graph theory and show that by making some graph theoretic ...

In the context of sustainable consumption buying local produce could support environmentally friendly production from the local economy. Our study estimates the preference weights that local consumers assign to some milk attributes including local origin and the influence on choice of a local brand of milk, which is traded by a local cooperative of producers in Umbria (Italy). Several preferenc...

Verbs were clustered semantically on the basis of their alternation behaviour, as characterised by their syntactic subcategorisation frames extracted from maximum probability parses of a robust statistical parser, and completed by assigning WordNet classes as selectional preferences to the frame arguments. The clustering was achieved (a) iteratively by measuring the relative entropy between the...

Social capital has proven to be a useful concept, but has been ill-defined and not wellmeasured in the economics literature. We propose a different empirical method for measuring social capital, latent class analysis, based on the idea that social capital is an unobservable multidimensional construct. We explain and demonstrate the construction of latent classes that measure an individual’s soc...

We exploit the potential of latent class analysis in order to propose an innovative framework for financial portfolio development. By stressing the latent nature of the most important financial variables, the expected return and the risk, we are able to introduce a methodological dimension in relevant steps of portfolio analysis. First, we provide a test for the number of possible investment ch...

Standard economic theory assumes individuals make decisions over a set of risky domains according to their own risk preferences which are stable across these decision contexts. The validity of this assumption of context-invariant risk preference has led to debate in the literature. We exploit latent class analysis to identify conditional on predicted and realized risk how heterogeneity in risk ...