Foam: A General purpose Monte Carlo Cellular Algorithm

A general-purpose, self-adapting Monte Carlo (MC) algorithm implemented in the program {\tt Foam} is described. The high efficiency of the MC, that is small maximum weight or variance of the MC weight is achieved by means of dividing the integration domain into small cells. The cells can be $n$-dimensional simplices, hyperrectangles or a Cartesian product of them. The grid of cells, ``foam'', is produced in the process of the binary split of the cells. The next cell to be divided and the position/direction of the division hyperplane is chosen by the algorithm which optimizes the ratio of the maximum weight to the average weight or (optionally) the total variance. The algorithm is able to deal, in principle, with an arbitrary pattern of the singularities in the distribution.Comment: ICHEP 2002 tal

The link between mobile telephony arrears and credit arrears

At the request of the Minister for Climate and Energy, Paul Magnette, who is also responsible for Consumer Affairs, the NBB's Microeconomic Analysis Service conducted an investigation into the link between payment arrears for mobile telephony and arrears on loan repayments. In this inquiry, which was carried out using data drawn from the Preventel records and from the Central Individual Credit Register, the profile of people with arrears for both types of debt was also analysed. The profile analysis shows that defaulters with a Preventel registration form a specific group among CICR defaulters. People with payment arrears for both types of debt tend to have a demographic and credit profile which to a large extent matches that of CICR defaulters with no mobile phone payment arrears, but a few differences were also found between both groups of defaulters. A number of trends in borrowing and repayment behaviour turn out to be much more pronounced in the first of these two defaulter groups, but it is above all in regard to the age aspect that the differences are most striking. In cases where people have fallen behind in their payments for both types of debt, it actually turns out to be a younger group. Generally speaking, these borrowers take out their first loan at an earlier age, and they also tend to run up their first arrears when they are younger. The inquiry further revealed that there is a statistically significant link between payment arrears for mobile telephony and credit arrears, and this applies for various definitions of payment arrears. Repayment problems generally tend to emerge sooner in payment arrears for mobile telephony bills than in arrears on loans. A simple logistic regression model indicates that dummy variables for a Preventel registration, and for the duration of that registration, still have a definite predictive value with regard to credit arrears, after controlling for a number of demographic and credit variables in the model. As the assessment of the credit risk of private individuals is based on a set of socio-economic variables, payment arrears for mobile telephony could therefore be a useful complementary variable in that assessment.consumer credit bureau, credits, mobile telephony, payment arrears

Credits to individuals – Analysis of the data recorded by the Central Individual Credit Register

Since 1 June 2003 the file of the Central Individual Credit Register has recorded information relating to all consumer credits and mortgage loans contracted by natural persons for private purposes, as well as any payment defaults resulting from these loans. This registration aims to strengthen the means of preventing the excessive indebtedness of private individuals. On demand of the Accompanying Committee of the Central Individual Credit Register the data of this unique and quasi exhaustive database have been thoroughly analysed in 2005. In the article, some of the results of that analysis, which was published in January 2006 in Working Paper n° 78, are given. More specifically, the article investigates borrowing and payment behavior according to debtor characteristics. The analysis finds that borrowing patterns, especially as credit portfolio composition is concerned, clearly diverge according to age and residence. Furthermore, striking differences were found for the percentage of loan defaults if these variables were taken into account. In particular, the article comes to the conclusion that loan defaults aggregated at the regional level show remarkably strong correlations with economic and demographic factors.credit bureau, consumer credits, mortgage loans, loan payment defaults

Sensorimotor Processing in Post-Stroke Fatigue

Chronic pathological fatigue is a highly debilitating symptom with a significant impact on quality of life of stroke survivors. Despite its high prevalence, research into the mechanisms that underlie post-stroke fatigue is lacking. This thesis outlines how changes in cortical neurophysiology results in alterations in sensorimotor processing associated with the perception of effort and how prolonged experience of high effort can subsequently result in chronic pathological fatigue. I show that the perception of effort for what are usually low effort activities is altered in non-depressed, chronic stroke survivors with minimal physical impairment. Low effort voluntary contractions are perceived as more effortful in stroke survivors with high fatigue compared to those with low fatigue. Sensory attenuation, the ability to attend away from predictable sensory input, is thought to underlie altered effort perception. If one is unable to attend away from predictable sensory input associated with a voluntary movement, this will give rise to the perception of higher effort afforded to the movement. I show that stroke survivors with high fatigue do not show reduced sensory attenuation of sensory input arising from mechanoreceptors as quantified using a force matching task and suggest that high effort afforded to simple voluntary movements may be a result of reduced sensory attenuation of information arising from within the body, namely proprioceptive afferent information from the contracting muscle. Using TMS, I show that cortical excitability both at rest and during movement preparation is altered in stroke survivors with high fatigue and propose that cortical excitability reflects the degree of sensory attenuation at the level of the sensorimotor cortex. Finally, I show that neuromodulatory techniques such as transcranial direct current stimulation, are potential tools that can be used to reduce fatigue severity by potentially resetting cortical neurophysiology and reducing perceived effort. Overall, the data provides some evidence in support of the sensory attenuation model of fatigue and provides a novel insight into the mechanisms implicated in post- stroke fatigue