Predicting Belgium’s GDP using targeted bridge models. National Bank of Belgium Working Paper No. 290

This paper investigates the usefulness, within the frameworks of the standard bridge model and the ‘bridging with factors’ approach, of a predictor selection procedure that builds on the elastic net algorithm. A pseudo-real time forecasting exercise is performed, in which estimates for Belgium’s quarterly GDP are generated using a monthly dataset of 93 potential predictors. While the simulation results indicate that specifying forecasting models using this procedure can lead to a slight improvement in terms of predictive accuracy over shorter horizons, the forecasting errors made by these ‘targeted’ models are not found to be significantly different from those based on the principal components extracted from the entire set of available indicators. In other words, the only advantage of following such an approach lies in the fact that it enables the forecaster to streamline the information set

Importance et évolution des investissements directs en Belgique

The aim of this study is to give an overview of recent developments in Belgium’s direct investment relations with the rest of the world. The analysis is based mainly on two sets of statistics drawn up by the National Bank of Belgium, namely, data on direct investment flows from the balance of payments on the one hand, and the results of an annual survey on direct investment carried out among Belgian companies, on the other. Foreign direct investment (FDI) flows between Belgium and the rest of the world have, broadly speaking, followed relatively similar trends to FDI flows observed worldwide, but at the same time have shown some specific characteristics, such as the influence of a few sporadic operations involving large amounts and significant differences within the various components making up FDI inflows and outflows, the former consisting essentially of capital injections in companies and the latter mainly taking the form of intercompany loans. This particular structural pattern stems from the presence of the coordination centres in Belgium and the special tax status that these companies enjoy. Apart from those investment flows attributable to the coordination centres, a large part of the FDI inflows recorded in the balance of payments concern investment by multinationals in third countries, for which resident companies act as intermediaries. Still disregarding funds invested in the coordination centres, the total figures compiled on the basis of the annual survey show that foreign shareholdings in Belgian firms, as measured on the basis of their book value, have stabilized since 2002. Moreover, statistics for subsidiaries of foreign companies established in Belgium show that there is still a fairly high proportion of them active in relatively labour-intensive industrial sectors. As for Belgium’s FDI, the results of the direct investment survey point to a gradual expansion in Belgian companies’ activities abroad, which are developing at a faster pace than their domestic business. Both data on outstanding equity and those for subsidiaries abroad indicate that foreign direct investment by resident firms is largely concentrated in other developed countries with similar economic features to Belgium’s. This would tend to suggest that the extent of straight business relocations to low-wage countries by Belgian firms via investments abroad remains relatively limited.Foreign direct investments

The productivity and export spillovers of the internationalisation behaviour of Belgian firms

This paper analyses to what extent the decision to start exporting may be subject to spillovers of the internationalisation behaviour of other (foreign and domestic) firms. We distinguish between two possible channels: effects on productivity and effects on the perceived level of sunk costs of exporting. For both channels, we consider geographical and activity or industry-based linkages between firms. For a sample Belgian firms we find evidence of significant spillovers on productivity as well as productivity-independent spillovers on the decision to start exporting. Spillovers seem more substantial in the geographical dimension than in terms of competitor, client or supplier links, except for the impact of multinationals on the productivity of domestic firms.Export, FDI, spillovers, sunk cost, region

XCSP3-core: A Format for Representing Constraint Satisfaction/Optimization Problems

In this document, we introduce XCSP3-core, a subset of XCSP3 that allows us to represent constraint satisfaction/optimization problems. The interest of XCSP3-core is multiple: (i) focusing on the most popular frameworks (CSP and COP) and constraints, (ii) facilitating the parsing process by means of dedicated XCSP3-core parsers written in Java and C++ (using callback functions), (iii) and defining a core format for comparisons (competitions) of constraint solvers.Comment: arXiv admin note: substantial text overlap with arXiv:1611.0339

Post-mortem (re)distribution of 3,4-methylenedioxymethamphetamine (MDMA, 'Ecstasy') : human and animal data

In this paper, the distribution and redistribution of the amphetamine derivative, 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) is brought into focus. Animal experimental data were compared with internationally reported MDMA-related human fatalities: in general, these turned out to be parallel with each other. Due to its inherent properties (e. g. significant volume of distribution), MDMA is liable to postmortem redistribution. Indeed, very high concentrations have been found in cardiac blood and tissues located centrally in the body (blood-rich organs such as lungs and liver in particular). This confirms that post-mortem redistribution due to diffusion from higher to lower concentration can easily take place, mainly at longer post-mortem intervals and when putrefaction occurs. Therefore, we can conclude that for post-mortem quantitation of amphetamine and derivatives, and MDMA in particular, peripheral blood sampling (e. g. femoral vein) remains compulsory. However, if the latter is impossible, MDMA quantification in a few alternative matrices such as vitreous humour and iliopsoas muscle may provide additional information to come to a reliable conclusion. Furthermore, it should be stressed that - at present - it is impossible to estimate the individual susceptibility to the various possible adverse effects of MDMA, which implies that it is impossible to provide a "safe" or "therapeutic" blood MDMA level. Therefore, in current forensic practice, the post-mortem pathological and toxicological findings should form an entity in order to draw a well-grounded conclusion

Functionally Fractal Urban Networks: Geospatial Co-location and Homogeneity of Infrastructure

Just as natural river networks are known to be globally self-similar, recent research has shown that human-built urban networks, such as road networks, are also functionally self-similar, and have fractal topology with power-law node-degree distributions (p(k) = a k). Here we show, for the first time, that other urban infrastructure networks (sanitary and storm-water sewers), which sustain flows of critical services for urban citizens, also show scale-free functional topologies. For roads and drainage networks, we compared functional topological metrics, derived from high-resolution data (70,000 nodes) for a large US city providing services to about 900,000 citizens over an area of about 1,000 km2. For the whole city and for different sized subnets, we also examined these networks in terms of geospatial co-location (roads and sewers). Our analyses reveal functional topological homogeneity among all the subnets within the city, in spite of differences in several urban attributes. The functional topologies of all subnets of both infrastructure types resemble power-law distributions, with tails becoming increasingly power-law as the subnet area increases. Our findings hold implications for assessing the vulnerability of these critical infrastructure networks to cascading shocks based on spatial interdependency, and for improved design and maintenance of urban infrastructure networks