Improved Heterogeneous Distance Functions

Instance-based learning techniques typically handle continuous and linear input values well, but often do not handle nominal input attributes appropriately. The Value Difference Metric (VDM) was designed to find reasonable distance values between nominal attribute values, but it largely ignores continuous attributes, requiring discretization to map continuous values into nominal values. This paper proposes three new heterogeneous distance functions, called the Heterogeneous Value Difference Metric (HVDM), the Interpolated Value Difference Metric (IVDM), and the Windowed Value Difference Metric (WVDM). These new distance functions are designed to handle applications with nominal attributes, continuous attributes, or both. In experiments on 48 applications the new distance metrics achieve higher classification accuracy on average than three previous distance functions on those datasets that have both nominal and continuous attributes.Comment: See http://www.jair.org/ for an online appendix and other files accompanying this articl

Assessing Euro-Med Trade Preferences: The Case of Entry Price Reduction

The EU protects some of its fruits and vegetables through the entry price system. This system consists on a two-tiered tariff, with high-priced exports paying an ad valorem tariff, whereas low-priced exports pay also a supplementary specific tariff. The breaking point between high and low export prices is the entry price level decided by the EU, generally the same level for all third countries. In a few cases, some Southern Mediterranean partners of the EU have agreed a reduced entry price for their exports, together with the more common ad valorem tariff reduction. Among the indicators used for gauge the value of preferences, there is no one devoted to this case of reduced entry price, hence we develop a new indicator that allows to split which part of the preferential gains corresponds to the entry price reduction and which part corresponds to the "usual" ad valorem tariff reduction. We apply this methodology to Moroccan clementines trade flows, with two main findings: 1) The entry price reduction ranges up to 39% of the economic value of preferences in some months; 2) Morocco is not maximizing the gains due to this reduction, and could take some trade and policy lessons, mainly trying to better fit to the concession or, if impossible, use it as negotiating capital in future reviews of the agreement.International Relations/Trade,