64,789 research outputs found

    RDF-TR: Exploiting structural redundancies to boost RDF compression

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    The number and volume of semantic data have grown impressively over the last decade, promoting compression as an essential tool for RDF preservation, sharing and management. In contrast to universal compressors, RDF compression techniques are able to detect and exploit specific forms of redundancy in RDF data. Thus, state-of-the-art RDF compressors excel at exploiting syntactic and semantic redundancies, i.e., repetitions in the serialization format and information that can be inferred implicitly. However, little attention has been paid to the existence of structural patterns within the RDF dataset; i.e. structural redundancy. In this paper, we analyze structural regularities in real-world datasets, and show three schema-based sources of redundancies that underpin the schema-relaxed nature of RDF. Then, we propose RDF-Tr (RDF Triples Reorganizer), a preprocessing technique that discovers and removes this kind of redundancy before the RDF dataset is effectively compressed. In particular, RDF-Tr groups subjects that are described by the same predicates, and locally re-codes the objects related to these predicates. Finally, we integrate RDF-Tr with two RDF compressors, HDT and k2-triples. Our experiments show that using RDF-Tr with these compressors improves by up to 2.3 times their original effectiveness, outperforming the most prominent state-of-the-art techniques

    The impact of productive efficiency and quality of a regulated local public utility on final goods prices and consumers welfare

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    In this paper, we reconstruct the process by which the decisions of a regulated local public utility, in terms of productive efficiency and quality of the service provided, impact on prices of final consumption goods, supplied in a oligopolistic market operating in the same geographic area. We obtain some formula for these effects which can be quantified by estimating firms’ conditional input demand function of the public service and firms’ inverse demand function for this public good, non-rival, component. Finally, we draw the effects of productive efficiency and quality on consumer welfare and cost-of-living, via changes on tariffs, external effects and final goods prices.regulation, x-efficiency, oligopoly, consumer welfare

    A New Fiscal Pact, Tax Policy Changes and Income Inequality

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    The paper analyses the changes in tax policy, tax/GDP ratios, tax incidence and income inequality which have taken place in Latin America during the last decade against the background of the changes observed in these variables during the liberal years of the 1980s and 1990s. The paper argues that the recent tax policy changes and a favourable external environment led to an increase of about three points in the regional tax/GDP ratio, that such increase in taxation took place in a slightly or substantially more progressive way than in the past, that the Gini coefficient of the distribution of household income improved on average by 0.4-0.8 points, and that, as a result, redistribution via taxation improved (especially in the Southern Cone) in relation to the 1990s thanks to greater reliance on direct taxes and a reduction in excises. However, in the mid-late 2000s taxation remains unequalizing in about a third of the countries of the region, especially in Central America. The paper concludes by offering recommendations on how the new fiscal pact evolving in the region can be strengthened to improve the redistributive effect of taxation in the years ahead.tax policy, tax incidence, income inequality, redistribution, fiscal exchange, Latin America

    A note on information revelation in procurement auctions

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    This paper is about a procurement auction setting, introduced in Gal-Or, Gal-Or and Dukes (2007), in which suppliers offer differentiated products and the buyer needs to decide whether to reveal or not to the suppliers the own preferences for the various products. We provide some technical remarks and complements to the analysis of Gal-Or, Gal-Or and Dukes (2007), and an extension to the case of risk averse suppliers.Information Revelation, Logconcavity, Risk Aversion

    Migration and non farm activities as income diversification strategies: the case of Northern Ghana

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    Environmental changes affect the livelihood of the rural population. This is especially true for those households who mainly rely on farming for their subsistence. In Northern Ghana, during the last two decades, soil erosion, the increasing unpredictability of the rains and the raise in the population size - with the ensuing pressure on the land - contributed to make people even more vulnerable to environmental conditions. These factors - together with the adverse market conditions for the local produce and the neglect of the region in the design of adjustment policies - pushed rural population towards income generating activities alternative to farming (i.e. migration and non farm activities). In this paper, we use a multivariate analysis to explore the determinants of income diversification from a household perspective. We find that non agricultural activities represent an option that better-off households - and communities - can resort to, in order to overcome the difficulties of the agricultural sector; while out-rural seasonal migration is emerging as a coping strategy adopted by poor households to meet their basic needs, and it is unlikely to improve their socioeconomic condition in the long run.income diversification, poverty, inequality, migration

    The Austrian School on Happiness and Relational Goods

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    Austrian economists do not directly face the problem of the relationships between economics and happiness. They even rather rarely use the word happiness and do not bother to define the philosophical meaning of it referring to Aristotle or to the Enlightenment. They prefer to speak of human welfare: a comprehensive welfare, not limited to the satisfaction of material needs. The problem that they directly face is whether and in what sense non-instrumental human relationships (that is relational goods) can be considered and dealt with as economic goods increasing human welfare. In this way, they indirectly explore the theme of the relationships between economics and happiness.Austrian School, Economics and Happiness, Well-Being, Relational Goods

    Model Theory and Entailment Rules for RDF Containers, Collections and Reification

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    An RDF graph is, at its core, just a set of statements consisting of subjects, predicates and objects. Nevertheless, since its inception practitioners have asked for richer data structures such as containers (for open lists, sets and bags), collections (for closed lists) and reification (for quoting and provenance). Though this desire has been addressed in the RDF primer and RDF Schema specification, they are explicitely ignored in its model theory. In this paper we formalize the intuitive semantics (as suggested by the RDF primer, the RDF Schema and RDF semantics specifications) of these compound data structures by two orthogonal extensions of the RDFS model theory (RDFCC for RDF containers and collections, and RDFR for RDF reification). Second, we give a set of entailment rules that is sound and complete for the RDFCC and RDFR model theories. We show that complexity of RDFCC and RDFR entailment remains the same as that of simple RDF entailment

    Comparing Human Development Patterns Across Countries: Is it Possible to Reconcile Multidimensional Measures and Intuitive Appeal?

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    The aims of this paper are two. The first is to to present a framework that facilitates the identification and analysis of human development patterns in terms of outcomes performance from a cross and time perspective. The second is to find a method that is effective in summarizing different dimensions that concerns human development progress. We consider human development progress as enhanced throughout virtuous synergies among positive human development outcomes and between these and `positive' economic outcomes. The methodology aims to take into consideration these synergies, while the theoretical framework captures different patterns of human development progress through the distinction between the social dimensions (SD) and the economic dimensions (ED) as `command over resources'. Although this framework is not a sufficient guide for policy, the research findings are an explicit recognition of the need to analyse and to integrate economic and social policies. Furthermore, the explorative empirical results highlight different human development patterns between countries and their connection to the different policies adopted by each country (e.g. by transition economies) and by the impact of different type of crises.Human Development, HDI, Multidimensional Index

    Market Equilibrium in the Presence of Green Consumers and Responsible Firms: a Comparative Statics Analysis

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    This paper analyzes how the interaction between green consumers and responsible firms affects the market equilibrium. The main result is that a higher responsibility by both producers and consumers can have different impacts on the efficiency of the firms' abatement activity, depending on the nature of the cleaning costs. When the abatement costs are fixed, the efficiency of the clean-up effort is always increasing in their degree of responsibility. On the other hand, when the abatement costs are variable, a higher level of responsibility may reduce social welfare. Finally, the first best allocation is never reached, even in the presence of the highest credible level of responsibility of both consumers and producers.Green Consumers, Corporate Social Responsibility, Vertical Differentiation

    'CHOOSER DEPENDANT' PREFERENCES, AND ATTITUDES de se

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    Sen’s 'chooser dependence' of preferences generates issues of indexicality which, we claim, can in fact be reduced to a specification of the content of preferences within a standard approach, by means of Lewis’ theory of attitudes de se. While context sensitivity of preferences can be dealt with by the addition to the outcomes of choice of their relevant mereological contexts, indexical sensitivity requires the content of preferences to include (the nature of) the decision maker him/herself. The result is a naturalistic internalization of preferences, which become object of preference, belief, and action. Keywords: Preferences, utility, choice, attitudes, mereology, properties.
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