A niching memetic algorithm for simultaneous clustering and feature selection

Clustering is inherently a difficult task, and is made even more difficult when the selection of relevant features is also an issue. In this paper we propose an approach for simultaneous clustering and feature selection using a niching memetic algorithm. Our approach (which we call NMA_CFS) makes feature selection an integral part of the global clustering search procedure and attempts to overcome the problem of identifying less promising locally optimal solutions in both clustering and feature selection, without making any a priori assumption about the number of clusters. Within the NMA_CFS procedure, a variable composite representation is devised to encode both feature selection and cluster centers with different numbers of clusters. Further, local search operations are introduced to refine feature selection and cluster centers encoded in the chromosomes. Finally, a niching method is integrated to preserve the population diversity and prevent premature convergence. In an experimental evaluation we demonstrate the effectiveness of the proposed approach and compare it with other related approaches, using both synthetic and real data

Launching the Grand Challenges for Ocean Conservation

The ten most pressing Grand Challenges in Oceans Conservation were identified at the Oceans Big Think and described in a detailed working document:A Blue Revolution for Oceans: Reengineering Aquaculture for SustainabilityEnding and Recovering from Marine DebrisTransparency and Traceability from Sea to Shore:  Ending OverfishingProtecting Critical Ocean Habitats: New Tools for Marine ProtectionEngineering Ecological Resilience in Near Shore and Coastal AreasReducing the Ecological Footprint of Fishing through Smarter GearArresting the Alien Invasion: Combating Invasive SpeciesCombatting the Effects of Ocean AcidificationEnding Marine Wildlife TraffickingReviving Dead Zones: Combating Ocean Deoxygenation and Nutrient Runof

Taxation and International Migration of Superstars: Evidence from the European Football Market

This paper analyzes the effects of top earnings tax rates on the international migration of football players in Europe. We construct a panel dataset of top earnings tax rates, football player careers, and club performances in the first leagues of 14 Western European countries since 1985. We identify the effects of top earnings tax rates on migration using a number of tax and institutional changes: (a) the 1995 Bosman ruling which liberalized the European football market, (b) top tax rate reforms within countries, and (c) special tax schemes offering preferential tax rates to immigrant football players. We start by presenting reduced-form graphical evidence showing large and compelling migration responses to country-specific tax reforms and labor market regulation. We then develop a multinomial regression framework to exploit all sources of tax variation simultaneously. Our results show that (i) the overall location responses to the net-of-tax rate is positive and large, with an elasticity of the number of foreign players to the net-of-tax rate around one (and an elasticity of the number of domestic players around .15), (ii) location elasticities are even larger at the top of the ability distribution, but negative at the bottom due to ability sorting effects, and (iii) cross-tax effects of foreign players on domestic players (and vice versa) are negative and quite strong due to displacement effects. Those results can be rationalized in a simple model of migration and taxation with rigid labor demand.

ILR Research in Progress 2003-04

The production of scholarly research continues to be one of the primary missions of the ILR School. During a typical academic year, ILR faculty members published or had accepted for publication over 25 books, edited volumes, and monographs, 170 articles and chapters in edited volumes, numerous book reviews. In addition, a large number of manuscripts were submitted for publication, presented at professional association meetings, or circulated in working paper form. Our faculty's research continues to find its way into the very best industrial relations, social science and statistics journals.Research_in_Progress_2003_04.pdf: 19 downloads, before Oct. 1, 2020

From a Competition for Self-Driving Miniature Cars to a Standardized Experimental Platform: Concept, Models, Architecture, and Evaluation

Context: Competitions for self-driving cars facilitated the development and research in the domain of autonomous vehicles towards potential solutions for the future mobility. Objective: Miniature vehicles can bridge the gap between simulation-based evaluations of algorithms relying on simplified models, and those time-consuming vehicle tests on real-scale proving grounds. Method: This article combines findings from a systematic literature review, an in-depth analysis of results and technical concepts from contestants in a competition for self-driving miniature cars, and experiences of participating in the 2013 competition for self-driving cars. Results: A simulation-based development platform for real-scale vehicles has been adapted to support the development of a self-driving miniature car. Furthermore, a standardized platform was designed and realized to enable research and experiments in the context of future mobility solutions. Conclusion: A clear separation between algorithm conceptualization and validation in a model-based simulation environment enabled efficient and riskless experiments and validation. The design of a reusable, low-cost, and energy-efficient hardware architecture utilizing a standardized software/hardware interface enables experiments, which would otherwise require resources like a large real-scale test track.Comment: 17 pages, 19 figues, 2 table

Social capital, labour precariousness and the economic performance. An empirical assessment of the strength of weak ties in Italy

This paper carries out an assessment of the influence that different kinds of social ties exert on labour precariousness, on the state of health of urban environments and on the economic performance in Italy. Overall, the empirical evidence shows that weak ties connecting members of voluntary organizations positively affect the economic performance and the quality of urban ecosystems, differently from strong ties connecting family members and close friends, which, on the other side, are proved to reduce labour precariousness.Social capital, Social networks, Civil society, Economic development, Labour precariousness, Structural Equations Modelling