Complex network analysis and nonlinear dynamics

This chapter aims at reviewing complex network and nonlinear dynamical models and methods that were either developed for or applied to socioeconomic issues, and pertinent to the theme of New Economic Geography. After an introduction to the foundations of the field of complex networks, the present summary introduces some applications of complex networks to economics, finance, epidemic spreading of innovations, and regional trade and developments. The chapter also reviews results involving applications of complex networks to other relevant socioeconomic issue

Complex networks analysis in socioeconomic models

This chapter aims at reviewing complex networks models and methods that were either developed for or applied to socioeconomic issues, and pertinent to the theme of New Economic Geography. After an introduction to the foundations of the field of complex networks, the present summary adds insights on the statistical mechanical approach, and on the most relevant computational aspects for the treatment of these systems. As the most frequently used model for interacting agent-based systems, a brief description of the statistical mechanics of the classical Ising model on regular lattices, together with recent extensions of the same model on small-world Watts-Strogatz and scale-free Albert-Barabasi complex networks is included. Other sections of the chapter are devoted to applications of complex networks to economics, finance, spreading of innovations, and regional trade and developments. The chapter also reviews results involving applications of complex networks to other relevant socioeconomic issues, including results for opinion and citation networks. Finally, some avenues for future research are introduced before summarizing the main conclusions of the chapter.Comment: 39 pages, 185 references, (not final version of) a chapter prepared for Complexity and Geographical Economics - Topics and Tools, P. Commendatore, S.S. Kayam and I. Kubin Eds. (Springer, to be published

Imperfect competition in the fresh tomato industry

In this paper, we analyse the market power of the retail industry in the French tomato market. Following the methods developed in the New Empirical Industrial Organization, we develop a structural model of this industry. The analysis is based on detailed data on final consumption and prices at both shipper and consumer levels for two types of tomatoes in France. The structural model is composed of a system of demand equations, supply equations and pricing equations which include terms which capture the oligopoly and oligopsony power of the retail sector. We show that i) elasticity of demand varies during the year ii) the retail sector exercise only a ‘moderate’ market power iii) the exercise of market power decreases over time iv) If markets were competitive, in the case of tomato ‘ronde’ retail price would decrease by about 1.2% to 4.5% depending on the year; v) In absence of market power, shipping price might be 6% to 24% higher than observed. We find higher distortions in the case of tomato ‘grappe’. We also find that the distortions tend to decrease over time. We conclude to a moderate exercise of market power of the retail sector in the French tomato market.Oligopoly, Oligopsony, Fresh products, Industrial Organization,

Imperfect Competition in the Fresh Fruit and Vegetable Industry

Do retailers exert market power in the fresh fruit and vegetables markets? In the EU countries, as the retail industry distributes a significant part of fruit and vegetables, a non competitive behavior might have significant impact on consumption, on surplus and welfare. In this paper, we shed some light on the degree of non-competitive distortions in the French fresh fruit and vegetable markets. We analyze the market of tomato. The analysis is based on aggregate data on final consumption and prices at both shipper and consumer levels in France. The structural model is composed of a system of demand equations, supply equations and pricing equations which include terms that capture the oligopoly and oligopsony power of the retail sector and that account for product differentiation. We show that: i) elasticity of demand varies during the year ii) the exercise of market power decreases over time iii) if markets were competitive, retail price would decrease by about 2% to 12% depending on the year while shipping price might be 10% to 54% higher than observed. As a general result quantities consumed would not change significantly. We conclude that the retail sector exerts a moderate market power.Oligopsony, oligopoly, retail industry, fruit and vegetable markets., Agricultural and Food Policy,

Robust Speech Detection for Noisy Environments

This paper presents a robust voice activity detector (VAD) based on hidden Markov models (HMM) to improve speech recognition systems in stationary and non-stationary noise environments: inside motor vehicles (like cars or planes) or inside buildings close to high traffic places (like in a control tower for air traffic control (ATC)). In these environments, there is a high stationary noise level caused by vehicle motors and additionally, there could be people speaking at certain distance from the main speaker producing non-stationary noise. The VAD presented in this paper is characterized by a new front-end and a noise level adaptation process that increases significantly the VAD robustness for different signal to noise ratios (SNRs). The feature vector used by the VAD includes the most relevant Mel Frequency Cepstral Coefficients (MFCC), normalized log energy and delta log energy. The proposed VAD has been evaluated and compared to other well-known VADs using three databases containing different noise conditions: speech in clean environments (SNRs mayor que 20 dB), speech recorded in stationary noise environments (inside or close to motor vehicles), and finally, speech in non stationary environments (including noise from bars, television and far-field speakers). In the three cases, the detection error obtained with the proposed VAD is the lowest for all SNRs compared to Acero¿s VAD (reference of this work) and other well-known VADs like AMR, AURORA or G729 annex b

Marcel Duchamp: crítica de la significación. Lo posible y el estilo

El propòsit d'aquest article és el de realitzar una lectura de l'obra de Marcel Duchamp posant-la en relació amb aquell pensament estètic que té com a principals exponents a F. Nietzsche i M. Heidegger i que s'integra en una reflexió més general al voltant dels fonaments de la cultura des d'un punt de vista eminentment lingüístic. Marcel Duchamp convertirà l'art en el mitjà idoni per a elaborar una crítica general de la significació centrant tots els seus esforços en aquell llindar on s'esdevé l'emergència de sentit. És aquí, en aquest lloc privilegiat que hi ha entre la pura possibilitat i la representació on s'ha de resoldre la paradoxa entre creativitat i estil; i és aquí on Marcel Duchamp situa el punt de partida de la consciència contemporània

O pacto de mellora no dereito civil de Galicia

[Resumo] A nova Lei 2/2006, de 14 de xuño, de Dereito Civil de Galicia supón unha cambio transcendental nas institucións propias do dereito sucesorio galego. Dentro de elas, o pacto de mellora entre ascendentes e descendentes sobre bens concretos supón un sistema de delación hereditaria pero sobre todo, unha nova forma de transmisión a título gratuíto de presente dos bens aos fillos e descendentes sen esperar ao falecemento do ascendente, nin renuncia á condición de lexitimario como sucede na apartación e, por suposto, por título de pacto sucesorio e non de doazón, en termos todo iso alleos a todo o sistema sucesorio do Código Civil e dunha grande importancia económica e social.[Abstract] The new Law 2/2006, the 14th June on Galician Civil Law, involves a change of great importance in Galician succession law’s own institutions. Among them, the “beneficial improvement pact” among ancestors and descendants on concrete goods, leads to a system of hereditary denunciation but, mainly, to a new way of free transmission of the goods to children and other descendants without having to wait for the ancestor’s death or resigning to being the beneficiary of the “lexítima” (proportional share of the estate that passes by law to the family and dependants) as it would happen in the “apartación” (a heir gets goods from the estate before the death of the ascendant, but renounces to his condition of beneficiary of the “lexítima”) and, of course, by title of successive pact and not of donation, in terms of a great economic and social importance which are not known by the successive system of the Civil Code