21 research outputs found
Instability and network effects in innovative markets
No full textWe consider a network of interacting agents and we model the process of choice on the adoption of a given innovative product by means of statistical-mechanics tools. The modelization allows us to focus on the effects of direct interactions among agents in establishing the success or failure of the product itself. Mimicking real systems, the whole population is divided into two sub-communities called, respectively, Innovators and Followers, where the former are assumed to display more influence power. We study in detail and via numerical simulations on a random graph two different scenarios: no-feedback interaction, where innovators are cohesive and not sensitively affected by the remaining population, and feedback interaction, where the influence of followers on innovators is non negligible. The outcomes are markedly different: in the former case, which corresponds to the creation of a niche in the market, Innovators are able to drive and polarize the whole market. In the latter case the behavior of the market cannot be definitely predicted and become unstable. In both cases we highlight the emergence of collective phenomena and we show how the final outcome, in terms of the number of buyers, is affected by the concentration of innovators and by the interaction strengths among agents
A two-populations Ising model on diluted random graphs
No full textWe consider the Ising model for two interacting groups of spins embedded in an Erdös–Rényi random graph. The critical properties of the system are investigated by means of extensive Monte Carlo simulations. Our results evidence the existence of a phase transition at a value of the inter-groups interaction coupling J12C which depends algebraically on the dilution of the graph and on the relative width of the two populations, as explained by means of scaling arguments. We also measure the critical exponents, which are consistent with those of the Curie–Weiss model, hence suggesting a wide robustness of the universality class
The relation between global migration and trade networks
No full textIn this paper we develop a methodology to analyze and compare multiple global networks, focusing our analysis on the relation between human migration and trade. First, we identify the subset of products for which the presence of a community of migrants significantly increases trade intensity, where to assure comparability across networks we apply a hypergeometric filter that lets us identify those links which intensity is significantly higher than expected. Next, proposing a new way to define country neighbors based on the most intense links in the trade network, we use spatial econometrics techniques to measure the effect of migration on international trade, while controlling for network interdependences. Overall, we find that migration significantly boosts trade across countries and we are able to identify product categories for which this effect is particularly strong
The Indirect Effects of FDI on Trade: A Network Perspective
No full textThe relationship between international trade and foreign direct invest-
ment (FDI) is one of the main features of globalization. In this paper
we investigate the effects of FDI on trade from a network perspective,
since FDI takes not only direct but also indirect channels from origin to
destination countries because of firms' incentive to reduce tax burden,
to minimize coordination costs, and to break barriers to market entry.
We use a unique data set of international corporate control as a measure
of stock FDI to construct a corporate control network (CCN) where the
nodes are the countries and the edges are the corporate control relation-
ships. Based on the CCN, the network measures, i.e., the shortest path
length and the communicability, are computed to capture the indirect
channel of FDI. Empirically we find that corporate control has a positive
effect on trade both directly and indirectly. The result is robust with dif-
ferent specifications and estimation strategies. Hence, our paper provides
strong empirical evidence of the indirect effects of FDI on trade. More-
over, we identify a number of interplaying factors such as regional trade
agreements and the region of Asia. We also find that the indirect effects
are more pronounced for manufacturing sectors than for primary sectors
such as oil extraction and agriculture
The Relation Between Global Migration and Trade Networks
No full textIn this paper we develop a methodology to analyze and compare multiple global networks. We focus our analysis on the relation between human migration and trade. First, we identify the subset of products for which the presence of a community of migrants significantly increases trade intensity. To assure comparability across networks, we apply a hypergeometric filter to identify links for which migration and trade intensity are both significantly
higher than expected. Next we develop an econometric methodology, inspired by spatial econometrics, to measure the effect of migration on international trade while controlling for network interdependencies. Overall,
we find that migration significantly boosts trade across sectors and we are able to identify product categories for
which this effect is particularly strong
Attività della Commissione DDC-SCI/AIF: studio di fattibilità di un curriculum coordinato e/o integrato di chimica e di fisica per il biennio della scuola secondaria superiore
No full textUna proposta per l'insegnamento integrato della fisica e della chimica nel biennio della scuola secondaria superiore riformata
No full textCaratteristiche del progetto di un corso coordinato di chimica e di fisica per il biennio della scuola secondaria superiore
No full textIl ruolo del laboratorio in un curriculum di chimica e fisica per il biennio della scuola secondaria superiore
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