Modelling a dynamic market potential: A class of automata networks for diffusion of innovations

Innovation diffusion processes are generally described at aggregate level with models like the Bass Model (BM) and the Generalized Bass Model (GBM). However, the recognized importance of communication channels between agents has recently suggested the use of agent-based models, like Cellular Automata. We argue that an adoption or purchase process is nested in a communication network that evolves dynamically and indirectly generates a latent non-constant market potential affecting the adoption phase.Using Cellular Automata we propose a two-stage model of an innovation diffusion process. First we describe a communication network, an Automata Network, necessary for the “awareness” of an innovation. Then, we model a nested process depicting the proper purchase dynamics. Through a mean field approximation we propose a continuous representation of the discrete time equations derived by our nested two-stage model. This constitutes a special non-autonomous Riccati equation, not yet described in well-known international catalogues. The main results refer to the closed form solution that includes a general dynamic market potential and to the corresponding statistical analysis for identification and inference. We discuss an application to the diffusion of a new pharmaceutical drug.     

Market discipline in the Brazilian banking industry: an analysis for the subordinated debt holders

Market discipline is a regulatory mechanism which has as its main task the punishment of bad risk management by financial institutions. Subordinated debt holders are considered by the literature as the most propitious private agent to discipline the financial institutions. The key to prove the existence of market discipline is to show the relationship between banks’ asset prices and its respective risks. The main objective of this article is an empirical analysis of the relation between credit risk (ratings and accounting information) and debentures return for the Brazilian case. The results denote a weak presence of market discipline in Brazil.     

Performance of private higher education institutions in Vietnam: evidence using DEA-based bootstrap directional distance approach with quasi-fixed inputs

Vietnam’s higher education has witnessed substantial improvements since the implementation of the Doi Moi (renovation) policy. One of the significant developments is the promotion of establishment and enhancement of the role of private institutions in national education systems. However, the quest to improve the overall performance of the private higher education institutions remains a big challenge for many stakeholders. We assess the performance of Vietnamese private universities using a data envelopment analysis–based bootstrap directional distance approach with quasi-fixed inputs. The results show that there was a large variation in the efficiency levels of private universities within and between academic years and between metropolitan and other private universities. Our empirical findings provide more insights for educational leaders and policy makers on the performance of private higher education institutions and the implications of privatization of the national higher education system.     

THREE HYPOTHESES ON THE BRAZILIAN SERVICE SECTOR

Three hypotheses on services, the Gershuny effect, the externalisation of producers services and the macroeconomic equation for the services share in employment, are tested with Brazilian data. The first two show trends similar to those in the developed economies, but, in the last one, findings are affected by consideration of the underground economy. The results suggest a dual character for Brazilian services: an informal, labour intensive group of sectors, present in the large metropolitan areas, coexists with a formal, less labour intensive one, where producers' services are probably predominant. These groups will respond differently to a greater trade liberalisation.     

IMP studies: A bridge between tradition and innovation

“Combining the Social and Technological Aspects of Innovation: Relationships and Networks” was the title of the 28th IMP Conference held in Rome, at Università Cattolica del Sacro Cuore in 2012.     

Negative network effects and asymmetric pure price equilibria

Portuguese Economic Journal - We show that in finite settings with identical firms and consumers, asymmetric pure price equilibria with positive profits exist. We consider a price competition...