Murat Yildizoglu

Social and technological efficiency of patent systems

This article develops an evolutionary model of industry dynamics in order to carry out a richer theoretical analysis of the consequences of a stronger patent system. The first results obtained in our article are rather consistent with the anti-patent arguments and they do not favour the case for a stronger patent system: higher social welfare and technical progress are observed in our model in industries with milder patent systems (lower patent height and patent life).

LEARNING THE OPTIMAL BUFFER-STOCK CONSUMPTION RULE OF CARROLL

This article questions the rather pessimistic conclusions of Allen and Carroll (2001) about the ability of consumer to learn the optimal buer-stock based consumption rule. To this aim, we develop an agent based model where alternative learning schemes can be compared in terms of the consumption behaviour that they yield. We show that neither purely adaptive learning, nor social learning based on imitation can ensure satisfactory consumption behaviours. By contrast, if the agents can form adaptive expectations, based on an evolving individual mental model, their behaviour becomes much more interesting in terms of its regularity, and its ability to improve performance (which is as a clear manifestation of learning). Our results indicate that assumptions on bounded rationality, and on adaptive expectations are perfectly compatible with sound and realistic economic behaviour, which, in some cases, can even converge to the optimal solution. This framework may therefore be used to develop macroeconomic models with adaptive dynamics. JEL classification: E21, D91, D83, D84,

Organizational performance in hierarchies and communities of practice

Abstract In an earlier article we studied the Communities of Practice and their conditions of emergence using an Agent based model with a set of agents facing a continuous flow of problems. We now center our analysis on the performance of this organizational structure compared to a two-level hierarchical delegation structure. Our results show the crucial role played by the communication and the specialisation of agents; especially that community structures are efficient for competence building and learning in the long term. This paper backs the claim made by (Bowles, S., Gintis, H., 2002. Social capital and community governance. The Economic Journal 112, 419–437.) that hierarchy and communities are complementary modes of governance.

Modeling Adaptive Learning: R&D Strategies in the Model of Nelson & Winter (1982)

This article aims to test the relevance of learning through Genetic Algorithms (GA) and Learning Classifier Systems (LCS), in opposition with fixed R&D rules, in a simplified version of the evolutionary industry model of Nelson and Winter. These three R&D strategies are compared from the points of view of industry performance (welfare): the results of simulations clearly show that learning is a source of technological and social efficiency.

Efficiency of Network Structures: The Needle in the Haystack

The modelling of networks formation has recently became the object of an increasing interest in economics. One of the important issues raised in this literature is the one of networks efficiency. Nevertheless, for non trivial payoff functions, searching for efficient network structures turns out to be a very difficult analytical problem as well as a huge computational task, even for a relatively small number of agents. In this paper, we explore the possibility of using genetic algorithms (GA) techniques for identifying efficient network structures, because the GA have proved their power as a tool for solving complex optimization problems. The robustness of this method in predicting optimal network structures is tested on two simple stylized models introduced by Jackson and Wolinski (1996), for which the efficient networks are known over the whole state space of parameter values.

An Evolutionary Interpretation of the Aghion & Howitt (1992) Model

We test the robustness of the main growth mechanisms of the original Aghion & Howitt model by relaxing two central assumptions: the homogeneity of the agents and perfect foresight. To this end, we introduce boundedly rational firms in the R&D sector that are capable of learning. Our first results show that the original AH assumptions are essential for continuous endogenous growth of the economy. (This abstract was borrowed from another version of this item.) (This abstract was borrowed from another version of this item.) (This abstract was borrowed from another version of this item.) (This abstract was borrowed from another version of this item.) (This abstract was borrowed from another version of this item.) (This abstract was borrowed from another version of this item.) (This abstract was borrowed from another version of this item.) (This abstract was borrowed from another version of this item.) (This abstract was borrowed from another version of this item.) (This abstract was borrowed from another version of this item.) (This abstract was borrowed from another version of this item.) (This abstract was borrowed from another version of this item.) (This abstract was borrowed from another version of this item.) (This abstract was borrowed from another version of this item.) (This abstract was borrowed from another version of this item.) (This abstract was borrowed from another version of this item.) (This abstract was borrowed from another version of this item.) (This abstract was borrowed from another version of this item.) (This abstract was borrowed from another version of this item.) (This abstract was borrowed from (This abstract was borrowed from another version of this item.)