Density and Strength of Ties in Innovation Networks: An Analysis of Multi-Media and Biotechnology

In this article we provide an empirical illustration of hypotheses, developed in the literature, on the role of density and strength of ties in innovation networks.We study both exploration and exploitation networks in the Dutch multimedia and pharmaceutical biotechnology industry.We find support for most of our hypotheses but not all.These findings, in line with the mixed results in the literature, seem to indicate that the distinction between exploration versus exploitation, albeit useful, is still too general.There may be a stronger sectoral effect in how exploration and exploitation settle in network structural properties than anticipated thus far.innovation;networks;density;strength of ties;governance;biotechnology;multimedia

Evolutionary algorithm-based analysis of gravitational microlensing lightcurves

A new algorithm developed to perform autonomous fitting of gravitational microlensing lightcurves is presented. The new algorithm is conceptually simple, versatile and robust, and parallelises trivially; it combines features of extant evolutionary algorithms with some novel ones, and fares well on the problem of fitting binary-lens microlensing lightcurves, as well as on a number of other difficult optimisation problems. Success rates in excess of 90% are achieved when fitting synthetic though noisy binary-lens lightcurves, allowing no more than 20 minutes per fit on a desktop computer; this success rate is shown to compare very favourably with that of both a conventional (iterated simplex) algorithm, and a more state-of-the-art, artificial neural network-based approach. As such, this work provides proof of concept for the use of an evolutionary algorithm as the basis for real-time, autonomous modelling of microlensing events. Further work is required to investigate how the algorithm will fare when faced with more complex and realistic microlensing modelling problems; it is, however, argued here that the use of parallel computing platforms, such as inexpensive graphics processing units, should allow fitting times to be constrained to under an hour, even when dealing with complicated microlensing models. In any event, it is hoped that this work might stimulate some interest in evolutionary algorithms, and that the algorithm described here might prove useful for solving microlensing and/or more general model-fitting problems.Comment: 14 pages, 3 figures; accepted for publication in MNRA

Parallel ACO with a Ring Neighborhood for Dynamic TSP

The current paper introduces a new parallel computing technique based on ant colony optimization for a dynamic routing problem. In the dynamic traveling salesman problem the distances between cities as travel times are no longer fixed. The new technique uses a parallel model for a problem variant that allows a slight movement of nodes within their Neighborhoods. The algorithm is tested with success on several large data sets.Comment: 8 pages, 1 figure; accepted J. Information Technology Researc

Density And Strength Of Ties In Innovation Networks: A Competence And Governance View

This article studies density and strength of ties in innovation networks. It combines issues of ‘competence’ with issues of ‘governance’. It argues that in networks for exploration there are good reasons, counter to the thesis of the ‘strength of weak ties’, for a dense structure of ties that are strong in most dimensions. In exploitation, there are good reasons for structures that are non-dense, with ties that are strong in other dimensions than in networks for exploration. Evidence is presented from two longitudinal empirical studies of the emergence and development of networks in the multimedia and pharmaceutical biotechnology industries.governance;innovation;networks;biotechnology;multi-media;strength of ties

Density and strength of ties in innovation networks: a competence and governance view.

innovation, networks

Entrepreneurial Roles Along a Cycle of Discovery

The literature on entrepreneurship recognizes a variety of entrepreneurial roles, and the question arises what roles are played when and by whom.In this article, roles are attributed to different stages of innovation and organizational development.A central theme is the relation between discontinuity, in radical innovation (exploration), and continuity, in application, diffusion and adaptation (exploitation).Use is made of a concept of a 'cycle of discovery', which seeks to explain how exploration leads on to exploitation, and how exploitation may yield exploration, in a step-by-step development towards radical innovation.Parallel to this there are processes of organisational development.entrepreneurship;innovation;discovery;organizational learning