An elitism-based multi-objective evolutionary algorithm for min-cost network disintegration

Network disintegration or strengthening is a significant problem, which is widely used in infrastructure construction, social networks, infectious disease prevention and so on. But most studies assume that the cost of attacking anyone node is equal. In this paper, we investigate the robustness of complex networks under a more realistic assumption that costs are functions of degrees of nodes. A multi-objective, elitism-based, evolutionary algorithm (MOEEA) is proposed for the network disintegration problem with heterogeneous costs. By defining a new unit cost influence measure of the target attack node and combining with an elitism strategy, some combination nodes’ information can be retained. Through an ingenious update mechanism, this information is passed on to the next generation to guide the population to move to more promising regions, which can improve the rate of convergence of the proposed algorithm. A series of experiments have been carried out on four benchmark networks and some model networks, the results show that our method performs better than five other state-of-the-art attack strategies. MOEEA can usually find min-cost network disintegration solutions. Simultaneously, through testing different cost functions, we find that the stronger the cost heterogeneity, the better performance of our algorithm

Strategic perspectives on modularity

In this paper we argue that the debate on modularity has come to a point where a consensus is slowly emerging. However, we also contend that this consensus is clearly technology driven. In particular, no room is left for firm strategies. Typically, technology is considered as an exogenous variable to which firms have no choices but to adapt. Taking a slightly different perspective, our main objective is to offer a conceptual framework enabling to shed light on the role of corporate strategies in the process of modularization. From interviews with academic design engineers, we show that firms often consider product architecture as a critical variable to fit their strategic requirements. Based on design sciences, we build an original approach to product modularity. This approach, which leaves an important space for firms' strategic choices, proves also to seize a large part of the industrial reality of modularity. Our framework, which is a first step towards the consideration of strategies within the framework of modularity, gives an account for the diversity of industrial logics related to product modularization.product modularity ; corporate strategy ; technological determinism

The Dynamics of the Organisation of Industry

The paper presents and formalises an approach to the evolution of the organisation of industry which starts from multi-activity firms, and which relates to economists like Young, Stigler, and Richardson. To capture the open-ended process of disintegration of industry, the paper operates with decomposable tasks and gives an account of the vertical and horizontal structure of production by means of weighted trees — in the graphtheoretical sense. Based on this addition to the analytical toolbox, the paper gives an account of the decomposition of industry as driven by the structural innovations and process innovations of firms that specialise and exchange in an open-ended evolutionary process.Vertical disintegration, horizontal disintegration, production trees, specialisation of production, specialisation of R&D, George B. Richardson

Vertical Integration and Market Structure

Contractual theories of vertical integration derive firm boundaries as an efficient response to market transaction costs. These theories predict a relationship between underlying features of transactions and observed integration decisions. There has been some progress in testing these predictions, but less progress in quantifying their importance. One difficulty is that empirical applications often must consider firm structure together with industry structure. Research in industrial organization frequently has adopted this perspective, emphasizing how scale and scope economies, and strategic considerations, influence patterns of industry integration. But this research has paid less attention to contractual or organizational details, so that these two major lines of research on vertical integration have proceeded in parallel with only rare intersection. We discuss the value of combining different viewpoints from organizational economics and industrial organization.

Organisation of industry and innovation dynamics

The paper aims at investigating how the organization of a certain industry evolves once the competition among its firms, producing a ‘com-plex’ (i.e. non-modular) product, is modeled as the intertwining of innovative search and organizational change. In order to take the full roster of participants into account, and to retain the inner complexity of their decisions, a Pseudo–NK model is built–up in which a population of firms is called to match a technological frontier. By evolving along different stages of the sector’s life-cycle, such a kind of technological calls for a trade–off between two strategies of cost–reduction through either outsourcing or technological search. Overall, the simulation results confirm previous literature as, for example, in the introductory stage of the industry life–cycle, marked by frequent and intense jumps of the technological frontier, firms need to vertically integrate in order to have higher chances to win the competition for a new standard. On the contrary, in the decline stage, in which the technological frontier almost stabilizes, deverticalization allows firms to better compete on costs. These results change if suppliers are allowed to innovate, as they are more likely to lock the market in sub–optimal configurations

Coevolutionary games - a mini review

Prevalence of cooperation within groups of selfish individuals is puzzling in that it contradicts with the basic premise of natural selection. Favoring players with higher fitness, the latter is key for understanding the challenges faced by cooperators when competing with defectors. Evolutionary game theory provides a competent theoretical framework for addressing the subtleties of cooperation in such situations, which are known as social dilemmas. Recent advances point towards the fact that the evolution of strategies alone may be insufficient to fully exploit the benefits offered by cooperative behavior. Indeed, while spatial structure and heterogeneity, for example, have been recognized as potent promoters of cooperation, coevolutionary rules can extend the potentials of such entities further, and even more importantly, lead to the understanding of their emergence. The introduction of coevolutionary rules to evolutionary games implies, that besides the evolution of strategies, another property may simultaneously be subject to evolution as well. Coevolutionary rules may affect the interaction network, the reproduction capability of players, their reputation, mobility or age. Here we review recent works on evolutionary games incorporating coevolutionary rules, as well as give a didactic description of potential pitfalls and misconceptions associated with the subject. In addition, we briefly outline directions for future research that we feel are promising, thereby particularly focusing on dynamical effects of coevolutionary rules on the evolution of cooperation, which are still widely open to research and thus hold promise of exciting new discoveries.Comment: 24 two-column pages, 10 figures; accepted for publication in BioSystem