Animating the development of Social Networks over time using a dynamic extension of multidimensional scaling

The animation of network visualizations poses technical and theoretical challenges. Rather stable patterns are required before the mental map enables a user to make inferences over time. In order to enhance stability, we developed an extension of stress-minimization with developments over time. This dynamic layouter is no longer based on linear interpolation between independent static visualizations, but change over time is used as a parameter in the optimization. Because of our focus on structural change versus stability the attention is shifted from the relational graph to the latent eigenvectors of matrices. The approach is illustrated with animations for the journal citation environments of Social Networks, the (co-)author networks in the carrying community of this journal, and the topical development using relations among its title words. Our results are also compared with animations based on PajekToSVGAnim and SoNIA

Nonlinear analysis of dynamical complex networks

Copyright © 2013 Zidong Wang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Complex networks are composed of a large number of highly interconnected dynamical units and therefore exhibit very complicated dynamics. Examples of such complex networks include the Internet, that is, a network of routers or domains, the World Wide Web (WWW), that is, a network of websites, the brain, that is, a network of neurons, and an organization, that is, a network of people. Since the introduction of the small-world network principle, a great deal of research has been focused on the dependence of the asymptotic behavior of interconnected oscillatory agents on the structural properties of complex networks. It has been found out that the general structure of the interaction network may play a crucial role in the emergence of synchronization phenomena in various fields such as physics, technology, and the life sciences

Collective behavior and evolutionary games - An introduction

This is an introduction to the special issue titled "Collective behavior and evolutionary games" that is in the making at Chaos, Solitons & Fractals. The term collective behavior covers many different phenomena in nature and society. From bird flocks and fish swarms to social movements and herding effects, it is the lack of a central planner that makes the spontaneous emergence of sometimes beautifully ordered and seemingly meticulously designed behavior all the more sensational and intriguing. The goal of the special issue is to attract submissions that identify unifying principles that describe the essential aspects of collective behavior, and which thus allow for a better interpretation and foster the understanding of the complexity arising in such systems. As the title of the special issue suggests, the later may come from the realm of evolutionary games, but this is certainly not a necessity, neither for this special issue, and certainly not in general. Interdisciplinary work on all aspects of collective behavior, regardless of background and motivation, and including synchronization and human cognition, is very welcome.Comment: 6 two-column pages, 1 figure; accepted for publication in Chaos, Solitons & Fractals [the special issue is available at http://www.sciencedirect.com/science/journal/09600779/56

Interdependent policy instrument preferences: a two-mode network approach

In policymaking, actors are likely to take the preferences of others into account when strategically positioning themselves. However, there is a lack of research that conceives of policy preferences as an interdependent system. In order to analyse interdependencies, we link actors to their policy preferences in water protection, which results in an actor-instrument network. As actors exhibit multiple preferences, a complex two-mode network between actors and policies emerges. We analyse whether actors exhibit interdependent preference profiles given shared policy objectives or social interactions among them. By fitting an exponential random graph model to the actor-instrument network, we find considerable clustering, meaning that actors tend to exhibit preferences for multiple policy instruments in common. Actors tend to exhibit interdependent policy preferences when they are interconnected, that is, they collaborate with each other. By contrast, actors are less likely to share policy preferences when a conflict line divides them

The clustering coefficient and community structure of bipartite networks

Many real-world networks display a natural bipartite structure. It is necessary and important to study the bipartite networks by using the bipartite structure of the data. Here we propose a modification of the clustering coefficient given by the fraction of cycles with size four in bipartite networks. Then we compare the two definitions in a special graph, and the results show that the modification one is better to character the network. Next we define a edge-clustering coefficient of bipartite networks to detect the community structure in original bipartite networks.Comment: 9 pages, 4 figure

Conceptual models of urban environmental information systems - toward improved information provision

Cities are the hub of European society - for over a millennium, they are the locus of social, political and economic development. As the core of intensive and creative human activity, they are also the place where the environmental externalities that accompany rapid development are most visible. The environmental consequences of urban development have been recognised long ago, as in the case of London, where in 1388 legislation was introduced to control pollutant emissions (Lowenthal, 1990). Similar historical environmental regulations can be demonstrated for many cities in Europe. However, while for most of history those who govern the city (be it the sovereign, city elders or local government) where responsible for the control, mitigation and management of the common environment in the city, the last 30 years are a period of profound change. This is due to the trend toward improved participation in environmental decision making . a more inclusive and open approach to decisions that deal with the city commons. This change did not occurre overnight but rather gradually. For example, in the United Kingdom, it was the Town and Country Planning Act of 1947 which introduced public scrutiny to changes in the urban form (Rydin, 1998), or the development of public involvement in environmental impact assessment of urban projects as developed in many countries throughout the developed world during the 1970s and 1980s (Gilpin 1995). These changes accelerate within the last three decades, and especially since the publication of .Our Common Future. (WCED and Brundtland 1987), the acceptance of the .Sustainable Development. principles and the Rio conference. A quiet (mini) revolution happened in Europe not long ago, toward the end of 1998 when the members of the United Nations Economic Commission for Europe (UN/ECE) signed the .Convention on Access to Information, Public Participation in Decision Making and Access to Justice in Environmental Matters. - the Aarhus Convention (UN/ECE 1998). The convention is expected to come into force by the end of 2001, and calls the governments and public authorities to open up access to environmental information as a means to improve public participation in environmental decision making and awareness of environmental issues (UN/ECE, 1998). However, these declarations on the value and importance of environmental information do not match our level of understanding on the role of environmental information in decision making processes, and especially on the role of information in improving awareness and participation. Therefore, it is useful to take a step back, and to try and evaluate how environmental information and access to it and its use support public involvement in such processes. This paper is aimed to offer a framework that can assist us in the analytical process of understanding environmental information use. It focuses on public access and assumes that environmental information will be delivered to the public through the Internet. Such assumption is based on the current trend within public authorities is to use Information and Communication Technology (ICT) as a major delivery medium and it seems that it will become more so in the near future (OECD 2000). The framework which this paper presents, is based on Soft Systems Methodology (SSM) study which unpacked some of the core issues relating to public access and use of environmental information (Haklay, 2001). Although the aim here is not to discuss the merits of SSM, but to focus on the conceptual models, some introduction to the techniques that are used here is needed. Therefore, the following section opens with introduction to SSM and its techniques. The core of the paper is dedicated to the development of conceptual models. After presenting the conceptual models, some conclusions about these models and their applications are drown

DIY networking as a facilitator for interdisciplinary research on the hybrid city

DIY networking is a technology with special characteristics compared to the public Internet, which holds a unique potential for empowering citizens to shape their hybrid urban space toward conviviality and collective awareness. It can also play the role of a “boundary object” for facilitating interdisciplinary interactions and participatory processes between different actors: researchers, engineers, practitioners, artists, designers, local authorities, and activists. This position paper presents a social learning framework, the DIY networking paradigm, that we aim to put in the centre of the hybrid space design process. We first introduce our individual views on the role of design as discussed in the fields of engineering, urban planning, urban interaction design, design research, and community informatics. We then introduce a simple methodology for combining these diverse perspectives into a meaningful interdisciplinary collaboration, through a series of related events with different structure and framing. We conclude with a short summary of a selection of these events, which serves also as an introduction to the CONTACT workshop on facilitating information sharing between strangers, in the context of the Hybrid City III conference

Robot swarming applications

This paper discusses the different modes of operation of a swarm of robots: (i) non-communicative swarming, (ii) communicative swarming, (iii) networking, (iv) olfactory-based navigation and (v) assistive swarming. I briefly present the state of the art in swarming and outline the major techniques applied for each mode of operation and discuss the related problems and expected results