Network Dynamics

Author(s):  
Peter Dodds ◽  
Duncan J. Watts

This article explores dynamic networks and diffusion, with particular emphasis on evolving traces of enacted social relations. It begins with a review of models for the evolution of networks over time — making a distinction between ‘node-based’ and ‘edge-based’ models — and more specifically how and why networks change. It then considers how network timing affects the flow of things across networks, focusing on how edge timing reshapes the set of paths potentially useful for diffusion. It also discusses the structure requirements for network diffusion and shows how these requirements are affected when we assume edges come and go over time. Finally, it describes the effect of tie order on diffusion potential as well as the correlation between network evolution and diffusion.

2015 ◽  
Vol 26 (04) ◽  
pp. 499-522 ◽  
Author(s):  
Arnaud Casteigts ◽  
Paola Flocchini ◽  
Bernard Mans ◽  
Nicola Santoro

Highly dynamic networks rarely offer end-to-end connectivity at a given time. Yet, connectivity in these networks can be established over time and space, based on temporal analogues of multi-hop paths (also called journeys). Attempting to optimize the selection of the journeys in these networks naturally leads to the study of three cases: shortest (minimum hop), fastest (minimum duration), and foremost (earliest arrival) journeys. Efficient centralized algorithms exists to compute all cases, when the full knowledge of the network evolution is given. In this paper, we study the distributed counterparts of these problems, i.e. shortest, fastest, and foremost broadcast with termination detection (TDB), with minimal knowledge on the topology. We show that the feasibility of each of these problems requires distinct features on the evolution, through identifying three classes of dynamic graphs wherein the problems become gradually feasible: graphs in which the re-appearance of edges is recurrent (class [Formula: see text]), bounded-recurrent ([Formula: see text]), or periodic ([Formula: see text]), together with specific knowledge that are respectively n (the number of nodes), Δ (a bound on the recurrence time), and p (the period). In these classes it is not required that all pairs of nodes get in contact — only that the overall footprint of the graph is connected over time. Our results, together with the strict inclusion between [Formula: see text], [Formula: see text], and [Formula: see text], implies a feasibility order among the three variants of the problem, i.e. TDB[foremost] requires weaker assumptions on the topology dynamics than TDB[shortest], which itself requires less than TDB[fastest]. Reversely, these differences in feasibility imply that the computational powers of [Formula: see text], [Formula: see text], and [Formula: see text] also form a strict hierarchy.


Author(s):  
Nikolay S. Savkin

Introduction. Radical pessimism and militant anti-natalism of Arthur Schopenhauer and David Benathar create an optimistic philosophy of life, according to which life is not meaningless. It is given by nature in a natural way, and a person lives, studies, works, makes a career, achieves results, grows, develops. Being an active subject of his own social relations, a person does not refuse to continue the race, no matter what difficulties, misfortunes and sufferings would be experienced. Benathar convinces that all life is continuous suffering, and existence is constant dying. Therefore, it is better not to be born. Materials and Methods. As the main theoretical and methodological direction of research, the dialectical materialist and integrative approaches are used, the realization of which, in conjunction with the synergetic technique, provides a certain result: is convinced that the idea of anti-natalism is inadequate, the idea of giving up life. A systematic approach and a comprehensive assessment of the studied processes provide for the disclosure of the contradictory nature of anti-natalism. Results of the study are presented in the form of conclusions that human life is naturally given by nature itself. Instincts, needs, interests embodied in a person, stimulate to active actions, and he lives. But even if we finish off with all of humanity by agreement, then over time, according to the laws of nature and according to evolutionary theory, man will inevitably, objectively, and naturally reappear. Discussion and Conclusion. The expected effect of the idea of inevitability of rebirth can be the formation of an optimistic orientation of a significant part of the youth, the idea of continuing life and building happiness, development. As a social being, man is universal, and the awareness of this universality allows one to understand one’s purpose – continuous versatile development.


X ◽  
2020 ◽  
Author(s):  
Marinella Arena ◽  
Paola Raffa

Defensive architecture in the Ziz and Todhra valleys in MoroccoThe earthen architecture of the Todhra and Ziz Valleys in Southern Morocco takes us back to the basic and archetypal forms of building in the Mediterranean. Architectural typology and language together form a cultural background that is strongly rooted in the territory and its inhabitants: the Berbers. The architectures, fragile and in constant decay, represent a treatise of living architecture in which the shapes, proportions and decorations are repeated over time with continuity.This research tries to verify, with data coming from direct and instrumental surveys, the quality and diffusion of the architectures that dot the valleys of the Todhra and the Ziz which, at same time, host the population and defend the most precious asset: water.  Along the valleys, united by the same language, we find: igherm, fortified citadels; tighremt, fortress houses.


Author(s):  
J. R. Ortt

This chapter focuses on the pre-diffusion phases for high-tech products. These phases last from the first time a technology is mastered and demonstrated up to the start of the large-scale production and diffusion of products based on that technology. The purpose of this chapter is to underline the managerial relevance of the pre-diffusion phases. Two questions will be answered in particular: (1) How long do these pre-diffusion phases last for high-tech products? (2) Have these phases shortened or not over the last 150 years? Fifty-three cases of high-tech products, invented between 1837 and 1998, are investigated. The pre-diffusion phases are shown to last 16 years on average, but their length varies considerably per case. No proof for the shortening of these phases over time is found. The resources devoted to research and development in different fields of expertise may have increased but the length of the pre-diffusion phases has not shortened accordingly.


Author(s):  
Purnendu Karmakar ◽  
Rajarshi Roy

Distributed network researchers are trying to address one important issue concerning networked structures and how the network came into existence, i.e., dynamics of network evolution. From the knowledge of social science it is observed that trust is one such metric that evolves with the network particularly where human interaction is involved. This work presents a “trust” model of the authors’ studies and its various properties. In virtual (and “real”) communities (chat rooms, blogs, etc.) behavioral segregation over time is observed. Differences in identities of interacting agents result in evolution of various degrees of “trust” (and “distrust’) among them over a period of time. This process ultimately leads to emergence of self-segregation in behavioral kinetics and results in formation of preference clusters.


Land ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 227
Author(s):  
Menelisi Falayi ◽  
James Gambiza ◽  
Michael Schoon

The loss of ecosystem services through land degradation continues to be a significant concern for policymakers and land users around the world. Facilitating collective action among various actors is regarded as imperative in halting land degradation. Despite extensive research on collective action, there have been few studies that continuously map social ties and detect network evolution as a way of enabling longitudinal analysis of transformative spaces. This paper seeks to examine the changing dynamics of multi-actor and multi-level actor ties over a period of two years in Machubeni, South Africa. To do this, we used social network analysis to detect continuities and/or discontinuities of multi-actor and multi-level actor ties over time. Overall, edge density, clustering coefficient, and reciprocity scores steadily increased over the two years despite a decline in the number of active organisations within the network. Our results demonstrate that the proportion of strong ties gradually increased over time across three governance networks. However, multi-level linkages between the local municipality and the local organisations remained weak due to a lack of trust and collaborative fatigue. While the transformative space has succeeded in enhancing collaboration and knowledge sharing between local organisations and researchers, further long-term engagement with government agencies might be necessary for promoting institutional transformations and policy outcomes, and building network resilience in complex polycentric governance systems.


Author(s):  
Peter Grindrod ◽  
Desmond J. Higham

To gain insights about dynamic networks, the dominant paradigm is to study discrete snapshots , or timeslices , as the interactions evolve. Here, we develop and test a new mathematical framework where network evolution is handled over continuous time, giving an elegant dynamical systems representation for the important concept of node centrality. The resulting system allows us to track the relative influence of each individual. This new setting is natural in many digital applications, offering both conceptual and computational advantages. The novel differential equations approach is convenient for modelling and analysis of network evolution and gives rise to an interesting application of the matrix logarithm function. From a computational perspective, it avoids the awkward up-front compromises between accuracy, efficiency and redundancy required in the prevalent discrete-time setting. Instead, we can rely on state-of-the-art ODE software, where discretization takes place adaptively in response to the prevailing system dynamics. The new centrality system generalizes the widely used Katz measure, and allows us to identify and track, at any resolution, the most influential nodes in terms of broadcasting and receiving information through time-dependent links. In addition to the classical static network notion of attenuation across edges, the new ODE also allows for attenuation over time, as information becomes stale. This allows ‘running measures’ to be computed, so that networks can be monitored in real time over arbitrarily long intervals. With regard to computational efficiency, we explain why it is cheaper to track good receivers of information than good broadcasters. An important consequence is that the overall broadcast activity in the network can also be monitored efficiently. We use two synthetic examples to validate the relevance of the new measures. We then illustrate the ideas on a large-scale voice call network, where key features are discovered that are not evident from snapshots or aggregates.


2017 ◽  
Vol 19 (1) ◽  
pp. 25-51 ◽  
Author(s):  
Narisong Huhe ◽  
Daniel Naurin ◽  
Robert Thomson

We test two of the main explanations of the formation of political ties. The first states that political actors are more likely to form a relationship if they have similar policy preferences. The second explanation, from network theory, predicts that the likelihood of a tie between two actors depends on the presence of certain relationships with other actors. Our data consist of a unique combination of actors' policy positions and their network relations over time in the Council of the European Union. We find evidence that both types of explanations matter, although there seems to be variation in the extent to which preference similarity affects network evolution. We consider the implications of these findings for understanding the decision-making in the Council.


2020 ◽  
Vol 7 (2) ◽  
pp. 191-206
Author(s):  
Arthi Shankar Kozhumam ◽  
Riti Chandrashekhar ◽  
Ananya Rattani ◽  
Sumedha Gupta Ariely

This study describes evidence for multiple attachments by orphaned and separated children (OSC) to caregivers and explores predictive relationships between attachment and family social relationships. A sample of forty-three longitudinal children residing in residential care between 15 and 144 months at the time of assessment and forty-two newer-to-care children (entering one to thirteen months before testing) was interviewed in summer 2019. Caregiver attachment was measured using the IPPA Guardian scale, and family social relations were measured using the PROMIS Pediatric Family Relationships scale. Longitudinal children displayed similar attachment scores across a one-year time span regardless of whether they nominated the same or different favourite caretaker. Results are discussed in the context of evidence for multiple attachments and the way attachment can predict social relations for new but not longitudinal children. This paper supports that OSCs form multiple attachments to caregivers over time, with attachment starting and remaining relatively strong in the long-term.


Sign in / Sign up

Export Citation Format

Share Document