Network theory

About: Network theory is a research topic. Over the lifetime, 2257 publications have been published within this topic receiving 109864 citations.

Network Theory and Systems

Abstract: This chapter focuses on network theory and systems. A network is a set of nodes whose interconnections represent transmission or energy flow. These nodes may be resistors, capacitors, or even nerve cells in the visual system—the interconnections being the axonal and dendritic tree structures. Because of the great developments in electrophysiology, most network models for neural function involve concepts of electronic components used in general electrical networks. This chapter presents network models for retinal, cortical, and eye-movement systems to explain the way in which specific network properties are representative of visual function. With the development of microelectrode recording techniques, it has become possible to record the electrical activity of cells within the visual system. An essential property of systems analyses is that they can quantitatively evaluate one model against others. This involves assumptions about signal samples and response populations that are the linearity and nonlinearity of the system, and the application of specific statistical decision models.

Identifying important nodes in scientific publications using co-authorship network

Abstract: The amounts of data are growing continuously. The data can make a benefit for the organization if they have the right plan to collect and analyze the data. In this paper, we examine data on research citation information. Many authors create interesting articles for propagating information to other researchers. The relationship network of researchers is also growing continuously. Learning network of researchers is necessary to find who has the most influence on others in the network. The researchers do not only have many papers but also they have co-authors who may stay in different communities. Adaptive information from various topics will make original papers. The combination of knowledge among researchers from various communities is a good way to create interesting papers. The aim of this article is to present a new measurement for author evaluation by using clustering coefficient and weighted degree centrality. The result will be used to rank researchers in order and analyze properties of the top 5 researchers. The ranking result can be comparable to the popular usage method, h-index. Hence, the new measurement for author evaluation using social network analysis measurement is a good way for author ranking.

A network analysis of the global energy market: an insight on the entanglement between crude oil and the world economy

Abstract: One major hurdle in the road toward a low carbon economy is the present entanglement of developed economies with oil. This tight relationship is mirrored in the correlation between most of economic indicators with oil price. This paper addresses the role of oil compared to the other three main energy commodities -coal, gas and electricity, in shaping the international trading network (ITW or WTW, world trade web) in the light of network theory. It initially surveys briefly the literature on the correlation between oil prices with economic growth and compares the concepts of time correlation with the concept of spatial correlation brought about by network theory. It outlines the conceptual framework underpinning the network measures adopted in the analysis and results are presented. Three measures are taken into account: the ratio of mutual exchanges in the network (reciprocity); the role of distances in determining trades (spatial filling); and the spatial correlation of energy commodities with the whole trade network and with four trading categories: food, capital goods, intermediate goods and consumption goods. The analysis deliver five main results:1) the the energy commodities network was structurally stable amid dramatic growth during the decade considered; 2) that oil is the most correlated energy commodity to the world trade web; 3) that oil is the most pervasive network, though coal is the less affected by distances; 4) that oil has a remarkably high level of internal reciprocity and external overlapping 5) that the reciprocity of the trade network is negative correlated in time with the price of oil.

Complexity in decision-making - the case of Maasvlakte - Connecting decisions, arenas and actors in spatial decision-making

Abstract: Decision-making about infrastructure is very complex. Decisions to develop the Rotterdam harbour are being taken in a network of local, regional and national actors and influenced by international actors (firms, NGOÂ’s etc.) both public and private. This decision-making process shows a lot of uncertainty and complexity and the outcomes are of great importance for the development of the harbour. Network theory has been widely used to indicate, explain and manage uncertainty in decision-making processes. The theory is well equipped for empirical research and has shown many applicable results. The attention for influences from outside the network to decision-making inside the network is however still poorly developed. In the case of decision-making with a strong international component this is a handicap. In this paper the relation between influences from outside and decision-making inside networks is studied both theoretically and empirically. A distinction is made between locally bound and non-locally bound networks to theorise the complex decision-making process. The well-known scientific concept of space of flows versus space of places from Manuel Castells is used as an inspiration to describe the relation between the locally and non-locally bounded networks of decision making. The locally bounded network is formed by the formal decision making process between the governmental and non-governmental organisations in countries, regions and municipalities. The non-locally bounded networks exist of organizations that are footloose and act globally mainly according to economic principals. The concept of inclusion is used to analyse the various actors in the decision-making process. The paper starts with the description of the external influences in port areas in general. The balance between the influence of local and non-local bounded networks depends on the multiple-inclusion of the different actors in the decision-making process in both networks. In areas in which many actors are included in the place-bounded networks, the external influences can be expected to be marginal. The port area of Rotterdam is a node in international networks and so the hypothesis can be set that in the Rotterdam port area the influence of actors mainly included in non-place bounded networks is significant in decision making networks. To explore this assumption various networks, which are relevant for decision-making about spatial issues in the Rotterdam port are identified and the differences in inclusion of the relevant actors is analysed. By means of the analysis of perceptions of the various actors (locally bound or non-locally bound) and their strategic choices and decisions we show that notions on international port development are being interpreted and transformed quite differently by the various actors. This first part of analysis highlights the possible gap between the awareness of the various actors of the non-locally bounded networks and their translation into their strategies in local bounded networks. We also trace difference of perceptions and strategies between actors who solely operate in locally bound networks and actors who are both included in locally and non-locally bound networks (like shipping firms etc). This second part of analysis indicates if there are differences in what the actors use as input for their respective positions in the decision-making networks. The paper shows that the influence of external developments in non-locally bound networks manifests itself in locally bound networks but is transformed and interpreted in many ways by the different actors. The paper ends with some conclusions about decision-making on large ports and the possibilities to influence this complex decision-making process that takes place in locally bound and non-locally bounded networks at the same time.

Principal centrality measures: a comprehensive approach to the Spanish stocks market

Abstract: In social network analysis, for determining the relevance or significance of a node in the network, several node centrality measures are often used such as degree centrality, betwenness centrality, closeness centrality, eigenvector, subgraph and page rank centrality. In this paper we apply a principal components analysis over the traditional centrality measures for obtaining an overall single metric that combines the best attributes of the traditional centrality measures and permits to detect relevant nodes in the network. Concretely, a detailed study of the Spanish stocks market will be used for demonstrating the advantages of this approach.