Social Network Analysis as a Tool for Understanding the Diffusion of GIS Innovations: The Greek GIS Community

10.1068/b2667 ◽  
2000 ◽  
Vol 27 (4) ◽  
pp. 627-640 ◽  
Author(s):  
Dimitris G Assimakopoulos

In this paper I will show how social network analysis techniques can be used for understanding GIS diffusion at a national scale. In particular, two network models, cohesion and structural equivalence, are explored in the context of the emerging Greek GIS community. A map of this community based on GIS teams and linkages is put forward, and two social constructs, institutional setting and disciplinary background, are used to highlight the heterogeneous context within which GIS are embedded across a whole country. The findings suggest that specific actors such as the Greek ESRI vendor and relevant social groups such as the teams with a surveying engineering background take centre stage in the diffusion of GIS innovations in Greece in the early 1990s.

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yi-Chun Chang ◽  
Kuan-Ting Lai ◽  
Seng-Cho T. Chou ◽  
Wei-Chuan Chiang ◽  
Yuan-Chen Lin

PurposeTelecommunication (telecom) fraud is one of the most common crimes and causes the greatest financial losses. To effectively eradicate fraud groups, the key fraudsters must be identified and captured. One strategy is to analyze the fraud interaction network using social network analysis. However, the underlying structures of fraud networks are different from those of common social networks, which makes traditional indicators such as centrality not directly applicable. Recently, a new line of research called deep random walk has emerged. These methods utilize random walks to explore local information and then apply deep learning algorithms to learn the representative feature vectors. Although effective for many types of networks, random walk is used for discovering local structural equivalence and does not consider the global properties of nodes.Design/methodology/approachThe authors proposed a new method to combine the merits of deep random walk and social network analysis, which is called centrality-guided deep random walk. By using the centrality of nodes as edge weights, the authors’ biased random walks implicitly consider the global importance of nodes and can thus find key fraudster roles more accurately. To evaluate the authors’ algorithm, a real telecom fraud data set with around 562 fraudsters was built, which is the largest telecom fraud network to date.FindingsThe authors’ proposed method achieved better results than traditional centrality indices and various deep random walk algorithms and successfully identified key roles in a fraud network.Research limitations/implicationsThe study used co-offending and flight record to construct a criminal network, more interpersonal relationships of fraudsters, such as friendships and relatives, can be included in the future.Originality/valueThis paper proposed a novel algorithm, centrality-guided deep random walk, and applied it to a new telecom fraud data set. Experimental results show that the authors’ method can successfully identify the key roles in a fraud group and outperform other baseline methods. To the best of the authors’ knowledge, it is the largest analysis of telecom fraud network to date.


2016 ◽  
Vol 9 (2) ◽  
pp. 218-241 ◽  
Author(s):  
Johann-Mattis List (游函)

The evidence one can draw from the rhyming behavior of Old Chinese words plays a crucial role for the reconstruction of Old Chinese, and is particularly relevant to recent proposals. Some of these proposals are no longer solely based on the intuition of scholars but also substantiated by statistical arguments that help to assess the probability by which a given set of rhyming instances can be assigned to an established rhyme group. So far, however, quantitative methods were only used to confirm given hypotheses regarding rhyme groups in Old Chinese, and no exploratory analyses that would create hypotheses regarding rhyme groups in a corpus were carried out. This paper presents a new method that models rhyme data as weighted undirected networks. By representing rhyme words as nodes in a network and the frequency of rhymes in a given corpus as links between nodes, rhyme groups can be inferred with help of standard algorithms originally designed for social network analysis. This is illustrated through the construction of a rhyme network from the Book of Odes and comparing the automatically inferred rhyme groups with rhyme groups proposed in the literature. Apart from revealing interesting general properties of rhyme networks in Chinese historical phonology, the analysis provides strong evidence for a coda *-r in Old Chinese. The results of the analysis and the rhyme network of the Book of Odes can be inspected in form of an interactive online application or directly downloaded. 古代漢語的詞語所反映的韻為對上古音系的構擬,特別是對於最近的一些上古漢語構擬系統,異常重要。其中有一些構擬系統不再僅僅靠於學者的直覺,而且還用統計參數證實來評估分韻和派韻的概率。然而,迄今為止,定量方法僅用於確認關於上古韻部的假設,並且沒有進行探索性數據分析來創建初步分韻假設。本文提出了一種將韻母數據模型為加權無向網絡的新方法。此方法將韻母模型為網絡中的頂點,將某個語料庫的合韻率模型為聯頂點的邊緣,用社會網絡分析的標準算法來推斷語料庫所反映的韻母。為了更具體的說明此方法,本文用“詩經”來構建韻母網絡,而且比較自動與學者所推斷的上古韻部。除了揭示古代漢語韻網的一些有趣特點,“詩經”韻網分析了支持上古漢語韻尾* -r的新證據。“詩經”韻網和韻網分析的結果可以用交際在線應用來訪問而下載。(This article is in English.)


2014 ◽  
Vol 2 (2) ◽  
pp. 189-212 ◽  
Author(s):  
PER BLOCK ◽  
THOMAS GRUND

AbstractHomophily—the tendency for individuals to associate with similar others—is one of the most persistent findings in social network analysis. Its importance is established along the lines of a multitude of sociologically relevant dimensions, e.g. sex, ethnicity and social class. Existing research, however, mostly focuses on one dimension at a time. But people are inherently multidimensional, have many attributes and are members of multiple groups. In this article, we explore such multidimensionality further in the context of network dynamics. Are friendship ties increasingly likely to emerge and persist when individuals have an increasing number of attributes in common? We analyze eleven friendship networks of adolescents, draw on stochastic actor-oriented network models and focus on the interaction of established homophily effects. Our results indicate that main effects for homophily on various dimensions are positive. At the same time, the interaction of these homophily effects is negative. There seems to be a diminishing effect for having more than one attribute in common. We conclude that studies of homophily and friendship formation need to address such multidimensionality further.


Complexity ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Daniel A. Eisenberg ◽  
Jeryang Park ◽  
Thomas P. Seager

International efforts to improve power grid resilience mostly focus on technological solutions to reduce the probability of losses by designing hardened, automated, redundant, and smart systems. However, how well a system recovers from failures depends on policies and protocols for human and organizational coordination that must be considered alongside technological analyses. In this work, we develop a sociotechnical network analysis that considers technological and human systems together to support improved blackout response. We construct corresponding infrastructure and social network models for the Korean power grid and analyze them with betweenness to identify critical infrastructures and emergency management organizations. Power grid network analysis reveals important power companies and emergency management headquarters for responding to infrastructure losses, where social network analysis reveals how information-sharing and decision-making authority shifts among these organizations. We find that separate analyses provide relevant yet incomplete recommendations for improving blackout management protocols. In contrast, combined results recommend explicit ways to improve response by connecting key owner, operator, and emergency management organizations with the Ministry of Trade, Industry, and Energy. Findings demonstrate that both technological and social analyses provide important information for power grid resilience, and their combination is necessary to avoid unintended consequences for future blackout events.


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