eprintid: 634
rev_number: 18
eprint_status: archive
userid: 2
dir: disk0/00/00/06/34
datestamp: 2011-06-30 14:27:43
lastmod: 2014-12-18 15:28:35
status_changed: 2011-06-30 14:27:43
type: article
metadata_visibility: show
item_issues_count: 0
creators_name: Kitsak, Maksim
creators_name: Riccaboni, Massimo
creators_name: Havlin, Shlomo
creators_name: Pammolli, Fabio
creators_name: Stanley, H. Eugene
creators_id: 
creators_id: massimo.riccaboni@imtlucca.it
creators_id: 
creators_id: f.pammolli@imtlucca.it
creators_id: 
title: Scale-free models for the structure of business firm networks
ispublished: pub
subjects: HB
subjects: QC
divisions: EIC
full_text_status: public
keywords: PACS number(s): 89.75.Hc
note: © 2010 American Physical Society
abstract: We study firm collaborations in the life sciences and the information and communication technology sectors. We propose an approach to characterize industrial leadership using k-shell decomposition, with top-ranking firms in terms of market value in higher k-shell layers. We find that the life sciences industry network consists of three distinct components: a “nucleus,” which is a small well-connected subgraph, “tendrils,” which are small subgraphs consisting of small degree nodes connected exclusively to the nucleus, and a “bulk body,” which consists of the majority of nodes. Industrial leaders, i.e., the largest companies in terms of market value, are in the highest k-shells of both networks. The nucleus of the life sciences sector is very stable: once a firm enters the nucleus, it is likely to stay there for a long time. At the same time we do not observe the above three components in the information and communication technology sector. We also conduct a systematic study of these three components in random scale-free networks. Our results suggest that the sizes of the nucleus and the tendrils in scale-free networks decrease as the exponent of the power-law degree distribution λ increases, and disappear for λ≥3. We compare the k-shell structure of random scale-free model networks with two real-world business firm networks in the life sciences and in the information and communication technology sectors. We argue that the observed behavior of the k-shell structure in the two industries is consistent with the coexistence of both preferential and random agreements in the evolution of industrial networks.
date: 2010-03
date_type: published
publication: Physical Review E
volume: 81
number: 3
publisher: American Physical Society
pagerange: 036117
id_number: 10.1103/PhysRevE.81.036117
refereed: TRUE
issn: 1539-3755
official_url: http://link.aps.org/doi/10.1103/PhysRevE.81.036117
citation:   Kitsak, Maksim and Riccaboni, Massimo and Havlin, Shlomo and Pammolli, Fabio and Stanley, H. Eugene  Scale-free models for the structure of business firm networks.  Physical Review E, 81 (3).  036117.  ISSN 1539-3755      (2010)  
document_url: http://eprints.imtlucca.it/634/1/PhysRevE.Pammolli_Riccaboni_2010.pdf