Download presentation

Presentation is loading. Please wait.

Published byJeremiah Morrison Modified over 4 years ago

1
System-Biophysik Überblick Components Building Blocks Functional Modules System Lifes Complexity Pyramid (Oltvai-Barabasi, Science 10/25/02)

2
Zum Begriff Bio-System Input Out- put * Komponenten (Spezien) * Netzwerkartige Verknüpfungen (kinetische Raten) * Substrukturen (Knoten,Module, Motive) * Funktionelle Input => Output Relation * Erforschung der Bauprinzipen (reverse engineering) Vorsicht : Bauprinzip nicht rational sondern Ergebnis eines Evolutionprozesses * Erstellung quantitativer Modelle zur Beschreibung des Systems Eigenschaften Ziel

3
Boehring-Mennheim Large Metabolic Networks: the usual view

5
Network Measures

9
Network Types Random Scale-Free Hierarchical

10
Network Types Random Scale-Free Hierarchical

11
Network Types Random Scale-Free Hierarchical

12
Metabolic networks at different levels of description

13
Metabolic networks: Rather Hierarchical than Scale-free

15
Jeong et al Nature Oct 00 =2.2

16
Scale-free complex networks

17
Highly clustered small worlds Nature June 4, 1998Aug 1999 http://smallworld.sociology.columbia.edu

18
Finite size scaling: create a network with N nodes with P in (k) and P out (k) = 0.35 + 2.06 log(N) 19 degrees of separation: The WWW is very big but not very wide l 15 =2 [1,2,5] l 17 =4 [1,3,4,6,7] … = ?? 1 2 3 4 5 6 7 nd.edu 19 degrees of separation R. Albert et al Nature (99) based on 800 million webpages [S. Lawrence et al Nature (99)] A. Broder et al WWW9 (00) IBM 19 degrees

19
Nature July 27, 2000

20
Yeast protein interaction network red = lethal, green = non-lethal orange = slow growth yellow = unknown Topological robustness 10% proteins with k<5 are lethal BUT 60% proteins with k>15 are lethal

21
Construction of Scale-free networks These scale-free networks do not arise by chance alone. Erdős and Renyi (1960) studied a model of growth for graphs in which, at each step, two nodes are chosen uniformly at random and a link is inserted between them. The properties of these random graphs are not consistent with the properties observed in scale-free networks, and therefore a model for this growth process is needed. The scale-free properties of the Web have been studied, and its distribution of links is very close to a power law, because there are a few Web sites with huge numbers of links, which benefit from a good placement in search engines and an established presence on the Web. Those sites are the ones that attract more of the new links. This has been called the winners take all phenomenon. The mostly widely accepted generative model is Barabasi and Albert's (1999) rich get richer generative model in which each new Web page creates links to existent Web pages with a probability distribution which is not uniform, but proportional to the current in-degree of Web pages. This model was originally discovered by Derek de Solla Price in 1965 under the term cumulative advantage, but did not reach popularity until Barabasi rediscovered the results under its current name. According to this process, a page with many in-links will attract more in-links than a regular page. This generates a power-law but the resulting graph differs from the actual Web graph in other properties such as the presence of small tightly connected communities. More general models and networks characteristics have been proposed and studied (for a review see the book by Dorogovtsev and Mendes). A different generative model is the copy model studied by Kumar et al. (2000), in which new nodes choose an existent node at random and copy a fraction of the links of the existent node. This also generates a power law. However, if we look at communities of interests in a specific topic, discarding the major hubs of the Web, the distribution of links is no longer a power law but resembles more a normal distribution, as observed by Pennock et al. (2002) in the communities of the home pages of universities, public companies, newspapers and scientists. Based on these observations, the authors propose a generative model that mixes preferential attachment with a baseline probability of gaining a link. en.wikipedia.org

22
The origin of the scale-free topology and hubs in biological networks Evolutionary origin of scale-free networks

23
The origin of the scale-free topology and hubs in biological networks Evolutionary origin of scale-free networks

24
Beyond Networktopology Flux-Balance-Analysis

26
http://www.genome.jp/ligand/

27
Zusammenfassung Biologische Netzwerke Netzwerke haben eine hierachische Struktur - Komponenten, Blöcke, funktionelle Module, System Universelle Eigenschaften komplexer Netzwerke * small world property (kurze Verbindungswege) * skaleninvarianz (Verteilung der connectivity) * Starke Tendenz zu Clustern Große Zahl und inhomogene Komponenten Experimenteller Input durch: * Hochdurchsatztechniken / Datenbanken * Systematische Literaturanalyse (data-mining)

Similar presentations

OK

Algorithms and Computational Biology Lab, Department of Computer Science and & Information Engineering, National Taiwan University, Taiwan Network Biology.

Algorithms and Computational Biology Lab, Department of Computer Science and & Information Engineering, National Taiwan University, Taiwan Network Biology.

© 2018 SlidePlayer.com Inc.

All rights reserved.

To ensure the functioning of the site, we use **cookies**. We share information about your activities on the site with our partners and Google partners: social networks and companies engaged in advertising and web analytics. For more information, see the Privacy Policy and Google Privacy & Terms.
Your consent to our cookies if you continue to use this website.

Ads by Google

Convert free pdf to ppt online conversion Ppt on training need assessment and action research Ppt on peak load pricing strategy Ppt on direct and online marketing Ppt on bmc remedy change Ppt on sports awards in india Ppt on interest rate risk Ppt on merger and acquisition in india Ppt on earth movements and major landforms in mexico Ppt on bluetooth communication