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NETWORKS
Nowadays, everybody talks about NETWORKS. Yet, what networks really are and how they function, often remains rather vague in conversations. LINKED: The new science of networks, a new book by Albert-Laszlo Barabási, offers great insight into the evolution, the structure and the relevance of networks. The author, Albert Barabási, himself a creative and important contributor to network science, makes the rapid and fascinating advances made in this field comprehensible.

THE STRUCTURE OF COMPLEX NETWORKS
Our world is filled with complex networks, webs of highly connected nodes. Not all nodes are equal, however. In fact, in many real-world complex networks, there is a typical hierarchy of nodes (called a POWERLAW DISTRIBUTION). This means there are a few extremely well connected nodes (these are called HUBS), there are quite a few moderately connected nodes and there are large numbers of tiny nodes (having very few connections to other nodes). The Internet, for instance, has only several hubs – like amazon.com and Yahoo – and countless tiny nodes -like my own website :-(.

GROWTH AND PREFERENTIAL ATTACHMENT
The structure of networks with a powerlaw distribution is called a SCALEFREE TOPOLOGY. Such a scale free topology is found in networks that 1) are GROWING (extra nodes and links emerge), and 2) are characterised by PREFERENTIAL ATTACHMENT (this means that some links are far more likely to get linked than others). Preferential attachment, is driven by two factors: 1) the number of links the node already has (this is in fact the first mover advantage: a node that has been there since the early development of the network gets the biggest chance to get connected), and 2) the node’s fitness (for instance a new website offering a truely unique service has an excellent chance to get many links).

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ROBUSTNESS AND VULNERABILITY
A fascinating characteristic of scale scale free networks is the following. The density of the interconnectivity paradoxically creates two properties at the same time: 1) ROBUSTNESS (removing nodes will not easily lead to the breakdown of the network, precisely because of the fact that all nodes are connected. Only simultaneous removal of the largest hubs will break down the network), and 2) VULNERABILITY TO ATTACK (because of the fact that all nodes are indirectely connected to each other failures, like viruses, can very easily spread through the whole network. This fenomenon is called ‘cascading failures’.

IMPLICATIONS FOR SCIENCE AND PRACTICE
Reading this book made me realise that the recently acquired knowledge about networks is revolutionizing many fields of science, like biology, medical science and economics. Also, the practical applications will be numerous, like protecting the internet, fighting terrorist networks, finding a cure for cancer (!), and developing new organizational forms.

Coert Visser. www.m-cc.nl

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A network consists of nodes which can be attached to other networks and form an internet. Without routers and gateways interoperability of different networks is impossible.
One can imagine that routers are the guys in an organization (network) who regulate communications between different part of an organization (different nodes). A router consists of both static and dynamic routing tables. The guy mentioned uses the static tables to decide where a specific report should go, while – for instance – in case of illness of a particular boss, he has to dynamically route specific data to a another node who knows what to do with it. Everything in communication is just a matter of routing data. One has to know where en how to communicate. An organization is a pool of nodes which communicate. The routers in an organizations are the guys that keep an organization together an manage the cooperation of different people doing operational work. On the lower levels there are subnets; every department in an organizations has his own network which has one router (the boss of the department) which communicates with higher level bosses. This guy loadbalances questions from the superboss by seperating tasks. The super super boss or top manager is the highes node in the network and this node routes data to other companies which use other protocols.
Suppose we can describe an organization like this, we can easily apply other networking related techniques to organizational problems and in my opinion that is the key to a lot of problems.
We can use VPNs (virtual private networks) to achieve more direct communication between different departments in other buildings or countries. We can even set up VPNs covering different organizations in the same branch! The only thing we have to do is tunneling data through the existing carriers.
It’s also possible to use firewalls to avoid quarrel between departments in an organization.
Maybe these are quite idealistic and practically impossible solutions, but using technological knowledge – which is almost always based on strict rules and therefore easy to understand – is a good starting point for finding solutions to organizational problems.

For those who want to know more, here are two interesting links about the book:

hyperlink Linked
hyperlink Albert-László Barabási

Coert Visser, http://www.m-cc.nl

For those who want to know more about hownetworking works in the real world I suggest the following books:

* “Open Systems Networking”,
D.Piscitello/A.Chapin
Addison-Wesley, 1993
* “TCP/IP Illustrated Volume 1 & 2”
R.Stevens,
Adison-Wesley, 1994

Both books cover the fundamentals of all network communication which make you can read this text. Using Stevens’ books you can even create your own applications.

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