LinkedThe 9th Link: Achilles’ Heel The 10th Link: Viruses and Fads

Amber Cornelius

Dawn Moore

Mark Strausser

The 9th Link: Achilles' Heel Easy to forget how dependent we are on modern technology Summer of 1996

Electricity totally down between the crest of the Rockies and the Pacific Coast

In financial terms, blackout was more devastating than the Great Northeast Blackout of 196530 million people without power for 13 hours

Today’s power grid is much more connected than the 1965 power grid

The 9th Link: Achilles' HeelPower grid used to be comprised of individual islands with only weak ties to rest of the grid

Blackouts caused people to panicResult of panics was that formerly islanded power systems began to link up

Gave rise to the largest man-made structure on Earth, containing enough wire to reach to the moon and back

The 9th Link: Achilles' Heel Huge electric grid was now so interconnected that a single disturbance could be detected thousands of miles away

1996 Blackout highlighted the vulnerability of system

Connectivity made power system more robust and efficient

However, errors could now cascade through entire system Connectivity caused vulnerability

The 9th Link: Achilles' HeelMan-made systems are corrupted by errors and failuresVehiclesComputer circuitry

Natural systems have a unique ability to survive in a wide range of conditions and errorsEcosystem

Between 3 and 100 million species go extinct per year, but causes little harm to overall system

The 9th Link: Achilles' HeelRobustness

Comes from Latin word meaning “oak” Signifies strength and longevity Symbolizes nature’s ability to maintain networks through interconnectivity

Increasingly investigated topic in many fields

Robustness is the ultimate goal for man-made networks and structuresCopying nature’s choice of a universal network structure

The 9th Link: Achilles' HeelIn 1999, Defense Advanced Research Projects Agency (DARPA) called for proposals to study fault-tolerant networks“the program will focus primarily on the development of new network technologies that will allow the networks of the future to be resistant to attacks and continue to provide network services”

The 9th Link: Achilles' HeelNode Failures

Can easily break a network into isolated islands

Such fragmentation is well-known property of networks affected by failures

How long will it take to break a network if we remove random nodes? Decades of research on random networks indicates that it is not a gradual process Removing a few nodes has little impact If critical number of nodes are removed, the system abruptly breaks

The 9th Link: Achilles' Heel In January 2000, the DARPA proposal motivated a series of computer experiments to test the Internet’s resilience to router failures Using an Internet map and computer simulation, started removing randomly selected nodes

Expected Internet to break apart when critical number of nodes reached

The Internet refused to break apart Removed as many as 80% of nodes, and remaining 20% formed a tightly interlinked cluster

The 9th Link: Achilles' Heel Realized that the Internet, unlike other human made structures, showed high degree of robustness Frequent and unavoidable breakdowns of routers rarely cause significant disruptions of service

Soon became clear that this robustness was not unique to the Internet

Any scale-free network can tolerate removal of random nodes and not break apart Internet World Wide Web Cell networks Social networks

The 9th Link: Achilles' HeelSource of amazing robustness in scale-free networks?Hub: highly connected nodes keep networks together

Failures, however, do not discriminate between nodesAffect large hubs and small nodes with same probability

Small nodes more likely to be affected, as they number many, many more than large hubs

The 9th Link: Achilles' HeelScale-free networks where the degree exponent is less than or equal to three have no critical thresholdMost networks of interest have a degree exponent less than three

These scale-free networks will only break apart when all nodes have been removed Or for all practical purposes, never

The 9th Link: Achilles' HeelSummer of 1997

National Security Agency (NSA) called for a war game to test the security of the US electronic infrastructure

Hired between 25 and 50 computer specialists to execute a coordinated attack on the nation’s unclassified systems Power grid 911 systems

The 9th Link: Achilles' Heel Operation Eligible Receiver

Illustrated that such assaults by moderately sophisticated adversaries were plausible and potentially devastatingCapable of toppling US military communication systems and other critical infrastructures completely

Demonstrated frightening vulnerabilities in US economic and security systems

Attacks intuitively aimed to decimate the hubs

The 9th Link: Achilles' Heel The author embarked on a new set of experiments that mimicked the actions of the attackers

Targeted the hubs of the network instead of randomly selecting nodes

Consequences were immediately evident Removal of one hub did not break system Removal of several hubs, disruptions were clearLarge chunks of nodes were falling off of the network

Removing even more hubs collapsed the network entirely

The 9th Link: Achilles' Heel The response of scale-free networks under attack is similar to that of random networks under failures Same collapse witnessed when:

removing highly connected proteins from a yeast cell

deleting highly connected nodes from food webs

Crucial difference is that it only takes disabling a few hubs for the scale-free network to collapse into tiny fragments

The 9th Link: Achilles' Heel DARPA refused Barabási’s paper detailing the error and attack tolerance of complex networks Nature featured it on their front cover

In 2000, no one could see foresee the important role that scale-free networks would play in our understanding of attack survivability and fault tolerance

The fact that the Internet was a scale-free network was only known to a few researchers Consequences were clearly unexplored

The 9th Link: Achilles' Heel Robustness of scale-free network comes at cost of fragility under attack

Although they are vulnerable to attack at their hubs, several of the largest hubs must be simultaneously removed to crush them Would require several hundred Internet routers to be attacked disabled at the same time

It might appear that the Internet’s topology harbors strong defenses against both random breakdowns and malicious assaults Unfortunately, this is not really the case

The 9th Link: Achilles' Heel 1996 blackout turned out to not be the result of an organized attack

Blackout was the result of a cascading failure A cascading failure is a failure in a system of interconnected parts in which the failure of a part can trigger the failure of successive parts

Local failure shifts load or responsibilities to other nodes If negligible load, can be absorbed If load is too much, node again shifts load or it fails

Magnitude and reach of failure depends on the centrality and capacity of nodes removed in the first round

The 9th Link: Achilles' Heel Cascading failures are not unique to power grids Internet

Routers do not break, they merely form a queue and drop packets if they can’t process them fast enough

End result is denial-of-service Removal of several large nodes could result in the same

catastrophic disruption on the Internet as the power line failing in the 1996 blackout caused

Economy 1997: International Monetary Fund puts pressure on

banks, banks call loans in from companies Led to a cascade of bank and corporation failures

Ecosystem Removal of a specific species can lead to a significant

reorganization of the ecosystem

The 9th Link: Achilles' Heel Duncan Watts, Columbia University

Discovered that most cascades are not instantaneous Failure can go unnoticed for a long time before starting a landslide

Cascading failures Understanding is limited They are a dynamic property of complex networks

Barabási expects that there are still undiscovered laws that govern how cascading failures work

Discovery of those laws would have profound implications for many fields, from the Internet to marketing

The 9th Link: Achilles' Heel Error tolerance we’ve discussed is good news Network robustness allows

Humans to recover from minor malfunctions and irritations

Internet router errors to not really be noticed The ecosystem to continue on even as species disappear

Price for this is extreme vulnerability to attacks All complex systems have their Achilles’ Heel With increased awareness and research, understanding of these issues will definitely improve over time

Tenth Link: Viruses and Fads Gaetan Dugas and the spread of AIDS

He was known as Patient Zero He is an example of the power of HUBS Mike Collins created a cartoon about the 200 Florida ballot and he sent it to 30 of his friends

The cartoon circled the globe and a business was born overnight

The Spread of Viruses and Fads Depends heavily on first adopters, also known as innovators Ipod Apple Newton Palm Pilots Hybrid Corn Seed

Early Adopters Early Majority Late Majority Lagards

How do Social Ties effect Behavior

1954 Elihu Katz circulated a proposal to study the effects of social ties on behavior

Fellow Columbia Alumni, was the director of Market Research at Pfizer

He offered Katz and his partners 40K dollars to track the spread of Tetracycline

Katz, Coleman, and Menzel Study

125 Doctors

3 DoctorsDiscussed Medical

Practices with.

3 Doctors thatThey sought advice

About a medicine

3 Doctors that They considered

To be Friends

Results

A few of the doctors were named by a large fraction of their colleagues as playing an important role in day to day decisions. These are known as the HUBS

The doctors who were named as friends were 3x’s more likely to adopt the new drug

Prescriptions were followed using the local pharmacies records

The early adopters and early majority had numerous social links

The trend would then spread to doctors who were not as connected

What is a HUB

Hubs are often referred to as Opinion Leaders Power Users Influencers

They are individuals who communicate with more people about a certain product than the average person

They are the first to notice and use the experience of the Innovators

If the hubs resist a product a wall will be formed and the product will likely fail

Apple Newton Fails, but the a market is born!

The First Mover does not always have the advantage

A number of poor reviews about the Newtons hand writing recognition application

Extremely poor battery lifeWhy did Newton Fail? (Advertising is not a sufficient Argument)

Threshold Model

We all differ in our willingness to accept innovation Diffusion Models assign a threshold to each individual, quantifying the likelihood that he or she will adopt a given innovation

All products have a Spreading Rate.(From introduction to purchase)

Crititical Threshold- A quantity determined by the properties of the network in which the innovation spreads

If the spreading rate is lower than the critical threshold, the product will die out. If it is higher, then eventually, every user who can, will adopt the innovation

Critical Threshold is part of every diffusion theory today

The Love Bug

The Love Bug was a computer virus which spread rapidly in May 2000

It originated in the Phillipines and was one of the most destructive computer viruses to date

The virus shut down financial systems in Belgium

The virus also crippled operations at Parliament

Eighty percent of computers belonging to the Federal government were infected

The Love Bug caused over ten billion dollars in damages

How the Love Bug Spread

An e-mail was sent to the unwitting user with a subject line that read “Love-Letter-For-You?”

A user would open the e-mail and the damage began

The Love Bug had an affinity for MP3 and JPEG files

The Love Bug used the Outlook e-mail client to send e-mails to contacts stored in the Outlook address book

The Love Bug is still around today despite having an antidote

A Closer Look at Viruses

Romualdo Pastor-Satorras and Alessandro Vespignani concluded that the life cycle of a virus is between six and fourteen months

The pair discovered that viruses were still infecting computers long after they had been “eradicated”

Conventional Wisdom States….If computers are randomly connected:A virulent (highly contagious) virus which passes the threshold will reach most computers

If the level of virulence is less than the threshold the number of new infections decline and the virus dies out eventually

Another Theory on the Spreading of Viruses• Computers are not connected randomlyScale free networks appear to not have any threshold

Viruses can have an indefinite life cycle

Even if a virus is not highly contagious it will still spread and enjoy a long life cycle

Computer Viruses and AIDS

Understanding how computer viruses are spread give us a good understanding how AIDS might be spread

The spread of AIDS follows a similar “Power Law” logic to Scale Free networks

Slowing the Spread of AIDS AIDS is difficult to treat largely due to cost

In places such as Africa even if the costs were reduced the lack of infrastructure would make it difficult to deliver medicines to all who needed them

One method is to treat the ‘hubs’ but that requires that hubs are known members of the population

Slowing the Spread of AIDSThe effectiveness of treating just ‘hubs’ has been questioned

The fairness of only treating those who where ‘sexually connected’ has been called into question

It is possible that many who needed treatment would not get it simply because they were not ‘hubs’

Random Events May Not Be So Random After AllRandom occurrences are a part of any major event

Major events can be predicted with a high degree of accuracy despite random occurrences

New booms can be predicted whether it is the AIDS virus or the Love Bug Virus

Conclusion

Technology has become such a part of our lives that we take the availability of it for granted.

Because our technologies are linked, a major failure in one area can cause failures in other areas in a cascading effect.

A failure can be mechanical, technological, biological, intentional, or unintentional.

Any mass failure of the technology we depend on will have expensive and broad reaching implications for an undefined period of time.

Questions?