Complex World
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Complex World
Cutting Edge Research about Complex Systems
Curated by Claudia Mihai
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Focus on Swarming in Biological and Related Systems

Focus on Swarming in Biological and Related Systems | Complex World | Scoop.it

In the last 15 years, the collective motion of large numbers of self-propelled objects has become an increasingly active area of research. The examples of such collective motion abound: flocks of birds, schools of fish, swarms of insects, herds of animals etc. Swarming of living creatures is believed to be critical for the population survival under harsh conditions.

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Approaching the Limit of Predictability in Human Mobility

Approaching the Limit of Predictability in Human Mobility | Complex World | Scoop.it

Abstract excerpt: In this study we analyze the travel patterns of 500,000 individuals in Cote d'Ivoire using mobile phone call data records. 

Our findings indicate that human mobility is highly dependent on historical behaviors, and that the maximum predictability is not only a fundamental theoretical limit for potential predictive power, but also an approachable target for actual prediction accuracy.

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Community Structure and Multi-Modal Oscillations in Complex Networks

Community Structure and Multi-Modal Oscillations in Complex Networks | Complex World | Scoop.it

Abstract excerpt: In many types of network, the relationship between structure and function is of great significance. We are particularly interested in community structures, which arise in a wide variety of domains. We apply a simple oscillator model to networks with community structures and show that waves of regular oscillation are caused by synchronised clusters of nodes. Moreover, we show that such global oscillations may arise as a direct result of network topology.

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Twitter Datastream Used to Predict Flu Outbreaks

Twitter Datastream Used to Predict Flu Outbreaks | Complex World | Scoop.it
The rate at which people post flu-related tweets could become a powerful tool in the battle to spot epidemics earlier, say computer scientists.
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Default Cascades in Complex Networks: Topology and Systemic Risk

Default Cascades in Complex Networks: Topology and Systemic Risk | Complex World | Scoop.it
The recent crisis has brought to the fore a crucial question that remains still open: what would be the optimal architecture of financial systems?
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Network modularity reveals critical scales for connectivity in ecology and evolution

Network modularity reveals critical scales for connectivity in ecology and evolution | Complex World | Scoop.it

From Abstract: We argue that network modularity reveals critical meso-scales that are probably common in populations, providing a powerful means of identifying fundamental scales for biology and for conservation strategies aimed at recovering imperilled species.

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Quantum Google in a Complex Network

Quantum Google in a Complex Network | Complex World | Scoop.it

Abstract: We investigate the behaviour of the recently proposed Quantum PageRank algorithm, in large complex networks. We find that the algorithm is able to univocally reveal the underlying topology of the network and to identify and order the most relevant nodes. Furthermore, it is capable to clearly highlight the structure of secondary hubs and to resolve the degeneracy in importance of the low lying part of the list of rankings. The quantum algorithm displays an increased stability with respect to a variation of the damping parameter, present in the Google algorithm, and a more clearly pronounced power-law behaviour in the distribution of importance, as compared to the classical algorithm. We test the performance and confirm the listed features by applying it to real world examples from the WWW. Finally, we raise and partially address whether the increased sensitivity of the quantum algorithm persists under coordinated attacks in scale-free and random networks.

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luiy's curator insight, October 9, 2013 6:43 AM

In particular, two main fundamental questions will be addressed:

Does the quantum PageRank algorithm preserve the structure of a scale-free network? In other words, does the ranking distribution obtained by the quantum algorithm follow the same pattern of node-importance as the underlying scale-free network, and can it be clearly distinguished from the distribution corresponding to a random Erdős-Rényi network? Complementary, for Erdős-Rényi networks we study the characteristic behaviour of the quantum Page Rank algorithm applied to these random networks and contrast it with the results for scale-free networks.To which extent does the quantum Google algorithm provide an improvement on the information gained on some properties of scale-free networks, as compared to the classical PageRank algorithm?

 

Results.

 

We find that the algorithm clearly identifies that the networks are of scale-free type and is able to point out the most important hubs. This is a task already well performed by the classical PageRank. However, the quantum PageRank algorithm has improved ranking capabilities in the sense that is does not concentrate all the importance on these few nodes. Indeed, it is capable to unveil the structure of the graph in more detail as it also highlights the secondary hubs of the scale-free networks (see figures 2, 3, 4 and captions therein for examples, as well as the appendix for a statistical analysis of an ensemble of random graphs).

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It's all about data

It's all about data | Complex World | Scoop.it

Research data comes in various forms and levels of significance. Finding the best way to share all of the results of a research project can be difficult, but new ways are constantly emerging. Scientists disseminate their work by writing and publishing scientific papers, but this finished product can conceal a wealth of effort and information. Behind the text and figures is the data itself, which has been recorded, analysed, interpreted and, eventually, summarized in graphs and images. The process is necessary, but it can mean that accessing the underlying data is not straightforward.


Via Alin Velea
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Quantifying Long-Term Scientific Impact

Quantifying Long-Term Scientific Impact | Complex World | Scoop.it

Abstract: The lack of predictability of citation-based measures frequently used to gauge impact, from impact factors to short-term citations, raises a fundamental question: Is there long-term predictability in citation patterns? Here, we derive a mechanistic model for the citation dynamics of individual papers, allowing us to collapse the citation histories of papers from different journals and disciplines into a single curve, indicating that all papers tend to follow the same universal temporal pattern. The observed patterns not only help us uncover basic mechanisms that govern scientific impact but also offer reliable measures of influence that may have potential policy implications.

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Social group may be key to fostering creativity

Social group may be key to fostering creativity | Complex World | Scoop.it
(Phys.org) —Creativity and genius are commonly seen as attributes of an individual, but new research indicates the role played by the surrounding group may be just as important.
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How ants investigate the housing market when searching for their ideal home

How ants investigate the housing market when searching for their ideal home | Complex World | Scoop.it
An immediate and chronic concern for many of us is how the housing market influences the whole economy: surprisingly ants also have issues over the value of new homes, researchers from the University of Bristol have found.
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The Pigeonhole Principle

The Pigeonhole Principle | Complex World | Scoop.it

Certain facts in mathematics feel as though they contain a kind of compressed power—they look innocuous and mild-mannered when you first meet them, but they're dazzling when you see them in action. One of the most compelling examples of such a fact is the Pigeonhole Principle.

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Significant Scales in Community Structure

Significant Scales in Community Structure | Complex World | Scoop.it
Many complex networks show signs of modular structure, uncovered by community detection. Although many methods succeed in revealing various partitions, it remains difficult to detect at what scale some partition is significant.
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Eric L Berlow's curator insight, October 17, 2013 11:48 AM

Evaluating the statistical significance of modules within networks identified by community detection algorithms

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Can thermodynamics help us better understand human cancers?

Can thermodynamics help us better understand human cancers? | Complex World | Scoop.it

In a new study, UCLA researchers analyzed the gene-expression profiles of more than 2,000 patients and were able to identify cancer-specific gene signatures for breast, lung, prostate and ovarian cancers. The study applied an innovative approach to gene-array analysis known as "surprisal analysis," which uses the principles of thermodynamics—the study of the relationship between different forms of energy—to understand cellular processes in cancer.

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The Geography of Happiness: Connecting Twitter Sentiment and Expression, Demographics, and Objective Characteristics of Place

The Geography of Happiness: Connecting Twitter Sentiment and Expression, Demographics, and Objective Characteristics of Place | Complex World | Scoop.it

Abstract excerpt: We conduct a detailed investigation of correlations between real-time expressions of individuals made across the United States and a wide range of emotional, geographic, demographic, and health characteristics. Our results show how social media may potentially be used to estimate real-time levels and changes in population-scale measures such as obesity rates.

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Ali Anani's curator insight, November 9, 2013 6:11 AM

The heat map of happiness measured creatively

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Memory Is Inherently Fallible, And That's a Good Thing

Memory Is Inherently Fallible, And That's a Good Thing | Complex World | Scoop.it

For the previous century, the accepted view was that once captured and stored in neural circuits in the brain, a memory could be retrieved but could not be rewritten. In that view, every time an experience is relived, it is the same, over and over.

 Now, however, researchers understand that the process of recalling a memory actually changes it. “Each time you retrieve a memory it undergoes this storage process,”. That means the memory is in an unstable state, rewritten and remodeled every time it is retrieved.
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Griffiths phases and the stretching of criticality in brain networks

Griffiths phases and the stretching of criticality in brain networks | Complex World | Scoop.it

From Abstract: Hallmarks of criticality, such as power-laws and scale invariance, have been empirically found in cortical-network dynamics and it has been conjectured that operating at criticality entails functional advantages, such as optimal computational capabilities, memory and large dynamical ranges. As critical behaviour requires a high degree of fine tuning to emerge, some type of self-tuning mechanism needs to be invoked. Here we show that, taking into account the complex hierarchical-modular architecture of cortical networks, the singular critical point is replaced by an extended critical-like region that corresponds—in the jargon of statistical mechanics—to a Griffiths phase.

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Codewebs: Visualizing 40,000 student code submissions

Codewebs: Visualizing 40,000 student code submissions | Complex World | Scoop.it

Abstract Art?

     Not quite! The above figure is the landscape of ~40,000 student submissions to the same programming assignment on Coursera's Machine Learningcourse. Nodes represent submissions and edges are drawn between syntactically similar submissions. Colors correspond to performance on a battery of unit tests (with red submissions passing all unit tests). 
     In particular, clusters of similarly colored nodes correspond to multiple similar implementations that behaved in the same way (under unit tests).

 

** (For those curious, this particular programming assignment asked students to implement gradient descent for linear regression in Octave).

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Algorithm Writes People's Life Histories Using Twitter

Algorithm Writes People's Life Histories Using Twitter | Complex World | Scoop.it
“If you tweet about your life, a new algorithm can identify your most significant events and assemble them into an accurate life history, say the computer scientists who built it (Algorithm Writes People's Life Histories Using Twitter”
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luiy's curator insight, October 9, 2013 6:48 AM

Twitter allows anyone to describe their life in unprecedented detail. Many accounts provide an ongoing commentary of an individual’s interests, activities and opinions. 


So it’s not hard to imagine that it’s possible to reconstruct a person’s life history by analysing their Twitter stream.

But doing this automatically is trickier than it sounds. That’s because most Twitter streams contain news of important events mixed up with entirely trivial details about events of little or no significance. The difficulty is in telling these apart.


Ref:arxiv.org/abs/1309.7313 : Timeline Generation: Tracking individuals on Twitter

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Scientific publishing infographic

Scientific publishing infographic | Complex World | Scoop.it
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Bernard Ryefield's comment, October 5, 2013 6:29 AM
thank you for this; it's just unfortunate this sketch appears in the same issue as the biased Bohannon's paper
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The Mathematical Shape of Big Science Data

The Mathematical Shape of Big Science Data | Complex World | Scoop.it
Scientific data sets are becoming more dynamic, requiring new mathematical techniques on par with the invention of calculus.
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The Romanian Autumn Continues: The Dawn of Real Democracy in Romania?

The Romanian Autumn Continues: The Dawn of Real Democracy in Romania? | Complex World | Scoop.it

Despite a rainy and cold day in Bucharest, tens of thousands of Romanians took to the streets for the fifth Sunday consecutively to protest against a draft bill passed by the government approving a cyanide-based open-pit mining project.

The global youth-led Romanian initiative is currently the largest environmental protest movement in Europe and the world and continues to be a model of non-violent resistance.

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How Your Facebook Profile Reveals More About Your Personality Than You Know

How Your Facebook Profile Reveals More About Your Personality Than You Know | Complex World | Scoop.it

What do your status updates really say about you?

In a study published last week at PLOS ONE, scientists at the University of Pennsylvania examined the language used in 75,000 Facebook profiles. They found differences across ages, genders, and certain personality traits. This allowed the group, led by computer and information scientist H. Andrew Schwartz, to make predictions about the profile of each user.

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Viral Marketing Successfully Modeled By Network Theorists

Viral Marketing Successfully Modeled By Network Theorists | Complex World | Scoop.it
Network models famously fail to capture the dynamics of many real-world marketing campaigns. Now computer scientists say they’ve solved the problem.
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