Two fundamental issues surrounding research on Zipf's law regarding city sizes are whether and why Zipf's law holds. This paper does not deal with the latter issue with respect to why, and instead investigates whether Zipf's law holds in a global setting, thus involving all cities around the world. Unlike previous studies, which have mainly relied on conventional census data, and census- bureau-imposed definitions of cities, we adopt naturally and objectively delineated cities, or natural cities, to be more precise, in order to examine Zipf's law. We find that Zipf's law holds remarkably well for all natural cities at the global level, and remains almost valid at the continental level except for Africa at certain time instants. We further examine the law at the country level, and note that Zipf's law is violated from country to country or from time to time. This violation is mainly due to our limitations; we are limited to individual countries, and to a static view on city-size distributions. The central argument of this paper is that Zipf's law is universal, and we therefore must use the correct scope in order to observe it. We further find that this law is reflected in the distribution of cities: the number of cities in individual countries follows an inverse power relationship; the number of cities in the first largest country is twice as many as that in the second largest country, three times as many as that in the third largest country, and so on.
Zipf's Law for All the Natural Cities around the World Bin Jiang, Junjun Yin, Qingling Liu
Cities around the world are growing faster than you can say megalopolis. More than half the world lives in cities, and by 2050, it will be two-thirds. In China alone, 300 million people will move to the city within the next 15 years, and to serve them, China must build the equivalent of the entire built infrastructure of the United States by 2028. At the same time, 250 million new urban dwellers are expected in India and 380 million in Africa. Even though cities will soon account for 90 percent of population growth, 80 percent of global CO2, and 75 percent of energy consumption, more and more, it’s where people want to live. Why? Because it’s where 80 percent of the wealth is created, and it’s where people find opportunities, especially women in the developing world. But beyond basic needs from housing to jobs, how do we enjoy the benefits of the city—like cafes, art galleries, restaurants, cultural facilities—without the traffic, crowding, crime, pollution, and disease?
Big Bang cosmology, chemical and biological evolutionary theory, and associated sciences have been extraordinarily successful in revealing and enabling us to understand the development of the universe from the Planck era to the present, as well as the emergence of complexity, life, and consciousness here on Earth. After briefly sketching this amazing story, and the key characteristics of nature, this paper will reflect on the different types and levels of causality involved -- stressing the important and pervasive role of highly differentiated and dynamic relationships and networks of relationships. Philosophical considerations build on and enrich scientific ones to probe these relationships. They also take us beyond the limits of strictly scientific methodology to consider and model -- however inadequately -- the ultimate sources of existence and order. This is the issue of creation, which introduces another very different -- and transcendent -- level of causality. We show that this is compatible with the -- and even essential to -- the causalities operative in nature, including those of quantum cosmology, if we acknowledge the limits of physics.
This lecture was delivered by George Ellis during the 16th Kraków Methodological Conference "The Causal Universe", May 17-18, 2012.
What makes a meme— an idea, a phrase, an image—go viral? For starters, the meme must have broad appeal, so it can spread not just within communities of like-minded individuals but can leap from one community to the next. Researchers, by mining public Twitter data, have found that a meme's “virality” is often evident from the start. After only a few dozen tweets, a typical viral meme (as defined by tweets using a given hashtag) will already have caught on in numerous communities of Twitter users. In contrast, a meme destined to peter out will resonate in fewer groups.
The “study of complexity” refers to the attempt to find common principles underlying the behavior of complex systems—systems in which large collections of components interact in nonlinear ways. Here, the term nonlinear implies that the system can’t be understood simply by understanding its individual components; nonlinear interactions cause the whole to be “more than the sum of its parts.”
How Can the Study of Complexity Transform Our Understanding of the World?
Many species dream, yet there remain many open research questions in the study of dreams. The symbolism of dreams and their interpretation is present in cultures throughout history. Analysis of online data sources for dream interpretation using network science leads to understanding symbolism in dreams and their associated meaning. In this study, we introduce dream interpretation networks for English, Chinese and Arabic that represent different cultures from various parts of the world. We analyze communities in these networks, finding that symbols within a community are semantically related. The central nodes in communities give insight about cultures and symbols in dreams. The community structure of different networks highlights cultural similarities and differences. Interconnections between different networks are also identified by translating symbols from different languages into English. Structural correlations across networks point out relationships between cultures. Similarities between network communities are also investigated by analysis of sentiment in symbol interpretations. We find that interpretations within a community tend to have similar sentiment. Furthermore, we cluster communities based on their sentiment, yielding three main categories of positive, negative, and neutral dream symbols.
António F Fonseca's insight:
Very interesting research work based on web content.
Recent advances on human dynamics have focused on the normal patterns of human activities, with the quantitative understanding of human behavior under extreme events remaining a crucial missing chapter. This has a wide array of potential applications, ranging from emergency response and detection to traffic control and management. Previous studies have shown that human communications are both temporally and spatially localized following the onset of emergencies, indicating that social propagation is a primary means to propagate situational awareness. We study real anomalous events using country-wide mobile phone data, finding that information flow during emergencies is dominated by repeated communications. We further demonstrate that the observed communication patterns cannot be explained by inherent reciprocity in social networks, and are universal across different demographics.
Quantifying Information Flow During Emergencies Liang Gao, Chaoming Song, Ziyou Gao, Albert-László Barabási, James P. Bagrow & Dashun Wang
Animal behavior isn't complicated, but it is complex. Nicolas Perony studies how individual animals -- be they Scottish Terriers, bats or meerkats -- follow simple rules that, collectively, create larger patterns of behavior. And how this complexity born of simplicity can help them adapt to new circumstances, as they arise.
NEWS.com.au Google raises concerns with purchase of 'strong' artificial intelligence developer allvoices Mountain View claims they are building on a chance to break into the field of industry automation, not our collective consciousness.
António F Fonseca's insight:
The owner of a significant portion of earth's curiosity patrimony is turning into deep AI.
It is generally recognized that life is becoming more complex. This article analyzes the human social environment using the "complexity proﬁle," a mathematical tool for characterizing the collective behavior of a system. The analysis is used to justify the qualitative observation that complexity of existence has increased and is increasing. The increase in complexity is directly related to sweeping changes in the structure and dynamics of human civilization—the increasing interdependence of the global economic and social system, and the instabilities of dictatorships, communism and corporate hierarchies. Our complex social environment is consistent with identifying global human civilization as an organism capable of complex behavior that protects its components (us) and which should be capable of responding eﬀectively to complex environmental demands
(Phys.org) —The question of how an economic system should be structured in order to best promote fairness and equality is one of the most debated subjects of all time. By approaching the complexities of this question from the field of network science, researchers from MIT and other institutions have found that the average degree to which individuals in a society are connected to each other can crucially affect the fairness of income distribution.
The éToile Platform is an open, interactive, new way of sharing educational resources for Master and PhD levels in Complexity Sciences domains.
In different modules, students and researchers can:
check their knowledge using the étoile evaluation tests;interact with other people studying the same subjects;use the éToile facilities for studying and researching on the Internet;contribute for an ecology of pedagogical resources;certificated their mastery of a core curriculum in Complexity Sciences;interact with a worldwide community of students and scientific researchers within the CS-Digital Campus.