Remember me

Register  |   Lost password?

Introduction to QuantLib Development - Intensive 3-day Training Course - September 10-12th, 2018 - Download Registration Form Here


Recent members



Complexity Digest wrote a new blog post titled Stability of democracies: a complex systems perspective
The idea that democracy is under threat, after being largely dormant for at least 40 years, is looming increasingly large in public discourse. Complex systems theory offers a range of powerful new tools to analyse the stability of social institutions in general, and democracy in particular. What makes a democracy stable? And which processes potentially lead to instability of a democratic system? This paper offers a complex systems perspective on this question, informed by areas of the mathematical, natural, and social sciences. We explain the meaning of the term ‘stability’ in...
74 days ago
Complexity Digest wrote a new blog post titled Consciousness: The last 50 years (and the next)
The mind and brain sciences began with consciousness as a central concern. But for much of the 20th century, ideological and methodological concerns relegated its empirical study to the margins. Since the 1990s, studying consciousness has regained a legitimacy and momentum befitting its status as the primary feature of our mental lives. Nowadays, consciousness science encompasses a rich interdisciplinary mixture drawing together philosophical, theoretical, computational, experimental, and clinical perspectives, with neuroscience its central discipline. Researchers have learned a great deal...
75 days ago
Complexity Digest wrote a new blog post titled Conference on Complex Systems 2019
The Conference on Complex Systems (CCS) is the biggest and most important annual meeting of the international complex systems community. It comes under the auspices of the Complex Systems Society. Since its inception in 2004, CCS had always been Europe-based, but in 2015 & 2017, it moved to North & Latin America respectively. In 2019, CCS will come to Asia for the first time. Held in Singapore at Nanyang Technological University, it promises an intellectually stimulating experience to be matched by an equally exciting social programme. ​ Source:
76 days ago
Complexity Digest wrote a new blog post titled Beyond Calories: A Holistic Assessment of the Global Food System
The global food system is failing to meet nutritional needs, with growing concerns for health related to both under-, over-consumption and severe micronutrient deficiency. The 2nd Sustainable Development Goal (SDG2) targets the end of malnutrition in all forms by 2030. To address this challenge, the focus around food security and malnutrition must be broadened beyond the scope of sufficient energy intake to take full account of total nutrient supply and requirements. Here, for the first time, we have quantitatively mapped the global food system in terms of energy, protein, fat, essential...
76 days ago
Complexity Digest wrote a new blog post titled A structural transition in physical networks
In many physical networks, including neurons in the brain1,2, three-dimensional integrated circuits3 and underground hyphal networks4, the nodes and links are physical objects that cannot intersect or overlap with each other. To take this into account, non-crossing conditions can be imposed to constrain the geometry of networks, which consequently affects how they form, evolve and function. However, these constraints are not included in the theoretical frameworks that are currently used to characterize real networks5,6,7. Most tools for laying out networks are variants of the force-directed...
76 days ago
Complexity Digest wrote a new blog post titled The Impact of Potential Crowd Behaviours on Emergency Evacuation
Crowd dynamics have important applications in evacuation management systems relevant to organizing safer large scale gatherings. For crowd safety, it is very important to study the evolution of potential crowd behaviours by simulating the crowd evacuation process. Planning crowd control tasks via studying the impact of crowd behavioural evolution towards evacuation simulation could mitigate the possibility of crowd disasters that may happen. During a typical emergency evacuation scenario, conflict among agents occurs when agents intend to move to the same location as a result of the...
76 days ago
Complexity Digest wrote a new blog post titled AI for the Common Good?! Pitfalls, challenges, and Ethics Pen-Testing
Recently, many AI researchers and practitioners have embarked on research visions that involve doing AI for "Good". This is part of a general drive towards infusing AI research and practice with ethical thinking. One frequent theme in current ethical guidelines is the requirement that AI be good for all, or: contribute to the Common Good. But what is the Common Good, and is it enough to want to be good? Via four lead questions, I will illustrate challenges and pitfalls when determining, from an AI point of view, what the Common Good is and how it can be enhanced by AI. The questions...
78 days ago
Complexity Digest wrote a new blog post titled Quantifying the sensing power of crowd-sourced vehicle fleets
Sensors can measure air quality, traffic congestion, and other aspects of urban environments. The fine-grained diagnostic information they provide could help urban managers to monitor a city’s health. Recently, a `drive-by’ paradigm has been proposed in which sensors are deployed on third-party vehicles, enabling wide coverage at low cost} Research on drive-by sensing has mostly focused on sensor engineering, but a key question remains unexplored: How many vehicles would be required to adequately scan a city? Here, we address this question by analyzing the sensing power of a taxi...
79 days ago
Complexity Digest wrote a new blog post titled Statistical physics of liquid brains
Liquid neural networks (or ”liquid brains”) are a widespread class of cognitive living networks characterised by a common feature: the agents (ants or immune cells, for example) move in space. Thus, no fixed, long-term agent-agent connections are maintained, in contrast with standard neural systems. How is this class of systems capable of displaying cognitive abilities, from learning to decision-making? In this paper, the collective dynamics, memory and learning properties of liquid brains is explored under the perspective of statistical physics. Using a comparative approach, we...
80 days ago
Complexity Digest wrote a new blog post titled The Crisis of Reproducibility, the Denominator Problem and the Scientific Role of Multi-scale Modeling
The “Crisis of Reproducibility” has received considerable attention both within the scientific community and without. While factors associated with scientific culture and practical practice are most often invoked, I propose that the Crisis of Reproducibility is ultimately a failure of generalization with a fundamental scientific basis in the methods used for biomedical research. The Denominator Problem describes how limitations intrinsic to the two primary approaches of biomedical research, clinical studies and preclinical experimental biology, lead to an inability to effectively characterize...
82 days ago
Complexity Digest wrote a new blog post titled Optimal Sequence Memory in Driven Random Networks
Autonomous, randomly coupled, neural networks display a transition to chaos at a critical coupling strength. Here, we investigate the effect of a time-varying input on the onset of chaos and the resulting consequences for information processing. Dynamic mean-field theory yields the statistics of the activity, the maximum Lyapunov exponent, and the memory capacity of the network. We find an exact condition that determines the transition from stable to chaotic dynamics and the sequential memory capacity in closed form. The input suppresses chaos by a dynamic mechanism, shifting the transition...
83 days ago
Complexity Digest wrote a new blog post titled Quantifying Biases in Online Information Exposure
Our consumption of online information is mediated by filtering, ranking, and recommendation algorithms that introduce unintentional biases as they attempt to deliver relevant and engaging content. It has been suggested that our reliance on online technologies such as search engines and social media may limit exposure to diverse points of view and make us vulnerable to manipulation by disinformation. In this article, we mine a massive data set of web traffic to quantify two kinds of bias: (i) homogeneity bias, which is the tendency to consume content from a narrow set of information sources,...
85 days ago
Complexity Digest wrote a new blog post titled The Model Thinker: What You Need to Know to Make Data Work for You: Scott E. Page
From the stock market to genomics laboratories, census figures to marketing email blasts, we are awash with data. But as anyone who has ever opened up a spreadsheet packed with seemingly infinite lines of data knows, numbers aren’t enough: we need to know how to make those numbers talk. In The Model Thinker, social scientist Scott E. Page shows us the mathematical, statistical, and computational models–from linear regression to random walks and far beyond–that can turn anyone into a genius. At the core of the book is Page’s "many-model paradigm," which shows...
85 days ago
Complexity Digest wrote a new blog post titled Alife 2019: The 2019 Conference on Artificial Life
How Can Artificial Life Help Solve Societal Challenges? Artificial Life has historically been regarded by its adversaries as an academic “hobby” with little relation to real life. We feel that these days are past, as in fact, our interdisciplinary and constantly self-innovating discipline brings together a set of skills and perspectives with a unique potential to tackle some of the most pressing societal challenges of our times. The theme “How can Artificial Life help to solve Societal Challenges” will run through the conference in the shape of keynote presentations and satellite events that...
85 days ago
Complexity Digest wrote a new blog post titled Multiscale impact of researcher mobility
International mobility facilitates the exchange of scientific, institutional and cultural knowledge. Yet whether globalization and advances in virtual communication technologies have altered the impact of researcher mobility is a relevant and open question that we address by analysing a broad international set of 26 170 physicists from 1980 to 2009, focusing on the 10-year period centred around each mobility event to assess the impact of mobility on research outcomes. We account for secular globalization trends by splitting the analysis into three periods, measuring for each period the effect...
85 days ago
Complexity Digest wrote a new blog post titled Rank-frequency distribution of natural languages: a difference of probabilities approach
The time variation of the rank k of words for six Indo-European languages is obtained using data from Google Books. For low ranks the distinct languages behave differently, maybe due to syntaxis rules, whereas for k>50 the law of large numbers predominates. The dynamics of k is described stochastically through a master equation governing the time evolution of its probability density, which is approximated by a Fokker-Planck equation that is solved analytically. The difference between the data and the asymptotic solution is identified with the transient solution, and good agreement is...
85 days ago
Complexity Digest wrote a new blog post titled Measurability of the epidemic reproduction number in data-driven contact networks
The analysis of real epidemiological data has raised issues of the adequacy of the classic homogeneous modeling framework and quantities, such as the basic reproduction number in real-world situations. Based on high-quality sociodemographic data, here we generate a multiplex network describing the contact pattern of the Italian and Dutch populations. By using a microsimulation approach, we show that, for epidemics spreading on realistic contact networks, it is not possible to define a steady exponential growth phase and a basic reproduction number. We show the operational use of the...
86 days ago
Complexity Digest wrote a new blog post titled Bio-inspired computing: Algorithms review, deep analysis, and the scope of applications
Bio-inspired computing represents the umbrella of different studies of computer science, mathematics, and biology in the last years. Bio-inspired computing optimization algorithms is an emerging approach which is based on the principles and inspiration of the biological evolution of nature to develop new and robust competing techniques. In the last years, the bio-inspired optimization algorithms are recognized in machine learning to address the optimal solutions of complex problems in science and engineering. However, these problems are usually nonlinear and restricted to multiple nonlinear...
87 days ago
Complexity Digest wrote a new blog post titled Artificial Intelligence Hits the Barrier of Meaning
As someone who has worked in A.I. for decades, I’ve witnessed the failure of similar predictions of imminent human-level A.I., and I’m certain these latest forecasts will fall short as well. The challenge of creating humanlike intelligence in machines remains greatly underestimated. Today’s A.I. systems sorely lack the essence of human intelligence: understanding the situations we experience, being able to grasp their meaning. The mathematician and philosopher Gian-Carlo Rota famously asked, “I wonder whether or when A.I. will ever crash the barrier of meaning.” To me, this is still the most...
88 days ago
Complexity Digest wrote a new blog post titled Credit Is About Perception More Than Performance
I first learned about Douglas Prasher three years ago, when an algorithm we’d just developed made an unpredictable prediction: He should have been a recipient of the 2008 Nobel Prize. Instead, the award had been given to three other scientists. Even more surprising was our inability to find Prasher anywhere. He wasn’t on the faculty at any university. We couldn’t locate him at an industrial research lab. In fact, as we started digging for him, we realized that he hadn’t written a research paper in nearly a decade. It was truly puzzling. This fellow, who, according to our algorithm, deserved a...
89 days ago