The evolution of a barrier island and its stratigraphic architecture is investigated with the numerical model BIT (barrier island translation). The model simulates, with simplified equations, the effects of various processes (wind waves, storm surges, sea-level oscillations) on sediment location and characteristics. The presented formulation is able to reproduce both the cross-shore profile and...

The determination of a steeply falling energy spectrum from rare events with nongaussian measurement errors is a delicate matter. The final shape of the spectrum may be severely distorted as a consequence of non-gaussian tails in the energy resolution of the experiment. We illustrate this effect with the recent experimental efforts to determine the ultra-high energy extreme of the cosmic ray sp...

A significant body of social science research has concluded that improvisation in distributed, collaborative, open systems is the key to success in responding to and recovering from extreme events. The evolution of emergency management in the United States since the 9-11 attacks has emphasized the development of doctrine, process, and structure. In earlier work I concluded that both the agility...

We review the opinion dynamics in the computer models of Deffuant et al. (D), of Krause and Hegselmann (KH), and of Sznajd (S). All these models allow for consensus (one final opinion), polarization (two final opinions), and fragmentation (more than two final opinions), depending on how tolerant people are to different opinions. We then simulate the reactions of people to extreme events, in tha...

We consider a single-server first-in-first-out queue fed by a finite number of distinct sources of jobs. For a large class of short-range dependent and light-tailed distributed job processes, using functional large deviation techniques we prove a large deviation principle and logarithmic asymptotics for the joint waiting time and queue lengths distribution. We identify the paths that are most l...

The Great Filter refers to a highly speculative theory that implicitly claims one can test, via a probability model, whether known aspects of the history of life on Earth are consistent with the hypothesis that emergence of intelligent life was very unlikely. We describe the theory and some of the many objections to it. We give a mathematical argument to show that one objection, namely that it ...

Reward shaping allows reinforcement learning (RL) agents to accelerate learning by receiving additional reward signals. However, these signals can be difficult to design manually, especially for complex RL tasks. We propose a simple and general approach that determines the reward of pre-defined events by their rarity alone. Here events become less rewarding as they are experienced more often, w...

Learning to predict rare events from sequences of events with categorical features is an important, real-world, problem that existing statistical and machine learning methods are not well suited to solve. This paper describes timeweaver, a genetic algorithm based machine learning system that predicts rare events by identifying predictive temporal and sequential patterns. Timeweaver is applied t...

Since 2005, Google has conducted the largest corporate experiment with prediction markets we are aware of. In this paper, we illustrate how markets can be used to study how an organization processes information. We show that market participants are not typical of Google’s workforce, and that market participation and success is skewed towards Google’s engineering and quantitatively oriented empl...

The geospace is very sensitive to solar and geomagnetic activity, to changes in these activities and its manifestations in the near-Earth space environment and on the Earth. The Sun, as the origin of visible and invisible influence, poses a health and safety threat to humans and all kinds of human activities. This paper describes recently obtained results of cross-disciplinary heliobiological s...