There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

Statistical physics has proven to be a fruitful framework to describe phenomena outside the realm of traditional physics. Recent years have witnessed an attempt by physicists to study collective phenomena emerging from the interactions of individuals as elementary units in social structures. A wide list of topics are reviewed ranging from opinion and cultural and language dynamics to crowd behavior, hierarchy formation, human dynamics, and social spreading. The connections between these problems and other, more traditional, topics of statistical physics are highlighted. Comparison of model results with empirical data from social systems are also emphasized.

Statistical physics of social dynamics

N G van Kampen 1981 Amsterdam: North-Holland xiv + 419 pp price Dfl 180 This is a book which, at a lower price, could be expected to become an essential part of the library of every physical scientist concerned with problems involving fluctuations and stochastic processes, as well as those who just enjoy a beautifully written book. It provides an extensive graduate-level introduction which is clear, cautious, interesting and readable.

https://iopscience.iop.org/article/10.1088/0031-9112/34/4/040/pdf

Stochastic Processes in Physics and Chemistry

From the Publisher: 
The accessible presentation of this book gives both a general view of the entire computer vision enterprise and also offers sufficient detail to be able to build useful applications. Users learn techniques that have proven to be useful by first-hand experience and a wide range of mathematical methods. A CD-ROM with every copy of the text contains source code for programming practice, color images, and illustrative movies. Comprehensive and up-to-date, this book includes essential topics that either reflect practical significance or are of theoretical importance. Topics are discussed in substantial and increasing depth. Application surveys describe numerous important application areas such as image based rendering and digital libraries. Many important algorithms broken down and illustrated in pseudo code. Appropriate for use by engineers as a comprehensive reference to the computer vision enterprise.

Computer vision : a modern approach = 计算机视觉 : 一种现代的方法

We have constructed a minimal cellular automaton model for simulating traffic on preexisting ant trails. Uni- as well as bidirectional trails are investigated and characteristic patterns in the distribution of workers on the trail are identified. Some of these patterns have already been observed empirically. They give rise to unusual flow characteristics which are also discussed. The question of possible functions of the observed traffic patterns and the resulting flow characteristics will be treated for simplified biological scenarios.

Traffic Patterns and Flow Characteristics in an Ant Trail Model

We present empirical results for traffic flow on ant trails. The observed spatio-temporal organization of the ants as well as quantitative results for the fundamental diagram and headway distributions are compared with predictions of a cellular automaton model. In sharp contrast to highway traffic, no jammed phase is observed and the average velocity is almost independent of the density of ants.

Traffic Flow on Ant Trails: Empirical Results vs. Theoretical Predictions

The modelling of traffic flow using methods and models from physics has a long history. In recent years especially cellular automata models have allowed for large-scale simulations of large traffic networks faster than real time. On the other hand, these systems are interesting for physicists since they allow to observe genuine nonequilibrium effects. Here the current status of cellular automata models for traffic flow is reviewed with special emphasis on nonequilibrium effects (e.g. phase transitions) induced by on- and off-ramps.

Statistical Physics of Traffic Flow

In recent years, the measures to interfere the crowds movement with physical facilities (such as channelizing, separation railing) have become more and more common, but how they affect the crowd movement and what moving risks exist in the entrance confluence area have not been fully revealed. Therefore, this paper analyzes the moving risk of the crowds before the bottleneck entrance area, in the presence of the channelizing barriers by controllable laboratory experiments. The visual color cloud charts of the local density, speed and confusion degree of moving directions within the entrance confluence area are analyzed in the presence of different gaps (1.05m and 0.7m) channelizing barriers, to further quantify the motion risk of the crowds. The study finds that the narrower gaps of the channelizing railings, the larger area of high-risk zones, and they have clear ‘lane formation’ effect in shaping the risk zones. The both ends of the channelizing barriers are higher moving risk zones for multi-entry sides conditions, but the area before the middle channels also needs to be closely concerned when the participants entering from two opposite entering sides. The study will provide theoretical basis for evaluating the safety of the setting conditions of the channelizing barriers and conducting scientific crowd management decisions.

Moving Risk of Crowds in the Entrance Confluence Area in the Presence of Channelizing Facilities

We consider the asymmetric random average process which is a one-dimensional stochastic lattice model with nearest neighbour interaction but continuous and unbounded state variables. First, the explicit functional representations, so-called beta densities, of all local interactions leading to steady states of product measure form are rigorously derived. This also completes an outstanding proof given in a previous publication. Then, we present an alternative solution for the processes with factorized stationary states by using a matrix product ansatz. Due to continuous state variables we obtain a matrix algebra in form of a functional equation which can be solved exactly.

Andreas Schadschneider

Papers

Traffic Patterns and Flow Characteristics in an Ant Trail Model

Traffic Flow on Ant Trails: Empirical Results vs. Theoretical Predictions

Statistical Physics of Traffic Flow

Moving Risk of Crowds in the Entrance Confluence Area in the Presence of Channelizing Facilities

Matrix product approach for the asymmetric random average process