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

Stochastic processes of interacting particles in systems with varying length are relevant e.g. for several biological applications. We try to explore what kind of new physical effects one can expect in such systems. As an example, we extend the exclusive queueing process that can be viewed as a one-dimensional exclusion process with varying length, by introducing Langmuir kinetics. This process can be interpreted as an effective model for a queue that interacts with other queues by allowing incoming and leaving of customers in the bulk. We find surprising indications for breaking of ergodicity in a certain parameter regime, where the asymptotic growth behavior depends on the initial length. We show that a random walk with site-dependent hopping probabilities exhibits qualitatively the same behavior.

Effective ergodicity breaking in an exclusion process with varying system length

Large crowds are challenging the comfort and safety level of big cities, while music may be a potential method to improve pedestrian flow. This paper focuses on the influence of different tempos and types of background music on pedestrian dynamics. Three tempos (90[Formula: see text]beats/min (BPM), 120[Formula: see text]BPM and 150[Formula: see text]BPM) and two types (pure music and metronome stimuli) of music are considered. It is found that more frequent stop-and-go behaviors emerge with rhythms. Compared with that under a low tempo (90[Formula: see text]BPM) of rhythm condition, stopping is more frequent with a high tempo one (120[Formula: see text]BPM or 150[Formula: see text]BPM). The number of stopping pedestrians per unit time increases 68.57%, 376.00%, 298.29%, 224.00%, 438.29% and 393.71% with 90 BPM, 120[Formula: see text]BPM and 150[Formula: see text]BPM music, 90[Formula: see text]BPM, 120[Formula: see text]BPM and 150[Formula: see text]BPM metronome, compared with that without any rhythm, respectively. The velocity and flow are lower, and higher local densities appear with background music. The step frequency at high density with rhythms ([Formula: see text], [Formula: see text] and [Formula: see text][Formula: see text]Hz for 90[Formula: see text]BPM, 120[Formula: see text]BPM and 150[Formula: see text]BPM music; [Formula: see text], [Formula: see text] and [Formula: see text][Formula: see text]Hz for 90[Formula: see text]BPM, 120[Formula: see text]BPM and 150[Formula: see text]BPM metronome) is lower than that without any rhythm ([Formula: see text][Formula: see text]Hz). Pedestrians need more time to avoid collisions and to step under background music conditions, because they are influenced by the music and not fully focusing on walking. As a result, step frequency decreases and stopping behavior is more frequent. This in turn leads to the decrease of the velocity and flow and the emergence of higher local densities. Our study will be helpful for understanding the effect of background music on pedestrian dynamics.

Pedestrian dynamics in single-File movement under Background Music with Different Tempos

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 a new method to solve the nested Bethe Ansatz equations for the one-dimensional Hubbard model. First the “spin problem” is solved completely by using inversion/functional relations and an equivalence to the eight-vertex model. Secondly we solve the “electronic problem”, i.e. we determine the ground state of the half-filled band and all finite energy excitations relative to this case. Apart from the calculation of the energy bands we also derive basic equations for the characteristic parameters which determine the excited states.

A new method for the excitations of the one-dimensional Hubbard model *'**

We use analytical methods to investigate cellular automata for traffic flow. Two different mean-field approaches are presented, which we call site-oriented and car-oriented, respectively. The car-oriented mean-field theory yields the exact fundamental diagram for the model with maximum velocity $\vm =1$ whereas in the site-oriented approach one has to take into account correlations between nearest-neighbour sites. Going beyond mean-field using the so-called $n$-cluster approach our results for $\vm >1$ are in excellent agreement with numerical simulations. We also present a modified cellular automaton which is closely related to a two-dimensional dimer model.

Andreas Schadschneider

Papers

Effective ergodicity breaking in an exclusion process with varying system length

Pedestrian dynamics in single-File movement under Background Music with Different Tempos

Traffic patterns and flow characteristics in an ant trail model

A new method for the excitations of the one-dimensional Hubbard model *'**

Cellular Automata For Traffic Flow: Analytical Results