A fractal hypernetwork model with good controllability

<abstract> <p>Fractal is a common feature of many deterministic complex networks. The complex networks with fractal features have interesting structure and good performance. The network based on hypergraph is named hypernetwork. In this paper, we construct a hypernetwork model with fractal properties, and obtain its topological properties. Moreover, according to the exact controllability theory, we obtain the node controllability and the hyperedge controllability of the fractal hypernetwork. The simulation results show that the measure of hyperedge controllability is smaller than that of node in the fractal hypernetwork. In addition, We compare the controllability of three types of hypernetwork, which are easier to control by their hyperedges. It is shown the fractal hypernetwork constructed in this paper has the best controllability. Because of the good controllability of our fractal hypernetwork model, it is suitable for the topology structure of many real systems.</p> </abstract>

Visualization of Sphere and Horosphere Packings Related to Coxeter Tilings by Simply Truncated Orthoschemes with Parallel Faces

In this paper we describe and visualize the densest ball and horoball packing configurations to the simply truncated 3-dimensional hyperbolic Coxeter orthoschemes with parallel faces, using the results of [24]. These beautiful packing arrangements describe and show the very interesting structure of the mentioned orthoschemes and the corresponding Coxeter reflection group. We use the Beltrami-Cayley-Klein ball model of 3-dimensional hyperbolic space H^3, the images were made by the Python programming language.

Design of Co1Al3(OH)m/carbon nitride hybrid nanostructures for enhanced capacitive energy storage in an alkaline electrolyte

Layered double hydroxide (LDH) nanostructures have attracted the attention of the scientific community owing to their facile synthesis, interesting structure and morphology, and have been promising in the field of energy storage applications.

Schwarzschild de Sitter and extremal surfaces

We study extremal surfaces in the Schwarzschild de Sitter spacetime with real mass parameter. We find codim-2 timelike extremal surfaces stretching between the future and past boundaries that pass through the vicinity of the cosmological horizon in a certain limit. These are analogous to the surfaces in http://arxiv.org/abs/1711.01107 [hep-th]. We also find spacelike surfaces that never reach the future/past boundaries but stretch indefinitely through the extended Penrose diagram, passing through the vicinity of the cosmological and Schwarzschild horizons in a certain limit. Further, these exhibit interesting structure for de Sitter space (zero mass) as well as in the extremal, or Nariai, limit.

TellTail: Fast Scoring and Detection of Dense Subgraphs

Suppose you visit an e-commerce site, and see that 50 users each reviewed almost all of the same 500 products several times each: would you get suspicious? Similarly, given a Twitter follow graph, how can we design principled measures for identifying surprisingly dense subgraphs? Dense subgraphs often indicate interesting structure, such as network attacks in network traffic graphs. However, most existing dense subgraph measures either do not model normal variation, or model it using an Erdős-Renyi assumption - but this assumption has been discredited decades ago. What is the right assumption then? We propose a novel application of extreme value theory to the dense subgraph problem, which allows us to propose measures and algorithms which evaluate the surprisingness of a subgraph probabilistically, without requiring restrictive assumptions (e.g. Erdős-Renyi). We then improve the practicality of our approach by incorporating empirical observations about dense subgraph patterns in real graphs, and by proposing a fast pruning-based search algorithm. Our approach (a) provides theoretical guarantees of consistency, (b) scales quasi-linearly, and (c) outperforms baselines in synthetic and ground truth settings.

New insights into phenazine-based organic redox flow batteries by using high-throughput DFT modelling

DFT calculations reveal interesting structure–property relationships of the redox potentials of phenazines in non-aqueous media.

Roof tile workshop in Mezőhegyes (Békés county, Hungary)

This study reports on an Árpád Period site in Mezőhegyes, where remains of an interesting structure were unearthed. Based on the design of the brickwork feature and the significant amount of corrupted roof tiles found in and around it, the structure must have functioned as a roof tile kiln. The best analogies for these roof tiles are found primarily in France (e.g., in Pontigny, Vermenton and Auxerre) and in Egres (Igriș, present-day Romania). Based on the findings, the analogies, and the history of Egres, it seems that the roof tile kiln of Mezőhegyes operated in the 12th century and can be connected to the activities of the Cistercian Order.

A series of anionic MOFs with cluster-based, pillared-layer and rod-spacer motifs: near-sunlight white-light emission and selective dye capture

A series of anionic MOFs with cluster-based, pillared-layer and rod-spacer motifs were constructed. Interesting structure features, near-sunlight white-light emission and selective dye capture were found.

Information hiding in geometric patterns and its application to fabric authentication

Geometric patterns have been used since ancient times as a means of decoration in art and architecture, with distinctive styles demonstrated in Islamic and Japanese cultures. They are now also being used as communication media, allowing information embedded in the pattern to be imparted in applications such as barcodes. By combining simple graphical tiles into geometric patterns, Professor Hiroshi Ito, from Nihon University in Japan, believes that the interesting structure of such patterns may make them less obstructive when printed onto materials, therefore making them easier to use in broader applications. Ito's focus lies in information binding to geometric patterns that encompass results for patterns known as dragon curves as well as Penrose tiling. This builds on his previous work using serpentine patterns, which involves manipulating two cells to create repetitive patterns reminiscent of the undulation of a snake. In this latest study, Ito and his colleagues consider the use of these patterns combined with a filter for use in applications such as document authentication.

Two Spot Coupled Ring Resonators

We consider a model of two coupled ring waveguides with constant linear gain and nonlinear absorption with space-dependent coupling. This system can be implemented in various physical situations as optical waveguides, atomic Bose-Einstein condensates, polarization condensates, etc. It is described by two coupled nonlinear Schrödinger equation. For numerical simulations, we take local two-gaussian coupling.It is found in our previous papers that, depending on the values of involved parameters, we can obtain several interesting nonlinear phenomena, which include spontaneous symmetry breaking, modulational instability leading to generation of stable circular flows with various vorticities, stable inhomogeneous states with interesting structure of currents flowing between rings, as well as dynamical regimes having signatures of chaotic behavior. This research will be associated with experimental investigation planned in Freie Universität Berlin, in the group of prof. Michael Giersig.