Critical behavior of a stochastic anisotropic Bak-Sneppen model

In this paper we present our study on the critical behavior of a stochastic anisotropic Bak-Sneppen (saBS) model, in which a parameter $\alpha$ is introduced to describe the interaction strength among nearest species. We estimate the threshold fitness $f_c$ and the critical exponent $\tau_r$ by numerically integrating a master equation for the distribution of avalanche spatial sizes. Other critical exponents are then evaluated from previously known scaling relations. The numerical results are in good agreement with the counterparts yielded by the Monte Carlo simulations. Our results indicate that all saBS models with nonzero interaction strength exhibit self-organized criticality, and fall into the same universality class, by sharing the universal critical exponents.Comment: 9 pages, 7 figures. arXiv admin note: text overlap with arXiv:cond-mat/9803068 by other author

Community detection by label propagation with compression of flow

The label propagation algorithm (LPA) has been proved to be a fast and effective method for detecting communities in large complex networks. However, its performance is subject to the non-stable and trivial solutions of the problem. In this paper, we propose a modified label propagation algorithm LPAf to efficiently detect community structures in networks. Instead of the majority voting rule of the basic LPA, LPAf updates the label of a node by considering the compression of a description of random walks on a network. A multi-step greedy agglomerative strategy is employed to enable LPAf to escape the local optimum. Furthermore, an incomplete update condition is also adopted to speed up the convergence. Experimental results on both synthetic and real-world networks confirm the effectiveness of our algorithm

Community Detection in Dynamic Networks via Adaptive Label Propagation

An adaptive label propagation algorithm (ALPA) is proposed to detect and monitor communities in dynamic networks. Unlike the traditional methods by re-computing the whole community decomposition after each modification of the network, ALPA takes into account the information of historical communities and updates its solution according to the network modifications via a local label propagation process, which generally affects only a small portion of the network. This makes it respond to network changes at low computational cost. The effectiveness of ALPA has been tested on both synthetic and real-world networks, which shows that it can successfully identify and track dynamic communities. Moreover, ALPA could detect communities with high quality and accuracy compared to other methods. Therefore, being low-complexity and parameter-free, ALPA is a scalable and promising solution for some real-world applications of community detection in dynamic networks.Comment: 16 pages, 11 figure

The effects of overtaking strategy in the Nagel-Schreckenberg model

Based on the Nagel-Schreckenberg (NS) model with periodic boundary conditions, we proposed the NSOS model by adding the overtaking strategy (OS). In our model, overtaking vehicles are randomly selected with probability $q$ at each time step, and the successful overtaking is determined by their velocities. We observed that (i) traffic jams still occur in the NSOS model; (ii) OS increases the traffic flow in the regime where the densities exceed the maximum flow density. We also studied the phase transition (from free flow phase to jammed phase) of the NSOS model by analyzing the overtaking success rate, order parameter, relaxation time and correlation function, respectively. It was shown that the NSOS model differs from the NS model mainly in the jammed regime, and the influence of OS on the transition density is dominated by the braking probability $p$Comment: 9 pages, 20 figures, to be published in The European Physical Journal B (EPJB

Design and performance analysis of dual vibrating motors self synchronous shaker with balanced elliptical motion

According to the basic principle of machine dynamics, the mechanical model of the dual vibrating motors self synchronous shaker with balanced elliptical motion is established. By virtual prototype technology, the kinematic and dynamic characteristic simulation analysis of the sieving box was carried out. The motion path, natural frequencies and mode shapes of the sieving box were calculated, the stress and deformation distribution in every part of the sieving box under rate load were obtained, and the dynamic strength analysis of the sieving box was carried out. The results show that, the structure design of the shaker is reasonable, and its dynamic strength is satisfied

Design and performance analysis of dual vibrating motors self synchronous shaker with balanced elliptical motion

According to the basic principle of machine dynamics, the mechanical model of the dual vibrating motors self synchronous shaker with balanced elliptical motion is established. By virtual prototype technology, the kinematic and dynamic characteristic simulation analysis of the sieving box was carried out. The motion path, natural frequencies and mode shapes of the sieving box were calculated, the stress and deformation distribution in every part of the sieving box under rate load were obtained, and the dynamic strength analysis of the sieving box was carried out. The results show that, the structure design of the shaker is reasonable, and its dynamic strength is satisfied

Прочность болтового фланцевого соединения стальной конструкции при землетрясении

Болтовое фланцевое соединение является одним из наиболее широко используемых видов соединения стальных конструкций. Его прочность при землетрясении обеспечивает сейсмостойкость стального каркаса. Предложены метод расчета прочности болтового фланцевого соединения стальных конструкций и конечноэлементная модель для расчета прочности фланцевого соединения стальной конструкции при землетрясении. При приложении односторонней статической и динамической нагрузки моделируется и рассчитывается прочность болтового фланцевого соединения. Результаты расчета показывают, что под действием землетрясения толщина фланца незначительно влияет на площадь контакта, но оказывает большое влияние на напряжение в зоне контакта. Под действием землетрясения, когда стенка колонны и балка деформируются одновременно, деформации изгиба являются самыми полными, коэффициент рассеивания энергии и параметры сейсмических воздействий оказываются наибольшими. Аналитические результаты использованных методов хорошо согласуются с реальными значениями, а коэффициент совпадения превышает значение 0.9900

Bacterial diversity and community in Qula from the Qinghai–Tibetan Plateau in China

Qula is a cheese-like product usually prepared with unpasteurized yak milk under open conditions, with both endogenous and exogenous microorganisms involved in the fermentation process. In the present study, 15 Qula samples were collected from five different regions in China to investigate the diversity of microbial communities using high-throughput sequencing targeting the V3–V4 region of 16S rRNA gene. The bacterial diversity significantly differed among samples of different origins, indicating a possible effect of geography. The result also showed that microbial communities significantly differed in samples of different origin and these differences were greater at the genus than the phylum level. A total of six phyla were identified in the samples, and Firmicutes and Proteobacteria had a relative abundance >20%. A total of 73 bacterial genera were identified in the samples. Two dominant genera (Lactobacillus and Acetobacter) were common to all samples, and a total of 47 operational taxonomic units at different levels significantly differed between samples of different origin. The predicted functional genes of the bacteria present in samples also indicated differences in bacterial communities between the samples of different origin. The network analysis showed that microbial interactions between bacterial communities in Qula were very complex. This study lays a foundation for further investigations into its food ecology