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    Quantum criticality in spin-1/2 anisotropic XY model with staggered Dzyaloshinskii-Moriya interaction

    Su, Yao HengLiu, D. C.Wan, ZhongyuChen, Ai Min...
    9页
    查看更多>>摘要：By utilizing the infinite time evolving block decimation method in infinite matrix product state representation, the quantum criticality and critical exponents varying are investigated in the spin-1/2 anisotropic XY chain with staggered Dzyaloshinskii-Moriya interaction. The phase diagram is obtained from the entanglement measurement, where a XY phase line delta = 0 separates the Neel phase. Along this critical line, the central charge c = 1 is extracted from the finite entanglement and the finite correlation length. In addition, the characteristic critical exponents are obtained from the local transverse magnetization, nonlocal transverse Neel order, and the correlation length, respectively. It is found that all the critical exponents are varying continuously along the phase transition line delta = 0, and the ratios of critical exponents imply that the phase transition is in conformity with the weak universality. The linear relations of the critical exponents are able to illustrate the dependence between the critical exponents and the Dzyaloshinskii-Moriya interaction. C) 2022 Elsevier B.V. All rights reserved.
      原文链接:
    • NSTL
    • Elsevier

    NetVIX - A network volatility index of financial markets

    Ahelegbey, Daniel FelixGiudici, Paolo
    17页
    查看更多>>摘要：We construct a network volatility index (NetVIX) via market interconnectedness and volatilities to measure global market risk. The NetVIX multiplicatively decomposes into a network volatility effect and a network contagion effect. It also additively decomposes into volatility contributions of each market. We apply our measure to study the relationship between the interconnectedness among 20 major stock markets and global market risks over the last two decades. We show that the NetVIX has a strong relationship with the VIX index, and therefore able to reliably signal changes in global market volatility. We also show that while the NetVIX tracks to some extent the VIX, it provides much more information about the level of volatility and contagion effects in financial markets. The result shows that during crisis periods, particularly the tech bubble, the global financial crisis, and the Covid-19 pandemic, stock market interconnectedness contributes to global market turmoil by amplifying average market volatility with over 400 percent multiplier. Also during crisis times, the level of risk is relatively higher and more persistent in the US and German markets, which implies market losses for investors with long exposures. The results also reveal that the highest risk-contributing markets are the US, Brazil, Hong Kong, France, and Germany. (c) 2022 Elsevier B.V. All rights reserved.
      原文链接:
    • NSTL
    • Elsevier

    A novel method for forecasting time series based on directed visibility graph and improved random walk

    Hu, YuntongXiao, Fuyuan
    11页
    查看更多>>摘要：Recently network-based method for forecasting time series has become a hot research topic. Although some proposed network-based methods achieve good performance in forecasting some series, how to mine more information of time series and make more accurate predictions is still an open question. To address this issue, we propose a novel reconstructing-forecasting method based on directed visibility graph and random walk process. Firstly, the observed time series is reconstructed to explore more information of series. Then, the reconstructed series is converted into a directed visibility graph. Af-terwards, the reconstructed series is predicted with the similarity distribution obtained from improved random walk process. Eventually, the prediction of original time series is calculated using the predictions and the similarity distribution of the reconstructed one. To test the forecasting performance, the proposed method is applied to forecast construction cost index (CCI), China's quarterly total GDP growth (GDP) and China's tertiary industry quarterly GDP growth (TI). The results of experiments indicate that, with good robustness, the proposed method is of ability to provide more accurate predictions than compared methods.
      原文链接:
    • NSTL
    • Elsevier

    Suppressing traffic-driven epidemic spreading in multiplex networks by effective traffic-flow assignment strategy

    Jing, Xing-LiHu, Mao-BinChen, Jie
    11页
    查看更多>>摘要：Despite extensive research on the interplay between traffic dynamics and epidemic spreading, the control of epidemic spreading in multiplex networks by routing strategies has not received adequate attention. In this paper, we study the impact of effective traffic-flow assignment strategy on epidemic spreading in multiplex networks. Interestingly, epidemic spreading can be effectively controlled by tuning the routing assignment in a certain layer. In particular, by adjusting the routing parameters, the epidemic can be completely suppressed. Moreover, an increase in the average network connectivity of one layer of the multiplex networks can also suppress the outbreak of epidemic spreading. By both simulation and theoretical analysis, the epidemic suppression effect is confirmed on multiplex networks composed of Erdos-Renyi random and Scale-Free layers. (C) 2022 Elsevier B.V. All rights reserved.
      原文链接:
    • NSTL
    • Elsevier

    Pinning control strategy and stability analysis of mixed platoon: A cyber-physical perspective

    Liu, ZhongchengSun, DihuaZhao, MinJin, Shuang...
    23页
    查看更多>>摘要：Control of mixed traffic, consisting of manual driving vehicles and automated driving vehicles, remains a major challenge. In this paper, a novel pinning control strategy for mixed platoon to achieve indirect control of manual driving vehicles is proposed. Besides the control algorithm of pinning nodes, the impact of the spatial distribution of automated driving vehicles on traffic is studied. The approach is compatible with the existing control of automated driving vehicles in mixed vehicle platoon. Numerical simulation results illustrated the effectiveness of the proposed pinning control strategy.
      原文链接:
    • NSTL
    • Elsevier

    Critical specific heat of systems confined by a wall

    Borjan, Z.
    10页
    查看更多>>摘要：We analyze quantitatively the surface (excess) specific heat near criticality for semi-infinite thermodynamic systems of the Ising universality class when they are in contact with a planar wall belonging to the so-called normal surface universality class in spatial dimension d = 3 and in the mean-field limit. In order to determine the universal surface amplitudes and the spatially varying scaling functions which govern the behavior of the specific heat we use the local-functional theory. Our analysis pertains to the critical isochore, near two-phase coexistence, and along the critical isotherm if (in magnetic language) the surface and the weak bulk magnetic fields are either collinear or anti-collinear. The universal scaling functions which underly calculations of the specific heat are monotonic in most cases, except along the critical isotherm for anti-collinear bulk and surface magnetic fields. Among other results, we find in the latter case a divergent behavior of the inhomogeneous universal scaling functions associated with the surface specific heat, generated by the interface between the wall and the bulk phase of a macroscopically thick wetting film. We show that the singularity of this profile near the interface in spatial dimension three is governed by a power-law divergence with the exponent 2 alpha/beta, while it is of logarithmic nature in the mean-field limit. It turns out that this feature has a strong influence on the values of the universal surface amplitudes, regarding both their magnitude and sign. (C) 2021 Published by Elsevier B.V.
      原文链接:
    • NSTL
    • Elsevier

    The influence of average speed ratio on multilayer traffic network

    Ding, RuiZhou, TaoDu, YiMingChen, Shihui...
    11页
    查看更多>>摘要：In traffic network design, operation and management, operation speed is one of the key indicators. However, only a few studies are based on traffic dynamics on networks with the consideration of different operation speeds, and less reflected the influence of multilayer networks, which illustrate and represent different appropriate urban traffic modes. In this paper, we constructed a multilayer traffic network model with time weighted adjacency matrix. Then with the study of the influence of different network operation speed ratios on the corresponding characteristics of the comprehensive traffic network, we can clearly know that the change of network operation speed ratio will have very obvious impact on the travel time between nodes, the average travel times, the cooperation strength, the accessibility, and the network community numbers. This research has connected the rencent related study of multilayer traffic network and network operation speeds, the findings of the study afford to improve the current design and operation of traffic integrated models, and can provide some suggestions for urban and urban agglomeration development. (C)& nbsp;2022 Elsevier B.V. All rights reserved.
      原文链接:
    • NSTL
    • Elsevier

    Reducing violation behaviors of pedestrians considering group interests of travelers at signalized crosswalk

    Sun, QipengHe, ChenWang, YongjieMa, Fei...
    15页
    查看更多>>摘要：Violating traffic signals behaviors of Pedestrians are common phenomenon. How to reduce or even eliminate these dangerous behaviors has attracted deep attention from researchers and governments. This paper proposes signal control algorithm considering dual-flow (SCACDF), which prioritizes the interests of travelers groups and aims to use real-time traffic data to predict future short-term traffic conditions, redistribute the green time for pedestrians and vehicles, timely meet the traffic demand of pedestrians and reduce the probability of traffic accidents. A typical signalized crosswalk is employed as a case study. Experiments, which are implemented in AnyLogic software, are conducted to investigate the impact of the proposed algorithm under different levels of traffic demand (pedestrian demand and vehicle demand) scenarios. The results show that compared with traditional timing signal control, the proposed algorithm could reduce pedestrian violation rates and improve traffic safety in multiple scenarios. Under low vehicle density, the pedestrian violation rate dropped respectively by 28.8% and 45.3% on average when the green splits ratio is 0.5 and 0.7. Especially when the green splits ratio is relatively large, the pedestrian violation rate drops from 22.6% to 14.3% under the proposed control algorithm. In most cases, the re-segmentation of the red-man phase under the proposed algorithm could have a certain negative impact on vehicle traffic per unit time. However, when the green splits ratio is 0.5, the algorithm even improves the total traffic volume per unit time including pedestrians and passengers. In addition, the factors that affect the proposed algorithm and the optimal scope of application are also briefly discussed. (C)& nbsp;2022 Elsevier B.V. All rights reserved.
      原文链接:
    • NSTL
    • Elsevier

    Minimizing the evacuation time of a crowd from a complex building using rescue guides

    von Schantz, AntonEhtamo, Harri
    20页
    查看更多>>摘要：In an emergency situation, the evacuation of a large crowd from a complex building can become slow or even dangerous without a working evacuation plan. The use of rescue guides that lead the crowd out of the building can improve the evacuation efficiency. An important issue is how to choose the number, positions, and exit assignments of these guides to minimize the evacuation time of the crowd. Here, we model the evacuating crowd as a multi-agent system with the social force model and simple interaction rules for guides and their followers. We formulate the problem of minimizing the evacuation time using rescue guides as a stochastic optimization problem. Then, we solve it with a procedure combining numerical simulation and a genetic algorithm (GA). The GA iteratively searches for the optimal evacuation plan, while numerical simulations evaluate the evacuation time of the plans. We apply the procedure on a test case and on an evacuation of a fictional conference building. The procedure is able to solve the number of guides, their initial positions and exit assignments in a single although complicated optimization. The attained results show that the procedure converges to an optimal evacuation plan, which minimizes the evacuation time and mitigates congestion and the effect of random deviations in agents' motion. (C)& nbsp;2022 The Author(s). Published by Elsevier B.V.
      原文链接:
    • NSTL
    • Elsevier

    Growth kinetics of a single-walled carbon nanotube: Exact and simulation results

    Zounmenou, F.Hontinfinde, R. D.Hontinfinde, F.
    12页
    查看更多>>摘要：The single walled (SW) carbon nanotube (CNT), discovered in 1991, is a fascinating system for studying key processes relevant to nanomaterials synthesis. It has crucial technological applications, in particular in biomedecine, sensors and telecom networks. In this work, we study numerically the growth kinetics and surface roughness of a hexagonal SWCNT with zero chiral angle using Glauber dynamics. The SWCNT growth kinetics are described in terms of Markov processes whose states are given by its upper edge profile that we mapped onto a 5-vertex model. The model parameters considered are the supersaturation of the fluid phase or driving force and the temperature. The kinetic equation of the system is solved exactly by means of the transition matrix method for small samples and the steady state growth velocity is calculated. Kinetic Monte Carlo (KMC) simulations based on the Bortz-Kalos-Lebowitz (BKL) update algorithm are used to extract some large scale properties of the model. (c) 2022 Elsevier B.V. All rights reserved.
      原文链接:
    • NSTL
    • Elsevier