285 research outputs found

    Traffic on complex networks: Towards understanding global statistical properties from microscopic density fluctuations

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    We study the microscopic time fluctuations of traffic load and the global statistical properties of a dense traffic of particles on scale-free cyclic graphs. For a wide range of driving rates R the traffic is stationary and the load time series exhibits antipersistence due to the regulatory role of the superstructure associated with two hub nodes in the network. We discuss how the superstructure affects the functioning of the network at high traffic density and at the jamming threshold. The degree of correlations systematically decreases with increasing traffic density and eventually disappears when approaching a jamming density Rc. Already before jamming we observe qualitative changes in the global network-load distributions and the particle queuing times. These changes are related to the occurrence of temporary crises in which the network-load increases dramatically, and then slowly falls back to a value characterizing free flow

    Disorder-induced critical behavior in driven diffusive systems

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    Using dynamic renormalization group we study the transport in driven diffusive systems in the presence of quenched random drift velocity with long-range correlations along the transport direction. In dimensions d<4d\mathopen< 4 we find fixed points representing novel universality classes of disorder-dominated self-organized criticality, and a continuous phase transition at a critical variance of disorder. Numerical values of the scaling exponents characterizing the distributions of relaxation clusters are in good agreement with the exponents measured in natural river networks

    Elliptic curves with torsion group Z/6Z\Z /6\Z

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    We exhibit several families of elliptic curves with torsion group isomorphic to Z/6Z \Z/6\Z and generic rank at least 33. Families of this kind have been constructed previously by several authors: Lecacheux, Kihara, Eroshkin and Woo. We mention the details of some of them and we add other examples developed more recently by Dujella and Peral, and MacLeod. Then we apply an algorithm of Gusi\'c and Tadi\'c and we find the exact rank over \Q(t) to be 3 and we also determine free generators of the Mordell-Weil group for each family. By suitable specializations, we obtain the known and new examples of curves over \Q with torsion Z/6Z \Z/6\Z and rank 88, which is the current record

    Scaling of avalanche queues in directed dissipative sandpiles

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    We simulate queues of activity in a directed sandpile automaton in 1+1 dimensions by adding grains at the top row with driving rate 0<r10 < r \leq 1. The duration of elementary avalanches is exactly described by the distribution P1(t)t3/2exp(1/Lc)P_1(t) \sim t^{-3/2}\exp{(-1/L_c)}, limited either by the system size or by dissipation at defects Lc=min(L,ξ)L_c= \min (L,\xi). Recognizing the probability P1P_1 as a distribution of service time of jobs arriving at a server with frequency rr, the model represents a new example of the server queue in the queue theory. We study numerically and analytically the tail behavior of the distributions of busy periods and energy dissipated in the queue and the probability of an infinite queue as a function of driving rate.Comment: 11 pages, 9 figures; To appear in Phys. Rev.

    On unitarizability in the case of classical p-adic groups

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    In the introduction of this paper we discuss a possible approach to the unitarizability problem for classical p-adic groups. In this paper we give some very limited support that such approach is not without chance. In a forthcoming paper we shall give additional evidence in generalized cuspidal rank (up to) three.Comment: This paper is a merged and revised version of ealier preprints arXiv:1701.07658 and arXiv:1701.07662. The paper is going to appear in the Proceedings of the Simons Symposium on Geometric Aspects of the Trace Formul

    Global Jacquet-Langlands correspondence, multiplicity one and classification of automorphic representations

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    In this paper we show a local Jacquet-Langlands correspondence for all unitary irreducible representations. We prove the global Jacquet-Langlands correspondence in characteristic zero. As consequences we obtain the multiplicity one and strong multiplicity one theorems for inner forms of GL(n) as well as a classification of the residual spectrum and automorphic representations in analogy with results proved by Moeglin-Waldspurger and Jacquet-Shalika for GL(n).Comment: 49 pages; Appendix by N. Grba

    The effect of bandwidth in scale-free network traffic

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    We model information traffic on scale-free networks by introducing the bandwidth as the delivering ability of links. We focus on the effects of bandwidth on the packet delivering ability of the traffic system to better understand traffic dynamic in real network systems. Such ability can be measured by a phase transition from free flow to congestion. Two cases of node capacity C are considered, i.e., C=constant and C is proportional to the node's degree. We figured out the decrease of the handling ability of the system together with the movement of the optimal local routing coefficient αc\alpha_c, induced by the restriction of bandwidth. Interestingly, for low bandwidth, the same optimal value of αc\alpha_c emerges for both cases of node capacity. We investigate the number of packets of each node in the free flow state and provide analytical explanations for the optimal value of αc\alpha_c. Average packets traveling time is also studied. Our study may be useful for evaluating the overall efficiency of networked traffic systems, and for allevating traffic jam in such systems.Comment: 6 pages, 4 figure

    Orientation of the fifteenth and sixteenth century mosques in the former Yugoslavia

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    The paper presents the analysis of the orientation of 60 mosques built in the XV and XVI centuries in the Balkans' region of former Yugoslavia. The mosques have been selected according to their architectural value - mostly the dome mosques that were built by the most renowned builders. Based on the geographic coordinates, the qiblas of all mosques were calculated and the azimuths of their axes measured on orthophotographs. Statistical analysis has shown that the axes of these mosques vary in the horizon sector that is five times wider than the calculated sector of the correct qibla, with a systematic deviation of -10 degrees 15' in relation to the correct qibla. Connections between deviations of the architectural design (dome mosques and other mosques), location and elevation have not been identified. However, a connection between deviations and the time of construction has been identified: deviations from the qibla are smaller in mosques built at a later date. The paper has laid the groundwork for future analysis of the causes of the aforementioned deviations: in the XV and XVI centuries there were no accurate geographic coordinates of locations and the builders were not able to calculate (take over, measure) the exact qibla direction, regardless of the method they applied

    Avalanches in complex spin networks

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    We investigate the magnetization reversal processes on classes of complex spin networks with antiferromagnetic interaction along the network links. With slow field ramping the hysteresis loop and avalanches of spin flips occur due to topological inhomogeneity of the network, even without any disorder of the magnetic interaction [B. Tadic, et al., Phys. Rev. Lett. 94 (2005) 137204]. Here we study in detail properties of the magnetization avalanches, hysteresis curves and density of domain walls and show how they can be related to the structural inhomogeneity of the network. The probability distribution of the avalanche size, N_s(s), displays the power-law behaviour for small s, i.e. N_s(s)\propto s^{-\alpha}. For the scale-free networks, grown with preferential attachment, \alpha increases with the connectivity parameter M from 1.38 for M=1 (trees) to 1.52 for M=25. For the exponential networks, \alpha is close to 1.0 in the whole range of M.Comment: 16 pages, 10 figures in 29 eps file
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