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J. M. Kumpula J. Saramäki K. Kaski J. Kertész 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,56(1):41-45
According to Fortunato and Barthélemy, modularity-based community detection
algorithms have a resolution threshold such that small communities in a large
network are invisible. Here we generalize their work and show that the q-state
Potts community detection method introduced by Reichardt and Bornholdt
also has a resolution threshold. The model contains a parameter by which this threshold can be tuned, but no a priori principle
is known to select the proper value.
Single global optimization criteria do not seem capable for detecting all
communities if their size distribution is broad. 相似文献
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Juuso Sammaljärvi Antero Lindberg Mikko Voutilainen Jussi Ikonen Marja Siitari-Kauppi Petteri Pitkänen Lasse Koskinen 《Journal of Radioanalytical and Nuclear Chemistry》2017,314(3):1557-1575
The purpose of this work was to support the long-term experiments for investigation of rock matrix retention properties at the spent nuclear fuel repository site ONKALO, in Olkiluoto, Western Finland. Towards this end, rock samples were characterised in terms of porosity connected to mineralogy, with emphasis on pore sizes, and fillings. Both filled and unfilled pores were found with unfilled pores being majority in the pegmatitic granite veins of the mostly veined gneiss samples. It was found that the fillings were often connected to local alteration and the alteration caused variation in the range of pore sizes. 相似文献
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Recently pattern formation in layered structures, showing complicated superimposed patterns, has been modeled by coupling two Turing systems linearly, i.e., passively, such that the characteristic length scales of the independent systems are well separated. Here we propose a model of two non-linearly coupled Turing systems to study pattern formation in layered membrane-like structures, where the coupling plays an active role and changes the kinetics of the uncoupled systems. Extensive numerical simulations show that non-linear coupling generates a number of new regular patterns different from the ones observed earlier with linearly coupled systems. Some of them turn out to be superimposed patterns with different length scales, but many are not. Also, contrary to the linear coupling case, the strength of the non-linear coupling is found to play an important role in the formation and selection of patterns. 相似文献
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Petteri Kaski Patric R.J. Östergård Olli Pottonen 《Journal of Combinatorial Theory, Series A》2006,113(8):1764-1770
The Steiner quadruple systems of order 16 are classified up to isomorphism by means of an exhaustive computer search. The number of isomorphism classes of such designs is 1,054,163. Properties of the designs—including the orders of the automorphism groups and the structures of the derived Steiner triple systems of order 15—are tabulated. A consistency check based on double counting is carried out to gain confidence in the correctness of the classification. 相似文献
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In this paper we introduce a storage process with singular continuous input. The input process is defined as the local time of a stationary reflecting Brownian motion with drift. Many basic charateristics of the process are computed explicitly, e.g., stationary distribution, distributions of the starting and ending time of on-going busy and idle periods. We also consider the multifractal spectrum of the input process and observe that it is independent of system parameters. 相似文献
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