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Raghunathan, S.B. (author), Schouten, H.F. (author), Visser, T.D. (author)We demonstrate that coherence vortices, singularities of the correlation function, generally occur in partially coherent electromagnetic beams. In successive cross sections of Gaussian Schell-model beams, their locus is found to be a closed string. These coherence singularities have implications for both interference experiments and correlation...journal article 2012
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Li, C. (author), Van de Bovenkamp, R. (author), Van Mieghem, P.F.A. (author)We introduce the ?-susceptible-infected-susceptible (SIS) spreading model, which is taken as a benchmark for the comparison between the N-intertwined approximation and the Pastor-Satorras and Vespignani heterogeneous mean-field (HMF) approximation of the SIS model. The N-intertwined approximation, the HMF approximation, and the ?-SIS spreading...journal article 2012
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Van Mieghem, P.F.A. (author), Cator, E. (author)Since the Susceptible-Infected-Susceptible (SIS) epidemic threshold is not precisely defined in spite of its practical importance, the classical SIS epidemic process has been generalized to the ??SIS model, where a node possesses a self-infection rate ?, in addition to a link infection rate ? and a curing rate ?. The exact Markov equations are...journal article 2012
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Raghunathan, S.B. (author), Gan, C.H. (author), Van Dijk, T. (author), Ea Kim, B. (author), Schouten, H.F. (author), Ubachs, W. (author), Lalanne, P. (author), Visser, T.D. (author)We report a plasmon steering method that enables us to dynamically control the direction of surface plasmons generated by a two-mode slit in a thin metal film. By varying the phase between different coherent beams that are incident on the slit, individual waveguide modes are excited. Different linear combinations of the two modes lead to...journal article 2012
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Trajanovski, S. (author), Scellato, S. (author), Leontiadis, I. (author)The study of real-world communication systems via complex network models has greatly expanded our understanding on how information flows, even in completely decentralized architectures such as mobile wireless networks. Nonetheless, static network models cannot capture the time-varying aspects and, therefore, various temporal metrics have been...journal article 2012
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Pang, X. (author), Fischer, D.G. (author), Visser, T.D. (author)The Gouy phase, sometimes called the phase anomaly, is the remarkable effect that in the region of focus a converging wave field undergoes a rapid phase change by an amount of ?, compared to the phase of a plane wave of the same frequency. This phenomenon plays a crucial role in any application where fields are focused, such as optical coherence...journal article 2012
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Di Girolamo, P. (author), Summa, D. (author), Cacciani, M. (author), Norton, E.G. (author), Peters, G. (author), Dufournet, Y. (author)Multi-wavelength lidar measurements in the melting layer revealing the presence of dark and bright bands have been performed by the University of BASILicata Raman lidar system (BASIL) during a stratiform rain event. Simultaneously radar measurements have been also performed from the same site by the University of Hamburg cloud radar MIRA 36 (35...journal article 2012
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Lian, X. (author), Nikookar, H. (author), Ligthart, L.P. (author)Cognitive radio (CR) is an intelligent radio system and is able to share the spectrum with licensed users (LU). By adopting adaptive beam forming techniques, CR can reuse the spectrum with LU via directing main beams towards CR users while displaying nulls towards LU. In this article, we present a new distributed beam forming (DB) technique, and...journal article 2012
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Van Genderen, P. (author), Krasnov, O.A. (author), Wang, Z. (author), Tigrek, R.F. (author)Retrieval of cloud parameters in weather radar benefits from polarimetric measurements. Most polarimetric radars measure the full backscatter matrix (BSM) using a few alternating polarized sounding signals. Using specially encoded orthogonal frequency division multiplexing (OFDM) signals however, the BSM can be measured in a single simultaneous...journal article 2012
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Ge, X. (author), Wang, H. (author)Many networks are characterized by the presence of communities, densely intra-connected groups with sparser inter-connections between groups. We propose a community overlay network representation to capture large-scale properties of communities. A community overlay Go can be constructed upon a network G, called the underlying network, by (a)...journal article 2012
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Lu, H. (author), Xu, T. (author), Nikookar, H. (author), Ligthart, L.P. (author)In this paper, we investigate the diversity, capacity and complexity issues of cooperative Zero-Padding (ZP)-Orthogonal FrequencyDivisionMultiplexing (OFDM) communication. We consider cooperative ZP-OFDM communication over a multipath Rayleigh channel and with multiple Carrier Frequency Offsets (CFOs) existing at different relays. We use a...journal article 2011
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Van Mieghem, P.F.A. (author), Blenn, N. (author), Doerr, C. (author)We analyse the number of votes, called the digg value, which measures the impact or popularity of submitted information in the Online Social Network Digg. Experiments over five years indicate that the digg value of a story on the first frontpage follows closely a lognormal distribution. While the law of proportionate effect explains lognormal...journal article 2011
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Van Mieghem, P.F.A. (author)Serious epidemics, both in cyber space as well as in our real world, are expected to occur with high probability, which justifies investigations in virus spread models in (contact) networks. The N-intertwined virus spread model of the SIS-type is introduced as a promising and analytically tractablemodel of which the steady-state behavior is...journal article 2011
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Van Kester, S. (author), Xiao, T. (author), Kooij, R.E. (author), Brunnstrom, K. (author), Ahmed, O.K. (author)This paper studies the impact of freezing of video on quality as experienced by users. Two types of freezes are investigated. First a freeze where the image pauses, so no frames were lost (frame halt). In the second type of freeze, the image freezes and skips that part of the video (frame drop). Measuring Mean Opinion Score (MOS) was done by...journal article 2011
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Lian, X. (author), Nikookar, H. (author), Ligthart, L.P. (author)In this paper, we introduce Adaptive Beamforming (AB) and Distributed Beamforming (DB) as two efficient techniques for IntelligentWiMAX (I-WiMAX). I-WiMAX is a new maritime communication system, consisting of Smart Radio (SR) principles and mobile WiMAX based on the IEEE 802.16e standard. Adopting AB, the same spectrum can accommodate more users...journal article 2011
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Li, C. (author), Wang, H. (author), De Haan, W. (author), Stam, C.J. (author), Van Mieghem, P.F.A. (author)An increasing number of network metrics have been applied in network analysis. If metric relations were known better, we could more effectively characterize networks by a small set of metrics to discover the association between network properties/metrics and network functioning. In this paper, we investigate the linear correlation coefficients...journal article 2011
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Dufournet, Y. (author), Russchenberg, H.W.J. (author)Radar-based retrievals are often employed to characterize the microphysical properties of cloud hydrometeors, i.e. their phases, habits, densities as well as their respective size and orientation distributions. These techniques are based on a synergetic use of different cloud observation sensor(s) and microphysical model(s) where the information...journal article 2011
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- Wang, H. (author), Winterbach, W. (author), Van Mieghem, P.F.A. (author) journal article 2011
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Caratelli, D. (author), Gielis, J. (author), Natalini, P. (author), Ricci, P.E. (author), Tavkhelidze, I. (author)The interior and exterior Robin problems for the Helmholtz equation in starlike planar domains are addressed by using a suitable Fourier-like technique. Attention is in particular focused on normal-polar domains whose boundaries are defined by the so-called “superformula” introduced by J. Gielis. A dedicated numerical procedure based on the...journal article 2011
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Caratelli, D. (author), Viganó, M.C. (author)A novel analytical approach to the synthesis of linear sparse arrays with uniform?amplitude excitation is presented and thoroughly discussed in this paper. The proposed technique, based on the auxiliary array factor concept, is aimed at the deterministic determination of the optimal array element density and excitation phase tapering...journal article 2011