MLG, we study both cases of primaries’ absence and presence.įor both cases, we define and characterize connectivity of the We show how percolation occurs in the MLG by coupling it withĪ typical discrete percolation. Multiple channels as parallel edges in a graph and build a multilayered Following the disk graph model, we represent the Show that invisibility is even more pronounced with channelĪbundance. We model this invisibility as a Poisson thinning process and Protocols, it becomes difficult for two nodes to agree on a commonĬhannel, thereby potentially remaining invisible to each other. We show that, with more channelĪbundance, even with the use of either type of rendezvous Protocols: naive ones which do not guarantee a common channelĪnd advanced ones which do. The existence of multi-channel, we use two types of rendezvous Phenomenon which we define as channel abundance. Secondary nodes have plenty of vacant channels to choose from–a In particular, we focus on the scenario where the Of Dynamic Spectrum Access networks using percolation This indicates that connectivity claims made in the literature using the geometric disc abstraction in general hold also for the more irregular shapes found in practice.Įffects of multi-channel and rendezvous protocols on the connectivity In other words, anisotropic radiation patterns and spotty coverage allow an unbounded connected component to appear at lower ENC levels than perfect circular coverage allows. We compare networks of geometric discs to other simple shapes and/or probabilistic connections, and we find that when transmission range and node density are normalized across experiments so as to preserve the expected number of connections (ENC) enjoyed by each node, discs are the “hardest ” shape to connect together. In this paper we examine how these issues affect network connectivity. In reality communication channels are unreliable and communication range is generally not rotationally symmetric. With x holes per unit cell, boron carbides have very large Seebeck coefficients that depend only weakly on x.Models of wireless ad-hoc and sensor networks are often based on the geometric disc abstraction: transmission is assumed to be isotropic, and reliable communication channels are assumed to exist (apart from interference) between nodes closer than a given distance. This strong sensitivity to composition indicates that percolation effects, arising from boron carbides having carbon atoms in inequivalent locations, influence the conductivity at low temperature. At low temperature, the boron carbide conductivities are non-Arrhenius with a temperature dependence that more » is a strong function of the composition x. Center for Excitonics (CE) Sponsoring Org.: USDOE Office of Science (SC), Basic Energy Sciences (BES) Center for Excitonics, an Energy Frontier Research Center Kwanjeong Educational Foundation National Research Foundation of Korea (NRF) OSTI Identifier: 1262288 Grant/Contract Number: SC0001088 Resource Type: Accepted Manuscript Journal Name: AIP Advances Additional Journal Information: Journal Volume: 6 Journal Issue: 4 Journal ID: ISSN 2158-3226 Publisher: American Institute of Physics (AIP) Country of Publication: United States Language: English Subject: 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY organic light emitting-diodes n-vinylcarbazole hole transport conduction threshold blends mobility systems films host hopping transport percolation charged excitons current = C icosahedra. of Technology (MIT), Cambridge, MA (United States) Energy Frontier Research Centers (EFRC) (United States). Publication Date: Fri Apr 29 00:00: Research Org.: Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States) Furthermore, the analytic relation may allow the rational design of mixed layers of small molecules for high-performance OLEDs. The relation is confirmed both numerically and experimentally through measurements of the relative conductivity of Tris(4-carbazoyl-9-ylphenyl) amine (TCTA) :1,3-bis(3,5-dipyrid-3-yl-phenyl) benzene (BmPyPb) mixtures with different concentrations, where the TCTA plays a role as hole conductor and the BmPyPb as hole insulator. We show that these two commonly-employed models are linked by an analytic expression which relates the localization length to the percolation threshold and critical exponent. Two approaches are typically used to optimize the fraction of charge transport materials in a mixed host composition: either an empirical percolative model, or a hopping transport model. Mixed host compositions that combine charge transport materials with luminescent dyes offer superior control over exciton formation and charge transport in organic light emitting devices (OLEDs).

1 hop percolation