Search results for "channel"
showing 10 items of 1643 documents
Unitary coupled channel analysis of theΛ(1520)resonance
2006
We study the � (1520) resonance in a coupled-channel approach involving the π� (1385) ,K� (1530), ¯ KN, and π� channels. Implementing unitarity in coupled channels, we make an analysis of the relative importance of the different mechanisms that contribute to the dynamical structure of this resonance. From experimental information on some partial wave amplitudes and constraints imposed by unitarity, we get a comprehensive description of the amplitudes and hence the couplings to the different channels. We test these amplitudes in different reactions like K − p → �π π, γp → K + K − p, γp → K + π 0 π 0 � ,a ndπ − p → K 0 K − p and find a fair
VECTOR-BARYON DYNAMICS IN γN → K0Σ REACTIONS
2014
A coupled channel model for the interaction of vector mesons with baryons is employed in the study of the γp → K0Σ+ reaction around the K*Λ and K*Σ thresholds, where the recent CBELSA/TAPS cross section shows a sudden drop and the differential cross section experiences a transition from a forward-peaked distribution to a flat one. A delicate interference between amplitudes having K*Λ and K*Σ intermediate states is found. The sharp downfall is dictated by the presence of a N* resonance produced by our model, a feature that we have employed to infer its properties. Predictions for the complementary γn → K0Σ0 reaction are also given.
Petrology and geochemistry of submarine volcanism in the Sicily Channel Rift
2006
Submarine magmatism in the Sicily Channel Rift began in the early Pliocene and lasted until almost 200 yr ago. We present here petrological and geochemical data on volcanic rocks dredged from Graham and Nameless banks and Pantelleria seamounts in the Pelagian sector of the Sicily Channel Rift. Petrological evidence suggests that the ascent of magmas to the surface was relatively rapid, probably through channels superimposed over the major tectonic discontinuities of the Rift. Major and trace element data indicate an ocean island basalt affinity for Graham and Nameless bank alkaline lavas and a depleted tholeiitic signature for one Pantelleria seamount, which had a shallower mantle source. S…
Robust Transmission for Reconfigurable Intelligent Surface Aided Millimeter Wave Vehicular Communications With Statistical CSI
2022
The integration of reconfigurable intelligent surface (RIS) into millimeter wave (mmWave) vehicular communications offers the possibility to unleash the potential of future proliferating vehicular applications. However, the high-mobility-induced rapidly varying channel state information (CSI) has been making it challenging to obtain the accurate instantaneous CSI (I-CSI) and to cope with the incurable high signaling overhead. The situation may become worse when the RIS with a large number of passive reflecting elements is deployed. To overcome this challenge, we investigate in this paper a robust transmission scheme for the time-varying RIS-aided mmWave vehicular communications, in which, s…
Tracing battery usage for second life market with a blockchain-based framework
2021
This work describes the design of a platform based on a permissioned blockchain for sharing relevant information among the actors involved in grid service provision programs. The information collected by a proprietary monitoring on-board system accessing the central unit of the Electric Vehicle, EV, is then sent to a dropbox folder owned by the car owner and then written on a blockchain platform. The platform could be supplied from similar data from the grid operator collected on the grid during the provision of services. In this way data can be validated and used for tracing the health status of the EV's battery. The design of customized smart contract allows to acquire the profiles of bat…
Low-complexity AoA and AoD Estimation in the Transformed Spatial Domain for Millimeter Wave MIMO Channels
2021
High-accuracy angle of arrival (AoA) and angle of departure (AoD) estimation is critical for cell search, stable communications and positioning in millimeter wave (mmWave) cellular systems. Moreover, the design of low-complexity AoA/AoD estimation algorithms is also of major importance in the deployment of practical systems to enable a fast and resource-efficient computation of beamforming weights. Parametric mmWave channel estimation allows to describe the channel matrix as a combination of direction-dependent signal paths, exploiting the sparse characteristics of mmWave channels. In this context, a fast Transformed Spatial Domain Channel Estimation (TSDCE) algorithm was recently proposed …
Robust Transmit Beamforming for Underlay D2D Communications on Multiple Channels
2020
Underlay device-to-device (D2D) communications lead to improvement in spectral efficiency by simultaneously allowing direct communication between the users and the existing cellular transmission. However, most works in resource allocation for D2D communication have considered single antenna transmission and with a focus on perfect channel state information (CSI). This work formulates a robust transmit beamforming design problem for maximizing the aggregate rate of all D2D pairs and cellular users (CUs). Assuming complex Gaussian distributed CSI error, our formulation guarantees probabilistically a signal to interference plus noise ratio (SINR) above a specified threshold. In addition, we al…
Reliable Underlay D2D Communications over Multiple Transmit Antenna Framework
2020
Robust beamforming is an efficient technique to guarantee the desired receiver performance in the presence of erroneous channel state information (CSI). However, the application of robust beamforming in underlay device-to-device (D2D) communication still requires further investigation. In this paper, we investigate resource allocation problem for underlay D2D communications by considering multiple antennas at the base station (BS) and at the transmitters of D2D pairs. The proposed design problem aims at maximizing the aggregate rate of all D2D pairs and cellular users (CUs) in downlink spectrum. In addition, our objective is augmented to achieve a fair allocation of resources across the D2D…
Enable concurrent transmissions with beamforming for broadband wireless access in CSMA/CA-based WLANs
2014
In CSMA/CA based wireless local networks, two stations are not allowed to transmit at the same time due to interference generated to each other, resulting in degraded throughput. Concurrent transmission, which enables simultaneous transmission of two or more stations under certain conditions, is able to overcome this problem, leading to enhanced channel utilization efficiency. Different from earlier work on this topic which focuses on omni-direction concurrent transmission, we introduce in this paper beamforming into a co-channel concurrent transmission scheme and investigate the benefits of concurrency with beamforming. The circumstances for concurrent transmission and frame scheduling are…
Experimental Observations of Flow and Bed Processes in Large-Amplitude Meandering Flume
2009
Meanders of large amplitude often exhibit asymmetric planform shape or subsidiary bends. The present work is aimed at improving on understanding of the morphodynamic phenomena affecting the bed evolution of large amplitude meandering channels. Attention is focused on the development of the steady point bar-pool configuration and of the superimposed large-scale migrating bed forms; of particular interest is the role of the changing channel curvature and bed topography variation on flow pattern. A series of experiments was carried out in a sine-generated large-amplitude meandering flume, for two values of width-to-depth ratio. Maps documenting the bed topography and the flow pattern along the…