Results 81 to 90 of about 109,670 (318)

WLAN/WDS performance using directive antennas in highly mobile scenarios: experimental results [PDF]

, 2008
This paper presents experimental results from a series of IEEE 802.11g studies to investigate the performance of vehicular to roadside wireless communications. In particular, two high-gain omni-directional antennas were used at the roadside access point,
Nix, AR, Andrew Nix, George Zaggoulos, Zaggoulos, G   +3 more
core   +1 more source

A Pilot Allocation Algorithm Based on Coalitional Game Theory for Distributed MIMO Systems

IEEE Access, 2019
With the advent of the 5G era, the number of user terminals has increased dramatically. However, the limitation of pilot resources results in pilot reuse among user terminals, which makes the performance of massive multiple-input-multiple-output (MIMO ...
Pengcheng Zhu, Jialong Bao, Lingling Zhang, Jiamin Li   +3 more
doaj   +1 more source

A Privacy-Aware Crowd Management System for Smart Cities and Smart Buildings

IEEE Access, 2020
Cities are growing at a dizzying pace and they require improved methods to manage crowded areas. Crowd management stands for the decisions and actions taken to supervise and control densely populated spaces and it involves multiple challenges, from ...
Juan Ramon Santana, Luis Sanchez, Pablo Sotres, Jorge Lanza, Tomas Llorente, Luis Munoz   +5 more
doaj   +1 more source

Single‐Layer Cholesteric Liquid Crystal Polymer Films With Visible Broadband Reflection

Advanced Optical Materials, EarlyView.
A single‐layer spin‐coated cholesteric liquid crystal polymer film exhibiting broadband reflection across the visible spectrum is demonstrated. By controlling photopolymerization‐induced pitch‐gradient formation, the film achieves low‐scattering broadband reflection, circular polarization selectivity, and compatibility with photolithographic patterning
Po‐Chun Shih, Yu‐Ming Huang, Chun‐Ting Chen, Kuan‐Wu Lin, Cheng‐Chang Li, Chun‐Ta Wang   +5 more
wiley   +1 more source

A new stochastic spatio-temporal propagation model (SSTPM) for mobile communications with antenna arrays [PDF]

, 2001
In order to evaluate the performance of third-generation mobile communication systems, radio channel models are required. The models should be capable of handling nonstationary scenarios with dynamic evolution of multipath. In this context and due to the
Piechocki, RJ, Tsoulos, G, McGeehan, JP
core   +1 more source

Lead‐Free Chiral Hybrid Metal Halides for Circularly Polarized Light‐Emitting Diodes

Advanced Optical Materials, EarlyView.
Lead‐free chiral hybrid metal halides provide a versatile platform for realizing chiroptical responses through chiral modulation of metal–halide frameworks with diverse dimensionalities, induces inversion‐symmetry breaking and enables dissymmetric excited‐state transitions toward efficient circularly polarized luminescence and electroluminescence. This
Kun Zhu, Li Wan
wiley   +1 more source

Improving the Robustness of Visual Teach‐and‐Repeat Navigation Using Drift Error Correction and Event‐Based Vision for Low‐Light Environments

Advanced Robotics Research, EarlyView.
Visual teach‐and‐repeat (VTR) navigation allows robots to learn and follow routes without building a full metric map. We show that navigation accuracy for VTR can be improved by integrating a topological map with error‐drift correction based on stereo vision.
Fuhai Ling, Ze Huang, Tony J. Prescott
wiley   +1 more source

Caps, apps and other mobile traps [PDF]

, 2013
This report outlines the major policy and legal issues on mobile phone ownership for children and young ...
Ahram Choi, Matthew Keeley, Pauline Rapaport, Janani Muhunthan   +3 more
core  

Waveguide Photoactuators: Materials, Fabrication, and Applications

Advanced Robotics Research, EarlyView.
Waveguide photoactuators convert guided light into mechanical motion. Their tethered‐flexible design enables minimally invasive surgery and confined‐space robotics. This review aims to guide materials selection, device design, and system integration, accelerating the transition of waveguide photoactuators from laboratory prototypes to versatile ...
Minjie Xi, Hemin Pan, Yang Zong, Yongfeng Mei, Jizhai Cui   +4 more
wiley   +1 more source

Photonic Time Crystals and Time‐Varying Electromagnetic Metamatter: A New Direction for Ultrafast Tunable Photonic and Microwave Materials and Devices

Advanced Science, EarlyView.
Photonic time crystals (PTCs) are systems in which electromagnetic parameters are modulated periodically in time, producing momentum bandgaps via temporal scattering rather than spatial Bragg processes. This review examines the theoretical frameworks, modeling, and computational tools for time‐varying media, and summarizes experimental demonstrations ...
Ranjan Kumar Patel, Shriram Ramanathan, Ronald P. Jenkins, Michael J. Carter   +3 more
wiley   +1 more source