Results 81 to 90 of about 4,923,004 (280)

OFDM aided space-time shift keying for dispersive downlink channels [PDF]

open access: yes, 2012
The performance of a Space-Time Shift Keying (STSK) scheme was shown to degrade in frequency-selective fading channels. Hence, we propose Orthogonal Frequency Division Multiplexing (OFDM) combined with STSK for frequency-selective broadband channels ...
Mohammad Ismat Kadir   +9 more
core   +1 more source

Robust connectivity in time-frequency dual fading channels for the 6G satellite IoT: chirp and FRFT

open access: yesDigital Communications and Networks
With the development of Sixth-Generation (6G) mobile communication technologies, Low Earth Orbit (LEO) satellite communication systems have become extremely important in mobile communications owing to their large coverage, high efficiency, and low cost ...
Wenliang Lin   +8 more
doaj   +1 more source

Estimation of Rice Factor Ratio for Doubly Selective Fading Channels

open access: yesIEEE Access, 2020
In wireless communication systems, Rice factor ratio (RFR) defined as K/(1 + K) is a key parameter not only to evaluate the quality of communication channel since it can reveal the severity of the small-scale fading, but also to be employed as a priori ...
Junfeng Wang   +6 more
doaj   +1 more source

Boundary‐Dependent Sleep–Wake Dysregulation in Idiopathic Hypersomnia

open access: yesAnnals of Clinical and Translational Neurology, EarlyView.
ABSTRACT Objective Idiopathic hypersomnia (IH) presents with excessive daytime sleepiness (EDS) despite apparently preserved nocturnal sleep, challenging traditional models of hypersomnolence based on sleep loss or fragmentation. We aimed to test the hypothesis that EDS in IH reflects excessive stabilization of the sleep state, consistent with ...
Samantha Mombelli   +13 more
wiley   +1 more source

Four‐Year Cognitive Outcomes in Multiple Sclerosis: Associations With Lesion Myelin Integrity

open access: yesAnnals of Clinical and Translational Neurology, EarlyView.
ABSTRACT Objectives Cognitive impairment is prevalent in patients with multiple sclerosis (MS) but whether lesion myelin integrity influences future cognitive outcomes remains unclear. We investigated the relationship between baseline lesion myelin water fraction (MWF) and cognitive performance 4 years later.
Iliana Pliska‐Bloch   +9 more
wiley   +1 more source

Observer‐Based Adaptive Event‐Triggered Tracking Control for Fuzzy TS Systems With Premise Mismatch

open access: yesInternational Journal of Adaptive Control and Signal Processing, EarlyView.
This paper presents an adaptive logistic event‐triggered observer‐based tracking controller for Takagi‐Sugeno fuzzy systems under constrained inputs and network delays. Leveraging a hybrid LMI and Secretary Bird Optimization approach, this strategy significantly minimizes communication overhead and computational burden while ensuring optimal reference ...
Oussama Djadane   +3 more
wiley   +1 more source

Influence of Scan Strategies in Electron Beam Powder Bed Fusion on Solidification, Microstructure, and High‐Temperature Compressive Properties of γ′‐Strengthened Inconel 738LC

open access: yesAdvanced Engineering Materials, EarlyView.
Experiments and thermophysical simulations were conducted to investigate the electron beam powder bed fusion electron beam (PBF‐EB/M) process for the γ′‐strengthened nickel‐based superalloy Inconel 738LC. The results demonstrate the impact of process‐induced microstructural variations on high‐temperature mechanical behavior, providing a basis for ...
Jan Niklas Petenati   +11 more
wiley   +1 more source

High‐Temperature Phase Transformation in a V‐9Si‐6.5B Alloy: The Kinetic and Crystallographic Pathway From V5SiB2 to V8SiB4

open access: yesAdvanced Engineering Materials, EarlyView.
In situ synchrotron high‐energy X‐ray diffraction reveals the real‐time high‐temperature phase evolution of a ternary V‐9Si‐6.5B alloy. The study uncovers a kinetically delayed V5SiB2 → V8SiB4 transformation governed by massive structural and chemical barriers.
Zahra Sabeti   +4 more
wiley   +1 more source

Slow Frequency-Hopping Multicarrier DS-CDMA for Transmission over Nakagami Multipath Fading Channels

open access: yes, 2001
A novel multiple access scheme based on slow frequency hopping multicarrier direct-sequence code division multiple access (SFH/MC DS-CDMA) is proposed and investigated, which can be rendered compatible with the existing second-generation narrowband CDMA ...
Yang, L-L., Hanzo, L.
core   +1 more source

Entropy‐Driven Design of Low‐Melting‐Point Alloys via Compositionally Complex Strategy

open access: yesAdvanced Engineering Materials, EarlyView.
Conventional low‐melting‐point alloys (LMPAs) are limited by a narrow compositional space and inherent property trade‐offs. This review presents an entropy‐driven design strategy that overcomes these limitations, ushering in a new class of low‐melting‐point compositionally complex alloys (LMCCAs).
Yinghui Shang   +6 more
wiley   +1 more source

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