Results 41 to 50 of about 2,288 (244)

Cyclostationary Feature Detection Based on Compressed Sensing and Wavelet De-Noising

Dianxin kexue, 2015
To improve the vacant spectrum utilization，ultra-wideband spectrum sensing is critical for cognitive radio （CR）as it enables secondary users to dynamically access the unoccupied spectrum bands.However，the fast and accurate spectrum sensing is still a ...
Haifeng Tan, Jun Lu, Xuan Fu, Qixun Zhang   +3 more
doaj   +2 more sources

Chiral Phase Change Nanomaterials

Advanced Functional Materials, EarlyView.
This work demonstrates reversible, non‐volatile phase transitions in chiral Ge2${\rm Ge}_2$Sb2${\rm Sb}_2$Te5${\rm Te}_5$ (GST) nanohelices for high‐speed optical modulation of chirality and dynamic control of the state of polarization (SOP). The chiral nanostructures are fabricated using a highly directional, wafer‐scale physical vapor deposition ...
Joshua A. Burrow, Md Shah Alam, Riad Yahiaoui, Evan M. Smith, Ryan Laing, Jules Gardener, Thomas A. Searles, Piyush J. Shah, Shivashankar Vangala, Joshua R. Hendrickson, Andrew M. Sarangan, Imad Agha   +11 more
wiley   +1 more source

From Photoalignment to Structured Light: Liquid Crystal Platforms for Beam Shaping and Complex Wavefronts

Advanced Functional Materials, EarlyView.
Photoaligned and photopatterned liquid crystal platforms provide programmable control of optical phase, polarization, and spin‐orbit interactions, enabling compact generation of structured light and complex wavefronts. This review highlights how tailored molecular orientations transform simple beams into designed optical fields, opening versatile ...
Le Zhou, Tingjun Zhong, Sijie Liu, Pouya Nosratkhah, Ke Xu, Yuzhen Zhao, Kristiaan Neyts   +6 more
wiley   +1 more source

Cooperative Spectrum Sensing Algorithm Based on CS-SLIM Iterative Minimization Sparse Learning

International Journal of Distributed Sensor Networks, 2013
Dynamic spectrum management is a key technology in cognitive wireless sensor network (C-WSN), in which spectrum sensing plays an important role. In this paper, we propose an improved approach as sparse learning via iterative minimization based on ...
Ning Cao, Xiaowen Hu, Hao Lu, Minghe Mao
doaj   +1 more source

Enhanced compressive wideband frequency spectrum sensing for dynamic spectrum access [PDF]

EURASIP Journal on Advances in Signal Processing, 2012
Wideband spectrum sensing detects the unused spectrum holes for dynamic spectrum access (DSA). Too high sampling rate is the main problem. Compressive sensing (CS) can reconstruct sparse signal with much fewer randomized samples than Nyquist sampling with high probability.
Yipeng Liu 0001, Qun Wan
openaire   +2 more sources

Magnesium‐Based Transient Bioelectronics, Bio‐Optics and Bio‐Scaffolds

Advanced Functional Materials, EarlyView.
This paper reviews the state of the art and recent advances in magnesium‐based thin‐film, foils, and scaffolds for applications in transient bio‐optics, bioelectronics and tissue engineering. The design principles, fabrication methods, material properties, and integration strategies are discussed in detail.
Massimo Mariello, Yves Leterrier
wiley   +1 more source

Extraordinary n‐type Tellurium‐Free Thermoelectric Performance of Y‐Doped BiSe via Synergistic Effect of Vacancies and Band Engineering

Advanced Functional Materials, EarlyView.
Yttrium doping in Sb‐alloyed BiSe synergistically induces Bi vacancies and flattens conduction bands, simultaneously slashing lattice thermal conductivity by 50% and boosting the power factor. The optimized n‐type Bi0.64Sb0.3Y0.06Se delivers a peak zT of 0.91 at 393 K (average zT 0.76, 300–523 K) and an 8‐pair module with 4.6% conversion efficiency ...
Wenhao Xie, Fang Lyu, Xiaolong Sun, Chang Li, Xiaolu Zhu, Liangwei Hu, Qianfeng Ding, Wenjie Zhou, Muyang Huang, Yineng Gou, Yi Zhao, Han Tang, Wei Cao, Yue Hou, Yun Zheng, Ady Suwardi, Ziyu Wang   +16 more
wiley   +1 more source

Least entropy based randomized strategy for wideband spectrum sensing with cooperation

Tongxin xuebao, 2010
To study the strategy for wideband spectrum sensing in cognitive radio system,the relation between the accuracy of channel state estimation and entropy was analyzed from the perspective of information entropy.And then a least entropy based randomized ...
MAI Lei-xin, QIN Xiao-wei, DAI Xu-chu
doaj   +2 more sources

Polarization Sensitivity of Chiral Manganese Halide Scintillators Enables High‐Resolution X‐Ray Imaging

Advanced Functional Materials, EarlyView.
Highly luminescent chiral manganese halide crystals are synthesized using chiral ligands, and they exhibit dissymmetry factors up to 1.4 × 10−2 and show X‐ray detection scintillation capability with a light yield of 43 380 photons/MeV and a low detection limit of 0.05198 µGyair·s−1.
Yue Han, Jun'an Lai, Peng He, Wenxia Zhang, Xirong Ke, Shengsi Liu, Kang An, Xiao‐Fang Jiang, Lakshminarayana Polavarapu, Xiaosheng Tang   +9 more
wiley   +1 more source

Compressive sensing based maximum-minimum subband energy detection for cognitive radios

Heliyon, 2020
To satisfy the growing spectrum demands of emerging wireless applications, cognitive radios have been considered as a viable option. It enables dynamic spectrum access opportunistically using wideband spectrum sensing (WSS) methods to discover the ...
Desalegn T. Dagne, Kinde A. Fante, Getachew A. Desta   +2 more
doaj   +1 more source