نتایج جستجو برای: transmission spectrum

تعداد نتایج: 461569  

Journal: :Electronics 2022

For the problems brought by malicious interference in unmanned aerial vehicle (UAV) swarm network, we establish a cluster-based UAV information transmission model. We mainly consider four aspects: cluster head selection, channel allocation, power allocation and position. In order to improve backhaul rate of swarm, propose joint optimization method spectrum resource with goal maximizing sum thro...

2014
K. Murali

Almost 80 to 90 percent of the radio spectrum is left unutilized at any period of time, while at the same time some other regions of spectrum experience overcrowding. We consider a dynamic spectrum access system in which Secondary Users (SUs) choose to either acquire dedicated spectrum or to use spectrum-holes (white spaces) which belong to Primary Users (PUs). The tradeoff incorporated in this...

1999
Lim Nguyen

We present a novel spread spectrum communication system for the secured transmission of digital information. The approach is based on the unconventional self-encoding principles that we have developed at the University of Nebraska for the modulation and detection of spread spectrum signals. The proposed system does not use pseudo-random codes, and is unique in that traditional transmit and rece...

2013
Wuchen Tang Muhammad Ali Imran Rahim Tafazolli

In cognitive radio network, secondary (unlicensed) users (SUs) are allowed to utilize the licensed spectrum when it is not used by the primary (licensed) users (PUs). Because of the dynamic nature of cognitive radio network, the activities of SUs such as “how long to sense” and “how long to transmit” significantly affect both the service quality of the cognitive radio networks and protection to...

1998
Lam Hui

We propose a method for recovering the shape of the mass power spectrum on large scales from the transmission fluctuations of the Lyman-alpha forest, which takes into account directly redshift-space distortions. The procedure, in discretized form, involves the inversion of a triangular matrix which projects the mass power spectrum in 3-D real-space to the transmission power spectrum in 1-D reds...

2016
Sarah Tschudin-Sutter Reno Frei Friedbert Schwahn Milanka Tomic Martin Conzelmann Anne Stranden Andreas F. Widmer

After contact precautions were discontinued, we determined nosocomial transmission of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli by screening hospital patients who shared rooms with ESBL-producing E. coli-infected or -colonized patients. Transmission rates were 2.6% and 8.8% at an acute-care and a geriatric/rehabilitation hospital, respectively. Prolonged contact was associ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی شاهرود - دانشکده کامپیوتر و فناوری اطلاعات 1391

تشخیص زنده بودن اثر انگشت، مبحثی جدید در حوزه امنیت سیستم های تشخیص هویت بر اساس اثر انگشت است. یکی از روش های تشخیص زنده بودن اثر انگشت، روش power spectrum است، که بر اساس آنـالـیـزهـای فـرکـانسی است. استفاده از این روش نتایج امیدوارکننده ای را در تشخیص حالات زنده و جعلی اثر انگشت داشته است. در این پایان نامه از این روش برای مقایسه اثر انگشت های مصنوعی sfinge با اثر انگشت های واقعی استفاده شده...

2014
Wu Peng

Based on cognitive self-organizing network transmission delay larger and larger interference to primary user receiver problem, put forward a method of spectrum joint routing selection, this method is effective to consider the transmission delay and the main user interference at the receiving end, mainly from < 1 > bandwidth available probability; < 2 > sent via link the number of bits of varian...

1998
Lam Hui

We propose a method for recovering the shape of the mass power spectrum on large scales from the transmission fluctuations of the Lyman-alpha forest, which takes into account directly redshift-space distortions. The procedure, in discretized form, involves the inversion of a triangular matrix which projects the mass power spectrum in 3-D real-space to the transmission power spectrum in 1-D reds...

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