scholarly journals Structure of the emission field of ensemble of ultra-wideband chaotic sources

2019 ◽  
Vol 30 ◽  
pp. 05029 ◽  
Author(s):  
Yuri Andreyev
Keyword(s):  
Power Density ◽  
Ultra Wideband ◽  
Emission Pattern ◽  
Reception Point ◽  
Emission Mode ◽  
The Individual ◽  
Collective Emission ◽  
The Waves ◽  
Independent Individual ◽  
Entire Ensemble

The structure of the emission field of ensemble of independent ultra-wideband chaotic sources in collective emission mode is investigated analytically and numerically, including power density, directivity, and far zone border. The waves emitted by independent individual sources are incoherent; hence in the reception point the created incoherent fields are summed by power, and this summation gives no additional directivity to the ensemble emission pattern. If all the individual antennas are equal, emission pattern of the entire ensemble is the same as the emission pattern of any of the individual emitters.

scholarly journals Individual Alpha Peak Frequency, an Important Biomarker for Live Z-Score Training Neurofeedback in Adolescents with Learning Disabilities

2021 ◽  
Vol 11 (2) ◽  
pp. 167
Author(s):  
Rubén Pérez-Elvira ◽  
Javier Oltra-Cucarella ◽  
José Antonio Carrobles ◽  
Minodora Teodoru ◽  
Ciprian Bacila ◽  
...  
Keyword(s):  
Learning Disabilities ◽  
Pediatric Population ◽  
Peak Frequency ◽  
Normative Values ◽  
Z Score ◽  
Absolute Power ◽  
The Individual ◽  
And Behavior ◽  
The Waves ◽  
Alpha Peak

Learning disabilities (LDs) have an estimated prevalence between 5% and 9% in the pediatric population and are associated with difficulties in reading, arithmetic, and writing. Previous electroencephalography (EEG) research has reported a lag in alpha-band development in specific LD phenotypes, which seems to offer a possible explanation for differences in EEG maturation. In this study, 40 adolescents aged 10–15 years with LDs underwent 10 sessions of Live Z-Score Training Neurofeedback (LZT-NF) Training to improve their cognition and behavior. Based on the individual alpha peak frequency (i-APF) values from the spectrogram, a group with normal i-APF (ni-APF) and a group with low i-APF (li-APF) were compared in a pre-and-post-LZT-NF intervention. There were no statistical differences in age, gender, or the distribution of LDs between the groups. The li-APF group showed a higher theta absolute power in P4 (p = 0.016) at baseline and higher Hi-Beta absolute power in F3 (p = 0.007) post-treatment compared with the ni-APF group. In both groups, extreme waves (absolute Z-score of ≥1.5) were more likely to move toward the normative values, with better results in the ni-APF group. Conversely, the waves within the normal range at baseline were more likely to move out of the range after treatment in the li-APF group. Our results provide evidence of a viable biomarker for identifying optimal responders for the LZT-NF technique based on the i-APF metric reflecting the patient’s neurophysiological individuality.

scholarly journals Compact Liquid Crystal Based Tunable Band-Stop Filter with an Ultra-Wide Stopband by Using Wave Interference Technique

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Longzhu Cai ◽  
Huan Xu ◽  
Daping Chu
Keyword(s):  
Liquid Crystal ◽  
Impedance Matching ◽  
Wide Frequency Range ◽  
Ultra Wideband ◽  
New Wave ◽  
Wave Interference ◽  
Rejection Level ◽  
Band Stop Filter ◽  
The Individual ◽  
Uwb Applications

A wave interference filtering section that consists of three stubs of different lengths, each with an individual stopband of its own central frequency, is reported here for the design of band-stop filters (BSFs) with ultra-wide and sharp stopbands as well as large attenuation characteristics. The superposition of the individual stopbands provides the coverage over an ultra-wide frequency range. Equations and guidelines are presented for the application of a new wave interference technique to adjust the rejection level and width of its stopband. Based on that, an electrically tunable ultra-wide stopband BSF using a liquid crystal (LC) material for ultra-wideband (UWB) applications is designed. Careful treatment of the bent stubs, including impedance matching of the main microstrip line and bent stubs together with that of the SMA connectors and impedance adaptors, was carried out for the compactness and minimum insertion and reflection losses. The experimental results of the fabricated device agree very well with that of the simulation. The centre rejection frequency as measured can be tuned between 4.434 and 4.814 GHz when a biased voltage of 0–20 Vrms is used. The 3 dB and 25 dB stopband bandwidths were 4.86 GHz and 2.51 GHz, respectively, which are larger than that of other recently reported LC based tunable BSFs.

scholarly journals A Transactional, Whole-School Approach to Resilience

2021 ◽  
pp. 220-231
Author(s):  
Carmel Cefai
Keyword(s):  
Research Evidence ◽  
Social Contexts ◽  
Ecological Perspective ◽  
Educational Systems ◽  
Multiple Systems ◽  
Whole School ◽  
Resilience Framework ◽  
Whole School Approach ◽  
The Individual ◽  
The Waves

In contrast to the earlier understandings of resilience for the select, invulnerable few, an ecological perspective provides the opportunity for all children to develop resilience given resilience-enhancing, protective social contexts. In this chapter, the author explores a transactional-ecological perspective of resilience in the context of educational systems, underlining the limitations of an overreliance on the individual in resilience building. The chapter presents a transactional, whole-school, resilience framework for educational systems informed by the research evidence, focusing on both curricular competence-building and contextual processes across multiple systems. The chapter concludes with an illustration of a recent resilience program, RESCUR Surfing the Waves, informed by this approach.

scholarly journals A Rectangular Notch-Band UWB Antenna with Controllable Notched Bandwidth and Centre Frequency

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 777 ◽  
Author(s):  
Anees Abbas ◽  
Niamat Hussain ◽  
Min-Joo Jeong ◽  
Jiwoong Park ◽  
Kook Sun Shin ◽  
...  
Keyword(s):  
Satellite Communication ◽  
Ultra Wideband ◽  
Center Frequency ◽  
Area Network ◽  
Electromagnetic Bandgap ◽  
Uwb Antenna ◽  
Compact Antenna ◽  
Notch Band ◽  
The Individual ◽  
Rectangular Notch

This paper presents the design and realization of a compact ultra-wideband (UWB) antenna with a rectangular notch wireless area network (WLAN) band that has controllable notched bandwidth and center frequency. The UWB characteristics of the antenna are achieved by truncating the lower ends of the rectangular microstrip patch, and the notch characteristics are obtained by using electromagnetic bandgap (EBG) structures. EBGs consist of two rectangular metallic conductors loaded on the back of the radiator, which is connected to the patch by shorting pins. A rectangular notch at the WLAN band with high selectivity is realized by tuning the individual resonant frequencies of the EBGs and merging them. Furthermore, the results show that the bandwidth and frequency of the rectangular notch band could be controlled according to the on-demand rejection band applications. In the demonstration, the rectangular notch band was shifted to X-band satellite communication by tuning the EBG parameters. The simulated and measured results show that the proposed antenna has an operational bandwidth from 3.1–12.5 GHz for |S11| < -10 with a rectangular notch band from 5–6 GHz, thus rejecting WLAN band signals. The antenna also has additional advantages: the overall size of the compact antenna is 16 × 25 × 1.52 mm3 and it has stable gain and radiation patterns.

Comparative studies on MWCNTs, Fe2O3 and Fe2O3/MWCNTs thin films towards supercapacitor application

2016 ◽  
Vol 40 (3) ◽  
pp. 2619-2627 ◽  
Author(s):  
Shrikant S. Raut ◽  
Babasaheb R. Sankapal
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Energy Density ◽  
Specific Capacitance ◽  
Power Density ◽  
Comparative Studies ◽  
Hybrid Thin Film ◽  
Supercapacitor Application ◽  
Electrochemical Supercapacitor ◽  
The Individual

Fe2O3/MWCNTs hybrid thin film exhibits superior electrochemical supercapacitor behaviour in terms of specific capacitance, energy density and power density than the individual Fe2O3 and MWCNTs thin films.

scholarly journals Alternation of the flickering morphology between the high and low state in MV Lyrae

2020 ◽  
Vol 641 ◽  
pp. A55
Author(s):  
A. Dobrotka ◽  
H. Negoro ◽  
P. Konopka
Keyword(s):  
Light Curve ◽  
Power Density ◽  
Cataclysmic Variables ◽  
X Rays ◽  
Low Frequencies ◽  
Characteristic Frequencies ◽  
Outer Disk ◽  
Frequency Components ◽  
The Individual ◽  
X Ray Binaries

Aims. We studied unique data of the nova-like system MV Lyr taken by the Kepler space telescope during its transition from the high to low state and vice versa. We were interested in the evolution of frequency components found previously in different data also obtained by Kepler. Methods. We divided the light curve into ten-day segments and investigated the corresponding power density spectra. We searched for individual frequency components by fitting with Lorentzian functions. Additionally, we investigated the variability using averaged shot profiles calculated from the light curve divided into ten equally spaced subsamples. Results. We found very complex changes in the power density spectra. We focused our study onto three frequency components. A significant increase in activity is seen at low frequencies. Contrariwise, the high frequency part of the spectrum strongly decreases in power with a specific rise in characteristic frequencies of the individual components. We discuss various scenarios of this phenomenology such as the reprocessing of X-rays in a receding accretion disk or radiation from a more active region at the outer disk. Finally, we show that various cataclysmic variables show similar characteristic frequencies in their power density spectra. These are dependent on activity stage, making the situation similar to X-ray binaries.

scholarly journals Trial-by-Trial Discrimination of Three Enantiomer Pairs by Neural Ensembles in Mammalian Olfactory Bulb

2006 ◽  
Vol 95 (3) ◽  
pp. 1369-1379 ◽  
Author(s):  
M. J. Lehmkuhle ◽  
R. A. Normann ◽  
E. M. Maynard
Keyword(s):  
Olfactory Bulb ◽  
Single Trial ◽  
Activation Patterns ◽  
Neural Ensembles ◽  
Spatially Distributed ◽  
Receptor Neurons ◽  
Output Neurons ◽  
The Individual ◽  
Multielectrode Recording ◽  
Entire Ensemble

Populations of output neurons in the mammalian olfactory bulb (OB) exhibit distinct, widespread spatial and temporal activation patterns when stimulated with odorants. However, questions remain as to how ensembles of mitral/tufted (M/T) neurons in the mammalian OB represent odorant information. In this report, the single-trial encoding limits of random ensembles of putative single- and multiunit M/T cells in the anesthetized rat OB during presentations of enantiomers of limonene, carvone, and 2-butanol are investigated using simultaneous multielectrode recording techniques. The results of these experiments are: the individual constituents of our recorded ensembles broadly represent information about the presented odorants, the ensemble single-trial response of small spatially distributed populations of M/T neurons can readily discriminate between six different odorants, and the most consistent odorant discrimination is attained when the ensemble consists of all available units and their responses are integrated over an entire breathing cycle. These results suggest that small differences in spike counts among the ensemble members become significant when taken within the context of the entire ensemble. This may explain how ensembles of broadly tuned OB neurons contribute to olfactory perception and may explain how small numbers of individual units receiving input from distinct olfactory receptor neurons can be combined to form a robust representation of odorants.

scholarly journals Human Respiration Localization Method Using UWB Linear Antenna Array

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Yuan Liu ◽  
Shiyou Wu ◽  
Jie Chen ◽  
Guangyou Fang ◽  
Hejun Yin
Keyword(s):  
Antenna Array ◽  
Vital Sign ◽  
Ultra Wideband ◽  
Linear Antenna ◽  
Angle Of Arrival ◽  
Localization Method ◽  
Linear Antenna Array ◽  
Human Respiration ◽  
Simulation And Experiment ◽  
The Individual

Human respiration is the basic vital sign in remote monitoring. There has been remarkable progress in this area, but some challenges still remain to obtain the angle-of-arrival (AOA) and distinguish the individual signals. This paper presents a 2D noncontact human respiration localization method using Ultra-Wideband (UWB) 1D linear antenna array. The imaging reconstruction based on beamforming is used to estimate the AOA of the human chest. The distance-slow time 2D matrix at the estimated AOA is processed to obtain the distance and respiration frequency of the vital sign. The proposed method can be used to isolate signals from individual targets when more than one human object is located in the surveillance space. The feasibility of the proposed method is demonstrated via the simulation and experiment results.

scholarly journals Magnetically coupled atmosphere, fast sausage MHD waves, and forced magnetic field reconnection during the SOL2014-09-10T17:45 flare

2020 ◽  
Vol 643 ◽  
pp. A140
Author(s):  
H. Mészárosová ◽  
P. Gömöry
Keyword(s):  
Magnetic Field ◽  
Solar Corona ◽  
Solar Atmosphere ◽  
Extreme Ultraviolet ◽  
Free Field ◽  
Mhd Waves ◽  
Field Energy ◽  
Plasma Flows ◽  
The Individual ◽  
The Waves

Aims. We study the physical properties and behaviour of the solar atmosphere during the GOES X1.6 solar flare on 2014 September 10. Methods. The steady plasma flows and the fast sausage MHD waves were analysed with the wavelet separation method. The magnetically coupled atmosphere and the forced magnetic field reconnection were studied with the help of the Vertical-Current Approximation Non-linear Force-Free Field code. Results. We studied a mechanism of MHD wave transfer from the photosphere without dissipation or reflection before reaching the corona and a mechanism of the wave energy distribution over the solar corona. We report a common behaviour of (extreme)ultraviolet steady plasma flows (speed of 15.3 → 10.9 km s−1) and fast sausage MHD waves (Alfvén speed of 13.7 → 10.3 km s−1 and characteristic periods of 1587 → 1607 s), propagating in cylindrical plasma waveguides of the individual atmospheric layers (photosphere → corona) observed by SDO/AIA/HMI and IRIS space instruments. A magnetically coupled solar atmosphere by a magnetic field flux tube above a sunspot umbra and a magnetic field reconnection forced by the waves were analysed. The solar seismology with trapped, leakage, and tunnelled modes of the waves, dissipating especially in the solar corona, is discussed with respect to its possible contribution to the outer atmosphere heating. Conclusions. We demonstrate that a dispersive nature of fast sausage MHD waves, which can easily generate the leaky and other modes propagating outside of their waveguide, and magnetic field flux tubes connecting the individual atmospheric layers can distribute the magnetic field energy across the active region. This mechanism can contribute to the coronal energy balance and to our knowledge on how the coronal heating is maintained.

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