scholarly journals Adaptive quantization for spectrum exchange information in mobile cognitive radio networks

2020 ◽  
Vol 10 (4) ◽  
pp. 3605
Author(s):  
Arief Marwanto ◽  
Sharifah Kamilah Syed Yusof ◽  
Muhammad Haikal Satria
Keyword(s):  
Adaptive Method ◽  
Signal Power ◽  
Signal Quantization ◽  
Quantization Level ◽  
Detection Failure ◽  
Uniform Quantization ◽  
Significant Difference ◽  
Adaptive Quantization ◽  
Tone Signal ◽  
Subcarrier Mapping

To reduce the detection failure of the exchanging signal power onto the OFDM subcarrier signal at uniform quantization, dynamic subcarrier mapping is applied. Moreover, to addressing low SNR’s wall-less than pre-determine threshold, non-uniform quantization or adaptive quantization for the signal quantization size parameter is proposed. μ-law is adopted for adaptive quantization subcarrier mapping which is deployed in mobility environment, such as Doppler Effect and Rayleigh Fading propagation. In this works, sensing node received signal power then sampled into a different polarity positive and negative in μ-law quantization and divided into several segmentation levels. Each segmentation levels are divided into several sub-segment has representing one tone signal subcarrier number OFDM which has the number of quantization level and the width power. The results show that by using both methods, a significant difference is obtained around 8 dB compared to those not using the adaptive method.

scholarly journals Recursive Algorithm Based on Canonical Momenta for Forward Dynamics of Multibody Systems: Numerical Results

2005 ◽  
Author(s):  
Joris Naudet ◽  
Dirk Lefeber
Keyword(s):  
Error Control ◽  
Recursive Algorithm ◽  
Equations Of Motion ◽  
Adaptive Method ◽  
Open Loop ◽  
Numerical Comparison ◽  
Hamiltonian Equations ◽  
Double Support ◽  
Dynamics Of Multibody Systems ◽  
Significant Difference

In this paper, a recursive O(n) method to obtain a set of Hamiltonian equations for open-loop and constrained multibody system is briefly discussed. The method is then used to perform a numerical comparison of acceleration based and canonical momenta based equations of motion. A relatively simple example consisting of a biped during double support phase is used for that purpose. While no significant difference in efficiency is found when using a fixed step numerical integration method, the Hamiltonian equations perform considerably better when using an adaptive method. This is at least the case when the error control is applied straightforwardly. Both methods can be made equally efficient by removing the error control on the velocities for the acceleration based equations.

scholarly journals Improvement of wireless transmission system performance for EEG signals based on development of scalar quantization

2019 ◽  
Vol 4 (1) ◽  
pp. 62-72 ◽  
Author(s):  
Mohsen Habib Nezhad ◽  
Khazaimatol S. Subari ◽  
Mehran Yahyavi
Keyword(s):  
System Performance ◽  
Transmission System ◽  
Wireless Transmission ◽  
Transmission Range ◽  
Quantization Scheme ◽  
Quantization Method ◽  
Wireless System ◽  
Quantization Level ◽  
Uniform Quantization ◽  
Wireless Eeg

Abstract Advancement of wireless technology leads to some developments in current wireless electroencephalography. Through improving the transmission method of brainwaves, it would be possible to bring more convenience for the patients in need and give this opportunity to others for discovering other aspects of the amazing brainwave. What has been proposed in this study is a new type of adjustable backward quantization method which exploits the nature of the brainwave signal. This method is based on the nature of the captured brainwave and its quantization boundary changes based on the amplitude of each EEG captured signal. The proposed quantization scheme has been analyzed with uniform and Gaussian distribution of quantization level. Consequently, the Backward Gaussian Quantization with Adjustable Boundary and two Word Memories beside the Backward Uniform Quantization with Adjustable Boundary and two Word Memories are introduced by this experiment. In addition, the performance of wireless transmission system and the proposed quantizer’s efficiency for very low frequency (up to 100 Hz) and amplitude EEG signal have been noticed. With doing so, we simulated the transmitter and receiver by MATLAB® software. To model the medium, channel was assumed as Additive White Gaussian Noise (AWGN). Meanwhile analysis is done for the whole wireless system performance in terms of transmission range, compared with current available wireless transmission systems on the market. It should be noticed that the transmission range of the proposed wireless transmission system is compared to the transmission range of current wireless EEG systems when there is no obstacle between transmitter and receiver. Furthermore, some relevant parameters to evaluate the quality of the proposed quantization method were examined. To sum up, the proposed quantization schemes show considerable performance in terms of Quantization Rate for constant MSQE and SQNR in comparison with Uniform Quantization method and the achieved transmission range of our wireless system by using this method is higher than available wireless EEG systems on market.

Results of a standardized protocol for sentinel node imaging in breast cancer with Tc-99m labeled nanocolloidal albumin

2001 ◽  
Vol 40 (03) ◽  
pp. 80-85 ◽  
Author(s):  
T. Heuser ◽  
H. Fitz ◽  
H.-J. Schroth ◽  
E. Weller ◽  
H. H. Zippel ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Lymph Nodes ◽  
Sentinel Node ◽  
Gamma Probe ◽  
Axillary Lymph Nodes ◽  
Injection Technique ◽  
Axillary Lymph ◽  
Standardized Protocol ◽  
Detection Failure ◽  
Significant Difference

Summary Aim of this study was to evaluate the results of o standardized protocol for sentinel node (SN) detection in breast cancer using Tc-99m labeled nanocolloidal albumin and a combined intra- and subdermal injection technique. Methods: One hundred and fifty-five women with proven breast cancer (disease stages Tis-T2) were included. Four injections of 10 to 15 MBq of Tc-99m nanocolloid in 0.1 ml physiologic saline were administered intra- and subdermally at the 3,6,9 and 12 o’clock positions in the skin overlying the tumor. Planar scintigraphic images in lateral and anterior projections were obtained once between 2.5 and 18 hours after tracer administration. Guided by a gamma probe, all radioactive lymph nodes in the axilla were resected, then complete dissection followed. Results: In 151 of the 155 women (97.4%), nodal tracer uptake (range 1-7 foci, average 2.2) was scinligraphically revealed. In one of these cases, drainage was only to the internal mammary lymphatic chain. Three of the 4 women with detection failure presented with histologically proven tumor infiltration of the lymphatics and axillary involvement. In 49 of the patients with visualized axillary lymph nodes (32.7%), at least one SN was metastatic. In 21 cases, this SN was the only positive node. The remaining 101 patients with negative SN included 4 cases with axillary involvement. The sensitivity of the SN with respect to the histological status of the entire axilla was thus 92.5%, the negative predictive value was 96.0%. The overall accuracy of the method was 97.3%. There was a significant difference between the number of totally detected radioactive nodes in the groups with and without nodal metastases (3.49 vs. 2.57, p <0.01). Conclusion: The described protocol represents an easy reproducible and reliable method for SN detection in breast cancer that additionally allows flexible timing of surgery. Further, we found evidence that the number of scinligraphically visualized nodes also reflects the histological status of the axilla.

Ultimate resolution and information in electron microscopy

1991 ◽  
Vol 49 ◽  
pp. 496-497
Author(s):  
D. Van Dyck
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Transfer Function ◽  
Information Transfer ◽  
Communication Channel ◽  
Structural Information ◽  
Information Rate ◽  
Noise Power ◽  
Signal Power ◽  
Imaging Device

An (electron) microscope can be considered as a communication channel that transfers structural information between an object and an observer. In electron microscopy this information is carried by electrons. According to the theory of Shannon the maximal information rate (or capacity) of a communication channel is given by C = B log2 (1 + S/N) bits/sec., where B is the band width, and S and N the average signal power, respectively noise power at the output. We will now apply to study the information transfer in an electron microscope. For simplicity we will assume the object and the image to be onedimensional (the results can straightforwardly be generalized). An imaging device can be characterized by its transfer function, which describes the magnitude with which a spatial frequency g is transferred through the device, n is the noise. Usually, the resolution of the instrument ᑭ is defined from the cut-off 1/ᑭ beyond which no spadal information is transferred.

Hearing Aid Gain Usage by Children

1989 ◽  
Vol 20 (2) ◽  
pp. 149-152 ◽  
Author(s):  
Kenneth W. Berger
Keyword(s):  
Hearing Aid ◽  
Appreciable Difference ◽  
Significant Difference ◽  
Clinically Significant

Hearing aid gain usage by two groups of children was examined. No appreciable difference was noted between the groups, nor was there a clinically significant difference between gain usage by these children as compared with a sample of adult hearing aid wearers.

A Comparison of Four Adolescent Language Tests

1987 ◽  
Vol 18 (3) ◽  
pp. 250-266 ◽  
Author(s):  
R. Jane Lieberman ◽  
Ann Marie C. Heffron ◽  
Stephanie J. West ◽  
Edward C. Hutchinson ◽  
Thomas W. Swem
Keyword(s):  
Test Performance ◽  
Sixth Grade ◽  
Significant Discrepancy ◽  
Language Impaired ◽  
Language Functions ◽  
Language Tests ◽  
Significant Difference ◽  
Sixth Grade Students ◽  
Overall Performance ◽  
Selection Of

Four recently developed adolescent language tests, the Fullerton Test for Adolescents (FLTA), the Test of Adolescent Language (TOAL), the Clinical Evaluation of Language Functions (CELF), and the Screening Test of Adolescent Language (STAL), were compared to determine: (a) whether they measured the same language skills (content) in the same way (procedures); and (b) whether students performed similarly on each of the tests. First, respective manuals were reviewed to compare selection of subtest content areas and subtest procedures. Then, each of the tests was administered according to standardized procedures to 30 unselected sixth-grade students. Despite apparent differences in test content and procedures, there was no significant difference in students' performance on three of the four tests, and correlations among test performance were moderate to high. A comparison of the pass/fail rates for overall performance on the tests, however, revealed a significant discrepancy between the proportions of students identified in need of further evaluation on the STAL (20%) and the proportion diagnosed as language impaired on the three diagnostic tests (60-73%). Clinical implications are discussed.

Auditory Selective Attention in Cerebral-Palsied Individuals

1985 ◽  
Vol 16 (4) ◽  
pp. 260-266 ◽  
Author(s):  
Lee Ann Laraway
Keyword(s):  
Selective Attention ◽  
White Noise ◽  
Normal Subjects ◽  
Auditory Selective Attention ◽  
Normal Individuals ◽  
Significant Difference

The purpose of this study was to determine whether there is a statistically significant difference between the auditory selective attention abilities of normal and cerebral-palsied individuals. Twenty-three cerebral-palsied and 23 normal subjects between the ages of 5 and 21 were asked to repeat a series of 30 items consisting of from 2 to 4 digits in the presence of intermittent white noise. Results of the study indicate that cerebral-palsied individuals perform significantly poorer than normal individuals when the stimulus is accompanied by noise. Noise was not a significant factor in the performance of the normal subjects regardless of age.

Real Ear Sound Pressure Levels Developed by Three Portable Stereo System Earphones

1992 ◽  
Vol 1 (4) ◽  
pp. 52-55 ◽  
Author(s):  
Gail L. MacLean ◽  
Andrew Stuart ◽  
Robert Stenstrom
Keyword(s):  
High Frequency ◽  
Sound Pressure ◽  
Low Frequency ◽  
Test System ◽  
Output Frequency ◽  
Frequency Effects ◽  
Adult Men ◽  
Frequency Responses ◽  
Significant Difference ◽  
Sound Pressure Levels

Differences in real ear sound pressure levels (SPLs) with three portable stereo system (PSS) earphones (supraaural [Sony Model MDR-44], semiaural [Sony Model MDR-A15L], and insert [Sony Model MDR-E225]) were investigated. Twelve adult men served as subjects. Frequency response, high frequency average (HFA) output, peak output, peak output frequency, and overall RMS output for each PSS earphone were obtained with a probe tube microphone system (Fonix 6500 Hearing Aid Test System). Results indicated a significant difference in mean RMS outputs with nonsignificant differences in mean HFA outputs, peak outputs, and peak output frequencies among PSS earphones. Differences in mean overall RMS outputs were attributed to differences in low-frequency effects that were observed among the frequency responses of the three PSS earphones. It is suggested that one cannot assume equivalent real ear SPLs, with equivalent inputs, among different styles of PSS earphones.

Speech-Language Pathologists' Perceptions of School-Based Services for Children With Hearing Loss

2020 ◽  
Vol 51 (2) ◽  
pp. 469-478
Author(s):  
Sarah Allen ◽  
Robert Mayo
Keyword(s):  
Hearing Loss ◽  
Online Survey ◽  
Working Relationships ◽  
Speech Language Pathologists ◽  
School Aged Children ◽  
School Based ◽  
Significant Difference ◽  
Positive Feelings ◽  
Children With Hearing Loss ◽  
Perceptions Of School

Purpose School-aged children with hearing loss are best served by a multidisciplinary team of professionals. The purpose of this research was to assess school-based speech-language pathologists' (SLPs) perceptions of their access to, involvement of, and working relationships with educational audiologists in their current work setting. Method An online survey was developed and distributed to school-based SLPs in North Carolina. Results A significant difference in access to and involvement of educational audiologists across the state was found. Conclusions This research contributes to professional knowledge by providing information about current perceptions in the field about interprofessional practice in a school-based setting. Overall, SLPs reported positive feelings about their working relationship with educational audiologists and feel the workload is distributed fairly.

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