Allocation Scheme of Short Training Sequence Based on OFDM-PON

2014 ◽  
Vol 989-994 ◽  
pp. 1695-1699
Author(s):  
Song Lin Guo ◽  
Xi Chen ◽  
Chao Xing Xu ◽  
Yuan Jiang ◽  
Ying Chun Li
Keyword(s):  
Time Domain ◽  
Wireless Lan ◽  
Training Sequence ◽  
Experimental Results ◽  
Subcarrier Allocation ◽  
Allocation Scheme ◽  
Improved Method ◽  
Symbol Synchronization ◽  
Time Domain Data ◽  
The Mean

A new structure of short training sequence for symbol synchronization in OFDM-PON system is proposed in this paper. By adjusting the subcarrier allocation scheme of short training sequence in a wireless LAN, it makes the mean of short training sequence signal in time domain from non-zero to zero mean and solves the receiving data demodulation interference caused by the wrong trail of the non-zero mean short training sequence in time-domain. Data demodulation simulation and experimental results show that the improved method can effectively reduce the training sequence interference errors caused by tailing.

An Improved Symbol Synchronization Method in OFDM Systems Based on Training Sequence

2015 ◽  
Vol 713-715 ◽  
pp. 1273-1276
Author(s):  
Chen Ding
Keyword(s):  
Training Sequence ◽  
Ofdm Systems ◽  
Improved Method ◽  
Symbol Synchronization ◽  
Synchronization Method ◽  
Simulation Results

Aim at the high request of symbol synchronization in OFDM systems and the defects of classical methods, an improved method is given, which designs the new structure of training sequence and selects better TDD-offset. Simulation results show that when this method is used, the timing metric curve has only one peak, the symbol synchronization is more accurate.

SERUM TRIIODOTHYRONINE DETERMINATION BY SATURATION ANALYSIS

1973 ◽  
Vol 72 (4) ◽  
pp. 714-726 ◽  
Author(s):  
A. Burger ◽  
B. Miller ◽  
C. Sakoloff ◽  
M. B. Vallotton
Keyword(s):  
Ionic Strength ◽  
Limit Of Detection ◽  
Improved Method ◽  
Accuracy Of Measurement ◽  
Tracer Amount ◽  
The Mean ◽  
Physiological Values ◽  
Hyperthyroid Patients ◽  
Solvent Blank

ABSTRACT An improved method for the determination of serum triiodothyronine (T3) has been developed. After addition of a tracer amount of the hormone, T3 was extracted from 1 ml serum under conditions of pH and ionic strength which favoured T3 extraction (89%) over thyroxine (T4) extraction (58%). Chromatography of the extracted material on Sephadex LH-20 separated T3 completely from residual T4. The T3 eluate was dried, then re-dissolved in 0.5 ml NaOH 0.04 n. To 0.2 ml duplicate aliquots, a standard amount of TBG was added for the competitive protein analysis. After one hour incubation at 4°C, separation of bound from free T3 was achieved on small Sephadex G-25 columns. Overall recovery was 67 ± 10.8% and correction for the loss was made. The solvent blank was 37 ± 27 (sd) ng/100 ml. Accuracy of measurement of known quantities of T3 added to serum was 98.4%. The coefficient of variation within the assay was 6.2% and between the assays it was 11.4%. The limit of detection (0.1 ng) corresponded to a concentration of 25 ng/100 ml. T4 added to serum did not interfere with T3 determination until high non-physiological values were reached. The mean ± sd serum T3 in 54 euthyroid subjects was 153 ± 58 ng/100 ml and in 24 hyperthyroid patients it was 428 ±186 ng/100 ml; 4 out of the 24 hyperthyroid values were within 2 sd of the mean euthyroid group. All the values found in the euthyroid group were well above the limit of detection of the method.

JOINT INTERPRETATION OF AIRBORNE ELECTROMAGNETIC DATA IN THE TIME DOMAIN AND FREQUENCY DOMAIN

2018 ◽  
Vol 12 (7-8) ◽  
pp. 76-83
Author(s):  
E. V. KARSHAKOV ◽  
J. MOILANEN
Keyword(s):  
Fourier Transform ◽  
Frequency Domain ◽  
Time Domain ◽  
Frequency Interval ◽  
Single Spectrum ◽  
Simultaneous Inversion ◽  
Homogeneous Half Space ◽  
Time Domain Data ◽  
The Time Domain

Тhe advantage of combine processing of frequency domain and time domain data provided by the EQUATOR system is discussed. The heliborne complex has a towed transmitter, and, raised above it on the same cable a towed receiver. The excitation signal contains both pulsed and harmonic components. In fact, there are two independent transmitters operate in the system: one of them is a normal pulsed domain transmitter, with a half-sinusoidal pulse and a small "cut" on the falling edge, and the other one is a classical frequency domain transmitter at several specially selected frequencies. The received signal is first processed to a direct Fourier transform with high Q-factor detection at all significant frequencies. After that, in the spectral region, operations of converting the spectra of two sounding signals to a single spectrum of an ideal transmitter are performed. Than we do an inverse Fourier transform and return to the time domain. The detection of spectral components is done at a frequency band of several Hz, the receiver has the ability to perfectly suppress all sorts of extra-band noise. The detection bandwidth is several dozen times less the frequency interval between the harmonics, it turns out thatto achieve the same measurement quality of ground response without using out-of-band suppression you need several dozen times higher moment of airborne transmitting system. The data obtained from the model of a homogeneous half-space, a two-layered model, and a model of a horizontally layered medium is considered. A time-domain data makes it easier to detect a conductor in a relative insulator at greater depths. The data in the frequency domain gives more detailed information about subsurface. These conclusions are illustrated by the example of processing the survey data of the Republic of Rwanda in 2017. The simultaneous inversion of data in frequency domain and time domain can significantly improve the quality of interpretation.

Advanced Fault Isolation Technique Using Electro-Optical Terahertz Pulse Reflectometry (EOTPR) for 2D and 2.5D Flip-Chip Package

2012 ◽  
Author(s):  
Lihong Cao ◽  
Manasa Venkata ◽  
Meng Yeow Tay ◽  
Wen Qiu ◽  
J. Alton ◽  
...  
Keyword(s):  
Time Domain ◽  
Flip Chip ◽  
Time Domain Reflectometry ◽  
Fault Isolation ◽  
Experimental Results ◽  
Terahertz Pulse ◽  
Isolation And Identification ◽  
Isolation Technique ◽  
Non Destructive

Abstract Electro-optical terahertz pulse reflectometry (EOTPR) was introduced last year to isolate faults in advanced IC packages. The EOTPR system provides 10μm accuracy that can be used to non-destructively localize a package-level failure. In this paper, an EOTPR system is used for non-destructive fault isolation and identification for both 2D and 2.5D with TSV structure of flip-chip packages. The experimental results demonstrate higher accuracy of the EOTPR system in determining the distance to defect compared to the traditional time-domain reflectometry (TDR) systems.

scholarly journals Prediction of shallow bit position based on vibration signal monitoring of bit broken rock

2021 ◽  
Vol 17 (1) ◽  
pp. 155014772199170
Author(s):  
Jinping Yu ◽  
Deyong Zou
Keyword(s):  
Acoustic Emission ◽  
Time Domain ◽  
Vibration Signal ◽  
Rock Breaking ◽  
Drill String ◽  
Mean Square ◽  
Drilling Force ◽  
Emission Signal ◽  
Force Signal ◽  
The Mean

The speed of drilling has a great relationship with the rock breaking efficiency of the bit. Based on the above background, the purpose of this article is to predict the position of shallow bit based on the vibration signal monitoring of bit broken rock. In this article, first, the mechanical research of drill string is carried out; the basic changes of the main mechanical parameters such as the axial force, torque, and bending moment of drill string are clarified; and the dynamic equilibrium equation theory of drill string system is analyzed. According to the similarity criterion, the corresponding relationship between drilling process parameters and laboratory test conditions is determined. Then, the position monitoring test system of the vibration bit is established. The acoustic emission signal and the drilling force signal of the different positions of the bit in the process of vibration rock breaking are collected synchronously by the acoustic emission sensor and the piezoelectric force sensor. Then, the denoised acoustic emission signal and drilling force signal are analyzed and processed. The mean value, variance, and mean square value of the signal are calculated in the time domain. The power spectrum of the signal is analyzed in the frequency domain. The signal is decomposed by wavelet in the time and frequency domains, and the wavelet energy coefficients of each frequency band are extracted. Through the wavelet energy coefficient calculated by the model, combined with the mean, variance, and mean square error of time-domain signal, the position of shallow buried bit can be analyzed and predicted. Finally, by fitting the results of indoor experiment and simulation experiment, it can be seen that the stress–strain curve of rock failure is basically the same, and the error is about 3.5%, which verifies the accuracy of the model.

Rigorous time-domain analysis of statistically oriented graphene sheet fluctuations

2017 ◽  
Vol 36 (5) ◽  
pp. 1351-1363 ◽  
Author(s):  
Athanasios N. Papadimopoulos ◽  
Stamatios A. Amanatiadis ◽  
Nikolaos V. Kantartzis ◽  
Theodoros T. Zygiridis ◽  
Theodoros D. Tsiboukis
Keyword(s):  
Monte Carlo ◽  
Standard Deviation ◽  
Finite Difference ◽  
Surface Waves ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Mean Value ◽  
Content Type ◽  
The Mean ◽  
Difference Time

Purpose Important statistical variations are likely to appear in the propagation of surface plasmon polariton waves atop the surface of graphene sheets, degrading the expected performance of real-life THz applications. This paper aims to introduce an efficient numerical algorithm that is able to accurately and rapidly predict the influence of material-based uncertainties for diverse graphene configurations. Design/methodology/approach Initially, the surface conductivity of graphene is described at the far infrared spectrum and the uncertainties of its main parameters, namely, the chemical potential and the relaxation time, on the propagation properties of the surface waves are investigated, unveiling a considerable impact. Furthermore, the demanding two-dimensional material is numerically modeled as a surface boundary through a frequency-dependent finite-difference time-domain scheme, while a robust stochastic realization is accordingly developed. Findings The mean value and standard deviation of the propagating surface waves are extracted through a single-pass simulation in contrast to the laborious Monte Carlo technique, proving the accomplished high efficiency. Moreover, numerical results, including graphene’s surface current density and electric field distribution, indicate the notable precision, stability and convergence of the new graphene-based stochastic time-domain method in terms of the mean value and the order of magnitude of the standard deviation. Originality/value The combined uncertainties of the main parameters in graphene layers are modeled through a high-performance stochastic numerical algorithm, based on the finite-difference time-domain method. The significant accuracy of the numerical results, compared to the cumbersome Monte Carlo analysis, renders the featured technique a flexible computational tool that is able to enhance the design of graphene THz devices due to the uncertainty prediction.

scholarly journals End-to-End Data Rate Performance of Decode-and-Forward Relaying with Different Resource Allocation Schemes

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Inam Ullah ◽  
Alexis Dowhuszko ◽  
Zhong Zheng ◽  
David González González ◽  
Jyri Hämäläinen
Keyword(s):  
Resource Allocation ◽  
Closed Form ◽  
Data Rate ◽  
Allocation Scheme ◽  
Optimal Resource Allocation ◽  
Decode And Forward ◽  
Optimal Resource ◽  
The Mean ◽  
Resource Allocation Scheme ◽  
Resource Allocation Schemes

This paper studies the end-to-end (e2e) data rate of dual-hop Decode-and-Forward (DF) infrastructure relaying under different resource allocation schemes. In this context, we first provide a comparative analysis of the optimal resource allocation scheme with respect to several other approaches in order to provide insights into the system behavior and show the benefits of each alternative. Then, assuming the optimal resource allocation, a closed form expression for the distribution of the mean and outage data rates is derived. It turns out that the corresponding mean e2e data rate formula attains an expression in terms of an integral that does not admit a closed form solution. Therefore, a tight lower bound formula for the mean e2e data rate is presented. Results can be used to select the most convenient resource allocation scheme and perform link dimensioning in the network planning phase, showing the explicit relationships that exist between component link bandwidths, SNR values, and mean data rate.

scholarly journals Contour Detection for Fibre of Preserved Szechuan Pickle Based on Dilated Convolution

2019 ◽  
Vol 9 (13) ◽  
pp. 2684 ◽  
Author(s):  
Hongyang Li ◽  
Lizhuang Liu ◽  
Zhenqi Han ◽  
Dan Zhao
Keyword(s):  
Edge Detection ◽  
State Of The Art ◽  
Contour Detection ◽  
Experimental Results ◽  
Contour Method ◽  
Class Differences ◽  
Dilated Convolution ◽  
The Mean ◽  
Art Performance

Peeling fibre is an indispensable process in the production of preserved Szechuan pickle, the accuracy of which can significantly influence the quality of the products, and thus the contour method of fibre detection, as a core algorithm of the automatic peeling device, is studied. The fibre contour is a kind of non-salient contour, characterized by big intra-class differences and small inter-class differences, meaning that the feature of the contour is not discriminative. The method called dilated-holistically-nested edge detection (Dilated-HED) is proposed to detect the fibre contour, which is built based on the HED network and dilated convolution. The experimental results for our dataset show that the Pixel Accuracy (PA) is 99.52% and the Mean Intersection over Union (MIoU) is 49.99%, achieving state-of-the-art performance.

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