ACQUISITION OF SARSAT INFORMATION USING AN AUTO-CORRELATION BASED ADAPTIVE LINE ENHANCER

2005 ◽  
Vol 02 (04) ◽  
pp. 291-302
Author(s):  
S. E. EL-KHAMY ◽  
M. M. HADHOUD ◽  
M. I. DESSOUKY ◽  
B. M. SALAM ◽  
F. E. ABD EL-SAMIE
Keyword(s):  
Autocorrelation Function ◽  
Spectral Estimation ◽  
Comparison Study ◽  
Noisy Signal ◽  
New Approach ◽  
Auto Correlation ◽  
Fixed Pole ◽  
Adaptive Line Enhancer ◽  
Emergency Locator ◽  
Emergency Locator Transmitter

This paper develops a new approach to the detection of the emergency locator transmitter (ELT) signal using an adaptive line enhancer (ALE). The input signal to the ALE is replaced by its autocorrelation function (ACF) because noise affects the central samples of the autocorrelation function only while it affects all samples of the noisy signal. This gives the ALE the ability to get rid of noise, easily. The output ACF is then used in the spectral estimation and detection of the ELT signal. This approach is related to the signal processing using Higher Order Statistics (HOS) since the ACF is the used input. The paper also compares the results of the new approach to other different previously used methods foe ELT signal detection. The first method uses the signal xk as an input to the ALE, and the second method uses [Formula: see text]. Results illustrate the superiority of the proposed method over the other two methods. A comparison study between the performance of two types of ALE; Fixed pole radius and variable pole radius ALEs in detecting the ELT signal, is introduced.

scholarly journals Evaluating dynamic bivariate correlations in resting-state fMRI: A comparison study and a new approach

NeuroImage ◽  
2014 ◽  
Vol 101 ◽  
pp. 531-546 ◽  
Author(s):  
Martin A. Lindquist ◽  
Yuting Xu ◽  
Mary Beth Nebel ◽  
Brain S. Caffo
Keyword(s):  
Resting State ◽  
Resting State Fmri ◽  
Comparison Study ◽  
New Approach

Alternative Environmental Contours for Marine Structural Design: A Comparison Study

2014 ◽  
Author(s):  
Erik Vanem ◽  
Elzbieta M. Bitner-Gregersen
Keyword(s):  
Structural Design ◽  
Joint Distribution ◽  
Traditional Approach ◽  
Physical Space ◽  
Probability Density Functions ◽  
Density Functions ◽  
Comparison Study ◽  
New Approach ◽  
Contour Lines ◽  
Wind Sea

A new approach to estimating environmental contours has recently been proposed, where the contours are estimated in the original physical space by Monte Carlo simulations from the joint distribution directly rather than applying the Rosenblatt transformation. In this paper, the new and the traditional approach to estimating the contours are presented and the assumptions on which they are based are discussed. The different results given by these two methods are then compared in a number of case studies. Simultaneous probability density functions are fitted to the joint distribution of significant wave height and wave period for selected ocean locations and, for each area, environmental contours are estimated for both methods. The chosen locations are characterised by different wave climates. Thus, the practical consequences of the choice of approach are assessed. Particular attention is given to mixed sea systems, i.e. a combination of wind sea and swell. In these situations, the new approach for environmental contours may fail to identify realistic conditions along some parts of the contours while for other wave conditions the contours are quite similar. The paper also briefly discusses possible ways of amending the new approach to estimating the contours to obtain more realistic conditions all along the contour lines.

scholarly journals Penerima Sinyal Emergency Locator Transmitter dengan Metode Direct Receiver pada Frekuensi 121,5 MHz

2020 ◽  
Vol 12 (1) ◽  
pp. 17-23
Author(s):  
Rustamaji Rustamaji ◽  
Kania Sawitri ◽  
Arief Shubhan Hakim
Keyword(s):  
Audio Signal ◽  
Signal Beam ◽  
Search And Rescue ◽  
Civil Aviation ◽  
Rf Amplifier ◽  
Audio Amplifier ◽  
Rf Devices ◽  
Emergency Locator ◽  
Emergency Locator Transmitter ◽  
Aircraft Accident

To find out the location of an aircraft accident from an ELT signal beam of 121.5 MHz, search and rescue (SAR) officers or civil aviation authorities need an ELT signal receiver device that works at the same frequency, which is 121.5 MHz. The purpose of this research is to produce an ELT signal receiver with direct receiver method at a frequency of 121.5 MHz which is simpler, requires fewer RF devices, and is according to specifications for civil aviation. In this research, the design and realization of ELT signal receivers are carried out using the direct receiver method, including: a BPF and a RF amplifier as a direct receiver circuit, an AM demodulator, and an audio amplifier. Based on the results of measurements and tests that have been done, the direct receiver circuit can receive an ELT signal at a frequency of 121.5 MHz in the range of 121.330 to 121.617 MHz with -40.35 dB sensitivity, the AM demodulator can demodulate the audio signal at a frequency of 346.6 Hz, and the audio signal at a frequency of 337.6 Hz as a pointer to an ELT signal can be heard through the loudspeaker. The results of this study are ELT signal receivers with direct receiver method at a frequency of 121.5 MHz which are according to specifications for civil aviation.

scholarly journals A Comparison Study of Copula Models for European Financial Index Returns

2017 ◽  
Vol 9 (10) ◽  
pp. 155
Author(s):  
Paula V. Tofoli ◽  
Flavio A. Ziegelmann ◽  
Osvaldo Candido
Keyword(s):  
Subprime Crisis ◽  
Time Varying ◽  
Comparison Study ◽  
Markov Switching Model ◽  
Copula Models ◽  
New Approach ◽  
Switching Model ◽  
Long Period ◽  
Financial Index ◽  
Over Time

In this paper, we introduce a new approach to modeling dependence between international financial returns over time, combining time-varying copulas and the Markov switching model. We apply these copula models and also those proposed by Patton (2006), Jondeau and Rockinger (2006) and Silva Filho, Ziegelmann, and Dueker (2012) to the return data of the FTSE-100, CAC-40 and DAX indexes. We are particularly interested in comparing these methodologies in terms of the resulting dynamics of dependence and the models’ abilities to forecast possible capital losses. Because risks related to extreme events are important for risk management, we compare and select the models based on VaR forecasts. Interestingly, all the models identify a long period of high dependence between the returns beginning in 2007, when the subprime crisis was evolving. Surprisingly, the elliptical copulas perform best in forecasting the extreme quantiles of the portfolios returns.

Hardware-Based Framework of Photonic Reservoir Computing with Coupled SOAs Network

2018 ◽  
Vol 0 (0) ◽  
Author(s):  
Louiza Dehyadegari ◽  
Mohammad Reza Salehi ◽  
Maryam Sedigh Sarvestani ◽  
Ebrahim Abiri
Keyword(s):  
Time Series ◽  
Random Sequence ◽  
Reservoir Computing ◽  
Time Series Classification ◽  
Noisy Signal ◽  
Photonic Structure ◽  
New Approach ◽  
Triangular Wave ◽  
Wave Forms ◽  
One Step

AbstractIn this paper, a photonic structure for reservoir computing is presented. A new approach for photonic reservoir computing is proposed using a network of SOAs arranged in a waterfall topology and coupled by semi-transparent mirrors. The proposed method is then simulated in OptiSystem software. As this software is hardware framework-based, the simulation result is one step closer to fabrication than the previous works. A series of noisy and noise-free time-series signals are employed to evaluate the performance of the proposed method. The used time-series signals contain random sequence of both square and triangular wave forms. The results of this simulation show 92.14% recognition of a noise-free signal and 79.32% of a 60 dB noisy signal. The parameters of the simulated photonic reservoir network are also optimized to achieve higher accuracy in this time-series classification.

scholarly journals Fundamental Frequency Extraction of Noisy Speech Signals

2015 ◽  
Vol 43 ◽  
pp. 51-61
Author(s):  
Mirza A.F.M. Rashidul Hasan ◽  
Rubaiyat Yasmin ◽  
Dipankar Das ◽  
M. M. Hoque ◽  
M. I. Pramanik ◽  
...  
Keyword(s):  
Fundamental Frequency ◽  
Autocorrelation Function ◽  
Time Domain ◽  
Speech Signals ◽  
Original Signal ◽  
New Approach ◽  
Noisy Speech ◽  
Frequency Detection ◽  
Comparative Results

In this paper, we proposed a correlation based method which is a new approach using the autocorrelation function is weighted by the reciprocal of the YIN and very useful for accurate fundamental frequency extraction. The autocorrelation function and also YIN is a popular measurement in estimating fundamental frequency in time domain. In our proposed method, instead of the original signal, we employ its center clipping signal for obtaining the autocorrelation function and this function is weighted by the reciprocal of the YIN for fundamental frequency detection. Comparative results on female and male voices in white and exhibition noise shows that the proposed method can detect fundamental frequency with better accuracy in terms of gross pitch errors as compared to other related methods.

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