Impact of the Time Window Length on the Ship Trajectory Reconstruction Based on AIS Data Clustering

2021 ◽  
pp. 25-36
Author(s):  
Marta Mieczyńska ◽  
Ireneusz Czarnowski
Keyword(s):  
Data Clustering ◽  
Time Window ◽  
Window Length ◽  
Trajectory Reconstruction

Adaptive time-window length based on online performance measurement in SSVEP-based BCIs

2015 ◽  
Vol 149 ◽  
pp. 93-99 ◽  
Author(s):  
Janir Nuno da Cruz ◽  
Feng Wan ◽  
Chi Man Wong ◽  
Teng Cao
Keyword(s):  
Performance Measurement ◽  
Time Window ◽  
Window Length ◽  
Adaptive Time

scholarly journals A study of acoustic characteristics of voluntary expiratory sounds produced before and immediately after swallowing

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Shoma Hattori ◽  
Shinji Nozue ◽  
Yoshiaki Ihara ◽  
Koji Takahashi
Keyword(s):  
Fourier Transform ◽  
Fast Fourier Transform ◽  
Time Window ◽  
Maximum Amplitude ◽  
Comparison Method ◽  
Window Length ◽  
Acoustic Characteristics ◽  
The Mean ◽  
Time Waveform ◽  
The Relationship

AbstractTo evaluate the expiratory sounds produced during swallowing recorded simultaneously with videofluorographic examination of swallowing (VF) using fast Fourier transform (FFT), and to examine the relationship between dysphagia and its acoustic characteristics. A total of 348 samples of expiratory sounds were collected from 61 patients with dysphagia whose expiratory sounds were recorded during VF. The VF results were evaluated by one dentist and categorized into three groups: safe group (SG), penetration group (PG), and aspiration group (AG). The duration and maximum amplitude of expiratory sounds produced were measured as the domain characteristics on the time waveform of these sounds and compared among the groups. Time window-length appropriate for FFT and acoustic discriminate values (AD values) of SG, PG, and AG were also investigated. The groups were analyzed using analysis of variance and Scheffé's multiple comparison method. The maximum amplitude of SG was significantly smaller than those of PG and AG. The mean duration in SG (2.05 s) was significantly longer than those in PG (0.84 s) and AG (0.96 s). The AD value in SG was significantly lower than those in PG and AG. AD value detects penetration or aspiration, and can be useful in screening for dysphagia.

A first arrival picking method of microseismic data based on single time window with window length independent

2018 ◽  
Vol 22 (6) ◽  
pp. 1613-1627
Author(s):  
Tong Shen ◽  
Xianguo Tuo ◽  
Huailiang Li ◽  
Yong Liu ◽  
Wenzheng Rong
Keyword(s):  
Time Window ◽  
Window Length ◽  
Single Time ◽  
Microseismic Data ◽  
First Arrival

Source characteristics of small to moderate earthquakes in the Kanto region, Japan: application of a new definition of the S-wave time window length

1996 ◽  
Vol 86 (5) ◽  
pp. 1284-1291
Author(s):  
Kazutoshi Watanabe ◽  
Haruo Sato ◽  
Shigeo Kinoshita ◽  
Masakazu Ohtake
Keyword(s):  
Wave Energy ◽  
Seismic Moment ◽  
Time Window ◽  
P Wave ◽  
Corner Frequency ◽  
Window Length ◽  
S Wave ◽  
S Waves ◽  
Source Characteristics ◽  
Kanto Region

Abstract The S wave from a local earthquake generally consists of several pulses, in contrast to a simple pulse of P wave. This results in a large uncertainty in the estimation of seismic moment and wave energy when the window length for S-wave analysis is not chosen properly. In this study, we propose a new method to define objectively an appropriate time window length of the S wave for estimation of source characteristics based on the S-wave to P-wave energy ratio for a point shear dislocation source. Analyzing waveform data of 97 local earthquakes in the Kanto region, Japan, whose magnitudes M range from 3.3 to 6.0, we obtained simple equations for predicting the time window length of the S-wave TS as a function of earthquake magnitude or pulse width of P-wave TP; we got TS ≈ 1.8 TP for the relation between TP and TS. Applying the S-wave window thus defined, we estimated seismic energy E, seismic moment M0, and corner frequency fc for both P and S waves. Regression analysis of those parameters revealed (1) our method to define TS is confirmed by the fact that the seismic moment determined from P and S waves are consistent; (2) in the range of 1014 < M0 < 1018 (N·m), M0 is almost proportional to f−3c both for P and S waves; (3) the value of E/M0 is 2.7 ∼ 4.0 × 10−5; and (4) breakdown of the scaling relation is seen at M ≦ 4.

The attenuation of coda waves in the RIF area.

2020 ◽  
Author(s):  
Oussama Arab ◽  
mimoun harnafi ◽  
Ibrahim ouchen ◽  
roumaissae azguet ◽  
younes El Fellah ◽  
...  
Keyword(s):  
Quality Factor ◽  
Time Window ◽  
Coda Waves ◽  
Window Length ◽  
Quality Factors ◽  
Average Value ◽  
Local Earthquakes ◽  
The World ◽  
Single Backscattering Model

<p>This work is presenting the attenuation of coda waves in the Rif region. Using 15 broadband stations, we investigate the attenuation of coda waves utilizing the single backscattering model of aki and chouet. We collect 70 local earthquakes during 2014 for five laps time window 20, 30, 40, 50 and 60s. We computed the quality factors at different central frequencies band on which start from 1.5, 3.0, 6.0, 9.0, 12.0 and 18.0 Hz. For 40s window length, the Qc gives average value for the whole zone of about 128,51 for 1.5 Hz and 993,44 for 18 Hz band frequencies. We observed a clear dependency between the quality factor and the frequency. Also, we have found that this region is tectonic active comparing to previous studies around the world.</p>

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