Effective analysis technique of unstable acoustic signature from ship radiated noise

2001 ◽  
Vol 109 (5) ◽  
pp. 2296-2297
Author(s):  
Jong‐rak Yoon ◽  
Yong‐ju Ro ◽  
Jae‐Jin Chun
2014 ◽  
Vol 1049-1050 ◽  
pp. 1577-1580
Author(s):  
Cheng Jun Hu ◽  
Yuan Zheng ◽  
Han Bo Zhao

Periodic signal is abundant in ship radiated noise. Its detection is an important step towards active control of ship’s acoustic signature. Based on power spectrum analysis and DEMON analysis, an approach to detect line spectrum and modulation spectrum of ship radiated noise is proposed. Periodogram method is used for power spectrum estimation. The separation of line and continuous spectrum, false positive removal, and line spectrum merging are conducted to improve the quality of detected characteristic line spectrum. Via DEMON analysis, steady physical characteristics including propeller’s rotational speed and number of blades are obtained. Finally, the effectiveness of the approach is demonstrated by simulation results.


2021 ◽  
Author(s):  
Esen Cintosun ◽  
Layton Gilroy

The acoustic signature of an Orca-class training vessel (Patrol Craft Training, PCT) Moose from the Royal Canadian Navy (RCN) was measured at the RCN’s Patricia Bay acoustic range on Vancouver Island, British Columbia, Canada. The acoustic range trials included accelerometer measurements on the ship hull and in the engine room and hydrophone measurements at approximately 100 m from the ship. The trials were carried out at the ship speed range of 3 to 20 knots. The test data from all the trial runs was used to derive, evaluate and validate the method of estimating ship underwater radiated noise from onboard vibrations. In the investigation, the runs were split into two sets: a training set and a testing set. A least squares approximation, AQV (average quadratic velocity) SL (source level) correlation, was then applied to the training set data to formulate a transfer function to estimate the underwater radiated noise from onboard vibrations. The AQV is calculated from accelerometer measurements (vibration levels) and SL is obtained from the hydrophone measurements. The third octave frequency band (from 10 Hz to 10 kHz) SL estimations of the testing set runs (using the transfer function and AQV) are within 1 to 3 dB of SL from the hydrophone measurements. This study demonstrates a capability of monitoring underwater radiated noise from ships using only onboard vibration levels which may be of interest for future projects relating to the reduction of shipping noise against a threshold in acoustically sensitive environments.


2020 ◽  
Vol 49 (11) ◽  
pp. 1137-1157 ◽  
Author(s):  
Athanasios Agalianos ◽  
Max Sieber ◽  
Ioannis Anastasopoulos

Author(s):  
W. M. Kriven

Significant progress towards a fundamental understanding of transformation toughening in composite zirconia ceramics was made possible by the application of a TEM contrast analysis technique for imaging elastic strains. Spherical zirconia particles dispersed in a large-grained alumina matrix were examined by 1 MeV HVEM to simulate bulk conditions. A thermal contraction mismatch arose on cooling from the processing temperature of 1500°C to RT. Tetragonal ZrO2 contracted amisotropically with α(ct) = 16 X 10-6/°C and α(at) = 11 X 10-6/°C and faster than Al2O3 which contracted relatively isotropically at α = 8 X 10-6/°C. A volume increase of +4.9% accompanied the transformation to monoclinic symmetry at room temperature. The elastic strain field surrounding a particle before transformation was 3-dimensionally correlated with the internal crystallographic orientation of the particle and with the strain field after transformation. The aim of this paper is to theoretically and experimentally describe this technique using the ZrO2 as an example and thereby to illustrate the experimental requirements Tor such an analysis in other systems.


2020 ◽  
Vol 3 (2) ◽  
pp. 140-153
Author(s):  
Resti Fadhilah Nurrohmah ◽  
Radia Purbayati

The purpose of this study was to study the level of Islamic financial literacy and public confidence in the interest in saving in Islamic banks. The variables in this study are the level of Islamic financial literacy (X1), public trust (X2), and interest in saving (Y).The method of this study is descriptive quantitative approach. The data source of this study are primary data obtained by distributing questionnaires. Respondents taken are residents in the city of Bandung, with samples domiciled in the city of Bandung and at least 17 years old. The data analysis technique uses multiple linear regression analysis. The results showed that the variable level of islamic financial literacy and public trust has positive effect in the interest in saving in Islamic banks. The findings in this study provide a reference to Islamic banks, the level of literacy and public trust regarding interest in saving, therefore Islamic banks must socialize to the public.


2019 ◽  
Vol 5 (1) ◽  
pp. 50-63
Author(s):  
Heru Heryanto ◽  
Nur Laela ◽  
Riana R Dewi

This study aims to determine the significance of the influence of competence, independence, professionalism, auditor experience, accountability, and auditor's knowledge of audit quality. This study uses a questionnaire with a population and sample, namely all auditors who work at the Public Accounting Office (KAP) in the Special Region of Yogyakarta and Surakarta. Sampling techniques using Convenience Sampling with a sample of 61 respondents. The data used in this study is a questionnaire using a Likert scale 1 to 5. The data analysis technique used in this study is multiple linear regression using the SPSSprogram for Windows. The analysis tool in this study using validity and reliability, the classical assumption (normality test, multicollinearity, heteroscedasticity test and autocorrelation test) while the data were analyzed using multiple linear regression test, t test, F test and the coefficient of determination (R2).Based on the results of the t-test analysis performed, it shows that there is a positive influence of competence, independence, professionalism, auditor experience, accountability, and auditor's knowledge of audit quality and simultaneously competency, independence, professionalism, auditor experience, accountability, and auditor knowledge variables affect quality audit


2018 ◽  
Vol 1 (2) ◽  
pp. 71
Author(s):  
Aan Eko Khusni Ubaidillah

The problems we face today live in a time of moral degradation and destruction. People feel proud if they can imitate the trend carried by the West; both in thought and lifestyle. Ironically, not a few generations of Muslims who terpedaya with the trend. They make Western values ​​as their standard of behavior and morals. Meanwhile, Islamic morality is increasingly felt strange and difficult to practice in the midst of society facing such problems plural and complex. The purpose of this study are: 1) To describe the steps Implementation of values ​​of Ethics, Moral and Morals in learning behavior in STIT Raden Wijaya Mojokerto. 2) To describe the supporting and inhibiting factors Implementation of Ethics, Morals and Morals values ​​in the behavior of learning in STIT Raden Wijaya Mojokerto This research type is field research research using qualitative approach. Data collection techniques include observation, interview, and documentation. Data analysis technique uses descriptive explorative, that is by describing state and phenomenon status. Based on the exposure of the analysis of data sources can be concluded that: 1) Steps Implementation of values ​​of Ethics, Morals and Morals in the behavior of learning in STIT Raden Wijaya Mojokerto is the first institution to make a mature planning, then applied with the pattern pembiasaan. 2) To describe the supporting and inhibiting factors Implementation of Ethics, Morals and Morals values ​​in learning behavior in STIT Raden Wijaya Mojokerto consists of internal factors (consisting of heredity, gender, physical character, personality, intelligence and talent) and external ( consisting of education, religion, culture, environment and socio-economic)


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