2 edition of Variability of ship noise measurements found in the catalog.
Variability of ship noise measurements
Canada. Defence Research Establishment Atlantic.
|Series||Canada. Defence Research Establishment Atlantic. Research and Development Branch. Technical memorandum -- 88/210|
|The Physical Object|
|Pagination||v, 34 p.|
|Number of Pages||34|
out being reliable. The book, Standards for Educational and Psychological Testing (), provides guidance for all phases of test development. 2. The Four Types of Reliability a. Test-Retest reliability (also called Stability) answers the question, “Will the scores be stable over time.” A test or measure is administered. SomeFile Size: KB. Furthermore, ship noise was observed to radiate asymmetrically. Stern aspect noise levels are 5 to 10 dB higher than bow aspect noise levels. Collectively, these results emphasize the importance of including modern ship-types in quantifying shipping noise for predictive models of global, regional, and local marine environ-ments.
Example problems are used throughout to relate the basic laws of acoustics to practical applications. The book illustrates the uses of personal computers to evaluate noise problems and noise control techniques. Interpretation of data from measurements and theoretical predictions are emphasized, and alternative noise control techniques are by: noise sources. Ship propulsion, machinery in ships and off-shore installations, off-shore construction activities all produce unnecessary sound as an incidental by-product. The noise levels generated in air and underwater may be excessive in terms of crew and passenger safety or comfort. The noise may injure or disturb marine life in the.
Controlling noise is therefore a defense measure, most acutely for submarines. Prevention. At the design table, the naval architect makes the necessary choices concerning the ship's structure to achieve an optimized design towards noise and vibration control. Decisions are made about the engine and shaft, what kind of instruments and material. 1. Measures of Variability MARY KRYSTLE DAWN D. SULLEZA Reporter CHAPTER FOUR: 2. VARIABILITY: the “spread” in a set of measurement. -it refers to how spread out a group of data is. In other words, variability measures how much your scores differ from each other. Variability is also referred to as dispersion or g: ship noise.
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Variability of underwater radiated ship noise measured using two hydrophone arrays Abstract: The impacts of man-made underwater noise on the marine environment have received increased attention over recent years, primarily resulting from recognition of the increased pressures placed on the oceans by human by: 2.
evidence provides important findings. Critically, very significant variability exists in real underwater noise performance and the related vibrations when compared to median measurements and fixed targets. Technical and cost implications of this observation should be considered by initial ship designs or update programmes.
Part of the Astrophysics and Space Science Library book series (ASSL, volume ) Abstract Quantitative measurements of a variable signal in the presence of noise requires careful attention to subtle affects which can easily bias the by: 1.
Final Report: Measuring Ship Noise. Page 9. Background noise Before and after recording a target ship, background noise was measured for at least s by the same hydrophone and data acquisition system, when the target ship was more than km (5 nautical miles) away from Song of the Size: KB.
Measurement of radiated ship noise. A methodology is presented for measuring the radiated noise from a ship in shallow water, and deriving the source level spectrum. The method is applied to the measurement of dredgers in UK waters, vessels which are restricted to shallow water during aggregate extraction.
ship noise measurements have been addressed and limits to the radiated noise have been de- veloped in order to reduce the shipping impact on the marine fauna. In view of the e- enforc. frequency variation with time. Key-Words: underwater noise of ship, spectrogram Short Time Fourier Transform, Fast Fourier Transform analysis.
1 Introduction Human activity in the marine environment is an important component of the total sea acoustic background.
Sound is used both as a tool for probing theFile Size: KB. STATISTICAL ANALYSIS OF A NOISE MEASUREMENTS FOR THE SERIES OF RORO SHIPS Mateusz WERYK Ship Design and Research Centre Ship Structure Division Al.
Rzeczypospolitej 8, Gdansk, Poland´ e-mail: @ (received J ; accepted Novem ). underwater radiated noise sources, spectrum of ship radiated noise and model of ship radiated noise. ater Radiated Noise Ship, submarines and torpedoes are significant sources of underwater sound.
Radiated noise is of particular importance for passive sonar, which is designed to exploit the peculiarities of thisFile Size: KB. The most common measurement in environmental noise is the dB(A) level. It can be measured with a simple Sound Level Meter having an A-weighting filter to simulate the subjective response of the human ear.
The dB(A) level is used to report ambient noise and noise intrusions Missing: ship noise. frequency. The measurements were made in a water tank of dimensions x x m.
The schematic drawing of the measurement system was shown in the earlier paper “Tracking the Underwater Noise Source Using a Vector Sound-Intensity Probe” .
The noise radiated by ship is always measured by running this ship past a stationary. World War II studies of ship noise, particularly measurements of thousands of transits of hundreds of ships of all types, identified propeller cavitation as the dominant source of noise radiated by ships, including at high frequencies (Dow, Emling & Knudsen, ).
Chapter 5, Page 7 noise source to where the SPL falls to dBA should also be measured in addition to the hazard radius to 85 dBA. If applicable, this can also be performed for impulse or impact noise sources - for the distance from the noise source where the SPL falls to Size: KB.
Noise was monitored on a duty cycle of 1 min every 10 min at a sampling rate of kHz and 16 bits. This regime allowed for detection of ship passages with a similar time resolution to the AIS data (∼10 min; see below) while also providing recordings of marine mammal sounds up to Cited by: The standard also covers the manoeuvring of the vessel during the measurements.
The recommended test sequence is shown in Fig. 2 for the measurement of radiated noise from the starboard side of the vessel. The procedure requires the vessel to transit along a pre-determined path such that it passes the hydrophone array at the CPA point, perform a Williamson turn and Cited by: VARIABILITY IN AIRPLANE NOISE MEASUREMENTS By David A.
Hilton and Herbert R. Henderson NASA Langley Research Center SUMMARY This paper presents some of the acoustic data obtained during two measurement projects involving a turbofan airplane and an turbojet airplane along with infor.
Detection, classification, and tracking of small vessels are important tasks for improving port security and the security of coastal and offshore operations. Hydroacoustic sensors can be applied for the detection of noise generated by vessels, and this noise can be used for vessel detection, classification, and tracking.
This paper presents recent improvements aimed at the measurement Cited by: Annex 2c Determination of Noise Exposure (simplified procedure based on ISO ) Annex 2d Guidance on the Inclusion of Noise Issues in Safety or Occupational Health and Risk Management Systems Annex 2e Noise Measurement Report Annex 3 Vibration Measurement Report Annex 4 Application Form for Approval Rules I Ship TechnologyFile Size: KB.
Maritime shipping constitutes a major source of low-frequency noise in the ocean 1,2,3, particularly in the Northern Hemisphere where the majority of ship traffic frequencies below Cited by: with little variability around the target or nominal dimensions of the product’s quality char-acteristics.
Statistical process control (SPC)is a powerful collection of problem-solving tools useful in achieving process stability and improving capability through the reduction of Size: KB. Ship Structure Committee (Spence ). Note that this study focuses on excitations from machinery sources; all measurements were performed dockside.
Propulsion related excitations, (propeller, shaft, etc.) can also be a significant source of vibration on many vessels. PropellerFile Size: 2MB.Noise and Vibration Analysis is a complete and practical guide that combines both signal processing and modal analysis theory with their practical application in noise and vibration analysis.
It provides an invaluable, integrated guide for practicing engineers as well as a suitable introduction for students new to the topic of noise and by: the frequency (f), which is the number of pressure variation cycles in the medium per unit time, or simply, the number of cycles per second, and is expressed in Hertz (Hz).
Pink random noise contains equal energy per measurement band and thus 28 Fundamentals of .