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Tytuł:
Sound and vibration analysis for 70 m supply vessel in aspect of underwater noise reduction
Autorzy:
Weryk, M.
Kusmirek-Ochrymiuk, M.
Powiązania:
https://bibliotekanauki.pl/articles/331657.pdf
Data publikacji:
2008
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
underwater noise reduction
hydroacoustics
vessel
Opis:
The underwater noise and on-board noise measurement analysis, for 70 m supply ship, are presented in the paper, as well as the noise data for main machinery installed on-board. The results were completed by vibration measurements, then comparative analysis and identification of main sources of sound were executed. The main aim for this project was to analyse noise propagation and identify main noise excitation components resulting in underwater noise propagation. Some preliminary proposals of underwater noise reduction are put forward in the paper.
Źródło:
Hydroacoustics; 2008, 11; 431-440
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Model of Interactive System for Training in the Proper Use of Hearing Protection Devices
Autorzy:
Górski, P.
Powiązania:
https://bibliotekanauki.pl/articles/176568.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
active noise reduction
hearing protectors
Opis:
In 2011, over 520 thousand persons worked in hazardous conditions (according to the GUS). Among hazardous factors related to working environment noise was found to be the most common one, threatening 199,6 thousand people (52.9% threats-per-persons related to working environment). The prevalence of workplace noise and increasing awareness of effects of its impact on the human body causes increase of the demand for knowledge of the methods of noise reduction. Due to the lack of knowledge concerning the proper use of hearing protectors, effective noise exposure in the real world may be about a dozen dB higher than the declared assumed protection value. For this reason, in Central Institute for Labour Protection – NRI “The interactive system for learning the correct use of hearing protectors” has been developed. The system includes a multimedia guide on hearing protectors supplemented by video tutorials, training materials with training hearing protectors, and software for evaluation of the activities of the trainee.
Źródło:
Archives of Acoustics; 2014, 39, 1; 11-15
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Active Noise Reduction Algorithm Based on NOTCH Filter and Genetic Algorithm
Autorzy:
Górski, P.
Morzyński, L.
Powiązania:
https://bibliotekanauki.pl/articles/177549.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
active noise reduction
hearing protectors
Opis:
Application of active noise reduction (ANR) systems in hearing protectors requires the use of control algorithms to ensure stability of the ANR system and at the same time highly effective active noise reduction. A control algorithm based on NOTCH filters is an example of solutions that meet these criteria. Their disadvantage is operation over a narrow frequency band and a need for prior determination of frequencies to be reduced. This paper presents a solution of the ANR system for hearing protectors which is controlled with the use of modified NOTCH filters with parameters determined by a genetic algorithm. Application of a genetic algorithm allows to change the NOTCH filter reference signal frequency, and thus, adapt the filter to the reduced signal frequency.
Źródło:
Archives of Acoustics; 2013, 38, 2; 185-190
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A pulse noise detection algorithm using phase scattering
Autorzy:
Kardasz, P.
Powiązania:
https://bibliotekanauki.pl/articles/376739.pdf
Data publikacji:
2017
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
signal processing
audio reconstruction
noise reduction
Opis:
One of the most difficult problems that appears during the process of archival sound restoration is the detection and reduction of the pulse type noise. This kind of noise is the result of contamination or damage to the analog record material. Pulse interference detection algorithms are prone to false positive results. Therefore, to ensure high reliability of the pulse detection process, more than one algorithm should be used and then the results of these algorithms should be analyzed using advanced methods, including intelligent algorithms. The paper presents the pulse detection algorithm based on the phase scattering. Since the Dirac impulse and white noise have the same amplitude part of their spectra, the phase scattering transforms the pulse to the noise. Then a pulse can be detected by comparing the envelope of the original and processed signals. The proposed algorithm has been tested using synthetic test signals as well as a fragment of the archival recording on the damaged record. The directions of further research are outlined.
Źródło:
Poznan University of Technology Academic Journals. Electrical Engineering; 2017, 91; 165-173
1897-0737
Pojawia się w:
Poznan University of Technology Academic Journals. Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Use of Acoustic Camera for Noise Sources Localization and Noise Reduction in the Industrial Plant
Autorzy:
Fiebig, Wiesław
Dąbrowski, Damian
Powiązania:
https://bibliotekanauki.pl/articles/178071.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
noise source localization
noise reduction
industrial noise control
acoustic camera
Opis:
The paper presents results of the localization of main noise sources in the industrial plant. Identification of main noise sources was made with an acoustic camera using Beamforming Method. Parallel to the measurements by means of the acoustic camera, sound level measurements on the main noise sources have been performed. Based on the calculations, prediction regarding the noise emission at residential buildings located near to the plant has been determined. Acoustic noise maps have been performed with LEQ Professional software, which includes the 3D geometry of the buildings inside the plant. It has been established that, after introduction of noise reduction measures in the plant, the noise levels at the observation points in the residential area meets the limit values.
Źródło:
Archives of Acoustics; 2020, 45, 1; 111-117
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of the Inter Teeth Volumes on the Noise Generation in External Gear Pumps
Autorzy:
Fiebig, W.
Powiązania:
https://bibliotekanauki.pl/articles/177707.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
gear pumps
noise reduction
simulation
inter teeth volume
Opis:
The paper shows the new method for noise reduction in external gear pumps based on the analysis of the pressure in inter teeth volumes. The simulation model and measurement results of pressure changes in the inter teeth volume has been presented. Based on simulation results an additional volume has been obtained, which is connected to the inter teeth volume (decompression filter volume). Due this additional volume the build down processes in the pump are longer and the pressure overdue in the inter teeth volumes are smaller. This leads to the reduction of the dynamical excitation forces inside the pump and noise, especially in the higher frequency range I.
Źródło:
Archives of Acoustics; 2014, 39, 2; 261-266
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Noise Reduction of Spiral Ducts
Autorzy:
Łapka, W.
Cempel, C.
Powiązania:
https://bibliotekanauki.pl/articles/90374.pdf
Data publikacji:
2007
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
spiral duct
noise reduction
sound propagation
computational modeling
Opis:
The paper presents noise reduction (NR) of spiral ducts as a result of computational modeling of acoustic wave propagation. Three-dimensional models were created with the finite element method in COMSOL Multiphysics version 3.3. Nine models of spiral ducts with 1–9 spiral leads were considered. Time-harmonic analysis was used to predict NR, which was shown in spectral and interval frequency bands. Spiral duct performance can be seen as a comparison of NR before and after a change from a circular to a spiral duct.
Źródło:
International Journal of Occupational Safety and Ergonomics; 2007, 13, 4; 419-426
1080-3548
Pojawia się w:
International Journal of Occupational Safety and Ergonomics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Business plan concept for the production of rubber-based noise reduction walls in slovakia for the potential of worn tires material recovery
Autorzy:
Potkány, Marek
Krajčírová, Lucia
Osvaldová, Mária
Powiązania:
https://bibliotekanauki.pl/articles/2204122.pdf
Data publikacji:
2022
Wydawca:
STE GROUP
Tematy:
circular economy
noise reduction wall
recycling
rubber
tires
Opis:
The automotive industry is one of the fastest growing sectors and therefore places demand on many other sectors and increases the need for cooperation. With the development of the automotive industry, tires have become an integral part of society and the everyday life of the individual. As a result of the company's development as a connection of transport, the demand for tires is increasing and the production of waste tires is also related to this. The use of end-of-life tires is almost endless and that is why tires are good to use in the circular economy. The circular economy is an economic system that aims to keep products and materials in use for longer, thus increasing their productivity and reducing waste. The paper presents a methodical concept of the plan for the extension of production capacities of rubber-based pressed products with the intention to produce noise reduction panels. The investment consists of the acquisition of the pressing machine and respective mould in the amount of € 180,000. Based on the selected assessment methods it can be stated that the NPV reaches + 69,360 €, Profitability index is 1.38, Internal Rate of Return is 23.8% and the payback period is estimated for 4 years and 4 months, at the considered production capacity of 14,000 m2/year.
Źródło:
Management Systems in Production Engineering; 2022, 2 (30); 140--145
2299-0461
Pojawia się w:
Management Systems in Production Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Noise reduction at the shooting range by means of level-dependent hearing protectors
Autorzy:
Młyński, Rafał
Kozłowski, Emil
Powiązania:
https://bibliotekanauki.pl/articles/2162681.pdf
Data publikacji:
2019-06-14
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
impulse noise
earplugs
attenuation
earmuffs
noise reduction
level-dependent hearing protectors
Opis:
Background The aim of the tests was to establish the possibilities of reducing impulse noise by using level-dependent hearing protectors at a shooting range. The tests included 9 models of level-dependent earmuffs and 2 models of level-dependent earplugs. They were conducted in the presence of impulse noise generated by 7 types of firearms (pistols, a submachine gun, rifles, a shotgun). Material and Methods The tests were conducted at an outdoor shooting range, using an acoustic test fixture that meets the requirements of the ANSI/ASA S12.42-2010 standard. Noise parameters were established for the noise reaching the microphones installed in the ear simulators of the acoustic test fixture: uncovered and protected by the tested hearing protectors. Results All 11 tested level-dependent hearing protectors allow to satisfactorily (below the exposure limit values) reduce the C-weighted peak sound pressure level and A-weighted maximum sound pressure level parameters of noise produced during shots from the 7 types of firearms included in the study. Moreover, in the most unfavorable case, the permissible number of impulses due to the value of the A-weighted noise exposure level normalized to an 8-h working day parameter exceeds 5000 per day. Conclusions Level-dependent hearing protectors constitute the appropriate means to protect the hearing of people at a shooting range, while maintaining the functionality of these protection devices to transmit speech signals. Med Pr. 2019;70(3):265–73
Źródło:
Medycyna Pracy; 2019, 70, 3; 265-273
0465-5893
2353-1339
Pojawia się w:
Medycyna Pracy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Selected aspects of modeling mufflers for exhaust systems of vehicles
Autorzy:
Gągorowski, A.
Melon, A.
Powiązania:
https://bibliotekanauki.pl/articles/245148.pdf
Data publikacji:
2013
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
vehicles
noise reduction
exhaust system
mufflers
efficiency of attenuation
Opis:
The world used several solutions exhaust systems of motor vehicles. Today, in addition to the core function of which is to discharge exhaust gases from a combustion engine and noise reduction, these systems must comply with the functions associated with aftertreatment and impact on the characteristics of the engine. Requirements increase for noise suppression, at the tendency to increase engine efficiency and reduce fuel consumption. On the other hand, it seeks to reduce production costs. All this forces the search for new solutions and improve existing ones. In the process of the combustion gases discharge it is also important to eliminate frequency bands especially harmful to people and the environment (including other living organisms). Our goal is to develop a new design muffler of exhaust system that will meet these expectations of producers and users of vehicles. For this purpose, mathematical analysis of a classical systems with circular holes in the perforated pipes and proposed by the authors of the longitudinal gaps systems was performed. The paper presents some aspects of mufflers modeling for reducing acoustic noise emitted from the vehicle. Basic criterion for assessing was therefore the damping effect. Built theoretical models have allowed a rough estimate of acoustic performance at specific frequency bands by determining the transfer impedances. Because the noise reduction in automobiles is a complex, for the construction of such systems one of the important elements is to eliminate these frequency bands of acoustic waves in the process of the exhaust gases discharge which are the most dangerous to humans. The comparative analysis of these systems has allowed to determine the direction of further structural changes.
Źródło:
Journal of KONES; 2013, 20, 2; 97-103
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Variable Sound Insulation Structure with MFC Elements
Autorzy:
Górski, P.
Kozupa, M.
Powiązania:
https://bibliotekanauki.pl/articles/177289.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sound insulation
active noise reduction
macro fiber composite (MFC)
Opis:
Additional sound sources are used as actuators in the vast majority of active noise reduction systems. One of the possible opportunities to extend the field of applications of active noise reduction systems is using active structures of variable sound insulation. The paper presents an analysis of ways of reducing noise with a structure of variable sound insulation consisting of a metal plate, active elements (Macro Fiber Composite), and a control system. The paper presents results of acoustic radiation simulations and measurements of sound intensity generated by the structure under the influence of stimulation by an acoustic wave. Simulations of mechanical vibrations and acoustic radiation for the plate were performed with the finite element method and ANSYS software. Simulation results made it possible to select locations for gluing the active elements and sensors. Analyses of the sound pressure level in the space to which the plate is radiating made it possible to determine dominant frequencies in the characteristics and, as a result, indicate vibration modes that can be reduced. Sound intensity measurements were performed with a three-way probe of USP mini Microflown. Results of simulations and measurements show that it is possible to achieve an improvement of the insulating power of a metal plate by approx. 10 dB.
Źródło:
Archives of Acoustics; 2012, 37, 1; 115-120
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
HEVC Encoding Assisted with Noise Reduction
Autorzy:
Stankiewicz, O.
Wegner, K.
Karwowski, D.
Stankowski, J.
Klimaszewski, K.
Grajek, T.
Powiązania:
https://bibliotekanauki.pl/articles/226110.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
HEVC encoding
encoder control
model selection optimization
noise reduction
Opis:
Optimization of encoding process in video compression is an important research problem, especially in the case of modern, sophisticated compression technologies. In this paper, we consider HEVC, for which a novel method for selection of the encoding modes is proposed. By the encoding modes we mean e.g. coding block structure, prediction types and motion vectors. The proposed selection is done basing on noise-reduced version of the input sequence, while the information about the video itself, e.g. transform coefficients, is coded basing on the unaltered input. The proposed method involves encoding of two versions of the input sequence. Further, we show realization proving that the complexity is only negligibly higher than complexity of a single encoding. The proposal has been implemented in HEVC reference software from MPEG and tested experimentally. The results show that the proposal provides up to 1.5% bitrate reduction while preserving the same quality of a decoded video.
Źródło:
International Journal of Electronics and Telecommunications; 2018, 64, 3; 285-292
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Time series denoising with wavelet transform
Autorzy:
Kozłowski, B.
Powiązania:
https://bibliotekanauki.pl/articles/309048.pdf
Data publikacji:
2005
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
wavelet transform
WaveShrink
filtration
noise reduction
Haar basic wavelet function
Opis:
This paper concerns the possibilities of applying wavelet analysis to discovering and reducing distortions occurring in time series. Wavelet analysis basics are briefly reviewed. WaveShrink method including three most common shrinking variants (hard, soft, and non-negative garrote shrinkage functions) is described. Another wavelet-based filtering method, with parameters depending on the length of wavelets, is introduced. Sample results of filtering follow the descriptions of both methods. Additionally the results of the use of both filtering methods are compared. Examples in this paper deal only with the simplest "mother" wavelet function - Haar basic wavelet function.
Źródło:
Journal of Telecommunications and Information Technology; 2005, 3; 91-95
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Methods for quality improvement of multibeam and LiDAR point cloud data in the context of 3D surface reconstruction
Autorzy:
Kulawiak, M.
Łubniewski, Z.
Powiązania:
https://bibliotekanauki.pl/articles/332451.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
multibeam sonar
LiDAR
3D
point cloud
shape reconstruction
noise reduction
Opis:
Point cloud dataset is the transitional data model used in several marine and land remote-sensing applications. During further steps of processing, the transformation of point cloud spatial data to more complex models containing higher order geometric structures like edges and facets may be possible, if an appropriate quality level of input data is provided. Point cloud datasets usually contain a considerable amount of undesirable irregularities, such as strong variability of local point density, missing data, overlapping points and noise caused by scattering characteristics of the environment. For these reasons, processing such data can be quite problematic, especially in the field of object detection and threedimensional surface reconstruction. This paper is focused on applying the proposed methods for reducing the mentioned irregularities from several datasets containing 3D point clouds acquired by multibeam sonars and LiDAR scanners. The article also presents the results obtained by each method, and discusses their advantages.
Źródło:
Hydroacoustics; 2016, 19; 251-258
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Non-local Mean-Shift filter for the reduction of multiplicative noise in digital images
Autorzy:
Kusnik, D.
Smołka, B.
Powiązania:
https://bibliotekanauki.pl/articles/334035.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Śląski. Wydział Informatyki i Nauki o Materiałach. Instytut Informatyki. Zakład Systemów Komputerowych
Tematy:
image enhancement
multiplicative noise reduction
poprawa jakości obrazu
multiplikatywna redukcja szumów
Opis:
In this paper a new method for the reduction of multiplicative noise in digital images is described. The proposed algorithm is a modification of the Mean-Shift (MS) filter which is based on the concept of the Non-Local Means (NLM) denoising. The proposed algorithm does not focus on single pixels only, as in the case of the mean-shift technique, but also on their neighborhoods. The performance of the novel approach is experimentally verified and the obtained results prove that the new design is superior both to the MS and NLM techniques.
Źródło:
Journal of Medical Informatics & Technologies; 2014, 23; 103-110
1642-6037
Pojawia się w:
Journal of Medical Informatics & Technologies
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 40

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