Search Results

You are looking at 1 - 8 of 8 items for

  • Author: Maciej Szczodrak x
Clear All Modify Search
Open access

Andrzej Czyżewski, Józef Kotus and Maciej Szczodrak

Abstract

The implemented online urban noise pollution monitoring system is presented with regard to its conceptual assumptions and technical realization. A concept of the noise source parameters dynamic assessment is introduced. The idea of noise modeling, based on noise emission characteristics and emission simulations, was developed and practically utilized in the system. Furthermore, the working system architecture and the data acquisition scheme are described. The method for increasing the speed of noise map calculation employing a supercomputer is explained. The practical implementation of noise maps generation and visualization system is presented, together with introduced improvements in the domain of continuous noise monitoring and acoustic maps creation. Some results of tests performed using the system prototype are shown. The main focus is put on assessing the efficiency of the acoustic maps created with the discussed system, in comparison to results obtained with traditional methods.

Open access

Józef Kotus, Maciej Szczodrak, Andrzej Czyżewski and Bożena Kostek

Abstract

The results of long-term continuous noise measurements in two selected schools are presented in the paper. Noise characteristics were measured continuously there for approximately 16 months. Measurements started eight months prior to the acoustic treatment of the school corridors of both schools. An evaluation of the acoustic climates in both schools, before and after the acoustic treatment, was performed based on comparison of these two periods of continuous measurements. The autonomous noise monitoring stations, engineered at the Multimedia Systems Department of the Gdańsk University of Technology were used for this purpose. Investigations of measured noise, especially its influence on hearing sense, assessed on ground of spectral analyses in critical bands, is discussed. Effects of occupational noise exposure, including the Temporary Threshold Shift simulation, are determined. The correlation of the above said measurement results with respective instantaneous noise levels is discussed, and concluding remarks are presented. Some additional indicators such as air pollution or video analysis aiming at the analysis of corridor occupancy are also measured. It should be remembered that excessive noise, or air pollution may be evidence of a dangerous event and may pose health risks.

Open access

Józef Kotus, Maciej Szczodrak, Andrzej Czyżewski and Bożena Kostek

Distributed System for Noise Threat Evaluation Based on Psychoacoustic Measurements

An innovative system designed for the continuous monitoring of acoustic climate of urban areas was presented in the paper. The assessment of environmental threats is performed using online data, acquired through a grid of engineered monitoring stations collecting comprehensive information about the acoustic climate of urban areas. The grid of proposed devices provides valuable data for the purpose of long and short time acoustic climate analysis. Dynamic estimation of noise source parameters and real measurement results of emission data are utilized to create dynamic noise maps accessible to the general public. This operation is performed through the noise source prediction employing a propagation model being optimized for computer cluster implementation requirements. It enables the system to generate noise maps in a reasonable time and to publish regularly map updates in the Internet. Moreover, the functionality of the system was extended with new techniques for assessing noise-induced harmful effects on the human hearing system. The principle of operation of the dosimeter is based on a modified psychoacoustic model of hearing and on the results of research performed with participation of volunteers concerning the impact of noise on hearing. The primary function of the dosimeter is to estimate, in real time, auditory effects which are caused by exposure to noise. The results of measurements and simulations performed by the system prototype are depicted and analyzed. Several cases of long-term and short-term measurements of noise originating from various sources were considered in detail. The presented outcomes of predicted degree of the hearing threshold shift induced during the noise exposure can increase the awareness of harmfulness of excessive sound levels.

Open access

Karolina Marciniuk, Maciej Szczodrak and Bożena Kostek

Abstract

In the paper, a noise map service designated for the user interested in environmental noise is presented. Noise prediction algorithm and source model, developed for creating acoustic maps, are working in the cloud computing environment. In the study, issues related to the noise modelling of sound propagation in urban spaces are discussed with a particular focus on traffic noise. Examples of results obtained through a web application created for that purpose are shown. In addition, these are compared to results obtained from the commercial software simulations based on two road noise prediction models. Moreover, the computing performance of the developed application is investigated and analyzed. In the paper, a flowchart simulating the operation of the noise web-based service is presented showing that the created application is easy to use even for people with little experience in computer technology.

Open access

Maciej Szczodrak and Andrzej Czyżewski

Abstract

Results of investigation of face detection algorithms efficiency in the banking client visual verification system are presented. The video recordings were made in real conditions met in three bank operating outlets employing a miniature industrial USB camera. The aim of the experiments was to check the practical usability of the face detection method in the biometric bank client verification system. The main assumption was to provide a simplified as much as possible user interaction with the application. Applied algorithms for face detection are described and achieved results of face detection in the real bank environment conditions are presented. Practical limitations of the application based on encountered problems are discussed.

Open access

Maciej Szczodrak, Józef Kotus, Bożena Kostek and Andrzej Czyżewski

Abstract

The paper presents functionality and operation results of a system for creating dynamic maps of acoustic noise employing the PL-Grid infrastructure extended with a distributed sensor network. The work presented provides a demonstration of the services being prepared within the PLGrid Plus project for measuring, modeling and rendering data related to noise level distribution in city agglomerations. Specific computational environments, the so-called domain grids, are developed in the mentioned project. For particular domain grids, specialized IT solutions are prepared, i.e. software implementation and hardware (infrastructure adaptation), dedicated for particular researcher groups demands, including acoustics (the domain grid “Acoustics”). The infrastructure and the software developed can be utilized mainly for research and education purposes, however it can also help in urban planning. The engineered software is intended for creating maps of noise threat for road, railways and industrial sources. Integration of the software services with the distributed sensor network enables automatic updating noise maps for a specific time period. The unique feature of the developed software is a possibility of evaluating auditory effects which are caused by the exposure to excessive noise. The estimation of auditory effects is based on calculated noise levels in a given exposure period. The outcomes of this research study are presented in a form of the cumulative noise dose and the characteristics of the temporary threshold shift.

Open access

Piotr Odya, Józef Kotus, Maciej Szczodrak and Bożena Kostek

Abstract

The aim of the paper was to compare acoustic field around the open and stopped organ pipes. The wooden organ pipe was located in the anechoic chamber and activated with a constant air flow, produced by an external air-compressor. Thus, a long-term steady state response was possible to obtain. Multi-channel acoustic vector sensor was used to measure the sound intensity distribution of radiated acoustic energy. Measurements have been carried out on a defined fixed grid of points. A specialized Cartesian robot allowed for a precise positioning of the acoustic probe. The resulted data were processed in order to obtain and visualize the sound intensity distribution around the pipe, taking into account the type of the organ pipe, frequency of the generated sound, the sound pressure level and the direction of acoustic energy propagation. For the open pipe, an additional sound source was identified at the top of the pipe. In this case, the streamlines in front of the pipe are propagated horizontally and in a greater distance than in a case of the stopped pipe, moreover they are directed downwards. For the stopped pipe, the streamlines of the acoustic flow were directed upwards. The results for both pipe types were compared and discussed in the paper.

Open access

Maciej Szczodrak, Adam Kurowski, Józef Kotus, Andrzej Czyżewski and Bożena Kostek

Abstract

A system setup for measurements of acoustic field, together with the results of 3D visualisations of acoustic energy flow are presented in the paper. Spatial sampling of the field is performed by a Cartesian robot. Automatization of the measurement process is achieved with the use of a specialized control system. The method is based on measuring the sound pressure (scalar) and particle velocity(vector) quantities. The aim of the system is to collect data with a high precision and repeatability. The system is employed for measurements of acoustic energy flow in the proximity of an artificial head in an anechoic chamber. In the measurement setup an algorithm for generation of the probe movement path is included. The algorithm finds the optimum path of the robot movement, taking into account a given 3D object shape present in the measurement space. The results are presented for two cases, first without any obstacle and the other - with an artificial head in the sound field.