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Wyświetlanie 1-15 z 32
Tytuł:
Communication Platform for Evaluation of Transmitted Speech Quality
Autorzy:
Ciarkowski, A.
Czyżewski, A.
Powiązania:
https://bibliotekanauki.pl/articles/307893.pdf
Data publikacji:
2011
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
acoustic echo cancelation
doubletalk detection
echo hiding
Opis:
A voice communication system designed and implemented is described. The purpose of the presented platform was to enable a series of experiments related to the quality assessment of algorithms used in the coding and transmitting of speech. The system is equipped with tools for recording signals at each stage of processing, making it possible to subject them to subjective assessments by listening tests or, ob- jective evaluation employing PESQ or PSQM algorithms. The functionality for the simulation of distortions typical for voice communication over the Internet was implemented, making it possible to obtain reproducible, quantifiable results. An application of the presented platform for evaluation of acoustic echo canceler algorithm based on watermarking techniques, which was developed earlier is presented as an example of an effective deployment of the described technology.
Źródło:
Journal of Telecommunications and Information Technology; 2011, 3; 95-101
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Galatians 6:17 and its Reception History: Assessing the Echoes
Autorzy:
Muir, Steven
Powiązania:
https://bibliotekanauki.pl/articles/43576582.pdf
Data publikacji:
2024
Wydawca:
Katolicki Uniwersytet Lubelski Jana Pawła II
Tematy:
Echo
Commentary
Scripture
Reception History
Opis:
This preface engages with the concept of echo as a creative way of generating ideas on how to assess issues in the reception history of a scripture text - here, Galatians 6:17.
Źródło:
Vox Patrum; 2024, 90; 29-34
0860-9411
2719-3586
Pojawia się w:
Vox Patrum
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Non-destructive diagnostics of concrete cantilever beam and slab by impact echo method
Nieniszcząca diagnostyka konstrukcji betonowych belek wspornikowych i płyty stropowej za pomocą metody impact echo
Autorzy:
Rucka, M.
Wilde, K.
Powiązania:
https://bibliotekanauki.pl/articles/327542.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
diagnostyka ultradźwiękowa
metoda impact-echo
konstrukcja betonowa
ultrasonic testing
impact echo
concrete structures
Opis:
This paper focuses on the application of the impact-echo method for the full scale tests conducted on concrete bridge cantilever beams and a floor slab. The method uses the phenomenon of propagating waves induced by an impact and registered by one or two accelerometers. Experimental studies proved the applicability of the impact-echo method for damage detection in the considered concrete structural elements.
Praca poświęcona jest zastosowaniu fal sprężystych na przykładzie w metody impact-echo. Metoda ta wykorzystuje zjawisko propagacji fal wzbudzanych przez mechaniczne uderzenie i ich pomiar za pomocą jednego lub dwóch akcelerometrów. Przeprowadzone testy eksperymentalne dla betonowych wsporników oraz stropu potwierdziły skuteczność metody w wykrywaniu uszkodzeń.
Źródło:
Diagnostyka; 2010, 3(55); 63-68
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Acoustic experiment on diel fish behaviour cycle performed in the Gotland Deep
Autorzy:
Orlowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/332560.pdf
Data publikacji:
2003
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
acoustic experiment
Gotland Deep
echo sounder
Opis:
This paper describes the results of 24 h acoustic experiment based on three-dimensional measurements of the S; distribution of herring and sprat in the southern Baltic in October 2001. The experiment was based on a continuous (24h day) integration offish echoes using an EY500 echo sounder from a vessel with a constant speed of 8 knots, moving along the sides of a square equal to 4 n.mi., localized inside the specified area. Duration of the experiment was limited by deterioration of the weather conditions but nearly 300 ESDU samples were collected. These are correlated with values of coincident environmental factors: time, depth, water temperature, salinity and oxygen levels; estimated on the basis of survey data. Fish behaviour vs environmental factors is described by different macrosounding visualizations, statistical, and mathematical models. The purpose of the paper is to compare results of the experiment to the average characteristics of fish behaviour in the same basin, based on autumn studies over the period 1995-2001. General analysis was provided for the selected area of the Polish EEZ (south Gotland Deep), characterized by the greatest depth movements of fish diel migration. The most significant differences were found between fish migration pattern and diel stability of the acoustic response between these situations, specially during the sunset period.
Źródło:
Hydroacoustics; 2003, 6; 19-30
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of in situ radiated noise of the platform used on shallow water area on echo sounder data in fisheries-acoustics
Autorzy:
Brehmer, P.
Guennegan, Y.
Arzelies, P.
Guillard, J.
Cheret, Y.
Duformentelle, P.
Colon, M.
Powiązania:
https://bibliotekanauki.pl/articles/332717.pdf
Data publikacji:
2003
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
in situ
echo sounder
fisheries
acoustics
Opis:
The shallow water area of the coastal fringes is important to take into consideration in fish stock assessment because a great part of the stock, especially for the small pelagic fish is distributed in this area (20). In shallow water research vessels are prohibited to navigation (usually <20m) and usually only small boats can be used. One of the main source error in acoustics fish sampling is due to the avoidance reaction generated by the three dimensional noise diagram emitted by the boat. In this paper we highlighted the importance of wind direction and strength in the noise diagram emitted by the boat under in situ condition. A comparison of the noise level of two boats (a Research Vessel and a Speedboat equipped of similar echo sounder) has been made before simultaneous records of echo sounder data: the speedboat is more silent as revealed by in situ hydrophone measurement and near the ICES recommendations. The observation of shoal echo sounder descriptors shows an avoidance reaction as expected more important for the noisier boat: there the schools avoid more the research vessel. The avoidance reaction is characterised by a deeper position of the fish school barycentre, in the water column, detected by the research vessel and a shoal minimum depth higher than for the speedboat. The effect of noise diagram difference is clear on the same shoal descriptors, the difference appears for the vertical position of the barycentre and minimum altitude.
Źródło:
Hydroacoustics; 2003, 6; 31-40
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Statistical properties of pulse-echo signal backscattered in trabecular bone
Autorzy:
Litniewski, J.
Powiązania:
https://bibliotekanauki.pl/articles/331602.pdf
Data publikacji:
2008
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
trabecular bone
pulse-echo signal
ultrasonic signal
Opis:
The paper considers the application of statistical properties of backscattered ultrasonic signal for assessment of the trabecular bone status. Computer simulations were conducted to investigate the properties of the ultrasound pulse-echo signal, as it is received on the transducer surface after scattering in trabecular bone. Results indicated that while for the well-defined trabeculae properties within the simulated bone structure the signal envelope values are Rayleigh distributed the significant departures from Rayleigh statistics may be expected as the thickness of trabeculae become random. The influence of the altering of mechanical properties of the bone tissue building the trabeculae on the signal statistical parameters was unnoticeable. The initial experiments confirming some cases of departure from Rayleigh statistics for envelopes of backscattered signals are also discussed.
Źródło:
Hydroacoustics; 2008, 11; 253-264
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Detection of Small Bottom Objects from Multibeam Echosounder Data
Autorzy:
Iwen, D.
Wąż, M.
Powiązania:
https://bibliotekanauki.pl/articles/320733.pdf
Data publikacji:
2018
Wydawca:
Polskie Forum Nawigacyjne
Tematy:
Multibeam Echo sounder
bathymetric survey
bottom object
detection
Opis:
Multibeam Echo Sounder Systems (MBES) shallow water surveys provide capability not only acquiring bathymetric data useful for determining isobaths and mapping features on the seafloor which may be a hazard to navigation. They also allow detection of objects smaller or deeper than those required for the safety of seafaring and International Hydrography Organization (IHO) standards. In this article some of issues related to of efficient MBES shallow water surveys are stressed. Additionally a draft of post-processing techniques and result data format together with tools allowing extraction of bottom object from bathymetric data are presented.
Pomiary na płytkich wodach z użyciem systemu echosondy wielowiązkowej dają możliwości pozyskiwania danych batymetrycznych przydatnych do aproksymacji izobat, ale również mapowania cech dna morskiego mogących stanowić niebezpieczeństwo dla nawigacji. Ponadto pozwalają wykryć obiekty mniejsze lub położone głębiej niż wymaga tego standard Międzynarodowej Organizacji Hydrograficznej dla zapewnienia bezpiecznej żeglugi. W tym artykule zwrócono uwagę na pewne zagadnienia odnoszące się do wydajności pomiarów z użyciem echosondy wielowiązkowej na płytkich wodach. Ponadto przedstawiono sugestie odnośnie technik opracowania danych w trybie post-processingu wraz z dyskusją przydatności konkretnych formatów danych w przypadku posługiwania się wybranymi narzędziami dla wydzielenia obiektów dennych spośród danych batymetrycznych.
Źródło:
Annual of Navigation; 2018, 25; 219-232
1640-8632
Pojawia się w:
Annual of Navigation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Derecho radar analysis of August 11, 2017
Autorzy:
Łuszczewski, Hubert
Tuszyńska, Irena
Powiązania:
https://bibliotekanauki.pl/articles/2142339.pdf
Data publikacji:
2022
Wydawca:
Instytut Meteorologii i Gospodarki Wodnej - Państwowy Instytut Badawczy
Tematy:
meteorology
derecho
bow echo
mesocyclone
analysis
radar
Doppler
Opis:
This paper presents an analysis of the derecho phenomenon that occurred over Poland on August 11, 2017. The storm caused 6 fatalities, 39 injuries (Mańczak et al. 2022), and some of the greatest damage in the history of Polish forestry. Our study is based on radar meteorology and measurements from the Polish POLRAD radar network, and intended for advanced meteorologists with good knowledge of radar measurements. The research used both standard and specialized radar products as well as classic and Doppler scan data. The Doppler velocity products were especially useful for showing the characteristics of the storm. The analysis was mainly based on data from two radars: Poznań and Gdańsk, but the composite maps, consisting of data from more than one radar, were also analyzed. The derecho complex developed from unorganized thunderstorm cells over SW Poland and moved toward the NE. The various stages of the evolution of the system are presented and analyzed, accounting for the formation of a SC, the development of a rear inflow jet (RIJ), the split of the entire system, and the appearance of the bow echo signature. Significant factors affecting the scale of the wind damage were: (1) the extensive mesocyclone which evolved to the mesoscale convective vortex (MCV), and (2) a strong rear flank downdraft interacting with the rear inflow jet (RIJ).
Źródło:
Meteorology Hydrology and Water Management. Research and Operational Applications; 2022, 10, 2; 1--25
2299-3835
2353-5652
Pojawia się w:
Meteorology Hydrology and Water Management. Research and Operational Applications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Metanalysis and phonaesthesia as sources of secondary initials in Irish
Metanaliza i fonestezja jako źródła spółgłosek inicjalnych w irlandzkim
Autorzy:
Chudak, Magdalena
Powiązania:
https://bibliotekanauki.pl/articles/1886407.pdf
Data publikacji:
2015
Wydawca:
Katolicki Uniwersytet Lubelski Jana Pawła II. Towarzystwo Naukowe KUL
Tematy:
język irlandzki
metanaliza
echo-frazy
reduplikacja
reduplikacja rymująca
fonestezja
symbolika dźwiękowa
Irish dialect
metanalysis
echo-phrases
reduplication
phonaesthetics sound symbolism
Opis:
Celem artykułu jest wskazanie źródeł powstania trzech irlandzkich spółgłosek inicjalnych, których obecność na początku danych wyrazów nie może być uzasadniona etymologicznie. Dyskusja dotyczy segmentów n-, t- i s-. Dowiedziono, że dwie pierwsze samogłoski, poprzez proces metanalizy (Jespersen 1914), zostały błędnie „przeniesione” z końcówki przedimka określającego an, an t- do inicjalnej pozycji następującego po nim słowa. Z kolei spólgłoska s- pełni funkcję fonestemu (Bloomfield 1933), a zatem segmentu wspólnego dla pewnej semantycznie zdefiniowanej grupy wyrazów. Na podstawie przykładów z różnych języków indoeuropejskich wykazano, że spółgłoska s- nadaje wyrazom zwykle koloryt pejoratywny.
The contention of the article is to account for the sources of three non-etymological initial consonants in Irish, i.e. n-, t-, and s-. It is shown that the initial n- and t-, originally belonging to the definite article, attach to vowel-initial words through the process of metanalysis. Non-historical s-, in turn, operates as a phonaestheme, a segment serving an expressive function, identified universally in Indo-European languages as pejorative.
Źródło:
Roczniki Humanistyczne; 2015, 63, 11; 53-65
0035-7707
Pojawia się w:
Roczniki Humanistyczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Conditions for multiple acquisition of echoes from stationary targets in successive transmissions of active sonars
Autorzy:
Kilian, Lech
Schmidt, Aleksander
Rudnicki, Mariusz
Powiązania:
https://bibliotekanauki.pl/articles/24201958.pdf
Data publikacji:
2022
Wydawca:
Politechnika Poznańska. Instytut Mechaniki Stosowanej
Tematy:
echosounder
sonar
side scan sonar
multiple echo
beam geometry
scanning speed
echosonda
sonar boczny
echo wielokrotne
geometria belki
prędkość skanowania
Opis:
In echolocation, the highest possible number of contacts with a detected target is clearly decisive on the possibilities of echo processing to optimise the estimation of distinctive characteristics of the observed target. In hydrolocation, the slow propagation of acoustic waves in water reduces the number of contacts of echosounders and sonars with detected targets. The article considers model conditions for acquiring multiple contacts with stationary targets detected by various sounding methods - with echosounders, classic active sonars and side looking sonars. Appropriate formulas explicitly linking the possible number of echo signals from the target in a specific geometry of the survey performed at the assumed speed are presented. These formulas are intuitively clear and not very complicated, but their value lies in the ability to instantly combine the vessel speed with the sounding effects, and may be a clear argument for imposing a low sounding speed, which make it difficult to steer the vessel.
Źródło:
Vibrations in Physical Systems; 2022, 33, 3; art. no. 2022308
0860-6897
Pojawia się w:
Vibrations in Physical Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Selective Exposure on Polish Political and News Media Facebook Pages
Autorzy:
Matuszewski, Paweł
Powiązania:
https://bibliotekanauki.pl/articles/1790671.pdf
Data publikacji:
2019-06-19
Wydawca:
Polskie Towarzystwo Socjologiczne
Tematy:
selective exposure
social media
echo chamber
beliefs
news media
Opis:
Increasing numbers of citizens rely on social media to gather both political and non-political information. This fact raises questions about belief formation and belief updating in the social media setting. Using Facebook data on users’ behaviour in Poland in 2017, I test the hypothesis that individuals tend to like content that confirms their beliefs. I measure the political preferences of nearly 1.4 million users who were active on the main political and news media pages and classify them as being supporters of certain political organisations or as being politically unaffiliated. Based on the principles of analytical sociology, I construct a theoretical model that may explain the results. According to the model, users tend to like posts from only one source of information. There are also statistically significant differences in the news media preferences of supporters of different political organisations. They are prone to like posts published by sources that accord with their views. The model also correctly predicts that politically unaffiliated users choose media outlets that are considered unbiased or less biased. The results support the hypothesis that users of social media prefer exclusive or near-exclusive sources of information.
Źródło:
Polish Sociological Review; 2019, 206, 2; 177-198
1231-1413
2657-4276
Pojawia się w:
Polish Sociological Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Authentication in VoIP Telephony with Use of the Echo Hiding Method
Autorzy:
Rachoń, J.
Piotrkowski, Z.
Gajewski, P.
Powiązania:
https://bibliotekanauki.pl/articles/309527.pdf
Data publikacji:
2011
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
authentication
BS 1116-1 test
digital watermarking
echo hiding
Opis:
The paper describes the method intended to authenticate identity of a VoIP subscriber with use of the data hiding technique that is specifically implemented by means of the echo hiding method. The scope includes presentation of experimental results related to transmission of information via a hidden channel with use of the SIP/SDP signalling protocol as well as results of subjective assessment on quality of a signal with an embedded watermark.
Źródło:
Journal of Telecommunications and Information Technology; 2011, 1; 17-21
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of ultrasound to noninvasive imaging of temperature distribution induced in tissue
Autorzy:
Karwat, P.
Kujawska, T.
Secomski, W.
Gambin, B.
Litniewski, J.
Powiązania:
https://bibliotekanauki.pl/articles/332286.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
HIFU
echo phase shift
parametric imaging
velocity/brightness CNR
Opis:
Therapeutic and surgical applications of High Intensity Focused Ultrasound (HIFU) require monitoring of local temperature rises induced inside tissues. It is needed to appropriately target the focal plane, and hence the whole focal volume inside the tumor tissue, prior to thermo-ablative treatment, and the beginning of tissue necrosis. In this study we present an ultrasound method, which calculates the variations of the speed of sound in the locally heated tissue. Changes in velocity correspond to temperature change. The method calculates a 2D distribution of changes in the sound velocity, by estimation of the local phase shifts of RF echo-signals backscattered from the heated tissue volume (the focal volume of the HIFU beam), and received by an ultrasound scanner (23). The technique enabled temperature imaging of the heated tissue volume from the very inception of heating. The results indicated that the contrast sensitivity for imaging of relative changes in the sound speed was on the order of 0.06%; corresponding to an increase in the tissue temperature by about 2 °C.
Źródło:
Hydroacoustics; 2016, 19; 219-228
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of sound extinction and echo interference in densely aggregated zooplankton
Autorzy:
Gorska, N.
Powiązania:
https://bibliotekanauki.pl/articles/48619.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
fish
zooplankton
aggregation
hydroacoustic measurement
extinction
echo interference
krill
evaluation
Opis:
The investigation of sound extinction and echo interference is important as regards the accurate assessment of the abundance of densely aggregated zooplankton. To study these effects, the analytical model describing sound backscattering by an aggregation of isotropic scatterers (Rytov et al. 1978, Sun & Gimenez 1992) has been extended to the case of densely aggregated elongated zooplankton. The evaluation of the effects in the case of a dense krill aggregation demonstrates that they can be significant and should be taken into account.
Źródło:
Oceanologia; 2000, 42, 3
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Model-Based Method for Acoustic Echo Cancelation and Near-End Speaker Extraction: Non-negative Matrix Factorization
Autorzy:
Agrawal, P.
Shandilya, M.
Powiązania:
https://bibliotekanauki.pl/articles/958086.pdf
Data publikacji:
2018
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
adaptive algorithms
convergence
echo cancellation
non-negative matrix factorization (NMF)
Opis:
Rapid escalation of wireless communication and hands-free telephony creates a problem with acoustic echo in full-duplex communication applications. In this paper a simulation of model-based acoustic echo cancelation and near-end speaker extraction using statistical methods relying on nonnegative matrix factorization (NMF) is proposed. Acoustic echo cancelation using the NMF algorithm is developed and its implementation is presented, along with all positive, real time elements and factorization techniques. Experimental results are compared against the widely used existing adaptive algorithms which have a disadvantage in terms of long impulse response, increased computational load and wrong convergence due to change in near-end enclosure. All these shortcomings have been eliminated in the statistical method of NMF that reduces echo and enhances audio signal processing.
Źródło:
Journal of Telecommunications and Information Technology; 2018, 2; 15-22
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
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