445 research outputs found
Discriminator aided phase lock acquisition for suppressed carrier signals
A discriminator aided technique for acquisition of phase lock to a suppressed carrier signal utilizes a Costas loop which is initially operated open loop and control voltage for its VCXO is derived from a phase detector that compares the VCXO to a reference frequency thus establishing coarse frequency resolution with the received signal. Then the Costas loop is closed with the low-pass filter of the channel having a bandwidth much greater (by a factor of about 10) than in the I channel so that a frequency discriminator effect results to aid carrier resolution. Finally, after carrier acquisition, the Q-channel filter of the Costas loop is switched to a bandwidth substantially equal to that of the I-channel for carrier tracking
Baseband version of the bat-inspired spectrogram correlation and transformation receiver
Echolocating bats have evolved an excellent ability to detect and discriminate targets in highly challenging environments. They have had more than 50 million years of evolution to optimise their echolocation system with respect to their surrounding environment. Behavioural experiments have shown their exceptional ability to detect and classify targets even in highly cluttered surroundings. The way bats process signals is not exactly the same as in radar and hence it can be useful to investigate the differences. The Spectrogram Correlation And Transformation receiver (SCAT) is an existing model of the bat auditory system that takes into account the physiology and underlying neural organisation in bats which emit chirped signals. In this paper, we propose a baseband receiver equivalent to the SCAT. This will allow biologically inspired signal processing to be applied to radar baseband signals. It will also enable further theoretical analysis of the key concepts, advantages and limitations of the "bat signal processing" for the purpose of target detection, localisation and resolution. The equivalence is demonstrated by comparing the output of the original SCAT to that of our proposed baseband version using both simulated and experimental target echoes. Results show that the baseband receiver provides compatible frequency interference pattern for two closely located scatterers
Biologically inspired processing of radar and sonar target echoes
Modern radar and sonar systems rely on active sensing to accomplish a variety of tasks, including detection and classification of targets, accurate localization and tracking, autonomous navigation and collision avoidance. Bats have relied on active sensing for over 50 million years and their echolocation system provides remarkable perceptual and navigational performance that are of envy to synthetic systems.
The aim of this study is to investigate the mechanisms bats use to process echo acoustic signals and investigate if there are lessons that can be learned and ultimately applied to radar systems. The basic principles of the bat auditory system processing are studied and applied to radio frequencies.
A baseband derivative of the Spectrogram Correlation and Transformation (SCAT) model of the bat auditory system, called Baseband SCAT (BSCT), has been developed. The BSCT receiver is designed for processing radio-frequency signals and to allow an analytical treatment of the expected performance. Simulations and experiments have been carried out to confirm that the outputs of interest of both models are βequivalentβ.
The response of the BSCT to two closely spaced targets is studied and it is shown that the problem of measuring the relative distance between two targets is converted to a problem of measuring the range to a single target. Nearly double improvement in the resolution between two close scatterers is achieved with respect to the matched filter.
The robustness of the algorithm has been demonstrated through laboratory measurements using ultrasound and radio frequencies (RF). Pairs of spheres, flat plates and vertical rods were used as targets to represent two main reflectors
Baseband version of the bat-inspired spectrogram correlation and transformation receiver
Poster presentation at the 2016 Defence and Security Doctoral Symposium. Echolocating bats have evolved an excellent ability to detect, resolve and discriminate targets in highly challenging environments. They have had more than 50 million years of evolution to optimise their echolocation system and behavioural experiments have shown their exceptional ability to detect and classify targets even in highly cluttered surroundings. Behavioural experiments have demonstrated that bats are able to resolve closely located scatterers: β’a two-point resolution of 2Γ·10 ΞΌs with waveforms of a bandwidth of 85 kHz (Eptesicus fuscus) β’ discriminate between two phantom target echoes separated by a time-delay of about 1Β ΞΌs with waveforms of a bandwidth of up to 100 kHz (Megaderma lyra) β’higher range resolution performance with respect to the conventional matched filter. The way bats process target echoes is different from the standard processing techniques used in radar and sonar, and there may be lessons to learn by investigating differences and similarities. The Spectrogram Correlation And Transformation receiver (SCAT) is an existing model of the bat auditory system that takes into account the physiology and underlying neural organisation in bats that emit chirped signals. The aims of this work are: β’develop a baseband receiver equivalent to the SCAT to Β Β - allow the application of biologically inspired signal processing to radar baseband signalsΒ - enable further theoretical analysis of the key concepts, advantages and limitations of the βbat signal processingβ β’carry out simulations and experimen ts to investigate differences and similarities between the output (the frequency interference pattern for two closely located scatterers) of the original SCAT and that of the proposed baseband version
Bio-inspired two target resolution at radio frequencies
Echolocating bats show a unique ability to detect, resolve and discriminate targets. The Spectrogram Correlation and Transformation (SCAT) receiver is a model of the Eptesicus fuscus auditory system that presents key signal processing differences compared to radar which may offer useful lessons for improvement. A baseband version of the SCAT is used to investigate advantages and disadvantages of bat-like signal processing against the task of target resolution. The baseband receiver is applied to RF experimental data and results show higher range resolution than the reciprocal of the transmitted bandwidth can be achieved for two closely spaced scatterers
Bio-inspired processing of radar target echoes
Echolocating bats have evolved the ability to detect, resolve and discriminate targets in highly challenging environments using biological sonar. The way bats process signals in the receiving auditory system is not the same as that of radar and sonar and hence investigating differences and similarities might provide useful lessons to improve synthetic sensors. The Spectrogram Correlation And Transformation (SCAT) receiver is an existing model of the bat auditory system that takes into account the physiology and the neural organisation of bats that emit broadband signals. In this study, the authors present a baseband receiver equivalent to the SCAT that allows an analysis of target echoes at baseband. The baseband SCAT (BSCT) is used to investigate the output of the bat-auditory model for two closely spaced scatterers and to carry out an analysis of range resolution performance and a comparison with the conventional matched filter. Results firstly show that the BSCT provides improved resolution performance. It is then demonstrated that the output of the BSCT can be obtained with an equivalent matched-filter based receiver. The results are verified with a set of laboratory experiments at radio frequencies in a high signal-to-noise ratio
Sacred experience and place in cities.
Massachusetts Institute of Technology. Dept. of Urban Studies and Planning. Thesis. 1972. M.C.P.Bibliography: leaves 104-106.M.C.P
Choreographic memory: research of choreographic folk practice in popular culture
ΠΠΎΠΊΡΠΎΡΡΠΊΠ° Π΄ΠΈΡΠ΅ΡΡΠ°ΡΠΈΡΠ° ΠΠΎΡΠ΅ΠΎΠ³ΡΠ°ΡΡΠΊΠ° ΠΌΠ΅ΠΌΠΎΡΠΈΡΠ°: ΠΈΡΡΡΠ°ΠΆΠΈΠ²Π°ΡΠ΅ ΠΊΠΎΡΠ΅ΠΎΠ³ΡΠ°ΡΡΠΊΠ΅ Π½Π°ΡΠΎΠ΄Π½Π΅ ΠΏΡΠ°ΠΊΡΠ΅ Ρ ΠΏΠΎΠΏΡΠ»Π°ΡΠ½ΠΎΡ ΠΊΡΠ»ΡΡΡΠΈ ΡΡΠΌΠ΅ΡΠ΅Π½Π° ΡΠ΅ Π½Π°jΠΏΡΠ΅ Π½Π° ΡΡΠΏΠΎΡΡΠ°Π²ΡΠ°ΡΠ΅ ΠΈ Π΄Π΅ΡΠ΅ΡΠΌΠΈΠ½ΠΈΡΠ°ΡΠ΅ ΠΊΠΎΠ½ΡΠ΅ΠΏΡΠ° ΠΊΠΎΡΠ΅ΠΎΠ³ΡΠ°ΡΡΠΊΠ° ΠΌΠ΅ΠΌΠΎΡΠΈΡΠ°. Π’Π΅ΡΠΌΠΈΠ½ ΠΊΠΎΡΠ΅ΠΎΠ³ΡΠ°ΡΡΠΊΠ° ΠΌΠ΅ΠΌΠΎΡΠΈΡΠ° Ρ ΠΎΠ²ΠΎΠΌ ΡΠ°Π΄Ρ ΡΠ΅ ΡΡΠ΅ΡΠΈΡΠ° ΠΊΠ°ΠΎ ΡΠ΅Π½ΠΎΠΌΠ΅Π½ ΠΊΠΎΡΠΈ ΡΠ΅ ΠΎΠ΄Π²ΠΈΡΠ° ΠΊΠΎΠ΄ ΠΈΠ·Π²ΠΎΡΠ°ΡΠ° ΠΊΠΎΡΠ΅ΠΎΠ³ΡΠ°ΡΠΈΡΠ΅ Π½Π°ΡΠΎΠ΄Π½Π΅ ΠΈΠ³ΡΠ΅ ΠΊΠ°ΠΎ ΠΏΠΎΡΠ΅Π΄ΠΈΠ½ΡΠ°, Π° Π·Π°ΡΠΈΠΌ ΠΈ ΠΊΠ°ΠΎ Π΄Π΅ΠΎ ΠΊΠΎΠ»Π΅ΠΊΡΠΈΠ²Π° Ρ ΠΊΠΎΡΠ΅ΠΌ ΡΠ΅ Ρ Π½Π΅ΡΠ°ΡΠΊΠΈΠ΄ΠΈΠ²ΠΎΠΌ ΡΠΈΠ½ΠΊΡΠ΅ΡΠΈΡΠΊΠΎΠΌ ΡΠ΅Π΄ΠΈΠ½ΡΡΠ²Ρ ΠΎΠ±ΡΠ΅Π΄ΠΈΡΠ΅Π½ΠΎ Π²ΠΈΡΠ΅ ΡΠ°Π·Π»ΠΈΡΠΈΡΠΈΡ
ΠΊΠΎΡΠ΅ΠΎΠ³ΡΠ°ΡΡΠΊΠΈΡ
Π΅Π»Π΅ΠΌΠ΅Π½Π°ΡΠ° (ΠΊΠΈΠ½Π΅ΡΠΈΠΊΠ°, ΠΏΡΠΎΡΡΠΎΡ, ΠΌΡΠ·ΠΈΠΊΠ°, Π²ΡΠ΅ΠΌΠ΅ ΠΈ Π΅ΠΊΡΠΏΡΠ΅ΡΠΈΡΠ°).
Π£ΡΠΏΠΎΡΡΠ°Π²ΡΠ°ΡΠ΅ ΠΊΠΎΠ½ΡΠ΅ΠΏΡΠ° ΠΊΠΎΡΠ΅ΠΎΠ³ΡΠ°ΡΡΠΊΠ° ΠΌΠ΅ΠΌΠΎΡΠΈΡΠ° Π·Π°Ρ
ΡΠ΅Π²Π° ΠΊΠΎΠΌΠΏΠ»Π΅ΠΊΡΠ°Π½ ΠΈ ΠΈΠ½ΡΠ΅ΡΠ΄ΠΈΡΡΠΈΠΏΠ»ΠΈΠ½Π°ΡΠ°Π½ ΠΏΡΠΈΡΡΡΠΏ, ΠΏΡΠ΅ ΡΠ²Π΅Π³Π° Π·Π°ΡΠΎ ΡΡΠΎ ΡΠ΅ ΡΠ΅Ρ ΠΎ ΠΊΠΎΠ½ΡΠ΅ΠΏΡΡ ΠΊΠΎΡΠΈ Π½ΠΈΡΠ΅ Ρ Π΄ΠΎΡΠ°Π΄Π°ΡΡΠΈΠΌ ΡΡΡΠ΄ΠΈΡΠ°ΠΌΠ° ΠΏΠ»Π΅ΡΠ°, Π½Π°ΡΠ°ΠΎ ΡΠ²ΠΎΡΠ΅ Π·Π½Π°ΡΠ°ΡΠ½ΠΈΡΠ΅ ΠΌΠ΅ΡΡΠΎ Ρ ΠΈΡΡΡΠ°ΠΆΠΈΠ²Π°ΡΠΈΠΌΠ°. ΠΠΏΠ°ΠΊ, ΠΊΠΎΡΠ΅ΠΎΠ³ΡΠ°ΡΡΠΊΠ° ΠΌΠ΅ΠΌΠΎΡΠΈΡΠ° ΠΌΠΎΠΆΠ΅ ΡΠ΅ ΡΠ΅ΡΠΈ Π΄Π° ΠΈΠΌΠ° ΡΠ²ΠΎΡΡ ΠΈΡΡΠΎΡΠΈΡΡΠΊΠΈ ΠΊΠΎΠ½ΡΠΈΠ½ΡΠΈΡΠ°Π½Ρ ΠΏΡΠΈΡΡΡΠ½ΠΎΡΡ ΠΎΠ΄ ΠΌΠΎΠΌΠ΅Π½ΡΠ° ΠΊΠ°Π΄Π° ΡΡ ΡΠ΅ Π½Π°ΡΠΎΠ΄Π½Π΅ ΠΈΠ³ΡΠ΅ ΠΏΠΎΡΠ΅Π»Π΅ ΠΊΠΎΡΠ΅ΠΎΠ³ΡΠ°ΡΡΠΊΠΈ ΠΎΠ±Π»ΠΈΠΊΠΎΠ²Π°ΡΠΈ ΠΈ ΠΊΠ°ΠΎ ΡΠ°ΠΊΠ²Π΅ ΡΡΠΈΡΠΈ, ΡΠ²Π΅ΠΆΠ±Π°Π²Π°ΡΠΈ ΠΈ ΠΏΠ°ΠΌΡΠΈΡΠΈ, ΡΡΠΎ ΡΠ΅ ΠΎΠ΄Π²ΠΈΡΠ°Π»ΠΎ Ρ Π½Π°ΠΌΠ΅Π½ΡΠΊΠΈΠΌ ΠΏΡΠΎΡΡΠΎΡΠΈΡΠ°ΠΌΠ° Π·Π° ΠΏΡΠΎΠ±Π΅, Π΄Π° Π±ΠΈ ΡΠ΅ ΡΠ°Π²Π½ΠΎ ΠΈΠ·Π²Π΅Π»Π΅ ΠΈ ΠΏΡΠΈΠΊΠ°Π·Π°Π»Π΅ Π½Π° ΡΡΠ΅Π½ΠΈ ΠΏΡΠ΅Π΄ ΠΏΡΠ±Π»ΠΈΠΊΠΎΠΌ. Π’ΠΎ Π·Π½Π°ΡΠΈ Π΄Π° ΡΠ΅ ΠΊΠΎΡΠ΅ΠΎΠ³ΡΠ°ΡΡΠΊΠ° ΠΌΠ΅ΠΌΠΎΡΠΈΡΠ° ΡΠ°Π²ΡΠ΅ΠΌΠ΅Π½Π° ΠΈ Π°ΠΊΡΡΠ΅Π»Π½Π° Ρ ΡΠ²Π°ΠΊΠΎΠΌ ΠΏΠ΅ΡΠΈΠΎΠ΄Ρ ΠΈΡΡΠΎΡΠΈΡΡΠΊΠΎΠ³ ΡΠ°Π·Π²ΠΈΡΠΊΠ° Π½Π΅ ΡΠ°ΠΌΠΎ Ρ ΠΎΠ±Π»Π°ΡΡΠΈ ΠΊΠΎΡΠ΅ΠΎΠ³ΡΠ°ΡΠΈΡΠ΅ Π½Π°ΡΠΎΠ΄Π½ΠΈΡ
ΠΈΠ³Π°ΡΠ°, Π²Π΅Ρ ΡΠΎΠΏΡΡΠ΅Π½ΠΎ ΠΎΠ΄ ΠΊΠ°Π΄Π° ΡΠ΅ ΠΏΠΎΡΠ΅Π»Π° Π΄Π° ΡΠ΅ ΠΎΠ±Π»ΠΈΠΊΡΡΠ΅ ΠΊΠΎΡΠ΅ΠΎΠ³ΡΠ°ΡΡΠΊΠ° ΡΠΎΡΠΌΠ° Ρ ΡΠΌΠ΅ΡΠ½ΠΈΡΠΊΠΎΡ ΠΈΠ³ΡΠΈ.
Π’Π΅ΠΌΠ΅ΡΠ½Π° ΠΏΠΎΠ»Π°Π·ΠΈΡΡΠ° Π·Π° ΡΡΠΏΠΎΡΡΠ°Π²ΡΠ°ΡΠ΅ ΠΊΠΎΠ½ΡΠ΅ΠΏΡΠ° ΠΊΠΎΡΠ΅ΠΎΠ³ΡΠ°ΡΡΠΊΠ° ΠΌΠ΅ΠΌΠΎΡΠΈΡΠ° Ρ ΠΎΠ²ΠΎΠΌ ΡΠ°Π΄Ρ ΡΠ΅ ΠΎΡΠ»Π°ΡΠ°ΡΡ Π½Π° Π°Π½Π°Π»ΠΈΠ·Ρ ΠΈ ΠΈΠ½ΡΠ΅ΡΠΏΡΠ΅ΡΠ°ΡΠΈΡΡ Π²Π΅Π·Π΅ ΠΌΡΠ·ΠΈΠΊΠ΅ ΠΈ ΠΏΠΎΠΊΡΠ΅ΡΠ° Ρ ΠΊΠΎΡΠ΅ΠΎΠ³ΡΠ°ΡΡΠΊΠΎΡ Π½Π°ΡΠΎΠ΄Π½ΠΎΡ ΠΏΡΠ°ΠΊΡΠΈ Ρ ΠΏΠΎΠΏΡΠ»Π°ΡΠ½ΠΎΡ ΠΊΡΠ»ΡΡΡΠΈ. ΠΡΠ½ΠΎΠ²Π½Π° ΡΡΠΌΠ΅ΡΠ΅ΡΠ° ΡΡ Π±ΠΈΠ»Π° ΠΏΠΈΡΠ°ΡΠ° Ρ Π΄ΠΎΠΌΠ΅Π½Ρ ΠΊΠΎΠ³Π½ΠΈΡΠΈΠ²Π½ΠΎΠ³ ΠΏΡΠΈΡΡΡΠΏΠ°. ΠΠ½ΠΊΠΎΡΠΏΠΎΡΠΈΡΠ°ΡΠ΅ ΠΊΠΎΠ³Π½ΠΈΡΠΈΠ²Π½ΠΈΡ
ΠΈΡΡΡΠ°ΠΆΠΈΠ²Π°ΡΠ° Ρ Π΄ΠΎΠΌΠ΅Π½ ΡΡΡΠ΄ΠΈΡΠ΅ ΠΏΠ»Π΅ΡΠ° ΡΡΠ²Π°ΡΠ° ΠΏΠ»ΠΎΠ΄ΠΎΠ½ΠΎΡΠ½ΠΎ ΡΠ»ΠΎ ΠΊΠΎΡΠ΅ ΠΏΠΎΡΠΏΠ΅ΡΡΡΠ΅ (ΠΏΡΠ΅)ΠΈΡΠΏΠΈΡΠΈΠ²Π°ΡΠ΅ Π΄ΠΎΡΠ°Π΄Π°ΡΡΠΈΡ
Π΄ΠΎΠ³ΠΌΠΈ ΠΎ ΠΎΠ΄Π½ΠΎΡΡ ΠΌΡΠ·ΠΈΠΊΠ΅ ΠΈ ΠΈΠ³ΡΠ΅, ΠΊΠ°ΠΎ ΠΈ ΠΏΠΎΡΡΠ΅Π±Ρ Π·Π° Π±ΡΠ΄ΡΡΠΈΠΌ ΠΈΠ½ΡΠ΅ΡΠ΄ΡΠΈΡΠΈΠΏΠ»ΠΈΠ½Π°ΡΠ½ΠΈΠΌ ΠΈΡΡΡΠ°ΠΆΠΈΠ²Π°ΡΠΈΠΌΠ° ΠΏΡΠΎΡΠ΅ΡΠ° ΡΡΠ΅ΡΠ° ΠΈ ΠΏΠ°ΠΌΡΠ΅ΡΠ° ΠΊΠΎΡΠ΅ΠΎΠ³ΡΠ°ΡΠΈΡΠ΅ ΠΊΠ°ΠΎ ΡΠΌΠ΅ΡΠ½ΠΈΡΠΊΠ΅ ΡΠΎΡΠΌΠ΅.
ΠΠΎΠ½ΡΠ΅ΠΏΡ ΠΊΠΎΡΠ΅ΠΎΠ³ΡΠ°ΡΡΠΊΠ° ΠΌΠ΅ΠΌΠΎΡΠΈΡΠ° ΡΡΡΡΠΊΡΡΡΠΈΡΠ°Π½ Π½Π° ΠΎΠ²Π°Ρ Π½Π°ΡΠΈΠ½ ΠΏΠΎΡΡΠ°ΡΠ΅ ΠΏΡΠ΅Π΄ΠΌΠ΅Ρ ΠΏΠ»Π΅ΡΠ½ΠΎΠ³ Π½Π°ΡΡΠ½ΠΎΠ³ Π΄ΠΈΡΠΊΡΡΡΠ° ΡΠΈΡΠΈ ΡΠ΅ ΡΠΌΠΈΡΠ°ΠΎ, Π·Π½Π°ΡΠ΅ΡΠ΅ ΠΈ Π²ΡΠ΅Π΄Π½ΠΎΡΡ ΠΎΡΡΠ²Π°ΡΡΡΠ΅ Ρ ΠΈΠ½ΡΠ΅ΡΡΠ΅ΠΊΡΡΡΠ°Π»Π½ΠΎΡΡΠΈ ΡΠ°Π·Π»ΠΈΡΠΈΡΠ΅ ΠΏΡΠΈΡΠΎΠ΄Π΅
(ΠΡΠ΅)ΠΈΡΠΏΠΈΡΠΈΠ²Π°ΡΠ΅ ΠΎΠ΄Π½ΠΎΡΠ° ΠΌΡΠ·ΠΈΠΊΠ΅ ΠΈ ΠΈΠ³ΡΠ΅ ΠΈΠ· ΠΏΠ΅ΡΡΠΏΠ΅ΠΊΡΠΈΠ²Π΅ ΡΡΠ΅ΡΠ° ΠΈ ΠΏΠ°ΠΌΡΠ΅ΡΠ° ΠΊΠΎΡΠ΅ΠΎΠ³ΡΠ°ΡΠΈΡΠ΅ Π½Π°ΡΠΎΠ΄Π½Π΅ ΠΈΠ³ΡΠ΅
This article contributes to the study of the relationship between music and dance through the elaboration of questions such as: how music and dance coexist in the perception of the performer; whether dance is always inseparable from music or it becomes independent from it in formal learning conditions; whether music influences learning and memorising the choreography of the folk dance. Incorporating aspects of cognitive research into the study fields of ethnomusicology and ethnochoreology creates fertile ground for (re)examining previous opinions about the relationship between music and dance, as well as the need for future interdisciplinary research of the process of learning and remembering choreography as an art form
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