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An analysis of phonotactic behaviour in the cricket Gryllus bimaculatusSarmiento-Ponce, Edith Julieta January 2019 (has links)
This thesis represents a comprehensive examination of the phonotactic behaviour (i.e. attraction to sound) of the female Gryllus bimaculatus under laboratory conditions. Chapter 2 is the first study to analyze the effect of substrate texture on walking performance in crickets. Substrate texture is found to play an essential role in the phonotactic responses of G. bimaculatus. Smooth substrate texture has a detrimental effect due to slipping, whereas a rough texture results in optimal walking performance due to the friction with the walking legs. Chapter 3 represents the first detailed lifetime study analysing phonotaxis in crickets. My results demonstrate that the optimal age to test phonotaxis in G. bimaculatus females is from day 7 to 24 after the final moult. I also found that selectiveness was persistent with age. These findings contradict the female choosiness hypothesis. This study is also the first to describe the effect of senescence on phonotaxis in insects, as responsiveness decreases with age. Chapter 4 compares the phonotactic behaviour of female crickets from different laboratory-bred colonies. From six tested cricket lab colonies, I found three groups statistically different from each other. Females raised under laboratory conditions at the University of Cambridge and Anglia Ruskin University were most reponsive at a frequency of 4.5 kHz, whereas females bred in Tokushima University in Japan were tuned towards a higher frequency of 5 kHz. These results suggest a degree of artificial allopatric speciation. Comparisons with crickets bred under low-quality conditions in a local pet shop demonstrate a loss of responsiveness, indicating that breeding conditions have a direct effect on phonotactic responsivity. Chapter 5 is the first study to report the presence of phonotaxis in males of G. bimaculatus. Previously it was unknown if G. bimaculatus males were able to perform phonotaxis, given that they were only recognised as endurance signal producers. In the present study, only 20% of the studied males (N=70) performed a weak phonotactic response. This finding has potential ecological implications in terms of male cricket territory establishment, and male-male interactions in the wild, which are discussed. Chapter 6 explores the song pattern recognition of the female G. bimaculatus by changing the duration of either the first, second or third pulse of the chirps. A long first pulse decreased the phonotactic response whereas phonotaxis remained strong when the third pulse was long. Chirps with three pulses of increasing duration of 5, 20 and 50 ms elicited phonotaxis, but the chirps were not attractive when played in reverse order. The data are in agreement with a mechanism in which processing of a sound pulse has an effect on the processing of the subsequent pulse, as outlined in the flow of activity in a delay-line and coincidence-detector circuit.
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Etude et développement de capteurs tactiles flexibles à détection harmonique vers la fonctionnalisation sensitive des surfaces / Study and development of harmonic detection flexible sensors for sensitive functionalisation of surfacesSelmene ep Ben Hassine, Nissem 05 December 2016 (has links)
L’avènement des interfaces tactiles ouvre des perspectives d’enrichissement de l’interaction entre l’homme et la machine. Nous proposons un nouveau concept de surfaces tactiles souples dont l’objectif est d’étudier l’interaction entre le signal électrique et l’environnement résistif et diélectrique du support, afin de réaliser le système d’acquisition fournissant une information exploitable par la machine.La base technologique est un guide d’ondes sur substrat souple sur lequel le toucher crée une réflexion au port d’entrée. Nous avons développé une méthode de localisation alternative à la réflectométrie temporelle, nommée Harmonic Detection and Location (HDL), permettant l’utilisation d’une électronique d’acquisition de faible complexité, en bande étroite, autour de 100 MHz. Le concept a été validé à partir de mesures sur des dalles tactiles souples et rigides connectées à un analyseur de réseau, utilisé comme référence. Un système d’acquisition compact basé sur un pont de Wheatstone associé à un détecteur de phase a été développé. Pour ce faire, un travail de caractérisation et d’identification des sources d’erreurs a été mené sur les interactions électromagnétiques entre le doigt et le guide d’onde, les imperfections du guide d’onde et la nature du substrat ainsi que l’impact des erreurs induites par l’électronique d’acquisition.Cette connaissance a permis de co-développer la partie matérielle et l’algorithme de détection pour démontrer une précision de localisation de 2cm. Les fondamentaux posés dans ce travail ouvrent la possibilité de réalisation d’interfaces de grande surface, avec une connectique simple, conformables sur des objets sensitifs en trois dimensions / The advent of sensitive interfaces is promising prospects to the human-machine interaction. We propose a new concept of sensitive flexible surface. Its aim is to study the interaction between electrical signal and resistive and dielectric environment of the support in order to realize an acquisition system providing machine readable information.The technological base is a waveguide on flexible substrate on which the touch creates a reflection at the input port. We have developed a location method as an alternative to the time domain reflectometry (TDR). It is named Harmonic Detection and Location (HDL) and it allows using a narrow band, around 100 MHz, low complexity acquisition system. The concept has been approved using measures on flexible and rigid sensitive surfaces connected to a vector network analyzer (VNA) used as reference. A compact acquisition system based on a Wheatstone bridge associated to a phase detector has been developed. For this purpose, errors characterization and identification work has been done. Electromagnetic interactions between the finger and the waveguide, waveguide imperfections, substrate nature and acquisition system errors’ impact have been studied. This knowledge has provided the possibility to co-develop the hardware and the detection algorithm to demonstrate a location accuracy of 2cm. Fundamental principles of this work provide the possibility of realizing large surface interfaces, with simple connection and conformable, for 3D sensitive objects.
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