Dissertations / Theses on the topic 'Vibrational communication'

Thesis (Ph. D.)--University of Missouri-Columbia, 2007.
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on February 25, 2008) Vita. Includes bibliographical references.

The component that generates the frequency of the radio waves transmitted by a radar is generally built around a quartz crystal oscillator. When this component is exposed to mechanical vibrations, such as acceleration or rotation in different directions, phase noise occurs. That is due to the piezoelectric effect of quartz crystals, which eventually degrades the performance of a radar. High frequency noise are compensated for using mechanical dampers. However, the low frequency noise remains and requires a digital solution. To solve this, a theoretical compensation model for the quartz crystal has been designed. It was possible to measure the noise generated by the quartz crystal by utilising an accelerometer, perform simulations and calculations. With the help of these different tools, it was possible to theoretically calculate and reduce the phase noise by 30-40%. All the results that has been obtained are theoretical results and nothing has yet been implemented in any radar system.

Thesis (M.S.)--State University of New York at Binghamton, Thomas J. Watson School of Engineering and Applied Science, Department of Electrical and Computer Engineering, 2009.
Includes bibliographical references.

Störningar som damm, buller och vibrationer förekommer vid alla byggarbeten. Detta skapar problem vid byggnation av sjukhus med pågående verksamhet. Stockholms sjukhus uppfyller inte samhällets växande behov på hälso- och sjukvård. Stora investeringar görs därför för att rusta upp sjukhusen, Södertälje sjukhus är det första att moderniseras [2]. Examensarbetet undersöker vilka störningar som vårdpersonalen vid Södertälje sjukhus upplever och vad Locum samt Södertälje Sjukhus AB gör för att reducera dessa. Observationer, möten och litteraturstudier genomfördes för att samla information om Södertälje sjukhus, Locum och byggrelaterade störningar. En enkätundersökning utfördes för att få kunskap om vårdens åsikter gällande kommunikation, störningar och evakuering av verksamhet. Med detta som underlag genomfördes analysering som resulterade i åtgärdsförslag för reducering av vårdens upplevda störningar. Analysen visade att vården upplevt flera störningar från byggnationerna, störst påverkan hade buller och vibrationer. Vårdens inställning och förståelse till byggnationerna var god. God informering via flera kommunikationskanaler ligger till grund för detta. Vidare utveckling av kommunikationskanalerna skulle reducera den upplevda störningen.
Disturbances such as dust, noise and vibrations occur in all construction work. This creates problems in the construction of hospitals with ongoing activities. The hospitals in Stockholm do not meet society's growing need for health care. Huge investments are therefore made to rehabilitate the hospitals, Södertälje Hospital is the first to be modernized [2]. This thesis investigates the perceived disturbances that healthcare personnel experience at Södertälje hospital and what Locum and Södertälje Sjukhus AB do to reduce them. Observations, meetings and literature studies were conducted to gather information about Södertälje Hospital, Locum and construction-related disturbances. A survey was conducted to gain knowledge about the opinions of healthcare personnel regarding communication, disturbances and evacuation operations. An analysis was conducted on this basis, which resulted in proposed measures for reducing perceived disturbance by healthcare. The analysis showed that the healthcare experienced several disturbances from construction work, noise and vibrations had the greatest impact. Personnel’s attitude and understanding to the construction work was good. Good informing shared through multiple communication channels is the basis for this. Further development of communication channels would reduce the perceived disturbance.

Un nombre croissant d’appareils électroniques portatifs et portables entraîne une demande croissante de module d’alimentation électrique durable et localisé de petite taille et de poids, et offrant une puissance de sortie élevée. En tant que choix prometteur pour l’alimentation électrique, les moissonneuses d’énergie cinétiques (REC), qui transforment les vibrations ou les mouvements ambiants en énergie électrique, sont étudiées de manière intensive ces dernières années. Les performances des RECs miniatures disponibles dans la littérature sont généralement limitées par leur taille. Les vibrations ambiantes sont généralement abondantes en basse fréquence, ce qui est également un facteur majeur limitant la puissance de sortie du REC. Afin d’améliorer la puissance de sortie, nous devrions améliorer l’efficacité de la conversion d’énergie, qui est liée au principe de transduction. Ce travail présente l’amélioration de la puissance de sortie des RECs électrostatiques basse fréquence grâce à un mécanisme de conversion de fréquence mécanique couplé par impact, et propose un modèle numérique prédictif du prototype qui prend en compte l’effet d’amortissement de l’air et les impacts dans le prototype. Un prototype est proposé avec une géométrie améliorée du module capacitif réduisant la force d’amortissement de l’air. Des approches alternatives pour ajuster les RECs à des applications variées sont proposées, y compris un REC entièrement flexible conçue pour l’électronique portable, et un REC à basse fréquence 2-D sensible aux vibrations suivant deux directions orthogonales. De plus, un système d’étiquette RFID entièrement autonome en énergie mettant en œuvre le REC à basse fréquence en tant que module d’alimentation électrique et un module de communication RFID semi-passif est présenté
A growing number of portable and wearable electronics results in an increasing demand of sustainable and localized power supply module of small size and weight, and offering high output power. As a promising choice for the power supply, Kinetic energy harvesters (KEHs), transforming the ambient vibrations or motions into electrical energy, are studied intensively in recent yeas. The performance of the miniature KEHs available in literature are generaly confined by their sized. The ambient vibrations are usually abundant in low frequency, which is also a major factor restricting the output power of the KEH. In order to enhance the power output, we should improve the energy conversion efficiency, which is related to the transduction principle. This work presents the improvement of the output power of low frequency electrostatic KEHs through impact-coupled mechanical frequency up conversion mechanism, and proposes a predictive numerical model of the prototype which considers the squeeze film air damping effect and the impacts in the prototype. A prototype is proposed with improved geometry of capacitive module reducing the air damping force. Alternative approaches to adjust the KEHs to varied applications are proposed, including a fully flexible KEH designed for wearable electronics, and a 2-D low frequency KEH that is sensible to vibrations along two orthogonal directions. In addition, a fully energy-autonomous RFID tag system implementing the low frequency KEH as the power supply module and a semi-passive RFID communication module is presented

While substrate-borne vibrations are utilized by different reptile species, true conspecific communication via biotremors has not yet been demonstrated in reptiles. This study follows a preliminary report that the veiled chameleon (Chamaeleo calyptratus) could produce biotremors in communicative contexts. I tested chameleon behavioral sensitivity to vibrations by placing them on a dowel attached to a shaker emitting vibrations of 25, 50, 150, 300, and 600 Hz and then measured their changes in velocity before and after the stimulus. I then paired chameleons in various social contexts [anthropogenic disturbance (human disruption of animal); dominance (malemale; female-female C. calyptratus); courtship (male-female C. calyptratus); heterospecific (C. calyptratus + C. gracilis); and predator-prey (adult + juvenile C. calyptratus)] and used a video camera and accelerometers to record their behavior. This study demonstrates that chameleons produce biotremors and that receivers exhibit a freeze response when exposed to a simulated biotremor stimulus. Furthermore, veiled chameleons produce biotremors in anthropogenic disturbance, conspecific dominance and courtship contexts, and these biotremors are elicited by visual contact with another adult conspecific and heterospecifics. Overall, two classes of biotremor were identified, "hoots” and “rumbles,” which differ significantly in dominant frequency and waveform. No correlation was identified between animal size and dominant frequency of the biotremors they produced as biotremors originate from rapid muscle contractions. Juvenile chameleons of two months of age are able to produce biotremors, suggesting this behavior may have multiple functions. Overall, the data suggest that the veiled chameleon has the potential to utilize substrate-borne vibrational communication during conspecific and possibly heterospecific interactions.

Significant advances in wind turbine technology have increased the need for maintenance through condition monitoring. Indeed condition monitoring techniques exist and are deployed on wind turbines across Europe and America but are limited in scope. The sensors and monitoring devices used can be very expensive to deploy, further increasing costs within the wind industry. The work outlined in this thesis primarily investigates potential low-cost alternatives in the laboratory environment using vibration-based and modal testing techniques that could be used to monitor the condition of wind turbine blades. The main contributions of this thesis are: (1) the review of vibration-based condition monitoring for changing natural frequency identification; (2) the application of low-cost piezoelectric sounders with proof mass for sensing and measuring vibrations which provide information on structural health; (3) the application of low-cost miniature Micro-Electro-Mechanical Systems (MEMS) accelerometers for detecting and measuring defects in micro wind turbine blades in laboratory experiments; (4) development of an in-service calibration technique for arbitrarily positioned MEMS accelerometers on a medium-sized wind turbine blade. This allowed for easier aligning of coordinate systems and setting the accelerometer calibration values using samples taken over a period of time; (5) laboratory validation of low-cost modal analysis techniques on a medium-sized wind turbine blade; (6) mimicked ice-loading and laboratory measurement of vibration characteristics using MEMS accelerometers on a real wind turbine blade and (7) conceptualisation and systems design of a novel embedded monitoring system that can be installed at manufacture, is self-powered, has signal processing capability and can operate remotely. By applying the conclusions of this work, which demonstrates that low-cost consumer electronics specifically MEMS accelerometers can measure the vibration characteristics of wind turbine blades, the implementation and deployment of these devices can contribute towards reducing the rising costs of condition monitoring within the wind industry.

This thesis addresses a challenging problem: “how to let the visually impaired ‘see’ others emotions”. We, human beings, are heavily dependent on facial expressions to express ourselves. A smile shows that the person you are talking to is pleased, amused, relieved etc. People use emotional information from facial expressions to switch between conversation topics and to determine attitudes of individuals. Missing emotional information from facial expressions and head gestures makes the visually impaired extremely difficult to interact with others in social events. To enhance the visually impaired’s social interactive ability, in this thesis we have been working on the scientific topic of ‘expressing human emotions through vibrotactile patterns’. It is quite challenging to deliver human emotions through touch since our touch channel is very limited. We first investigated how to render emotions through a vibrator. We developed a real time “lipless” tracking system to extract dynamic emotions from the mouth and employed mobile phones as a platform for the visually impaired to perceive primary emotion types. Later on, we extended the system to render more general dynamic media signals: for example, render live football games through vibration in the mobile for improving mobile user communication and entertainment experience. To display more natural emotions (i.e. emotion type plus emotion intensity), we developed the technology to enable the visually impaired to directly interpret human emotions. This was achieved by use of machine vision techniques and vibrotactile display. The display is comprised of a ‘vibration actuators matrix’ mounted on the back of a chair and the actuators are sequentially activated to provide dynamic emotional information. The research focus has been on finding a global, analytical, and semantic representation for facial expressions to replace state of the art facial action coding systems (FACS) approach. We proposed to use the manifold of facial expressions to characterize dynamic emotions. The basic emotional expressions with increasing intensity become curves on the manifold extended from the center. The blends of emotions lie between those curves, which could be defined analytically by the positions of the main curves. The manifold is the “Braille Code” of emotions. The developed methodology and technology has been extended for building assistive wheelchair systems to aid a specific group of disabled people, cerebral palsy or stroke patients (i.e. lacking fine motor control skills), who don’t have ability to access and control the wheelchair with conventional means, such as joystick or chin stick. The solution is to extract the manifold of the head or the tongue gestures for controlling the wheelchair. The manifold is rendered by a 2D vibration array to provide user of the wheelchair with action information from gestures and system status information, which is very important in enhancing usability of such an assistive system. Current research work not only provides a foundation stone for vibrotactile rendering system based on object localization but also a concrete step to a new dimension of human-machine interaction.
Taktil Video

Vibratory communication has evolved in numerous animal groups, including insects, spiders, fishes, mammals, and was recently discovered in veiled chameleons (Chamaeleo calyptratus). I examined the mechanism by which C. calyptratus produce these biotremors. Muscle activity data were gathered during simulated anti-predator responses via electromyography (EMG) with simultaneous recordings of biotremor production using an accelerometer. I correlated EMG data with the accelerometer data to implicate the muscles responsible for the production of the biotremors. Mixed-effect linear regression models described the mechanism, and a model selection framework determined which model fit the data best. I then used an analysis of variance to partition the variance to each variable to determine which muscles were most important in the biotremor producing mechanism. The Mm. sternohyoideus superficialis et profundus, Mm. mandibulohyoideus, and M. levator scapulae were active during the production of biotremors. Mean latency calculations revealed that the M. levator scapulae and Mm. mandibulohyoideus activated prior to the vibration onset, and the Mm. sternohyoideus superficialis et profundus activated after the vibration onset. The M. sternohyoideus superficialis then ceased activity prior to vibration cessation, and the M. sternohyoideus profundus, Mm. mandibulohyoideus, and M. levator scapulae ceased activity after the vibration had ended. The description of the biotremor producing mechanism further supports that C. calyptratus can produce biotremors, possibly for communication.

Description et analyse de phénomènes enregistrés grâce à un ensemble capteur oscillographe enregistreur magnétique au cours des rencontres mâle-femelle chez quelques dyctinidae et agelenidae. La structure fine des phénomènes vibratoires engendres par les comportements et leur organisation temporelle ont été étudiés chez plusieurs espèces ce qui a permis une analyse comparative des éléments de communication intervenant lors du rapprochement des sexes

Historical and contemporary views such as those held within Buddhist and Hindu religion support the idea that sound, colour and form in motion have the ability to alter physiological and psychological aspects of human function. Within these, religions, distinctive singing and meditation techniques can be used to aid concentration, calm and balance the mind, and soothe the body. A meditative technique adopted by Hindu and Buddhist practitioners is to draw the mind into a centred point of focus, blocking out external distractions that inhibit concentration. The sound based meditation Om, for example, is a most powerful mantra, capable of healing and elevating consciousness (Beck, 1995). Vocal sounding and chant as well as gazing at or visualising images are techniques that have been utilised in ancient religious practice to aid people to develop their natural capabilities to shift energy within body and mind. Contemporary neuroscientists are interested in the states of mind that Buddhist monks claim to enter into while sounding. Equipped with technology for analysing brainwave activity, experiments have revealed that electromagnetic stimuli such as sound, light and colour can have physical affect upon the practitioner’s brain. Researchers have developed new therapeutic tools and techniques to benefit the health and well-being of individuals from these findings. This thesis traces the therapeutic use of sound, light, colour and form in motion from ancient Hindu and Buddhist religion into its use in complementary therapy. Sound Vision is the name of the film which fulfils the practical component of this research. Inspired by the visual form and motion of sound, this thesis contemplates: if we could see sound, what would it look like and could those images function as a healing art form? Sound Vision translates ancient and contemporary techniques of therapy into a digital audio/visual medium to function as visual therapy and aid for meditation. The themes of this research are foremost to visualise sound and secondly to deduce aspects of sound and vision that have therapeutic qualities. Chapter Three of this thesis thematically outlines qualities of sound that have been found to be capable of exciting or calming its listener. The same process has been applied for vision, specifically how light and colour affect the viewer as well as for form in motion. An interim presentation of the preliminary film, Dance of Light, was exhibited in November 2008 and here formative feedback was gained through unobtrusive observation and discussions with viewers toward the development of Sound Vision. Aspects of the film were found to provoke feelings of unease and tension while other aspects incited focus and calm. Sound Vision, serves as a prototype apply healing using light therapy to create positive physical and psychological outcomes. From the research presented within this thesis, Sound Vision employs various digital methods and techniques which are recognised with ability towards healing. Explorations to further this thesis’ research may include Neurological brainwave analysis and patient testing to determine which kinds of video footage produce particular desirable results.

Les interactions interindividuelles permettent la transmission de l’information, la dispersion des pathogènes et la mise en place des comportements dans une population. Cette thèse a permis d’évaluer l’influence des interactions sociales sur le succès de fondation colonial des différents reproducteurs de deux termites européens, l’invasif Reticulitermes flavipes et le natif R. grassei. Les résultats révèlent (i) un meilleur succès de fondation des reproducteurs primaires de R. flavipes, (ii) une organisation biparentale des soins aux jeunes toutes espèces confondues et (iii) une communication et des soins aux oeufs propres aux caractères invasif et natif des espèces d’étude. Pour finir, (iv) une meilleure survie et communication a été observée dans les colonies fondées avec reproducteurs secondaires tandis (v) qu’une communication supérieure et une survie moindre sont observées pour R. flavipes. Les origines évolutives de l’organisation biparentale et des variations de succès de fondations sont discutées
Individual interactions permit information transmission, pathogen dispersion and shape behavioral strategies in a population. This thesis has permit to explore the influence of social interactions on the colonial foundation success of two European termites, the invasive Reticulitermes flavipes and the native R. grassei. The overall results revealed (i) a better foundation success of primary reproductives of R. flavipes, (ii) a biparental organisation of parental care in both species (iii) a level of communication and egg care reflecting native and invasive status of the two species studied. To finish, (iv) better survival and communication rates were observed in colonies founded with secondary reproductives than in colonies without any and (v) a better communication rate and a weaker survival rate for R. flavipes foundations with or without secondary reproductives. Evolutive origins of biparental care and of the variations of foundation success observed are discussed

This PhD. thesis focuses on the vibrational communication of subterranean mammals, in particular, vocal communication of bathyergids (Heliophobius argenteocinereus, Fukomys mechowii, Fukomys darlingi) and seismic communication of Tachyoryctes. We recorded and analyzed the vocalization of three species and discussed the physical parameters of their vocalization in relationship to the special underground acoustic environment. Moreover, social systems of African mole-rats range from solitary to eusocial and thus our results enabled us to discuss the influence of sociality on vocal repertoire richness and its composition. Long distance communication possesses many challenges in underground environments; the only effective mean is seismic communication. We described for the first time seismic signaling in Tachyoryctes and proposed its function.

Vibrations are extremely widespread and ancient among animals’ communication modalities; nevertheless, their importance has been neglected for many years. During my PhD I wanted to increase the knowledge about the role of vibrational signals in insects. Therefore, I conducted behavioral bioassays and laser vibrometer recordings to describe and decipher vibrations produced by four species belonging to two different orders. The role of vibrational signals in intraspecific communication varies widely among different groups of insects. For this reason I chose to study two model groups, Hemiptera and Hymenoptera. Hemiptera, in particular leafhoppers, rely almost exclusively on vibrations for intraspecific communication. Their reproductive strategy is based on the production of vibrational calling and courtship signals, which are necessary for identification and location of the mating partner. Similarly, male-male competition for mating is regulated by means of specific vibrational signals, which in many cases are used to interfere with an ongoing mating duet. The emission of specific disruptive noise gives the rival male a chance to access mating by replacing the calling male in the duet. Recent studies showed that disruptive signals can be played back into plants to effectively disrupt the mating behavior of the grapevine leafhopper, Scaphoideus titanus. These findings inspired my research, its aims and the experimental approach. First, I described and decoded the reproductive strategy and associated vibrational signals of two grapevine leafhoppers species, the green leafhopper, Empoasca vitis and the glassy-winged sharpshooter, Homalodisca vitripennis. Secondly, I used the acquired knowledge to select potential synthetic ‘disruptive signals’ and test their efficacy in disrupting the mating process of E. vitis in laboratory conditions. Hymenoptera, on the other hand, such as paper wasps of the genus Polistes, use mainly semiochemicals to coordinate colony activities (e. g., to discriminate among individuals and their roles). However, the “mechanical switch hypothesis” suggested that vibrations produced by body oscillation movements of foundresses can bias larvae development towards a worker phenotype. That is, when a larva is subjected to low frequency vibrations it will develop into a worker. The social parasite - host system, Polistes sulcifer – P. dominula, was a very good model to investigate the potential caste determination function of body oscillation movements in paper wasps. P. sulcifer, the parasite, does not have a worker caste and its reproductive success rely exclusively on the brood cares provided by the host workers that emerge from usurped colonies. For this reason, I described and compared the vibrations transmitted to the nest by both species in usurped and not-usurped colonies. Moreover, the “mechanical switch hypothesis” predicts that vibrations manipulate larval development by modulating the “nutritional effect” (i.e. larvae that are fed more should develop into reproductive individuals and viceversa). Therefore, I tested the P. dominula foundress ability to modulate the vibration emission in association or not with the feeding activity. This research unveiled remarkable information in both model groups. Several original aspects in the leafhopper mating behavior have been discovered. Main peculiarities have been found in the daily activity and the potential role of visual stimuli in E. vitis, and in the complex structure of signals and male-male rivalry interactions in H. vitripennis. These results showed that multimodal communication (i.e. vision plus vibrations) and ecological adaptations still need to be studied in leafhoppers to fully understand how vibrational signals evolved and adapted to ecological constraints. From an applied point of view, we identified one disruptive signal that, in laboratory conditions, was highly effective in disrupting E. vitis mating process. On the other hand, I described, for the first time in detail, the spectral properties of induced vibrations into a paper wasps nest produced by P. dominula and its social parasite P. sulcifer. By comparing the vibrations produced by P. dominula, in different larval nutritional conditions, and the parasite we found several significant differences. For example, the foundress varies the spectral and temporal properties when she is feeding the larvae; while the parasite produces vibrational events with some exaggerated features compared to the host (i.e. each event is composed of a higher number of pulses). Results have been discussed from an adaptive point of view considering the putative role of vibrations in leading larvae caste determination. Overall, this thesis provides novel insights on the great variability of functions and adaptations of vibrational signals. The acquired knowledge can be used as a basis to perform further experiments on biological and applied aspects of biotremology.

Vibrations are extremely widespread and ancient among animals’ communication modalities; nevertheless, their importance has been neglected for many years. During my PhD I wanted to increase the knowledge about the role of vibrational signals in insects. Therefore, I conducted behavioral bioassays and laser vibrometer recordings to describe and decipher vibrations produced by four species belonging to two different orders. The role of vibrational signals in intraspecific communication varies widely among different groups of insects. For this reason I chose to study two model groups, Hemiptera and Hymenoptera. Hemiptera, in particular leafhoppers, rely almost exclusively on vibrations for intraspecific communication. Their reproductive strategy is based on the production of vibrational calling and courtship signals, which are necessary for identification and location of the mating partner. Similarly, male-male competition for mating is regulated by means of specific vibrational signals, which in many cases are used to interfere with an ongoing mating duet. The emission of specific disruptive noise gives the rival male a chance to access mating by replacing the calling male in the duet. Recent studies showed that disruptive signals can be played back into plants to effectively disrupt the mating behavior of the grapevine leafhopper, Scaphoideus titanus. These findings inspired my research, its aims and the experimental approach. First, I described and decoded the reproductive strategy and associated vibrational signals of two grapevine leafhoppers species, the green leafhopper, Empoasca vitis and the glassy-winged sharpshooter, Homalodisca vitripennis. Secondly, I used the acquired knowledge to select potential synthetic ‘disruptive signals’ and test their efficacy in disrupting the mating process of E. vitis in laboratory conditions. Hymenoptera, on the other hand, such as paper wasps of the genus Polistes, use mainly semiochemicals to coordinate colony activities (e. g., to discriminate among individuals and their roles). However, the “mechanical switch hypothesis” suggested that vibrations produced by body oscillation movements of foundresses can bias larvae development towards a worker phenotype. That is, when a larva is subjected to low frequency vibrations it will develop into a worker. The social parasite - host system, Polistes sulcifer – P. dominula, was a very good model to investigate the potential caste determination function of body oscillation movements in paper wasps. P. sulcifer, the parasite, does not have a worker caste and its reproductive success rely exclusively on the brood cares provided by the host workers that emerge from usurped colonies. For this reason, I described and compared the vibrations transmitted to the nest by both species in usurped and not-usurped colonies. Moreover, the “mechanical switch hypothesis” predicts that vibrations manipulate larval development by modulating the “nutritional effect” (i.e. larvae that are fed more should develop into reproductive individuals and viceversa). Therefore, I tested the P. dominula foundress ability to modulate the vibration emission in association or not with the feeding activity. This research unveiled remarkable information in both model groups. Several original aspects in the leafhopper mating behavior have been discovered. Main peculiarities have been found in the daily activity and the potential role of visual stimuli in E. vitis, and in the complex structure of signals and male-male rivalry interactions in H. vitripennis. These results showed that multimodal communication (i.e. vision plus vibrations) and ecological adaptations still need to be studied in leafhoppers to fully understand how vibrational signals evolved and adapted to ecological constraints. From an applied point of view, we identified one disruptive signal that, in laboratory conditions, was highly effective in disrupting E. vitis mating process. On the other hand, I described, for the first time in detail, the spectral properties of induced vibrations into a paper wasps nest produced by P. dominula and its social parasite P. sulcifer. By comparing the vibrations produced by P. dominula, in different larval nutritional conditions, and the parasite we found several significant differences. For example, the foundress varies the spectral and temporal properties when she is feeding the larvae; while the parasite produces vibrational events with some exaggerated features compared to the host (i.e. each event is composed of a higher number of pulses). Results have been discussed from an adaptive point of view considering the putative role of vibrations in leading larvae caste determination. Overall, this thesis provides novel insights on the great variability of functions and adaptations of vibrational signals. The acquired knowledge can be used as a basis to perform further experiments on biological and applied aspects of biotremology.

Social life requires a complex and efficient communication system. Traditionally, chemical communication is considered the most important sensory channel in insects societies. However, in the last decades, visual and substrate-borne vibrational communication have inspired a growing interest. In order to understand if these understudied sensory channels could be used in fundamental aspects of social life, such as nestmate recognition, dominance hierarchies and adult-brood interactions, I used the primitively eusocial paper wasp Polistes dominula, whose features of nest structure and the body coloration pattern are suitable to vibrational and visual communication. The main results of this work are: i) P. dominula wasps can use both visual and chemical signals in nestmate recognition according to the colony social environment; ii) substrate-borne vibrations produced by adult females evoke a measurable behavioral response in larvae, which thus provides evidence that vibrations can play a role as signal; iii) the intensity of vibrations produced by different females in associative foundations is related to individual position in the dominance hierarchy position and, from the physiological point of view, to ovary development, suggesting that such feature could vehicle individual information; iv) finally, the study of vibrations produced by Polistes sulcifer, the obligate social parasite of P. dominula, suggests that the parasite could exploit the vibrational host communication system to get integrated into the host colony. Overall, the results of this work show that communication modalities other than the chemical one can play a crucial role in regulating insect social life.

With the rise of the Internet of Things, more and more devices are being connected to the internet, driving up the demand for wireless connectivity. In addition to advancing the current RF technology, optical communication, specifically IR wireless communication, is a competitive option to help offload some of the wireless demand. However, one of the crucial components for an effective IR system is the ability to quickly and controllably steer the IR light around a room, providing data as a device moves. This thesis focuses on tip-tilt MEMS micromirrors for indoor optical wireless communication (OWC), specifically two key aspects, (1) design and (2) controls. We discuss two unique tip-tilt mirror designs for indoor OWC. The first is an electrothermal varifocal mirror capable of changing its shape, and therefore the shape of the beam in real time. The mirror's radius of curvature can range between -0.48 mm and 20.5 mm, focusing light from a bare fiber from a half-angle divergence of 5° to 0.18° The second mirror uses electromagnetic actuation to achieve a large quasi-static angular range capable of ±60° mechanical ±120° optical) about two rotation axes. In other words, with a laser beam focused on the mirror from the zenith, the device could direct the beam anywhere in a hemisphere. In addition to the device design, we discuss a series of control techniques that can improve the step-and-settle response time of a MEMS device by orders of magnitude compared to a traditional step input. For example, this technique is used to settle the above magnet mirror within 4.5 ms, a factor of 300 improvement over the 1.35 s settling time of a traditional step input. These techniques can be used in conjunction with pulse width modulation (PWM) to provide a fast, low-cost controls solution with no loss in performance. Designing mirrors with these types of controls in mind will not only benefit OWC but enable new applications as well.

Large structures exposed to the environment such as the collinear omni and large panel communication antennas in this research suffer damage from cyclic wind, rain, hail, ice load and impacts from birds and stones. Stresses from self-weight, ice loading and wind gusts will produce deformations of the structure that will lead to performance deterioration of the antenna. In order to avoid such a case, it is important to understand the static, dynamic and aerodynamic behavior of these structures and thus optimization can be achieved. In this research the current fluid-structure interaction methods are used to model, simulate and analyze these communication antennas in order to assess whether failure would occur under service loads. The FEA models developed are verified against analytical models and/or experiments. Different antenna configurations are compared based on their capacity to minimize vibration effects, stress-induced deformations and aerodynamic loading effects.

This thesis details the creation of a novel acoustic device, one which requires no power and is activated by the frequency of an acoustic wave. This device, named an acoustic switch in this paper, lays dormant until a continuous wave acoustic signal excites it at its specific design frequency, at which point it outputs a voltage. There currently are devices, namely hydrophones, that yield similar results, but are not activated by a specific frequency. The acoustic switch can be used in applications that require acoustic communications where power usage is critical, such as in battery powered unmanned underwater vehicles. The acoustic switch operates based on the principles of resonance induced by acoustic signals. Resonance creates large displacement harmonic motion in a mass spring system and this displacement can be converted to electrical signals. This thesis lays out the mechanical design of three different types of acoustic switches, each acting on different modes of resonance. The designs are analyzed numerically and through finite element analyses to determine the resonance frequency of each as a function of size, and the sensitivity of each design. A proof of concept prototype is constructed and successfully tested in the acoustic laboratory at Boston University to prove that an acoustic switch can work. The analyses show that designs can be created in the diameter range of 5 cm to 200 cm with actuation frequencies from 2,000 Hz to 50,000 Hz, where the size is inversely proportional to the actuation frequency. The designs can have sensitivities up to 15,000 Volts per Pascal of peak pressure amplitude. The voltage output from the switch can either be used as is or be fed to an ultra low power signal conditioning unit. The signal conditioning units use energy efficient active electronics and have a battery life of up to 46 years. The acoustic switch can usher in the development of a new category of low power sensors that can be used in commercial, military, and consumer applications.