Shoplifting is a serious issue that causes loss to retail owners. However, the loss can be avoided by adding preventative measures to deter shoplifters from committing the crime. Surveillance [2] and a store's design and layout [3] are considered significant factors that could deter them. Considering that background music is a part of a store's design, this research combined surveillance and a store's design to discourage shoplifters by creating changes to the background music that could make the shoplifters feel observed. Ultimately, this research asked these questions: 1) If a change in background music could make the visitor feel observed, what are the possible design strategies? and 2) which design is preferable? In this research, eight participants watched a first-person view of a shopper going around the shop and lifting a clothing article. The participants were asked to create a sound alert that matched the lifting action, mixed with three different background music tracks. Afterwards, they were asked to hand in the documentation of their design. Apart from that, they were asked to fill in a quantitative survey evaluating all the designs (including other participants' designs) and describe the design with three keywords. This research discovered that there were three main approaches in designing the sound alert, and there were certain preferences of a design approach dependent on the type of background music. In other words, there is a correlation between the type of background music and the preferred design approach. This work also discussed its limitations and presented opportunities for future research. / Snatteri är ett allvarligt problem som orsakar förluster för butiksägare. Förlusterna kan dock undvikas genom förebyggande åtgärder för att avskräcka butikstjuvarna från att begå brottet. Övervakning [2] samt butikens design och planlösning [3] anses vara viktiga faktorer som kan avskräcka dem. Med tanke på att bakgrundsmusik är en del av en butikens design kombinerar denna forskning övervakning och butikens design för att avskräcka snattare genom att skapa förändringar i bakgrundsmusiken som kan få snattarna att känna sig observerade. Avslutningsvis ställde den här forskningen dessa frågor: 1) Om en förändring av bakgrundsmusiken kan få besökaren att känna sig observerad, vilka är då de möjliga designstrategierna? och 2) Vilken design är att föredra? I den här forskningen tittade åtta deltagare på en shoppare från hen som går runt i butiken och lyfter ett klädesplagg. Deltagarna ombads att skapa ett ljudlarm som matchade lyfthandlingen, blandat med tre olika bakgrundsmusikspår. Efteråt ombads de att lämna in dokumentationen av sin design. Dessutom ombads de att fylla i en kvantitativ enkät där de utvärderade alla konstruktioner (inklusive andra deltagares konstruktioner) och beskrev konstruktionen med tre nyckelord. Forskningen visade att det fanns tre huvudsakliga tillvägagångssätt vid utformningen av ljudvarningen, och att det fanns vissa preferenser för ett tillvägagångssätt beroende på typen av bakgrundsmusik. Med andra ord finns det en korrelation mellan typen av bakgrundsmusik och den föredragna designmetoden. I detta arbete diskuterades också dess begränsningar och presenterades möjligheter för framtida forskning.

Corrugated pipes are widely used in offshore gas and oil fields for their flexibility while offering local rigidity. However, self-sustained pressure pulsations associated with the flow in corrugated pipes results in a noisy environment, high running costs and eventually structure fatigue failure upon long exposure. Recent literature has addressed either the flow over a single cavity or the global oscillations. The current research aims at understanding the flow over multiple cavities as a first step to correlate the rich single cavity literature and the actual corrugated pipe problem with the ultimate goal of predicting oscillations amplitude in corrugate pipes. The standing wave method (SWM), which is an efficient experimental tool, has been successfully adapted in the first phase of the project to measure the source of multiple cavity configurations. One, two and three-cavity configurations have been investigated by means of the SWM. The source non-linearly becomes more pronounced as the number of cavities increases. The cavity length (L) is still found to be the appropriate length scale to define the oscillation dimensionless frequency (the Strouhal number). The measured source data have been successfully employed in a semi-empirical model to predict the amplitude of the self-excited oscillations. Accurate model performance is achieved for the single, double and triple cavity configurations. Including the absorption losses at the cavity corners has been found to be crucial for the model prediction accuracy. The separation distance (Lp) effect on the generated source is investigated for two and three-cavity configurations using the SWM over a practical range of spacing ratios. At extremum spacing ratios of (Lp/L) 0.5 and 1.375, constructive hydrodynamic interference associated with strong sources has been observed. At high excitation levels the source consistently becomes weaker upon increasing the spacing ratio. The reported trends are consistent for both the double and triple cavity configurations. However, the destructive interference spacing ratio is found to depend on the number of cavities indicating a relatively more complicated interaction mechanism. The different interaction patterns have been analytically interpreted based on the synchronization of the hydrodynamic cycle of the cavity shear layer and the disturbance convection along the pipe spacing between the cavities. Moreover, the three-cavity constructive interference cases have been visualized using Particle Image Velocimetry (PIV). The source evaluated based on the PIV data and applying Howe’s analogy revealed each cavity share of the global source, which fairly agrees with the SWM measured source. The source contribution due to gradually increasing the number of cavities is investigated using the SWM up to a six-cavity configuration. The source contribution reaches asymptotically a consistent value starting from the fourth cavity. This persistent contribution defines a building unit cavity source which is representative of a general cavity in a long corrugated pipe. The building unit source fairly agrees with the ninth-cavity source in a twelve-cavity configuration extracted by means of the PIV technique. Finally, a predication model, based on the building unit source, successfully predicts the oscillations amplitude of a twelve-cavity configuration, which serves as a model for a corrugated pipe section. / Thesis / Doctor of Philosophy (PhD)

Due to its sensitive nature, the graveyard is often an avoided problem space within the field of design. This becomes evident from the lack of exploration and analysis in this domain. Anyhow, it represents an opportunity to test how design can mediate between sacred places, technology and people. Moreover, as a very specific context, the graveyard encompasses peculiar ways of interacting and experiencing space that deserve to be taken into account. This work discusses the notions of space and place and how the field of interaction design can benefit from them. In doing so, it investigates the hidden dimensions of the graveyard that make it a complex structure where spatial, personal and socio-cultural dimensions are intertwined. While the fieldwork aims at analysing the graveyard in its different tones of meaning (identity, memorial, cultural differences, on-site interaction) the focus of the work are the practices of memory and the role that the past has in our relation with the deceased. The result of the design process is an interactive audio system composed of a playback circuit based on Arduino and boxed into a seashell. The device is designed to be placed on the grave and store audio content. Once activated, the audio seashell allows listening and eventually recording vocal traces related to the deceased’s past. Taking into account the observed practices, rules and conventions that shape the graveyard, the role of personal and collective rituals and the meanings of all the identified artifacts, the designed system supports the experience of recalling memories in respect to the atmosphere, tempo and rhythm that characterise the graveyard.

The growth that aviation has seen in the last decades has drawn the attention on the environmental impact of aircraft. An important part of this environmental impact is the noise emitted by air vehicles, which is considered rather significant for community annoyance. The generation and propagation of air vehicle noise are two different areas of interest, which require accurate prediction in order to control the emitted noise levels. The present thesis employs numerical methods in order to investigate various air vehicle noise propagation effects. It is divided in two parts: the far field and the near field study. Each of these studies is concentrated on the sound propagation mechanisms that are dominant for each case and uses a numerical method that is best suited for it in terms of mechanisms incorporated and cost effectiveness. The far-field study of this thesis focuses on the nonlinear propagation of helicopter rotor noise using the Burgers equation, a well known one direction propagation method. The Burgers equation incorporates geometrical spreading, atmospheric absorption and nonlinear distortion effects. Towards this study, the HELISHAPE descent case experimental database is used. Blade Vortex Interaction (BVI) noise, the dominant noise contributor during descent, is mainly examined. It is shown that advancing side BVI noise is affected by nonlinear distortion, while retreating side BVI noise is not. For some frequency bands the difference between linear and nonlinear calculations can be as high as 7 dB. Based on signal characteristics at source, two quantities are derived. The first quantity (termed polarity) is based on the pressure gradient of the source signal and can be used to determine whether a BVI signal will evolve as an advancing or a retreating side signal. The second quantity (termed weighted rise time) is a measure of the impulsiveness of the BVI signal and can be used to determine at which frequency nonlinear effects start to appear. Finally, polarity and weighted rise time are shown to be applicable in cases of BVI noise generated from different blade tips, as well as, in cases of non-BVI noise. However, employment of the Burgers equation can be time consuming to be included in routine calculations. It also requires knowledge of the initial pressure time signal. The power spectrum alone, which is usually known, is not sufficient. In order to overcome these difficulties, three prediction methods are presented that are based on the Burgers equation. These are: i) a numerically generated database, ii) correlation equations and iii) the phase assignment method. Near field propagation of air vehicle noise requires different treatment than far field. The effects which are mainly affecting the propagation are geometrical spreading, convection and refraction effects due to the flow field, as well as reflections and diffraction on the air vehicle surfaces. Towards these objectives, a new low-order flow/acoustics interaction method for the prediction of sound propagation and diffraction in unsteady compressible flow using adaptive 3-D hybrid grids is investigated. The total field is decomposed into the flow field described by the Euler equations, and the acoustics field described by the Nonlinear Perturbation equations. The method is shown capable of predicting monopole sound propagation, while employment of acoustics-guided adapted grid refinement improves the accuracy of capturing the acoustic field. Interaction of sound with solid boundaries is also examined in terms of reflection and diffraction. Sound propagation through an unsteady flow field is examined using static and dynamic flow/acoustics coupling demonstrating the importance of the latter. Proof of concept for the new method is provided by its application to the case of a conventional jet transport airplane, examining the effect of flow field and wing shielding on the near field noise levels. During the aforementioned noise investigation and analysis, results on Blade Wake Interaction (BWI) noise were also reached. Presently, the mechanism of BWI noise generation, as well as the corresponding prediction model, are still under consideration. Helicopter rotor BWI noise is known to be significant during take-off and level flight, while less attention has been given to descent flight conditions, where BVI noise is dominant. Through signal analysis of the HELISHAPE descent case acoustic database, the rotor azimuthal region responsible for BWI noise is localized and the dominance of BVI noise in the BWI frequency region is shown. Coherence analysis of the blade pressure data indicate significant chordwise coherence in the 3 to 4 Struhal number range and absence of acoustic dipoles in the BWI frequency range. The findings of this study support BWI prediction models based on Amiet’s theory and suggest that BWI noise can be ignored for predictions of rotor noise in descent flight conditions. / Η ανάπτυξη που συναντάται στην αεροπλοΐα τις τελευταίες δεκαετίες έχει τραβήξει την προσοχή στην περιβαλλοντολογική επίδραση των αεροσκαφών. Ένα σημαντικό μέρος αυτής της επίδρασης είναι ο θόρυβος των αεροχημάτων ο οποίος ευθύνεται κατά ένα μεγάλος μέρος για την ενόχληση του πληθυσμού στις περιοχές των αεροδρομίων και όχι μόνο. Η δημιουργία και η διάδοση του θορύβου αεροχημάτων είναι δύο διαφορετικές περιοχές ενδιαφέροντος, οι οποίες απαιτούν ακριβή πρόβλεψη στην προσπάθεια ελέγχου των εκπεμπόμενων ηχητικών επιπέδων. Η παρούσα διατριβή χρησιμοποιεί αριθμητικές μεθόδους για τη μελέτη της διάδοσης του θορύβου αεροχημάτων. Χωρίζεται δε σε δύο μέρη: τη μελέτη του μακρινού και του κοντινού πεδίου. Καθεμία από αυτές τις μελέτες επικεντρώνεται στους μηχανισμούς ηχητικής διάδοσης που είναι κυρίαρχοι σε κάθε περίπτωση και χρησιμοποιεί μια αριθμητική μέθοδο που ταιριάζει καλύτερα όσο αναφορά την απόδοσή της και τους μηχανισμούς που εξετάζονται. Η μελέτη μακρινού πεδίου εστιάζεται στη μη-γραμμική διάδοση θορύβου ρότορα ελικοπτέρου με τη χρήση της εξίσωσης Burgers, μιας γνωστής μεθόδου υπολογιστικής διάδοσης ήχου σε μία διεύθυνση. Η εξίσωση Burgers περικλείει τα φαινόμενα της γεωμετρικής εξασθένισης, ατμοσφαιρικής απορρόφησης και μι-γραμμικής στρέβλωσης. Σε αυτή τη μελέτη χρησιμοποιήθηκαν τα δεδομένα του πειράματος HELISHAPE. Ο θόρυβος από αλληλεπίδραση πτερυγίου-στροβίλου (BVI noise), ο οποίος είναι ο κυρίαρχος αεροδυναμικός θόρυβος στην περίπτωση της καθοδικής πτήσης, είναι αυτός που εξετάστηκε κυρίως. Αποδείχθηκε ότι ο θόρυβος BVI στην πλευρά του προχωρούντος πτερυγίου (advancing side) επηρεάζεται σημαντικά από τα μη-γραμμικά φαινόμενα σε αντίθεση με την πλευρά του υποχωρούντος πτερυγίου (retreating side). Μερικές μπάντες συχνοτήτων έδειξαν διαφορές μεταξύ γραμμικής και μη-γραμμικής διάδοσης έως και 7dB. Βασιζόμενοι στα χαρακτηριστικά των σημάτων, δύο νέα μεγέθη ορίστηκαν. Το πρώτο από αυτά, με το όνομα πολικότητα (polarity) βασίζεται στην παράγωγο της ακουστικής πίεσης του αρχικού σήματος και μπορεί να προσδιορίσει αν το σήμα θα διαδοθεί σαν προχωρούν ή υποχωρούν. Το δεύτερο μέγεθος, με το όνομα ζυγισμένος χρόνος ανόδου (weighted rise time) είναι μια εκτίμηση της παλμικότητας του σήματος BVI και μπορεί να χρησιμοποιηθεί για να προσδιορίσει την περιοχή συχνοτήτων όπου τα μη-γραμμικά φαινόμενα θα ξεκινήσουν να εμφανίζονται. Αυτά τα μεγέθη αποδείχθηκε ότι μπορούν να χρησιμοποιηθούν και σε περιπτώσεις θορύβου BVI άλλων πτερύγων, καθώς και σε μη-BVI σήματα. Ωστόσο, η χρήση της εξίσωσης Burgers μπορεί να είναι χρονοβόρα αν συμπεριληφθεί σε υπολογισμούς ρουτίνας. Ακόμη προϋποθέτει γνώση του αρχικού σήματος ακουστικής πίεσης. Το ηχητικό φάσμα από μόνο του, που συνήθως είναι γνωστό, δεν είναι αρκετό. Για να ξεπεραστούν αυτές οι δυσκολίες, παρουσιάζονται τρεις μέθοδοι πρόβλεψης οι οποίες βασίζονται στην εξίσωση Burgers. Αυτές είναι: i) μια υπολογιστικά δημιουργημένη βάση δεδομένων ii) εξισώσεις συσχετίσεων και iii) η μέθοδος της ανάθεσης φάσης. Η μελέτη διάδοσης θορύβου στο κοντινό πεδίο απαιτεί διαφορετική μεταχείριση από το μακρινό πεδίο. Τα φαινόμενα που την επηρεάζουν περισσότερο είναι αυτά της γεωμετρικής εξασθένισης, μεταφοράς και περίθλασης λόγω του ροϊκού πεδίου, καθώς και ανάκλαση και διάθλαση στις επιφάνειες του αεροχήματος. Για το λόγο αυτό μελετάται μια νέα μέθοδος χαμηλής τάξης ακρίβειας, αλληλεπίδρασης ροϊκού-ακουστικού πεδίου για την διάδοση και διάθλαση ήχου σε ασταθή συμπιεστή ροή με τη χρήση 3D υβριδικού πλέγματος. Το ολικό πεδίο διαχωρίζεται στο ροϊκό πεδίο περιγραφόμενο από τις εξισώσεις Euler και το ακουστικό πεδίο από τις μη-γραμμικές εξισώσεις διαταραχών. Η μέθοδος αποδεικνύεται ικανή να προβλέψει την ηχητική διάδοση μονοπόλου, ενώ η χρήση προσαρμοσμένου πλέγματος βελτιώνει την ακρίβεια του ηχητικού πεδίου. Η αλληλεπίδραση ήχου και στερεών επιφανειών εξετάζεται επίσης σχετικά με τα φαινόμενα ανάκλασης και διάθλασης. Εξετάζεται ακόμα η διάδοση ήχου σε ασταθές ροϊκό πεδίο χρησιμοποιώντας στατική και δυναμική σύζευξη και αποδεικνύεται η σημαντικότητα της δεύτερης. Απόδειξη χρηστικότητας της νέα μεθόδου επιδεικνύεται με την εφαρμογή για την περίπτωση συμβατικού επιβατηγού αεροσκάφους, όπου εξετάζονται τα φαινόμενα της επίδρασης της ροής και της ηχητικής κάλυψης της πτέρυγας στα ηχητικά επίπεδα του κοντινού πεδίου. Κατά τη διάρκεια των παραπάνω ακουστικών διερευνήσεων, επιτεύχθηκαν ακόμα κάποια αποτελέσματα πάνω στον θόρυβο λόγω αλληλεπίδρασης πτερυγίου-απορεύματος (BWI noise). Μέχρι τώρα ο ακριβής μηχανισμός του θορύβου BWI, όπως και το αντίστοιχο μοντέλο πρόβλεψης, αποτελεί θέμα μελετών. Ο θόρυβος BWI στα ελικόπτερα είναι γνωστό ότι είναι σημαντικός στις περιπτώσεις ανοδικής και επίπεδης πτήσης, ενώ μικρή βαρύτητα έχει δοθεί στην περίπτωση της καθοδικής πτήσης λόγω της κυριαρχίας του BVI θορύβου. Μέσω ανάλυσης σημάτων του HELISHAPE για τη περίπτωση της καθοδικής πτήσης, εντοπίστηκε η περιοχή του δίσκου του ρότορα υπεύθυνη για τον θόρυβο BWI και δείχθηκε η επίδραση του θορύβου BVI στην περιοχή συχνοτήτων BWI. Ανάλυση συνοχής (coherence analysis) των αεροδυναμικών πιέσεων των πτερυγίων έδειξε σημαντικές τιμές στη περιοχή τιμών 3 με 4 αριθμών Struhal και απουσία ακουστικών διπόλων στην περιοχή συχνοτήτων του BWI. Τα ευρήματα της παρούσας μελέτης υποστηρίζουν το μοντέλο πρόβλεψης θορύβου BWI που βασίζεται στη θεωρία του Amiet και προτείνουν ότι ο θόρυβος BWI μπορεί να αγνοηθεί στις προβλέψεις θορύβου ρότορα σε συνθήκες καθοδικής πτήσης.

Sur la base d’une pratique artistique explorant le phénomène vibratoire de la matière, cette thèse propose une réflexion sur les interactions entre matières sonores et matières visuelles au sein d’une même production plastique. Il s’agit d’analyser l’acte de création composé d’un agencement sensible de divers éléments auditifs et visuels réagissant de manière réciproque et provoquant une mutation de leur perception sensorielle, émotionnelle et sémantique. Un tour d’horizon de certains grands acteurs de l’histoire des pratiques sonores au XX° et XXI° siècle permettra d’aborder la question de l’interaction entre l’ouïe et la vue dans une production artistique. Seront abordées les notions de plasticité sonore, de mouvement vibratoire par l’altération, ainsi que du métissage plastique issu du métissage culturel. Dans un second temps, mon étude portera sur le processus de création d’une installation sonore par mode vibratoire, à travers l’écoute, le processus d’écriture sonore et les caractéristiques des espaces publics en tant que lieu d’accueil d’une œuvre. En dernier lieu, l’étude de la spécificité de la vibration sonore à générer des émotions, mettant en relief les mécanismes cérébraux sollicités par la perception bi-sensorielle aussi bien au niveau du corps de l’artiste créant, que ceux du public expérimentant l’œuvre. / On the basis of an artistic practice exploring the vibratory phenomenon of matter, this thesis proposes a reflection on the interactions between sound and visual materials within the same plastic production. It is a matter of analyzing the act of creation comprising a sensoriel arrangement of various auditory and ocular elements reacting reciprocally and causing a mutation of their sensory, emotional and semantic perception. A survey of some of the major 20th and 21st century players in the history of sonic cultural practices will address the issue of the interaction between hearing and sight in an artistic production. The notions of sound plasticity, of vibratory movement through alteration, as well as that of plastic mixing resulting from cultural intermingling will be discussed. secondly, my study will focus on the process of creating a sound installation by vibratory mode, through listening, the process of sound writing and the characteristics of public spaces as an artwork. Finally, the study of the specificity of sound vibration to generate emotions, highlighting the cerebral mechanisms required by bi-sensory perception both in the body of the creative artist and those of the public experiencing the 'artwork.

[pt] O presente estudo parte da premissa de que novas formas de se comunicar surgem ao longo dos anos, inclusive na relação entre o humano e a máquina, onde, atualmente, a fala é o veículo comunicacional predominante. E nesse diálogo há uma busca para a adequação da máquina à nossa forma de comunicação e uma constante necessidade de adequação dos seres humanos à forma de comunicação da máquina. Essa investigação visa elucidar se sistemas baseados em interfaces de voz compõe o modelo de interação fundado no que se define como conversa, sendo amparados pelas áreas da ergonomia e usabilidade e por fundamentos provenientes da teoria da conversação. Este trabalho encontra-se estruturado em quatro seções: a primeira equivale a fundamentação teórica; a segunda seção abrange o levantamento de dados através de entrevistas com usuários de interfaces conversacionais; a terceira seção constitui-se na análise de conteúdo das entrevistas; e por fim, a quarta seção envolve as considerações em torno das experiências no uso de interfaces conversacionais atuais. / [en] The present study starts from the premise that new ways of communication are emerging throughout the years, including the relationship between human and machine, which nowadays, speech is the predominant communicational vehicle. And in this dialogue, there is a search for the adaptation of the machine to our form of communication and a constant need to human s adaptation to the machine s form of communication. This investigation attempts to clarify if systems based on voice interfaces are in fact composed by a model of interaction that is defined as conversation, and if they are actually being supported by the areas of ergonomics, usability, and also by the basics fundaments of conversation theory. This work finds itself structured in four sections: the first one corresponds to the theoretical foundations; the second section embraces data collection, which gathered several interviews with the users of conversational interfaces; the third section is established on the content analysis of the previous interviews; lastly, the fourth section concerns the final considerations of the current experience of conversational interfaces.