Dissertations / Theses on the topic 'Audio cues'

Includes bibliographical references.<br>Today many airborne and terrestrial acquisitions capture point clouds of scenes or objects to be modelled. But before modelling can be done point clouds need to be taken through processing steps such as registration, cleaning, simpli_cation, etc. These point clouds are usually manually processed before being processed automatically. Manual processing of point clouds depends on the visual interaction the user has with the point cloud provided by the visual cues. This research investigated enhancing the level of interaction the user has with the point cloud when processing it. The proposed method augments audio in point clouds to enhance its processing where visual cues are limited. This investigated _nding objects/points of interest in the point cloud while processing it by estimating the position (azimuth and elevation) and depth of audio objects associated with these point cloud objects. The occupancy of space of audio objects was also investigated to determine the unseen events around objects of interest in the point cloud. For example, in a scan registration problem, audio could be augmented to a misaligned scan. As this scan is manually rotated and translated into alignment, various audio cues can be used to inform the user of the state of this alignment. An outlier separated from a surface in a point cloud could be identi_ed and removed by augmenting audio to a volumetric brush that does the point cloud cleaning. Associating audio cues of the audio object with the depth of the outlier to the surface could help the user identify this outlier. Similar implementation could be adopted in point cloud simpli_cation tasks. Various audio cues exist which allow a listener to discern particular information about a sound source. This is done by the human auditory system, using cues such as intensity, pitch, reverberation and HRTFs to discern this information. However, limitations exist in retrieving this information. Literature supports the use of the auditory interface in applications commonly built for the visual interface. The addition of the auditory interface is seen as a way of increasing the interaction users have with applications and therefore improving the experience. An auditory interface was built to help undertake this research. The test subject was immersed in the auditory environment by wearing headphones. This meant that the subject and the virtual listener were merged, allowing the subject to receive emitted audio. The perception of the audio was with respect to the virtual listener.

Mestrado em Engenharia de Computadores e Telemática<br>A oferta de dispositivos móveis para navegação e orientação tem aumentado ao longo dos últimos anos devido à revolução móvel, impulsionada pelo acesso generalizado a smartphones com GPS integrado e outras tecnologias semelhantes que fornecem informação geográfica, visando diferentes cenários de utilização tais como condução de veículos ou navegação pedestre. Porém, a forma como estes dispositivos interagem com o utilizador não e apropriada para indivíduos com dificuldades visuais nem para situações onde o utilizador não possa utilizar a visão para se orientar (e.g. equipas de primeiros socorros em missão de salvamento num local onde há fumo, nevoeiro ou noutras condições de visibilidade reduzida). Nos últimos anos, os sistemas de navegação audio têm sido apontados como uma possível solução para este problema. Nesta dissertação abordamos esta temática desenvolvendo um sistema - AudioNavigator - que fornece instruções via áudio. AudioNavigator é um sistema (aplicação) para dispositivos móveis Android capaz de converter sinais de áudio mono em sinais de audio espacial que são percebidos pelo utilizador como provenientes de uma determinada localização, orientando-o até à localização alvo. O objectivo principal do AudioNavigator é guiar um indivíduo equipado com um dispositivo móvel com GPS até um determinado local recorrendo apenas a instruções áudio. O sistema foi desenvolvido com base num modelo head-related transfer function (HRTF) que modula o tempo e intensidade das instruções áudio de forma a gerar uma percepção 3D do som para os utilizadores que envergam um par de auriculares. O AudioNavigator foi testado quanto à percepção espacial de 10 participantes que conseguiram identificar o ângulo correcto de determinado som em 63% das vezes, com uma margem de 30 graus. Além disso, o sistema foi testado em duas séries em campo aberto onde dois percursos, um composto por 12 e outro composto por 25 pontos geográficos, foram percorridos por 5 participantes, tendo estes apenas as orientações áudio do sistema como suporte. Os 5 participantes completaram os 10 caminhos com sucesso. Estes resultados demonstram o actual potencial dos dispositivos móveis para serem utilizados em cenários de navegação sem recurso a visão. O Audio-Navigator consiste numa prova de conceito para a utilização de sistemas de navegação áudio neste tipo de cenários.<br>Navigation and orientation assistive devices availability has been increasing over the years due to the "mobile revolution", propelled by the generalized accessibility to smartphone integrated GPS systems and other similar technologies that provide location information, targeting di erent usage scenarios such as car driving or pedestrian navigation. Nevertheless, the way these consumer devices interface with the users are not appropriate for visually impaired individuals nor to critical situations where users cannot rely on vision for navigation (e.g. rst responders involved in rescue procedures in dense smoke presence or other reduced visibility conditions). Over the past years, audio guidance systems have been pointed in the literature as a possible solution to this problem. In this thesis we address this topic by developing a system - AudioNavigator - that provides navigation via audio signatures. AudioNavigator is an Android mobile application that is able to convert monaural audio signals into spatial audio signals that are perceived by the user as coming from a certain direction, thus guiding him towards the target destination. The main objective of AudioNavigator is to guide an individual equipped with a GPS-enabled mobile device to a given destination through solely audio cues. The system was developed based on a "head-related transfer function" (HRTF) model that modulates time and intensity of audio pitch cues to generate 3D direction perceptions to users wearing a set of headphones. AudioNavigator was tested for angle perception with 10 volunteers that were able to select the correct angle based on the audio cues in 63% of the times within a 30 degrees margin. Furthermore, the system was tested in two open eld trials where two paths, composed of 12 and 25 waypoints, were tested by 5 users, solely relying on the audio guidance provided by the system. The 5 users completed all 10 paths with success. These results demonstrate the current potential of mobile devices to be used in non-visual navigation scenarios. AudioNavigator provides a proof of concept for the usage of audio navigation systems in such scenarios.

Objects that move in depth (looming) are ubiquitous in the real and virtual worlds. How humans interact and respond to these approaching objects may affect their continued survival in both the real and virtual words, and is dependent on the individual's capacity to accurately interpret depth and movement cues. In computer-generated environments, including hyper and virtual reality,film, and gaming, these cues are often complex sounds with multiple audio cues that are creatively designed for maximum effect. To accurately generate a dynamic and rich perception of looming objects, the design of such complex stimuli should be based on a firm scientific foundation that encompasses what we know about how people visually and aurally perceive events and interactions. Conversely, many psychological studies investigating auditory looming depict the object's movement using simple audio cues, such as an increase in the amplitude, which are applied to tones that are not regularly encountered in the natural world, such as sine, triangle, or square waves. Whilst the results from these studies have provided important information on human perception and responses, technological advances now allow us to present complex audiovisual stimuli and to collect measurements on human perception and responses to real and hyper-real stimuli. The research in this thesis begins to address the gap that exists between the research corpus and industry usage. This is initially accomplished by conducting a feature analysis of the audio cues and complex sounds constructed by sound designers for film scenes presenting objects moving in depth. This is followed by a perceptual study measuring human responses, both physical and emotional, to the complex audio cues designed for the film scenes. Using physical models, we then select a number of audio cues for closer inspection and introduce the parameter of `room reflections' as an audio cue. We investigate whether or not human responses to various audio cues differ when they are presented individually or in combination, or when they are applied to an artificial (square wave) sound source or a real world sound source. Finally, we test the capacity of these audio cues to bias multimodal auditory-visual perception of an approaching object.

Depuis une dizaine d’années, des techniques de codage joint, exploitant les relations et les redondances entre canaux audios, ont été développées afin de réduire davantage la quantité d’information nécessaire à la représentation des signaux multicanaux. Dans cette thèse, nous étudions plus particulièrement le codage des signaux audio stéréo en l’absence d’informations à priori sur la nature des sources en présences, leur nombre et la manière dont elles sont spatialisées. Cette situation correspond à l’immense majorité des enregistrements commerciaux dans l’industrie de la musique et du multimédia de manière générale. Nous étudions des approches paramétrique et signal de la problématique de codage de ces sources, où les deux sont souvent mêlées. Dans ce contexte, trois types d’approches sont utilisés. L’approche paramétrique spatiale consiste à réduire le nombre de canaux audio de la source à coder et à recréer le nombre de canaux d’origine à partir des canaux réduits et de paramètres spatiaux, extraits des canaux d’origine. L’approche signal conserve le nombre de canaux d’origine, mais encode des canaux construits à partir de ces derniers et présentant moins de redondances. Enfin, l’approche mixte introduite dans MPEG USAC utilise un signal audio et un signal résiduel, issu d’une prédiction, et dont les paramètres sont codés conjointement. Dans cette thèse, nous analysons tout d’abord les caractéristiques d’un signal stéréo issu d’un enregistrement commercial et les techniques de production associées. Cette étude nous mène à une réflexion sur les rapports entre les modèles paramétriques d’émetteur, obtenus en analysant les techniques de production des enregistrements commerciaux, et les modèles de récepteur qui sont au coeur du codage spatial paramétrique. A partir de cette mise en perspective nous présentons et étudions les trois approches évoquées plus haut. Pour l’approche purement paramétrique, nous montrons l’impossibilité d’arriver à la transparence pour la majorité des sources audios, nous menons une réflexion sur les représentations paramétriques et proposons des techniques afin de réduire le débit de leurs paramètres et d’améliorer la qualité audio. Ces améliorations passent par une meilleur segmentation du signal audio, basée sur les transitoires, sur des caractéristiques perceptives de certains indices spatiaux et sur une meilleur estimation des indices spatiaux. L’approche mixte étant récemment standardisée dans MPEG USAC, nous l’étudions en détail, puis nous proposons une nouvelle technique de codage qui exploite au mieux l’allocation du résidu aux bandes fréquentielles, lorsque celui-ci n’est pas utilisé sur l’ensemble de la bande passante du signal. Enfin, nous concluons en évoquant l’avenir du codage audio spatial généraliste et mettons l’accent sur l’importance de développer des techniques de classification et de segmentation audio pour optimiser le rapport qualité/débit<br>During the last ten years, technics for joint coding exploiting relations and redundancies between channels have been developped in order to further reduce the amount of information needed to represent multichannel audio signals.In this document, we focus on the coding of stereo audio signals where prior informations on the nature of sources in presence, their number or the manner they are spatialized is unknown. Such signals are actually the most representative in commercial records of music industry and in multimedia entertainment in general. To address the coding problematic of these signals, we study parametric and signal approaches, where both of them are often mixed.In this context, three types of approaches are used. The spatial parametric approach reduce the number of audio channels of the signal to encode and recreate the original number of channels from reduced channels and spatial parameters extracted from original channels. The signal approach keep the original number of channels, but encode mono signals, built from the combination of the original ones and containing less redundancies. Finally, the hybrid approach introduced in the MPEG USAC standard keep the two channels of a stereo signal, but one is a mono downmix and the other is a residual signal, resulting from a prediction on the downmix, where prediction parameters are encoded as side information.In this document, we first analyse the characteristics of a stereo audio signal coming from a commercial recording and the associated production techniques. This study lead us to consider the relations between the emitter parametric models, elaborated from our analysis of commercial recording production techniques, and the receiver models which are the basis of spatial parametric coding. In the light of these considerations, we present and study the three approaches mentioned earlier. For the parametric approach, we show that transparency cannot be achieved for most of the stereo audio signals, we have a reflection on parametric representations and we propose techniques to improve the audio quality and further reduce the bitrate of their parameters. These improvements are obtained by applying a better segmentation on the signal, based on the significant transient, by exploiting perceptive characteristics of some spatial cues and by adapting the estimation of spatial cues. As the hybrid approach has been recently standardized in MPEG USAC, we propose a full review of it, then we develop a new coding technique to optimize the allocation of the residual bands when the residual is not used on the whole bandwidth of the signal to encode. In the conclusion, we discuss about the future of the general spatial audio coding and we show the importance of developping new technics of segmentation and classification for audio signals to further adapt the coding to the content of the signal

Spel har förvandlats till en mainstream underhållningskälla och har utvecklats tillsammans med teknologin. Till en nivå som nyttjar en spelares alla sinnen för att fördjupa de i ett spel. Uppmärksamheten kring tillgänglighet inom spel har dock försvagats.Detta examensarbete undersöker de tillgängliga lösningarna som syftar till att hjälpa döva eller hörselskadade, främst när det gäller situationsmedvetenhet genom att ersätta ljud med en visuell representation. De i skrivande stund tillgängliga lösningarna jämförs sedan med resultaten i relaterad forskning och en undersökning som genomfördes för detta arbete. Målsättningen var att hitta vad som fungerade som en visuell representation av ljud, med undersökningssvaren som ger insikt i döva och hörselskadade individers perspektiv på lösningarna.Dessa resultat kan fungera som en referenspunkt för utvecklare som vill implementera en visuell representation av ljud eller liknande funktion i deras spel.<br>Video Games have turned into a mainstream source of entertainment and have evolved alongside technological improvements. To the point of being able to bring the player immersive gaming experiences that rely heavily on their senses. However, the attention to the accessibility aspects of video games has been lagging behind.This thesis explores the available solutions that aim to help Deaf or Hard of Hearing (DHH) players, primarily in terms of situational awareness by substituting audio with a visual representation. The currently available solutions are then compared with the findings in related research and a survey that was conducted for this paper. The objective was to find what worked as a visual representation of audio, with the survey responses providing insight into DHH players perspective.These findings can serve as a reference point for developers who want to implement a visual substitute for audio or a similar feature intheir game.

For humans, hearing is the second most important sense, after sight. Therefore, acoustic information greatly contributes to observing and analysing an area of interest. For this reason combining audio and video cues for surveillance enhances scene understanding and the observed events. However, when combining different sensors their measurements need to be correlated, which is done by either knowing the exact relative sensor alignment or learning a mapping function. Most deployed systems assume a known relative sensor alignment, making them susceptible to sensor drifts. Additionally, audio recordings are generally a mixture of several source signals and therefore need to be processed to extract a desired sound source, such as speech of a target person.In this thesis a generic framework is described that captures, indexes and extracts surveillance events from coordinated audio and video cues. It presents a dynamic joint-sensor calibration approach that uses audio-visual sensor measurements to dynamically and incrementally learn the calibration function, making the sensor calibration resilient to independent drifts in the sensor suite. Experiments demonstrate the use of such a framework for enhancing surveillance.Furthermore, a speech enhancement approach is presented based on a distributed network of microphones, increasing the effectiveness for acoustic surveillance of large areas. This approach is able to detect and enhance speech in the presence of rapidly changing environmental noise. Spectral subtraction, a single channel speech enhancement approach, is modified to adapt quickly to rapid noise changes of two common noise sources by incorporating multiple noise models. The result of the cross correlation based noise classification approach is also utilised to improve the voice activity detection by minimising false detection based on rapid noise changes. Experiments with real world noise consisting of scooter and café noise have proven the advantage of multiple noise models especially when the noise changes during speech.The modified spectral subtraction approach is then extended to real world scenarios by introducing more and highly non-stationary noise types. Thus, the focus is directed to implement a more sophisticated noise classification approach by extracting a variety of acoustic features and applying PCA transformation to compute the Mahalanobis distance to each noise class. This distance measurement is also included in the voice activity detection algorithm to reduce false detection for highly non-stationary noise types. However, using spectral subtraction in non-stationary noise environments, such as street noise, reduces the performance of the speech enhancement. For that reason the speech enhancement approach is further improved by using the sound information of the entire network to update the noise model of the detected noise type during speech. This adjustment considerably improved the speech enhancement performance in non-stationary noise environments. Experiments conducted under diverse real world conditions including rapid noise changes and non-stationary noise sources demonstrate the effectiveness of the presented method.

This explorative study investigates the role of audio-visual cues in user experience of virtual reality narratives. Using qualitative research methods, this study analyzes users’ experiences from their point of view and finds out what design factors contribute to their positive or negative experiences. Based on a thematic analysis of collected data, this study argues that when users are experiencing an immersive virtual reality narrative their curiosity drive them to look for clues in that virtual environment. If the virtual world provides well-designed audio-visual cues to guide their attention throughout the narrative then users feel immersion and spatial presence. On the contrary, lack of cues in a virtual environment keeps users looking straight ahead throughout the narrative, which results in boredom. Finally, excessive use of audio-visual cues makes users to keep switching their attention in multiple directions in fear of missing out something important, eventually resulting in their frustration and stress. This study will be useful for HCI researchers and narrative designers who are focusing their work in consumer oriented virtual reality applications.<br>Denna explorativa studie undersöker hur människor uppfattar upplevelser i mobila virtuella verkligheter och hur olika audiovisuella signaler i dessa miljöer påverkar upplevelserna. Med kvalitativa forskningsmetoder som omfattar observation, ”think aloud” samt semistrukturerade intervjuer, utforskar denna studie användarnas upplevelser från deras egen synpunkt och försöker att ta reda på vilka designfaktorer som bidrar till positiva eller negativa upplevelser. Med hjälp av tematisk analys av insamlad data hävdar denna studie att användare kommer in i ett fördjupat berättande utan att veta var man ska titta eller hur man ska gå vidare. Däremot så hjälper användarnas nyfikenhet dem att leta efter ledtrådar i miljön som gör att de kan komma vidare. Om den virtuella världen förser användaren med väldesignade audiovisuella signaler för att styra deras uppmärksamhet i berättelsen så kommer användaren in i ett flöde som möjliggör för en positiv upplevelse. Bristen på signaler i den virtuella miljön gör att användaren mestadels endast tittar rakt fram, medans ett överdrivet utnyttjande av signaler gör att de tittar sig omkring mer slumpartat, i rädsla för att missa något viktigt. I båda fallen kommer deras upplevelse att vara negativ.

Ces travaux de thèse portent sur la reconnaissance automatique du stress chez des humains en interaction dans des situations anxiogènes: prise de parole en public, entretiens et jeux sérieux à partir d'indices audio et visuels.Afin de concevoir des modèles de reconnaissance automatique du stress, nous utilisons : des indices audio calculés à partir de la voix des sujets, capturée par un micro cravate; et des indices visuels calculés soit à partir de l'expression faciale des sujets capturés par une webcam, soit à partir de la posture des sujets capturée par une Kinect. Une partie des travaux portent sur la fusion des informations apportées par les différentes modalités.L'expression et la gestion du stress sont influencées à la fois par des différences interpersonnelles (traits de personnalité, expériences passées, milieu culturel) et contextuelles (type de stresseur, enjeux de la situation). Nous évaluons le stress sur différents publics à travers des corpus de données collectés pendant la thèse: un public sociophobe en situation anxiogène, face à une machine et face à des humains; un public non pathologique en simulation d'entretien d'embauche; et un public non pathologique en interaction face à un ordinateur ou face au robot humanoïde Nao. Les comparaisons inter- individus, et inter-corpus révèlent la diversité de l'expression du stress.Une application de ces travaux pourrait être la conception d'outils thérapeutiques pour la maitrise du stress, notamment à destination des populations phobiques.Mots clé : stress, phobie sociale, détection multimodale du stress , indices audio du stress, indices faciaux du stress, indices posturaux du stress, fusion multimodale<br>This thesis focuses on the automatic recognition of human stress during stress-inducing interactions (public speaking, job interview and serious games), using audio and visual cues.In order to build automatic stress recognition models, we used audio cues computed from subjects' voice captured via a lapel microphone, and visual cues computed either form subjects' facial expressions captured via a webcam, or subjects' posture captured via a Kinect. Part of this work is dedicated to the study of information fusion form those various modalities.Stress expression and coping are influenced both by interpersonal differences (personality traits, past experiences, cultural background) and contextual differences (type of stressor, situation's stakes). We evaluated stress in various populations in data corpora collected during this thesis: social phobics in anxiety-inducing situations in interaction with a machine and with humans; apathologic subjects in a mock job interview; and apathologic subjects interaction with a computer and with the humanoid robot Nao. Inter-individual and inter-corpora comparisons highlight the variability of stress expression.A possible application of this work could be the elaboration of therapeutic software to learn stress coping strategies, particularly for social phobics.Key words: stress, social phobia, multimodal stress detection, stress audio cues, stress facial cues, stress postural cues, multimodal fusion

The purpose of this study was to investigate the effect of time-compressed narration and representational adjunct images on undergraduate college students' 1) ability to recall and recognize information in a multimedia learning environment, and 2) overall satisfaction with this type of learning environment. The goals of this research were to shed light on time-compression technology incorporated into multimedia learning environments, help fill the existing gap in the research literature by merging two disjoint bodies of research, and aid instructors and instructional designers to better understand time-compression technology while creating rigorous multimedia materials. This research was guided by the underlying principles of multimedia learning. The experiment was a 4 Audio Speeds (1.0 = normal vs. 1.5 = moderate vs. 2.0 = fast vs. 2.5 = fastest rate) x Adjunct Image (Image Present vs. Image Absent) factorial design. Audio speed and adjunct image both served as between subject conditions. Cued-recall, content recognition and learner satisfaction served as the dependent measures. Multimedia interventions were developed to execute this design. A total of 305 research participants were recruited from a public, southeastern university in the United States in this study. Fifty-five percent of the participants were male and 92% indicated that English was their primary language. Forty-nine percent of the participants were junior classification, 4% were freshman, 19% were sophomore, 26% were seniors, with the remaining indicating other. The median age of the participants was 22, and ranges in age from 18 to 53 years old. Data were analyzed using a series of factorial Analysis of Variance (ANOVA) procedures. Results showed statistically significant differences at 2.5 times the normal audio speed, in which performance on cued-recall and content recognition tasks was significantly lower than other audio speeds. Furthermore, representational adjunct images had a significant positive effect on cued-recall, but not content recognition. Participants in the normal audio speed and picture present groups were significantly more satisfied than other treatments. Recommendations for future research are provided as well as advice for instructors, instructional designers and learners interested in time-compression technology.

碩士<br>國立臺灣師範大學<br>資訊工程研究所<br>100<br>Most of the classrooms come with blackboards, and blackboards are widely used as a teaching prop in lecture video recordings. However, there are very few discussions about lecture video recordings that use blackboard as teaching prop concerning its multimedia semantics analysis. The article used a visual and optical based research method to explore speaker’s body languages and tone of speech in the blackboard lecture recordings, and how the amount of attention to pay in different segments of lecture recordings to enhance students’ learning. The visual analysis focused on semantics implied in speaker’s postures. The optical analysis focused on the variations of speaker’s speech emotions in his flow of teaching. The article proposed a speech emotion recognition model that divides speech emotions into five categories of happy, angry, bored, sad, and normal. The results of the analysis showed semantic intensity of the speaker and the importance of speakers teaching in different segments, and how students can learn more effectively with their variations in amount of attention according to the importance of speakers’ teaching throughout lecture video recordings.

Indiana University-Purdue University Indianapolis (IUPUI)<br>To access interactive systems, blind and visually impaired users can leverage their auditory senses by using non-speech sounds. The current structure of non-speech sounds, however, is geared toward conveying user interface operations (e.g., opening a file) rather than large theme-based information (e.g., a history passage) and, thus, is ill-suited to signify the complex meanings of primary learning material (e.g., books and websites). In order to address this problem, this dissertation introduces audemes, a new category of non-speech sounds, whose semiotic structure and flexibility open new horizons for facilitating the education of blind and visually impaired students. An experiment with 21 students from the Indiana School for the Blind and Visually Impaired (ISBVI) supports the hypothesis that audemes increase the retention of theme-based information. By acting as memory catalysts, audemes can play an important role in enhancing the aural interaction and navigation in future sound-based user interfaces. For this dissertation, I designed an Acoustic EDutainment INterface (AEDIN) that integrates audemes as a way by which to vividly anticipate text-to-speech theme-based information and, thus, act as innovative aural covers. The results of two iterative usability evaluations with total of 20 blind and visually impaired participants showed that AEDIN is a highly usable and enjoyable acoustic interface. Yet, designing well-formed audemes remains an ad hoc process because audeme creators can only rely on their intuition to generate meaningful and memorable sounds. In order to address this problem, this dissertation presents three experiments, each with 10 blind and visually impaired participants. The goal was to examine the optimal combination of audeme attributes, which can be used to facilitate accurate recognitions of audeme meanings. This work led to the creation of seven basic guidelines that can be used to design well-formed audemes. An interactive application tool (ASCOLTA: Advanced Support and Creation-Oriented Library Tool for Audemes) operationalized these guidelines to support individuals without an audio background in designing well-formed audemes. An informal evaluation conducted with three teachers from the ISBVI, supports the hypothesis that ASCOLTA is a useful tool by which to facilitate the integration of audemes into the teaching environment.

Virtual simulations and serious games (video game-based technologies applied to teaching and learning) have been incorporated in the teaching and training curricula of a large number of professions including medicine/surgery. Despite their benefits, there are open, fundamental issues regarding simulation quality, multi-modal cue interaction, and the resulting effect on visual quality perception and ultimately on knowledge transfer and retention. Here the results of a series of seven studies that examined the effect of background sound (contextually related and non-related with respect to the visual scene) on the perception of visual quality (defined with respect to texture resolution, polygon count) presented in stereoscopic and non-stereoscopic 3D. Results indicate that the perception of visual quality is dependent on ambient (background) sound. The results of these studies have implications for designers and developers of serious games who typically strive for high quality virtual worlds despite the computational burden associated with doing so. The results of these studies also bring us closer to understanding the role of quality, multi-modal interactions, and their effect on visual quality perception. This thesis is part of a larger effort in developing an understanding of virtual environment rendering quality, multi-modal interactions, user-specific factors and their effect on knowledge transfer and retention.<br>UOIT

碩士<br>國立成功大學<br>會計學系<br>104<br>This study examines the relationship between extreme decreases in CEO compensation and the audit fees charges by their audit firms. We propose that CEO pay cuts will increase the incentives to engage in high-risk activities and pose higher risk for auditors. To reduce audit risk to an acceptable level, auditors must exert additional audit effort, further leading to higher audit fees. Using S＆P 1500 non-financial and non-utility firms over the period 2000-2014(as of December 31, 2014), we find that CEO pay cuts are positively related to audit fees, suggesting that auditors perceive heightened audit risk associated with CEO pay cuts. We also find that the positive association between CEO pay cuts and audit fees is less pronounced in the case of firms with stronger corporate governance. Further analyses provide evidence that (1) CEO pay cuts led to longer ARL; (2) only Big 4 audit firms respond to CEO pay cuts in audit pricing decisions; (3) auditors take into account both equity-based and non-equity-based incentives in risk assessment and pricing decision; (4) after controlling for CEO forced turnover, CEO pay cuts are also positively related to audit fees.

碩士<br>東吳大學<br>會計學系<br>107<br>This paper examines the relationship between executive pay cuts and audit fees. In the case of separation of ownership and management rights, in order to reduce the information asymmetry between shareholders and senior management, it is common to link the executive compensation with corporate performance. However, when the corporate performance is not good and the board of directors lowers the salary of senior management to trigger their efforts, the senior management has a strong incentive to report better corporate performance as quickly as possible, which may increase the likelihood that the senior management will resort to manipulating the financial reports. Will that increase the audit risk and audit fees? Using a sample of Taiwanese listed firms excluding finance and insurance industry from 2014 to 2016. We found that the reduction of senior management compensation was 42.23% of the total sample, and the rate was increasing year by year. In addition, in the case of a decrease in total compensation or a decrease in base pay, the majority were reduced by less than 10%, accounting for 42.14% of total compensation and 44.43% of base pay, respectively. Therefore, a 10% reduction in compensation can be regarded as a substantial pay cuts in Taiwanese listed firms. The empirical results show that the total compensation or base pay of the senior management is reduced by more than 10%, the audit fees will be higher in next period, which is consistent with the expectation of our research hypothesis.

abstract: Sound localization can be difficult in a reverberant environment. Fortunately listeners can utilize various perceptual compensatory mechanisms to increase the reliability of sound localization when provided with ambiguous physical evidence. For example, the directional information of echoes can be perceptually suppressed by the direct sound to achieve a single, fused auditory event in a process called the precedence effect (Litovsky et al., 1999). Visual cues also influence sound localization through a phenomenon known as the ventriloquist effect. It is classically demonstrated by a puppeteer who speaks without visible lip movements while moving the mouth of a puppet synchronously with his/her speech (Gelder and Bertelson, 2003). If the ventriloquist is successful, sound will be “captured” by vision and be perceived to be originating at the location of the puppet. This thesis investigates the influence of vision on the spatial localization of audio-visual stimuli. Participants seated in a sound-attenuated room indicated their perceived locations of either ISI or level-difference stimuli in free field conditions. Two types of stereophonic phantom sound sources, created by modulating the inter-stimulus time interval (ISI) or level difference between two loudspeakers, were used as auditory stimuli. The results showed that the light cues influenced auditory spatial perception to a greater extent for the ISI stimuli than the level difference stimuli. A binaural signal analysis further revealed that the greater visual bias for the ISI phantom sound sources was correlated with the increasingly ambiguous binaural cues of the ISI signals. This finding suggests that when sound localization cues are unreliable, perceptual decisions become increasingly biased towards vision for finding a sound source. These results support the cue saliency theory underlying cross-modal bias and extend this theory to include stereophonic phantom sound sources.<br>Dissertation/Thesis<br>Masters Thesis Bioengineering 2015