Many virtual environments like interactive computer games, educational software or training simulations make use of speech to convey important information to the user. These applications typically present a combination of background music, sound effects, ambient sounds and dialog simultaneously to create a rich auditory environment. Since interactive virtual environments allow users to roam freely among different sound producing objects, sound designers do not always have exact control over what sounds a user will perceive at any given time. This dissertation investigates factors that influence the perception of speech in virtual environments under adverse listening conditions. A virtual environment was created to study hearing performance under different audio-visual conditions. The two main areas of investigation were the contribution of "spatial unmasking" and lip animation to speech perception. Spatial unmasking refers to the hearing benefit achieved when the target sound and masking sound are presented from different locations. Both auditory and visual factors influencing speech perception were considered. The capability of modern sound hardware to produce a spatial release from masking using real-time 3D sound spatialization was compared with the pre-computed method of creating spatialized sound. It was found that spatial unmasking could be achieved when using a modern consumer 3D sound card and either a headphone or surround sound speaker display. Surprisingly, masking was less effective when using real-time sound spatialization and subjects achieved better hearing performance than when the pre-computed method was used. Most research on the spatial unmasking of speech has been conducted in pure auditory environments. The influence of an additional visual cue was first investigated to determine whether this provided any benefit. No difference in hearing performance was observed when visible objects were presented at the same location as the auditory stimuli. Because of inherent limitations of display devices, the auditory and visual environments are often not perfectly aligned, causing a sound-producing object to be seen at a different location from where it is heard. The influence of audio-visual integration between the conflicting spatial information was investigated to see whether it had any influence on the spatial unmasking of speech in noise. No significant difference in speech perception was found regardless of whether visual stimuli was presented at the correct location matching the auditory position, at a spatially disparate location from the auditory source. Lastly the influence of rudimentary lip animation on speech perception was investigated. The results showed that correct lip animations significantly contribute to speech perception. It was also found that incorrect lip animation could result in worse performance than when no lip animation is used at all. The main conclusions from this research are: That the 3D sound capabilities of modern sound hardware can and should be used in virtual environments to present speech; Perfectly align auditory and visual environments are not very important for speech perception; Even rudimentary lip animation can enhance speech perception in virtual environments.

There are a growing number of mobile phones being used in developing contexts, such as Africa. A large percentage of these phones have the capability to take photographs and transmit them freely using Bluetooth. In order to provide people with media on their mobile phones public displays are becoming more common. Three problems with current public displays – cost, security and mobility – are discussed and system proposed that uses a mobile phone as a server. Media is displayed on specially designed paper posters, which users can photograph using their mobile phones. The resulting photographs are sent, via Bluetooth, to the server, which analyses them in order to locate a specially designed barcode, representing the media, which is then decoded and the requisite media returned to the user. Two barcoding systems are tested in laboratory conditions, and a binary system is found to perform best. The system is then deployed on a campus transportation system to test the effects of motion. The results show that the system is not yet ready for deployment on moving transport.

The preferred method of communication amongst Deaf people is that of sign language. There are problems with the video quality when using the real-time video communication available on mobile phones. The alternative is to use text-based communication on mobile phones, however findings from other research studies show that Deaf people prefer using sign language to communicate with each other rather than text. This dissertation looks at implementing a gesture-based interface for an asynchronous video communication for Deaf people. The gesture interface was implemented on a store and forward video architecture since this preserves the video quality even when there is low bandwidth. In this dissertation three gesture-based video communication prototypes were designed and implemented using a user centred design approach. These prototypes were implemented on both the computer and mobile devices. The first prototype was computer based and the evaluation of this prototype showed that the gesture based interface improved the usability of sign language video communication. The second prototype is set up on the mobile device and it was tested on several mobile devices but the device limitation made it impossible to support all the features needed in the video communication. The different problems experienced on the dissimilar devices made the task of implementing the prototypes on the mobile platform challenging. The prototype was revised several times before it was tested on a different mobile phone. The final prototype used both the mobile phone and the computer. The computer served to simulate a mobile device with greater processing power. This approach simulated a more powerful future mobile device capable of running the gesture-based interface. The computer was used for video processing but to the user it was as if the whole system was running on the mobile phone. The evaluation process was conducted with ten Deaf users in order to determine the efficiency and usability of the prototype. The results showed that the majority of the users were satisfied with the quality of the video communication. The evaluation also revealed usability problems but the benefits of communicating in sign language outweighed the usability difficulties. Furthermore the users were more interested in the video communication on the mobile devices than on the computer as this was a much more familiar technology and offered the convenience of mobility.

Chongilala – a long time ago – says Mama Rhoda of Adiedo, Kenya. She looks deeply into our eyes. We record her rhythms and rhymes as she sings and tells a story about her grandparents. She shows us the exact spot where her great-grandfathers and his friends used to sit and drink and how her grandmother used to dance. This thesis situates digital storytelling in rural African communities to enable rural people, like Mama Rhoda, to record and share their stories and to express their imaginations digitally. We explore the role of design, and the methods and perspectives designers need to take on to design across cultures and to understand the forms and meanings behind rural African interpretations of digital storytelling. These perspectives allow us to 'unconceal' how our Western storytelling traditions have influenced design methods and obscure the voices of ‘other’ cultures. By integrating ethnographic insights with previous experiences of designing mobile digital storytelling systems, we implement a method using cell-phones to localize storytelling and involve rural users in de- sign activities – probing ways to incorporate visual and audio media in storytelling. Products from this method help us to generate design ideas for our system, most notably flexibility. Leveraging this prototype as a probe and observing villagers using it in two villages in South Africa and Kenya, we report on situated use of our prototype and discuss, and relate to usage, the insights we gathered on our prototype, the users, their needs, and their context. We use these insights to uncover further implications for situating digital storytelling within those communities and reflect on the importance of spending time in-situ when designing across cultures. Deploying our prototype through an NGO, we stage first encounters with digital storytelling and show how key insiders can introduce the system to a wider community and make it accessible through their technical and social expertise. Our mobile digital storytelling system proved to be both useable and useful and its flexibility allowed users to form their own interpretations of digital storytelling and (re)appropriate our system to alternative ends. Results indicate that our system accommodates context and that storytelling activities around our system reflect identity. Our activities in communities across Africa also show that our system can be used as a digital voice that speaks to us, by allowing users to express themselves – through digital stories – in design.

Digital libraries (DLs) represent an important evolutionary step towards accessing structured digital information. DLs are often built from scratch or by using proprietary monolithic software that is often difficult to customise and extend to meet changing requirements. Researchers are beginning to realise that this is not an ideal solution and as a result, are creating component suites and accompanying protocols to encourage the creation of modular DLs. Despite the introduction of component models, it is not immediately apparent how they can be seamlessly assembled to produce diverse, yet fully functional, component-based digital library systems without knowledge of the underlying protocols. This dissertation presents a graphical user interface and its associated framework for creating DL systems from distributed components, consequently shielding DL architects from the complexity of using components models and taking advantage of the inherent benefits of the component programming paradigm. The framework introduced in this dissertation was designed to be generic enough to be adopted for the assembly of a variety of component-based systems over and beyond the digital library community. After being tested on over thirty inexperienced users and modelling a number of existing DL systems, graphically assembling distributed components has been shown to be a viable approach to simplify the creation of modular DLs from a pool of heterogeneous components.

Music Information Retrieval (MlR) is the interdisciplinary science of retrieving information from music and includes influences from different areas, like music perception and cognition, music analysis, signal processing, music indexing and information retrieval [Futrelle & Downie, 2003]. To produce the most efficient MlR systems, test-beds are commonly used to test different combinations of parameters against each other. The purpose of this dissertation was to investigate the composition of algorithms for MlR systems by constructing an interface that could form part of a test-bed. It differs from other interfaces and frameworks that are used in MlR test-beds because it is focused on small scale test-beds. MIRMaid is an acronym for Music Information Retrieval Modular aid and is an interface that allows different content based retrieval tasks to be compared against each other to find optimal combinations of retrieval parameters for specialised problem domains. The dissertation describes the process of how the MIRMaid interface was developed, modified and refined. A big challenge was to design the user experiments in a way that considered potential users of the interface while using the test subjects I had at my disposal. I decided to use the simplest queries to highlight basic similarities between novice and potential expert users. The performance of the interface was judged by user ratings on a questionnaire. The interface performed reasonably well with expert users and novice users. Despite these results there were a few interesting observations that were returned from the user experiments related to the experiment design and the task explanations. Some suggestions are also provided for extending the interface to allow it to be used with other types of data. The possibility is also investigated for using the interface as a tool for simplifying the process of integrating modules from different sources.

Systems to annotate online content are becoming increasingly common on the World Wide Web. While much research and development has been done for interfaces that allow users to make and view annotations, few annotation systems provide functionality that extends beyond this and allows users to also manage and process collections of existing annotations. Siyavula Education is a social enterprise that publishes high school Maths and Science textbooks online. The company uses annotations to collate collaborator and volunteer feedback (corrections, opinions, suggestions) about its books at various phases in the book-writing life cycle. Currently the company captures annotations on PDF versions of their books. The web-based software they use allows for some filtering and sorting of existing annotations, but the system is limited and not ideal for their rather specialised requirements. In an attempt to move away from a proprietary, PDF-based system Siyavula implemented annotator (http://okfnlabs.org/annotator/), software which allowed for the annotation of HTML pages. However, this software was not coupled with a back-end interface that would allow users to interact with a database of saved annotations. To enable this kind of interaction, a prototype interface was designed and is presented here. The purpose of the interface was to give users new and improved functionality for querying and manipulating a collection of web-based annotations about Siyavula’s online content. Usability tests demonstrated that the interface was successful at giving users this new and necessary functionality (including filtering, sorting and searching) to process annotations. Once integrated with front-end software (such as Annotator) and issue tracking software (such as GitHub) the interface could form part of a powerful new tool for the making and management of annotations on the Web.

The Internet has potential to deliver information to Web users that have no other way of getting to those resources. However, information on the Web is scattered without any proper semantics for classifying them and thus this makes information discovery difficult. Thus, to ease the querying of this huge bin of information, developers have built tools amongst which are the search engines and Web directories. However, for these tools to give optimal results, two factors need to be given due importance: the users’ ability to use these tools and the bandwidth that is present in these environments. Unfortunately, after an initial study, none of these two factors were present in Mauritius where low bandwidth prevails. Hence, this study helps us get a better idea of how users use the search tools. To achieve this, we designed a survey where Web users were asked about their skills in using search tools. Then, a jump page using the search boxes of different search engines was developed to provide directed guidance for effective searching in low bandwidth environments. We then conducted a further evaluation, using a sample of users to see if there were any changes in the way users access the search tools. The results from this study were then examined. We noticed that the users were initially unaware about the specificities of the different search tools thus preventing efficient use. However, during the survey, they were educated on how to use those tools and this was fruitful when a further evaluation was performed. Hence the efficient use of the search tools helped in reducing the traffic flow in low bandwidth environments.

Many universities, libraries, government organisations and companies are implementing digital repositories to collect, preserve, administer and distribute their collections via the World Wide Web. In the process of building these digital archives and collections, images such as maps are often are captured in an uncompressed, high-resolution format to preserve as much detail as possible. This process, of high-resolution archiving gives rise to the problem of providing the end-user with access to these large (high-resolution) images, such as maps. This dissertation investigates methods of storing and delivering large images over the Internet while limiting the amount of data being transferred; and also documents efforts to incorporate large image support within the DSpace platform. An end-user usability study of various large image support solutions was conducted to establish how current digital repository large image solutions compared to commercial large image solutions. The study showed that the commercial large image solutions were superior to current digital repository solutions. A prototype large image solution was developed with a specific aim to provide DSpace with mechanisms to import and deliver large images in a bandwidth-conscious manner. It was found that by implementing and extending currently available open source large image processing software, large image support could be provided to the DSpace platform with minimal or no modification to the DSpace source code. An end user evaluation study was conducted to establish the usability and effectiveness of the prototype large image support solution. It was found that the prototype system provided an easy to use solution that provides DSpace with an effective large image archiving and delivery mechanism.

Open access and open resources have gained much attention from the world in the last few years. The interest in sharing information freely by the use of the World Wide Web has grown rapidly in many different fields. Now, information is available in many different data forms because of the continuous evolution in technology. The main objective of this thesis is to provide content creators and educators with a solution that simplifies the process of depositing into digital repositories. We created a desktop tool named ORchiD, Open educational Resources Depositor, to achieve this goal. The tool encompasses educational metadata and content packaging standards to create packages while conforming to a deposit protocol to ingest resources to repositories. A test repository was installed and adapted to handle Open Educational Resources. The solution proposed is centered on the front-end application which handles the complex objects on the user desktop. The desktop application allows the user to select and describe his/her resource(s) then creates the package and forwards it to the specified repository using the deposit protocol. The solution is proved to be simple for users but also in need of further improvements specifically in association to the metadata standard presented to user.