This thesis introduces the idea of two-level type theory, an extension of Martin-Löf type theory that adds a notion of strict equality as an internal primitive. A type theory with a strict equality alongside the more conventional form of equality, the latter being of fundamental importance for the recent innovation of homotopy type theory (HoTT), was first proposed by Voevodsky, and is usually referred to as HTS. Here, we generalise and expand this idea, by developing a semantic framework that gives a systematic account of type formers for two-level systems, and proving a conservativity result relating back to a conventional type theory like HoTT. Finally, we show how a two-level theory can be used to provide partial solutions to open problems in HoTT. In particular, we use it to construct semi-simplicial types, and lay out the foundations of an internal theory of (∞, 1)-categories.

Human-agent collectives (HACs) are collaborative relationships between humans and software agents that are formed to meet the individual and collective goals of their members. In general, different members of a HAC should have differing degrees of autonomy in determining how a goal is to be achieved, and the degree of autonomy that should be enjoyed by each member of the collective varies with context. This thesis explores how norms can be used to achieve context sensitive flexible autonomy in HACs. Norms can be viewed as defining standards of ideal behaviour. In the form of rules and codes, they are widely used to coordinate and regulate activity in human organisations, and more recently they have also been proposed as a coordination mechanism for multi-agent systems (MAS). Norms therefore have the potential to form a common framework for coordination and control in HACs. The thesis develops a novel framework in which group and individual norms are used to specify both the goal to be achieved by a HAC and the degree of autonomy of the HAC and/or of its members in achieving a goal. The framework allows members of a collective to create norms specifying how a goal should (or should not) be achieved, together with sanctions for non-compliance. These norms form part of the decision making context of both the humans and agents in the collective. A prototype implementation of the framework was evaluated using the Colored Trails test-bed in a scenario involving mixed human-agent teams. The experiments confirmed that norms can be used for coordination of HACs and to facilitate context related flexible autonomy.

This thesis presents a practice-led research investigation into ways of designing more experiential and evocative interactions with data that relates to our experiences whereby less explicit, more intrinsic and aesthetic relationships are made between people, objects and data. I argue that the utilitarian values and instrumental approach behind the design of most systems that mediate our personal autobiographical data, while important, are not appropriate for more emotional forms of remembering. Therefore, systems are needed that cater specifically to modes of remembering such as reminiscence and reflection. By learning from our material encounters with memory, there are rich opportunities for design to uncover the latent values that might exist in biographical data. To articulate the design rationale of the thesis, I describe two existing design projects: the Digital Slide Viewer and Photobox. These provide some design principles that offer guidance in making memory data physical so as to encourage meaningful material practices, and ways that interactions might be designed to promote reflection. After exploratory interviews to gather insight into the ways people associate meaning with objects a set of designed provocations were produced. The Poker Chip sought to understand the ways that the material form of an object connects to its meaning, while The Bowl investigates how the actions we might use to make these meaningful objects might in themselves be meaningful. The final designed provocation takes ideas from its predecessors, and puts them into practice with a data driven system. By responding to live data from real earthquakes, the Earthquake Shelf creates a tangible rendition that, by damaging objects, leaves behind material evidence of a remote event. During a long-term field deployment, connection between the objects on the shelf and the participant’s memories proved illusive, but the shelf itself provided a viscerally real connection to a past experience. The outcome of this thesis then is to articulate Experiential Manufacturing; a position on the design of technologies intended to mediate more emotional forms of memory, such that they can create more compelling relations between data, people, and things. It does this by first opening and exploring a design space based on alternative values for designing technologies of reminiscence that mediate our life experiences. By prioritizing the aesthetic elements of the experiences, rather than focusing on the data that describes it, this thesis explores the potential of material, liveness and slowness to create systems that mediate our experience data in more evocative and emotionally valuable ways. It then presents this position as a set of thematic values, or Strong Concepts at the heart of Experiential Manufacturing.

With the growth of ubiquitous computing, it is becoming increasingly easy to carry out work from anywhere, using a simple computing device that can connect you to the internet. Governments, policy makers, not-for-profit and scientific organizations have been reaching out to members of the general public - citizens, popularly known as the ‘crowd’, to get their ideas, opinions and expertise on various matters. This phenomenon of using the expertise of the ‘crowd’ for different purposes is called ‘crowdsourcing’. For sometime now businesses have been looking for new ways of saving money, beyond outsourcing, for their organizations; and have thus started reaching out to the crowd, through various platforms online to get access to a cheap, mobile workforce that is presumably available round the clock. Employing the crowd comes with massive benefits for such organisations that choose to use them: the crowd-workers serve as contractors or daily workers, who do not receive standard employee benefits such as holiday pay and insurance, as well as, pay for their own primary resources – the internet, computer, infrastructural and subsistence costs. There is also no current legislation that provides guidelines regarding such type of work, although there are quite a few researchers and advocacy groups now trying to change this. For the workers, crowdsourcing provides opportunities to make money, get exposure towards developing skills, learning to work and see a world outside their own all thanks to growth in tele-communication technologies and unstable employment patterns around the world. And although there is a lot of discourse surrounding crowdsourcing and crowdwork, particularly due to the legal aspect of such work, not much is understood about the work and the workers. Questions about this workforce remain unanswered such as: why does the crowd choose to do this type of work, how do they find these crowdsourcing platforms and crowdsourced jobs, what do they look for in the jobs they pick, how they organized their activities (both work and non-work), what tools and technologies they used, what might their concerns be as workers, how do they relate to requesters and the work platform? This thesis aims to provide insights into the work of crowdwork, what entails ‘doing crowdwork’, from the perspective of the workers who partake in crowdsourced work through online platforms. The thesis presents insights from an ethnographic study conducted in India through the summer of 2013, of crowdworkers, with a particular focus on Amazon Mechanical Turk (AMT) as the principle site for work. The naturalistic data was collected from virtual and in-person interviews as well as observations of crowdworkers in their places of work and dwelling, and analysed with an ethnomethodological orientation to data, to uncover the local methods of the workers in their own words, to provide more information about this understudied cohort. Learning about crowdwork and the workers is important because this type of work has potential from an organizational perspective; a variety of relatively low-skilled work such as data entry processing, tagging, information verification, transcription and translation are being (and could be) crowdsourced by medium and large organisations. Hence this thesis makes contributions to the fields of human computation, CSCW, HCI and crowdsourcing by bringing forth insights into ‘doing crowdwork’ and ‘being a crowdworker’, which might help parties interested in using, applying or designing for crowdsourced work and crowdsourcing platforms, as well as, researchers and designers interested in this field. The contributions of the thesis include: • Uncovering the heterogeneity in the motives of turkers: what motivates workers to work on platforms like AMT, and why they choose to continue their engagement with such work and platforms. • The features of the crowdsourcing platform: what made a platform attractive to the turkers? For instance, features such as ease of use and flexibility in choosing work, played an important role in crowdsourcing. • The social nature of work: although crowdwork is highly individualized and atomic, the nature of work itself was very social. Most workers found that they needed help for one thing or the other and found online resources such as forums and Facebook groups to get support or information regarding work and personal life. • Invisible work and constant contingency management undertaken by the crowdworkers: Workers had to find and do work while managing contingencies that were created due to the opaque nature of the platform studied, AMT; requiring them to seek help externally, e.g by means of browser plug-ins, to help them work around this opacity, at the same time, creating more unpaid work for them.

No description available.

Brain-computer music interfacing (BCMI) presents a novel approach to music making, as it requires only the brainwaves of a user to control musical parameters. This presents immediate benefits for users with motor disabilities that may otherwise prevent them from engaging in traditional musical activities such as composition, performance or collaboration with other musicians. BCMI systems with active control, where a user can make cognitive choices that are detected within brain signals, provide a platform for developing new approaches towards accomplishing these activities. BCMI systems that use passive control present an interesting alternate to active control, where control over music is accomplished by harnessing brainwave patterns that are associated with subconscious mental states. Recent developments in brainwave measuring technologies, in particular electroencephalography (EEG), have made brainwave interaction with computer systems more affordable and accessible and the time is ripe for research into the potential such technologies can offer for creative applications for users of all abilities. This thesis presents an account of BCMI development that investigates methods of active, passive and hybrid (multiple control methods) control that include control over electronic music, acoustic instrumental music, multi-brain systems and combining methods of brainwave control. In practice there are many obstacles associated with detecting useful brainwave signals, in particular when scaling systems otherwise designed for medical studies for use outside of laboratory settings. Two key areas are addressed throughout this thesis. Firstly, improving the accuracy of meaningful brain signal detection in BCMI, and secondly, exploring the creativity available in user control through ways in which brainwaves can be mapped to musical features. Six BCMIs are presented in this thesis, each with the objective of exploring a unique aspect of user control. Four of these systems are designed for live BCMI concert performance, one evaluates a proof-of-concept through end-user testing and one is designed as a musical composition tool. The thesis begins by exploring the field of brainwave detection and control and identifies the steady-state visually evoked potential (SSVEP) method of eliciting brainwave control as a suitable technique for use in BCMI. In an attempt to improve signal accuracy of the SSVEP technique a new modular hardware unit is presented that provides accurate SSVEP stimuli, suitable for live music performance. Experimental data confirms the performance of the unit in tests across three different EEG hardware platforms. Results across 11 users indicate that a mean accuracy of 96% and an average response time of 3.88 seconds are attainable with the system. These results contribute to the development of the BCMI for Activating Memory, a multi-user system. Once a stable SSVEP platform is developed, control is extended through the integration of two more brainwave control techniques: affective (emotional) state detection and motor imagery response. In order to ascertain the suitability of the former an experiment confirms the accuracy of EEG when measuring affective states in response to music in a pilot study. This thesis demonstrates how a range of brainwave detection methods can be used for creative control in musical applications. Video and audio excerpts of BCMI pieces are also included in the Appendices.

Humans spend a large amount of their time interacting with computers of one type or another. However, computers are emotionally blind and indifferent to the affective states of their users. Human-computer interaction which does not consider emotions, ignores a whole channel of available information. Faces contain a large portion of our emotionally expressive behaviour. We use facial expressions to display our emotional states and to manage our interactions. Furthermore, we express and read emotions in faces effortlessly. However, automatic understanding of facial expressions is a very difficult task computationally, especially in the presence of highly variable pose, expression and illumination. My work furthers the field of automatic facial expression tracking by tackling these issues, bringing emotionally aware computing closer to reality. Firstly, I present an in-depth analysis of the Constrained Local Model (CLM) for facial expression and head pose tracking. I propose a number of extensions that make location of facial features more accurate. Secondly, I introduce a 3D Constrained Local Model (CLM-Z) which takes full advantage of depth information available from various range scanners. CLM-Z is robust to changes in illumination and shows better facial tracking performance. Thirdly, I present the Constrained Local Neural Field (CLNF), a novel instance of CLM that deals with the issues of facial tracking in complex scenes. It achieves this through the use of a novel landmark detector and a novel CLM fitting algorithm. CLNF outperforms state-of-the-art models for facial tracking in presence of difficult illumination and varying pose. Lastly, I demonstrate how tracked facial expressions can be used for emotion inference from videos. I also show how the tools developed for facial tracking can be applied to emotion inference in music.

This thesis investigates the composition of original adaptive musical soundtracks for locative walking activities such as cultural visiting, mobile games and urban, and nature walks; those semi-formal orchestrated walking experiences. This investigation views the ‘soundtrack’ – similarly to those typically found in ‘display’ media experiences such as films and computer games – as an accompaniment rather than the principal feature of the experience. Thus its role is to support and enhance the walking ‘narrative’. In order to best achieve this the soundtrack needs to be heard as congruent and embedded into the activity. This thesis is oriented towards the field of Human Computer Interaction (HCI) and also at composers of such soundtracks; reflecting the thesis’s intention to develop guidelines for locative soundtrack composition that draws upon detailed mappings between musical structure and spatial structure that drives the creation and experience of both. An initial study explored how a group of participants interpreted and responded to different musical features which adapted to their walking routes. This study revealed that participants formed a set of connections between the physical space and the musical structures. These findings were then used to motivate an in-the-field design, composition and deployment of a large-scale adaptive soundtrack for a public cultural visiting experience, which was subsequently experienced by a group of visitors. This study revealed that the soundtrack was considered congruent with the activity and was deeply engaging, quite distinct from a typical visit to this site. These research activities are reflected upon and discussed to distil a framework of guidelines for composing locative soundtracks that is generalizable to other settings and activities.

This thesis aims to better represent a framework for asynchrony. Traditional asynchronous models, particularly those used to simulate cellular automata, have used stochasticity or randomness to generate update times. We claimthat, while they may make good representations of their application, such asynchronousmethods rid themodel of the essence of interesting asynchronous processes. Thus, we attempt to better harness the aspects internal to the decision process of such discretely dynamic cells as those in cellular automata.We propose the maxmin-m model as a suitable model for the asynchronous computation of cellular automata. The model uses maxmin-plus algebra, a special case of which is max-plus algebra. This algebra arises naturally from the cellular automaton requirement that a cell receives the state of its neighbours before updating. The maxmin-m model allows each cell to update after it receives m out of a possible n neighbours' states.The max-plus model shows that, while update times may be asynchronous in real time, there is no loss of information, since the corresponding asynchronous process is bijectively related to the synchronous model. In turn, the cellular automaton output, measured by the Shannon and word entropies, is shown to vary little from the synchronous model. Moreover, this type of asynchrony is simple, i.e. it is deterministically obtained due to the linearity of max-plus algebra.Indeed, the maxmin-m model is also shown to be deterministic and always reaches periodic behaviour. In the long time limit, this model is shown to be represented by a max-plus model, supporting its determinism further. Consequently, the complexity of such a model may be thought to be limited. However, we show through large scale experiments that the case where m is approximately n/2 generates most complex behaviour in terms of large periods and transients to the aforementioned periodic orbits. In particular, the complexity is empirically shown to obey a bell form as a function of m (where m ranges from 1 to n). The resulting cellular automaton simulations indicate a correspondence from the complexity of the update times. Therefore, cellular automaton behaviour may be predictable with the type of asynchrony employed in this thesis.

This thesis develops a theoretical framework to evaluate XML retrieval. XML retrieval deals with retrieving those document parts that specifically answer a query. It is concerned with using the document structure to improve the retrieval of information from documents by only delivering those parts of a document an information need is about. We define a theoretical evaluation methodology based on the idea of `aboutness' and apply it to XML retrieval models. Situation Theory is used to express the aboutness proprieties of XML retrieval models. We develop a dedicated methodology for the evaluation of XML retrieval and apply this methodology to five XML retrieval models and other XML retrieval topics such as evaluation methodologies, filters and experimental results.