/library/oar/handle/123456789/11958 2025-11-06T15:11:40Z /library/oar/handle/123456789/78357 Title: A coarticulation model for articulatory speech synthesis Abstract: The state-of-the-art techniques for speech synthesis rely either on concatenation of acoustic units taken from a vast pre-recorded speech database noting the relevant linguistic information or on statistical generation of the necessary acoustic parameters and using a speech production model. These approaches yield synthesis of good quality, but are purely technical solutions which bring no or very little information about the acoustics of speech or about how the articulators (mandible, tongue, lips, velum...) are controlled. In contrast, the articulatory approach generates the speech signal from the vocal tract shape and its modelled acoustic phenomena. The vocal tract deformation control comprises slow anticipation of the main constriction and fast and imperatively accurate aiming for consonants. The system predicts the sequence of vocal tract consecutive configurations from a sequence of phonemes of the French language to be articulated and a model of the coarticulation effects in it. We use static magnetic resonance imaging (MRI) captures of the vocal tract shape when producing phonemes in various contexts, thus following an approach by Birkholz (2013). The evaluation of the model is done both on the animated graphics representing the vocal tract shape evolution (how natural and efficient the movement is) and on the synthesised speech signals that are perceptively and-in terms of formants-qualitatively compared to identical utterances made Ly a human. Our results show that there are a lot of effects in the dynamic process of speech that manage to be reproduced by manipulating solely static data. We discuss generation of pure vowels, vowel-to-vowel and vowel-consonant-vowel transitions, and articulators' behaviour in phrases, report which acoustic properties have been rendered correctly and what could be the reasons for the system to fail to produce the desired result in other cases, and ponder how to reduce the after-effects of target-oriented moves to obtain a more gesture-like motion. Description: M.SC.ARTIFICIAL INTELLIGENCE 2016-01-01T00:00:00Z /library/oar/handle/123456789/72835 Title: Behaviour mining for personalised desktop tool-support Abstract: It is natural for individuals to think about their work in terms of tasks, where a task could be the documents that they are working on or with, and/or the directories containing documents related to the same task. But directories do not necessarily contain all of the related documents, because documents might be emails and web pages, which are harder to place into the same directory. Furthermore, individuals are multitaskers and tasks get interrupted. This results in task-switching and the eventual resumption of some task (possibly the same one). Although different applications provide tools to support individuals to manage their information space, these tools fall short in supporting individuals when they need to keep and re-find documents that are part of their task or when a task-switch occurs. Task-keeping and re-finding (and/or resuming) with the current tool-support philosophy is both time-consuming and limited since it does not reflect the task concept. In contrast to a myriad of other approaches, this thesis considers task-keeping as a process that keeps track of changing tasks by identifying which documents belong to which tasks and when a task-switch occurs. An attempt is made to automatically identify the documents that belong to a task by solely relying on the user’s switching and re-visitation behaviour. In this way the process aims to reduce the keeping time without introducing new interruptions. Prior to addressing the problem, an experiment is conducted in a controlled environment with 22 participants to collect ground-truth task-related data. This dataset is later used to evaluate the task-keeping solution. It is extensively analysed from different perspectives using a visual-analytics tool that we built (called PiMx), to draw up the design requirements for the incremental density-based graph-clustering algorithm iDeTaCt. The algorithm is evaluated and extended and a marked improvement in its performance registered. A usability study is also performed with 15 participants over a five-day period using a prototype task-re-finding and resumption tool called PiMxT that uses iDeTaCt to automatically keep tasks. Both qualitative and quantitative feedback are solicited and analysed to verify the usefulness of the approach. The results show that the time to re-find and resume tasks with PiMxT is reduced by almost a half in the majority of the cases considered and that there is considerable potential behind this combined approach to task-keeping, re-finding and resumption. Description: PH.D.ARTIFICIAL INTELLIGENCE 2016-01-01T00:00:00Z /library/oar/handle/123456789/18516 Title: Monitorability of contracts for web services Abstract: Web services typically consist of two types of components, servers and clients, which interact with each other through service interactions. A server can be seen as a collection of services that a client invokes in order to reach a successful state. A server can be described in terms of a contract, which defi nes the service interactions that it offers. Dually, a client may also be portrayed by a contract, describing sequences of interactions that it expects to conduct with a server. In a dynamic service discovery setting, where clients search for compatible services with whom to interact, a server contract may be advertised by a server as its specification. A server may inadvertently or maliciously advertise a contract which it does not implement. Although static-based techniques can be employed to verify whether a server actually implements its advertised contract or not, there are settings where static verifi cation cannot be used. Furthermore, a client may decide not to trust a server. In such cases, the client is forced to verify the behaviour of the server at runtime. This scenario may be viewed as an instance of Runtime Veri fication, where a pertinent question is whether contracts can be monitored for adequately at runtime, otherwise stated as the monitorability of contracts. In general, not all specifications can be verified in a correct manner at runtime. In this dissertation, we set up to investigate this problem. We consider a language of contracts describing both clients and servers, together with a formal notion of \agreement" amongst these two types of contracts. We then develop a formal monitoring framework where we instrument servers with our monitors. We de fine monitor properties that relate monitors to server specifications that are de fined using contracts. One such property determines whether the conclusion reached by a monitor is correct wrt. a specification contract. Another property states that a monitor must be able to reach a conclusion about the server. In other words, it must be able to tell whether the server is implementing a specification or not. These properties are then used to study the notion of monitorability of contracts by using the newly created monitor language to defi ne an automatic synthesis from contracts to monitors. By using this synthesis, we show whether our contract language can create monitors which satisfy these properties. Description: M.SC.COMPUTER SCIENCE 2016-01-01T00:00:00Z /library/oar/handle/123456789/18514 Title: Dynamic cluster scheduling for ALICE Abstract: With the ever-increasing growth in data processing, simulation and other computation-heavy operations, more organisations are resorting to the use of computer clusters in order to keep up with their computational demands. A Large Ion Collider Experiment (ALICE), one of the experiments at the European Organisation for Nuclear Research (CERN), clearly exemplifies this demand for computational power, with hundreds of computing centres devoted to process and analyse petabytes of data generated yearly by the Large Hadron Collider (LHC). A number of problem domains often employ the use of specialised distributed software frameworks which assume total control of cluster resources, making efficient resource utilisation difficult when running the frameworks concurrently. In this work, meta-scheduling approaches are investigated in order to mitigate the resource allocation problem present when running multiple frameworks concurrently; in par- ticular, Apache Mesos, a meta-scheduler for distributed systems, is employed and extended to improve resource allocation without resorting to static partitioning. Furthermore, this research investigates the use of network topology-aware scheduling for a number of application profiles; a novel method for automatic dynamic network topology discovery using Layer 2 devices is presented and evaluated. The results show that employing topology-aware meta-scheduling strategies can drastically improve performance for certain application profiles, demonstrating significant speed-up, while also improving resource utilisation. Description: M.SC.COMPUTER SCIENCE 2016-01-01T00:00:00Z