Diffusion-weighted magnetic resonance imaging can be used to estimate microstructural parameters of white matter in the brain. Two complementary techniques are investigated: the use of the temporal diffusion spectrum to explore small length scales and the STEAM technique to probe larger features. The diffusion spectrum has the potential to be more sensitive to small pores compared to conventional time-dependent diffusion. However, analytical expressions for the diffusion spectrum of particles only exist for simple geometries such as cylinders, which are often used as a model for intra-axonal diffusion. We propose a mathematical model for the extra-axonal space with parameters that are related to the microstructural properties of pore size, tortuosity, and surface-to-volume ratio. Measurements were made with an extra-axonal space phantom to validate the model. Fitted values for the phantom pore size match those from simulation. We extend the model to include the intra-axonal signal contribution. However, the parameters used to describe the intra- and extra-axonal spaces are related and it is important to remove redundant parameters to avoid overparameterization, which would make the model less robust. We propose analytical expressions to simplify the model. The model was then applied to measurements on fixed corpus callosum, which is a model system consisting of parallel axons. The estimated values of the axon volume fraction and mean and standard deviation of the axon radius distribution are comparable to those found in literature. Temporal diffusion spectra are useful for measuring the geometric properties of small spaces such as axon radii. However, longer diffusion times accessible using the STEAM sequence are necessary to probe structures with longer diffusion distances such as those parallel to the direction of axons. We used a model from the literature originally developed for use with animal magnetic resonance scanners and simplified it to quantify axial hindrance from data acquired on healthy volunteers in a clinical scanner. The interpretation of axial hindrance, which is a largely unexplored area of research, is discussed.

Space organisation of urban blocks is a significant topic of urban design field to achieve correlated urban parts that enhance the variety in urban spaces. However, the rapid urban transformation experienced in the Turkish cities resulted in the generation of similar urban blocks with the lack of spatial variety. Therefore, a re-evolution of space organisation concepts for urban blocks emerges as a design problem in order to cope with the defined problem. From this point of view, the interfaces among public, common and private spaces as the formative parts of space organisation process constitute the essence of this study. Thus, the morphological elements of urban blocks as street, plot and building are constantly reshaped and redefined based on the correlations of this realms. Within this scope, Conzen&rsquo / s town plan method has been adopted in this study for Bah&ccedil / elievler Housing Cooperative Site, to reveal the transformation experienced and the changing relations of street, plot and building throughout the morphological formation processes. In the light of this problem case and method implemented, this research indicates that in Bah&ccedil / elievler, the changing relations between street, plot and buildings are an outcome of the interfaces among public, common and private regarding the permeability along boundaries. Based on this outcome, this study suggests that a new understanding of space organisation in urban blocks regarding the interfaces among public, common and private spaces as counterparts of street, plot and buildings arises as a significant issue that needs to be reconsidered by urban designers, planners, architects and public authorities while defining the design and planning process.

This study is an exploration of the integration in composition of theoretical and psychoacoustic properties of pitch and duration; its aims are essentially practical in showing how cognitive research can inform composition, but it also addresses more broadly the value and role cognition can have in the current musical compositional climate. Various contexts for this exploration are discussed: the mediating role analysis has within theory and composition; constraints imposed by aesthetic positions and music theory/pedagogy templates; the role of cognitive psychology in connecting music templates and listening experiences; and the ultimately mythopoetic (Cook, 1992) rather than scientific nature of any such theory/psychology integration. Using Huovinen’s “pitch constellation” approach and Lerdahl’s theory of tonal pitch space, a hierarchical pitch-space is set up for the string piece ed erra l’armonia, developing from pc set 5-22 a non-standard octatonic scale (pc set 8-27) as the basic pitch collection of the piece. Similarly, using the works of Fraisse, Hasty and London, a hierarchical rhythm-space is set up for the orchestral piece Pneuma developing, from the indifference interval in duration, the temporal and metric envelops and the duple and triple subdivisions of the tactus, a three layered metrical structure as the generative rhythmic template of the piece. This is contextualised against the problematic notion of metre in modern art-music. General characteristic of both spaces are discussed: redundancy according to information theory, hierarchy in relation to cognitive opaqueness, salience and association; and elaborational and permutational processes. It is argued that composition needs to bridge, in practice, the gap between music theory and psychology of music, looking beyond their often absolutist positions; that cognitive constrains in music should be seen as opportunities to work compositionally along the mind’s cognitive grains in order to maximise structural and expressive communication; and that at a time of a ‘deregulated’ musical language it is necessary to re-develop cognitive heuristics to secure the connection between compositional choices and listening experiences. Three principles are given as guidelines for the alignment of theoretical and cognitive issues in composition. It is proposed that cognitive analysis should be developed as an independent discipline as well as a compositional tool, and that the connections style/cognition should be looked at more closely to gain a more unified perspective on diverse (and divisive) stylistic musical camps.

Developing behaviours for interaction with objects close to the body is a primary goal for any organism to survive in the world. Being able to develop such behaviours will be an essential feature in autonomous humanoid robots in order to improve their integration into human environments. Adaptable spatial abilities will make robots safer and improve their social skills, human-robot and robot-robot collaboration abilities. This work investigated how a humanoid robot can explore and create action-based representations of its peripersonal space, the region immediately surrounding the body where reaching is possible without location displacement. It presents three empirical studies based on peripersonal space findings from psychology, neuroscience and robotics. The experiments used a visual perception system based on active-vision and biologically inspired neural networks. The first study investigated the contribution of binocular vision in a reaching task. Results indicated the signal from vergence is a useful embodied depth estimation cue in the peripersonal space in humanoid robots. The second study explored the influence of morphology and postural experience on confidence levels in reaching assessment. Results showed that a decrease of confidence when assessing targets located farther from the body, possibly in accordance to errors in depth estimation from vergence for longer distances. Additionally, it was found that a proprioceptive arm-length signal extends the robot’s peripersonal space. The last experiment modelled development of the reaching skill by implementing motor synergies that progressively unlock degrees of freedom in the arm. The model was advantageous when compared to one that included no developmental stages. The contribution to knowledge of this work is extending the research on biologically-inspired methods for building robots, presenting new ways to further investigate the robotic properties involved in the dynamical adaptation to body and sensing characteristics, vision-based action, morphology and confidence levels in reaching assessment.

The main purpose of this thesis is to calculate the integral cohomology ring of the symmetric square of quaternionic projective space, which has been an open problem since computations with symmetric squares were first proposed in the 1930's. The geometry of this particular case forms an essential part of the thesis, and unexpected results concerning two universal Pin(4) bundles are also included. The cohomological computations involve a commutative ladder of long exact sequences, which arise by decomposing the symmetric square and the corresponding Borel space in compatible ways. The geometry and the cohomology of the configuration space of unordered pairs of distinct points in quaternionic projective space, and of the Thom space MPin(4), also feature, and seem to be of independent interest.

Helping to abstract a valid model from real system, conceptual modeling is an essential phase in simulation development lifecycle. With the development of the KAMA framework, a new methodology was presented to develop mission space conceptual model for simulation systems. It provides metamodel elements represented by graphical diagrams to develop conceptual models of mission space. BOM (Base Object Model), developed by SISO (Simulation Interoperability Standards Organization), is another conceptual modeling concept serving for simulation space. KAMA models are very close to problem domain and intend to model real world concepts in requirement analysis and development phase. Whereas, being vital inputs for the simulation design phase, BOM models are closer to solution domain. Hence there is no defined way of using the captured mission space knowledge in simulation space, problem arises when moving from requirement analysis to design phase. In this study, to solve this problem, we propose a method for transforming mission space conceptual models in simulation space. Our solution approach will be mapping the KAMA mission space models to BOM simulation space models for automatically transport real world analysis results to simulation designers.

This thesis investigates space through its relationship with society based on the idea of the social production of space. By employing the social concepts of community and institution, and the spatial concepts of shelter space and marker space, it provides a theoretical perspective for the evaluation of space in architectural history. This theoretical frame is supplied with a case study on the evolution of Early Christian community and their meeting place. The historical course of the Early Christianity in the Roman Empire from community formation to become an institution &ndash / Christendom - constitutes the paradigm for the social premise of the thesis. On the other hand, the proposed outline for the spatial evolution is demonstrated on the house-church at Dura-Europos.

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This study is an inquiry into the architectural aspects of stage space, which is believed to be the materialization of visual relationships, with the claim that it is also the best illustration of the proposition that architectural discourse is affected by the changes in visual culture. The study is based on the assumption that changes in the conceptualization of architectural space have also been influenced from the shifts in the field of vision, which are the consequences of the changes in the social, political and economical circumstances as well as the developments in science and technology. Within the acknowledgement of three major shifts in the field of vision that have been identified by Jonathan Crary, the study focuses on a reading and assessment of twentieth century developments that differ from the traditional conception of space and ways of spatial representation. Being a key to reconsider architectural space production, the outcomes of these developments are read through the construction of stage and performance spaces. Stage space possesses knowledge about the making of architecture. This study is an attempt to demonstrate how stage space is in relation to or anticipates changes in conception of architecture. Because of its instant nature and flexibility, stage space can be seen as a tool for making experiments for possible changes in the conception of architectural space.

Thesis (M.A.)--University of North Texas, Dec., 2007. / Title from title page display. Includes bibliographical references.