Effects of two teaching methods of connected speech in a Polish EFL classroom

The results demonstrate that in general, NF proved more effective than NNF. With regard to individual processes of connected speech, NF was more effective in production, whereas no such effect was found for perception

Theory Based on Device Current Clipping to Explain and Predict Performance Including Distortion of Power Amplifiers for Wireless Communication Systems

Power amplifiers are critical components in wireless communication systems that need to have high efficiency, in order to conserve battery life and minimise heat generation, and at the same time low distortion, in order to prevent increase of bit error rate due to constellation errors and adjacent channel interference. This thesis is aimed at meeting a need for greater understanding of distortion generated by power amplifiers of any technology, in order to help designers manage better the trade-off between obtaining high efficiency and low distortion. The theory proposed in this thesis to explain and predict the performance of power amplifiers, including distortion, is based on analysis of clipping of the power amplifier device current, and it is a major extension of previous clipping analyses, that introduces many key definitions and concepts. Distortion and other power amplifier metrics are determined in the form of 3-D surfaces that are plotted against PA class, which is determined by bias voltage, and input signal power level. It is shown that the surface of distortion exhibits very high levels due to clipping in the region where efficiency is high. This area of high distortion is intersected by a valley that is ‘L’-shaped. The 'L'-shaped valley is subject to a rotation that depends on the softness of the cut-off of the power amplifier device transfer characteristic. The distortion surface with rotated 'L'-shaped valley leads to predicted curves for distortion versus input signal power that match published measured curves for power amplifiers even using very simple device models. The distortion versus input signal power curves have types that are independent of technology. In class C, there is a single deep null. In the class AB range, that is divided into three sub-ranges, there may be two deep nulls (sub-range AB(B)), a ledge (sub-range AB(A)) or a shallow null with varying depth (sub-range AB(AB))

A novel parallel algorithm for surface editing and its FPGA implementation

A thesis submitted to the University of Bedfordshire in partial fulfilment of the requirements for the degree of Doctor of PhilosophySurface modelling and editing is one of important subjects in computer graphics. Decades of research in computer graphics has been carried out on both low-level, hardware-related algorithms and high-level, abstract software. Success of computer graphics has been seen in many application areas, such as multimedia, visualisation, virtual reality and the Internet. However, the hardware realisation of OpenGL architecture based on FPGA (field programmable gate array) is beyond the scope of most of computer graphics researches. It is an uncultivated research area where the OpenGL pipeline, from hardware through the whole embedded system (ES) up to applications, is implemented in an FPGA chip. This research proposes a hybrid approach to investigating both software and hardware methods. It aims at bridging the gap between methods of software and hardware, and enhancing the overall performance for computer graphics. It consists of four parts, the construction of an FPGA-based ES, Mesa-OpenGL implementation for FPGA-based ESs, parallel processing, and a novel algorithm for surface modelling and editing. The FPGA-based ES is built up. In addition to the Nios II soft processor and DDR SDRAM memory, it consists of the LCD display device, frame buffers, video pipeline, and algorithm-specified module to support the graphics processing. Since there is no implementation of OpenGL ES available for FPGA-based ESs, a specific OpenGL implementation based on Mesa is carried out. Because of the limited FPGA resources, the implementation adopts the fixed-point arithmetic, which can offer faster computing and lower storage than the floating point arithmetic, and the accuracy satisfying the needs of 3D rendering. Moreover, the implementation includes Bézier-spline curve and surface algorithms to support surface modelling and editing. The pipelined parallelism and co-processors are used to accelerate graphics processing in this research. These two parallelism methods extend the traditional computation parallelism in fine-grained parallel tasks in the FPGA-base ESs. The novel algorithm for surface modelling and editing, called Progressive and Mixing Algorithm (PAMA), is proposed and implemented on FPGA-based ES’s. Compared with two main surface editing methods, subdivision and deformation, the PAMA can eliminate the large storage requirement and computing cost of intermediated processes. With four independent shape parameters, the PAMA can be used to model and edit freely the shape of an open or closed surface that keeps globally the zero-order geometric continuity. The PAMA can be applied independently not only FPGA-based ESs but also other platforms. With the parallel processing, small size, and low costs of computing, storage and power, the FPGA-based ES provides an effective hybrid solution to surface modelling and editing

Special Libraries, April 1932

Volume 23, Issue 4https://scholarworks.sjsu.edu/sla_sl_1932/1003/thumbnail.jp

Molecular gas in NUclei of GAlaxies (NUGA). XI. A complete gravity torque map of NGC4579: new clues on bar evolution

We create a complete gravity torque map of the disk of the LINER/Seyfert 1.9 galaxy NGC4579. We quantify the efficiency of angular momentum transport and search for signatures of secular evolution in the fueling process from r~15kpc down to the inner r~50pc around the Active Galactic Nucleus (AGN). We use both the 1-0 and 2-1 line maps of CO obtained with the Plateau de Bure Interferometer (PdBI) as part of the NUclei of Galaxies-(NUGA)-project. We derive the stellar potential from a NIR (K band) wide field image of the galaxy. The K-band image, which reveals a stellar bar, together with a high resolution HI map of NGC4579 obtained with the Very Large Array (VLA), allow us to extend the gravity torque analysis to the outer disk. The bulk of the gas response traced by the CO PdBI maps follows the expected gas flow pattern induced by the bar potential in the presence of two Inner Lindblad Resonances (ILR). We also detect an oval distortion in the inner r~200pc of the K-band image. The oval is not aligned with the large-scale bar, a signature of dynamical decoupling. The morphology of the outer disk suggests that the neutral gas is currently piling up in a pseudo-ring formed by two winding spiral arms that are morphologically decoupled from the bar structure. In the outer disk, the decoupling of the spiral allows the gas to efficiently produce net gas inflow on intermediate scales. The corotation barrier seems to be overcome due to secular evolution processes. The gas in the inner disk is efficiently funneled by gravity torques down to r~300pc. Closer to the AGN, the two m=2 modes (bar and oval) act in concert to produce net gas inflow down to r~50pc, providing a clear smoking gun evidence of fueling with associated short dynamical time-scales.Comment: Submitted for publication in A&A. 21 pages, 21 figure

Notes in improvisation : Spatializing Black Identity through music

The self-creation of Black spaces in America has been a form of resistance and reclamation, as well as a way to forge an identity and make room for community. This thesis argues for a use of improvisational African American music as a tool to create space. Additionally, through research and a design intervention, this thesis seeks to demonstrate how spatial creation within the framework of music and musical improvisation work as ways to expand, solidify and celebrate identity within Black and African- identifying people in America. Fluid and improvisational techniques found in Black musical styles and genres such as jazz set the foundation for this thesis, which readapts into a contemporary setting the site of a historic jazz bar in West Philadelphia, Pennsylvania formerly called the Aqua Lounge. Restoration and adaptation are employed as intervention strategies within the site, which is currently used as a retail shop called the African Cultural Art Forum (ACAF). Portions of the site’s cultural heritage will survive as it programmatically becomes a space informed by and for music, with improvisation employed as a design strategy to create flexible architectural frameworks. The design intervention uses overlapping programs to create spaces that create a dialogue within the interior of the building and also between the interior and exterior of the site. Doors are rehinged to also work as seating, new floors are inserted within the building to create “micro floors” for recording studios and the existing first, second and third floors become retail, archival and performance spaces that harken back to programs that have existed within this site over time. Reworking functions of architectural programs and existing materials creates an adaptable space open to new interpretation to the future users. Noise, sound and rhythm inspire fluid and less rigid architecture, creating spaces that support the people and communities who contribute to Black cultural expression. Philadelphia is known as “The City of Murals” and in support of themes within this thesis the site will benefit from keeping its existing mural intact on the site. The Aqua Lounge jazz bar is considered the foundational palimpsest layer, and the expression of jazz as improvisational leads to new forms of unplanned expressions within the site. Through an architectural design the aim is to loosely design these programs in a way that can be re-written by future users of this site

Interactive isosurface ray tracing of time-varying tetrahedral volumes

Journal ArticleAbstract- We describe a system for interactively rendering isosurfaces of tetrahedral finite-element scalar fields using coherent ray tracing techniques on the CPU. By employing state-of-the art methods in polygonal ray tracing, namely aggressive packet/frustum traversal of a bounding volume hierarchy, we can accomodate large and time-varying unstructured data. In conjunction with this efficiency structure, we introduce a novel technique for intersecting ray packets with tetrahedral primitives. Ray tracing is flexible, allowing for dynamic changes in isovalue and time step, visualization of multiple isosurfaces, shadows, and depth-peeling transparency effects. The resulting system offers the intuitive simplicity of isosurfacing, guaranteed-correct visual results, and ultimately a scalable, dynamic and consistently interactive solution for visualizing unstructured volumes

Probing the Outer Mouth Structure of the hERG Channel with Peptide Toxin Footprinting and Molecular Modeling

Abstract Previous studies have shown that the unusually long S5-P linker lining human ether a-go-go related gene’s (hERG’s) outer vestibule is critical for its channel function: point mutations at high-impact positions here can interfere with the inactivation process and, in many cases, also reduce the pore’s K+ selectivity. Because no data are available on the equivalent region in the available K channel crystal structures to allow for homology modeling, we used alternative approaches to model its three-dimensional structure. The first part of this article describes mutant cycle analysis used to identify residues on hERG’s outer vestibule that interact with specific residues on the interaction surface of BeKm-1, a peptide toxin with known NMR structure and a high binding affinity to hERG. The second part describes molecular modeling of hERG’s pore domain. The transmembrane region was modeled after the crystal structure of KvAP pore domain. The S5-P linker was docked to the transmembrane region based on data from previous NMR and mutagenesis experiments, as well as a set of modeling criteria. The models were further restrained by contact points between hERG’s outer vestibule and the bound BeKm-1 toxin molecule deduced from the mutant cycle analysis. Based on these analyses, we propose a working model for the open conformation of the outer vestibule of the hERG channel, in which the S5-P linkers interact with the pore loops to influence ion flux through the pore

Development of fibre and particulate filled aerogel composites for subsea pipeline applications

Error on title page – year of award is 2021.The aim of this project is to develop an analytical tool through Finite Element Method to understand and guide the design of thermal insulation materials. In particular, fibrous mat and aerogel particle-filled resin are focused in the context of subsea pipe-in-pipe (PiP) application for oil and gas extraction. The former has become part of a novel combination with super-insulating material – aerogel, and found its commercial use in the annulus region of the PiP. The latter is considered to be a form of upgrade to the current nylon-based centraliser stabilising the PiP configuration under hydraulic pressure from the deep seawater. The use of porous materials (e.g. fibrous matt and foam) as thermal insulation has a long history, A randomly orientated fibre mat is effective insulation due to the lack of a straight heat conduction pathway and relatively small pores in the fibrous structure. Recent development of super insulating materials involves combining fibrous mat with aerogel, which has resulted in a flexible and less compressible aerogel-fibre blanket with lower thermal conductivity (14 – 20 mw/mK) than typical conventional fibrous counterparts (35 – 50 mw/mK). However, a fundamental understanding of how the fibrous mat interacts the aerogel has not been extensively studied. The use of porous particle-filled resin composites, particularly with aerogel particles, has received less studies in thermal cases and a similar understanding of such integration must be developed in order to inform the design process. The rationale for carrying out this research was to create a range of simulations that can be easily used to predict the effect of changing properties of these above composites on their thermal and mechanical performance. The use of simulations is less time consuming and allows more parameters to be easily varied to see what the optimal fibre design is for specific applications. In order to simulate the effects of varying the composition of the mats, an algorithm to generate a random fibre mat was produced, based on the work of Arambakam and Tafreshi [1]. This fibre positioning was done in MathWorks’ MATLAB, which was used to generate a script for producing a 3D geometry that can be incorporated in ANSYS APDL. This geometry was then used as the basis for a 3D finite element method model that utilised ANSYS Mechanical to mesh and solve the simulation. The same fibre generation process was used for both the mechanical and the thermal simulations, but with the bounding region being differently shaped to accommodate representing the standard experimental techniques used to measure these values. Simulations were carried out to investigate the effect of various parameters of the fibre mat. Specifically, the fibre orientation and the volume fraction of the mat were the main parameters of importance, with the orientation both in and out of the plane of heat transfer being investigated. The ratio of straight fibres to sinusoidal fibres was also investigated as a key parameter affecting the heat transfer, with the volume of straight fibres to total fibre volume being used to determine the “straight fibre fraction” of the fibres. The effect of the fibre length and diameter were also investigated, though it was found that on the scales investigated, they had very little effect on the thermal conductivity. A study into using fully random fibres, where the fibre can be represented by a continuous curve in 3D space that varies in direction throughout the length, was carried out. However, the high level of complexity of this fibre configuration along with the large number of fibre intersections meant that meshing the geometry produced was very difficult. Some successful meshes were produced; however, they included a number of elements that was too large to successfully produce a solution using finite element analysis. For aerogel particle-filled resin, an effort was made to investigate the effect of dispersing particles of aerogel through a resin matrix, in an effort to reduce the thermal conductivity of the matrix. The results of this showed that it was theoretically possible to achieve significantly lower thermal conductivity. The material properties generated from the FE simulations were then used in modelling the centraliser to determine the insulations effectiveness in pipe in pipe insulation. These simulations included the particle simulation data to guide the addition of aerogel particles in the resin matrix to further reduce the conductivity. The work carried out in this project created an alternative approach to generating and manipulating geometry (shape and size distribution) and spatial position within a representative volume element (RVE) of composites. This has enabled a micro-scale modelling for obtaining such properties as thermal conductivity and modulus of the fibrous matt in itself as well as the particle-filled resin composites. An excellent agreement was found between the modelling results and experimental data.The aim of this project is to develop an analytical tool through Finite Element Method to understand and guide the design of thermal insulation materials. In particular, fibrous mat and aerogel particle-filled resin are focused in the context of subsea pipe-in-pipe (PiP) application for oil and gas extraction. The former has become part of a novel combination with super-insulating material – aerogel, and found its commercial use in the annulus region of the PiP. The latter is considered to be a form of upgrade to the current nylon-based centraliser stabilising the PiP configuration under hydraulic pressure from the deep seawater. The use of porous materials (e.g. fibrous matt and foam) as thermal insulation has a long history, A randomly orientated fibre mat is effective insulation due to the lack of a straight heat conduction pathway and relatively small pores in the fibrous structure. Recent development of super insulating materials involves combining fibrous mat with aerogel, which has resulted in a flexible and less compressible aerogel-fibre blanket with lower thermal conductivity (14 – 20 mw/mK) than typical conventional fibrous counterparts (35 – 50 mw/mK). However, a fundamental understanding of how the fibrous mat interacts the aerogel has not been extensively studied. The use of porous particle-filled resin composites, particularly with aerogel particles, has received less studies in thermal cases and a similar understanding of such integration must be developed in order to inform the design process. The rationale for carrying out this research was to create a range of simulations that can be easily used to predict the effect of changing properties of these above composites on their thermal and mechanical performance. The use of simulations is less time consuming and allows more parameters to be easily varied to see what the optimal fibre design is for specific applications. In order to simulate the effects of varying the composition of the mats, an algorithm to generate a random fibre mat was produced, based on the work of Arambakam and Tafreshi [1]. This fibre positioning was done in MathWorks’ MATLAB, which was used to generate a script for producing a 3D geometry that can be incorporated in ANSYS APDL. This geometry was then used as the basis for a 3D finite element method model that utilised ANSYS Mechanical to mesh and solve the simulation. The same fibre generation process was used for both the mechanical and the thermal simulations, but with the bounding region being differently shaped to accommodate representing the standard experimental techniques used to measure these values. Simulations were carried out to investigate the effect of various parameters of the fibre mat. Specifically, the fibre orientation and the volume fraction of the mat were the main parameters of importance, with the orientation both in and out of the plane of heat transfer being investigated. The ratio of straight fibres to sinusoidal fibres was also investigated as a key parameter affecting the heat transfer, with the volume of straight fibres to total fibre volume being used to determine the “straight fibre fraction” of the fibres. The effect of the fibre length and diameter were also investigated, though it was found that on the scales investigated, they had very little effect on the thermal conductivity. A study into using fully random fibres, where the fibre can be represented by a continuous curve in 3D space that varies in direction throughout the length, was carried out. However, the high level of complexity of this fibre configuration along with the large number of fibre intersections meant that meshing the geometry produced was very difficult. Some successful meshes were produced; however, they included a number of elements that was too large to successfully produce a solution using finite element analysis. For aerogel particle-filled resin, an effort was made to investigate the effect of dispersing particles of aerogel through a resin matrix, in an effort to reduce the thermal conductivity of the matrix. The results of this showed that it was theoretically possible to achieve significantly lower thermal conductivity. The material properties generated from the FE simulations were then used in modelling the centraliser to determine the insulations effectiveness in pipe in pipe insulation. These simulations included the particle simulation data to guide the addition of aerogel particles in the resin matrix to further reduce the conductivity. The work carried out in this project created an alternative approach to generating and manipulating geometry (shape and size distribution) and spatial position within a representative volume element (RVE) of composites. This has enabled a micro-scale modelling for obtaining such properties as thermal conductivity and modulus of the fibrous matt in itself as well as the particle-filled resin composites. An excellent agreement was found between the modelling results and experimental data