1,722,524 research outputs found
Human-powered inertial energy harvesters: the effect of orientation, location and activity on the obtainable electrical power
No full textHuman-powered inertial energy harvesting is an emerging technology that can power electronic devices using electrical energy scavenged from human motion. Traditional energy harvesters generate energy only from a single axis, and are referred to one degree-of-freedom (1-DOF) energy harvesters. In this thesis, a two degree-of-freedom (2-DOF) energy harvester consisting of two orthogonal 1-DOF energy harvesters is studied. This research theoretically and experimentally investigates the effect of orientation, location and activity on the obtainable power from 2-DOF human-powered inertial energy harvesters.An on-body measurement study has been conducted to collect acceleration data from five key locations on the body during both walking and running. The collected data have been analyzed to evaluate the harvestable power along different orientations of both 1-DOF and 2-DOF inertial energy harvesters. The results show that the orientation of 1-DOF generators on the body greatly affects the output power. 2-DOF generators can maintain a more constant power output with rotation, thus are more reliable than 1-DOF generators. For 1-DOF generators, and for each location and activity, only 6% of the tested orientations harvest over 90% of the maximum power. For 2-DOF generators, this is increased to 32%, showing a considerable improvement.To validate the analytical results, 1-DOF mechanical- and magnetic-spring electromagnetic generators have been designed and prototyped. A novel design has been proposed to linearise magnetic springs for low frequency use. Experimental validation shows that the design exhibits a linearity of 2% across a ±25 mm displacement range, presenting a significant improvement over the state-of-the-art. A 2-DOF inertial generator that consists of two orthogonal 1-DOF mechanical-spring generators has been tested at three locations around the knee while running. At each location, the 2-DOF generator has been rotated to four different angles. The results show that 2-DOF generators can generate over 81% of the maximum power in all orientations. For 1-DOF generators, it is only 35%
Point Pattern Synthesis via Irregular Convolution
No full textPoint pattern synthesis is a fundamental tool with various applications in computer graphics. To synthesize a point pattern, some techniques have taken an example-based approach, where the user provides a small exemplar of the target pattern. However, it remains challenging to synthesize patterns that faithfully capture the structures in the given exemplar. In this paper, we present a new example-based point pattern synthesis method that preserves both local and non-local structures present in the exemplar. Our method leverages recent neural texture synthesis techniques that have proven effective in synthesizing structured textures. The network that we present is end-to-end. It utilizes an irregular convolution layer, which converts a point pattern into a gridded feature map, to directly optimize point coordinates. The synthesis is then performed by matching inter- and intra-correlations of the responses produced by subsequent convolution layers. We demonstrate that our point pattern synthesis qualitatively outperforms state-of-the-art methods on challenging structured patterns, and enables various graphical applications, such as object placement in natural scenes, creative element patterns or realistic urban layouts in a 3D virtual environment.Computer Graphics ForumSynthesis and Learning38
The Prevalence of Large and Small Colony-types of Malassezia pachydermatis in Normal Canine Ears
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