• Journal of Computing Science and Engineering
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• v.8 no.3
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• pp.129-136
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• 2014

This paper presents the equivalent circuit modelling and eigenfrequency analysis of a wideband robust capacitive radio frequency (RF) microelectromechanical system (MEMS) switch that was designed using Poly-Si and Au layer membrane for highly reliable switching operation. The circuit characterization includes the extraction of resistance, inductance, on and off state capacitance, and Q-factor. The first six eigenfrequencies are analyzed using a finite element modeler, and the equivalent modes are demonstrated. The switch is optimized for millimeter wave frequencies, which indicate excellent RF performance with isolation of more than 55 dB and a low insertion loss of 0.1 dB in the V-band. The designed switch actuates at 13.2 V. The R, L, C and Q-factor are simulated using Y-matrix data over a frequency sweep of 20-100 GHz. The proposed switch has various applications in satellite communication networks and can also be used for devices that will incorporate the upcoming IEEE Wi-Fi 802.11ad protocol.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.9
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• pp.56-62
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• 2022

This study analyzed the output precision of 3D printing methods. The inner impeller of the centrifugal compressor was printed in as a sheet with 100% packing density using two methods: field deposition modelling and stereolithography. Dimensional differences between the initial CAD and printed models were evaluated using a 3D scanner. To investigate the dimensional characteristics of the 3D printed impeller, 3D dimension analysis and point dimension analysis were performed. The point dimension analysis was divided into 3D and 2D for comparative analysis.

• Journal of electromagnetic engineering and science
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• v.16 no.3
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• pp.182-190
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• 2016

The problem of resolution in antenna ground-penetrating radar (GPR) is very important for the investigation and detection of buried targets. We should solve this problem with software or a numeric method. The purposes of this paper are the modelling and simulation resolution of antenna radar GPR using three antennas, arrays (as in the software REFLEXW), the antenna dipole (as in GprMax2D), and a bow-tie antenna (as in the experimental results). The numeric code has been developed for study resolution antennas by scattered electric fields in mode B-scan. Three frequency antennas (500, 800, and 1,000 MHz) have been used in this work. The simulation results were compared with experimental results obtained by Rial and colleagues under the same conditions.

• Wind and Structures
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• v.5 no.2_3_4
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• pp.267-276
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• 2002

Research being undertaken at the University of Auckland has enabled Vortec Energy to improve the performance of the Vortec 7 Diffuser Augmented Wind Turbine. Computational Fluid Dynamic (CFD) modelling of the Vortec 7 was used to ascertain the effectiveness of geometric modifications to the Vortec 7. The CFD work was then developed to look at new geometries, and refinement of these led to greater power augmentation for a given diffuser exit area ratio. Both full scale analysis of the Vortec 7 and a wind tunnel investigation of the development design have been used for comparison with the CFD model.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.2D
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• pp.311-316
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• 2006

Despite geospatial information systems are widely used in many different fields as a powerful tool for spatial analysis and decision-making, their capabilities to handle realistic 3-D urban environment are very limited. The objective of this work is to integrate the recent developments in 3-D modeling and visualization into GIS to enhance its 3-D capabilities. To achieve a photorealistic view, building models are collected from a pair of aerial stereo images. Roof and wall textures are respectively obtained from ortho-rectified aerial image and ground photography. This study is implemented by using ArcGIS as the work platform and ArcObjects and Visual Basic as development tools. Presented in this paper are 3-D geometric modeling and its data structure, texture creation and its association with the geometric model. As the results, photorealistic views of Purdue University campus are created and rendered with ArcScene.

• Journal of Ocean Engineering and Technology
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• v.9 no.2
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• pp.83-88
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• 1995

In this paper, the solid modeller suitable for PC was developed for Top-down 3-D representation and analysis of fixed offshore structures. Also solid modelling and hidden line removal were conducted in order to visualize the offshore structures based on the scan line z-buffer algorithm.

• Wind and Structures
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• v.5 no.2_3_4
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• pp.151-164
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• 2002

Predictions of the pedestrian level wind speeds for the downtown area of Auckland that have been obtained by wind tunnel and computational fluid dynamic (CFD) modelling are presented. The wind tunnel method involves the observation of erosion patterns as the wind speed is progressively increased. The computational solutions are mean flow calculations, which were obtained by using the finite volume code PHOENICS and the $k-{\varepsilon}$ turbulence model. The results for a variety of wind directions are compared, and it is observed that while the patterns are similar there are noticeable differences. A possible explanation for these differences arises because the tunnel prediction technique is sensitivity to gust wind speeds while the CFD method predicts mean wind speeds. It is shown that in many cases the computational model indicates high mean wind speeds near the corner of a building while the erosion patterns are consistent with eddies being shed from the edge of the building and swept downstream.

• Structural Engineering and Mechanics
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• v.72 no.2
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• pp.257-273
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• 2019

In this paper, the mechanical behaviour of functionally graded material beams is studied using the 3D Saint-Venant's theory, in which the section is free to warp in and out of its plane (Poisson's effects and out-of-plane warpings). The material properties of the FGM beam are distributed continuously through the thickness by several distributions, such as power-law distribution, exponential distribution, Mori-Tanaka schema and sigmoid distribution. The proposed method has been applied to study a simply supported FGM beam. The numerical results obtained are compared to other models in the literature, which show a high performance of the 3D exact theory used to describe the stress and strain fields in FGM beams.

• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.214-216
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• 1998

Parameterizing a model is one of the most efficient ways of conducting "virtual prototying" i.e. exploring the "What if?" scenario. But it is very difficult to construct parameterized models in commercial based FEM programs, because they usually adopt the mouse inputs in their GUI, which cannot be parameterized. We consolidated a parametric modelling technique in OPERA-3d preprocessor, which is one of world leading electromagnetic analysis programs, by combining the mouse inputs in GUI with it's FORTRAN-based self script command language.

• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.87.2-87.2
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• 2007