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Science and Technology Studies Commons

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2015

Approach

Articles 1 - 10 of 10

Full-Text Articles in Science and Technology Studies

A Combined Experimental-Numerical Approach For Determining Mechanical Properties Of Aluminum Subjects To Nanoindentation, Mao Liu, Cheng Lu, A Kiet Tieu, Ching-Tun Peng, Charlie Kong Jan 2015

A Combined Experimental-Numerical Approach For Determining Mechanical Properties Of Aluminum Subjects To Nanoindentation, Mao Liu, Cheng Lu, A Kiet Tieu, Ching-Tun Peng, Charlie Kong

Faculty of Engineering and Information Sciences - Papers: Part A

A crystal plasticity finite element method (CPFEM) model has been developed to investigate the mechanical properties and micro-texture evolution of single-crystal aluminum induced by a sharp Berkovich indenter. The load-displacement curves, pile-up patterns and lattice rotation angles from simulation are consistent with the experimental results. The pile-up phenomenon and lattice rotation have been discussed based on the theory of crystal plasticity. In addition, a polycrystal tensile CPFEM model has been established to explore the relationship between indentation hardness and yield stress. The elastic constraint factor C is slightly larger than conventional value 3 due to the strain hardening.


Multizone Reproduction Of Speech Soundfields: A Perceptually Weighted Approach, Jacob Donley, Christian H. Ritz Jan 2015

Multizone Reproduction Of Speech Soundfields: A Perceptually Weighted Approach, Jacob Donley, Christian H. Ritz

Faculty of Engineering and Information Sciences - Papers: Part A

In this paper a method for the reproduction of multizone speech soundfields using perceptual weighting criteria is proposed. Psychoacoustic models are used to derive a space-time-frequency weighting function to control leakage of perceptually unimportant energy from the bright zone into the quiet zone. This is combined with a method for regulating the number of basis planewaves used in the reproduction to allow for an efficient implementation using a codebook of predetermined weights based on desired soundfield energy in the zones. The approach is capable of improving the mean squared error for reproduced speech in the bright zone by -10.5 ...


A Subspace Projection Approach For Wall Clutter Mitigation In Through-The-Wall Radar Imaging, Fok Hing Chi Tivive, Abdesselam Bouzerdoum, Moeness Amin Jan 2015

A Subspace Projection Approach For Wall Clutter Mitigation In Through-The-Wall Radar Imaging, Fok Hing Chi Tivive, Abdesselam Bouzerdoum, Moeness Amin

Faculty of Engineering and Information Sciences - Papers: Part A

One of the main challenges in through-the-wall radar imaging (TWRI) is the strong exterior wall returns, which tend to obscure indoor stationary targets, rendering target detection and classification difficult, if not impossible. In this paper, an effective wall clutter mitigation approach is proposed for TWRI that does not require knowledge of the background scene nor does it rely on accurate modeling and estimation of wall parameters. The proposed approach is based on the relative strength of the exterior wall returns compared to behind-wall targets. It applies singular value decomposition to the data matrix constructed from the space-frequency measurements to identify ...


A New Approach For Classification And Characterization Of Voltage Dips And Swells Using 3d Polarization Ellipse Parameters, Mollah R. Alam, Kashem M. Muttaqi, Abdesselam Bouzerdoum Jan 2015

A New Approach For Classification And Characterization Of Voltage Dips And Swells Using 3d Polarization Ellipse Parameters, Mollah R. Alam, Kashem M. Muttaqi, Abdesselam Bouzerdoum

Faculty of Engineering and Information Sciences - Papers: Part A

This paper presents a new method for classification and characterization of voltage dips and swells in electricity networks. The proposed method exploits unique signatures and parameters of three phase voltage signals extracted from the polarization ellipse in three-dimensional (3D) co-ordinates. Five ellipse parameters, which include azimuthal angle, elevation, tilt, semi-minor axis and semi-major axis, are used to classify and characterize voltage dips and swells. Seven types of voltage dips, which include a total of 19 groups of dips incorporating different kinds of balanced (three-phase dips) and unbalanced (single-phase or double-phase) dips, are identified and successfully classified using the 3D polarization ...


An Efficient Background Modeling Approach Based On Vehicle Detection, Jia-Yan Wang, Limei Song, Jiangtao Xi, Qinghua Guo Jan 2015

An Efficient Background Modeling Approach Based On Vehicle Detection, Jia-Yan Wang, Limei Song, Jiangtao Xi, Qinghua Guo

Faculty of Engineering and Information Sciences - Papers: Part A

The existing Gaussian Mixture Model(GMM) which is widely used in vehicle detection suffers inefficiency in detecting foreground image during the model phase, because it needs quite a long time to blend the shadows in the background. In order to overcome this problem, an improved method is proposed in this paper. First of all, each frame is divided into several areas(A, B, C and D), Where area A, B, C and D are decided by the frequency and the scale of the vehicle access. For each area, different new learning rate including weight, mean and variance is applied to ...


An Efficient Approach To Dynamically Weighted Multizone Wideband Reproduction Of Speech Soundfields, Jacob Donley, Christian H. Ritz Jan 2015

An Efficient Approach To Dynamically Weighted Multizone Wideband Reproduction Of Speech Soundfields, Jacob Donley, Christian H. Ritz

Faculty of Engineering and Information Sciences - Papers: Part A

This paper proposes and evaluates an efficient approach for practical reproduction of multizone soundfields for speech sources. The reproduction method, based on a previously proposed approach, utilises weighting parameters to control the soundfield reproduced in each zone whilst minimising the number of loudspeakers required. Proposed here is an interpolation scheme for predicting the weighting parameter values of the multizone soundfield model that otherwise requires significant computational effort. It is shown that initial computation time can be reduced by a factor of 1024 with only 85dB of error in the reproduced soundfield relative to reproduction without interpolated weighting parameters. The perceptual ...


Multi-Phase Variety Trials Using Both Composite And Individual Replicate Samples: A Model-Based Design Approach, Alison B. Smith, David G. Butler, C R. Cavanagh, Brian R. Cullis Jan 2015

Multi-Phase Variety Trials Using Both Composite And Individual Replicate Samples: A Model-Based Design Approach, Alison B. Smith, David G. Butler, C R. Cavanagh, Brian R. Cullis

Faculty of Engineering and Information Sciences - Papers: Part A

The present paper provides an approach for the design and analysis of variety trials that are used to obtain quality trait data. These trials are multi-phase in nature, comprising a field phase followed by one or more laboratory phases. Typically the laboratory phases are costly relative to the field phase and this imposes a limit on the number of samples that can be tested. Historically, this has been achieved by sacrificing field replication, either by testing a single replicate plot for each variety or a single composite sample, obtained by combining material from several field replicates. An efficient statistical analysis ...


Indirect Radio-Chemo-Beta Therapy: A Targeted Approach To Increase Biological Efficiency Of X-Rays Based On Energy, Sianne Oktaria, Stephanie Corde, Michael L. F Lerch, Konstantin K. Konstantinov, Anatoly B. Rosenfeld, Moeava Tehei Jan 2015

Indirect Radio-Chemo-Beta Therapy: A Targeted Approach To Increase Biological Efficiency Of X-Rays Based On Energy, Sianne Oktaria, Stephanie Corde, Michael L. F Lerch, Konstantin K. Konstantinov, Anatoly B. Rosenfeld, Moeava Tehei

Faculty of Engineering and Information Sciences - Papers: Part A

Despite the use of multimodal treatments incorporating surgery, chemotherapy and radiotherapy, local control of gliomas remains a major challenge. The potential of a new treatment approach called indirect radio-chemo-beta therapy using the synergy created by combining methotrexate (MTX) with bromodeoxyuridine (BrUdR) under optimum energy x-ray irradiation is assessed. 9L rat gliosarcoma cells pre-treated with 0.01 μM MTX and/or 10 μM BrUdR were irradiated in vitro with 50 kVp, 125 kVp, 250 kVp, 6 MV and 10 MV x-rays. The cytotoxicity was assessed using clonogenic survival as the radiobiological endpoint. The photon energy with maximum effect was determined using ...


A New Approach To Reduce The Expected Energy Not Supplied In A Power Plant Located In A Non-Expandable Transmission System, Hadi Lomei, Danny Sutanto, Kashem M. Muttaqi, Mohsen Assili Jan 2015

A New Approach To Reduce The Expected Energy Not Supplied In A Power Plant Located In A Non-Expandable Transmission System, Hadi Lomei, Danny Sutanto, Kashem M. Muttaqi, Mohsen Assili

Faculty of Engineering and Information Sciences - Papers: Part A

The main objective of most of power plants is to inject power as much as possible into the grid from the power plants. However, the transmission system may restrain the output capability of the power plant, especially, if the power plant is located in an area of non-expandable transmission system. In this situation, any disturbance in the nearby transmission system may force the plant to generate lower than its rated value, which disables it from selling the remaining available generated power to the costumers and also increases the cost of energy not supplied. In this paper, an efficient method is ...


A New Approach To Reduce The Non-Linear Characteristics Of A Stressed Power System By Using The Normal Form Technique In The Control Design Of The Excitation System, Hadi Lomei, Danny Sutanto, Kashem M. Muttaqi, Mohsen Assili Jan 2015

A New Approach To Reduce The Non-Linear Characteristics Of A Stressed Power System By Using The Normal Form Technique In The Control Design Of The Excitation System, Hadi Lomei, Danny Sutanto, Kashem M. Muttaqi, Mohsen Assili

Faculty of Engineering and Information Sciences - Papers: Part A

In this paper, a new approach is presented to reduce the nonlinear characteristics of a stressed power system by reducing its second-order modal interaction through retuning some parameters of the generator excitation system. In order to determine the second-order modal interaction of the system, a new index on nonlinearity is developed using normal form theory. Using the proposed index of nonlinearity, a sensitivity function is formed to indicate the most effective excitation system parameters in the nonlinear behavior of the system. These dominant parameters are tuned to reduce the second-order modal interaction of the system and to reduce the index ...