ORCID Profile
0000-0003-4702-4002
Current Organisation
UNSW Canberra
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Publisher: Institution of Engineering and Technology (IET)
Date: 11-2014
DOI: 10.1049/EL.2014.3142
Publisher: Informa UK Limited
Date: 06-01-2015
Publisher: IGI Global
Date: 2017
DOI: 10.4018/978-1-5225-0571-6.CH046
Abstract: Compressed sensing, also known as compressive s ling is a new technique being rapidly developed over the last few years. The theory states that when some prior information about the signal is available and appropriately incorporated into the signal reconstruction procedure, a signal can be accurately reconstructed even if the Shannon/ Nyquest s ling requirement is violated. The key idea of compressed sensing is to recover a sparse signal from very few non-adaptive, linear measurements by optimization technique. Following the discovery by Donoho in (2006), that sparsity could enable exact solution of ill-posed problems under certain conditions, there has been a tremendous growth on efficient application of sparsity constraints for solving ill-posed problems. The theoretical foundation of compressed sensing has already become a key concept in various areas of applied mathematics, computer science, and electrical engineering. In this chapter we will detail the application of compressed sensing in X-ray computed tomography (CT) and Electroencephalography. Starting from the very basic principles we will provide theoretical justifications on why and how sparsity prior is used in CT and in EEG.
Publisher: IEEE
Date: 11-2013
Publisher: No publisher found
Date: 2021
DOI: 10.3390/RS13030455
Publisher: IEEE
Date: 12-2013
Publisher: SPIE
Date: 05-09-2014
DOI: 10.1117/12.2061529
Publisher: SPIE
Date: 13-03-2013
DOI: 10.1117/12.2011073
Publisher: Informa UK Limited
Date: 15-02-2016
Publisher: IEEE
Date: 07-2019
Publisher: Elsevier BV
Date: 08-2013
Publisher: SPIE
Date: 05-08-2015
DOI: 10.1117/12.2191108
Publisher: SPIE
Date: 23-09-2014
DOI: 10.1117/12.2061643
Publisher: The Optical Society
Date: 19-02-2015
DOI: 10.1364/OE.23.005091
Publisher: MDPI AG
Date: 06-2020
DOI: 10.3390/RS12111776
Abstract: Multispectral Polarimetric Imagery (MSPI) contains significant information about an object’s distribution, shape, shading, texture and roughness features which can distinguish between foreground and background in a complex scene. Due to spectral signatures being limited to material properties, Background Segmentation (BS) is a difficult task when there are shadows, illumination and clutter in a scene. In this work, we propose a two-fold BS approach: multiband image fusion and polarimetric BS. Firstly, considering that the background in a scene is polarized by nature, the spectral reflectance and correlations and the textural features of MSPI are calculated and analyzed to demonstrate the fusion significance. After that, integrating Principal Component Analysis (PCA) with Fast Fourier Transform (FFT), a hybrid fusion technique is proposed to show the multiband fusion effectiveness. Secondly, utilizing the Stokes vector, polarimetric components are calculated to separate a complex scene’s background from its foreground by constructing four significant foreground masks. An intensity-invariant mask is built by differentiating between the median filtering versions of unpolarized and polarized images. A strongly unpolarized foreground mask is also constructed in two different ways, through analyzing the Angle of Linear Polarization (AoLP) and Degree of Linear Polarization (DoLP). Moreover, a strongly polarized mask and a strong light intensity mask are also calculated based on the azimuth angle and the total light intensity. Finally, all these masks are combined, and a morphological operation is applied to segment the final background area of a scene. The proposed two-fold BS algorithm is evaluated using distinct statistical measurements and compared with well-known fusion methods and BS methods highlighted in this paper. The experimental results demonstrate that the proposed hybrid fusion method significantly improves multiband fusion quality. Furthermore, the proposed polarimetric BS approach also improves the mean accuracy, geometric mean and F1-score to 0.95, 0.93 and 0.97, respectively, for scenes in the MSPI dataset compared with those obtained from the methods in the literature considered in this paper. Future work will investigate mixed polarized and unpolarized BS in the MSPI dataset with specular reflection.
Publisher: IEEE
Date: 11-2014
Publisher: IEEE
Date: 03-2014
Publisher: The Optical Society
Date: 28-10-2016
DOI: 10.1364/AO.55.008905
Publisher: IEEE
Date: 12-2018
Publisher: IOP Publishing
Date: 19-11-2015
Publisher: IEEE
Date: 11-2021
Publisher: The Optical Society
Date: 23-06-2016
DOI: 10.1364/AO.55.005082
Publisher: SPIE
Date: 07-11-2018
DOI: 10.1117/12.2325525
Publisher: Hindawi Limited
Date: 2013
DOI: 10.1155/2013/470241
Abstract: The aim of this work is to develop a numerical model of Corrugated Wire Mesh Laminate (CWML) capturing all its complexities such as nonlinear material properties, nonlinear geometry and large deformation behaviour, and frictional behaviour. Development of such a model will facilitate numerical simulation of the mechanical behaviour of the wire mesh structure under various types of loading as well as the variation of the CWML configuration parameters to tailor its mechanical properties to suit the intended application. Starting with a single strand truss model consisting of four waves with a bilinear stress-strain model to represent the plastic behaviour of stainless steel, the finite element model is gradually built up to study single-layer structures with 18 strands of corrugated wire meshes consistency and double- and quadruple-layered laminates with alternating crossply orientations. The compressive behaviour of the CWML model is simulated using contact elements to model friction and is compared to the load-deflection behaviour determined experimentally in uniaxial compression tests. The numerical model of the CWML is then employed to conduct the aim of establishing the upper and lower bounds of stiffness and load capacity achievable by such structures.
Publisher: Wiley
Date: 03-2017
DOI: 10.1002/IMA.22209
Publisher: Elsevier BV
Date: 07-2014
DOI: 10.1016/J.JBIOMECH.2014.04.040
Abstract: The precise mechanism of bitemporal hemianopia (a type of partial visual field defect) is still not clear. Previous work has investigated this problem by studying the biomechanics of chiasmal compression caused by a pituitary tumour growing up from below the optic chiasm. A multi-scale analysis was performed using finite element models to examine both the macro-scale behaviour of the chiasm and the micro-scale interactions of the nerve fibres within it using representative volume elements. Possible effects of large deflection and non-linear material properties were incorporated. Strain distributions in the optic chiasm and optic nerve fibres were obtained from these models. The results of the chiasmal model agreed well with the limited experimental results available, indicating that the finite element modelling can be a useful tool for analysing chiasmal compression. Simulation results showed that the strain distribution in nasal (crossed) nerve fibres was much more nonuniform and locally higher than in temporal (uncrossed) nerve fibres. This strain difference between nasal and temporal nerve fibres may account for the phenomenon of bitemporal hemianopia.
Publisher: SPIE
Date: 17-03-2015
DOI: 10.1117/12.2081989
Publisher: SAGE Publications
Date: 20-05-2016
Abstract: Delamination is a common damage in fibre reinforced composite laminates, usually hidden from external view, that can substantially reduce the structural stiffness which changes the dynamic response of the structures such as natural frequencies. Natural frequencies are the most reliable parameters for detecting damage while they do not directly provide information regarding its location and severity. To determine the location and severity of damage, it is necessary to solve the inverse problem using frequency shifts in multiple modes. In this paper, the graphical approach, which was previously employed for estimating two variables of crack (location and size) in isotropic beams, is extended in the current work to estimate the three variables of delamination (interface, span-wise location and size) in anisotropic composite beams from measured frequency shifts. Compared to the use of optimisation or neural network for detection, graphical technique is computationally inexpensive and quick since it solves the inverse problem without iterations or network training. The present approach has been validated using numerical simulation as well as experimental data from modal testing conducted on quasi-isotropic simply supported and cantilever beams. Results show that the proposed graphical technique can be used to assess the location and severity of delamination in composite beams with a high degree of accuracy.
Publisher: Elsevier BV
Date: 03-2022
Publisher: SAGE Publications
Date: 28-04-2021
DOI: 10.1177/10775463211010535
Abstract: There are potential sources of uncertainty when using default or generic profiles for vibration testing, particularly for large and complex payloads ( Warren and Joiner, 2019 ). Replacing these severities with custom profiles generated using measured data offers one alternative however, care must be taken not to select an inappropriate or inaccurate method. This research details the methodology and results of a trial which involved the design and implementation of a series of vibration tests, each to simulate a mixed-terrain environment applied to a complex payload. A systematic approach was used to develop and execute a test plan via the design of experiments method. An estimate of the damage potential for each was formed using Miner’s rule (linear damage accumulation) applied to direct strain gauge data. This approach was compared with damage measured during a time waveform replication style test to be used as a baseline. The results of this test can be used to guide test specifiers and programme-level acceptance test guidelines and may be useful in implementing or guiding standards in this space. In addition, the damage measured in a series of increasing litude vibration tests (with an identical power spectral density) was compared with predicted values to assess the gain linearity assumptions often used in accelerated vibration testing. The research is unique as the authors could not source a thorough trial comparing the damage produced using a range of different profile development methods with a complex, real-world payload. Test houses and test specifiers seeking to improve the accuracy of their tests should consider the key findings and guidance in this article.
Publisher: Springer Science and Business Media LLC
Date: 2012
Publisher: Association for Computing Machinery (ACM)
Date: 17-04-2021
DOI: 10.1145/3446370
Abstract: Nowadays, robots are dominating the manufacturing, entertainment, and healthcare industries. Robot vision aims to equip robots with the capabilities to discover information, understand it, and interact with the environment, which require an agent to effectively understand object affordances and functions in complex visual domains. In this literature survey, first, “visual affordances” are focused on and current state-of-the-art approaches for solving relevant problems as well as open problems and research gaps are summarized. Then, sub-problems, such as affordance detection, categorization, segmentation, and high-level affordance reasoning, are specifically discussed. Furthermore, functional scene understanding and its prevalent descriptors used in the literature are covered. This survey also provides the necessary background to the problem, sheds light on its significance, and highlights the existing challenges for affordance and functionality learning.
Publisher: IEEE
Date: 29-11-2020
Publisher: IEEE
Date: 17-10-2021
Publisher: EJournal Publishing
Date: 2015
Publisher: Elsevier BV
Date: 05-2022
Publisher: The Optical Society
Date: 31-03-2017
Publisher: IEEE
Date: 11-2016
Publisher: IEEE
Date: 11-2021
Publisher: IEEE
Date: 10-2015
Publisher: ACM
Date: 06-06-2013
Publisher: Springer International Publishing
Date: 2014
Publisher: IEEE
Date: 12-2013
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 12-2014
Publisher: The Optical Society
Date: 21-08-2014
DOI: 10.1364/AO.53.005576
Publisher: OSA
Date: 2016
Publisher: Elsevier BV
Date: 09-2016
DOI: 10.1016/J.JMIR.2016.05.004
Abstract: In this article we systematically evaluate the performance of several state-of-the-art, sparsity prior computed tomography (CT) reconstruction algorithms, using a nonstandard simultaneous x-ray acquisition method. Sparsity prior is an efficient strategy in CT reconstruction, relying on iterative algorithms such as the algebraic reconstruction technique to produce a crude reconstruction, based on which sparse approximation is performed. The simultaneous x-ray acquisition model ensures rapid capture of x-rays however, it captures a significantly fewer number of attenuation measurements, and the projections are nonuniform. We propose a weighted average filter in the reconstruction framework to ensure better quality reconstruction by minimizing the effect of nonuniform projections. The performance of the state-of-the-art algorithms is analyzed with and without weighted averaging before sparse approximation, in simulated and real environments. Experiments in the simulated environment are conducted with and without the presence of noise. From the results, it is evident that sparsity prior algorithms are capable of producing cross-sectional reconstruction using the simultaneous x-ray acquisition model, and better reconstruction quality is achievable with the incorporation of weighted averaging in the reconstruction framework.
Publisher: IEEE
Date: 11-2005
Publisher: SPIE
Date: 15-10-2012
DOI: 10.1117/12.928899
Publisher: Informa UK Limited
Date: 30-11-2015
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2020
Publisher: SPIE
Date: 29-03-2016
DOI: 10.1117/12.2217770
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 19-10-2015
Abstract: Hemidecussation of fibers entering the optic chiasm from the optic nerves is well recognized. The reason why bitemporal hemianopia results from chiasmal compression has not been fully explained. There is still a paucity of data relating to the precise details of the routes that the nerve fibers take through the chiasm and, in particular, where and how nerve fibers cross each other. This information is important to understanding why crossing fibers are selectively damaged as a result of chiasmal compression. An optic chiasm obtained at postmortem was fixed, stained, and sectioned to allow high-resolution photomicrographs to be taken. The photomicrographs were integrated to allow regions of interest across entire sections to be analyzed for fiber direction and crossing. The results confirmed that fibers from the temporal retina pass directly backward in the lateral chiasm to the optic tract, whereas fibers from the nasal retina cross to the contralateral optic tract. Crossings take place in the paracentral regions of the chiasm rather than in the center of the chiasm (where the nerve fibers are traveling mostly in parallel). The paracentral crossing regions are distributed in a largely postero-superior to antero-inferior arrangement. These findings clarify the precise locations and crossing angles of crossing nerve fibers in the chiasm. This information may help explain the clinical observation of junctional scotoma and will provide a much better basis for structural modeling of chiasmal compression which, in turn, will improve our understanding of how and why bitemporal hemianopia occurs.
Publisher: American Institute of Aeronautics and Astronautics
Date: 02-01-2016
DOI: 10.2514/6.2016-1152
Publisher: Elsevier BV
Date: 07-2021
Publisher: Elsevier BV
Date: 02-2022
Publisher: IEEE
Date: 09-2010
Publisher: SPIE
Date: 18-03-2015
DOI: 10.1117/12.2082361
Publisher: IEEE
Date: 05-2015
Publisher: IEEE
Date: 10-2013
Publisher: SPIE
Date: 06-09-2017
DOI: 10.1117/12.2277180
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2020
Publisher: Springer International Publishing
Date: 2019
Publisher: Springer International Publishing
Date: 2013
Publisher: The Optical Society
Date: 16-10-2014
DOI: 10.1364/AO.53.007087
Publisher: IEEE
Date: 12-2013
Publisher: SPIE
Date: 16-04-2014
DOI: 10.1117/12.2064409
Publisher: Elsevier BV
Date: 2020
Publisher: IEEE
Date: 12-2017
Publisher: Research Square Platform LLC
Date: 14-09-2020
DOI: 10.21203/RS.3.RS-59641/V1
Abstract: Background Diet is central to treatment of type 2 diabetes. This review aimed to compare the effectiveness of nutrition therapy delivered by dietitians to nutrition advice delivered by other healthcare professionals in adults with type 2 diabetes on metabolic parameters. Methods Cochrane CENTRAL, CINAHL, EMBASE, MEDLINE and PsychINFO were searched for randomised controlled trials of three months duration or longer, published from 1st January 2008 to 18th June 2019. Relevant data were extracted from studies with additional author information. Random-effects meta-analysis assessed mean changes in HbA1c and other clinical parameters. PROSPERO registration number: CRD42019130528. Results Of 2477 records identified, fourteen studies (n = 3338) were eligible for qualitative synthesis and meta-analysis. The mean changes [95% CI] at follow-up in HbA1c, BMI, weight, LDL cholesterol, systolic and diastolic blood pressure were − 0·47 [-0·92, -0·02] %, -0·38 [-0·63, -0·13] kg/m 2 , -1·49 [-2·14, -0·84] kg, -0·15 [-0·33, 0·04] mmol/L, -0·75 [-2·45, 0·96] mm Hg and − 1·17 [-4·52, 2·17] mm Hg respectively in favour of the intervention group. Conclusions Nutrition therapy provided by dietitians was associated with better clinical parameters of type 2 diabetes, including clinically significant improved glycaemic control, across erse multiethnic patient groups from all six inhabited continents. This conclusion should be reflected in clinical guidelines.
Publisher: SPIE
Date: 12-11-2019
DOI: 10.1117/12.2547475
Publisher: IGI Global
Date: 2016
Publisher: SPIE
Date: 19-08-2010
DOI: 10.1117/12.860875
Publisher: SPIE
Date: 06-09-2017
DOI: 10.1117/12.2277179
Publisher: SPIE
Date: 11-09-2018
DOI: 10.1117/12.2322080
Publisher: SPIE
Date: 23-09-2014
DOI: 10.1117/12.2061891
Publisher: IEEE
Date: 11-2015
Publisher: Springer Science and Business Media LLC
Date: 02-11-2017
DOI: 10.1007/S13246-017-0595-6
Abstract: Ischaemic stroke is a major public health issue in both developed and developing nations. Hypothermia is believed to be neuroprotective in cerebral ischaemia. Conversely, elevated brain temperature is associated with poor outcome after ischaemic stroke. Mechanisms of heat exchange in normally-perfused brain are relatively well understood, but these mechanisms have not been studied as extensively during focal cerebral ischaemia. A finite element model (FEM) of heat exchange during focal ischaemia in the human brain was developed, based on the Pennes bioheat equation. This model incorporated healthy (normally-perfused) brain tissue, tissue that was mildly hypoperfused but not at risk of cell death (referred to as oligaemia), tissue that was hypoperfused and at risk of death but not dead (referred to as penumbra) and tissue that had died as a result of ischaemia (referred to as infarct core). The results of simulations using this model were found to match previous in-vivo temperature data for normally-perfused brain. However, the results did not match what limited data are available for hypoperfused brain tissue, in particular the penumbra, which is the focus of acute neuroprotective treatments such as hypothermia. These results suggest that the assumptions of the Pennes bioheat equation, while valid in the brain under normal circumstances, are not valid during focal ischaemia. Further investigation into the heat exchange profiles that do occur during focal ischaemia may yield results for clinical trials of therapeutic hypothermia.
No related grants have been discovered for Murat Tahtali.