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Using a gradient-based algorithm, we investigate signal estimation and filtering in a large-scale summing network of single-bit quantizers. Besides adjusting weights, the proposed learning algorithm also adaptively updates the level of added noise components that are intentionally injected into quantizers. Experimental results show that minimization of the mean-squared error requires a nonzero optimal level of the added noise. The process adaptively achieves in this way a form of stochastic resonance or noise-aided signal processing. This adaptive optimization method of the level of added noise extends the application of adaptive stochastic resonance to some complex nonlinear signal processing tasks.
Fei Li; Fabing Duan; François Chapeau-Blondeau; Derek Abbott. Signal estimation and filtering from quantized observations via adaptive stochastic resonance. Physical Review E 2021, 103, 052108 .
AMA StyleFei Li, Fabing Duan, François Chapeau-Blondeau, Derek Abbott. Signal estimation and filtering from quantized observations via adaptive stochastic resonance. Physical Review E. 2021; 103 (5):052108.
Chicago/Turabian StyleFei Li; Fabing Duan; François Chapeau-Blondeau; Derek Abbott. 2021. "Signal estimation and filtering from quantized observations via adaptive stochastic resonance." Physical Review E 103, no. 5: 052108.
Over the last decade, dc-dc power converters have attracted significant attention due to their increased use in a number of applications from aerospace to renewable energy. The interest in wide bandgap (WBG) power semiconductor devices stems from outstanding features of WBG materials, power device operation at higher temperatures, larger breakdown voltages, and the ability to sustain larger switching transients than silicon (Si) devices. As a result, recent progress and development of converter topologies, based on WBG power devices, are well-established for power conversion applications in which classical Si-based power devices show limited operation. Currently, Si carbide (SiC) and gallium nitride (GaN) are the most promising semiconductor materials that are being considered for the new generation of power devices. The use of new power semiconductor devices, such as GaN high electron mobility transistors (GaN HEMTs), leads to minimization of switching losses, allowing high switching frequencies (from kHz to MHz) for realizing compact power converters. Finally, design recommendations and future research trends are also presented.
Mohammad Parvez; Aaron T. Pereira; Nesimi Ertugrul; Neil H. E. Weste; Derek Abbott; Said F. Al-Sarawi. Wide Bandgap DC–DC Converter Topologies for Power Applications. Proceedings of the IEEE 2021, 109, 1253 -1275.
AMA StyleMohammad Parvez, Aaron T. Pereira, Nesimi Ertugrul, Neil H. E. Weste, Derek Abbott, Said F. Al-Sarawi. Wide Bandgap DC–DC Converter Topologies for Power Applications. Proceedings of the IEEE. 2021; 109 (7):1253-1275.
Chicago/Turabian StyleMohammad Parvez; Aaron T. Pereira; Nesimi Ertugrul; Neil H. E. Weste; Derek Abbott; Said F. Al-Sarawi. 2021. "Wide Bandgap DC–DC Converter Topologies for Power Applications." Proceedings of the IEEE 109, no. 7: 1253-1275.
Note: In lieu of an abstract, this is an excerpt from the first page. This paper
Jakeya Sultana; Saiful Islam; Cristiano M. B. Cordeiro; Alex Dinovitser; Mayank Kaushik; Brian W.-H. Ng; Derek Abbott. Addendum: Sultana, J., et al. Terahertz Hollow Core Antiresonant Fiber with Metamaterial Cladding. Fibers 2020, 8, 14. Fibers 2021, 9, 20 .
AMA StyleJakeya Sultana, Saiful Islam, Cristiano M. B. Cordeiro, Alex Dinovitser, Mayank Kaushik, Brian W.-H. Ng, Derek Abbott. Addendum: Sultana, J., et al. Terahertz Hollow Core Antiresonant Fiber with Metamaterial Cladding. Fibers 2020, 8, 14. Fibers. 2021; 9 (3):20.
Chicago/Turabian StyleJakeya Sultana; Saiful Islam; Cristiano M. B. Cordeiro; Alex Dinovitser; Mayank Kaushik; Brian W.-H. Ng; Derek Abbott. 2021. "Addendum: Sultana, J., et al. Terahertz Hollow Core Antiresonant Fiber with Metamaterial Cladding. Fibers 2020, 8, 14." Fibers 9, no. 3: 20.
Remaining useful life (RUL) prediction methods for rotating machines have been successfully developed in recent decades. More attention should be paid to predictions with inconsistent data distributions under different conditions. To solve this problem, this article proposes a new RUL prediction method that includes two phases. In the first phase, degradation features are extracted from both the training and testing data sets using probabilistic principal component analysis (PPCA). In the second phase, additive white Gaussian noise (AWGN) is intentionally injected into the degradation features; thereafter, the features that are mixed with manually injected noise are imported into a bidirectional long short-term memory (BLSTM) network. The AWGN can enhance the robustness of the RUL prediction method and achieve prediction for machines under different conditions. In contrast to most deep learning-based RUL prediction methods, the training samples are intentionally “polluted” by manually injected noise. The effectiveness of the proposed method is validated using the C-MAPSS lifetime data set for aeroengines and compared with the effectiveness of state-of-the-art approaches.
Lei Xiao; Fabing Duan; Junxuan Tang; Derek Abbott. A Noise-Boosted Remaining Useful Life Prediction Method for Rotating Machines Under Different Conditions. IEEE Transactions on Instrumentation and Measurement 2021, 70, 1 -12.
AMA StyleLei Xiao, Fabing Duan, Junxuan Tang, Derek Abbott. A Noise-Boosted Remaining Useful Life Prediction Method for Rotating Machines Under Different Conditions. IEEE Transactions on Instrumentation and Measurement. 2021; 70 ():1-12.
Chicago/Turabian StyleLei Xiao; Fabing Duan; Junxuan Tang; Derek Abbott. 2021. "A Noise-Boosted Remaining Useful Life Prediction Method for Rotating Machines Under Different Conditions." IEEE Transactions on Instrumentation and Measurement 70, no. : 1-12.
Vibrational resonance (VR) intentionally applies high-frequency periodic vibrations to a nonlinear system, in order to obtain enhanced efficiency for a number of information processing tasks. Note that VR is analogous to stochastic resonance where enhanced processing is sought via purposeful addition of a random noise instead of deterministic high-frequency vibrations. Comparatively, due to its ease of implementation, VR provides a valuable approach for nonlinear signal processing, through detailed modalities that are still under investigation. In this paper, VR is investigated in arrays of nonlinear processing devices, where a range of high-frequency sinusoidal vibrations of the same amplitude at different frequencies are injected and shown capable of enhancing the efficiency for estimating unknown signal parameters or for detecting weak signals in noise. In addition, it is observed that high-frequency vibrations with differing frequencies can be considered, at the sampling times, as independent random variables. This property allows us here to develop a probabilistic analysis—much like in stochastic resonance—and to obtain a theoretical basis for the VR effect and its optimization for signal processing. These results provide additional insight for controlling the capabilities of VR for nonlinear signal processing. This article is part of the theme issue ‘Vibrational and stochastic resonance in driven nonlinear systems (part 1)’.
Yan Pan; Fabing Duan; François Chapeau-Blondeau; Liyan Xu; Derek Abbott. Study of vibrational resonance in nonlinear signal processing. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 2021, 379, 20200235 .
AMA StyleYan Pan, Fabing Duan, François Chapeau-Blondeau, Liyan Xu, Derek Abbott. Study of vibrational resonance in nonlinear signal processing. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences. 2021; 379 (2192):20200235.
Chicago/Turabian StyleYan Pan; Fabing Duan; François Chapeau-Blondeau; Liyan Xu; Derek Abbott. 2021. "Study of vibrational resonance in nonlinear signal processing." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 379, no. 2192: 20200235.
Fig. 4 in reference [1] is after [2] .
Saiful Islam; Cristiano M. B. Cordeiro; J. Nine; Jakeya Sultana; Alice L. S. Cruz; Alex Dinovitser; Brian Wai-Him Ng; Heike Ebendorff-Heidepriem; Dusan Losic; Derek Abbott. Correction to: “Experimental Study on Glass and Polymers: Determining the Optimal Material for Potential Use in Terahertz Technology”. IEEE Access 2021, 9, 2705 -2705.
AMA StyleSaiful Islam, Cristiano M. B. Cordeiro, J. Nine, Jakeya Sultana, Alice L. S. Cruz, Alex Dinovitser, Brian Wai-Him Ng, Heike Ebendorff-Heidepriem, Dusan Losic, Derek Abbott. Correction to: “Experimental Study on Glass and Polymers: Determining the Optimal Material for Potential Use in Terahertz Technology”. IEEE Access. 2021; 9 ():2705-2705.
Chicago/Turabian StyleSaiful Islam; Cristiano M. B. Cordeiro; J. Nine; Jakeya Sultana; Alice L. S. Cruz; Alex Dinovitser; Brian Wai-Him Ng; Heike Ebendorff-Heidepriem; Dusan Losic; Derek Abbott. 2021. "Correction to: “Experimental Study on Glass and Polymers: Determining the Optimal Material for Potential Use in Terahertz Technology”." IEEE Access 9, no. : 2705-2705.
A hollow core antiresonant photonic crystal fiber (HC-ARPCF) is analyzed for terahertz applications. A numerical analysis of the proposed fiber is first carried out to minimize coupling between the core and cladding modes. The modeling of the scaled-up and inhibited coupling fiber is carried out by means of a Finite Element Method (FEM), which is then demonstrated using a Zeonex filament fiber, fabricated by fused deposition modeling (FDM) of 3D printing technology. The simulation is carried out to analyze both the transmission and possibility of refractometric sensing, whereas, the experimental analysis is carried out using terahertz time domain spectroscopy (THz-TDS), and supports our numerical findings, illustrating how the proposed fibers can be used for low loss transmission of terahertz waves. The simplicity of the proposed fiber structures facilitates fabrication for a number of different transmission and sensing applications in the terahertz range.
Jakeya Sultana; Saiful Islam; Cristiano M. B. Cordeiro; Selim Habib; Alex Dinovitser; Mayank Kaushik; Brian Wai-Him Ng; Heike Ebendorff-Heidepriem; Derek Abbott. Hollow Core Inhibited Coupled Antiresonant Terahertz Fiber: A Numerical and Experimental Study. IEEE Transactions on Terahertz Science and Technology 2020, 11, 245 -260.
AMA StyleJakeya Sultana, Saiful Islam, Cristiano M. B. Cordeiro, Selim Habib, Alex Dinovitser, Mayank Kaushik, Brian Wai-Him Ng, Heike Ebendorff-Heidepriem, Derek Abbott. Hollow Core Inhibited Coupled Antiresonant Terahertz Fiber: A Numerical and Experimental Study. IEEE Transactions on Terahertz Science and Technology. 2020; 11 (3):245-260.
Chicago/Turabian StyleJakeya Sultana; Saiful Islam; Cristiano M. B. Cordeiro; Selim Habib; Alex Dinovitser; Mayank Kaushik; Brian Wai-Him Ng; Heike Ebendorff-Heidepriem; Derek Abbott. 2020. "Hollow Core Inhibited Coupled Antiresonant Terahertz Fiber: A Numerical and Experimental Study." IEEE Transactions on Terahertz Science and Technology 11, no. 3: 245-260.
Autophagy, or cellular self-digestion, is an essential process for eliminating abnormal protein in mammalian cells. Accumulating evidence indicates that increased neuronal autophagy has a protective effect on neurodegenerative disorders. It has been reported that low-intensity pulsed ultrasound (LIPUS) can non-invasively modulate neural activity in the brain. Yet, the effect of LIPUS on neuronal autophagy is still unclear. The objective of this study was to examine whether LIPUS stimulation could induce neuronal autophagy. Primary neurons were treated by LIPUS with frequency of 0.68 MHz, pulse repetition frequency (PRF) of 500 Hz, spatial peak temporal-average intensities (ISPTA) of 70 and 165 mW/cm2. Then immunofluorescent analysis of LC3B was carried out for evaluating neuronal autophagy. Further, 0.5 MHz LIPUS was non-invasively delivered to the cortex and hippocampus of adult mice (n = 16) with PRF of 500 Hz and ISPTA of 235 mW/cm2. The LC3BII/LC3BI ratio and p62 (autophagic markers) were measured by western blot analysis. In in vitro study, the expression of LC3B in primary neurons was statistically improved after LIPUS stimulation was implemented for 4 hours (p < 0.01). With the increase of irradiation duration or acoustic intensity of LIPUS stimulation, the expression of LC3B in primary neurons was increased. Furthermore, transcranial LIPUS stimulation increased the LC3BII/LC3BI ratio (p < 0.05), and decreased the expression of p62 (p < 0.05) in the cortex and hippocampus. We concluded that LIPUS provides a safe and capable tool for activating neuronal autophagy in vitro and in vivo.
Xiaowei Huang; Lili Niu; Long Meng; Zhengrong Lin; Wei Zhou; Xiufang Liu; Jiqing Huang; Derek Abbott; Hairong Zheng. Transcranial Low-Intensity Pulsed Ultrasound Stimulation Induces Neuronal Autophagy. IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control 2020, 68, 46 -53.
AMA StyleXiaowei Huang, Lili Niu, Long Meng, Zhengrong Lin, Wei Zhou, Xiufang Liu, Jiqing Huang, Derek Abbott, Hairong Zheng. Transcranial Low-Intensity Pulsed Ultrasound Stimulation Induces Neuronal Autophagy. IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control. 2020; 68 (1):46-53.
Chicago/Turabian StyleXiaowei Huang; Lili Niu; Long Meng; Zhengrong Lin; Wei Zhou; Xiufang Liu; Jiqing Huang; Derek Abbott; Hairong Zheng. 2020. "Transcranial Low-Intensity Pulsed Ultrasound Stimulation Induces Neuronal Autophagy." IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control 68, no. 1: 46-53.
In the past few decades, numerous studies have demonstrated the effectiveness of diet modification in preventing and controlling different chronic diseases, bringing increased attention to the creation of nutritional recipes. Currently, the development of recipes is primarily based on personal experience rather than nutritional specifications. To this end, this paper first uses kernel canonical correlation analysis to demonstrate the relationship between nutrients in food and recipes. Based on this relationship, a new recipe expression method is put forward, which objectively reflects differing importance of an ingredient in differing recipes. Then, recipes are composed using an auto-encoder in deep learning, and a fusion model of two auto-encoders is proposed for better concocting recipes. This paper uses two machine learning methods, namely, non-negative matrix factorization and two-step regularized least squares, to form recipes. To tackle overfitting and instability in non-negative matrix factorization during the training of recipe model, we introduce the Frobenius norm to redefine the objective function and add non-smooth sparse matrices. Similar food has similar taste, but their nutrients might differ. This paper also considers nutrients as a kernel matrix of the two-step regularized least squares, which can effectively avoid the occurrence of different food combinations with similar taste. Experimental results show that developing recipes based on nutrients in food is feasible and effective in the context of machine learning.
Zhenfeng Lei; Anwar Ul Haq; Mohsen Dorraki; Defu Zhang; Derek Abbott. Composing recipes based on nutrients in food in a machine learning context. Neurocomputing 2020, 415, 382 -396.
AMA StyleZhenfeng Lei, Anwar Ul Haq, Mohsen Dorraki, Defu Zhang, Derek Abbott. Composing recipes based on nutrients in food in a machine learning context. Neurocomputing. 2020; 415 ():382-396.
Chicago/Turabian StyleZhenfeng Lei; Anwar Ul Haq; Mohsen Dorraki; Defu Zhang; Derek Abbott. 2020. "Composing recipes based on nutrients in food in a machine learning context." Neurocomputing 415, no. : 382-396.
We propose and numerically analyze various hollow-core antiresonant fiber (HC-ARF) for operation at terahertz frequencies. We compare typical HC-ARF designs with nested and adjacent nested designs while analyzing performance in terms of loss and single-mode guidance of terahertz waves. With optimized fiber dimensions, the fundamental core mode, cladding mode, core higher-order modes (HOMs), and the angle dependence of adjacent tubes are analyzed to find the best design for low loss terahertz transmission. Analysis of the fiber designs shows that the nested tube-based antiresonant fiber exhibits lower transmission loss and superior HOM suppression, exceeding 140. The nested HC-ARF is feasible for fabrication using existing fabrication technologies and opening up the possibility of efficient transmission of terahertz waves.
Jakeya Sultana; Saiful Islam; Cristiano M. B. Cordeiro; Selim Habib; Alex Dinovitser; Brian Wai-Him Ng; Derek Abbott. Exploring Low Loss and Single Mode in Antiresonant Tube Lattice Terahertz Fibers. IEEE Access 2020, 8, 113309 -113317.
AMA StyleJakeya Sultana, Saiful Islam, Cristiano M. B. Cordeiro, Selim Habib, Alex Dinovitser, Brian Wai-Him Ng, Derek Abbott. Exploring Low Loss and Single Mode in Antiresonant Tube Lattice Terahertz Fibers. IEEE Access. 2020; 8 ():113309-113317.
Chicago/Turabian StyleJakeya Sultana; Saiful Islam; Cristiano M. B. Cordeiro; Selim Habib; Alex Dinovitser; Brian Wai-Him Ng; Derek Abbott. 2020. "Exploring Low Loss and Single Mode in Antiresonant Tube Lattice Terahertz Fibers." IEEE Access 8, no. : 113309-113317.
Si $_3$ N $_4$ has emerged as a prominent material for expanding the capability of silicon photonics to wavelengths below < 1 μm. However, realizing an efficient optical modulator, a key building block for any integrated optics platform, remains a major challenge in Si $_3$ N $_4$ mainly because this material has a vanishing Pockels coefficient. Here, we propose a compact Si $_3$ N $_4$ —based optical modulator by using a thin VO2 layer on top of a Si3N4 strip waveguide where amplitude modulation is achieved via phase transition of the VO2 layer. To reduce the actuation time of the temperature-induced VO2 phase transition, a mono-layer graphene microheater is designed for the active Si $_3$ N $_4$ —VO2 waveguide. Our simulations indicate a high extinction ratio of∼8.28 dB/μm with an insertion loss of ∼2.8 dB/μm at the design wavelength of 850 nm for the proposed modulator and wideband operation in the wavelength range of 800—900 nm. It is shown that employing the electrical and thermal properties of graphene not only leads to a significant reduction of the power consumption of the device but also, decreases the actuation time compared to previous modulators based on the thermal phase transition of the VO2.
Babak Janjan; Mehdi Miri; Davood Fathi; Mohsen Heidari; Derek Abbott. Hybrid Si$_3$N$_4$/VO$_2$ Modulator Thermally Triggered by a Graphene Microheater. IEEE Journal of Selected Topics in Quantum Electronics 2020, 26, 1 -6.
AMA StyleBabak Janjan, Mehdi Miri, Davood Fathi, Mohsen Heidari, Derek Abbott. Hybrid Si$_3$N$_4$/VO$_2$ Modulator Thermally Triggered by a Graphene Microheater. IEEE Journal of Selected Topics in Quantum Electronics. 2020; 26 (5):1-6.
Chicago/Turabian StyleBabak Janjan; Mehdi Miri; Davood Fathi; Mohsen Heidari; Derek Abbott. 2020. "Hybrid Si$_3$N$_4$/VO$_2$ Modulator Thermally Triggered by a Graphene Microheater." IEEE Journal of Selected Topics in Quantum Electronics 26, no. 5: 1-6.
The composition of an atherosclerotic plaque is a major determinant of its vulnerability, i.e. proneness to rupture. This paper proposes an ultrasonic texture matching method, which is shown to reflect the distribution of elastic modulus and is a potential method for quantitatively analyzing different plaque components based on B-mode cine-loops. We performed an in vitro study, employing plaque phantoms fabricated using polyvinyl alcohol. Firstly, the phantoms with two components (soft tissue: 60.9 ± 6.8 kPa; surrounding tissue: 248.8 ± 12.1 kPa) were fabricated. Soft tissue occupied 10%, 40% and 64% of the total plaque volume. Further, three tissue components (soft tissue: 60.9 ± 6.8 kPa; hard tissue: 248.8 ± 12.1 kPa; surrounding tissue: 310.3 ± 14.1 kPa) were made. Soft and hard tissues occupied 32% of total plaque volume, respectively. For our in vivo study, six mice with ApoE knockout and three New Zealand white rabbits with abdominal aortic balloon injury were evaluated. Ultrasound cine-loop data of plaques were collected to calculate elastic modulus, then the plaque tissues were removed for further histology examination. The cine-loop data in vitro study and in vivo study were acquired by an ultrasound micro-imaging system (VisualSonics Vevo2100). In the phantom experiment, the mean elastic moduli of two component phantoms were 60.4 ± 7.6 kPa (soft tissue) and 198.5 ± 12.5 kPa (surrounding tissue), respectively. Similarly, the mean elastic moduli of three component phantoms exhibited 90.2 ± 6.2 kPa (soft tissue), 184.3 ± 11.6 kPa (hard tissue) and 381.6 ± 3.8 kPa (surrounding tissue), respectively. In animal experiments, the percentage of lipid tissue and calcification regions was also quantified in mice and in rabbit experiment with the histological results. This suggests that the texture matching method may be a potential method to identify lipid component of plaque and to predict the vulnerability of atherosclerosis plaques noninvasively.
Hongyu Kang; Yanling Zhang; Xiaowei Huang; Lili Niu; Hui Zhang; Lisheng Xu; Derek Abbott. Quantification of Atherosclerotic Plaque Elasticity Using Ultrasonic Texture Matching. IEEE Access 2020, 8, 94268 -94278.
AMA StyleHongyu Kang, Yanling Zhang, Xiaowei Huang, Lili Niu, Hui Zhang, Lisheng Xu, Derek Abbott. Quantification of Atherosclerotic Plaque Elasticity Using Ultrasonic Texture Matching. IEEE Access. 2020; 8 (99):94268-94278.
Chicago/Turabian StyleHongyu Kang; Yanling Zhang; Xiaowei Huang; Lili Niu; Hui Zhang; Lisheng Xu; Derek Abbott. 2020. "Quantification of Atherosclerotic Plaque Elasticity Using Ultrasonic Texture Matching." IEEE Access 8, no. 99: 94268-94278.
The optical properties of polymers and glasses useful for terahertz applications are experimentally characterized using terahertz time-domain spectroscopy (THz-TDS). A standard system setup utilizing transmission spectroscopy is used to measure different optical properties of materials including refractive index, relative permittivity, loss tangent, absorption coefficient, and transmittance. The thermal and chemical dependencies of materials are also studied to identify the appropriate materials for given terahertz applications. The selected materials can then be utilized for applications such as in waveguides, filters, lenses, polarization preserving devices, metamaterials and metasurfaces, absorbers, and sensors in the terahertz frequency range.
Saiful Islam; Cristiano M. B. Cordeiro; M. J. Nine; Jakeya Sultana; Alice L. S. Cruz; Alex Dinovitser; Brian Wai-Him Ng; Heike Ebendorff-Heidepriem; Dusan Losic; Derek Abbott. Experimental Study on Glass and Polymers: Determining the Optimal Material for Potential Use in Terahertz Technology. IEEE Access 2020, 8, 97204 -97214.
AMA StyleSaiful Islam, Cristiano M. B. Cordeiro, M. J. Nine, Jakeya Sultana, Alice L. S. Cruz, Alex Dinovitser, Brian Wai-Him Ng, Heike Ebendorff-Heidepriem, Dusan Losic, Derek Abbott. Experimental Study on Glass and Polymers: Determining the Optimal Material for Potential Use in Terahertz Technology. IEEE Access. 2020; 8 (99):97204-97214.
Chicago/Turabian StyleSaiful Islam; Cristiano M. B. Cordeiro; M. J. Nine; Jakeya Sultana; Alice L. S. Cruz; Alex Dinovitser; Brian Wai-Him Ng; Heike Ebendorff-Heidepriem; Dusan Losic; Derek Abbott. 2020. "Experimental Study on Glass and Polymers: Determining the Optimal Material for Potential Use in Terahertz Technology." IEEE Access 8, no. 99: 97204-97214.
Nesimi Ertugrul; Derek Abbott. DC is the Future [Point of View]. Proceedings of the IEEE 2020, 108, 615 -624.
AMA StyleNesimi Ertugrul, Derek Abbott. DC is the Future [Point of View]. Proceedings of the IEEE. 2020; 108 (5):615-624.
Chicago/Turabian StyleNesimi Ertugrul; Derek Abbott. 2020. "DC is the Future [Point of View]." Proceedings of the IEEE 108, no. 5: 615-624.
Elevated blood pressure (BP) is a major cause of death, yet hypertension commonly goes undetected. Owing to its nature, it is typically asymptomatic until later in its progression when the vessel or organ structure has already been compromised. Therefore, noninvasive and continuous BP measurement methods are needed to ensure appropriate diagnosis and early management before hypertension leads to irreversible complications. Photoplethysmography (PPG) is a noninvasive technology with waveform morphologies similar to that of arterial BP waveforms, therefore attracting interest regarding its usability in BP estimation. In recent years, wearable devices incorporating PPG sensors have been proposed to improve the early diagnosis and management of hypertension. Additionally, the need for improved accuracy and convenience has led to the development of devices that incorporate multiple different biosignals with PPG. Through the addition of modalities such as an electrocardiogram, a final measure of the pulse wave velocity is derived, which has been proved to be inversely correlated to BP and to yield accurate estimations. This paper reviews and summarizes recent studies within the period 2010–2019 that combined PPG with other biosignals and offers perspectives on the strengths and weaknesses of current developments to guide future advancements in BP measurement. Our literature review reveals promising measurement accuracies and we comment on the effective combinations of modalities and success of this technology.
Kaylie Welykholowa; Manish Hosanee; Gabriel Chan; Rachel Cooper; Panayiotis A. Kyriacou; Dingchang Zheng; John Allen; Derek Abbott; Carlo Menon; Nigel H. Lovell; Newton Howard; Wee-Shian Chan; Kenneth Lim; Richard Fletcher; Rabab Ward; Mohamed Elgendi. Multimodal Photoplethysmography-Based Approaches for Improved Detection of Hypertension. Journal of Clinical Medicine 2020, 9, 1203 .
AMA StyleKaylie Welykholowa, Manish Hosanee, Gabriel Chan, Rachel Cooper, Panayiotis A. Kyriacou, Dingchang Zheng, John Allen, Derek Abbott, Carlo Menon, Nigel H. Lovell, Newton Howard, Wee-Shian Chan, Kenneth Lim, Richard Fletcher, Rabab Ward, Mohamed Elgendi. Multimodal Photoplethysmography-Based Approaches for Improved Detection of Hypertension. Journal of Clinical Medicine. 2020; 9 (4):1203.
Chicago/Turabian StyleKaylie Welykholowa; Manish Hosanee; Gabriel Chan; Rachel Cooper; Panayiotis A. Kyriacou; Dingchang Zheng; John Allen; Derek Abbott; Carlo Menon; Nigel H. Lovell; Newton Howard; Wee-Shian Chan; Kenneth Lim; Richard Fletcher; Rabab Ward; Mohamed Elgendi. 2020. "Multimodal Photoplethysmography-Based Approaches for Improved Detection of Hypertension." Journal of Clinical Medicine 9, no. 4: 1203.
Prediction of the severity of multipath fading is fundamental to the design of point-to-point terrestrial fixed microwave links at frequencies below 10 GHz, but error in this prediction may be significant in countries such as Australia, not represented in the dataset used to generate existing empirical models. We take advantage of recently collected worst-month fading data from Australia, and find new parameters particularly useful in predicting the severe fading experienced in Northern Australia. These parameters are from very irregularly spaced weather stations, so we investigate various interpolation techniques for this situation, including a new version of natural neighbour interpolation. Conventional multipath prediction models are based on ordinary least squares (OLS) regression, but we refine this, taking spatial correlation into account with generalised least squares (GLS) regression. We then demonstrate further improvement in regions well populated by measured data, by employing universal kriging.
Stephen J. Salamon; Hedley J. Hansen; Derek Abbott. Universal Kriging Prediction of Line-of-Sight Microwave Fading. IEEE Access 2020, 8, 74743 -74758.
AMA StyleStephen J. Salamon, Hedley J. Hansen, Derek Abbott. Universal Kriging Prediction of Line-of-Sight Microwave Fading. IEEE Access. 2020; 8 (99):74743-74758.
Chicago/Turabian StyleStephen J. Salamon; Hedley J. Hansen; Derek Abbott. 2020. "Universal Kriging Prediction of Line-of-Sight Microwave Fading." IEEE Access 8, no. 99: 74743-74758.
In this paper, a simple, fast, and novel method for designing a tunable terahertz absorber with arbitrary central frequency and desired fractional bandwidth is presented. The proposed absorber consists of a single layer periodic array of graphene ribbons (PAGRs), placed a quarter wavelength from a metallic ground, separated by a dielectric material. An analytical circuit model of the terahertz absorber is used to obtain analytical expressions for the input impedance of the proposed device. Then, a simple expression for determining the value of capacitance and the resonance conditions of the RLC circuit is used to achieve a terahertz absorber with arbitrary central frequency and desired fractional bandwidth. The proposed method is applicable for the design of both narrowband and broadband absorbers, with only one layer of graphene ribbons. Also, the presented method is applicable for designing ultra-wideband absorbers using multiple layered PAGRs. Full-wave numerical simulation is performed to verify the accuracy and validity of the presented method. Excellent performance of the proposed method in terms of computation time and memory resource and providing the desired terahertz absorber characteristics shows that our method is promising as a design approach for sensing, imaging and filtering applications.
Mohammad Biabanifard; Arash Arsanjani; Mohammad Sadegh Abrishamian; Derek Abbott. Tunable Terahertz Graphene-Based Absorber Design Method Based on a Circuit Model Approach. IEEE Access 2020, 8, 70343 -70354.
AMA StyleMohammad Biabanifard, Arash Arsanjani, Mohammad Sadegh Abrishamian, Derek Abbott. Tunable Terahertz Graphene-Based Absorber Design Method Based on a Circuit Model Approach. IEEE Access. 2020; 8 (99):70343-70354.
Chicago/Turabian StyleMohammad Biabanifard; Arash Arsanjani; Mohammad Sadegh Abrishamian; Derek Abbott. 2020. "Tunable Terahertz Graphene-Based Absorber Design Method Based on a Circuit Model Approach." IEEE Access 8, no. 99: 70343-70354.
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Mohsen Dorraki; Andrew Allison; Derek Abbott. Publisher Correction: Truels and strategies for survival. Scientific Reports 2020, 10, 5094 -1.
AMA StyleMohsen Dorraki, Andrew Allison, Derek Abbott. Publisher Correction: Truels and strategies for survival. Scientific Reports. 2020; 10 (1):5094-1.
Chicago/Turabian StyleMohsen Dorraki; Andrew Allison; Derek Abbott. 2020. "Publisher Correction: Truels and strategies for survival." Scientific Reports 10, no. 1: 5094-1.
One in three adults worldwide has hypertension, which is associated with significant morbidity and mortality. Consequently, there is a global demand for continuous and non-invasive blood pressure (BP) measurements that are convenient, easy to use, and more accurate than the currently available methods for detecting hypertension. This could easily be achieved through the integration of single-site photoplethysmography (PPG) readings into wearable devices, although improved reliability and an understanding of BP estimation accuracy are essential. This review paper focuses on understanding the features of PPG associated with BP and examines the development of this technology over the 2010–2019 period in terms of validation, sample size, diversity of subjects, and datasets used. Challenges and opportunities to move single-site PPG forward are also discussed.
Manish Hosanee; Gabriel Chan; Kaylie Welykholowa; Rachel Cooper; Panayiotis A. Kyriacou; Dingchang Zheng; John Allen; Derek Abbott; Carlo Menon; Nigel H. Lovell; Newton Howard; Wee-Shian Chan; Kenneth Lim; Richard Fletcher; Rabab Ward; Mohamed Elgendi. Cuffless Single-Site Photoplethysmography for Blood Pressure Monitoring. Journal of Clinical Medicine 2020, 9, 723 .
AMA StyleManish Hosanee, Gabriel Chan, Kaylie Welykholowa, Rachel Cooper, Panayiotis A. Kyriacou, Dingchang Zheng, John Allen, Derek Abbott, Carlo Menon, Nigel H. Lovell, Newton Howard, Wee-Shian Chan, Kenneth Lim, Richard Fletcher, Rabab Ward, Mohamed Elgendi. Cuffless Single-Site Photoplethysmography for Blood Pressure Monitoring. Journal of Clinical Medicine. 2020; 9 (3):723.
Chicago/Turabian StyleManish Hosanee; Gabriel Chan; Kaylie Welykholowa; Rachel Cooper; Panayiotis A. Kyriacou; Dingchang Zheng; John Allen; Derek Abbott; Carlo Menon; Nigel H. Lovell; Newton Howard; Wee-Shian Chan; Kenneth Lim; Richard Fletcher; Rabab Ward; Mohamed Elgendi. 2020. "Cuffless Single-Site Photoplethysmography for Blood Pressure Monitoring." Journal of Clinical Medicine 9, no. 3: 723.
Angiogenesis, the formation of a network of blood vessels, is a vital process in the growth of solid tumors as it delivers required nutrients and oxygen. Prior medical studies assert that angiogenesis is influenced by a number of parameters such as endothelial cell migration and proliferation, existence of tumor angiogenesis factors, oxygen, extracellular matrix components, etc. Along with the early developments and findings in the area of tumor angiogenesis, a field of research that has emerged uses mathematical models to interpret and predict the time-course of the crucial factors, as well as new capillary vessel formation, loop formation, and vessel branching. However, most of these early mathematical approaches rely on a small number of parameters; and the characteristics of blood flow, which are significant factors in tumor vessel formation, are neglected. Relatively new integrated models based on the impact of multiple crucial factors and blood flow have seen some success in elucidating the behavior of angiogenesis. Here we review the contributions, opportunities, progress, and challenges of mathematical and computational models for understanding of the tumor-induced angiogenesis, and also consider studies that apply mathematical models to represent blood flow and opportunities for the investigation of therapies and treatments. At the same time, we identify a need for the inclusion of endothelial cell shape and dynamics in models of tumor-induced angiogenesis. Particularly, cell-matrix, cell shape, and cell-cell interaction is necessary for the explanation of blood vessel formation.
Mohsen Dorraki; Anahita Fouladzadeh; Andrew Allison; Claudine S. Bonder; Derek Abbott. Angiogenic Networks in Tumors—Insights via Mathematical Modeling. IEEE Access 2020, 8, 43215 -43228.
AMA StyleMohsen Dorraki, Anahita Fouladzadeh, Andrew Allison, Claudine S. Bonder, Derek Abbott. Angiogenic Networks in Tumors—Insights via Mathematical Modeling. IEEE Access. 2020; 8 (99):43215-43228.
Chicago/Turabian StyleMohsen Dorraki; Anahita Fouladzadeh; Andrew Allison; Claudine S. Bonder; Derek Abbott. 2020. "Angiogenic Networks in Tumors—Insights via Mathematical Modeling." IEEE Access 8, no. 99: 43215-43228.