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Azmat Ullah, Suheel Abdullah Malik, Khurram Saleem Alimgeer
In this paper, a hybrid heuristic scheme based on two different basis functions i.e. Log Sigmoid and Bernstein Polynomial with unknown parameters is used for solving the nonlinear heat transfer equations efficiently. The proposed technique transforms the given nonlinear ordinary differential equation into an equivalent global error minimization problem. Trial solution for the given nonlinear differential equation is formulated using a fitness function with unknown parameters. The proposed hybrid scheme of Genetic Algorithm (GA) with Interior Point Algorithm (IPA) is opted to solve the minimization problem and to achieve the optimal values of unknown parameters...
2018: PloS One
Marie Farge, Naoya Okamoto, Kai Schneider, Katsunori Yoshimatsu
We present numerical simulations of the three-dimensional Galerkin truncated incompressible Euler equations that we integrate in time while regularizing the solution by applying a wavelet-based denoising. For this, at each time step, the vorticity field is decomposed into wavelet coefficients, which are split into strong and weak coefficients, before reconstructing them in physical space to obtain the corresponding coherent and incoherent vorticities. Both components are multiscale and orthogonal to each other...
December 2017: Physical Review. E
Vladimir A Maksimenko, Annika Lüttjohann, Vladimir V Makarov, Mikhail V Goremyko, Alexey A Koronovskii, Vladimir Nedaivozov, Anastasia E Runnova, Gilles van Luijtelaar, Alexander E Hramov, Stefano Boccaletti
We introduce a practical and computationally not demanding technique for inferring interactions at various microscopic levels between the units of a network from the measurements and the processing of macroscopic signals. Starting from a network model of Kuramoto phase oscillators, which evolve adaptively according to homophilic and homeostatic adaptive principles, we give evidence that the increase of synchronization within groups of nodes (and the corresponding formation of synchronous clusters) causes also the defragmentation of the wavelet energy spectrum of the macroscopic signal...
July 2017: Physical Review. E
Berend Christopher Rinderspacher, Jaydeep P Bardhan, Ahmed E Ismail
We present a multiresolution approach to compressing the degrees of freedom and potentials associated with molecular dynamics, such as the bond potentials. The approach suggests a systematic way to accelerate large-scale molecular simulations with more than two levels of coarse graining, particularly applications of polymeric materials. In particular, we derive explicit models for (arbitrarily large) linear (homo)polymers and iterative methods to compute large-scale wavelet decompositions from fragment solutions...
July 2017: Physical Review. E
Adrien Deliège, Samuel Nicolay
This paper consists in the description and application of a method called wavelet-induced mode extraction (WIME) in the context of time-frequency analysis. WIME aims to extract the oscillating components that build amplitude modulated-frequency modulated signals. The essence of this technique relies on the successive extractions of the dominant ridges of wavelet-based time-frequency representations of the signal under consideration. Our tests on simulated examples indicate strong decomposition and reconstruction skills, trouble-free handling of crossing trajectories in the time-frequency plane, sharp performances in frequency detection in the case of mode-mixing problems, and a natural tolerance to noise...
September 2017: Physical Review. E
Hongmin Cai, Peihua Chen, Jiazhou Chen, Jiulun Cai, Yan Song, Guoqiang Han
Copy-number variations (CNVs) are associated with complex diseases and particular tumor types. Array-based comparative genomic hybridization (aCGH) is a common approach for the detection of CNVs. Traditional CNV detection methods for multiple aCGH samples mainly use batch samples to find common variations, not accounting for the individual characteristics of each sample. Accurately differentiating both the commonly shared and the individual CNV patterns is pivotal to identify cell populations, or to distinguish cell growth (as in cancer) from invasion of new cells...
February 2018: IEEE Transactions on Bio-medical Engineering
Bingxin Liu, Ying Li, Chengyu Liu, Feng Xie, Jan-Peter Muller
Researchers have studied oil spills in open waters using remote sensors, but few have focused on extracting reflectance features of oil pollution on sea ice. An experiment was conducted on natural sea ice in Bohai Bay, China, to obtain the spectral reflectance of oil-contaminated sea ice. The spectral absorption index (SAI), spectral peak height (SPH), and wavelet detail coefficient (DWT d5) were calculated using stepwise multiple linear regression. The reflectances of some false targets were measured and analysed...
January 15, 2018: Sensors
Andreu González-Calabuig, Xavier Cetó, Manel Del Valle
This work reports the applicability of a voltammetric sensor array able to quantify the content of 2,4-dinitrophenol, 4-nitrophenol, and picric acid in artificial samples using the electronic tongue (ET) principles. The ET is based on cyclic voltammetry signals, obtained from an array of metal disk electrodes and a graphite epoxy composite electrode, compressed using discrete wavelet transform with chemometric tools such as artificial neural networks (ANNs). ANNs were employed to build the quantitative prediction model...
January 13, 2018: Sensors
Qianying Liu, Bitian Wang, Ying Liu, Zeping Lv, Wenhao Li, Zengyong Li, Yubo Fan
A connectivity-based approach can highlight the network reorganization in the chronic phases after stroke and contributes to the development of therapeutic interventions. Using dynamic Bayesian inference, this study aimed to assess the effective connectivity(EC)in various frequency bands through the near-infrared spectroscopy(NIRS) method in subjects with cerebral infarction(CI). A phase-coupling model was established based on phase information extracted using the wavelet transform of NIRS signals. Coupling strength and the main coupling direction were estimated using dynamic Bayesian inference...
January 11, 2018: Neuroscience
Aditya Parekh, Debanjan Das, Subhayan Das, Santanu Dhara, Karabi Biswas, Mahitosh Mandal, Soumen Das
Determination of cancer aggressiveness is mainly assessed in tissues by looking at the grade of cancer. There is a lack of specific method to determine aggressiveness of cancer cells in vitro. In our present work, we have proposed a bio-impedance based non-invasive method to differentiate aggressive property of two breast cancer cell lines. Real-time impedance analysis of MCF-7 (less aggressive) and MDA-MB-231 cells (more aggressive) demonstrated unique growth pattern. Detailed slope-analysis of impedance curves at different growth phases showed that MDA-MB-231 had higher proliferation rate and intrinsic resistance to cell death, when allowed to grow in nutrient and space limiting conditions...
January 15, 2018: Scientific Reports
Yingxia Liu, Ziad Saleh, Yulin Song, Maria Chan, Xiang Li, Chengyu Shi, Xin Qian, Xiaoli Tang
Segmentation of prostate Cone Beam CT (CBCT) images is an essential step towards real-time adaptive radiotherapy (ART). It is challenging for Calypso patients, as more artifacts generated by the beacon transponders are present on the images. We herein propose a novel wavelet-based segmentation algorithm for rectum, bladder, and prostate of CBCT images with implanted Calypso transponders. For a given CBCT, a Moving Window-Based Double Haar (MWDH) transformation is applied first to obtain the wavelet coefficients...
August 2017: International Journal of Medical Physics, Clinical Engineering and Radiation Oncology
Mahsa Khalili, Mahmoud Reza Sohrabi, Vahid Mirzabeygi, Nahid Torabi Ziaratgahi
Partial least squares (PLS), different families of continuous wavelet transform (CWT), and first derivative spectrophotometry (DS) techniques were studied for quantification of Sofosbuvir (SFB) and Ledipasvir (LDV) simultaneously without separation step. The components were dissolved in Acetonitrile and the spectral behaviors were evaluated in the range of 200 to 400nm. The ultraviolet (UV) absorbance of LDV exhibits no interferences between 300 and 400nm and it was decided to predict the LDV amount through the classic spectrophotometry (CS) method in this spectral region as well...
January 6, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Qiuzhao Zhang, Wei Yang, Shubi Zhang, Xin Liu
Global Navigation Satellite System (GNSS) carrier phase measurement for short baseline meets the requirements of deformation monitoring of large structures. However, the carrier phase multipath effect is the main error source with double difference (DD) processing. There are lots of methods to deal with the multipath errors of Global Position System (GPS) carrier phase data. The BeiDou navigation satellite System (BDS) multipath mitigation is still a research hotspot because the unique constellation design of BDS makes it different to mitigate multipath effects compared to GPS...
January 12, 2018: Sensors
M Ibrahim, C I Pardi, T W C Brown, P J McDonald
Improvement in the signal-to-noise ratio of Nuclear Magnetic Resonance (NMR) systems may be achieved either by increasing the signal amplitude or by decreasing the noise. The noise has multiple origins - not all of which are strictly "noise": incoherent thermal noise originating in the probe and pre-amplifiers, probe ring down or acoustic noise and coherent externally broadcast radio frequency transmissions. The last cannot always be shielded in open access experiments. In this paper, we show that pulsed, low radio-frequency data communications are a significant source of broadcast interference...
January 7, 2018: Journal of Magnetic Resonance
Pavel A Cheremkhin, Ekaterina A Kurbatova
Compression of digital holograms can significantly help with the storage of objects and data in 2D and 3D form, its transmission, and its reconstruction. Compression of standard images by methods based on wavelets allows high compression ratios (up to 20-50 times) with minimum losses of quality. In the case of digital holograms, application of wavelets directly does not allow high values of compression to be obtained. However, additional preprocessing and postprocessing can afford significant compression of holograms and the acceptable quality of reconstructed images...
January 1, 2018: Applied Optics
Majid Masoumi, Mahsa Rezaei, A Ben Hamza
Quantitative shape comparison is a fundamental problem in computer vision, geometry processing and medical imaging. In this paper, we present a spectral graph wavelet approach for shape analysis of carpal bones of the human wrist. We employ spectral graph wavelets to represent the cortical surface of a carpal bone via the spectral geometric analysis of the Laplace-Beltrami operator in the discrete domain. We propose global spectral graph wavelet (GSGW) descriptor that is isometric invariant, efficient to compute, and combines the advantages of both low-pass and band-pass filters...
January 12, 2018: Physics in Medicine and Biology
Christopher Moufawad El Achkar, Constanze Lenbole-Hoskovec, Anisoara Paraschiv-Ionescu, Kristof Major, Kamiar Aminian, Christophe Büla
The frequency and quality of sit-to-stand and stand-to-sit postural transitions decrease with age and are highly relevant for fall risk assessment. Accurate classification and characterization of these transitions in daily life of older adults are therefore needed. In this study, we propose to use instrumented shoes for postural transition classification as well as transition duration estimation from insole force signals. In the first part, data were collected with 10 older adults and 10 young participants performing transitions in the laboratory while wearing the instrumented shoes, without arm assistance...
January 12, 2018: Medical & Biological Engineering & Computing
Florian Berg, Oda W Almeland, Julie Skadal, Aril Slotte, Leif Andersson, Arild Folkvord
Atlantic herring, Clupea harengus, have complex population structures. Mixing of populations is known, but the extent of connectivity is still unclear. Phenotypic plasticity results in divergent phenotypes in response to environmental factors. A marked salinity gradient occurs from Atlantic Ocean (salinity 35) into the Baltic Sea (salinity range 2-12). Herring from both habitats display phenotypic and genetic variability. To explore how genetic factors and salinity influence phenotypic traits like growth, number of vertebrae and otolith shape an experimental population consisting of Atlantic purebreds and Atlantic/Baltic F1 hybrids were incubated and co-reared at two different salinities, 16 and 35, for three years...
2018: PloS One
Krzysztof M Czajkowski, Anna Pastuszczak, Rafał Kotyński
Single-pixel imaging is an indirect imaging technique which utilizes simplified optical hardware and advanced computational methods. It offers novel solutions for hyper-spectral imaging, polarimetric imaging, three-dimensional imaging, holographic imaging, optical encryption and imaging through scattering media. The main limitations for its use come from relatively high measurement and reconstruction times. In this paper we propose to reduce the required signal acquisition time by using a novel sampling scheme based on a random selection of Morlet wavelets convolved with white noise...
January 11, 2018: Scientific Reports
Ashish Kumar, Rama Komaragiri, Manjeet Kumar
With the alarming rise in the deaths due to cardiovascular diseases (CVD), present medical research scenario places notable importance on techniques and methods to detect CVDs. As adduced by world health organization, technological proceeds in the field of cardiac function assessment have become the nucleus and heart of all leading research studies in CVDs in which electrocardiogram (ECG) analysis is the most functional and convenient tool used to test the range of heart-related irregularities. Most of the approaches present in the literature of ECG signal analysis consider noise removal, rhythm-based analysis, and heartbeat detection to improve the performance of a cardiac pacemaker...
January 11, 2018: Journal of Medical Systems
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