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Noise Cancellation

Kensuke Sekihara, Srikantan S Nagarajan
OBJECTIVE: In biomagnetic signal processing, the theory of the signal subspace has been applied to removing interfering magnetic fields, and a representative algorithm is the signal space projection algorithm, in which the signal/interference subspace is defined in the spatial domain as the span of signal/interference-source lead field vectors. This paper extends the notion of this conventional (spatial domain) signal subspace by introducing a new definition of signal subspace in the time domain...
August 18, 2017: Journal of Neural Engineering
Nabil Faranesh, Ebrahim Magamseh, Suliman Zaaroura, Reem Zeidan, Avi Shupak
OBJECTIVE: To compare the hearing and otoacoustic emissions (OAE) outcome of stapedotomy employing 0.4 and 0.6 mm diameter prostheses. MATERIALS AND METHODS: In total, 18 patients with otosclerosis participated in a prospective, double-armed, randomized cohort study. All the patients underwent small fenestra drill stapedotomy employing the Causse fluroplastic large loop piston prostheses. The patients were randomly assigned to groups of 0.4 mm (n=9) and 0.6 mm (n=9) diameter prostheses...
August 2017: Journal of International Advanced Otology
Marko Haramija, Jasna Peter-Katalinić
RATIONALE: Affinity mass spectrometry (AMS) is an emerging tool in the field of study of protein-carbohydrate complexes. However, experimental obstacles and data analysis is preventing faster integration of AMS methods in the field of glycosciences. Here we show how analysis of direct ESI-MS AMS data can be simplified for screening purposes, even for complex AMS spectra. METHODS: Direct ESI-MS assay was tested in this study, and binding data for the galectin-3C•lactose complex were analyzed using comprehensive and simplified data analysis approach...
August 14, 2017: Rapid Communications in Mass Spectrometry: RCM
Nikhil Deshpande, Jonas Braasch
This study investigates how virtual head rotations can improve a binaural model's ability to segregate speech signals. The model takes two mixed speech sources spatialized to unique azimuth positions and localizes them. The model virtually rotates its head to orient itself for the maximum signal-to-noise ratio for extracting the target. An equalization-cancellation approach is used to generate a binary mask for the target based on localization cues. The mask is then overlaid onto the mixed signal's spectrogram to extract the target from the mixture...
July 2017: Journal of the Acoustical Society of America
Evgeny Katz, Yaroslav Filipov, Sergii Domanskyi, Mackenna L Wood, Maria Gamella, Vladimir Privman
We report an experimental realization of a biochemical XOR gate function that avoids many of the pitfalls of earlier realizations based on biocatalytic cascades. Inputs - represented by pairs of chemicals - cross-react to largely cancel out when both are nearly equal. The cross-reaction can be designed to also optimize gate functioning for noise handling. When not equal, the residual inputs are further processed to result in the output of the XOR type, by biocatalytic steps that allow for further gate-function optimization...
July 26, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Genevieve Plant, Yifeng Chen, Gerard Wysocki
A proof-of-concept heterodyne-enhanced chirped laser dispersion spectroscopy system is presented. In remote sensing systems where low return powers are expected, the addition of an optical local oscillator and subsequent nonlinear processing can provide improved performance in chirped laser dispersion spectroscopy. Details about the system configuration, phase noise cancellation, and experimental verification are discussed.
July 15, 2017: Optics Letters
Jason P Stockmann, Lawrence L Wald
Functional MRI (fMRI) at 7 T and above provides improved Signal-to-Noise Ratio and Contrast-to-Noise Ratio compared to 3 T acquisitions. In addition to the beneficial effects on spin polarization and magnetization of deoxyhemoglobin, the increased applied field also further magnetizes air and tissue. While the magnets themselves typically provide a static B0 field with sufficient spatial homogeneity, the diamagnetism of tissue and the paramagnetism of air causes local field deviations inside the human head...
June 7, 2017: NeuroImage
Mutsumi Noro, Daisuke Anzai, Jianqing Wang
Wearable electrocardiogram (ECG) is attracting much attention for monitoring heart diseases in healthcare and medical applications. However, an imbalance usually exists between the contact resistances of sensing electrodes, so that a common mode noise caused by external electromagnetic field can be converted into the ECG detection circuit as a differential mode interference voltage. In this study, after explaining the mechanism of how the common mode noise is converted to a differential mode interference voltage, the authors propose a circuit with cadmium sulphide photo-resistors for cancelling the imbalance between the contact resistances and confirm its validity by simulation experiment...
April 2017: Healthcare Technology Letters
Nimrod Shaham, Yoram Burak
It has been proposed that neural noise in the cortex arises from chaotic dynamics in the balanced state: in this model of cortical dynamics, the excitatory and inhibitory inputs to each neuron approximately cancel, and activity is driven by fluctuations of the synaptic inputs around their mean. It remains unclear whether neural networks in the balanced state can perform tasks that are highly sensitive to noise, such as storage of continuous parameters in working memory, while also accounting for the irregular behavior of single neurons...
May 2017: PLoS Computational Biology
Gustavo Funes, Jaime Anguita
By means of an experimental setup, we study the time evolution of orbital angular momentum (OAM) crosstalk after a 5 m propagation path with a turbulence perturbation generated by a flat heater. This convective turbulence could simulate the beam passing over hot concrete or building roofs. We study the consequences of using a wide range of transmission OAM states. We also explore the effect of misalignment, and we propose two new different techniques for analyzing the vortex cancellation. Even though results are inconsistent with theoretical predictions, especially for low turbulence regimes, we state that signal-to-noise ratio is the key factor to understanding this discrepancy...
May 1, 2017: Optics Letters
Qiang Guo, Liangang Qi
In the coexistence of multiple types of interfering signals, the performance of interference suppression methods based on time and frequency domains is degraded seriously, and the technique using an antenna array requires a large enough size and huge hardware costs. To combat multi-type interferences better for GNSS receivers, this paper proposes a cascaded multi-type interferences mitigation method combining improved double chain quantum genetic matching pursuit (DCQGMP)-based sparse decomposition and an MPDR beamformer...
April 10, 2017: Sensors
Wootaek Lim, Taekwang Jang, Inhee Lee, Hun-Seok Kim, Dennis Sylvester, David Blaauw
We present a sub-nW optical wake-up receiver for wireless sensor nodes. The wake-up receiver supports dual mode operation for both ultra-low standby power and high data rates, while canceling ambient in-band noise. In 0.18µm CMOS the receiver consumes 380pW in always-on wake-up mode and 28.1µW in fast RX mode at 250kbps.
June 2016: Symposium on VLSI Circuits: [proceedings]. Symposium on VLSI Circuits
Zhen Qu, Ivan B Djordjevic
A high-speed four-state continuous-variable quantum key distribution (CV-QKD) system, enabled by wavelength-division multiplexing, polarization multiplexing, and orbital angular momentum (OAM) multiplexing, is studied in the presence of atmospheric turbulence. The atmospheric turbulence channel is emulated by two spatial light modulators (SLMs) on which two randomly generated azimuthal phase patterns yielding Andrews' spectrum are recorded. The phase noise is mitigated by the phase noise cancellation (PNC) stage, and channel transmittance can be monitored directly by the D...
April 3, 2017: Optics Express
Y K Chiang, Y S Choy, S K Tang
The noise attenuation of fan-ducted noise at low blade-passage frequency remains a challenge. The present study investigates the noise reduction mechanism of a tensioned membrane housing device that directly controls the sound radiation from the doublet which is enclosed in an infinitely long duct with a point vortex. The time dependent sound radiation mechanism and the vibro-acoustics coupling mechanism of the systems are studied by adopting the potential theory and matched asymptotic expansion technique. The silencing performance of such a passive approach depends on the amplitude and phase of the sound field created by the doublet and the acoustic pressure induced by the membrane oscillation in order to achieve sound cancellation...
March 2017: Journal of the Acoustical Society of America
Ping Wang, Na Li, Han-Wu Luo, Yong-Kun Zhu, Shi-Gang Cui
A modified generalized sidelobe canceller (IGSC) algorithm is proposed to enhance the resolution and robustness against the noise of the traditional generalized sidelobe canceller (GSC) and coherence factor combined method (GSC-CF). In the GSC algorithm, weighting vector is divided into adaptive and non-adaptive parts, while the non-adaptive part does not block all the desired signal. A modified steer vector of the IGSC algorithm is generated by the projection of the non-adaptive vector on the signal space constructed by the covariance matrix of received data...
March 2017: Journal of the Acoustical Society of America
Art Ambrosio, Ali N Hoffer, Michael Hoffer
OBJECTIVES: (1) To investigate whether the occlusion effect and hearing attenuation produced by 3M Combat Arms Ear Plugs (CAEP) affects balance when compared to no hearing protection and (2) to investigate whether the occlusion effect and noise-canceling capabilities of the Nacre QuietPro system affects balance when compared to no hearing protection. METHODS: This prospective study collected pilot data for investigation of mechanisms of balance. 20 subjects with normal hearing and no vestibular dysfunction were tested with blackened goggles in three conditions-no hearing protection, CAEP, and with the Nacre QuietPro...
March 2017: Military Medicine
Chenxi Yang, Negar Tavassolian
This paper presents a dual-sensor method of extracting seismocardiographic (SCG) data from moving adult subjects using chest-worn wireless MEMS accelerometers. A digital signal processing (DSP) system including a normalized least means square (NLMS) adaptive filter is designed and tested in MATLAB. Data results from 10 subjects indicate a detection rate of 98.72% which outperforms our previously-proposed single-sensor scheme. Various sensor positons and possible failure mechanisms are also investigated to further evaluate the system performance...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
Yohei Tomita
This paper addresses motion noise removal for an earbud-based reflective photoplethysmographic (PPG) sensor. This system can be worn comfortably on the ear for a long time. However, body movements such as walking and running cause signal degradation. To improve signal quality, I propose a novel asynchronous noise removal method using only the right and left PPG signals. It cancels not only uncorrelated noise components but also asynchronous noise components by simply introducing a weight function in the calculation process of a Wiener filter...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
Nadica Miljković, Nenad Popović, Olivera Djordjević, Ljubica Konstantinović, Tomislav B Šekara
BACKGROUND AND OBJECTIVE: New aspects for automatic electrocardiography artifact removal from surface electromyography signals by application of fractional order calculus in combination with linear and nonlinear moving window filters are explored. Surface electromyography recordings of skeletal trunk muscles are commonly contaminated with spike shaped artifacts. This artifact originates from electrical heart activity, recorded by electrocardiography, commonly present in the surface electromyography signals recorded in heart proximity...
March 2017: Computer Methods and Programs in Biomedicine
Nannan Zhang, Jinyong Zhang, Hui Li, Omisore Olatunji Mumini, Oluwarotimi Williams Samuel, Kamen Ivanov, Lei Wang
Non-invasive fetal electrocardiograms (FECGs) are an alternative method to standard means of fetal monitoring which permit long-term continual monitoring. However, in abdominal recording, the FECG amplitude is weak in the temporal domain and overlaps with the maternal electrocardiogram (MECG) in the spectral domain. Research in the area of non-invasive separations of FECG from abdominal electrocardiograms (AECGs) is in its infancy and several studies are currently focusing on this area. An adaptive noise canceller (ANC) is commonly used for cancelling interference in cases where the reference signal only correlates with an interference signal, and not with a signal of interest...
February 24, 2017: Sensors
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