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Lin Xu, Qian Zheng, Tao Jiang
Generalized Auto-calibrating Partially Parallel Acquisitions (GRAPPA) has been widely used to reduce imaging time in Magnetic Resonance Imaging. GRAPPA synthesizes missing data by using a linear interpolation of neighboring measured data over all coils, thus accuracy of the interpolation weights fitting to the auto-calibrating signal data is crucial for the GRAPPA reconstruction. Conventional GRAPPA algorithms fitting the interpolation weights with a least squares solution are sensitive to interpolation window size...
October 10, 2018: Scientific Reports
Jingyuan Lyu, Ukash Nakarmi, Dong Liang, Jinhua Sheng, Leslie Ying
The conventional calibration-based parallel imaging method assumes a linear relationship between the acquired multi-channel k-space data and the unacquired missing data, where the linear coefficients are estimated using some auto-calibration data. In this work, we first analyze the model errors in the conventional calibration-based methods and demonstrate the nonlinear relationship. Then a much more general nonlinear framework is proposed for auto-calibrated parallel imaging. In this framework, kernel tricks are employed to represent the general nonlinear relationship between acquired and unacquired k-space data without increasing the computational complexity...
August 7, 2018: IEEE Transactions on Medical Imaging
XueJun Jin, Jinwoo Jung, Seong Young Ko, Eunpyo Choi, Jong-Oh Park, Chang-Sei Kim
A cable-driven parallel robot has benefits of wide workspace, high payload, and high dynamic response owing to its light cable actuator utilization. For wide workspace applications, in particular, the body frame becomes large to cover the wide workspace that causes robot kinematic errors resulting from geometric uncertainty. However, appropriate sensors as well as inexpensive and easy calibration methods to measure the actual robot kinematic parameters are not currently available. Hence, we present a calibration sensor device and an auto-calibration methodology for the over-constrained cable-driven parallel robots using one-dimension laser distance sensors attached to the robot end-effector, to overcome the robot geometric uncertainty and to implement precise robot control...
July 23, 2018: Sensors
Dixys L Hernández-Rojas, Tiago M Fernández-Caramés, Paula Fraga-Lamas, Carlos J Escudero
This article presents a Virtual Transducer Electronic Data Sheet (VTEDS)-based framework for the development of intelligent sensor nodes with plug-and-play capabilities in order to contribute to the evolution of the Internet of Things (IoT) toward the Web of Things (WoT). It makes use of new lightweight protocols that allow sensors to self-describe, auto-calibrate, and auto-register. Such protocols enable the development of novel IoT solutions while guaranteeing low latency, low power consumption, and the required Quality of Service (QoS)...
June 27, 2018: Sensors
Hossam A Shaltout, Sung W Lee, Catherine L Tegeler, Joshua R Hirsch, Sean L Simpson, Lee Gerdes, Charles H Tegeler
Background: Heart rate variability (HRV) is an indicator of dynamic adaptability of the autonomic nervous system. Few interventions target upstream, cerebral cortex components of the heart-brain system for autonomic management. We report changes in HRV and baroreflex sensitivity (BRS), associated with use of a noninvasive, closed-loop, allostatic, computer-guided, acoustic stimulation neurotechnology. Methods: Over 5 years, 220 subjects with heterogeneous neurological, cardiovascular, and psychophysiological conditions consecutively enrolled in a naturalistic, single-arm study exploring clinical effects associated with use of the neurotechnology...
2018: Frontiers in Public Health
Timothy McGrath, Richard Fineman, Leia Stirling
Inertial measurement units (IMUs) have been demonstrated to reliably measure human joint angles—an essential quantity in the study of biomechanics. However, most previous literature proposed IMU-based joint angle measurement systems that required manual alignment or prescribed calibration motions. This paper presents a simple, physically-intuitive method for IMU-based measurement of the knee flexion/extension angle in gait without requiring alignment or discrete calibration, based on computationally-efficient and easy-to-implement Principle Component Analysis (PCA)...
June 8, 2018: Sensors
Carlos Cambra, Sandra Sendra, Jaime Lloret, Raquel Lacuesta
Improving the sustainability in agriculture is nowadays an important challenge. The automation of irrigation processes via low-cost sensors can to spread technological advances in a sector very influenced by economical costs. This article presents an auto-calibrated pH sensor able to detect and adjust the imbalances in the pH levels of the nutrient solution used in hydroponic agriculture. The sensor is composed by a pH probe and a set of micropumps that sequentially pour the different liquid solutions to maintain the sensor calibration and the water samples from the channels that contain the nutrient solution...
April 25, 2018: Sensors
Grégoire Weil, Cyrus Motamed, Alexandre Eghiaian, Xavier Monnet, Stéphanie Suria
OBJECTIVE: To compare cardiac index (CI) between Proaqt/PulsioFlex® and oesophageal Doppler (OD) and the ability of the PulsioFlex® to track CI changes induced by fluid challenge and secondly to assess the impact of the time interval between two auto-calibrations of PulsioFlex® on the accuracy of the measured CI. METHODS: In a single hospital, 49 intermediate-risk oncologic abdominal surgery patients were included in an observational study. We measured the cardiac Index (CI) provided by OD and by the Proaqt/PulsioFlex® before and after internal calibration, which were performed randomly at specific intervals after the initial one (30, 60, 90 and 120min)...
April 18, 2018: Anaesthesia, Critical Care & Pain Medicine
Nicolas Moser, Jesus Rodriguez-Manzano, Tor Sverre Lande, Pantelis Georgiou
This paper presents a novel CMOS-based system-on-chip with a 78 56 ion-sensitive field-effect transistor array using in-pixel quantization and compensation of sensor nonidealities. The pixel integrates sensing circuitry and memory cells to encode the ion concentration in time and store a calibration value per pixel. Temperature sensing pixels spread throughout the array allow temperature monitoring during the reaction. We describe the integration of the array as part of a lab-on-chip cartridge that plugs into a motherboard for power management, biasing, data acquisition, and temperature regulation...
April 2018: IEEE Transactions on Biomedical Circuits and Systems
Wenwen Jiang, Peder E Z Larson, Michael Lustig
PURPOSE: To correct gradient timing delays in non-Cartesian MRI while simultaneously recovering corruption-free auto-calibration data for parallel imaging, without additional calibration scans. METHODS: The calibration matrix constructed from multi-channel k-space data should be inherently low-rank. This property is used to construct reconstruction kernels or sensitivity maps. Delays between the gradient hardware across different axes and RF receive chain, which are relatively benign in Cartesian MRI (excluding EPI), lead to trajectory deviations and hence data inconsistencies for non-Cartesian trajectories...
November 2018: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Catherine L Tegeler, Lee Gerdes, Hossam A Shaltout, Jared F Cook, Sean L Simpson, Sung W Lee, Charles H Tegeler
BACKGROUND: Military-related post-traumatic stress (PTS) is associated with numerous symptom clusters and diminished autonomic cardiovascular regulation. High-resolution, relational, resonance-based, electroencephalic mirroring (HIRREM®) is a noninvasive, closed-loop, allostatic, acoustic stimulation neurotechnology that produces real-time translation of dominant brain frequencies into audible tones of variable pitch and timing to support the auto-calibration of neural oscillations. We report clinical, autonomic, and functional effects after the use of HIRREM® for symptoms of military-related PTS...
December 22, 2017: Military Medical Research
Seyed Mohsen Seyed Moosavi, Bijan Moaveni, Behzad Moshiri, Mohammad Reza Arvan
The present study designed skewed redundant accelerometers for a Measurement While Drilling (MWD) tool and executed auto-calibration, fault diagnosis and isolation of accelerometers in this tool. The optimal structure includes four accelerometers was selected and designed precisely in accordance with the physical shape of the existing MWD tool. A new four-accelerometer structure was designed, implemented and installed on the current system, replacing the conventional orthogonal structure. Auto-calibration operation of skewed redundant accelerometers and all combinations of three accelerometers have been done...
February 27, 2018: Sensors
Jeremy W Gordon, Rie B Hansen, Peter J Shin, Yesu Feng, Daniel B Vigneron, Peder E Z Larson
With the translation of metabolic MRI with hyperpolarized 13 C agents into the clinic, imaging approaches will require large volumetric FOVs to support clinical applications. Parallel imaging techniques will be crucial to increasing volumetric scan coverage while minimizing RF requirements and temporal resolution. Calibrationless parallel imaging approaches are well-suited for this application because they eliminate the need to acquire coil profile maps or auto-calibration data. In this work, we explored the utility of a calibrationless parallel imaging method (SAKE) and corresponding sampling strategies to accelerate and undersample hyperpolarized 13 C data using 3D blipped EPI acquisitions and multichannel receive coils, and demonstrated its application in a human study of [1-13 C]pyruvate metabolism...
April 2018: Journal of Magnetic Resonance
Sebastian Roth, Henrik Fox, Uwe Fuchs, Uwe Schulz, Angelika Costard-Jäckle, Jan F Gummert, Dieter Horstkotte, Olaf Oldenburg, Thomas Bitter
BACKGROUND: Determination of cardiac output (CO) is essential in diagnosis and management of heart failure (HF). The gold standard to obtain CO is invasive assessment via thermodilution (TD). Noninvasive pulse contour analysis (NPCA) is supposed as a new method of CO determination. However, a validation of this method in HF is pending and performed in the present study. METHODS: Patients with chronic-stable HF and reduced left ventricular ejection fraction (LVEF ≤ 45%; HF-REF) underwent right heart catheterization including TD...
May 2018: Clinical Research in Cardiology: Official Journal of the German Cardiac Society
Shawn Chancy Countryman, Saulo Leonardo Sousa Melo, Manuella Dias Furtado Belem, Francisco Haiter-Neto, Marcos A Vargas, Veeratrishul Allareddy
OBJECTIVES: The aim of this study was to assess whether auto-calibrating medical-grade monitors perform better than off-the-shelf monitors and tablet computers in detecting artificial incipient and recurrent caries-like lesions. STUDY DESIGN: Sixty extracted teeth (30 premolars and 30 molars) were selected. All molars received class II amalgam and composite restorations. A 7-mm2 area on the crowns of half of the teeth was demineralized. Phantoms consisting of 4 teeth were created...
February 2018: Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology
Jizhong Duan, Yu Liu, Peiguang Jing
Self-consistent parallel imaging (SPIRiT) is an auto-calibrating model for the reconstruction of parallel magnetic resonance imaging, which can be formulated as a regularized SPIRiT problem. The Projection Over Convex Sets (POCS) method was used to solve the formulated regularized SPIRiT problem. However, the quality of the reconstructed image still needs to be improved. Though methods such as NonLinear Conjugate Gradients (NLCG) can achieve higher spatial resolution, these methods always demand very complex computation and converge slowly...
February 2018: Magnetic Resonance Imaging
Matthew Toews, William M Wells
This paper presents a method for automatically calibrating and assessing the calibration quality of an externally tracked 2-D ultrasound (US) probe by scanning arbitrary, natural tissues, as opposed a specialized calibration phantom as is the typical practice. A generative topic model quantifies the posterior probability of calibration parameters conditioned on local 2-D image features arising from a generic underlying substrate. Auto-calibration is achieved by identifying the maximum a-posteriori image-to-probe transform, and calibration quality is assessed online in terms of the posterior probability of the current image-to-probe transform...
January 2018: IEEE Transactions on Medical Imaging
Macauley S Breault, Adam D Costanza, Nathan A Wood, Michael J Passineau, Cameron N Riviere
Gene therapies have emerged as a promising treatment for congestive heart failure, yet they lack a method for minimally invasive, uniform delivery. To address this need we developed Cerberus, a minimally invasive parallel wire robot for cardiac interventions. Prior work on controlling the movement of Cerberus required accurate knowledge of device geometry. In order to determine the geometry of the device in vivo, this paper presents work on developing an auto-calibration procedure to measure the geometry of the robot using force sensors to move injector...
April 2015: Proceedings of the IEEE ... Annual Northeast Bioengineering Conference
Jasmine Pramila Devadhasan, Dami Kim, Do Young Lee, Sanghyo Kim
Smartphones and related accessories are rapidly expanding their applications in various fields. Herein we developed a smartphone coupled handheld array reader with the integration of complementary metal oxide (CMOS) image sensor for detecting various toxic gases by colorimetric monitoring approach. In this study, toxic gases such as hydrogen fluoride (HF), chlorine (Cl2 ), ammonia (NH3 ), and formaldehyde (CH2 O) were detected using titanium nanoparticles (TiO2 NPs) blended poly (vinyl alcohol) (PVA) hydrogel test strips, which were patterned with chemically responsive dyes...
September 1, 2017: Analytica Chimica Acta
Uddin M Jalal, Sang C Kim, Joon S Shim
A novel and rapid analysis technique using histogram has been proposed for the colorimetric quantification of blood hematocrits. A smartphone-based "Histogram" app for the detection of hematocrits has been developed integrating the smartphone embedded camera with a microfluidic chip via a custom-made optical platform. The developed histogram analysis shows its effectiveness in the automatic detection of sample channel including auto-calibration and can analyze the single-channel as well as multi-channel images...
July 1, 2017: Biomedical Optics Express
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