Articles de revues : « Radiofrequency interference »

1

Follett, D. H. « Electromagnetic radiofrequency interference with Doppler equipment ». Physics in Medicine and Biology 36, n^o 11 (1 novembre 1991) : 1443–55. http://dx.doi.org/10.1088/0031-9155/36/11/004.

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Badizadegan, Nima D., Sarah Greenberg, Heather Lawrence et Kamran Badizadegan. « Radiofrequency Interference in the Clinical Laboratory ». American Journal of Clinical Pathology 151, n^o 5 (21 janvier 2019) : 522–28. http://dx.doi.org/10.1093/ajcp/aqy174.

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Sadykov, E. K., V. V. Arinin, F. G. Vagizov et O. A. Kocharovskaya. « Radiofrequency stimulated quantum interference on Mössbauer transitions ». Laser Physics 17, n^o 5 (mai 2007) : 727–33. http://dx.doi.org/10.1134/s1054660x07050209.

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Rohalin, Serhii. « METHODS OF IMPLEMENTATION OF EXPERT STUDIES OF ELECTRICITY MEASURING DEVICES EXPOSED TO THE IMPACT OF RADIO-FREQUENCY ELECTROMAGNETIC RADIATION ». Criminalistics and Forensics, n^o 67 (9 août 2022) : 493–507. http://dx.doi.org/10.33994/kndise.2022.67.50.

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Investigation of the influence of electromagnetic radiation on the operation of electronic metering devices for electricity is one of the demanded areas of forensic electrical engineering expertise. However, the scientific and practical study of this area of forensic research does not coincide with modern requirements. The study of the influence of electromagnetic radiation of the radio frequency range on the operation of electronic metering devices for electricity, as well as the identification of such radiation as accidental or intentionally created for the purpose of unaccounted consumption of electricity, are relevant. The article systematizes the requirements established by regulatory documents for the stability of the operation of metering devices for electricity when exposed to radiofrequency electromagnetic radiation. The mechanism of the influence of radiofrequency electromagnetic radiation on electric energy metering devices and the constructive elements of metering devices sensitive to the effects of such radiation is determined. A list of the necessary initial data for conducting forensic examinations on the determination of the impact of radiofrequency electromagnetic radiation on the investigated metering device and the tasks of identifying radiofrequency radiation devices as an effect is indicated. Conditions are determined under which the conclusion about interference in the operation of the metering device for the purpose of unaccounted electricity consumption may be categorical. Recommendations have been developed to determine the source of radiofrequency radiation as probable in cases where the source is not provided for instrumental research in expert proceedings to study the interference in the operation of the metering device. A methodology has been developed for conducting forensic examinations on the issues of determining the existence of the impact of radiofrequency electromagnetic radiation on the investigated metering device for the purpose of unaccounted consumption of electrical energy and the tasks of identifying radiofrequency radiation devices as sources of influence. The developed methodology is recommended for use in forensic practice according to the stages of the study, together with the provisions and generalizations set out in the article. Key words: electric energy metering device, interference in the operation of the metering device, electromagnetic radiation, radiation frequency, electric field, electric field strength, electromagnetic field, Umov-Poynting vector, radiation power, classes of electromagnetic environment.

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Carlone, M., B. Burke, M. Lamey, S. Rathee et B. Fallone. « SU-GG-J-161 : Radiofrequency Interference Between a Linac and MRI ». Medical Physics 35, n^o 6Part8 (juin 2008) : 2716. http://dx.doi.org/10.1118/1.2961710.

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Shetty, Anil N. « Suppression of radiofrequency interference in cardiac gated MRI : A simple design ». Magnetic Resonance in Medicine 8, n^o 1 (septembre 1988) : 84–88. http://dx.doi.org/10.1002/mrm.1910080110.

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Barnett, Gene H., Allan H. Ropper et Keith A. Johnson. « Physiological support and monitoring of critically ill patients during magnetic resonance imaging ». Journal of Neurosurgery 68, n^o 2 (février 1988) : 246–50. http://dx.doi.org/10.3171/jns.1988.68.2.0246.

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✓ Magnetic resonance (MR) imaging has been largely restricted to patients who are neurologically and hemodynamically stable. The strong magnetic field and radiofrequency transmissions involved in acquiring images are potential sources of interference with monitoring equipment. A method of support and physiological monitoring of critically ill neurosurgical and neurological patients during MR imaging using a 0.6-tesla MR system is reported. This technique has not caused degradation of the MR image due to electrical interference. Adequate preparation and precautions allow many critically ill neurosurgical and neurological patients to safely undergo MR imaging.

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Klein, M. J., S. Gulkis, E. T. Olsen, E. F. Armstrong et E. B. Jackson. « An assessment of the impact of radiofrequency interference on microwave SETI searches ». Acta Astronautica 26, n^o 3-4 (mars 1992) : 227–32. http://dx.doi.org/10.1016/0094-5765(92)90102-o.

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Chung, Soon Cheol, Jeong Han Yi, Gye Rae Tack, Bong Soo Lee, Ji Hun Kwon, Sin Kim et Jin Hun Sohn. « Development of an MR-Compatible ECG Amplifier ». Key Engineering Materials 321-323 (octobre 2006) : 1032–35. http://dx.doi.org/10.4028/www.scientific.net/kem.321-323.1032.

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The purpose of the present study is to develop a magnetic resonance (MR)-compatible electrocardiogram (ECG) amplifier. If ECG signals are measured simultaneously with the acquisition of MR images, there can be a mutual interference effect. The present system was designed to block noises caused by the main magnetic field, gradient magnetic field and radiofrequency (RF) pulse when MR images are acquired. It uses analogue elements in order to remove any possible effect on MR images. In addition, a radio-frequency-interference (RFI)-free optical data link using the pulse-width modulation (PWM) technique is adopted in order to transmit ECG signals measured inside the MR room.

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Barbieri, Massimo, et Martina Bellini. « Radiofrequency neurotomy for the treatment of chronic pain : interference with implantable medical devices ». Anestezjologia Intensywna Terapia 46, n^o 3 (31 juillet 2014) : 162–65. http://dx.doi.org/10.5603/ait.2014.0029.

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Yamamoto, Seiichi. « Effective Radiofrequency Attenuation Methods to Reduce the Interference Between PET and MRI Systems ». IEEE Transactions on Radiation and Plasma Medical Sciences 1, n^o 5 (septembre 2017) : 400–404. http://dx.doi.org/10.1109/trpms.2017.2729620.

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Donato, Mariana, João Pimentel, Rui Cabral et Pedro Escada. « Radiofrequency for Treatment of Refractory Epistaxis in Hereditary Hemorrhagic Telangiectasia ». Acta Médica Portuguesa 31, n^o 1 (31 janvier 2018) : 63. http://dx.doi.org/10.20344/amp.8802.

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Hereditary hemorrhagic telangiectasia is a rare multi-systemic autosomal dominant disorder characterized by dysplasia of the vascular connective tissue and recurrent bleeding tendency. Epistaxis is the most common and earliest symptom. It is usually mild to moderate, however, in some patients it can be severe with significant interference in quality of life. We report a case of a patient with hereditary hemorrhagic telangiectasia, in which an episode of refractory epistaxis was treated with radiofrequency and fibrin sealant. Control of acute bleeding and elimination of telangiectasia was possible with this technique. After six months follow-up, there was no epistaxis recurrence. Various treatments for epistaxis in this disease have been described in the literature, but there is no consensus about the gold-standard procedure. Radiofrequency ablation of telangiectasia is a recent technique that has shown to be safe, effective and well tolerated, even in patients who underwent other previous treatments.

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Mahdi, Basheer Muslih, et Essa Ibrahim Essa. « A Free Space Optic/Optical Wireless Communication : A Survey ». Journal of Robotics and Control (JRC) 3, n^o 3 (1 mai 2022) : 386–94. http://dx.doi.org/10.18196/jrc.v3i3.14590.

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The exponential demand for the next generation of services over free space optic and wireless optic communication is a necessity to approve new guidelines in this range. In this review article, we bring together an earlier study associated with these schemes to help us implement a multiple input/multiple output flexible platform for the next generation in an efficient manner. OWC/FSO is a complement clarification to radiofrequency technologies. Notably, they are providing various gains such as unrestricted authorizing, varied volume, essential safekeeping, and immunity to interference.

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Yu, Siegrid S., Whitney D. Tope et Roy C. Grekin. « Cardiac Devices and Electromagnetic Interference Revisited : New Radiofrequency Technologies and Implications for Dermatologic Surgery ». Dermatologic Surgery 31, n^o 8 (21 mars 2006) : 932–40. http://dx.doi.org/10.1111/j.1524-4725.2005.31808.

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MAN, K. CHING, THERESA DAVIDSON, JONATHAN J. LANGBERG, FRED MORADY et STEVEN J. KALBFLEISGH. « Interference From a Hand Held Radiofrequency Remote Control Causing Discharge of an Implantahle Defibrillator ». Pacing and Clinical Electrophysiology 16, n^o 8 (août 1993) : 1756–58. http://dx.doi.org/10.1111/j.1540-8159.1993.tb01049.x.

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Zhu, Wanshan, Zhe Gao, Zhuo Meng, Chen Wang, Yang Li, Chunmei Wang et Yunwei Jia. « Research and Design of Radiofrequency Antenna on LCD ». International Journal of Antennas and Propagation 2022 (30 mai 2022) : 1–7. http://dx.doi.org/10.1155/2022/5320561.

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This work studies the electromagnetic field of a radiofrequency (RF) antenna on 7-inch liquid crystal display (LCD) and presents a new approach where the RF antenna is designed on LCD. This approach takes the magnetic field effect of LCD as an input parameter when building and simulating antenna models using the software Ansoft HFSS. After obtaining the PCB of the antenna, place the antenna on LCD, so that the antenna and LCD overlap up and down and measure the equivalent physical parameters as a whole. Last, use the vector network analyzer and Smith circle graph to tune the antenna system for completing the impedance matching of the whole system. This method breaks through the limitation that the card swiping area and the display area cannot be in the same area due to electromagnetic interference. It has changed the appearance design concept of the mobile point of sale (POS), and the antenna size can be 20%–100% of the POS display area. A contactless card read-write experiment for the proposed method has been carried out. Results showed the return loss is less than −30 dB, and the effective read-write distance of the antenna can reach about 5 cm. This design method provides a broader application prospect for mobile POS.

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Bautista, Alexander. « Bipolar Radiofrequency Neurotomy to Treat Neck and Back Pain in Patients with Automatic Implantable Cardioverter Defibrillator ». March 2016 3;19, n^o 3;3 (14 mars 2016) : E505—E509. http://dx.doi.org/10.36076/ppj/2019.19.e505.

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We report 2 cases of successful treatment of neck and back pain with bipolar radiofrequency ablation (RFA) of the cervical and lumbar facet joints in patients with an automatic implantable cardioverter defibrillator (AICD). Two patients with complex cardiac histories and AICD devices were treated with bipolar RFA of the facet joints. One presented with axial neck pain and the other with axial back pain. The histories and physical examinations were consistent with facetogenic pain. Diagnostic medial branch block resulted in more than 70% pain relief lasting for several days, allowing patients to perform routine daily activities without significant pain. However, we were concerned about the use of conventional RFA of the medial branches of nerves for the fear of interference with the function of AICD by the RF currents and energy. We took advantage of the localized and limited current of bipolar RFA to perform this procedure for the cervical or lumbar facet joints avoiding any interference with the function of AICD. The procedures provided long-term pain relief to the patients, and marked improvement in their functional status without any evident complications related to the function of their AICD. This case report describes the safe and successful completion of bipolar RFA of the medial branch nerves to treat cervical and lumbar facetogenic pain in patients with AICD. This modality of treatment may be considered in patients with AICD. We are finding it to be increasingly common that patients who present with chronic neck and back pain have AICDs in place. Key words: Back pain, neck pain, facet, AICD, radiofrequency neurotomy, bipolar lesioning

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VAN EESTER, DIRK. « Evaluating the efficiency of radiofrequency heating in tokamaks : the impact of orbital topology and poloidal inhomogeneity ». Journal of Plasma Physics 65, n^o 5 (juin 2001) : 407–52. http://dx.doi.org/10.1017/s0022377801001246.

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Radiofrequency heating in toroidal geometry is described. Starting from a general theory, expressions for the dielectric response and the radiofrequency diffusion operator are obtained. The computationally most efficient simplified expressions bear a close resemblance to the results of uniform plasma theory, but differ from them in their interpretation. In cases where the simplified expressions do not describe the physics faithfully, more general but computationally slower ones are available. Rigorously accounting for the geometry and the wave field yields fine structure that is commonly overlooked. Aside from causing the well-known k∥-upshift or downshift impacting on the Doppler shift, the non-zero poloidal magnetic field modifies the orbital topology and forces one to account for the poloidal inhomogeneity of the static magnetic field. The expressions obtained restore intuition on how an electric field interacts with a charged particle, but, in so doing, cast doubt on the degree of realism of predictions of simplified models that do not account for the constructive or destructive interference phenomena introduced by the orbital topology non-uniformity. The expressions represent a numerical challenge, but show the necessity for the detailed description: the ‘coarse-graining’ underlying simplified models yields a result that has the right order of magnitude for interference related to crosstalk between resonances or multiple encounters with a given resonance, but may be an order of magnitude wrong for predictions on the combined effect of a poloidal mode spectrum. A Fokker–Planck code BATCH (Bounce-Averaged Tool for Cyclotron Heating), relying on the expressions obtained, is presented and some results are discussed.

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Thanos, L., S. Mylona, P. Galani, D. Tzavoulis, V. Kalioras, S. Tanteles et M. Pomoni. « Radiofrequency ablation of osseous metastases for the palliation of pain ». Skeletal Radiology 37, n^o 3 (mars 2008) : 189–94. http://dx.doi.org/10.1007/s00256-007-0404-5.

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Abstract A number of different methods have been proposed for pain relief in cancer patients with bone metastases, each with different indications, contraindications and complications (systemic analgesics, bisphosphonates, antitumor chemotherapy, radiotherapy, systemic radio-isotopes, local surgery and vertebroplasty). The ideal treatment has to be fast, safe, effective and tolerable for the patient. CT-guided radiofrequency (RF) ablation may fulfill these criteria. Our experience in the treatment of 30 patients (34 lesions) with painful bone metastases using RF ablation was assessed. There was a significant decrease in the mean past-24-h Brief Pain Inventory (BPI) score for worst pain, for average pain and for pain interference during daily life (4.7, 4.8 and 5.3 units respectively) 4 and 8 weeks after treatment. There was a marked decrease (3 out of 30 patients 4 and 8 weeks after treatment) in the use of analgesics. CT-guided RF ablation appears to be effective for treatment of painful bone metastases.

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LASSER, ALAN E. « Letter : Cardiac Devices and Electromagnetic Interference Revisited : New Radiofrequency Technologies and Implications for Dermatologic Surgery ». Dermatologic Surgery 32, n^o 4 (avril 2006) : 598. http://dx.doi.org/10.1111/j.1524-4725.2006.32123.x.

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Sainuddin, Nurulidayu, Juwita Mohd Sultan, Fakrulradzi Idris et Mohd Azuani. « Data Collision and Interference Minimization in Wireless Sensor Network using Node Data Addressing with Random Access Time ». Jurnal Kejuruteraan 33, n^o 4 (30 novembre 2021) : 1105–12. http://dx.doi.org/10.17576/jkukm-2021-33(4)-33.

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A wireless sensor network (WSN) refers to a spatially dispersed network of sensors that monitor and collect environmental data and forward the collected data to the central station. WSN has been widely used in daily life and industrial applications, ranging from surveillance, military, healthcare, habitat monitoring, and agriculture application. However, WSN that uses radiofrequency (RF) communication may suffer from noise and interference caused by two or more radios that uses the same frequency. Data collision is also expected within the wireless network especially when numerous sensor nodes are transmitting their data to the base station (BS) through a shared medium. Hence, this research contributes in mitigating the RF interference and data collision in the network to increase the network’s data reliability by using the concept of Time Division Multiple Access (TDMA) protocol where each sensor node will be transmitting their data at a different time to avoid collision and interference in the shared medium. However, in this research, each sensor node will access the channel or the transmission medium at a random time. To prove the concept of the proposed method on data collision and interference minimization, an Internet of Things (IoT) based wireless sensor network for alerting application will be designed and implemented in the fire station. It has been found from the experimental result that RF interference and data reliability in the network can be reduced by 90% with the proposed algorithm by allowing the sensor node to access the RF channel and transmit the data at a random time.

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Drexler, Petr, Martin Čáp, Pavel Fiala, Miloslav Steinbauer, Radim Kadlec, Miloš Kaška et Lubomír Kočiš. « A Sensor System for Detecting and Localizing Partial Discharges in Power Transformers with Improved Immunity to Interferences ». Sensors 19, n^o 4 (22 février 2019) : 923. http://dx.doi.org/10.3390/s19040923.

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The paper reports on the solution, principles, and application results related to a system for diagnosing main transformers in power plants via the radiofrequency method. The subject of the diagnostics is the occurrence of partial discharge activity in transformers. The technical solution of the system is characterized in the introductory section of the article. There then follows a description of the operating principle and the implemented novel advanced methods for signal detection and source localization. The results obtained from practical application of the system within the diagnostics of high-power transformers are presented as well. Because ambient electromagnetic disturbance was recognized as a major issue during the system development, novel detection methods were proposed, implemented, and verified. The principal approach utilizes an external radiofrequency sensor to detect outer impulse disturbance and to eliminate disturbance-triggered acquisitions, and it also ensures direct real-time visualization of the desired impulse signals. The ability of weak signal detection was verified via artificial impulse signal injection into the transformer. The developed detection methods were completed with localization techniques for signal source estimation. The desired impulse signal was detected and localized during full operation of the main transformer, despite the presence of strong electromagnetic interference.

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Caputo, P., J. Tomes, J. Oppenländer, Ch Häussler, A. Friesch, T. Träuble et N. Schopohl. « Two-Tone Response of Radiofrequency Signals Using the Voltage Output of a Superconducting Quantum Interference Filter ». Journal of Superconductivity and Novel Magnetism 20, n^o 1 (17 janvier 2007) : 25–30. http://dx.doi.org/10.1007/s10948-006-0194-3.

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Raimundo-Neto, E., J. R. G. da Rosa, M. A. F. Casaroli, I. Feliciano da Costa, A. M. Alberti et Arismar Cerqueira Sodré. « Implementation of an Optical-Wireless Network with Spectrum Sensing and Dynamic Resource Allocation Using Optically Controlled Reconfigurable Antennas ». International Journal of Antennas and Propagation 2014 (2014) : 1–11. http://dx.doi.org/10.1155/2014/670930.

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This work proposes the concept and reports the implementation of an adaptive and cognitive radio over fiber architecture. It is aimed at dealing with the new demands for convergent networks by means of simultaneously providing the functionalities of multiband radiofrequency spectrum sensing, dynamic resource allocation, and centralized processing capability, as well as the use of optically controlled reconfigurable antennas and radio over fiber technology. The performance of this novel and innovative architecture has been evaluated in a geographically distributed optical-wireless network under real conditions and for different fiber lengths. Experimental results demonstrate reach extension of more than 40 times and an enhancement of more than 30 dB in the carrier to interference plus noise ratio parameter.

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Jiang, Yuan-Xi, Zhi-Yu Dong, Jun-Wen Wang, Ying Chen, Hui-Hui Sun et Shu-Chang Xu. « Efficacy of Endoscopic Radiofrequency Ablation for Treatment of Reflux Hypersensitivity : A Study Based on Rome IV Criteria ». Gastroenterology Research and Practice 2022 (27 mars 2022) : 1–8. http://dx.doi.org/10.1155/2022/4145810.

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Objective. Effective therapies for reflux hypersensitivity are lacking. Endoscopic radiofrequency ablation may reduce the sensitivity of the distal esophagus through direct interference with nociceptors or vagal afferent fibers and thus may be useful in reflux hypersensitivity. The aim of this study is to assess the effectiveness and possible mechanisms of endoscopic radiofrequency ablation in reflux hypersensitivity patients. Methods. Patients with reflux hypersensitivity who fulfilled the Rome IV criteria and who wished to receive further treatment were recruited. Endoscopic radiofrequency ablation was delivered to the gastroesophageal junction. Data were collected by questionnaire using a 6-point Likert scale. The primary outcome measure was effect on symptoms including heartburn, regurgitation, and chest pain. The secondary outcomes were degree of satisfaction, medication use, acid exposure time (AET), low esophageal sphincter (LES) pressure, and total reflux episodes. We also assessed positive cell density of transient receptor potential vanilloid type 1 receptor (TRPV1) and calcitonin gene-related peptide (CGRP), both of which are biomarkers of afferent fibers, in biopsies obtained from esophageal mucosa 0.5 cm-1 cm above the Z line. These scales will be administered at baseline, 3-month follow-up, 6-month follow-up, and 12-month follow-up. Results. A total of 22 reflux hypersensitivity patients were enrolled (14 males, median age 50.0 years). A significant improvement in symptom scores (heartburn, regurgitation, and chest pain) was noted at 3 months, 6 months, and 12 months ( P < 0.001 ). Satisfaction with life increased to 72.7% (16/22), 72.7% (16/22), and 68.2% (15/22) at 3, 6, and 12 mo, respectively, compared with baseline ( P < 0.001 ). Nineteen patients reduced their medication use after treatment. Of these, 22.7% (5/22), 31.8% (7/22), and 40.9% (9/22) subjects stopped medication use at 3 mo, 6 mo, and 12 mo, respectively. No statistical differences were noted in AET, LES pressure, or total reflux episodes from preoperation to 12 mo postoperation. After treatment, the positive cell density of both TRPV1 and CGRP decreased significantly; however, only TRPV1 had a positive correlation with heartburn ( r = 0.51 , P = 0.03 ) and chest pain ( r = 0.77 , P < 0.01 ). Conclusion. Endoscopic radiofrequency ablation was an effective and safe therapeutic option in reflux hypersensitivity patients. Further studies with large sample size are required to validate the role of radiofrequency in reflux hypersensitivity.

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Wang, X., W. Yu, Y. Deng, X. Qi et Y. Liu. « Radiofrequency interference suppression in synthetic aperture radar based on singular spectrum analysis with extended – FAPI subspace tracking ». IET Radar, Sonar & ; Navigation 6, n^o 9 (1 décembre 2012) : 881–90. http://dx.doi.org/10.1049/iet-rsn.2011.0337.

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Et. al., Kiranmai Babburu ,. « PAPR REDUCTION TECHNIQUES AND IMAGE QUALITY ASSESSMENTIN IMAGE BASED MMS VLC SYSTEM ». INFORMATION TECHNOLOGY IN INDUSTRY 9, n^o 2 (13 avril 2021) : 1178–85. http://dx.doi.org/10.17762/itii.v9i2.469.

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The radiofrequency method of transmission suffers from the problem of the limited licensed radio frequency spectrum, & security, wide EMI (electromagnetic interference), high multipath fading & power consumption for short-range applications. The solution to these problems can be achieved by using optical wireless communication technique called the Visible Light Communication system where the data is sent through regulated emission of light. The transmission of digital image information productively in the present optical wireless communication framework is an uphill task as these systems often suffer from problems like frequency selective fading propagation losses and inter-symbol interferences. In order to conquer such difficulties we hereby propose a robust method to transfer the digital image through a Multi-Carrier Modulation Scheme-MMS. In this paper, an Image-Based Multicarrier modulation VLC system is designed through which is sent a corrupted Digital Image with additive white Gaussian noise and explored the overall execution of the Image based Multicarrier modulation VLC system at distinct SNR values. The paper also addresses the issue of high Peak to Average Power Ratio (PAPR) in Multicarrier modulation and reduced it by using different PAPR reduction techniques. The received image quality of the proposed system is obtained under different signal to noise ratios at different modulation schemes..

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Haefner, Joseph W., Christopher T. Middlebrook, Alexander L. Adams, Charles F. Middleton et J. Richard Desalvo. « Tunable microwave photonic transversal filter ». International Journal of Microwave and Wireless Technologies 8, n^o 2 (16 avril 2015) : 205–13. http://dx.doi.org/10.1017/s1759078715000215.

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We present a tapped tunable delay line filter for radiofrequency (RF) photonic filtering applications, capable of rapid tunability over a wide RF bandwidth limited only by the optical components’ losses, while maintaining independence from polarization state. Multiple fiber taps with contrasting dispersion slopes are used in intensity-modulated direct detection microwave photonic links. A temporal delay is generated between the signals within each arm of the link. Once a signal is received using balanced differential detection, nulls are generated as a function of the laser's operating wavelength. Tuning of the laser allows for a rapid shifting of the nulls in the RF spectrum to dynamically mitigate co-site interference. Through this method we demonstrate the potential for rapid tunability over the RF spectrum by the variation of the operating wavelength of the optical carrier.

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Jalouli, Alireza, Saurabh Khuje, Aaron Sheng, Abdullah Islam, Massimigliano Di Luigi, Donald Petit, Zheng Li et al. « Flexible Copper–Graphene Nanoplates on Ceramic Supports for Radiofrequency Electronics with Electromagnetic Interference Shielding and Thermal Management Capacity ». ACS Applied Nano Materials 4, n^o 11 (21 octobre 2021) : 11841–48. http://dx.doi.org/10.1021/acsanm.1c02415.

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Yamashita, Kazuhiko, Kaori Kusuda, Yoshitomo Ito, Masaru Komino, Kiyohito Tanaka, Satoru Kurokawa, Michitaka Ameya et al. « Evaluation of Surgical Instruments With Radiofrequency Identification Tags in the Operating Room ». Surgical Innovation 25, n^o 4 (2 mai 2018) : 374–79. http://dx.doi.org/10.1177/1553350618772771.

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Background. Surgical instrument retention and instrument breakage compromise surgery quality and lead to medical malpractice. We developed an instrument tracking system that could alert surgeons to instrument retention during surgery and monitor instrument use to reduce the risk of breakage. Methods. This prospective, experimental clinical trial included 15 patients undergoing inguinal hernia surgery or lumpectomy under general anesthesia at Saiseikai Kurihashi Hospital. Radiofrequency identification (RFID)-tagged surgical instruments were used, and a detection antenna was placed on a mayo stand during the operation. We analyzed the 1-loop detection ratio (OLDR)—that is, the capability of the antenna to detect devices in a single reading—and the total detection rate (TDR)—that is, the data accumulated for the duration of the operation—of the RFID-tagged instruments. Results. Data analysis revealed that the OLDR was 95% accurate, whereas the TDR was 100% accurate. The antenna could not detect the RFID tag when there was interference from electrocautery noise radiation, and 6% of instrument movement was undetected by the antenna; however, the TDR and instrument use were detected at all times. Conclusions. Surgical instruments can be tracked during surgery, and this tracking can clarify the usage rate of each instrument and serve as a backup method of instrument counting. However, this study was conducted on a small scale, and RFID tags cannot be attached to small surgical instruments used in complex operations such as neurosurgery. Further efforts to develop a tracking system for these instruments are warranted.

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Ferguson, Dale C., Phil Perillat et Boris Vayner. « Spectral Characteristics of GEO Satellite Arcing – 300 To 350 MHz ». Journal of the Astronautical Sciences 69, n^o 1 (25 janvier 2022) : 139–48. http://dx.doi.org/10.1007/s40295-021-00295-8.

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AbstractIn a series of previous papers, the detection of arcing on GPS, Van Allen Probe, and GEO satellites with the Arecibo Observatory Wm. E. Gordon 305 m radiotelescope has been reported and elaborated. In this paper, characteristics of the radiofrequency spectra of two true GEO satellites are reported as they were measured with the Arecibo Mock spectrometer every 9.6 microseconds, and are contrasted with spectra of impulsive RFI (RadioFrequency Interference) events. It is shown that the arc spectra in the 300–350 MHz range are not continuous, but consist of a number of narrow spectral lines. These lines are consistent within the duration of single arcs, but change between arcs, so that when averaged over many arcs, the appearance of a continuous spectrum is approximated. This behavior is replicated in the laboratory within charging-induced vacuum arcing on small solar array samples. In contrast, the spectrum of impulsive RFI (including, but not limited to lightning strokes) is essentially random from one 9.6 microsecond sampling interval to the next. Since the spectrum of a true arc changes little throughout many samples, it cannot be due to the risetime of the arc current, which is much less than one sampling interval. Furthermore, in laboratory experiments done at very high time resolution (< 1 ns), there is little correlation between the arc current spectra and the arcing RFI spectra, indicating that even arc current fluctuations within each arc can have little to do with the UHF spectra observed.

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Gil, I., et R. Fernández-García. « Differential- and common-mode radiofrequency interference filters based on complementary split ring resonators : a conduction and radiation impact analysis ». Journal of Electromagnetic Waves and Applications 29, n^o 2 (8 janvier 2015) : 233–46. http://dx.doi.org/10.1080/09205071.2014.997372.

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Nour-Eldin, N. A., N. N. Naguib et T. J. Vogl. « Abstract No. 28 : CT volumetric assessment of the pulmonary neoplasms following radiofrequency ablation : When to consider a second interference ? » Journal of Vascular and Interventional Radiology 21, n^o 2 (février 2010) : S13. http://dx.doi.org/10.1016/j.jvir.2009.12.171.

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Mitschang, L., J. Keeler, A. L. Davis et H. Oschkinat. « Removal of zero-quantum interference in NOESY spectra of proteins by utilizing the natural inhomogeneity of the radiofrequency field ». Journal of Biomolecular NMR 2, n^o 6 (novembre 1992) : 545–56. http://dx.doi.org/10.1007/bf02192844.

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Yang, Shengying, Huibin Qin, Xiaolin Liang et Thomas Gulliver. « An Improved Unauthorized Unmanned Aerial Vehicle Detection Algorithm Using Radiofrequency-Based Statistical Fingerprint Analysis ». Sensors 19, n^o 2 (11 janvier 2019) : 274. http://dx.doi.org/10.3390/s19020274.

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Unmanned aerial vehicles (UAVs) are now readily available worldwide and users can easily fly them remotely using smart controllers. This has created the problem of keeping unauthorized UAVs away from private or sensitive areas where they can be a personal or public threat. This paper proposes an improved radio frequency (RF)-based method to detect UAVs. The clutter (interference) is eliminated using a background filtering method. Then singular value decomposition (SVD) and average filtering are used to reduce the noise and improve the signal to noise ratio (SNR). Spectrum accumulation (SA) and statistical fingerprint analysis (SFA) are employed to provide two frequency estimates. These estimates are used to determine if a UAV is present in the detection environment. The data size is reduced using a region of interest (ROI), and this improves the system efficiency and improves azimuth estimation accuracy. Detection results are obtained using real UAV RF signals obtained experimentally which show that the proposed method is more effective than other well-known detection algorithms. The recognition rate with this method is close to 100% within a distance of 2.4 km and greater than 90% within a distance of 3 km. Further, multiple UAVs can be detected accurately using the proposed method.

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Ota, Takeyoshi, Amir Degani, Brett Zubiate, Alon Wolf, Howie Choset, David Schwartzman et Marco A. Zenati. « Epicardial Atrial Ablation Using a Novel Articulated Robotic Medical Probe via a Percutaneous Subxiphoid Approach ». Innovations : Technology and Techniques in Cardiothoracic and Vascular Surgery 1, n^o 6 (décembre 2006) : 335–40. http://dx.doi.org/10.1097/imi.0b013e31802f43b1.

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Objective Minimally invasive epicardial atrial ablation to cure atrial fibrillation through the use of a percutaneous subxiphoid approach currently has a lack of dedicated technology for intrapericardial navigation around the beating heart. We have developed a novel articulated robotic medical probe and performed preliminary experiments in a porcine preparation. Methods In five large, healthy pigs, the teleoperated robotic system was introduced inside the pericardial space through a percutaneous subxiphoid approach. Secondary visualization of the left atrium and left atrial appendage was achieved with the use of a 5-mm scope inserted through a left thoracic port. The operator actively controlled the path of the robot by using a master manipulator. The catheter, with an irrigated radiofrequency tip, was guided through the working port of the robot to achieve epicardial ablation of the left atrium. Results Access to the pericardial space and progression around the left atrium was successful in all cases, with no interference with the beating heart such as a fatal arrhythmia, unexpected bleeding, and hypotension. Epicardial ablation was successfully performed in all five cases. No adverse hemodynamic or electrophysiological events were noted during the trials. When the animals were killed, there was no visually detected injury on the surrounding mediastinal structures caused by ablation. Transmural ablation was confirmed by histopathology of the left atrium. Conclusions We have developed a dedicated articulated robotic medical probe and successfully performed epicardial left atrial radiofrequency ablation. Based on the feedback from these preliminary experiments, the radius of curvature and proper visualization of the device are being improved in the next generation prototype.

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Seidman, Seth J., Randall Brockman, Brian Marc Lewis, Joshua Guag, Mitchell J. Shein, Wesley J. Clement, James Kippola, Dennis Digby, Catherine Barber et Dan Huntwork. « In vitro tests reveal sample radiofrequency identification readers inducing clinically significant electromagnetic interference to implantable pacemakers and implantable cardioverter-defibrillators ». Heart Rhythm 7, n^o 1 (janvier 2010) : 99–107. http://dx.doi.org/10.1016/j.hrthm.2009.09.071.

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Aggarwal, Geetika, Xuewu Dai, Reza Saatchi, Richard Binns et Ajay Sikandar. « Experimental Demonstration of Single-Channel EEG Signal Using 32 × 32 Pixel OLED Screen and Camera ». Electronics 8, n^o 7 (28 juin 2019) : 734. http://dx.doi.org/10.3390/electronics8070734.

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Currently, the radiofrequency (RF)-based wireless technology deployed in electroencephalography (EEG) to diagnose brain diseases suffers from frequency spectrum and electromagnetic interference, and might also have adverse effects on the health of patients and equipment used in hospitals, especially in RF-restricted zones like intensive care units (ICUs). Optical wireless communication (OWC), specifically visible light communication (VLC), is featured in 5G network to complement the radiofrequency (RF) technologies due to the fact that huge unlicensed bandwidth and available infrastructure, both indoor and outdoor, reduces the implementation cost. The conventional VLC systems deploy photodiodes as receivers, requiring hardware and infrastructure modifications in addition to smaller field of view (FOV), but the use of cameras reduce the infrastructure cost due to inbuilt filters and a wider FOV coverage gives the ability to scale a larger area. The wider FOV and the movement of camera rotation, without any additional adjustments to maintain the line-of-sight (LOS), allows the patient to be anywhere within the room and FOV. This paper demonstrates a novel healthcare system for EEG using visible light optical camera communication (VL-OCC), where a 32 × 32 pixel OLED screen acts as transmitter and the receiver section consists of several different cameras such as digital single-lens reflex camera (DLSR), android smartphone, and Thorlabs camera. The experiments were performed in LOS deploying on-off keying (OOK) modulation at several distant measurements to determine the system reliability and stability through bit error rate (BER) performance. The proposed system results depict that the DSLR camera outperforms the smartphone and Thorlabs cameras, as it is capable of transmitting an error free bit rate of 2.8 kbps at 30 fps up to 5.5 m.

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Plakke, Michael J., Yasmin Maisonave et Sean M. Daley. « Radiofrequency Scanning for Retained Surgical Items Can Cause Electromagnetic Interference and Pacing Inhibition if an Asynchronous Pacing Mode Is Not Applied ». A & ; A Case Reports 6, n^o 6 (mars 2016) : 143–45. http://dx.doi.org/10.1213/xaa.0000000000000229.

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Yang, Weicai, Qing Chang, Allison Kealy, Yong Xu et Tianyi Lan. « A Novel Location-Awareness Method Using CubeSats for Locating the Spot Beam Emitters of Geostationary Communications Satellites ». Mathematical Problems in Engineering 2018 (2018) : 1–9. http://dx.doi.org/10.1155/2018/8035093.

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As more spacecraft are launched into the Geostationary Earth Orbit (GEO) belt, the possibility of fatal collisions or unnecessary interference between spacecraft increases. In this paper, a new location-awareness method that uses CubeSats is proposed to assist with radiofrequency (RF) domain verification by means of awareness and identification of the positions of the spot beam emitters of communications satellites in geostationary orbit. By flying a CubeSat (or a constellation of CubeSats) through the coverage area of a spot beam, the spot beam emitter’s position is identified and the spot beam’s pattern knowledge is characterized. The geometry, the equations of motion of the spacecraft, the measurement process, and the filtering equations in a location system are addressed with respect to the location methods investigated in this study. A realistic scenario in which a CubeSat receives signals from GEO communications satellites is simulated using the Systems Tool Kit (STK). The results of the simulation and the analysis presented in this study provide a thorough verification of the performance of the location-awareness method.

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Mahmoudi, Golshan, Ali Hosseinzadeh, Leila Hojaji-Najafabadi et Milad Baradaran-Ghahfarokhi. « Cell Counter can be Interfered by Mobile Phone Radiofrequency Radiation : A Report and Short Review of the Recent Patents in Electromagnetic Interference ». Recent Patents on Biomarkers 4, n^o 3 (13 février 2015) : 173–79. http://dx.doi.org/10.2174/2210309005666150123225729.

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Fadila, Juniardi Nur. « Improving UAV Radio Control System with 433 MHz Radio Wave Using Lo-Ra based on QCZEK Model Communication System ». MATICS 14, n^o 1 (15 mars 2022) : 27–34. http://dx.doi.org/10.18860/mat.v14i1.16370.

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UAV must have a reliable control system considering the UAV is an unmanned vehicle that relies on human control on the ground. Most of control system used in UAVs uses a 2.4 GHz as it frequency. This frequency has disadvantaged for UAV because it is mainly used for Wi-Fi communication system so when users of UAV’s fly in urban areas where full of Wi-Fi system, there will be interference within UAV control system and Wi-Fi, so failsafe will often occur. From the theory, different frequencies produce different criteria for radiofrequency communication system to synchronize and manage and secure communication between transmitter and receiver. In this study, we will discuss the application of 433 MHz frequency for the control system for UAV. The goal of this research is to establish a reliable control system of UAV when used for the long-range mission. To make this control system, we use the Lo-Ra module with STM32 based Microcontroller designed for QCZEK TX/RX model communication. After several testing on the ground and the air, the purpose system serve 14 % longer distance than TBS system or market build system and 6 times longer distances than 2.4Ghz frequencies.

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Antayhua, Roddy A. R., Maicon D. Pereira, Nestor C. Fernandes et Fernando Rangel de Sousa. « Exploiting the RSSI Long-Term Data of a WSN for the RF Channel Modeling in EPS Environments ». Sensors 20, n^o 11 (29 mai 2020) : 3076. http://dx.doi.org/10.3390/s20113076.

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In this paper, we propose a methodology to use the received signal strength indicator (RSSI) available by the protocol stack of an installed Wireless Sensor Network (WSN) at an electric-power-system environment (EPS) as a tool for obtaining the characteristic of its communication channel. Thereby, it is possible to optimize the settings and configuration of the network after its deployment, which is usually run empirically without any previous knowledge of the channel. A study case of a hydroelectric power plant is presented, where measurements recorded over a two-month period were analyzed and treated to obtain the large-scale characteristics of the radiofrequency channel at 2.4 GHz. In addition, we showed that instantaneous RSSI data can also be used to detect specific issues in the network, such as repetitive patterns in the transmitted power level of the nodes, and information about its environment, such as the presence of external sources of electromagnetic interference. As a result, we demonstrate the practical use of the RSSI long-term data generated by the WSN for its own performance optimization and the detection of particular events in an EPS or any similar industrial environment.

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Hervis Santana, Yosvany, David Plets, Rodney Martinez Alonso, Glauco A. Guillen Nieto, Nasiel Garcia Fernandez, Margot Deruyck et Wout Joseph. « Tool for Recovering after Meteorological Events Using a Real-Time REM and IoT Management Platform ». Wireless Communications and Mobile Computing 2019 (9 juillet 2019) : 1–13. http://dx.doi.org/10.1155/2019/9767404.

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This paper is the design of a Radio Environment Map (REM) with a real-time tool to sense the radiofrequency spectrum and optimally places with Surrogate Modelling and Sequential Experimental Design tools a total of 72 SDR sensors in the selected area, using LoRa and/or NB-IoT technologies for networking. It permits the regulatory body to check the correct use of the assigned spectrum and constitutes a communication alternative in case of a catastrophic event, such as a hurricane or an earthquake, where radio and TV broadcasting play an important role in keeping people informed after such meteorological event. The radiobroadcast services use large antennas and high towers, making them vulnerable to such events. Regardless of the chosen technology, the IoT monitoring network will be more robust, since it uses small antennas and lower towers, and often a given area is covered by multiple base stations. The tool can be used to deploy new services in the nonserved area (e.g., 4G in the 700 MHz band at a lower cost or using TVWS techniques to provide communications and internet connection) and optimal interference management.

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Bento, Ricardo Ferreira, Aroldo Miniti, Tanit Ganz Sanchez, Adolfo Leiner et Carlos Augusto Nunes. « A Pathway for Information Transmission to the Ear ». Ear, Nose & ; Throat Journal 74, n^o 9 (septembre 1995) : 640–44. http://dx.doi.org/10.1177/014556139507400910.

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The use of implantable hearing aids and cochlear implants as an aid to neurosensory deafness is becoming an established procedure. The transmission of a processed speech signal is accomplished either transcutaneously via radiofrequency or percutaneously by connector coupling. Whereas the former is sensitive to electromagnetic interference, the latter increases the risk of infection. To overcome these disadvantages, an infrared (IR) system for transmission through the tympanic membrane was devised and tested. The transmitter/receiver consisted of an IR light emitting diode (LED;920nm) and a photovoltaic cell. The LED was placed inside the auditory canal of four dogs and the photovoltaic cell in the tympanic cavity over the cochlear promontory. A sinusoidal signal modulation was applied to the LED. The emitted signal was detected undistorted after crossing the tympanic membrane, with an average absorbance of 20%. High-frequency cut-off was adequate for cochlear implant purposes and audio prosthetic devices in general. The authors conclude that the tympanic membrane may be used as a translucent sealed interface to transmit data in the audio range to the middle and inner ears, with small power loss, good frequency response, and immunity to interface.

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Wang, Guo et Wang. « Exploring the Laplace Prior in Radio Tomographic Imaging with Sparse Bayesian Learning towards the Robustness to Multipath Fading ». Sensors 19, n^o 23 (22 novembre 2019) : 5126. http://dx.doi.org/10.3390/s19235126.

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Radio tomographic imaging (RTI) is a technology for target localization by using radiofrequency (RF) sensors in a wireless network. The change of the attenuation field caused by thetarget is represented by a shadowing image, which is then used to estimate the target’s position.The shadowing image can be reconstructed from the variation of the received signal strength (RSS)in the wireless network. However, due to the interference from multi-path fading, not all the RSSvariations are reliable. If the unreliable RSS variations are used for image reconstruction, someartifacts will appear in the shadowing image, which may cause the target’s position being wronglyestimated. Due to the sparse property of the shadowing image, sparse Bayesian learning (SBL) canbe employed for signal reconstruction. Aiming at enhancing the robustness to multipath fading,this paper explores the Laplace prior to characterize the shadowing image under the frameworkof SBL. Bayesian modeling, Bayesian inference and the fast algorithm are presented to achieve themaximum-a-posterior (MAP) solution. Finally, imaging, localization and tracking experiments fromthree different scenarios are conducted to validate the robustness to multipath fading. Meanwhile,the improved computational efficiency of using Laplace prior is validated in the localization-timeexperiment as well.

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Kaziz, Sinda, Mohamed Hadj Said, Antonino Imburgia, Bilel Maamer, Denis Flandre, Pietro Romano et Fares Tounsi. « Radiometric Partial Discharge Detection : A Review ». Energies 16, n^o 4 (16 février 2023) : 1978. http://dx.doi.org/10.3390/en16041978.

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One of the most common failures or breakdowns that can occur in high-voltage (HV) equipment is due to partial discharges (PDs). This occurs as a result of inadequate insulation, aging, harsh environmental effects, or manufacturing flaws. PD detection and recognition methods have gained growing attention and have seen great progress in the past decades. Radiometric methods are one of the most investigated detection approaches due to their immunity to electromagnetic interference (EMI) and their capabilities to detect and locate PD activities in different applications such as transformers, cables, etc. Several review articles have been published to classify and categorize these works. Nonetheless, some concepts are missing, and some improvement techniques, such as PD detection at high-frequency (HF) and very high-frequency (VHF), have been overlooked. We present in this paper an exhaustive review study of state-of-the-art PD detection based on radiometric methods at different usable radiofrequency bands (i.e., HF, VHF, and UHF). Accordingly, we propose a new generic categorization approach based on the detected electromagnetic wave component (magnetic or electric fields) and pick-up location, either from free space or ground cable.

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Wang, Dong, Kai Zhang, ShaoLong Han et LingZhi Yu. « PainVision® Apparatus for Assessment of Efficacy of Pulsed Radiofrequency Combined with Pharmacological Therapy in the Treatment of Postherpetic Neuralgia and Correlations with Measurements ». BioMed Research International 2017 (2017) : 1–8. http://dx.doi.org/10.1155/2017/5670219.

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Objective. PainVision device was a developed application for the evaluation of pain intensity. The objective was to assess the efficacy and safety of pulsed radiofrequency (PRF) combined with pharmacological therapy in the treatment of postherpetic neuralgia (PHN). We also discussed the correlation of the measurements.Method. Forty patients with PHN were randomized for treatment with PRF combined with pharmacological therapy (PRF group,n=20) or pharmacological therapy (control group,n=20) at postoperative 48 hours. The efficacy measure was pain degree (PD) that was assessed by PainVision and visual analog scale (VAS), short form Mcgill pain questionnaire (SF-Mcgill), and numeric rate scale sleep interference score (NRSSIS). Correlations between PD, VAS, SF-Mcgill, and NRSSIS were determined.Results. The PD for persistent pain (PP) and breakthrough pain (BTP) at postoperative 48 hours assessed by PainVision were significantly lower in PRF group than in control group (PD-PP,P<0.01; PD-BTP,P<0.01). PD and VAS were highly correlated for both persistent pain (r=0.453,ρ=0.008) and breakthrough pain (r=0.64,ρ=0.001).Conclusion. PRF was well tolerated and superior to isolated pharmacological therapy in the treatment of PHN. PainVision device showed great value in the evaluation of pain intensity and PD had an excellent correlation with VAS and SF-Mcgill.

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Gouvinhas, Cláudia, Dalila Veiga, Liliane Mendonça, Rute Sampaio, Luís Filipe Azevedo et José Manuel Castro-Lopes. « Interventional Pain Management in Multidisciplinary Chronic Pain Clinics : A Prospective Multicenter Cohort Study with One-Year Follow-Up ». Pain Research and Treatment 2017 (15 octobre 2017) : 1–11. http://dx.doi.org/10.1155/2017/8402413.

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Background. Interventional Pain Management (IPM) is performed in multidisciplinary chronic pain clinics (MCPC), including a range of invasive techniques to diagnose and treat chronic pain (CP) conditions. Current patterns of use of those techniques in MCPC have not yet been reported. Objective. We aimed to describe quantitatively and qualitatively the use of IPM and other therapeutic procedures performed on-site at four Portuguese MCPC. Methods. A prospective cohort study with one-year follow-up was performed in adult patients. A structured case report form was systematically completed at baseline and six and 12 months. Results. Among 808 patients referred to the MCPC, 17.2% had been prescribed IPM. Patients with IPM were on average younger and had longer CP duration and lower levels of maximum pain and pain interference/disability. The three main diagnoses were low back pain (n=28), postoperative CP, and knee pain (n=16 each). From 195 IPM prescribed, nerve blocks (n=108), radiofrequency (n=31), and viscosupplementation (n=22) were the most prevalent. Some IPM techniques were only available in few MCPC. One MCPC did not provide IPM. Conclusions. IPM are seldom prescribed in Portuguese MCPC. Further studies on IPM safety and effectiveness are necessary for clear understanding the role of these techniques in CP management.

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Mertens, F. G., M. Mevius, L. V. E. Koopmans, A. R. Offringa, G. Mellema, S. Zaroubi, M. A. Brentjens et al. « Improved upper limits on the 21 cm signal power spectrum of neutral hydrogen at z ≈ 9.1 from LOFAR ». Monthly Notices of the Royal Astronomical Society 493, n^o 2 (5 février 2020) : 1662–85. http://dx.doi.org/10.1093/mnras/staa327.

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ABSTRACT A new upper limit on the 21 cm signal power spectrum at a redshift of z ≈ 9.1 is presented, based on 141 h of data obtained with the Low-Frequency Array (LOFAR). The analysis includes significant improvements in spectrally smooth gain-calibration, Gaussian Process Regression (GPR) foreground mitigation and optimally weighted power spectrum inference. Previously seen ‘excess power’ due to spectral structure in the gain solutions has markedly reduced but some excess power still remains with a spectral correlation distinct from thermal noise. This excess has a spectral coherence scale of 0.25–0.45 MHz and is partially correlated between nights, especially in the foreground wedge region. The correlation is stronger between nights covering similar local sidereal times. A best 2-σ upper limit of $\Delta ^2_{21} \lt (73)^2\, \mathrm{mK^2}$ at $k = 0.075\, \mathrm{h\, cMpc^{-1}}$ is found, an improvement by a factor ≈8 in power compared to the previously reported upper limit. The remaining excess power could be due to residual foreground emission from sources or diffuse emission far away from the phase centre, polarization leakage, chromatic calibration errors, ionosphere, or low-level radiofrequency interference. We discuss future improvements to the signal processing chain that can further reduce or even eliminate these causes of excess power.

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