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Journal articles on the topic 'Ranging signal acquisition time'
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Ji, Xiao Dong, Zi Xian Yang, Xu Li, Guang Hui Xue, and Miao Wu. "Study on Method for Real-Time Vibration Signal of Shearer Acquisition." Applied Mechanics and Materials 373-375 (August 2013): 865–69. http://dx.doi.org/10.4028/www.scientific.net/amm.373-375.865.
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In order to acquire and analyze the real-time vibration signals of shearer in the process of coal mining. This experiment used the portable vibration measurement data recorder, which developed by ourselves. We design a comprehensive set of solutions for data acquisition according to underground mining machines working in real time. Through the data collection package, obtained a shearer vibration signal sample on real-time working. Meanwhile, analyze the vibration signal using signal analysis method. Through the experiment we acquire vibration signals of shearer's ranging-arms on real-time working, and the analysis results indicate that data collection solution is reasonably practicable.
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Diouf, Cherif, Gerard J. M. Janssen, Han Dun, Tarik Kazaz, and Christian C. J. M. Tiberius. "A USRP-Based Testbed for Wideband Ranging and Positioning Signal Acquisition." IEEE Transactions on Instrumentation and Measurement 70 (2021): 1–15. http://dx.doi.org/10.1109/tim.2021.3065449.
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Wu, Xing Cun, Ping Gong, Hai Jun Song, and Hui Zhi Zou. "An FFT-Based Approach for Carrier Frequency Domain Acquisition in Spread Spectrum TT&C System." Applied Mechanics and Materials 135-136 (October 2011): 211–16. http://dx.doi.org/10.4028/www.scientific.net/amm.135-136.211.
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Acquisition time of precision ranging code is long under the conditions of large Doppler shift, the carrier frequency domain FFT-based fast acquisition theory was analyzed, and the method of carrier Doppler compensation estimates to complete the PN code Doppler compensation was directly used in spread spectrum ranging signal acquisition. Comparing with the traditional parallel acquisition approach, the Doppler frequency estimation accuracy and acquisition speed is greatly improved, the acquisition time is shorter than long code segment with the traditional parallel acquisition method. Comparing with the method of short code supporting for long code, the channel energy is saved.
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Li, Zhikang, Bo Liu, Huachuang Wang, Zhen Chen, Qun Zhang, Kangjian Hua, and Jing Yang. "Target Tracking and Ranging Based on Single Photon Detection." Photonics 8, no. 7 (July 15, 2021): 278. http://dx.doi.org/10.3390/photonics8070278.
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In order to achieve non-cooperative target tracking and ranging in conditions of a weak echo signal, this paper presents a real-time acquisition, pointing, tracking (APT), and ranging (APTR) lidar system based on single photon detection. With this system, an active target APT mechanism based on a single photon detector is proposed. The target tracking and ranging strategy and the simulation of target APT are presented. Experiments in the laboratory show that the system has good performance to achieve the acquisition, pointing and ranging of a static target, and track a dynamic target (angular velocity around 3 mrad/s) under the condition of extremely weak echo signals (a dozen photons). Meanwhile, through further theoretical analysis, it can be proven that the mechanism has stronger tracking and detection ability in long distance. It can achieve the active tracking of the target with a lateral velocity of hundreds of meters per second at about one hundred kilometers distance. This means that it has the ability of fast long-distance non-cooperative target tracking and ranging, only by using a single-point single photon detector.
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Incoronato, Alfonso, Mauro Locatelli, and Franco Zappa. "Statistical Modelling of SPADs for Time-of-Flight LiDAR." Sensors 21, no. 13 (June 30, 2021): 4481. http://dx.doi.org/10.3390/s21134481.
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Time-of-Flight (TOF) based Light Detection and Ranging (LiDAR) is a widespread technique for distance measurements in both single-spot depth ranging and 3D mapping. Single Photon Avalanche Diode (SPAD) detectors provide single-photon sensitivity and allow in-pixel integration of a Time-to-Digital Converter (TDC) to measure the TOF of single-photons. From the repetitive acquisition of photons returning from multiple laser shots, it is possible to accumulate a TOF histogram, so as to identify the laser pulse return from unwelcome ambient light and compute the desired distance information. In order to properly predict the TOF histogram distribution and design each component of the LiDAR system, from SPAD to TDC and histogram processing, we present a detailed statistical modelling of the acquisition chain and we show the perfect matching with Monte Carlo simulations in very different operating conditions and very high background levels. We take into consideration SPAD non-idealities such as hold-off time, afterpulsing, and crosstalk, and we show the heavy pile-up distortion in case of high background. Moreover, we also model non-idealities of timing electronics chain, namely, TDC dead-time, limited number of storage cells for TOF data, and TDC sharing. Eventually, we show how the exploit the modelling to reversely extract the original LiDAR return signal from the distorted measured TOF data in different operating conditions.
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Roule, Petr, Ondřej Jakubov, Pavel Kovář, Petr Kařmařík, and František Vejražka. "Gnss Signal Processing in Gpu." Artificial Satellites 48, no. 2 (June 1, 2013): 51–61. http://dx.doi.org/10.2478/arsa-2013-0005.
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ABSTRACT Signal processing of the global navigation satellite systems (GNSS) is a computationally demanding task due to the wide bandwidth of the signals and their complicated modulation schemes. The classical GNSS receivers therefore utilize tailored digital signal processors (DSP) not being flexible in nature. Fortunately, the up-to-date parallel processors or graphical processing units (GPUs) dispose sufficient computational power for processing of not only relatively narrow band GPS L1 C/A signal but also the modernized GPS, GLONASS, Galileo and COMPASS signals. The performance improvement of the modern processors is based on the constantly increasing number of cores. This trend is evident not only from the development of the central processing units (CPUs), but also from the development of GPUs that are nowadays equipped with up to several hundreds of cores optimized for video signals. GPUs include special vector instructions that support implementation of massive parallelism. The new GPUs, named as general-purpose computation on graphics processing units (GPGPU), are able to process both graphic and general data, thus making the GNSS signal processing possible. Application programming interfaces (APIs) supporting GPU parallel processing have been developed and standardized. The most general one, Open Computing Language (Open CL), is now supported by most of the GPU vendors. Next, Compute Unified Device Architecture (CUDA) language was developed for NVidia graphic cards. The CUDA language features optimized signal processing libraries including efficient implementation of the fast Fourier transform (FFT). In this paper, we study the applicability of the GPU approach in GNSS signal acquisition. Two common parallel DSP methods, parallel code space search (PCSS) and double-block zero padding (DBZP), have been investigated. Implementations in the C language for CPU and the CUDA language for GPU are discussed and compared with respect to the acquisition time. It is shown that for signals with long ranging codes (with 10230 number of chips - Galileo E5, GPS L5 etc.). Paper presented at the "European Navigation Conference 2012", held in Gdansk, Poland
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Satyanarayana, A. N., B. Chandrashekara Rao, D. Lalitha, and B. Lakshmi. "Modis data acquisition and utilization for forest fire management in india." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-8 (December 23, 2014): 1383–87. http://dx.doi.org/10.5194/isprsarchives-xl-8-1383-2014.
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The Moderate Resolution Imaging Spectroradiometer (MODIS) instrument onboard Terra & Aqua Spacecrafts Scans the earth in 36 spectral bands & covers the entire earth in two days. MODIS data has proved to be very useful for ocean & land studies with resolution ranging from 250 m to 1000 meters. The Data Reception system at Shadnagar (Refer to the Block diagram Fig.1), receives the data transmitted in X-band on 8160 MHz carrier SQPSK modulated with a data rate of 15 MBPS from the Aqua satellite. The down converted IF signal is fed to the demodulator & bit-synchronizer unit. The data and clock output signals of bitsynchronizer unit are given to a PC based DAQLB system where real-time telemetry processing is carried out and data is recorded onto hard disk in real time. The effectiveness of the system in supporting the forest fire management during the 2011, 12, 13 & 14 is also presented in the paper. Near real-time active fire monitoring, interactive fire visualization, fire database and statistical analysis functions also presented. Preliminary results of the upgrading satellite receiving system and in expanding the utilization of satellite data for multi-disciplinary resources management will also be presented and discussed.
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Coccia, Armando, Federica Amitrano, Leandro Donisi, Giuseppe Cesarelli, Gaetano Pagano, Mario Cesarelli, and Giovanni D'Addio. "Design and validation of an e-textile-based wearable system for remote health monitoring." ACTA IMEKO 10, no. 2 (June 29, 2021): 220. http://dx.doi.org/10.21014/acta_imeko.v10i2.912.
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<p class="Abstract">The paper presents a new e-textile-based system, named SWEET Shirt, for the remote monitoring of biomedical signals. The system includes a textile sensing shirt, an electronic unit for data transmission, a custom-made Android application for real-time signal visualisation and a software desktop for advanced digital signal processing. The device allows for the acquisition of electrocardiographic, bicep electromyographic and trunk acceleration signals. The sensors, electrodes, and bus structures are all integrated within the textile garment, without any discomfort for users. A wide-ranging set of algorithms for signal processing were also developed for use within the system, allowing clinicians to rapidly obtain a complete and schematic overview of a patient’s clinical status. The aim of this work was to present the design and development of the device and to provide a validation analysis of the electrocardiographic measurement and digital processing. The results demonstrate that the information contained in the signals recorded by the novel system is comparable to that obtained via a standard medical device commonly used in clinical environments. Similarly encouraging results were obtained in the comparison of the variables derived from the signal processing.</p>
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Du, Wen Ya, Wei Ping Song, Deng Chao Feng, and Li Hong Zhang. "Study on GPS Ranging Technology for Intelligent Detection of Subgrade Compaction." Applied Mechanics and Materials 220-223 (November 2012): 1533–38. http://dx.doi.org/10.4028/www.scientific.net/amm.220-223.1533.
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Subgrade compaction is an important task in modern traffic fields, where GPS ranging technology is one of the key technologies in intelligent compaction. In the paper, NMEA communication protocol was illustrated, the statement of GPGGA was analyzed, and the extraction of the single point geographical coordinate was realized correspondingly. Aimed at the phenomenon of data loss in signal drift and data acquisition, the missing data estimation algorithm for longitude and latitude was adopted to obtain the complete data sets as well. Finally, the deficiencies of the traditional longitude and latitude distance measuring formula were analyzed and a new model of measuring distance of longitude and latitude was discussed. The experimental results show that the method has the better stability of measurement, the higher test accuracy, which has a good application prospects in intelligent compaction. However, the real-time property of data processing still needs further research.
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Jiang, Zhonghui, Wu Huang, Xiao Wei, Defu Cheng, and Dan Li. "Self-Adaptive Dynamic Ranging Model-Based Real-Time Hybrid Algorithm for Accurate Indoor Localization." International Journal of Computer and Communication Engineering 9, no. 4 (2020): 167–84. http://dx.doi.org/10.17706/ijcce.2020.9.4.167-184.
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The reliability of location information still maintains a crucial impact on restricting the development of location based services in indoor environment. However, in wireless local area network, received signal strength indicator (RSSI) is prone to be interfered by indoor complex environment, resulting in low accuracy and instability of real-time positioning. Here, the new self-adaptive dynamic ranging model-based real-time hybrid algorithm was proposed to realize accurate and undisturbed localization in indoor scenes. A self-adaptive dynamic ranging model was initially constructed to update the environmental parameters and correct the ranging values of mobile terminals in real time. Based on this model, a hybrid KNN algorithm and a hybrid Bayesian algorithm were severally presented. Location fingerprint database and real-time RSSI data of test points were then obtained through data acquisition. Finally, the acquired data was further used to verify the two hybrid algorithms proposed, and compared with the results of several conventional algorithms. As a result, the stability and accuracy of dual hybrid algorithms were better than those of the traditional ones. The range of average location error of both hybrid algorithms maintained 1.26-1.38 m, which was significantly lower than the error level of 2-5 m under the current WLAN environment. This newly proposed hybrid algorithm could effectively improve the stability and accuracy of indoor localization with real-time positioning algorithm, providing a promising solution for RSSI-based indoor positioning system.
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Altaf, Eyneen, and Ajay Kumar. "Design and Development of Compact Hand Held Target Acquisition Device." Defence Science Journal 67, no. 2 (March 14, 2017): 154. http://dx.doi.org/10.14429/dsj.67.11179.
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A compact, lightweight hand held target acquisition device, comprising of an infra red imager, colour CCD camera, eye safe laser range finder, global positioning system and digital magnetic compass has been developed. The aim was to develop a compact, lightweight, modular and man-portable multi function electro-optical system with a recognition range of 1 km for vehicles and 500 m for human movement enabling day and night time surveillance, target ranging capability, ability to generate coordinates of the operator and estimation of target coordinates. Hand Held target acquisition device operates on 12 V DC, has integrated signal processing for all the sensors and display electronics with a weight of 3 kg. Overview of the system, design methodology, performance modeling, range simulation of both the IR imager and colour CCD camera and field results have been presented.
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Coulson, Larry D., Davinder S. Nagra, Xijian Guo, Randy M. Whittal, and Liang Li. "Mass Spectral Recording and Storing System Based on GPIB Data Transfer for Laser Ionization Time-of-Flight Mass Spectrometry." Applied Spectroscopy 48, no. 9 (September 1994): 1125–31. http://dx.doi.org/10.1366/0003702944029424.
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A data acquisition scheme based on a general-purpose interface bus (GPIB) for data transfer from a digital storage oscilloscope (DSO) to a PC is investigated for recording and storing transient signals generated by laser-induced multiphoton ionization or laser desorption ionization time-of-flight mass spectrometry. With this scheme and the use of commercial software, the data acquisition rate is generally low, typically 1 or 2 Hz for 20-Kbyte transients. We have developed a software to maximize the speed of data transfer and storage. This software is incorporated into LabWindows for data analysis. We demonstrate that it is possible to record and store mass spectra at a speed ranging from 14 spectra/s for a transient record length of 20 Kbytes to 50 spectra/s for a record length of 1 Kbyte by using this DSO-GPIB-PC scheme. This simple and readily adaptable system is found to be adequate and useful for many operations in laser work where relatively higher repetition rates are required. The applications of the system are demonstrated for recording and constructing ion chromatograms in liquid chromatography/time-of-flight mass spectrometry. In addition, it is shown that the data system can not only replace the traditional boxcar integrator for signal monitoring but also provide multiple ion monitoring for recording wavelength spectra in laser ionization spectroscopy.
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Pace, Charles F., Steven M. Thornberg, and Jon R. Maple. "Luminescence Instrument for the Acquisition of Low-Temperature Fluorescence and Phosphorescence Spectra." Applied Spectroscopy 42, no. 5 (July 1988): 891–96. http://dx.doi.org/10.1366/0003702884428941.
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An inexpensive, simple (but highly automated) instrument for acquiring high-resolution fluorescence and phosphorescence spectra of polycyclic aromatic hydrocarbons (PAHs) is described. Fluorescence and phosphorescence signals are processed by gated integration and photon counting, respectively. The instrument can be used to acquire excitation as well as emission spectra in both the frequency and time domain. In addition, a method for measuring single and double exponential phosphorescence decay times is presented. Decay times ranging from 0.3 ms to 300 ms were measured for several naphthalene derivatives, with a precision of ∼10%. The primary advantages of this instrument are high sensitivity, high selectivity, wide linear dynamic ranges, and a versatile range of applications.
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Kim, Seong Min, and Michael J. McCarthy. "Analysis of Characteristics of In-Line Magnetic Resonance Sensor." Key Engineering Materials 321-323 (October 2006): 1221–24. http://dx.doi.org/10.4028/www.scientific.net/kem.321-323.1221.
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This study was performed to show the feasibility of nuclear magnetic resonance (NMR) techniques for quality evaluation of various agricultural and food products. A real-time in-line NMR quality evaluation sensor was designed, constructed and tested. The device consists of an NMR spectrometer coupled to a conveyor system and a data acquisition system. The conveyor was run at speeds ranging from 0 to 300 mm/s. An NMR signal can be detected when a sample is within ±50 mm of the NMR coil center. The response of NMR sensor was tested using several fruits. The results showed a feasibility of an NMR sensor for evaluating internal quality of various fruits.
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Zhou, Ping, Liu Yang, and Yao-Xiong Huang. "A Smart Phone Based Handheld Wireless Spirometer with Functions and Precision Comparable to Laboratory Spirometers." Sensors 19, no. 11 (May 31, 2019): 2487. http://dx.doi.org/10.3390/s19112487.
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We report a smart phone based handheld wireless spirometer which uses a Lilly type sensing flowhead for respiratory signal acquisition and transmits the data to smartphone or other mobile terminals with Bluetooth signal transmission for data processing and result display. The developed spirometer was demonstrated to be able to detect flow rates ranging from 0–15 L/s with an accuracy of 4 mL/s, and can perform tests of flow volume (FV), forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), peak expiratory flow (PEF), etc. By having the functions and precision comparable to laboratory spirometers, it satisfies the American Thoracic Society and European Respiratory Society (ATS/ERS) proposed performance requirements for spirometer. At the same time, it is low cost, light and handy, low power consumption battery-powered. The test of 12 cases of subjects using the developed spirometer also indicated that it was easy to use for both providers and patients, and suitable for the Point of Care Test (POCT) of chronic obstructive pulmonary disease (COPD) and asthma at general-practice settings and homes.
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Yuan, Gao, Zhao Ze, Huang Changcheng, Han Chuanqi, and Cui Li. "In-vehicle localization based on multi-channel Bluetooth Low Energy received signal strength indicator." International Journal of Distributed Sensor Networks 16, no. 1 (January 2020): 155014771990009. http://dx.doi.org/10.1177/1550147719900093.
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High-precision in-vehicle localization is the basis for both in-vehicle location-based service and the analysis of the driver or passengers’ behaviors. However, interferences like effects of multipath and reflection of the signals significantly raise great challenges to the positioning accuracy at in-vehicle environment. This article presents a novel high-precision in-vehicle localization method, namely, the LOC-in-a-Car, based on functional exploration and full use of multi-channel received signal strength indicator of Bluetooth Low Energy. To achieve higher positioning precision, a hierarchical computation algorithm based on Adaboost and support vector machine is proposed in our method. In particular, we also proposed a device calibration method to deal with the heterogeneity of different smartphone terminals. We developed an Android app as a component in which the channel time-sharing acquisition method is fulfilled, enabling smartphones to distinguish data from multi-channels. The system performance is verified via intensive experiments, of which the results show that our method can distinguish the locations of driver or passengers with an accuracy ranging from 86.80% to 92.02% for each seat on Nexus phone, and the overall accuracy is 89.86%, with standard deviation of 2.64%. On Huawei phone, the accuracy ranges from 85.43% to 93.33% with overall accuracy of 89.75% and standard deviation of 3.07%. Both outperform the existing methods.
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Martucci, Giovanni, Francisco Navas-Guzmán, Ludovic Renaud, Gonzague Romanens, S. Mahagammulla Gamage, Maxime Hervo, Pierre Jeannet, and Alexander Haefele. "Validation of pure rotational Raman temperature data from the Raman Lidar for Meteorological Observations (RALMO) at Payerne." Atmospheric Measurement Techniques 14, no. 2 (February 22, 2021): 1333–53. http://dx.doi.org/10.5194/amt-14-1333-2021.
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Abstract. The Raman Lidar for Meteorological Observations (RALMO) is operated at the MeteoSwiss station of Payerne (Switzerland) and provides, amongst other products, continuous measurements of temperature since 2010. The temperature profiles are retrieved from the pure rotational Raman (PRR) signals detected around the 355 nm Cabannes line. The transmitter and receiver systems of RALMO are described in detail, and the reception and acquisition units of the PRR channels are thoroughly characterized. The FastCom P7888 card used to acquire the PRR signal, the calculation of the dead time and the desaturation procedure are also presented. The temperature profiles retrieved from RALMO PRR data during the period going from July 2017 to the end of December 2018 have been validated against two reference operational radiosounding systems (ORSs) co-located with RALMO, i.e. the Meteolabor SRS-C50 and the Vaisala RS41. The ORSs have also served to perform the calibration of the RALMO temperature during the validation period. The maximum bias (ΔTmax), mean bias (μ) and mean standard deviation (σ) of RALMO temperature Tral with respect to the reference ORS, Tors, are used to characterize the accuracy and precision of Tral along the troposphere. The daytime statistics provide information essentially about the lower troposphere due to lower signal-to-noise ratio. The ΔTmax, μ and σ of the differences ΔT=Tral-Tors are, respectively, 0.28, 0.02±0.1 and 0.62±0.03 K. The nighttime statistics provide information for the entire troposphere and yield ΔTmax=0.29 K, μ=0.05±0.34 K and σ=0.66±0.06 K. The small ΔTmax, μ and σ values obtained for both daytime and nighttime comparisons indicate the high stability of RALMO that has been calibrated only seven times over 18 months. The retrieval method can correct for the largest sources of correlated and uncorrelated errors, e.g. signal noise, dead time of the acquisition system and solar background. Especially the solar radiation (scattered into the field of view from the zenith angle Φ) affects the quality of PRR signals and represents a source of systematic error for the retrieved temperature. An imperfect subtraction of the background from the daytime PRR profiles induces a bias of up to 2 K at all heights. An empirical correction f(Φ) ranging from 0.99 to 1 has therefore been applied to the mean background of the PRR signals to remove the bias. The correction function f(Φ) has been validated against the numerical weather prediction model COSMO (Consortium for Small-scale Modelling), suggesting that f(Φ) does not introduce any additional source of systematic or random error to Tral. A seasonality study has been performed to help with understanding if the overall daytime and nighttime zero bias hides seasonal non-zero biases that cancel out when combined in the full dataset.
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Zhu, Fu-guang, Dong-sheng Xu, Rui-shan Tan, Bin Peng, He Huang, and Zhuo-wen Liu. "Development of Optic-Electric Hybrid Sensors for the Real-Time Intelligent Monitoring of Subway Tunnels." Journal of Sensors 2021 (July 12, 2021): 1–10. http://dx.doi.org/10.1155/2021/8871893.
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The settlement and deformation monitoring of subway tunnels had difficult in long-distance and real time measurement. This study proposed an optic-electric hybrid sensor based on infrared laser ranging technology and cable-sensing technology. The working principle, hardware layer, design details, laboratory calibration and field validation were presented and discussed. The optic-electric hybrid sensor implemented the real-time intelligent analysis modulus for the whole system which could analysis the measurement errors and improve the accuracy. The laboratory calibration tests were carried out and the results shown that the hybrid sensors had measurement resolution of 1 mm with the maximum measurement range of 100 m. A remote real-time intelligent monitoring system is established based on the hybrid sensors. The system contains an edge computing module, real-time communication module and warning light signal with three colors. The stability of data acquisition and transmission of the intelligent control monitoring system under long-term conditions was examined. Test results shown that the system was quite stable for the long-term measurement. The whole system was verified in a constructing subway tunnel of Wuhan Metro Line 8, China. According to the field monitoring results, the deformations and the state of health safety of the tunnel was evaluated. The results of this study could provide useful guidance for tunnel deformation monitoring and has great practical value in civil engineering.
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Oletic, Dinko, and Vedran Bilas. "System-Level Power Consumption Analysis of the Wearable Asthmatic Wheeze Quantification." Journal of Sensors 2018 (2018): 1–18. http://dx.doi.org/10.1155/2018/6564158.
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Long-term quantification of asthmatic wheezing envisions an m-Health sensor system consisting of a smartphone and a body-worn wireless acoustic sensor. As both devices are power constrained, the main criterion guiding the system design comes down to minimization of power consumption, while retaining sufficient respiratory sound classification accuracy (i.e., wheeze detection). Crucial for assessment of the system-level power consumption is the understanding of trade-off between power cost of computationally intensive local processing and communication. Therefore, we analyze power requirements of signal acquisition, processing, and communication in three typical operating scenarios: (1) streaming of uncompressed respiratory signal to a smartphone for classification, (2) signal streaming utilizing compressive sensing (CS) for reduction of data rate, and (3) respiratory sound classification onboard the wearable sensor. Study shows that the third scenario featuring the lowest communication cost enables the lowest total sensor system power consumption ranging from 328 to 428 μW. In such scenario, 32-bit ARM Cortex M3/M4 cores typically embedded within Bluetooth 4 SoC modules feature the optimal trade-off between onboard classification performance and consumption. On the other hand, study confirms that CS enables the most power-efficient design of the wearable sensor (216 to 357 μW) in the compressed signal streaming, the second scenario. In such case, a single low-power ARM Cortex-A53 core is sufficient for simultaneous real-time CS reconstruction and classification on the smartphone, while keeping the total system power within budget for uncompressed streaming.
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Abbattista, Cristoforo, Leonardo Amoruso, Samuel Burri, Edoardo Charbon, Francesco Di Lena, Augusto Garuccio, Davide Giannella, et al. "Towards Quantum 3D Imaging Devices." Applied Sciences 11, no. 14 (July 12, 2021): 6414. http://dx.doi.org/10.3390/app11146414.
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We review the advancement of the research toward the design and implementation of quantum plenoptic cameras, radically novel 3D imaging devices that exploit both momentum–position entanglement and photon–number correlations to provide the typical refocusing and ultra-fast, scanning-free, 3D imaging capability of plenoptic devices, along with dramatically enhanced performances, unattainable in standard plenoptic cameras: diffraction-limited resolution, large depth of focus, and ultra-low noise. To further increase the volumetric resolution beyond the Rayleigh diffraction limit, and achieve the quantum limit, we are also developing dedicated protocols based on quantum Fisher information. However, for the quantum advantages of the proposed devices to be effective and appealing to end-users, two main challenges need to be tackled. First, due to the large number of frames required for correlation measurements to provide an acceptable signal-to-noise ratio, quantum plenoptic imaging (QPI) would require, if implemented with commercially available high-resolution cameras, acquisition times ranging from tens of seconds to a few minutes. Second, the elaboration of this large amount of data, in order to retrieve 3D images or refocusing 2D images, requires high-performance and time-consuming computation. To address these challenges, we are developing high-resolution single-photon avalanche photodiode (SPAD) arrays and high-performance low-level programming of ultra-fast electronics, combined with compressive sensing and quantum tomography algorithms, with the aim to reduce both the acquisition and the elaboration time by two orders of magnitude. Routes toward exploitation of the QPI devices will also be discussed.
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Mittelmeier, Niko, Julian Allin, Tomas Blodau, Davide Trabucchi, Gerald Steinfeld, Andreas Rott, and Martin Kühn. "An analysis of offshore wind farm SCADA measurements to identify key parameters influencing the magnitude of wake effects." Wind Energy Science 2, no. 2 (October 18, 2017): 477–90. http://dx.doi.org/10.5194/wes-2-477-2017.
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Abstract. For offshore wind farms, wake effects are among the largest sources of losses in energy production. At the same time, wake modelling is still associated with very high uncertainties. Therefore current research focusses on improving wake model predictions. It is known that atmospheric conditions, especially atmospheric stability, crucially influence the magnitude of those wake effects. The classification of atmospheric stability is usually based on measurements from met masts, buoys or lidar (light detection and ranging). In offshore conditions these measurements are expensive and scarce. However, every wind farm permanently produces SCADA (supervisory control and data acquisition) measurements. The objective of this study is to establish a classification for the magnitude of wake effects based on SCADA data. This delivers a basis to fit engineering wake models better to the ambient conditions in an offshore wind farm. The method is established with data from two offshore wind farms which each have a met mast nearby. A correlation is established between the stability classification from the met mast and signals within the SCADA data from the wind farm. The significance of these new signals on power production is demonstrated with data from two wind farms with met mast and long-range lidar measurements. Additionally, the method is validated with data from another wind farm without a met mast. The proposed signal consists of a good correlation between the standard deviation of active power divided by the average power of wind turbines in free flow with the ambient turbulence intensity (TI) when the wind turbines were operating in partial load. It allows us to distinguish between conditions with different magnitudes of wake effects. The proposed signal is very sensitive to increased turbulence induced by neighbouring turbines and wind farms, even at a distance of more than 38 rotor diameters.
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Bellon, Véronique, Jean Louis Vigneau, and Michel Leclercq. "Feasibility and Performances of a New, Multiplexed, Fast and Low-Cost Fiber-Optic NIR Spectrometer for the On-Line Measurement of Sugar in Fruits." Applied Spectroscopy 47, no. 7 (July 1993): 1079–83. http://dx.doi.org/10.1366/0003702934415255.
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This paper describes an attempt to develop a new NIR spectrometer to sort fruits according to the sugar content in the conditioning stations. This spectrometer, ranging from 800 to 1050 nm, is based on diode array technology. It is coupled with fiber optics, which allow multiplexing; 20 fibers have been detected by the camera, showing the potential multiplexing of 20 different points. The acquisition time is 40 ms per image (i.e., 2 ms per spectrum). A good signal-to-noise ratio has been recorded in the 820–1010 nm range. This spectrometer has been tested with a set of 79 peaches. Partial least-squares processing is applied to different wavelength ranges. The best coefficient of correlation, achieved with a reduced wavelength range (from 847 to 977 nm), is 0.81, and the standard error of prediction is 1.04°Brix. With this calibration, the fruits can be sorted into three maturity classes with a reliability of 76%. This performance, as well as the other characteristics of the instrument, is in accordance with the requirements of the conditioning station managers.
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Pavillon, Nicolas, Katsumasa Fujita, and Nicholas Isaac Smith. "Multimodal label-free microscopy." Journal of Innovative Optical Health Sciences 07, no. 05 (September 2014): 1330009. http://dx.doi.org/10.1142/s1793545813300097.
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This paper reviews the different multimodal applications based on a large extent of label-free imaging modalities, ranging from linear to nonlinear optics, while also including spectroscopic measurements. We put specific emphasis on multimodal measurements going across the usual boundaries between imaging modalities, whereas most multimodal platforms combine techniques based on similar light interactions or similar hardware implementations. In this review, we limit the scope to focus on applications for biology such as live cells or tissues, since by their nature of being alive or fragile, we are often not free to take liberties with the image acquisition times and are forced to gather the maximum amount of information possible at one time. For such samples, imaging by a given label-free method usually presents a challenge in obtaining sufficient optical signal or is limited in terms of the types of observable targets. Multimodal imaging is then particularly attractive for these samples in order to maximize the amount of measured information. While multimodal imaging is always useful in the sense of acquiring additional information from additional modes, at times it is possible to attain information that could not be discovered using any single mode alone, which is the essence of the progress that is possible using a multimodal approach.
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Mora, Carla, Juan Javier Jiménez, Pedro Pina, João Catalão, and Gonçalo Vieira. "Evaluation of single-band snow-patch mapping using high-resolution microwave remote sensing: an application in the maritime Antarctic." Cryosphere 11, no. 1 (January 23, 2017): 139–55. http://dx.doi.org/10.5194/tc-11-139-2017.
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Abstract. The mountainous and ice-free terrains of the maritime Antarctic generate complex mosaics of snow patches, ranging from tens to hundreds of metres. These can only be accurately mapped using high-resolution remote sensing. In this paper we evaluate the application of radar scenes from TerraSAR-X in High Resolution SpotLight mode for mapping snow patches at a test area on Fildes Peninsula (King George Island, South Shetlands). Snow-patch mapping and characterization of snow stratigraphy were conducted at the time of image acquisition on 12 and 13 January 2012. Snow was wet in all studied snow patches, with coarse-grain and rounded crystals showing advanced melting and with frequent ice layers in the snow pack. Two TerraSAR-X scenes in HH and VV polarization modes were analysed, with the former showing the best results when discriminating between wet snow, lake water and bare soil. However, significant overlap in the backscattering signal was found. Average wet-snow backscattering was −18.0 dB in HH mode, with water showing −21.1 dB and bare soil showing −11.9 dB. Single-band pixel-based and object-oriented image classification methods were used to assess the classification potential of TerraSAR-X SpotLight imagery. The best results were obtained with an object-oriented approach using a watershed segmentation with a support vector machine (SVM) classifier, with an overall accuracy of 92 % and Kappa of 0.88. The main limitation was the west to north-west facing snow patches, which showed significant error, an issue related to artefacts from the geometry of satellite imagery acquisition. The results show that TerraSAR-X in SpotLight mode provides high-quality imagery for mapping wet snow and snowmelt in the maritime Antarctic. The classification procedure that we propose is a simple method and a first step to an implementation in operational mode if a good digital elevation model is available.
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Scafutto, Rebecca, and Carlos de Souza Filho. "Detection of Methane Plumes Using Airborne Midwave Infrared (3–5 µm) Hyperspectral Data." Remote Sensing 10, no. 8 (August 7, 2018): 1237. http://dx.doi.org/10.3390/rs10081237.
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Methane (CH4) display spectral features in several regions of the infrared range (0.75–14 µm), which can be used for the remote mapping of emission sources through the detection of CH4 plumes from natural seeps and leaks. Applications of hyperspectral remote sensing techniques for the detection of CH4 in the near and shortwave infrared (NIR-SWIR: 0.75–3 µm) and longwave infrared (LWIR: 7–14 µm) have been demonstrated in the literature with multiple sensors and scenarios. However, the acquisition and processing of hyperspectral data in the midwave infrared (MWIR: 3–5 µm) for this application is rather scarce. Here, a controlled field experiment was used to evaluate the potential for CH4 plume detection in the MWIR based on hyperspectral data acquired with the SEBASS airborne sensor. For comparison purposes, LWIR data were also acquired simultaneously with the same instrument. The experiment included surface and undersurface emission sources (ground stations), with flow rates ranging between 0.6–40 m3/h. The data collected in both ranges were sequentially processed using the same methodology. The CH4 plume was detected, variably, in both datasets. The gas plume was detected in all LWIR images acquired over nine gas leakage stations. In the MWIR range, the plume was detected in only four stations, wherein 18 m3/h was the lowest flux sensed. We demonstrate that the interference of target reflectance, the low contrast between plume and background and a low signal of the CH4 feature in the MWIR at ambient conditions possibly explain the inferior results observed for this range when compared to LWIR. Furthermore, we show that the acquisition time and weather conditions, including specific limits of temperature, humidity, and wind speed, proved critical for plume detection using daytime MWIR hyperspectral data.
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Vargas, David, Ivan Vasconcelos, Matteo Ravasi, and Nick Luiken. "Time-Domain Multidimensional Deconvolution: A Physically Reliable and Stable Preconditioned Implementation." Remote Sensing 13, no. 18 (September 15, 2021): 3683. http://dx.doi.org/10.3390/rs13183683.
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Multidimensional deconvolution constitutes an essential operation in a variety of geophysical scenarios at different scales ranging from reservoir to crustal, as it appears in applications such as surface multiple elimination, target-oriented redatuming, and interferometric body-wave retrieval just to name a few. Depending on the use case, active, microseismic, or teleseismic signals are used to reconstruct the broadband response that would have been recorded between two observation points as if one were a virtual source. Reconstructing such a response relies on the the solution of an ill-conditioned linear inverse problem sensitive to noise and artifacts due to incomplete acquisition, limited sources, and band-limited data. Typically, this inversion is performed in the Fourier domain where the inverse problem is solved per frequency via direct or iterative solvers. While this inversion is in theory meant to remove spurious events from cross-correlation gathers and to correct amplitudes, difficulties arise in the estimation of optimal regularization parameters, which are worsened by the fact they must be estimated at each frequency independently. Here we show the benefits of formulating the problem in the time domain and introduce a number of physical constraints that naturally drive the inversion towards a reduced set of stable, meaningful solutions. By exploiting reciprocity, time causality, and frequency-wavenumber locality a set of preconditioners are included at minimal additional cost as a way to alleviate the dependency on an optimal damping parameter to stabilize the inversion. With an interferometric redatuming example, we demonstrate how our time domain implementation successfully reconstructs the overburden-free reflection response beneath a complex salt body from noise-contaminated up- and down-going transmission responses at the target level.
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Xu, Weiwei, and Songyong Yuan. "A case study of seismograph self-noise test from Trillium 120QA seismometer and Reftek 130 data logger." Journal of Seismology 23, no. 6 (November 2019): 1347–55. http://dx.doi.org/10.1007/s10950-019-09872-9.
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Abstract Seismograph self-noise has become a de facto standard for instrument comparisons and their performance assessment and is considered as one of the most vital parameters for instrument comparison. For self-noise testing of modern force-balance feedback broadband seismometers, several factors have been thoroughly discussed and thought to be attributable to the self-noise estimate, including the data selection criteria, sensor alignment correction, timing error, correlation analysis method, and computational parameter selection during the computational process. This study focuses on some other factors, such as local site conditions, temperature insulating methods, and data logger self-noise interferences, with an aim to differentiate the self-noise contribution of these sources and their dependencies on time and frequency. A series of experiments were conducted at the Beijing National Earth Observatory using a Trillium 120QA seismometer and Reftek-130 data acquisition system at three different locations ranging from the ordinary equipment warehouse to global seismographic network level cave with a hard-rock base. Results show that noise-free site is necessary for the self-noise test in a frequency band greater than approximately 0.1 Hz. However, for a frequency band less than 0.1 Hz, the insulation method and installation procedures are far more important, although the influence of the site location cannot be neglected fully. A suitable preamp should be selected in the data logger configurations to ensure that the low-noise amplitude of the sensor signal is above the digitizer noise level.
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Zhang, Yanjun, and Minqiang Liu. "Application of Photoelectric Sensor in Control of Industrial Robot." Journal of Nanoelectronics and Optoelectronics 16, no. 2 (February 1, 2021): 324–32. http://dx.doi.org/10.1166/jno.2021.2960.
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Indoor positioning and automatic charging technology of the robot is an important indicator to test intelligent control of robot. The surrounding condition is collected by acousto-optic sensor and photoelectric sensor, and the closed-loop control of DC motor is realized based on Fuzzy PID. The system integrates multiple photoelectric sensors and uses high-performance processor, S3C6410 ARM11, as the core instead of PC, reducing the power consumption and cost, so as to complete the acquisition of ranging information. And the environment image is obtained for image processing. The infrared docking method is adopted in the docking process, that is, three infrared transmitting tubes in the charging dock emit different positions, and the position relative to the charging dock is judged according to the number of received signals. In the experiment, the positioning error of industrial robot is about 1%, which can meet the requirements of indoor positioning. The docking success rate of automatic charging is more than 98%, and the time spent is less than 65 seconds, which satisfies with the requirements of automatic charging.
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Bianchi, M. C., M. Tosetti, L. Biagi, A. Abbruzzese, A. M. Valleriani, D. Montanaro, R. Battini, and P. Carpeggiani. "Spettroscopia protonica, perfusione e diffusione RM dell'encefalo nella sclerosi tuberosa." Rivista di Neuroradiologia 16, no. 3 (June 2003): 553–61. http://dx.doi.org/10.1177/197140090301600345.
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Tuberous Sclerosis Complex (TSC) is a genetic disease affecting multiple systems. Brain is one of the most frequently involved organ and the standard intracranial hallmarks are cortical tuberous (CT), subependymal nodules (SEN) and giant cell astrocytoma (GCA). MRI findings are characteristic and are included among the diagnostic criteria set out by Roach. Functional MR acquisitions such as proton spectroscopy (1HMRS), perfusion (ASL-PI) and diffusion (DWI and DTI) are additional tools to conventional imaging which allow a deeper understanding of “in vivo” physiology and pathology of the brain. We have variably applied 1H MRS, ASL-PI and DWI- DTI in a series of patients with definite diagnosis of TSC. The aim was to assess the strength of these techniques in the clinical management of the most impaired patients, i.e. those with refractory epilepsy or with suspected GCA. Combined brain MR studies were performed in 15 patients with definite diagnosis of TSC using a 1.5 T MR system (Signa Horizon LX, GE Medical System, Milwaukee, Wis) with a maximum gradient capability of 23 mT/m and a slew rate of 120 T/m/s. 1H MRS was applied in 12 cortical tubers and one GCA. A short TE stimulated echo acquisition mode (STEAM) technique (TR = 2010 ms, TE = 30 ms, mixing time ? 13.7 ms, 128 scans, VOI dimension = 3.4 cc) was performed. Raw data were analysed off-line with the Spectral Analysis General Electric/Interactive Data Language (SAGE/IDL). The following metabolites were evaluated: N-acetyl-aspartate (NAA, at 2.01 ppm), Creatine/Phosphocreatine (Cr, at 3.05 ppm), Choline-containing compounds (Cho, at 3.25 ppm), Myo-Inositol (mI, at 3.56 ppm) and if detectable Lactate (Lac, at 1.33 ppm). Ratio of signal amplitude of each metabolite versus Cr signal was calculated. Results were compared to cortical 1HMRS data of 20 age-matched healthy subjects. Multislice ASL-PI was used to measure CBF in 6 patients. CBF measurement was obtained using single-shot, GE-EPI images with FOV = 24 cm × 15 cm and acquisition matrix of 64 × 40, resulting in an in-plane resolution of 3.75 mm. CBF values have been compared with those obtained in 46 healthy subjects (age ranging from 4 to 76 years). DWI was performed in 5 patients, using an interleaved single-shot pulsed field gradient spin-echo sequence described by Stejskal and Tanner. The diffusion tensor (DTI) has been measured from seven MR images, the first one with bvalue ? 0 and the other six with a bvalue = 1000 sec/mm2 and diffusion gradient applied along the noncollinear directions (1,0,1), (-1,0,1), (0,1,1), (0,1,-1), (1,-1,0), (-1,1,0). The diffusion weighted images (TR = 8000 ms, FOV = 24 cm × 24 cm, matrix = 128 × 128, slice thickness 5 mm) have been repeated four times to improve signal to noise ratio and processed by a Matlab 5.12 code to solve analytically Dij values and to calculate the Trace, VR, FA and LI maps. 1H MRS acquired on CT presented a metabolic profile characterized by a marked increase of mI, a decrease of NAA and normal Cho. Lac was never detected. On the contrary the suspected GCA demonstrated Cho signal increase. In 4 patients ASL-PI demonstrated a marked CBF reduction in cortical regions corresponding with MRI-FLAIR confirmed locations of cortical tubers (15/28 ml/100g/min). Three of these studies revealed also isolated cortical hyperperfusion (160/198 ml/100g/min) corresponding to normal MRI in two cases and to a small cortical dysplasia in one. All of these patients were epileptics. Global CBF was significantly reduced in two patients without any focal cortical flow abnormalities. Both patients were not affected by epilepsy and MRI demonstrated many small and scattered cortical lesions. Of little use turned out DWI and DTI, since TS lesions demonstrated similar diffusion values compared to other type of glial lesions. Among the techniques here evaluated, 1HMRS and ASL-PI have revealed interesting results for a deeper comprehension of TSC. 1H MRS increases the diagnostic confidence in those cases presenting solitary cortical-subcortical lesions and allows a non-invasive longitudinal evaluation of the potential biological transformation of SEN into GCA. CBF hypoperfusion in ASL-PI is in agreement with SPECT and PET studies of TSC, confirming therefore that cortical dysplasias are brain areas metabolically depressed and functionally inert. Focal cortical hyperperfusion detected in three cases could be related to epileptogenic foci. This hypothesis need to be further investigated by means of multimodality functional neuroimaging (MRI, ASL-PI, PET and EEG) in order to test the ASL-PI capability of visualizing the epileptogenic laterality and of identification of the trigger epileptic foci.
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Kasaeyan Naeini, Emad, Ajan Subramanian, Michael-David Calderon, Kai Zheng, Nikil Dutt, Pasi Liljeberg, Sanna Salantera, Ariana M. Nelson, and Amir M. Rahmani. "Pain Recognition With Electrocardiographic Features in Postoperative Patients: Method Validation Study." Journal of Medical Internet Research 23, no. 5 (May 28, 2021): e25079. http://dx.doi.org/10.2196/25079.
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Background There is a strong demand for an accurate and objective means of assessing acute pain among hospitalized patients to help clinicians provide pain medications at a proper dosage and in a timely manner. Heart rate variability (HRV) comprises changes in the time intervals between consecutive heartbeats, which can be measured through acquisition and interpretation of electrocardiography (ECG) captured from bedside monitors or wearable devices. As increased sympathetic activity affects the HRV, an index of autonomic regulation of heart rate, ultra–short-term HRV analysis can provide a reliable source of information for acute pain monitoring. In this study, widely used HRV time and frequency domain measurements are used in acute pain assessments among postoperative patients. The existing approaches have only focused on stimulated pain in healthy subjects, whereas, to the best of our knowledge, there is no work in the literature building models using real pain data and on postoperative patients. Objective The objective of our study was to develop and evaluate an automatic and adaptable pain assessment algorithm based on ECG features for assessing acute pain in postoperative patients likely experiencing mild to moderate pain. Methods The study used a prospective observational design. The sample consisted of 25 patient participants aged 18 to 65 years. In part 1 of the study, a transcutaneous electrical nerve stimulation unit was employed to obtain baseline discomfort thresholds for the patients. In part 2, a multichannel biosignal acquisition device was used as patients were engaging in non-noxious activities. At all times, pain intensity was measured using patient self-reports based on the Numerical Rating Scale. A weak supervision framework was inherited for rapid training data creation. The collected labels were then transformed from 11 intensity levels to 5 intensity levels. Prediction models were developed using 5 different machine learning methods. Mean prediction accuracy was calculated using leave-one-out cross-validation. We compared the performance of these models with the results from a previously published research study. Results Five different machine learning algorithms were applied to perform a binary classification of baseline (BL) versus 4 distinct pain levels (PL1 through PL4). The highest validation accuracy using 3 time domain HRV features from a BioVid research paper for baseline versus any other pain level was achieved by support vector machine (SVM) with 62.72% (BL vs PL4) to 84.14% (BL vs PL2). Similar results were achieved for the top 8 features based on the Gini index using the SVM method, with an accuracy ranging from 63.86% (BL vs PL4) to 84.79% (BL vs PL2). Conclusions We propose a novel pain assessment method for postoperative patients using ECG signal. Weak supervision applied for labeling and feature extraction improves the robustness of the approach. Our results show the viability of using a machine learning algorithm to accurately and objectively assess acute pain among hospitalized patients. International Registered Report Identifier (IRRID) RR2-10.2196/17783
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Yun, Youngsun, Changdon Kee, Jason Rife, Ming Luo, Sam Pullen, and Per Enge. "Detecting RFI Through Integrity Monitoring at a DGPS Reference Station." Journal of Navigation 59, no. 3 (August 23, 2006): 403–22. http://dx.doi.org/10.1017/s0373463306003882.
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Because GPS is a radio navigation system which has a very low power level, it is vulnerable to RFI. Excessive RFI could cause receiver performance degradation, such as degradation of position accuracy, loss of lock and increased acquisition time. After GPS modernization plans introduce dual-frequency civil signals to mitigate ionospheric errors, RFI will remain as one of the dominant threats for differential GPS navigation systems. Examples of safety-critical civil aviation and military missions threatened by RFI include the Local Area Augmentation System (LAAS) and the Joint Precision Approach and Landing System (JPALS). This paper focuses on RFI mitigation through integrity monitoring for a DGPS system like LAAS or JPALS. The mitigation strategy consists of two parts. First, the paper develops a new RFI detection method, using a raw divergence statistic. Second, the paper investigates strategies for maintaining integrity in the case that RFI is detected.To validate the utility of the divergence-based RFI monitor, this paper takes an experimental approach. The experiments assess the performance of the divergence metric and compare it to existing alternatives for RFI detection, such as metrics for Automatic Gain Control (AGC) and carrier-to-noise ratio (C/N0). Generating a monitoring threshold for these statistics proves challenging, because the threshold depends both on the type of RFI threat (e.g. continuous wave, narrow band, wideband, pulsed) and on environmental conditions, such as temperature. As experiments illustrate, the divergence statistic resolves these limitations, as divergence directly estimates ranging source error, independent of the type of RFI threat or the environmental conditions.
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Mackey, John Robert, Benjamin Ecclestone, Deepak Dinakaran, Gilbert Bigras, and Parsin Haji Reza. "H&E-like histology of unstained fresh and formalin fixed breast tissue with Photo Acoustic Remote Sensing (PARS) microscopy." Journal of Clinical Oncology 39, no. 15_suppl (May 20, 2021): e12590-e12590. http://dx.doi.org/10.1200/jco.2021.39.15_suppl.e12590.
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e12590 Background: Approximately 30% of breast cancer patients undergoing breast-conserving surgery (BCS) require re-excision(s) to obtain clear margins, causing delays in adjuvant treatment, poor aesthetic results, and increased infection rates, costs, and patient anxiety. Frozen section pathology assessment (FSA) reduces re-excision rates from 27% to 6%, but FSA extends operative times and has a false negative rate of 17%. Photo-Acoustic Remote Sensing (PARS) is a new laser-based light microscope that permits non-contact cellular resolution imaging of unstained tissues. Methods: We used an ultraviolet reflection-mode PARS microscope to study i) formalin-fixed, paraffin embedded (FFPE) breast tissue blocks, ii) unstained thin sections of FFPE invasive ductal carcinoma and ductal carcinoma in situ, iii) formalin fixed bulk surgical specimens of benign and malignant human breast tissue, and iv) benign and malignant fresh rodent mammary tissue without fixation, processing, or staining. Fresh tissues were imaged after a range of warm ischemic times and across a range of cold ischemic times in neutral phosphate buffered saline at 4°C. For each condition, an ultraviolet laser was used to excite DNA and other cellular components in these samples, and signals were captured using a continuous-wave detection laser. The PARS signal was false-colored to closely replicate traditional hematoxylin and eosin staining. Results: In all fixed tissues, PARS virtual histology images were of diagnostic quality, permitted margin assessment, and analogous to transmission light microscopy of standard hematoxylin and eosin-stained FFPE slides, achieved without tissue sectioning or tissue staining. Furthermore, PARS microscopy also provided cellular level virtual histology images in fresh breast tissue with warm and cold ischemic times ranging from twenty minutes to two hours; these images have no available clinical comparators as non-contact cellular level imaging of unprocessed fresh tissue has not previously been reported. In aggregate, we demonstrate the feasibility of PARS to provide diagnostic and margin assessment images across a range of tissues including formalin fixed and freshly resected, unstained, unprocessed breast tissue. Conclusions: PARS is a new microscope technology addressing the practical needs of intraoperative margin assessment during BCS: i) no requirement for tissue staining, ii) rapid acquisition of hematoxylin and eosin-like images without the requirement for tissue freezing, embedding, or sectioning, iii) diagnostic quality cellular resolution, and iv) assessment of resected bulk tissue margins. In principle, this technology may also permit label-free non-contact intraoperative margin assessment of the surgical cavity. These data support the clinical development and evaluation of PARS microscopic intraoperative assessment of BCS margins.
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Guggeri, Andrés, and Martín Draper. "Large Eddy Simuation of an Onshore Wind Farm with the Actuator Line Model Including Wind Turbine’s Control Below and Above Rated Wind Speed." Energies 12, no. 18 (September 11, 2019): 3508. http://dx.doi.org/10.3390/en12183508.
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As the size of wind turbines increases and their hub heights become higher, which partially explains the vertiginous increase of wind power worldwide in the last decade, the interaction of wind turbines with the atmospheric boundary layer (ABL) and between each other is becoming more complex. There are different approaches to model and compute the aerodynamic loads, and hence the power production, on wind turbines subject to ABL inflow conditions ranging from the classical Blade Element Momentum (BEM) method to Computational Fluid Dynamic (CFD) approaches. Also, modern multi-MW wind turbines have a torque controller and a collective pitch controller to manage power output, particularly in maximizing power production or when it is required to down-regulate their production. In this work the results of a validated numerical method, based on a Large Eddy Simulation-Actuator Line Model framework, was applied to simulate a real 7.7 MNW onshore wind farm on Uruguay under different wind conditions, and hence operational situations are shown with the aim to assess the capability of this approach to model actual wind farm dynamics. A description of the implementation of these controllers in the CFD solver Caffa3d, presenting the methodology applied to obtain the controller parameters, is included. For validation, the simulation results were compared with 1 Hz data obtained from the Supervisory Control and Data Acquisition System of the wind farm, focusing on the temporal evolution of the following variables: Wind velocity, rotor angular speed, pitch angle, and electric power. In addition to this, simulations applying active power control at the wind turbine level are presented under different de-rate signals, both constant and time-varying, and were subject to different wind speed profiles and wind directions where there was interaction between wind turbines and their wakes.
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Leclère, Jérôme, and René Landry. "Galileo E5 Signal Acquisition using Intermediate Coherent Integration Time." Journal of Navigation 72, no. 3 (February 8, 2019): 555–74. http://dx.doi.org/10.1017/s0373463318001054.
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The acquisition of modern Global Navigation Satellite System (GNSS) signals may be difficult due to the presence of a secondary code. Indeed, short coherent integration times should be used without non-coherent integration, which implies a low sensitivity; or long coherent integration times should be used, requiring synchronisation with the secondary code and thus a full correlation, which implies a significant computational burden, especially for signals with long secondary codes such as the Galileo E5 signal. A third option that lies between the previous two is to perform a partial correlation using less than one secondary code period as input, however this is less efficient in terms of complexity than using an entire secondary code period, and the code's autocorrelation properties are completely changed. The authors recently proposed a method based on combining secondary code correlations, allowing the use of intermediate coherent integration times with the possibility to do non-coherent integrations, and the method was successfully applied to the Global Positioning System (GPS) L5 signal. This paper studies the application of the method to the Galileo E5 signal, compares it with the partial correlation method, and discusses the case where less than one secondary code period is used as an input
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Chen, Yun Jun, Xiu Ming Jiang, Gong Yuan Yang, and Yan Cai. "Design and Implementation of Real-Time Audio Transmission System." Advanced Materials Research 433-440 (January 2012): 2887–91. http://dx.doi.org/10.4028/www.scientific.net/amr.433-440.2887.
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Continuous Multi-channel digital audio signals system not only guarantees the continuity of signal acquisition, but has the real-time control ability in the process of signal acquisition. This paper proposes the producer/consumer design pattern which can make program designing quicker, simpler and more efficient. Through the example of continuous sound signal acquisition, the designing idea for the Producer/consumer design pattern is described in details and the design process of this program on the Delphi platform is given. The result shows that the introduction of the producer/consumer design pattern in the use of program design which has serious request in real-time and continuous sound signal acquisition and playing can make the processes response faster and more efficient．
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Yang, Menghuan, Hong Wu, Qiqi Wang, Yingxin Zhao, and Zhiyang Liu. "A BeiDou Signal Acquisition Approach Using Variable Length Data Accumulation Based on Signal Delay and Multiplication." Sensors 20, no. 5 (February 28, 2020): 1309. http://dx.doi.org/10.3390/s20051309.
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The secondary modulation with the Neumann-Hoffman code increases the possibility of bit sign transition. Unlike other GNSS signals, there is no pilot component for synchronization in BeiDou B1/B3 signals, which increases the complexity in acquisition. A previous study has shown that the delay and multiplication (DAM) method is able to eliminate the bit sign transition problem, but it only applies to pretty strong signals. In this paper, a DAM-based BeiDou signal acquisition approach, called variable length data accumulation (VLDA), is proposed to acquire weak satellite signals. Firstly, the performance of DAM method versus the different delays is analyzed. The DAM operation not only eliminates bit sign transition, but it also increases noise power. Secondly, long-term signal is periodically accumulated to improve signal intensity in order to acquire weak signals. While considering the Doppler frequency shift of ranging codes, the signal length must be compensated before accumulating long-term signal. Finally, the fast-Fourier-transform based parallel code phase algorithm are used for acquisition. The simulation results indicate that the proposed VLDA method has better acquisition sensitivity than traditional non-coherent integration method under the same calculation amount. The VLDA method only requires approximately 27.5% of calculations to achieve the same acquisition sensitivity (35 dBHz). What is more, the actual experimental results verify the feasibility of the VLDA method. It can be concluded that the proposed approach is an effective and feasible method for solving the bit sign transition problem.
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Haopeng, ZHANG, CHEN Qingshan, LIU Yang, and LYU Yong. "Time-gated processing of pulse laser ranging echo signal." Journal of Applied Optics 41, no. 6 (2020): 1284–88. http://dx.doi.org/10.5768/jao202041.0607002.
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Sun, Rong Chun, and Yan Piao. "Real-Time Acquisition System of Multi-Channel Signal Based on PCI." Advanced Materials Research 860-863 (December 2013): 2804–7. http://dx.doi.org/10.4028/www.scientific.net/amr.860-863.2804.
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Real time data acquisition system has been paid wild attention to due to exponentially expanding industrial control and measurement. Of many industrial bus, PCI (peripheral component interconnect) bus is a very useful communication protocol available for off-the-shelf PC and high speed acquisition. In the document, an implementation solution of data real-time acquisition based on PCI bus is described. The data acquisition system mainly consists of signal regulation circuit, AD conversion, LVDS transmission, PCI controller. XC3S700 of XILINX FPGA was used as the core chip to bridge and control all parts, which has rich internal resource. Driving program of PCI bus was designed by VC in industrial computer. Test results show that the system can collect multi-channel signal concurrently, steadily and in real time, and has some application value.
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Wong, M., D. Zhang, W. K. Kong, and G. Lu. "Real-time palmprint acquisition system design." IEE Proceedings - Vision, Image, and Signal Processing 152, no. 5 (2005): 527. http://dx.doi.org/10.1049/ip-vis:20049040.
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CD, Raisy, Sharda Vashisth, and Ashok K. Salhan. "Real Time Acquisition of EMG Signal and Head Movement Recognition." International Journal of Computer Applications 73, no. 1 (July 26, 2013): 19–22. http://dx.doi.org/10.5120/12705-9501.
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Perman, William H., Mokhtar H. Gado, Kenneth B. Larson, and Joel S. Perlmutter. "Simultaneous MR Acquisition of Arterial and Brain Signal-Time Curves." Magnetic Resonance in Medicine 28, no. 1 (November 1992): 74–83. http://dx.doi.org/10.1002/mrm.1910280108.
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Rongen, H., V. Hadamschek, and M. Schiek. "Real time data acquisition and online signal processing for magnetoencephalography." IEEE Transactions on Nuclear Science 53, no. 3 (June 2006): 704–8. http://dx.doi.org/10.1109/tns.2006.874802.
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Jeon, Young-Deuk, and Seung-Hoon Lee. "Acquisition time minimisation techniques for high-speed analogue signal processing." Electronics Letters 35, no. 23 (1999): 1990. http://dx.doi.org/10.1049/el:19991378.
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Bezerra, José Paulo Modolo, Sandra Mara Torres Müller, and Mário Mestria. "Development of computational system for short-time biological signal acquisition." Biomedical Signal Processing and Control 64 (February 2021): 102269. http://dx.doi.org/10.1016/j.bspc.2020.102269.
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Liu, Yang, Yong Tie, Shun Na, and Dong Li. "Acoustic Signal Acquisition and Analysis System Based on Digital Signal Processor." Advanced Materials Research 518-523 (May 2012): 1436–41. http://dx.doi.org/10.4028/www.scientific.net/amr.518-523.1436.
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Leak detection and calibration of pipe internal roughness in a water distribution network are significant issue for environment pollution around the world. In recent years the problem of leak detection in pipelines, tanks, and process vessels has been the focus of many man-hours of effort. Acquisition the acoustic signal around the leakage to determine the location and size of leaks is emerging as an important tool. A double acoustic data acquisition and signal processing system based on the TI digital signal processor TMS320VC5410 and analog to digital converter TLC320AD50C is presented in this paper. The system design is introduced, with emphasis on the digital signal processor minimal system and TMS320VC5410 interface circuit which consists of two chips of A/D TLC320AD50C. The software development of the data acquisition and signal analysis is introduced. The system can be used in the application of real-time acoustic signal acquisition and leak location.
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Deng, Zhong Liang, Lu Yin, Yue Xi, Zhong Wei Zhan, Hui Dong, and Guan Yi Wang. "A Fast Acquisition Algorithm for GNSS Multi-System Interoperability Signals." Applied Mechanics and Materials 411-414 (September 2013): 1025–32. http://dx.doi.org/10.4028/www.scientific.net/amm.411-414.1025.
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There are more acquisition cells and long stop time on each cell because of the features of the new GNSS signal systems. So the average acquisition time of the new signals increase much longer than the former one. The new signal features was analyzed at first in this paper, and then the acquisition algorithm of QPSK and MBOC modulated signals was introduced separately. A Multiplexing Channel of Time-Division technique and Multi-frequency aid algorithm was proposed to increase the acquisition speed. This new fast acquisition algorithm significantly reduced the average acquisition time of the new GNSS signal systems.
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Cheng, L. "Signal Interpretation from Low-dosage Acquisition." Methods of Information in Medicine 49, no. 05 (2010): 542–46. http://dx.doi.org/10.3414/me09-02-0029.
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Summary Objectives: This paper focuses on how we could analyze and interpret filtered back-projection reconstructed signals from low-dose computed tomographic (CT) imaging systems. There exists a growing imbalance between dosage reduction and effective signal interpretation. At the same time, low-dose applications are undergoing alarming growth. Methods: This paper interprets filtered back-projection images in low-dose CT systems and details the possible properties of the artifacts. The interpretation leads to design of a new multi-image filtered back-projection approach that allows artifacts to be effectively identified across multiple images. We use this approach as a building block to propose a new reconstruction method that enables effective artifacts reduction and efficient implementation. Results: Experiments with both clinical and simulated low-dose images demonstrate the validity and effectiveness of the proposed approach. Conclusions: This study discusses a new FBP-based reconstruction approach based on signal interpretation from low-dosage acquisition. This method uses multiple filtered back-projection images from projection subsets to provide clues for distinguishing underlying clinical structure from artifacts. A framework is derived for effective signal interpretation and artifacts reduction. It requires no hardware change and a minimum amount of extra software support compared with current CT systems. Clinical and simulated low-dose CT scans demonstrated effectiveness of the proposed method.
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Zhao, Jian Bo. "The Design of CNC Lathe Cutting Force Signal On-Line Monitoring." Applied Mechanics and Materials 155-156 (February 2012): 526–30. http://dx.doi.org/10.4028/www.scientific.net/amm.155-156.526.
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The main task is to study the CNC lathe cutting force signal on-line monitoring system design, it mainly includes the cutting force signal acquisition, real-time monitoring and subsequent processing and analysis. Cutting force signal acquisition is the use of Kistler piezoelectric sensor signal, converted into voltage signal, and through the data acquisition board, to convert analog signals into digital signals, input to the computer, the computer real-time monitoring of machining process. Signal processing is to the acquisition of signal processing and analysis, to obtain the correct dynamic cutting force signal, to verify the stability and reliability of the whole monitoring system.
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Zhang, Yan Jun, Li Xia Di, Jing Cui, and Jing Yang. "Variable Multi-Channel High Frequency Signal Acquisition System." Advanced Materials Research 798-799 (September 2013): 515–19. http://dx.doi.org/10.4028/www.scientific.net/amr.798-799.515.
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A flexible system to multi-channel high frequency signal acquisition and transmission was designed. The system took FPGA as the center control logic unit. It could realize real-time acquisition, conditioning, modulus conversion to multi-channel high frequency signal and sent the converted digital signal to the storage device through FIFO. The system could also realize the real-time monitoring, data unpacking and analysis to storaged data by using computer software. FPGA software design adopted VHDL language. The experiment results show that this data acquisition and transmission system is stable and accurate.
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De Lima, Olivar A. L., and Hédison K. Sato. "APPLICATION OF FREQUENCY AND TIME DOMAIN INDUCED POLARIZATION – RESISTIVITY EFFECTS FOR EXPLORING AQUIFER AND HYDROCARBON RESERVOIRS IN BAHIA, BRAZIL." Brazilian Journal of Geophysics 37, no. 4 (December 1, 2019): 545. http://dx.doi.org/10.22564/rbgf.v37i4.2030.
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ABSTRACT. Two field surveys using the induced polarization (IP) – resistivity method, are presented as an effective tool to evaluate aquifer and hydrocarbon reservoirs at shallow depths. First, the electrochemical mechanisms responsible for generating IP effects in reservoir rocks are reviewed. Then, theoretical developments are proposed to reduce the inductive electromagnetic coupling from the underground IP effects, and to compute three fundamental electrical parameters, namely the apparent DC-resistivity, the apparent chargeability and relaxation time, both for frequency (FD) and time-domain (TD) data. These parameters are attributed to average representative volumes of the subsurface geology, which depends on the electrode array and its characteristic depth of investigation. The studied structure includes: an upper fresh-water sandstone aquifer of 60m average thickness; overlaying a 70m thick, prismatic sandstone oil-reservoir, sandwiched between shale sequences and laterally confined by intersecting normal faults. The data acquisitions were made using dipole-dipole electrode arrays, with lengths a of 50 and 100 m, and separations na, with n ranging from 1 to 12 (FD), and 1 to 6 (TD). The 2-D inverted pseudo-sections exhibit small distortions, attributed to differences in resolution, terrain effects and signal-to-noise ratios, but are consistent in outlining the following features: i) the detection of an upper resistive low-IP layer, representing a water-table aquifer; ii) a distinct electrical anomaly, related to the western bounding fault zone, depicted as a conductive chimney bordered by high resistive halos; iii) the separation of different geo-electrical units within the shale sequence sealing the reservoir; and iv) the delineation of the top of oil reservoir, defined by a slight increase in resistivity and by high IP values, at and above the oil reservoir.Keywords: electrical resistivity, induced polarization, aquifers, oil reservoirs.RESUMO. Levantamentos geofísicos usando resistividade e polarização induzida (PI) são apresentados como ferramenta eficaz para avaliar aquíferos e reservatórios petrolíferos em profundidades rasas. Primeiro, faz-se uma revisão dos mecanismos eletroquímicos geradores de PI em rochas reservatórios. Em seguida, propõem-se tratamentos teóricos para separar o acoplamento eletromagnético dos efeitos puros da PI subterrânea e calcular três parâmetros aparentes fundamentais: resistividade (ρ0,a), cargabilidade (mw,a) e tempo de relação (τ w,a), tanto no domínio da frequência (FD) quanto do tempo (TD). Esses parâmetros são atribuídos a centros volumétricos representativos da geologia, que dependem do arranjo de eletrodos e de suas profundidades de investigação. A estrutura estudada inclui: um aquífero arenoso superior, com 60m de espessura; sobreposto a um reservatório petrolífero prismático de arenitos, com 70m de espessura, intercalado entre sequências argilosas, e lateralmente confinado por falhas normais intercruzadas. Os dados foram adquiridos com arranjos dipolo-dipolo usando distâncias entre eletrodos de 50 e 100 m, e separações na, com n variando de 1 a 12 (FD) e 1 a 6 (TD). As seções 2-D invertidas exibem pequenas distorções, atribuídas a diferenças de resolução, efeitos de terreno e razão sinal-ruído, mas consistentes na identificação dos seguintes aspectos: (i) detecção de camada superior resistiva e baixo PI, representando o aquífero freático; (ii) anomalia elétrica relacionada à falha do limite ocidental, revelada como uma chaminé condutora com halos de maior resistividade; (iii) separação de duas unidades geoelétricas na sequência dos folhelhos selantes do reservatório; e (iv) delineamento do topo do reservatório de óleo, definido por um ligeiro aumento na resistividade e por altos valores de PI no e acima do reservatório.Palavras-chave: resistividade elétrica, polarização induzida, aquíferos, reservatórios.