Smoothing spectral gamma logs: A simple but effective technique

Geophysics ◽  
1987 ◽  
Vol 52 (3) ◽  
pp. 363-367 ◽  
Author(s):  
Gary L. Mathis
Keyword(s):  
Real Time ◽  
Kalman Filtering ◽  
Adaptive Filter ◽  
Gamma Ray ◽  
Error Function ◽  
The Other ◽  
Weighted Averaging ◽  
Effective Technique ◽  
Abrupt Changes ◽  
Counting Statistics

Spectral gamma‐ray logs suffer from unusually poor counting statistics because of the extremely low counting rates used to compute the concentrations of potassium (K), uranium (U), and thorium (T). Filtering is therefore a prerequisite to interpretation. Kalman filtering has been suggested, but this approach is complex and involves uncertain assumptions. Simple weighted averaging, on the other hand, fails to take into account abrupt changes that can occur in geologic response. Effective filtering of real logging data is possible, however, by a simple adaptive filter which uses the total gamma responses of a gamma‐ray tool to compute filter weights based on the error function. This filter is mathematically and computationally simple to implement for real time or postprocessing of spectral gamma logs.

A covariance shaping filtering method for tightly-coupled MIMU/GNSS of UAV

2019 ◽  
Vol 91 (10) ◽  
pp. 1257-1267 ◽  
Author(s):  
Bin Liu ◽  
Jiangtao Xu ◽  
Bangsheng Fu ◽  
Yong Hao ◽  
Tianyu An
Keyword(s):  
Real Time ◽  
Kalman Filtering ◽  
Adaptive Filter ◽  
Dynamic Environments ◽  
Content Type ◽  
Filtering Method ◽  
Time Performance ◽  
Dual Channel ◽  
Tightly Coupled ◽  
Parallel Filter

Purpose Regarding the important roles of accuracy and robustness of tightly-coupled micro inertial measurement unit (MIMU)/global navigation satellite system (GNSS) for unmanned aerial vehicle (UAV). This study aims to explore the efficient method to improve the real-time performance of the sensors. Design/methodology/approach A covariance shaping adaptive Kalman filtering method is developed. For optimal performance of multiple gyros and accelerometers, a distribution coefficient of precision is defined and the data fusion least square method is applied with fault detection and identification using the singular value decomposition. A dual channel parallel filter scheme with a covariance shaping adaptive filter is proposed. Findings Hardware-in-the-loop numerical simulation was adopted, the results indicate that the gain of the covariance shaping adaptive filter is self-tuning by changing covariance weighting factor, which is calculated by minimizing the cost function of Frobenius norm. With the improved method, the positioning accuracy with tightly-coupled MIMU/GNSS of the adaptive Kalman filter is increased obviously. Practical implications The method of covariance shaping adaptive Kalman filtering is efficient to improve the accuracy and robustness of tightly-coupled MIMU/GNSS for UAV in complex and dynamic environments and has great value for engineering applications. Originality/value A covariance shaping adaptive Kalman filtering method is presented and a novel dual channel parallel filter scheme with a covariance shaping adaptive filter is proposed, to improve the real-time performance in complex and dynamic environments.

The Impact of Filtering on Sea and Air Operations

1983 ◽  
Vol 36 (1) ◽  
pp. 74-80
Author(s):  
M. G. Pearson
Keyword(s):  
Real Time ◽  
Kalman Filtering ◽  
The Other ◽  
Estimation Methods ◽  
Weighted Mean ◽  
Modern Approach ◽  
On Line ◽  
Computer Based ◽  
And Control ◽  
The Impact

Estimation methods and filtering techniques are nowadays an integral part of any computer-based navigation system. The purpose of these techniques is to provide an estimate of required variables which is sufficiently accurate for real-time command and control purposes. Repeatability, which is important for so many applications, is deemed to be a by-product of the estimation process. For this requirement it is not strictly necessary for the process to be accurate, it is sufficient if it is only consistent; these are closely linked but one does not imply the other. The modern approach is to minimize the variance of the noisy observations or the sum of the squares of the residuals, and the methods available for doing this are increasingly refined. The impression given in the literature (and it is extensive) is that data processing can somehow compensate for the shortcomings of the basic sensors with respect to the operation being considered. Within certain limits this is true, but the real reason for the sudden surge of Kalman filtering for real-time on-line applications was the relative simplicity of the computational process. In a way, Kalman filtering has done for estimation theory what the Fast Fourier Transform has done for spectral analysis.The concept is simple enough to state. It consists of combining two independent estimates of a variable to form a weighted mean. One of these estimates is a forecast and the other is the current measurement.

Real-time signal processing in field programmable gate array based digital gamma-ray spectrometer

2020 ◽  
Vol 91 (10) ◽  
pp. 104707
Author(s):  
Yinyu Liu ◽  
Hao Xiong ◽  
Chunhui Dong ◽  
Chaoyang Zhao ◽  
Quanfeng Zhou ◽  
...  
Keyword(s):  
Signal Processing ◽  
Real Time ◽  
Field Programmable Gate Array ◽  
Gamma Ray ◽  
Time Signal ◽  
Gamma Ray Spectrometer ◽  
Field Programmable ◽  
Gate Array ◽  
Real Time Signal Processing

scholarly journals Evaluating Latency in Multiprocessing Embedded Systems for the Smart Grid

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3322
Author(s):  
Sara Alonso ◽  
Jesús Lázaro ◽  
Jaime Jiménez ◽  
Unai Bidarte ◽  
Leire Muguira
Keyword(s):  
Operating System ◽  
Smart Grid ◽  
Real Time ◽  
Processing System ◽  
The Other ◽  
Programmable Logic ◽  
Detailed Characterization ◽  
Timing Constraint ◽  
Time Part

Smart grid endpoints need to use two environments within a processing system (PS), one with a Linux-type operating system (OS) using the Arm Cortex-A53 cores for management tasks, and the other with a standalone execution or a real-time OS using the Arm Cortex-R5 cores. The Xen hypervisor and the OpenAMP framework allow this, but they may introduce a delay in the system, and some messages in the smart grid need a latency lower than 3 ms. In this paper, the Linux thread latencies are characterized by the Cyclictest tool. It is shown that when Xen hypervisor is used, this scenario is not suitable for the smart grid as it does not meet the 3 ms timing constraint. Then, standalone execution as the real-time part is evaluated, measuring the delay to handle an interrupt created in programmable logic (PL). The standalone application was run in A53 and R5 cores, with Xen hypervisor and OpenAMP framework. These scenarios all met the 3 ms constraint. The main contribution of the present work is the detailed characterization of each real-time execution, in order to facilitate selecting the most suitable one for each application.

scholarly journals Simple, cost-effective technique for portable digital eletrocorticography

2000 ◽  
Vol 58 (2B) ◽  
pp. 424-427 ◽  
Author(s):  
PAULO R. M. DE BITTENCOURT ◽  
MARCOS C. SANDMANN ◽  
MARLUS S. MORO ◽  
JOÃO C. DE ARAÚJO
Keyword(s):  
Real Time ◽  
Epilepsy Surgery ◽  
Vascular Malformations ◽  
Cost Effective ◽  
New Method ◽  
Cortical Lesions ◽  
Effective Technique ◽  
Seizure Disorders ◽  
Operational Costs ◽  
Cost Effective Technique

We revised 16 patients submitted to epilepsy surgery using a new method of digital, real-time, portable electrocorticography. Patients were operated upon over a period of 28 months. There were no complications. The exam was useful in 13 cases. The low installation and operational costs, the reliability and simplicity of the method, indicate it may be useful for defining the epileptogenic regions in a variety of circumnstances, including surgery for tumors, vascular malformations, and other cortical lesions associated with seizure disorders.

scholarly journals Neutrino Astronomy with IceCube

2016 ◽  
Vol 12 (S324) ◽  
pp. 322-329
Author(s):  
Kevin J. Meagher
Keyword(s):  
Real Time ◽  
Gamma Ray ◽  
Galactic Plane ◽  
Galactic Nuclei ◽  
High Energy ◽  
Glacial Ice ◽  
Astrophysical Neutrinos ◽  
Charged Secondary ◽  
Neutrino Astronomy ◽  
The Antarctic

AbstractThe IceCube Neutrino Observatory is a cubic kilometer neutrino telescope located at the Geographic South Pole. Cherenkov radiation emitted by charged secondary particles from neutrino interactions is observed by IceCube using an array of 5160 photomultiplier tubes embedded between a depth of 1.5 km to 2.5 km in the Antarctic glacial ice. The detection of astrophysical neutrinos is a primary goal of IceCube and has now been realized with the discovery of a diffuse, high-energy flux consisting of neutrino events from tens of TeV up to several PeV. Many analyses have been performed to identify the source of these neutrinos: correlations with active galactic nuclei, gamma-ray bursts, and the galactic plane. IceCube also conducts multi-messenger campaigns to alert other observatories of possible neutrino transients in real-time. However, the source of these neutrinos remains elusive as no corresponding electromagnetic counterparts have been identified. This proceeding will give an overview of the detection principles of IceCube, the properties of the observed astrophysical neutrinos, the search for corresponding sources (including real-time searches), and plans for a next-generation neutrino detector, IceCube–Gen2.

scholarly journals Inter-laboratory comparison of three different real-time PCR assays for the detection of Pneumocystis jiroveci in bronchoalveolar lavage fluid samples

2006 ◽  
Vol 55 (9) ◽  
pp. 1229-1235 ◽  
Author(s):  
Catharina F. M. Linssen ◽  
Jan A. Jacobs ◽  
Pieter Beckers ◽  
Kate E. Templeton ◽  
Judith Bakkers ◽  
...  
Keyword(s):  
Bronchoalveolar Lavage ◽  
Real Time ◽  
Real Time Pcr ◽  
Bronchoalveolar Lavage Fluid ◽  
Medical Center ◽  
Tertiary Care ◽  
Lavage Fluid ◽  
The Other ◽  
Pneumocystis Jiroveci ◽  
Pcr Assays

Pneumocystis jiroveci pneumonia (PCP) is an opportunistic infection affecting immunocompromised patients. While conventional diagnosis of PCP by microscopy is cumbersome, the use of PCR to diagnose PCP has great potential. Nevertheless, inter-laboratory validation and standardization of PCR assays is lacking. The aim of this study was to evaluate the inter-laboratory agreement of three independently developed real-time PCR assays for the detection of P. jiroveci in bronchoalveolar lavage fluid samples. Therefore, 124 samples were collected in three tertiary care laboratories (Leiden University Medical Center, Maastricht Infection Center and Radboud University Nijmegen Medical Centre) and were tested by both microscopy and real-time PCR. Of 41 samples positive for P. jiroveci by microscopy, 40 were positive in all three PCR assays. The remaining sample was positive in a single assay only. Out of 83 microscopy-negative samples, 69 were negative in all three PCR assays. The other 14 samples were found positive, either in all three assays (n=5), in two (n=2) or in one of the assays (n=7). The data demonstrate high inter-laboratory agreement among real-time PCR assays for the detection of P. jiroveci.

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