scholarly journals A Tri-Satellite Interference Source Localization Method for Eliminating Mirrored Location

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4483
Author(s):  
Lihuan Huo ◽  
Rulong Bai ◽  
Man Jiang ◽  
Bing Chen ◽  
Jianfeng Chen ◽  
...  
Keyword(s):  
Measurement Errors ◽  
Satellite Communication ◽  
Simulation Experiments ◽  
Time Difference Of Arrival ◽  
Initial Location ◽  
Single Moment ◽  
Large Measurement ◽  
Newton Iteration Method ◽  
Intersection Points ◽  
Cross Ambiguity Function

With the increase in satellite communication interference, the tri-satellite time difference of arrival (TDOA) localization technique, which is an effective method to determine the location of the interference using sensors or antennas, has been developed rapidly. The location of the interference source is determined through the intersection of the TDOA lines of position (LOP). However, when the two TDOA LOP have two mirrored intersection points, it is theoretically difficult to determine the real location. Aiming at this problem, a method for eliminating mirrored location based on multiple moment TDOA is proposed in this paper. First, the TDOA results are measured at multiple moments using the cross-ambiguity function (CAF), and the localization equation set is established based on the World Geodetic System (WGS)-84 earth ellipsoid model. Then, the initial location result can be obtained by solving the equation set through the Newton iteration method. Finally, the high-precision location result after eliminating the mirrored location is obtained after the single moment localization based on the initial location. Simulation experiments and real measured data processing results verify the effectiveness of the proposed method. It still has good robustness under the condition of large measurement errors and deviations from the prior initial values.

scholarly journals Physical and chemical parameters impact on eosin spectral determinations

2010 ◽  
Vol 29 (1) ◽  
pp. 51
Author(s):  
Liljana Kola
Keyword(s):  
Fluorescence Intensity ◽  
Water Samples ◽  
Measurement Errors ◽  
Fluorescent Dyes ◽  
Water System ◽  
Chemical Properties ◽  
Photochemical Decomposition ◽  
Large Measurement ◽  
Physical And Chemical ◽  
And Chemical Properties

The fluorescence ability of Eosin enables its using as an artificial tracer in the water system studies. The problem deals with the application of Eosin to trace and determine water movements within the karstic system and under ground waters. The fluorescence intensity of fluorescent dyes in water samples depends on their physical and chemical properties, such as pH, temperature, presence of oxidants, etc. Besides that, the UV radiation may induce photochemical decomposition of Eosin which can cause large measurement errors. This paper presents the taken results studying the influence of these factors on Eosin fluorescence intensity using the concentration and synchron scan methods. The method we have elaborated for this purpose made it possible to optimize procedures we use to analyze water samples for the presence of Eosin and measure its content, even in trace levels by the means of the Perkin Elmer LS 55 Luminescence Spectrometer.

Resonance Suppression on Nanoscale Viscoelasticity Measurement

2012 ◽  
Vol 528 ◽  
pp. 75-79
Author(s):  
Ping Xie ◽  
Lei Zhang ◽  
Qing Ze Zou
Keyword(s):  
Measurement Errors ◽  
Measurement Data ◽  
Notch Filter ◽  
Soft Materials ◽  
Resonance Peak ◽  
Hertz Contact ◽  
Resonance Effects ◽  
Atomic Force ◽  
Complex Compliance ◽  
Large Measurement

During the broadband viscoelasticity measurement process, when the frequency of the excitation force become high relative to the resonant frequency or the bandwidth of the instrument dynamics, the adverse instrument dynamics is motivated, which causes the cantilever resonance and generates large measurement errors in the measurement data. To solve this problem, an approach to suppress the cantilever resonance on the broadband viscoelasticity measurement is proposed. Firstly, Atomic force microscope (AFM) system dynamic is analyzed by using a dynamic signal analyzer (DSA) in the z-axis. And a notch filter is designed as a prefilter of the AFM system to filter the input drive voltage in order to offset the resonance peak in the AFM model. Secondly, an adaptive filter based on LMS is designed to further eliminate the residual cantilever resonance effects on the complex compliance of soft materials, referring to the Hertz contact model. Finally, the proposed approach is illustrated by implementing it to remove the cantilever resonance effects on the broadband viscoelasticity measurement of a polydimethylsiloxane (PDMS) sample using AFM.

scholarly journals Measuring and using information gained by observing diffraction data

2020 ◽  
Vol 76 (3) ◽  
pp. 238-247 ◽  
Author(s):  
Randy J. Read ◽  
Robert D. Oeffner ◽  
Airlie J. McCoy
Keyword(s):  
Probability Distribution ◽  
Measurement Errors ◽  
Posterior Probability ◽  
Information Gain ◽  
Current Trend ◽  
Posterior Probability Distribution ◽  
New Methods ◽  
Leibler Divergence ◽  
Large Measurement ◽  
A Current

The information gained by making a measurement, termed the Kullback–Leibler divergence, assesses how much more precisely the true quantity is known after the measurement was made (the posterior probability distribution) than before (the prior probability distribution). It provides an upper bound for the contribution that an observation can make to the total likelihood score in likelihood-based crystallographic algorithms. This makes information gain a natural criterion for deciding which data can legitimately be omitted from likelihood calculations. Many existing methods use an approximation for the effects of measurement error that breaks down for very weak and poorly measured data. For such methods a different (higher) information threshold is appropriate compared with methods that account well for even large measurement errors. Concerns are raised about a current trend to deposit data that have been corrected for anisotropy, sharpened and pruned without including the original unaltered measurements. If not checked, this trend will have serious consequences for the reuse of deposited data by those who hope to repeat calculations using improved new methods.

Research of On-Line Large-Size Forging Measurement System Based on LabVIEW

2012 ◽  
Vol 430-432 ◽  
pp. 1577-1580
Author(s):  
Xian Ling Zhao ◽  
Jian Sheng Liu
Keyword(s):  
Measurement Error ◽  
Laser Beam ◽  
Measurement Errors ◽  
Three Dimensional ◽  
Automatic Measurement ◽  
Manual Measurement ◽  
Large Size ◽  
On Line ◽  
Large Measurement ◽  
Time Changes

Forging temperature is usually around 1000°C in free forging scene. Manual measurement leads to large measurement errors. Adopting the non-contact 3D scanning technology, make the laser beam sweep across the forging surface to get three-dimensional coordinates of the points on the forging surface in space. Neighboring scan points separate by less than 0.25mm. The measurement error is less than 6mm. The coordinate,s data are sent to the LabVIEW procedure. The procedure analyzes the coordinates to calculate the size of the large-size forging to realize automatic measurement of the forgings. The procedure can also reconstruct the image of the large-size forging. These make us detect the real-time changes of the forging far from the free forging scene.

scholarly journals Cruciferous vegetables and colo-rectal cancer

2006 ◽  
Vol 65 (1) ◽  
pp. 135-144 ◽  
Author(s):  
Anthony Lynn ◽  
Andrew Collins ◽  
Zoë Fuller ◽  
Kevin Hillman ◽  
Brian Ratcliffe
Keyword(s):  
Rectal Cancer ◽  
Bioactive Compounds ◽  
Measurement Errors ◽  
Vegetable Intake ◽  
Biological Effects ◽  
Epidemiological Studies ◽  
Cruciferous Vegetables ◽  
Cruciferous Vegetable ◽  
Chemically Induced ◽  
Large Measurement

Cruciferous vegetables have been studied extensively for their chemoprotective effects. Although they contain many bioactive compounds, the anti-carcinogenic actions of cruciferous vegetables are commonly attributed to their content of glucosinolates. Glucosinolates are relatively biologically inert but can be hydrolysed to a range of bioactive compounds such as isothiocyanates (ITC) and indoles by the plant-based enzyme myrosinase, or less efficiently by the colonic microflora. A number of mechanisms whereby ITC and indoles may protect against colo-rectal cancer have been identified. In experimental animals cruciferous vegetables have been shown to inhibit chemically-induced colon cancer. However, the results of recent epidemiological cohort studies have been inconsistent and this disparity may reflect a lack of sensitivity of such studies. Possible explanations for the failure of epidemiological studies to detect an effect include: assessment of cruciferous vegetable intake by methods that are subject to large measurement errors; the interaction between diet and genotype has not been considered: the effect that post-harvest treatments may have on biological effects of cruciferous vegetables has not been taken into account.

scholarly journals Estimation Under Mode Effects and Proxy Surveys, Accounting for Non-ignorable Nonresponse

Sankhya A ◽  
2021 ◽  
Author(s):  
Danny Pfeffermann ◽  
Arie Preminger
Keyword(s):  
Measurement Errors ◽  
Survey Sampling ◽  
Household Surveys ◽  
Personal Interview ◽  
Simulation Experiments ◽  
Mode Effects ◽  
Sample Data ◽  
Point Estimators ◽  
Internet Telephone ◽  
True Population

AbstractWe propose a new, model-based methodology to address two major problems in survey sampling: The first problem is known as mode effects, under which responses of sampled units possibly depend on the mode of response, whether by internet, telephone, personal interview, etc. The second problem is of proxy surveys, whereby sampled units respond not only about themselves but also for other sampled. For example, in many familiar household surveys, one member of the household provides information for all other members, possibly with measurement errors. Ignoring the existence of mode effects and/or possible measurement errors in proxy surveys could result in possible bias in point estimators and subsequent inference. Our approach accounts also for nonignorable nonresponse. We illustrate the proposed methodology by use of simulation experiments and real sample data, with known true population values.

scholarly journals Location Estimation of Beacon in MEOSAR System

2012 ◽  
pp. 265-271
Author(s):  
Sowmya C. H ◽  
H. C. Srinivasaiah
Keyword(s):  
Location Estimation ◽  
Search And Rescue ◽  
Frequency Difference ◽  
Common Method ◽  
Simple Method ◽  
Time Difference Of Arrival ◽  
Location Data ◽  
Rescue System ◽  
Cross Ambiguity Function ◽  
Local User

This paper describes the satellite aided search and rescue system that provides services to save the lives at the distress or emergency regions. COSPAS - SARSAT is a satellite-based system designed to provide distress alert and location data to facilitate SAR operations. The ground receiver named as Local User Terminals (LUTs) is in charge of processing the incoming signal and determining the beacon position via Frequency Difference of Arrival (FDOA) and Time Difference of Arrival (TDOA) technique. A common method of calculating TDOA and FDOA is the Cross Ambiguity Function (CAF). This paper proposes the implementation of CAF map method, which is a simple method that reduces the processing complexity over CAF method and also as the ability to locate several beacons that eliminates the false location of beacons.

scholarly journals Experimental Study of the Effects of Flow Discharge, Diameter, and Depth on Shear Stress in a Rectangular Channel with Rigid Unsubmerged Vegetation

2019 ◽  
Vol 9 (2) ◽  
pp. 155-160
Author(s):  
Foad Maturi ◽  
Mehdi Behdarvandi Askar
Keyword(s):  
Shear Stress ◽  
Measurement Errors ◽  
Stress Measurement ◽  
Rectangular Channel ◽  
Correlation Coefficients ◽  
Critical Parameters ◽  
Vegetation Density ◽  
Flow Discharge ◽  
Large Measurement ◽  
A New Technique

Abstract Shear stress is one of the most critical parameters in hydraulic and coastal engineering, which is often measured indirectly. Since there is no instrument to measure this parameter directly and given that it is usually calculated by measuring other parameters such as velocity and pressure and using some equations, shear stress measurement is often accompanied with large measurement errors. In this study, a new technique and direct measurement using physical modeling in a hydraulic knife-edge flume and load cell were employed to measure the shear stress in a rectangular channel with rigid unsubmerged vegetation with Dv= 20, 25, and 32mm in Q=25 and 30 Lit/S and y=10, 12, 17, and 20 cm. The results indicate that the shear stress and the dimensionless {{{\tau _0}} \over \tau } ratio decrease in a constant flow discharge with increasing the flow depth. It was also shown that the shear stress would be enhanced with an increase in vegetation diameter due to increasing vegetation density against flow. According to dimensionless ratios of {{{\tau _0}} \over \tau } and {{{D_v}} \over y} in the graphs and considering the trend lines with appropriate correlation coefficients, some equations were presented to calculate the shear stress in the concerned range.

scholarly journals ADMISSIBLE CLUSTERING OF AGGREGATOR COMPONENTS: A NECESSARY AND SUFFICIENT STOCHASTIC SEMINONPARAMETRIC TEST FOR WEAK SEPARABILITY

2009 ◽  
Vol 13 (S2) ◽  
pp. 317-334 ◽  
Author(s):  
William A. Barnett ◽  
Philippe de Peretti
Keyword(s):  
Measurement Errors ◽  
Statistical Tests ◽  
Index Number ◽  
Admissibility Condition ◽  
Weak Separability ◽  
New Class ◽  
Index Number Theory ◽  
Monte Carlo Studies ◽  
Large Measurement ◽  
Necessary And Sufficient

In aggregation theory, the admissibility condition for clustering components to be aggregated is blockwise weak separability, which also is the condition needed to separate out sectors of the economy. Although weak separability is thereby of central importance in aggregation and index number theory and in econometrics, prior attempts to produce statistical tests of weak separability have performed poorly in Monte Carlo studies. This paper introduces a new class of weak separability tests, which is seminonparametric. Such tests are both based on a necessary and sufficient condition and are fully stochastic, allowing to take into account measurement error. Simulations show that the tests perform well, even for large measurement errors.

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