scholarly journals Empirical analysis and modeling of Argos Doppler location errors in Romania

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6362 ◽  
Author(s):  
Laurentiu Rozylowicz ◽  
Florian P. Bodescu ◽  
Cristiana M. Ciocanea ◽  
Athanasios A. Gavrilidis ◽  
Steluta Manolache ◽  
...  
Keyword(s):  
High Speed ◽  
Spatial Ecology ◽  
Local Environment ◽  
Quality Data ◽  
Aquatic Animal ◽  
Location Errors ◽  
Wildlife Tracking ◽  
Doppler Data ◽  
Proper Filter ◽  
And Behavior

Background Advances in wildlife tracking technology have allowed researchers to understand the spatial ecology of many terrestrial and aquatic animal species. Argos Doppler is a technology that is widely used for wildlife tracking owing to the small size and low weight of the Argos transmitters. This allows them to be fitted to small-bodied species. The longer lifespan of the Argos units in comparison to units outfitted with miniaturized global positioning system (GPS) technology has also recommended their use. In practice, large Argos location errors often occur due to communication conditions such as transmitter settings, local environment, and the behavior of the tracked individual. Methods Considering the geographic specificity of errors and the lack of benchmark studies in Eastern Europe, the research objectives were: (1) to evaluate the accuracy of Argos Doppler technology under various environmental conditions in Romania, (2) to investigate the effectiveness of straightforward destructive filters for improving Argos Doppler data quality, and (3) to provide guidelines for processing Argos Doppler wildlife monitoring data. The errors associated with Argos locations in four geographic locations in Romania were assessed during static, low-speed and high-speed tests. The effectiveness of the Douglas Argos distance angle filter algorithm was then evaluated to ascertain its effect on the minimization of localization errors. Results Argos locations received in the tests had larger associated horizontal errors than those indicated by the operator of the Argos system, including under ideal reception conditions. Positional errors were similar to those obtained in other studies outside of Europe. The errors were anisotropic, with larger longitudinal errors for the vast majority of the data. Errors were mostly related to speed of the Argos transmitter at the time of reception, but other factors such as topographical conditions and orientation of antenna at the time of the transmission also contributed to receiving low-quality data. The Douglas Argos filter successfully excluded the largest errors while retaining a large amount of data when the threshold was set to the local scale (two km). Discussion Filter selection requires knowledge about the movement patterns and behavior of the species of interest, and the parametrization of the selected filter typically requires a trial and error approach. Selecting the proper filter reduces the errors while retaining a large amount of data. However, the post-processed data typically includes large positional errors; thus, we recommend incorporating Argos error metrics (e.g., error ellipse) or use complex modeling approaches when working with filtered data.

scholarly journals Empirical Analysis and Modeling of Argos Doppler Location Errors in Romania

2018 ◽  
Author(s):  
Laurentiu Rozylowicz ◽  
Florian P. Bodescu ◽  
Cristiana M. Ciocanea ◽  
Athanasios A. Gavrilidis ◽  
Steluta Manolache ◽  
...  
Keyword(s):  
High Speed ◽  
Spatial Ecology ◽  
Local Environment ◽  
Quality Data ◽  
Aquatic Animal ◽  
Location Errors ◽  
Wildlife Tracking ◽  
Doppler Data ◽  
Proper Filter ◽  
And Behavior

ABSTRACTBackgroundAdvances in wildlife tracking technology have allowed researchers to understand the spatial ecology of many terrestrial and aquatic animal species. Argos Doppler is a technology that is widely used for wildlife tracking owing to the small size and low weight of the Argos transmitters. This allows them to be fitted to small-bodied species. The longer lifespan of the Argos units in comparison to units outfitted with miniaturized global positioning system (GPS) technology has also recommended their use. In practice, large Argos location errors often occur due to communication conditions such as transmitter settings, local environment, and the behavior of the tracked individual.MethodsConsidering the geographic specificity of errors and the lack of benchmark studies in Eastern Europe, the research objectives were: (1) to evaluate the accuracy of Argos Doppler technology under various environmental conditions in Romania, (2) to investigate the effectiveness of straightforward destructive filters for improving Argos Doppler data quality, and (3) to provide guidelines for processing Argos Doppler wildlife monitoring data. The errors associated with Argos locations in four geographic locations in Romania were assessed during static, low-speed and high-speed tests. The effectiveness of the Douglas Argos distance angle filter algorithm was then evaluated to ascertain its effect on the minimization of localization errors.ResultsArgos locations received in the tests had larger associated horizontal errors than those indicated by the operator of the Argos system, including under ideal reception conditions. Positional errors were similar to those obtained in other studies outside of Europe. The errors were anisotropic, with larger longitudinal errors for the vast majority of the data. Errors were mostly related to speed of the Argos transmitter at the time of reception, but other factors such as topographical conditions and orientation of antenna at the time of the transmission also contributed to receiving low-quality data. The Douglas-Argos filter successfully excluded the largest errors while retaining a large amount of data when the threshold was set to the local scale (2 km).DiscussionFilter selection requires knowledge about the movement patterns and behavior of the species of interest, and the parametrization of the selected filter typically requires a trial and error approach. Selecting the proper filter reduces the errors while retaining a large amount of data. However, the post-processed data typically includes large positional errors; thus, we recommend incorporating Argos error metrics such as error ellipse or use complex modeling approaches when working with filtered data.

scholarly journals A 1.55-to-32-Gb/s Four-Lane Transmitter with 3-Tap Feed Forward Equalizer and Shared PLL in 28-nm CMOS

Electronics ◽  
2021 ◽  
Vol 10 (16) ◽  
pp. 1873
Author(s):  
Chen Cai ◽  
Xuqiang Zheng ◽  
Yong Chen ◽  
Danyu Wu ◽  
Jian Luan ◽  
...  
Keyword(s):  
Data Transmission ◽  
High Speed ◽  
Data Rate ◽  
Quality Data ◽  
Cmos Process ◽  
Voltage Controlled Oscillator ◽  
Feed Forward ◽  
Fully Integrated ◽  
Output Driver ◽  
28 Nm

This paper presents a fully integrated physical layer (PHY) transmitter (TX) suiting for multiple industrial protocols and compatible with different protocol versions. Targeting a wide operating range, the LC-based phase-locked loop (PLL) with a dual voltage-controlled oscillator (VCO) was integrated to provide the low jitter clock. Each lane with a configurable serialization scheme was adapted to adjust the data rate flexibly. To achieve high-speed data transmission, several bandwidth-extended techniques were introduced, and an optimized output driver with a 3-tap feed-forward equalizer (FFE) was proposed to accomplish high-quality data transmission and equalization. The TX prototype was fabricated in a 28-nm CMOS process, and a single-lane TX only occupied an active area of 0.048 mm2. The shared PLL and clock distribution circuits occupied an area of 0.54 mm2. The proposed PLL can support a tuning range that covers 6.2 to 16 GHz. Each lane's data rate ranged from 1.55 to 32 Gb/s, and the energy efficiency is 1.89 pJ/bit/lane at a 32-Gb/s data rate and can tune an equalization up to 10 dB.

Visualization and Time-Resolved Particle Image Velocimetry Measurements of the Flow in the Tip Region of a Subsonic Compressor Rotor

2014 ◽  
Vol 137 (4) ◽  
Author(s):  
David Tan ◽  
Yuanchao Li ◽  
Ian Wilkes ◽  
Rinaldo L. Miorini ◽  
Joseph Katz
Keyword(s):  
Flow Rate ◽  
High Speed ◽  
Axial Compressor ◽  
Time Resolved ◽  
Tip Leakage ◽  
Compressor Rotor ◽  
Direct Measurements ◽  
Image Velocimetry ◽  
The One ◽  
And Behavior

A new optically index matched facility has been constructed to investigate tip flows in compressor-like settings. The blades of the one and a half stage compressor have the same geometry, but lower aspect ratio as the inlet guide vanes (IGVs) and the first stage of the low-speed axial compressor (LSAC) facility at NASA Glenn. With transparent blades and casings, the new setup enables unobstructed velocity measurements at any point within the tip region and is designed to facilitate direct measurements of effects of casing treatments on the flow structure. We start with a smooth endwall casing. High speed movies of cavitation and time-resolved PIV measurements have been used to characterize the location, trajectory, and behavior of the tip leakage vortex (TLV) for two flow rates, the lower one representing prestall conditions. Results of both methods show consistent trends. As the flow rate is reduced, TLV rollup occurs further upstream, and its initial orientation becomes more circumferential. At prestall conditions, the TLV is initially aligned slightly upstream of the rotor passage, and subsequently forced downstream. Within the passage, the TLV breaks up into a large number of vortex fragments, which occupy a broad area. Consequently, the cavitation in the TLV core disappears. With decreasing flow rate, this phenomenon becomes more abrupt, occurs further upstream, and the fragments occupy a larger area.

Wild Pig Spatial Ecology and Behavior

2019 ◽  
pp. 33-56
Author(s):  
Steven M. Gray ◽  
Gary J. Roloff ◽  
Robert A. Montgomery ◽  
James C. Beasley ◽  
Kim M. Pepin
Keyword(s):  
Spatial Ecology ◽  
And Behavior ◽  
Wild Pig

scholarly journals SUBSIDENCE EVALUATION OF HIGH-SPEED RAILWAY IN SHENYANG BASED ON TIME-SERIES INSAR

2018 ◽  
Vol IV-3 ◽  
pp. 273-276
Author(s):  
Yun Zhang ◽  
Lianhuan Wei ◽  
Jiayu Li ◽  
Shanjun Liu ◽  
Yachun Mao ◽  
...  
Keyword(s):  
Time Series ◽  
High Speed ◽  
Cross Validation ◽  
Surface Deformation ◽  
Local Environment ◽  
Local Area ◽  
Safe Operation ◽  
High Speed Rail ◽  
High Speed Railway ◽  
Under Construction

More and more high-speed railway are under construction in China. The slow settlement along high-speed railway tracks and newly-built stations would lead to inhomogeneous deformation of local area, and the accumulation may be a threat to the safe operation of high-speed rail system. In this paper, surface deformation of the newly-built high-speed railway station as well as the railway lines in Shenyang region will be retrieved by time series InSAR analysis using multi-orbit COSMO-SkyMed images. This paper focuses on the non-uniform subsidence caused by the changing of local environment along the railway. The accuracy of the settlement results can be verified by cross validation of the results obtained from two different orbits during the same period.

scholarly journals The proton and electron radiation belts at geosynchronous orbit: Statistics and behavior during high-speed stream-driven storms

2016 ◽  
Vol 121 (6) ◽  
pp. 5449-5488 ◽  
Author(s):  
Joseph E. Borovsky ◽  
Thomas E. Cayton ◽  
Michael H. Denton ◽  
Richard D. Belian ◽  
Roderick A. Christensen ◽  
...  
Keyword(s):  
High Speed ◽  
Radiation Belts ◽  
Geosynchronous Orbit ◽  
Electron Radiation ◽  
High Speed Stream ◽  
And Behavior

scholarly journals Who sees an hourglass? Assessing citizens’ perception of local economic inequality

2018 ◽  
Vol 5 (3) ◽  
pp. 205316801879397 ◽  
Author(s):  
Benjamin J. Newman ◽  
Sono Shah ◽  
Erinn Lauterbach
Keyword(s):  
Local Level ◽  
Economic Inequality ◽  
Local Environment ◽  
Lower Income ◽  
National Surveys ◽  
Steady Growth ◽  
Dependent Variables ◽  
Residential Context ◽  
And Behavior ◽  
Attitudes And Behavior

The scholarly literature is observing a slow but steady growth in research exploring the effects of subnational economic inequality on political attitudes and behavior. Germane to this work is the assumption that citizens are aware of the level of inequality in their local residential context. At present, however, the evidence in support of this assumption is mixed. This article attempts to offer the literature improved tests of citizens’ awareness of local inequality by addressing a key limitation in past work—the discordance between the geographic unit underlying measures of the independent and dependent variables. Analyzing two national surveys employing a measure of perceived inequality scaled to the local level, the results suggest that citizens are indeed aware of the level of income inequality in their local environment and that the link between objective and perceived local inequality is most pronounced among lower income citizens.

Forensic Uncertainty Quantification for Experiments on the Explosively Driven Motion of Particles

2018 ◽  
Vol 3 (4) ◽  
Author(s):  
Kyle Hughes ◽  
S. Balachandar ◽  
Nam H. Kim ◽  
Chanyoung Park ◽  
Raphael Haftka ◽  
...  
Keyword(s):  
Uncertainty Quantification ◽  
High Speed ◽  
Early Time ◽  
Operating Conditions ◽  
Quality Data ◽  
High Speed Photography ◽  
Particle Array ◽  
X Ray Imaging ◽  
Drag Models ◽  
Air Force Research Laboratory

Six explosive experiments were performed in October 2014 and February of 2015 at the Munitions Directorate of the Air Force Research Laboratory with the goal of providing validation-quality data for particle drag models in the extreme regime of detonation. Three repeated single particle experiments and three particle array experiments were conducted. The time-varying position of the particles was captured within the explosive products by X-ray imaging. The contact front and shock locations were captured by high-speed photography to provide information on the early time gas behavior. Since these experiments were performed in the past and could not be repeated, we faced an interesting challenge of quantifying and reducing uncertainty through a detailed investigation of the experimental setup and operating conditions. This paper presents the results from these unique experiments, which can serve as benchmark for future modeling, and also our effort to reduce uncertainty, which we dub forensic uncertainty quantification (FUQ).

The Incorporation and Behavior of Oxygen in AlGaAs Grown by Mombe Using Trimethylamine Alane

1990 ◽  
Vol 204 ◽  
Author(s):  
C. R. Abernathy ◽  
J. Song ◽  
W. S. Hobson ◽  
S. J. Pearton ◽  
F. Ren ◽  
...  
Keyword(s):  
High Speed ◽  
Room Temperature ◽  
Molecular Beam ◽  
Heterojunction Bipolar Transistor ◽  
Dopant Activation ◽  
Residual Oxygen ◽  
Oxygen Contamination ◽  
Metal Organic ◽  
And Behavior ◽  
Trimethylamine Alane

ABSTRACTTrimethylamine alane (TMAAl) has been demonstrated to be a superior Al precursor for growth of AIGaAs by metal-organic molecular beam (MOMBE). TMAA1 reduces both carbon and oxygen contamination relative to the standard Al source, triethylaluminum (TEA1). However, AlGaAs grown with TMAAl still shows a residual oxygen background of ∼2 × 1018 cm−3 when used with triethylgallium (TEGa) and either As4 or ASH3. This background is independent of Al mole fraction and is due primarily to alkoxides in the TEGa. AIGaAs grown with TMAAl and elemental Ga contains oxygen at levels commonly obtained in MBE, −2 × 1017 cm-3. While an oxygen level of −2 × 1018 cm-3 is not desirable, we have found that most of this impurity is electrically inactive as evidenced by room temperature photoluminescence and n-type dopant activation. In light of this, we have assessed the applicability of AlGaAs grown with TMAAl to the fabrication of high-speed GaAs/AIGaAs devices. The source is found to be suitable for structures like the heterojunction bipolar transistor.

Behavior of Damage in Selectively Implanted SiGe/Si

1993 ◽  
Vol 319 ◽  
Author(s):  
N. David Theodore ◽  
Gordon Tam ◽  
Jim Whitfield ◽  
Jim Christiansen ◽  
John Steele
Keyword(s):  
Heterojunction Bipolar Transistors ◽  
High Speed ◽  
Critical Thickness ◽  
Bipolar Transistors ◽  
Electrical Performance ◽  
Misfit Dislocations ◽  
Extended Defects ◽  
Dislocation Loops ◽  
And Behavior ◽  
Dislocation Sources

AbstractEpitaxial SiGe/Si layers are being extensively investigated for use in base regions of high-speed heterojunction bipolar-transistors (HBTs). Extended defects can be formed in SiGe/Si layers by ion-implantation. Defects, once formed in the layers, can negatively impact electrical performance and also future reliability of the HBTs. The present study investigates the interaction between selective-implant damage and strained SiGe/Si layers of sub-critical thickness. Implant-damage is observed to form dislocation-sources at the edges of implanted regions in SiGe/Si heterolayers. The dislocation sources produce glide dislocation loops. Segments of these loops glide down to SiGe/Si interfaces causing misfit dislocations to arise at interfaces in the heterolayers. Misfitdislocations are formed in directions parallel to and perpendicular to the <110> edge of the implanted region. Dislocations propagate out to a distance of ∼100-150 nm past the edge of the implant in the case of Si0.9Ge0.1/Si layers of sub-critical thickness. The origin and behavior of these defects is discussed.

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