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Showing 1 to 20 of 80 for “"RFI"”.
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Time domain classification of transient RFI
… been afflicted by radio frequency interference (RFI). RFI continues to present a problem despite increasingly sophisticated countermeasures developed over the decades. Due to technological improvements, radio telescopes have become more sensitive (for example, MeerKAT’s L-band receiver). Existing …
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RFI monitoring for the MeerKAT Radio Telescope
… a low level of Radio Frequency Interference (RFI). It is important to maintain a low level of RFI to ensure that MeerKAT has an unobstructed view of the universe across its bandwidth. The only way to effectively manage the environment is with a record of RFI around the telescope. The RFI …
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Time Blanking for GBT Data with RADAR RFI
… are complicated by radio frequency interference (RFI) from strong man-made transmissions such as the ARSR-3 Air Surveillance Radar. In this thesis, we characterize some data files recorded at the National Radio Astronomy Observatory (NRAO) at Green Bank, West Virginia, USA, where this RADAR system …
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L-band RFI measurement system simulation and investigation
… must conform to a document called the "RFI Measurement Protocol for Candidates SKA Sites", the SKA Memo 37. The RFI protocol divides measurements into two parts, Mode 1 and Mode 2. Mode 1 is defined for the observation of strong RFI and is relevant for SKA receiver linearity analysis. …
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A study of the SA SKA RFI measurement systems
… the findings of a study of the functionality of RFI Measurement System 2 that was conducted by the author. An in depth study of MEMO 37 (RFI Measurement Protocol) was employed first. After which, an exhaustive audit of all the equipment used and a thorough analysis of the method of data …
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Genetic programming applied to RFI mitigation in radio astronomy
… as signal or radio frequency interference (RFI) generated by instruments and machinery which makes challenging astronomers' ability to discern the desired targets. The training data was derived from the output of an observation run of the KAT-7 radio telescope array built by the South …
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Design and Implementation of an RFI Direction Finding System for SKA Applications
… environment. Any radio frequency interference (RFI) will interfere with the ability of the telescope to collect data. With the proliferation of electrical and electronic devices, RFI management is one of the major challenges facing radio astronomy reserves. This thesis details the design, …
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A scalable database model of RFI data for the MeerKAT/SKA radio telescope
In radio astronomy, radio frequency interference (RFI) refers to any signal captured by a radio telescope that did not originate from the observed target in the sky. RFI from terrestrial and other sources is a recognized problem that contaminates the desired signal and must be tracked and …
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Construction of FASR subsystem testbed and application for solar burst trajectories and RFI study
… (e.g., different bit-sampling, windowing, and RFI excision methods) to test the effects of different designs. As a prototype of the FASR system, FST provides the opportunity to study the design, calibration and interference-avoidance requirements of FASR. In addition, FST provides, for the …
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Radio frequency interference (RFI) modeling of complex modules in mobile devices and system-level modeling for transient ESD simulation
… modeling of radio-frequency-interference (RFI) and electro-static-discharge (ESD) problems happened in mobile devices.</p> <p>In the first paper, an averaging technique is developed, for phase resolved scanning over random fields generated by multiple uncorrelated stochastic sources. This …
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Residual feed intake, breed of sire and dam, and individual sire affect performance and carcass characteristics and rates of back fat and intramuscular fat of feedlot steers
… medium (M), and low (L) residual feed intake (RFI) groups. Steers in the H RFI group ate 1 kg more of DMI (P< 0.05) per day than steers in the L and M RFI group. Steers in the L RFI group had the highest feed efficiency by gaining 15% and 22% more per kg of feed than steers in the M and H RFI …
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The MeerKAT Radio Frequency Interference Environment
… electronics. These Radio Frequency Interference (RFI) are increasingly threatening radio observatories due to our increasingly technological world. To detect and mitigate RFI, observatories need to understand their RFI environment, what contributes to it and how it is changing. While there are few …
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The relationship between mitochondria and residual feed intake in feedlot cattle
Residual feed intake (RFI) is a measure of feed efficiency that is not related to an animal's growth rate or body size. Little is known about the factors that affect RFI because, until recently, the measurement of RFI in large numbers of animals was not possible. Recently, researchers have shown a …
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Radio Frequency Interference: Simulations for Radio Interferometry Arrays
Radio Frequency Interference (RFI) is a massive problem for radio observatories around the world. Due to the growth of telecommunications and air travel RFI is increasing exactly when the world's radio telescopes are increasing significantly in sensitivity, making RFI one of the most pressing …
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Electrophoretic Mobilities of Topoisomers of ΦX174 DNA
… containing a single base mismatch (relaxed RFI molecules) were constructed <em>in vitro</em>, purified by sedimentation, and analyzed by zone electrophoresis on 1.4% agarose gels. In order to verify that the band of denaturation-resistant heteroduplex was indeed relaxed RFI, we compared it …
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The Relationship between Residual Feed Intake, Dry Matter Intake, and Reproductive Performance in Holstein Dairy Cows
… this study is measured in residual feed intake (RFI), which is calculated as the difference between DMI and expected DMI based on production and growth measures. However, the RFI model does not capture the energy stores required for reproduction; therefore, selection for RFI may lead to reduced …
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RESIDUAL FEED INTAKE AND THE RELATIONSHIP WITH PERFORMANCE, TEMPERAMENT AND CARCASS TRAITS IN GROWING AND FINISHING STEERS
… 70 d during both phases. Residual feed intake (RFI) is the difference between actual DMI and DMI predicted from linear regression of DMI on mid-test metabolic body weight. Ultrasound carcass measurements were measured on day 0 and 70 of the growing phase. Steers were harvested after finishing …
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Factors influencing cow performance and intake
… how weaning system, residual feed intake (RFI), and residual average daily gain (RADG) affect cow performance and intake. In Study 1, a two-year study was conducted using Angus and Simmental X Angus heifers (n=114) to evaluate how weaning system (early weaning (EW) vs. normal weaning (NW)) …
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Machine Learning for Radio Frequency Interference Flagging
The field of radio frequency interference (RFI) flagging involves the identification of corrupted data within radio astronomy measurements. This work explores the application of supervised machine learning algorithms for RFI flagging, trained on real measurement data and simulated data with …
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Efficient estimation and mitigation for radio-frequency interference
… possibly introduce radio frequency interference (RFI) issues. In this dissertation, a transfer function based calculation method is proposed to estimate radio frequency interference (RFI) problems. The derived equations can clearly decompose the RFI problem into two parts: the noise source and the …
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