4,741 research outputs found
Provisional specification for satellite time in a geomagnetic environment
Satellites in geosynchronous orbit were experiencing operational anomalies. These anomalies are believed to be due to the environment charging the spacecraft surfaces to a point where discharges occur. In designing future satellites for long term operation at geosynchronous altitude, it is important that designers have a specification that will give the total time per year, the particle flux density and particle energies that their satellites can be expected to encounter in these substorm environmental conditions. The limited data currently available on the environmental conditions are used to generate the provisional specification given in this report
Very high voltage latching relay
Relay consists of high voltage reed switch actuated by rotating permanent magnet mounted on stepper motor shaft, with actuation assembly isolated from high voltage circuit. Unit can be modified for use as double pole or double pole double throw latching relay and can be used in either air or vacuum
Beginning Band: First Steps Instructing Students With Wind Instruments
One of the most important moments in beginning band is when a student first learns how to assemble and hold the instrument. As a band director, it is vital to be precise in explaining each element of this process. If steps are skipped over in this process, bad habits can form quickly and will cause more issues for the director. Instrument assembly and holding the instrument are covered in detail to help young band directors know how to explain this process. Additionally, this will help to find the bad habits quickly so problems do not snowball over time. It is always important to be proactive in the first steps. The next chapter covers core concepts such as learning the note names, rhythm, and practice habits in detail. The purpose is to help young band directors know where to start once the beginning band book is opened and ready to start the year
Line shifts in the first overtone of DF broadened by HF
Line spectra shifts in HF and in first overtone band of DF induced by HF pressure
Provisional specification for satellite time in a geomagnetic substorm environment
Satellites in geosynchronous orbit have been experiencing operational anomalies. These anomalies are believed to be due to the environment charging the spacecraft surfaces to a point where discharges occur. In designing future satellites for long term operation at geosynchronous altitude, it is important that designers have a specification that will give the total time per year, the particle flux density, and particle energies that their satellites can be expected to encounter in these substorm environmental conditions. The limited data currently available on the environmental conditions was used to generate the provisional specification given
Water Vapour Effects in Mass Measurement
Water vapour inside the mass comparator enclosure is a critical parameter. In
fact, fluctuations of this parameter during mass weighing can lead to errors in
the determination of an unknown mass. To control that, a proposal method is
given and tested. Preliminary results of our observation of water vapour
sorption and desorption processes from walls and mass standard are reported
Signal quality measures for unsupervised blood pressure measurement
Accurate systolic and diastolic pressure estimation, using automated blood pressure measurement, is difficult to achieve when the transduced signals are contaminated with noise or interference, such as movement artifact. This study presents an algorithm for automated signal quality assessment in blood pressure measurement by determining the feasibility of accurately detecting systolic and diastolic pressures when corrupted with various levels of movement artifact. The performance of the proposed algorithm is compared to a manually annotated reference scoring (RS). Based on visual representations and audible playback of Korotkoff sounds, the creation of the RS involved two experts identifying sections of the recorded sounds and annotating sections of noise contamination. The experts determined the systolic and diastolic pressure in 100 recorded Korotkoff sound recordings, using a simultaneous electrocardiograph as a reference signal. The recorded Korotkoff sounds were acquired from 25 healthy subjects (16 men and 9 women) with a total of four measurements per subject. Two of these measurements contained purposely induced noise artifact caused by subject movement. Morphological changes in the cuff pressure signal and the width of the Korotkoff pulse were extracted features which were believed to be correlated with the noise presence in the recorded Korotkoff sounds. Verification of reliable Korotkoff pulses was also performed using extracted features from the oscillometric waveform as recorded from the inflatable cuff. The time between an identified noise section and a verified Korotkoff pulse was the key feature used to determine the validity of possible systolic and diastolic pressures in noise contaminated Korotkoff sounds. The performance of the algorithm was assessed based on the ability to: verify if a signal was contaminated with any noise; the accuracy, sensitivity and specificity of this noise classification, and the systolic and diastolic pressure differences between the result obtained from the algorithm and the RS. 90% of the actual noise contaminated signals were correctly identified, and a sample-wise accuracy, sensitivity and specificity of 97.0%, 80.61% and 98.16%, respectively, were obtained from 100 pooled signals. The mean systolic and diastolic differences were 0.37 ± 3.31 and 3.10 ± 5.46 mmHg, respectively, when the artifact detection algorithm was utilized, with the algorithm correctly determined if the signal was clean enough to attempt an estimation of systolic or diastolic pressures in 93% of blood pressure measurements
Manufacturing Multiple View Constraints
In this paper we present an algorithm for the generation of the multiple view constraints for arbitrary configurations of cameras and image features correspondences. Multiple view constraints are an important commodity in computer vision since they facilitate in determining camera locations using only the correspondences between common features observed in sets of uncalibrated images. We show that by a series of counting arguments and a systematic application of the principles of antisymmetric algebra it is possible to generate arbitrary multiple view constraints in a completely automated fashion. The algorithm has already been utilized to discover new sets of multiple view constraints for surfaces
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