2,873 research outputs found

    A Design Process Framework to Deal with Non-functional Requirements in Conceptual System Designs

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    To simultaneously satisfy the user needs and project-specific technical requirements, it is imperative that complex engineering systems are designed using contemporary, systematic approaches. This study presents a framework that combines Axiomatic Design and Fuzzy Analytic Hierarchy Process to ensure that designers can concurrently satisfy the functional and non-functional requirements along with the design constraints of conceptual system designs. A conceptual design case of an autonomous battery charging system for Unmanned Aerial Vehicles is presented as an illustrative case study. The results showed that the approach can aid decision-making processes by systematic evaluation and comparison of conceptual designs such that the selected solutions satisfy user needs whilst also realising both functional and non-functional requirements of the system

    The Wyoming Survey for H-alpha. I. Initial Results at z ~ 0.16 and 0.24

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    The Wyoming Survey for H-alpha, or WySH, is a large-area, ground-based, narrowband imaging survey for H-alpha-emitting galaxies over the latter half of the age of the Universe. The survey spans several square degrees in a set of fields of low Galactic cirrus emission. The observing program focuses on multiple dz~0.02 epochs from z~0.16 to z~0.81 down to a uniform (continuum+line) luminosity at each epoch of ~10^33 W uncorrected for extinction (3sigma for a 3" diameter aperture). First results are presented here for 98+208 galaxies observed over approximately 2 square degrees at redshifts z~0.16 and 0.24, including preliminary luminosity functions at these two epochs. These data clearly show an evolution with lookback time in the volume-averaged cosmic star formation rate. Integrals of Schechter fits to the extinction-corrected H-alpha luminosity functions indicate star formation rates per co-moving volume of 0.009 and 0.014 h_70 M_sun/yr/Mpc^3 at z~0.16 and 0.24, respectively. The formal uncertainties in the Schechter fits, based on this initial subset of the survey, correspond to uncertainties in the cosmic star formation rate density at the >~40% level; the tentative uncertainty due to cosmic variance is 25%, estimated from separately carrying out the analysis on data from the first two fields with substantial datasets.Comment: To appear in the Astronomical Journa

    Simultaneous real-time measurement of EEG/EMG and L-glutamate in mice: A biosensor study of neuronal activity during sleep

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    We report on electroencephalograph (EEG) and electromyograph (EMG) measurements concurrently with real-time changes in L-glutamate concentration. These data reveal a link between sleep state and extracellular neurotransmitter changes in a freely-moving (tethered) mouse. This study reveals, for the first time in mice, that the extracellular L-glutamate concentration in the pre-frontal cortex (PFC) increases during periods of extended wakefulness, decreases during extended sleep episodes and spikes during periods of REM sleep. Individual sleep epochs (10 s in duration) were scored as wake, slow-wave (SW) sleep or rapid eye movement (REM) sleep, and then correlated as a function of time with measured changes in L-glutamate concentrations. The observed L-glutamate levels show a statistically significant increase of 0.86 ± 0.26 μM (p < 0.05) over 37 wake episodes recorded from all mice (n = 6). Over the course of 49 measured sleep periods longer than 15 min, L-glutamate concentrations decline by a similar amount (0.88 ± 0.37 μM, p < 0.08). The analysis of 163 individual REM sleep episodes greater than one min in length across all mice (n = 6) demonstrates a significant rise in L-glutamate levels as compared to the 1 min preceding REM sleep onset (RM-ANOVA, DF = 20, F = 6.458, p < 0.001). The observed rapid changes in L-glutamate concentration during REM sleep last only between 1 and 3 min. The approach described can also be extended to other regions of the brain which are hypothesized to play a role in sleep. This study highlights the importance of obtaining simultaneous measurements of neurotransmitter levels in conjunction with sleep markers to help elucidate the underlying physiological and ultimately the genetic components of sleep

    Magnetic properties of Fe-doped CuAlO2 and role of impurities

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    The delafossite CuAlO2 is a rare p-type semiconductor with potential applications as a thermoelectric and as a dilute magnetic semiconductor when doped with transition metal ions. Reported here are results from our investigations of CuAl1-xFexO2 (x = 0, 0.01, 0.05, and 0.1) with a focus on the x-dependence of structural and magnetic properties, and role of impurities. The samples prepared by the solid-state reaction at 1,100°C were characterized by X-ray diffraction (XRD), energy dispersive (X-ray) spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The magnetic results show that the Curie constant (C), low temperature magnetization (M) and the lattice constants scale with x. High resolution M-H loop measurements at 300 K and 10 K show negligible coercivity HCat 10 K but HC ∼ 100 Oe at 300K. These results suggest the presence of minute quantities of hematite (α-Fe2O3) that are not detected in our XRD and XPS. The role of impurities on the published results in this system is discussed

    Efficient measurement of quantum gate error by interleaved randomized benchmarking

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    We describe a scalable experimental protocol for obtaining estimates of the error rate of individual quantum computational gates. This protocol, in which random Clifford gates are interleaved between a gate of interest, provides a bounded estimate of the average error of the gate under test so long as the average variation of the noise affecting the full set of Clifford gates is small. This technique takes into account both state preparation and measurement errors and is scalable in the number of qubits. We apply this protocol to a superconducting qubit system and find gate errors that compare favorably with the gate errors extracted via quantum process tomography.Comment: 5 pages, 2 figures, published versio

    The Panchromatic Hubble Andromeda Treasury: Triangulum Extended Region (PHATTER). III. The Mass Function of Young Star Clusters in M33

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    We measure the star cluster mass function for the Local Group galaxy M33. We use the catalog of stellar clusters selected from the Panchromatic Hubble Andromeda Treasury: Triangulum Extended Region (PHATTER) survey. We analyze 711 clusters in M33 with 7.0\rm 7.0 3.0 as determined from color-magnitude diagram fits to individual stars. The M33 cluster mass function is best described by a Schechter function with power law slope α=−2.06−0.13+0.14\alpha = -2.06^{+0.14}_{-0.13}, and truncation mass log(Mc/M⊙M_c/M_{\odot}) =4.24−0.13+0.16= 4.24^{+0.16}_{-0.13}. The data show strong evidence for a high-mass truncation, thus strongly favoring a Schechter function fit over a pure power law. M33's truncation mass is consistent with the previously identified linear trend between McM_c, and star formation rate surface density, \SigSFR. We also explore the effect that individual cluster mass uncertainties have on derived mass function parameters, and find evidence to suggest that large cluster mass uncertainties have the potential to bias the truncation mass of fitted mass functions on the one sigma level.Comment: 18 pages, 15 figures, 1 table, Accepted to ApJ (February 2, 2022
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