Absolute Magnitude Estimation Research Articles

K-band Absolute Magnitude Relations of Red Clump Stars Separated by Age

Red clump (RC) stars form a distinguishable clump on the color-magnitude diagram, making it a good distance indicator. Currently, the two main absolute magnitude estimation methods in the I-band (700–900 nm) conflict: one assumes a constant RC magnitude as supported by empirical data and one relates magnitude with other physical characteristics as supported by theoretical models. Studies attribute these discrepancies to population effects, such as dust, and recommend the K-band (2000–2400 nm) to minimize them. Past studies analyzed relations between the K-band magnitude, color, metallicity, and age, including those stratified by age at 2 Gyr. This study aims to investigate these different relations to clarify trends from past studies, discover new trends, and compare them to similar relations in the I-band. After analyzing cluster RC data from Gaia DR3, 2MASS, and Gaia-ESO DR5, K-band magnitude exhibits insignificant correlation in all relations (p>0.05) but has the greatest dependence and the least root mean square error (RMS) with metallicity in the old RC. Significant correlation was found between I-band magnitude and metallicity for all RC and young RC (p<0.05), especially the latter (R2 = 0.804). This consistency with theoretical trends suggests weaker I-band population effects than previously believed. Overall, these three relations yield more accurate predictions than the mean magnitude. Thus, studies cannot solely rely on the mean K-band or I-band magnitude to estimate distance, and magnitude relations stratified by age can potentially lead to more accurate RC distance estimations and a more accurately calibrated distance ladder.

Discomfort estimation for aircraft cabin noise using linear regression and modified psychoacoustic annoyance approaches.

Appropriate sound quality models for noise-induced discomfort are necessary for a better acoustic comfort design in the aircraft cabin. This study investigates the acoustic discomfort in two large passenger aeroplanes (i.e., planes A and B). We recorded the noise at 21 positions in each aircraft cabin and selected 42 stimuli ranging from 72 to 81 dB(A) during the cruising flights. Twenty-four participants rated the noise discomfort by the absolute magnitude estimation method. The discomfort values in the middle section of the aircraft cabin are 10% points higher than in the front or rear section. The discomfort magnitude was dominated by loudness and influenced by roughness and sharpness. A multiple linear (MA) discomfort model was established, accounting for the relationship between the discomfort and sound quality metrics (i.e., loudness, sharpness, and roughness). The MA model estimated noise discomfort better than the Zwicker and other (i.e., More and Di) psychoacoustic annoyance (PA) models. We modified the coefficients of independent variables in the formulations of Zwicker, Di, and More PA models, respectively, according to the present experimental results. The correlation coefficients between the estimated and measured values of the modified models were at least 20% points higher than the original ones.

Subjective evaluation of the acoustic annoyance in a large passenger aircraft cabin

People demand better acoustic comfort for higher travelling quality and security in aircraft. It is necessary to evaluate and predict the subjective annoyance caused by the noise in aircraft cabins. This study investigates the noise-induced annoyance in a large passenger aircraft. We recorded the noise at 21 positions in the aircraft cabin without passengers and selected 21 stimuli during the cruising. Each stimulus has a duration of 5 seconds and a sound pressure level in the range of 72-81dB(A). The psychoacoustic parameters such as loudness, sharpness, roughness and articulation index were also calculated. Twenty-four subjects evaluated the subjective annoyance of the stimuli by the absolute magnitude estimation method. Results showed the noise annoyance at the middle section of the cabin is significantly higher than that at the front or rear section. The principal component analysis and correlation analysis found that annoyance is mainly affected by loudness, sharpness and roughness and dominated by loudness. We proposed a multiple linear regression model between the subjective magnitudes of annoyance and the psychoacoustic parameters to evaluate and predict the noise annoyance in the aircraft cabin well.

Sound quality modelling of hairdryer noise

The demand for acoustic comfort in domestic appliances increases with the rapid growth of living quality requirements. As a common domestic appliance, the hairdryer produces unwanted noise that affects comfort during working. Manufacturers make great efforts to control the hairdryer noise, e.g., reduce the sound pressure level (SPL) by increasing blades number to make the frequency of noise energy above the hearing range. This study investigated the noise discomfort of a supersonic hairdryer (SHD) and three standard hairdryers (HD). We measured and recorded hairdryer noise at all operating conditions, and generated 120 test stimuli at SPLs ranging from 60 to 72 dB(A) in 3 dB steps based on 24 sound samples. Twenty-four subjects evaluated the noise discomfort of all stimuli using the absolute magnitude estimation (AME) method. The contribution of psychoacoustic metrics, i.e. loudness, sharpness, roughness, fluctuation strength, tonality (hearing model) and articulation index, to the noise discomfort was analysed by partial correlation analysis. Hairdryer noise discomfort was dominated by loudness and significantly influenced by tonality. The sound quality models were established for SHD and HD by multiple linear regression between the discomfort and two psychoacoustic metrics, i.e., loudness and tonality. The SHD performed better in sound quality for less discomfort and interference of communication than the HD, yet the adverse effects of the ultra-high frequencies on comfort and health need further consideration.

Effects of reverberation time and sound source composition on sense of place constructs

This study investigates the influence of reverberation time and sound source composition on the sense of place. The experiments were conducted in the private lecturer offices located in the Faculty of Architecture, Çankaya University. The sense of place of 15 participants was tested in the original offices of each participant and eight additional acoustic auralisations, in which reverberation times and sound source compositions were modified. The analysis of the results revealed that there is a direct influence of reverberation time and sound source composition on the sense of place. It was observed that longer reverberation times partially enhanced the sense of place. Additionally, the sound source composition influenced the relation towards the place, and certain sound signals diminished the sense of place in the private offices. Furthermore, this study used a psychophysical scaling method (Absolute Magnitude Estimation scale [AME]) which indicated its validity and importance in investigating the effect of physical stimuli on the sense of place. The AME revealed the sense of place by directing the influence towards the place construct indicators rather than investigating the general relation towards the place. It was concluded that reverberation time and sound source compositions could enhance and/or diminish sense of place; hence, RT and sound source compositions can affect interpretation of and behavior towards a given place.

Data-driven Spectroscopic Estimates of Absolute Magnitude, Distance, and Binarity: Method and Catalog of 16,002 O- and B-type Stars from LAMOST

Abstract We present a data-driven method to estimate absolute magnitudes for O- and B-type stars from the LAMOST spectra, which we combine with Gaia DR2 parallaxes to infer distance and binarity. The method applies a neural network model trained on stars with precise Gaia parallax to the spectra and predicts K s-band absolute magnitudes with a precision of 0.25 mag, which corresponds to a precision of 12% in spectroscopic distance. For distant stars (e.g., >5 kpc), the inclusion of constraints from spectroscopic significantly improves the distance estimates compared to inferences from Gaia parallax alone. Our method accommodates for emission-line stars by first identifying them via principal component analysis reconstructions and then treating them separately for the estimation. We also take into account unresolved binary/multiple stars, which we identify through deviations in the spectroscopic from the geometric inferred from Gaia parallax. This method of binary identification is particularly efficient for unresolved binaries with near equal-mass components and thus provides a useful supplementary way to identify unresolved binary or multiple-star systems. We present a catalog of spectroscopic , extinction, distance, flags for emission lines, and binary classification for 16,002 OB stars from LAMOST DR5. As an illustration, we investigate the of the enigmatic LB-1 system, which Liu et al. had argued consists of a B star and a massive stellar-mass black hole. Our results suggest that LB-1 is a binary system that contains two luminous stars with comparable brightness, and the result is further supported by parallax from the Gaia eDR3.

Subjective discomfort analysis of human body in semi-supine posture caused by vertical sinusoidal vibration

The vibration discomfort to the human body in semi-supine posture is currently evaluated as per ISO 2631-1, although it is recommended for sitting, standing and recumbent posture. The present study investigated the frequency-dependence of subjective responses of semi-supine humans to vertical vibration (0.5–1.5 m s−2 r.m.s.) across the frequency range 2.0–16.0 Hz. The subjects (14 males) judged the discomfort caused due to sinusoidal vibration using a modified absolute magnitude estimation method. The significant variation of rate of growth of discomfort across the frequency spectra caused the shape of equivalent comfort contour to vary with the vibration magnitude. The equivalent comfort contours illustrated significant discomfort between 8.0 and 10.0 Hz. Moreover, for frequencies above 10.0 Hz, substantial vibration acceleration was required to cause discomfort of the same intensity, implying that the frequency dependence of semi-supine posture is distinct from other postures. The frequency weighting obtained for semi-supine posture suggested that the discomfort estimation based on ISO 2631-1 was relatively accurate though conservative. Practitioner Summary: The discomfort caused by vertical vibration to the human in semi-supine posture was quite different from other postures. The present study provided the frequency-dependence of vibration discomfort for humans in semi-supine posture. Further, it investigated the suitability of frequency weightings defined in ISO 2631-1 for the acceleration measurements. Abbreviations: ISO: International Organization for Standardization; BS: British Standard; NASA: National Aeronautics and Space Administration; BMI: body mass index; AME: absolute magnitude estimation

Psychophysical principles of discrete event-driven vibrotactile feedback for prostheses

Purpose/aim of the study: We aimed to establish psychophysical principles for non-invasive vibrotactile feedback signalling discrete transition events (e.g., extension to flexion) during use of prostheses, especially for the upper limbs.Materials and methods: Two vibrotactile actuators were used on both upper arms of 10 able-bodied human participants. Absolute thresholds, psychometric functions, and magnitude estimates were measured to equalize the sensation magnitudes for the tested vibrotactile frequencies and skin sites. Then, same-different and pattern recognition tasks were run to evaluate, respectfully, the discrimination and closed-set identification of stimuli with varying parameters (2 frequencies, 2 magnitudes, 2 sites). Finally, parameters of the left/right stimuli were mapped to hypothetical prosthesis events representing object/force and movement type. The stimuli were applied sequentially in accordance with the discrete event-driven feedback paradigm.Results: Reliable psychophysical models could be established for individual participants as verified by repetitive threshold measurements and relative adjustment of stimulus levels based on sensation magnitudes. Discrimination accuracy was higher for magnitude versus frequency comparisons; and magnitude discrimination accuracy was correlated with magnitude estimate differences. Pattern recognition recall/precision rates decreased from ∼0.7 to ∼0.5 for sequential delivery of two stimulus patterns to one arm versus to two arms. Using the patterns as two and three consecutive prosthesis events yielded statistically similar performance rates not correlated with magnitude estimate differences.Conclusions: By careful calibration of stimuli based on psychophysical principles, discrete event-driven vibrotactile feedback can be used to signal manipulated object and movement information with moderate identification rates as shown by confusion matrices.

An empirical category-ratio scale for evaluating the subjective intensity of noise based on the comparison of estimated magnitudes and categories

In psychophysical studies, the methods of magnitude estimation (ME) and rating scale (RS) are often employed to obtain the subjective intensity of noise. Research interest has usually focused on obtaining precise growth functions to express the relation between subjective and objective magnitudes of stimuli in the ME method, or utilising proper categories for a series of stimuli in the RS method. There have been few studies concerned with the validity of the two direct scaling methods in measuring the subjective intensity of noise. This paper investigated the subjective discomfort caused by noise in the methods of relative magnitude estimation (RME), absolute magnitude estimation (AME), and RS. Forty-two participants were divided into three groups, and each group rated the discomfort caused by 22 noise stimuli at sound pressure levels from 49 to 91 dBA using RME, AME or RS method, respectively. Results indicated that the RS method yields interval scales and the ME method yields logarithmic interval scales for the discomfort of noise, so the sensory continua of noise discomfort could be described in linear relation or power function, depending on the evaluating methods. Based on the empirical data, a category-ratio scale was developed for evaluating the noise discomfort by combining the scales of AME and the scales and verbal descriptors of RS. Equations were also proposed tentatively for noise discomfort to predict the categories from the estimated magnitudes.

CO Detected in CI Tau b: Hot Start Implied by Planet Mass and MK

Abstract We acquired high-resolution infrared spectra of CI Tau, the host star of one of the few young planet candidates amenable to direct spectroscopic detection. We confirm the planet’s existence with a direct detection of CO in the planet’s atmosphere. We also calculate a mass of 11.6 M J based on the amplitude of its radial velocity variations. We estimate its flux contrast with its host star to get an absolute magnitude estimate for the planet of 8.17 in the K-band. This magnitude implies the planet formed via a “hot start” formation mechanism. This makes CI Tau b the youngest confirmed exoplanet as well as the first exoplanet around a T Tauri star with a directly determined, model-independent dynamical mass.

Identification of perceived sound discomfort contributed from partially correlated vibration and noise sources in vehicles

The interior noise sources are often complex in vehicles, including not only structure-borne and air-borne noise sources but also vibration sources. These sources may be partially correlated and cannot be calculated using traditional methods, e.g., transfer path analysis and operational path analysis. On the other hand, it is necessary to study the sound quality of the vehicle interior noise to improve the comfort of drivers and passengers in vehicles. An operational partial singular value decomposing method together with sound quality analyses was employed in this study to determine the influence of various partially correlated sources with the perceived discomfort of the subject. The vibration and noise in vehicles were measured in a car when it was running on asphalt, concrete, gravel and bumpy roads. Thirty subjects used the absolute magnitude estimation method to rate the discomfort produced by noise stimuli. A discomfort model was proposed based on the relations between subjective magnitudes and the objective parameters of noise (i.e., the SPL, loudness, roughness, sharpness, and articulation index). The contributions of various vibration and noise sources to the vehicle discomfort were predicted well by the operational partial singular value decomposing method based on the discomfort model.

Subjective discomfort caused by vertical whole-body vibration in the frequency range 2–100 Hz

Current standards assume the same frequency weightings for discomfort at all magnitudes of vibration, whereas biodynamic and psychological studies show that the frequency-dependence of objective and subjective responses of the human body depends on the magnitude of vibration. This study investigated the discomfort of seated human body caused by vertical whole-body vibration over the frequency range 2–100 Hz at relatively high magnitudes from 1.0 to 2.5 ms−2 r.m.s. Twenty-eight subjects (15 males and 13 females) judged the discomfort using the absolute magnitude estimation method. The rate of growth of discomfort with increasing vibration magnitude was highly dependent on the frequency, so the shapes of the equivalent comfort contours depended on the magnitude of vibration and no single frequency weighting would be appropriate for all magnitudes. The equivalent comfort contours indicated that the standards and previous relevant studies underestimated the vibration discomfort at frequencies greater than about 30 Hz.Practitioner Summary: The discomfort caused by vertical vibration at relatively high frequencies can be severe, particularly at relatively great magnitudes in transport. This study provides the frequency-dependence of vibration discomfort at 2–100 Hz, and shows how the frequency weightings in the current standards can be improved at relatively high frequencies.

Expert judgments for performance shaping Factors’ multiplier design in human reliability analysis

Human reliability analysis (HRA) still heavily relies on expert judgments to generate reliability data. There exists a widely recognized need to validate and justify the reliability data obtained from expert judgments. For demonstrating such effort, we provide a template of how we base expert elicitations and empirical studies to derive the multipliers of performance shaping factors (PSFs). We applied two expert judgment techniques—absolute probability judgment (APJ) and ratio magnitude estimation (RME)—to update the PSF multiplier design in Standardized Plant Analysis of Risk-Human Reliability Analysis (SPAR-H). Licensed operators (N = 17) from a nuclear power plant were recruited. It is found that APJ and RME have acceptable inter-rater reliability and convergent validity between them. The multipliers estimated by APJ and RME were compared with those from empirical studies in the human performance literature. Certain consistencies between these heterogeneous data sources were found. Combining these heterogeneous data, we suggested the multiplier design of PSFs for SPAR-H. We also bridged the relationship between every PSF and its psychological mechanism to trigger human errors. Our work might suggest the appropriateness of expert elicitations in generating useful data for HRA, and strengthen the empirical and psychological foundations of PSF-based HRA methods.

Subjective discomfort model of the micro commercial vehicle vibration over different road conditions

Vibration is a main environmental stress in vehicles. The discomfort caused by vibration may differ in different vehicles and road conditions. This laboratory study investigated the discomfort caused by the vibration of 3 models of micro commercial vehicles running in 4 types of road conditions (i.e., the asphalt, concrete, gravel and bump road). Thirty participants judged the subjective discomfort caused by 72 whole-body vibration stimuli with the Wk weighted root-mean-square (r.m.s.) accelerations ranging from 0.531 to 2.991 ms−2 using the absolute magnitude estimation method. Results showed that at the same acceleration, especially at relatively great accelerations (>1.5 ms−2), vibration containing more high-frequency components (>20 Hz) caused greater discomfort than those containing less high-frequency components. Different discomfort models of vibration and different equivalent comfort contours between noise and vibration in various vehicles and road conditions were determined. The discomfort models would predict the discomfort from the r.m.s. accelerations of whole-body vibration (together with vibration in hand and foot) accurately, and the equivalent comfort contours would help to make a targeted improvement of noise and vibration.

Electrically-evoked auditory steady-state responses as neural correlates of loudness growth in cochlear implant users

Loudness growth functions characterize how the loudness percept changes with current level between the threshold and most comfortable loudness level in cochlear implant users. Even though loudness growth functions are highly listener-dependent, currently default settings are used in clinical devices. This study investigated whether electrically-evoked auditory steady-state response amplitude growth functions correspond to behaviorally measured loudness growth functions. Seven cochlear implant listeners participated in two behavioral loudness growth tasks and an EEG recording session. The 40-Hz sinusoidally amplitude-modulated pulse trains were presented to CI channels stimulating at a more apical and basal region of the cochlea, and were presented at different current levels encompassing the listeners' dynamic ranges. Behaviorally, loudness growth was measured using an Absolute Magnitude Estimation and a Graphic Rating Scale with loudness categories. A good correspondence was found between the response amplitude functions and the behavioral loudness growth functions. The results are encouraging for future advances in individual, more automatic, and objective fitting of cochlear implants.

The discomfort model of the micro commercial vehicles interior noise based on the sound quality analyses

The micro commercial vehicles are very popular in the developing areas of China for its capability of loading both cargoes and people. With the demands of customers for improving the comfort of vehicles, it is necessary to develop a discomfort model of noise for the micro commercial vehicles based on the acoustical characteristics of the interior noise, which are different from other passenger cars when they are running in various road conditions. This study investigated the discomfort produced by noise of 3 models of micro commercial vehicles when they are running in 4 types of road conditions, i.e., the asphalt, concrete, gravel and bump road. Seventy-four noise stimuli with the sound pressure levels (SPLs) ranging from 52 to 70 dB(A) were regenerated based on the recorded noise samples for the subjective evaluation experiment. Thirty subjects judged the subjective discomfort of the noise stimuli using the absolute magnitude estimation (AME) method. The relation between the subjective magnitudes of discomfort and the acoustical parameters (i.e., the loudness, sharpness, roughness and articulation index) was analyzed. A tentative equation was obtained by multiple linear regression analysis to predict the discomfort caused by noise of the micro commercial vehicles. The partial correlation analysis was applied to determine the contribution of each psycho-acoustical parameter on discomfort. The results showed that the loudness and sharpness were the influential factors of the discomfort. The subjective magnitudes of discomfort were also transformed into the ratings scales, which were usually employed by car companies.

Estimating stellar atmospheric parameters, absolute magnitudes and elemental abundances from the LAMOST spectra with Kernel-based principal component analysis

Accurate determination of stellar atmospheric parameters and elemental abundances is crucial for Galactic archeology via large-scale spectroscopic surveys. In this paper, we estimate stellar atmospheric parameters -- effective temperature T_{\rm eff}, surface gravity log g and metallicity [Fe/H], absolute magnitudes M_V and M_{Ks}, {\alpha}-element to metal (and iron) abundance ratio [{\alpha}/M] (and [{\alpha}/Fe]), as well as carbon and nitrogen abundances [C/H] and [N/H] from the LAMOST spectra with amultivariate regressionmethod based on kernel-based principal component analysis, using stars in common with other surveys (Hipparcos, Kepler, APOGEE) as training data sets. Both internal and external examinations indicate that given a spectral signal-to-noise ratio (SNR) better than 50, our method is capable of delivering stellar parameters with a precision of ~100K for Teff, ~0.1 dex for log g, 0.3 -- 0.4mag for M_V and M_{Ks}, 0.1 dex for [Fe/H], [C/H] and [N/H], and better than 0.05 dex for [{\alpha}/M] ([{\alpha}/Fe]). The results are satisfactory even for a spectral SNR of 20. The work presents first determinations of [C/H] and [N/H] abundances from a vast data set of LAMOST, and, to our knowledge, the first reported implementation of absolute magnitude estimation directly based on the observed spectra. The derived stellar parameters for millions of stars from the LAMOST surveys will be publicly available in the form of value-added catalogues.

Auditory steady-state responses as neural correlates of loudness growth

The aim of this study was to find an objective estimate of individual, complete loudness growth functions based on auditory steady-state responses. Both normal-hearing and hearing-impaired listeners were involved in two behavioral loudness growth tasks and one EEG recording session. Behavioral loudness growth was measured with Absolute Magnitude Estimation and a Graphic Rating Scale with loudness categories. Stimuli were sinusoidally amplitude-modulated sinusoids with carrier frequencies of either 500 Hz or 2000 Hz, a modulation frequency of 40 Hz, a duration of 1 s, and presented at intensities encompassing the participants’ dynamic ranges. Auditory steady-state responses were evoked by the same stimuli using durations of at least 5 min. Results showed that there was a good correspondence between the relative growth of the auditory steady-state response amplitudes and the behavioral loudness growth responses for each participant of both groups of listeners. This demonstrates the potential for a more individual, objective, and automatic fitting of hearing aids in future clinical practice.

A New Tool to Assess the Perception of Stretching Intensity.

This study aimed to develop a valid and reliable scale to assess the perception of stretching intensity below and above the maximal range of motion. Experiments were conducted through a passive leg extension angle-torque assessment to healthy population (n = 90). In the study's first phase, the visual, numerical, and description of the stretching intensity scale (SIS) components were developed. The visual analog scale (VAS) score, absolute magnitude estimation (AME) score, and verbal stretching intensity symptom descriptors were assessed for different stretching intensities. In the second phase, the SIS was tested for validity, reliability, scale production, and estimation properties as well as responsiveness to stretching. In the first phase, a high correlation was found between SIS score and range of motion (ROM), as well as SIS and torque in both submaximal (intraclass correlation coefficient [ICC] = 0.89-0.99, r = 0.88-0.99) and supramaximal (ICC = 0.75-0.86, r = 0.68-0.88) stretching intensities. The AME and VAS scores fitted well in an exponential model for submaximal stretching intensities (y = 14.829e, ICC = 0.97 [0.83-0.99], r = 0.98), and in a linear model for supramaximal stretching intensities (y = 0.7667x - 25.751, ICC = 0.97 [0.89-0.99], r = 0.9594). For the second phase, a high correlation was found between SIS score and ROM (r = 0.70-0.76, ICC = 0.76-0.85), as well as SIS and torque (r = 0.62-0.88, ICC = 0.57-0.85). The interday reliability was high to produce (r = 0.70, ICC = 0.70 [0.50-0.83]) or estimate (r = 0.89, ICC = 0.89 [0.82-0.93]) stretching intensities. The acute stretching effects on ROM and passive torque were detectable using the SIS. It is expected a high application in assessing the stretch intensity using the SIS in future studies and practical interventions.

Some factors influencing loudness asymmetries between rising and falling-intensity stimuli

Previous research demonstrated that the loudness asymmetry between 1-kHz rising and falling-intensity tones is a robust phenomenon, whose origins still remain unclear. In the present study, this phenomenon was further examined as a function of two stimuli characteristics: the spectral content and the intensity-region. In a first experiment, the global loudness of rising and falling-intensity sounds with various spectral contents (pure tones from 250 Hz to 8 kHz and broadband noises) presented in different intensity-regions (from [50–65 dB SPL] to [70–85 dB SPL]) was assessed in an absolute magnitude estimation task. Significant asymmetries were found for tones at all frequencies, but not for broadband noises. In addition, a significant interaction between the stimulus direction and the intensity-region was observed for both tones and noises. This interaction was further examined in a second experiment using an adaptive loudness-matching procedure. Although greater asymmetries were again observed for tones...