Receiver Positions Research Articles

Three diverse motives for information sharing

Knowledge is distributed over many individuals. Thus, humans are tasked with informing one another for the betterment of all. But as information can alter people’s action, affect and cognition in both positive and negative ways, deciding whether to share information can be a particularly difficult problem. Here, we examine how people integrate potentially conflicting consequences of knowledge, to decide whether to inform others. We show that participants (Exp1: N = 114, Pre-registered replication: N = 102) use their own information-seeking preferences to solve complex information-sharing decisions. In particular, when deciding whether to inform others, participants consider the usefulness of information in directing action, its valence and the receiver’s uncertainty level, and integrate these assessments into a calculation of the value of information that explains information sharing decisions. A cluster analysis revealed that participants were clustered into groups based on the different weights they assign to these three factors. Within individuals, the relative influence of each of these factors was stable across information-seeking and information-sharing decisions. These results suggest that people put themselves in a receiver position to determine whether to inform others and can help predict when people will share information.

A Python-Based Indoor Channel Model with Multi-Wavelength Propagation for Color Shift Keying

Color shift keying is a modulation scheme for visible light communication that uses fixtures with three or more narrow-spectral light-emitting diodes to transmit data while fulfilling the primary function of illumination. When this modulation is used indoors, the reflectivity of the walls strongly affects the inter-channel interference and illumination quality. In this paper, we present an indoor channel model that takes into account multi-wavelength propagation. This model is available as an open-source Python package. The model calculates the inter-channel interference, illuminance, correlated color temperature, and color rendering index at the receiver position. The Python package includes a module for estimating the symbol error rate. To validate the model, we computed the received power at each color photodetector for four different indoor scenarios. The model demonstrated a color rendering index of less than 15 when using IEEE-based color shift keying and non-uniform illumination on a horizontal plane. The simulation determined the required luminous flux to achieve a symbol error rate of less than 10−5 when the photodetector is at the center of the indoor space and vertically below the light source. To maintain a symbol error rate less than 10−5, the luminous flux increases when the photodetector is displaced in a diagonal direction from the center of the plane.

IRS aided visible light positioning with a single LED transmitter

We propose a visible light positioning (VLP) system with a single light emitting diode (LED) transmitter and an intelligent reflecting surface (IRS) for estimating the position of a receiver equipped with a single photo-detector. By performing a number of transmissions from the LED transmitter and optimizing the orientation vectors of the IRS elements for each transmission, position information is extracted by the receiver based on power measurements of the signals reflecting from the IRS. The theoretical limit and the maximum likelihood (ML) estimator are presented for the proposed setting. In addition, an algorithm, named IRS focusing, is proposed for determining the orientations of the IRS elements during the localization process. The effectiveness of the proposed localization approach is demonstrated through simulations. Furthermore, extensions are provided to apply the proposed approach in the presence of partial prior information about the receiver position and when the IRS is located at the LED transmitter.

Validation measurement of vehicle pass-by models for dynamic urban environments

Simulation and auralization of urban traffic noise can help city planners and residents to improve existing urban areas or plan new attractive living spaces while enabling discussions about shared auditory experiences, regardless of expertise. Evaluating street noise in the context of urban areas requires careful consideration of their urban surroundings, such as landscapes, buildings, and other structures. Obtaining measurements to validate simulations may be difficult given the variety and complexity of sounds within an urban setting. Recreating the real urban scenario on a test track, e.g., including building facades and exact source and receiver positions, helps validate simulations but also poses challenges due to varying road surfaces, weather conditions, and disturbances such as industrial or fly-over sounds. This research represents a method of bringing a measurement set-up consisting of source (e.g., vehicle), receiver (e.g., pedestrian), and surfaces (e.g., walls) to the more controlled environment of a hemi-anechoic chamber. The method is intended for the validation of previous vehicle pass-by measurements by utilizing sine sweeps with walls parked at varying distances. These environments aim to deliver more insight into the relevance of diffracted sound for configuration of urban sound simulation models.

Receiver Position Detection System of Wireless Electric Vehicle Charger Based on Novel Active Beacon Structure

Receiver Position Detection System of Wireless Electric Vehicle Charger Based on Novel Active Beacon Structure

Design optimization of a new cavity receiver for a parabolic trough solar collector

The most important parameter affecting the optical efficiency, the upper limit for an overall efficiency of parabolic trough solar collector (PTC), is the net absorbed heat rate by receiver on which solar beam radiation is concentrated. The objective of this study is to propose and optimize a new cavity receiver used in PTC for increasing optical efficiency. Three different geometries (triangle, rectangle and polygon), aperture widths, heights and positions of cavity receiver are taken as optimization parameters. A design of experiments (DoE) approach is used to evaluate the effects of these parameters on the absorbed radiation heat rate by receiver at the same time. SolTrace is used to investigate the effects of these parameters by optical analysis. The results indicate that the optimum cavity geometry is polygonal, and the cavity depth and aperture both are equal to 0.05 m. Moreover, it is found that the most effective parameter is the position of the cavity receiver, and the optimum position is at the focal line of the parabolic concentrator. The highest absorbed radiation rate by the cavity receiver and the optical efficiency of the PTC are equal to 3241.99 W and 81.05 % respectively for the optimum cavity receiver design.

Employing a two stage process with resampling, decision rules, and fine acquisition to optimize the acquisition stage of GNSS receiver performance

The optimal design of Global Navigation Satellite System (GNSS) software receivers should enable the accurate estimation of the receiver's position, velocity, and time under various environmental conditions. The software receivers consist of three sections: acquisition, tracking, and navigation. This paper specifically centers on the acquisition sections of the Global Positioning System (GPS), Global Navigation Satellite System (GLONASS), BeiDou, and Galileo satellite navigation systems. The acquisition stage necessitates the prompt and precise transmission of the satellite list within the receiver's view, along with Doppler frequency estimation and phase code offset, to facilitate a seamless transition to the tracking stage with the utmost speed and accuracy. Conventional acquisition demonstrates commendable speed, but lacks accuracy, especially in environments with a low Carrier-to-Noise Ratio (CNR). Contrastingly, precise acquisition methods will impede the speed of the acquisition stage. In this paper, a novel acquisition method is proposed. By integrating concepts like resampling, two-stage acquisition, and fine-acquisition, this method enables the attainment of higher accuracy without compromising speed. The results demonstrate that the proposed method enhances accuracy by 7.275% compared to conventional methods and boosts speed by 76.97% compared to methods focused on accuracy improvement.

Physics-constrained adaptive kernel interpolation for region-to-region acoustic transfer function: a Bayesian approach

A kernel interpolation method for the acoustic transfer function (ATF) between regions constrained by the physics of sound while being adaptive to the data is proposed. Most ATF interpolation methods aim to model the ATF for fixed source by using techniques that fit the estimation to the measurements while not taking the physics of the problem into consideration. We aim to interpolate the ATF for a region-to-region estimation, meaning we account for variation of both source and receiver positions. By using a very general formulation for the reproducing kernel function, we have created a kernel function that considers both directed and residual fields as two separate kernel functions. The directed field kernel considers a sparse selection of reflective field components with large amplitudes and is formulated as a combination of directional kernels. The residual field is composed of the remaining densely distributed components with lower amplitudes. Its kernel weight is represented by a universal approximator, a neural network, in order to learn patterns from the data freely. These kernel parameters are learned using Bayesian inference both under the assumption of Gaussian priors and by using a Markov chain Monte Carlo simulation method to perform inference in a more directed manner. We compare all established kernel formulations with each other in numerical simulations, showing that the proposed kernel model is capable of properly representing the complexities of the ATF.

Performance Evaluation of Non-Lambertian SLIPT for 6G Visible Light Communication Systems

Visible light communication (VLC) has emerged as one promising candidate technique to improve the throughput performance in future sixth-generation (6G) mobile communication networks. Due to the limited battery capacity of VLC systems, light energy harvesting has been proposed and incorporated for achieving the simultaneous lightwave information and power transfer (SLIPT) function and for improving the overall energy efficiency. Nevertheless, almost all reported works are limited to SLIPT scenarios adopting a basic and well-discussed Lambertian optical transmitter, which definitely cannot characterize the potential and essential scenarios employing distinctive non-Lambertian optical transmitters with various spatial beam characteristics. For addressing this issue, in this work, SLIPT based on a distinct non-Lambertian optical beam configuration is investigated, and for further enhancing the harvested energy and the achievable data rate, the relevant flexible optical beam configuration method is presented as well. The numerical results show that, for a typical receiver position, compared with about 1.14 mJ harvested energy and a 31.2 Mbps achievable data rate of the baseline Lambertian configuration, a harvested energy gain of up to 1.55 mJ and an achievable data rate gain of 21.1 Mbps can be achieved by the non-Lambertian SLIPT scheme explored here.

Modeling regional occupancy of fishes using acoustic telemetry: a model comparison framework applied to lake trout

Acoustic telemetry is a common tool used in fisheries management to estimate fish space use (i.e., occupancy) from a local habitat scale to entire systems. Numerous analytical models have been developed to estimate different aspects of fish movement from telemetry datasets, yet evaluations of model performance and comparisons among models are limited. Here, we develop a framework to evaluate model estimates of regional occupancy in large and fragmented systems using an acoustic receiver array in Lake Champlain. We simulated the tracks of 100 acoustically tagged fish using a random walk function and created detection events based on receiver positions and distance-based detection probability. Regional occupancy for the simulated data was estimated by six movement models that ranged in analytical complexity, and results were compared to the true distributions for each simulated track to evaluate model error. The six movement models included: (1) a basic residency index using detections alone; (2) a residency index using last-observation-carried-forward; (3) a centers of activity model; (4) linear and non-linear interpolations (i.e., least-cost paths); and (5 and 6) two dynamic Brownian bridge movement models generated using separate packages in R. We developed a model selection process to compare model performance and select the optimal analysis based on simulation error. This process showed significant differences in model performance among the six movement models based on model error. Overall, the model generating least-cost paths using linear and non-linear interpolations consistently provided the most accurate regional occupancy estimates. Based on these simulation results, we applied this model to a case study that evaluated patterns in the regional distribution of stocked lake trout (Salvelinus namaycush) in Lake Champlain, which demonstrated distinct regional occupancy of two stocked lake trout groups. These results demonstrate potential for large variability in interpretation of acoustic telemetry data for describing regional fish distribution dependent on the analytical method used.

Correlation of Player and Imaging Characteristics With Severity and Missed Time in National Football League Professional Athletes With Hamstring Strain Injury: A Retrospective Review

Background: Hamstring strain injuries (HSIs) are prevalent in US National Football League (NFL) players, but there is a paucity of information regarding imaging characteristics, injury severity, and player factors associated with time missed and risk of recurrent injury. Purpose: To describe player, football activity, clinical, and imaging characteristics of NFL players with HSIs, as well as determine player characteristics, clinical examination results, and magnetic resonance imaging (MRI) findings associated with injury occurrence, severity, and missed time. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A retrospective cohort of NFL players with acute HSI (n = 180) during the 2018-2019 season was identified. Injury data were collected prospectively through a league-wide electronic health record system. Three musculoskeletal radiologists graded MRI muscle injury parameters using the British Athletics Muscle Injury Classification (BAMIC) system. Player, football, clinical, and imaging characteristics were correlated with HSI incidence and severity and with missed time from sport. Results: Of the 1098 HSIs identified during the 2018-2019 season, 416 (37.9%) were randomly sampled, and 180 (43.3%) had diagnostic imaging available. Game activity, preseason period, and wide receiver and defensive secondary positions disproportionately contributed to HSI. The biceps femoris was the most commonly injured muscle (n = 132, 73.3%), followed by the semimembranosus (n = 24, 13.3%) and semitendinosus (n = 17, 9.4%) muscles. The most common injury site was the distal third of the biceps femoris and semitendinosus muscles (n = 60, 45.5% and n = 10, 58.8%, respectively) and central part of the semimembranosus muscle (n = 17, 70.8%). Nearly half of the injuries (n = 83, 46.1%) were BAMIC grade 2; 25.6% (n = 46), grade 3; and 17.8% (n = 32), grade 4. MRI showed sciatic nerve abnormality in 30.6% (n = 55) of all HSIs and 81.3% (n = 26) of complete tendon injuries. BAMIC grade correlated with both median days and games missed. Combined biceps femoris and semitendinosus injuries resulted in the highest median days missed (27 days). Conclusion: Among NFL players with acute HSIs, the most common injury was a moderate-severity injury of the distal biceps femoris. BAMIC grade was associated with missed time.

A study of the spatial non-uniformity of reverberation time at low frequencies

This paper presents a study of the spatial non-uniformity of low-frequency reverberation time estimates. Using measured and simulated data, it is demonstrated that the reverberation times estimated from band-limited impulse responses vary as a function of space at low frequencies. The origin of this spatial dependency is investigated using a one-dimensional finite element model. It is shown that the Q-factor and reverberation time at the resonant frequency of a particular mode are spatially dependent and that the spatial dependency is related to the mode shapes. The ranges of the reverberation time estimates as a function of third-octave frequency bands in simulated and measured rooms are presented. An additional finding is that modal damping constants (obtained via eigenvalue analysis) quantify the decay of uncoupled modes but not necessarily the reverberation time. These observations have implications for measurements and simulations of reverberation time at low frequencies. When measuring a spatially averaged reverberation time, the choice of source and receiver positions is important. A guideline is proposed that defines a set of preferred measurement positions based on the mode shapes, from which estimates of the spatially averaged reverberation time can be obtained.

Optimalisasi Penentuan Posisi Access Point Untuk Meminimalisir Area Blankspot Pada Pantai Panrangluhu

This research aims to determine the optimal position of Access Point to reduce blankspot area in Panrangluhu Beach. The research methodology involves several main steps: (1) Research planning is done by collecting important data such as beach plan, Access Point height, location coordinates, distance between points, and RSSI (Received Signal Strength Indicator) value; (2) Access Point and receiver position coordinates are determined in an outdoor environment; (3) RSSI value data received by the receiver is collected using WiFi Signal Meter software. To ensure even network coverage, network quality testing was conducted in the eight cardinal directions at each hotspot point. The results showed that four hotspot points were needed to achieve optimal network coverage throughout the beach area. With this strategic placement, it is expected that there are no areas that are not covered by the network, so that visitors to Panrangluhu Beach can enjoy stable and evenly distributed internet access throughout the beach.

Speech intelligibility evaluation of small-scale mosque with multiple domes design

PurposeMosques are built with dome-shaped ceilings for communal worship with common architectural styles worldwide for prayer. Since the acoustics of worship buildings are just as significant as their aesthetics, they should enhance people’s sense of hearing. This study evaluates the speech intelligibility of a small mosque with multiple domes to determine the space acoustic conditions.Design/methodology/approachThe investigation involved extensive literature reviews to collect relevant data to model the case study. The Enhanced Acoustics Simulator for Engineers (EASE) software program was used to integrate critical parameters such as the absorption coefficient of materials, dome shapes and the number of domes in the simulation. The study employed speech intelligibility parameters such as C50, S.T.I. and %ALcons to assess the acoustic conditions. The assessment model was validated through statistical analysis and a paired t-test.FindingsThe study discovered that varying shapes of the multiple domes showed no significant impact on speech intelligibility. However, different multiple domes materials resulted in significant disparities in speech intelligibility. Applying high-absorption materials in multiple dome designs achieved the most effective acoustic performance. Except for C50 in some circumstances and receiver positions, all other alternatives met the optimal value for overall speech intelligibility because the sound was not sufficiently diffused early on, suggesting that the early reflection sounds were either weak or insufficient.Originality/valueThis study not only helps to determine the multiple-dome effect on mosque acoustics but also empowers archaeoacoustics and historic conservation by documenting these significant places of worship. The findings advocate using high-absorption materials in multiple dome designs and offer practical insight into mosque design material selection. By enhancing the understanding of the acoustic conditions in small-scale mosques, this study equips architects, engineers and builders with the knowledge to create spaces prioritizing speech clarity and intelligibility.

Estimation of Water Velocity and Receiver Position Changes in Time-Lapse Seismic Using Machine Learning

Non-repeatability is one of the main obstacles in time-lapse seismic, as it significantly degrades the interpretation of reservoir-related signals. Correcting the data variations caused by non-repeatability (4D noise) is of paramount importance, which usually requires the estimation of the changing parameter. ln this paper, we propose a Machine Learning (ML) workflow for the quantitative estimation of two types of 4D noise: changes in the speed of sound in water and receiver lateral positions. A synthetic database, modeled from a velocity model estimated from the Brazilian pre-salt, and containing many time-lapse seismic surveys was generated for the supervised training of ML models. lnput samples consist of subsets of common-shot seismograms. We studied many combinations of ML regression algorithms and feature extraction techniques, for scenarios where data is contaminated, or not, with Gaussian random noise. The regression algorithms considered were Fully-Connected Neural Network, Extreme Gradient Boosting, and Bayesian Ridge. Four rectangular crops of the common-shot seismogram were tested as input features: full seismogram, first half of time samples, 11 smallest-offset traces, and the time samples focusing on the first arrivals region. The combination with the best trade-off between accuracy and model complexity is the Bayesian Ridge fed with the 11 smallest-offset traces, which estimated position and velocity time-lapse changes with median accuracy of 0.115 m and 0.017 m/s for the case with Gaussian noise. Besides the correction of repeatability-related variations, our results are useful in the 4D Full-Waveform lnversion which needs accurate parameters to produce good seismic images.

TDOA and FDOA Hybrid Positioning of Mobile Radiation Source with Receiver Position Errors

TDOA and FDOA Hybrid Positioning of Mobile Radiation Source with Receiver Position Errors

Regional soundscape modeling of the Atlantic Outer Continental Shelfa).

The ocean soundscape is a complex superposition of sound from natural and anthropogenic sources. Recent advances in acoustic remote sensing and marine bioacoustics have highlighted how animals use their soundscape and how the background sound levels are influenced by human activities. In this paper, developments in computational ocean acoustics, remote sensing, and oceanographic modeling are combined to generate modelled sound fields at multiple scales in time and space. Source mechanisms include surface shipping, surface wind, and wave fields. A basin scale model is presented and applied to the United States Atlantic Outer Continental Shelf (OCS). For model-data comparison at a single hydrophone location, the model is run for a single receiver position. Environmental and source model uncertainty is included in the site-specific modeling of the soundscape. An inversion of the local sediment type is made for a set of sites in the OCS. After performing this inversion, the qualitative comparison of the modelled sound pressure level (SPL) time series and observed SPL is excellent. The quantitative differences in the mean root mean square error between the model and data is less than 3 dB for most sites and frequencies above 90 Hz.

High-Resolution Yield Mapping for Eucalyptus grandis—A Case Study

Yield data represent a valuable layer for supporting decision-making as they reflect crop management results. Forestry decision-makers often rely on coarse spatial resolution data (e.g., forest inventory plots) despite the availability of modern harvesters that can provide high-resolution forestry yield data. The objectives of this study were to present a method for generating high-resolution Eucalyptus grandis yield data (individual tree-level) and explore their applications, such as correlation analysis with soil attributes to aid nutrient recommendations. Two evaluations were conducted at two sites in Brazil: (a) assessing the positioning accuracy of the global navigation satellite system (GNSS) receiver positioning, and (b) analyzing the yield data and their correlation with the soil attributes. The results indicated that positioning the GNSS receiver at the harvesting head provided higher accuracy than placement at the top of the harvester cabin for individual tree-level data. Reliable yield data were generated despite the GNSS receiver’s increased susceptibility to damage when mounted on a harvest head. The linear correlation analysis between the Eucalyptus grandis yield data and soil attributes showed both negative (Clay, B, S, coarse sand, and potential acidity − H + Al) and positive correlations (K, Mg, pH-SMP, Ca, sum of bases, pH, base saturation, fine sand, total sand, and silt content). This study demonstrates the feasibility of obtaining high-resolution yield data at the individual tree-level and their correlation with soil attributes, providing valuable insights for improving forestry decision-making.

Realistic ray-tracing model of a Scheffler reflector based on experimental data

A model of a Scheffler reflector with mirror facets is presented in the form of an open-source script for use with the free ray-tracing software Soltrace (Monte-Carlo method). It is calibrated to match the experimental results obtained with an 8 m2 (surface area) reflector of 1.43 m focal distance. It is found that the optical errors of real reflectors (slope, specularity, shape) are very large, leading to results that are far from theoretical. A sensitivity study is then carried out to assess the level of importance of reflector and receiver positioning and adjustment to obtain maximum performance. The parametric study showed that the margin of error is quite small for north–south alignment, rotation axis adjustment, horizontal receiver position, declination adjustment and tracking system, with a performance reduction of 10% for errors of 1°, 0.8°, 6 cm, 2 days and 4 min, respectively. The inclination of the receiver has lower influence on the results. The performance of Scheffler reflectors could therefore be greatly enhanced by improving the shape and characteristics of the mirrors, taking particular care with the various settings. In addition, as an application example, a secondary optical system multiplying the power density by up to 3.3 is proposed.

Simplified channel model for indoor VLC systems.

The channel model of indoor visible light communication (VLC) is primarily influenced by the receiver's position and orientation. In this study, we decouple the effects of receiver position and orientation, treating them as independent random variables. This decoupling enables a clearer understanding of how each factor independently influences the channel model. Specifically, we focus on the impact of the azimuth angle, a critical component of orientation, on the VLC channel. We present a simplified channel model for indoor VLC systems based on partial orientation information. Theoretical analysis and simulation results collectively indicate that the accuracy of the simplified channel model is influenced by the field-of-view (FOV), with higher accuracy achieved at narrower FOVs. To evaluate practical performance, we compare our simplified model with the existing complete channel model in a two-user precoding system. Results show that our proposed simplified channel model maintains value, particularly in narrow-FOV scenarios. The research findings indicate that this simplified model is suitable for applications with high demands for channel accuracy in narrow-FOV indoor VLC systems, and can be extended to applications in wide-FOV systems where perfect channel information is not required.