Boundedness in temporal and spatial domains

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Betka Sophie ◽  
Łukowska Marta ◽  
Silva Marta ◽  
King Joshua ◽  
Garfinkel Sarah ◽  
...  

AbstractMany interoceptive tasks (i.e. measuring the sensitivity to bodily signals) are based upon heartbeats perception. However, the temporal perception of heartbeats—when heartbeats are felt—varies among individuals. Moreover, the spatial perception of heartbeats—where on the body heartbeats are felt—has not been characterized in relation to temporal. This study used a multi-interval heartbeat discrimination task in which participants judged the timing of their own heartbeats in relation to external tones. The perception of heartbeats in both time and spatial domains, and relationship between these domains was investigated. Heartbeat perception occurred on average ~ 250 ms after the ECG R-wave, most frequently sampled from the left part of the chest. Participants’ confidence in discriminating the timing of heartbeats from external tones was maximal at 0 ms (tone played at R-wave). Higher confidence was related to reduced dispersion of sampling locations, but Bayesian statistics indicated the absence of relationship between temporal and spatial heartbeats perception. Finally, the spatial precision of heartbeat perception was related to state-anxiety scores, yet largely independent of cardiovascular parameters. This investigation of heartbeat perception provides fresh insights concerning interoceptive signals that contribute to emotion, cognition and behaviour.


2021 ◽  
Vol 13 (6) ◽  
pp. 1144
Author(s):  
Mahendra Bhandari ◽  
Shannon Baker ◽  
Jackie C. Rudd ◽  
Amir M. H. Ibrahim ◽  
Anjin Chang ◽  
...  

Drought significantly limits wheat productivity across the temporal and spatial domains. Unmanned Aerial Systems (UAS) has become an indispensable tool to collect refined spatial and high temporal resolution imagery data. A 2-year field study was conducted in 2018 and 2019 to determine the temporal effects of drought on canopy growth of winter wheat. Weekly UAS data were collected using red, green, and blue (RGB) and multispectral (MS) sensors over a yield trial consisting of 22 winter wheat cultivars in both irrigated and dryland environments. Raw-images were processed to compute canopy features such as canopy cover (CC) and canopy height (CH), and vegetation indices (VIs) such as Normalized Difference Vegetation Index (NDVI), Excess Green Index (ExG), and Normalized Difference Red-edge Index (NDRE). The drought was more severe in 2018 than in 2019 and the effects of growth differences across years and irrigation levels were visible in the UAS measurements. CC, CH, and VIs, measured during grain filling, were positively correlated with grain yield (r = 0.4–0.7, p < 0.05) in the dryland in both years. Yield was positively correlated with VIs in 2018 (r = 0.45–0.55, p < 0.05) in the irrigated environment, but the correlations were non-significant in 2019 (r = 0.1 to −0.4), except for CH. The study shows that high-throughput UAS data can be used to monitor the drought effects on wheat growth and productivity across the temporal and spatial domains.


2021 ◽  
Author(s):  
Yoni Stern ◽  
Inbar Ben-Yehuda ◽  
Danny Koren ◽  
ADAM ZAIDEL ◽  
Roy Salomon

The feeling of control over one’s actions, termed the Sense of Agency (SoA), delineates one’s experience as an embodied self. Although, this embodied experience is typically perceived as stable over time, recent theoretical accounts highlight the experience-dependent and dynamic nature of the embodied self. In this study we examined how recent experiences modulate SoA (i.e., serial dependence), and disambiguated the unique contributions of previous stimuli and choices on subsequent SoA judgments. In addition, we examined whether these effects persist across different domains of perceptual alteration. We analyzed two independent datasets of the Virtual Hand (VH) task (N = 100 participants) in which a sensorimotor conflict is introduced between the presented visual feedback and the actual movement performed. In Dataset 1, which included only temporal alterations, we found that previous stimuli recalibrate current perception, increasing the likelihood of the current choice to be different than the previous choice. Whereas previous choices induce a repetition bias increasing the likelihood to repeat choices across trials. Thus, previous external stimuli and self-generated choices exert opposing influences on SoA. We replicated these findings in Dataset 2, in which the VH task was tested with alterations in both temporal and spatial domains. In addition, we discovered that previous stimuli from a different perceptual domain exert a recalibration effect similar to stimuli from the same domain. Thus, SoA is constantly shaped by our previous subjective choices and objective stimuli experienced even across different perceptual domains. This highlights how SoA may act as unifying construct organizing our experience of the self over time and across perceptual experiences.


Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3377
Author(s):  
Dan Zhao ◽  
Lian Feng

The first geostationary ocean color satellite mission (geostationary ocean color imager, or GOCI) has provided eight hourly observations per day over the western Pacific region since June 2010. GOCI imagery has been widely used to track the short-term dynamics of coastal and inland waters. Few studies have been performed to comprehensively assess the advantages of GOCI images in obtaining valid observations and estimating diurnal changes within the water column. Using the entire mission dataset between 2011 and 2017, these knowledge gaps were filled by comparing the daily percentages of valid observations (DPVOs) between GOCI and MODIS Aqua (MODISA) and by examining the diurnal changes in Chl-a over the East China Sea. The mean DPVOs of GOCI was 152.6% over the clear open ocean, suggesting that a daily valid coverage could be expected with GOCI. The GOCI DPVOs were ~26 times greater than the MODISA DPVOs; this pronounced difference was caused by the combined effects of their different observational frequencies and the more conservative quality flag system for MODISA. Diurnal changes in the GOCI-derived Chl-a were also found, with generally higher Chl-a in the afternoon than the morning and pronounced heterogeneities in the temporal and spatial domains. However, whether such diurnal changes are due to the real dynamics of the oceanic waters or artifacts of the satellite retrievals remains to be determined. This study provides the first comprehensive quantification of the unparalleled advantages of geostationary ocean color missions over polar orbiters, and the results highlights the importance of geostationary ocean color missions in studying coastal and inland waters.


Author(s):  
Vaahini Ganesan ◽  
Tuhin K. Das ◽  
Jeffrey L. Kauffman ◽  
Nazanin Rahnavard

Vibration-based monitoring of mechanical structures often involves continuous monitoring that result in high data volume and instrumentation with a large array of sensors. Previously, we have shown that Compressive Sensing (CS)-based vibration monitoring can significantly reduce both volume of data and number of sensors in temporal and spatial domains respectively. In this work, further analysis of CS-based detection and localization of structural changes is presented. Incorporating damping and noise handling in the CS algorithm improved its performance for frequency recovery. CS-based reconstruction of deflection shape of beams with fixed boundary conditions is addressed. Formulation of suitable bases with improved conditioning is explored. Restricting hyperbolic terms to lower frequencies in the basis functions improves reconstruction. An alternative is to generate an augmented basis that combines harmonic and hyperbolic terms. Incorporating known boundary conditions into the CS problem is studied.


Author(s):  
Mojtaba Oghbaei ◽  
Kurt S. Anderson ◽  
John A. Evans

This paper outlines the parallel implementation of a newly developed multibody system dynamics formulation. The methodology provides the means for the dynamic simulation to be parallelized temporally as well as spatially which will allow better exploitation of anticipated massively parallel computing resources. This will have three advantages: First, the system of equations may now be coarse grain parallelized to a far greater degree allowing an increased number of processors to be effectively utilized. Secondly, this will significantly reduce the fraction of serial operations and thus should increase speedup (reduced turn-around). Finally, the method allows temporal scale of each variable to be adjusted independently and as such offer considerable advantage for the efficient and accurate modeling and simulation of multiscale behaviors. These gains can be accomplished by discretizing a special form of the equations of motion in both temporal and spatial domains. Examples are provided to clarify the application of this scheme with particular attention on time domain parallelization.


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