Orientation In Space Research Articles

Online position correction approach of an industrial robot by using a new photogrammetric measurement system

Six-axis industrial robots are widely used, mainly because of their versatility. However, they have one drawback: they are not as accurate as conventional machine tools. There are currently a number of approaches to increase the accuracy of these robots. This paper reports on the online correction of an ABB IRB 120 industrial robot using a novel photogrammetric measurement device, the Multi Aperture Positioning System (MAPS). As described by Luhmann, multi-camera solutions were previously required for the online measurement of the six degrees of freedom (6DOF = position and orientation in 3D space) of the robot TCP. MAPS offers the advantages of a single-camera system and at the same time the features and accuracy of a multi-camera system. To increase the accuracy of the robot, a correction algorithm is developed. It uses the measured values from MAPS to calculate the deviation of the robot Tool Center Point (TCP) position from the planned position and corrects it online if necessary. In this paper, three experiments are presented and their results discussed. Two to determine the position and trajectory accuracy of the robot and one to determine its z-stability on a trajectory in the xy plane. In each of these experiments, the robot end effector is tracked with the MAPS measurement device. After the actual state of the robot was recorded, all experiments were performed again, this time with the online correction. In all experiments, a significant increase in the accuracy of the robot can be observed. For example, the mean absolute error (MAE) of the position accuracy improved by a factor of 7 from 0.0207 to 0.0029 mm and the path accuracy (MAE) from 0.1140 to 0.0151 mm.

Method on pose estimation of excavators based on onboard depth camera

Pose estimation of construction machines describes their motions and orientations in 3D space, which provides basic information for remote control, safety monitoring, and productivity analysis. Among the commonly used construction machines, the excavator is an important one whose pose information has significant value in the development of automatic driving systems and operation safety monitoring. Regarding vision-based pose estimation of excavators, previous studies mainly rely on image data from digital cameras installed on sites. However, their robustness may drop due to occlusions by surrounding clutters. To address these problems fundamentally, this study proposes a method on partial pose estimation of excavators, with an onboard depth camera installed on the cabin of the targeted excavator. This solution is inspired by the visual effect produced by the operator’s eyes, according to the Bionics principles. First, by processing the depth camera data, the spatial coordinates of several pre-defined keypoints of an excavator are obtained. Afterward, by combining the keypoint coordinates with prior knowledge of the geometric relationship of excavators, a pose triangle is computed which describes the pose of the excavator. Finally, the feasibility of the proposed algorithm is preliminarily verified by experimental data from real construction sites. This study contributes not only to solve the problem of occlusion when using visual sensors on sites, but also to provide a theoretical basis for the design of onboard control systems for excavators.

Composite Spatial Manipulation Framework for Redirected Walking

In this study, we present a composite spatial manipulation framework for the redirected walking technique. The proposed framework focuses on utilizing two different approaches simultaneously to manipulate the user’s position and orientation in the physical space, aiming to substantially improve their redirection in a confined physical space and reduce the special requirements for the RDW technique. Each approach utilizes different perceptual processes. The first is a discrete spatial manipulation approach that introduces translation and/or rotation gains to the user’s virtual perspective in the immersive virtual environment (IVE) during temporal events such as eyeblinks. The second approach is the continuous spatial manipulation approach, which continuously introduces (with each frame) translation and/or rotation gains below the user’s perception threshold to their virtual perspective in the IVE. Two simulation experiments were conducted to investigate the feasibility of adopting the composite spatial manipulation framework for RDW without considering the user’s walking behavior or the impact of the proposed approach on user performance in the immersive virtual environment. In the second simulation experiment we aimed to investigate the performance of the proposed approach while considering the user’s walking behavior and performance in the IVE. Finally, a user experiment was conducted to validate the proposed framework and its impact on the user’s performance in the IVE. The findings revealed a significant improvement in the redirection performance of the proposed controller when it was compared to the classical RDW controller. Additionally, there was significant improvement in the user’s performance when the composite RDW controller was utilized.

The Return of Neighborhood Space in the Context of Urban Renewal

With the intensification of urban construction and urbanization, there is a positive picture across the country. However, with the spread of “urban disease”, the supporting facilities of cities and the quality of life of residents are relatively weakened. Through the discussion of the space loss of urban neighborhood interface caused by land policy under modern transformation and marketization, the negative reasons of urban neighborhood space and the importance of transforming it into positive space to promote its return are analyzed from multiple levels. According to the relevant basic elements, the basic constraints of the urban neighborhood interface are analyzed, the function and conceptual orientation of the urban interface space are expounded, and finally the regression strategy of the lost space of the urban adjacent interface is given.

A New Radar Echo Generation Model for Ultra-Low Altitude Targets in Far-Field Conditions

This paper proposed a new radar echo simulation method for ultra-low altitude targets in far-field conditions. Based on the electromagnetic (EM) scattering calculation of target and environment, combined with the weighted four-path model, the scattering data of target, environment, and multipath are obtained. The Range-Doppler ring partitioning method is used to determine the size of the minimum resolution units, and then the environment is divided into several scattering elements. By using the method of temporal decomposition, the wide-time pulse is decomposed into a plurality of narrow pulse signals, and the narrow pulses act on scattering elements with different distances and orientations in space. The total echo is obtained by a linear superposition of the responses of each scattering unit. In addition, the numerical results with different parameters, including signal bandwidths, target types, and target height, are simulated and analysed. The simulation results demonstrate that the proposed method can provide a better description of the scattering characteristics of sea-skimming targets in complex scenes in far-field conditions. Meanwhile, it can be applied to the detection and recognition of ultra-low altitude targets above the sea surface.

Experimental approaches to modeling delirium in zebrafish (<i>Danio rerio</i>)

Delirium is an acute psychiatric syndrome characterized by impaired attention, perception and orientation in space. Albeit known for millennia, the mechanisms and risk factors of delirium remain poorly understood. Experimental animal models, especially rodents, become widely used to understand these pathogenetic aspects. However, a new model organism zebrafish (Danio rerio) also has promise in this field. Discussed here, recent behavioral tests and protocols for zebrafish enable assessing their behavioral and cognitive function, and its experimental modulation by deliriant drugs and other factors.

Synthesis and Characterization of Novel Sprayed Ag-Doped Quaternary Cu2MgSnS4 Thin Film for Antibacterial Application.

In this work, the effects of silver doping with different Ag/(Ag + Cu) ratios (i.e., 2%, 5% and 10% at.% in the spray solution) on the structural, morphological, optical, electrical and antibacterial properties of Cu2MgSnS4 (CMTS) thin film grown by spray pyrolysis have been studied. The X-ray diffraction (XRD) and selected area electron diffraction (SAED) results have shown that the kesterite phase of CMTS thin films has a maximum crystallite size of about 19.60 nm for 5% Ag/(Ag + Cu). Scanning electron microscopy (SEM) images have shown spherical grain shapes. The transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) microscopy observations confirmed the intrinsic reticular planes of CMTS thin film with (112) as a preferred orientation and interplanar spacing value of 3.1 Å. The optical properties showed high absorbance and an absorption coefficient of about 104 cm−1 in the visible region with an optical band gap energy of 1.51 eV. Impedance analysis spectroscopy demonstrated good electrical properties of the CMTS film obtained using 5% Ag/(Ag + Cu). The antibacterial activity of the undoped and Ag-doped particles of CMTS obtained using 5% Ag/(Ag + Cu) against different strains of pathogenic bacteria was tested using the agar well diffusion method. These results showed a significant antibacterial activity of the Ag-doped CMTS particle, which was much higher than the undoped CMTS particles. These experimental findings may open new practices for the Ag-doped CMTS compound, especially the one obtained using 5% Ag/(Ag + Cu), in antibacterial application.

Asteroid spin-states of a 4 Gyr collisional family

Context. Families of asteroids generated by the collisional fragmentation of a common parent body have been identified using clustering methods of asteroids in their proper orbital element space. However, there is growing evidence that some of the real families are larger than the corresponding cluster of objects in orbital elements, and there are families that escaped identification by clustering methods. An alternative method has been developed in order to identify collisional families from the correlation between the asteroid fragment sizes and their proper semi-major axis distance from the family centre (V-shape). This method has been shown to be effective in the cases of the very diffuse families that formed billions of years ago. Aims. Here we use multiple techniques for observing asteroids to provide corroborating evidence that one of the groups of asteroids identified as a family from the correlation between size and proper semi-major axis of asteroids are real fragments of a common parent body, and thus form a collisional family. Methods. We obtained photometric observations of asteroids in order to construct their rotational light curves; we combine them with the literature light curves and sparse-in-time photometry; we input these data in the light curve inversion methods, which allow us to determine a convex approximation to the 3D shape of the asteroids and their orientation in space, from which we extract the latitude (or obliquity) of the spin pole in order to assess whether an object is prograde or retrograde. We included in the analysis spin pole solutions already published in the literature aiming to increase the statistical significance of our results. The ultimate goal is to assess whether we find an excess of retrograde asteroids on the inward side of the V-shape of a 4 Gyr asteroid family identified via the V-shape method. This excess of retrograde rotators is predicted by the theory of asteroid family evolution. Results. We obtained the latitude of the spin poles for 55 asteroids claimed to belong to a 4 Gyr collisional family of the inner main belt that consists of low-albedo asteroids. After re-evaluating the albedo and spectroscopic information, we found that nine of these asteroids are interlopers in the 4 Gyr family. Of the 46 remaining asteroids, 31 are found to be retrograde and 15 prograde. We also found that these retrograde rotators have a very low probability (1.29%) of being due to random sampling from an underlying uniform distribution of spin poles. Conclusions. Our results constitute corroborating evidence that the asteroids identified as members of a 4 Gyr collisional family have a common origin, thus strengthening their family membership.

Well-Posedness of an Integro-Differential Model for Active Brownian Particles

We propose a general strategy for solving nonlinear integro-differential evolution problems with periodic boundary conditions, where no direct maximum/minimum principle is available. This is motivated by the study of recent macroscopic models for active Brownian particles with repulsive interactions, consisting of advection-diffusion processes in the space of particle position and orientation. We focus on one of such models, namely a semilinear parabolic equation with a nonlinear active drift term, whereby the velocity depends on the particle orientation and angle-independent overall particle density (leading to a nonlocal term by integrating out the angular variable). The main idea of the existence analysis is to exploit a-priori estimates from (approximate) entropy dissipation. The global existence and uniqueness of weak solutions is shown using a two-step Galerkin approximation with appropriate cutoff in order to obtain nonnegativity, an upper bound on the overall density and preserve a-priori estimates. Our anyalysis naturally includes the case of finite systems, corresponding to the case of a finite number of directions. The Duhamel principle is then used to obtain additional regularity of the solution, namely continuity in time-space. Motivated by the class of initial data relevant for the application, which includes perfectly aligned particles (same orientation), we extend the well-posedness result to very weak solutions allowing distributional initial data with low regularity.

SGM3D: Stereo Guided Monocular 3D Object Detection

Monocular 3D object detection aims to predict the object location, dimension and orientation in 3D space alongside the object category given only a monocular image. It poses a great challenge due to its ill-posed property, which is a critical lack of depth information in the 2D image plane. While existing approaches leverage off-the-shelf depth estimation or rely on LiDAR sensors to mitigate this problem, dependence on the additional depth model or expensive equipment severely limits their scalability to generic 3D perception. In this paper, we propose a stereo-guided monocular 3D object detection framework, dubbed SGM3D, which aligns the monocular feature to the stereo feature and exploits the network's ability of generating the cross-modal feature for accurate 3D object detection. We present a multi-granularity feature alignment (MG-FA) mechanism to exploit the network's ability to generate stereo-mimicking features given only monocular cues. Coarse feature-level, as well as fine anchor-level feature alignment, are both leveraged for monocular feature guidance. In addition, we introduce an IoU matching-based feature alignment (IoU-MA) method for object-level feature alignment between the stereo and monocular predictions to alleviate the mismatches while adopting the MG-FA. Extensive experiments on the KITTI datasets demonstrate the effectiveness of our method. Code is publicly available at <uri xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">https://github.com/zhouzheyuan/sgm3d</uri> .

Movement preferences of the wrist and forearm during activities of daily living

BackgroundDuring activities of daily living, the main degrees of freedom of the forearm and wrist—forearm pronation-supination (PS), wrist flexion-extension (FE), and wrist radial-ulnar deviation (RUD)—combine seamlessly to allow the hand to engage with and manipulate objects in our environment. Yet the combined behavior of these three degrees of freedom is relatively unknown. PurposeTo provide a characterization of natural forearm and wrist kinematics (joint configuration, movement direction, and speed) during activities of daily living. Study designThis is a descriptive cross-sectional study. MethodsTen healthy subjects performed 24 activities of daily living chosen to represent a wide variety of activities, while we measured their PS, FE, and RUD angles using electromagnetic motion capture. The orientation of the forearm and wrist was represented in the three-dimensional “configuration space” spanned by PS, FE, and RUD. From the time course of forearm and wrist orientation in configuration space, we extracted three-dimensional distributions of joint configuration, movement direction, and speed. ResultsMost joint configurations were focused in a relatively small area: subjects spent roughly 50% of the time in the central 20% of their functional range of motion. Some movement directions were significantly more common than others (p < 0.001); in particular, the direction of the dart-thrower's motion (DTM) was about three times more common than motion perpendicular to it. Most movements were slow: the likelihood of moving at increasing speeds dropped off exponentially. Interestingly, the most common high-speed motion combined the DTM with a twist from pronation to supination. As this motion allows one to pick up an object in front of one's body and bring it to the head, it is essential for self-care. Thus, although many activities of daily living follow the DTM without significant forearm rotation, the greatest importance of the DTM may lie in its combination with forearm rotation. ConclusionsDespite the wide variety of activities, we found evidence of preferred movement behavior, and this behavior showed significant coupling between the wrist and forearm.

Early blindness modulates haptic object recognition.

Haptic object recognition is usually an efficient process although slower and less accurate than its visual counterpart. The early loss of vision imposes a greater reliance on haptic perception for recognition compared to the sighted. Therefore, we may expect that congenitally blind persons could recognize objects through touch more quickly and accurately than late blind or sighted people. However, the literature provided mixed results. Furthermore, most of the studies on haptic object recognition focused on performance, devoting little attention to the exploration procedures that conducted to that performance. In this study, we used iCube, an instrumented cube recording its orientation in space as well as the location of the points of contact on its faces. Three groups of congenitally blind, late blind and age and gender-matched blindfolded sighted participants were asked to explore the cube faces where little pins were positioned in varying number. Participants were required to explore the cube twice, reporting whether the cube was the same or it differed in pins disposition. Results showed that recognition accuracy was not modulated by the level of visual ability. However, congenitally blind touched more cells simultaneously while exploring the faces and changed more the pattern of touched cells from one recording sample to the next than late blind and sighted. Furthermore, the number of simultaneously touched cells negatively correlated with exploration duration. These findings indicate that early blindness shapes haptic exploration of objects that can be held in hands.

Sex differences in cognition following variations in endocrine status.

Spatial memory, mediated primarily by the hippocampus, is responsible for orientation in space and retrieval of information regarding location of objects and places in an animal's environment. Since the hippocampus is dense with steroid hormone receptors and is capable of robust neuroplasticity, it is not surprising that changes in spatial memory performance occur following a variety of endocrine alterations. Here, we review cognitive changes in both spatial and nonspatial memory tasks following manipulations of the hypothalamic-pituitary-adrenal and gonadal axes and after exposure to endocrine disruptors in rodents. Chronic stress impairs male performance on numerous behavioral cognitive tasks and enhances or does not impact female cognitive function. Sex-dependent changes in cognition following stress are influenced by both organizational and activational effects of estrogen and vary depending on the developmental age of the stress exposure, but responses to gonadal hormones in adulthood are more similar than different in the sexes. Also discussed are possible underlying neural mechanisms for these steroid hormone-dependent, cognitive effects. Bisphenol A (BPA), an endocrine disruptor, given at low levels during adolescent development, impairs spatial memory in adolescent male and female rats and object recognition memory in adulthood. BPA's negative effects on memory may be mediated through alterations in dendritic spine density in areas that mediate these cognitive tasks. In summary, this review discusses the evidence that endocrine status of an animal (presence or absence of stress hormones, gonadal hormones, or endocrine disruptors) impacts cognitive function and, at times, in a sex-specific manner.

The Mythology of Time in Modern Foreign period dramas: between Retrotopia and Metamodern Sensibility

. The purpose of this article is to analyze the specifics of the mythologizing of time in the historical period dramas "Downton Abbey" and "The Crown" in the context of the transition from the postmodern paradigm to a new metamodern sensibility. The article summarizes the experience of domestic and foreign studies of the metamodern tendencies of the modern TV series and analyzes the theoretical issues of the mythological temporality of TV series production. On the basis of the theoretical concept of retrotopia by Z. Bauman, the concept of layers of cinematic temporality by N.E. Marievskaya and the critical discourse analysis of S. J&amp;#228;ger, the features of the mythologization of horizontal, vertical time, as well as the biographical time of characters in selected period dramas have been analyzed. The scientific novelty of the article lies in the problematization and analysis of the discursive environment of the deployment of the temporal mythology of the modern period drama. The modern historical period drama demonstrates the specifics of turning to retrotopia, as it seeks to represent the current problems of the present through an imaginary past. In the case of the “Downton Abbey”, this happens through the harmonization in the viewer's mind of nostalgia for an imaginary English aristocratic past and an unstable future. In the case of the “The Crown”, the presentation of the private life of the British royal family against the backdrop of historical events contributes to the formation of a more multidimensional image of the present and responds to the demands of the mass audience in the emotional representation of historical events. The result of this representation is a kind of mythology of time, which arises between the cultural demand for retrotopia and the development of modern technologies for the production of cinematographic products, which makes it possible to fully realize the intention of modern metamodernist discourse to achieve a “new sensibility”. This allows us to consider the modern historical period drama not only as a "commercial project", but also as a tool for the development of historical culture, an instrument of cultural orientation in social space and time.

EEG coherence as a marker of functional connectivity disruption in Alzheimer's disease

Progressive deterioration of connectivity between neurons is a neurophysiological hallmark of brain ageing and has been linked to the severity of dementia. We explored the possibility of utilizing electroencephalographic evidence of functional connectivity disruption as a potential marker of Alzheimer's disease. This study examined group differences in EEG coherence within global cortical networks at rest and during executive challenges among patients with Alzheimer's dementia, individuals with mild cognitive impairment, and healthy controls. Four promising EEG coherence markers were identified as (i) F3-F4 Beta in visual-spatial orientation task (p = 0.019), (ii) P7-P8 Beta in writing task (p = 0.001), (iii) T7-T8 Gamma in speech understanding task (p = 0.008) and (iv) O1-O2 Alpha in space orientation task (p = 0.020). More research is needed to identify the sensitivity and specificity of the markers.

A novel guideline for the analysis of linear acceleration mechanics – outlining a conceptual framework of ‘shin roll’ motion

ABSTRACT Linear acceleration is a key performance determinant and major training component of many sports. Although extensive research about lower limb kinetics and kinematics is available, consistent definitions of distinctive key body positions, the underlying mechanisms and their related movement strategies are lacking. The aim of this ‘Method and Theoretical Perspective’ article is to introduce a conceptual framework which classifies the sagittal plane ‘shin roll’ motion during accelerated sprinting. By emphasising the importance of the shin segment’s orientation in space, four distinctive key positions are presented (‘shin block’, ‘touchdown’, ‘heel lock’ and ‘propulsion pose’), which are linked by a progressive ‘shin roll’ motion during swing-stance transition. The shin’s downward tilt is driven by three different movement strategies (‘shin alignment’, ‘horizontal ankle rocker’ and ‘shin drop’). The tilt’s optimal amount and timing will contribute to a mechanically efficient acceleration via timely staggered proximal-to-distal power output. Empirical data obtained from athletes of different performance levels and sporting backgrounds are required to verify the feasibility of this concept. The framework presented here should facilitate future biomechanical analyses and may enable coaches and practitioners to develop specific training programs and feedback strategies to provide athletes with a more efficient acceleration technique.

Trastorno psicótico en paciente con infección activa por SARS-CoV-2: reporte de caso

Se presenta el caso de una mujer adulta joven hospitalizada con neumonía grave por SARS-CoV-2, durante su hospitalización desarrolla psicosis caracterizada por un inicio súbito, ideas delirantes de daño y alucinaciones fluctuantes; paciente conservó la orientación en tiempo, espacio y persona. Los factores predisponentes que se encontraron para este cuadro fueron el aislamiento y la afectación somática secundaria a la enfermedad por SARS-CoV-2. El cuadro remitió al mes de terapia farmacológica. Se realizó una revisión bibliográfica de la fisiopatología, presentación clínica, diagnóstico, factores de riesgo, evolución y tratamiento de los trastornos neuropsiquiátricos en pacientes con COVID-19.

Stabilization control of 3-DOF parallel vessel-borne platform with dynamic uncertainties and unknown disturbances

The wave-induced vessel motions inevitably affect and even menace the operation of onboard equipment, such as excavators, cranes and drilling configurations. Vessel-borne stabilization platforms as a vessel motion compensation device can provide a good solution scheme for the safe offshore operation in tough environmental conditions. To compensate the wave-induced vessel motions in roll, pitch and heave degrees of freedom, this paper proposes a novel stabilization control scheme for a three degrees of freedom parallel vessel-borne platform with dynamic uncertainties and unknown time-varying disturbances. Here the conventional super-twisting algorithm is innovatively modified to mitigate its inherent chattering whereby a new adaptive super-twisting extended state observer (STESO) is constructed to realize the finite-time estimates of the total disturbances lumped by dynamic uncertainties and unknown time-varying disturbances of the vessel-borne platform without relying on any prior knowledge of its upper bounds. Further, a novel adaptive super-twisting sliding mode (STSM) control law with the adaptive STESO is designed to stabilize vessel-borne platforms at a desired position and orientation in the inertial space. The simulation results on a benchmark platform indicate that the wave-induced vessel motions can be compensated by the platform for more than 98% in both 0.5m and 2.5m significant wave heights, such that the workability and safety during offshore activities in tough environmental conditions is increased.

РИТМИКО-ДВИГАТЕЛНОТО ВЪЗПИТАНИЕ НА ДЕТЕТО – СТЪПКА КЪМ ЦЯЛОСТНО РАЗБИРАНЕ НА СВЕТА

The report looks at the role of rhythmic upbringing in age up to 10 years. Movements, rhythmic games and dances of different peoples support children’s development, develop musical abilities, have a nurturing character and create the opportunity for orientation in space, coordination of movements, tolerance and empathy in communication. Through movements and games, the search and discovery of diverse information is stimulated, the child is prompted to ask questions and make connections between different elements of the same phenomenon or process. This stimulates the integrity of perception and understanding of the connections between the elements of an object. Rhythmic upbringing is necessary for the general upbringing of children.

Phase Separation in Systems of Interacting Active Brownian Particles

The aim of this paper is to discuss the mathematical modeling of Brownian active particle systems, a recently popular paradigmatic system for self-propelled particles. We present four microscopic models with different types of repulsive interactions between particles and their associated macroscopic models, which are formally obtained using different coarse-graining methods. The macroscopic limits are integro-differential equations for the density in phase space (positions and orientations) of the particles and may include nonlinearities in both the diffusive and advective components. In contrast to passive particles, systems of active particles can undergo phase separation without any attractive interactions, a mechanism known as motility-induced phase separation (MIPS). We explore the onset of such a transition for each model in the parameter space of occupied volume fraction and P\'eclet number via a linear stability analysis and numerical simulations at both the microscopic and macroscopic levels. We establish that one of the models, namely the mean-field model which assumes long-range repulsive interactions, cannot explain the emergence of MIPS. In contrast, MIPS is observed for the remaining three models that assume short-range interactions that localize the interaction terms in space.