Part Of Representation Research Articles

Embodying an artificial hand increases blood flow to the investigated limb [version 3; peer review: 2 approved

BackgroundThe autonomic nervous system is the main determinant of the blood flow directed towards a body part, and it is tightly connected to the representation of the body in the brain; would the experimental modulation of the sense of limb ownership affect its blood perfusion?MethodsIn healthy participants, we employed the rubber hand illusion paradigm to modulate limb ownership while we monitored the brachial artery blood flow and resistance index within the investigated limb.ResultsIn all conditions with brush-stroking, we found an initial drop in the blood flow due to tactile stimulation. Subsequently, in the illusion condition (where both the rubber and real hand synchronous brush-stroking were present), the blood flow rose significantly faster and reached significantly higher values. Moreover, the increase in blood flow correlated with the extent of embodiment as measured by questionnaires and correlated negatively with the change of peripherical vascular resistance.ConclusionsThese findings suggest that modulating the representation of a body part impacts its blood perfusion.

The string little algebra

We consider the string, like point particles and branes, to be an irreducible representation of the semi-direct product of the Cartan involution invariant subalgebra of [Formula: see text] and its vector representation. We show that the subalgebra that preserves the string charges, the string little algebra, is essentially the Borel subalgebra of [Formula: see text]. We also show that the known string physical states carry a representation of parts of this algebra.

Moving in on human motor cortex. Characterizing the relationship between body parts with non-rigid population response fields.

For cortical motor activity, the relationships between different body part representations is unknown. Through reciprocal body part relationships, functionality of cortical motor areas with respect to whole body motor control can be characterized. In the current study, we investigate the relationship between body part representations within individual neuronal populations in motor cortices, following a 7 Tesla fMRI 18-body-part motor experiment in combination with our newly developed non-rigid population Response Field (pRF) model and graph theory. The non-rigid pRF metrics reveal somatotopic structures in all included motor cortices covering frontal, parietal, medial and insular cortices and that neuronal populations in primary sensorimotor cortex respond to fewer body parts than secondary motor cortices. Reciprocal body part relationships are estimated in terms of uniqueness, clique-formation, and influence. We report unique response profiles for the knee, a clique of body parts surrounding the ring finger, and a central role for the shoulder and wrist. These results reveal associations among body parts from the perspective of the central nervous system, while being in agreement with intuitive notions of body part usage.

Features and Extra-Striate Body Area Representations of Diagnostic Body Parts in Anger and Fear Perception.

Social species perceive emotion via extracting diagnostic features of body movements. Although extensive studies have contributed to knowledge on how the entire body is used as context for decoding bodily expression, we know little about whether specific body parts (e.g., arms and legs) transmit enough information for body understanding. In this study, we performed behavioral experiments using the Bubbles paradigm on static body images to directly explore diagnostic body parts for categorizing angry, fearful and neutral expressions. Results showed that subjects recognized emotional bodies through diagnostic features from the torso with arms. We then conducted a follow-up functional magnetic resonance imaging (fMRI) experiment on body part images to examine whether diagnostic parts modulated body-related brain activity and corresponding neural representations. We found greater activations of the extra-striate body area (EBA) in response to both anger and fear than neutral for the torso and arms. Representational similarity analysis showed that neural patterns of the EBA distinguished different bodily expressions. Furthermore, the torso with arms and whole body had higher similarities in EBA representations relative to the legs and whole body, and to the head and whole body. Taken together, these results indicate that diagnostic body parts (i.e., torso with arms) can communicate bodily expression in a detectable manner.

Monotonicity of the principal pivot transform

We prove that the principal pivot transform (also known as the partial inverse, sweep operator, or exchange operator in various contexts) maps matrices with positive imaginary part to matrices with positive imaginary part. We show that the principal pivot transform is matrix monotone by establishing Hermitian square representations for the imaginary part and the derivative.

Real-time multitask multihuman–robot interaction based on context awareness

AbstractThis study presents a novel context awareness multihuman–robot interaction (MHRI) system that allows multiple operators to interact with a robot. In the system, a monocular multihuman 3D pose estimator is first developed with the convolutional neural network. The estimator first regresses a set of 2D joints representations of body parts and then restores the 3D joints positions based on these 2D representations. Further, the 3D joints are assigned to the corresponding individual with a priority–redundancy association algorithm. The whole 3D pose of each person is reconstructed in real time, even in crowded scenes containing both self-occlusion of the body and inter-person occlusion. Then, the identities of multiple persons are recognized with action context and 3D skeleton tracking to improve interactive efficiency. For context-awareness multitask interaction, the robot control strategy is designed based on target goal generation and correction. The generated goal is taken as a reference to the model predictive controller (MPC) to generate motion trajectory. Different interactive requirements are adapted by adjusting the weight parameters of the energy function of the MPC controller. Multihuman–robot interactive experiments, including dynamic obstacle avoidance (human–robot safety) and cooperative handling, demonstrate the feasibility and effectiveness of the MHRI, and the safety and collaborative efficiency of the system are evaluated with HRI metrics.

A collocation method to solve the parabolic-type partial integro-differential equations via Pell–Lucas polynomials

In this paper, a new collocation method based on the Pell–Lucas polynomials is presented to solve the parabolic-type partial Volterra integro-differential equations. According to the method, it is assumed that the solution of this equation is in the formu2N(x,t)≅∑n=0N∑s=0Nan,sQn,s(x,t),Qn,s(x,t)=Qn(x)Qs(t)which depends on the Pell–Lucas polynomials. Next, the matrix representation of the solution is written. Using this matrix form, the matrix representations of the partial derivatives, the matrix representations of the Volterra integral part and the matrix forms of the conditions are also constituted. All obtained matrix forms are substituted in the equation and its conditions. Using equally spaced collocation points in matrix forms of this equation and initial conditions, the equation is reduced to a system of algebraic equations. The solution of this system gives the coefficients of the assumed solution. Additionally, the error analysis for the method is presented. According to this, an upper bound of the errors is determined. Also, the error estimation is made with the help of the residual function. Moreover, the residual improvement technique is also applied. Then, all these procedures are then supported with the examples. The results obtained from these examples are clearly tabulated and graphed. An important aspect of this study is to compare the obtained results with the present method with other results in the literature.

Enhancing performance for three-phase induction motor by changing the magnetic flux density and core material using COMSOL

This paper presents a proposed design and analysis of a three-phase squirrel cage induction motor when changing of internal characteristic design for the three-phase induction motor. Two situations have been applied to enhancing the performance of the three-phase induction motor. The first situation has been implemented by changing the magnetic flux density (MFD) via the build of the six-phase for the same induction motor. The second situation has been implemented by changing core materials of the rotor part of the induction motor, like aluminum (AL) and cast iron (CI). The finite element method (FEM) has been used to analyze the rotor part, also to obtain the representation and simulation of the realty cylindrical rotor part of motor. The frequency domain (FD) analysis using to obtain the results within the environment of the COMSOL multiphysics 5.5 version.

Invited Session IV: Top-down vs. bottom-up approaches to computational modeling of vision: Limits of prediction accuracy on randomly selected natural images for model evaluation

Prediction accuracy on held-out data has become a critical analysis for quantitative model evaluation and hypothesis testing in computational cognitive neuroscience. In this talk, I will discuss the limits of prediction accuracy as a standalone metric, and highlight other considerations for model evaluation and interpretation. First, comparing two models on prediction accuracy alone does not reveal the degree to which the models have common underlying factors. I will advocate addressing this issue with variance partitioning, a form of commonality analysis, to reveal shared and unique variance explained by different models. Concretely, I will show how variance partitioning reveals representation of body parts and object boundaries in responses to multiple data sets of movie stimuli. Second, prediction accuracy is a metric for the variance explained by a given model. But for any experiment, the stimulus constrains the variance in the measured brain responses. Any given stimulus set runs the risk of excluding important sources of variation. A popular way to address this issue is to use photographs or movie clips as stimuli. Such naturalistic stimuli are typically sampled broadly from the world and thus have increased ecological validity, but random selection of natural stimuli often results in correlated features both within and between models. This often leads to ambiguous results, e.g. shared variance between models intended to capture different types of features. Furthermore, I will show that the same models (again of body parts and object boundaries) can yield quantitatively and in some cases qualitatively different results when applied to different data sets. This raises a critical question: if results for the same model vary across stimulus sets, which result provides a more solid basis for future work? Just as two clocks telling different times need a reference clock to be set, I will argue that we need broadly sampled sets of natural stimuli to use as a baseline for what, in various feature domains, constitutes "natural" variation and covariation. I will describe our collaboration to create just such a dataset of human visual experience, in the form of hundreds of hours of first-person video.

Dissemination, assessment and management of historic buildings by thematic virtual tours and 3D models

The digitalization of the historical-architectural heritage for virtual reality (VR) applications is crucial within the contemporary scientific and technical debate for several aspects. In fact, beyond the exploration for education and entertainment purposes, the employment of three-dimensional (3D) reality-based and computer-based models and environments seems to be very promising for performance assessment and risk management as well. Particularly, in order to develop and validate smart, low-cost and user-friendly tools, which might apply even in cases of limited time and budget, the present paper is going to propose a methodological workflow based on thematic virtual tours of 360° scenes, which integrate a variety of informative contents and digital products as external hotspots/switches. The VR tours, where 3D models might play a key role for an accurate representation of relevant parts and/or analytical elaboration of further data, are conceived as flexible and scalable solutions, supporting users, technicians and authorities through remote access, diagnosis of the state of conservation and communication of safety measures. The application of the proposed methods and techniques to a representative case study, the Norman-Swabian Castle of Gioia del Colle (Ba), South Italy, is presented in order to illustrate the achievable results and highlight the benefit of innovative “digital” solutions for data collection, storage and communication, compared to the traditional “analogical” practices. In detail, a Web-GIS platform, developed within a previous research project, is integrated with direct links to three thematic virtual tours that provide added contents for inclusive dissemination (timeline schemes, aerial views, 3D sculptural and architectural details), performance assessment (diagnostic reports, decay maps, 3D reconstructions of technical components) and risk management (exit signs, help instructions, warnings). Thus, the VR tours, while documenting realistically the state of the site, might act as host environments of digital products, at increasing complexity, all displayed according to an intuitive and accessible communication approach.Highlights:• Virtual tours of 360° scenes, linking thematic digital contents, are proposed as intuitive and versatile tools for smart documentation, conservation and protection of historical buildings.• The role of 3D reality-based and computer-based models is discussed toward their integration and correlation within thematic virtual tours of 360° scenes.• The potential of immersive environments for sharing knowledge about conservation issues and training users on safety measures in historic buildings is underlined.

Numbering The Ladies Waldegrave: Questions of Status and Display

At first glance, it appears as though Sir Joshua Reynolds’s The Ladies Waldegrave (1780) is in two places at once: Strawberry Hill House and the National Gallery, Edinburgh. Despite their visual indistinguishability, however, the former is a copy of the latter created by Factum Foundation in 2018. In this article, I discuss the ontological relation between paintings and their visually indistinguishable facsimiles, along with certain consequences that relation has for display practices. Traditionally, paintings are understood to be ontologically singular; no copy, however faithful, can ever stand in as the work itself. Using The Ladies Waldegrave, I defend ontological singularity while maintaining that these visually indistinguishable facsimiles can be used to promote engagement with, and a better understanding of, originals. Drawing on the philosophical idea that objects have temporal parts, I suggest that what I call suitable facsimiles – copies that are visually indistinguishable from originals – are representations of particular temporal parts of those originals. My proposal allows paintings to maintain their singularity while acknowledging that some copies share a special relationship with the originals such that the former can stand in for the latter. I conclude by considering issues concerning the display of both originals and suitable facsimiles.

Body Part-Level Domain Alignment for Domain-Adaptive Person Re-Identification With Transformer Framework

Although existing domain-adaptive person re-identification (re-ID) methods have achieved competitive performance, most of them highly rely on the reliability of pseudo-label prediction, which seriously limits their applicability as noisy labels cannot be avoided. This paper designs a Transformer framework based on body part-level domain alignment to solve the above-mentioned issues in domain-adaptive person re-ID. Different parts of the human body (such as head, torso, and legs) have different structures and shapes. Therefore, they usually exhibit different characteristics. The proposed method makes full use of the dissimilarity between different human body parts. Specifically, the local features from the same body part are aggregated by the Transformer to obtain the corresponding class token, which is used as the global representation of this body part. Additionally, a Transformer layer-embedded adversarial learning strategy is designed. This strategy can simultaneously achieve domain alignment and classification of the class token for each human body part in both target and source domains by an integrated discriminator, thereby realizing domain alignment at human body part level. Compared with existing domain-level and identity-level alignment methods, the proposed method has a stronger fine-grained domain alignment capability. Therefore, the information loss or distortion that may occur in the feature alignment process can be effectively alleviated. The proposed method does not need to predict pseudo labels of any target sample, so the negative impact caused by unreliable pseudo labels on re-ID performance can be effectively avoided. Compared with state-of-the-art methods, the proposed method achieves better performance on the datasets that are in line with real-world scene settings. The source codes of this paper will be available at https://github.com/lhf12278/BPDA.

Teaching Estimation and Control via Probabilistic Graphical Models – An Intuitive and Problem-Based Approach

This contribution discusses an approach to teaching estimation and control via probabilistic graphical models, more specifically via Forney-style factor graphs, combined with a problem-based learning exercise model. The course's overall rationale follows the idea that factor graphs present a unifying perspective on a vast range of topics in estimation and control and may thus present a substantially more intuitive access to the subject matter. Factor graphs allow for a rigorous approach to algorithm design via mixing and matching graphical representations of algorithms or parts thereof. Even though there is a substantial overhead in explaining and understanding the way algorithms can be presented on graphical models via message passing, we postulate that this additional effort pays off by highlighting similarities, enabling easier modifications, and presenting a seamless framework combining approaches from classical control and modern machine learning. Accordingly, the course is set up to combine two goals: It (i) presents canonical topics, such as advanced Kalman filtering, parameter estimation and control, while (ii) simultaneously preparing students to continue research in the domain of probabilistic inference. To promote the latter, the exercises associated with the course adopt a problem-based learning approach, asking students to utilize and possibly extend a toolbox for factor graphs when attempting to solve relevant and mostly application-driven challenges.

Научные поиски в советской кинематографии 1920-х–1930-х годов. (Метод «параллельной кинозасъемки» Анатолия Терского)

In this paper, we consider a unique period in the development of Soviet cinema, from 1928 to 1932, when the Geographical and Ethnographic Cinema-Atlas project was underway. It implied the making of a series of cultural films about the peoples and cultures of the USSR and, therefore, involved the search for scientific grounds for advancing cinematic art. In the second half of the 1920s, some Soviet filmmakers even worked out specific methods, based on real scientific research, which could be applied in the field of documentary. For example, one of the key trends in the theory and methodology of Soviet cinema in the 1920s–1930s was the study of the audience’s perception through decoding—with the help of psychology (reflexology)—of the recorded mimic reactions of viewers. We have analyzed the method of “parallel filming” of the audience, which was introduced by the Soviet film director and ethnographer Anatoly Terskoy within the scientific, cinematic, and ideological contexts. We believe that this overlooked concept is a valuable material for today’s documentary filmmakers. On the one hand, Terskoy’s works highlight the creative paradigms in which cinematographers were making their ethnographic and anti-religious films in the Soviet Union of the 1920s and 1930s. On the other hand, it was such scientific and creative searches that later became the theoretical basis for large-scale projects on the cinematic representation of different parts of the USSR on screen.

Generalized Auto‐Convolution Volterra Integral Equations: Numerical Treatments

In this paper, we use the operational Tau method based on orthogonal polynomials to achieve a numerical solution of generalized autoconvolution Volterra integral equations. Displaying a lower triangular matrix for basis functions, the corresponding solution is represented in matrix form, and an infinite upper triangular Toeplitz matrix is used to show the matrix representation of the integral part of the autoconvolution integral equation. We also investigate solvability of the obtained nonlinear system with infinite dimensional space and examine the convergence analysis of this method under the L2− norm. Finally, the efficiency of the operational Tau method is studied by numerical examples.

Linear programing formulation of a high temporal and technological resolution integrated energy system model for the energy transition

Models with a wide technological representation of energy systems can hardly adopt hourly resolutions to study the energy transition towards low-carbon technologies due to extended problem size. This compromises the model's ability to address the challenges of variable renewable energy sources and the cost-effectiveness of cross-sectoral flexibility options. This methodology presents a linear program model formulation that simultaneously adopts different temporal representations for different parts of the problem to overcome this issue. For instance, all electricity activities and their infrastructure representation require hourly constraints to better replicate system feasibility. The operation of gaseous networks is settled out with daily constraints. The balancing of the other activities of the system is represented with yearly constraints. Furthermore, the methodology adopts an hourly formulation to represent in detail 6 cross-sectoral flexibility archetypes: heat and power cogeneration, demand shedding, demand response, storage, smart charging and electric vehicles. The model can successfully solve the transition problem from 2020 to 2050 in 5-year intervals with more than 700 technologies and 140 activities (including the electricity dispatch of the Netherlands and 20 European nodes) in less than 6 hours with a normal computer.• Different temporal scales for the representation of different activities in the energy system.• A high-resolution hourly description for the formulation of cross-sectoral flexibility in integrated energy models.

Spatial probability maps of the segments of the postcentral sulcus in the human brain.

The postcentral sulcus is the posterior boundary of the postcentral gyrus where the somatosensory cortex is represented. In the human brain, the postcentral sulcus is composed of five distinct segments that are related to the somatosensory representation of different parts of the body. Segment 1 of the postcentral sulcus, located near the dorsomedial boundary of each hemisphere, is associated with toe/leg representations, segment 2 with arm/hand representations, segment 3 with blinking, and segments 4 and 5, which are near the lateral fissure and the parietal operculum, with the mouth and tongue representations. The variability in location and spatial extent of these five segments were quantified in 40 magnetic resonance imaging (MRI) anatomical brain scans registered to the stereotaxic space of the Montreal Neurological Institute (MNI space), in the form of volumetric (using MINC Toolkit) and surface (using FreeSurfer) spatial probability maps. These probability maps can be used by researchers and clinicians to improve the localization of the segments of the postcentral sulcus in MRI images of interest and also to improve the interpretation of the location of activation peaks generated in functional neuroimaging studies investigating somatosensory cortex.

Spatial tuning of face part representations within face-selective areas revealed by high-field fMRI.

Regions sensitive to specific object categories as well as organized spatial patterns sensitive to different features have been found across the whole ventral temporal cortex (VTC). However, it is unclear that within each object category region, how specific feature representations are organized to support object identification. Would object features, such as object parts, be represented in fine-scale spatial tuning within object category-specific regions? Here, we used high-field 7T fMRI to examine the spatial tuning to different face parts within each face-selective region. Our results show consistent spatial tuning of face parts across individuals that within right posterior fusiform face area (pFFA) and right occipital face area (OFA), the posterior portion of each region was biased to eyes, while the anterior portion was biased to mouth and chin stimuli. Our results demonstrate that within the occipital and fusiform face processing regions, there exist systematic spatial tuning to different face parts that support further computation combining them.

Early Pleistocene hominin subsistence behaviors in South Africa: Evidence from the hominin-bearing deposit of Cooper's D (Bloubank Valley, South Africa)

Evidence of the consumption of meat through hunting or scavenging by Early Pleistocene hominins is scarce, particularly in South Africa. Moreover, the interpretations of taphonomic evidence are subject to an important discussion commonly called the ‘hunting-vs-scavenging debate.’ Until today, only the Swartkrans Members 1–3 site has yielded a butchered bone assemblage large enough to permit reconstruction of carcass acquisition strategies by Early Pleistocene hominins in South Africa. This leaves an information gap between 1.4 and 1.0 Ma. Here, we provide the first evidence of meat consumption by hominins during this gap, based on the zooarchaeological study of the large mammal bone assemblage recovered from the Cooper's D site, South Africa. Based on skeletal part representation, our results show density-mediated attrition of bovid bones due to predepositional and postdepositional destruction. We argue that this attrition is the result of both abiotic (i.e., decalcification) and biotic (i.e., carnivore ravaging) processes. Bovid mortality profiles point out the involvement of ambush predators such as large felids. Bone surface modifications also indicate that the assemblage has been accumulated mostly by carnivores but with some hominin involvement as well. We observe all the stages of animal carcass processing (skinning, disarticulation, defleshing, marrow extraction) as well as the exploitation of a diversity of prey size classes at both Swartkrans Members 1–3 and Cooper's D. Thus, our study shows the importance of the Cooper's D bone assemblage for understanding Early Pleistocene hominin subsistence behaviors. Moreover, this article highlights the need for including long bone flake specimens in the analysis of large bone assemblages from South African caves to better understand the Early Pleistocene hominin bone damage record.

Reconstructing the sequence of an Inca Period (1470-1532 CE) camelid sacrifice at El Pacífico, Peru

Animal sacrifice has played an important role as a material expression of the ritual behavior practiced by different societies around the world. In the South American Andes, the ceremonial immolation of llamas is well documented by both ethnohistoric and ethnographic sources. Nevertheless, archaeological evidence of animal sacrifice remains poorly documented. In this paper, we report the burial of two young camelids from El Pacífico, a Formative Period ceremonial site located on the central coast of Peru. AMS radiocarbon dates suggest the ritual sacrifice occurred when the architecture of the site was no longer in use, around the time of the Inca conquest. Based on the presence of cut marks and fly pupae, we suggest that one of the camelids, a yearling llama, was sacrificed by removal of its heart and buried shortly thereafter. Similarly, given the location of cut marks and representation of skeletal parts, we infer that the second camelid was slaughtered for human consumption prior to burial. In accordance with documented Andean rites, archaeological evidence from El Pacifico suggests that practitioners of camelid sacrifice followed a behavioral script following the selection of the animal to its final interment. We hypothesize the costly performance of this ceremony at an ancestral sacred site was part of a social and political strategy for promoting intergroup social cohesion during the arrival of the Incas to the region.