Relative Body Orientation Research Articles

A non‐verbal teaching behaviour analysis for improving pointing out gestures: The case of asynchronous video lecture analysis using deep learning

AbstractBackgroundResearch into enhancing the effectiveness of information delivery in asynchronous video lectures remains sparse. This study analyzes the nonverbal teaching behaviours in asynchronous online videos, drawing comparisons between pre‐service and in‐service teachers (ITs).ObjectivesThis research primarily aims to juxtapose the nonverbal teaching behaviours, such as arm extensions and body orientation, utilized by pre‐service teachers (PTs) and ITs within asynchronous online videos.MethodsAsynchronous video lectures from four pre‐service and four ITs across four diverse subject topics were scrutinized. Leveraging deep learning technology, teachers' poses during their instruction towards a video camera were quantified, with a particular focus on arm stretch range and body orientation in relation to the subject being taught.ResultsThe findings revealed that PTs were deficient in effectively employing pointing gestures. Their arm stretches and body orientation towards the board were not differentiated across subjects. Conversely, ITs demonstrated subject‐specific variations in their arm extension and body orientation, signalling their effective strategies for knowledge dissemination.Conclusions and DiscussionThis study emphasizes the importance of assessing nonverbal teaching behaviours in the development of effective instructional training. It accentuates the need for nonverbal communication and subject‐specific teaching strategy training in PTs. Future investigations could broaden their scope to include larger sample sizes and expanded subject areas to discern more comprehensive trends in nonverbal teaching behaviours.

Grooming site preferences in black capuchin monkeys: Hygienic vs. social functions revisited.

When primates groom each other, they tend to concentrate on those parts of the body they cannot efficiently self-groom (i.e., not visually accessible), and prefer to intensify grooming in areas with high hair density, thus suggesting a hygienic function. However, preferences for some body sites over others during social grooming may also result from different degrees of social bonding and relative dominance. To assess the relative importance of physical (hygienic) and social factors, we examined grooming interactions in two groups of wild black capuchin monkeys (Sapajus nigritus) during 15 nonconsecutive months. We evaluated the distribution of social grooming across body sites according to their accessibility by self-grooming and hair density. At the same time, we assessed whether the degree of dyadic social bonding affects the relative body orientation between groomer and groomee and the access to vulnerable body sites (e.g., face, throat, groin) during grooming. As expected, capuchins preferentially groomed inaccessible body sites (e.g., back and head), with a disproportionate effort directed to the tufts of their partners. We found that dyadic social bond strength, together with rank distance, significantly affected the proportion of grooming in ventro-ventral body relative orientation only in dominant-subordinate groomer-groomee dyads. This may indicate that, when two individuals differ in rank but are strongly bonded, the level of uncertainty related to the social context is already resolved and thus grooming per se is no longer perceived by the subordinate as an uncertain/risky situation. We found no effect of social bonding on grooming vulnerable body sites for any type of dyad. Our findings suggest that grooming site preferences in black capuchin monkeys simultaneously reflect hygienic and social functions.

SMAC

Prior research has demonstrated that users are increasingly employing multiple devices during daily work. Currently, devices such as keyboards, cell phones, and tablets remain largely unaware of their role within a user's workflow. As a result, transitioning between devices is tedious, often to the degree that users are discouraged from taking full advantage of the devices they have within reach. This work explores the device ecologies used in desk-centric environments and complies the insights observed into SMAC, a simplified model of attention and capture that emphasizes the role of user-device proxemics, as mediated by hand placement, gaze, and relative body orientation, as well as inter-device proxemics. SMAC illustrates the potential of harnessing the rich, proxemic diversity that exists between users and their device ecologies, while also helping to organize and synthesize the growing body of literature on distributed user interfaces. An evaluation study using SMAC demonstrated that users could easily understand the tenants of user- and inter-device proxemics and found them to be valuable within their workflows.

Measuring Interaction Proxemics with Wearable Light Tags

The proxemics of social interactions (e.g., body distance, relative orientation) influences many aspects of our everyday life: from patients' reactions to interaction with physicians, successes in job interviews, to effective teamwork. Traditionally, interaction proxemics has been studied via questionnaires and participant observations, imposing high burden on users, low scalability and precision, and often biases. In this paper we present Protractor, a novel wearable technology for measuring interaction proxemics as part of non-verbal behavior cues with fine granularity. Protractor employs near-infrared light to monitor both the distance and relative body orientation of interacting users. We leverage the characteristics of near-infrared light (i.e., line-of-sight propagation) to accurately and reliably identify interactions; a pair of collocated photodiodes aid the inference of relative interaction angle and distance. We achieve robustness against temporary blockage of the light channel (e.g., by the user's hand or clothes) by designing sensor fusion algorithms that exploit inertial sensors to obviate the absence of light tracking results. We fabricated Protractor tags and conducted real-world experiments. Results show its accuracy in tracking body distances and relative angles. The framework achieves less than 6° error 95% of the time for measuring relative body orientation and 2.3-cm - 4.9-cm mean error in estimating interaction distance. We deployed Protractor tags to track user's non-verbal behaviors when conducting collaborative group tasks. Results with 64 participants show that distance and angle data from Protractor tags can help assess individual's task role with 84.9% accuracy, and identify task timeline with 93.2% accuracy.

An Experimental Investigation into the Impact of Vehicular Traffic on Interpersonal Wearable-to-Wearable Communications Channels

In this paper, we have investigated the effects of vehicular traffic on interpersonal wearable-to-wearable (W2W) communications channels in an urban environment at 2.45 GHz. In particular, we have studied the perturbations in the received signal caused by different types of vehicles as they passed through a channel between two persons who maintained various relative orientations while positioned at the opposite sides of a road. As the channel underwent different fading mechanisms depending on whether the vehicle was approaching, transitioning (i.e., intersecting the direct signal path), or receding from the persons, the overall disturbance was appropriately segmented depending on the journey stage. The results have shown that relative body orientation was a significant factor when considering the impact that a vehicle can have on a W2W link. When both persons faced the oncoming traffic, the link was particularly susceptible to significant fading events with variations in the received signal power from the unperturbed state as great as 44.1 dB observed to occur. For all of the journey stages, irrespective of the relative orientation of the persons, the logarithmically transformed long-term fading process was found to be multimodal and well described by a Gaussian mixture model. During the transitioning phase, shadowing caused by the passing automobile obstructing the line-of-sight signal path was found to be the main contributor to the signal fading. However, probably the most remarkable result of the channel characterization work conducted in this paper was the severity of the short-term fading often observed. Such was the intensity of the measured envelope fluctuation in many of the scenarios, we have been able to utilize the recently proposed $\kappa -\mu $ extreme distribution with great success and in the process, provide a further important empirical validation of this new fading model. Moreover, we have used the resistor-average distance, which is derived from the Kullback–Leibler distance to show the improved fit that the $\kappa -\mu $ extreme distribution offers compared with the $\kappa -\mu $ distribution when used to model the W2W channel in this fading environment.

Pitfalls Encountered during Documentation of Cases of Fatal Fall from Height Presented to Kafr EL Sheikh-Medico legal Department during the Period from (1999 to 2013)

Fall from height represents an important form of blunt trauma in society. The incidence of deaths due to fall from height is increasing day by day. So, determination of the manner of fatal fall from a height is very important issue. When establishing the mode of death, it is essential for the forensic pathologist to reconsider autopsy findings, outcome of toxicology screening, and circumstances at the death scene. The present study aimed first, at throwing light on the pitfalls encountered during examination of medico legal (ML) reports of cases of falling from height. Second, design a ML protocol for documentation of deaths due to falling from height. The current study was a retrospective study of the records of cases of fatal fall from height presented to Kafr EL Sheikh-Medico legal Department during the period from 1st of January 1999 till the 31st of December 2013. The records were examined for: personal data, detailed history of the cases, scene examination, autopsy findings and Toxicological screening. The results of the present study showed that the total number of the reported cases was 21 cases. The age of the victims ranged from 8 to 69 years, males presented (61.9%) of cases. Data about employment was documented in only (38.1%) of cases. Data about the circumstantial events were missing in most of the records. Accidental falls were the most prevalent manner. Suicidal falls were the second prevalent manner .Scene examination revealed that falls of (71.44%) of cases was from buildings. The height of fall was found in majority of records to be from the 4th storey. Examination of the path of fall was not reported in most of cases (95.23%). The nature of impact surface was documented only in (38.1%) of cases. Body orientation in relation to impact surface was mentioned in (38.1%) of cases. Records describing the site of fall from inside were very defective. The presence of barrier and its height was reported in (33.33%) of cases. Whole body radiography and external body measurements were not performed in any of the studied cases. Autopsy findings showed that the head and the thorax were the most affected regions. The probable primary site of impact was concluded by autopsy in (47.62%) of cases. The cause of death was head injuries in the majority of cases either by itself or in conjunction with other injuries. Toxicological screening of the commonly used drugs was carried in (90.48%) of the cases, where it was negative in (85.72%) of cases. Blood alcohol content was performed in (61.9%) of the cases and it was negative. The study concluded deficient documentation of data about the history of the cases; scene examination, autopsy findings and toxicological screening. Many recommendations were suggested and a protocol for documentation of the cases of fatal fall from height was proposed.

Foreword: Mobility and Social Networks Confluence

Mobile devices, wearables and wireless sensor networks have been lately used tomonitor and sense real world. On one hand, processing of information that has been sensed in the real world has been used for a wide set of applications. These applications include detection of human activities, environmental and urban state monitoring, estimation of healthcare conditions, proximity and concentrations of people, epidemic trends, network and routing planning and other natural and human-generated situations describing aspects of the physical world. On the other hand, the evolution of the web in terms of user-generated content, crowd sourcing and the proliferation of online social networks have generated tremendous amount of information, describing dynamic interaction among people and their surroundings in both, digital (online) and real worlds, making people-generated information to become a new type of virtual sensor. In this respect, the amount of information available from the connected world, either belonging to virtual or to physical sources, can describe aspects of reality in a detailed manner if both sources are combined. The kind of dynamics that the integration of digital and physical worlds may generate will have an impact at different levels, involving the humansocial-environmental dimensions as well as at the network organization. In this regard, a set of novel research challenges will arise for dealing with such integration of information. This Special Issue was planned to report advances on applications, methods and approaches envisioning to address the new challenges in this field. The selected papers are roughly summarized as below: The following four papers would contribute to application aspects in the mobile and social networks confluence. The paper titled “Information Propagation through Opportunistic Communication in Mobile Social Networks” presents a theoretical framework to evaluate the performance of information propagation mobile social networks formed by short range communication technologies. The paper titled “Social and Content Hybrid Image Recommender System for Mobile Social Networks” proposes a hybrid image recommender system, which combines collaborative filtering (social techniques) with content-based techniques. The paper titled “Selective Data Deactivation Mechanism in Sustainable Area-based Cache for Mobile Social Networks” presents a resilient mechanism for the proposed area-based distributed mobile cache system under a temporary decrease of the number of terminals. The paper titled “Trigger detection using geographical relation graph for social context awareness” discusses a trigger detection mechanism based on a mixed graph-based representation model able to encode geographical and social relationships among people and social objects like stores, restaurants, and event spots. The rest of the selected papers are efforts on more fundamental issues, i.e., measurement and analysis in the mobile and social networks confluence. The paper titled “Analysis of Social Interactions through Mobile Phones” discusses the feasibility of using two parameters that can be detected through mobile phone sensing, namely interpersonal distance and relative body orientation, to provide a solid basis for inferring social interactions. The paper titled “ Urban 802.11 Community Networks for Mobile Users: Current Deployments and Prospective” analyzes the deployment and the performance of wireless networks in an urban environin order to measure the potential of currently available networks for providing Internet connectivity for mobile users. We sincerely appreciate the contributions of all the authors who made submissions to this special issue. We should also mention this special issue would not have been possible without the contributions of the numerous reviewers who O. Mayora Ibarra (*) Center for Research and Telecommunication Experimentation for Networked Communities, CREATE-NET, Via alla Cascata 56/D, Povo, 38123 Trento, Italy e-mail: oscar.mayora@create-net.org

Analysis of Social Interactions Through Mobile Phones

Equipment of mobile phones with various kinds of sensors is transforming these devices from mere capabilities of voice and internet access to devices capable of sensing a number of phenomena pertaining to their users. In this paper we make use of these capabilities of phones to detect social interactions between people and analyze social context by using embedded sensors found in typical smart phones. Work carried out in this area has typically used dedicated hardware to establish social interactions, and we contend on the suitability of mobile phone, since additional devices that user is not familiar with influence natural user behavior and thus their social interaction patterns. Our work shows that two parameters that can be detected through mobile phone sensing, namely interpersonal distance and relative body orientation, provide a solid basis for inferring social interactions. We describe how these factors are acquired using smart phones and describe our analysis. The experiments demonstrate that we can recognize not only whether a social interaction is taking place, but also the type of social interaction, distinguishing between formal and informal social settings.

Deducing evidence for social situations from dynamic geometric interaction data

We discuss how time-independent and time-dependent features of human social interaction geometry on small temporal and spatial scales may be used to extract evidence for or against the existence of social situations as a simple form of social context. Aside from providing a new method for quantitative investigation of human interaction behaviour, the ultimate vision motivating this research focuses on mobile devices autonomously measuring and processing data on interaction geometries in order to derive social situation context that can be used in mobile social networking scenarios. Our method is tested via an experiment using an IR tracking method already allowing for the precise determination of interpersonal distances and relative body orientation in a conversational setting. We investigate the performance of time-independent classifiers for the prediction of the involvement of pairs of persons in a social situation using relative distance and orientation. We then discuss results of using HMMs for exploiting the time-dependency of the interaction geometry.

Synchronous Gestures in Multi-Display Environments

ABSTRACT Synchronous gestures are patterns of sensed user or users' activity, spanning a distributed system that take on a new meaning when they occur together in time. Synchronous gestures draw inspiration from real-world social rituals such as toasting by tapping two drinking glasses together. In this article, we explore several interactions based on synchronous gestures, including bumping devices together, drawing corresponding pen gestures on touch-sensitive displays, simultaneously pressing a button on multiple smart-phones, or placing one or more devices on the sensing surface of a tabletop computer. These interactions focus on wireless composition of physically colocated devices, where users perceive one another and coordinate their actions through social protocol. We demonstrate how synchronous gestures may be phrased together with surrounding interactions. Such connection-action phrases afford a rich syntax of cross-device commands, operands, and one-to-one or one-to-many associations with a flexible physical arrangement of devices. Synchronous gestures enable colocated users to combine multiple devices into a heterogeneous display environment, where the users may establish a transient network connection with other select colocated users to facilitate the pooling of input capabilities, display resources, and the digital contents of each device. For example, participants at a meeting may bring mobile devices including tablet computers, PDAs, and smart-phones, and the meeting room infrastructure may include fixed interactive displays, such as a tabletop computer. Our techniques facilitate creation of an ad hoc display environment for tasks such as viewing a large document across multiple devices, presenting information to another user, or offering files to others. The interactions necessary to establish such ad hoc display environments must be rapid and minimally demanding of attention: during face-to-face communication, a pause of even 5 sec is socially awkward and disrupts collaboration. Current devices may associate using a direct transport such as Infrared Data Association ports, or the emerging Near Field Communication standard. However, such transports can only support one-to-one associations between devices and require close physical proximity as well as a specific relative orientation to connect the devices (e.g., the devices may be linked when touching head-to-head but not side-to-side). By contrast, sociology research in proxemics (the study of how people use the “personal space” surrounding their bodies) demonstrates that people carefully select physical distance as well as relative body orientation to suit the task, mood, and social relationship with other persons. Wireless networking can free device-to-device connections from the limitations of direct transports but results in a potentially large number of candidate devices. Synchronous gestures address these problems by allowing users to express naturally a spontaneous wireless connection between specific proximal (collocated) interactive displays.

Role of lateral muscles and body orientation in feedforward postural control

The study investigates the role of lateral muscles and body orientation in anticipatory postural adjustments (APAs). Subjects stood in front of an aluminum pendulum and were required to stop it with their right or left hand. An experimenter released the pendulum inducing similar body perturbations in all experimental series. The perturbation directions were manipulated by having the subjects standing on the force platform with different body orientations in relation to the pendulum movements. Consequently, perturbations were induced in sagittal, oblique, and frontal planes. Ground reaction forces and bilateral EMG activity of dorsal, ventral, and lateral trunk and leg muscles were recorded and quantified within the time intervals typical of APAs. Anticipatory postural adjustments were seen in all experimental conditions; their magnitudes depended on the body orientation in relation to the direction of perturbation. When the perturbation was produced in the lateral and oblique planes, APAs in the gluteus medius muscles were greater on the side opposite to the side of perturbation. Conversely, simultaneous anticipatory activation of the external obliques, rectus abdominis, and erector spinae muscles was observed on the side of perturbation when it was induced in the lateral plane. The results of the present study provide additional information on the directional specificity of anticipatory activation of ventral and dorsal muscles. The findings provide new data on the role of lateral muscles in feedforward postural control and stress the importance of taking into consideration their role in the control of upright posture.

The neural representation of postural control in humans.

Lesion of the "vestibular cortex" in the human posterior insula leads to a tilted perception of visual vertical but not to tilted body posture and loss of lateral balance. However, some stroke patients show the reverse pattern. Although their processing of visual and vestibular inputs for orientation perception of the visual world is undisturbed, they push away actively from the ipsilesional side (the side of lesion location), leading to a contraversive tilt of the body (tilt toward the side opposite to the lesion) and falling to that side. Recently, the origin of contraversive pushing was identified as an altered perception of the body's orientation in relation to gravity. These patients experience their body as oriented "upright" when actually tilted enormously to the ipsilesional side (18 degrees on average). The findings argued for a separate pathway in humans for sensing body orientation in relation to gravity apart from the one projecting to the vestibular cortex. The present study aimed at identifying this brain area. The infarcted brain regions of 23 consecutively admitted patients with severe contraversive pushing were projected onto a template MRI scan, which had been normalized to Talairach space. The overlapping area of these infarctions centered on the posterolateral thalamus. Our finding necessitates reinterpretation of this area as being only a "relay structure" of the vestibular pathway on its way from the brainstem to the vestibular cortex. The ventral posterior and lateral posterior nuclei of the posterolateral thalamus (and probably its cortical projections) rather seem to be fundamentally involved in the neural representation of a second graviceptive system in humans decisive for our control of upright body posture.

AGONISM IN ASTEROIDS.

1. Intraspecific agonistic behavior, called bouts, which involves ray interactions between individual sea stars, is reported in species from all three living orders of asteroids and described for Patiria miniata and Pycnopodia helianthoides. This behavior indicates a certain sensitivity to conspecific contact on the aboral surface, in which each individual attempts to place a ray or rays on top of its opponent, an act which may initiate opponent withdrawal. Agonistic intraspecific bouts affect the distribution and feeding of both species although bouts may take place where food is not present. 2. Patiria bouts may last over two hours and sometimes terminate by individuals overlapping and sharing food. Evidence suggests that Patiria bouts are: (a) quite common; (b) not related to sexual behavior; (c) territorial; and (d) influenced as to outcome by relative body orientation; however, when territorial behavior is involved, relative body orientation does not affect bout outcomes. Pycnopodia bouts are of shorter duration (up to 10 minutes), terminating with the withdrawal of one or both animals, and sometimes resulting in an extensive pursuit. 3. Two forms of intraspecific Patiria bouts are noted: continuous-contact and intermittent-contact. Intermittent-contact bouts appear less intensive, permitting individuals to feed and to engage in bouts with more than one opponent at a time. It is speculated that intermittent-contact bouts are a type of ritualized activity of a fairly complex nature. 4. Interspecific bouts between specimens of Pycnopodia and two species of Pisaster (P. giganteus and P. brevispinus) have been observed only when the Pisaster sp. is in possession of food. Pycnopodia individuals approach and place rays on the aboral surface of the feeding sea star while attempting to obtain the food with other rays. The specimen of Pisaster sp. actively counterattacks using its pedicellariae.