Crowded Space Research Articles

Acute unilateral vestibular neuritis contributes to alterations in vestibular function modulating circumvention around obstacles: A pilot study suggesting a role for vestibular signals in the spatial perception of orientation during circumvention.

Walking among crowds avoiding colliding with people is described by patients with vestibular disorders as vertigo-inducing. Accurate body motion while circumventing an impeding obstacle in the gait pathway is dependent on an integration of multimodal sensory cues. However, a direct role of vestibular signals in spatial perception of distance or orientation during obstacle circumvention has not been investigated to date. We examined trunk yaw motion during circumvention in patients with acute unilateral vestibular loss (aUVL) and compared their results with age-matched healthy controls (HCs). Subjects performed five gait tasks with eyes open two times: walk 6 m in total, but after 3 m, circumvent to the left or right, as closely as possible, a cylindrical obstacle representing a person, and then veer back to the original path; walk 6 m, but after left and right circumvention at 3 m, veer, respectively, to the right, and left 45 deg; and walk 6 m without circumvention. Trunk yaw angular velocities (YAVs) were measured using a gyroscope system. Yaw angular velocity peak amplitudes approaching to, and departing from, the circumvented object were always greater for patients with aUVL compared to HCs, regardless of whether passing was to the aUVLs' deficit or normal side. The departing peak YAV was always greater, circa 52 and 87%, than the approaching YAV for HCs when going straight and veering 45 deg (p ≤ 0.0006), respectively. For patients with aUVL, departing velocities were marginally greater (12%) than approaching YAVs when going straight (p < 0.05) and were only 40% greater when veering 45 deg (p = 0.05). The differences in departing YAVs resulted in significantly lower trajectory-end yaw angles for veering trials to the deficit side in patients with aUVL (34 vs. 43 degs in HCs). The results demonstrate the effects of vestibular loss on yaw velocity control during the three phases of circumvention. First, approaching an obstacle, a greater YAV is found in patients with aUVL. Second, the departing YAV is found to be less than in HCs with respect to the approaching velocity, resulting in larger deficit side passing yaw angles. Third, patients with UVLs show yaw errors returning to the desired trajectory. These results could provide a basis for rehabilitation protocols helping to avoid collisions while walking in crowded spaces.

Large strongly anti-Urysohn spaces exist

As defined in [3], a Hausdorff space is strongly anti-Urysohn (in short: SAU) if it has at least two non-isolated points and any two infinite closed subsets of it intersect. Our main result answers the two main questions of [3] by providing a ZFC construction of a locally countable SAU space of cardinality 2c. The construction hinges on the existence of 2c weak P-points in ω⁎, a very deep result of Ken Kunen.It remains open if SAU spaces of cardinality >2c could exist, while it was shown in [3] that 22c is an upper bound. Also, we do not know if crowded SAU spaces, i.e. ones without any isolated points, exist in ZFC but we obtained the following consistency results concerning such spaces.(1)It is consistent that c is as large as you wish and there is a locally countable and crowded SAU space of cardinality c+.(2)It is consistent that both c and 2c are as large as you wish and there is a crowded SAU space of cardinality 2c.(3)For any uncountable cardinal κ the following statements are equivalent:(i)κ=cof([κ]ω,⊆).(ii)There is a locally countable and crowded SAU space of size κ in the generic extension obtained by adding κ Cohen reals.(iii)There is a locally countable and countably compact T1-space of size κ in some CCC generic extension.

Pazarların Çevresel Mekân Tasarım Ölçütleri Bağlamında Kadıköy Salı Pazarının Değerlendirilmesi

Kentlerin evrimi, kentsel ve kırsal ekonomileri birbirine bağlayan ticarete dayanmaktadır. Çeşitli arkeolojik kalıntılara göre ticari etkinliklerin 10.000 yıldan daha fazla bir geçmişe sahip olduğu düşünülmektedir. Pazarlar ilkçağlardan bu yana insanların gereksinimlerini temin etmede önemli bir yere sahiptir. Dünya’da var olan eski şehirler surlarla çevrilmiş pazarlardan oluşurdu. Bu kent merkezlerinde temel işlev olan ticaret yüzyıllardır değişmeden kalmıştır. Pazarlar yol üstünde, kutsal dini yerlere yakın, önemli geçiş mekanlarında, limanlarda ve kabilelerin istedikleri mekanlar üzerinde kurulmaktaydı. Pazarların ortaya çıkması, ürün değişimini ve ticareti kolaylaştırmış, topluluklar arasında daha rahat ve kolay etkileşime girme olanağı sunmuş, müşteriler ve satıcılar arasındaki prosedürleri ve aracıları ortadan kaldırarak işlem sayısını azaltmıştır. Halka açık pazarlar, kullanıcılar için her zaman tercih sebebi olmuştur. Günümüzde kamusal alanlar üzerinde açık veya kapalı pazar yerleri kurulmaktadır. Pazarcılar, belediyenin kontrolü altında getirdiği kurallar çerçevesinde olsa bile olumsuz mekân ve iklim koşullarında çalışmaktadır. Bu nedenle, kullanıcı olarak pazarcı ve alışveriş yapanlar için pazar yerlerinin tasarımında çevresel mekân tasarım ölçütleri dikkate alınmalıdır. Bu çalışmada semt pazarlarında belediye kontrolü altında gösterilen planlı kamusal alanlarda var olduğu örnekleminden yola çıkarak, Kadıköy Salı pazarının ilk halinden bu yana konumu ve çevresel mekân tasarım ölçütleri araştırılmış ve son yapılan Salı pazar yerinin kamu mekânı olarak kullanıcıları açısından bu ölçütler yerinde yapılan tespitlerle değerlendirilmiştir.

Monitoring Social Distancing in Queues Using Infrared Array Sensor

Since the emergence of the coronavirus disease (COVID-19), more than 165 million people have been infected all around the world (as of May 2021). The COVID-19 virus is highly contagious, especially in large crowded spaces. To prevent the infection and slow the transmission of the virus, the World Health Organization recommends wearing a mask, washing hands regularly, and maintaining a distance of at least one meter between people. To support this prevention, we propose a connected object based on LoRa technology to monitor the social distancing of one meter between people in queues. The proposed system uses infrared array sensor MLX60940 to detect people through their body temperature. Based on this output, we developed an algorithm to verify social distancing. The main advantage of this node is its ability to preserve the privacy of detected people and consume less energy compared to camera-based systems. Experimental results show that the proposed node can detect up to six persons per queue with an accuracy of 93% when the distance between people is below 80 cm.

A Study on the Scenario of Evacuation Safety Analysis of Wide-Area Railroad Stations

There are 1,416 railway stations in this country, of which 729 are underground stations. Moreover, more than 50% of the stations are constructed underground. Recently, the deep depth wide-area railroad has being designed and constructed. Railroads are the main means of transportation for the people and confirming evacuation safety in crowded underground spaces is a crucial subject. The functions of urban railroads and wide-area railroad underground stations built in urban underground spaces are the same. Nevertheless, there are differences between the station safety analysis scenario and the method used when they were designed. Through the analysis of evacuation scenarios and methods applied when evaluating the safety of underground stations, we propose procedures and standards for analyzing the safety of underground stations that can be applied to two types of railroads; the urban and wide-area railroads.

Phase Separation-Mediated Chromatin Organization and Dynamics: From Imaging-Based Quantitative Characterizations to Functional Implications.

As an effective and versatile strategy to compartmentalize cellular components without the need for lipid membranes, phase separation has been found to underpin a wide range of intranuclear processes, particularly those involving chromatin. Many of the unique physico-chemical properties of chromatin-based phase condensates are harnessed by the cell to accomplish complex regulatory functions in a spatially and temporally controlled manner. Here, we survey key recent findings on the mechanistic roles of phase separation in regulating the organization and dynamics of chromatin-based molecular processes across length scales, packing states and intranuclear functions, with a particular emphasis on quantitative characterizations of these condensates enabled by advanced imaging-based approaches. By illuminating the complex interplay between chromatin and various chromatin-interacting molecular species mediated by phase separation, this review sheds light on an emerging multi-scale, multi-modal and multi-faceted landscape that hierarchically regulates the genome within the highly crowded and dynamic nuclear space. Moreover, deficiencies in existing studies also highlight the need for mechanism-specific criteria and multi-parametric approaches for the characterization of chromatin-based phase separation using complementary techniques and call for greater efforts to correlate the quantitative features of these condensates with their functional consequences in close-to-native cellular contexts.

Using Mahalanobis Distances to Investigate Second Dialect Acquisition: A Study on Quebec French.

Second dialect acquisition (SDA) can be defined as the process through which geographically mobile individuals adapt to new dialect features of their first language. Two common methodological approaches in SDA studies could lead to underestimating the phonetic changes that mobile speakers may experience: only large phonetic differences between dialects are considered, and external sources are used to infer what should have been the speakers' original dialect. By contrast, in this study, we carry out a longitudinal analysis to empirically assess the speakers' baseline and shift away from it with no priors as to which features should change or not. Furthermore, we focus on Quebec French, a variety with a relatively crowded vowel space. Using Mahalanobis distances, we measure how acoustic characteristics of vowels produced by 15 mobile speakers change relative to those of a control group of 8 sedentary speakers, with the mobile participants recorded right after they moved to Quebec City, then a year later. Overall, the results show a reduction of Mahalanobis distances over time, indicating convergence toward the control system. Convergence also tends to be greater in denser areas of the vowel space. These results suggest that phonetic changes during SDA could be finer than previously thought. This study calls for the use of methodological approaches that can reveal such trends, and contributes to uncovering the extent of phonetic flexibility during adulthood.

Vision-based estimation of the number of occupants using video cameras

Although occupancy information is critical to energy consumption of existing buildings, it still remains to be a major source of uncertainty. For reliable and accurate occupant modeling with minimal uncertainties, capturing precise occupant information on occupants is essential. This paper proposes a computer vision-based approach that utilizes deep learning architectures to estimate of the number of people in large, crowded spaces using multiple cameras. Various vision techniques (head detection, background elimination, head tracking) are implemented in three methods: (i) a method that instantaneously counts people in a scene, (ii) a method that incrementally counts people entering/exiting a room and (iii) a combination of the first two methods. These methods were applied in a classroom with heavy occlusions, and resulted in a high prediction capacity when compared to ground truth measurements. Future work in video-analytical approaches can address problems regarding lowering the computational cost of analysis, capturing occupancy data in complex room geometries and addressing concerns in privacy preservation.

Detection of SARS-CoV-2 in the Indoor and Outdoor Areas of Urban Public Transport Systems of Three Major Cities of Portugal in 2021.

Airborne transmission is mainly associated with poorly ventilated and crowded indoor environments where people stay for long periods of time. As such, public transport is often perceived as having a high risk for the transmission of SARS-CoV-2. Considering that data on the detection of SARS-CoV-2 in public transport systems are scarce, we performed air sampling for SARS-CoV-2 in indoor and outdoor spaces of public transport systems in Portugal. Air (n = 31) and surface (n = 70) samples were collected using a Coriolis® Compact microbial air sampler and sterile flocked plastic swabs, respectively. Samples were extracted and analyzed through RT-qPCR. Only two air samples from an outdoor and a partially open space were found to be positive for SARS-CoV-2 RNA. No positive surface samples were detected. These results indicate that the viral concentration in ambient air in public transport systems is linked to the number of people present in that environment and whether they are wearing properly fitting masks. Considering the current lifting of COVID-19 restrictions around the world, it is essential that people continue to wear masks in both indoor and outdoor environments, especially in crowded spaces. More studies on this topic are needed to fully elucidate the real risk of infection in outdoor spaces.

Riding the wave: Predicting the use of the bike-sharing system in Barcelona before and during COVID-19.

To simultaneously promote health, economic, and environmental sustainability, a number of cities worldwide have established bike-sharing systems (BSS) that complement the conventional public transport systems. As the rapid spread of COVID-19 becoming a global pandemic disrupted urban mobility due to government-imposed lockdowns and the heightened fear of infection in crowded spaces, populations were increasingly less likely to use public transportation and instead shifted toward alternative transport systems, including BSS. In this study, we use probabilistic machine learning in a quasi-experimental research design to identify how the relevance of a comprehensive set of factors to predict the use of Bicing (the BSS in Barcelona) may have changed as COVID-19 unfolded. We unpack the key factors in predicting the use of Bicing, uncovering evidence of increasing bike-related built infrastructure (e.g., tactical urbanism), trip distance, and the income levels of neighborhoods as the most relevant predictors. Moreover, we find that the relevance of the factors in predicting Bicing usage has generally decreased during the global pandemic, suggesting altered societal behavior. Our study enhances the understanding of BSS and societal behavior, which can have important implications for developing resilient programs for cities to adopt sustainable practices through transport policy, infrastructure planning, and urban development.

Thermal Perception and Physiological Responses under Different Protection States in Indoor Crowded Spaces during the COVID-19 Pandemic in Summer

Currently, people in crowded indoor spaces are required to wear a variety of personal protective equipment to curb the spread of COVID-19. This study aimed to investigate the effects of wearing four types of personal protective equipment (unprotected, wearing masks, wearing face shield and wearing medical protective clothing) on human thermal perception and physiological responses in indoor crowded spaces in summer. The experiment was conducted in a climate chamber designed to simulate the indoor crowded spaces. Environmental parameters of climate chamber (air temperature, relative humidity and wind speed), physiological parameters of subjects (wrist skin temperature and pulse rate), and subjective perceptions (thermal sensation and thermal comfort) were collected during the experiment. The experimental results showed that medical protective clothing has the most obvious blocking effect on heat exchange between human and environment. Thermal sensation in state 4 (wearing medical protective clothing) was significantly (p &lt; 0.05) higher than that in other states. The study of physiological parameters showed that the wrist skin temperature and pulse rate under different protection states increased with the increase of room temperature. Through regression analysis, the thermal sensation estimation model of protective personnel in indoor crowded spaces based on wrist skin temperature and pulse rate was established. The adjusted R2 and RMSE of all models were above 82% and less than 1, indicating that the established thermal sensation model had a good prediction effect.

Nudging physical distancing behaviors during the pandemic: a field experiment on passengers in the subway stations of shiraz, Iran

BackgroundThe possibility of the emergence of new pandemics necessitates further research into using simple strategies to promote social distancing behaviors in public. Most of the current evidence on effectiveness of physical distancing interventions is based on self-report and measure of intention which will not necessarily predict actual behavior.MethodsA field experimental study was conducted in the subway stations of Shiraz, Southern Iran. The interventions were based on intuitions from protection motivation theory and consisted of using environmental nudges to notify the passengers of the pandemic situation (threat appeal) and a verbal advice on keeping a safe physical distance as an effective method of protection against COVID-19 (coping message). Average physical distancing was estimated as the number of steps between two consecutive passengers and was compared between interventions (n = 1045) and the control (n = 855) groups.ResultsA total of 1900 people riding on subway escalators were directly observed during two intervention conditions and the control condition. Under either threat or coping-based interventions, passengers were two times more likely (OR 2.0, 95%CI 1.5–2.7, P < 0.001) to keep a physical distance of at least 1.2 m from the traveler in front compared with those who did receive no intervention. The Kruskal-Wallis test revealed that there was a significant improvement in physical distancing behaviors with coping advice compared with threat appeal and the control conditions (χ2 = 120.84, df = 2, p < 0.001).ConclusionsOur findings suggest that simple and inexpensive theory-based interventions can be used in crowded public spaces to promote physical distancing within the context of the pandemic.

Monitoring social-distance in wide areas during pandemics: a density map and segmentation approach.

With the relaxation of the containment measurements around the globe, monitoring the social distancing in crowded public spaces is of great importance to prevent a new massive wave of COVID-19 infections. Recent works in that matter have limited themselves by assessing social distancing in corridors up to small crowds by detecting each person individually, considering the full body in the image. In this work, we propose a new framework for monitoring the social-distance using end-to-end Deep Learning, to detect crowds violating social-distancing in wide areas, where important occlusions may be present. Our framework consists in the creation of new ground truth social distance labels, based on the ground truth density maps, and the proposal of two different solutions, a density-map-based and a segmentation-based, to detect crowds violating social-distancing constraints. We assess the results of both approaches by using the generated ground truth from the PET2009 and CityStreet datasets. We show that our framework performs well at providing the zones where people are not following the social-distance, even when heavily occluded or far away from the camera, compared to current detection and tracking approaches.

Evaluating the learnability of vowel categories from infant-directed speech

Hyper-articulated vowels are considered a hallmark of infant-directed Speech (IDS) and are thought to facilitate acquisition. Consistent with this idea, vowels in IDS are reported to be more peripheral than in adult-directed speech (ADS) (e.g., Trainor and Desjardins, 2002; Liu et al., 2005). However, there are also reports that vowels in IDS are more variable (Cristia and Seidl, 2014; Martin et al., 2015). We evaluated the learnability of vowel categories from IDS in two languages—American English, which has a crowded vowel space, and Mexican Spanish, which has fewer vowels. First, we used k-means clustering, an unsupervised learning algorithm, to partition vowels based on spectral and duration measures from conversational IDS. The algorithm was trained on IDS from 5 English speakers (Providence Corpus, Demuth et al., 2006) and 12 Spanish speakers (Aly et al., 2016). The vowel categories extracted from IDS were used to classify ADS vowels from 5 English speakers from the Buckeye corpus and 12 Spanish speakers (Kim and Repiso Puigderlliura, 2021). Next, we switched the training and testing set, by training on ADS, and testing on IDS. If IDS is facilitative, we expect a higher accuracy of vowel classification with training on IDS rather than ADS.

Improving coarse-grained models of protein folding through weighting of polar-polar/hydrophobic-hydrophobic interactions into crowded spaces.

Herein were tested 7 hydrophobic-polar sequences in two types of 2D-square space lattices, homogeneous and correlated, the latter simulating molecular crowding included as a geometric boundary restriction. Optimization of 2D structures was carried out using a variant of Dill's model, inspired by convex function, taking into account both hydrophobic (Dill's model) and polar interactions, including more structural information to reach better folding solutions. While using correlated networks, degrees of freedom in the folding of sequences were limited; as a result in all cases, more successful structural trials were found in comparison to a homogeneous lattice. The majority of employed sequences were designed by our workgroup, two of them were folded with other approaches, and another is a modified version of a previous sequence, initial forms of the other two have been employed but without taking into account polar-polar contributions. Three of them are newly proposed, intended to test the conjoint hydrophobic-hydrophobic and polar-polar contributions in crowded spaces. One sequence turned out to be the most difficult of the seven folded, this perhaps due to intrinsic (i) degrees of freedom and (ii) motifs of the expected 2D HP structure. Meanwhile two-sequence, although optimal folding was not achieved for neither of the two approaches, folding with correlated network approach not only produced better results than homogeneous space, but for them the best values found with crowding were very close to the expected optimal fitness. In general, five sequences were better folded with medium lattice units for correlated media; instead, another two sequences were better folded with a bit larger degree of lattice unit, revealing that depending on the degrees of freedom and particular folding, motifs in each sequence would require tuned crowding to achieve better folding. Therefore, the main goal herein was to obtain a modified 2D HP lattice model to mimic folding of proteins or secondary structures, like β-sheets, taking into account both hydrophobic-hydrophobic and polar-polar interactions, and fold them in a crowded environment. This simple but enough construction would be conducted to determine the needed information to fold sequences in a sort of a minimal but complete heuristic model. Finally, we claim that all folded sequences into crowded spaces achieve better results than homogeneous ones.

Novel air sterilization process for clean air production and microbial spread limitation using protection devices.

This work aims to develop and simulate a novel process based on sterilizing natural air by heating at high temperatures followed by rapid cooling. The new sustainable process is called “Air Rapid Heating Rapid Cooling Sterilization” (ARHRCS). Thus, it can be used in Heating, Ventilation, and Air Conditioning (HVAC) systems in hospitals to produce safe air, free of pathogenic airborne microbes including bacteria and viruses such as tuberculosis (TB) and coronavirus (SARS-CoV-2). A crown fixed on the head of the medical staff may be connected to the HVAC system to produce a constant flow of clean laminar air. Hence, this crown is capable of keeping airborne microorganisms at a safe distance from Health Care Workers (HCWs), avoiding any potential microbial infection. Accordingly, HCWs will be able to work in more suitable and safe conditions, especially in high infection risk areas. Depending on its need, the newly developed process may be implemented in different other locations such as laboratories, malls, planes, buildings, and other crowded spaces. Further applications of this method may arise including its usage in the sterilization of recirculated air in biosafety cabinets and the development of a portable air sterilizing unit.

Experimental evidence for long-distance electrodynamic intermolecular forces.

Both classical and quantum electrodynamics predict the existence of dipole-dipole long-range electrodynamic intermolecular forces; however, these have never been hitherto experimentally observed. The discovery of completely new and unanticipated forces acting between biomolecules could have considerable impact on our understanding of the dynamics and functioning of the molecular machines at work in living organisms. Here, using two independent experiments, on the basis of different physical effects detected by fluorescence correlation spectroscopy and terahertz spectroscopy, respectively, we demonstrate experimentally the activation of resonant electrodynamic intermolecular forces. This is an unprecedented experimental proof of principle of a physical phenomenon that, having been observed for biomacromolecules and with long-range action (up to 1000 Å), could be of importance for biology. In addition to thermal fluctuations that drive molecular motion randomly, these resonant (and thus selective) electrodynamic forces may contribute to molecular encounters in the crowded cellular space.

CSCNet: Contextual semantic consistency network for trajectory prediction in crowded spaces

Trajectory prediction aims to predict the movement trend of the agents like pedestrians, bikers, vehicles. It is helpful to analyze and understand human activities in crowded spaces and widely applied in many areas such as surveillance video analysis and autonomous driving systems. Thanks to the success of deep learning, trajectory prediction has made significant progress. The current methods are dedicated to studying the agents’ future trajectories under the social interaction and the sceneries’ physical constraints. Moreover, how to deal with these factors still catches researchers’ attention. However, they ignore the Semantic Shift Phenomenon when modeling these interactions in various prediction sceneries. There exist several kinds of semantic deviations inner or between social and physical interactions, which we call the “Gap”. In this paper, we propose a Contextual Semantic Consistency Network (CSCNet) to predict agents’ future activities with powerful and efficient context constraints. We utilize a well-designed context-aware transfer to obtain the intermediate representations from the scene images and trajectories. Then we eliminate the differences between social and physical interactions by aligning activity semantics and scene semantics to cross the Gap. Experiments demonstrate that CSCNet performs better than most of the current methods quantitatively and qualitatively.

Social Momentum: Design and Evaluation of a Framework for Socially Competent Robot Navigation

Mobile robots struggle to integrate seamlessly in crowded environments such as pedestrian scenes, often disrupting human activity. One obstacle preventing their smooth integration is our limited understanding of how humans may perceive and react to robot motion. Motivated by recent studies highlighting the benefits of intent-expressive motion for robots operating close to humans, we describe Social Momentum (SM), a planning framework for legible robot motion generation in multiagent domains. We investigate the properties of motion generated by SM via two large-scale user studies: an online, video-based study ( N = 180) focusing on the legibility of motion produced by SM and a lab study ( N = 105) focusing on the perceptions of users navigating next to a robot running SM in a crowded space. Through statistical and thematic analyses of collected data, we present evidence suggesting that (a) motion generated by SM enables quick inference of the robot’s navigation strategy; (b) humans navigating close to a robot running SM follow comfortable, low-acceleration paths; and (c) robot motion generated by SM is positively perceived and indistinguishable from a teleoperated baseline. Through the discussion of experimental insights and lessons learned, this article aspires to inform future algorithmic and experimental design for social robot navigation.

Reduction of exposure to simulated respiratory aerosols using ventilation, physical distancing, and universal masking.

To limit community spread of SARS‐CoV‐2, CDC recommends universal masking indoors, maintaining 1.8 m of physical distancing, adequate ventilation, and avoiding crowded indoor spaces. Several studies have examined the independent influence of each control strategy in mitigating transmission in isolation, yet controls are often implemented concomitantly within an indoor environment. To address the influence of physical distancing, universal masking, and ventilation on very fine respiratory droplets and aerosol particle exposure, a simulator that coughed and exhaled aerosols (the source) and a second breathing simulator (the recipient) were placed in an exposure chamber. When controlling for the other two mitigation strategies, universal masking with 3‐ply cotton masks reduced exposure to 0.3–3 µm coughed and exhaled aerosol particles by >77% compared to unmasked tests, whereas physical distancing (0.9 or 1.8 m) significantly changed exposure to cough but not exhaled aerosols. The effectiveness of ventilation depended upon the respiratory activity, that is, coughing or breathing, as well as the duration of exposure time. Our results demonstrate that a layered mitigation strategy approach of administrative and engineering controls can reduce personal inhalation exposure to potentially infectious very fine respiratory droplets and aerosol particles within an indoor environment.