Number Of Collisions Research Articles

Children’s safe routes to school: Real and perceived risks, and evidence of an incapacity-incapability space

There is a general consensus that children and adolescents should ideally travel to school actively and independently. Yet, in many parts of the world, real and perceived traffic risks represent a major barrier to walking, cycling, or the use of scooters. As the perspectives of children and adolescents on perceived dangers are insufficiently understood, this quantitative-qualitative study compares injury data for 2019-2021 with questionnaires answered by school management (n=40 school managers) and focus-group interviews with students aged 6-17 (n=40) in the city of Freiburg, Germany. The triangulation indicates that a significant number of collisions and injuries in traffic appear to go unreported, and that school routes are characterized by insecurity and perceived dangers. The analysis suggests that perceptions of risk change with age, and in reflection of influences including cognitive ability and motor skills, social environment and attitudes, transport mode, and technology adoption. Results are conceptualized as an incapacity-incapability space, indicating that relative risk exposure is highest for younger children (5-9 years), and for teenagers (12-16 years). Findings have implications for the study of traffic risks, urban design and transport planning and policy.

The effects of an electronic head-mounted display in vision rehabilitation for patients with tunnel vision

PurposeTo investigate the effect of a new head-mounted electronic visual aid-Acesight on improving visual function and daily activities in patients with tunnel vision.Methods57 patients with tunnel vision participated in this study. The visual field (VF), visual acuity (VA), search ability, time of finding people from the side (TFPS), walking ability, and the subjective feelings of patients with and without Acesight were measured.Results15 (36%) patients thought Acesight was “helpful”, 16 (28%) thought it was “a little help”, and 26 (46%) believed that it was “not helpful.” The proportion of people aged < 60 years found Acesight helpful was higher. When wearing Acesight, the average horizontal VF diameter (°) (35.54[8.72]) and vertical VF diameter (°) (26.63[5.38]) were larger than those without visual aids (20.61[9.22], 18.19[6.67]) (P all < 0.001). The average TFPS before and while wearing the Acesight was 1.77s(0.32) and 1.19s(0.29), respectively (t = 14.28, P < 0.001). The average search times, number of collisions, walking speeds when wearing the Acesight were not statistically different from those without visual aids (P all > 0.05).ConclusionMore than half of patients with tunnel vision found the Acesight helpful, and a higher proportion of those aged < 60 years old found it helpful. Acesight can expand the horizontal and vertical VF of patients with tunnel vision and can enable patients to detect objects coming from the side earlier.Trial registrationChiCTR2000028859; Date of registration: 2020/1/5; URL: http://www.chictr.org.cn/showproj.aspx?proj=47129

The value of collision feedback in robotic surgical skills training

Collision feedback about instrument and environment interaction is often lacking in robotic surgery training devices. The PoLaRS virtual reality simulator is a newly developed desk trainer that overcomes drawbacks of existing robot trainers for advanced laparoscopy. This study aimed to assess the effect of haptic and visual feedback during training on the performance of a robotic surgical task. Robotic surgery-naïve participants were randomized and equally divided into two training groups: Haptic and Visual Feedback (HVF) and No Haptic and Visual Feedback. Participants performed two basic virtual reality training tasks on the PoLaRS system as a pre- and post-test. The measurement parameters Time, Tip-to-tip distance, Path length Left/Right and Collisions Left/Right were used to analyze the learning curves and statistically compare the pre- and post-tests performances. In total, 198 trials performed by 22 participants were included. The visual and haptic feedback did not negatively influence the time to complete the tasks. Although no improvement in skill was observed between pre- and post-tests, the mean rank of the number of collisions of the right grasper (dominant hand) was significantly lower in the HVF feedback group during the second post-test (Mean Rank = 8.73 versus Mean Rank = 14.27, U = 30.00, p = 0.045). Haptic and visual feedback during the training on the PoLaRS system resulted in fewer instrument collisions. These results warrant the introduction of haptic feedback in subjects with no experience in robotic surgery. The PoLaRS system can be utilized to remotely optimize instrument handling before commencing robotic surgery in the operating room.

A Quality Management Method for Prefabricated Building Design Based on BIM and VR-Integrated Technology

Quality management in the design phase is crucial for determining the overall quality of prefabricated buildings. However, traditional design methods can no longer meet the complex design, component, and nodal requirements of prefabricated buildings. This study proposes a quality management framework for the prefabricated building design phase based on building information modeling (BIM) and virtual reality (VR) technologies to enhance design precision and satisfaction. Applying this framework to a prefabricated building project in Shenzhen, China, it was found that compared to traditional 2D drawing methods, the design issues feedback during drawing reviews decreased by 41.35%. Compared to solely using BIM technology, the number of design collisions identified through collision detection increased by 28.35%, and feedback on design issues during drawing reviews decreased by 15%. Furthermore, the framework was tested to prove its usability, effectiveness, and functionality. The framework, integrating the rich architectural information of BIM with the immersive experience of VR, contributes to focusing on the design process, improving design tools, optimizing design workflows, significantly reducing design errors, and enhancing the quality of prefabricated buildings.

Design and evaluation of a smart passive dynamic arm support for robotic-assisted laparoscopic surgery

Surgeons performing robotic-assisted laparoscopic surgery experience physical stress and overuse of shoulder muscles due to sub-optimal arm support during surgery. The objective is to present a novel design and prototype of a dynamic arm support for robotic laparoscopic surgery to evaluate its ergonomics and performance on the AdLap-VR simulation training device. The prototype was designed using the mechanical engineering design process: Technical requirements, concept creation, concept selection, 3D-design and built of the prototype. A crossover study was performed on a marble sorting task on the AdLap-VR. The first group performed four trials without the arm support, followed by four trials with the arm support, and the other group executed the sequence vice versa. The performance parameters used were time to complete (s), path length (mm), and the number of collisions. Afterward, the participants filled out a questionnaire on the ergonomic experience regarding both situations. 20 students executed 160 performed trials on the AdLap-VR Significant decreases in the subjective comfort parameters mental demand, physical demand, effort and frustration were observed as a result of introducing the novel arm support. Significant decreases in the objective performance parameters path length and the number of collisions were also observed during the tests. The newly developed dynamic arm support was found to improve comfort and enhance performance through increased stability on the robotic surgery skills simulator AdLap-VR.

Trajectory optimization with hybrid probabilistic roadmap approach to achieve time efficient navigation of unmanned vehicles in unstructured environment

PurposeThis paper aims to focus on solving the path optimization problem by modifying the probabilistic roadmap (PRM) technique as it suffers from the selection of the optimal number of nodes and deploy in free space for reliable trajectory planning.Design/methodology/approachTraditional PRM is modified by developing a decision-making strategy for the selection of optimal nodes w.r.t. the complexity of the environment and deploying the optimal number of nodes outside the closed segment. Subsequently, the generated trajectory is made smoother by implementing the modified Bezier curve technique, which selects an optimal number of control points near the sharp turns for the reliable convergence of the trajectory that reduces the sum of the robot’s turning angles.FindingsThe proposed technique is compared with state-of-the-art techniques that show the reduction of computational load by 12.46%, the number of sharp turns by 100%, the number of collisions by 100% and increase the velocity parameter by 19.91%.Originality/valueThe proposed adaptive technique provides a better solution for autonomous navigation of unmanned ground vehicles, transportation, warehouse applications, etc.

Low Latency Signature-Based 4-Step Random Access Procedure for Massive Machine-Type Communications

Massive machine-type communication (mMTC) is one of the major services in the 5G new radio (NR) system. In the mMTC application scenarios, many machine-type communication devices (MTCDs) communicate with each other or through an MTC server. However, how to solve the problem of excessive MTCDs accessing the network simultaneously is an important task. To overcome the large number of random access collisions and retransmission problems, this paper proposes a method to solve the mMTC random access problem. The proposed method consists of two parts, modified Contention Based Random Access (CBRA) with 4-step RA type and 4-step Signature RA type. With the modified CBRA with 4-step RA type, each MTCD will obtain the information to generate the signature. After that, the 4-step Signature RA type is used for MTCDs to proceed with the random access with the gNB through the generated signatures. In our proposed method, the average number of false positives and average process time are evaluated under different numbers of active MTCDs and different parameter values for the signature generation. Besides, the average number of preamble attempts and average process time are used as the metrics to compare the proposed scheme with the 5G NR 4-step RA type. Finally, simulation results show that the proposed scheme performs better than the 5G NR 4-step RA type in the mMTC scenarios.

How COVID-19 impacted the temporal and spatial distribution of collision hotspots

This research examines the spatial and temporal shift in collision hotspots caused by the COVID-19 pandemic, considering different collision severities. The Getis-Ord statistic was utilized to create spatial models and generate map outputs for 2019 and 2020. Two distinct approaches were employed: using a census tract shapefile (provided) and creating fishnet polygons measuring 500 m by 500 m. Results showed fewer hotspots outside Edmonton's central core, while fatal collisions were concentrated close to the core. This intriguing finding suggests that COVID-19 restrictions led to more aggressive driving behaviour near the centre, contributing to a rise in fatal collision numbers. The study found a significant reduction in traffic collisions in April 2020, with a 58% decrease compared to the previous year. The research highlights the pandemic's impact on road safety, emphasizing the importance of reducing traffic volume and advocating for traffic restrictions and control strategies, multi-modal planning, and efficient pricing strategies within Vision Zero for improved road safety.

Students' participation in social networks' conflicts (based on the materials of a sociological study of Barnaul universities)

In the modern world, there is a significant number of collisions in the Internet space, which occur not only in interpersonal communication online, but also on various social networks with a large number of participants. Almost any social network that supports the function of discussion, commenting on the information provided, allows you to observe a number of pre-conflict and conflict situations. Despite the fact that the space in which communication takes place is virtual, the consequences of conflicts in it can be more than real, both for an individual and for a number of participants. Conflict situations can have an impact on the daily life of opponents and collectively affect social processes in society. In his work, the author studies in depth the nature of conflicts in social networks. The study was implemented through a quantitative method of collecting information – a survey in the form of a questionnaire. The general totality of the study was made up of students from Barnaul who are users of social networks. The study was conducted using a selective method. The sample totals 367 respondents. The sample size was determined by the capabilities of the researcher. A single-stage sampling was used, the selection unit was specific students. According to the results of the study, the following conclusions were made. Firstly, the vast majority of students use social networks every day, but only half of them have participated or are involved in conflicts. Secondly, students most often conflict on social networks with strangers and in community comments. Thirdly, trolling is still one of the important problems of social networks. A significant part of the (interviewed) students became victims of trolls. Fourth, most of the conflicts in social networks in which students participate are short-lived and occur through verbal debates. Fifth, most students choose a more "peaceful" behavior strategy. Sixth, many students determine the beginning of a conflict in a social network by negative emotions from interaction and consider the presence of physical distance to be the main feature of the described conflicts.

Atomic-level insight into process and mechanism of ion beam machining on aluminum optical surface

Polycrystalline Al workpieces go through a complex surface atom sputtering and surface/subsurface atom diffusion throughout the ion beam machining process that plays a critical role in determining machining quality of optical mirror surfaces. Here, we leverage molecular dynamics method for the first time to reveal the machining mechanism and the polycrystalline effect of aluminum during ion beam sputtering, in term of cascade collision, atom trajectory, sputtering yield, and surface characteristic. Polycrystalline Al presents a significant low potential energy state, leading to milder cascade collision and weaker sputtering effects than monocrystalline Al during ion beam machining. The atom trajectory demonstrates irregular variation as the atom diffusion is blocked by grain boundary (GB) in polycrystalline Al, leading to the relief microstructure and poor surface quality. With incident ions increasing, the GBs are broken and atom diffusion enhancing, as well as lower subsurface defects and better finishing surface quality. The microscopic morphology evolves into gravel microstructure. Simulation results also reveal that atom diffusion will benefit from high ion concentration and low ion energy. Sputtering yield variation is more sensitive to ion energy. To acquiring better finishing surface quality of Al without influencing machining efficiency, ion concentration must be increased while the ion energy needs to be decreased appropriately but a large number of cascading collisions need to be ensured.

Tactical Conflict Avoidance of Manned Traffic - Display Concepts for UAV Pilots

The number of collisions between manned and unmanned aerial vehicles (UAVs) has risen due to the increased use of UAVs. Pilots of manned aircraft can visually detect the usually much smaller UAVs only very late or not at all, which is why UAVs are required to avoid manned aircraft in lower airspace by most regulations. For the task of collision avoidance, the UAV pilot needs appropriate traffic awareness. While operating UAVs within the visual line of sight (VLOS), the UAV pilot can monitor the surrounding traffic himself, but operation beyond the visual line of sight (BVLOS) requires an additional airspace observer or a supporting detect-and-avoid system. In this work, a traffic display concept supporting UAV pilots is derived and proposed using the human-centered design process. Commonly used collision avoidance displays of manned and unmanned aviation are reviewed and the user context for the proposed traffic display is introduced. An online survey is conducted to gather user preferences for several 2D graphical elements of the traffic display. 25 experienced UAV pilots participated in the survey. The data is analyzed using Gwet’s AC1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$AC_1$$\\end{document} agreement coefficient. Overall, fair agreement can be observed with individual coefficients for different 2D graphical elements ranging from poor to almost perfect agreement. With a developed heuristic, preferred 2D graphical elements are extracted and combinations reviewed to derive a complete traffic display design. The proposed traffic display design, based on user preferences, will be implemented for further evaluation in human-in-the-loop experiments.

Comparison of the number of pedestrian and cyclist injuries captured in police data compared with health service utilisation data in Toronto, Canada 2016–2021

IntroductionPedestrian and cyclist injuries represent a preventable burden to Canadians. Police-reported collision data include information on where such collisions occur but under-report the number of collisions. The primary objective of...

Relevance of inter-particle interaction in directed energy deposition powder stream

Blown powder dynamics is one of the aspects of Directed Energy Deposition (DED) with a major influence on deposition quality and potential for improvement in simulation. Most currently employed computational models discard powder grain collisions as negligible, although little explicit evidence for that claim exists. A Discrete Element Method approach is thus employed in the present work to simulate the actual number of grain collisions in a powder stream of a commercial discrete coaxial nozzle and how that number varies with the key processing parameters. While the number of powder grain collisions is found to in fact be negligible at one side of the usable parameter spectrum, the opposite side results in as many as 84% of all the powder grains being involved in inter-granular collisions with an average rebound angle of 14°, challenging the established hypothesis of the negligibility of this phenomena.

Navigating Paramedics' Safety

Background: Ambulance drivers are more likely to be involved in fatal or injury collisions compared to other professional drivers.&#x0D; Study Objective: This study is a retrospective study aimed to describe factors involved in paramedics’ collisions.&#x0D; Method: Spanning over 10 years of data (2010-2019) from a paramedic agency covering Montreal (Qc, Canada), links between the number of ambulance injuries and non-injury collisions and diverse characteristics like experience, sex, and age of paramedics, day and time of the collision, weather and surface conditions, type of environment, and type of driving activity. The distribution of characteristics involved in the severity of collisions is presented with descriptive analysis. The evaluation of trends of monthly and yearly ambulance collisions is conducted using the Mann-Kendal test. The logit model is also used to examine the effect of such factors on the odds of collision severity.&#x0D; Results: The results show although there is no significant reduction trend for the monthly ambulance collisions, the trend of incidence of annual non-injury collisions per paramedic is significantly decreasing. Also, young drivers with less experience are more involved in multiple collisions compared to their experienced colleagues. Furthermore, 62% of injury collisions happened when paramedics are responding to an emergency call. The logit model confirms a decrease in the odds of injury collisions (odds ratio: 0.48) during non-emergency activities. Also, intersections and traffic lights are the riskiest locations regarding injury collisions (43.5%, and 51%, respectively). In this case, collisions occurring at traffic lights can increase the odds of severity by 597%.&#x0D; Conclusion: This study exemplifies that preventive policy regarding paramedics (e.g., training programs) should focus on younger and less experienced paramedics, and risky locations, especially while driving on emergency calls. More oriented awareness and training programs for emergency respondents are required to reduce the number of work-related collisions.

Influence of keel impacts and laying hen behavior on keel bone damage

Keel bone damage, which presents as fractures and/or deviations of the keel, has been detected in laying hens housed in all types of systems. Factors leading to keel bone damage in hens housed with limited vertical space, such as those housed in furnished systems, are not well understood, and are the topic of this study. Ten focal hens from each of 12 furnished cages (4 rooms of 3 cages) were fitted with keel mounted tri-axial accelerometers. Their behavior was video recorded continuously over two 3-wk trials: the first when the hens were between 52 and 60 wk of age, and the second approximately 20 wk later. The integrity of each hen's keel was evaluated at the start and end of each 3-wk trial using digital computed tomography. We identified predominant behaviors associated with acceleration events sustained at the keel (collisions, aggressive interactions and grooming) by pairing accelerometer outputs with video data. For each recorded acceleration event we calculated the acceleration magnitudes as the maximum summed acceleration recorded during the event, and by calculating the area under the acceleration curve. A principle components analysis, which was used as a data reduction technique, resulted in the identification of 4 components that were used in a subsequent regression analysis. A key finding is that the number of collisions a hen has with structures in her environment, and the number of aggressive interactions that a hen is involved, each affect the likelihood that she will develop 1 or more fractures within a 3-wk time span. This relationship between hen behavior and keel fracture formation was independent of the magnitude of acceleration involved in the event. Observed behavior did not have an impact on the formation of keel bone deviations, further supporting reports that the mechanisms underlying the 2 types of keel bone damage are different.

FusionPlanner: A multi-task motion planner for mining trucks via multi-sensor fusion

In recent years, significant achievements have been made in motion planning for intelligent vehicles. However, as a typical unstructured environment, open-pit mining attracts limited attention due to its complex operational conditions and adverse environmental factors. A comprehensive paradigm for unmanned transportation in open-pit mines is proposed in this research. Firstly, we propose a multi-task motion planning algorithm, called FusionPlanner, for autonomous mining trucks by the multi-sensor fusion method to adapt both lateral and longitudinal control tasks for unmanned transportation. Then, we develop a novel benchmark called MiningNav, which offers three validation approaches to evaluate the trustworthiness and robustness of well-trained algorithms in transportation roads of open-pit mines. Finally, we introduce the Parallel Mining Simulator (PMS), a new high-fidelity simulator specifically designed for open-pit mining scenarios. PMS enables the users to manage and control open-pit mine transportation from both the single-truck control and multi-truck scheduling perspectives. The performance of FusionPlanner is tested by MiningNav in PMS, and the empirical results demonstrate a significant reduction in the number of collisions and takeovers of our planner. We anticipate our unmanned transportation paradigm will bring mining trucks one step closer to trustworthiness and robustness in continuous round-the-clock unmanned transportation.

Effects of Orbit Raising and Deorbiting in Source-Sink Evolutionary Models

The sustainability of the low-Earth-orbit (LEO) environment is threatened by the growing number of anthropogenic space objects planned to be launched in the coming years. This paper investigates the evolution of objects residing in LEO through the MIT Orbital Capacity Assessment Tool (MOCAT), an evolutionary multishell, multispecies source-sink model. The proposed novelty considers the flow of objects crossing multiple shells during orbit raising and deorbiting maneuvers, modeled through the secular variation of the semimajor axis under a low-thrust continuous applied control. To this aim, a higher-fidelity MOCAT version, including active satellites, derelicts, debris, and rocket bodies, has been developed and used. The results demonstrate that incorporating orbit transfer fluxes into the model results in a higher number of collisions, which leads to a greater quantity of debris and poses a greater threat to the safety of LEO.

Perception and satisfaction of blind individuals regarding an electronic cane prototype with a wearable haptic device.

This study aimed to evaluate the perception and degree of satisfaction of blind individuals regarding an electronic cane prototype with a wearable haptic interface. Two scenarios with different obstacles were created to conduct tests with the canes (the user's cane and the prototype one). The perception and satisfaction of participants regarding the electronic cane were assessed using a questionnaire, the number of collisions during the tests, and the time each individual took to complete the course in each scenario. Ten blind individuals who used the white cane participated in this study. Eight were males, and two were females. Their age ranged from 23 to 43 (average 32.3 ± 7.13 years and median 32 years). There was a tendency for fewer collisions with ground obstacles when the electronic cane was used than when the white cane was used. However, there was no statistically significant difference between the number of collisions and the course completion time in each scenario with either canes tested. Overall, the perception and satisfaction of individuals regarding the prototype used were positive.

Electron transport characteristics in water under electrostrictive effect

The transport characteristics of electrons are crucial for the initiation and development of pulse discharge in water. In this work, we develop a physical model of electron transport that consides elastic and inelastic collision cross sections. The purpose of this study is to investigate frequency variations of elastic collisions, ionization and excitation collisions with different initial electron energy values, and to explore the characteristic of electron energy loss in water. The Monte Carlo method is employed to track structure characteristics of electron transmission and scattering under varying energy values. The results show that the electrons of lower energy (~20 eV) are significantly impacted by the water molecule scattering, hence their transmission capacities are weakened. When the incident energy of electron reaches 100 eV, the scattering deviation distance is roughly equivalent to the transmission depth, about 6–8 nm, and the maximum deviation angle &lt;i&gt;θ&lt;/i&gt;&lt;sub&gt;shift&lt;/sub&gt; ~ 60°. When the electron incident energy is in a range of 10–1000 eV, the number of elastic collisions is much greater than the number of excitation and ionization collisions, and the number of ionization collisions and excitation collisions increases significantly with the increase of electron energy. The higher the electron incident energy, the greater the energy loss is. However, the energy loss decreases sharply with the extension of penetration distance. For the ionization collision, the average ionization energy loss, &lt;i&gt;W&lt;/i&gt;, decreases rapidly with the increase of electron energy, and ultimately maintains at a level of 20–30 eV, which is consistent with the experimental results reported.

How to Launch a Powerful Side-Channel Collision Attack?

A cryptographic implementation produces very similar power leakages when fed with the same input. Side-channel collision attacks exploit these similarities to establish the relationship between sub-keys and improve the efficiency of key recovery. Benefiting from independence of leakage model, they play an important role in non-profiled setting. However, performance of existing approaches against single collision value is still sub-optimal and optimization is promising. Motivated by this, we first theoretically analyze the mathematical dependency between the number of collisions and the number of encryptions, and propose an efficient side-channel attack named Collision-Paired Correlation Attack (CPCA) to guarantee that the side with fewer samples in a collision is completely paired in low noise scenario. This allows overcoming the inefficient utilization of information in existing works. Moreover, to further employ underlying informativeness, we maximize collision pairs as many as possible. This optimization significantly improves performance of CPCA and thereby extends it to large noise scenarios. Finally, to achieve moderate computational complexity, two equivalent variants of CPCA are investigated to address the potential problem of limited computing resources. Our further theoretical study illustrates that CPCA provides the upper security bound of Correlation-Enhanced Collision Attack (CECA), and experimental results fully verify its superiority.