Polar Collision Grids: Effective Interaction Modelling for Pedestrian Trajectory Prediction in Shared Space Using Collision Checks

Predicting pedestrians' trajectories is a crucial capability for autonomous vehicles' safe navigation, especially in spaces shared with pedestrians. Pedestrian motion in shared spaces is influenced by both the presence of vehicles and other pedestrians. Therefore, effectively modelling both pedestrian-pedestrian and pedestrian-vehicle interactions can increase the accuracy of the pedestrian trajectory prediction models. Despite the huge literature on ways to encode the effect of interacting agents on a pedestrian's predicted trajectory using deep-learning models, limited effort has been put into the effective selection of interacting agents. In the majority of cases, the interaction features used are mainly based on relative distances while paying less attention to the effect of the velocity and approaching direction in the interaction formulation. In this paper, we propose a heuristic-based process of selecting the interacting agents based on collision risk calculation. Focusing on interactions of potentially colliding agents with a target pedestrian, we propose the use of time-to-collision and the approach direction angle of two agents for encoding the interaction effect. This is done by introducing a novel polar collision grid map. Our results have shown predicted trajectories closer to the ground truth compared to existing methods (used as a baseline) on the HBS dataset.Comment: Accepted for publication as a conference paper in IEEE Intelligent Transportation Systems Conference (ITSC), 202

Pedestrian Trajectory Prediction in Pedestrian-Vehicle Mixed Environments: A Systematic Review

Planning an autonomous vehicle's (AV) path in a space shared with pedestrians requires reasoning about pedestrians' future trajectories. A practical pedestrian trajectory prediction algorithm for the use of AVs needs to consider the effect of the vehicle's interactions with the pedestrians on pedestrians' future motion behaviours. In this regard, this paper systematically reviews different methods proposed in the literature for modelling pedestrian trajectory prediction in presence of vehicles that can be applied for unstructured environments. This paper also investigates specific considerations for pedestrian-vehicle interaction (compared with pedestrian-pedestrian interaction) and reviews how different variables such as prediction uncertainties and behavioural differences are accounted for in the previously proposed prediction models. PRISMA guidelines were followed. Articles that did not consider vehicle and pedestrian interactions or actual trajectories, and articles that only focused on road crossing were excluded. A total of 1260 unique peer-reviewed articles from ACM Digital Library, IEEE Xplore, and Scopus databases were identified in the search. 64 articles were included in the final review as they met the inclusion and exclusion criteria. An overview of datasets containing trajectory data of both pedestrians and vehicles used by the reviewed papers has been provided. Research gaps and directions for future work, such as having more effective definition of interacting agents in deep learning methods and the need for gathering more datasets of mixed traffic in unstructured environments are discussed.Comment: Published in IEEE Transactions on Intelligent Transportation System

Gender Determination Using Diagnostic Values of Foramen Magnum

Background: Foramen magnum is a big hole in the base of the skull. Its appearance can be useful in gender determination. So far, no study has been conducted in Iran that evaluates the value of foramen magnum in sex determination and calculates the cut-off points. This study aimed to evaluating of diagnostic value of the foramen magnum and to calculate the cut-off points for sex determination.Methods: In this cross sectional study 50 male and 50 female patients referring to the radiology department of Rasol Akram Hospital in Tehran were evaluated. The required information about the sagittal diameter, transverse diameter, and diameter of foramen magnum were assessed by brain CT scan. Chi-square and independent t test was used for the comparison of different shapes and diameters between the sexes. ROC curve was used to determine the optimal cut-off point for each indicator.Results: The best cut-off point to distinguish males from females along the anterior-posterior foramen magnum was calculated as 36.45 mm, at the transverse diameter of 30.4 mm. The proper cut-off points for the area of the foramen magnum were 877.477 mm2 and 870.29 mm2, based on the Teixeria formula and Routal formula respectively. Overall, the accuracy of these indicators was calculated as 85%.Conclusion: Based on the results of this study using CT scans images, the diameter of the foramen magnum and its area had a high accuracy in sex determination

Novel approach of vaccination against Brucella abortus 544 based on a combination of fusion proteins, human serum albumin and brucella abortus Lipopolysaccharides.

Lipopolysaccharide (LPS) of Brucella abortus is an essential component for developing the subunit vaccine against brucellosis. B. abortus LPS was extracted by n-butanol, purified by ultracentrifugation and detoxified by alkaline treatment. Pyrogenicity and toxicity of B. abortus LPS and detoxified–LPS (D-LPS) were analyzed and compared with LPS of E. coli. Different groups of mice were immunized intraperitoneally with purified B. abortus LPS, D-LPS, a combination of LPS with human serum albumin (LPS-HSA) and B. abortus S19 bacteria; besides, control mice were inoculated with sterile saline. Two doses of vaccine were given 4 weeks apart. Mice were challenged intraperitoneally with virulent B. abortus 544 strain 4 weeks after the second dose of vaccine. Sera and spleens of mice were harvested 4 weeks after challenge. LPS-B. abortus was 10,000-fold less potent in LAL test and 100-fold less potent in eliciting fever in rabbits than in E. coli LPS. And D-LPS was very less potent in LAL test and eliciting fever in rabbits ordinary LPS. The antibody titer of anti-LPS immunoglobulin G (IgG) was higher than D-LPS. However, mice immunized with either LPS, D-LPS or LPS-HSA vaccines showed a significant protection against infection of the spleen (p<0.01). There was no significant difference between mice immunized with LPS and D-LPS in terms of protection (p<0.99). Therefore, it was concluded that D-LPS and LPS-HSA for B. abortus can be used as safer and more potent vaccines than ordinary LPS-B. abortus vaccine

A study on important factors influencing innovation in service: A case study of hotel industry

Hotel industry plays important role on developing tourism industry and having better services in this industry always help increase market share. The proposed study of this paper considers the effects of four variables including collaboration with staff, collaboration with customers, collaboration with partners and business owners and finally mechanism of integration of knowledge on innovation on service. The population of this survey includes 259 hotels where we send our questionnaire to 179 and manage to collect 170 ones. Cronbach alpha for four variables including collaboration with staff, collaboration with customers, collaboration with partners and business owners and finally mechanism of integration of knowledge were calculated as 0.78, 0.865, 0.743 and 0.890, respectively. The proposed study uses structural equation modeling to study the relationship between independent variables and dependent variable and the effects of four variables are confirmed when the level of significance is five percent

Solar-thermal conversion and steam generation: a review

Recently, steam generation systems based on solar-thermal conversion have received much interest, and this may be due to the widespread use of solar energy and water sources such as oceans and lakes. The photo-thermal desalination system becomes attractive as it can convert absorbed solar light energy into thermal energy and realise the desalination and water purification of saline water through the evaporation process. In this paper, the research status of solar-thermal conversion materials such as metal-based materials, semiconductor materials, carbon-base materials, organic polymer materials, composite photo-thermal materials and their solar-thermal conversion mechanism in recent years are reviewed. The physical process and evaluation principle of solar-thermal conversion are both carefully introduced. The methods of optimising thermal management and increasing the evaporation rate of a hybrid system are also introduced in detail. Four main applications of solar-thermal conversion technologies (seawater desalination, wastewater purification, sterilisation and power generation) are discussed. Finally, based on the above analysis, the prospects and challenges for future research in the field of desalination are discussed from an engineering and scientific viewpoint to promote the direction of research, in order to stimulate future development and accelerate commercial application