Virtual Reality as Navigation Tool: Creating Interactive Environments For Individuals With Visual Impairments

Research into the creation of assistive technologies is increasingly incorporating the use of virtual reality experiments. One area of application is as an orientation and mobility assistance tool for people with visual impairments. Some of the challenges are developing useful knowledge of the user’s surroundings and effectively conveying that information to the user. This thesis examines the feasibility of using virtual environments conveyed via auditory feedback as part of an autonomous mobility assistance system. Two separate experiments were conducted to study key aspects of a potential system: navigation assistance and map generation. The results of this research include mesh models that were fitted to the walk pathways of an environment, and collected data that provide insights on the viability of virtual reality based guidance systems

Explicit Energy-Minimal Short-Term Path Planning for Collision Avoidance in Crowd Simulation

In traditional crowd simulation methods, global path planning (GPP) and local collision avoidance (LCA) were mostly used to advance pedestrians toward their own goals without colliding. However, we found that using those methods in bidirectional flows can force a pedestrian to get stuck among the incoming people, walk through the congestion, or even unintentionally occupy in a dense area, although more comfortable passageway exists. These odd behaviors are usually produced and simply noticeable in bidirectional case. This paper aims at reducing these artifacts to achieve more behavioral fidelity, by adding the explicit metabolic-energy-minimal short-term path planning (MEM) in between GPP and LCA. For energy analysis, the optimal control theory with the objective energy function from the study of biomechanics was employed, which finally leads to the useful optimal walking characteristics for the pedestrians. The simulation results show that the pedestrians with MEM can adapt their moving to avoid the congestion, resulting in more promising lane changing and overtaking behaviors. Even though MEM was mainly developed to deal with the artifacts in bidirectional flows, it can be extended with a little modification and can produce significant behavioral improvement for multi-directional case as shown in the last part of the paper

Generating Pedestrian Trajectories Consistent with the Fundamental Diagram Based on Physiological and Psychological Factors

Pedestrian crowds often have been modeled as many-particle system including microscopic multi-agent simulators. One of the key challenges is to unearth governing principles that can model pedestrian movement, and use them to reproduce paths and behaviors that are frequently observed in human crowds. To that effect, we present a novel crowd simulation algorithm that generates pedestrian trajectories that exhibit the speed-density relationships expressed by the Fundamental Diagram. Our approach is based on biomechanical principles and psychological factors. The overall formulation results in better utilization of free space by the pedestrians and can be easily combined with well-known multi-agent simulation techniques with little computational overhead. We are able to generate human-like dense crowd behaviors in large indoor and outdoor environments and validate the results with captured real-world crowd trajectories

Group Pathfinding Using Group Division

Pathfinding is an important problem in video games. Good pathfinding strategy, for both player characters and non-player characters is one of the key differences between a good game and a less successful one. Finding the shortest path for one character unit in a given environment is a very well-known problem for which there exist many solutions. When a group of units wants to pass through the map, the problem becomes more complicated. This thesis introduces the Reduced Wait Time (RWT) algorithm which is a multi-unit path planning algorithm where units can take several paths instead of just the shortest one to reduce the overall waiting time of the units in queues along the path and therefore reduces the total time needed to pass all units through the map. The main goal of this thesis is propose the pathfinding algorithm RWT to reduce the total time for a group of units to pass a route. The simulation results shows that the RWT algorithm not only reduces the time to pass by decreasing the waiting time, but also can reduce the number of collisions between units which reduces the CPU usage which is another important consideration for games. Using the RWT algorithm also gives an opportunity to the level designers to be able to implement strategic pathfinding in games. Different routes have different strategic advantages and disadvantages over each other; being able to send units through different paths enables designers to consider strategic path-planning. The RWT algorithm was implemented using the Unity game engine and tested on a number of randomly generated example maps. The experimental results were compared with the results from other related algorithms such as Local Repair A* and Maximum Flow to show that the RWT algorithm works better than other studied algorithms

Спосіб пошуку шляху за допомогою Unity DOTS

Магістерська дисертація присвячена вивченню проблеми побудови шляху в довільному просторі за допомогою стеку технологій Unity DOTS. В роботі розглянуто та проведено аналіз основних сучасних методів пошуку шляху, методи моделювання середовища для пошуку шляху, процеси обчислення та відтворення шляху. Розглянуто засоби стеку технологій DOTS, проведено аналіз особливостей використання стеку технологій для вирішення та оптимізації задачі пошуку шляху. Окрім цього розглянуто процес побудови системи, що дозволяє користувачу контролювати сутності, що виконують пошук шляху. Основним аспектом роботи було створення системи пошуку шляху в довільному просторі, створення системи контролю сутностей, оптимізація швидкодії способу пошуку шляху за допомогою стеку DOTS.The master's thesis is devoted to the study of the problem of path construction in an arbitrary space using the Unity DOTS technology stack. The work considers and analyzes the main modern methods of pathfinding, methods of modeling of the environment for pathfinding, the processes of calculation and reproduction of the way. The tools of the DOTS technology stack were considered, and the features of using the technology stack to solve and optimize the pathfinding problem were analyzed. In addition, the process of building a system that allows the user to control the entities performing the path search is considered. The main aspect of the work was the creation of a pathfinding system in an arbitrary space, the creation of an entity control system, the optimization of the productivity of the pathfinding method using the DOTS stack

Pedestrian velocity obstacles: pedestrian simulation through reasoning in velocity space

We live in a populous world. Furthermore, as social animals, we participate in activities which draw us together into shared spaces -- office buildings, city sidewalks, parks, events (e.g., religious, sporting, or political), etc. Models that can predict how crowds of humans behave in such settings would be valuable in allowing us to analyze the designs for novel environments and anticipate issues with space utility and safety. They would also better enable robots to safely work in a common environment with humans. Furthermore, credible simulation of crowds of humans would allow us to populate virtual worlds, helping to increase the immersive properties of virtual reality or entertainment applications. We propose a new model for pedestrian crowd simulation: Pedestrian Velocity Obstacles (PedVO). PedVO is based on Optimal Reciprocal Collision Avoidance (ORCA), a local navigation algorithm for computing optimal feasible velocities which simultaneously avoid collisions while still allowing the agents to progress toward their individual goals. PedVO extends ORCA by introducing new models of pedestrian behavior and relationships in conjunction with a modified geometric optimization planning technique to efficiently simulate agents with improved human-like behaviors. PedVO introduces asymmetric relationships between agents through two complementary techniques: Composite Agents and Right of Way. The former exploits the underlying collision avoidance mechanism to encode abstract factors and the latter modifies the optimization algorithm's constraint definition to enforce asymmetric coordination. PedVO further changes the optimization algorithm to more fully encode the agent's knowledge of its environment, allowing the agent to make more intelligent decisions, leading to a better utilization of space and improved flow. PedVO incorporates a new model, which works in conjunction with the local planning algorithm, to introduce a ubiquitous density-sensitive behavior observed in human crowds -- the so-called "fundamental diagram." We also provide a physically-plausible, interactive model for simulating walking motion to support the computed agent trajectories. We evaluate these techniques by simulating various scenarios, such as pedestrian experiments and a challenging real-world scenario: simulating the performance of the Tawaf, an aspect of the Muslim Hajj.Doctor of Philosoph

Sketching for Real-time Control of Crowd Simulations

Controlling the behaviour of a crowd simulation typically involves tuning of a system's parameters through trial and error, a time-consuming process relying on knowledge of a potentially complex parameter set. Numerous graphical control approaches have been proposed to allow the user to interact with a simulation intuitively. This research investigates the use of a real-time sketch-based approach for crowd simulation control. This is done by modifying the environment of the simulation. Users can create entrances/exits, barriers and flow lines in real-time on top of an environment. This process requires a data structure to represent the environment and navigate the crowd through it. Two alternatives are presented: grid and navigation mesh. A detailed comparison shows that the navigation mesh is a more scalable approach since it uses less memory, has a similar pathfinding time, and is a better structure to represent the environment than the grid. The thesis also presents extensions to the sketch-based approach in the form of novel control tools, including storyboards to define the journey of the crowd, a timeline interface to simulate events through the day, and a sketch-based group storyboard to link behaviours and paths to be followed by a group. These tools are used to create two complex scenarios to exemplify possible applications of the sketch-based approach. The work on timelines also raises a new problem for an approach that dynamically modifies an environment in real-time which is 'when does the crowd know about the change?' Some initial solutions to how this should be handled are presented. The sketch-based system is evaluated by comparing it to a validated commercial system called MassMotion. The comparison takes into account the plausibility of the simulation and usability of the user interface. A user study is carried out to evaluate the graphical user interface of both systems. Formal evaluation methods are used to make the comparison: the benchmark suite 'steersuite', an adapted version of the Keystroke-Level Model (KLM) and the System Usability Scale (SUS). The results show that the sketch-based approach is faster and easier to use than MassMotion, but with fewer control options. An implementation of the sketching interface in a Virtual Reality environment is also considered. However, when compared to the desktop interface using a proposed adaptation to KLM for VR, the results show that sketching in a VR environment is slower and less accurate than the desktop version

A Navigation Mesh for Dynamic Environments

Games and simulations frequently model scenarios where obstacles move, appear, and disappear in an environment. A city environment changes as new buildings and roads are constructed, and routes can become partially blocked by small obstacles many times in a typical day. This paper studies the effect of using local updates to repair only the affected regions of a navigation mesh in response to a change in the environment. The techniques are inspired by incremental methods for Voronoi diagrams. The main novelty of this paper is that we show how to maintain a 2D or 2.5D navigation mesh in an environment that contains dynamic polygonal obstacles. Experiments show that local updates are fast enough to permit real-time updates of the navigation mesh