Study on Near-Optimal Path Finding Strategies in a Road Network

Unmanned aerial vehicles (UAVs) are used in team for detecting targets and keeping them in its sensor range. There are various algorithms available for searching and monitoring targets. The complexity of the search algorithm increases if the number of nodes is increased. This paper focuses on multi UAVs path planning and Path Finding algorithms. Number of Path Finding and Search algorithms was applied to various environments, and their performance compared. The number of searches and also the computation time increases as the number of nodes increases. The various algorithms studied are Dijkstra's algorithm, Bellman Ford's algorithm, Floyd-Warshall's algorithm and the AStar algorithm. These search algorithms were compared. The results show that the AStar algorithm performed better than the other search algorithms. These path finding algorithms were compared so that a path for communication can be established and monitored.

In game Industry, the most trending research area is shortest path finding. There are many video games are present who are facing the problem of path finding and there is various algorithms are present to solve this problem. In this paper brief introduction is given in the most using algorithm for path finding and A* algorithm has been proved the best algorithm for resolving the problem of shortest path finding in games. It provides the optimal solution for path finding as compare to other search algorithm. At the start of the paper, brief introduction about the path finding is given. Then the reviews of different search algorithm are presented on the basis of path finding. After that information of A* algorithm and optimization techniques are described. In the last, application and examples how the path finding techniques are used in the game is addressed and future work and conclusion are drawn.

In 2004, Botea et al. published the HPA* algorithm (Hierarchical Pathfinding A*), which is the first detailed study of hierarchical pathfinding in games. However, HPA* can be optimized. In this paper, we introduce the DHPA* and SHPA* hierarchical pathfinding algorithms, along with a metric for comparing the dynamic performance of pathfinding algorithms in games. We show that DHPA* searches up to an order of magnitude faster than HPA*, but consumes significantly more memory and produces slightly less optimal paths. The SHPA* algorithm searches up to five times faster than HPA* and consumes less memory, but it also produces slightly less optimal paths, and is only fit for static environments. When comparing the algorithms in dynamic environments, our results show that DHPA* often outperforms HPA*. Unlike many other hierarchical pathfinding algorithms, both solutions presented in this paper maintain a read-only terrain representation during search, which simplifies programming and debugging, and improves multithreaded performance.

An energy-efficient reliable path finding algorithm for stochastic road networks with electric vehicles

Warehouse robots have been widely used by manufacturers and online retailer to automate good delivery process. One of the fundamental components when designing a warehouse robot is path finding algorithm. In the past, many path finding algorithms had been proposed to identify the optimal path and improve the efficiency in different conditions. For example, A* path finding algorithm is developed to obtain the shortest path, while D* obtains a complete coverage path from source to destination. Although these algorithms improved the efficiency in path finding, dynamic obstacle that may exist in warehouse environment was not considered. This paper presents AD* algorithm, a path finding algorithm that works in dynamic environment for warehouse robot. AD* algorithm is able to detect not only static obstacle but also dynamic obstacles while operating in warehouse environment. In dynamic obstacle path prediction, image of the warehouse environment is processed to identify and track obstacles in the path. The image is pre-processed using perspective transformation, dilation and erosion. Once obstacle has been identified using background subtraction, the server will track and predict future path of the dynamic object to avoid the obstacle.

Graph-based approaches for simulating pedestrian dynamics in building models

Many factors influence the connection states between nodes of wireless sensor networks, such as physical distance, and the network load, making the network’s edge length dynamic in abundant scenarios. This dynamic property makes the network essentially form a graph with stochastic edge lengths. In this paper, we study the stochastic shortest path problem on a directional graph with stochastic edge lengths, using reinforcement learning algorithms. we regard each edge length as a random variable following unknown probability distribution and aim to find the stochastic shortest path on this stochastic graph. We evaluate the performance of path-finding algorithms using regret, which represents the cumulative reward difference between the practical path-finding algorithm and the optimal strategy that chooses the global stochastic shortest path every time. We model the path-finding procedure as a Markov decision process and propose two online path-finding algorithms: Q SSP algorithm and SARSA SSP algorithm, both combined with specifically-devised average reward mechanism. We justify the convergence property and correctness of the proposed algorithms theoretically. Experiments conducted on two benchmark graphs illustrate the superior performance of the proposed Q SSP algorithm which outperforms the SARSA SSP algorithm and other competitive algorithms about the regret metric.

Geographic information systems related to the position of objects in the earth's surface such as the position of the attractions that are connected with roads. Streets that are interconnected to form a complex network. Usually people use our manual to find the shortest route of an object toward a particular object but it is less than optimal because it requires precision and a long time. The shortest route search problem has been solved by several algorithms such as Dijkstra's algorithm, Astar, Floyd Warshall, Ant Colony and others. Based on this final task is to discuss the implementation of the shortest route to the geographic information system of tourism in a city using the distance parameter. City to be addressed is Sawahlunto has 12 attractions that are connected with road network. Shortest path search algorithm used is Dijkstra's and Astar algorithm. Geographic information system of tourism is displayed in a web form, with the programming language PHP, database PosgreSQL and support PostGIS and pgRouting. Based on the testing of these applications can provide the shortest route along the travel distance to and from 12 tourist sites in Sawahlunto. Astar algorithm is faster in the process of finding the shortest route instead of Dijkstra's algorithm with an average gap of 40 ms. Application also provides information supporting the tourism profile information, attractions, culture, and contacts. Keyword : shortest path, Dijkstra algorithm, Astar algorithm, geographic information system

The main task in ensuring the appropriate level of organization of traffic on the street and road network of cities is to minimize traffic delays, increase traffic safety, provide transport and pedestrian communication between the planning elements of the city. Problems caused by the deterioration of the street and road network significantly affect the work of the entire transport complex of the city. Significant traffic delays, congestion, characterized by increased travel time, deterioration of transport services, increased pollution of urban environment due to increased emissions and noise, increasing the number of road accidents indicate the inconsistency of the road network of cities to the modern level of motorization. To ensure the required capacity of the elements of the road network, there is a need to create appropriate road conditions, namely the construction of new and reconstruction of existing engineering structures and elements of streets and roads. However, addressing these issues may not always improve the performance of the entire network, as, in parallel with technical measures based on the construction and reconstruction of transport infrastructure, the application of effective traffic management measures to manage traffic in urban areas should be addressed streets. When creating conditions for optimizing the operation of regulated intersections, it is necessary to take into account the technical condition of vehicles, road conditions and the condition of the road surface. One of the main tasks of any traffic organization is to increase the capacity of intersections and reduce vehicle delays, ie the passage of traffic lights with minimal delay. To solve the problem of congestion of the street and road network of the city is to increase the efficiency and use of coordinated management of traffic and pedestrian flows, improving the operation of traffic lights. To implement the introduction of coordinated traffic light regulation, or the so-called green wave, it is necessary to establish the intensity and composition of traffic flows, the capacity of the elements of the road network and the modes of operation of traffic light facilities. The paper considers the results of the study of the impact of coordinated traffic management in the central part of Rivne on reducing traffic delays when passing intersections by vehicles and proposed technical solutions to improve road safety by equipping intersections with additional technical means of traffic control.

This paper takes the urban road network as the research object to study the temporal and spatial characteristics and evolution mechanism of incidental traffic congestion. Firstly, the improved cell transmission model (CTM) is proposed considering the traffic flow delay phenomenon and the boundary conditions of the cell at the intersection. Secondly, considering the delay time of vehicles at the intersection, the A * path-finding algorithm is proposed, and a dynamic path selection model based on real-time road impedance is established. Finally, combined with the improved CTM and dynamic path selection model, starting from the severity of the incident and the frequency of information induction and update, the traffic flow is simulated by MATLAB software to simulate the traffic flow in the road network under different conditions and analyze the diffusion characteristics of congestion under sudden events. The simulation results show that during the simulation time period, when the traffic capacity caused by the severity of the incident is only 1/2, 1/4 and 1/8 of the original, the maximum number of congestion cells in the network is 9, 26 and 35, and the maximum delay per unit time stepping is 290, 1.31*103 and 2.41*103 vehicles, and the total delay in the road network is 2.73*105, 7.19*105, and 1.50*106 vehicles, after 320δ, 578δ and 588δ the congestion cells in the road network completely disappear. At the information induced update time of 30s, 120s and 600s, the maximum number of congestion cells in the road network is 5, 10 and 23, the maximum number of delayed vehicles is 162, 254 and 985 vehicles - time stepping, the total delay is 1.25*105, 1.68*105 and 5.84*105 vehicles. The findings of the study can provide reference for urban road network design and traffic management.

The actual state and quality of road transport operations largely depend on the efficiency of city transport on the road network. The economic development of cities, the level of comfort and living conditions of people in the settlements of the country hinge on the quality indicators of its operation. Since the level of efficiency of the city's road network heavily depends on the effectiveness of points of maximum concentration of traffic – transport and planning nodes, special attention should be paid specifically to these elements of the city's road network. In this regard, the analysis and research of energy consumption of the traffic flow as one of the criteria for assessing the choice of engineering solutions for transport and planning nodes is an actual direction for further scientific research. At the same time, the optimization of their planning decisions is considered only as one of the components in the system approach to minimizing the transport energy costs both in the road network of cities and in the transport sector of Ukraine as a whole.This paper considers the energy estimation as one of the criteria for justifying the choice of the engineering solution for the intersection of city highways by the example of a transport and planning hub at the intersection of the Kiltseva Doroga – Prospekt Peremohy – Prospekt Academika Palladina in Kyiv. To carry out the relevant assessment, a model is used to estimate the impact of energy consumption of the transport stream on the rationale for choosing an engineering and planning solution for intersecting city highways, taking into account the influence of individual design parameters characterizing the choice of their planning decisions, as compared to the model for determining the transport energy consumption with the help of the simulation tool, PTV Vissim software application.

The article considers issues aimed at improving conditions and traffic safety of street and road networks in cities and the possibility of using the functional classification of streets and roads. The development of cities is inextricably linked to the improvement of street and road networks. It is the street-road network that is the chain that connects it with the general ways of communication. The city cannot exist without public roads that provide a large amount of transportation, cargo and passengers, which are distributed among the functional zones of the city. The current regulatory document provides for the distribution of streets and roads, according to the classification into categories, but, unfortunately, their functional component is missing. In Ukraine, works related to the introduction of changes to the regulatory document are underway and are aimed at developing the functional purpose of streets and roads. The norms of the «Committee on Urban Territories», which belongs to the world-famous road association «PIARS» and the work of the special project «ARTISTS», are defined in the European classification. Attention should be paid to the significant variety of features in the European classification. It should be noted that in the USA and Canada, the functional classification provides for the functions of the specified road, and the main feature is «traffic service – access service». The US uses classifications based on the administrative level of the state, subject to the Department of Transportation "DOT" with mandatory consideration of the requirements of counties and municipal agencies. Great importance is attached to the requirements of the «Green book» – a green book belonging to the American Association of Highway and Transportation Officials (AASHTO). Canada also has its own distinctions for the preparation of functional classifications, which are based on the «Manual on geometric standards for the design of Canadian roads». They share similar features with the US in terms of defining three categories of streets, namely: Arterial Streets, Collector Streets and Local Streets. Also attracting attention are developments according to pedestrian traffic and low-white population groups. No less interesting are the features of the planning infrastructure in Western Australia. A comfortable environment is declared the official urban planning policy of the State Planning Commission of Western Australia (Western Australian Planning Commission). The concepts of creating a «livable environment» and «livable streets» were considered. In order to create a comfortable environment for living, attractive public spaces, preservation of the environment, the reasons for the concept were also economic factors. The main tasks of designing street and road networks, as well as directions and measures for their solution, are taken into account in the PIARC applications on the functional classification of city streets and roads. These recommendations systematize and summarize the classifications used by many countries in the process of designing street and road networks. Special attention is paid to main arterial streets, as well as architectural, landscape and urban design, safety and organization of traffic and pedestrian traffic. Keywords: street and road network, traffic safety, functional classification, pedestrian flows, project solutions.

One of the technologies in the industrial world that utilizes robots is the delivery of goods in warehouses, especially in the goods distribution process. This is very useful, especially in terms of resource efficiency and reducing human error. The existing system in this process usually uses the line follower concept on the robot's path with a camera sensor to determine the destination location. If the line and destination are not detected by the sensor or camera, the robot's navigation system will experience an error. it can happen if the sensor is dirty or the track is faded. The aim of this research is to develop a robot navigation system for efficient goods delivery in warehouses by integrating odometry and Dijkstra's algorithm for path planning. Holonomic robot is a robot that moves freely without changing direction to produce motion with high mobility. Dijkstra's algorithm is added to the holonomic robot to obtain the fastest trajectory. by calculating the distance of the node that has not been passed from the initial position, if in the calculation the algorithm finds a shorter distance it will be stored as a new route replacing the previously recorded route. the distance traversed by the djikstra algorithm is 780 mm while a distance of 1100 mm obtains the other routes. The time for using the Djikstra method is proven to be 5.3 seconds faster than the track without the Djikstra method with the same speed. Uneven track terrain can result in a shift in the robot's position so that it can affect the travel data. The conclusion is that odometry and Dijkstra's algorithm as a planning system and finding the shortest path are very efficient for warehouse robots to deliver goods than ordinary line followers without Dijkstra, both in terms of distance and travel time.

The primary objective of this study is to analyze the national and provincial road network in the city of Constantine, employing a range of quantitative methods commonly used in transportation geography. The aim is to assess the current state of the city's road network, its adequacy, efficiency, and suitability in meeting the needs of the population. This evaluation will be conducted in terms of accessibility, connectivity between network components, and efficiency as measured by curvature and traffic volume. While transportation geography offers a variety of quantitative measurement techniques, this research will focus on four primary methods: (1) Network analysis based on the curvature index: This method will assess the efficiency of the road network by evaluating the degree of curvature of the road segments, (2) Network analysis based on daily traffic volume: This method will examine the capacity of the road network by measuring the volume of traffic on each road segment, (3) Network analysis based on connectivity and road dispersion: This method will assess the level of connectivity between different parts of the network and the overall distribution of roads within the study area, (4) Network analysis based on traffic volume density: This method will evaluate the concentration of traffic on the road network.

Assessment of pore characteristics in virtual concrete by path planning methodology