48 results about "Shortest path problem" patented technology

The invention discloses an optimization method of the shortest emergency logistics path based on the fish swarm ant colony algorithm. The congestion factor is introduced into the basic ant colony algorithm to solve the optimization problem of the shortest emergency logistics path and enhance the search for emergency logistics. The ability to optimize the best solution for the path reduces the possibility of the basic ant colony algorithm falling into a local optimum. (1) Input the number of ants, the maximum number of iterations and the maximum load capacity of the vehicle, select the emergency situation, and input the importance of residual pheromone, the importance of heuristic pheromone, evaporation coefficient and intensity coefficient; (2) Find the shortest emergency logistics route : (1) Establish the model of the shortest emergency logistics route optimization problem; (2) The solution process of the model; (3) Display the distribution route results and the performance comparison results of the algorithm in solving the shortest emergency logistics route optimization problem. The optimization scheme for finding emergency logistics routes in the present invention is more efficient.

A plurality of landmarks selected from a source weighed graph on which a path search is performed; and the shortest path lengths between landmarks, and the shortest path lengths from vertices to landmarks adjacent to the respective vertices are calculated, and are stored in a memory device so as to be later referable. Routines for calculating upper and lower limits of the shortest path length corresponding to two vertices v and w are prepared by using expressions derived from quadrangle inequalities formed of the two vertices v and w as well as two landmarks adjacent to the respective vertices v and w. In response to a call from an A* search program, these routines return the upper limit or the lower limit of the shortest path length corresponding to v and w by referring to the shortest path lengths between landmarks, and the shortest path lengths from vertices to landmarks adjacent to the respective vertices, which have been previously stored in the memory device.

The invention discloses a moving object destination prediction algorithm. The method comprises the steps that firstly, an improved track segmentation method with the minimum description length (IMDL)is provided, weight parameters are introduced, meanwhile, a Dijkstra algorithm is used for converting the track segmentation problem into the shortest path problem of an undirected graph, the optimalsegmentation of a track is obtained, and therefore the track is simplified; then, a deep learning prediction model EP-LSTM based on embedded processing and long-short-term memory fusion is provided, and a high-dimensional input vector is converted into an embedded vector to serve as input of the model. The method has the advantages that the problems of data sparseness and long-term dependence in moving object destination prediction are effectively solved, and an excellent prediction effect is achieved by performing a large number of experimental verifications on a real data set.

A method and system for calculating savings routes for display on a portable computing device (PCD) are described. The method includes receiving at least one of a product category and a service category from an operator of a PCD. The PCD may also receive a destination address. With this information, circle of influence data based on an offer for at least one product or service corresponding to the product category or service category may be generated and provided to the PCD. The circle of influence data may impact edge weights of a graph search algorithm. The graph search algorithm solves a single-source shortest path problem for a graph with non-negative edge path costs. The circles of influence in combination with the graph search algorithm allow a PCD to calculate one or more savings routes based on a start point and the desired destination address provided by the operator of the PCD.

The invention discloses an optimized layout method of road section traffic monitors. The method comprises the following steps: firstly, establishing a travel time error estimation model of vehicles ona road section L, and calculating travel time estimation errors of M vehicles on the road section L; establishing an optimized layout 0-1 integer programming model of road monitor and converting theoptimal monitor layout problem when the travel time estimation errors of M vehicles on the highway section L are minimum into the shortest path problem when the travel time estimation errors of the directed graph are minimum; and solving the shortest path when the travel time estimation error of the directed graph is minimum, wherein the node position corresponding to the shortest path is the optimal layout position of the monitor. According to the invention, on the premise that the number of the detectors is given, the optimal arrangement position of the traffic detectors can be optimally selected, the minimum estimation error of the whole journey time of the road section is ensured, the monitoring accuracy of the traffic monitor is improved, and the economical efficiency is very high.

The invention discloses an AGV access path optimization method based on an intelligent parking lot. An upper computer system quickly compares parking information of parking spaces and vehicles in the parking lot, and feeds back a detection signal to a main control computer; a parking space searching process is converted into a shortest path problem, and a heuristic A* algorithm is used for solving the problem. The main control computer can quickly obtain the optimal parking space through the A* algorithm and perform path planning, so that the time is shortened and the parking efficiency is improved. By means of grid map modeling, the visualization is better; the parking space utilization situation of the current parking lot and the position condition of an AGV can be checked in real time; and the monitoring and management of the parking lot are more convenient and intelligent.

The invention discloses a method for solving the shortest path problem based on an improved Q-learning algorithm. The method specifically comprises the following steps of: establishing a position-action value table, completely initializing the Q table to be 0, and selecting an appropriate updating step length, greedy parameters, reward discount and smooth parameters; setting an initial position tobe recorded as x0 and a target position to be recorded as xtf according to the requirement of the shortest path problem; The current position is marked as X, the initial position is assigned to the current position, and epson-is used for marking the current position as X; selecting an action according to a greedy method, and recording the action as A; Taking an action A at the X position, recording the obtained earnings r and the position X'transferred after the action A is taken, if X 'is equal to the target position xtf, assigning the initial position x0 to X, and otherwise assigning the X'to X; Updating the Q table; All positions adjacent to the position X are marked as X1, X2,..., Xn, and a Q table is updated; And repeating the above steps until the Q table converges. According to the invention, the existing Q-use at present is relieved; And the problem that the Q table convergence time is long when the problem of the shortest path is solved by the leader is solved.

The invention discloses a real-time path planning method based on an improved Kstar algorithm and deep learning. According to the real-time path planning method, a k-shortest paths problem is combined into real-time path planning, k excellent to-be-selected paths are quickly and efficiently found out by improving the Kstar algorithm, a more reasonable road evaluation formula is put forward, the time for passing through the road and the congestion index of the road are comprehensively considered, and the traffic pressure is relieved while the optimal path is found out. The improved Kstar algorithm is used for regionalizing a road map, the speed of heuristic search is greatly increased, efficient data structures such as heaps and path structure diagrams are constructed, unnecessary memory waste is optimized, a plurality of to-be-selected paths are quickly obtained under the condition that the time complexity of the method is close to that of a conventional optimal path algorithm, and the number of unnecessary navigation route planning times is effectively reduced.

The invention discloses a myxomycetes RRT navigation method and system based on two-dimensional static path planning, and the method comprises the steps: taking a point where a mobile robot is locatedas an original point, and taking a step length as a radius for making a circle; taking the circle as an exploration range, and taking points on the circle as a to-be-selected node set; when no obstacle exists in the exploration range, using the intersection point of the straight line connecting the starting point and the terminal point and the circle as a new node; making a circle by taking the node as an original point and the step length as a radius. According to the method, the new node is reselected, so that the obtained path is shortest. According to the method, the problems of unsmoothpath and non-shortest path of the RRT algorithm can be improved, so that the performance of the RRT algorithm is improved, and a better and shorter path is obtained.

The invention discloses a ship cabin noise transmission path analysis method, which comprises the steps of establishing a statistical energy analysis model according to a ship drawing; setting attributes of each subsystem in the statistical energy analysis model according to drawings and data; calculating an internal loss factor of each subsystem and a coupling loss factor between the subsystems,and establishing a loss factor matrix of the whole system; converting the loss factor matrix into a path efficiency matrix, and establishing a path efficiency weighting graph for noise transmission path analysis; and solving the first k shortest paths of the weighted graph by using an algorithm of the shortest path problem, so as to obtain the first k noise energy transfer paths from the noise source to the target cabin. The cabin noise transmission path analysis work can be completed at the initial stage of ship design, the limitation that real ship test analysis can only be conducted after aship is built is overcome, guidance can be provided for subsequent noise reduction design, and the cabin noise transmission path analysis method has the obvious effects of saving cost and reducing space and weight occupation.

The invention discloses a network anonymity method for modifying a graph structure based on optimal grouping of a degree sequence. The method comprises the following steps of: firstly, converting an optimal grouping problem of anonymity of a network node degree value sequence into a shortest path problem of a directed packet network; carrying out anonymity on a network node degree value sequence according to the shortest path of the directed packet network; modifying a network structure according to the anonymous information of the network node degree value sequence to realize anonymous operation of the network node degree value. The calculation amount in the network data anonymization process can be effectively reduced. The method is suitable for large-scale network data anonymization processing.

The invention relates to a path planning method and device passing through a necessary point set and having extra hard constraint, wherein the path planning method comprises the following steps: S1, a preprocessing stage: converting the actual application environment information into mathematical description, and completing the processing and modeling of an undirected weighted graph of a problem; and S2, a shortest path solving stage: carrying out shortest path solving by using a random search algorithm, carrying out real-time judgment on the feasibility of the path in the search process, solving the shortest path problem of the necessary point set under the condition of meeting the requirement of extra hard constraint, and finally obtaining the shortest path meeting the requirement. According to the method, the additional hard constraint can be added, and the calculation result meeting the engineering requirements under the actual physical limitation condition can be ensured to be obtained within the short calculation time.

The invention relates to a laser filling method and device for a multilayer contour pattern based on contour lines, computer equipment and a storage medium. The method comprises the following steps: performing outer contour inner offset operation on a to-be-filled pattern according to an equidistant offset algorithm to obtain a contour offset pattern; performing grid method environment modeling on the contour offset pattern to obtain a preprocessed grid pattern; performing inner and outer contour discrimination on the grid pattern to obtain a to-be-filled grid; for the to-be-filled grid, constructing a shortest path problem set; and solving the shortest path problem set by using an A* algorithm to obtain an optimal filling path of the to-be-filled grid. By adopting the method, the laser filling efficiency of the pattern can be improved.

The shortest path problem and the traffic N shortest path problem in the prior art consider a scene with determined travel time, but in a congested urban traffic network, the travel time has high uncertainty, and travelers tend to select paths with high reliability under the condition that the travel time is uncertain, so that the traffic efficiency is improved. According to the method, the shortest reliable path problem and the shortest reliable path expansion problem in the random traffic network are solved, and the shortest reliable path in the large GIS traffic network is efficiently searched by reducing the calculation scale of the shortest reliable path; for a general looped network, the first N shortest reliable paths are solved, the improvement advantages are obvious, firstly, the travel time determinacy limitation is few, the maneuverability is high, and flexibility and convenience are achieved; secondly, the first N shortest reliable paths are efficiently solved, and the reliability and availability of the shortest reliable paths are enhanced; and thirdly, the GIS network type is high in interactivity, high in precision and relatively low in algorithm complexity, and the development, popularization and application of the ITS and the ATIS are powerfully promoted.

The invention discloses an online service placement method with data refreshing based on value space estimation. The method comprises the following steps: in a mobile edge computing scene, under the condition that service background data is refreshed, determining how to select a service to be placed by an edge server, and adopting the manner to minimize a communication load between the edge server and a cloud server; converting a service placement problem into a shortest path problem; estimating a node value in the shortest path problem, and obtaining a service placement strategy of a next time slice during operation; finally, serving the user in the edge server so as to reduce the communication load between the edge server and the cloud server.

The invention discloses a constrained time-varying shortest path solving method based on a time wave delay neural network, and the method comprises the steps of solving a constrained time-varying shortest path problem(CTSPP for short) through the construction of a time wave delay neural network (TWDNN for short). The designed TWDNN is a novel neural network based on time wave delay neurons, the difference between the TWDNN and a traditional neural network is that the TWDNN does not need any training, and the design of the TWDNN comprises neuron structure design and neural network structure design. Each neuron on the time wave delay neural network is composed of an input part, a wave receiver part, a neuron state part, a wave generator part, a wave transmitter part and an output part. The wave is a medium for exchanging information among the neurons, the propagation delay of the wave among the neurons is equivalent to the transmission delay of a data packet on a network, and the output of the shortest path is based on the time wave received by the target neuron. Experimental results show that the method provided by the invention is superior to the existing method.

The invention discloses a shortest path generation method and a related device, and the method comprises the steps of simplifying a generation problem of a shortest path with a plurality of non-negative weight values of a sideband into a problem of a single non-negative weight value of the sideband; sequentially screening the K candidate paths by using other non-negative weight values of each edgein the directed graph to obtain K final paths, thereby solving the problem of multiple non-negative weight values of a sideband; according to the method, the shortest path problem of a single non-negative weight value of a sideband is restored to the shortest path problem of a plurality of non-negative weight values of the sideband through an incremental screening algorithm, virtual nodes do notneed to be introduced in the process, the problem that the scale of a graph is huge after the virtual nodes are introduced is avoided, and the purposes of reducing time complexity and improving timeliness are achieved.