This study aims to find an experientially reliable path considering travel time uncertainty and driving experience of local probe vehicle drivers. Accordingly, a two-stage route-finding procedure is proposed. First, a...
详细信息
This study aims to find an experientially reliable path considering travel time uncertainty and driving experience of local probe vehicle drivers. Accordingly, a two-stage route-finding procedure is proposed. First, a set of candidate paths is built by using the hyperpathalgorithm, where the choice probability is assigned to each link with uncertain travel time. Second, the shortest path algorithm is applied to find the experientially reliable path on the graph of hyperpath where the modified link cost is penalised based on the link choice probability derived from hyperpathalgorithm and the driving experience of local drivers. Four kinds of optimal path in a real-world network are compared with the observed one. It is found that the proposed path has the most similarity with the observed path and it has a higher degree of familiarity and reasonable time and distance.
Purpose To solve the path planning problem of the intelligent driving vehicular, this paper designs a hybrid path planning algorithm based on optimized reinforcement learning (RL) and improved particle swarm optimizat...
详细信息
Purpose To solve the path planning problem of the intelligent driving vehicular, this paper designs a hybrid path planning algorithm based on optimized reinforcement learning (RL) and improved particle swarm optimization (PSO). Design/methodology/approach First, the authors optimized the hyper-parameters of RL to make it converge quickly and learn more efficiently. Then the authors designed a pre-set operation for PSO to reduce the calculation of invalid particles. Finally, the authors proposed a correction variable that can be obtained from the cumulative reward of RL;this revises the fitness of the individual optimal particle and global optimal position of PSO to achieve an efficient path planning result. The authors also designed a selection parameter system to help to select the optimal path. Findings Simulation analysis and experimental test results proved that the proposed algorithm has advantages in terms of practicability and efficiency. This research also foreshadows the research prospects of RL in path planning, which is also the authors' next research direction. Originality/value The authors designed a pre-set operation to reduce the participation of invalid particles in the calculation in PSO. And then, the authors designed a method to optimize hyper-parameters to improve learning efficiency of RL. And then they used RL trained PSO to plan path. The authors also proposed an optimal path evaluation system. This research also foreshadows the research prospects of RL in path planning, which is also the authors' next research direction.
A method is described to determine the effect on the ECG of a reduced propagation velocity within an ischemic zone. The method was designed to change the activation sequence throughout the ventricles interactively, i....
详细信息
A method is described to determine the effect on the ECG of a reduced propagation velocity within an ischemic zone. The method was designed to change the activation sequence throughout the ventricles interactively, i.e. with a response time in the order of a second. The timing of ventricular ischemic activation was computed by using the fastest route algorithm, based on locally reduced values of the propagation velocities derived from a standard, normal activation sequence. The effect of these local reductions of the velocities on the total activation sequence, as well as the changes in the electrocardiogram that these produce, are presented.
The apical four-chamber view echocardiogram collected by a transthoracic transducer can be used to evaluate the left ventricle volume. In the diastole, the left ventricle and left atrium become one chamber. In this ca...
详细信息
The apical four-chamber view echocardiogram collected by a transthoracic transducer can be used to evaluate the left ventricle volume. In the diastole, the left ventricle and left atrium become one chamber. In this case, the left ventricle and left atrium need to be separated using a "mitral annular line" so the volume of the left ventricle can be estimated. In this paper, a nearly automatic method for identifying the mitral annular lines from two-dimensional (2-D) + one-dimensional (1-D) precordial four-chamber view echocardiogram is presented. This method employs the optical flow technique and graph-search approach. The mitral annular line sequence is found by finding the shortestpath in a weighted directed graph. The vertices in the graph are candidates for the mitral annular lines. The weights on the directed edges are determined using the optical flow technique. The proposed method requires only a physician to provide, a point that is always in the left ventricular chamber. Experimental results show that the average error for the left ventricle volume obtained based on the computed mitral annular lines is 3%.
This paper deals with the problem of optimal dynamic routing in WDM optical networks with wavelength-changing facilities available at some of the nodes. The route may be either a lightpath (i.e., wavelength continuous...
详细信息
This paper deals with the problem of optimal dynamic routing in WDM optical networks with wavelength-changing facilities available at some of the nodes. The route may be either a lightpath (i.e., wavelength continuous channel) or a semi-lightpath (i.e., wavelength-converted channel). We attempt to estimate in this work the gain in blocking probability, when we move from lightpath routing to semi-lightpath routing, keeping the number of wavelengths fixed, in a given circuit switched network. We ensure optimal (minimum cost) routing in both the cases by using the algorithm of Banerjee et al. [7,8] (called algorithm-I in this paper) for lightpaths and that of Chlamtac et al. [6] (called algorithm-II) for semi-lightpaths. Our results indicate that, for both the algorithms, the blocking probability (P-B), as expected, increases with network load. At light load, P-B for algorithm-I is always larger than that for algorithm-II. But the rate of increase in P-B is slightly higher in case of algorithm-II, so that there is a crossover point where P-B for algorithm-II exceeds P-B for algorithm-I. This probably happens due to the irregularities in the semi-lightpaths at heavy loads when almost all routes are exhausted in the network. However, since this crossover phenomenon occurs at a very congested status of the network, it has little significance over the real life operation of a network. It only suffices to indicate that, under heavy load, both the algorithms are equally insufficient, and conversion does not improve the situation as might have been expected intuitively.
This paper introduces a graph-oriented representation of metabolism, and shows how to apply the shortest path algorithm to reconstruct metabolic pathways. Our metabolic model is constructed from molecular structures o...
详细信息
This paper introduces a graph-oriented representation of metabolism, and shows how to apply the shortest path algorithm to reconstruct metabolic pathways. Our metabolic model is constructed from molecular structures of compounds and reaction formulas of enzymes, and its output is all the logically possible pathways consisting of input reactions. We also show how to integrate putative reactions in the model. (C) 2000 Elsevier Science B.V. All rights reserved.
This paper presents an inter-vehicular communication IVC)-based algorithm for real-time route guidance in urban traffic networks. The algorithm enables communication between searcher vehicle and candidate-vehicles who...
详细信息
This paper presents an inter-vehicular communication IVC)-based algorithm for real-time route guidance in urban traffic networks. The algorithm enables communication between searcher vehicle and candidate-vehicles whose origin node matches the destination node of the searcher vehicle, and traveling in the opposite direction. The data entities of knowledge sharing among the vehicles and the algorithmic procedure as well as the conditions for information sharing are presented in detail. The mathematical formulation of the procedure is also presented. A microscopic simulation model is utilized to assess the effectiveness of the algorithm against the benchmark shortest path algorithm. Average travel time, and overall network productivity are presented to measure the effectiveness of the algorithm. Simulation runs are conducted under various network congestion levels, link speeds and link lengths in order to evaluate the network productivity, and the travel time measures of the presented IVC algorithm compared to the benchmark shortest path algorithm, decentralized route guidance systems as well as other IVC-based algorithms. (C) 2015 Elsevier Inc. All rights reserved.
In this paper, a novel nature-inspired optimization algorithm has been employed and the trained behaviour of dogs in detecting smell trails is adapted into computational agents for problem solving. The algorithm invol...
详细信息
Intelligent transportation system plays an important role in the field of logistics transportation, which can improve the efficiency of logistics transportation, reduce costs and reduce traffic congestion. Logistics t...
详细信息
ISBN:
(纸本)9781510674479
Intelligent transportation system plays an important role in the field of logistics transportation, which can improve the efficiency of logistics transportation, reduce costs and reduce traffic congestion. Logistics transportation planning and simulation is a key problem in the field of intelligent transportation. It can help logistics enterprises to carry out reasonable path planning and resource allocation, predict the possible problems in the transportation process in advance, and optimize the transportation scheme to improve the transportation efficiency. Based on the logistics and transportation planning and simulation in the field of intelligent transportation, this paper studies how to optimize the path selection, resource scheduling and transportation planning arrangement in the process of logistics and transportation through the modeling and simulation of the existing logistics and transportation system. The experimental results of this paper show that the logistics simulation system based on the field of intelligent transportation has advantages over the traditional logistics system in terms of transportation time, cost and safety indicators. Specifically, the average transportation time of this system is 8.5 hours, which is shorter than 10.5 hours of the traditional logistics system;the average cost is 4280 yuan, lower than 5000 yuan of the traditional logistics system, and the average safety index is 93.3%, which is higher than 88.5% of the traditional logistics system. It shows that the logistics simulation system based on the field of intelligent transportation has potential and feasibility in logistics transportation, which is expected to promote the development of logistics industry and improve the efficiency of logistics transportation.
With the development of car industry, the number of vehicles traveling on the roads is ever increasing, leading to traffic congestion problem which causes air pollution, driver frustration and meaningless fuel consump...
详细信息
ISBN:
(纸本)9781467396462
With the development of car industry, the number of vehicles traveling on the roads is ever increasing, leading to traffic congestion problem which causes air pollution, driver frustration and meaningless fuel consumption. Excellent navigation algorithm is urgently needed and some solutions have been put forward to tackle the problem. However, existing studies are mostly devised for static networks. They are not effective when they are applied in real dynamic environments. This paper presents an improved A* algorithm in dynamic urban traffic to give an optimal path in real-time traffic environment. This algorithm not only tackles the congestion problem, but also solves the problem more efficiently.
暂无评论