The route design of the aircraft in electronic map must consider the restrictions and constraints of the geographical barriers. It needs to deal with the islands, and describe the islands as a series of discrete data ...
详细信息
ISBN:
(纸本)9781538608432
The route design of the aircraft in electronic map must consider the restrictions and constraints of the geographical barriers. It needs to deal with the islands, and describe the islands as a series of discrete data points. For the route planning, The data of dense points is so huge that it occupies too much machine time and the efficiency is very low. To overcome this shortcoming, an improved dp algorithm based on spatial memory and double threshold is proposed. Feature points are extracted under the premise of guaranteeing their geometric shape unchanged, and the geography information of the mission area is simplified. Then, according to the distance between the objects and the shape of the threshold value, the feature groups are combined to reduce the amount of geographic information and improve the operation efficiency. Finally, a special data file storage format is designed, and the processed geographic information is stored in the scale spectrum system, which is convenient for the screening and reading of obstacles. The simulation results verify the validity of the proposed method.
The maritime traffic status is monitored through the Automatic Identification System (AIS) installed on vessels. AIS data record the trajectory of each ship. However, due to the short sampling interval of AIS data, th...
详细信息
The maritime traffic status is monitored through the Automatic Identification System (AIS) installed on vessels. AIS data record the trajectory of each ship. However, due to the short sampling interval of AIS data, there is a significant amount of redundant data, which increases storage space and reduces data processing efficiency. To reduce the redundancy within AIS data, a compression algorithm is necessary to eliminate superfluous points. This paper presents an offline trajectory compression algorithm that leverages geospatial background knowledge. The algorithm employs an adaptive function to preserve points characterized by the highest positional errors and rates of water depth change. It segments trajectories according to their distance from the shoreline, applies varying water depth change rate thresholds depending on geographical location, and determines an optimal distance threshold using the average compression ratio score. To verify the effectiveness of the algorithm, this paper compares it with other algorithms. At the same compression ratio, the proposed algorithm reduces the average water depth error by approximately 99.1% compared to the Douglas-Peucker (dp) algorithm, while also addressing the common problem of compressed trajectories potentially intersecting with obstacles in traditional trajectory compression methods.
This study mainly analyses the fuel consumption of plug-in hybrid vehicles during operation. A new control method for automobiles based on energy management strategy and dynamic programming algorithm is proposed. The ...
详细信息
This study mainly analyses the fuel consumption of plug-in hybrid vehicles during operation. A new control method for automobiles based on energy management strategy and dynamic programming algorithm is proposed. The new method plans and analyses the minimum electricity consumption, and then uses dynamic programming algorithms to analyse this parameter. The research results indicated that the vehicle state was constantly changing with the variation of SOC value during driving. The energy mobilization of the vehicle was more obvious after adding dynamic programming strategy. The efficiency of the vehicle was relatively high in driving state 1, with a minimum value of 70%, which was about 20% higher than in driving state 4. The average fuel consumption in driving state 2 was 1.8L higher than in other driving states. The overall efficiency of automobiles after incorporating dynamic programming was improved, with a shorter time to reach the lowest efficiency point compared with not incorporating dynamic programming algorithms. The highest efficiency value was 7.86% higher than that of not incorporating dynamic programming models. The new control method can reduce energy consumption and improve the energy management and control effect. The study provides a better research direction for energy management and control of hybrid electric vehicles in the future.
In this article, an integrated "dual-motor automated mechanical transmission" configuration was proposed for battery electric vehicles, and a rule-based energy management strategy based on dynamic programmin...
详细信息
In this article, an integrated "dual-motor automated mechanical transmission" configuration was proposed for battery electric vehicles, and a rule-based energy management strategy based on dynamic programming ( dp) algorithm optimization was designed. The rule-based energy management strategy was used for online control, and the dp algorithm was used to optimize the control parameters of the rule-based energy management strategy offine. Finally, the optimization results were validated online using the hardware-in-the-loop simulation platform. The results showed that on average, the optimized rule-based energy management strategy can reduce energy consumption by 4.16% under the New European Driving Cycle, Urban Dynamometer Driving Schedule, and Japan 1015 cycle conditions. More importantly, there were evident energy-saving effects on the United States 06, China Light-Duty Vehicle Test Cycle-Passenger, and Highway Fuel Economy Test cycle conditions, which did not participate in the optimization of the rule-based energy management strategy by the dp algorithm.
Maritime traffic route extraction is essential for analyzing dynamic ship navigational information in vast sea areas. However, maritime traffic route extraction is still challenging due to the high frequency and freed...
详细信息
Maritime traffic route extraction is essential for analyzing dynamic ship navigational information in vast sea areas. However, maritime traffic route extraction is still challenging due to the high frequency and freedom of ship navigation. Thus, our study proposes a maritime traffic route extraction method based on automatic identification system (AIS) data and the multi-dimensional density-based spatial clustering of applications with noise (MD-DBSCAN) data. In the first part of the method, the Douglas-Peucker (dp) algorithm is used to compress massive ship trajectories, and a new indicator (the average compression score (ACS)) is used to determine the optimal compression threshold. In the second part, with the measure of similarity between ship trajectories by two similarity measure indicators, including the spatial distance and the difference of the course over ground (COG) of the key turning points of the ship trajectories, the ship trajectories are clustered by the MD-DBSCAN algorithm. In the third part, the centerlines of each cluster are extracted with the triangular network center method. Numerical experiments are conducted based on massive AIS data in the South China Sea. The experimental results show that our method dramatically influences the recognition of noise and normal trajec-tories and can effectively extract maritime traffic routes.
This study proposes an integrated eco-driving controller, in which speed profile and power split optimisation are simultaneously treated. A speed profile controller is designed based on a multi-phase dynamic programmi...
详细信息
This study proposes an integrated eco-driving controller, in which speed profile and power split optimisation are simultaneously treated. A speed profile controller is designed based on a multi-phase dynamic programming (dp) algorithm, which is utilised to optimise speed trajectories with the detailed model of the traction power system, vehicle dynamics system, and signal constraints at intersections. The optimised speed and demand power profiles are designed as the reference of the power split optimal controller. A dp algorithm is presented to determine voltage trajectories of supercapacitors with power plant voltage limitations and dynamic power losses. The performance of the proposed integrated method is evaluated by numerical simulation based on an actual route of Chengdu Tramway Line 2. The energy reduction can be achieved by the speed profiles controller, compared to the eco-cruising benchmark strategies. Energy efficiency can be further improved by the integrated eco-driving controller. Moreover, the influences of green signal time windows and trip time on the shape of the optimised solution are investigated. For a given journey, the trip time with minimum energy consumption can be obtained. The integrated eco-driving control method can be implemented by driver assistant systems or automatic train operation systems.
The deficiencies of massive data like storage difficulty, computation inefficiency, and information redundancy call for ship trajectory compression. While most studies on ship trajectory compression have one or more o...
详细信息
The deficiencies of massive data like storage difficulty, computation inefficiency, and information redundancy call for ship trajectory compression. While most studies on ship trajectory compression have one or more of the following drawbacks: the drawback of low compression efficiency;the problem resulted from error ship static information when the distance threshold is set based on ship length or width;poor compression quality for some trajectories, which is caused by experience-based optimal threshold. To solve these problems, we propose the Adp (Adaptive-threshold Douglas-Peucker) algorithm based on dp (Douglas-Peucker) algorithm. By determining the key points of each trajectory through the threshold change rate, Adp no longer relies on ship static information and makes it easier to determine the threshold, which is what traditional algorithms cannot achieve. Additionally, we use the advantage of matrix operation and the method of reducing points to improve the algorithm's computation efficiency. To verify the feasibility and superiority of the proposed algorithm, we compared our algorithm with dp algorithm, Partition-dp algorithm and Sliding Window algorithm from four aspects, namely, compression rate, Synchronous Euclidean distance, Length Loss Rate and running time. The experimental results prove that our algorithm has advantages over the other three algorithms, especially in threshold setting.
Big data and the curse of dimensionality are common vocabularies that researchers in different communities have recently been dealing with, e.g. dynamic programming (dp) in automatic control system society. A novel un...
详细信息
Big data and the curse of dimensionality are common vocabularies that researchers in different communities have recently been dealing with, e.g. dynamic programming (dp) in automatic control system society. A novel unweighted sampled based least square projection approach is proposed in this study to address the issue of the large state space in the dp optimisation problem. The method, in particular, takes into account both contraction mapping and monotonicity properties of the dp algorithm for value function approximation. Specifically, the batch of samples are gathered by uniform probability distribution at first, and an unweighted LS sub-problem in the subspace is solved. As the case study, a new Markov decision process model associated with a resource allocation problem is considered to illustrate the technique and evaluate its effectiveness. It is noted that the approach can be employed for different applications as well. Moreover, a MATLAB based software is developed to implement and examine different parts of the proposed method. Simulation examples are considered to support the results of the approach via developed software. The idea makes a connection between the recent advances in big data analysis and approximate dp as well.
This paper considers the design of short non-binary low-density parity-check (LdpC) codes over finite fields of order m, for channels with phase noise. In particular, m-ary differential phase-shift keying (dpSK)-modul...
详细信息
This paper considers the design of short non-binary low-density parity-check (LdpC) codes over finite fields of order m, for channels with phase noise. In particular, m-ary differential phase-shift keying (dpSK)-modulated code symbols are transmitted over an additive white Gaussian noise (AWGN) channel with the Wiener phase noise. At the receiver side, non-coherent detection takes place, with the help of a multi-symbol detection algorithm, followed by a non-binary decoding step. Both the detector and the decoder operate on a joint factor graph. As a benchmark, finite length bounds and information rate expressions are computed and compared with the codeword error rate (CER) performance, as well as the iterative threshold of the obtained codes. As a result, performance within 1.2 dB from finite-length bounds is obtained, down to a CER of 10(-3).
Due to the disadvantages of measuring the pavement structure by two-dimensional imaging techniques, a systematic method based on NURBS reconstruction for 3D structured light pavement topography is proposed. First, acc...
详细信息
Due to the disadvantages of measuring the pavement structure by two-dimensional imaging techniques, a systematic method based on NURBS reconstruction for 3D structured light pavement topography is proposed. First, according to the principle of triangulation and different extraction methods of the center of line structured light stripe, the discriminating basis of different types of pavement topography is given. The Douglas-Puke algorithm is selected to extract the feature points of the road contour. Then, the curve fitting based on feature points can be used as a description of the cross section of the pavement and gives the depth information after fitting. Finally, NURBS modeling method is chosen to reconstruct the contour and topography of the road surface. The experimental results show that, compared with the traditional manual measurement method, the proposed method improves the measurement accuracy by about 9%, which highlights the accuracy and efficiency of line structure photometry.
暂无评论