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Two-echelon location-routing model and algorithm for waste recycling considering obnoxious effect
MA Yanfang, ZHANG Wen, LI Zongmin, YAN Fang, GUO Lingyun
Journal of Computer Applications    2023, 43 (1): 289-298.   DOI: 10.11772/j.issn.1001-9081.2021111969
Abstract358)   HTML5)    PDF (3080KB)(132)       Save
With regard to the Location-Routing Problem (LRP) of domestic waste transfer stations and incineration stations, by considering the economic objective and the obnoxious effect of waste facilities, a piecewise function of obnoxious effect related to wind direction and distance was designed, a Two-Echelon Multi-Objective LRP (2E-MOLRP) model was formulated, and a non-dominated algorithm combining Whale Optimization Algorithm (WOA) and Simulated Annealing (SA) algorithm was proposed, namely WOA-SA. Firstly, the random method and Clarke and Wright (CW) saving algorithm were used to optimize the initial population. Secondly, a nonlinear dynamic inertia weight coefficient was adopted to adjust the convergence speed of the WOA-SA. Thirdly, the global optimization ability was enhanced by designing the parallel structure of WOA-SA. Finally, the Pareto solution set was obtained by using the non-dominated sorting method. The analysis was carried out on 35 benchmark cases such as Prins and Barreto as well as a simulated case of Tianjin. The results show that the WOA-SA can find the Best Known Solution (BKS) of 20 benchmark cases, and has the mean values of the difference between the solution results and the BKSs of 0.37% and 0.08% on Prins and Barreto cases, which proves the good convergence and stability of the WOA-SA. The proposed model and algorithm were applied to the instance, and provided three schemes with different obnoxious effect values and economic costs for decision makers with different decision preferences. Therefore, the cost of waste recycling and the obnoxious effect of facilities on environment were reduced.
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Algorithms for low-carbon pickup and delivery vehicle routing problem with fuzzy demand
MA Yanfang, WANG Shan, HUANG Lingyu, CHENG Cong
Journal of Computer Applications    2021, 41 (3): 851-859.   DOI: 10.11772/j.issn.1001-9081.2020071079
Abstract464)      PDF (1198KB)(684)       Save
Due to high carbon emissions in the logistics and distribution process, from a low carbon perspective, a Low Carbon Vehicle Routing Problem with Pickup and Delivery (LCVRPPD) considering fuzzy demand was formulated, and a 2-OPT based differential algorithm was proposed to solve the problem. In the algorithm, the natural number encoding method was adopted and three different fitness functions were given. Then, the 2-OPT algorithm was introduced to replace the original mutation mechanism of differential algorithm, and the binomial crossover operators and greedy selection operator were combined, so as to accelerate the convergence of the improved algorithm. In the case study, Taguchi method was used to determine reasonable values of parameters in the improved algorithm, and the SPSS (Statistical Product and Service Solutions) analysis revealed that the solution of the model with the minimum total cost as the objective function is the best compared to those of the other two different objective models of transportation cost minimization and carbon minimization respectively. For examples with different customer scales, compared with the basic differential algorithm, the improved algorithm has the total cost reduced by 1.8% to 3.0% and the carbon emission decreased by 0.7% to 3.5%; compared with genetic algorithm, the improved algorithm has the total cost reduced by 1.9% to 16.47% and the carbon emission decreased by 1.2% to 4.3%; compared with particle swarm optimization algorithm, the optimization effect is more obvious, the improved algorithm has the total cost reduced by 4.0% to 22.5% and the carbon emission decreased by 1.56% to 7.88%, which verify the effectiveness and advancement of the proposed algorithm. In summary, the proposed model and algorithm can provide a reference for the low carbon routing problem of pickup and delivery vehicles.
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Prediction of organic reaction based on gated graph convolutional neural network
LAI Zicheng, ZHANG Yuping, MA Yan
Journal of Computer Applications    2021, 41 (10): 3070-3074.   DOI: 10.11772/j.issn.1001-9081.2020111752
Abstract336)      PDF (1291KB)(444)       Save
Under the development of modern pharmaceutical and computer technologies, using artificial intelligence technology to accelerate drug development progress has become a research hotspot. And efficient prediction of organic reaction products is a key issue in drug retrosynthesis path planning. Concerning the problem of uneven distribution of chemical reaction types in the sample dataset, an Active Sampling-training Gated Graph Convolutional Neural-network (ASGGCN) model was proposed. Firstly, the SMILES (Simplified Molecular Input Line Entry Specification) codes of the chemical reactants were input into the model, and the location of the reaction center was predicted through Gated Graph Convolutional Neural-network (GGCN) and attention mechanism. Then, according to chemical constraint conditions and the candidate reaction centers, the possible chemical bond combinations were enumerated to generate candidate reaction products. After that, the gated graph convolutional difference network was used to rank the candidate products and obtain the final reaction product. Compared with the traditional graph convolutional network, the gated graph convolutional network has three weight parameter matrices and fuse the information through gating, so it can obtain more abundant atom hidden feature information. At the same time, the gated graph convolutional network is trained by active sampling, which can take into account both the analysis abilities of poor samples and ordinary samples. Experimental results show that the Top-1 prediction accuracy of the reaction product of the proposed model reaches 87.2%, which is increased by 1.6 percentage points compared to the accuracy of WLDN (Weisfeiler-Lehman Difference Network) model, illustrating that the organic reaction products can be predicted more accurately by the proposed model.
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Russian phonetic transcription system based on TensorFlow
FENG Wei, YI Mianzhu, MA Yanzhou
Journal of Computer Applications    2018, 38 (4): 971-977.   DOI: 10.11772/j.issn.1001-9081.2017092149
Abstract602)      PDF (1115KB)(658)       Save
Focusing on the limited pronunciation dictionary in Russian speech synthesis and speech recognition system, a Russian grapheme-to-phoneme algorithm based on Long Short-Term Memory (LSTM) sequence-to-sequence model was proposed, as well as a phonetic transcription system. Firstly, a new Russian phoneme set based on Speech Assessment Methods Phonetic Alphabet (SAMPA) was designed, making transcription results can reflect the stress position and vowel reduction of Russian words, and a 20 000-word Russian pronunciation dictionary was constructed according to the new phoneme set. Then, the proposed algorithm was implemented by using the TensorFlow framework, in which the Russian word was converted into a fixed-length vector by encoding LSTM, and then the vector was converted into the target pronunciation sequence by decoding LSTM. Finally, the Russian phonetic transcription system was designed and implemented. The experimental results on out-of-vocabulary test set show that the word correct rate reaches 74.8%, and the phoneme correct rate reaches 94.5%, which are higher than those of Phonetisaurus method. The system can effectively support the construction of the Russian pronunciation dictionary.
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Face recognition with adaptive local-Gabor features based on energy
ZHOU Lijian MA Yanyan SUN Jie
Journal of Computer Applications    2013, 33 (03): 700-703.   DOI: 10.3724/SP.J.1087.2013.00700
Abstract1123)      PDF (653KB)(586)       Save
Concerning the time-consuming and computational complexity in extracting face features of traditional Gabor filters, the face features were extracted by using three different local Gabor filters adaptively chosen by the Gabor images' energy from different directions, scales and overall situation. Firstly, the Gabor features of some images in the face database were extracted and analyzed, and the local Gabor filters were built by choosing the filters corresponding to the images with larger energy. And then, the Fisher features were extracted using Linear Discriminate Analysis (LDA) further. Finally, face recognition was realized using the nearest neighbor method. The experimental results based on ORL and YALE face database show that the proposed approach has better face recognition performance with less feature dimension and calculation time.
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Improved nonlinear random early detection algorithm
Jun MA Yan-ping ZHANG Yong-cheng WANG Xiao-yan CHEN
Journal of Computer Applications    2011, 31 (04): 890-892.   DOI: 10.3724/SP.J.1087.2011.00890
Abstract1527)      PDF (595KB)(479)       Save
Active queue management is a focus of current research. Random Early Detection (RED) is one kind of classical queue management algorithms. Linear RED is simple and easy to calculate; however, when average queue size is near to the minimum and maximum threshold, the loss rate is unreasonable. After verifying the nonlinear character between average queue size and packet loss rate, an improved RED algorithm named JRED was presented. The simulation on NS2 shows that the average throughput is improved, and the packet loss rate is decreased. With the JRED algorithm, the stableness and reliability of network are enhanced.
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Image retrieval based on IFS fractal code
MA Yan, LI Shun-bao
Journal of Computer Applications    2005, 25 (03): 594-595.   DOI: 10.3724/SP.J.1087.2005.0594
Abstract1118)      PDF (143KB)(1038)       Save

The technology of image retrieval on compression domain was researched. Each image in the database was compressed by fractal coding and IFS fractal code was got. Based on the fractal code, the distance of query image and the image in the database was calculated using the distribution character of fractal code. Experiment results show that the algorithm presented is efficient in image retrieval based on IFS code.

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