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    Lightweight face super-resolution network based on asymmetric U-pyramid reconstruction
    Tongyu JIANG,Fan CHEN,Hongjie HE
    Journal of Shandong University(Engineering Science)    2022, 52 (1): 1-8, 18.   DOI: 10.6040/j.issn.1672-3961.0.2021.312
    Abstract395)   HTML11)    PDF(pc) (9804KB)(206)       Save

    A lightweight face super-resolution network was proposed in order to solve the problem that the model of deep convolutional neural network was complicated and difficult to be applied in the face super-resolution task. The coder composed of rescoding blocks was used for feature extraction, and pyramid reconstruction was introduced into the decoder to achieve fast and accurate super-resolution. To reduce the parameter number of the up-sampling operation in the decoding block, a non-uniform channel widening strategy based on resolution selection was adopted. To avoid adding extra branches, the prior knowledge of the face was introduced through heatmap loss. Experimental results showed that the model proposed in this paper could achieve light and accurate super-resolution reconstruction of ultra-low resolution face images that achieved better visual quality than the state-of-the-art method with lower model complexity.

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    Survey on student academic performance prediction from the perspective of task granularity
    Xiushan NIE,Yuling MA,Huiyan QIAO,Jie GUO,Chaoran CUI,Zhiyun YU,Xingbo LIU,Yilong YIN
    Journal of Shandong University(Engineering Science)    2022, 52 (2): 1-14.   DOI: 10.6040/j.issn.1672-3961.0.2021.489
    Abstract350)   HTML26)    PDF(pc) (1393KB)(149)       Save

    As one of the important research branches in educational data mining domain, student performance prediction was intensively studied. However, a comprehensive review of student performance prediction was still underexplored from the perspective of real applications. This paper detailed the technologies and methods exploited in student performance prediction research from the perspective of task granularity, and then introduced several application-oriented cases of student performance prediction, so as to provide targeted reference information for scientific researchers and educators.

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    Research progress of building structure under typhoon
    Li TIAN,Laiyi ZHANG,Yanming WANG,Juncai LIU
    Journal of Shandong University(Engineering Science)    2022, 52 (1): 28-38.   DOI: 10.6040/j.issn.1672-3961.0.2020.406
    Abstract340)   HTML7)    PDF(pc) (1920KB)(56)       Save

    Through the wind field simulation, field measurement, wind tunnel test, and the wind-induced vibration of structure under the effect of the domestic and foreign typhoon, the research progresses of four aspects were discussed. This article focused on the great influence people's production and life of all kinds of building structure, based on the structure under the action of typhoon research present situation and the existing problems. The problems that needed to be further studied under the influence of typhoon were prospected.

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    Method for generation planning with the temporal and spatial correlation of wind and solar power
    Wensheng LI,Xian WANG,Yuanze MI,Yongji CAO,Xiaoming LIU,Hengxu ZHANG,Zihan LIU
    Journal of Shandong University(Engineering Science)    2022, 52 (1): 111-119, 127.   DOI: 10.6040/j.issn.1672-3961.0.2020.424
    Abstract337)   HTML8)    PDF(pc) (4265KB)(42)       Save

    A generation planning method considering multi-dimensional spatial-temporal correlation of wind and solar energy was proposed. Based on Copula theory and probability distribution of wind power and photovoltaic, a wind power and photovoltaic output model considering multi-dimensional spatial-temporal correlation of wind power and photovoltaic was established. The output scenario was applied to the bi-level generation planning model, and a generation planning method considering the multi-dimensional spatial-temporal correlation of wind power and photovoltaic was proposed. Among them, the upper level was the investment decision-making model with the minimum total planning cost as the objective function, and the lower level was the short-term operation optimization model with the optimal operation economy and peak shaving characteristics as the objective. The effectiveness of the proposed method was verified by a case study in a certain area, and the influence of the spatial-temporal correlation of wind power and photovoltaic on the generation planning scheme was compared and analyzed.

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    Review and prospect of research on power system inertia with high penetration of renewable energy source
    Hengxu ZHANG,Zhimin GAO,Yongji CAO,Hao QIN,Dong YANG,Huan MA
    Journal of Shandong University(Engineering Science)    2022, 52 (5): 1-13.   DOI: 10.6040/j.issn.1672-3961.0.2022.237
    Abstract271)   HTML25)    PDF(pc) (4575KB)(171)       Save

    With the aim of carbon peak and carbon neutrality, the integration of high-proportion renewable energy sources (RESs) makes the low-inertia characteristic of the new power system more obvious. In order to ensure power system security and stability, and support the integration of RESs, the research on the power system inertia was reviewed and prospected. The essence of the power system inertia was introduced, and the correlation among the conventional inertia, virtual inertia and equivalent inertia was discussed, on which the physical significance of the virtual inertia was revealed. From the viewpoints of the sources of inertia, the research on the virtual inertia control of the wind machine, photovoltaic generation, and energy storage system was summarized. Additionally, the assessment methods of power system inertia were reviewed. The important issues to be focused in the research area of power system inertia were summarized, and the suggestions for further studies were provided.

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    Research progress on preparation methods of engineering nano material particle aerosol
    Hui HU, Ningye TANG, Siyu WANG, Haisen WANG
    Journal of Shandong University(Engineering Science)    2022, 52 (4): 1-11.   DOI: 10.6040/j.issn.1672-3961.0.2022.009
    Abstract231)   HTML28)    PDF(pc) (3186KB)(105)       Save

    With the development of nanotechnology and biochemistry, higher requirements were put forward for the particle size and manufacturing process of micro particles. Aerosol, as a common engineering nano material particle, was widely used in all walks of life. The research progress of common aerosol preparation methods, which starts from the aerosol preparation methods and systematically based on a large number of relevant literatures, the applicable scenarios of different aerosol preparation methods, the application requirements were summarized of different aerosol preparation methods were defined, the advantages and disadvantages of were compared and analyzed different aerosol preparation methods. On this basis, the optimization and improvement of various methods by domestic and foreign scholars in different periods were further ummarized, and the experimental and research results of domestic and foreign scholars were deeply analyzed, and the application of supercritical fluid technology in aerosol preparation was analyzed and prospected.

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    Preparation method and system of engineering nanoparticle aerosol
    Yi HAN,Zhen XU,Tian GUAN,Yang CUI,Hui HU,Liming MA
    Journal of Shandong University(Engineering Science)    2022, 52 (3): 109-116.   DOI: 10.6040/j.issn.1672-3961.0.2022.004
    Abstract215)   HTML4)    PDF(pc) (7468KB)(23)       Save

    A carbon nanoparticle aerosol preparation system with adjustable flow rate and mass concentration was designed based on the atomization method of nanomaterial suspension. The clean air and carbon nanotube material dispersion were sprayed and mixed in a stainless steel atomizing chamber to obtain an unstable aerosol. With the embedded temperature control system, flow control system and mass concentration control system, the unstable aerosol could be heated at a constant temperature in expansion chamber. Then the unstable aerosol expanded rapidly and reached uniformity. A relatively stable and uniform nanoparticle aerosol flow was obtained by controlling the valve body with an adjustable opening. It was demonstrated by experiments that under the condition of ideal temperature control system, the maximum error between the flow rate and the set value was 9.312 mL/min, and the maximum error between the mass concentration and the set value was 0.206 mg/m3. Nanoparticle aerosol with stable flow and mass concentration was generated basically.

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    Recognition learning based on multivariate functional principal component representation
    Yinfeng MENG,Qingfang LI
    Journal of Shandong University(Engineering Science)    2022, 52 (3): 1-8.   DOI: 10.6040/j.issn.1672-3961.0.2021.314
    Abstract212)   HTML6)    PDF(pc) (6668KB)(123)       Save

    Aiming at the problem of multi-dimensional information fusion in recognition learning, a recognition method based on multivariate functional principal component representation was proposed. The numerical calculation method of multivariate functional principal components was given. The joint covariance operator was used to calculate eigenvalues and eigenvectors, and the key distinguishing features were extracted. Based on these comprehensive features, the random forest method was used to recognize and learn multivariate functional data. The recognition performance of multivariate functional principal component representation method was compared with other representation methods on simulated data and real data. The experimental results showed that the accuracy was equal to 1 in the simulation dataset, English handwritten dataset and Chinese handwritten dataset, and 0.954 4 in the motion dataset. Compared with other methods, multivariate functional principal component analysis (MFPCA) had better recognition effect and improved the recognition accuracy effectively.

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    A machine vision system for measuring screw pitch with image processing techniques
    Tianyu HAN,Changhou LU,Jianmei LI,Ang YIN,Qiulin HOU
    Journal of Shandong University(Engineering Science)    2022, 52 (3): 80-85.   DOI: 10.6040/j.issn.1672-3961.0.2020.509
    Abstract211)   HTML7)    PDF(pc) (6708KB)(28)       Save

    In order to solve problems of damage to workpiece and high-cost of measuring equipment by contact measuring method, a low-cost and high-precision screw pitch measuring system based on machine vision was designed. The system was built on MATLAB and consisted of four sub-systems: image acquisition system, mechanical system, stepping control system, image and data processing system. Sub-pixel mosaic algorithm was used to splice the sub-images of the lead screw and a complete lead screw image could be obtained. Image quality was improved by image enhancement and filtering. Morphological edge extraction and sub-pixel edge location algorithm were used to extract the screw edge accurately, and pitch errors were measured automatically by data processing program. The experimental results showed that the relative error of the machine vision system and standard instrument (JCS-040A) for the measurement results of the three types of ball screw pitches didn't exceed 0.04%、0.06%、0.09%, respectively. The feasibility of the system in industrial measurement of lead screw was validated.

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    Shear capacity of beams with cracks and without web reinforcement
    Wenjie LIU,Xueying YANG,Bo ZHANG,Zhixin FAN,Chengxin LI,Huiming YANG,Jinglong LI
    Journal of Shandong University(Engineering Science)    2022, 52 (3): 42-50.   DOI: 10.6040/j.issn.1672-3961.0.2021.004
    Abstract202)   HTML6)    PDF(pc) (10009KB)(38)       Save

    In order to investigate the effect of the position and angle of the pre-existing cracks on the shear capacity of beams without web reinforcement, a number of experiment beams with pre-existing cracks were fabricated, the three-point bending experiment of the beam was carried out. The influence of pre-existing cracks located in the basic arch of the beam span and the beam side on the shear capacity of beams without web reinforcement and the law of crack propagation were studied. The results showed that the pre-existing cracks on the beam had a weakening effect on the shear capacity of the beam, which made the beam more prone to diagonal tensile failure. Under the same conditions, when the crack tip of the pre-existing crack in the beam span was closer to the middle point of the bottom of the beam, the greater the weakening effect on the shear bearing capacity of the beam without web reinforcement. When the coincidence degree of the angle of the pre-existing cracks on the beam side and the basic arch was higher, the greater the weakening effect on the shear bearing capacity of the beam without web reinforcement, and the cracks at the bottom of the beam propagate through the two crack tips of the pre-existing cracks was easier. Conversely, the cracks at the bottom of the beam could extend to the middle of the pre-existing cracks.

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    Theoretical study on synergistic dispatch for development of new power system
    HAN Xueshan, LI Keqiang
    Journal of Shandong University(Engineering Science)    2022, 52 (5): 14-23.   DOI: 10.6040/j.issn.1672-3961.0.2022.267
    Abstract166)      PDF(pc) (879KB)(47)       Save
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    Pre-allocation of resources based on trajectory prediction in heterogeneous networks
    Xiaobin XU,Qi WANG,Bin GAO,Zhiyu SUN,Zhongjun LIANG,Shangguang WANG
    Journal of Shandong University(Engineering Science)    2022, 52 (4): 12-19.   DOI: 10.6040/j.issn.1672-3961.0.2021.547
    Abstract155)   HTML27)    PDF(pc) (3698KB)(78)       Save

    Aiming at the problems of insufficient trajectory feature learning, low precision of trajectory prediction results, and coarse particles in the research of network resource management methods for trajectory prediction, a trajectory prediction algorithm of bidirectional recurrent neural network was proposed. Through in-depth mining of the user′s movement rules, the user′s movement prediction was realized. According to the user′s mobile prediction information, the network resource pre-allocation plan was designed and the mobile behavior was divided into network resources, then the collaborative resource optimization management of multiple cells was realized. The simulation results showed that in the trajectory prediction problem, the trajectory prediction algorithm of the bidirectional recurrent neural networked had better comprehensive performance than the ordinary neural network algorithm. In the problem of network resource management, the network resource management pre-allocation scheme of trajectory prediction could accurately predict the base station connected by users, so that the base station had a higher resource utilization rate.

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    Research and optimization of hollow form of precast concrete pavement slab
    Xuhao WANG,Qianqian LIU,Hucheng LI,cheng LI,Peng LI,Yifeng LING
    Journal of Shandong University(Engineering Science)    2022, 52 (4): 139-150.   DOI: 10.6040/j.issn.1672-3961.0.2022.046
    Abstract143)   HTML3)    PDF(pc) (7509KB)(27)       Save

    In order to reduce the self-weight of precast concrete pavement slab, the concrete hollow slab was studied by using ABAQUS, the optimal length, width and thickness and circular hollow type of precast concrete solid slab were recommended. The local sizes of the circular section were optimized, and the influences of the radius, numbers and height of circle on the maximum flexural-stress, the maximum vertical displacement, the maximum compressive stress and shear stress of the slab were analyzed. Entropy weight method and technique for order preference by similarity to an ideal solution method were introduced to optimize multiple parameters, and the optimal hollow combination was obtained as 10 circles with a radius of 60 mm and a center height of 160 mm. By comparing the mechanical performance of hollow slab with solid slab, it was found that the difference was marginal, while optimized hollow slab could lead to a 970 kg self-weight reduction. The precast concrete hollow slab, the circular hollow type and its local size were proposed and recommended.

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    Mechanical characteristics of TBM tunnel segment in composite stratum
    Weiqin ZHENG,Jie XU,Jie SUN,Ke WU
    Journal of Shandong University(Engineering Science)    2022, 52 (4): 210-213.   DOI: 10.6040/j.issn.1672-3961.0.2021.259
    Abstract139)   HTML3)    PDF(pc) (4433KB)(33)       Save

    Based on the redistribution of soil stress around the excavated tunnel due to the large buried depth of the tunnel during the construction of the composite stratum by the full section hard rock tunnel boring machine (TBM), considering that the surrounding rocks would produce the force of squeezing into the tunnel, segment damage might occur in the tunnel construction. The large-scale finite element numerical software ANSYS and finite difference software FLAC3D were used to simulate the underpass formation. The stress and strain of tunnel construction segments were comprehensively analyzed, and reasonable monitoring methods and protection measures were put forward. The main conclusions were as follows, when only considering the influence of stratum stress redistribution on lining segments after double tunnel construction, it was suggested that double tunnels should be constructed at the same time, and the displacement of segments was less affected by the direction of tunnel construction; In the construction process, the two adjacent sides of the double tunnel segment would have large horizontal displacement. If necessary, the inner side of the segment should be monitored and reinforced.

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    Design and kinematics analysis of hybrid drive anthropomorphic manipulator
    SHI Zhenjie, LIU Yanjun, XUE Gang, JIA Hua, WANG Yu
    Journal of Shandong University(Engineering Science)    2022, 52 (4): 76-82.   DOI: 10.6040/j.issn.1672-3961.0.2021.488
    Abstract130)      PDF(pc) (6755KB)(26)       Save
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    Power system uniformity planning based on source network coordination
    SUN Donglei, JIAN Qingzhi, LI Zhiqi, HAN Xueshan, WANG Mingqiang, CHEN Bo, FU Yimu
    Journal of Shandong University(Engineering Science)    2022, 52 (5): 92-101.   DOI: 10.6040/j.issn.1672-3961.0.2021.092
    Abstract102)      PDF(pc) (1774KB)(9)       Save
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    Review of risk conflict identification and early warning for interchange
    Jianqing WU,Qifeng WANG,Zhouyuan LI,Yuan TIAN
    Journal of Shandong University(Engineering Science)    2022, 52 (6): 1-13.   DOI: 10.6040/j.issn.1672-3961.0.2022.172
    Abstract87)   HTML7)    PDF(pc) (2835KB)(35)       Save

    This review focused on three parts with data collection method, related indexes of traffic conflict and conflict risk early warning method. Each step of the technology was introduced from range of application, working principle, advantages and disadvantages.Based on the real-time multi-sensor data fusion and roadside early warning method, the future development trend and practical application of risk conflict identification and early warning technology for urban interchanges were prospected.

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    Study on topological characteristics and node centrality of high-speed railway complex network
    Fengbo LAI,Bing XU,Ying XU,Lei ZHANG,Yirong SUN
    Journal of Shandong University(Engineering Science)    2022, 52 (6): 14-22.   DOI: 10.6040/j.issn.1672-3961.0.2022.214
    Abstract69)   HTML0)    PDF(pc) (4976KB)(9)       Save

    Taking the main representative cities in China as the research object, this study analyzed the characteristics and topological characteristics of high-speed railway network, and identifies node cities and their functions in high-speed railway network. The Space-P method was used to build a high-speed network model, and the complex network theory and Pajek analysis software were used to analyze the topological structure and node centrality of of China′s high-speed rail network from the aspects of degree values, average path length, aggregation coefficient and node city centrality. The results showed that China′s high-speed rail network highly aggregated and connected as a whole, the eastern, central and coastal cities showed high aggregation, while the western cities had low high-speed rail network connectivity and weak aggregation. High-speed rail network had the characteristics of a small world, any two nodes could be connected by a small number of transit times, and a few cities need three transit times to be connected. In the high-speed rail network, the cities with large degree values were mainly concentrated in the east, central and coastal regions of China, while the cities in the west and northeast regions had less degree values and large degree centrality, and their proximity centrality was also large. Cities with smaller degree value and greater intermediate centrality had stronger transit ability.

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    Development of numerical calculation for coupled multi-field problems in cracked/porous media
    Yiming ZHANG,Yunpeng LI,Jing LI,Junyu CONG
    Journal of Shandong University(Engineering Science)    2022, 52 (6): 63-78.   DOI: 10.6040/j.issn.1672-3961.0.2022.231
    Abstract64)   HTML0)    PDF(pc) (7360KB)(16)       Save

    Numerical methods of coupled multi-field problems proposed in recent years were reviewed and summarized, from the simple weakly coupled thermo-mechanical to the complicated strongly coupled thermos-hydro-chemo- mechanical problems, from the coupled problem of continuous solid to discontinuous solid. The work was presented in a smooth and progressive manner.This study made a prospect for the future development of multi-field coupling numerical calculation.

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    Eco-driving model for connected and automated vehicle platoons using the traffic capacity remainder
    Shaowei YU,Ruiling QIN,Jingjing GUAN,Can JI,Shuo FENG,Rui JIANG,Yingning LIU
    Journal of Shandong University(Engineering Science)    2022, 52 (6): 23-29.   DOI: 10.6040/j.issn.1672-3961.0.2022.068
    Abstract55)   HTML0)    PDF(pc) (2656KB)(6)       Save

    Aiming at the problems of capacity remainder and high fuel consumption on unsaturated urban and rural traffic roads, this paper proposed an eco-driving model for connected and automated platoons using the capacity remainder, which considered the two goals of fuel economy and traffic capacity, and obtained the optimal speed profiles by solving optimization, to guide a series of small-sized platoons smoothly through the unsaturated urban and rural traffic corridors. In order to improve the computational efficiency of the proposed eco-driving model, this paper proposed an approximate speed optimization model and used genetic algorithm. In order to verify the performance of the proposed model, three control strategies were defined to test the model. The simulation results showed that compared with Strategy 1, Strategy 2 could reduce fuel consumption by 49.4%, increased traffic capacity by 200%, and reduced remaining green time by 14.7%; Strategy 3 could reduce 59.5% of fuel consumption, increased traffic capacity by 200%, and reduced remaining green time by 23.5%. Compared with Strategy 2, Strategy 3 could reduce fuel consumption by 20% without affecting traffic capacity by reducing remaining green time by 10.3% and the average speed by 5.2%. The results showed that when there was traffic capacity remainder at the signalized intersection, the fuel economy could be significantly improved by adjusting the vehicle speed curve to make full use of the traffic capacity remainder.

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    Short-term wind power prediction based on CEEMDAN-GRA-PCC-ATCN
    Xinzhang WU,Xiangyu LIANG,Hongyu ZHU,Dongdong ZHANG
    Journal of Shandong University(Engineering Science)    2022, 52 (6): 146-156.   DOI: 10.6040/j.issn.1672-3961.0.2022.242
    Abstract45)   HTML1)    PDF(pc) (6481KB)(12)       Save

    To improve the accuracy of wind power prediction, a short-term wind power prediction method based on data decomposition and input variable selection was proposed. The complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) was used to decompose the original wind power and wind speed data, and smooth data fluctuation to extract internal hidden information. The wind power components were simplified and reconstructed by permutation entropy (PE) algorithm to reduce the model complexity. To enhance the correlation between the input variables and wind power, eliminate redundant information and reduce the dimensionality of the input data, the Pearson correlation coefficient (PCC) and gray relation analysis (GRA) were combined to select the input variables for each reconstructed wind power component. The attention-based temporal convolutional network was used to predict the reconstructed power components, and the predicted values were superimposed to obtain the final result. The experimental results showed that the short-term wind power prediction method based on CEEMDAN-GRA-PCC-ATCN could extract more internal key information of wind power data, reduce the dimension of input data, strengthen the correlation between input variables and wind power, and effectively improve the prediction accuracy.

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    Named entity recognition model based on dilated convolutional block architecture
    Yue YUAN,Yanli WANG,Kan LIU
    Journal of Shandong University(Engineering Science)    2022, 52 (6): 105-114.   DOI: 10.6040/j.issn.1672-3961.0.2021.304
    Abstract39)   HTML0)    PDF(pc) (8903KB)(6)       Save

    Inspired by the dilated convolution, a column-wise dilated convolution towards two dimensional text embedding was proposed and a dilated convolutional block architecture was designed. A named entity recognition model based on the architecture was built for further experiments. In the named entity recognition experiment, the model surpassed other baseline models in the metrics of precision, recall, and F1 value, respectively reaching 0.918 7, 0.879 4, and 0.898 6, indicating that the dilated convolutional block architecture obtained features from context information, thereby supporting the extraction of the long-term dependency. The receptive field experiment showed that it was necessary to jointly adjust the dilation rate and the convolution kernel size to reduce the "gridding effect". The dilated convolutional block architecture proposed could effectively perform the task of named entity recognition.

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