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    Machine Learning & Data Mining
    Evacuation simulation model based on multi-target driven artificial bee colony algorithm
    Xinlu ZONG,Jiayuan DU
    Journal of Shandong University(Engineering Science). 2021, 51(3):  1-6.  doi:10.6040/j.issn.1672-3961.0.2020.259
    Abstract ( 426 )   HTML ( 532 )   PDF (4584KB) ( 128 )   Save
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    An evacuation simulation model based on multi-target driven artificial bee colony algorithm was presented. Based on the artificial bee colony algorithm, the visual field was used for each following bee to choose the individual with the best fitness value in the field as its visual leading bee and avoid blind choice. A multi-target driven artificial bee colony algorithm was proposed. The moving direction of each following bee was affected by multiple targets, including inertial leading bee, global optimal bee, historical optimal bee and visual leading bee. The experimental results showed that the multi-target driven artificial bee colony algorithm had higher efficiency and achieved better performance and more reasonable distribution in the case of larger number of evacuees. The model and algorithm presented could effectively improve evacuation efficiency and was suitable for the evacuation problem in multi-obstacle situation.

    Median calculation algorithms based on GPU in OLAP
    WU Zhenpeng, ZHANG Jian, FAN Xingqi, LI Cuiping
    Journal of Shandong University(Engineering Science). 2021, 51(3):  7-14.  doi:10.6040/j.issn.1672-3961.0.2019.508
    Abstract ( 373 )   PDF (3119KB) ( 107 )   Save
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    An algorithm for one of the holistic aggregate operations in online analytical processing(OLAP)called Median was proposed based on graphics processing unit(GPU), which was named GPU-Median algorithm. This algorithm obtained the median of a series of data by segmenting the data, sorting the data by segments,cutting the data preceding the global median, and finally merging the uncut data. Through the algorithm above much time spent on global sorting was saved. Then an algorithm called GPU-Median+was presented in order to optimize and extend the GPU-Median algorithm. This algorithm implemented the aggregate operations through the collaboration of CPU and GPU, which used GPU to deal with segments of data and CPU to deal with global data. Experiments and analysis proved that the GPU-Median + algorithm reduced the time complexity of the median calculation from O(n2)to O(n)compared to the CPU algorithm,and that the GPU-Median + algorithm reduced a third of the calculation time compared to the radix sort algorithm on the GPU. The application of this algorithm enabled the GPU to improve its ability of parallel calculations when calculating the holistic aggregate function in OLAP, thus providing a new idea for improving the query performance of OLAP.
    Adaptive multi-domain sentiment analysis based on knowledge distillation
    YANG Xiuyuan, PENG Tao, YANG Liang, LIN Hongfei
    Journal of Shandong University(Engineering Science). 2021, 51(3):  15-21.  doi:10.6040/j.issn.1672-3961.0.2020.249
    Abstract ( 362 )   PDF (2317KB) ( 144 )   Save
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    An adaptive multi-domain knowledge distillation framework was proposed, which effectively accelerated reasoning and reduced model parameters while ensuring model performance. The knowledge distillation method was used to study sentiment analysis problems. When performing knowledge distillation for each specific field, model distillation involved word embedding layer distillation, coding layer distillation(attention distillation, hidden state distillation), output prediction layer distillation and other aspects of distillation, in order to learn all aspects knowledge from the specific field teacher model. Selectively learning the importance of the teacher model corresponding to different fields to the data was proposed, which further improved the accuracy of the prediction results. The experimental results on multiple public datasets showed that after single-domain knowledge distillation increased the model accuracy by an average of 2.39%, while multi-domain knowledge distillation increased the model accuracy by an average of 0.5%. Compared with the knowledge distillation of a single domain, this framework enhanced the generalization ability of the student model and improved the performance.
    Small sample person re-identification combining Gabor features and convolution features
    FU Guixia, ZOU Guofeng, MAO Shuai, PAN Jinfeng, YIN Liju
    Journal of Shandong University(Engineering Science). 2021, 51(3):  22-29.  doi:10.6040/j.issn.1672-3961.0.2020.232
    Abstract ( 368 )   PDF (6150KB) ( 125 )   Save
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    In the video surveillance, the limited available person images and unreliable data annotation led to the performance degradation of supervised person re-identification. To solve these problems, we proposed an unsupervised small sample person re-identification method that integrated Gabor features and convolution features. Gabor transform was used to extract multi-scale and multi-direction person texture and edge information, so as to realize the data augmentation of small sample person images in feature level. The redundant information was eliminated by feature encoding to improve the efficiency of feature similarity calculation. The convolutional auto-encoder network was adopted to extract the nonlinear deep convolution feature of pedestrian, which avoided the dependence of supervised learning algorithm on data annotation. The fusion of two heterogeneous features was applied to person similarity comparison, which implemented the feature augmentation of small samples and the improvement of person feature discrimination ability. Experiments were implemented based on Market-1501 and DukeMTMC-reID datasets, the rank-1 accuracy reached 74% and 67.1% respectively. The experimental results showed that the proposed network framework effectively improved the performance of small sample person re-identification.
    Automatic detection research of arrhythmia based on CNN-LSTM hybrid model
    TAO Liang, LIU Baoning, LIANG Wei
    Journal of Shandong University(Engineering Science). 2021, 51(3):  30-36.  doi:10.6040/j.issn.1672-3961.0.2020.445
    Abstract ( 494 )   PDF (3912KB) ( 242 )   Save
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    A hybrid algorithm of convolutional neural network and long short-term memory network was proposed for automatic detection of arrhythmias. The model structure was composed of 5 convolutional layers, 5 pooled layers, 1 LSTM layer and 1 fully connected layer. By taking advantage of CNN's ability to automatically extract features and LSTM's ability to capture dependencies before and after time series, the simple preprocessed ECG signal data were directly input into the hybrid model. The whole model combined the two steps of feature extraction and classifier classification, so as to identify five different arrhythmias more efficiently and accurately. The accuracy, sensitivity and specificity of the test set were 99.48%, 99.47% and 99.86% respectively. The experimental results showed that the proposed method could efficiently and accurately identify different types of arrhythmias.
    Algorithm of adaptive slope adjustment of quadruped robot based on model predictive control and its application
    LIANG Qixing, LI Bin, LI Zhi, ZHANG Hui, RONG Xuewen, FAN Yong
    Journal of Shandong University(Engineering Science). 2021, 51(3):  37-44.  doi:10.6040/j.issn.1672-3961.0.2020.320
    Abstract ( 416 )   PDF (6868KB) ( 230 )   Save
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    In order to realize the adaptive and stable walking of the quadruped robot on slope terrain, the adaptive adjustment strategies of both feet position and trunk posture of quadruped robot on slope were proposed based on the model predictive control. The posture determination parameters of the robot in locomotion were measured by the inertial measurement unit(IMU). By means of the derived foot end trajectory algorithm, the coordinate mapping of its toe position was obtained in order to adjust the center of gravity of the robot on the slope. Then the adaptive adjustment of the trunk posture of the robot in the process of climbing could be achieved through the trunk posture adjustment algorithm by means of designed “virtual slope”. With the help of the physical platform of quadruped robot and the actual slope terrain environment built in the laboratory, the feasibility and validity of the proposed algorithm are verified. Experimental result showed that the proposed slope adaptive control method had improved the stability margin of the robot on the slope and optimized the foot end motion space, thus leading to the realization of adaptive adjustment in climbing slope for the quadruped robot.
    Civil Engineering
    Study on full face hard rock tunnel boring machine through the overpass in composite stratum
    Chunguo WANG
    Journal of Shandong University(Engineering Science). 2021, 51(3):  45-51.  doi:10.6040/j.issn.1672-3961.0.2020.525
    Abstract ( 336 )   HTML ( 169 )   PDF (8639KB) ( 84 )   Save
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    By using the numerical calculation method, the double tunnel underpass overpass was established according to the actual engineering situation, the strain law of the tunnel underpass municipal bridge was comprehensively analyzed, the multi-point displacement of the bridge was monitored, and the weak point reinforcement measures of the tunnel orthogonal underpass bridge were proposed. The results showed that the influence of the two-way simultaneous excavation of the right tunnel was almost the same as that of the two-way simultaneous excavation of the right tunnel. The left tunnel was excavated first and then the right tunnel was excavated. The uplift part of the bridge deck would gradually subside with the excavation of the right tunnel. It could be seen that the left tunnel excavation first and then the right tunnel excavation had the largest impact on the bridge deck, which was easy to cause the uneven settlement of the bridge. The uneven settlement of bridge deck caused by tunnel excavation could temporarily support and reinforce the piers, and the circumferential soil around the piers could be replaced with concrete to reduce the settlement of the piers and bridge deck.

    Optimization of ventilation system of TBM tunnel construction and evaluation of dust suppression effect
    WANG Chunguo
    Journal of Shandong University(Engineering Science). 2021, 51(3):  52-60.  doi:10.6040/j.issn.1672-3961.0.2020.468
    Abstract ( 376 )   PDF (5863KB) ( 145 )   Save
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    Hard rock tunneling boring machine(TBM)produces a large amount of dust during construction, which is an important factor affecting the operating environment and the health of workers. To further optimize the construction ventilation and dust removal effect, combined with the actual working conditions of Qingdao Metro Line 1 double shield TBM, Ansys-Fluent software was used to carry out numerical analysis of the tunnel excavation process. The wind speed and dust mass concentration at each location of the tunnel were detected and compared with the numerical simulation results to verify the effectiveness of the model. In view of whether it is necessary to open the dust removal system in the process of TBM tunnel construction, as well as the location of dust removal tuyere and the selection of optimal suction flow, numerical simulation was carried out. When the dust removal system was turned off or the dust removal system was turned on but the suction flow was below 4 m3/s, and the dust diffuses to most areas of the TBM tunneling area. When the dust duct was 15 m away from the hand surface and the suction airflow was 12 m3/s, the dust removal effect reached the best, and the dust diffusion distance was reduced to 45 m, which could effectively remove dust. The research results could provide a scientific basis for the design and construction of tunnel ventilation and dust removal.
    Location optimization of median BRT station at intersection
    GUO Rongrong, ZHANG Ruhua, MA Xinhui, GUO Senyao
    Journal of Shandong University(Engineering Science). 2021, 51(3):  61-67.  doi:10.6040/j.issn.1672-3961.0.2020.345
    Abstract ( 331 )   PDF (1618KB) ( 99 )   Save
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    Based on the optimal comprehensive time efficiency of BRT vehicles and arriving passengers, a station selection optimization method was proposed. The time efficiency model was established and calculated by fuzzy analytic hierarchy process and genetic algorithm. Huanggang Road Station in Jinan was selected for case analysis. The results showed that the larger the weight of BRT operation time in a measurement unit was, the smaller the weight of arrival passenger travel time was, and the greater the buffer distance when the time efficiency was optimal. When the case station was set up at 25 meters downstream of the intersection, the efficiency of comprehensive time was the most optimal, which was 20% higher than the current situation.
    Forward modeling analysis of seismic wave field for TGS360pro advanced prediction of groundwater: taking the karst model as an example
    ZHANG Mingcai, JU Guanghong, XIONG Zhangqiang, ZHANG Dazhou
    Journal of Shandong University(Engineering Science). 2021, 51(3):  68-75.  doi:10.6040/j.issn.1672-3961.0.2020.158
    Abstract ( 382 )   PDF (8916KB) ( 132 )   Save
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    In order to avoid the occurrence of water gushing accident due to the inaccurate detection of the underground water storage state in front of the tunnel during the excavation of the tunnel, the tunnel geology survey TGS360pro System was used to accurately and efficiently detect the water-bearing body in front of the tunnel face by using the relation between the instantaneous amplitude and frequency of seismic wave signal and the rock structure plane, at the same time, based on the principle of TGS360pro tunnel Prediction System, the geological model with water-filled cave in front of the face was simulated by using spectral element method, through the stress curve, the numerical analysis results showed that the TGS360pro Tunnel Prediction System could effectively detect the water-rich condition in front of the tunnel, it had the prospect of popularization and application in tunnel excavation construction.
    Electrical Engineering
    Prediction method of power grid emergency supplies under meteorological disasters
    Qingfa CHAI,Shoujing SUN,Jifu QIU,Ming CHEN,Zhen WEI,Wei CONG
    Journal of Shandong University(Engineering Science). 2021, 51(3):  76-83.  doi:10.6040/j.issn.1672-3961.0.2020.527
    Abstract ( 389 )   HTML ( 138 )   PDF (2767KB) ( 64 )   Save
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    In order to improve the efficiency of grid emergency repairs, a method for predicting emergency supplies under the conditions of power grid meteorological disasters combining case-based reasoning, deep belief network and deep learning was proposed. Based on meteorological data, power grid maintenance data and geographic environment data, this method was used case-based reasoning to determine the appropriate input and output structure of the prediction model, and different methods was used to process and quantify according to the characteristics of disagreeing input factors. Deep belief networks were used to complete case adaptation, and integrate accident scale information was used to establish a dynamic power grid emergency supplies prediction model. The analysis results showed that the emergency material prediction method proposed in this paper could comprehensively analyze various characteristic factors, and combined the scale of the accident to establish the relationship between the emergency material demand of the power grid, and accurately predicted the material demand for the emergency response of the power grid under the weather disaster. and provided a scientific reference for emergency decision-making of power grids.

    Method for safety management and control of tools and equipment used in substation based on ultra-wideband technology
    LI Ying, L(¨overU)Xuebin, LI Yan, SUN Shoujing
    Journal of Shandong University(Engineering Science). 2021, 51(3):  84-90.  doi:10.6040/j.issn.1672-3961.0.2020.243
    Abstract ( 261 )   PDF (4805KB) ( 45 )   Save
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    A method for the safety management and control of construction tools based on ultra-wideband technology was propssed. The function ultra wide band technology information storage and high-precision positioning was used, through the link before, during, and after the use of tool management, to eliminate the blind area of tool information and safety management and control and prevent. Major hidden dangers to the safe operation of substations due to improper use of tools and improper disposal. In addition, through the on-site disposal of damaged tools, the management and control of tools was fundamentally improved.
    Reduced-order analytical model to evaluate photovoltaic low-voltage ride-through performance
    NIU Shuanbao, HUO Chao, CHEN Chunmeng, KE Xianbo, WANG Xiaohui, ZHANG Qiang, CHEN Ning
    Journal of Shandong University(Engineering Science). 2021, 51(3):  91-100.  doi:10.6040/j.issn.1672-3961.0.2020.472
    Abstract ( 310 )   PDF (3951KB) ( 94 )   Save
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    A reduced-order analytical model to evaluate the performance of PV in case of low-voltage ride through(LVRT)was proposed based on the idea of order reduction at each unit, focusing on the DC bus voltage which determined the outcome of ride-through. Such a method covered the major factors with regard to PV LVRT, and included the responses by the converter controller and phase-locked loop. Meanwhile, it took the supporting of reactive power outputs from PV on the point of common coupling(PCC)voltage into consideration, so as to reflect that PV provides reactive power support to AC system. To validate the proposed reduced-order analytical model, the comparison with the simulation results derived from PSCAD confirmed its accuracy and feasibility.
    Wind induce vibration control of chimney with suspended flue
    LI Xu, LIU Bing, CHEN Ying, WANG Peijun
    Journal of Shandong University(Engineering Science). 2021, 51(3):  101-112.  doi:10.6040/j.issn.1672-3961.0.2020.281
    Abstract ( 316 )   PDF (4454KB) ( 84 )   Save
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    The wind induced vibration control of a high rise reinforced concrete chimney with suspended flues(CSMF)was conducted by using rotational friction dampers(RFD). The detailing of a RFD restraint joint was presented. The wind induced vibration control effect was firstly investigated, and the state space formulation of the equation of motion of CSMF was derived based on Lagrange's equations. A CSMF of 175 m high was then taken an example to investigate the feasibility of the proposed control strategy. Five vibration control schemes were compared and the results showed that the vibration of CSMF could be substantially suppressed by using RFD with optimal parameters, position and suspended flue length. FRD was superior to TMD due to its small auxiliary mass and little space occupation.
    Comprehensive protection scheme for grounding fault in low resistance grounding system
    HUANG Fuquan, WANG Tinghuang, ZHANG Haitai, LIU Zijun, LI Guodong
    Journal of Shandong University(Engineering Science). 2021, 51(3):  113-118.  doi:10.6040/j.issn.1672-3961.0.2020.159
    Abstract ( 402 )   PDF (2199KB) ( 117 )   Save
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    Because the existing grounding protection in low resistance grounding system had imcomplete protection configuration, poor selectivity, low sensitivity and insufficient ability to detect high-imedance grounding fault, the characteristics of zero sequence current while single-phase grounding fault occured in low resistance grounding system was analyzied. With the help of longitudinal cooperation between the upper and lower protections, the multistage grounding protection based on zero sequence current and the high sensitivity grounding protection based on low setting and time delay were proposed, and also the grounding protection configuration scheme and the setting principles at all levels were discussed. Fault line selection method was proposed for the high-impedance grounding fault using the lateral comparasion of the amplitudes of zero sequence currents between the outlet of each feeder and the neutral line. The feasibility and reliability of the proposed comprehensive protection scheme for grounding fault were verified by the simulation in a typical small resistance grounding distribution network.
    Chemistry and Environment
    Pollution characteristics and intake risk assessment of short and medium-chain chlorinated paraffins in foods in Jinan
    Xinxin FANG,Shiwen ZHANG,Yuting ZHU,Wei JIANG,Zhaoyuan ZHANG,Nan ZHAO
    Journal of Shandong University(Engineering Science). 2021, 51(3):  119-128.  doi:10.6040/j.issn.1672-3961.0.2021.001
    Abstract ( 315 )   HTML ( 182 )   PDF (3853KB) ( 165 )   Save
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    To explore the distribution status and intake risk of short-chain chlorinated paraffins (C10-13, SCCPs) and medium-chain chlorinated paraffins (C14-17, MCCPs) in food in Jinan city, 82 kinds of food were collected in Jinan in 2020 and analyzed by chlorine enhanced atmospheric pressure chemical ionization source- four-stage pole time-of-flight mass spectrometry. The results showed that the concentration of wet weight of SCCPs in food samples ranged from 5.3 to 2 483.2 ng/g, MCCPs ranged from 4.6 to 605.1 ng/g. The concentration of wet weight of SCCPs in Peanut oil was the highest, which was 2 115.5 ng/g. The concentration of wet weight of SCCPs in balsam pear was the lowest, which was 5.7 ng/g. The concentration of wet weight of MCCPs in soybean oil was the highest, which was 605.5 ng/g. The concentration of wet weight of MCCPs in Chinese cabbage was the lowest, which was 6.2 ng/g. The estimated daily intake (EDI) of SCCPs was the highest in staple foods, which was 2 619.2 ng/(kg ·d) and the lowest in aquatic foods, which was 17.7 ng/(kg ·d). The EDI of MCCPs was the highest in staple foods, which was 2 117.6 ng/(kg ·d), and the lowest in aquatic foods, which was 12.1 ng/(kg ·d). The hazard quotients (HQ) of SCCPs、MCCPs was 0.041 and 0.032, respectively. The purpose of this study was to provide reference data for the assessment of the risk of exposure to CPs among the population in Jinan.