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    Control Science & Engineering
    Overview of multi-motion vision odometer
    Fengyu ZHOU,Panlong GU,Fang WAN,Lei YIN,Jiakai HE
    Journal of Shandong University(Engineering Science). 2021, 51(1):  1-10.  doi:10.6040/j.issn.1672-3961.0.2020.382
    Abstract ( 402 )   HTML ( 393 )   PDF (3543KB) ( 198 )   Save
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    Multi-motion visual odometry (MVO) was an algorithm for estimating the pose change of dynamic objects in dynamic scenes. It was of great theoretical significance and practical value in autonomous things (AuT). The development process and the latest research progress of multi-motion visual odometer in robot field were reviewed. The important research results of multi-motion visual odometer with the fusion of semantic and geometric features were introduced. Based on the same evaluation criteria and datasets, this research compared several common methods, and prospected the future development direction of multi motion visual odometer.

    Multiobjective dynamic economic emission dispatch differential evolution algorithm based on elites cloning local search
    WU Huihong, QIAN Shuqu, LIU Yanmin, XU Guofeng, GUO Benhua
    Journal of Shandong University(Engineering Science). 2021, 51(1):  11-23.  doi:10.6040/j.issn.1672-3961.0.2020.050
    Abstract ( 242 )   PDF (5001KB) ( 99 )   Save
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    An efficient multiobjective differential evolution algorithm based on elites cloning local search scheme was proposed to solve complex dynamic economic emission dispatch. The conventional differential evolution(DE)algorithm was used as the framework of the proposed algorithm. A cloning operator was developed to enhance the exploration and exploitation ability of elites in the DE algorithm. The elite population to be cloned was established by a dynamic selection mechanism for enhancing the global search ability of the proposed algorithm. To validate the effectiveness of the proposed algorithm, the IEEE 30 bus 10-generator and 15-generator systems were studies as test cases in numerical experiments. The simulation results indicated that the Pareto-optimal front obtained by the proposed algorithm presented a superior performance in convergence and extension over the other reported results recently. As a result, the results were able to provide decision solutions more extensively for decision-makers in power system dispatch.
    Civil Engineering
    Ultimate uplift capacity of shallow vertical plate anchors in sand
    Xiuguang SONG,He YANG,Xiaoyan CHEN,Wenjie CUI,Hongya YUE,Kai ZHANG,Juan TIAN
    Journal of Shandong University(Engineering Science). 2021, 51(1):  24-31, 38.  doi:10.6040/j.issn.1672-3961.0.2020.265
    Abstract ( 303 )   HTML ( 124 )   PDF (5430KB) ( 113 )   Save
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    This paper investigated the pullout behaviour of shallow vertical plate anchors in sand. Pull-out model tests were performed using the particle image velocimetry (PIV) technology, by which the soil deformation and failure mechanisms were observed. Then the ultimate bearing capacity of vertical plate anchors at various soil properties and cover depths was simulated using the finite element limit analysis software. According to the observed failure mechanism, a limit equilibrium solution was developed to calculate the bearing capacity of shallow strip plate anchors in sand, which was then extended for the prediction of the ultimate bearing capacity of rectangle plate anchors by introducing a shape coefficient. Results predicted by the new limit equilibrium solution showed close agreement with those by the lower bound limit analysis solution. The limit equilibrium solution was compared with 51 experimental data, which showed an average of 5% overestimation of the ultimate bearing capacity. This research can provide a theoretical method for the calculation of the ultimate bearing capacity of shallow plate anchors in sand.

    Influence of TBM tunnel excavation at different positions on buildings
    SUN Jie, WU Ke, ZHENG Yang, LI Shuchen, YUAN Chao, WANG Xiuwei
    Journal of Shandong University(Engineering Science). 2021, 51(1):  32-38.  doi:10.6040/j.issn.1672-3961.0.2020.331
    Abstract ( 277 )   PDF (8680KB) ( 119 )   Save
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    In view of the settlement and deformation of existing buildings induced by TBM(tunnel boring machine)tunnel excavation of urban subway, considering the complexity of the actual working conditions of tunnel undercrossing urban buildings, taking the TBM tunnel tunneling in hard rock stratum of Xiaobei Section of Qingdao Metro Line 1 as the actual engineering background, the numerical calculation method was adopted to establish the continuous tunneling of TBM tunnel through several existing buildings. Based on the engineering construction practice, the spatial attribute characteristics of TBM tunnel were systematically studied. The stress-strain state of ground layer and existing buildings induced by TBM tunnel double tunnel driving under existing buildings were studied systematically. The research results showed that the shallower the tunnel depth was, the greater the settlement rate of the buildings affected by the tunnel excavation. In the excavation of double track tunnel, the larger the proportion of buildings affected by the excavation of the tunnel with shorter transverse distance, the greater the tunnel buried depth, the greater the influence of the superposition of double tunnels. When the tunnel passed through the irregular building, it had great influence on the corner of the building and the small building near the large-scale building, so it needed to be monitored in the actual construction.
    Influence of shear span ratio on seismic performance of hollow pipe pier with slot connection
    SU Sibo, WANG Guoqing, JIA Xianzhuo, LI Zhicong, HUANG Zhigang
    Journal of Shandong University(Engineering Science). 2021, 51(1):  39-45.  doi:10.6040/j.issn.1672-3961.0.2020.387
    Abstract ( 277 )   PDF (7608KB) ( 78 )   Save
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    In order to study the influence of shear span ratio on seismic performance of slotted pipe pier with grouted core, based on the bridge engineering of Rongwu New Line Highway, ABAQUS finite element analysis software was used to simulate three kinds of slotted connection pipe pier with different shear span ratio, and the full-scale model of slotted connection pipe pier were made, and the horizontal cyclic load test under constant axial force was carried out to verify the reliability of the finite element model. The results showed that the failure modes of three different shear span ratios were shear failure, bending shear failure and bending failure. With the increase of shear span ratio, the hysteretic performance, energy dissipation capacity and ductility performance of the pipe pier had been significantly improved, but its bearing capacity and residual displacement had little change, the initial stiffness had been strengthened, but the ultimate failure stiffness were basically the same.
    Law of horizontal deformation displacement of tunnels due to adjacent excavation
    LI Lianxiang, ZHANG Qiang, SHI Jinjiang, LIU Jiadian, HOU Yingxue
    Journal of Shandong University(Engineering Science). 2021, 51(1):  46-52.  doi:10.6040/j.issn.1672-3961.0.2020.340
    Abstract ( 315 )   PDF (1666KB) ( 137 )   Save
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    The horizontal displacement of the tunnel hance was divided into three parts. Based on the change of horizontal coefficients of subgrade reaction, the paper proposed the concept of “horizontal deformation displacement”, which was analyzed by the PLAXIS 3D. And the correlation formula between the maximum horizontal deformation displacement and the foundation pit width and the horizontal distance was obtained by fitting. The results showed that the horizontal deformation displacement decreased exponentially with the increase of the horizontal distance between the tunnel and the foundation pit, and the influence of the foundation pit width was ignored when the value of the horizontal distance was greater than the depth of the foundation pit. The formula derived in this paper could be used to calculate the horizontal convergence value of the tunnel adjacent to the excavation, the horizontal displacement of the tunnel hance, and the horizontal coefficients of subgrade reaction near the tunnel.
    Experimental study on stiffness of reinforced concrete pre-cracked beams based on crack parameters
    ZHOU Shuming, YAN Donghuang
    Journal of Shandong University(Engineering Science). 2021, 51(1):  53-59.  doi:10.6040/j.issn.1672-3961.0.2020.403
    Abstract ( 186 )   PDF (1794KB) ( 70 )   Save
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    To research the stiffness characteristics of simply-supported reinforced concrete bridges after cracking in the mid-span, mechanical tests of pre-cracked in the mid-span beams with different nominal damage ratios were carried out. The specimens were cast-in-situ reinforced concrete pre-cracking beams. In the specimens, three different lengths(a=8、18 and 26 mm)of cracks in the mid-span were considered respectively. The evolutions of stiffness reduction coefficient k with nominal damage ratio λ and crack opening w under load of the 8 m standard span reinforced concrete pre-cracked beams were studied through experiments. It was showed that under different test conditions, k decreased with the increase of λ and w. The pre-cracked specimensk decreased little when the crack length was less than the thickness of the protective layer of reinforcement, decreased rapidly when the crack length was near the height of reinforcement. However, the decreased speed appears to fall back when the crack length was higher than the height of the reinforcement. On this basis, a formula for calculating the stiffness reduction coefficient of simply-supported reinforced concrete bridges after cracking in the mid-span was proposed. The effort of this paper could provide a basic for the accurately predicting and evaluating the stiffness characteristics of simply-supported reinforced concrete bridges after cracking.
    True mechanical model of underground pipe corridor supported by piles
    LI Lianxiang, WANG Lei, ZHAO Yongxin, JI Xiangkai
    Journal of Shandong University(Engineering Science). 2021, 51(1):  60-68.  doi:10.6040/j.issn.1672-3961.0.2020.294
    Abstract ( 283 )   PDF (4922KB) ( 94 )   Save
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    In order to study the influence of the pile support system on the real mechanical model of the pipe gallery structure, taking an underground comprehensive pipe gallery project in Jinan as an example, the whole process of the project was simulated by using the Plaxis 3D finite element software. It was found that the stress on the side plate of the underground pipe gallery under the pile support was distributed in three sections: first increase, then decrease, then increase, and obviously less than the static earth pressure, and the internal force of the side plate of the pipe gallery was less than the traditional square law. According to the simulation results, the stress distribution curve and its simplified curve of the side plate of the pipe gallery were obtained by changing the thickness of the covered soil on the top of the gallery. The calculation results showed that the internal force of the side plate of the pipe gallery calculated by the simplified curve was in good agreement with the simulation value, that was to say, the simplified curve had better applicability. According to the simplified curve to calculate the side load of the pipe gallery, the designed pipe gallery structure was more practical, economic and reasonable.
    Electrical Engineering
    Day-ahead optimal scheduling considering the constraints of UHVDC transmission and wheeling contracts
    Dexin LI,Chonglin ZONG,Jiarui WANG,Haifeng ZHANG,Chang LIU,Dawei HUANG
    Journal of Shandong University(Engineering Science). 2021, 51(1):  69-75, 86.  doi:10.6040/j.issn.1672-3961.0.2020.361
    Abstract ( 284 )   HTML ( 14 )   PDF (3689KB) ( 73 )   Save
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    The operational characteristics of ultra-high voltage direct current (UHVDC) transmission and the impact of wheeling contracts on power grid operation and dispatching were analyzed, and a grid-optimized dispatching model considered the constraints of UHVDC transmission and inter-subnet wheeling contracts was established. The model aimed at the minimum operating cost of the power grid and the minimum of wind and photovoltaic curtailment, at the same time, the power constraints of the transmission and wheeling of AC and DC lines were considered, by adding two types of 0-1 variables that characterize power regulation, power up and power down, the stepped constraints of UHVDC transmission lines were expressed as linear equations of 0-1 mixed integers. Taking the improved IEEE39 node system as an example, the impact of UHVDC transmission and wheeling contracts on the grid′s renewable energy consumption was analyzed, and the effectiveness of the proposed method was verified.

    Calculation method of the single-double angle joints in transmission towers
    XU Zaigen, LIU Zhengwei, LIU Wenpeng, ZHOU Mengyao, LIU Juncai, TIAN Li
    Journal of Shandong University(Engineering Science). 2021, 51(1):  87-93.  doi:10.6040/j.issn.1672-3961.0.2020.437
    Abstract ( 245 )   PDF (8478KB) ( 77 )   Save
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    The adoption of combined double angle steel in the lower part of single angle steel as the main material was a common method to effectively improve the bearing performance of the transmission tower, which was conducive to clarifying the force transmission path between variable sections while ensuring high material utilization. However, there were still lack of systematic research and blank in the calculation codes for such joints. Consequently, based on the actual project, 5 typical single-double angle steel joints were selected and modelled in ABAQUS software. The bearing capacity characteristics and force transmission mechanism of the joints were analyzed through numerical simulation. Considering that the bending moment was the main factor affecting the performance of the horizontal plate, different single-double angle steel joints were simulated by changing the eccentricity. The bending moment adjustment factor and the bending moment enhancement factor were raised as the main control parameters in the horizontal plate thickness calculation formula.
    Study on offshore wind farm overvoltage and reactive power compensation
    XU Dapeng, CAI Deyu, ZHAO Lanming, LIU Xumin
    Journal of Shandong University(Engineering Science). 2021, 51(1):  94-99.  doi:10.6040/j.issn.1672-3961.0.2020.393
    Abstract ( 327 )   PDF (5532KB) ( 109 )   Save
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    This paper presented a new methodology for offshore wind farm grid-connection overvoltage and reactive power compensation. The methodology used DIgSILENT PowerFactory software for offshore wind farm modelling, including wind turbine, submarine cable, transformer and relevant control schemes. Moreover, dynamic simulations was performed in time-domain to analyze the active power, reactive power and voltage characteristics of the wind farm under different wind speed conditions. According to the results of the simulations, reactive power compensation devices were configured, and consequently the voltage and power factor condition of the offshore wind farm would be improved, which was also verified by the simulation results.
    Machine Learning & Data Mining
    Unmanned vehicle path planning based on deep Q learning in real environment
    Hao XIAO,Zhuhua LIAO,Yizhi LIU,Silin LIU,Jianxun LIU
    Journal of Shandong University(Engineering Science). 2021, 51(1):  100-107.  doi:10.6040/j.issn.1672-3961.0.2020.247
    Abstract ( 349 )   HTML ( 21 )   PDF (6074KB) ( 133 )   Save
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    It was an important problem for the intelligent navigation of unmanned vehicles that planning the optimal path in the actual traffic environment. At present, many researches about global path planning of unmanned vehicle mainly focused on the improvement of algorithm solution speed in the simulation environment. Most of them just only considered the optimal path distance or the current road conditions, also ignored other factors and future changes in the actual environment. In order to complete the complex task that competing global path planning of unmanned vehicle in dynamic road network, this research put forward a framework of unmanned vehicle driving system for practical environment based on the thought of planning after prediction, and put forward DP-DQN which was a fast global path planning method combined with deep Q learning and deep prediction network technology. This method used the road characteristic data such as time and space, weather et al to predict the future traffic situation, and then competed the global optimal path. Finally, experimental results based on open datasets showed that the proposed method reduced driving time 17.97% at most than Dijkstra, A*, algorithm et al.

    Multi-kernel combination method based on rank spatial difference
    WANG Mei, XUE Chenglong, ZHANG Qiang
    Journal of Shandong University(Engineering Science). 2021, 51(1):  108-113.  doi:10.6040/j.issn.1672-3961.0.2020.248
    Abstract ( 258 )   PDF (444KB) ( 94 )   Save
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    A multi-kernel combination method based on rank spatial difference was proposed in this paper. samples were grouped according to characteristics, different kernel functions are used to train the grouped data, and the parameters of the kernel function are optimized by grid search method. Two kernel functions were selected from the alternative kernel functions, and the data divided into two groups were respectively put into the corresponding kernel function for mapping. Then the rank spatial difference of the data after the kernel function mapping was judged to provide reference for the selection of the basic kernel function. The wine data set, the breast cancer data set and the wine quality data set were selected for the experiment to verify that when the data were mapped by the selected basic kernel function, the greater the rank space difference was, the higher the classification accuracy was. The experimental results showed that the method was feasible for the selection and combination of basic kernel functions.
    Novel guidewire modeling method based on Energy minimum theory
    WANG Yu, LIU Hao
    Journal of Shandong University(Engineering Science). 2021, 51(1):  114-119.  doi:10.6040/j.issn.1672-3961.0.2020.364
    Abstract ( 221 )   PDF (4431KB) ( 107 )   Save
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    A high-performance guidewire model was demanded in the VR(virtual reality, VR)training system for endovascular interventional surgery. A new guidewire modeling method was proposed. This method used a cylindrical rigid body with hemispherical ends as the basic unit of the guidewire and the geometric characteristics of the model itself combined the principle of minimum energy to obtain the guidewire deformation parameters when the guidewire was inserted into the target blood vessel branch, which improved the accuracy and flexibility of the guidewire. Combined with the developed guidewire manipulator, the established guidewire achieved good performance and keeped synchronization with it during the experiment, which helped novices to immerse in the training environment.
    Emission characteristics of PM1.0-bound polycyclic aromatic hydrocarbons(PAHs)from different stoves and fuels in rural areas
    DUAN Shengfei, YANG Lingxiao, LI Jingshu, GAO Hongliang, ZHANG Wan, ZHANG Xiongfei, QI Anan, WANG Pengcheng, WANG Yiming, TUO Xiong
    Journal of Shandong University(Engineering Science). 2021, 51(1):  120-127.  doi:10.6040/j.issn.1672-3961.0.2020.513
    Abstract ( 225 )   PDF (4446KB) ( 82 )   Save
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    To study the emission factors and emission characteristics of PM1.0-bound PAHs from the combustion of different fuels and improve stoves in rural areas, the samples produced by 8 fuels burned in 2 improved stoves were collected using the dilution channel method, and the concentration of PAHs was analyzed. The results showed that the emission factor was in the range of 0.38~39.37 mg·kg-1. When the same fuel was burned in different improved stoves, the gasifier stoves emission factor of PAHs was lower than the decoupling stoves. The order of PAHs emission factors of various fuels burned in the gasifier stove was EFbulk coal>EFcorn straw>EFbituminous coal briquette>EFpine wood>EFoak wood>EFsemi-coal≈ EFanthracite briquette>EFcorn straw briquette. Among biomass fuels, PHE, PLA, and PYR were the main species of PAHs produced by combustion, while the dominant species in coals were PHE, FLA, PYR, and BbF. The proportion of LMW PAHs produced by the gasifier stove was higher than the decoupling stove, while the proportion of MMW PAHs and HMW PAHs produced by the gasifier stove was lower than the decoupling stove. In the case of meeting the heating demand of residents, it was estimated that the best combination was gasifier stove+semi-coke, anthracite briquette, or corn straw briquette.
    Impact analysis of road traffic on urban air quality in congested environment
    FENG Haixia, WANG Qi, YANG Licai, KOU Junying, XIE Qingmin, ZHAO Junxue, MENG Xianglu, WANG Yanfeng
    Journal of Shandong University(Engineering Science). 2021, 51(1):  128-134.  doi:10.6040/j.issn.1672-3961.0.2020.211
    Abstract ( 531 )   PDF (3465KB) ( 166 )   Save
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    Focusing on research hot issues of traffic congestion, haze(air quality), and the main urban area of Jinan taken as an example, the paper quantitatively analyzed the impact of peak congestion delay index and traffic operation index on urban air quality. Combining with satellite retrieval of aerosol optical depth(AOD ), the impact of road traffic on air quality in congestion environment was quantitatively analyzed based on geographical weighted regression model. The results showed that there was a strong correlation between the peak congestion delay index and the air quality index. The traffic operation had great influence on air quality. Geographically weighted regression(GWR)refined local spatial features. Under traffic congestion conditions, the road area occupancy rate had the greatest impact on air quality in the region. The paper had certain guiding significance for traffic planning and provided support for traffic planning and control.