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Product Competitiveness Analysis Method Based on Online Reviews TIAN Jin-ni， YOU Tian-hui， YUAN Yuan Journal of Northeastern University(Natural Science)    2021, 42 (10): 1498-1505.   DOI: 10.12068/j.issn.1005-3026.2021.10.018 Abstract （3276）   HTML （10）    PDF （590KB）（394）       With the development of e-commerce， online reviews have been regarded as important data resources for enterprises to analyze the competitiveness of their products. Product feature dimensions that consumers pay most attention to were extracted from review texts. The sentiment analysis of review texts was performed based on the sentiment lexicon method to obtain the feature-sentiment score pairs. The opportunity scores of feature dimensions were calculated by the importance degree and satisfaction degree， and an opportunity landscape diagram was drawn to analyze the competitiveness of the target product itself. Feature dimension satisfaction degree was calculated to compare the competitive advantages and disadvantages between the target product and its competitive products. Competitiveness improvement strategies of the target product were given by considering the competitiveness analysis results from two perspectives comprehensively. The online reviews provided by Zol.com.cn were used to conduct experiments to illustrate the feasibility and effectiveness of the proposed method. Reference | Related Articles | Metrics

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Effect of ZrO 2 content on the density of nNaF·AlF 3 -Al 2 O 3 - CaF 2 molten salt system Bao, Morigen-Gaowa (1); Wang, Zhao-Wen (1); Gao, Bing-Liang (1); Shi, Zhong-Ning (1) Journal of Northeastern University    2012, 33 (6): 866-869.   DOI: - Abstract （3119）   HTML    PDF （439KB）（669）       The density of nNaF·AlF 3 -Al 2 O 3 - CaF 2 -ZrO 2 molten salt system with different molar ratio of NaF to AlF 3 and ZrO 2 contents was determined based on Archimedes law, and the effects of temperature and ZrO 2 content were investigated. The results show that the density decreases with the increasing of temperature and the decreasing of molar ratio of NaF to AlF 3 . At 980°C, there is a good linear relationship between the density of 2.4NaF·AlF 3 -3wt%Al 2 O 3 - 3wt%CaF 2 molten salt system and the ZrO 2 content of 0~5wt%, which can be expressed as ρ t (g·cm -3) = 0.02844·w(ZrO 2 )+2.045 (r=0.9992). Within the present study range, the electrolyte density increases approximately by 0.02 g/cm 3 with 1wt% ZrO 2 addition. Reference | Related Articles | Metrics

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Feature Selection Algorithm Based on LightGBM LI Zhan-shan， YAO Xin， LIU Zhao-geng， ZHANG Jia-chen Journal of Northeastern University(Natural Science)    2021, 42 (12): 1688-1695.   DOI: 10.12068/j.issn.1005-3026.2021.12.003 Abstract （2877）   HTML （76）    PDF （419KB）（7616）       In order to solve the shortcomings of the following two types of feature selection algorithms， filtering and wrapping based on evolutionary learning， a new wrapping feature selection algorithm LGBFS(LightGBM feature selection) was proposed. First， LightGBM was introduced to construct an gradient boosting tree model for the original features and measure the importance of features; then the proposed LR sequential forward search strategy LRSFFS was combined to select features; finally， the proposed algorithm was compared with nine algorithms in 21 standard datasets. The results show that 16 of the 21 standard data sets of LGBFS have achieved the best classification accuracy， and 18 standard data sets have achieved the best dimensionality reduction rate and the best CPU running time. In addition， time complexity analysis and significance test were carried out. The test shows that LGBFS is significantly different from the six comparison algorithms， and it also shows that LGBFS can balance the calculation efficiency and classification accuracy of feature subsets. Reference | Related Articles | Metrics

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Entity Alignment Algorithm for Knowledge Graph of Representation Learning ZHU Ji-zhao， QIAO Jian-zhong， LIN Shu-kuan Journal of Northeastern University Natural Science    2018, 39 (11): 1535-1539.   DOI: 10.12068/j.issn.1005-3026.2018.11.004 Abstract （2825）   HTML    PDF （394KB）（2075）       A novel supervised method for knowledge graph entity alignment based on representation learning was proposed， which is different from the existing methods due to the similarity of structural information or attributive characters. First， the method automatically learns the semantic representations for the entities and relations of a knowledge graph in a low-dimensional vector space was proposed， and these embeddings contain the intrinsically structural information of a knowledge graph and the attributive features of entities. Afterwards， taking the manually aligned entity pairs as prior knowledge， the cross-KG mapping relationship between entities could be learned， which will be used for predicting entity alignment. Experiments conducted on real datasets demonstrated that our method can effectively improve the precision of knowledge graph entity alignment while keeping a high F1 score， when compared with the feature matching based method SiGMa. Reference | Related Articles | Metrics

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Pavement Crack Detection Algorithm Based on Subregion and Multiscale Analysis LU Ziwei， WU Chengdong， CHEN Dongyue， SHANG Shibo Journal of Northeastern University Natural Science    2014, 35 (5): 622-625.   DOI: 10.12068/j.issn.1005-3026.2014.05.004 Abstract （2254）   HTML    PDF （676KB）（846）       In order to improve the accuracy of highway pavement crack detection， a new type of surface defects detection algorithm was proposed based on subregion and multiscale analysis. Gray， entropy and texture features distribution information were extracted in cracks and the surrounding areas from different scales of images. Feature vectors of parameters containing the direction trend and bending degree were acquired， and the crack location was detected through learning the support vector machine (SVM) and judging the eigenvector. Experimental results demonstrated that the resistance to noise， versatility and detection accuracy were improved effectively by the proposed algorithm in comparison to the other pavement cracks detection algorithms. The ideal crack detection effect was achieved， and the requirements of highway quality inspection were met effectively. Reference | Related Articles | Metrics

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Object Detecting and Tracking Algorithm Based on Optical Flow XIAO Jun， ZHU Shi-peng， HUANG Hang， XIE Ya-nan Journal of Northeastern University Natural Science    2016, 37 (6): 770-774.   DOI: 10.12068/j.issn.1005-3026.2016.06.003 Abstract （2176）   HTML    PDF （318KB）（2255）       Harris corner points were adopted as tracking objects， and scale space was introduced into corner point detection in order to extract Harris corner points in feature scale. Then curvature was computed to filter out false corners and enhance adaptability to scale change. Optical flow method was adopted for the tracking algorithm based on image pyramid， in which the optical flow iteratively was computed. And the tracking algorithm based on the optical flow error was proposed. That is， the trajectory error in the same frame with different time flow was used to evaluate the tracking situation. In this way， tracking failure was avoided when the tracking object is hidden， disappears or textural features change. Experimental results of different video sequences show that the proposed optical flow tracking algorithm based on improved corner extraction and image pyramid has better tracking performances. The feature points could be filtered effectively that lead to tracking failure with the introduction of optical flow error method， and the object positions are estimated accurately. Reference | Related Articles | Metrics

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An Effective Proportional Fairness Algorithm LIU Fulai， QIU Huizhen， ZHOU Qingping， DU Ruiyan Journal of Northeastern University Natural Science    2014, 35 (11): 1535-1538.   DOI: 10.12068/j.issn.1005-3026.2014.11.004 Abstract （2002）   HTML    PDF （455KB）（836）       To solve the spectrum resource allocation problem of multiuser in cognitive radio system based on OFDM， a bit and power allocation algorithm was proposed. Firstly， the transmit power of secondary users was constrained to guarantee the communication quality of service (QoS) of secondary user. Secondly， the twostep method and the proportion gene were used to avoid the disequilibrium of spectrum resource allocation. Finally， the algorithm was simulated and the results of the allocation about secondary users showed that the presented method could not only guarantee each user’s QoS but also increase the channel capacity. Reference | Related Articles | Metrics

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Traffic Target Detection in Complex Scenes Based on Improved YOLOv5 Algorithm GU De-ying， LUO Yu-lun， LI Wen-chao Journal of Northeastern University(Natural Science)    2022, 43 (8): 1073-1079.   DOI: 10.12068/j.issn.1005-3026.2022.08.002 Abstract （1992）   HTML （81）    PDF （2504KB）（934）       Real-time target detection in traffic scenarios is the prerequisite of electronic monitoring， automatic driving， and other functions. In view of the low detection efficiency of existing target detection algorithms and the low accuracy of most light target detection algorithms， which are easy to obtain wrong or insufficient target detection， this paper adopts the improved YOLOv5 target detection algorithm for model training， and the pseudo-label strategy for training process optimization. Then， the KITTI traffic target dataset tags are merged into three categories for model training and testing. Through the experimental comparison， the improved YOLOv5 model in this paper achieves 92.5% mAP in all categories， which is 3% higher than the original YOLOv5 training model. Finally， the three categories of the trained models are deployed on the Jetson Nano embedded platform for inference testing， and TensorRT is used to accelerate inference. The average inference time per frame of image is 77ms， which meets the goal of real-time detection. Reference | Related Articles | Metrics

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A Thermodynamic Model of Phosphate Capacity of CaO–SiO2–MgO–FetO–P2O5 Steelmaking Slags

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Trajectory Tracking Control of Unmanned Vehicles Based on Adaptive MPC LIANG Zhong-chao， ZHANG Huan， ZHAO Jing， WANG Yong-fu Journal of Northeastern University Natural Science    2020, 41 (6): 835-840.   DOI: 10.12068/j.issn.1005-3026.2020.06.013 Abstract （1980）   HTML    PDF （562KB）（2402）       According to the principle of adaptive MPC(model predictive control)， a trajectory tracking control strategy for unmanned vehicles is designed. Based on the vehicle dynamics model， the trajectory tracking controller is established， and the objective function and related constraints are designed. The adaptive MPC control algorithm is used for solution. At each control point of operation， the Kalman state estimator correlation gain coefficient matrix and the state of the controller are continuously updated to adapt to the current working environment of the unmanned vehicle， thereby compensating for the nonlinearity of the vehicle and the effect of state measurement noise. The simulation model is built in MATLAB and verified by simulation. It is concluded that the adaptive MPC has better control precision and robustness for the trajectory tracking of unmanned vehicles. The effectiveness of the algorithm in the trajectory tracking control layer is verified. In addition， it provides a reference for the research of future trajectory tracking control. Reference | Related Articles | Metrics

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Heavy Metal Pollution and Potential Risk Assessment of Soil in Fushun Western Open-Pit Mining Area JIANG Bin-hui， ZHANG Bo， WANG Xue-feng， JIANG Qi Journal of Northeastern University Natural Science    2020, 41 (4): 568-574.   DOI: 10.12068/j.issn.1005-3026.2020.04.020 Abstract （1955）   HTML    PDF （558KB）（952）       By measuring the heavy metal content in the typical area of the mining area， it is found that Cd is the characteristic element of the heavy metal pollution in the mining area. The pollution degree and the potential ecological risk caused by the heavy mental pollution were evaluated by using the single factor pollution index method， the Nemero pollution index method and the potential hazard index method respectively. The results showed that the average values of single element pollution index and Nemero pollution index of Cd are 4.06 and 5.32， respectively， both indicate a heavy pollution. The Nemero pollution index of the three ecological restoration areas are 2.07~4.57， among which the south natural ecological restoration(SNER) area is heavy pollution and the other areas are moderate pollution. The potential ecological risk index of heavy metals in the mining area is 98.62~224.55， the SNER area reaches the medium hazard level， and the remaining areas are evaluated as mild ecological hazards. Reference | Related Articles | Metrics

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MDS-MAP Localization Algorithm Based on Estimated Distances    0, (): 0-0.   Abstract （1925）   HTML          To address the high localization error of range-free localization algorithms, this paper proposes a MDS-MAP localization algorithm based on estimated distances. First, we analyze the relation between the distance of two neighbor nodes and the intersection area of them, and get a function. The input of the function is the number of nodes within the intersection area and the number of nodes within in the communication range of a node. The output is a distance parameter which can represent the distance of neighbor nodes. We use the distances of anchor nodes and the distance parameter of neighbor nodes to calculate estimated distances between neighbor nodes. Then, we calculate the estimated positions of non-anchor nodes based on estimated distances and the MDS-MAP algorithm. Simulation results show that the localization error of the proposed algorithm is lower than the current range-free algorithms. Related Articles | Metrics

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Heart rate extraction algorithm based on ballistocardiogram Wang, Chun-Wu (1); Wang, Xu (1); Long, Zhe (1); Zhang, Ke-Xin (1) Journal of Northeastern University    2012, 33 (8): 1103-1106.   DOI: - Abstract （1920）   HTML    PDF （1465KB）（1949）       A novel algorithm was presented to extract heart rate from ballistocardiogram (BCG) signals more accurately. Original signals are pretreated by polynomial fitting and wavelet transform. Then priori heart rate is acquired through the spectrum analysis of unipolar signals and a local heartbeat cycle is divided into several subintervals based on the priori heart rate. Finally, the heart rate is obtained by threshold processing and local maximum value positioning. The BCG signals from 30 normal subjects were acquired, with their single-channel electrocardiogram (ECG) signals gathered synchronously. Compared the heart rate extracted from the BCG signals with that from ECG signals, the maximum relative error is only 1.78%, which verified the accuracy and feasibility of the proposed algorithm. Reference | Related Articles | Metrics

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Numerical simulation of the vacuum spray jet flow based on fluent analysis Li, Jian-Chang (1); Li, Hong-Yu (1); Han, Yu (1); Ba, De-Chun (1) Journal of Northeastern University    2012, 33 (3): 422-425.   DOI: - Abstract （1916）   HTML    PDF （1561KB）（1926）       This paper investigated the velocity and turbulence distribution of the cone nozzle jet flow field spraying into a vacuum chamber under different nozzle diameters and injection pressures. The simulations were carried out by using the Fluent software based on the volume of fluid method, the standard k-Ε turbulence model and the PISO (pressure implicit with splitting of operators) arithmetic. The results show that the jet flow and velocity gradient increase with increasing nozzle diameter, and it is helpful to improve jet spray quality with size uniform distribution after jet diffusion and drop breakup. When the nozzle diameter is constant, the jet turbulence intensity distribution achieves the optimum condition within 10~15 MPa, and the flow field is better than that under any other pressures. Compared with chloroform and carbon tetrachloride solvents, acetone shows better flow distribution and atmospheric effect if neglecting the solubility of the polymer materials. Reference | Related Articles | Metrics

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- - Journal of Northeastern University:Natural Science    1978, - (2): 104-113.   DOI: - Abstract （1849）   HTML    PDF （493KB）（1001）       - Reference | Related Articles | Metrics

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Extraction and Adsorption Properties of Extracellular Polymeric Substance XU Xiao-hui， WEI De-zhou， ZHANG Lan-he Journal of Northeastern University(Natural Science)    2021, 42 (10): 1467-1474.   DOI: 10.12068/j.issn.1005-3026.2021.10.014 Abstract （1823）   HTML （48）    PDF （1430KB）（706）       In order to quickly and efficiently extract extracellular polymeric substances(EPS)from activated sludge， four methods were used to extract tightly bound EPS(TB-EPS). The advantages and disadvantages of different extraction methods were compared， the effect of TB-EPS on the adsorption performance of Mn 2+was investigated， and the adsorption mechanism of TB-EPS was studied. The results show that the heating method is simple and efficient with no damage to cell structure.When adsorbing heavy metal Mn 2+， the maximum adsorption rate of TB-EPS extracted by heating method is 53.8%. The adsorption process conforms to the second-order reaction kinetic characteristics and the Langmuir adsorption isotherm equation， which is mainly the chemical adsorption. The main adsorption mechanism of TB-EPS is the interaction of hydrophobic tryptophan and tyrosin. Reference | Related Articles | Metrics

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CSP/SVM-based EEG classification of imagined hand movements Liu, Chong (1); Zhao, Hai-Bin (1); Li, Chun-Sheng (1); Wang, Hong (1) Journal of Northeastern University    2010, 31 (8): 1098-1101.   DOI: - Abstract （1817）   HTML    PDF （307KB）（2366）       For the BCI (brain-computer interface) to classify the different imagined movements of both left and right hands, the method of CSP (common spatial pattern) was used to extract the features of BCI 2003 competitive dataset. Then, the CSP based on a sliding time window was used to filter the EEG(electroencephalogram) data from the electrodes C3, Cz and C4, with the SVM (support vector machine) used as a classifier of the features. As a result, the highest accuracy of classification is 82.86% with the best classification time point 4.09 sec, maximum mutual information (MI) 0.47 bit and maximum MI steepness 0.431 bit/s. Compared to the results of BCI 2003 competition, the method as above can provide greatly improved maximum MI steepness, thus verifying that the method is more adaptable to what are required by the online BCI system. Reference | Related Articles | Metrics

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Analysis on Mechanical Properties of the Steel Plate Shear Wall with Fully Bolted and Welded Connections MU Zai-gen， DA Hai， YANG Yu-qing， WANG Zhe Journal of Northeastern University(Natural Science)    2021, 42 (3): 428-435.   DOI: 10.12068/j.issn.1005-3026.2021.03.019 Abstract （1811）   HTML （12）    PDF （5074KB）（333）       In order to avoid the residual stress caused by welding， the upper and lower steel plates are connected by the end-plate with bolts to form a fully bolted steel plate shear wall (SPSW) with better ductility and energy dissipation capacity. The models of fully bolted SPSW and welded SPSW were established and analyzed by the finite element method. The load-displacement curve， lateral bearing capacity， energy dissipation capacity， stiffness degradation， and bearing capacity degradation of the two kinds of steel plate shear walls under unidirectional push-over and reciprocating load were compared. The results show that， under the action of unidirectional push-over， the lateral bearing capacity of the SPSW with full bolted is close to that of the traditional form， but the initial stiffness is 11% lower than that of the traditional form. Under the reciprocating load， the SPSW with full bolted shows a better overall energy dissipation capacity， and the stiffness degrades slower. This form of SPSW is also convenient for production and installation， and worth to extensive promotion and application in the future engineering application. Reference | Related Articles | Metrics

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- - Journal of Northeastern University:Natural Science    1981, 2 (2): 16-22.   DOI: - Abstract （1764）   HTML    PDF （322KB）（1890）       - Reference | Related Articles | Metrics

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LMP calculation on PJM power market and its trial in China Zhang, Rui-You (1); Han, Shui (2); Zhang, Jin-Zhu (3); Wang, Ding-Wei (1) Journal of Northeastern University    2005, 26 (11): 16-18.   DOI: - Abstract （1677）   HTML    PDF （153KB）（6184）       For the pricing of power transmission/distribution in China, the PJM power market is introduced as a reference and studied, in which the locational marginal price (LMP) with no transmission loss taken into account is calculated according to the security constrained economic dispatch (SCED) based on de-power flow. To adapt the actual need, the constraints on the sum of transmitted power of multiple branches are added to the original PJM model, and the power transmission distributed factor (PTDF) matrix is proposed for branch sets. To test the efficiency of the proposed approach, a calculation trial has been done using a mathematical model of a 500 kV network. The results showed that the approach can provide correct signals to all parties on power market and manage well the costs due to congestion with the fixed transmission right (FTR) used together. Reference | Related Articles | Metrics