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Investigation of Model Ensemble for Fine-Grained Air Quality Prediction

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China Communications 2020年第7期17卷 207-223页

作者： Hong Zheng Yunhui Cheng haibin li Information Engineering and Computer Science College East China University of Science and TechnologyShanghai 200237China

Air pollution which is detrimental to people’s health is a wide spread problem across many countries around the *** better air quality prediction approaches is an important research *** methods often focus on the prediction of air pollution concentrations,which is not as intuitive to the public as the air quality *** this paper,near future fine-grained air quality level prediction task is explored with a series of machine learning ensemble *** ensemble methods are majority voting,averaging,weighted averaging and 16 different stacking *** investigate the performances of these ensemble methods,comprehensive comparative experiments are *** contrast models are classical Autoregressive Integrated Moving Average(ARIMA),popular deep learning model Long Short-Term Memory(LSTM)neural network,and nine of the base-level models such as Support Vector Machine(SVM),Random Forest(RF),Logistic Regression(LR)and several boosting *** acquired from a coastal city Hong Kong and an inland city Beijing are used to train and validate all the *** show that performances of the ensemble methods outperform most of the individual models,especially when stacking with probability distributions together with engineered original features,which demonstrates the best performance.

关键词： pollution LSTM ensemble

Towards real-time ML-based DDoS detection via cost-efficient window-based feature extraction

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Science China(Information Sciences) 2023年第5期66卷 114-129页

作者： haibin li Yi ZHAO Wenbing YAO Ke XU Qi li Department of Computer Science and Technology Tsinghua University Beijing National Research Center for Information Science and Technology (BNRist) Institute for Network Sciences and Cyberspace Tsinghua University

Distributed denial of service(DDoS) detection is still an open and challenging problem. In particular, sophisticated attacks, e.g., attacks that disguise attack packets as benign traffic always appear, which can easily evade traditional signature-based methods. Due to the low requirements for computing resources compared to deep learning, many machine learning(ML)-based methods have been realistically deployed to address this issue. However, most existing ML-based DDo S detection methods are highly dependent on the features extracted from each flow, which incur remarkable detection delay and computation overhead. This article investigates the limitations of typical ML-based DDo S detection methods caused by the extraction of flow-level features. Moreover, we develop a cost-efficient window-based method that extracts features from a fixed number of packets periodically, instead of per flow, aiming to reduce the detection delay and computation overhead. The newly proposed window-based method has the advantages of well-controlled overhead and wide support of common routers due to its simplicity and high efficiency by design. Through extensive experiments on real datasets, we evaluate the performance of flow-based and window-based *** experimental results demonstrate that our proposed window-based method can significantly reduce the detection delay and computation overhead while ensuring detection accuracy.

关键词： DDoS attack machine learning feature extraction detection delay cost-efficiency

Short communication Solvothermal synthesis of trigonal selenium with butterfly-like microstructure

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Particuology 2013年第5期11卷 614-617页

作者： Kai Zeng Shuguang Chen Yande Song haibin li Fujin li Peng liu School of Physics and Electronic Science Changsha University of Science & Technology

We present a facile synthesis of trigonal selenium with butterfly-like microstructure from elemental sele- nium via a solvothermal and aging route. By using X-ray diffraction and scanning electron microscopy to characterize the products, a possible growth mechanism is proposed. The solvothermal process pro- motes the dissolution of selenium in ethylenediamine to form a brown homogeneous [Se（en）x] solution. By introducing acetone into this [Se（en）x] solution, amorphous selenium nanoparticles were produced which then transformed into trigonal selenium, which further assembled along the c-axis to form hexag- onal rods. Owing to stereo hindrance as well as to development of opposite lateral sides of the hexagonal rod in opposing directions, a butterfly-like microstructure consisting of two long outside rods and a short inner rod was obtained.

关键词： SeleniumSolution-phaseButterfly-likeCrystal growthMicrostructure

Fractional Order Modeling of Human Operator Behavior with Second Order Controlled Plant and Experiment Research

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IEEE/CAA Journal of Automatica Sinica 2016年第3期3卷 271-280,279-280+272-278页

作者： Jiacai Huang Yang Quan Chen haibin li Xinxin Shi School of Automation Nanjing Institute of Technology IEEE School of Engineering University of California

Modeling human operator's dynamics plays a very important role in the manual closed-loop control system, and it is an active research area for several decades. Based on the characteristics of human brain and behavior, a new kind of fractional order mathematical model for human operator in single-input single-output (SISO) systems is proposed. Compared with the traditional models based on the commonly used quasilinear transfer function method or the optimal control theory method, the proposed fractional order model has simpler structure with only few parameters, and each parameter has explicit physical meanings. The actual data and experiment results with the second-order controlled plant illustrate the effectiveness of the proposed method. © 2014 Chinese Association of Automation.

关键词： Calculations Closed loop control systems Mathematical operators

Self-assembled gel-assisted preparation of high-performance hydrophobic PDMS@MWCNTs/PEDOT:PSS composite aerogels for wearable piezoresistive sensors

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Journal of Materials Science & Technology 2024年第15期182卷 22-32页

作者： haibin li Rubai Luo Jingbo Hu Kenan Yang Bin Du Shisheng Zhou Xing Zhou School of Mechanical and Precision Instrument Engineering Xi’an University of TechnologyXi’an 710048China Faculty of Printing Packaging Engineering and Digital Media TechnologyXi’an University of TechnologyXi’an 710048China Shanxi Key Laboratory of Advanced Manufacturing Technology North University of ChinaTaiyuan 038507China Shaanxi Provincial Key Laboratory of Printing and Packaging Engineering Xi’an University of TechnologyXi’an 710048China

The conductive polymer poly(3,4-thylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS)exhibits po-tential in the development of flexible devices due to its unique conjugated structure and water-solubility *** address the incompressibility of the original PEDOT:PSS aerogel without compromis-ing its high conductivity,a stable interpenetrating polymer network(IPN)was self-assembled by guiding the molecular motion within PEDOT:PSS and introducing multi-walled carbon nanotubes(MWCNTs).By combining critical surface removal,directional freeze-drying,and polydimethylsiloxane(PDMS)reinforce-ment processes,a hydrophobic PDMS@MWCNTs/PP aerogel with a highly oriented porous structure and high strength was *** the synergistic effect of MWCNTs/PEDOT:PSS electroactive scaffold,the composite aerogel exhibited a high sensitivity of up to 16.603 kPa^(-1) at 0-2 kPa,a fast response time of 74 ms,and excellent ***,the sensor possessed hydrophobicity with a good water contact angle of 137°The sensor could serve as a wearable electronic monitoring device to achieve ac-curate and sensitive detection of human motion including large-scale human activities and tiny muscle ***,our findings provide a new direction to fabricate high-performance piezoresistive sensors based on three-dimensional(3D)conductive polymer active scaffolds,demonstrating their great potential for flexible electronics,human-computer interaction,and a wide range of applications under special working conditions.

关键词： Pressure sensor PEDOT:PSS/MWCNTs hydrogel Composite aerogel Hierarchical porous structure Human motion detection

Influence of Rubber Powder Movement on Properties of Asphalt Rubber from the Mesoscopic View

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Journal of Wuhan University of Technology(Materials Science) 2023年第2期38卷 312-324页

作者： li haibin HU Yihong SHI Xuan ZHANG Mingming ZHAO Guijuan ZOU Xiaolong SENG Yanping School of Architecture and Civil Engineering Xi’an University of Science and TechnologyXi’an710054China Road Engineering Research Center Xi’an University of Science and TechnologyXi’an710054China School of Material Science and Engineering Chang’an UniversityXi’an710064China

The research on asphalt performance mainly focused on the macro performance and micro *** analysis was introduced to study the effect of rubber powder movement on asphalt rubber *** the preparation parameters and the preparation process of asphalt rubber were determined,the modification mechanism and rheological properties were analyzed which revealed the compatible stability ***,the analysis model of asphalt rubber was established to focus on simulating the effect of rubber powder and the spatial movement on its mechanical *** experimental results show that rubber powder can make the asphalt rubber bear more uniform stress distribution and enhance the ability to resist ***,the rotational motion and final distribution of rubber powder have an obvious impact on the mechanical properties of asphalt *** the selected feature points,the average stress of rubber powder at 0°space angle is only 34.1%of that at90°space *** the rubber powders are all in parallel in the ideal state,it enhances the mechanical properties the *** study supplements the“mesoscopic”scale between macro and micro *** relationship between micro mechanism and macro properties of asphalt rubber will be established from the mesoscopic *** is also an effort to realize the effective correlation from micro,mesoscopic to macro in asphalt.

关键词： asphalt rubber rubber powder movement space angle of rubber powder mesoscopic scale numerical simulation

Chemical-Looping Reforming of Methane Using Iron Based Oxygen Carrier Modified with Low Content Nickel

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Chinese Journal of Chemistry 2014年第12期32卷 1271-1280页

作者： Guoqiang Wei Fang He Zhen Huang Kun Zhao Anqing Zheng haibin li CAS Key Laboratory of Renewable Energy Guangzhou Institute of Energy ConversionChinese Academy of SciencesGuangzhouGuangdong 510640China

Fe_(2)O_(3)/Al_(2)O_(3) and Fe_(2)O_(3)/Al_(2)O_(3) modified by low content of Ni(below 2%in weight)oxygen carriers were prepared by mechanical mixing and impregnation *** synthesized oxygen carriers were characterized by means of X-ray diffraction(XRD),X-ray fluorescence(XRF),scanning electron microscopy(SEM),BET-surface area and temperature programmed reduction(TPR).Besides,redox cyclic reactivity and the performance of chemical looping reforming of methane of the oxygen carriers were studied in a thermal gravimetrical analysis(TGA)and fixed bed at 850℃.It was observed that the redox reactivity of the oxygen carriers is improved by Ni addition because synergic effect may occur between NiO and Fe_(2)O_(3)/Al_(2)O_(3) to form NiFe_(2)O_(4) and NiAl_(2)O_(4) spinel ***,the improvement was not apparent as Ni addition reached 1 wt%or more because more nickel loaded resulted in methane decomposition into H2 and carbon leading to carbon *** SEM and BET analysis showed that NiFe_(2)O_(4) and NiAl_(2)O_(4) particles dispersed into the pores of the Fe_(2)O_(3)/Al_(2)O_(3) particles in the course of *** addition,the resistance to sintering of the modified samples increased with the Ni addition *** results of successive redox cycles showed that the Ni modified Fe_(2)O_(3)/Al_(2)O_(3) oxygen carriers have good *** integration of reactivity and carbon deposition,the content 1.04 wt%of nickel doping was an optimal amount in the three modified samples.

关键词： methane chemical-looping reforming chemical-looping reforming oxygen carrier iron low content nickel

Depth recovery for unstructured farmland road image using an improved SIFT algorithm

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International Journal of Agricultural and Biological Engineering 2019年第4期12卷 141-147页

作者： lijian Yao Dong Hu Zidong Yang haibin li Mengbo Qian School of Engineering Zhejiang A&F UniversityHangzhou 311300China

Road visual navigation relies on accurate road *** study was aimed at proposing an improved scale-invariant feature transform(SIFT)algorithm for recovering depth information from farmland road images,which would provide a reliable path for visual *** mean image of pixel value in five channels(R,G,B,S and V)were treated as the inspected image and the feature points of the inspected image were extracted by the Canny algorithm,for achieving precise location of the feature points and ensuring the uniformity and density of the feature *** mean value of the pixels in 5×5 neighborhood around the feature point at an interval of 45ºin eight directions was then treated as the feature vector,and the differences of the feature vectors were calculated for preliminary matching of the left and right image feature *** order to achieve the depth information of farmland road images,the energy method of feature points was used for eliminating the mismatched *** with a binocular stereo vision system were conducted and the results showed that the matching accuracy and time consuming for depth recovery when using the improved SIFT algorithm were 96.48%and 5.6 s,respectively,with the accuracy for depth recovery of-7.17%-2.97%in a certain sight *** mean uniformity,time consuming and matching accuracy for all the 60 images under various climates and road conditions were 50%-70%,5.0-6.5 s,and higher than 88%,respectively,indicating that performance for achieving the feature points(e.g.,uniformity,matching accuracy,and algorithm real-time)of the improved SIFT algorithm were superior to that of conventional SIFT *** study provides an important reference for navigation technology of agricultural equipment based on machine vision.

关键词： scale-invariant feature transform(sift) feature matching canny operator energy method of feature point farmland road depth recovery visual navigation

Constraints of palaeoenvironment on organic matter of Benxi Formation shale and discussion on enrichment mechanism under different facies

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Frontiers of Earth Science 2024年第1期18卷 148-171页

作者： Qianyang HE Delu li Qiang SUN Jianwen GAO haibin li Xinhu li Xiaochen ZHAO Shaofei WANG Gaozhe JI College of Geology and Environment Xi’an University of Science and TechnologyXi’an 710054China Shaanxi Provincial Key Laboratory of Geological Support for Coal Green Exploitation Xi’an University of Science and TechnologyXi’an 710054China Geological Research Institute for Coal Green Mining Xi’an University of Science and TechnologyXi’an 710054China Research Institute of Exploration and Development PetroChina Changqing Oilfield CompanyXi’an 710018China School of Civil Engineering and Architecture Shaanxi University of TechnologyHanzhong 723001China

As a hydrocarbon-rich sedimentary basin in China,the Ordos Basin has enormous potential for shale gas *** shale of the Upper Carboniferous Benxi Formation is rich in organic matter,however,its palaeoenvironment and organic matter enrichment mode are yet to be *** this study,the geochemical characteristics of the shale of the Benxi Formation in the east-central part of the Ordos Basin were analyzed to investigate its *** the same time,the organic matter enrichment modes in different sedimentary facies were compared and *** results indicate that:1)the shale of the Benxi Formation was mainly deposited on the continental margin and strong terrestrial clastic input;2)the deposition period of the Benxi Formation shale had a hot and humid climate with high palaeoproductivity and local volcanic hydrothermal fluid,and a high sedimentation rate with the strong stagnant *** bottom water was in dysoxic conditions and a semi-saline deposition environment;3)multiple factors,such as palaeoproductivity,volcanic hydrothermal,redox conditions,and palaeosalinity interact to influence the enrichment of shale organic matter in Benxi Formation;4)the organic matter enrichment modes of continental,marine-continental transitional,and marine shales can be classified into three types:“production mode”,“hybrid mode of preservation and production”,and“preservation mode”,*** study provides a reference for the organic matter enrichment mode,shale gas formation conditions,and core area evaluation in these marine-continental transitional shales,and also offers new guidance for exploration ideas for shale gas in different sedimentary facies.

关键词： Benxi Formation shale palaeoenvironment organic matter enrichment facies