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Automated String Constraints Solving for Programs Containing String Manipulation Functions

Journal of Computer Science & Technology 2017年第6期32卷 1125-1135页

作者： xu-zhou zhang Yun-Zhan Gong Ya-Wen Wang Ying Xing Ming-Zhe zhang State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing 100876 China Automation School Beijing University of Posts and Telecommunications Beijing 100876 China

The ability to solve various constraints is a principal factor of automatic constraint solvers. Most object-oriented languages treat a character string as a primitive data type which is manipulated by string library functions. Most constraint solvers have limitations on their input constraints, such as strong restrictions on the expressiveness of constraints or lack of the ability to solve hybrid constraints. These limitations hinder applying automated constraint solvers on program analysis techniques for programs containing strings and string manipulation functions. We propose an approach to automatically solve program constraints involving strings and string manipulation functions. Based on the character array model, we design a constraint language which contains primitive operations to precisely describe the constraints of commonly used string manipulation functions. The translated string constraints together with numeric constraints are then solved by a two- phase test generation procedure： firstly, a partial solution is obtained to satisfy the arithmetic constraints of the position variables, and the solution is utilized to simplify the string constraints into pure character array constraints; secondly, the pure array constraints are solved by an off-the-shelf array-specific theory based constraint solver. We integrate the approach into an automated testing tool to support the generation of string test cases, and then perform experiments. The results of the experiments prove that the integration of the proposed approach promotes the testing coverage of the existing testing tool, and the integrated tool has an advantage of handling specific string manipulation functions compared with an existing string solver.

关键词： string constraints solving satisfaction module theory program analysis software testing automated testinput generation

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Image-Based Flow Prediction of Vocal Folds Using 3D Convolutional Neural Networks

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Journal of Bionic Engineering 2024年第2期21卷 991-1002页

作者： Yang zhang Tianmei Pu Jiasen xu Chunhua zhou College of Astronautics Nanjing University of Aeronautics and AstronauticsNanjing210016China College of Electrical Energy and Power EngineeringYangzhou UniversityYangzhou225127China College of Aeronautics Nanjing University of Aeronautics and AstronauticsNanjing210016China

In this work,a three dimensional(3D)convolutional neural network(CNN)model based on image slices of various normal and pathological vocal folds is proposed for accurate and efficient prediction of glottal *** 3D CNN model is composed of the feature extraction block and regression *** feature extraction block is capable of learning low dimensional features from the high dimensional image data of the glottal shape,and the regression block is employed to flatten the output from the feature extraction block and obtain the desired glottal flow *** input image data is the condensed set of 2D image slices captured in the axial plane of the 3D vocal folds,where these glottal shapes are synthesized based on the equations of normal vibration *** output flow data is the corresponding flow rate,averaged glottal pressure and nodal pressure distributions over the glottal *** 3D CNN model is built to establish the mapping between the input image data and output flow *** ground-truth flow variables of each glottal shape in the training and test datasets are obtained by a high-fidelity sharp-interface immersed-boundary *** proposed model is trained to predict the concerned flow variables for glottal shapes in the test *** present 3D CNN model is more efficient than traditional Computational Fluid Dynamics(CFD)models while the accuracy can still be retained,and more powerful than previous data-driven prediction models because more details of the glottal flow can be *** prediction performance of the trained 3D CNN model in accuracy and efficiency indicates that this model could be promising for future clinical applications.

关键词： Vocal folds Computational fluid dynamics Machine learning 3D convolutional neural network

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Unsaturated bi-heterometal clusters in metal-vacancy sites of 2D MoS2 for efficient hydrogen evolution

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Carbon Energy 2024年第3期6卷 264-275页

作者： Gonglei Shao Jie xu Shasha Gao zhang zhang Song Liu xu zhang Zhen zhou Interdisciplinary Research Center for Sustainable Energy Science and Engineering(IRC4SE2) School of Chemical EngineeringZhengzhou UniversityZhengzhouHenanChina College of Chemistry and Materials Engineering Wenzhou UniversityWenzhouZhejiangChina Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education) College of ChemistryNankai UniversityTianjinChina State Key Laboratory of Chemo/Biosensing and Chemometrics Institute of Chemical Biology and Nanomedicine(ICBN)College of Chemistry and Chemical EngineeringHunan UniversityChangshaHunanChina Institute of New Energy Material Chemistry School of Materials Science and EngineeringNankai UniversityTianjinChina

The valence states and coordination structures of doped heterometal atoms in two-dimensional(2D)nanomaterials lack predictable regulation ***,a robust method is proposed to form unsaturated heteroatom clusters via the metal-vacancy restraint mechanism,which can precisely regulate the bonding and valence state of heterometal atoms doped in 2D molybdenum *** unsaturated valence state of heterometal Pt and Ru cluster atoms form a spatial coordination structure with Pt–S and Ru–O–S as catalytically active *** them,the strong binding energy of negatively charged suspended S and O sites for H+,as well as the weak adsorption of positively charged unsaturated heterometal atoms for H*,reduces the energy barrier of the hydrogen evolution reaction proved by theoretical ***,the electrocatalytic hydrogen evolution performance is markedly improved by the ensemble effect of unsaturated heterometal atoms and highlighted with an overpotential of 84 mV and Tafel slope of 68.5 mV dec^(−1).In brief,this metal vacancy-induced valence state regulation of heterometal can manipulate the coordination structure and catalytic activity of heterometal atoms doped in the 2D atomic lattice but not limited to 2D nanomaterials.

关键词： clusters hydrogen evolution reaction metal vacancy MoS2 unsaturated heterometal

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Dynamic impedance of piles in visco-elastic material considering axial loads

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Journal of Central South University of Technology 2005年第z1期12卷 162-167页

作者： JIANG Jian-guo zhou xu-hong zhang Jia-sheng School of Civil Engineering and Architecture Central South University Changsha 410075 China School of Civil Engineering and Architecture Chang''an University Xi''an 710064 China School of Civil Engineering and Architecture Central South University Changsha 410075 China

The dynamic impedance function of pile in visco-elastie material considering axial loads under lateral dynamic force was analyzed, and the beam dynamic differential equation was used to induce the dynamic impedance function. After analyzing the edge conditions, the dynamic impedance functions were deduced. Contrasted with the result that does not consider axial loads, the axial loads have obvious influence on the dynamic impedance *** the results show that the dimensionless prarmeter of the dynamic impedance will change from 6 % to 9 % when considering axial loads, and dimensionless prarmeter of the dynamic impedance of the coupling horizontal-sway will increase by 31 %.

关键词： impedance function dynamic analysis axial loads

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An initial investigation of the non-isotropic feature of GNSS tropospheric delay

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Satellite Navigation 2024年第1期5卷 155-167页

作者： Ying xu Zaozao Yang Hongzhan zhou Fangzhao zhang College of Geodesy and Geomatics Shandong University of Science and Technology579 Qianwangang RoadQingdao266590ShandongChina

Tropospheric delay is a significant error source in Global Navigation Satellite Systems(GNSS)*** Path Delay(SPD)is commonly derived by multiplying Zenith Tropospheric Delay(ZTD)with a mapping ***,mapping functions,assuming atmospheric isotropy,restrict the accuracy of derived *** improve the accuracy,a horizontal gradient correction is introduced to account for azimuth-dependent SPD variations,treating the atmosphere as *** study uncovers that,amidst atmospheric dynamics and spatiotemporal changes in moisture content,the SPD deviates from that based on traditional isotropy or anisotropy *** innovatively introduces the concept that SPD exhibits non-isotropy with respect to azimuth *** validation involves assessing SPD accuracy using three mapping functions at five International GNSS Service(IGS)stations,referencing the SPD with the ray-tracing *** subsequently evaluates the SPD accuracy with horizontal gradient correction based on Vienna Mapping Function 3(VMF3)***,the non-isotropic of SPD is analyzed through the ray-tracing *** results indicate the smallest residual(1.1–82.7 mm)between the SPDs with VMF3 and those with the ***,introducing horizontal gradient correction yields no significant improvement of SPD *** potential decimeter-level differences in SPD due to non-isotropic tropospheric delay across azimuth angles,a precise grasp and summary of these variations is pivotal for accurate tropospheric delay *** finding provides vital support for future high-precision tropospheric delay modeling.

关键词： Tropospheric delay GNSS Non-isotropy Mapping function Ray-tracing Horizontal gradient ERA5

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Modeling and Validation of Diamagnetic Rotor Levitated by Permanent Magnetics

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Chinese Journal of Mechanical Engineering 2024年第3期37卷 224-235页

作者： Yuanping xu Yue zhang Jin zhou Chaowu Jin College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

As an innovative,low-power consuming,and low-stiffness suspension approach,the diamagnetic levitation technique has attracted considerable interest because of its potential applicability in miniaturized mechanical *** foundation of a diamagnetic levitation system is mathematical modeling,which is essential for operating performance optimization and stability ***,few studies on systematic mathematical modeling have been *** this study,a systematic mathematical model for a disc-shaped diamagnetically levitated rotor on a permanent magnet array is *** on the proposed model,the magnetic field distribution characteristics,diamagnetic levitation force characteristics(i.e.,levitation height and stiffness),and optimized theoretical conditions for realizing stable levitation are *** are conducted to verify the feasibility of the proposed mathematical *** predictions and experimental results indicate that increasing the levitation height enlarges the stable ***,with a further increase in the rotor radius,the stable regions of the rotor gradually diminish and even ***,when the levitation height is fixed,a moderate rotor radius permits stable *** study proposes a mathematical modeling method for a diamagnetic levitation system that has potential applications in miniaturized mechanical systems.

关键词： Diamagnetic levitation Magnetic levitation Rotor Modeling Validation Stability

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Microwave irradiation-induced alterations in physicochemical properties and methane adsorption capability of coals:An experimental study using carbon molecular sieve

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Chinese Journal of Chemical Engineering 2024年第4期68卷 165-180页

作者： xuexiang Fu Xing Tang Yi xu Xintao zhou Dengfeng zhang Faculty of Chemical Engineering Kunming University of Science and TechnologyKunming 650500China

In order to comprehend the applicability of microwave irradiation for recovering coalbed methane,it is necessary to evaluate the microwave irradiation-induced alterations in coals with varying levels of *** this work,the carbon molecular sieve combined with KMnO_(4)oxidation was selected to fabricate carbon molecular sieve with diverse oxidation degrees,which can serve as model substances toward ***,the microwave irradiation dependences of pores,functional groups,and highpressure methane adsorption characteristics of model substances were *** results indicated that microwave irradiation causes rearrangement of oxygen-containing functional groups,which could block the micropores with a size of 0.40-0.60 nm in carbon molecular sieve;meanwhile,naphthalene and phenanthrene generated by macro-molecular structure pyrolysis due to microwave irradiation could block the micropores with a size of 0.70-0.90 *** alterations in micropore structure weaken the saturated methane adsorption capacity of oxidized carbon molecular sieve by 2.91%-23.28%,suggesting that microwave irradiation could promote methane ***,the increased mesopores found for oxidized carbon molecular sieve after microwave irradiation could benefit CH4 *** summary,the oxidized carbon molecular sieve can act as model substances toward coals with different ***,microwave irradiation is a promising technology to enhance coalbed methane recovery.

关键词： Microwave irradiation Physicochemical property Coal matrix Adsorption Carbon molecular sieve

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Iodine enrichment in the groundwater in South China and its hydrogeochemical control

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Journal of Environmental Sciences 2024年第8期142卷 226-235页

作者： Fengping zhou Qianting xu Yuyun Chen Weihua zhang Rongliang Qiu Guangdong Provincial Key Laboratory of Environmental Pollution and Remediation Technology Guangdong Provincial Engineering Research Center for Heavy Metal Contaminated Soil RemediationSchool of Environmental Science and EngineeringSun Yat-sen UniversityGuangzhou 510275China Shenzhen Research Institute Sun Yat-sen UniversityShenzhen 518057China Guangdong Provincial Key Laboratory of Agricultural&Rural Pollution Abatement and Environmental Safety School of Natural Resources and EnvironmentSouth China Agricultural UniversityGuangzhou 510642China Guangdong Laboratory for Lingnan Modern Agriculture Guangzhou 510642China

In North China,iodine-rich groundwater has been extensively studied,but few in South *** study aimed to investigate the characteristics of iodine-rich groundwater in South China and identify potential contamination *** results revealed that the average concentration of iodine in groundwater was 890μg/L,with a maximumconcentration of 6350μg/L,exceeding the permitted levels recommended by the World Health Organization(5–300μg/L).Notably,the enrichment of iodide occurred in acidic conditions(pH=6.6)and a relatively low Eh environment(Eh=198.4 mV).Pearson correlation and cluster analyses suggested that the enrichment of iodide could be attributed to the intensified redox process involving Mn(II),iodine(I_(2)),or iodate(IO_(3)^(−))in the *** strong affinity between Mn(II)and I_(2)/IO_(3)^(−)facilitated their interaction,resulting in the formation and mobilization of I^(−)from the soil to the *** experiments further confirmed that reducing substances(such as sodium sulfides,ascorbic acids,and fulvic acids)in the soil with low dissolved oxygen(DO)levels(3.8 mg/L)promoted the oxidation of I^(−)into I_(2)or IO_(3)^(−),leading to its *** research provides new insights into the characteristics and mechanisms of I^(−)enrichment in groundwater in South China,and emphasizes the significance of the redox reactions involving Mn(II)and I_(2)/IO_(3)^(−),as well as the influence of soil properties in regulating the occurrence and transportation of iodine species within groundwater systems.

关键词： Iodine enrichment Acid environment Groundwater South China Manganese

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A New High-Precision and Lightweight Detection Model for Illegal Construction Objects Based on Deep Learning

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Tsinghua Science and Technology 2024年第4期29卷 1002-1022页

作者： Wenjin Liu Lijuan zhou Shudong zhang Ning Luo Min xu School of Cyberspace Security(School of Cryptology) Hainan UniversityHaikou 570228China School of Information Engineering Capital Normal UniversityBeijing 100048China

Illegal construction has caused serious harm around the world. However, current methods are difficult to detect illegal construction activities in time, and the calculation complexity and the parameters of them are large. To solve these challenges, a new and unique detection method is proposed, which detects objects related to illegal buildings in time to discover illegal construction activities. Meanwhile, a new dataset and a high-precision and lightweight detector are proposed. The proposed detector is based on the algorithm You Only Look Once (YOLOv4). The use of DenseNet as the backbone of YDHNet enables better feature transfer and reuse, improves detection accuracy, and reduces computational costs. Meanwhile, depthwise separable convolution is employed to lightweight the neck and head to further reduce computational costs. Furthermore, H-swish is utilized to enhance non-linear feature extraction and improve detection accuracy. Experimental results illustrate that YDHNet realizes a mean average precision of 89.60% on the proposed dataset, which is 3.78% higher than YOLOv4. The computational cost and parameter count of YDHNet are 26.22 GFLOPs and 16.18 MB, respectively. Compared to YOLOv4 and other detectors, YDHNet not only has lower computational costs and higher detection accuracy, but also timely identifies illegal construction objects and automatically detects illegal construction activities.

关键词： object detection lightweight illegal buildings illegal construction objects high-precision

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Comparative evaluation of SPE methods for biotoxicity assessment of water and wastewater:Linkage between chemical extracting efficiency and biotoxicity outcome

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Journal of Environmental Sciences 2024年第8期142卷 33-42页

作者： Jiawei zhou Shihao Wang Xiwei He Hongqiang Ren xu-Xiang zhang State Key Laboratory of Pollution Control and Resource Reuse School of EnvironmentNanjing UniversityNanjing 210023China

Biotoxicity assessment results of environmental waters largely depend on the sample extraction protocols that enrich pollutants to meet the effect-trigger thresholds of ***,more chemical mixture does not necessarily translate to higher combined ***,there is a need to establish the link between chemical extracting efficiency and biotoxicity outcome to standardize extraction methods for biotoxicity assessment of environmental *** study compares the performance of five different extraction phases in solid phase extraction(SPE),namely HLB,HLB+Coconut,C18 cartridge,C18 disk and Strata-X,and evaluated their chemical extracting efficiencies and biotoxicity *** quantitatively assessed cytotoxicity,acute toxicity,genotoxicity,estrogenic activity,and neurotoxicity of the extracts using in vitro bioassays and characterized the chemical extracting efficiencies of the SPE methods through chemical recoveries of 23 model compounds with different polarities and total organic *** Pareto ranking,we identified HLB+Coconut as the optimal SPE method,which exhibited the highest level of water sample biotoxicity and recovered the most chemicals in water *** found that the biotoxicity outcomes of the extracted water samples significantly and positively correlated with the chemical extracting efficiencies of the SPE ***,we observed synchronous changing patterns in biotoxicity outcome and chemical extracting efficiencies in response to increasing sample volumes per cartridge(SVPC)during *** findings underscore that higher chemical extracting efficiency of SPE corresponds to higher biotoxicity outcome of environmental water samples,providing a scientific basis for standardization of SPE methods for adequate assessment of biotoxicities of environmental waters.

关键词： Biotoxicity Chemical recovery Solid phase extraction Surface water Wastewater

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