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Frontiers of Medicine 2020年第3期14卷 251-261页

作者： Li Jiang Deng Ning Xiao-ping Chen Department of Biliary and Pancreatic Surgery Tongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430030China Hepatic Surgery Center Tongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430030China

Postoperative pancreatic fistula (POPF) is the most common and critical complication after pancreatic body and tail resection.How to effectively reduce the occurrence of pancreatic fistula and conduct timely treatment thereafter is an urgent clinical issue to be solved.Recent research standardized the definition of pancreatic fistula and stressed the correlation between POPF classification and patient prognosis.According to the literature,identification of the risk factors for pancreatic fistula contributed to lowering the rate of the complication.Appropriate management of the pancreatic stump and perioperative treatment are of great significance to reduce the rate of POPF in clinical practice.After the occurrence of POPF,the treatment of choice should be determined according to the classification of the pancreatic fistula.However,despite the progress and promising treatment approaches,POPF remains to be a clinical issue that warrants further studies in the future.

关键词： pancreatic fistula pancreatic body and tail resection distal pancreatectomy

Effect of Axial Deformation on Elastic Properties of Irregular Honeycomb Structure

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Chinese Journal of Mechanical Engineering 2021年第4期34卷 276-287页

作者： ning Wang Qingtian deng School of Science Chang’an UniversityXi’an 710064China

Irregular honeycomb structures occur abundantly in nature and in man-made products,and are an active area of research.In this paper,according to the optimization of regular honeycomb structures,two types of irregular honeycomb structures with both positive and negative Poisson’s ratios are presented.The elastic properties of irregular honeycombs with varying structure angles were investigated through a combination of material mechanics and structural mechanics methods,in which the axial deformation of the rods was considered.The numerical results show that axial deformation has a significant influence on the elastic properties of irregular honeycomb structures.The elastic properties of the structure can be considered by the enclosed area of the unit structure,the shape of the unit structure,and the elastic properties of the original materials.The elastic properties considering the axial deformation of rods studied in this study can provide a reference for other scholars.

关键词： Axial deformation Elastic modulus Positive Poisson’s ratio Negative Poisson’s ratio Irregular honeycombs

LDM-Satellite:A New Scheme for Packet Loss Classification over LEO Satellite Network

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China Communications 2022年第12期19卷 207-215页

作者： ning Li Qiaodi Zhu Zhongliang deng School of Electronic Engineering Beijing University of Posts and TelecommunicationsBeijing 100876China

The packet loss classification has always been a hot and difficult issue in TCP congestion control research.Compared with the terrestrial network,the probability of packet loss in LEO satellite network increases dramatically.What’s more,the problem of concept drifting is also more serious,which greatly affects the accuracy of the loss classification model.In this paper,we propose a new loss classification scheme based on concept drift detection and hybrid integration learning for LEO satellite networks,named LDM-Satellite,which consists of three modules:concept drift detection,lost packet cache and hybrid integration classification.As far,this is the first paper to consider the influence of concept drift on the loss classification model in satellite networks.We also innovatively use multiple base classifiers and a naive Bayes classifier as the final hybrid classifier.And a new weight algorithm for these classifiers is given.In ns-2 simulation,LDM-Satellite has a better AUC(0.9885)than the single-model machine learning classification algorithms.The accuracy of loss classification even exceeds 98%,higher than traditional TCP protocols.Moreover,compared with the existing protocols used for satellite networks,LDM-Satellite not only improves the throughput rate but also has good fairness.

关键词： LEO Satellite Networ TCP congestion control concept drift detection ensemble learning loss classification

Finite-time path following control of a sailboat with actuator failure and unknown sideslip angle

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浙江大学学报(英文版)A辑:应用物理与工程 2023年第9期24卷 749-761页

作者： Yujin WU Kangjian SHAO ning WANG Zhongchao deng Science and Technology on Underwater Vehicle Laboratory Harbin Engineering UniversityHarbin 150001China School of Marine Engineering Dalian Maritime UniversityDalian 116026China

Suffering from actuator failure and complex sideslip angle,the motion control of a sailboat becomes challenging.In this paper,an improved double finite-time observer-based line-of-sight guidance and finite-time control(IDFLOS-FC)scheme is presented for path following of sailboats.The salient features of the proposed IDFLOS-FC scheme are as follows:(1)Considering the problem of actuator failure,an actuator failure model is introduced into the dynamics model of a sailboat.(2)The time-varying sideslip angle of the sailboat is accurately observed by the double finite-time sideslip observers(DFSOs),which reduces the error in line-of-sight(LOS)guidance.(3)A radial basis function(RBF)neural network is used to fit the uncertainty of the model,and the upper bound of the sum of fault effects and external disturbances is estimated based on adaptive theory,so that the controller has accurate tracking and interference suppression.(4)According to the Lyapunov method,the system is finite-time stable.Finally,simulation was used to validate the effectiveness of the method.

关键词： Sailboat Sideslip angle Sideslip angle observer Finite-time control(FC) Path following

Power Consumption Characteristics Research on Mobile System of Electrically Driven Large-Load-Ratio Six-Legged Robot

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Chinese Journal of Mechanical Engineering 2023年第1期36卷 237-267页

作者： Hongchao Zhuang ning Wang Haibo Gao Zongquan deng School of Mechanical Engineering Tianjin University of Technology and EducationTianjin300222China School of Information Technology Engineering Tianjin University of Technology and EducationTianjin300222China State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin150001China

The electrically driven large-load-ratio six-legged robot with engineering capability can be widely used in outdoor and planetary exploration.However,due to the particularity of its parallel structure,the effective utilization rate of energy is not high,which has become an important obstacle to its practical application.To research the power consumption characteristics of robot mobile system is beneficial to speed up it toward practicability.Based on the configuration and walking modes of robot,the mathematical model of the power consumption of mobile system is set up.In view of the tripod gait is often selected for the six-legged robots,the simplified power consumption model of mobile system under the tripod gait is established by means of reducing the dimension of the robot’s statically indeterminate problem and constructing the equal force distribution.Then,the power consumption of robot mobile system is solved under different working conditions.The variable tendencies of the power consumption of robot mobile system are respectively obtained with changes in the rotational angles of hip joint and knee joint,body height,and span.The articulated rotational zones and the ranges of body height and span are determined under the lowest power consumption.According to the walking experiments of prototype,the variable tendencies of the average power consumption of robot mobile system are respectively acquired with changes in duty ratio,body height,and span.Then,the feasibility and correctness of theory analysis are verified in the power consumption of robot mobile system.The proposed analysis method in this paper can provide a reference on the lower power research of the large-load-ratio multi-legged robots.

关键词： Electrically driven Large-load-ratio six-legged robot Power consumption Mobile system

Step-by-Step Numerical Prediction of Aerodynamic Noise Generated by High Speed Trains

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Chinese Journal of Mechanical Engineering 2022年第2期35卷 251-264页

作者： Tian Li deng Qin ning Zhou Weihua Zhang State Key Laboratory of Traction Power Southwest Jiaotong UniversityChengdu 610031China

In this paper,the unsteady flow around a high-speed train is numerically simulated by detached eddy simulation method(DES),and the far-field noise is predicted using the Ffowcs Williams-Hawkings(FW-H)acoustic model.The reliability of the numerical calculation is verified by wind tunnel experiments.The superposition relationship between the far-field radiated noise of the local aerodynamic noise sources of the high-speed train and the whole noise source is analyzed.Since the aerodynamic noise of high-speed trains is derived from its different components,a stepwise calculation method is proposed to predict the aerodynamic noise of high-speed trains.The results show that the local noise sources of high-speed trains and the whole noise source conform to the principle of sound source energy superposition.Using the head,middle and tail cars of the high-speed train as noise sources,different numerical models are established to obtain the far-field radiated noise of each aerodynamic noise source.The far-field total noise of high-speed trains is predicted using sound source superposition.A step-by-step calculation of each local aerodynamic noise source is used to obtain the superimposed value of the far-field noise.This is consistent with the far-field noise of the whole train model’s aerodynamic noise.The averaged sound pressure level of the far-field longitudinal noise measurement points differs by 1.92 dBA.The step-by-step numerical prediction method of aerodynamic noise of high-speed trains can provide a reference for the numerical prediction of aerodynamic noise generated by long marshalling high-speed trains.

关键词： High-speed train Aerodynamic noise Sound source superposition Numerical prediction

Sources,dynamics in vivo,and application of astaxanthin and lutein in laying hens:A review

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Animal Nutrition 2023年第2期13卷 324-333页

作者： Hanyi Shi Xuejuan deng Xiaoyu Ji ning Liu Huiyi Cai Department of Animal Science Henan University of Science and TechnologyLuoyang471023HenanChina Department of Poultry Science University of GeorgiaAthens30602GAUSA National Engineering Research Center of Biological Feed Beijing100081China

Astaxanthin(Ax)and lutein are important fat-soluble pigments and essential nutrients for human and animal health.Haematococcus pluvialis microalga and Phaffia rhodozyma yeast are ideal species for commercial Ax production.Marigold flowers are a main source of commercial lutein.Dynamics of dietary Ax and lutein in the gastrointestinal tract are similar to lipids,but their activities are tremendously challenged by many physiological and dietary factors;few data are available about these in poultry.Dietary Ax and lutein have insignificant effects on egg production and egg physical properties,but have pronounced effects on yolk color,nutrition,and functionality.The two pigments can also enhance antioxidative capacity and immune function of laying hens.A few studies have shown that Ax and lutein can improve fertilization and hatchability of laying hens.Considering the pigmentation and health benefits of Ax and lutein from hen feed to human food,the commercial availability,chicken yolk improvement,and immune function of Ax and lutein are the focuses of this review.The potential roles of carotenoids in the cytokine storm and gut microbiota are also briefly presented.The bioavailability,metabolism,and deposition of Ax and lutein in laying hens are suggested for future research.

关键词： Application Astaxanthin Egg yolk Food chain Laying hen Lutein

Predicting Credit Bond Default with Deep Learning: Evidence from China

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Journal of Social Computing 2024年第1期5卷 36-45页

作者： ning Zhang Wenhe Li Haoxiang Chen Binshu Jia Pei deng School of Information Central University of Finance and EconomicsBeijing 100081China SDIC Taikang Trust Co. Ltd.Beijing 100034China

China’s credit bond market has rapidly expanded in recent years.However,since 2014,the number of credit bond defaults has been increasing rapidly,posing enormous potential risks to the stability of the financial market.This study proposed a deep learning approach to predict credit bond defaults in the Chinese market.A convolutional neural network(CNN)was selected as the classification model and to reduce the extreme imbalance between defaulted and non-defaulted bonds,and a generative adversarial network(GAN)was used as the oversampling model.Based on 31 financial and 20 non-financial indicators,we collected Wind data on all credit bonds issued and matured or defaulted from 2014 to 2021.The experimental results showed that our GAN+CNN approach had superior predictive performance with an area under the curve(AUC)of 0.9157 and precision of 0.8871 compared to previous research and other commonly used classification models-including the logistic regression,support vector machine,and fully connected neural network models-and oversampling techniques-including the synthetic minority oversampling technique(SMOTE)and Borderline SMOTE model.For one-year predictions,indicators of solvency,capital structure,and fundamental properties of bonds are proved to be the most important indicators.

关键词： credit bond default prediction convolutional neural network imbalanced data processing generative adversarial network

A Modified Hadamard Based SLM without Side Information for PAPR Reduction in OFDM Systems

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China Communications 2019年第12期16卷 124-131页

作者： ning Li Mingjin Li Zhongliang deng School of Electronic Engineering Beijing University of Posts and Telecommunications

High peak-to-average power ratio(PAPR) is a concern in orthogonal frequency division multiplexing(OFDM) systems. Hadamard based selected mapping(HSLM) which uses Hadamard code as the phase sequence in selected mapping(SLM) is an attractive technique to reduce PAPR. But it requires sending side information(SI) to the receiver for each data block, and this results in a reduction in bandwidth efficiency. In this paper, we proposed a modified PAPR reduction method called semi-Hadamard based selected mapping(semi-HSLM) to decouple the phase information matrix into a phase rotation matrix for PAPR reduction and a SI matrix for side information hiding. We proposed a semi-hadamard matrix generation method to generate the phase rotation matrix, and designed a cyclic shift matrix as the SI matrix. Compared with the traditional HSLM, the semi-HSLM saves half of the phase storage and achieves good PAPR reduction performance.

关键词： OFDM PAPR SLM SI Hadamrd

Electro-magnetic interpretation of four-element torus

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Journal of Semiconductors 2017年第11期38卷 81-85页

作者： Wei Wu ning deng Institute of Microelectronics Tsinghua University Beijing 100084 China

The concept of the memristor was proposed by Leon Chua in 1971, along with some electro-magnetic interpretations according to quasi-static expansion of Maxwell＇s equations. In 2003, Chua included the memristor into a four-element torus that has infinite circuit elements. This paper uses the quasi-static method to interpret every circuit element in the torus. Two examples are also provided to show how topologic structure of an element affects its electrical properties by affecting the dominant electro-magnetic field components. Additionally, it is proved that the circuit elements in the torus, except the resistive, capacitive and inductive elements, cannot exist independently. Moreover, the incorrectness in Chua＇s interpretation of the memristor, that the memristor cannot be interpreted with the transient quasi-static method due to its memory property, is pointed out. Finally, the limitations of the electro-magnetic interpretation method are discussed.

关键词： electro-magnetic interpretation four-element torus memristor quasi-static expansion of Maxwell＇s equations