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An Innovative Deep Architecture for Flight Safety Risk Assessment Based on Time Series Data

Computer Modeling in Engineering & Sciences 2024年第3期138卷 2549-2569页

作者： Hong Sun Fangquan Yang Peiwen Zhang Yang Jiao yunxiang zhao Civil Aviation Flight Technology and Flight Safety Research Base Civil Aviation Flight University of ChinaGuanghan618307China Airport Academy Civil Aviation Flight University of ChinaGuanghan618307China School of Economics and Management Civil Aviation Flight University of ChinaGuanghan618307China China Academy of Civil Aviation Science and Technology Beijing101300China Flight Training Standards Branch Civil Aviation Flight University of ChinaGuanghan618307China

With the development of the integration of aviation safety and artificial intelligence,research on the combination of risk assessment and artificial intelligence is particularly important in the field of risk management,but searching for an efficient and accurate risk assessment algorithm has become a challenge for the civil aviation industry.Therefore,an improved risk assessment algorithm(PS-AE-LSTM)based on long short-term memory network(LSTM)with autoencoder(AE)is proposed for the various supervised deep learning algorithms in flight safety that cannot adequately address the problem of the quality on risk level labels.Firstly,based on the normal distribution characteristics of flight data,a probability severity(PS)model is established to enhance the quality of risk assessment labels.Secondly,autoencoder is introduced to reconstruct the flight parameter data to improve the data quality.Finally,utilizing the time-series nature of flight data,a long and short-termmemory network is used to classify the risk level and improve the accuracy of risk assessment.Thus,a risk assessment experimentwas conducted to analyze a fleet landing phase dataset using the PS-AE-LSTMalgorithm to assess the risk level associated with aircraft hard landing events.The results show that the proposed algorithm achieves an accuracy of 86.45%compared with seven baseline models and has excellent risk assessment capability.

关键词： Safety engineering risk assessment time series data autoencoder LSTM

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General synthesis of transition metal nitride arrays by ultrafast flash Joule heating within 500 ms

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Science China Chemistry 2024年第6期67卷 1976-1982页

作者： Peiqi Shen Jiahui zhao Yanan Gao yunxiang Lin Yuchen Han Kun Xu School of Chemistry and Chemical Engineering Key Laboratory of Functional Inorganic Material Chemistry of Anhui ProvinceAnhui Province Key Laboratory of Chemistry for Inorganic/Organic Hybrid Functionalized MaterialsKey Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of EducationAnhui UniversityHefei230601China Institutes of Physical Science and Information Technology Center of Free Electron Laser&High Magnetic FieldLeibniz International Joint Research Center of Materials Sciences of Anhui ProvinceAnhui UniversityHefei230601China

Transition metal nitrides(TMNs)are considered as viable alternatives to noble metal catalysts owing to their versatile electronic structure and favorable catalytic performance.However,the conventional synthetic processes for TMNs suffer from high energy consumption and low production yield.In this study,a range of TMNs and their hetero-composite arrays were successfully synthesized via an ultrafast flash Joule heating technology within 0.5 s.As a proof concept,the nitrides and hetero-composites were applied for the electrocatalytic hydrazine oxidation reaction(HzOR),in which the Co_(4)N/Mo_(16)N_(7)arrays shows the best performance with a geometric current density of 100 mA cm^(-2)at 23 mV(vs.reversible hydrogen electrode(RHE)).This work paves a new way for the ultrafast synthesis of TMNs which could meet the ever-increased energy crisis.

关键词： flash Joule heating rapid synthesis transition metal nitrides hydrazine oxidation reaction electrocatalysts

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A 28/56 Gb/s NRZ/PAM-4 dual-mode transceiver with 1/4 rate reconfigurable 4-tap FFE and half-rate slicer in a 28-nm CMOS

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Journal of Semiconductors 2024年第6期45卷 35-46页

作者： Yukun He zhao Yuan Kanan Wang Renjie Tang yunxiang He Xian Chen Zhengyang Ye Xiaoyan Gui School of Microelectronics Xi’an Jiaotong UniversityXi’an 710049China

A 28/56 Gb/s NRZ/PAM-4 dual-mode transceiver(TRx)designed in a 28-nm complementary metal-oxide-semiconduc-tor(CMOS)process is presented in this article.A voltage-mode(VM)driver featuring a 4-tap reconfigurable feed-forward equal-izer(FFE)is employed in the quarter-rate transmitter(TX).The half-rate receiver(RX)incorporates a continuous-time linear equal-izer(CTLE),a 3-stage high-speed slicer with multi-clock-phase sampling,and a clock and data recovery(CDR).The experimen-tal results show that the TRx operates at a maximum speed of 56 Gb/s with chip-on board(COB)assembly.The 28 Gb/s NRZ eye diagram shows a far-end vertical eye opening of 210 mV with an output amplitude of 351 mV single-ended and the 56 Gb/s PAM-4 eye diagram exhibits far-end eye opening of 33 mV(upper-eye),31 mV(mid-eye),and 28 mV(lower-eye)with an output amplitude of 353 mV single-ended.The recovered 14 GHz clock from the RX exhibits random jitter(RJ)of 469 fs and deterministic jitter(DJ)of 8.76 ps.The 875 Mb/s de-multiplexed data features 593 ps horizontal eye opening with 32.02 ps RJ,at bit-error rate(BER)of 10-5(0.53 UI).The power dissipation of TX and RX are 125 and 181.4 mW,respectively,from a 0.9-V sup-ply.

关键词： transceiver(TRx) feed-forward equalizer(FFE) clock and data recovery(CDR) continuous time linear equalizer(CTLE)

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Optimization of fracturing parameters for tight oil production based on genetic algorithm

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Petroleum 2022年第2期8卷 252-263页

作者： Dali Guo Yunwei Kang Zhiyong Wang yunxiang zhao Shuguang Li School of Science Southwest Petroleum UniversityChengdu610500China Engineering Technology Research Institute of XDEC Karamay834000China School of Science Civil Aviation Flight University of ChinaDeyang618000China China United Coalbed Methane National Engineering Research Center Co. Ltd.Beijing100095China

It is difficult to determine the main controlling factors of tight oil production.In addition to the problem of uncontrollable prediction accuracy,the numerical prediction model established by the main controlling factors will also make the correctly predicted low production samples lose the value of development.Applying the optimization algorithm with fast convergence speed and global optimization to optimize the controllable parameters in the high-precision numerical prediction model can effectively improve the productivity of low production wells with timeliness,and bring greater economic value while saving development cost.Using PCA-GRA method,the sample weight and the weighted correlation ranking results of parameters affecting tight oil production were obtained.Thereupon then the main controlling factors of tight oil production were determined.Then we set up a BP neural network model with by taking the main controlling factors as input and tight oil production as output.The prediction effect of the network was good and can be put into use.The results of sensitivity analysis showed that the network was stable,and the total fracturing fluid volume had the greatest impact on the production of tight oil.Finally,by using genetic algorithm,we optimized the fracturing parameters of all low production well samples in the field data.Combined with the fracturing parameters of all high production well samples and the optimized fracturing parameters of low production wells,the optimal interval of fracturing parameters was given,which can provide guidance for the field fracturing operation.

关键词： PCA-GRA method Main controlling factors BP neural network Genetic algorithm Optimization of fracturing parameters

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Optimization design of multi-gathering mode for the surface system in coalbed methane field

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Petroleum 2023年第2期9卷 237-247页

作者： Jun Zhou Tiantian Fu Kunyi Wu yunxiang zhao Lanting Feng Petroleum Engineering School Southwest Petroleum UniversityChengduChina Research Institute of Gathering and Transportation Engineering Technology PetroChina Southwest Oil&Gas Field CompanyChengduChina Pipechina Southwest Pipeline Company ChengduChina

As a potential resource for emerging clean energy with abundant reserves,coalbed methane(CBM)has risen rapidly in recent years,and the construction of rational and economical CBM gathering system plays a vital role in the development of the oil and gas industry.At present,there is no literature that considers the optimization of the multi-gathering mode of coalbed methane pipe network system.Due to the complexity and high investment,this paper establishes a unified mixed-integer nonlinear programming model to determine the gathering modes(including liquified natural gas,compressed natural gas,and gas gathering station)of gathering system to reduce the cost of coalbed methane collection and export.The objective function is the maximization of total profit during the period of the whole project,and such constraints,like network structure,facility number,location,node flow balance,capacity and variable value,are taken into consideration.The solution strategy and heuristic algorithm is proposed and verified by the field data from Shanxi province(China).The results show that the model can solve the problem for optimization design of the surface system in complicated CBM fields.

关键词： Coalbed methane Multi-gathering mode Optimization Pipeline network

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采用改进的元胞自动机方法对三元Al-Si-Mg合金凝固微观组织进行数值模拟

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Science China Materials 2024年第4期67卷 1150-1159页

作者：谭云骧赵海东许庆彦 Key Laboratory for Advanced Materials Processing Technology Ministry of EducationSchool of Materials Science and EngineeringTsinghua University Beijing 100084China National Engineering Research Center of Near-Net-Shape for Metalic Materials South China University of TechnologyGuangzhou 510640China

铝硅合金具有轻量化、高强度和易成形等独特优点.这些特性使得在低压压铸下能够生产大型、薄壁、复杂的铸件,这对于车辆轻量化至关重要.然而,这些合金的铸造过程容易产生缺陷,它们的性能与微观结构密切相关.认识到工艺、结构和性能之间... 详细信息

铝硅合金具有轻量化、高强度和易成形等独特优点.这些特性使得在低压压铸下能够生产大型、薄壁、复杂的铸件,这对于车辆轻量化至关重要.然而,这些合金的铸造过程容易产生缺陷,它们的性能与微观结构密切相关.认识到工艺、结构和性能之间的深层联系具有巨大的学术和工程价值.在本工作中,我们通过整合热力学、动力学和多元相图数据库,建立了一个改进的元胞自动机(ICA)模型.基于在阶梯铸件不同位置的冷却曲线和凝固组织,我们建立了适用于Al-7SixMg合金低压铸造的等轴晶形核模型.随后对该合金进行了低压铸造实验,微观结构演变的3D模拟结果与实验观察相吻合.我们进行了阶梯件低压铸造的实验,ICA模型准确地描绘了α-Al树枝晶,以及冷却速率对三元Al-7Si-xMg合金中晶核密度和树枝晶尺寸均匀性的影响.我们的模拟结果与实验数据表现出显著的一致性.此外,我们对SDAS与冷却速率之间的关系进行了全面分析.通过将ICA模型与LGK分析模型进行对比,验证了在评估树枝晶生长速率时ICA模型的精确性.这项工作为集成计算材料工程建立凝固-组织-性能的定量关系提供了理论指导.

关键词：低压铸造冷却曲线凝固微观组织铝硅合金铸造过程尺寸均匀性冷却速率形核模型

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ECG Classification Using Deep CNN Improved by Wavelet Transform

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Computers, Materials & Continua 2020年第9期64卷 1615-1628页

作者： yunxiang zhao Jinyong Cheng Ping Zhang Xueping Peng School of Computer Science and Technology Qilu University of Technology(Shandong Academy of Sciences)Jinan250353China Centre of Artificial Intelligence University of Technology SydneySydneyNSW 2006Australia

Atrial fibrillation is the most common persistent form of arrhythmia.A method based on wavelet transform combined with deep convolutional neural network is applied for automatic classification of electrocardiograms.Since the ECG signal is easily inferred,the ECG signal is decomposed into 9 kinds of subsignals with different frequency scales by wavelet function,and then wavelet reconstruction is carried out after segmented filtering to eliminate the influence of noise.A 24-layer convolution neural network is used to extract the hierarchical features by convolution kernels of different sizes,and finally the softmax classifier is used to classify them.This paper applies this method of the ECG data set provided by the 2017 PhysioNet/CINC challenge.After cross validation,this method can obtain 87.1%accuracy and the F1 score is 86.46%.Compared with the existing classification method,our proposed algorithm has higher accuracy and generalization ability for ECG signal data classification.

关键词： Atrial fibrillation wavelet transform deep CNN

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潮牌联名产品的价格溢出机制

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东华大学学报（自然科学版） 2024年第1期50卷 171-177页

作者：鲁成赵敏何松岳葛云祥东华大学服装与艺术设计学院上海200051 东华大学现代服装设计与技术教育部重点实验室上海200051

针对潮牌联名产品在一、二手市场的价格差异现象,通过理论架构与数据实证分别解析联名产品在一、二手市场中的价格溢出机理。收集8个主品牌、102个副品牌合作的356条潮牌联名产品和交易信息进行实证研究。相关分析与回归分析结果表明:... 详细信息

针对潮牌联名产品在一、二手市场的价格差异现象,通过理论架构与数据实证分别解析联名产品在一、二手市场中的价格溢出机理。收集8个主品牌、102个副品牌合作的356条潮牌联名产品和交易信息进行实证研究。相关分析与回归分析结果表明:一手市场与二手市场溢价影响的机理不同。一手市场价格是由品牌方综合考虑产品成本、消费需求与市场竞争制定的,价格溢出影响因素主要包括副品牌奢侈性、主品牌知名度、品牌类型差异和非联名相似款售价;二手市场价格是消费者对产品价值感知的反映,价格溢出的影响因素主要包括主品牌知名度和非联名相似款售价,而副品牌奢侈性和品牌类型差异的影响不显著。这意味着尽管“傍大款”品牌联名策略能提高产品定价,但并不能显著提高潮牌产品的价值。

关键词：品牌联名溢价潮牌一手市场二手市场

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2-RRR并联机构的运动学及工作空间分析

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组合机床与自动化加工技术 2024年第1期 58-62页

作者：吴昊姜运祥汤赫男赵忆文沈阳工业大学机械工程学院沈阳110870 中国科学院沈阳自动化研究所沈阳110016

针对当前主从式医疗手术机器人主手结构设计及高精度运动的需要,设计了一种可在空间中做定心运动的两自由度并联机构-2RRR型并联机构。首先,基于约束螺旋理论分析了该2-RRR并联机构的自由度数目和性质,并采用修正的Grübler-Kutzbach准... 详细信息

针对当前主从式医疗手术机器人主手结构设计及高精度运动的需要,设计了一种可在空间中做定心运动的两自由度并联机构-2RRR型并联机构。首先,基于约束螺旋理论分析了该2-RRR并联机构的自由度数目和性质,并采用修正的Grübler-Kutzbach准则对机构的自由度分析进行验证;然后,基于机构的结构特性及几何约束条件,采用封闭矢量法构建了机构的正逆运动学模型,获得了其位置的封闭解;最后,通过仿真软件Adams对机构进行了运动学仿真计算验证,仿真结果证明了机构设计的合理性及运动学求解方法的正确性,为该并联机构在医疗手术机器人主手中的设计与应用提供理论依据。

关键词：并联机构自由度运动学工作空间

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覆岩导水裂隙带发育高度动态演化规律研究

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煤矿安全 2024年第2期55卷 176-183页

作者：赵兵朝冯杰赵阳侯恩科马云祥冯欣怡西安科技大学能源学院陕西西安710054 西安科技大学西部矿井开采及灾害防治教育部重点实验室陕西西安710054 西安科技大学地质与环境学院陕西西安710054 国能宁夏煤业集团有限责任公司红柳煤矿宁夏银川751400

为了研究覆岩导水裂隙带发育高度动态演化规律,以小保当矿区2^(-2)煤层为研究对象,通过理论分析、相似模拟实验及实例验证的方法,对导水裂隙带动态发育高度进行研究;借助概率积分法预计其上部岩层移动变形的理论公式,给出了1种基于覆岩... 详细信息

为了研究覆岩导水裂隙带发育高度动态演化规律,以小保当矿区2^(-2)煤层为研究对象,通过理论分析、相似模拟实验及实例验证的方法,对导水裂隙带动态发育高度进行研究;借助概率积分法预计其上部岩层移动变形的理论公式,给出了1种基于覆岩曲率变形的导水裂隙带动态发育高度预计方法。研究表明:导水裂隙带上部岩层下沉系数是1个与挠度及下部自由空间高度相关的分段函数,上部岩层曲率变形大小是决定导水裂隙带发育高度的关键因素;导水裂隙带发育高度与工作面推进长度相关;理论预计小保当矿区2^(-2)煤层导水裂隙带发育高度为160.8 m,相似模拟实验发育高度为155 m,现场实测发育高度为152.01~175.57 m。

关键词：导水裂隙带动态演化下沉系数曲率变形概率积分法

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