采用编码输入的生成对抗网络故障检测方法及应用

针对传统基于生成对抗网络的故障检测方法中，生成器输入使用随机噪声，不包含训练集中有效信息造成模型检测效果不够理想的问题，提出一种采用编码输入的生成对抗网络故障检测策略。通过引入自编码器，基于最小化重构误差构建隐变量空间，将降维后的隐变量信息作为生成器输入以提升生成对抗网络的训练效果；进一步考虑故障检测方法中基于生成器的统计量计算成本高和对离群点敏感的问题，计算待测样本经编码后的隐变量到训练集隐变量空间中心点的曼哈顿距离，并作为新统计量进行故障检测。将所提故障检测方法用于田纳西伊斯曼过程及实际的磨煤机过程，本文方法较传统生成对抗网络故障检测在田纳西伊斯曼过程上报警率提升了13%，在磨煤机过程上各统计量报警率均得到了显著提升且本文所提统计量将传统方法中针对生成器的统计量大大降低了检测用时，从而验证了方法的有效性和性能。     

ST-Trader:A Spatial-Temporal Deep Neural Network for Modeling Stock Market Movement

Stocks that are fundamentally connected with each other tend to move together.Considering such common trends is believed to benefit stock movement forecasting tasks.However,such signals are not trivial to model because the connections among stocks are not physically presented and need to be estimated from volatile data.Motivated by this observation,we propose a framework that incorporates the inter-connection of firms to forecast stock prices.To effectively utilize a large set of fundamental features,we further design a novel pipeline.First,we use variational autoencoder(VAE)to reduce the dimension of stock fundamental information and then cluster stocks into a graph structure(fundamentally clustering).Second,a hybrid model of graph convolutional network and long-short term memory network(GCN-LSTM)with an adjacency graph matrix(learnt from VAE)is proposed for graph-structured stock market forecasting.Experiments on minute-level U.S.stock market data demonstrate that our model effectively captures both spatial and temporal signals and achieves superior improvement over baseline methods.The proposed model is promising for other applications in which there is a possible but hidden spatial dependency to improve time-series prediction.     

Software Defect Prediction Based on Non-Linear Manifold Learning and Hybrid Deep Learning Techniques

Software defect prediction plays a very important role in software quality assurance, which aims to inspect as many potentially defect-prone software modules as possible. However, the performance of the prediction model is susceptible to high dimensionality of the dataset that contains irrelevant and redundant features. In addition, software metrics for software defect prediction are almost entirely traditional features compared to the deep semantic feature representation from deep learning techniques. To address these two issues, we propose the following two solutions in this paper: (1) We leverage a novel non-linear manifold learning method - SOINN Landmark Isomap (SLIsomap) to extract the representative features by selecting automatically the reasonable number and position of landmarks, which can reveal the complex intrinsic structure hidden behind the defect data. (2) We propose a novel defect prediction model named DLDD based on hybrid deep learning techniques, which leverages denoising autoencoder to learn true input features that are not contaminated by noise, and utilizes deep neural network to learn the abstract deep semantic features. We combine the squared error loss function of denoising autoencoder with the cross entropy loss function of deep neural network to achieve the best prediction performance by adjusting a hyperparameter. We compare the SL-Isomap with seven state-of-the-art feature extraction methods and compare the DLDD model with six baseline models across 20 open source software projects. The experimental results verify that the superiority of SL-Isomap and DLDD on four evaluation indicators.     

复合调制AM广播接收机的DL-SAE码元判决法

调幅波段数字广播系统采用AM-MPPSK(amplitude modulation—m-ary phase position shift keying)复合调制有众多优势。针对AM-MPPSK复合调制系统的数字解调部分,提出了基于DL-SAE(deep learning-sparse autoencoder)的码元判决法。利用深度学习中的稀疏自编码网络从接收信号样本中抽取出包含码间干扰在内的信号特征后,利用深度学习对稀疏自编码网络进行训练,使其能够在较强码间干扰环境下对接收信号样本进行分类,从而实现对于AM-MPPSK复合调制系统的抗码间干扰的解调。提出的码元判决法可将解调误码率从传统匹配滤波判决和幅度判决算法的10-2量级降低到10-4量级,比传统的判决法有着更为优异的解调性能和更强的适应能力。     

基于栈式自动编码的图像哈希算法

随着网络图像的快速发展,在大型图像检索系统中哈希算法成为近似最近邻查询算法的研究重点。本文提出一种基于深度模型的哈希算法—深度哈希。通过深度卷积神经网络提取的图像高维全局特征,用栈式自动编码器对特征进行无监督学习得到二进制哈希编码,利用图像标签语义相似性对栈式自动编码器的参数进行微调,最后用汉明距离来计算图像的相似性。本文提出的深度哈希在图像检索中取得了较好的结果。     

Online learning-based predictive control of crystallization processes under batch-to-batch parametric drift

This work considers a seeded fesoterodine fumarate (FF) cooling crystallization and presents the methodology and implementation of a real-time machine learning modeling-based predictive controller to handle batch-to-batch (B2B) parametric drift. Specifically, an autoencoder recurrent neural network-based model predictive controller (AERNN-MPC) is developed to optimize product yield, crystal size, and energy consumption while accounting for the physical constraints on cooling jacket temperature. Deviations in the kinetic parameters are considered in the closed-loop simulations to account for the B2B parametric drift, and two error-triggered online update mechanisms are proposed to address issues pertaining to the availability of real-time crystal property measurements and are incorporated into the AERNN-MPC to improve the model prediction accuracy. Closed-loop simulation results demonstrate that the proposed AERNN-MPC with online update, irrespective of the accessibility to real-time crystal property data, achieves a desired closed-loop performance in terms of maximizing product yield and minimizing energy consumption.     

Remaining useful life prediction of bearing based on stacked autoencoder and recurrent neural network

Remaining Useful Life (RUL) prediction play a crucial part in bearing maintenance, which directly affects the production efficiency and safety of equipment. Moreover, the accuracy of the prediction model is constrained by the feature extraction process and full life data of bearings. In this paper, the life prediction method of faulty rolling bearing with limited data is presented including degradation state model and RUL prediction model. In order to obtain health indication (HI) without human interference in the degradation state modeling stage, the bottleneck structure of Stacked Autoencoder (SAE) is utilized to fuse the four selected features into one HI using Intelligent Maintenance Systems (IMS) bearing dataset as training sample. In RUL prediction model, the Long Short-Term Memory (LSTM) neural network is carried out to establish the model with Standard deviation (Std) input and HI training label. In order to solve the problem of large training error caused by insufficient data in the failure stage of bearing acceleration test, the third-order spline curve interpolation is utilized to enhance the data points. Through parameter analysis, the RMSE and MAE of the test set on the prediction model are 0.032582 and 0.024038, respectively. Furthermore, the effectiveness of the proposed method is further validated by dataset from Case Western Reserve University (CWRU) with different bearing fault degrees. The analysis indicates that the RUL prediction of bearing fault data is consistent with the size of artificial added faults, that is,the more severe the fault the shorter the time of remaining life. The results validate that the proposed method can effectively extract the bearing health state by incorporating feature fusion and establish accurately prediction model for bearing remaining life.     

面向异质变分超图自动编码器的超边链接预测模型

如何采用超边建模网络数据中的多元关联关系,实现潜在超边链接关系的预测具有重要的现实意义。现有方法主要集中于研究具有成对关系的网络数据,然而,直接将现有的链接预测方法用于超图网络中的超边链接预测具有一定的局限性。因此,提出基于异质变分超图自动编码器的超边链接预测模型(heterogeneous variational hypergraph autoencoder,HVGAE)。首先,利用超图卷积实现变分超图自动编码器,将超图网络数据转换成一种低维空间表示;其次,加入节点近邻度函数,最大程度地保留其结构信息,从而构建异质超图网络超边链接预测模型。针对三种不同类型的超图网络进行实验,结果表明相比其他的基准方法,HVGAE模型获得了较好的预测结果,说明其能够较好地解决超图网络中的超边链接预测问题。     

融合注意力机制的深度混合推荐算法

大量研究利用用户或项目的边信息来缓解视频推荐中的数据稀疏和冷启动问题,取得了一定的效果,但是没有关注辅助信息中的关键信息.针对此问题进行了研究,提出了一种融合双注意力机制的深度混合推荐模型.该模型通过融合自注意力机制的卷积神经网络挖掘项目端隐藏因子,同时融合自注意力机制的堆栈去噪自编码器提取用户端隐藏因子,深度挖掘项目端和用户端的重要信息.最后,通过结合概率矩阵分解实现视频评分预测.在两个公开数据集上的大量实验结果表明,提出的方法结果在已有ConvMF+、PHD、DUPIA等基线模型基础上有一定提升.     

对抗学习遥感图像场景识别

目的 在高分辨率遥感图像场景识别问题中,经典的监督机器学习算法大多需要充足的标记样本训练模型,而获取遥感图像的标注费时费力。为解决遥感图像场景识别中标记样本缺乏且不同数据集无法共享标记样本问题,提出一种结合对抗学习与变分自动编码机的迁移学习网络。方法 利用变分自动编码机（variational auto-encoders,VAE）在源域数据集上进行训练,分别获得编码器和分类器网络参数,并用源域编码器网络参数初始化目标域编码器。采用对抗学习的思想,引入判别网络,交替训练并更新目标域编码器与判别网络参数,使目标域与源域编码器提取的特征尽量相似,从而实现遥感图像源域到目标域的特征迁移。结果 利用两个遥感场景识别数据集进行实验,验证特征迁移算法的有效性,同时尝试利用SUN397自然场景数据集与遥感场景间的迁移识别,采用相关性对齐以及均衡分布适应两种迁移学习方法作为对比。两组遥感场景数据集间的实验中,相比于仅利用源域样本训练的网络,经过迁移学习后的网络场景识别精度提升约10%,利用少量目标域标记样本后提升更为明显;与对照实验结果相比,利用少量目标域标记样本时提出方法的识别精度提升均在3%之上,仅利用源域标记样本时提出方法场景识别精度提升了10%~40%;利用自然场景数据集时,方法仍能在一定程度上提升场景识别精度。结论 本文提出的对抗迁移学习网络可以在目标域样本缺乏的条件下,充分利用其他数据集中的样本信息,实现不同场景图像数据集间的特征迁移及场景识别,有效提升遥感图像的场景识别精度。