This study proposes an anomaly detection method for the friction stir welding process using a variational autoencoder, which is a representative deep generative model in machine learning, with two time-series data: te...
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ISBN:
(纸本)9780791887882
This study proposes an anomaly detection method for the friction stir welding process using a variational autoencoder, which is a representative deep generative model in machine learning, with two time-series data: temperature near a tool probe tip and a tool shoulder tip and bending force on a tool. We mention a square butt welding process of a pair of aluminum alloy plates. Through preliminary welding experiments, normal and anomalous data are collected to construct a VAE network used for anomaly detection in square butt joining. The effectiveness of the proposed method is demonstrated through validation experiments by comparing the proposed VAE method with an autoencoder.
variational autoencoder (VAE) is considered as an emerging model for ensuring competitive performance in recommender systems. However, its performance is severely limited by the amount of training examples and, as a r...
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ISBN:
(纸本)9781665408981
variational autoencoder (VAE) is considered as an emerging model for ensuring competitive performance in recommender systems. However, its performance is severely limited by the amount of training examples and, as a result, existing VAE models may fail to provide satisfactory recommendation results in presence of highly sparse user-item interactions. In this paper, we propose a self-supervised VAE model, SSVAE in short, to improve the generalization ability of VAE model on the sparse interaction datasets. Concretely, we first build multiple views for each user by data augmentation, and then design a pretext task to align the representations learned from different views of each user. Particularly, SSVAE aims to optimize a combined objective of recommendation task and pretext task, making them to reinforce each other during the learning process. Our encouraging experimental results on three real-world benchmarks validate the superiority of our SSVAE model to state-of-the-art VAE style recommendation techniques.
We investigate the effect of variational autoencoder (VAE) based data anonymization and its ability to preserve anomalous subgroup properties. We present a Utility Guaranteed Deep Privacy (UGDP) system which casts exi...
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ISBN:
(纸本)9781509066315
We investigate the effect of variational autoencoder (VAE) based data anonymization and its ability to preserve anomalous subgroup properties. We present a Utility Guaranteed Deep Privacy (UGDP) system which casts existing anomalous pattern detection methods as a new utility measure for data synthesis. UGDP's approach shows that properties of an anomalous subset of records, identified in the original data set, are preserved through the anonymization of a VAE. This is despite the newly generated records being completely synthetic. More specifically, the Bias-Scan algorithm identifies a subgroup of records that are consistently over- (or under-) risked by a black-box classifier as an area of 'poor fit'. This scanning process is applied on both pre- and post- VAE synthesized data. The areas of poor fit (i.e. anomalous records) persist in both settings. We evaluate our approach using publicly available datasets from the financial industry. Our evaluation confirmed that the approach is able to produce synthetic datasets that preserved a high level of subgroup differentiation as identified initially in the original dataset. Such a distinction was maintained while having distinctly different records between the synthetic and original dataset.
In this paper, we propose Squeezed Convolutional variational autoencoder (SCVAE) for anomaly detection in time series data for Edge Computing in Industrial Internet of Things (IIoT). The proposed model is applied to l...
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ISBN:
(纸本)9781538653845
In this paper, we propose Squeezed Convolutional variational autoencoder (SCVAE) for anomaly detection in time series data for Edge Computing in Industrial Internet of Things (IIoT). The proposed model is applied to labeled time series data from UCI datasets for exact performance evaluation, and applied to real world data for indirect model performance comparison. In addition, by comparing the models before and after applying Fire Modules from SqueezeNet, we show that model size and inference times are reduced while similar levels of performance is maintained.
Grasp planning and most specifically the grasp space exploration is still an open issue in robotics. This article presents an efficient procedure for exploring the grasp space of a multifingered adaptive gripper for g...
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ISBN:
(纸本)9781728190778
Grasp planning and most specifically the grasp space exploration is still an open issue in robotics. This article presents an efficient procedure for exploring the grasp space of a multifingered adaptive gripper for generating reliable grasps given a known object pose. This procedure relies on a limited dataset of manually specified expert grasps, and use a mixed analytic and data-driven approach based on the use of a grasp quality metric and variational autoencoders. The performances of this method are assessed by generating grasps in simulation for three different objects. On this grasp planning task, this method reaches a grasp success rate of 99.91% on 7000 trials.
Aiming at learning a probabilistic distribution over data, generative models have been actively studied with broad applications. This paper proposes a complex recurrent variational autoencoder (VAE) framework, for mod...
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ISBN:
(纸本)9798350359329;9798350359312
Aiming at learning a probabilistic distribution over data, generative models have been actively studied with broad applications. This paper proposes a complex recurrent variational autoencoder (VAE) framework, for modeling time series data, particularly speech signals. First, to account for the temporal structure of speech signals, we introduce complex-valued recurrent neural network in the framework. Then, inspired by recent advancements in speech enhancement and separation, the reconstruction loss in the proposed model is L1-based loss, considering penalty on both complex and magnitude spectrograms. To exemplify the use of the complex generative model, we choose speech resynthesis first and then enhancement as the specific application in this paper. Experiments are conducted on the VCTK, TIMIT, and VoiceBank+DEMAND datasets. The results show that the proposed method can resynthesize complex spectrogram well, and offers improvements on objective metrics in speech intelligibility and signal quality for enhancement.
Knowledge tracking (KT) is a task that predicting the degree of students' knowledge mastery through their learning interaction records. Although existing works improve predictive capability with well-designed neur...
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ISBN:
(纸本)9789819772438;9789819772445
Knowledge tracking (KT) is a task that predicting the degree of students' knowledge mastery through their learning interaction records. Although existing works improve predictive capability with well-designed neural network models or hypothetical learning mechanisms, the predictive performance is compromised in the scenarios of quantity limited interaction data. In this paper, we utilize variational autoencoder (VAE) and pre-trained network to generate question answer sequence data pairs related to the original interaction data, which can improve the performance of the model when added to the training set even in the case of data scarcity. Specifically, the steps of the data augmentation method for KT we proposed are as follows: 1) Question sequence generation. Generate latent question sequences that are similar to the real interaction question sequences from the pre-designed VAE model. 2) Answer sequence generation. Put the generated data into the pre-trained KT model to get reliable answer label sequences that correspond to latent question sequences. 3) Samples generation and training. Combine the two types of generated sequences as new samples for KT task training. We apply the data augmentation method on four classic datasets and demonstrate its effectiveness by reaching the state-of-the-art performance with an average AUC index improvement of 2.41%. We also verify the method on artificially random extracted data, and with only 20% of the data, it even achieves similar results compared with other methods using 100% of the data.
Self-localization is a crucial task for robots, demanding high accuracy. In this work, we propose a new robot localization method based on the variational autoencoder (VAE). In our method, the robot utilizes the captu...
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ISBN:
(纸本)9798350307627
Self-localization is a crucial task for robots, demanding high accuracy. In this work, we propose a new robot localization method based on the variational autoencoder (VAE). In our method, the robot utilizes the captured image to generate robot localization in indoor environments. The utilization of VAE makes the system adaptive to varying environmental conditions. Our findings demonstrate that utilizing both the robot's coordinates and images as training data significantly enhances the accuracy of robot self-localization estimation and improves the robustness of the system due to sensor data noise.
Anomaly detection in hyperspectral images is an important and challenging problem. Most available data sets are unlabeled, and very few are labelled. In this paper, we proposed a lightweight variational autoencoder an...
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ISBN:
(纸本)9789819916474;9789819916481
Anomaly detection in hyperspectral images is an important and challenging problem. Most available data sets are unlabeled, and very few are labelled. In this paper, we proposed a lightweight variational autoencoder anomaly detector (VAE-AD) for hyperspectral data. VAE is used to learn the background distribution of the image, and thereafter it is used to construct a background representation for each pixel. Further reconstruction error is calculated between the background reconstructed image and the original image used for anomaly detection. A GMM-based post-processing step is used to construct the final detection map. The comparative analysis with five real-world hyperspectral data sets shows that the proposed model achieves better or comparable results with few learning parameters of the model, and with less time.
Learning precise representations of users and items to fit observed interaction data is the fundamental task of collaborative filtering. Existing studies usually infer entangled representations to fit such interaction...
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ISBN:
(纸本)9781611978032
Learning precise representations of users and items to fit observed interaction data is the fundamental task of collaborative filtering. Existing studies usually infer entangled representations to fit such interaction data, neglecting to model the diverse matching relationships between users and items behind their interactions, leading to limited performance and weak interpretability. To address this problem, we propose a Dual Disentangled variational autoencoder (DualVAE) for collaborative recommendation, which combines disentangled representation learning with variational inference to facilitate the generation of implicit interaction data. Specifically, we first implement the disentangling concept by unifying an attention-aware dual disentanglement and disentangled variational autoencoder to infer the disentangled latent representations of users and items. Further, to encourage the correspondence and independence of disentangled representations of users and items, we design a neighborhood-enhanced representation constraint with a customized contrastive mechanism to improve the representation quality. Extensive experiments on three real-world benchmarks show that our proposed model significantly outperforms several recent state-of-the-art baselines. Further empirical experimental results also illustrate the interpretability of the disentangled representations learned by DualVAE.
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