Long short-term memory

长期短期记忆
  • 文章类型: Journal Article
    准确的水质预测有助于水资源的智能化管理。水质指标具有时间序列特征和非线性,但是现有模型在引入长短期记忆(LSTM)时只关注前向时间序列,没有考虑模型上的并行计算。正因为如此,构建了一个名为LSTM-多头注意力(LMA)的新神经网络来预测水质,利用长短期记忆对时序数据进行处理,利用多头注意进行并行计算和特征信息提取。此外,水质指数存在数据类型多、数据关联复杂的问题,以及水质数据中的数据缺失和数据异常问题。为了解决这些问题,这项研究提出了一种称为GRA-LMA的基于线性插值的水质预测模型,灰色关联分析和LMA。以淮河流域水质数据为案例,进行了两个实验,验证了GRA-LMA的预测性能。第一个实验侧重于数据处理,包括水质数据的缺失数据和异常数据的处理,水质指标的相关性分析。线性插值适用于处理丢失的数据,同时采用箱线图和直方图相结合的方法对异常数据进行分析和剔除,然后用线性插值修复异常数据。采用灰色关联分析法计算不同水质指标之间的关联度,和相关性较高的水质指标,以确定水质预测模型的输入变量。数据处理结果表明,使用灰色关联分析可以在不改变数据变化模式和模型的情况下使用线性插值进行修复,以减少其输入所需的数据量。在第二个实验中,GRA-LMA和反向传播神经网络(BP)等现有模型的预测能力,递归神经网络(RNN),长短期记忆(LSTM),和门循环单元(GRU)使用不同的数值和图形性能评估指标进行评估和比较。对比实验结果表明,pH值均方误差,溶解氧,化学需氧量,氨氮,电导率,浊度,总磷,GRA-LMA的总氮减少到0.05890、0.40196、0.322454、0.04368、14.71003、8.13252、0.01558和0.14345。结果表明,GRA-LMA对各种水质指标具有较好的预测适应性,并能显著降低预测误差。
    Accurate prediction of water quality contributes to the intelligent management of water resources. Water quality indices have time series characteristics and nonlinearity, but the existing models only focus on the forward time series when long short-term memory (LSTM) is introduced and do not consider the parallel computation on the model. Owing to this, a new neural network called LSTM-multihead attention (LMA) was constructed to predict water quality, using long short-term memory to process time series data and multihead attention for parallel computing and extracting feature information. Additionally, water quality indices have the issues of multiple data types and complex data correlations, as well as missing data and abnormal data problems in water quality data. In order to solve these problems, this study proposes a water quality prediction model called GRA-LMA-based linear interpolation, gray relational analysis and LMA. Two experiments are carried out to verify the predictive performance of the GRA-LMA with the water quality data of the Huaihe River Basin as a case study sample. The first experiment focuses on data processing, including the processing of missing data and abnormal data of water quality data, and the correlation analysis of water quality indices. Linear interpolation is adapted to process the missing data, while a combination of boxplot and histogram is adopted to analyze and eliminate the abnormal data, which is then repaired the abnormal data with linear interpolation. The gray relational analysis is adopted to calculate the correlation between different water quality indices, and water quality indices with high correlation are retained to determine the input variables of the water quality prediction model. The data processing results demonstrate that repairs can be made using linear interpolation without altering the pattern of data change and the model by using the gray relational analysis to reduce the quantity of data it needs as input. In the second experiment, the predictive capacity of GRA-LMA and existing models such as backpropagation neural network (BP), recurrent neural network (RNN), long short-term memory (LSTM), and gate recurrent unit (GRU) was evaluated and compared using different numerical and graphical performance evaluation metrics. Comparative experimental results show that the mean square error of pH, dissolved oxygen, chemical oxygen demand, ammonia nitrogen, electrical conductivity, turbidity, total phosphorus, and total nitrogen of GRA-LMA is reduced to 0.05890, 0.40196, 0.32454, 0.04368, 14.71003, 8.13252, 0.01558, and 0.14345. The results indicate that GRA-LMA has superior adaptability for predicting various water quality indices and can significantly lower the induced prediction error.
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  • 文章类型: Journal Article
    目的:深度学习(DL)是一种在各个领域开发人工智能的最新技术,它提高了自然语言处理(NLP)的性能。因此,我们旨在开发一种基于DL的NLP模型,该模型可对放射学报告中的骨转移(BM)状态进行分类,以检测BM患者.
    方法:基于DL的NLP模型是通过使用以日语编写的1,749份自由文本放射学报告训练长期短期记忆而开发的。我们采用了五折交叉验证,并使用了200份报告来测试这五个模型。准确性,灵敏度,特异性,精度,和受试者工作特征曲线下面积(AUROC)用于模型评估。
    结果:所开发的模型显示出分类性能,其平均值±标准偏差为0.912±0.012、0.924±0.029、0.901±0.014、0.898±0.012和0.968±0.004,灵敏度,特异性,精度,AUROC,分别。
    结论:提出的基于DL的NLP模型可能有助于早期有效地检测BM患者。
    OBJECTIVE: Deep learning (DL) is a state-of-the-art technique for developing artificial intelligence in various domains and it improves the performance of natural language processing (NLP). Therefore, we aimed to develop a DL-based NLP model that classifies the status of bone metastasis (BM) in radiology reports to detect patients with BM.
    METHODS: The DL-based NLP model was developed by training long short-term memory using 1,749 free-text radiology reports written in Japanese. We adopted five-fold cross-validation and used 200 reports for testing the five models. The accuracy, sensitivity, specificity, precision, and area under the receiver operating characteristics curve (AUROC) were used for the model evaluation.
    RESULTS: The developed model demonstrated classification performance with mean ± standard deviation of 0.912 ± 0.012, 0.924 ± 0.029, 0.901 ± 0.014, 0.898 ± 0.012, and 0.968 ± 0.004 for accuracy, sensitivity, specificity, precision, and AUROC, respectively.
    CONCLUSIONS: The proposed DL-based NLP model may help in the early and efficient detection of patients with BM.
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  • 文章类型: Journal Article
    使用能够预测光伏(PV)能源生产的模型对于确保该能源与传统配电网的最佳集成至关重要。长短期记忆网络(LSTM)通常用于此目的,但它们的使用可能不是更好的选择,因为它们的计算复杂性很大,推理和训练时间较慢。因此,在这项工作中,我们寻求评估神经网络MLP(多层感知器)的使用,循环神经网络(RNN),和LSTMs,用于预测5min的光伏能源产量。预测的每次迭代都使用从光伏系统收集的最后120分钟的数据(功率,辐照,和PV电池温度),从2019年到2022年年中在Maceió(巴西)测量。此外,使用贝叶斯超参数优化来获得每个模型的最佳结果,并在平等的基础上进行比较。结果表明,MLP表现令人满意,需要更少的时间来训练和预测,表明在特定情况下处理非常短期的预测时,它们可能是一个更好的选择,例如,在计算资源很少的系统中。
    The use of models capable of forecasting the production of photovoltaic (PV) energy is essential to guarantee the best possible integration of this energy source into traditional distribution grids. Long Short-Term Memory networks (LSTMs) are commonly used for this purpose, but their use may not be the better option due to their great computational complexity and slower inference and training time. Thus, in this work, we seek to evaluate the use of neural networks MLPs (Multilayer Perceptron), Recurrent Neural Networks (RNNs), and LSTMs, for the forecast of 5 min of photovoltaic energy production. Each iteration of the predictions uses the last 120 min of data collected from the PV system (power, irradiation, and PV cell temperature), measured from 2019 to mid-2022 in Maceió (Brazil). In addition, Bayesian hyperparameters optimization was used to obtain the best of each model and compare them on an equal footing. Results showed that the MLP performs satisfactorily, requiring much less time to train and forecast, indicating that they can be a better option when dealing with a very short-term forecast in specific contexts, for example, in systems with little computational resources.
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  • 文章类型: Journal Article
    碳交易价格(CTP)预测的准确性对市场参与者和政策制定者都至关重要。就目前情况而言,以前的大多数研究只关注一个或几个碳交易市场,暗示模型的普遍性不足以进行验证。通过对中国所有碳交易市场的案例研究,本研究提出了点和区间的混合CTP预测模型。首先,采用Pearson相关方法识别CTP的关键影响因素。然后使用具有自适应噪声的完全集合经验模式分解将原始CTP数据分解为多个序列。在此之后,采用样本熵方法对序列进行重构,减少计算时间,避免过度分解。在此之后,建立了用Adam算法优化的长短期记忆法来实现CTP的点预测。最后,核密度估计方法用于预测CTP间隔。一方面,结果证明了该模型的有效性和优越性。区间预测模型,另一方面,反映了市场参与者行为的不确定性,这在碳交易市场的运作中更为实际。
    Carbon trading price (CTP) prediction accuracy is critical for both market participants and policymakers. As things stand, most previous studies have only focused on one or a few carbon trading markets, implying that the models\' universality is insufficient to be validated. By employing a case study of all carbon trading markets in China, this study proposes a hybrid point and interval CTP forecasting model. First, the Pearson correlation method is used to identify the key influencing factors of CTP. The original CTP data is then decomposed into multiple series using complete ensemble empirical mode decomposition with adaptive noise. Following that, the sample entropy method is used to reconstruct the series to reduce computational time and avoid overdecomposition. Following that, a long short-term memory method optimized by the Adam algorithm is established to achieve the point forecasting of CTP. Finally, the kernel density estimation method is used to predict CTP intervals. On the one hand, the results demonstrate the proposed model\'s validity and superiority. The interval prediction model, on the other hand, reflects the uncertainty of market participants\' behavior, which is more practical in the operation of carbon trading markets.
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  • 文章类型: Journal Article
    实时预测河流本身的状况及其对人民的受益程度是实现人水和谐的主导方式。采用指标评分法作为评价方法,我们使用具有时间序列特征的河流评估数据和结果作为特征和标签,并将迁移学习的概念应用于长短期记忆,建立了六个子系统,包括水安全,水质,经济贡献,水生态,水管理和水文化,对我国淮河流域江苏段河流幸福度进行实时滚动评价仿真研究。实证结果表明,各系统的训练集和测试集的最大均方根误差(RMSE)为0.0226,最低判定系数R2为0.9011,证明模型拟合良好,根据该数据,引入了2022年6月分水岭的相关数据,评价结果为89.77分。总体趋势是好的,但是可以发现经济贡献水平有一定的回落趋势,客观地分析了原因。
    Real-time prediction of the state of the river itself and the degree of its benefit to the people is the leading way to achieve human-water harmony. Using the indicator scoring method as the evaluation method, we used the river evaluation data and results with time series characteristics as features and labels and applied the concept of transfer learning to Long Short-Term Memory to establish six subsystems, including water safety, water quality, economic contribution, water ecology, water management and water culture, to conduct a real-time rolling evaluation simulation study on the degree of river happiness in the Jiangsu section of the Huaihe River Basin in China. The empirical results show that the maximum Root Mean Square Error (RMSE) of the training set and test set of each system is 0.0226, and the lowest coefficient of determination R2 is 0.9011, which proves that the model fits well, according to which the relevant data of the watershed in June 2022 are brought in, and the evaluation result is obtained as 89.77 points. The overall trend is good, but a certain tendency to fall back at the level of economic contribution can be found, and the reasons are analyzed objectively.
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  • 文章类型: Journal Article
    当前高级驾驶辅助系统(ADAS)的设计主要开发统一的碰撞预警算法,忽略了驾驶行为的异质性,因此导致司机对低信任。为了解决这个问题,开发个性化驾驶辅助算法是一种有前途的方法。然而,当前的个性化系统主要通过手动调整警告触发阈值来实现,这对整体司机来说不太可行,因为需要某些领域的专业知识来准确地设置个人门槛。其他个性化技术利用个人驱动程序数据来构建个性化模型。这种方法可以学习个人行为,但需要不切实际的大规模个人数据收集。为了填补空白,提出了基于联邦学习的个性化前向碰撞预警(FCW)自适应算法。通过FCW的长期短期记忆(LSTM)建立了基线模型。然后引入了联合学习框架,以从具有隐私保护的多个驾驶员那里收集知识。具体来说,通过从各个车辆服务器模型收集更新的参数而不是收集原始数据来训练通用云服务器模型。此外,在每个车辆服务器模型中添加了特定于驾驶员的批量标准化(BN)层,以解决驾驶行为的异质性。实验表明,所提出的具有BN层的基于联邦的个性化模型具有最佳性能。平均建模精度达到84.88%,性能与常规总数据采集训练方法相当,其中额外的BN层可以提高3.48%的精度。最后,讨论了拟议框架的应用及其进一步的研究。
    Current designs of advanced driving assistance systems (ADAS) mainly developed uniform collision warning algorithms, which ignore the heterogeneity of driving behaviors, thus lead to low drivers\' trust in. To address this issue, developing personalized driving assistance algorithms is a promising approach. However, current personalization systems were mainly implemented through manually adjusting warning trigger thresholds, which would be less feasible for overall drivers as certain domain expertise is required to set personal thresholds accurately. Other personalization techniques exploited individual drivers\' data to build personalized models. Such approach could learn personal behavior but requires impractical large-scale individual data collections. To fill up the gaps, self-adaptive algorithms for personalized forward collision warning (FCW) based on federated learning were proposed in this study. A baseline model was developed by long short-term memory (LSTM) for FCW. Federated learning framework was then introduced to collect knowledge from multiple drivers with privacy preserving. Specifically, a general cloud server model was trained by collecting updated parameters from individual vehicle server models rather than collecting raw data. Besides, a driver-specific batch normalization (BN) layer was added into each vehicle server model to address the heterogeneity of driving behaviors. Experiments show empirically that the proposed federated-based personalized models with the BN layer showed to have the best performance. The average modeling accuracy has reached 84.88% and the performance is comparable to conventional total data collection training approach, where the additional BN layer could increase the accuracy by 3.48%. Finally, applications of the proposed framework and its further investigations have been discussed.
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  • 文章类型: Journal Article
    这项研究是使用具有先进机动性的无人机进行的,以开发统一的传感器和通信系统作为原位大气测量的新平台。作为空气污染的主要原因,颗粒物(PM)已引起全球关注。我们开发了一个小的,轻量级,简单,和具有成本效益的多传感器系统,用于大气现象和相关环境信息的多种测量。对于现场局部区域测量,我们使用了具有实时监控和可视化软件应用程序的远程无线通信模块。此外,我们开发了四个原型支架,具有传感器的最佳分配,设备,和安装在无人机上的摄像头作为统一的系统平台。校准实验结果,与两个高级PM2.5传感器的数据相比,证明了我们的传感器系统遵循整体趋势和变化。在三个周围环境不同的地点进行飞行测量实验后,我们获得了原始数据集。实验获得的预测结果与使用相应数据集训练的长短期记忆(LSTM)网络获得的区域PM2.5趋势相匹配。
    This study was conducted using a drone with advanced mobility to develop a unified sensor and communication system as a new platform for in situ atmospheric measurements. As a major cause of air pollution, particulate matter (PM) has been attracting attention globally. We developed a small, lightweight, simple, and cost-effective multi-sensor system for multiple measurements of atmospheric phenomena and related environmental information. For in situ local area measurements, we used a long-range wireless communication module with real-time monitoring and visualizing software applications. Moreover, we developed four prototype brackets with optimal assignment of sensors, devices, and a camera for mounting on a drone as a unified system platform. Results of calibration experiments, when compared to data from two upper-grade PM2.5 sensors, demonstrated that our sensor system followed the overall tendencies and changes. We obtained original datasets after conducting flight measurement experiments at three sites with differing surrounding environments. The experimentally obtained prediction results matched regional PM2.5 trends obtained using long short-term memory (LSTM) networks trained using the respective datasets.
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  • 文章类型: Journal Article
    Basal/acetazolamide brain perfusion single-photon emission computed tomography (SPECT) has been used to evaluate functional hemodynamics in patients with carotid artery stenosis. We aimed to develop a deep learning model as a support system for interpreting brain perfusion SPECT leveraging unstructured text reports.
    In total, 7345 basal/acetazolamide brain perfusion SPECT images and their text reports were retrospectively collected. A long short-term memory (LSTM) network was trained using 500 randomly selected text reports to predict manually labeled structured information, including abnormalities of basal perfusion and vascular reserve for each vascular territory. Using this trained LSTM model, we extracted structured information from the remaining 6845 text reports to develop a deep learning model for interpreting SPECT images. The model was based on a 3D convolutional neural network (CNN), and the performance was tested on the other 500 cases by measuring the area under the receiver-operating characteristic curve (AUC). We then applied the model to patients who underwent revascularization (n = 33) to compare the estimated output of the CNN model for pre- and post-revascularization SPECT and clinical outcomes.
    The AUC of the LSTM model for extracting structured labels was 1.00 for basal perfusion and 0.99 for vascular reserve for all 9 brain regions. The AUC of the CNN model designed to identify abnormal perfusion was 0.83 for basal perfusion and 0.89 for vascular reserve. The output of the CNN model was significantly improved according to the revascularization in the target vascular territory, and its changes in brain territories were concordant with clinical outcomes.
    We developed a deep learning model to support the interpretation of brain perfusion SPECT by converting unstructured text reports into structured labels. This model can be used as a support system not only to identify perfusion abnormalities but also to provide quantitative scores of abnormalities, particularly for patients who require revascularization.
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