Prediction of COVID-19 Pandemic Spread in Kingdom of Saudi Arabia

A significant increase in the number of coronavirus cases can easily be noticed in most of the countries around the world. Inspite of the consistent preventive initiatives being taken to contain the spread of this virus, the unabated increase in the cases is both alarming and intriguing. The role of mathematical models in predicting and estimating the spread of the virus, and identifying various preventive factors dependencies has been found important and effective in most of the previous pandemics like Severe Acute Respiratory Syndrome (SARS) 2003. In this research work, authors have proposed the Susceptible-Infectected-Removed (SIR) model variation in order to forecast the pattern of coronavirus disease (COVID-19) spread for the upcoming eight weeks in perspective of Saudi Arabia. The study has been performed by using SIR model with a proposed simplification using average progression for further estimation of β and γ values for better curve fittings ratios. The predictive results of this study clearly show that under the current public health interventions, there will be an increase in the COVID-19 cases in Saudi Arabia in the next four weeks. Hence, a set of strong health primitives and precautionary measures are recommended in order to avoid and prevent the further spread of COVID-19 in Saudi Arabia.     

Prediction Model for Coronavirus Pandemic Using Deep Learning

The recent global outbreak of COVID-19 damaged the world health systems, human health, economy, and daily life badly. None of the countries was ready to face this emerging health challenge. Health professionals were not able to predict its rise and next move, as well as the future curve and impact on lives in case of a similar pandemic situation happened. This created huge chaos globally, for longer and the world is still struggling to come up with any suitable solution. Here the better use of advanced technologies, such as artificial intelligence and deep learning, may aid healthcare practitioners in making reliable COVID-19 diagnoses. The proposed research would provide a prediction model that would use Artificial Intelligence and Deep Learning to improve the diagnostic process by reducing unreliable diagnostic interpretation of chest CT scans and allowing clinicians to accurately discriminate between patients who are sick with COVID-19 or pneumonia, and also empowering health professionals to distinguish chest CT scans of healthy people. The efforts done by the Saudi government for the management and control of COVID-19 are remarkable, however; there is a need to improve the diagnostics process for better perception. We used a data set from Saudi regions to build a prediction model that can help distinguish between COVID-19 cases and regular cases from CT scans. The proposed methodology was compared to current models and found to be more accurate (93 percent) than the existing methods.     

基于改进差分进化和回声状态网络的时间序列预测研究

针对回声状态网络无法根据不同的时间序列有效地选择储备池参数的问题, 本文提出一种新型预测模型, 利用改进的差分进化算法来优化回声状态网络. 其中差分进化算法的缩放因子F、交叉概率CR和变异策略自适应调整, 以提高算法的寻优性能. 为验证本文方法的有效性, 对Lorenz时间序列、大连月平均气温 − 降雨量数据集进行仿真实验. 由实验结果可知, 本文提出的模型可以提高时间序列的预测精度, 且具有良好的泛化能力及实际应用价值.     

A System Approach to Analysis of Adequacy of Nonlinear Time Series Models

A problem of construction of matematical models using time series is considered. The concept of model structure is proposed that is used to develop a model construction technique. Criteria are proposed for determining possible nonlinearities with respect to variables. To estimate adequacy of the model constructed, a set of mutually supplementing statistical criteria is given.     

A Bayesian Multiple Models Combination Method for Time Series Prediction

In this paper we present the Bayesian Combined Predictor (BCP), a probabilistically motivated predictor for time series prediction. BCP utilizes local predictors of several types (e.g., linear predictors, artificial neural network predictors, polynomial predictors etc.) and produces a final prediction which is a weighted combination of the local predictions; the weights can be interpreted as Bayesian posterior probabilities and are computed online. Two examples of the method are given, based on real world data: (a) short term load forecasting for the Greek Public Power Corporation dispatching center of the island of Crete, and (b) prediction of sugar beet yield based on data collected from the Greek Sugar Industry. In both cases, the BCP outperforms conventional predictors.     

An Evolving Autoregressive Predictor for Time Series Forecasting

AR （Autoregressive） model is a common predictor that has been extensively used for time series forecasting. Many training methods can used to update AR model parameters, for instance, least square estimate and maximum likelihood estimate; however, both techniques are sensitive to noisy samples and outliers. To deal with the problems, an evolving AR predictor---EAR, is developed in this work to enhance prediction accuracy and mitigate the effect of noisy samples and outliers. The model parameters of EAR are trained with an ALSE （adaptive least square estimate） method, which can learn samples characteristics more effectively. In each training epoch, the ALSE weights the samples by their fitting accuracy. The samples with larger fitting errors will be given a larger penalty value in the cost function; however, the penalties of difficult-to-predict samples will be adaptively reduced to enhance the prediction accuracy. The effectiveness of the developed EAR predictor is verified by simulation tests. Test results show that the proposed EAR predictor can capture the dynamics of the time series effectively and predict the future trend accurately.     

Time Series Prediction With Genetic-Algorithm Designed Neural Networks: An Empirical Comparison With Modern Statistical Models

Neural networks whose architecture is determined by genetic algorithms outperform autoregressive integrated moving average forecasting models in six different time series examples. Refinements to the autoregressive integrated moving average model improve forecasting performance over standard ordinary least squares estimation by 8% to 13%. In contrast, neural networks achieve dramatic improvements of 10% to 40%. Additionally, neural networks give evidence of detecting patterns in data which remain hidden to the autoregression and moving average models. The consequent forecasting potential of neural networks makes them a very promising addition to the variety of techniques and methodologies used to anticipate future movements in time series.
     

针对通信社会网络的时间序列链接预测算法

已有静态链接预测主要采用覆盖图表示社会网络,利用链接之间的结构信息来预测链接的发生。然而,这些方法仅能预测新链接的发生,而对旧链接的重复发生没有做预测,因此不适合预测重复发生的链接是主要兴趣的应用领域。针对静态链接预测算法的不足,引入时间序列链接预测算法,并且组合静态和时间序列链接预测算法为混合时间序列链接预测算法。在Enron电子邮件数据集上的实验结果表明,时间序列链接预测算法性能优于静态链接预测,混合时间序列链接预测算法的预测性能比单独使用静态或时间序列链接预测算法都要优越。     

Dynamic Ensemble Multivariate Time Series Forecasting Model for PM2.5

In forecasting real time environmental factors, large data is needed to analyse the pattern behind the data values. Air pollution is a major threat towards developing countries and it is proliferating every year. Many methods in time series prediction and deep learning models to estimate the severity of air pollution. Each independent variable contributing towards pollution is necessary to analyse the trend behind the air pollution in that particular locality. This approach selects multivariate time series and coalesce a real time updatable autoregressive model to forecast Particulate matter (PM) PM2.5. To perform experimental analysis the data from the Central Pollution Control Board (CPCB) is used. Prediction is carried out for Chennai with seven locations and estimated PM’s using the weighted ensemble method. Proposed method for air pollution prediction unveiled effective and moored performance in long term prediction. Dynamic budge with high weighted k-models are used simultaneously and devising an ensemble helps to achieve stable forecasting. Computational time of ensemble decreases with parallel processing in each sub model. Weighted ensemble model shows high performance in long term prediction when compared to the traditional time series models like Vector Auto-Regression (VAR), Autoregressive Integrated with Moving Average (ARIMA), Autoregressive Moving Average with Extended terms (ARMEX). Evaluation metrics like Root Mean Square Error (RMSE), Mean Absolute Error (MAE) and the time to achieve the time series are compared.     

Multi-step Learning Rule for Recurrent Neural Models: An Application to Time Series Forecasting

Multi-step prediction is a difficult task that has attracted increasing interest in recent years. It tries to achieve predictions several steps ahead into the future starting from current information. The interest in this work is the development of nonlinear neural models for the purpose of building multi-step time series prediction schemes. In that context, the most popular neural models are based on the traditional feedforward neural networks. However, this kind of model may present some disadvantages when a long-term prediction problem is formulated because they are trained to predict only the next sampling time. In this paper, a neural model based on a partially recurrent neural network is proposed as a better alternative. For the recurrent model, a learning phase with the purpose of long-term prediction is imposed, which allows to obtain better predictions of time series in the future. In order to validate the performance of the recurrent neural model to predict the dynamic behaviour of the series in the future, three different data time series have been used as study cases. An artificial data time series, the logistic map, and two real time series, sunspots and laser data. Models based on feedforward neural networks have also been used and compared against the proposed model. The results suggest than the recurrent model can help in improving the prediction accuracy.     

基于奇异谱分析的机场噪声时间序列预测模型

随着我国民航事业的不断发展,机场噪声问题日益严重。针对机场噪声时间序列预测问题,提出了一种基于奇异谱分析的噪声序列预测模型,即将机场噪声时间序列按照奇异谱分析预测的方法进行奇异值分解,得到主分量和经验正交函数,分析其趋势和振动的特点,然后选择适当的特征向量进行序列重构,通过线性重复公式建立预测模型。在此基础上,提出通过状态转移矩阵确定残差偏离方向,并根据残差的偏离方向和贡献率将重构模型忽略的次要成分计算进去,进而对预测值进行修正。在某机场实测数据中的应用表明,该方法的准确度明显优于已有SSA预测方法。     

基于GM-LSSVR机场噪声时间序列预测模型

随着我国民航事业的不断发展,机场噪声问题日益严重.针对机场噪声时间序列预测问题,在分析了噪声数据特点的基础上,提出了一种基于GM-LSSVR的噪声序列预测模型,即将机场噪声时间序列进行分解,并分别建立趋势项的GM(1,1)模型和剩余项的LSSVR模型,用于机场噪声预测值的计算.在某机场实测数据中的应用表明,该方法的准确度明显优于其他预测方法.     

基于自动编码器的时间序列预测混合模型

时间序列预测目前在众多领域有着广泛应用. 如果可以准确估计事件或指标的未来发展, 它可以帮助人们做出重要的决定. 然而对不同时间序列建立模型并准确预测已成为最具挑战的应用之一. 因此, 本文提出了一种新颖的混合多步预测模型, 称为SSA-ConvBiAE. 首先, 通过奇异谱分析(SSA)将原始数据分解为不同的趋势分量. 其次, 设计了新的基于卷积长短期记忆(ConvLSTM)和双向门控循环单元(BiGRU)的自动编码器网络结构. 最后, 将不同的分量分别输入到对应的自动编码器中进行训练和预测并求和预测结果. 为了评价模型的预测性能, 在真实的供水数据集和公开的时间序列数据集上进行了实验, 实验结果表明, 模型的预测结果优于基线方法. 本文已在网站https://github.com/VIMLab-hfut/SSA-ConvBiAE上发布了源代码.     

Predicting Chaotic Time Series Using Neural and Neurofuzzy Models: A Comparative Study

The prediction accuracy and generalization ability of neural/neurofuzzy models for chaotic time series prediction highly depends on employed network model as well as learning algorithm. In this study, several neural and neurofuzzy models with different learning algorithms are examined for prediction of several benchmark chaotic systems and time series. The prediction performance of locally linear neurofuzzy models with recently developed Locally Linear Model Tree (LoLiMoT) learning algorithm is compared with that of Radial Basis Function (RBF) neural network with Orthogonal Least Squares (OLS) learning algorithm, MultiLayer Perceptron neural network with error back-propagation learning algorithm, and Adaptive Network based Fuzzy Inference System. Particularly, cross validation techniques based on the evaluation of error indices on multiple validation sets is utilized to optimize the number of neurons and to prevent over fitting in the incremental learning algorithms. To make a fair comparison between neural and neurofuzzy models, they are compared at their best structure based on their prediction accuracy, generalization, and computational complexity. The experiments are basically designed to analyze the generalization capability and accuracy of the learning techniques when dealing with limited number of training samples from deterministic chaotic time series, but the effect of noise on the performance of the techniques is also considered. Various chaotic systems and time series including Lorenz system, Mackey-Glass chaotic equation, Henon map, AE geomagnetic activity index, and sunspot numbers are examined as case studies. The obtained results indicate the superior performance of incremental learning algorithms and their respective networks, such as, OLS for RBF network and LoLiMoT for locally linear neurofuzzy model.     

一类非线性系统的基于时间序列的多模型自适应控制

针对一类非线性离散时间系统,提出了一种基于时间序列的多模型自适应控制器(Multiple models adaptive controller, MMAC). 该控制器首先利用聚类方法建立多个线性固定模型,然后,利用系统的时间序列和方向导数建立一个 反映工作点变化趋势的局部加权模型,在此基础上增加了一个全局自适应模型和一个可重新赋值的 自适应模型,并设计了一个切换机构选择最优模型实现控制.仿真结果表明该控制器不但具有良好 的暂态性能、较快的控制速度,而且在相似的控制效果下,可以极大地减少模型的数量.     

Pattern‐Similarity‐Based Model for Time Series Prediction

This research proposes a pattern/shape‐similarity‐based clustering approach for time series prediction. This article uses single hidden Markov model (HMM) for clustering and combines it with soft computing techniques (fuzzy inference system/artificial neural network) for the prediction of time series. Instead of using distance function as an index of similarity, here shape/pattern of the sequence is used as the similarity index for clustering, which overcomes few of the shortcomings associated with distance‐based clustering approaches. Underlying hidden properties of time series are captured with the help of HMM. The prediction method used here exploits the pattern identification prowess of the HMM for cluster selection and the generalization and nonlinear modeling capabilities of soft computing methods to predict the output of the system. To see the validity of the proposed method in the real‐life scenario, it is tested on four different time series. The first is a benchmark Mackey–Glass time series, which is tested for delay parameters τ = 17 and τ = 30. The remaining time series are monthly sunspot data time series, Laser data time series and the last is Lorenz attractor time series. Simulation results show that the proposed method provide a better prediction performance in comparison with the existing methods.     

一种时间序列分解的卫星周期性参数预测方法

卫星遥测参数预测对卫星故障发现有着重要的指导作用。针对周期性参数难以预测的问题,提出了一种基于时间序列分解的卫星周期性参数的预测方法。该方法首先在频域上使用小波分析对参数序列进行降噪并提取参数的周期;然后,在时域上对参数的时间序列进行分解,进一步得到参数的趋势项和随机项,并根据各项特点分别使用灰色模型和ARMA模型进行预测;最后,重组各部分的预测值,得到最终预测结果。通过对我国某卫星遥测数据的对比实验分析,验证了该方法的正确性和有效性。     

针对PM2.5单时间序列数据的动态调整预测模型

针对细颗粒物PM2.5的浓度预测,本文提出了基于单时间序列数据的动态调整模型.在动态指数平滑算法中,指数平滑次数与参数基于样本数据并借助二分查找进行调整.在动态马尔科夫模型中,马尔科夫链的残差状态数、隐马尔科夫模型的隐状态数、连续样本数和阈值参数都通过训练数据加以调整.动态调整模型将指数平滑法和马尔科夫模型有效结合起来,指数平滑法得到的预测值由马尔科夫模型进行校正,从而提高预测准确度.基于大量实际PM2.5数据进行测试,验证了算法的有效性.并与其他现有的灰色模型、人工神经网络、自回归滑动平均模型、支持向量机等方法进行了对比,表明所提模型能够得到精度更高的预测结果.本文模型不局限于PM2.5数据,还可应用于其他类型的数据预测.     

Just-in-Time-Learning based Extended Prediction Self-Adaptive Control for batch processes

This article presents a new Extended Prediction Self-Adaptive Control (EPSAC) algorithm based on the Just-in-Time Learning (JITL) method. In the proposed JITL-based EPSAC design, linearization of the process model is achieved by a set of local state-space models, each of which can be independently and simultaneously identified by the JITL method along the base trajectory. For the end-product quality control for a simulated semi-batch pH-shift reactive crystallization process where shrinking prediction and control horizons are essential, the proposed EPSAC algorithm not only simplifies the control weight tuning but also provides better and more robust closed-loop control performance than its previous counterpart.