Combining a neural network and a rule-based expert system for short-term load forecasting

A backpropagation neural network that used the output provided by a rule-based expert system was designed for short-term load forecasting. Extensive studies were performed on the effect of various factors such as learning rate and the number of hidden nodes. Load forecasting was performed on a Taiwan power system to demonstrate that the inclusion of the prediction from a rule-based expert system developed for a power system would improve the predictive capability of the neural network. The hourly power load for two typical days was evaluated, and for both days the inclusion of the rule-based expert system prediction as a network input significantly improved the neural network's prediction of power load. The predictive capability of the network was compared to the expert system as well as to a previously developed neural network. The proposed neural network provided improved predictive capability. In addition, the proposed combined approach converges much faster than both the conventional neural network and the rule-based expert system method.     

蚁群神经网络在短期负荷预测的应用

为了进一步提高BP神经网络的性能,实现准确、快速预测电力系统负荷的目的,将蚁群算法(ACA)作为BP神经网络的学习算法,建立了一种新的蚁群神经网络(AcAN)预测模型.对某电力系统短期负荷预测的计算实例表明,基于蚁群神经网络的负荷预测方法与传统的BP神经网络预测方法相比,具有较强的自适应能力和较好的效果.     

Hybrid partial least squares and neural network approach for short-term electrical load forecasting

Intelligent systems and methods such as the neural network （NN） are usually used in electric power systems for short-term electrical load forecasting. However, a vast amount of electrical load data is often redundant, and linearly or nonlinearly correlated with each other. Highly correlated input data can result in erroneous prediction results given out by an NN model. Besides this, the determination of the topological structure of an NN model has always been a problem for designers. This paper presents a new artificial intelligence hybrid procedure for next day electric load forecasting based on partial least squares （PLS） and NN. PLS is used for the compression of data input space, and helps to determine the structure of the NN model. The hybrid PLS-NN model can be used to predict hourly electric load on weekdays and weekends. The advantage of this methodology is that the hybrid model can provide faster convergence and more precise prediction results in comparison with abductive networks algorithm. Extensive testing on the electrical load data of the Puget power utility in the USA confirms the validity of the proposed approach.     

Hybrid partial least squares and neural network approach for short-term electrical load forecasting

Intelligent systems and methods such as the neural network (NN) are usually used in electric power systems for short-term electrical load forecasting. However, a vast amount of electrical load data is often redundant, and linearly or nonlinearly correlated with each other. Highly correlated input data can result in erroneous prediction results given out by an NN model. Besides this, the determination of the topological structure of an NN model has always been a problem for designers. This paper presents a new artificial intelligence hybrid procedure for next day electric load forecasting based on partial least squares (PLS) and NN. PLS is used for the compression of data input space, and helps to determine the structure of the NN model. The hybrid PLS-NN model can be used to predict hourly electric load on weekdays and weekends. The advantage of this methodology is that the hybrid model can provide faster convergence and more precise prediction results in comparison with abductive networks algorithm. Extensive testing on the electrical load data of the Puget power utility in the USA confirms the validity of the proposed approach.     

改进GA-BPNN在短期电力负荷预测中的应用

为了避免传统方法预测短期电力负荷建模复杂性,将改进遗传算法（GA）和误差反向传播（BP）算法相结合构成的混合算法用于训练人工神经网络,结合电力负荷历史数据,对短期电力负荷进行仿真预测。仿真结果表明,该混合算法有效地解决了常规BP算法学习网络权值收敛速度慢、易陷入局部极小和GA算法独立训练神经网络速度缓慢等问题,具有较快的收敛速度和较高的预测精度。     

基于神经网络的电力负荷预测方法研究

电力负荷预测易受到高频、低频和超低频振荡干扰,导致预测准确性不高,提出基于神经网络的电力负荷预测方法。在无线ZigBee组网协议下进行电力负荷传感器信息组网,构建电网负荷数据采集模型并进行模型修正。根据电力负荷数据采集结果,去除高频、低频和超低频振荡干扰因子。进行神经网络样本数据训练,去除冗余数据,输出电网负荷数据集合。对获得的数据集采用神经网络分类器进行分类融合处理,根据电力负荷数据的融合结果实现电力负荷预测。仿真结果表明,采用该方法进行电力负荷预测的准确性较高,预测过程的抗干扰性较好,在电力负荷的实时监测和信息调度中具有很好的应用价值。     

基于Attention-BiLSTM-LSTM神经网络的短期电力负荷预测方法

短期电力负荷预测是电力系统中的重要问题之一,准确的预测结果可以提高电力市场的灵活性和资源利用效率,对电力系统高效运行具有重要意义.为了提高预测精度,针对电网负荷数据的时序性特征,提出一种基于Attention-BiLSTM-LSTM神经网络的短期电力负荷预测方法.该方法首先针对电力负荷的影响因素(温度、节假日等)提取特...     

基于SGOA神经网络的短期负荷预测

短期负荷预测的结果对电力系统的经济效益具有重要影响。针对多极值问题,首次提出了一种体现大融合思想的共享式全局寻优算法,将几种全局寻优算法有机组合,使它们共享优化信息,协同寻优,从而形成最丰富的寻优机制,达到最强的全局寻优能力。并且为了从根本上提高短期电力负荷预测中神经网络的速度和预测精度,提出了将SGOA算法和BP算法相结合的短期负荷预测方法,用SGOA算法来训练网络参数,直到误差趋于一稳定值,然后用优化的权值进行BP算法。在构建网络模型时,同时也考虑到了气候、温度等因素的影响,对它们进行模糊化处理后作为网络的输入。仿真结果表明基于这一方法的负荷预测系统具有较高的精度和实时性。     

A hierarchical neural model in short-term load forecasting

This paper proposes a novel neural model to the problem of short-term load forecasting (STLF). The neural model is made up of two self-organizing map (SOM) nets—one on top of the other. It has been successfully applied to domains in which the context information given by former events plays a primary role. The model was trained on load data extracted from a Brazilian electric utility, and compared to a multilayer perceptron (MLP) load forecaster. It was required to predict once every hour the electric load during the next 24 h. The paper presents the results, the conclusions, and points out some directions for future work.     

A spiking neural network (SNN) forecast engine for short-term electrical load forecasting

Short-term load forecasting (STLF) is one of the planning strategies adopted in the daily power system operation and control. All though many forecasting models have been developed through the years, the uncertainties present in the load profile significantly degrade the performance of these models. The uncertainties are mainly due to the sensitivity of the load demand with varying weather conditions, consumption pattern during month and day of the year. Therefore, the effect of these weather variables on the load consumption pattern is discussed. Based on the literature survey, artificial neural networks (ANN) models are found to be an alternative to classical statistical methods in terms of accuracy of the forecasted results. However, handling of bulk volumes of historical data and forecasting accuracy is still a major challenge. The development of third generation neural networks such as spike train models which are closer to their biological counterparts is recently emerging as a robust model. So, this paper presents a load forecasting system known as the SNNSTLF (spiking neural network short-term load forecaster). The proposed model has been tested on the database obtained from the Australian Energy Market Operator (AEMO) website for Victoria State.     

电力系统短期负荷预测方法研究综述

根据负荷预测基本流程,分别对数据预处理、模型选取、模型优化分别进行了总结分析。首先对传统的数据处理方法进行了概述,并简要介绍了新的数据处理方法。其次,将现有的短期负荷预测方法分为经典方法、传统方法和智能方法,综合分析了现有预测方法的应用原理,详细分析和比较预测方法的优点和不足之处,为了提高预测的精度,一些新的方法就因运而生,目的在于提高预测精度和适应相应各种运行条件。再次,总结分析了传统的预测优化模型,并简要介绍了现有的一些新的优化模型,这些新的优化模型计算结果相比于传统的模型精确度较高,分析了新优化模型的优点和不足之处。文章最后对了未来电力系统负荷预测提出了展望,在进行短期负荷预测时应该考虑电力市场、新能源、电动汽车相关因素的影响。     

基于多尺度跳跃深度长短期记忆网络的短期多变量负荷预测

近年来,以循环神经网络（RNN）为主体构建的预测模型在短期电力负荷预测中取得了优越的性能。然而,由于RNN不能有效捕捉存在于短期电力负荷数据的多尺度时序特征,因而难以进一步提升负荷预测精度。为了捕获短期电力负荷数据中的多尺度时序特征,提出了一种基于多尺度跳跃深度长短期记忆（MSD-LSTM）网络的短期电力负荷预测模型。具体来说,以长短期记忆（LSTM）网络为主体构建预测模型能够较好地捕获长短期时序依赖,从而缓解时序过长时重要信息容易丢失的问题。进一步地,采用多层LSTM架构并且对各层设置不同的跳跃连接数,使得MSD-LSTM的每一层能够捕获不同时间尺度的特征。最后,引入全连接层把各层提取到的多尺度时序特征进行融合,再利用该融合特征进行短期电力负荷预测。实验结果表明,与单层LSTM和多层LSTM相比,MSD-LSTM的均方误差总体下降了10%。可见MSD-LSTM能够更好地提取短期负荷数据中的多尺度时序特征,从而提高短期电力负荷预测的精度。     

改进的BP算法在短期电力负荷预测中的应用

利用标准BP神经网络建立短期电力负荷预测模型,其算法存在最终解过于依赖初值和过学习现象,并且训练过程中存在局部极小问题且预测精度低等缺点。为了提高电力负荷模型的预测精度,通过阅读相关文献,构建了基于改进BP神经网络的短期电力负荷预测模型,该模型采用遗传算法对权值和阈值进行初始化,以相对误差和附加动量法相结合的方式去计算权值修正量。比较改进后的BP算法和标准BP算法在短期电力负荷预测的效果,从实验仿真的效果表明改进后的模型提高了预测精度。     

Application of a fuzzy neural network combined with a chaos genetic algorithm and simulated annealing to short-term load forecasting

A fuzzy neural network combined with a chaos-search genetic algorithm (CGA) and simulated annealing (SA), hereafter called the FCS method, or simply the FCS, applied to short-term power-system load forecasting as a sample test is proposed in this paper. A fuzzy hyperrectangular composite neural network (FHCNN) is adopted for the initial load forecasting. An integrated CGA and fuzzy system (CGF) and SA is then used to find the optimal FHCNN parameters instead of the ones with the back propagation method. The CGF method will generate a set of parameters for a feasible solution. The CGF method holds good global search capability but poor local search ability. On the contrary, the SA method possesses a good local optimal search capability. We hence propose in this paper to combine the two methods to exploit their advantages and, furthermore, to eliminate the known downside of the traditional artificial neural network. The proposed FCS is next applied to power-system load forecasting as a sample test, which demonstrates an encouraging degree of accuracy superior to other commonly used forecasting methods available. The forecasting results are tabulated and partially converted into bar charts for evaluation and clear comparisons.     

A genetic-algorithm based neural network short-term forecasting framework for database intrusion prediction system

Information systems are one of the most rapidly changing and vulnerable systems, where security is a major issue. The number of security-breaking attempts originated inside the organizations are increasing steadily. Attacks made in this way, usually done by ``authorized' users of the system, cannot be immediately traced. As the idea of filtering the traffic at the entrance door, by using firewalls and the like, is not completely successful, the use of intrusion detection systems should be considered to increase the defense capacity of an information system. This paper presents a framework for a statistical anomaly prediction system using a neuro-genetic forecasting model, which predicts unauthorized invasions of user, based on previous observations and takes further action before intrusion occurs. In this paper, we propose an evolutionary time-series model for short-term database intrusion forecasting using genetic algorithm owing to its global search capability. The experimental results show that the combination strategy(neuro-genetic) can quicken the learning speed of the network and improve the predicting precision compared to the traditional artificial neural network. This paper also focuses on detecting significant changes of transaction intensity for intrusion prediction. The experimental study is performed using real time data provided by a major Corporate Bank. Furthermore, a comparative evaluation of the proposed neuro-genetic model with the traditional feed-forward network trained by the back-propagation with momentum and adaptive learning rate using sum square error on a prediction data set has been presented and a better prediction accuracy has been observed.     

BP neural network with rough set for short term load forecasting

Precise Short term load forecasting (STLF) plays a significant role in the management of power system of countries and regions on the grounds of insufficient electric energy for increased need. This paper presents an approach of back propagation neural network with rough set (RSBP) for complicated STLF with dynamic and non-linear factors to develop the accuracy of predictions. Through attribute reduction based on variable precision with rough set, the influence of noise data and weak interdependency data to BP is avoided so the time taken for training is decreased. Using load time series from a practical power system, we tested the performance of RSBP by comparing its predictions with that of BP network.     

模糊神经网络在非线性短期负荷预测中的应用

为提高负荷预测精度,提出了一种新的4层模糊神经网络短期负荷预测模型.该模型将模糊逻辑和神经网络的长处融合在一起,使模糊推理和解模糊均通过神经网络来实现.选取的隶属函数使神经网络权值有一定的知识表示意义,并通过模糊化层将输入特征量转化为模糊量.在模糊推理层提出了两种不同的算法来完成模糊推理,然后从中确定出模糊取小算法预测效果更好.最后在输出层通过适当的解模糊得到确切的预测输出值.仿真结果表明了该方法的有效性.     

Integrating artificial neural networks with rule-based expert systems

The Rule-Based (RB) and the Artificial Neural Network (ANN) approaches to expert systems development have each demonstrated some specific advantages and disadvantages. These two approaches can be integrated to exploit the advantages and minimize the disadvantages of each method used alone. An RB/ANN integrated approach is proposed to facilitate the development of an expert system which provides a “high-performance” knowledge-based network, an explanation facility, and an input/output facility. In this case study an expert system designed to assist managers in forecasting the performance of stock prices is developed to demonstrate the advantages of this integrated approach and how it can enhance support for managerial decision making.     

A rule-based expert system approach to process selection for cast components

A knowledge-based expert system at the discretion of casting product designers can be employed as a real-time expert advisor to assist product designers to achieve the correct casting design and select the most appropriate casting process for a given component. This paper proposes a rule-based expert system approach for casting process selection, and describes an ongoing rule prototype development. The system in its present development state consists of five interconnected levels each concerning a particular process selection parameter or group of parameters including alloy to be cast, casting geometric features, casting accuracy, production quantity and overall comparative costs. The system progressively evaluates the user's specifications against the capabilities of various casting processes and in each level selects the processes that satisfy the design parameters specified. The final comparative cost level compares the processes that have satisfied all the criteria in the previous levels and recommends the most economical option.     

Federated learning for interpretable short-term residential load forecasting in edge computing network

Neural Computing and Applications - Short-term residential load forecasting is of great significance to smart grid applications. Deep learning techniques, especially recurrent neural networks, can...