541 research outputs found

    Application of Statistical and Artificial Intelligence Techniques for Medium-Term Electrical Energy Forecasting: A Case Study for a Regional Hospital

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    Electrical energy forecasting is crucial for efficient, reliable, and economic operations of hospitals due to serving 365 days a year, 24/7, and they require round-the-clock energy. An accurate prediction of energy consumption is particularly required for energy management, maintenance scheduling, and future renewable investment planning of large facilities. The main objective of this study is to forecast electrical energy demand by performing and comparing well-known techniques, which are frequently applied to short-term electrical energy forecasting problem in the literature, such as multiple linear regression as a statistical technique and artificial intelligence techniques including artificial neural networks containing multilayer perceptron neural networks and radial basis function networks, and support vector machines through a case study of a regional hospital in the medium-term horizon. In this study, a state-of-the-art literature review of medium-term electrical energy forecasting, data set information, fundamentals of statistical and artificial intelligence techniques, analyses for aforementioned methodologies, and the obtained results are described meticulously. Consequently, support vector machines model with a Gaussian kernel has the best validation performance, and the study revealed that seasonality has a dominant influence on forecasting performance. Hence heating, ventilation, and air-conditioning systems cover the major part of electrical energy consumption of the regional hospital. Besides historical electrical energy consumption, outdoor mean temperature and calendar variables play a significant role in achieving accurate results. Furthermore, the study also unveiled that the number of patients is steady over the years with only small deviations and have no significant influence on medium-term electrical energy forecasting

    The use of computational intelligence techniques for mid-term electricity price forecasting

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    Dissertation presented as the partial requirement for obtaining a Master's degree in Information Management, specialization in Information Systems and Technologies ManagementWe currently live in a world ruled by large amounts of data. Organizations’ success is highly determined by the way they foresee and assess changes occurring in the future. Predictive data analytics is the art of building and using models that create forecasts based on patterns extracted from historical data. So, it is a process of making projections about a specific event which the outcome is still unknown in the present. One of the main applications is price prediction (Kelleher, Namee, & D’Arcy, 2015). Price prediction can be applied in innumerous types of business, including the energy sector. Additionally, Big Data has created opportunities for development of new energy services and bears a promise of better energy management and conservation (Grolinger, L’Heureux, Capretz, & Seewald, 2016). Whenever prediction deals with time-series data, it can be designated as forecasting. The electricity spot prices (ESP) represent the result of the market bidding prices outcome, in the electric wholesale market. Predicting these prices is an important and impactful task for market participants, like producers, consumers and retailers, since the principal objective for such players is to achieve the lowest cost in comparison with competitors. ESP play a huge role in energy market’s decision making. It is important both for developing proper bidding strategies as well as for making conscient and sustainable investment decisions (Keynia & Heydari, 2019). Additionally, it impacts the decision of the technologies to use, for example, choosing between renewable energy generators or classic gas turbines. Furthermore, the topic of electricity prices forecasting is extremely relevant for both developed and developing countries. Developed countries search for their economic prospect’s improvement. Electric energy efficiency is a crucial metric for that improvement. Electric energy efficiency can decrease the electricity prices thanks to the reduction of consumption, thus decreasing the need of having new expensive power generation and diminishing the pressure on energy resources. Therefore, ESP behavior is an important factor in their economy. Regarding developing economies, which have faced problems to take the populations out of poverty, the electricity sector restructuring has been fundamental for helping increase the levels of economic development (Ebrahimian, Barmayoon, Mohammadi, & Ghadimi, 2018)

    ANN application in maritime industry : Baltic Dry Index forecasting & optimization of the number of container cranes

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    This dissertation is a study of dry bulk freight index forecasting and port planning, both based on Artificial Neural network application. First the dry bulk market is reviewed, and the reason for the high fluctuation of freight rates through the demand-supply mechanism is examined. Due to the volatile BDI, the traditional linear regression forecasting method cannot guarantee the performance of forecasting, but ANN overcomes this difficulty and gives better performance especially in a short time. Besides, in order to improve the performance of ANN further, wavelet is introduced to pre-process the BDI data. But when the noise (high frequency parts) is stripped, the hidden useful data may also be eliminated. So the performance of different degrees of de-noising models is evaluated, and the best one (most suitable de-noising model) is chosen to forecast BDI, which avoids over de-noising and keeps a fair ability of forecasting. In the second case study, the collected container terminals and ranked, and the throughput of each combination (different crane number) is estimated by applying a trained BP network. The BP network with DEA output is combined, simulating the efficiency of each combination. And finally, the optimal container crane number is fixed due to the highest efficiency and practical reasons. The Conclusion and Recommendation chapter gives some further advice, and many recommendations are given

    Machine Learning methods for long and short term energy demand forecasting

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    The thesis addresses the problems of long- and short- term electric load demand forecasting by using a mixed approach consisting of statistics and machine learning algorithms. The modelling of the multi-seasonal component of the Italian electric load is investigated by spectral analysis combined with machine learning. In particular, a frequency-domain version of the LASSO is developed in order to enforce sparsity in the parameter and efficiently obtain the main harmonics of the multi-seasonal term. The corresponding model yields one-year ahead forecasts whose Mean Absolute Percentage Error (MAPE) has the same order of magnitude of the one-day ahead predictor currently used by the Italian Transmission System Operator. Again for the Italian case, two whole-day ahead predictors are designed. The former applies to normal days while the latter is specifically designed for the Easter week. Concerning normal days, a predictor is built that relies exclusively on the loads recorded in the previous days, without resorting to exogenous data such as weather forecasts. This approach is viable in view of the highly correlated nature of the demand series, provided that suitable regularization-based strategies are applied in order to reduce the degrees of freedom and hence the parameters variance. The obtained forecasts improve significantly on the Terna benchmark predictor. The Easter week predictor is based on a Gaussian process model, whose kernel, differently from standard choices, is statistically designed from historical data. Again, even without using temperatures, a definite improvement is achieved over the Terna predictions. In the last chapter of the thesis, aggregation and enhancement techniques are introduced in order to suitably combine the prediction of different experts. The results, obtained on German national load data, show that, even in the case of missing experts, the proposed strategies yield to more accurate and robust predictions.The thesis addresses the problems of long- and short- term electric load demand forecasting by using a mixed approach consisting of statistics and machine learning algorithms. The modelling of the multi-seasonal component of the Italian electric load is investigated by spectral analysis combined with machine learning. In particular, a frequency-domain version of the LASSO is developed in order to enforce sparsity in the parameter and efficiently obtain the main harmonics of the multi-seasonal term. The corresponding model yields one-year ahead forecasts whose Mean Absolute Percentage Error (MAPE) has the same order of magnitude of the one-day ahead predictor currently used by the Italian Transmission System Operator. Again for the Italian case, two whole-day ahead predictors are designed. The former applies to normal days while the latter is specifically designed for the Easter week. Concerning normal days, a predictor is built that relies exclusively on the loads recorded in the previous days, without resorting to exogenous data such as weather forecasts. This approach is viable in view of the highly correlated nature of the demand series, provided that suitable regularization-based strategies are applied in order to reduce the degrees of freedom and hence the parameters variance. The obtained forecasts improve significantly on the Terna benchmark predictor. The Easter week predictor is based on a Gaussian process model, whose kernel, differently from standard choices, is statistically designed from historical data. Again, even without using temperatures, a definite improvement is achieved over the Terna predictions. In the last chapter of the thesis, aggregation and enhancement techniques are introduced in order to suitably combine the prediction of different experts. The results, obtained on German national load data, show that, even in the case of missing experts, the proposed strategies yield to more accurate and robust predictions

    Modeling Long- and Short-Term Temporal Patterns with Deep Neural Networks

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    Multivariate time series forecasting is an important machine learning problem across many domains, including predictions of solar plant energy output, electricity consumption, and traffic jam situation. Temporal data arise in these real-world applications often involves a mixture of long-term and short-term patterns, for which traditional approaches such as Autoregressive models and Gaussian Process may fail. In this paper, we proposed a novel deep learning framework, namely Long- and Short-term Time-series network (LSTNet), to address this open challenge. LSTNet uses the Convolution Neural Network (CNN) and the Recurrent Neural Network (RNN) to extract short-term local dependency patterns among variables and to discover long-term patterns for time series trends. Furthermore, we leverage traditional autoregressive model to tackle the scale insensitive problem of the neural network model. In our evaluation on real-world data with complex mixtures of repetitive patterns, LSTNet achieved significant performance improvements over that of several state-of-the-art baseline methods. All the data and experiment codes are available online.Comment: Accepted by SIGIR 201

    Forecasting Automobile Demand Via Artificial Neural Networks & Neuro-Fuzzy Systems

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    The objective of this research is to obtain an accurate forecasting model for the demand for automobiles in Iran\u27s domestic market. The model is constructed using production data for vehicles manufactured from 2006 to 2016, by Iranian car makers. The increasing demand for transportation and automobiles in Iran necessitated an accurate forecasting model for car manufacturing companies in Iran so that future demand is met. Demand is deduced as a function of the historical data. The monthly gold, rubber, and iron ore prices along with the monthly commodity metals price index and the Stock index of Iran are Artificial neural network (ANN) and artificial neuro-fuzzy system (ANFIS) have been utilized in many fields such as energy consumption and load forecasting fields. The performances of the methodologies are investigated towards obtaining the most accurate forecasting model in terms of the forecast Mean Absolute Percentage Error (MAPE). It was concluded that the feedforward multi-layer perceptron network with back-propagation and the Levenberg-Marquardt learning algorithm provides forecasts with the lowest MAPE (5.85%) among the other models. Further development of the ANN network based on more data is recommended to enhance the model and obtain more accurate networks and subsequently improved forecasts

    Novel Computationally Intelligent Machine Learning Algorithms for Data Mining and Knowledge Discovery

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    This thesis addresses three major issues in data mining regarding feature subset selection in large dimensionality domains, plausible reconstruction of incomplete data in cross-sectional applications, and forecasting univariate time series. For the automated selection of an optimal subset of features in real time, we present an improved hybrid algorithm: SAGA. SAGA combines the ability to avoid being trapped in local minima of Simulated Annealing with the very high convergence rate of the crossover operator of Genetic Algorithms, the strong local search ability of greedy algorithms and the high computational efficiency of generalized regression neural networks (GRNN). For imputing missing values and forecasting univariate time series, we propose a homogeneous neural network ensemble. The proposed ensemble consists of a committee of Generalized Regression Neural Networks (GRNNs) trained on different subsets of features generated by SAGA and the predictions of base classifiers are combined by a fusion rule. This approach makes it possible to discover all important interrelations between the values of the target variable and the input features. The proposed ensemble scheme has two innovative features which make it stand out amongst ensemble learning algorithms: (1) the ensemble makeup is optimized automatically by SAGA; and (2) GRNN is used for both base classifiers and the top level combiner classifier. Because of GRNN, the proposed ensemble is a dynamic weighting scheme. This is in contrast to the existing ensemble approaches which belong to the simple voting and static weighting strategy. The basic idea of the dynamic weighting procedure is to give a higher reliability weight to those scenarios that are similar to the new ones. The simulation results demonstrate the validity of the proposed ensemble model
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