期刊文献+
共找到15篇文章
< 1 >
每页显示 20 50 100
Long-Term Electrical Load Forecasting in Rwanda Based on Support Vector Machine Enhanced with Q-SVM Optimization Kernel Function
1
作者 Eustache Uwimana Yatong Zhou Minghui Zhang 《Journal of Power and Energy Engineering》 2023年第8期32-54,共23页
In recent years, Rwanda’s rapid economic development has created the “Rwanda Africa Wonder”, but it has also led to a substantial increase in energy consumption with the ambitious goal of reaching universal access ... In recent years, Rwanda’s rapid economic development has created the “Rwanda Africa Wonder”, but it has also led to a substantial increase in energy consumption with the ambitious goal of reaching universal access by 2024. Meanwhile, on the basis of the rapid and dynamic connection of new households, there is uncertainty about generating, importing, and exporting energy whichever imposes a significant barrier. Long-Term Load Forecasting (LTLF) will be a key to the country’s utility plan to examine the dynamic electrical load demand growth patterns and facilitate long-term planning for better and more accurate power system master plan expansion. However, a Support Vector Machine (SVM) for long-term electric load forecasting is presented in this paper for accurate load mix planning. Considering that an individual forecasting model usually cannot work properly for LTLF, a hybrid Q-SVM will be introduced to improve forecasting accuracy. Finally, effectively assess model performance and efficiency, error metrics, and model benchmark parameters there assessed. The case study demonstrates that the new strategy is quite useful to improve LTLF accuracy. The historical electric load data of Rwanda Energy Group (REG), a national utility company from 1998 to 2020 was used to test the forecast model. The simulation results demonstrate the proposed algorithm enhanced better forecasting accuracy. 展开更多
关键词 SVM Quadratic SVM long-term Electrical Load forecasting Residual Load Demand Series Historical Electric Load
下载PDF
Long-Term Load Forecasting of Southern Governorates of Jordan Distribution Electric System 被引量:1
2
作者 Aouda A. Arfoa 《Energy and Power Engineering》 2015年第5期242-253,共12页
Load forecasting is vitally important for electric industry in the deregulated economy. This paper aims to face the power crisis and to achieve energy security in Jordan. Our participation is localized in the southern... Load forecasting is vitally important for electric industry in the deregulated economy. This paper aims to face the power crisis and to achieve energy security in Jordan. Our participation is localized in the southern parts of Jordan including, Ma’an, Karak and Aqaba. The available statistical data about the load of southern part of Jordan are supplied by electricity Distribution Company. Mathematical and statistical methods attempted to forecast future demand by determining trends of past results and use the trends to extrapolate the curve demand in the future. 展开更多
关键词 long-term LOAD forecasting PEAK LOAD Max DEMAND and Least SQUARES
下载PDF
Long-Term Electricity Demand Forecasting for Malaysia Using Artificial Neural Networks in the Presence of Input and Model Uncertainties
3
作者 Vin Cent Tai Yong Chai Tan +4 位作者 Nor Faiza Abd Rahman Hui Xin Che Chee Ming Chia Lip Huat Saw Mohd Fozi Ali 《Energy Engineering》 EI 2021年第3期715-725,共11页
Electricity demand is also known as load in electric power system.This article presents a Long-Term Load Forecasting(LTLF)approach for Malaysia.An Artificial Neural Network(ANN)of 5-layer Multi-Layered Perceptron(MLP)... Electricity demand is also known as load in electric power system.This article presents a Long-Term Load Forecasting(LTLF)approach for Malaysia.An Artificial Neural Network(ANN)of 5-layer Multi-Layered Perceptron(MLP)structure has been designed and tested for this purpose.Uncertainties of input variables and ANN model were introduced to obtain the prediction for years 2022 to 2030.Pearson correlation was used to examine the input variables for model construction.The analysis indicates that Primary Energy Supply(PES),population,Gross Domestic Product(GDP)and temperature are strongly correlated.The forecast results by the proposed method(henceforth referred to as UQ-SNN)were compared with the results obtained by a conventional Seasonal Auto-Regressive Integrated Moving Average(SARIMA)model.The R^(2)scores for UQ-SNN and SARIMA are 0.9994 and 0.9787,respectively,indicating that UQ-SNN is more accurate in capturing the non-linearity and the underlying relationships between the input and output variables.The proposed method can be easily extended to include other input variables to increase the model complexity and is suitable for LTLF.With the available input data,UQ-SNN predicts Malaysia will consume 207.22 TWh of electricity,with standard deviation(SD)of 6.10 TWh by 2030. 展开更多
关键词 long-term load forecasting SARIMA artificial neural networks uncertainty analysis MALAYSIA
下载PDF
Nonlinear Differential Equation of Macroeconomic Dynamics for Long-Term Forecasting of Economic Development
4
作者 Askar Akaev 《Applied Mathematics》 2018年第5期512-535,共24页
In this article we derive a general differential equation that describes long-term economic growth in terms of cyclical and trend components. Equation is based on the model of non-linear accelerator of induced investm... In this article we derive a general differential equation that describes long-term economic growth in terms of cyclical and trend components. Equation is based on the model of non-linear accelerator of induced investment. A scheme is proposed for obtaining approximate solutions of nonlinear differential equation by splitting solution into the rapidly oscillating business cycles and slowly varying trend using Krylov-Bogoliubov-Mitropolsky averaging. Simplest modes of the economic system are described. Characteristics of the bifurcation point are found and bifurcation phenomenon is interpreted as loss of stability making the economic system available to structural change and accepting innovations. System being in a nonequilibrium state has a dynamics with self-sustained undamped oscillations. The model is verified with economic development of the US during the fifth Kondratieff cycle (1982-2010). Model adequately describes real process of economic growth in both quantitative and qualitative aspects. It is one of major results that the model gives a rough estimation of critical points of system stability loss and falling into a crisis recession. The model is used to forecast the macroeconomic dynamics of the US during the sixth Kondratieff cycle (2018-2050). For this forecast we use fixed production capital functional dependence on a long-term Kondratieff cycle and medium-term Juglar and Kuznets cycles. More accurate estimations of the time of crisis and recession are based on the model of accelerating log-periodic oscillations. The explosive growth of the prices of highly liquid commodities such as gold and oil is taken as real predictors of the global financial crisis. The second wave of crisis is expected to come in June 2011. 展开更多
关键词 long-term Economic Trend Cycles Nonlinear Accelerator Induced and Autonomous Investment Differential Equations of MACROECONOMIC Dynamics Bifurcation Stability CRISIS RECESSION forecasting Explosive Growth in the PRICES of Highly Liquid Commodities as a PREDICTOR of CRISIS
下载PDF
Short-Term and Long-Term Price Forecasting Models for the Future Exchange of Mongolian Natural Sea Buckthorn Market
5
作者 Yalalt Dandar Liu Chang 《Agricultural Sciences》 2022年第3期467-490,共24页
Sea buckthorn market floated uncertainly within a narrow range. The market situation provided upward pressure on prices, and producer and consumer interest were poor, coupled with weak prices in the regional markets. ... Sea buckthorn market floated uncertainly within a narrow range. The market situation provided upward pressure on prices, and producer and consumer interest were poor, coupled with weak prices in the regional markets. The objectives of the study are: 1) to estimate the relationship between wild Sea buckthorn (SB) price and Supply, Demand, while some other factors of crude oil price and exchange rate by using simultaneous Supply-Demand and Price system equation and Vector Error Correction Method (VECM);2) to forecast the short-term and long-term SB price;3) to compare and evaluate the price forecasting models. Firstly, the data was analyzed by Ferris and Engle-Granger’s procedure;secondly, both price forecasting methodologies were tested by Pindyck-Rubinfeld and Makridakis’s procedure. The result shows that the VECM model is more efficient using yearly data;a short-term price forecast decreases, and a long-term price forecast is predicted to increase the Mongolian Sea buckthorn market. 展开更多
关键词 Short-Term and long-term Price forecasting Models Simultaneous System Equation VECM Sea Buckthorn Mongolia
下载PDF
Spatial and temporal synthesized probability gain for middle and long-term earthquake forecast and its preliminary application 被引量:2
6
作者 王晓青 傅征祥 +2 位作者 张立人 粟生平 丁香 《Acta Seismologica Sinica(English Edition)》 CSCD 2000年第1期50-60,共11页
The principle of middle and long-term earthquake forecast model of spatial and temporal synthesized probability gain and the evaluation of forecast efficiency (R-values) of various forecast methods are introduced in t... The principle of middle and long-term earthquake forecast model of spatial and temporal synthesized probability gain and the evaluation of forecast efficiency (R-values) of various forecast methods are introduced in this paper. The R-value method, developed by Xu (1989), is further developed here, and can be applied to more complicated cases. Probability gains in spatial and/or temporal domains and the R-values for different forecast methods are estimated in North China. The synthesized probability gain is then estimated as an example. 展开更多
关键词 probability gain middle and long-term earthquake forecast forecast efficiency evaluation R-value
下载PDF
Study of Holocene glacier degradation in central Asia by isotopic methods for long-term forecast of climate changes
7
作者 Vladimir I. Shatravin Tamara V. Tuzova 《Research in Cold and Arid Regions》 CSCD 2013年第1期114-125,共12页
This article presents a summary of our studies of Holocene moraines and glaciers of the Tien-Shan, Pamir, and Himalaya moun- mills with the purpose of providing pattern regularity of the Holocene glaciation decomposit... This article presents a summary of our studies of Holocene moraines and glaciers of the Tien-Shan, Pamir, and Himalaya moun- mills with the purpose of providing pattern regularity of the Holocene glaciation decomposition. We developed a method for ob- taining reliable radiocarbon dating of moraines with the use of autochthonous organic matter dispersed in fine-grained morainic material, as well there were shown new possibilities of isotope-oxygen and isotope-uranium analysis for the Holocene glaciations dynamics. We found that Holocene glaciations disintegrate stadiaUy according to the decaying principle, and seven main stages may be distinguished. We achieved the absolute dating of the first three stages, identifying these periods as 8,000, 5,000, and 3,400 years ago. The application of the above-mentioned isotope methods of the Holocene glaciations and moraines study will allow re- searchers to improve the offered model of the Holocene glaciations disintegration; it will be great contribution to salvation of the problem of long-term climatic and glaciations forecast. 展开更多
关键词 MORAINES GLACIATION HOLOCENE climate changes long-term forecast central Asia
下载PDF
Identification of expected seismic activity areas by forecasting complex seismic-mode parameters in Uzbekistan
8
作者 T.U.Artikov R.S.Ibragimov +1 位作者 T.L.Ibragimova M.A.Mirzaev 《Geodesy and Geodynamics》 2018年第2期121-130,共10页
In this paper, the author proposed a methodology to reveal expected seismic activation places for coming years by a complex of forecasting parameters of a seismic mode. Areas in Uzbekistan where currently observed ano... In this paper, the author proposed a methodology to reveal expected seismic activation places for coming years by a complex of forecasting parameters of a seismic mode. Areas in Uzbekistan where currently observed anomalies in various parameters of a seismic mode has been revealed. By number of displayed abnormal signs the areas has been ranked based on probability of occurrence of strong earthquakes there. It has prepared schemes of the synoptic forecast of expected seismic activation places in case of occurrence of strong earthquakes in the Central-Asian region. 展开更多
关键词 long-term forecast of earthquakes Parameters of seismic mode Seismic activity Seismic gap
下载PDF
Stock Price Forecasting with Artificial Neural Networks Long Short-Term Memory: A Bibliometric Analysis and Systematic Literature Review
9
作者 Cristiane Orquisa Fantin Eli Hadad 《Journal of Computer and Communications》 2022年第12期29-50,共22页
This study maps the academic literature on Stock Price Forecasting with Long-Term Memory Artificial Neural Networks—RNA LSTM. The objective is to know if it is suitable for time series studies, especially for stock p... This study maps the academic literature on Stock Price Forecasting with Long-Term Memory Artificial Neural Networks—RNA LSTM. The objective is to know if it is suitable for time series studies, especially for stock price projection. Through bibliometric analysis and systematic literature review, it is observed that 333 authors wrote on the topic between 2018 and March 2022, and the journals Expert Systems with Applications, IEEE Access, Big Data Journal and Neural Computing and Applications, published the most relevant articles. Of the 99 articles published in this period, 43 are associated with Chinese institutions, the most cited being that of Kim and Won, who studies the volatility of returns and the market capitalization of South Korean stocks. The basis of 65% of the studies is the comparison between the RNN LSTM and other artificial neural networks. The daily closing price of shares is the most analyzed type of data, and the American (21%) and Chinese (20%) stock exchanges are the most studied. 57% of the studies include improvements to existing neural network models and 42% new projection models. 展开更多
关键词 Stock Price forecasting long-term Memory Backpropagation Bibliometric Analysis Systematic Review
下载PDF
LDformer:a parallel neural network model for long-term power forecasting
10
作者 Ran TIAN Xinmei LI +3 位作者 Zhongyu MA Yanxing LIU Jingxia WANG Chu WANG 《Frontiers of Information Technology & Electronic Engineering》 SCIE EI CSCD 2023年第9期1287-1301,共15页
Accurate long-term power forecasting is important in the decision-making operation of the power grid and power consumption management of customers to ensure the power system’s reliable power supply and the grid econ... Accurate long-term power forecasting is important in the decision-making operation of the power grid and power consumption management of customers to ensure the power system’s reliable power supply and the grid economy’s reliable operation.However,most time-series forecasting models do not perform well in dealing with long-time-series prediction tasks with a large amount of data.To address this challenge,we propose a parallel time-series prediction model called LDformer.First,we combine Informer with long short-term memory(LSTM)to obtain deep representation abilities in the time series.Then,we propose a parallel encoder module to improve the robustness of the model and combine convolutional layers with an attention mechanism to avoid value redundancy in the attention mechanism.Finally,we propose a probabilistic sparse(ProbSparse)self-attention mechanism combined with UniDrop to reduce the computational overhead and mitigate the risk of losing some key connections in the sequence.Experimental results on five datasets show that LDformer outperforms the state-of-the-art methods for most of the cases when handling the different long-time-series prediction tasks. 展开更多
关键词 long-term power forecasting Long short-term memory(LSTM) UniDrop Self-attention mechanism
原文传递
Skill Assessment of Copernicus Climate Change Service Seasonal Ensemble Precipitation Forecasts over Iran
11
作者 Masoud NOBAKHT Bahram SAGHAFIAN Saleh AMINYAVARI 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2021年第3期504-521,共18页
Medium to long-term precipitation forecasting plays a pivotal role in water resource management and development of warning systems.Recently,the Copernicus Climate Change Service(C3S)database has been releasing monthly... Medium to long-term precipitation forecasting plays a pivotal role in water resource management and development of warning systems.Recently,the Copernicus Climate Change Service(C3S)database has been releasing monthly forecasts for lead times of up to three months for public use.This study evaluated the ensemble forecasts of three C3S models over the period 1993-2017 in Iran’s eight classified precipitation clusters for one-to three-month lead times.Probabilistic and non-probabilistic criteria were used for evaluation.Furthermore,the skill of selected models was analyzed in dry and wet periods in different precipitation clusters.The results indicated that the models performed best in western precipitation clusters,while in the northern humid cluster the models had negative skill scores.All models were better at forecasting upper-tercile events in dry seasons and lower-tercile events in wet seasons.Moreover,with increasing lead time,the forecast skill of the models worsened.In terms of forecasting in dry and wet years,the forecasts of the models were generally close to observations,albeit they underestimated several severe dry periods and overestimated a few wet periods.Moreover,the multi-model forecasts generated via multivariate regression of the forecasts of the three models yielded better results compared with those of individual models.In general,the ECMWF and UKMO models were found to be appropriate for one-month-ahead precipitation forecasting in most clusters of Iran.For the clusters considered in Iran and for the long-range system versions considered,the Météo France model had lower skill than the other models. 展开更多
关键词 ensemble forecasts Copernicus Climate Change Service long-term forecasting model evaluation Iran
下载PDF
Long-term Energy Demand and CO_2 Problem in the PRC
12
作者 LQ YingzhongInst. for Techno-Economics and Energy System Analysis. P.O. Box 1021, Beijing 102201, China 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 1991年第1期29-41,共13页
The long-term energy demand in China and the-Chinese share in global CO2 emission are forecasted on the basis of scenarios of population growth and economy development up to 2050 proposed in view of the interaction of... The long-term energy demand in China and the-Chinese share in global CO2 emission are forecasted on the basis of scenarios of population growth and economy development up to 2050 proposed in view of the interaction of energy, economy, environment and social development. The total energy demand in 2050 will reach 4.4~ 5.4 billion tce. It is shown in energy supply analysis that coal is China’s major energy in primary energy supply. The share of CO2 emission in the future Chinese energy system will be out of proportion to its energy consumption share because of the high persentage of coal to be consumed. It will reach about 27%. The nuclear option which would replace 30.7% of coal in the total primary energy supply will reduce the share by 9.8%. So the policy considerations on the future Chinese energy system is of great importance to the global CO2 issues. 展开更多
关键词 long-term forecast Energy demand CO2emission Climate change.
下载PDF
Long-term Prediction and Verification of Rainfall Based on the Seasonal Model
13
作者 Zheng Xiaohua Li Xingmin 《Meteorological and Environmental Research》 CAS 2014年第5期13-14,21,共3页
Using the seasonal cross-multiplication trend model, monthly precipitation of eight national basic weather stations of Shaanxi Province from 2005 to 2010 was predicted, and the forecast results were verified using the... Using the seasonal cross-multiplication trend model, monthly precipitation of eight national basic weather stations of Shaanxi Province from 2005 to 2010 was predicted, and the forecast results were verified using the rainfall scoring rules of China Meteorological Administration. The verification results show that the average score of annual precipitation prediction in recent six years is higher than that made by a professional forecaster, so this model has a good prospect of application. Moreover, the level of making prediction is steady, and it can be widely used in long-term prediction of rainfall. 展开更多
关键词 Seasonal cross-multiplication trend model long-term prediction of rainfall forecast verification China
下载PDF
Long-term system load forecasting based on data-driven linear clustering method 被引量:17
14
作者 Yiyan LI Dong HAN Zheng YAN 《Journal of Modern Power Systems and Clean Energy》 SCIE EI 2018年第2期306-316,共11页
In this paper, a data-driven linear clustering(DLC) method is proposed to solve the long-term system load forecasting problem caused by load fluctuation in some developed cities. A large substation load dataset with a... In this paper, a data-driven linear clustering(DLC) method is proposed to solve the long-term system load forecasting problem caused by load fluctuation in some developed cities. A large substation load dataset with annual interval is utilized and firstly preprocessed by the proposed linear clustering method to prepare for modelling.Then optimal autoregressive integrated moving average(ARIMA) models are constructed for the sum series of each obtained cluster to forecast their respective future load. Finally, the system load forecasting result is obtained by summing up all the ARIMA forecasts. From error analysis and application results, it is both theoretically and practically proved that the proposed DLC method can reduce random forecasting errors while guaranteeing modelling accuracy, so that a more stable and precise system load forecasting result can be obtained. 展开更多
关键词 long-term system load forecasting Datadriven LINEAR clustering AUTOREGRESSIVE integrated moving average(ARIMA) Error analysis
原文传递
China's Macroeconomic Outlook and Risk Assessment: Counterfactual Analysis, Policy Simulation, and Long-Term Governance- A Summary of Annual Report (2015-2016) 被引量:7
15
作者 Kevin X. D. Huang Guoqiang Tian 《Frontiers of Economics in China-Selected Publications from Chinese Universities》 2016年第2期173-191,共19页
Abstract This summary report highlights the confluence of continued downward pressures and deflation scares in the face of looming uncertainty in China's key macroeconomic landscapes. Counterfactual analyses and poli... Abstract This summary report highlights the confluence of continued downward pressures and deflation scares in the face of looming uncertainty in China's key macroeconomic landscapes. Counterfactual analyses and policy simulations are conducted, in addition to benchmark forecasts, based on IAR-CMM model and taking into account both cyclical and secular factors. Economic deceleration is projected to continue in the short to medium term, with real GDP growth declining to 6.3% (5.5% using more reliable instead of official data) in 2016 and facing a significant risk of sliding further down in 2017. Five key factors contributing to the weak outlook, additional to frictions and impediments associated with economic transition/restructuring and lackluster domestic/external demands, are identified, including: lack of new growth/ development engine, exhaustion of government-led driving force, the crowding-out of private sectors by state-owned enterprises (SOEs) with excess capacity/capital overhang, nonperforming government sectors and officials, and twist or misinterpretation of the "New Normal." A root cause of these problems, lying with sluggishness in China's transformation into a market based economy, has to do with overpowered government but underpowered market in resource allocation and government underperformance in enforcing integrity and transparency in the marketplace and in providing public goods and services. At the nexus between inclusive growth and institutional transformation are market oriented and rule of law governed structural reforms and harmonious development. As such, fundamental institutional reforms that dialectically balance demand and supply side factors and properly weigh short run stabilization against long run development should be elevated to the top of the agenda. 展开更多
关键词 macroeconomic forecast risk assessment policy simulation alternative scenarios long-term governance
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部