forecast

摘要： Severe acute respiratory syndrome coronavirus-2 (SARS CoV-2) has been a global threat spreading in Sierra Leone, and many studies are being conducted using various Statistical models to predict the probable evolution of this pandemic. In this paper, we use the autoregressive integrated moving average (ARIMA) model with the aim of forecasting the cumulative confirmed cases of SARS CoV-2 in Sierra Leone. The Akaike Information Criterion (AIC) was applied to the training data as a criterion method to select the best model. In addition, the statistical measure RMSE and MAPE were utilized for testing this data, and the model with the minimum RMSE and MAPE was selected for future forecasting. ARIMA (3, 2, 1) was confirmed to be the optimal model based on the lowest AIC value. This model was then applied to study the trend of SARS CoV-2 from 1st February 2022 to 30th February 2022. The result shows that incidence of SARS CoV-2 from 1st February 2022 to 30th February 2022, increasing growth steep in Sierra Leone (7718.629, 95% confidence limit of 6785.985 - 8651.274).

摘要： The primary intent of the current research is to provide insights regarding the management of spare parts within the supply chain,in conjunction with offering some methods for enhancing forecasting and inventory management.In particular,to use classical forecasting methods,the use of weak and unstable demand is not recommended.Furthermore,statistical performance measures are not involved in this particular context.Furthermore,it is expected that maintenance contracts will be aligned with different levels.In addition to the examination of some literature reviews,some tools will guide us through this process.The article proposes new performance analysis methods that will help integrate inventory management and statistical performance while considering decision maker priorities through the use of different methodologies and parts age segmentation.The study will also identify critical level policies by comparing different types of spenders according to the inventory management model,also with separate and common inventory policies.Each process of the study is combined with a comparative analysis of different forecasting methods and inventory management models based on N.A.C.C.parts supply chain data,allowing us to identify a set of methodologies and parameter recommendations based on parts segmentation and supply chain prioritization.

摘要： Variability of power generation due to the prevalence of cloud cover over solar photovoltaics(PV)power plants is a challenge faced by grid operators and independent system operators(ISOs)in the integration of solar energy into the grid.Solar forecasts generated through ground⁃based sky imaging systems are useful for short⁃term cloud motion predictions.However,the cost of sky imaging systems currently available in industries is relatively high.Hence,a ground⁃based camera system utilizing a simple webcam is proposed in this study.The proposed method can produce predictions with high levels of accuracy.Forecasts were generated through video analysis using MATLAB for the computation of cloud motion predictions.The image processing involved in the implementation of the proposed system is based on the detection of cloud regions in the form of a cluster of white pixels within individual frames and tracking their motion through comparison of subsequent frames.This study describes the techniques and processes used in the development of the proposed method,along with the evaluation of performance through analysis of the results.The predictions were carried out over multiple time horizons.The time horizons selected include 5,10,15,20,25,and 30 s.The overall results computed showed promising accuracy levels above 94.60%,which makes it adequate for generating reliable forecasts.

摘要： Steel rolling mills have complex processes,specifications,and varieties,along with certain process quality fluctuations and complex production events,making production management decisions difficult.With the development of industrial big data technology,several industrial event solutions based on data have been proposed.These solutions are supported by predictive data and remarkably improve the production level.Taking a heavy plate production line as the research object,through scientific calculations based on historical big data,this paper establishes an optimization logic for plan arrangement,forecasts the quality through the stable relationship between data and quality,intelligently optimizes the subsequent process flow,improves the production line capacity,and reduces the process bottlenecks.

摘要： Adequate power supply is a vital factor in the development of the economic growth of every nation. However, due to changing hydrological conditions, inadequate fuel supplies and dilapidated infrastructure, developing countries face challenges in planning the power grid infrastructure needed to support rapidly growing urban populations. This research seeks to model the monthly electricity power generation for prediction purposes, by implementing stochastic process models on a historical series of monthly electricity power generation in Ghana. A detailed explanation of model selection and forecasting accuracy is presented. The SARIMA (1, 0, 0) × (0, 1, 1)12 model with an AIC score of 439.6995, a BIC score of 446.3537 and an AICc score of 440.8759, has been identified as an appropriate model for predicting monthly electricity power generation in Ghana. The range used was from 2015 to 2019 and it was validated with data from April to December of 2019. The predicted values for 2019 are relatively close to the observed values. Thus, the experimental results show good prediction performances. Therefore, with developed SARIMA model, the forecast is made for the year 2021, proving an increase of monthly power generation. The performance and validation of the SARIMA model were evaluated based on various statistical measures, the test data produced RMSE (55.8606), MAE (45.454) and MAPE (3.0621%). The lagged effect can also help in accurate forecasting and assist policy and decision-makers to establish strategies, priorities on electric power generation.

摘要： The regularities of the dynamics of the average annual temperature of Ber­lin from 1701 to 2021 are revealed.A total of 65 wavelets were received.The temperature has a high quantum certainty,and the change in the aver­age annual temperature of Berlin was identified by a model that contains only two components for prediction.The basis of the forecast at 320 years makes it possible to look into the future until the year 2340.The forecast confirms the conclusions made in the CMIP5 report on global warming.With an increase in the number of components in the model up to five,the forecast is possible only until 2060.Therefore,the model with only two components is workable.The trend is characterized by a modified Man­delbrot equation showing exponential growth with a high growth rate of 1.47421.The wave equation also has an amplitude in the form of the Man­delbrot law(in mathematics,the Laplace law,in biology,the Zipf-Pearl law,in econometrics,the Pareto law),when the exponential growth activity is equal to 1.For 1701,the period of oscillation was 2×60.33333≈120.7 years.By 2021,the period decreased and became equal to 87.6 years.The trend is such that by 2340 the period of oscillation will decrease to 30.2 years.Such an increase in fluctuations indicates an imbalance in climate disturbances in temperature in Berlin.For Berlin,the last three years are characterized by sharp decreases in the average annual temperature from 11.8°C to 10.5°C,i.e.by 12.4% in 2021.Therefore,the forecast is still unstable,as a further decrease in the average annual temperature of Berlin in the near future may change the picture of the forecast.

摘要： As after sales services become more and more popular,particularly preven­tive or corrective maintenance,the intervention and repair of the custom­er’s goods in a timely and efficient manner ensure customer satisfaction and contribute to the establishment of brand image in the market of the suppliers.The availability and quality of spare parts are key elements of this strategy while ensuring minimal management costs.The reuse of spare parts retrieved from customer systems is a growing maintenance strategy practice which impacts the traditional spare parts supply chain.This reuse is primarily driven by extending the economic life of goods,initially re­garded as waste and therefore without added value,by transforming them into valuable spare parts that can be reused;secondly,for environmental or regulatory reasons,demanding responsibility for the treatment of products at the end of their life;and thirdly,to improve the availability of parts for maintenance,especially parts that the organization can no longer purchase or that are impacted by other issues.It also involves the analysis of their condition and their eventual return to working order as they are retrieved from the customer’s systems in a defective condition.In this paper,we will identify and classify the different customers and spare parts by estimating the critical level of rationing policy based on forecasts,identify the thresh­olds of inventory management policies,and finally,compare the different policies by service level and inventory level performance for the N.A.C.C.company.

摘要： The World Bank increased China’s economic growth forecast to 8.5 percent from its initial forecast of 8.1 percent earlier this year owing to stronger-than-expected overseas demand.Factors leading to economic growth include the release of pent-up demand and strong exports.In addition,China achieved a GDP growth of 7.9 percent in Q2,largely spurred by retail sales and industrial production.

摘要： This study examines,diagnoses,and assesses appropriate macroeconomic policy responses of the Montenegrin Government to the outbreak of COVID-19.The model econometrically measures the macroeconomic costs using a Bayesian VARX Litterman/Minessota prior to the pandemic disease in terms of demand and supply loss due to illness and closed activities and their effects on GDP growth in various pandemic scenarios.We explore five economic scenarios—shocks—using the available data from January 2006 to December 2019,following real out-of-sample forecasts generated from January 2020 to December 2020.Sensitivity scenarios spanning January 2020 to June 2020 from±10 to±60%were analyzed.We observed what happens to the supply and demand sides,namely,GDP,tourism,capital stock,human capital,health expenditures,economic freedom,and unemployment.The results show a toll on the GDP,tourism,unemployment,capital stock,and especially human capital for 2020.The recommended policy measures are public finance spending initiatives focused on securing employment and keeping highly qualified staff in Montenegrin companies.Considering all uncertainties,the rebound of the Montenegrin economy could take a few years to reach pre-COVID 19 output levels.

摘要： Offshore wind farm is a key item in green energy and sustainable development. The Taiwan strait owns the world-class wind farm with average wind speed of 12 m/s and a potential for 3000 hours/year of power generation. Compared to wind turbines on land, the offshore wind turbine provide more stable power and less obstacles as well as less power loss. The potential and advantages of offshore wind farm development in the Taiwan strait has become the aims of the Taiwan government policy from now to 2025. This research will collect the historical climate data (wind and wave) of the Taiwan offshore wind farm in the Chan-hwa county. Combined the productivity loss respected to the installation of wind turbine due to different wind speed effect, as well as the productivity loss respected to the construction of pile foundation due to different wave height effect, this study will build up a total project duration forecast system based on the historical climate data of the offshore wind farm. Even the literature views from the experienced projects in North Europe including UK, Netherland and Spain, the climate uncertainty still plays a significant factor of the total construction duration for offshore wind farm. The results of this research can provide a more scientific and reliable duration forecast for future offshore wind farms construction in Taiwan.

摘要： The forecast of highway freight volume is the basis of highway system development and decision-making. In order to improve the accuracy of highway traffic volume forecasting, a gray-Markoy model forforecast is proposed in this paper. This method synthesizes the advantages of GM forecasting method, whichis simple and needs less original data, and of Markov method which possesses the characteristics of randomfluctuation. We can obtain the overall developing trend of freight volume by predicted mean value and maximum status probabihty.

摘要： 本发明属于基础领域，提供了一种基于Forecast函数预测基坑侧壁水平位移的方法及系统。该方法包括，获取基坑侧壁某点的变形值；采用Forecast函数，基于基坑侧壁某点的变形值，得到距离最新测量数据设定天数后的基坑侧壁某点的变形值；根据距离最新测量数据设定天数后的基坑侧壁某点的变形值，结合基坑侧壁安全等级，得到预测变形量。