scholarly journals Hybrid model of ARIMA-linear trend model for tourist arrivals prediction model in Surakarta City, Indonesia

2019 ◽  
Author(s):  
Purwanto ◽  
Sunardi ◽  
Fenty Tristanti Julfia ◽  
Aditya Paramananda
2014 ◽  
Vol 5 (1) ◽  
pp. 327-362 ◽  
Author(s):  
L. Østvand ◽  
K. Rypdal ◽  
M. Rypdal

Abstract. Various interpretations of the notion of a trend in the context of global warming are discussed, contrasting the difference between viewing a trend as the deterministic response to an external forcing and viewing it as a slow variation which can be separated from the background spectral continuum of long-range persistent climate noise. The emphasis in this paper is on the latter notion, and a general scheme is presented for testing a multi-parameter trend model against a null hypothesis which models the observed climate record as an autocorrelated noise. The scheme is employed to the instrumental global sea-surface temperature record and the global land temperature record. A trend model comprising a linear plus an oscillatory trend with period of approximately 70 yr, and the statistical significance of the trends, are tested against three different null models: first-order autoregressive process, fractional Gaussian noise, and fractional Brownian motion. The parameters of the null models are estimated from the instrumental record, but are also checked to be consistent with a Northern Hemisphere temperature reconstruction prior to 1750 for which an anthropogenic trend is negligible. The linear trend in the period 1850–2010 AD is significant in all cases, but the oscillatory trend is insignificant for ocean data and barely significant for land data. However, by using the significance of the linear trend to constrain the null hypothesis, the oscillatory trend in the land record appears to be statistically significant. The results suggest that the global land record may be better suited for detection of the global warming signal than the ocean record.


2021 ◽  
Vol 11 ◽  
Author(s):  
Runping Hou ◽  
Xiaoyang Li ◽  
Junfeng Xiong ◽  
Tianle Shen ◽  
Wen Yu ◽  
...  

BackgroundFor stage IV patients harboring EGFR mutations, there is a differential response to the first-line TKI treatment. We constructed three-dimensional convolutional neural networks (CNN) with deep transfer learning to stratify patients into subgroups with different response and progression risks.Materials and MethodsFrom 2013 to 2017, 339 patients with EGFR mutation receiving first-line TKI treatment were included. Progression-free survival (PFS) time and progression patterns were confirmed by routine follow-up and restaging examinations. Patients were divided into two subgroups according to the median PFS (<=9 months, > 9 months). We developed a PFS prediction model and a progression pattern classification model using transfer learning from a pre-trained EGFR mutation classification 3D CNN. Clinical features were fused with the 3D CNN to build the final hybrid prediction model. The performance was quantified using area under receiver operating characteristic curve (AUC), and model performance was compared by AUCs with Delong test.ResultsThe PFS prediction CNN showed an AUC of 0.744 (95% CI, 0.645–0.843) in the independent validation set and the hybrid model of CNNs and clinical features showed an AUC of 0.771 (95% CI, 0.676–0.866), which are significantly better than clinical features-based model (AUC, 0.624, P<0.01). The progression pattern prediction model showed an AUC of 0.762(95% CI, 0.643–0.882) and the hybrid model with clinical features showed an AUC of 0.794 (95% CI, 0.681–0.908), which can provide compensate information for clinical features-based model (AUC, 0.710; 95% CI, 0.582–0.839).ConclusionThe CNN exhibits potential ability to stratify progression status in patients with EGFR mutation treated with first-line TKI, which might help make clinical decisions.


Author(s):  
Dahir Abdi Ali ◽  
Muhammad Sani

Somalia has recorded the first confirmed Covid-19 case and first death case on March 16, and April 08, 2020, respectively. Since its arrival, it had infected 2,603 people and took the lives of 88 people while 577 patients were recovered as of 14 June, 2020. To fight this pandemic, the government requires to make the necessary plans accordingly. To plan effectively, the government needs to answer this question: what will be the effect of Covid-19 cases in the country? To answer this question accurately and objectively, forecasting the spread of confirmed Covid-19 cases will be vital. To this regard, this paper provides real times forecasts of Covid-19 cases employing Holt's linear trend model without seasonality. Provided that the data employed is accurate and the past pattern of the disease will continue in the future, this model is powerful to produce real time forecasts in the future with some degree of uncertainty. With the help of these forecasts, the government can make evidence based decisions by utilizing the scarce resource available at its disposal.


Information ◽  
2018 ◽  
Vol 9 (7) ◽  
pp. 177 ◽  
Author(s):  
Guohui Li ◽  
Xiao Ma ◽  
Hong Yang

The matter of success in forecasting precipitation is of great significance to flood control and drought relief, and water resources planning and management. For the nonlinear problem in forecasting precipitation time series, a hybrid prediction model based on variational mode decomposition (VMD) coupled with extreme learning machine (ELM) is proposed to reduce the difficulty in modeling monthly precipitation forecasting and improve the prediction accuracy. The monthly precipitation data in the past 60 years from Yan’an City and Huashan Mountain, Shaanxi Province, are used as cases to test this new hybrid model. First, the nonstationary monthly precipitation time series are decomposed into several relatively stable intrinsic mode functions (IMFs) by using VMD. Then, an ELM prediction model is established for each IMF. Next, the predicted values of these components are accumulated to obtain the final prediction results. Finally, three predictive indicators are adopted to measure the prediction accuracy of the proposed hybrid model, back propagation (BP) neural network, Elman neural network (Elman), ELM, and EMD-ELM models: mean absolute error (MAE), root mean squared error (RMSE), and mean absolute percentage error (MAPE). The experimental simulation results show that the proposed hybrid model has higher prediction accuracy and can be used to predict the monthly precipitation time series.


2014 ◽  
Vol 635-637 ◽  
pp. 662-665
Author(s):  
Zhen Lin Chen ◽  
Fang Zhao ◽  
Xiao Zhang

For realizing the dynamic optimization of measuring instrument calibration interval, predicting the history calibration data by modeling. First the improved moving average method is used to modeling and to predict the development trend of parameters. On the basis of this, BP network is used to compensate the predicted residual sequence, so as to get more accurate forecasts. Then improved MA - BP prediction model is given to optimize the calibration interval dynamically. The model is verified through experiments. The results show that the model has higher prediction precision and better universality.


1980 ◽  
Vol 8 (6) ◽  
pp. 928-941 ◽  
Author(s):  
Kathryn E. Newcomer ◽  
Richard J. Hardy

1997 ◽  
Vol 13 (3) ◽  
pp. 463-463 ◽  
Author(s):  
Badi H. Baltagi ◽  
Walter Krämer

2010 ◽  
Vol 108-111 ◽  
pp. 893-897 ◽  
Author(s):  
Hong Qiong Huang ◽  
Shu Lan Lin ◽  
Tian Hao Tang ◽  
Ji Fang Li

Based on the idea of the neural network, intelligent computing methods are used to analyze temporal and spatial data. We present the temporal and spatial autocorrelation moving average (STARMA) model based on the in-depth systematic study on time sequence of hybrid model. Firstly this paper uses radial basis function neural network to extract the temporal and spatial sequence which is non-stationary caused by large-scale non-linear trend, secondly this paper presents STARMA modeling of small-scale random spatial and temporal variation. Comparative analysis between the original data and the forecasting data shows that proposed hybrid model has better performance of fitting and generalization.


2021 ◽  
Vol 26 (2) ◽  
pp. 64-71
Author(s):  
Md Hossain

The aim of this paper was to explore the appropriate deterministic time series model using the latest selection criteria considering the price pattern of onion, garlic and potato products in Bangladesh (January 2000 to December 2016). It appeared from our analysis that the time series data for the prices of potato was first order homogenous stationary but onion and garlic were found to be the second order stationary. Four different forecasting models namely, linear trend model, quadratic trend model, exponential growth model, and S-curve trend model were used to find the best fitted model for the prices of above mentioned products in the Bangladesh. Three accuracy measures such as mean absolute percentage error (MAPE), mean absolute deviation (MAD) and mean squared deviation (MSD) were used for the selection of the best fitted model based on lowest value of forecasting error. Lowest values of these errors indicated a best fitted model. After choosing the best growth model by the latest model selection criteria, prices of selected agricultural commodities were forecasted using the following time-series analysis methods: Simple Exponential Method, Double Exponential Method using the time period from January 2017 to December 2021. The findings of this study would be useful for policy makers, researchers, businessmen as well as producers in order to forecast future prices of these commodities.


Author(s):  
Anna Bagirova ◽  
Oksana Shubat

Russian demographic statistics does not provide information about the number of grandparents. The aim of our study is to present models for forecasting their number. We used data from the Human Fertility Database to estimate the average age of a mother at the birth of her first child. Based on the simulated age of Russian women’s entry into grandparenthood, the time series of the number of Russian grandmothers was created. To obtain prospective estimates of the number of Russian grandmothers, we tested various models used in demography to forecast population size – mathematical (based on exponential and logistic functions) and statistical (based on statistical characteristics of time series). To estimate the number of grandmothers who are significantly involved in caring for grandchildren, we used data from the Federal statistical survey. Our results are as follows: 1) there is an increase in the age of entry into grandparenthood; 2) we estimated the size of potential grandmothers in different years and we found two models which are more appropriate for forecasting: linear trend model and average absolute growth model; 3) using these models, we predicted an increase in the number of both potential and active grandmothers in the next 5 years.


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