Case Analysis: Financial viability for the commercialization of physicochemical testing services at the Antioquia Liquor and Alcohol Factory (ALAF)

2021 ◽  
Vol 37 (71) ◽  
pp. e2110690
Author(s):  
Carmelina Patrón Mejía ◽  
Carlos Mario Durango Yepes

The purpose of this work is to evaluate the profitability of the market for physicochemical testing of alcoholic beverages, which the Physicochemical Laboratory of the Liquor de Antioquia Factory (FLA) intends to enter, according to the transformation in its legal nature. The methodology that includes the costing of the tests using cost accounting and the analytical procedures used by the laboratory. For the construction of the cash flow of the project for the sale of the physicochemical tests, it was necessary to search and consolidate information concerning the inventory of fixed assets of the laboratory and the entry of annual samples from the different areas of the FLA. The AutoRegressive Moving Average (ARMA) model is used as the demand projection method. The results reveal that, although restricted and specialized, the physicochemical testing market may generate, under certain scenarios, a return on investment that allows the self-sustainability, viability and competitiveness of the physicochemical laboratory over time.

2011 ◽  
Vol 187 ◽  
pp. 92-96 ◽  
Author(s):  
Zhi Kai Huang ◽  
De Hui Liu ◽  
Xing Wang Zhang ◽  
Ling Ying Hou

Image denoising is one of the classical problems in digital image processing, and has been studied for nearly half a century due to its important role as a pre-processing step in various image applications. In this work, a denoising algorithm based on Kalman filtering was used to improve natural image quality. We have studied noise reduction methods using a hybrid Kalman filter with an autoregressive moving average (ARMA) model that the coefficients of the AR models for the Kalman filter are calculated by solving for the minimum square error solutions of over-determined linear systems. Experimental results show that as an adaptive method, the algorithm reduces the noise while retaining the image details much better than conventional algorithms.


2005 ◽  
Vol 12 (1) ◽  
pp. 55-66 ◽  
Author(s):  
W. Wang ◽  
P. H. A. J. M Van Gelder ◽  
J. K. Vrijling ◽  
J. Ma

Abstract. Conventional streamflow models operate under the assumption of constant variance or season-dependent variances (e.g. ARMA (AutoRegressive Moving Average) models for deseasonalized streamflow series and PARMA (Periodic AutoRegressive Moving Average) models for seasonal streamflow series). However, with McLeod-Li test and Engle's Lagrange Multiplier test, clear evidences are found for the existence of autoregressive conditional heteroskedasticity (i.e. the ARCH (AutoRegressive Conditional Heteroskedasticity) effect), a nonlinear phenomenon of the variance behaviour, in the residual series from linear models fitted to daily and monthly streamflow processes of the upper Yellow River, China. It is shown that the major cause of the ARCH effect is the seasonal variation in variance of the residual series. However, while the seasonal variation in variance can fully explain the ARCH effect for monthly streamflow, it is only a partial explanation for daily flow. It is also shown that while the periodic autoregressive moving average model is adequate in modelling monthly flows, no model is adequate in modelling daily streamflow processes because none of the conventional time series models takes the seasonal variation in variance, as well as the ARCH effect in the residuals, into account. Therefore, an ARMA-GARCH (Generalized AutoRegressive Conditional Heteroskedasticity) error model is proposed to capture the ARCH effect present in daily streamflow series, as well as to preserve seasonal variation in variance in the residuals. The ARMA-GARCH error model combines an ARMA model for modelling the mean behaviour and a GARCH model for modelling the variance behaviour of the residuals from the ARMA model. Since the GARCH model is not followed widely in statistical hydrology, the work can be a useful addition in terms of statistical modelling of daily streamflow processes for the hydrological community.


Symmetry ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 324 ◽  
Author(s):  
Dabuxilatu Wang ◽  
Liang Zhang

Autoregressive moving average (ARMA) models are important in many fields and applications, although they are most widely applied in time series analysis. Expanding the ARMA models to the case of various complex data is arguably one of the more challenging problems in time series analysis and mathematical statistics. In this study, we extended the ARMA model to the case of linguistic data that can be modeled by some symmetric fuzzy sets, and where the relations between the linguistic data of the time series can be considered as the ordinary stochastic correlation rather than fuzzy logical relations. Therefore, the concepts of set-valued or interval-valued random variables can be employed, and the notions of Aumann expectation, Fréchet variance, and covariance, as well as standardized process, were used to construct the ARMA model. We firstly determined that the estimators from the least square estimation of the ARMA (1,1) model under some L2 distance between two sets are weakly consistent. Moreover, the justified linguistic data-valued ARMA model was applied to forecast the linguistic monthly Hang Seng Index (HSI) as an empirical analysis. The obtained results from the empirical analysis indicate that the accuracy of the prediction produced from the proposed model is better than that produced from the classical one-order, two-order, three-order autoregressive (AR(1), AR(2), AR(3)) models, as well as the (1,1)-order autoregressive moving average (ARMA(1,1)) model.


2013 ◽  
Vol 462-463 ◽  
pp. 259-266
Author(s):  
Xin Zhao ◽  
Hong Lei Qin ◽  
Li Cong

This paper proposes a novel adaptive integrated navigation filtering method based on autoregressive moving average (ARMA) model and generalized autoregressive conditional heteroscedasticity (GARCH) model. The main idea in this study is to employ ARMA/GARCH model to estimate statistical characteristics of filtering residual series online, namely, the conditional mean and conditional standard deviation, and then the filter parameters are adaptively adjusted based on forecasted results of ARMA/GARCH model in order to improve the reliability of the system when there are abnormal disturbance and other uncertain factors in real condition. On this basis, experiment is used to verify the validity of the method. The simulation results demonstrate that the ARMA/GARCH model can well capture the unusual condition of GPS receiver output, and this adaptive filtering method can effectively improve the reliability of the system.


2011 ◽  
Vol 403-408 ◽  
pp. 2800-2804
Author(s):  
En Wei Chen ◽  
Yi Min Lu ◽  
Zheng Shi Liu ◽  
Yong Wang

Time-varying parameters identification in linear system is considered, which can be changed into time-invariant coefficient polynomials after Taylor expansion. Using response data to establish the time-varying autoregressive moving average (TV-ARMA) model, then utilizing least-square algorithm to obtain time-invariant coefficients of time-varying parameters. According to error analysis, to reduce errors and improve accuracy, the estimation time is divided into small internals and the above method is used in each interval. Simulation shows that, under certain error condition, the time-varying parameters obtained by the method have good agreement with the theoretical values; the measures taken have strong anti-interference and high efficiency.


Author(s):  
Zheng Fang ◽  
David L. Dowe ◽  
Shelton Peiris ◽  
Dedi Rosadi

We investigate the power of time series analysis based on a variety of information-theoretic approaches from statistics (AIC, BIC) and machine learning (Minimum Message Length) - and we then compare their efficacy with traditional time series model and with hybrids involving deep learning. More specifically, we develop AIC, BIC and Minimum Message Length (MML) ARMA (autoregressive moving average) time series models - with this Bayesian information-theoretic MML ARMA modelling already being new work. We then study deep learning based algorithms in time series forecasting, using Long Short Term Memory (LSTM), and we then combine this with the ARMA modelling to produce a hybrid ARMA-LSTM prediction. Part of the purpose of the use of LSTM is to seek capture any hidden information in the residuals left from the traditional ARMA model. We show that MML not only outperforms earlier statistical approaches to ARMA modelling, but we further show that the hybrid MML ARMA-LSTM models outperform both ARMA models and LSTM models.


2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Manfei Zhang ◽  
Yimeng Wang ◽  
Xiao Wang ◽  
Weibo Zhou

Accurate and reliable prediction of groundwater depth is a critical component in water resources management. In this paper, a new method based on coupling wavelet decomposition method (WA), autoregressive moving average (ARMA) model, and BP neural network (BP) model for groundwater depth forecasting applications was proposed. The relative performance of the proposed coupled model (WA-ARMA-BP) was compared to the regular autoregressive integrated moving average (ARIMA) and BP models for annual average groundwater depth forecasting using leave-one-out cross-validation (LOO-CV). The variables used to develop and validate the models were average groundwater depth data recorded from 1981 to 2010 in Jinghui Canal Irrigation District in the northwest of China. It was found that the WA-ARMA-BP model provided more accurate annual average groundwater depth forecasts compared to the ARIMA and BP models. The results of the study indicate the potential of the WA-ARMA-BP model in forecasting nonstationary time series such as groundwater depth.


1980 ◽  
Vol 7 (1) ◽  
pp. 185-191
Author(s):  
W. J. Stolte

Probabilistic models have become important hydrologic tools. However, increasing model complexity makes the connections between the model and the physical world more and more vague. This can lead to a de-emphasis of engineering judgment, since model validity is easily assumed when even partial verification must await future occurrences. A simple autoregressive model was used to generate stochastic flow sequences for the dam and reservoir being constructed on the Red Deer River in Alberta. The results from this model were compared with those obtained from a more complex autoregressive moving average (ARMA) model. Both models have similar deficiencies. It is concluded that since stochastic generation can never represent future conditions with certainty, the common practice of basing the hydrologic design of reservoirs on actually recorded data is usually the most valid procedure. However, stochastic streamflow generation can be used to give valuable probabilities of reservoir storage failure.


2019 ◽  
Author(s):  
Nicola Bragazzi

BACKGROUND Table tennis is a popular sport, practiced worldwide. In particular, it is the most popular racquet sport in the world and ranks second in terms of participation. Over 10-18 million players compete in many tournaments each year. OBJECTIVE However, little is known about the table tennis related web activities. METHODS Google Trends (GT), a freely online available tool that tracks and monitor web searches, was mined from 2004 to today worldwide, using table tennis as a keyword. The searches volumes were correlated with country ranking (overall and broken down for gender). An autoregressive moving-average (ARMA) model was used to model the GT-generated data. RESULTS Table tennis resulted the second most popular racquet sport being googled worldwide. Interest for table tennis has slightly decreased over the time with table tennis-related web activities exhibiting a cyclic pattern. The best ARMA model which fits the trend of Internet searches is an ARMA(6,5). The most related searches concerned equipment and sports products for playing table tennis, famous athletes, other team sports and scheduled tournaments. Country ranking (both overall and broken down for gender) well correlated with GT-based RSV. CONCLUSIONS Despite its limitations, GT appears to have some degrees of utility in tracking, monitoring in real time and forecasting/nowcasting table tennis related web searches.


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