structural time
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2021 ◽  
Vol 10 (2) ◽  
pp. 1-17
Author(s):  
Ondrej Bednar

I have employed the Bayesian Structural Time Series model to assess the recent interest rate hike by the Czech Central Bank and its causal impact on the Koruna exchange rate. By forecasting exchange rate time series in the absence of the intervention we can subtract the observed values from the prediction and estimate the causal effect. The results show that the impact was little and time limited in one model specification and none in the second version. It implies that the Czech Central Bank possesses the ability to diverge significantly from the Eurozone benchmark interest rate at least in the short term. It also shows that the interest rate hike will not be able to curb global inflation forces on the domestic price level.


2021 ◽  
Vol 2131 (3) ◽  
pp. 032026
Author(s):  
A Kurnosov

Abstract The article discusses the main characteristics of complex systems, as well as the structures, domains and interactions occurring in the course of evolution. The main properties of complex systems are defined to include openness, non-ergodicity, disequilibrium, activity and multiplicity of goals. The classification attributes are defined to include free energy, anthropic factor, incomplete observability, computational irreducibility, dominant coded interactions, dynamic structure and transformable environments. A variety of primary entities, which form complex systems, are represented by two classes, possible individuals and abstract individuals. The space-time structure as a 6D continuum is formulated; spatial and temporal vacuums and quanta of interaction are defined. The three-dimensional time is presented in terms of three orthogonal components: coordinate time, structural time and discrete time. The coordinate time corresponds to the variability of a system when individuals move in space; the structural time corresponds to the variability of a system when the structure of individuals changes; the discrete time corresponds to the variability of the system caused by informational interaction between or within individuals. A model of a one-time ideal event and a continuous event is defined. The interaction between individuals is presented through a two-way reflexive model of cyclic interaction of an actor and an acceptor. The occurrence of post-causes and post-effects of physical interactions is shown to result in unpredictable chains of effects. The essence of the predictive temporal analytics method is presented. The use of the method involves the construction of a six-dimensional hypergraph of cause-and-effect relations with subsequent analysis of a body of causes and effects. The optimal way of evolution of a system is considered a way that maximizes diversity (in terms of liberty of actions, states, goals achieved) and minimizes the energy costs in a certain time perspective.


2021 ◽  
Vol 10 (3) ◽  
Author(s):  
Sophia Wang ◽  
Connor Lee ◽  
XL Pang

The western U.S. has been experiencing a mega-scale drought since 2000. By killing trees and drying out forests, the drought triggers widespread wildfire activities. In the 2020 California fire season alone, more than 10.3 million acres of land were burned and over 10000 structures were damaged. The estimated cost is over $12 billion. Drought also devastates agriculture and drains the social and emotional well-being of impacted communities.  This work aims at predicting the occurrence and severity of drought, and thus helping mitigate drought related adversaries. A machine learning based framework was developed, including time series data collection, model training, forecast and visualization. The data source is from the National Drought Monitor center with FIPS (Federal Information Processing Standards) geographic identification codes. For model training and forecasting, a Bayesian structural time series (BSTS) based statistical model was employed for a time-series forecasting of drought spatially and temporally. In the model, a time-series component captures the general trend and seasonal patterns in the data; a regression component captures the impact of the drought in measurements such as severity of drought, temperature, etc. The statistical measure, Mean Absolute Percentage Error, was used as the model accuracy metric. The last 10 years of drought data up to 2020-09-01 was used for model training and validation. Back-testing was implemented to validate the model . Afterwards, the drought forecast was generated for the upcoming 3 weeks of the United States based on the unit of county level. 2-D heat maps were also integrated for visual reference.   


2021 ◽  
Vol 17 (8) ◽  
pp. e1009303
Author(s):  
Jason Liu ◽  
Daniel J. Spakowicz ◽  
Garrett I. Ash ◽  
Rebecca Hoyd ◽  
Rohan Ahluwalia ◽  
...  

The development of mobile-health technology has the potential to revolutionize personalized medicine. Biomedical sensors (e.g. wearables) can assist with determining treatment plans for individuals, provide quantitative information to healthcare providers, and give objective measurements of health, leading to the goal of precise phenotypic correlates for genotypes. Even though treatments and interventions are becoming more specific and datasets more abundant, measuring the causal impact of health interventions requires careful considerations of complex covariate structures, as well as knowledge of the temporal and spatial properties of the data. Thus, interpreting biomedical sensor data needs to make use of specialized statistical models. Here, we show how the Bayesian structural time series framework, widely used in economics, can be applied to these data. This framework corrects for covariates to provide accurate assessments of the significance of interventions. Furthermore, it allows for a time-dependent confidence interval of impact, which is useful for considering individualized assessments of intervention efficacy. We provide a customized biomedical adaptor tool, MhealthCI, around a specific implementation of the Bayesian structural time series framework that uniformly processes, prepares, and registers diverse biomedical data. We apply the software implementation of MhealthCI to a structured set of examples in biomedicine to showcase the ability of the framework to evaluate interventions with varying levels of data richness and covariate complexity and also compare the performance to other models. Specifically, we show how the framework is able to evaluate an exercise intervention’s effect on stabilizing blood glucose in a diabetes dataset. We also provide a future-anticipating illustration from a behavioral dataset showcasing how the framework integrates complex spatial covariates. Overall, we show the robustness of the Bayesian structural time series framework when applied to biomedical sensor data, highlighting its increasing value for current and future datasets.


Author(s):  
Paul de Nailly ◽  
Etienne Côme ◽  
Allou Samé ◽  
Latifa Oukhellou ◽  
Jacques Ferriere ◽  
...  

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11537
Author(s):  
Navid Feroze ◽  
Kamran Abbas ◽  
Farzana Noor ◽  
Amjad Ali

Background COVID-19 is currently on full flow in Pakistan. Given the health facilities in the country, there are serious threats in the upcoming months which could be very testing for all the stakeholders. Therefore, there is a need to analyze and forecast the trends of COVID-19 in Pakistan. Methods We have analyzed and forecasted the patterns of this pandemic in the country, for next 30 days, using Bayesian structural time series models. The causal impacts of lifting lockdown have also been investigated using intervention analysis under Bayesian structural time series models. The forecasting accuracy of the proposed models has been compared with frequently used autoregressive integrated moving average models. The validity of the proposed model has been investigated using similar datasets from neighboring countries including Iran and India. Results We observed the improved forecasting accuracy of Bayesian structural time series models as compared to frequently used autoregressive integrated moving average models. As far as the forecasts are concerned, on August 10, 2020, the country is expected to have 333,308 positive cases with 95% prediction interval [275,034–391,077]. Similarly, the number of deaths in the country is expected to reach 7,187 [5,978–8,390] and recoveries may grow to 279,602 [208,420–295,740]. The lifting of lockdown has caused an absolute increase of 98,768 confirmed cases with 95% interval [85,544–111,018], during the post-lockdown period. The positive aspect of the forecasts is that the number of active cases is expected to decrease to 63,706 [18,614–95,337], on August 10, 2020. This is the time for the concerned authorities to further restrict the active cases so that the recession of the outbreak continues in the next month.


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