data with high frequency have a particular type of none stationary that is called fractional none stationary. this property causes the emergence of long-term memory in financial time series with high frequency. the existence of long-term memory in cement industry time-series is studied in this paper at first and its presence will be confirmed in a high confidence level by two tests r/s and gph....

Investment is the process of investing money or capital for profit material results. The investor carefully calculates investment object to minimize losses and maximize profits. One essential objects futures price natural gas considered a commodity that plays vital role in Indonesian economy. movement prices can be modeled using time series model. data model believed have particular pattern fut...

The classic logistic model has provided a realistic of the behaviour Covid-19 in China and many East Asian countries. Once these countries passed peak, daily case count fell back, mirroring its initial climb symmetric way, just as predicts. However, Italy Spain most other Western countries, first wave epidemic was very different. back gradually from peak but remained stubbornly high. reason for...