This paper reports our experience in building time series models which connect the flows in two Icelandic rivers with the meteorological variables of precipitation and temperature. Two rivers with different hydrological characteristics were studied. In areas where precipitation may be either in the form of rain or snow linear models are inadequate to describe the relationship between the river and the meteorological variables. The methodology of threshold models recently developed seems to be well suited for taking into account the sharp difference in the relationship according to whether it is freezing or not. The possibility of identifying an alternative threshold variable is also explored.
In this paper we define subset threshold autoregressive models and suggest a simple algorithm for fitting them. The suggested algorithm is applied to simulated as well as real data. Two well-known time series are studied: the Canadian lynx data and Wolf's sunspot numbers. The fitted models are compared with the threshold models of Tong and Lim and with the subset bilinear models of Gabr and Subba Rao. Some statistical properties of these models are also studied. An examination of forecasting performance is included.
This paper contains a general introduction to Bioinformatics, theirs goals, objectives and their applied fields. Is then shed light on the real views of DNA of humans, some processors use mathematical and statistical analysis of the traditional purpose of these observations and to identify some features and characteristics. Graphical analysis of DNA is carried out in two and three dimensions. The interconnectedness among the sites of DNA is also analyzed as well as a spectral analysis. The attempt is also made to identify the order of such observations. Through this analytical study it is shown that DNA has a complex structure with interdependent with each other for long-term.
This paper deals with the fuzzy initial value problem and how to solve a linear fuzzy differential equation of first order when the initial condition is a triangle fuzzy number. This problem is then developed to the case when the initial condition is a trapezoidal fuzzy number. The paper includes also the issue of the representation of a system of linear fuzzy differential equations, a more general system of linear fuzzy differential equations is then proposed and the solution of this system is also given. An illustrative examples are given in order to consolidate the raised ideals.
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