In this paper, we propose a modification of the multiple sinusoidal model such that periodic data observed with the presence of a trend component can be analyzed. In particular, we work with a linear trend model. But it can be developed similarly for the polynomial trend and the frequency model also. We consider the problem of estimation of frequency and amplitude parameters observed with a lin...

where it is assumed that the expected value of X(t) is zero. There is no commonly accepted precise definition for trend, but it is usually spoken of as a nonrandom (deterministic) smooth function representing long-term movement or systematic variations in a series (for example, Priestley (1981) refers to a trend as “. . . a tendency to increase (or decrease) steadily over time . . . [or to] flu...

Detrended fluctuation analysis (DFA) is a scaling analysis method used to estimate long-range power-law correlation exponents in noisy signals. Many noisy signals in real systems display trends, so that the scaling results obtained from the DFA method become difficult to analyze. We systematically study the effects of three types of trends--linear, periodic, and power-law trends, and offer exam...

This study analyzes changing trends in U.S. health spending and concludes that although the long-term growth trend has been a good predictor of future spending, periodic differences in the growth trend are important. Of particular concern is the rapid acceleration in health spending beginning in 1998. If left unchecked, the current growth rate will result in almost 24 percent of GDP spent on he...

BACKGROUND The purpose of this study was to evaluate the effects of benzalkonium (BAK)-free travoprost monotherapy administered for 3 years on intraocular pressure and visual field performance. METHODS The intraocular pressure of 76 patients with normal tension glaucoma was monitored every 1-3 months. A Humphrey visual field test was performed every 6 months after treatment and compared with ...

introduction: dissertations are important part of medical practitioner students training modules and may increase their knowledge and skills in the research methodology. this research was conducted to study ten research methodology indexes in medical student's dissertations in kermanshah university of medical sciences from 1988 to 2005. materials and methods: this is an analytical-descriptive s...

in the present paper the linear oscillator in r3 with z =constanthas been considered. the aim is to determine the necessary conditions forthe persistence of periodic solutions under discontinuous perturbations. a newapproach based on a computational method has been used. at the end weapply our method on an example.