A TIME-dependent PERIODIC coefficients (TDPC) model was proposed to analyze the Global Positioning System (GPS) TIME SERIES. Due to the variations of the amplitude and phase-lag of the GPS signals over TIME, we propose a TDPC to analyze the daily TIME SERIES. A new solution approach, where the serial correlations of the disturbances are eliminated by sequentially differencing the measurements, was used to estimate the model parameters using weighted least squares. As a numerical performance of the proposed method, the TIME SERIES of 19 permanent stations in the United States via the Website of Scripps Orbit and Permanent Array Center (SOPAC) between the 2000 and 2010 year was selected. The results show a decrease in the RMS values of the residuals, especially for the height components. Moreover, using the 90 simulated GPS data analysis, in which their noises were different combinations of white noise and flicker noise, we demonstrate that the proposed model can extract amplitude varying PERIODIC variabilities from GPS coordinate TIME SERIES.

The Urmia Lake is one of the important water bodies in the northwest of Iran that has a significant role in the economy and environment of the region. Recently, the lake is faced with a critical level reduction, which makes it important to evaluate the causes. In this regard understanding of the Lake's level behavior is necessary, which can be applied for mitigation measure to save it. This subject constructs objective of the present paper that applies the spectral analysis techniques to investigate harmonic periods of the Lake level TIME SERIES. For this, a combination of Multi Taper Method of spectral estimation and Singular Spectral Analysis were implemented. The results showed significant long-term periods in TIME SERIES. However due to limitation in the record length, the frequencies longer than about 20 years were applicable for the analyses. Also, comparing the reconstructed TIME SERIES of harmonic SERIES with the original TIME SERIES showed that although, harmonic oscillations are effective on level behavior of the lake, but declines of the recent years are not completely describable by these PERIODICities.

There are many studies discussing the correlation between air pollution and human health hazards. Yet, in Tehran there is not a survey using TIME SERIES methodology. Thus, we conducted a study based on TIME SERIES data on the topic in Tehran, Iran. Mean levels of NO, NO2, NOX, CO, 03, SO2 and PM10 (particulate matters smaller than 10micrometer in diameter) were measured in one station of Tehran's Air Quality Control Corporation and were used as main independent variables. Mean temperature, mean humidity, day of the week, month and season were considered as potential confounders and deaths in people older than 64 years in Tehran was the dependent variable. All the variables were measured during Mar. 1998 to Dec. 1999. Concentrations of air pollutants were different between seasons and so were the means of daily deaths. Out of main independent variables, SO2, CO and PM10 showed statistically significant relations with the dependent variable (P<0.05). After controling for confounders, there was 3.4%, 2.6% and 3.36% increase in death rates, respectively, for each interquartile ascending (increase from 25th centile to 75th centile) in association to the mentioned pollutant centile concentration. No autocorrelation between residuals was observed (r= -0.059). The study showed that meteorological variables can confound the relation between air pollution and rate of deaths per day.  

In this study, ground water level fluctuations and nitrate concentrations of kabudarahang aquifer were investigated with application of TIME SERIES models for modeling of ground water quantity and quality parameters. For data regarding the status of groundwater level and nitrate concentration fluctuations in project area, TIME SERIES models were used to forecast the groundwater level and nitrate concentration. Residual error analysis, comparison of observed and calculated ground water levels and nitrate concentrations performed and finally a prediction model for ground water conditions in Kabudarahang aquifer developed. Predicted values were calibrated by the Box-Jenkins, Holt Winters and extrapolation methods. A residual error analysis, based upon calculated and observed groundwater level and nitrate concentrations performed as a model verification tool and finally the Box Jenkins models were evaluated through Portmanteau method and Akaike information criterion. The model verification results showed that the SARIMA model is the optimum algorithm to simulate seasonal input data variables. Model results showed that the groundwater level in this aquifer will endure a 5 meter decline in three upcoming years and indicated that the maximum nitrate concentration would reach 50 mg/l in Bahman and Shahrivar of 1390.

Ultra-short pulse is a promising technology for achieving ultrahigh data rate transmission which is required to follow the increased demand of data transport over an optical communication system. Therefore, the propagation of such type of pulses and the effects that it may suffer during its transmission through an optical waveguide has received a great deal of attention in the recent years. We provide an overview of recent theoretical developments in a numerical modeling of Maxwell's equations to analyze the propagation of short laser pulses in photonic structures. The process of short light pulse propagation through 2D PERIODIC and quasi-PERIODIC photonic structures is simulated based on Finite-Difference TIME-Domain calculations of Maxwell’s equations.

Real-TIME embedded systems usually work in harsh environments with variable ambient temperature. As temperature has a significant impact on the processor reliability, thermal management is mandatory in many such systems, where it is critical to keep the processor temperature below some specified threshold. To achieve this goal, however, the system performance may adversely be affected. Our favorite performance objective in this paper is the minimization of the fraction of jobs which miss their deadline, regarding the thermal constraint. We propose a quasi-static approach based on dynamic voltage scaling: it first generates a number of thermally feasible speed schedules; one schedule for each range of ambient temperatures; then, at runTIME, the appropriate speed schedule is selected according to the ambient temperature. An online algorithm is also proposed to decide when the switching between the schedules occurs. The latter algorithm brings the processor temperature below specific values, so the newly selected speed schedule starts to work at the new scheduling wi hout violating the temperature constraint. The efficiencies of the proposed methods are investigated by simulation experiments.

In this paper we suggest a procedure for testing reversibility of TIME SERIES. Our approach is based on a necessary and sufficient condition for TIME reversibility of linear models. An attractive feature of the procedure is that in converse with other approaches it doesn’t require important assumptions, especially existence of moments of order higher than two. Our simulation confirms the procedure and some empirical examples are given.

The alternating current electroosmotic flow of a non-Newtonian power-law fluid is studied in a circular microchannel. A numerical method is employed to solve the non-linear Poisson-Boltzmann and the momentum equations. The main parameters which affect the flow field are the flow behavior index, the dimensionless zeta potential and the dimensionless frequency. At very low dimensionless frequencies (slow oscillatory motion, small channel size, or large effective viscosity), the plug-like velocity profiles similar to steady-state electroosmotic flow are observed at nearly all TIMEs. At very high dimensionless frequencies, the flow is shown to be restricted to a thin region near the channel wall, while the bulk fluid remains essentially stationary. Velocity distributions of pseudoplastics and dilatants may be widened at low values of the dimensionless frequency depending on the dimensionless zeta potential; at high dimensionless frequencies, however, both fluids represent enhanced velocity magnitudes with the dimensionless zeta potential. In the case of high shear rate and/or suddenly-started flows, pseudoplastics tend to produce higher velocities than dilatants. These two kinds of fluids may produce same velocity profiles relying on the value of the dimensionless zeta potential as well as the ratio of their flow behavior indexes.