Showing papers by "Amirkabir University of Technology published in 1993"
66 citations
12 Oct 1993
TL;DR: In this article, an extensive curve fitting for the distribution of individual multipath components' amplitudes using elaborate tests based on the Kolmogorov-Smirnov and Wilcoxon procedures is presented.
Abstract: Small-scale and large-scale variations of signal amplitude for wideband data collected at two office buildings have been investigated. The data base includes 12000 impulse response estimates which were obtained by inverse Fourier transforming of the channel's frequency response profiles. Extensive curve fitting for the distribution of individual multipath components' amplitudes using elaborate tests based on the Kolmogorov-Smirnov and Wilcoxon procedures shows that amplitude fading is lognormal for both local and global data. For the local data, the lognormal, Nakagami, and Rayleigh distributions passed the Kolmogorov-Smirnov test with a 90% confidence level for 76%, 36%, and 13% of cases, respectively. For global data the Wilcoxon test showed that with 99% confidence lognormal is better than Nakagami, and with 94% confidence Nakagami fits the data better than Rayleigh. After establishing the lognormality of signal amplitude fading in these environments, a two-dimensional Gaussian distribution for simulating the log- amplitudes of spatially-adjacent profiles has been proposed and implemented.
55 citations
TL;DR: For improved bio and water compatibility laser induced graft copolymerization of acrylamide (AAm) onto the surface of EPR vulcanizates has been attempted using a line-tunable pulsed CO 2 laser as mentioned in this paper.
29 citations
TL;DR: In this article, the effect of forced convection inside the solar still on the coefficients of heat and mass transfer was studied using a mathematical model through a computer program, and good agreement was obtained between the two results.
27 citations
28 Oct 1993
TL;DR: A cluster separation index has been applied to a variety of commonly-used EMG (electromyelogram) features for movement control of a prosthetic arm and it has been shown that, for small window sizes, the Integral of the Absolute Value of the EMG is the most suitable feature, while the first coefficient of the Auto Regressive mode1 provides greater class separability.
Abstract: A cluster separation index has been applied to a variety of commonly-used EMG (electromyelogram) features for movement control of a prosthetic arm. It has been shown that, for small window sizes, the Integral of the Absolute Value (IAV) of the EMG is the most suitable feature, while, for hrge window sizes, the first coefficient of the Auto Regressive (AR) mode1 of the EMG provides greater class separability. Suggestions for future work are discussed.
14 citations
TL;DR: In this article, the results have shown that chemical bonding between polymer and the cell wall component lead to better strength properties in the composites, and their composites have been tested for their physical and mechanical properties.
14 citations
TL;DR: In this article, post-irradiation degradation of isotactic polypropylene irradiated by Co60-γ-ray has been followed for 12 months, showing that the degradation occurs via chain scission mechanism.
13 citations
TL;DR: In this paper, a finite element method based on variational formulation was proposed to analyze the shell of revolution on an elastic foundation, where the elastic foundation is assumed to be either in distributed form extending over the entire surface of the element or in ring form applied at a nodal point.
4 citations
16 Aug 1993
TL;DR: A fuzzy method to vary and modify the critical coefficients ETA and ALPHA involved with the feed forward multilayer neural network (FF network) to raise the network learning speed is proposed.
Abstract: We have proposed a fuzzy method to vary and modify the critical coefficients ETA and ALPHA involved with the feed forward multilayer neural network (FF network) to raise the network learning speed. In fact a fuzzy controller has been designed in this regard in order to accept the absolute and the change of error values as its inputs to determine the proper ETA and ALPHA coefficients. This can be done with the aid of the appropriate rule bases that result from the observation and analysis of neural network behavior during its learning interval. >
16 Aug 1993
TL;DR: In this paper, a new design methodology to integrate digital protection relays is proposed to solve the timing problems involved with the conventional integrated protection systems, and the proposed algorithms not only have led to an overall fast protection response, as well as integration advantages, but also have offered possibility of ommitting conventional different relays with their abnormal characteristics.
Abstract: We have proposed a new design methodology to integrate digital protection relays. We have solved the timing problems involved with the conventional integrated protection systems. The proposed algorithms not only have led to an overall fast protection response, as well as integration advantages, but also have offered possibility of ommitting conventional different relays with their abnormal characteristics (CT saturation, restraint harmonic extraction, etc.). >
TL;DR: In this paper, the fission track age and uranium content of various rocks such as Apatite, Sphene, Obsidian, Calcite and Fluorite from different region of the country has been determined.