The paper presents a new data inversion technique for the transient electromagnetic method (TEM) by converting measured signals into frequency domain. involves search such earth model parameters that there is consistency between synthetic and field data. We use an optimization method, where through numerical simulation at each iteration are determined in accordance with changing parameters. Num...

In this letter, we propose a recursive space time decoding method for orthogonal frequency division multiplexing (OFDM) systems exploiting multiple transmit antenna diversity when the channels are fast fading. We first develop a computationally efficient space-time decoding method involving a matrix inversion to mitigate the channel variation effect. We then further reduce the computational com...

the aim of this study is 3-d inversion of magnetic data acquired from the sorkheh-dizej iron-bearing region in zanjan province, iran, in order to determine the geometrical distribution of the buried magnetic sources. for this purpose, our program discretizes the subsurface region into vertical right rectangular prisms and uses the nonlinear marquardt-levenberg algorithm to optimize the unknown ...

Many natural phenomena, including geologic events and geophysical data, are fundamentally nonstationary exhibiting statistical variation that changes in space and time. Time-frequency characterization is useful for analyzing such data, seismic traces in particular. We present a novel time-frequency decomposition, which aims at depicting the nonstationary character of seismic data. The proposed ...

Emerging methods of hyperthermia cancer treatment require noninvasive temperature monitoring, and ultrasonic techniques show promise in this regard. Various tomographic algorithms are available that reconstruct sound speed or contrast profiles, which can be related to temperature distribution. The requirement of a high enough frequency for adequate spatial resolution and a low enough frequency ...

Time-frequency analysis is an important technology in seismic data processing and interpretation. To localize frequency content in time, we have developed a novel method for computing a time-frequency map for nonstationary signals using an iterative inversion framework. We calculated time-varying Fourier coefficients by solving a least-squares problem that uses regularized nonstationary regress...