A competitive neural network (NN) learned by the OLVQ1algorithm has the potential to produce images for land cover mapping.We propose an extended OLVQ1 that adds learning ratios to the originalalgorithm. Applying it to SPOT XS data, we show that higher mappingaccuracies can be obtained compared to those of conventional methods.

In this paper, four channel demultiplexer is designed using two-dimensional photonic crystal for Coarse Wavelength Division Multiplexing applications. The proposed demultiplexer consists of bus wave guide, output wave guide and a cavity. The channel selection is done by having a cavity with unique refractive index. The two dimensional finite difference time domain and plane wave expansion metho...

This paper describes a 1D Matlab finite difference time-domain (FDTD) code with a graphical user interface for visualization of the time-domain electromagnetic response. The program animates time-domain reflection and transmission of a Gaussian plane wave through one or two homogeneous material slabs. ß2001 John Wiley & Sons, Inc. Comput Appl Eng Educ 9: 136–147, 2001

During MR procedures majority of the radiofrequency (RF) power transmitted for imaging or spectroscopy is transformed into heat within the patient’s tissue as a result of resistive losses. In this work we evaluate the effect of a wide variety of receive-only insert geometry including cylinders and helmets with different trace widths on spin excitation field and SAR of a 7T TEM transmit coil.

Normally in the finite difference time domain (FDTD) technique, stationaly objects are modeled in a time domain simulation as a field propagates around them, and possibly inside these objects. Tbis paper illustrates a method in which EM fields and a moving object can be modeled using the FDTD technique. By using a techniqne of dielectric approximation and intermediate step field movement, it is...

In this paper, a method is presented for modeling sound propagation in rooms using a signal processing approach. Low order digital filters are designed to match to sound propagation transfer functions calculated from boundary material and air absorption data. The technique is applied to low frequency, finite difference time domain (FDTD) simulation of room acoustics and to real-time image-sourc...

Perfectly matched layer (PML) boundary conditions are derived for finite-difference timedomain analysis of acoustic waves within piezoelectric crystals. The robustness and effectiveness of the derived boundary conditions are demonstrated by simulating acoustic wave propagation in the bismuth germanate material system—a system in which simple absorbing boundary conditions cause instabilities. An...

Microwave ultra-wideband (UWB) radar systems are advantageous for their high-range resolution and ability to penetrate dielectric objects. Internal imaging of dielectric objects by UWB radar is a promising nondestructive method of testing aging roads and bridges and a noninvasive technique for human body examination. For these applications, we have already developed an accurate internal imaging...

The propagation and reflection of electromagnetic waves in a three-dimensional environment is simulated, and realistic images are produced using the resulting light distributions and reflectance functions. A finite difference time domain method is employed to advance the electric and magnetic fields in a scene. Surfaces containing wavelength scaled structures are created, the interaction of the...

Collisions play a major role in various models of musical instruments; one particularly interesting case is that of the guitar fretboard, the subject of this paper. Here, the string is modelled including effects of tension modulation, and the distributed collision both with the fretboard and individual frets, and including both effects of free string vibration, and under finger-stopped conditio...