⎯ The omni-directional sensitivity pattern of an integrated three dimensional acoustic sensor, composed of four hot-wire particle velocity sensors is analyzed theoretically and experimentally. We investigate the influence of the presence of the probe surface on the direction of the measured particle velocity measured by the sensors, and a description of the gas flow profile around the integrate...

OBJECTIVES Although directional microphones on a hearing aid provide a signal-to-noise ratio benefit in a noisy background, the amount of benefit is dependent on how close the signal of interest is to the front of the user. It is assumed that when the signal of interest is off-axis, users can reorient themselves to the signal to make use of the directional microphones to improve signal-to-noise...

Mobile terminals are often used indoor with the base station outdoors. At the mobile terminal the major part of the signal energy comes through openings in the building such as windows. Typically, only one of the sides in a room has windows, and seldom does a room have windows on all sides. Hence, the dominating signal can be expected to arrive at the mobile terminal from a narrow range of angl...

A direct nondiffractive tomographic algorithm is proposed for the determination of the crystal structure from real-space projections obtained by illuminating the sample with white x rays. This approach was applied to the pattern of the directional fine structure in absorption of white x rays recorded for a GaP crystal and allowed for a determination of the electron density distribution within t...

In this review paper, the design and implementation of antenna types in wide band frequencies for ocean communication are analysed. This work mainly concentrates on designing a high frequency wide band antenna which has high directivity, omni directional radiation pattern, small size and good time domain performances.

Targets and objects registration and tracking in a sequence of images play an important role in various areas. One of the methods in image registration is feature-based algorithm which is accomplished in two steps. The first step includes finding features of sensed and reference images. In this step, a scale space is used to reduce the sensitivity of detected features to the scale changes. Afterw...

directional simulation, among techniques for reliability analysis of engineering structures, is well known. in this context, directional simulation in load space, because of the considerable advantages of lower dimension of working space, is of considerable interest. as is expected due to structural resistance variability, the location of the relevant limit state(s) is no longer constant and mu...

high temperatures are often encountered in almost all of the combustion systems, therefore, thermal radiation heat transfer can influence the droplets heat up rate and consequently their life time. in this paper, the effect of thermal radiation heat transfer is investigated for two cases of directional and spherically symmetric illuminations. the flow and temperature fields insdie and outside o...

This article has focused on evaluation and identification of effective parameters in positioning performance with an odometry approach of an omni-directional mobile robot. Although there has been research in this field, but in this paper, a new approach has been proposed for mobile robot in positioning performance. With respect to experimental investigations of different parameters in omni-dire...