A model for radar images and its application to adaptive digital filtering of multiplicative noise

Standard image processing techniques which are used to enhance noncoherent optically produced images are not applicable to radar images due to the coherent nature of the radar imaging process. A model for the radar imaging process is derived in this paper and a method for smoothing noisy radar images is also presented. The imaging model shows that the radar image is corrupted by multiplicative noise. The model leads to the functional form of an optimum (minimum MSE) filter for smoothing radar images. By using locally estimated parameter values the filter is made adaptive so that it provides minimum MSE estimates inside homogeneous areas of an image while preserving the edge structure. It is shown that the filter can be easily implemented in the spatial domain and is computationally efficient. The performance of the adaptive filter is compared (qualitatively and quantitatively) with several standard filters using real and simulated radar images.     

Performance evaluation of an acrylic mirror booster solar still for neera concentration in jaggery-making industry

A single-basin solar still was constructed from locally available materials to concentrate palm tree juice (neera) for jaggery-making application. The performance of the still was tested with and without an acrylic mirror booster on both partially cloudy and clear sunshine days. About 73% of water content from neera was evaporated within 2 days by using the mirror booster technique in clear sunshine days. Distilled water of about 7.26 l was extracted from 10 l of neera with the mirror booster condition. Wind velocity showed a considerable effect on neera juice temperature and water vapour temperature during partially cloudy conditions. The calculated efficiency of the still with the mirror booster technique was 36.53% in clear sunshine conditions. The calculated energy conservation for the neera concentration process by using the mirror booster solar still was about 16408 kJ.     

Experimental Investigation on the Performance of a Solar Still Using SiO2 Nanoparticles /Jatropha curcas L

Silicon - Now, enticing systematic civic since everywhere the world is used in green synthesis and benefit of the simple is eco-friendly with an emergent method of producing nanoparticles (NPs)....     

Effect of Ar ion irradiation on structural and optical properties of e-beam evaporated cadmium telluride thin films

CdTe thin films were prepared using e-beam evaporation technique. The prepared films were irradiated by Ar⁺ ions at different fluencies using multipurpose aluminum (Al) probe as in-situ. This could also be used in ion bombardment for cleaning the substrate prior to coating. The as grown and Ar⁺ ion irradiated films were confirmed to be of polycrystalline nature with X-ray technique. Ar⁺ ion irradiation enhances the growth of (1 1 1) oriented CdTe crystals and the Cd enrichment on the surface of CdTe thin films. Higher Ar⁺ ion flux helps to grow (2 2 0) oriented CdTe thin film. A considerable change in structural parameters like crystallite size, lattice parameter, internal strain, etc. could be observed as a result of high Ar⁺ ion flux. The applied in-plan stress in both as grown and irradiated film was identified to be of tensile nature. The applied stress was observed between 0.016 and 0.067 GPa for all Ar⁺ ion irradiated samples. As a result of the Ar⁺ ion irradiation, the in-plan stress varies between 1.38×10⁹ and 5.58×10⁹ dyn/cm². The observed bad gap was increased for higher Ar⁺ ion flux. It shows the effect of Ar⁺ ion irradiation on the modifications of optical properties. The observed results were encouraging on the use of simple multipurpose Al probe for Ar⁺ ion irradiation process as in-situ.     

On improving the computational efficiency of digital lightwave linksimulation

Monte Carlo simulation can be used to estimate the bit error rate (BER) in digital lightwave communication links. However, when the link includes an avalanche photodetector (APD) receiver and is operating at a low BER, Monte Carlo simulation requires excessive execution time unless assumptions are made about the APD statistics. Techniques are presented that reduce the computational resources required to estimate the BER for these systems by two orders of magnitude. The speed-up is achieved by developing anew, more efficient random number generation algorithm for APD shot noise and by applying a tail extrapolation technique to the conditional distributions at the sample-and-decide input in the receiver. Receiver thermal noise is handled analytically. Accurate BER estimates for an NRZ direct-detection system are obtained in approximately 1.5 CPU hours on a VAXstation II using a combination of these techniques     

A control and management network for wireless ATM systems

This paper describes the design of a control and management network (orderwire) for a mobile wireless Asynchronous Transfer Mode (ATM) network. This mobile wireless ATM network is part of the Rapidly Deployable Radio Network (RDRN). The orderwire system consists of a packet radio network which overlays the mobile wireless ATM network. Each network element in this network uses Global Positioning System (GPS) information to control a beamforming antenna subsystem which provides for spatial reuse. This paper also proposes a novel Virtual Network Configuration (VNC) algorithm for predictive network configuration. A mobile ATM Private Network–Network Interface (PNNI) based on VNC is also discussed. Finally, as a prelude to the system implementation, results of a Maisie simulation of the orderwire system are discussed. This revised version was published online in June 2006 with corrections to the Cover Date.     

An update on software packages for simulation of communicationsystems (links)

An update is provided of the software package for link simulation that were described in the January 1984 issue of this journal (P. Balaban, et al., ibid., vol.2, no.1, pp.1-8). The packages covered are SYSTID, TOPSIM, CHAMP, ICS, ICSSM, BLOSIM, and CLASS. Three new software packages are reviewed: MODEM, WCS, and BOSS. Recent trends in software packages for simulation-based analysis and design of communication links are also discussed     

Identification of corn fields using multidate radar data

Airborne C- and L-band radar data acquired over a test site in western Kansas were analyzed to determine corn-field identification accuracies obtainable using single-channel, multichannel, and multidate radar data. An automated pattern-recognition procedure was used to classify 144 fields into three categories: corn, pasture land, and bare soil (including wheat stubble and fallow). Corn fields were identified with accuracies ranging from 85% for single channel, single-date data to 100% for single-channel, multidate data. The effects of radar parameters such as frequency, polarization, and look angle as well as the effects of soil moisture on the classification accuracy are also presented.     

Synthesis of In2O3 Thin Films from Indium Thin Film by Hot-Water Oxidation Method

Radio-frequency (RF)-sputtered indium thin films were prepared and processed in ultrapure water at 368 K (95 °C) for various time durations. The processed samples were poor in crystalline quality and indexed as cubic phase for the samples processed for more than 12 hours. A rhombohedral to cubic phase was also observed. Photoluminescence (PL) and Raman spectra showed few dominant peaks at ~385, ~515, and ~675 and at ~203 and 495 cm⁻¹ as oxygen deficient cubic In₂O₃ with nanostructured In₂O₃, respectively.