scholarly journals Towards a Concept Design for a LOFAR

2002 ◽  
Vol 199 ◽  
pp. 484-485 ◽  
Author(s):  
Jaap D. Bregman
Keyword(s):  
Data Processing ◽  
High Performance ◽  
Phased Array ◽  
Low Frequency ◽  
Software Radio ◽  
Concept Design ◽  
Digital Beamforming ◽  
Sky Survey ◽  
Array Technology ◽  
The Cost

The LOw Frequency ARray is a Digital Software Radio Telescope under study by the NFRA and the NRL. A scaleable architecture is proposed for the antenna stations of an aperture synthesis array operating in the 10 — 160 MHz frequency band. The use of advanced phased array technology with digital beamforming results in a multi-beam capability of up to 64 beams, which cover together about a steradian on the sky, and can be placed such that all relevant science objects are covered simultaneously. Based on the fast expansion of high performance processing technology, it is just after 2003 that signal and data processing will no longer dominate the cost of LOFAR in producing a confusion limited sky survey at the mJy level.

Phased Array UT Technology for Nuclear Pipe Inspection

2002 ◽  
Author(s):  
Doug E. MacDonald ◽  
Mark A. Dennis ◽  
Jeff L. Landrum ◽  
Greg P. Selby
Keyword(s):  
Phased Array ◽  
Pipe Inspection ◽  
Intergranular Stress Corrosion ◽  
Dissimilar Metal ◽  
Array Technology ◽  
Phased Array Ultrasound ◽  
Array Ultrasound ◽  
The Cost ◽  
Intergranular Stress Corrosion Cracking ◽  
Technique Development

Phased array UT technologles have been applied to improve pipe inspection speed and reliability. Recent results on similar and dissimilar metal welds show clear, accurate, and fast results. Phased array ultrasound has been developed and commercialized already for high-value, inspections such as turbines and boiling water reactor (BWR) core shrouds. This paper describes how the benefits of phased array technology are being extended for application to piping examinations, including the detection and length sizing of intergranular stress corrosion cracking (IGSCC) in austenitic and dissimilar metal welds. The costs associated with pipe inspections contain factors related to the duration and reliability of inspections. The phased array improvements in flaw detectability, sizing accuracy, and speed, will lower the cost and increase the reliability of piping examinations by reducing qualification costs, radiation exposure, re-scans, and repairs. EPRI is encouraging the deployment of phased array pipe inspection technology by coordinating the technique development with several vendors so that when the technique is qualified, the vendor(s) will be ready to deliver it. This approach has already worked well for other phased array applications. As more vendors develop phased array capabilities, the deployment task becomes easier. To encourage the use of this technology, EPRI has developed and qualified through the Performance Demonstration Initiative (PDI) an automated phased array procedure for piping weld inspection.

scholarly journals Μελέτη, ανάλυση και βελτίωση της λειτουργίας αερομεταφερόμενου ραντάρ συνθετικής απεικόνισης (SAR) χαμηλών συχνοτήτων

2002 ◽  
Author(s):  
Αθανάσιος Πότσης
Keyword(s):  
Data Processing ◽  
High Performance ◽  
Dynamic Range ◽  
Low Frequency ◽  
Low Noise ◽  
Electromagnetic Spectrum ◽  
System Operation ◽  
Low Frequencies ◽  
Technological Advances ◽  
Sar Data

Because of its high resolution, frequency scattering properties and indifference to day/night or cloud cover, Synthetic Aperture Radar (SAR) has become into vogue in the last years. The field of SAR remote sensing has changed dramatically with the operational introduction of new high performance signal processing techniques and new operational modes, like the polarimetry in 1980’s and the interferometry in 1990’s. Additionally, technological advances in antenna design, low noise amplifiers, band-pass filters, digital receiver technology and high frequency digital sampling devises, increase the availability and the performance of airborne as well as spaceborne SAR sensors. All these technological advances result to real time SAR system operation and in most of the frequency bands of the electromagnetic spectrum. These advanced hardware components combined with the new radar techniques result to large variety of operational and research applications. In several of the new coming applications there is the need for a SAR system to penetrate vegetation and foliage. As a result of this, a new class of SAR systems, using low frequencies, has emerged. The combination of low frequency with high bandwidth allows a variety of new military as well as civilian applications. In the frame of this thesis, several hardware and software modifications made in the E-SAR P-Band system operated by DLR aiming the improvement of the collected and processed data quality is described. The basic P-Band inherent problems like the low Signal-To-Noise-Ratio (SNR), the presence of Radio Frequency Interferences (RFI) as well as the high dynamic range of the backscattered signal are addressed. A new mode of operation called “Listen Only” (LO) channel mode gave us the unique opportunity to study and analyze the special characteristics of the interfering signals and the nature of the low frequency backscattered signal. Based on this analysis new RFI suppression algorithms have been developed and the system operation parameters have been set to the correct value resulting to high quality collected data. The effect of RFI signals in fully polarimetric SAR data processing and applications are analyzed in detail. One of the principal items of this thesis is the development of a new robust sub-aperture algorithm for improved Motion Compensation (MoCo) in wide azimuth beam SAR data processing. The new algorithm is incorporated to the Extended Chirp Scaling SAR data processing algorithm. The improved MoCo algorithm results to focused images with high SNR, contrast, higher resolution and better geometric correctness. The performance and the correction accuracy of the proposed algorithms are analyzed by using mainly real data collected by the E-SAR system of DLR.

Application of Phased Array Technology for Identification of Low Frequency Noise Sources

2009 ◽  
Vol 28 (4) ◽  
pp. 237-244 ◽  
Author(s):  
Hugo E. Camargo ◽  
Patricio A. Ravetta ◽  
Ricardo A. Burdisso ◽  
Adam K. Smith
Keyword(s):  
Phased Array ◽  
Low Frequency ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Noise Sources ◽  
Array Technology

scholarly journals Methods for implementing the Kuznyechik algorithm on FPGAs

2018 ◽  
Vol 28 (3) ◽  
pp. 64-70
Author(s):  
I. I. Kalistru ◽  
M. A. Borodin ◽  
A. S. Rybkin ◽  
R. A. Gladko
Keyword(s):  
Data Processing ◽  
Linear Transformation ◽  
Data Transmission ◽  
High Speed ◽  
High Performance ◽  
Hardware Implementation ◽  
Block Cipher ◽  
Fpga Implementation ◽  
Is Implementation ◽  
The Cost

Increased volumes and speed of data transmission over computer networks, and also the need to protect the transmitted data, require accordingly to increase the speed of cryptographic data processing. One of the ways to achieve high performance is implementation of FPGAs-based cryptographic equipment. Therewith, to cut the cost of equipment, it is important that encryption modules shall consume a minimum possible hardware resources. The work aims to find the most compact high-speed solution for FPGA-based Kuznyechik block cipher. Several methods for hardware implementation of linear transformation, which is used in Kuznyechik cipher, have been reviewed. Various aspects of implementation of these methods taking into account the architecture of target FPGAs are investigated. We also consider aspects of the FPGA implementation of nonlinear transformation, which is used in Kuznyechik block cipher. Resource consumption by various implemented solutions of linear transformation has been estimated. A relatively compact high-speed implemented solution of Kuznyechik block cipher has been obtained and tested on the real equipment. The achieved values of speed for iterative and fully pipelined implementations of the algorithm have been presented.

Low-frequency radio recombination lines: observations and data processing

2017 ◽  
Vol 23 (1) ◽  
pp. 50-53
Author(s):  
A.A. Konovalenko ◽  
◽  
S.V. Stepkin ◽  
E.V. Vasilkovskiy ◽  
◽  
...  
Keyword(s):  
Data Processing ◽  
Low Frequency ◽  
Radio Recombination Lines

scholarly journals A Low frequency Southern Sky Survey Using the Mauritius Radio Telescope

2002 ◽  
Vol 199 ◽  
pp. 25-31
Author(s):  
N. Udaya Shankar
Keyword(s):  
Radio Telescope ◽  
Low Frequency ◽  
Fourier Synthesis ◽  
North East ◽  
The North ◽  
Sky Survey ◽  
Correlation Receiver ◽  
Complex Correlation ◽  
Right Ascension ◽  
East West

The Mauritius Radio Telescope (MRT) is a Fourier synthesis instrument which has been built to fill the gap in the availability of deep sky surveys at low radio frequencies in the southern hemisphere. It is situated in the north-east of Mauritius at a southern latitude of 20°.14 and an eastern longitude of 57°.73. The aim of the survey with the MRT is to contribute to the database of southern sky sources in the declination range −70° ≤ δ ≤ −10°, covering the entire 24 hours of right ascension, with a resolution of 4' × 4'.6sec(δ + 20.14°) and a point source sensitivity of 200 mJy (3σ level) at 151.5 MHz.MRT is a T-shaped non-coplanar array consisting of a 2048 m long East-West arm and a 880 m long South arm. In the East-West arm 1024 fixed helices are arranged in 32 groups and in the South arm 16 trolleys, with four helices on each, which move on a rail are used. A 512 channel, 2-bit 3-level complex correlation receiver is used to measure the visibility function. At least 60 days of observing are required for obtaining the visibilities up to the 880 m spacing. The calibrated visibilities are transformed taking care of the non-coplanarity of the array to produce an image of the area of the sky under observation.This paper will describe the telescope, the observations carried out so far, a few interesting aspects of imaging with this non-coplanar array and present results of a low resolution survey (13' × 18') covering roughly 12 hours of right ascension, and also present an image with a resolution of 4' × 4'.6sec(δ + 20.14°) made using the telescope.

scholarly journals Methodology for the Concept Design of Locally Reinforced Composites

2021 ◽  
Vol 11 (16) ◽  
pp. 7246
Author(s):  
Julius Moritz Berges ◽  
Georg Jacobs ◽  
Sebastian Stein ◽  
Jonathan Sprehe
Keyword(s):  
Cost Estimation ◽  
Structural Design ◽  
Early Stage ◽  
Parameter Study ◽  
Great Effort ◽  
Concept Design ◽  
Cost Weight ◽  
Reinforced Plastics ◽  
Fiber Reinforced Plastics ◽  
The Cost

Locally load-optimized fiber-based composites, the so-called tailored textiles (TT), offer the potential to reduce weight and cost compared to conventional fiber-reinforced plastics (FRP). However, the design of TT has a higher complexity compared to FRP. Current approaches, focusing on solving this complexity for multiple objectives (cost, weight, stiffness), require great effort and calculation time, which makes them unsuitable for serial applications. Therefore, in this paper, an approach for the efficient creation of simplified TT concept designs is presented. By combining simplified models for structural design and cost estimation, the most promising concepts, regarding the cost, weight, and stiffness of TT parts, can be identified. By performing a parameter study, the cost, weight, and stiffness optima of a sample part compared to a conventional FRP component can be determined. The cost and weight were reduced by 30% for the same stiffness. Applying this approach at an early stage of product development reduces the initial complexity of the subsequent detailed engineering design, e.g., by applying methods from the state of the art.

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