Recognition of jet engines via sparse decomposition of ISAR images using a waveguide scattering model

2017 ◽  
Vol 9 (6) ◽  
pp. 1339-1343 ◽  
Author(s):  
Simon Wagner ◽  
Joachim Ender
Keyword(s):  
Electromagnetic Waves ◽  
Radar System ◽  
Synthetic Aperture ◽  
Jet Engines ◽  
Signal Model ◽  
Common Assumption ◽  
Sparse Decomposition ◽  
Imaging Radar ◽  
Scattering Centers ◽  
The Common

Air target recognition is a critical step in the radar processing chain and reliable features are necessary to make a decision. The number and position of jet engines are useful features to perform a pre-classification and give a list of possible targets. To extract these features, a sparse decomposition framework for inverse synthetic aperture radar (ISAR) images is presented. With this framework different components of the target can be detected, if signal models for these parts are available. To use it for the detection of jet engines, a review of a signal model for air intakes, which was developed by Borden, is given. This model is based on the common assumption that the propagation of electromagnetic waves inside jet engines has the same dispersive behavior as inside waveguides. With this model a decomposition of a real ISAR image, measured with the tracking and imaging radar system of Fraunhofer FHR, into point-like scattering centers and jet engines is presented.

A terahertz photonic imaging radar system based on inverse synthetic aperture technique

2021 ◽  
Author(s):  
Shiwei Wang ◽  
Zijie Lu ◽  
Hongqi Zhang ◽  
Lu Zhang ◽  
Mengyao Qiao ◽  
...  
Keyword(s):  
Radar System ◽  
Synthetic Aperture ◽  
Imaging Radar

scholarly journals Radar and UAV: georeferencing and airspace surveillance system

2018 ◽  
Vol 11 (2) ◽  
pp. 190-199
Author(s):  
Jonnathan Navarro Roa ◽  
Félix Parca Acevedo ◽  
Giovani Mancilla Gaona
Keyword(s):  
Surveillance System ◽  
Electromagnetic Waves ◽  
Radar System ◽  
Synthetic Aperture ◽  
Electromagnetic Signal ◽  
Radio Detection ◽  
Aerial Vehicle ◽  
The Doppler Effect ◽  
The Waves ◽  
Support Research

A ¨RADAR¨ system, from the English Acronym ¨Radio Detention and Ranging¨. Better known as ¨Radio Detection and Location¨ RDL.  It is a system for detecting and positioning objects through shipping and reflection of electromagnetic waves in terms of the time of issue and the return of the waves and their speed (calculated by the Doppler effect of the electromagnetic signal received).  Meanwhile, an autonomous unmanned vehicle, also known as Unmanned Aerial Vehicle, UAV, which is defined as an aircraft which does not carry a human operator, and uses aerodynamic forces to provide airlift by itself. Therefore, it can fly autonomously or it can be operated by remote control.  This article focuses on the review of experiences where these two technologies are integrated, particularly UAVSAR (Uninhabited Aerial Vehicle Synthetic Aperture Radar). This is done in order to support research concerning the combination thereof to be applied in georeferencing humanitarian missions or military missions that require monitoring of airspace. 

Student Perceptions of Community: A Different Perspective

NASPA Journal ◽  
1998 ◽  
Vol 35 (4) ◽  
Author(s):  
Jackie Clark ◽  
Joan Hirt
Keyword(s):  
Student Perceptions ◽  
Large Scale ◽  
Research University ◽  
Small Scale ◽  
Social Environments ◽  
Common Assumption ◽  
Small Communities ◽  
Public Research University ◽  
The Common ◽  
Using Data

The creation of small communities has been proposed as a way of enhancing the educational experience of students at large institutions. Using data from a survey of students living in large and small residences at a public research university, this study does not support the common assumption that small-scale social environments are more conducive to positive community life than large-scale social environments.

A high resolution medium penetrating imaging radar system

2015 ◽  
Author(s):  
Ren Xiao-yuan Ren Xiao-yuan ◽  
Liu Hai-bo Liu Hai-bo ◽  
Li Jin-bing Li Jin-bing
Keyword(s):  
High Resolution ◽  
Radar System ◽  
Imaging Radar

scholarly journals Śaivism after the Śaiva Age: Continuities in the Scriptural Corpus of the Vīramāheśvaras

Religions ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 222
Author(s):  
Elaine M. Fisher
Keyword(s):  
Thirteenth Century ◽  
Common Assumption ◽  
Academic Practice ◽  
The Common ◽  
Popular Work ◽  
First Time

This article makes the case that Vīraśaivism emerged in direct textual continuity with the tantric traditions of the Śaiva Age. In academic practice up through the present day, the study of Śaivism, through Sanskrit sources, and bhakti Hinduism, through the vernacular, are generally treated as distinct disciplines and objects of study. As a result, Vīraśaivism has yet to be systematically approached through a philological analysis of its precursors from earlier Śaiva traditions. With this aim in mind, I begin by documenting for the first time that a thirteenth-century Sanskrit work of what I have called the Vīramāheśvara textual corpus, the Somanāthabhāṣya or Vīramāheśvarācārasāroddhārabhāṣya, was most likely authored by Pālkurikĕ Somanātha, best known for his vernacular Telugu Vīraśaiva literature. Second, I outline the indebtedness of the early Sanskrit and Telugu Vīramāheśvara corpus to a popular work of early lay Śaivism, the Śivadharmaśāstra, with particular attention to the concepts of the jaṅgama and the iṣṭaliṅga. That the Vīramāheśvaras borrowed many of their formative concepts and practices directly from the Śivadharmaśāstra and other works of the Śaiva Age, I argue, belies the common assumption that Vīraśaivism originated as a social and religious revolution.

scholarly journals Adverse Selection, Heterogeneous Beliefs, and Evolutionary Learning

2021 ◽  
Author(s):  
Clemens Buchen ◽  
Alberto Palermo
Keyword(s):  
Adverse Selection ◽  
Relative Size ◽  
Nonlinear Dynamic System ◽  
Heterogeneous Beliefs ◽  
Evolutionary Learning ◽  
Common Assumption ◽  
Cobweb Model ◽  
The Common ◽  
Learning Set ◽  
Set Up

AbstractWe relax the common assumption of homogeneous beliefs in principal-agent relationships with adverse selection. Principals are competitors in the product market and write contracts also on the base of an expected aggregate. The model is a version of a cobweb model. In an evolutionary learning set-up, which is imitative, principals can have different beliefs about the distribution of agents’ types in the population. The resulting nonlinear dynamic system is studied. Convergence to a uniform belief depends on the relative size of the bias in beliefs.

Reform, corruption, and growth: Why corruption is more devastating in Russia than in China

2006 ◽  
Vol 39 (2) ◽  
pp. 265-281 ◽  
Author(s):  
Tomas Larsson
Keyword(s):  
Economic Growth ◽  
Comparative Advantage ◽  
Economic Performance ◽  
Political Corruption ◽  
Common Assumption ◽  
Rapid Economic Growth ◽  
The Common ◽  
The Impact ◽  
Intervening Factors

This article explains why massive political corruption appears to be incompatible with economic growth in Russia but compatible with very rapid economic growth in China. The common assumption is that corruption is bad for economic performance. So how can we explain the puzzling contrast between Russia and China? Is Russia being more severely “punished” for its corruption than China? If so, why? This article demonstrates that three intervening factors—comparative advantage, the organization of corruption, and the nature of rents—determines the impact of corruption on economic performance, and that these factors can explain the divergent outcomes. The article thereby offers an alternative to statist explanations of the Russia-China paradox.

Utilization of heterologous siderophores and rhizosphere competence of fluorescent Pseudomonas spp.

1995 ◽  
Vol 41 (2) ◽  
pp. 126-135 ◽  
Author(s):  
Jos M. Raaijmakers ◽  
Lentse van der Sluis ◽  
Peter A. H. M. Bakker ◽  
Bob Schippers ◽  
Margot Koster ◽  
...  
Keyword(s):  
Wild Type Strain ◽  
Population Densities ◽  
Common Assumption ◽  
Fluorescent Pseudomonas ◽  
Siderophore Receptors ◽  
Rhizosphere Interactions ◽  
Rhizosphere Population ◽  
Rhizosphere Competence ◽  
The Common ◽  
Derivative Strain

In this study, the potential of different Pseudomonas strains to utilize heterologous siderophores was compared with their competitiveness in the rhizosphere of radish. This issue was investigated in interactions between Pseudomonas putida WCS358 and Pseudomonas fluoresceins WCS374 and in interactions between strain WCS358 and eight indigenous Pseudomonas strains capable of utilizing pseudobactin 358. During four successive plant growth cycles of radish, strain WCS358 significantly reduced rhizosphere population densities of the wild-type strain WCS374 by up to 30 times, whereas derivative strain WCS374(pMR), harboring the siderophore receptor PupA for ferric pseudobactin 358, maintained its population density. Studies involving interactions between strain WCS358 and eight different indigenous Pseudomonas strains demonstrated that despite the ability of these indigenous isolates to utilize pseudobactin 358, their rhizosphere population densities were significantly reduced by strain WCS358 by up to 20 times. Moreover, rhizosphere colonization by WCS358 was not affected by any of these indigenous strains, even though siderophore-mediated growth inhibition of WCS358 by a majority of these strains was demonstrated in a plate bioassay. In conclusion, it can be stated that siderophore-mediated competition for iron is a major determinant in interactions between WCS358 and WCS374 in the rhizosphere. Moreover, our findings support the common assumption that cloning of siderophore receptor genes from one Pseudomonas strain into another can confer a competitive advantage in interactions in the rhizosphere. Interactions between WCS358 and the selected indigenous rhizosphere isolates, however, indicate that other traits also contribute to the rhizosphere competence of fluorescent Pseudomonas spp.Key words: siderophore, siderophore receptors, root colonization, fluorescent Pseudomonas.

Artificially Ventilated Cavities: Evaluating the Constant-Pressure Approximation

2017 ◽  
Author(s):  
Melissa A. Fronzeo ◽  
Michael Kinzel ◽  
Jules Lindau
Keyword(s):  
Constant Pressure ◽  
Flow Behavior ◽  
Internal Cavity ◽  
Common Assumption ◽  
Ventilated Cavity ◽  
Physical Insight ◽  
Circulatory Flow ◽  
Computational Fluid Dynamics Cfd ◽  
The Common ◽  
Semi Empirical

Computational Fluid Dynamics (CFD) is employed to study the fundamental aspects of the internal pressure within artificially ventilated, gaseous cavities in both twin- and toroidal-vortex closure modes. The results show that several pressure regions develop within the cavities, indicating that the common assumption that the cavity has a constant pressure breaks down when evaluated in high detail. The internal cavity pressure is evaluated using a probability density function (PDF). The resulting PDF plots show a clusters with multiple peaks. A mixture-of-Gaussians (MOG) method is employed to better understand the distributions of these peaks. These peaks are then mapped to the simulation results, where it is observed that these peaks correlate to distinct cavity regions (which vary depending on cavity type). Moreover, these varying pressure regions appear to align with cavity-radius growth and reduction and appear to be the driving force of the internal, circulatory flow. Lastly, the importance of these pressure regions are investigated with respect to predictions from semi-empirical theory of the cavity shape, showing a moderate impact depending on where the cavity is probed. Overall, these results provide physical insight into ventilated cavity flow behavior that is often ignored.

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