Active calibration target for bistatic radar cross-section measurements

Either passive calibration targets are expensive and complex to manufacture or their bistatic RCS levels are significantly lower than the monostatic RCS levels of targets such as spheres, dihedral- and trihedral corner reflectors. In this paper the performance of an active calibration target with relative high bistatic RCS values is illustrated as a reference target for bistatic RCS measurements. The reference target is simple to manufacture, operates over a wide frequency range and can be configured to calibrate all four polarizations (VV, HH, HV and VH). Bistatic RCS measurements of canonical targets, performed in a controlled environment, are calibrated with the reference target and the results are compared to simulated results using FEKO.http://agupubs.onlinelibrary.wiley.com/agu/journal/10.1002/(ISSN)1944-799X2016-11-30hb2016Electrical, Electronic and Computer Engineerin

An active wideband reference target for the calibration of ground to air radar systems

The radar cross section (RCS) of passive calibration targets is relatively low, which leads to a commensurate increase in the uncertainty of the radar’s calibration. To address this deficiency, an active radar calibration (ARC) target was developed, which was mounted on a small remote controlled tri-copter and used for radar calibration. Results are presented for this relatively small, light weight and cost effective airborne ARC, which is suitable for the calibration of a ground to air RCS measurement system. The static RCS characteristics of the airborne ARC target were measured in a compact range and compared to outdoor measurements with the ARC target mounted on the tri-copter. The airborne capability of the calibration target was used to reduce the effects of multi-path and clutter.http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1098-27602017-05-31hb2016Electrical, Electronic and Computer Engineerin

A conceptual framework for understanding leader selfschemas and the influence of those self-schemas on the integration of feedback

Orientation: Recently, the importance of blind spots, derailments and failures of leaders have been in the spotlight. Enhancing their levels of self-awareness is one of the steps leaders can take to avoid derailment. While it promotes self-awareness and decreases leadership blind spots, feedback is also considered one of the most effective tools available to modify behaviour. Researchers and practitioners are encouraged to explore the individual characteristics that will enhance or impede the feedback received from others so as to bring about behavioural change and increased levels of self-awareness. Motivation for the study: The aim of this theoretical article was to consider various conceptual frameworks and literature in an endeavour to illustrate how leaders’ self-schemas might explain the underlying reasons why some leaders are more likely to receive, integrate, assimilate and act on the feedback, while others are not, based on how they see themselves in relation to others. Research design, approach and method: A literature-based method was utilised for this study in order to provide a critical analysis of the available literature and illustrate the different theoretical perspectives and underpinnings. Practical/managerial implications: Leaders who are more likely to consider feedback and/or ask for feedback from others seem to be less prone to develop a blind spot and will therefore have a more accurate view of themselves. Those who have an over-rating of themselves are unlikely to have an accurate view of themselves. In an attempt to ‘protect’ this inflated view, such individuals will be less open to negative feedback, as it may challenge their own perspectives and opinions they hold of themselves. Individuals who hold an overly negative view of themselves are more likely to reject positive feedback and less likely to request or accept positive feedback as it may contradict the viewpoint they hold of themselves. They may however be more open to negative feedback that may ‘support’ their negative view of themselves. Contribution: This article provided some suggestions as to why leaders may be less willing to accept and integrate feedback into their self-schemas as well as how to develop their levels of self-awareness in order to benefit from feedback

Efeito do espaçamento e da idade sobre variáveis de povoamentos de Pinus Taeda L. Effect of spacing and age on stand variables of Pinus Taeda L.

O objetivo deste estudo foi analisar os dados de um experimento sobre espaçamento inicial, implantado em povoamentos de Pinus taeda L. não-desbastados pertencentes à empresa IGARAS, localizados no Planalto Serrano do Estado de Santa Catarina, no Sul do Brasil. O experimento consistiu em um delineamento em blocos casualizados com três repetições e nove tratamentos (espaçamentos 1,5 x 1,0; 2,0 x 1,0; 2,5 x 1,0; 1,5 x 2,0; 2,0 x 2,0; 1,5 x 3,0; 2,5 x 2,0; 2,0 x 3,0; e 2,5 x 3,0 m). As medições foram realizadas nas idades de 4 a 14 anos. O efeito dos espaçamentos e da idade sobre as variáveis do povoamento foi analisado por meio do teste de Scott-Knot e de análise de regressão. Os resultados apontaram que os espaçamentos influenciam a tendência de crescimento em altura total, em área basal por ha, em diâmetro quadrático, em volume por árvore e em volume por ha. Os resultados permitiram confirmar que o espaçamento possui pouco efeito sobre as estimativas de altura total e que, aos 14 anos, os maiores espaçamentos proporcionam maiores estimativas de diâmetro quadrático, de volume por árvore e de sobrevivência e menores estimativas de área basal por ha e de volume por ha.<br>The objective of this study was to analyze data from an experiment on initial spacing, installed in unthinned stands of Pinus taeda L. owned by IGARAS company, located in the Planalto Serrano, State of Santa Catarina, in Southern Brazil. The experiment was arranged in a randomized block design with three repetitions and nine treatments (spacing 1.5 x 1.0; 2.0 x 1.0; 2.5 x 1.0; 1.5 x 2.0; 2.0 x 2.0; 1.5 x 3.0; 2.5 x 2.0; 2.0 x 3.0; and 2.5 x 3.0 m). The measurements were taken from 4 to 14 years. The spacing and age effect on stand variables was analyzed by the Scott-Knot test and regression analysis. The results showed that the spacing influenced the growth tendency for total height, basal area per ha, quadratic mean diameter, volume per tree and volume per ha. The results allowed the confirmation that the spacing has little effect on the estimates of total height, and up to 14 years, the largest spacings provide larger estimates for quadratic mean diameter, volume per tree and survival, and smaller estimates for basal area per ha and volume per ha