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Abstract The authors deal with the problem of the design and manufacture of a high‐resolution FMCW radar for drone detection and classification. The difficulties of the problem are discrete clutter reduction and spurious phase noise mitigation. The discrete clutter is due to the reflected signals from land vehicles, birds etc., while the spurious phase noise is inherent in the radar signal due to the phase‐locked loop component and leakage between the transmitting and receiving paths. Both spurious phase noise and clutter will increase the system noise level and hence reduce the probability of detection of small targets such as drones and induce false alarms on the radar screen. In order to reduce discrete clutter, the authors propose a method to separate a drone from discrete clutter based on the design of the radar system parameters for a drone and its propeller detection, target's Doppler dispersion and moving characteristics. For spur mitigation, a method that focuses on the design of the isolation coefficient between transmitting and receiving paths to decrease the power of spurs below the minimum power requirement at the input of the analogue‐to‐digital converter is introduced. The results were applied by the authors to the development and manufacture of a radar with the given specifications for drone detection and classification. Different laboratory and field tests show that the spurs are mitigated and the drones are separated from discrete clutter with a range and accuracy better than the one recently published.

By investigating Vietnamese English learners' perspectives on influential cultural factors and barriers these factors bring to the development of learner autonomy, this study seeks to draw attention to proper consideration of the host cultural values in importing and implementing Western educational theories. A phenomenological approach was employed, and qualitative data were collected from in-depth interviews with 15 English majored students from a public university in the Mekong Delta. Using Hofstede et al.'s (2010) six-dimensional model of cultural differences as a theoretical framework, the study reveals that all the six dimensions, at different levels, hinder the development of learner autonomy. The study also uncovers cultural assimilation - a state in which individuals perceive a certain cultural characteristic as their personality traits without any adjustment, corresponding to the Restraint factor. These results emphasize the significance of cultural analysis and imply the need for constructing a culturally appropriate pedagogy to promote learner autonomy. The paper concludes by discussing some possible directions for further research in the field.

This study examines the nonlinear dynamic response of sandwich plates placed on the Kerr elastic substrate under blast loading. The plate is composed of an auxetic honeycomb core and functionally graded material (FGM) coating layers. The volume fraction of FGM is determined following the power-law model (P-FGM). The equations of motion of the plate are formulated by using the first-order shear deformation theory (FSDT) in conjunction with the use of the Airy stress function. The Runge-Kutta scheme, with the assistance of the Galerkin technique, is utilized in the present study to obtain numerical results for the nonlinear dynamic response of the plate. After verifying the proposed solution, the influences of material characteristics, blast loading, elastic substrate, and geometry parameters on the free vibration and nonlinear dynamic behavior of the plate are investigated comprehensively. The results show that negative Poisson's ratio has a significant effect on the linear and nonlinear vibration characteristics of the auxetic-FGM sandwich plate. [ABSTRACT FROM AUTHOR]