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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.

We evaluated an absorbance effectiveness on the solar spectrum using an absorption figure of merit (a-FOM) for the conducting thin films. In particular, Ni-doped and un-doped CuO thin films were deposited by a facile and sustainable solution-processed synthesis, whose Ni doping concentration was varied to be 0.2, 0.6, 1, 2, 3, 4 wt%. We observed a change of smooth surface to an appearance of nanoparticles by Ni doping, which supported to form of a plasmonic mechanism for improving the light capture and retention. The absorption of long wavelengths was improved and extended to the near-infrared range. That is, the bandgap energy decreased from 2.10 to 1.88 eV with Ni doping. Also, we found that the absorption length decreased from 99.93 nm to 63.80 nm as the Ni doping increased. In addition, the CuO-based film with 4 wt% Ni doping showed a maximal value of a-FOM as high as 30.88 Ω−1cm−1, corresponding to a resistance of 2.07 MΩ/sq and an absorption length of 63.80 nm. Our finding suggested that Ni-doped CuO thin films can be considered as an excellent selection of absorbent conductive oxide layers for application in optoelectronic devices and solar cell systems.

Purpose – The purpose of this study is to analyze the influence of the emotional experience (EE) and the image of the tourist destination on the satisfaction of the domestic tourist and his behavioral intentions, represented through the word of mouth (WOM) and his revisit intention. Design/methodology/approach – The information obtained through a personal survey to 382 local tourists was refined and subjected to structural equation analysis. Analyses conducted with SPSS 20.0 and AMOS 20 software confirmed the existence of interesting significant relationships. Findings – The results show that positive destination image and different experiences are considered to be the main elements that promote positive emotions and satisfaction for tourists, leading to a higher eagerness to spread WOM recommendations and to revisit a destination. The results also verify that interactions with the difficult-replacement services and with residents create strong positive EEs for female visitors, so that they are more willing to revisit a destination than males. Research limitations/implications – Eco-destination managers should provide more difficult-replacement services and create an enjoyable and unique experience for tourists to enhance their satisfaction and positive behavioral intentions. Originality/value – The results provide some important implications and insights about the marketing theory groundwork of EE and satisfaction, such as how they are to be conceptualized and established and how interactive relationships are formed among them in the ecotourism context.

This collection of 10 articles is from the conference "The Anthropology of Language in Mainland Southeast Asia", held August 19 and 20, 2019 at the University of Sydney.

This paper gives an overview of the phonetic characteristics of the tone system of the Cuoi language, a Vietic language spoken in Nghe An province in Vietnam.

In this paper, we consider second order differential inclusions with periodic boundary conditions. We obtain the existence of positive solutions and of continuous branches of positive solutions.

Abstract In this paper, free vibration analysis of rotating functionally graded cylindrical shells with orthogonal stiffeners is presented. Based on Love's first approximation theory and smeared stiffeners technique, the governing equations of motion which take into account the effects of initial hoop tension and also the centrifugal and Coriolis forces due to rotation are derived. The influence of the power law index, the stiffener's height-to-width ratio, the circumferential wave numbers, the shell length-to-radius ratio, and the shell radius-to-thickness ratio on the natural frequencies of the simply supported rotating stiffened functionally graded cylindrical shell are investigated. To validate the present analysis, comparisons are made with those available in the literature for particular cases; very good agreements are achieved.

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]

Cupric-oxide-based thin films with various amounts of 0, 1, 2, 3, and 4 wt.% Ni doping were, in turn, deposited on ITO/glass substrates via a solution process. The 0.25 M concentrated solutions of copper (II) acetate monohydrate and nickel acetate tetrahydrate were used as starting materials mixed in ethanol solvent, in order to form the precursors. We obtained that the crystalline structure was not affected by the increase in Ni doping concentration as evidenced by X-ray diffraction patterns. The surface morphology observed by scanning electron microscope pointed out the presence of linked-structure nanoparticles. The influence of Ni doping on the optical bandgap width was evaluated by using ultravioletvisible spectrometry. We found that the optical bandgap should be direct, and it decreased from 2.69 to 2.38 eV for the range doped. Interestingly, we determined the relaxation time of the Ni-doped CuO/ITO/glass structure from measuring the electrochemical impedance spectroscopy, and it was 0.36 s for the undoped film, then gradually decreased to be 0.31, 0.11, 0.1, and 0.04 s with increasing the Ni doping concentration. This achievement result will serve as a foundation for the future photonic researches. [ABSTRACT FROM AUTHOR]

This study offers a unique solution for the free vibration of rotating FGP sandwich cylindrical shells under different boundary conditions. A new type of sandwich structures with a metal-foam core and two coating FGM layers is investigated. Equations of motion governing the free vibration of rotating shells are derived by the first-order, shear-deformation shell theory. Single-term modal functions are introduced in Rayleigh-Ritz method to efficiently determine natural frequencies of the shell. After result validations, the influence of volume fraction index, distribution schemes, core-layer thickness, porosity coefficient, rotating velocity, geometrical parameters, and boundary conditions on the shell natural frequencies are studied. [ABSTRACT FROM AUTHOR]