A novel prototype electrical impedance tomography (EIT) system, which uses single-ended signalling, is presented. The single-ended electrical impedance tomography system consists of a host computer, data acquisition system, switching box, MATLAB, and LabVIEW program. Ability of the system to detect and track hidden conductive and non-conductive objects was examined using a beaker (cylindrical shape) of 180 mm diameter and 280 mm height, filled with 3000 mL tap water, and with 16 electrodes attached. Stainless steel and Teflon rods with different sizes were placed in different locations inside the beaker, and images were obtained. All the objects were tested under multiple signal injection frequencies in the range of 12–1000 kHz. The results showed that the system could detect and track conductive and non-conductive objects during certain injection frequencies. The single-ended EIT system requires one wire connection to make one signal injection or measurement, and this is controlled using a multiplexer or switching box. Alternatively, an ordinary EIT system requires additional wire connections for single data measurement or injection, and a more complex circuit to control the I/O signals. This greater number of wires and increased circuit complexity will increase the data error rate and the cost significantly.

The aim of this research study is to find a new model of well rod pump which is less cost compare than previous models. The construction of well rod pump changed and this will lead to the use of low-energy consumption electrical motor at well rod pump drive unit. This is achieved by decreasing weight of drive unit by using composite materials. This is achieved by changing some parameters of drive unit: departure changeover interval from 3 to 6 m and maximum loading at the suspension point of rods 150 kN.

Human–computer interaction (HCI) has great potential for applications in many fields. The diversity of interaction habits and low recognition rate are main factors to limit its development. In this paper, a framework of multi-modality-based HCI is constructed. The interactive target can be determined by different modalities including gaze, hand pointing and speech in a non-contact and non-wearable way. The corresponding response is fed back timely to users in the form of audio–visual sense with an immersive experience. Besides, the decision matrix-based fusion strategy is proposed to improve the system's accuracy and adapt to different interaction habits which are considered in an ordinary hardware from a crowded scene without any hypothesis that the interactive user and his corresponding actions are known in advance. Experimental results have highlighted that the proposed method has better robustness and real-time performance in the actual scene by comparisons.

The leader-following consensus problem of the general fractional-order linear multi-agent systems via event-triggered control is considered. An effective event-trigger controller is designed, and then the leader-following consensus problem of the controlled multi-agent systems is studied by using the Lyapunov theory of fractional-order systems and linear matrix inequality method. The consensus condition and the convergence rate of the system are obtained based on the Mittag–Leffler stability of fractional-order systems. Simulation indicates the effectiveness of the theoretical results.

The authors present a comprehensive research tutorial on the ambiguity function (AF) of eigenwaveform for extended targets compared to AFs of common radar waveforms (e.g. wideband and pulsed waveforms). They present new findings of AF properties that contradict classical AF results for the point target assumption. It is shown that the AF properties (peak and volume) for an extended target are not constant thereby contradicting AF properties of waveforms for a point target. They investigate corresponding AFs and note many advantages (or few disadvantages) of using eigenwaveform compared to classical wideband and rectangular-pulsed waveforms. They investigate unambiguous range, range resolution, Doppler resolution, and detection probability of various waveforms for insightful engineering trade-offs. For illustration, they utilise two extended target models to show that these parameters are not only functions of the transmit waveform but also of the nature of the target. They use both single-pulse and pulse-train waveforms to produce AFs to illustrate the effect on Doppler and range ambiguities and resolutions. Finally, they investigate range-Doppler map (RDM) applications of the traditional waveforms and compared them with eigenwaveform RDM. They conclude that the eigenwaveform is superior in probability of detection and Doppler considerations compared to wideband and rectangular waveforms.

This study proposes a closed-loop fan drive system without using an encoder or current sensors. The cost and size of the fan drive system, therefore, are significantly reduced. By using low-resolution three-phase Hall-effect position sensors, three-phase sinusoidal pulse-width modulation voltages are generated to control a permanent magnet synchronous motor (PMSM) that a fan is connected to. Two methods, including the back-EMF estimation method and the impedance-phase estimation method, are proposed to determine the input voltage amplitude and phase of the PMSM. A digital signal processor, TMS 320F28335, is used to execute the control algorithms. The proposed impedance-phase estimation method is 25% more efficient than the back-EMF estimation method at low-speed operating range – below 1000 r/min. A detailed sensitivity analysis of the motor parameter variations is discussed. The implemented drive circuit, which is very compact, can be attached at the back of the PMSM and fan. Several experimental results are provided.

This study proposes a hybrid iterative learning (HIL) control scheme for single-phase uninterruptible power supply (UPS) inverters using inductor current active damping technique. A UPS inverter maintains a tightly regulated output voltage independent of loading conditions and disturbances. To achieve such performance, a fast transient recovery time with a minimum steady-state error is desired. Fast control techniques, such as proportional integral (PI), are not always known for good steady-state performance in single-phase applications. As the load voltage and current are periodic, therefore a hybrid control strategy has been proposed in which a PI controller is combined with an iterative learning controller to produce better transient and steady-state dynamics. Adoption of such a strategy enables the UPS inverter control to be realised with one voltage and one current sensor, respectively. System modelling, filter magnitude-frequency characteristics shaping and control design with stability analysis have been presented in this study. The designed HIL control strategy is examined through simulations in a MATLAB environment in the discrete time frame and experimentally verified for a single-phase UPS inverter system prototype using a Texas TMS320F2812 digital signal processor.

The study presents the thickness effect of mesh metal films printed onto glass substrate on the shielding effectiveness (SE) of such transparent screens. Currently, standards in microelectronic technology use a metal film thickness of between ∼100 nm and few micrometres, depending on the available deposition and implementation techniques. This study demonstrates that the thickness of mesh metal films is a key parameter which needs to be adjusted precisely. A theoretical model based on SE, complex impedance and optical transparency has been developed for this purpose. At microwaves, a relevant selection of the metal thickness values from 0.1 to 2 µm changes the SE at low frequency (from 36 to 40 dB at 2 GHz, respectively) while maintaining it constantly at a higher frequency (close to 20 dB at 18 GHz). The optical transparency of such mesh screens is kept constant over the entire visible light spectrum (78%). Experimental data are in complete agreement with the theoretical values.

In this study, a periodic structure as a passband filter for differential input signals is introduced that suppresses the common-mode noise with a high common-mode rejection ratio on a wide range of frequencies. The unit cell of the periodic structure consists of open-ended stubs under common-mode and short-ended stubs under differential-mode excitation. The proposed design procedure introduced in this paper can be exploited for different microwave frequency bands while the overall shape of the filter remains unchanged. To verify the design approach, the authors designed and fabricated a filter at the centre frequency of 7 GHz on a Rogers RO4003 substrate with a dielectric constant of 3.7 and a loss tangent of 0.0027. Their studies show that for a three-unit-cell structure with the overall size of 18 mm × 40 mm (0.75λ _g × 1.66λ _g), a differential fractional bandwidth of 8.6% and a rejection ratio over 55 dB are achieved while the differential in band insertion loss is around 2 dB.

In this study, incompressible and viscous external flow around a cylinder is simulated using the lattice Boltzmann method. The surface of cylinder is considered to be a rigid immersed body in the fluid flow. The fluid flow field is discretised by a uniform and fixed Cartesian mesh but there are difficulties in the modelling of curved boundaries. As a result, the cylinder surface is extrapolated by macroscopic properties at boundary nodes. On the other hand, to well treat with boundary condition of the cylinder surface and in the meantime, to save the computational effort, an innovation is applied in this research which solves this problem by introducing a new curved boundary condition to improve computational accuracy in lattice Boltzmann simulations. However, this method can be extended to other physical fields as well as fluid flow. The present results have been compared with the available numerical results which show good agreements.