In this study, a new current adaptive switching strategy with the spike limitation applied in DC/DC converter is proposed. With this switching strategy, the switching speed of the power switch can be regulated adaptively with the change of the load. The turn-on/turn-off current is inversely proportional to the load. So, at the light load, the switching speed of the power switch is faster and the switching losses are lower. In addition, all of the control should be based on one principle that the current/voltage spike across power switch under a smaller load cannot exceed that under a rated load. The switching characteristics of power switch with the proposed switching strategy and the relationship between current/voltage spike, turn-on/turn-off current and power loop stray inductance during the switching transition is discussed in this study. Moreover, the drive circuit is designed in detail. Finally, a boost converter prototype with 200 V _DC input voltage/380 V output voltage/1 kW output power is established to verify the proposed method. The tested results show that the efficiency of the converter adopted the proposed method rises by 1.5% comparing with that used a conventional switching strategy at the light load.

In recent years, brushless DC motors (BLDCMs) have replaced brushed DC motors in the design of electric scooters (ESs). This study proposes a new antilock braking system (ABS) based on a slip ratio estimator for ES utilising the braking force generated by the BLDCM when electrical energy is released to the virtual load, yielding an effect analogous to the ABS control in gas-powered vehicles. Compared with mechanical ABS, the proposed design possesses the advantage of rapid torque responses because no mechanical parts needed. Current control design is used to adjust the braking torque, and the sliding-mode control strategy is adopted to regulate the slip ratio to attain the optimal road adhesion during emergency braking. A variety of experiments are conducted for functional and performance verification.

An anti-jamming system based on Stackelberg game theory has been used in past to model the sequence of events of a jamming game in cognitive radio network. However, this approach fails to support the improvement of strategy in counteracting responsive and non-responsive attack. The proposed anti-jamming system selects a suitable strategy based on channel availability and jammer type. When channel availability is high, the interaction between cognitive radio and jammer is modelled using hidden Markov process, but when it is low, evolutionary game theory (EGT) is used. Furthermore, in the case of responsive jammer, a distraction strategy is incorporated to deceive the jammer, but Nash equilibrium is attained while dealing with mixed strategy of non-responsive jammer. The simulation results show that the proposed EGT-based anti-jamming system increases the throughput of system while decreasing the probability of bit error at least by 2% compared to the existing Stackelberg game approach.

Using a signal generator and an oscilloscope, measurements were made of the differential-mode current and the common-mode current in a twin-conductor cable installed on a test rig, over a range of frequencies which included half-wave resonances. Test data was used to assign component values to a Triple-T circuit model of the assembly. This model was then transformed into a transient coupling model. The signal generator was reset to generate square waves, and photographs were taken of the waveforms of the input voltage and the common-mode current. A close correlation was achieved between these waveforms and those of the transient coupling model. This demonstrates that the technique of circuit modelling and bench testing is reliable and accurate, in both the frequency domain and the time domain. The technique allows potential hazards due to transient interference to be analysed, tested, and quantified during the design process. Electromagnetic interference can be analysed without recourse to the mathematics of full-field modelling. It is also shown that, from the point of view of Electromagnetic Compatibility, the concepts of the single-point ground and the equipotential ground are both misleading and counter-productive.

In this study, two half-mode substrate integrated waveguide (HMSIW) filters are proposed by introducing wide U slot in the conventional SIW (substrate integrated waveguide) structure. In the first case, lower ISM (industrial, scientific and medical radio) band HMSIW filter is designed by extending the centre stub, thereby controlling the resonant frequency and bandwidth. In the second case, higher ISM band HMSIW filter is designed by shorting the extended stub using via. These filters are having a compact core size of 26 mm × 11 mm and work at 2.4 and, 5.8 GHz with a fractional bandwidth of 4.0 and 2.6%, respectively. The filter is fabricated with a single layer standard printed circuit board process. The measured results are good and in agreement with simulated results. The band-pass filter structure has the advantage of low insertion loss, good return loss, sharp side band rejection and compact size.

In this study, a systematic approach to the design and development of a high-efficiency, natural-air-cooled, single-phase inverter with a multilayer high-current printed-circuit board (PCB) magnetics is presented. The size and efficiency of inverters implemented with the silicon transistor technology have almost reached a certain limit. The use of wide bandgap power semiconductors, such as the silicon carbide metal–oxide–semiconductor field-effect transistor and the gallium nitride (GaN) enhancement-mode (e-mode) transistor not only pushes further the efficiency limits, but also shrinks the inverter size. A new approach is proposed here in order to obtain a high-efficiency inverter which relies basically upon the derivation of analytical expressions for the inverter losses as a function of the inverter modulation index, for the optimum transistor and highest switching frequency pair selection, and the design of the output filter based on a paralleled, multilayer PCB magnetics. In the developed 5 kVA single-phase full-bridge inverter, GaN e-mode transistors are used to minimise the inverter losses and to decrease the cooling requirement, and size of the system. The proposed systematic design approach has been verified on the implemented 5 kVA, 50 kHz, naturally-cooled GaN inverter, with a power density of 2.7 W/cm³ (44.3 W/inch³), and a full-load efficiency of 98%.

This study introduces an enhanced version of a previously published genetic algorithm based technique to allow fast and accurate detection of the vehicle plate number independently of the used application. Hence, significant enhancements are introduced to upgrade the genetic algorithm into a semi-hybrid category by preceding it with a sorting and subgrouping process that reduces the search space and following it by a rule-based local search to optimize its output. The updated population structure and its initiation with subsets of the sorted image foreground objects results in a linear relationship between the image complexity represented by the number of foreground objects and the genetic algorithm search space instead of being exponential in previous versions. Moreover, a novel extra variable-size-window adaptive binarisation step is introduced to overcome the problems of attached license symbols that cannot be solved by the skipping ability introduced in previous versions. Various image samples with a wide range in scale, orientation, and symbol connectivity have been experimented to verify the effects of the new improvements. Encouraging results with 99.2% detection accuracy have been reported using a public dataset outperforming the author of the dataset by more than 5.5% and the state of the art systems by 2%.

Financial time-series data have non-linear and uncertain behavior which changes across the time. Therefore, the need to solve non-linear, time-variant problems has been growing rapidly. Traditional models such as statistical and data mining approach unable to cope with these issues. The main objective of this study to combine forecasts from the autoregressive integrated moving average model, exponential (EXP) model, and the multi-layers perceptron (MLP) in a novel hybrid model. The analysis was based on financial data of Sudanese pound/EURO exchange rate in Sudan. In this case, simple additive combination and weight combination methods are used in combining linear and non-linear models to produce hybrid forecast. Comparison between benchmark models and hybrid indicates that the hybrid model offers more accurate forecasts with reduced mean-absolute percentage error of around 0.82% for all models over all forecasting horizons. Moreover, the results recommend that the non-linear method can be applicable to an alternate to linear combining methods to accomplish better forecasting accuracy. On the basis of the results of this study, the authors can conclude that further experiments to estimate the weight of the combination methods and more models essential to be surveyed so as to explore innovative concerns in series prediction.

The study on the coordination between vision and motion of children with developmental coordination disorder (DCD) can help understand the mechanism of DCD for timely and appropriate intervention. Whereas the existing visual-motor integrated systems rely on markers attached to the subject to track the eye gaze and body movements, which is too expensive and not suitable for DCD assessment. In this study, a markerless visual-motor tracking system which consists of an eye-tracker used to track the eye gaze and a Kinect used to capture the body movements is designed to monitor the behaviour of children in the fine motor tasks. Then the eye gaze position of the subject is matched into the motion image captured by Kinect. The current data of children placing pegs captured by the proposed system are analyzed quantitatively. We find that the visual movement speed of the children with DCD or at risk of DCD is slower than that of the typical developing children to focus on the target while their hand movement speed is almost the same. In addition to DCD analysis, the proposed system is meaningful to the monitoring of other diseases related to visual-motor coordination.

In this work, a complete model for the integration between the Photovoltaic Distributed Generation System (PV-DGS) and the utility grid is simulated by MATLAB/SIMULINK. The aims of this study are to provide active power of a given feeder and to improve the output power quality from the PV-DGS unit. To achieve these aims, Two PV-arrays with total power yield equal to 200 KW are modeled. The maximum power point tracking based on the perturb and observe technique is used to control the DC-DC converter. The voltage source converter is controlled to allow the system to operate in different modes. These modes are the unity output power factor and the reactive power compensation. Different control techniques have been applied including the conventional PI controller as well as the intelligent optimization tuning. A complete comparison between both techniques has been introduced and analyzed.