This study proposes a general procedure to compute the load demand profile from a parking lot where a fleet of buses with electric propulsion mechanisms are charged. Such procedure is divided in three different stages, the first one models the daily energy utilisation of the batteries based on Monte Carlo simulations and route characteristics. The second one models the process in the charging station based on discrete event simulation of queues of buses served by a lot of available chargers. The third step computes the final demand profile in the parking lot because of the charging process based on the power consumption of batteries’ chargers and the utilisation of the available charges. The proposed procedure allows the computation of the number of required batteries’ chargers to be installed in a charging station placed at a parking lot in order to satisfy and ensure the operation of the fleet, the computation of the power demand profile and the peak load and the computation of the general characteristics of electrical infrastructure to supply the power to the station.

Aiming at the analog signal being converted into the digital with a higher precision, a method to improve the analog-to-digital converter (ADC) resolution is proposed and described. Based on the microcomputer PIC18F45K80 in which the internal ADC modules are embedded, a circuit is designed for doubling the resolution of ADC. According to the circuit diagram, the mathematical formula for calculating this resolution is derived. The corresponding software and print circuit board assembly is also prepared. With the experiment, a 13 bit ADC is achieved based on the 12 bit ADC module predesigned in the PIC18F45K80.

This study presents research that supplements and extends the previous works on design of space-time fully systematic unpunctured (FSU) serial concatenation of quadratic interleaved codes (SCQICs). The requirements for efficient design of the forward error correction (FEC) codecs motivated potential information-theoretic studies for enjoying the development of low-complex system components within the FEC encoder/decoder for securing the transmission reliability. Inspired by this motivation, this study not only provides design guidelines to achieve better bit error rate performance in terms of the major design factors of FSU-SCQICs, that is, component code constraint length and trellis structure, and FEC rate, but also estimates the gain gaps of different quadratic permutation (QP) structures in two crucial untouched aspects: (i) signal-to-noise ratio-region comparison on the optimality and (ii) investigation on the structural parameters of QPs, that is, cyclic shift and primitive factor.

The stop-and-go (SAG) model is typically used for echo signal received by the radar using linear frequency modulation pulse compression. In this study, the authors demonstrate that this model is not applicable to hypersonic targets. Instead of SAG model, they present a more realistic echo signal model (moving-in-pulse duration (MPD)) for hypersonic targets. Following that, they evaluate the performances of pulse compression under the SAG and MPD models by theoretical analysis and simulations. They found that the pulse compression gain has an increase of 3 dB by using the MPD model compared with the SAG model in typical cases.

Using of low-voltage variable-frequency drive followed by a step-up transformer is the most preferable way to feed an electrical submersible pump motor. The existence of long feeder between the motor and drive systems usually causes over-voltage problems because of the travelling wave phenomenon, which makes the employment of filter networks on the motor or inverter terminals mandatory. The so-called boost-inverter inherently can solve this problem with filter-less operation as it offers a direct sinusoidal output voltage. As boost inverters have voltage boosting capability, it can provide a transformer-less operation as well. This study investigates the performance of a five-phase modular winding induction machine fed from a boost-inverter through a long feeder. A simulation study using a 1000 Hp system and experimental investigation on a 1 Hp prototype machine are used to support the presented approach.

A new configuration of an ultra-wideband (UWB) dual band-notched antenna is presented. The designed geometry consists of octagonal radiating patch, a 50 Ω microstrip feed-line on the front and an asymmetric partial ground on the back. For impedance bandwidth enhancement, a unilateral stepped structure is utilised on the ground. By etching two E-shaped slots connected to each other on the radiating patch and applying E-shaped defected ground structure on the back, dual notched bands are achieved. The antenna is printed on a low profile FR4 substrate with a compact size of 25 × 18 × 1 mm³. The experimental results indicate that the antenna has an impedance bandwidth from 2.55 to 21.65 GHz for voltage standing wave ratio ≤2, except the notched bands on worldwide interoperability for microwave access and wireless local area network bands. Moreover, stable radiation patterns and gains within the operating band are shown.

This study presents a successive approximation register analog-to-digital converter with an energy-efficient switching scheme. A split-most significant bit capacitor array is used with a least significant bit-down switching scheme. Compared with the conventional binary-weighted capacitor array, it reduces the area and average switching energy by 50 and 87% under the same unit capacitor. Moreover, capacitor matching requirement is relaxed by 75%. A prototype design was fabricated in a 0.13 µm complementary metal oxide semiconductor process. It consumes 23.2 µW under 1 V analog supply and 0.5 V digital supply. Measured results show a peak signal-to-distortion-and-noise ratio of 55.2 dB and an effective resolution bandwidth up to 1.1 MHz when it operates at 1.1 MS/s. Its figure-of-merit is 44.1 fJ/conversion-step.

Wireless infrared communications can be defined as the propagation of light waves in free space using infrared radiation whose range is 400–700 nm. This range corresponds to frequencies of hundreds of terahertz, which is high for higher data rate applications. Wireless infrared is applied for higher data rates applications such as wireless computing, wireless video and wireless multimedia communication applications. Introduced by Gfeller, this field has grown with different link configurations, improved transmitter efficiency, increased receiver responsivity and various multiple access techniques for improved quality. Errors are caused because of background light, which causes degradation overall system performance. Error correction techniques are used to remove the errors caused during transmission. This study provides a brief account on field theory used for error correction in wireless infrared systems. The results are produced in terms of bit error rate and signal-to-noise ratio for various bit lengths to show the ability of encoding and decoding algorithms.

Orthogonal variable spreading factor codes are used in the downlink to maintain the orthogonality between different channels and are used to handle new calls arriving in the system. A period of operation leads to fragmentation of vacant codes. This leads to code blocking problem. The assignment scheme proposed in this paper is not affected by fragmentation, as the fragmentation is generated by the scheme itself. In this scheme, the code tree is divided into groups whose capacity is fixed and numbers of members (codes) are variable. A group with maximum number of busy members is used for assignment, this leads to fragmentation of busy groups around code tree and compactness within group. The proposed scheme is well evaluated and compared with other schemes using parameters like code blocking probability and call establishment delay. Through simulations it has been demonstrated that the proposed scheme not only adequately reduces code blocking probability, but also requires significantly less time before assignment to locate a vacant code for assignment, which makes it suitable for the real-time calls.

In view of the present situation of the Afghanistan electricity sector, the photovoltaic and diesel generator stand-alone hybrid power system is increasingly attractive for application in rural and remote communities. Thousands of rural communities in Afghanistan depend solely on traditional kerosene for illumination and rarely have access to electricity sources such as DC battery for radio and other small appliances. This study is conducted to offer real-life solution to this problem. The hybrid system is investigated to meet the domestic load demand that is estimated based on the communities’ electricity consumption culture. At first, customary pre-design is pursued. Afterwards, the break-even point and net present value algorithms are applied for economic analysis. That makes this study differ from the previous academic literature. The concepts developed in this study are targeted for a cost-effective hybrid system, which is appropriate for rural and remote residents’ lifestyle change and improvement. Based on the academic research methods, overall analysis procedures can fit as an analogy, especially for developing countries.

In this study, the authors consider the problem of spectrum sensing based on energy detection method in cognitive radio over wireless communication channels when users experience fading and non-fading effects. The closed-form analytical expressions for the detection probability are derived over non-fading additive white Gaussian noise channel and Rayleigh and log-normal shadowing fading channels. The detection probability involves Marcum-Q function, summations and integrations in the early research papers, which are replaced by closed-form expressions in this study. The probability distribution function of fading channels is used to obtain the expressions for detection probability. The new derived numerical results are simulated under various parameters. The performance of the derived theoretical expressions closely matches with the simulated results.

In this Letter, an improved method for estimating the time delay in preamble-aided orthogonal frequency division multiplexing systems is presented. It uses a conventional preamble structure and combines cross-correlation techniques to achieve estimations of time delay and the number of multipaths without any additional overhead. Computer simulations results show that the proposed method is of near-ideal property in frequency-selected channels.

Accurate measurement of residual stress in metallic components using the contour method relies on the achievement of a good quality cut, on the appropriate measurement of the deformed cut surface and on the robust analysis of the measured data. There is currently no published standard or code of practice for the contour method. As a first step towards such a standard, this study draws on research investigations addressing the three main steps in the method: how best to cut the specimens; how to measure the deformation contour of the cut surface; and how to analyse the data. Good practice guidance is provided throughout the text accompanied by more detailed observations and advice tabulated in Appendix.

Fast Fourier transform (FFT) and inverse FFT (IFFT) are the fundamental algorithms at the heart of optical orthogonal frequency division multiplexing (OOFDM) transceivers. The high digital signal processing (DSP) complexity has become one of the most significant obstacles to experimentally demonstrating real-time high-capacity OOFDM transceivers. In this study, extensive numerical explorations are undertaken, for the first time, of the impacts of each individual transceiver DSP element on the inverse error vector magnitude (IEVM) performance of the OOFDM transceivers incorporating full-parallel pipelined FFT/IFFT architectures. More importantly, FFT/IFFT stage-dependent minimum bit resolution maps are identified, based on which minimum bit resolutions of individual DSP elements of various FFT/IFFT stages can be easily selected according to chosen analogue-to-digital converter/digital-to-analogue converter resolutions. The validity and high accuracy of the identified maps are experimentally verified in field programmable gate array (FPGA)-based platforms. In addition to great ease of practical OOFDM transceiver designs, the maps also significantly reduce the FPGA logic resource usage without degrading the overall transceiver IEVM performance.

This study addresses a micro-grid electricity market (MGEM) with day-ahead (DA) and real-time market mechanisms integrated. The bidding mechanisms for the market are described in this study, considering the generation cost of different distributed energy resources (DERs), like distributed generator, energy storage system and demand response. Including load and renewable generation forecasting systems and a fuzzy decision supporting system, a hierarchical micro-grid energy management system (MG-EMS) is then proposed to ensure the benefits of involved micro-grid central controller, DER owners and customers. To verify the feasibility of the proposed system, the whole-year historical pricing and load data for New England independent system operator are employed. The numerical results show that the proposed MG-EMS is promising and effective for the operations of MGEM.

It was proposed in the former research that chaos control can be used to suppress electromagnetic interference (EMI) in DC–DC converters. Analysis on a half-bridge converter is detailed in this study. Here, the practical example of the power supply of personal computers is given to show that, with an external chaotic signal to a pulse width modulation control circuit, the proposed approach can reduce EMI by reducing the amplitudes of power signals such as transformer current and output inductor currents at multiples of fundamental frequency.

In this study, a 65 nm complementary metal oxide semiconductor (CMOS) broadband self-calibrated high-sensitivity power detector for use in the Square Kilometre Array (SKA), the next-generation high-sensitivity radio telescope, is presented. The power detector calibration is performed by adjusting voltages at the bulk terminals of the input transistors to compensate for mismatches in the output voltages because of process, voltage and temperature variations. Measurements show that the power detector, preceded by an input power-match circuit with 6 dB gain, has an input signal range from −48 to −11 dBm over which a 0.95 dB maximum error in the detected power is observed when the calibration rate is 20 kHz. The proposed broadband power detector has a 3 dB upper band edge of 1.8 GHz, which adequately covers the midband SKA frequency range from 0.7 to 1.4 GHz. The settling time and the calibration time are both <5 μs. The circuit consumes 1.2 mW from a 1.2 V power supply and the input-match circuit consumes another 5.8 mW. The presented power detector achieves the best combination of the detection range and sensitivity of previously published circuits.