The present study compared whole body volumes obtained by three-dimensional (3D) photonic scanning of two different poses and discussed its effect on body composition estimation. Pose A with large angles of shoulder abduction and feet separated and Pose B with shoulders abducted slightly, the elbows extended and heels together. 16 male and 13 female participants were scanned twice in each pose using a 3D scanner. The mean of whole body volume and the mean of body composition obtained with Pose B was corrected by a regression equation and compared with the results obtained from Pose A. After correction, the whole body volumes acquired with these two poses were similar [limit of agreement = (−0.71 l,0.71 l)] but the body compositions obtained with Pose A and Pose B were different [limit of agreement = (−4.4%, 4.4%)]. The results indicated that scanning using either pose gives reliable estimations for whole body volume and body composition. The whole body volume obtained from different poses can be adjusted using the regression equation but small volumetric differences translate into much more substantial differences in body fat percentage. Hence, it is recommended to use the same scanning pose consistently when monitoring individuals longitudinally.

In this study, the positive inception voltage of bare and dielectric-coated stranded conductors has been researched by numerical calculations and corona cage experiments. The charge simulation method is used to calculate the potential gradient distribution of the coated stranded conductors. Then, based on the positive inception criterion, the photoionisation inception model considering the effective radiation wavelength is proposed and employed to evaluate the inception voltage of the coated stranded conductors. In addition, in the laboratory, the inception voltage test platform is build up to measure the inception voltage. The results reveal that with the increase of the coating layer thickness, the inception voltage increases. For the same thickness, the inception voltage reduces slightly with the increase of relative permittivity. The calculated values are in good agreement with experimental results of the laboratory corona cage. The conclusion lays a foundation for studying the effect of the coating layer on the corona performance.

As the reference detector of absolute radiance calibration primary radiometer (ARCPR) for space remote sensing, total solar irradiance (TSI) cavity is investigated to ensure the measurement accuracy. TSI cavity adopts a sloping bottom cavity. The geometrical parameters and paint material of sloping bottom cavity are both optimised to improve the invariance of absorptance in the environment of ground and space. The optimisation of substitution method is proposed to measure the average absorptance by two-dimensional scan. The uniformity is evaluated by absorptance map. Experimental results illustrate that sloping bottom cavity has a super-high absorptance of 0.999928 (wavelength is 632 nm), and the relative measure uncertainty is approximated to 6 ppm. Meanwhile, compared with the absorptance map of conical cavity, the sloping bottom design improves the uniformity of absorptance. Therefore, the sloping bottom cavity can be adopted as the reference detector of ARCPR. Furthermore, the optimised substitution method is suitable for the investigation of the blackbody cavity with super-high absorptance.

A novel method to experimentally determine the dynamic response of MEMS thermal actuators based on blurred still images of motion is presented. The apex displacement of thermal actuators proves to be a first-order linear system, whose dynamic response is depended on the system coefficient. In the frequency domain, the system coefficient of actuators excited by sinusoidal wave can be obtained from the fitted curve of vibration amplitude against frequency. An improved wavelet transform detection algorithm is proposed to acquire the vibration amplitude from blurred images taken by an ordinary camera. Compared with the conventional optical measurement method, the proposed method uses only still images instead of complex laser and optical reflecting systems, which has great potential for wide application. For the actuator in this study, the measured response time by blurred images and high-speed camera method are 14.87 and 15.25 ms with a deviation of 2.5%, which indicates the proposed method can obtain sufficient accurate results without sophisticated equipment and high cost.

Conveyor belt longitudinal tear is one of the most serious problems in coal mining. It is very important to detect it in real-time before the length of the tear is too long. In this study, a method of longitudinal tear detection based on visible light charge coupled device (CCD) and infrared CCD is proposed. A visible light and infrared vision real-time detection system for conveyor belt longitudinal tear is designed based on this method. In this method, the infrared CCD uses adaptive histogram equalisation coordinating with Hough transform line detection. The visible light CCD, coordinating with a laser line source, uses the Hough transform algorithm and the features from accelerated segment test algorithm. These two kinds of CCDs work together to make detection results reliable. Experimental results show that the proposed method is effective and adaptive, and meets the requirements for reliable, real-time and online longitudinal tear detection. Compared to several current methods, the proposed method has a better performance on efficiency of detection.

Electroencephalography (EEG) signals recording are the mixture of electrical potentials generated from different sources. These signals are influenced by different potentials. Currently, there exists no measure that can evaluate the measure influence among the signals. A new measure of influence has been proposed based on the distribution of correlation (DCOR) that quantifies the relative influence of constituent sub-band signals over full band signal. To estimate the inter-influence, scaled correlation analysis of signal sub-components is investigated. Results so obtained demonstrate that the signal influence of highest-frequency components present in the signal is more in case of linear/stationary signals, compared with non-linear/non-stationary (EEG/event related potential) signals. These findings are concluded with two types of analysis: (i) mixed influence analysis and (ii) mutual influence analysis. It is demonstrated that for separation of negative and positive correlations (CORs) using the proposed novel measure of signal influence (DCOR) is 14.24% better than other conventional COR method.

Forced convection of insulation oil is the main heat transfer mode in large-power and ultra-high-voltage (UHV) transformers. The electrification hazard caused by physicochemical phenomena between mineral oil and pressboard has been suspected to be responsible for several failures. The electrification measurement was carried out in an oil flow system. The influences of oil temperature, flow velocity, time and applied electric field of fresh and dry transformer oil have been investigated by a measurement system. The experimental results from the oil flow system show that the streaming current increases with the increase of the temperature when the temperature is below 50°C, while it reverses when the temperature is above 50°C. The streaming current increases with the increase of AC and DC electric fields under the different flow velocities, but the streaming current polarity reverses with DC electric field polarity under the 6.9 m/s flow velocity. The electrification phenomenon can lead to reduction of the breakdown strength of the oil. It is concluded that some effective measures should be taken to restrain the possible harm caused by the streaming electrification in UHV converter transformer.

Gas ultrasonic flowmeters are widely used in natural gas industry. When flow velocity achieves to tens of meters per second, the measurement error may appear significant non-linearity with flow velocity increased. In order to solve this problem, reasons of non-linearity are discussed based on the ray acoustics theory. First, the two-dimensional ray tracing method is introduced and realised by Matlab. Second, both DN100 and DN500 diametric single path gas ultrasonic flowmeters are simulated, respectively. The ultrasonic wave propagation trajectory, transit time, path angle and receiving position of transducer are analysed with increasing flow velocities 1–50 m/s. Third, it is noted that the assumption of traditional velocity measurement model is not consistent with the actual ultrasound propagation. Therefore, a corrected model is proposed. Through comparing results of traditional and corrected models, the measurement error is reduced up to 4%, and the measurement non-linearity is improved.

In this study, adaptive control of a two-axis gimbal system with actuator dynamics in the presence of parametric uncertainties is addressed. The considered gimbal system is a pointing antenna which can rotate over y and z axes and covers all line of sights. Adaptive dynamic surface control technique is used to overcome the ‘explosion of complexity’ problem which appears in adaptive backstepping control design. By using the Lyapunov stability analysis, the convergence of the tracking error to origin and boundedness of all closed-loop signals are guaranteed. Finally, excellent performance of the proposed method for tracking the desired trajectories and also the effectiveness of this technique for controlling a two-axis pointing antenna are shown for a real antenna model in ADAMS.

In the frame of power frequency electromagnetic interference problems on telecommunication cables and pipelines, the study presents a method to evaluate the shielding factor related to an urban environment. The calculation method is based on a Monte Carlo algorithm and the results are in agreement with the few ones present in literature. The novelty of the study consists in the approach to the problem which is based, for the first time, on modelling.

Previous electromagnetic (EM) wave-based approaches to evaluate material physical properties are focused on applications of GHz and THz. High-frequency radio-frequency identification (HF-RFID, 13.56 MHz) is low-cost and mostly used as communication solution. Material properties variation can be affected by damage (such as defects or fatigue). In this study, the authors present a preliminary study that applies HF-RFID on non-destructive testing and evaluation. The evaluation model of HF-RFID signal propagation characterisations under material EM properties variation is demonstrated. Simulations and experiments for oil debris monitoring and metal surface defect detection are demonstrated and simulations are in good agreement with experiment results. (i) In oil debris monitoring experiment, as the debris amount in the 25 ml breaker increases from 0.0 to 2.0 g, penetration signal decreases by 7.8% and reflected signal increases by 174.3%. (ii) In metal surface defect experiment, as the defect size increases from 1 to 5 mm, reflected signal decreases by 1.0%. The authors’ work also presents a blueprint for non-destructive testing method using other high-frequency devices.

A new technique for QRS complex detection of electrocardiogram signals, using particle swarm optimisation (PSO)-based adaptive filter (AF), is proposed. In the proposed method, the AF, based on PSO, is used to generate the feature. An effective detection algorithm, containing search-backs for missed peaks, is also proposed. In the experiment, five PSO variants are tested on MIT-BIH arrhythmia database. The linear decreasing inertia variant of PSO, achieves the best results with sensitivity, positive predictivity and detection error rate of 99.75, 99.83 and 0.42%, respectively. Effectiveness of the proposed method is validated by comparing fidelity parameter of proposed method with state-of-the-art methods.

The fixed maximum acceleration of current statistical model (CSM) will lead to the deterioration of Kalman filter. To improve the performance of CSM in target tracking, a new modified CSM (MCSM) and a new Kalman filter (KF) are proposed. The new model, which employs innovation dominated subjection function to adaptively adjust maximum acceleration, has a better performance in target tracking, but it is very sensitive to innovation and will lead to a fluctuant phenomenon when target manoeuvres occur. The new adaptive fading Kalman filter which is formed by amendatory KF (AKF) and adaptive fading KF can weaken the fluctuant phenomenon caused by MCSM. The principle and deducing of AKF are specifically elaborated based on probability theory. Three simulations results indicate the high performance and robustness of MCSM and MCSM-adaptive fading amendatory Kalman filter in target tracking.

In this study, three different insulating liquids, natural ester, mineral oil which is currently used by the Public Power Corporation of Greece and a nanofluid of surface coated Fe₃O₄ nanoparticles into a natural ester matrix, were subjected to AC voltage stress and their statistical breakdown voltage was measured and compared. Three different electrode configurations were used during the measurements in order to study the effect of non-uniform fields on the breakdown voltage distribution. Four different statistical distributions were used for the statistical processing of the experimental results. The two of them were the frequently used normal and Weibull distributions; in addition, Gumbel and generalised extreme value (GEV) function distributions were studied. It was shown that, in most cases, the experimental data followed GEV and Weibull functions rather than normal or Gumbel. Therefore, GEV statistics fits indiscriminately better to the experimental results concerning breakdown voltage, for the three different electrodes configuration and the three understudied insulating oils. The experimental results indicated that nanofluid has better performance, in terms of dielectric breakdown voltage, compared with natural ester oil and mineral oil, hence nanofluid is considered as a potential substitute of the conventional dielectric liquids, with enhanced properties and prospects.

The measurement of relative vessel positioning is important to prevent the risk of vessel collision or the deterioration of working efficiency. This study presents a vision-based system for measuring the relative position and heading between a vessel and a target object without the installation of transponders, reflectors, or markers. Such a markerless measurement system, which is not restricted by the presence or the absence of transponders, is a method of expanding feasible conditions for relative vessel positioning. The proposed system consists of multiple camera units that can measure the distance and direction between an initially designated point on a target object while keep track of the designated point. To evaluate the measurement performance for the proposed system, the authors conducted measurements by using a prototype system in water. The results demonstrated that the system can keep track of the designated points and accurately measure the position and heading of a vessel relative to a target object, despite the vessel's roll motion.

A new technique for approximate evaluation of a small slotted enclosure shielding effectiveness (SE) is proposed. The enclosure under test is equipped with a built-in, rotating, conductive stirrer, and the SE is determined for discrete angles of the stirrer position. The SE characteristics computed in the frequency domain for the enclosure with the stirrer are compared to those of the enclosure containing different arrangements of printed circuit boards. This study concludes that the inclusion of an internal stirrer is a potentially beneficial approach to SE testing.

This study presents the results of the measurements of electrical strength of pressboard specimens impregnated with three different liquid dielectrics: mineral oil, natural ester and synthetic ester. In the experiment carried out in accordance with IEC 60243 standard, two types of pressboard specimens of thicknesses 0.5 and 1 mm, respectively, were considered. The data obtained during the measurements in the form of breakdown voltages were used for calculation of the electrical strength. Both standard-based approach where median value was taken into account in calculations and statistical approach using three-parameter Weibull distribution function where location parameter V ₀ was considered were applied. The results obtained on the basis of both approaches showed that both the specimens impregnated with mineral oil and ester liquids gave the satisfactory results within the electrical strength determined, which in all cases was higher than minimum required for the impregnated pressboards. The differences indicating slightly better impregnation properties of mineral oil, when the same impregnation conditions are used, are noticeable especially in the case of location parameter of Weibull distribution function. However, these differences are small and in relation to the requirements for the impregnated pressboards may be treated as negligible.

Motivated by the need of reducing power consumption (PC) in two dimensional (2D) finite impulse response (FIR) filters, in this work, the 2D FIR filter design task is formulated as an optimisation problem that seeks to attain the desired frequency response and reduces PC. The optimisation problem has been solved using the modified version of artificial bee colony algorithm. The applicability of the proposed approach has been evaluated by designing circular shaped 2D FIR filters for a set of specifications in frequency domain. The designed filters have been compared with other reported state of the art techniques. The evaluation is carried out in terms of pass band and stop band ripple minimisation, convergence profile and PC during filter execution in hardware. The proposed technique is found to outperform all other techniques in achieving minimum ripple for a given filter order. To prove the effectiveness of the proposed approach for PC reduction, the designed filters have been implemented in hardware using field-programmable gate array (xc7vx485t-2ffg1761). The PC computed using Xilinx X-power analyser shows that 23.53% power can be saved using the proposed approach as compared with conventional design approaches.