This work proposes a novel approach for real-time video mosaicking facilitating drift-free mosaic construction and visualisation, with integrated frame blending and redundancy management, that is shown to be flexible to a range of varying mosaic scenarios. The approach supports unconstrained camera motion with in-sequence loop closing, variation in camera focal distance (zoom) and recovery from video sequence breaks. Real-time performance, over extended duration sequences, is realised via novel aspects of frame management within the mosaic representation and thus avoiding the high data redundancy associated with temporally dense, spatially overlapping video frame inputs. This managed set of image frames is visualised in real time using a dynamic mosaic representation of overlapping textured graphics primitives in place of the traditional globally constructed, and hence frequently reconstructed, mosaic image. Within this formulation, subsequent optimisation occurring during online construction can thus efficiency adjust relative frame positions via simple primitive position transforms. Effective visualisation is similarly facilitated by online inter-frame blending to overcome the illumination and colour variance associated with modern camera hardware. The evaluation illustrates overall robustness in video mosaic construction under a diverse range of conditions including indoor and outdoor environments, varying illumination and presence of in-scene motion on varying computational platforms.

Transient rotor angle stability assessment and oscillatory rotor angle stability assessment subsequent to a contingency are integral components of dynamic security assessment (DSA) in power systems. This study proposes a hybrid algorithm to determine whether the post-fault power system is secure due to both transient rotor angle stability and oscillatory rotor angle stability subsequent to a set of known contingencies. The hybrid algorithm first uses a new security measure developed based on the concept of Lyapunov exponents (LEs) to determine the transient security of the post-fault power system. Later, the transient secure power swing curves are analysed using an improved Prony algorithm which extracts the dominant oscillatory modes and estimates their damping ratios. The damping ratio is a security measure about the oscillatory security of the post-fault power system subsequent to the contingency. The suitability of the proposed hybrid algorithm for DSA in power systems is illustrated using different contingencies of a 16-generator 68-bus test system and a 50-generator 470-bus test system. The accuracy of the stability conclusions and the acceptable computational burden indicate that the proposed hybrid algorithm is suitable for real-time security assessment with respect to both transient rotor angle stability and oscillatory rotor angle stability under multiple contingencies of the power system.

A novel compact rat-race ring coupler with meander high-impedance transmission line and port impedance matching is presented in this Letter. First, a ring coupler with high port impedance is designed using meander lines. Secondly, an impedance matching section is designed to match the high port impedance to ordinary 50 Ω. The proposed coupler effectively reduces occupied area to 16.8% of conventional one. The design is validated both by simulation and measurement.

A novel coplanar waveguide-fed ultra-wideband antenna with triple band-notched function centred at 3.5, 5.5 and 7.5 GHz is proposed. It has small size of 26 × 26 mm². This antenna consists of an elliptical radiator and a square ground plane with an elliptical slot on one side of the substrate. Besides, two circles with a radius of 2 mm were dug from the edge of the outer ellipse to realise the bandwidth requirement. To avoid interference from Worldwide Interoperability for Microwave Access, a single open-ended elliptical arc-shaped slot was etched on the top side of the ground. Moreover, another elliptical arc-shaped slot notched at wireless local area network band was etched on the elliptical radiator and two systemically C-shaped slots working at 7.3–7.7 GHz was embedded on the structure. Measured voltage standing wave ratio shows the working frequency range was from 3.1 to 13.5 GHz except for notched bands of 3.35–3.8, 5.1–5.9 and 7.35–7.8 GHz.

Flexible heterogeneous substrates have been constructed, using three-dimensional printing in a single process, by introducing air-filled slots. These substrates have been used to substantially reduce the substrate losses for a flexible microstrip patch antenna causing an increase in its radiation efficiency. By combining transverse magnetic (TM)10 and TM01 modes the bandwidth of this antenna has also been increased.

Reliability enhancement of power distribution system has attained much significance in the present competitive electricity market. Accordingly, methodologies to assess and improve distribution system reliability are also gaining much importance. This study proposes oppositional differential search (ODS) algorithm to solve reliability optimisation problem of radial distribution system. The objective of this study is to obtain the optimum number, size and location of distributed generation as well as optimal number and location of remote control switch simultaneously in radial distribution system in order to improve system reliability at a compromised cost. A multi-objective function has been formulated here. Differential search (DS) algorithm imitates the seasonal migration behaviour of an organism in search of efficiency of food areas. Opposition-based DS (ODS) algorithm has been used here to improve the quality of solution in minimum time. The proposed opposition-based DS (ODS) algorithm utilises opposition-based learning for Superorganism initialisation and also for iteration wise update operation. Simulation results obtained by ODS algorithm have been compared with that of DS algorithm and differential evolutionary algorithm. Simulation results reveal that ODS algorithm provides considerably superior performance, in terms of quality of solution obtained and computational efficiency.

Code-division multiple access technology is widely used in telecommunications and its performance has been extensively investigated in the past. Theoretical results for the case of wide-band transmission channel were not available until recently. The novel formulae which have been published in 2014 can have an important impact on the future of wireless multiuser communications, but limitations come from the Gaussian approximations used in their derivation. In this Letter, the authors obtain more accurate expressions of the bit error rate (BER) for the case when the model of the wide-band channel is two-ray, with Rayleigh fading. In the authors’ approach, the spreading sequences are assumed to be generated by logistic map given by Chebyshev polynomial function of order two. Their theoretical and experimental results show clearly that the previous results on BER, which rely on the crude Gaussian approximation, are over-pessimistic.