There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

A topical review of numerical and experimental studies of supercontinuum generation in photonic crystal fiber is presented over the full range of experimentally reported parameters, from the femtosecond to the continuous-wave regime. Results from numerical simulations are used to discuss the temporal and spectral characteristics of the supercontinuum, and to interpret the physics of the underlying spectral broadening processes. Particular attention is given to the case of supercontinuum generation seeded by femtosecond pulses in the anomalous group velocity dispersion regime of photonic crystal fiber, where the processes of soliton fission, stimulated Raman scattering, and dispersive wave generation are reviewed in detail. The corresponding intensity and phase stability properties of the supercontinuum spectra generated under different conditions are also discussed.

Supercontinuum generation in photonic crystal fiber

This Review explains the concept of dissipative solitons and their application to high-energy mode-locked fibre laser cavities. Dynamics and effects such as dissipative soliton ‘explosions’ and ‘rain’ are summarized, and an outlook of the field is also provided.

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Dissipative solitons for mode-locked lasers

DC–DC converters with voltage boost capability are widely used in a large number of power conversion applications, from fraction-of-volt to tens of thousands of volts at power levels from milliwatts to megawatts. The literature has reported on various voltage-boosting techniques, in which fundamental energy storing elements (inductors and capacitors) and/or transformers in conjunction with switch(es) and diode(s) are utilized in the circuit. These techniques include switched capacitor (charge pump), voltage multiplier, switched inductor/voltage lift, magnetic coupling, and multistage/-level, and each has its own merits and demerits depending on application, in terms of cost, complexity, power density, reliability, and efficiency. To meet the growing demand for such applications, new power converter topologies that use the above voltage-boosting techniques, as well as some active and passive components, are continuously being proposed. The permutations and combinations of the various voltage-boosting techniques with additional components in a circuit allow for numerous new topologies and configurations, which are often confusing and difficult to follow. Therefore, to present a clear picture on the general law and framework of the development of next-generation step-up dc–dc converters, this paper aims to comprehensively review and classify various step-up dc–dc converters based on their characteristics and voltage-boosting techniques. In addition, the advantages and disadvantages of these voltage-boosting techniques and associated converters are discussed in detail. Finally, broad applications of dc–dc converters are presented and summarized with comparative study of different voltage-boosting techniques.

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Step-Up DC–DC Converters: A Comprehensive Review of Voltage-Boosting Techniques, Topologies, and Applications

The Internet of Things (IoT) is the next era of communication. Using the IoT, physical objects can be empowered to create, receive, and exchange data in a seamless manner. Various IoT applications focus on automating different tasks and are trying to empower the inanimate physical objects to act without any human intervention. The existing and upcoming IoT applications are highly promising to increase the level of comfort, efficiency, and automation for the users. To be able to implement such a world in an ever-growing fashion requires high security, privacy, authentication, and recovery from attacks. In this regard, it is imperative to make the required changes in the architecture of the IoT applications for achieving end-to-end secure IoT environments. In this paper, a detailed review of the security-related challenges and sources of threat in the IoT applications is presented. After discussing the security issues, various emerging and existing technologies focused on achieving a high degree of trust in the IoT applications are discussed. Four different technologies, blockchain, fog computing, edge computing, and machine learning, to increase the level of security in IoT are discussed.

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A Survey on IoT Security: Application Areas, Security Threats, and Solution Architectures

High penetration of electric vehicles with unmanaged clustered charging will cause unwanted peaks in the electric network. It is important for the system operator to manage the impact of EV charging on the power system. This work developed a model to construct the aggregated charging load due to EVs in a parking lot while considering EV travel patterns, usage and charging needs. The EV charging load was combined with the system load to determine the reliability of the composite power system. IEEE-RTS 24 bus was used as a test system to demonstrate the efficacy of the proposed method. The DC load flow with linear programming having an objective function of minimum load curtailment was carried out to evaluate the reliability index (i.e. loss of load probability (LOLP)). The model has been validated for Shopping Center Parking Lots. Results showed that due to uncontrolled charging of EVs, the LOLP of the power system could reach up to2.3% in peak hours, whereas acceptable LOLP is < 1%. However, to maintain the reliability of the power system, it is recommended to either manage or limit the load assigned to parking lots equipped with EV chargers.

Reliability Assessment Considering Intermittent Usage of Electric Vehicles in Parking Lots

We describe a numerical model, based on a Monte Carlo algorithm, to calculate the propagation of polarized waves through highly scattering microstructured materials, and to properly account for the effect of both loss and boundaries. As an example, we investigate the impact of a strongly scattering object of air-polymer composite material on a broadband collimated source. We also calculate the depolarization of linearly polarized and circularly polarized waves escaping from the sample boundaries, especially at large scattering angles, and we show how boundaries can modify the distribution and the polarization of the scattered waves propagating out of the sample.

Propagation of polarized waves through bounded composite materials

We describe an electro-optic polymer modulator for 1310 nm using a multi-channel directional coupler structure, and examine various electrode structures.

An electro-optic modulator using a multi-channel directional coupler with a poled electro-optic polymer

We report the generation of microwave signals by mixing a tunable semiconductor laser with a short-cavity dual- wavelength distributed Bragg reflector (DBR) fiber laser. The DBR laser generated two continuous-wave longitudinal modes separated by 25GHz.

Microwave frequency generation using a dual-wavelength DBR fiber laser

A magnetic resonance imaging system for investigation and development of nuclear magnetic resonance (NMR) imaging techniques is being constructed by the NMR, Imaging Group within the School of Electrical Engineering at the University of Sydney. The system will also be capable of spatially-localized in-vivo spectroscopy. Primary requirements of a research instrument are flexibility and low cost, precluding purchase of a commercial system and necessitating in-house construction. The appropriate design strategy adopted was to start by building a simple NMR apparatus and expand it in steps, progressing towards a complete imaging and spectroscopy system.

Graham Town

Papers

Reliability Assessment Considering Intermittent Usage of Electric Vehicles in Parking Lots

Propagation of polarized waves through bounded composite materials

An electro-optic modulator using a multi-channel directional coupler with a poled electro-optic polymer

Microwave frequency generation using a dual-wavelength DBR fiber laser

Design and construction of "SUMRIS"--the Sydney University magnetic resonance imaging system.