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

PURPOSE The aim of this research was to identify and develop a PAL framework and activities with the following features: i) A focus on competencies developed throughout degree programs, rather than selected units, ii) involve and serve students across all years of their learning program, iii) enable and encourage students to take responsibility for developing, managing and sustaining PAL groups and activities. The research is being conducted in the context of an engineering degree program, but we are seeking to develop a framework that, with appropriate changes, will be relevant in any discipline.

Program-based peer assisted learning

Application of spinors to solving the Bloch equations.

We report the use of axicons to achieve broadband "focus-free" imaging in transmission and reflection at terahertz wavelengths. We demonstrate how the use of a broadband terahertz source improves the resolution of the imaging system, and how by using time-of-flight data the axial position and dimension of objects within the large depth of field of the axicon (160 mm) could be determined.

Broadband "focus-free" terahertz imaging using axicons

This paper presents design tradeoffs between PAPR and SFDR using an RF amplifier in an OFDM-RoF link, depending on number of subcarriers. PAPR degradation of 2 dB for 512 subcarriers showed SFDR gain of 25 dB.Hz2/3.

PAPR and SFDR of an OFDM-RoF link

BACKGROUND There is a saying that "you don't really know a subject until you've taught it." There is an element of truth in that which provides the foundation for the use of small group discussions and active learning methods, group projects, peer assessment, and "flipped classrooms". The latter model requires preparation by students before class (e.g. through directed reading and quizzes) then group discussions of concepts in class moderated by the instructor.

Graham Town

Papers

Program-based peer assisted learning

Application of spinors to solving the Bloch equations.

Broadband "focus-free" terahertz imaging using axicons

PAPR and SFDR of an OFDM-RoF link

Reflections on learning through peer convening