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

A simplified shoot-through pulse width modulation (PWM) technique is presented for reducing switching losses in impedance source DC-DC converters. The proposed PWM method alternates shoot-through state conduction in each leg of the H-bridge, thereby increasing controllability of the converter, reducing the number of switching transients, and reducing the dynamic loss of the converter through soft-switching. The proposed modulation method was verified using a GaN-based quasi-Z-source DC-DC converter. This method demonstrates better performance at low load and with high switching frequency.

A new PWM shoot-through control technique to reduce switching losses in impendance source DC/DC converters

In this paper, we report on different polymeric 2D photonic crystal filters for THz frequencies which are fabricated by a standard fiber drawing technique. The bandstop filters were simulated and designed by the generalized multipole technique (GMT). The frequency and angle dependent transmission characteristics of the photonic crystal structures were characterized in a pulsed terahertz (THz) time domain spectrometer.

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Fiber drawn 2D polymeric photonic crystal THz filters

Solar energy for biofuel extraction

We describe a delta-k electro-optic modulator for 1310 nm using a multi-channel directional coupler structure. The device employs a poled electro-optic polymer material for the cladding layer.

A delta-k electro-optic polymer modulator using a multi-channel directional coupler

Several approaches to improving the student experience and learning outcomes in engineering education have been proposed, including active learning (e.g. flipped classrooms), project based learning, problem based learning (PBL), peer assisted learning (classroom or project based), peer convening, etc. Some of these approaches have been shown to be very effective at motivating student learning, whilst also developing generic and professional engineering skills (e.g. teamwork, project management.)

Graham Town

Papers

A new PWM shoot-through control technique to reduce switching losses in impendance source DC/DC converters

Fiber drawn 2D polymeric photonic crystal THz filters

Solar energy for biofuel extraction

A delta-k electro-optic polymer modulator using a multi-channel directional coupler

Integrated engineering - implementation and transition