Single‐Stage ZVS‐PWM AC‐AC Power Converter Using All SiC Power Module for High‐Frequency Induction Heating Applications

This paper presents a novel prototype of a single‐stage zero voltage soft‐switching pulse‐width modulation ‐controlled ac‐ac converter with a silicon carbide (SiC)‐MOSFET/SiC‐SBD power module for high‐frequency (HF) induction heating (IH) applications. The newly developed ac‐ac converter can achieve higher efficiency than a Si‐IGBT/Si‐PN diode power module‐based prototype due to a low ON‐resistance of SiC‐MOSFET and a low forward voltage of SiC‐SBD under the condition of HF switching. The performances of the new prototype converter are evaluated by experiment with a single‐phase IH utensil of ferromagnetic stainless metal, after which the high‐efficiency and low switching noise characteristics due to the all SiC power module are actually demonstrated.     

Controlled Growth of Conductive AlN Thin Films by Plasma-Assisted Reactive Evaporation

Metallurgical and Materials Transactions A - In this work, the growth of conductive AlN thin films by plasma-assisted reactive evaporation at different filament-to-substrate distances was presented...     

Biogenerated silica nanoparticles synthesized from sticky,red, and brown rice husk ashes by a chemical method

An inexpensive chemical method was used to synthesize biogenic mesoporous silica (m-SiO₂) from rice husk ash (RHA). A comparative study was carried out to produce silica nanoparticles (S-SiO₂, R-SiO₂, and B-SiO₂) from three type of rice husk ashes (sticky, red, and brown). The microstructure of m-SiO₂ was dependent on the geographical provenance and the types of RHA. An analysis of the SEM and TEM micrographs reveals that the S-SiO₂ nanoparticles had a clustered spherical shape, while R-SiO₂ and B-SiO₂ nanoparticles were found to be purely spherical. The average crystallite size of S-SiO_2, R-SiO₂ and B-SiO₂ nanoparticles evaluated from the TEM measurements were observed to be 50, 20 and 10 nm, respectively. The XRD pattern of silica nanopowders had an absence of sharp peaks that confirmed the amorphous nature of the material. The Fourier transform infrared (FTIR) spectra of silica nanoparticles showed the symmetric Si–O and O–Si–O stretching bond vibrations at 462, 1088, and 1098 cm⁻¹. The surface area of S-SiO_2, R-SiO₂ and B-SiO₂ nanopowders was measured to be 7.5513, 201.45, and 247.18 m² g⁻¹, respectively. The surface area of uniformly-distributed spherical nanoparticles of B-SiO₂ was observed the highest, which can be applied for the application of energy storage and drug delivery systems.     

Issues and challenges impacting the successful management of agile-hybrid projects: A grounded theory approach

The demand for success in agile projects requires serious attention in addressing its issues and challenges, besides merely implementing suitable agile methods. A comprehensive number of factors have been discussed in the literature, but it does not reflect the crucial challenges confronted by the Information Technology industry. This study utilises a Grounded Theory approach, to capture 38 unique issues and challenges faced by 42 participating industry practitioners, through several rounds of interviews. The issues and challenges, simplified as factors, were grouped into Organisation, People, Process and Technical categories. The proposed mitigation methods were also captured, and mapped into a framework, to be used as a guide to manage agile-hybrid projects. Most factors were related to the process and people categories. Key issues were in the areas of executive support, misalignment of agile methods with the business objectives, deficient understanding of agile principles, lack of teamwork and inadequate skillset of the project stakeholders.     

Gamification Solutions to Enhance Software User Engagement—A Systematic Review

Gamification is the use of video-game mechanics and elements in nongame contexts to enhance user engagement and performance. The purpose of this study is to conduct a systematic review to have an in-depth investigation into the existing gamification solutions targeted at solving user engagement problems in different categories of software. We carried out this systematic review by proposing a framework of gamifying process, which is the basis for comparison of existing gamification solutions. In order to report the review, the primary studies are categorized according to the following: a) gamified software and their platforms; b) elements of the gamifying process; c) gamification solutions in each software type; d) gamification solutions for software user engagement problems; e) gamification solutions in general; and f) effects of gamification on software user engagement and performance. Based on the search procedure and criteria, a total of 78 primary studies were extracted. Most of the studies focused on educational and social software, which were developed for web or mobile platforms. We concluded that the number of studies on motivating users to use software content, solving problems in learning software, and using real identity is very limited. Furthermore, few studies have been carried out on gamifying the following software categories: productivity software, cloud storage, utility software, entertainment software, search engine software, tool software, fitness software, software engineering, information worker software, and health-care software. In addition, a large number of gamification solutions are relatively simple and require improvement. Thus, for future studies, researchers can work on the items discovered in this review; they can improve the quality of the current gamified systems by using a wide variety of game mechanics and interface elements, utilizing a combination of contextual types of rewards and giving users the ability to use received rewards “in-game” and “out-game.”     

Cryptographic Boolean functions: One output,many design criteria

Boolean functions represent an important primitive in the design of various cryptographic algorithms. There exist several well-known schemes where a Boolean function is used to add nonlinearity to the cipher. Thus, methods to generate Boolean functions that possess good cryptographic properties present an important research goal. Among other techniques, evolutionary computation has proved to be a well-suited approach for this problem. In this paper, we present three different objective functions, where each inspects important cryptographic properties of Boolean functions, and examine four evolutionary algorithms. Our research confirms previous results, but also sheds new insights on the effectiveness and comparison of different evolutionary algorithms for this problem.     

A novel evolutionary-negative correlated mixture of experts model in tourism demand estimation

Mixtures of experts (ME) model are widely used in many different areas as a recognized ensemble learning approach to account for nonlinearities and other complexities in the data, such as time series estimation. With the aim of developing an accurate tourism demand time series estimation model, a mixture of experts model called LSPME (Lag Space Projected ME) is presented by combining ideas from subspace projection methods and negative correlation learning (NCL). The LSPME uses a new cluster-based lag space projection (CLSP) method to automatically obtain input space to train each expert focused on the difficult instances at each step of the boosting approach. For training experts of the LSPME, a new NCL algorithm called Sequential Evolutionary NCL algorithm (SENCL) is proposed that uses a moving average for the correlation penalty term in the error function of each expert to measure the error correlation between it and its previous experts. The LSPME model was compared with other ensemble models using monthly tourist arrivals to Japan from four markets: The United States, United Kingdom, Hong Kong and Taiwan. The experimental results show that the estimation accuracy of the proposed LSPME model is significantly better than the other ensemble models and can be considered to be a promising alternative for time series estimation problems.     

Modal-based damage identification for the nonlinear model of modern wind turbine blade

In this paper, the modal-based indices are used in damage identification of the wind turbine blade. In contrast of many of previous researches, the geometric nonlinearity due to the large structural deformation of the modern wind turbines blade is considered. In the first step, the finite element model (FEM) of the rotating blade is solved to obtain the modal features of the deformed structure under operational aerodynamic loading. Next, the accuracy and efficiency of the various modal-based damage indices including the frequency, mode shape, curvature of mode shape, modal assurance, modal strain energy (MSE) and the difference of indices (between the intact and damaged blades) are investigated. To adapt the MSE index calculation in nonlinear modeling, a new approach is introduced to include the effects of the structural nonlinearity. Furthermore, the effect of the damage length, its location and severity and also the effect of rotational speed and amplitude of loading are studied. The generic 5-MW NREL blade is used for the simulation study. The results show enough sensitivity of the mode shape curvature and MSE indices to the local damages. Moreover, the importance of geometric nonlinearity in the damage detection of the modern wind turbines is demonstrated.     

Consuming,sharing, and creating content: How young students use new social media in and outside school

This survey study investigated 186 secondary 2–5 school students from two schools to understand how and why they used new social media both in and outside of school to consume, share, and create content. It found that whereas students tend to consume and share more social media content outside of school they create more in school. Perceived importance of sharing content with peers or others is the most significant predictor having positive impact on all social media activities, both in and outside school. However, the negative impact of self-regulation ability on outside school social media activities implies the conscientiousness of their social media engagement, which calls for a further investigation on the quality of the social media content.