Amateur radio sensing technique using a combination of energy detection and waveform classification

<p>A critical problem in spectrum sensing is to create a detection algorithm and test statistics. The existing approaches employ the energy level of each channel of interest. However, this feature cannot accurately characterize the actual application of public amateur radio. The transmitted signal is not continuous and may consist only of a carrier frequency without information. This paper proposes a novel energy detection and waveform feature classification (EDWC) algorithm to detect speech signals in public frequency bands based on energy detection and supervised machine learning. The energy level, descriptive statistics, and spectral measurements of radio channels are treated as feature vectors and classifiers to determine whether the signal is speech or noise. The algorithm is validated using actual frequency modulation (FM) broadcasting and public amateur signals. The proposed EDWC algorithm's performance is evaluated in terms of training duration, classification time, and receiver operating characteristic. The simulation and experimental outcomes show that the EDWC can distinguish and classify waveform characteristics for spectrum sensing purposes, particularly for the public amateur use case. The novel technical results can detect and classify public radio frequency signals as voice signals for speech communication or just noise, which is essential and can be applied in security aspects.</p>

Robust ferromagnetic insulating and large exchange bias in LaMnO3:CoO composite thin films

Ferromagnetic insulators have received widespread attention for applications in novel low power consumption spintronic devices. Further optimizing the robust ferromagnetic insulating and developing multifunctional ferromagnetic insulator by integrating other magnetic property can not only ease or pave the way for actual application, but also provide an additional freedom degree for device designing. In this work, by introducing antiferromagnetic CoO into ferromagnetic insulator LaMnO3, we have constructed (1-x)LaMnO3:xCoO composite thin films. The films simultaneously show robust ferromagnetic insulator characteristics and large exchange bias. For x = 0.5 sample, the resistivity is 120 Ω·cm at 250 K while the magnetization is 100 emu/cm3 and the exchange bias field is -2200 Oe at 10 K. Especially, the blocking temperature is up to 140 K. Synchrotron radiation x-ray absorption spectroscopy reveals the coexistence of Mn3+, Mn2+, Co2+ and Co3+, arising from interfacial charge transfer and space charge/defect trapping, should be responsible for the enhanced and integrated multifunctional magnetic properties.

From the Discovery of Extremozymes to an Enzymatic Product: Roadmap Based on Their Applications

With the advent of the industrial revolution, the use of toxic compounds has grown exponentially, leading to a considerable pollution of the environment. Consequently, the development of more environmentally conscious technologies is an urgent need. Industrial biocatalysis appears as one potential solution, where a higher demand for more robust enzymes aims to replace toxic chemical catalysts. To date, most of the commercially available enzymes are of mesophilic origin, displaying optimal activity in narrow ranges of temperature and pH (i.e., between 20°C and 45°C, neutral pH), limiting their actual application under industrial reaction settings, where they usually underperform, requiring larger quantities to compensate loss of activity. In order to obtain novel biocatalysts better suited for industrial conditions, an efficient solution is to take advantage of nature by searching and discovering enzymes from extremophiles. These microorganisms and their macromolecules have already adapted to thrive in environments that present extreme physicochemical conditions. Hence, extremophilic enzymes stand out for showing higher activity, stability, and robustness than their mesophilic counterparts, being able to carry out reactions at nonstandard conditions. In this brief research report we describe three examples to illustrate a stepwise strategy for the development and production of commercial extremozymes, including a catalase from an Antarctic psychrotolerant microorganism, a laccase from a thermoalkaliphilic bacterium isolated from a hot spring and an amine-transaminase from a thermophilic bacterium isolated from a geothermal site in Antarctica. We will also explore some of their interesting biotechnological applications and comparisons with commercial enzymes.

Dynamic Modeling and Analysis of Micro-Video Teaching System Based on Cloud Computing in College English Teaching

The era is developing and the society is improving. The application research of computer technology in the field of education is a hot topic at present. The cultivation of talents required the training of schools and teachers. How to cultivate talented person who meets the needs of society lied in the comprehensive ability of teaching in colleges and universities, so the college English education professional grammar teaching model is studied based on dynamic programming algorithm. After a brief overview of the dynamic rule algorithm, an algorithm for evaluating English grammar learning in colleges and universities is designed by using dynamic algorithm. The algorithm is composed of dynamic rule algorithm, language processing technology, and regular expression. In the subsequent experiments, it is proved that the algorithm has a good evaluation effect and can meet the actual application requirements.

Towards a Multilingual Preschool Policy

The effects of immersive strategies and the benefits of a multilingual language policy have been extensively explored in the literature; however, it is valuable to look at the actual application of a multilingual policy. Putting linguistic-educational research into practice by implementing a transformative pedagogical approach is characterized by a process of trial and error, which has remained understudied. This chapter aims to fill this gap by adopting a case study approach that focuses on the implementation of a multilingual/cultural policy at a preschool in the Dutch-speaking part of Belgium. More than half of the children attending the preschool come from a multilingual background. Based on ethnographic fieldwork, consisting of observations, participations, interviews, and focus group discussions with different stakeholders, this chapter analyzes the mechanisms behind the preschool's switch from negatively undergoing multilingualism to positively engaging with it.

Digital Transformation Process in Selection and Implementation of an Electronic Document Management System

An electronic document management system (e-DMS) is an information system that allows creating, distributing, filing, storing, searching, destroying, and archiving documents concerning certain criteria and standards as a critical part of every digital transformation. It is known that correspondence processes in public institutions such as universities are time-consuming activities that increase workload and bureaucracy. Therefore, it is a critical issue to select and implement the suitable e-DMS software which systematically supports institutions in managing the documents they produce in their work processes. This chapter provides decision support to the institutional managers for selecting proper software, the preparation process before the application, transformation stages, and the environmental benefits after the implementation of the system are shown with their workflows through an actual application in a university. Digital transformation of the system provides both environmental and social benefits for institutions beside its material benefits such as time and labour.

Scaling of RC Chimney for the Experimental Investigation under Lateral Load

Reinforced concrete chimneys are tall industrial structures specially used in power plants to expel waste gases at high enough elevation. Based on the study of various literature available for the subject, various geometrical, material, and loading parameters to be followed to prepare the test specimens are presented in this paper so that the test specimen represents the behaviour of the actual RC chimney. The special construction process required to be followed is described in this paper along with the various analytical checks to be performed before the actual application of lateral loads on test specimens. Different design standards give different design recommendations mainly in terms of the stress-strain curve of concrete and steel. So, various experimental tests performed by applying the lateral load on specially designed and casted test specimens which represents the actual chimney in the field helps the researchers to compare the various design standards and helps the industry to opt for the same.

Field Robotics: Applications and Fundamentals

Field robotics is an area that is impelled by an application-driven approach by its nature. In this paper, I first review certain actual application areas of field robotics. Then, I discuss the current status of the application of field robotics in three common technologies: (1) mapping and path planning; (2) self-localization, recognition, and decision-making; and (3) dynamics and control. I then conclude by presenting future perspectives.

Rapid Aging as a Key to Understand Deactivation of Ni/Al2O3 Catalysts Applied for the CO2 Methanation

We developed a rapid aging method for Ni/Al2O3 methanation catalysts mimicking the real aging in the actual application. The method is based on hydrothermal deactivation of the catalyst at 600 or 700 °C, which leads to a catalyst with nearly constant conversion after a much shorter time period compared to normal aging. The hydrothermally aged catalysts are characterized by N2 adsorption, X-ray powder diffraction, temperature-programmed reduction and H2 chemisorption. The catalytic performance of the aged catalysts is comparable to the one of a catalyst deactivated in a long-term measurement with up to 720 h on stream. The time needed for reaching a stable conversion can be diminished by rapid aging by a factor of 10. The investigations also showed that the long-term deactivation is caused by Ni particle sintering and that the support pores limit the Ni particle size. Graphical Abstract

Mathematical modeling to optimize production planning and scheduling in a small foundry with multiple alternating furnaces

Purpose - This study presents an extension to a model in the literature for lot-sizing and scheduling in a small foundry with multiple alternate furnaces. The purpose of the model is to minimize delays and inventory costs. In addition, it determines the best use of the load capacity in the furnaces. Theoretical framework – Lot-sizing in foundries in the marketplace is a subject of academic interest due to its applicability and mathematical and computational complexity. Many papers address the production problem in foundries with a single furnace, however, few papers address the possibility of multiple furnaces. Design/methodology/approach - Mathematical modeling was used to represent the lot-sizing and scheduling problem in a small foundry. Data from the company's order books were collected and model validation questionnaires were applied. Findings - The extended model was able to generate good production plans at different planning horizons, with better performance than the current methods obtained by the company. Originality/value - the extension of the model contributes to the literature by addressing the existence of multiple non-simultaneous furnaces, a feature that has not been greatly explored. A comparison with other models is performed to indicate the most suitable model for actual application. Keywords: Alloys scheduling. Foundry. Lot size. Mixed integer programming.