157 research outputs found

    Analysis of an Inverse Problem Arising in Photolithography

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    We consider the inverse problem of determining an optical mask that produces a desired circuit pattern in photolithography. We set the problem as a shape design problem in which the unknown is a two-dimensional domain. The relationship between the target shape and the unknown is modeled through diffractive optics. We develop a variational formulation that is well-posed and propose an approximation that can be shown to have convergence properties. The approximate problem can serve as a foundation to numerical methods.Comment: 28 pages, 1 figur

    Three-Phase Grid-Connected of Photovoltaic Generator Using Nonlinear Control

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    SOIL MOISTURE MAPPING USING SMOS APPLIED TO FLOOD MONITORING IN THE MOROCCAN CONTEXT

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    Soil moisture is an important parameter in many fields: hydrological, agricultural and even natural hazards monitoring (like floods). And, since soil moisture is crucial to flood monitoring a soil moisture spatial mission was launched in the 2nd November 2009: Soil Moisture And Ocean Salinity (SMOS). In this context, two Moroccan flood events are considered: November 2014 floods at Guelmim and Sidi Ifni and 23rd February 2017 floods at Rabat and SalĂ©. The methodology is based on the combination of the observation of two parameters: soil moisture (satellite data) and rainfall data (in-situ and satellite-based data) in order to have a vision of the flood risk in Morocco in the future with the comparison of Rainfall and soil moisture maps before and after the flood events. Among the main results, a strong relation between soil moisture and floods was detected for the November 2014 floods (for Guelmim soil moisture reached 0.6 m3/m3 on 20 and 21 November 2014) and between Rainfall amount and floods for the 23 February 2017 floods (119 mm on the day of the flood event)

    Modeling and Nonlinear Control of Electric Power Stage in Hybrid Electric Vehicle

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    Multi-Channel Configuration for improving received signal strength in non-line-of-sight environments of indoor visible light communication localization

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    In modern engineering technologies, energy conservation is a factor of primary concern. A feature of Light-emitting diode (LED) light sources is the ability to transmit information in addition to illumination at no additional cost. VLC (Visible Light Communication) is gaining an upper hand over the traditional RF data communication model, as it utilizes a technology by which light can be used to transmit data. It is commonly seen that dealing with non-line of sight (NLOS) is a major challenge for VLC systems as the light intensity is reflected in a variety of directions. To overcome this drawback, a new technique based on multichannel configuration is utilized to enhance the overall system performance. An indoor VLC model is designed and simulated on the basis of the eye-diagram, bit error rate, and received power of the proposed model. We also investigated the model under the influence of ambient light noise. The corresponding results are compared with the conventional NLOS system and an inference made shows the significant improvement for the next-generation optical communication system

    BIG HEALTH DATA: A SYSTEMATIC MAPPING STUDY

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    The Big Data, a result of the digital revolution, offers several opportunities in the field of health. Indeed, appliances and applications permanently connected to humans and the global digitalization of medical documents produce a vast health data: "Big Health Data". This data is the subject of several projects in the world given the opportunities offered to optimize this area. This paper focuses on quantifying the production of scientific articles about Big Health Data research and the most investigated Big Health Data topics. It also presents a mapping of countries producing articles about this subject. In remote sensing using real time categories, we aimed to quantify articles dealing with “big data architectures”, technologies and data sources used. A systematic mapping study was conducted with a set of seven research questions by investigating articles from two digital libraries: Scopus and Springer. The study concern articles published in 2017 and the first half of 2018. The results are illustrated by diagrams answering each question from which a set of recommendations are concluded in this area of research. The study shows that this Data is used the most in studies of oncology. Statistics show that while remote sensing and monitoring is a hot topic, real-time use is not as interesting. It was found that there’s a lack in studies interested in big data technologies used in real time remote sensing in the field of health. In conclusion, we recommend more focus on research area treating architecture in remote sensing real time Big Health Data systems combined with geolocation

    Challenges Facing Distance Education for Children in Virtual Kindergartens

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    For kindergarten children, distance education was neither an alternative nor a potential option to in-person schooling before the global COVID-19 pandemic-imposed isolation and mandatory social distancing measures. These measures guaranteed the safety of school staff and children and made the adoption of distance education an urgent necessity for children to continue their education safely. The current study was conducted to reveal the most common challenges that faced children’s distance education in virtual kindergartens. The study was conducted from the teachers’ point of view to determine the impact of each of the job title variables and years of experience. The study sample consisted of 32 kindergarten teachers in Jubail Governorate. The research team applied the scale of challenges facing children’s education in virtual kindergarten. The results of the study concluded that the most important challenges facing children’s education in virtual kindergartens were related to communication skills (79.9%), technical skills (79.5%), educational aids (76.4%), and motivation (69.6%). The results of the study also revealed that there were statistically significant differences in the challenges related to motivation and readiness and in the total challenges facing children’s education in the virtual kindergarten from the teachers’ point of view depending on the job title—that is, the assistant teacher where the calculated “U” value reached 28.5 and 37.5. In addition, there was an absence of statistically significant differences due to the variable years of experience, whether in the total number of challenges or in the dimensions of the scale, except for the dimension of communication skills, where the calculated “Ka2” value reached 8.755, which is a statistically significant value at the level of significance (0.05)

    FUSING OF OPTICAL AND SYNTHETIC APERTURE RADAR (SAR) REMOTE SENSING DATA: A SYSTEMATIC LITERATURE REVIEW (SLR)

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    Remote sensing and image fusion have recognized many important improvements throughout the recent years, especially fusion of optical and synthetic aperture radar (SAR), there are so many published papers that worked on fusing optical and SAR data which used in many application fields in remote sensing such as Land use Mapping and monitoring. The goal of this survey paper is to summarize and synthesize the published articles from 2013 to 2018 which focused on the fusion of Optical and synthetic aperture radar (SAR) remote sensing data in a systematic literature review (SLR), based on the pre-published articles on indexed database related to this subject and outlining the latest techniques as well as the most used methods. In addition this paper highlights the most popular image fusion methods in this blending type. After conducting many researches in the indexed databases by using different key words related to the topic “fusion Optical and SAR in remote sensing”, among 705 articles, chosen 83 articles, which match our inclusion criteria and research questions as results ,all the systematic study ‘ questions have been answered and discussed
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