The applications of neural network in mapping, modeling and change detection using remotely sensed data

Thesis (Ph.D.)--Boston UniversityAdvances in remote sensing and associated capabilities are expected to proceed in a number of ways in the era of the Earth Observing System (EOS). More complex multitemporal, multi-source data sets will become available, requiring more sophisticated analysis methods. This research explores the applications of artificial neural networks in land-cover mapping, forward and inverse canopy modeling and change detection. For land-cover mapping a multi-layer feed-forward neural network produced 89% classification accuracy using a single band of multi-angle data from the Advanced Solidstate Array Spectroradiometer (ASAS). The principal results include the following: directional radiance measurements contain much useful information for discrimination among land-cover classes; the combination of multi-angle and multi-spectral data improves the overall classification accuracy compared with a single multi-angle band; and neural networks can successfully learn class discrimination from directional data or multi-domain data. Forward canopy modeling shows that a multi-layer feed-forward neural network is able to predict the bidirectional reflectance distribution function (BRDF) of different canopy sites with 90% accuracy. Analysis of the signal captured by the network indicates that the canopy structural parameters, and illumination and viewing geometry, are essential for predicting the BRDF of vegetated surfaces. The inverse neural network model shows that the R2 between the network-predicted canopy parameters and the actual canopy parameters is 0.85 for canopy density and 0.75 for both the crown shape and the height parameters. [TRUNCATED

Modelling bidirectional radiance measurements collected by the advanced solid-state array spectroradiometer over Oregon transect conifer forests

Thesis (M.A.)--Boston UniversityThe primary objective of this research is to test and validate a geometric-optical bidirectional reflectance canopy model developed by Li and Strahler, with respect to actual forest canopy reflectance measurments. This model treats forest canopies as scenes of discrete, three dimensional objects that are illuminated and viewed from different positions in the hemisphere. The shapes of the objects, their count densities and patterns of placement are the driving variables, and they condition the mixture of sunlit and shaded objects and background that is observed from a particular viewing direction, given a direction of illumination. This mixture, in turn, controls the brightness apparent to an observer or a radiometric instrument. The Advanced Solid-State Array Spectroradiometer (ASAS) is chosen to be the sensor having the ability of collecting measurements at various look angles and its imaged reflectance was used to validate the model. The modelled BRF's were compared to actual ASAS measured BRF's in sites with different canopy structures and densities. The comparision revealed execellent match between the modelled and measured reflectance, and great ability of the model in predicting the shape and magnitude of the BRDF, in almost all the sites investigated. It is concluded that the geometric optics approach provided a good way to model the bidirectional reflectance distribution function of natural vegetation canopies, that captures the most important features exhibited by bidirectional measurements of such canopies. Further modifications have been suggested that will improve the predicted BRF's, and yield better results. [TRUNCATED

Improved drive current in RF vertical MOSFETS using hydrogen anneal

This letter reports a study on the effect of a hydrogen anneal after silicon pillar etch of surround-gate vertical MOSFETs intended for RF applications. A hydrogen anneal at 800 ?C is shown to give a 30% improvement in the drive current of 120-nm n-channel transistors compared with transistors without the hydrogen anneal. The value of drive current achieved is 250 ?A/?m, which is a record for thick pillar vertical MOSFETs. This improved performance is obtained even though a sacrificial oxidation was performed prior to the hydrogen anneal to smooth the pillar sidewall. The values of subthreshold slope and DIBL are 79 mV/decade and 45 mV/V, respectively, which are significantly better than most values reported in the literature for comparable devices. The H2 anneal is also shown to decrease the OFF-state leakage current by a factor of three

Easily measureable morpho-physiological traits as selection criteria for terminal drought tolerance in groundnut (Arachis hypogaea L.)

This study was conducted at El Obied Research Station Farm, North Kordofan State Sudan, with the objective of identifiying easily measurable morpho-physiolgical traits that could be used in drought tolerance breeding programs. Nine groundnut mutants together with three parents were evaluated under normal and terminal drought stress environments in 2003 and 2004 cropping seasons in a randomized complete block design with four replications. The genotypes did not differ significantly in the number of days to 75% emergence, with  a range of 6-8 days. Most of the measured traits showed higher values under normal than under stressed environments. Under stressed environment, some mutants like Barberton-B-30-3 and Barberton-B-30-4, exceeded their parents in pod yield (PY) /plant, dry matter production (DM) and leaf relative water content (LRWC), whereas they showed lower specific leaf area (SLA), canopy temperature (CT) and leaf senescence (LSENS) than their parents. CT, LRWC, LSENS and PY showed relatively medium broad-sense heritab-ility estimates under stress environment. PY was positively, significantly and genotypically correlated with DM and LRWC while significantly and negatively correlated with SLA, CT and LSENS under stress enviro-nment. Since these traits are reasonably heritable, strongly correlated with PY under stress enviroment and easily measurable under field conditions, they could be suggested as selection criteria for droguht tolerance in groundnut. The mutant Barberton-B-30-3, which produced the highest PY, DM and LRWC, under terminal drought stress, could be suggested as the best drought tolerant mutant in this study bending further testing over years and locations. &nbsp

Self-aligned silicidation of surround gate vertical MOSFETs for low cost RF applications

We report for the first time a CMOS-compatible silicidation technology for surround-gate vertical MOSFETs. The technology uses a double spacer comprising a polysilicon spacer for the surround gate and a nitride spacer for silicidation and is successfully integrated with a Fillet Local OXidation (FILOX) process, which thereby delivers low overlap capacitance and high drive-current vertical devices. Silicided 80-nm vertical n-channel devices fabricated using 0.5-?m lithography are compared with nonsilicided devices. A source–drain (S/D) activation anneal of 30 s at 1100 ?C is shown to deliver a channel length of 80 nm, and the silicidation gives a 60% improvement in drive current in comparison with nonsilicided devices. The silicided devices exhibit a subthreshold slope (S) of 87 mV/dec and a drain-induced barrier lowering (DIBL) of 80 mV/V, compared with 86 mV/dec and 60 mV/V for nonsilicided devices. S-parameter measurements on the 80-nm vertical nMOS devices give an fT of 20 GHz, which is approximately two times higher than expected for comparable lateral MOSFETs fabricated using the same 0.5-?m lithography. Issues associated with silicidation down the pillar sidewall are investigated by reducing the activation anneal time to bring the silicided region closer to the p-n junction at the top of the pillar. In this situation, nonlinear transistor turn-on is observed in drain-on-top operation and dramatically degraded drive current in source-on-top operation. This behavior is interpreted using mixed-mode simulations, which show that a Schottky contact is formed around the perimeter of the pillar when the silicided contact penetrates too close to the top S/D junction down the side of the pillar

Characterizing Dust-Radiation Feedback and Refining the Horizontal Resolution of the MarsWRF Model Down to 0.5 Degree

Acknowledgments Once again, our warmest thanks go to the PlanetWRF development team for providing the MarsWRF model free of charge to us and their proactive attitude in general. We would also like to thank two anonymous reviewers and the Associate Editor Dr Claire Newman for their several detailed and insightful comments and suggestions that helped to significantly improve the quality of the paper. We would like to acknowl- edge the support of this work by funding from the United Arab Emirates University (UAE University). Also, we are deeply grateful to High-Performance Computing, Division of Information Technology, UAE University, for the valuable access to the computational resources required for this work. We thank IT engineers Asma AlNeyadi, Anil Thomas, and Nithin Damodaran for their professional assistance and support in technical questions. M.-P. Z. has been partially funded by the AEI (MDM-2017-0737, Unity of Excellence “María de Maeztu” - Centro de Astro- biología (CSIC-INTA)) and the Spanish Ministry of Science and Innovation (PID2019-104205GB-C219). Finally, we declare that there are no real or perceived conflicts of interests for any author.Peer reviewedPublisher PD

Fully Interactive and Refined Resolution Simulations of the Martian Dust Cycle by the MarsWRF Model

Acknowledgments: First of all, our warmest thanks go to the PlanetWRF development team for providing the MarsWRF model free of charge to us and their proactive attitude in general. We thank Andy Heaps, National Centre for Atmospheric Science (NCAS), Department of Meteorology, University of Reading, UK, for his helpful advice regarding the data visualization using cf‐Python. We would also like to thank Michael Mischna, Alexandre Kling, and the Associate Editor Claire Newman for their several detailed and insightful comments and suggestions that helped to significantly improve the quality of the paper. M. P. Z. acknowledges the partial support by the Spanish State Research Agency (AEI) project MDM‐2017‐0737 Centro de Astrobiología (CSIC‐INTA), Unidad de Excelencia María de Maeztu. Internally, we would like to express our greatest thanks to the High‐Performance Computing, Division of Information Technology, United Arab Emirates University. Our particular thanks go to Asma AlNeyadi, Anil Thomas, and Nithin Damodaran for their intensive and continuous support in technically demanding questions. Also, we would like to thank the Digitization Unit, UAEU Libraries, for the digitization of auxiliary data on the observational record of the atmospheric T15 temperature and vertical weighting functions of Viking/IRTM. In addition, we thank UAEU Libraries for their assistance in making supporting data of this article available online. In particular, we are grateful to Digitization Technician Shireen M. Wolied, Fadl M. Musa/Digital Library Service, and Student Muhammad Abdul Rahim Sami Ullah. Funding Information: United Arab Emirates University (UAEU). Grant Number: 21R033‐NSS Center 7‐2017 Spanish State Research Agency (AEI). Grant Number: MDM‐2017‐0737Peer reviewedPublisher PD

Factors affecting engagement in web-based health care patient information: narrative review of the literature

BACKGROUND: Web-based content is rapidly becoming the primary source of health care information. There is a pressing need for web-based health care content to not only be accurate but also be engaging. Improved engagement of people with web-based health care content has the potential to inform as well as influence behavioral change to enable people to make better health care choices. The factors associated with better engagement with web-based health care content have previously not been considered. OBJECTIVE: The aims of this study are to identify the factors that affect engagement with web-based health care content and develop a framework to be considered when creating such content. METHODS: A comprehensive search of the PubMed and MEDLINE database was performed from January 1, 1946, to January 5, 2020. The reference lists of all included studies were also searched. The Medical Subject Headings database was used to derive the following keywords: "patient information," "online," "internet," "web," and "content." All studies in English pertaining to the factors affecting engagement in web-based health care patient information were included. No restrictions were set on the study type. Analysis of the themes arising from the results was performed using inductive content analysis. RESULTS: The search yielded 814 articles, of which 56 (6.9%) met our inclusion criteria. The studies ranged from observational and noncontrolled studies to quasi-experimental studies. Overall, there was significant heterogeneity in the types of interventions and outcome assessments, which made quantitative assessment difficult. Consensus among all authors of this study resulted in six categories that formed the basis of a framework to assess the factors affecting engagement in web-based health care content: easy to understand, support, adaptability, accessibility, visuals and content, and credibility and completeness. CONCLUSIONS: There is a paucity of high-quality data relating to the factors that improve the quality of engagement with web-based health care content. Our framework summarizes the reported studies, which may be useful to health care content creators. An evaluation of the utility of web-based content to engage users is of significant importance and may be accessible through tools such as the Net Promoter score. Web 3.0 technology and development of the field of psychographics for health care offer further potential for development. Future work may also involve improvement of the framework through a co-design process

Development of a dynamic dust source map for NMME-DREAM v1.0 model based on MODIS Normalized Difference Vegetation Index (NDVI) over the Arabian Peninsula

We developed a time-dependent dust source map for the NMME Dust Regional Atmospheric Model (DREAM v1.0) based on the satellite MODIS Normalized Difference Vegetation Index (NDVI). Areas with NDVI&thinsp;&lt;0.1 are classified as active dust sources. The updated modeling system is tested for dust emission capabilities over SW Asia using a mesoscale model grid increment of 0.1∘×0.1∘ for a period of 1 year (2016). Our results indicate significant deviations in simulated aerosol optical depths (AODs) compared to the static dust source approach and general increase in dust loads over the selected domain. Comparison with MODIS AOD indicates a more realistic spatial distribution of dust in the dynamic source simulations compared to the static dust sources approach. The modeled AOD bias is improved from −0.140 to 0.083 for the case of dust events (i.e., for AOD&thinsp;&gt;0.25) and from −0.933 to −0.424 for dust episodes with AOD&thinsp;&gt;1. This new development can be easily applied to other time periods, models, and different areas worldwide for a local fine tuning of the parameterization and assessment of its performance.</p