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2021

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Articles 1 - 30 of 24330

Full-Text Articles in Physical Sciences and Mathematics

Exposing And Fixing Causes Of Inconsistency And Nondeterminism In Clustering Implementations, Xin Yin Dec 2021

Exposing And Fixing Causes Of Inconsistency And Nondeterminism In Clustering Implementations, Xin Yin

Dissertations

Cluster analysis aka Clustering is used in myriad applications, including high-stakes domains, by millions of users. Clustering users should be able to assume that clustering implementations are correct, reliable, and for a given algorithm, interchangeable. Based on observations in a wide-range of real-world clustering implementations, this dissertation challenges the aforementioned assumptions.

This dissertation introduces an approach named SmokeOut that uses differential clustering to show that clustering implementations suffer from nondeterminism and inconsistency: on a given input dataset and using a given clustering algorithm, clustering outcomes and accuracy vary widely between (1) successive runs of the same toolkit, i.e., nondeterminism ...


Characterization Of The Ch Addition Product From Meta- And Ortho-Xylene + Ch Reaction And Direct Experimental Observation Of The Tetrabromine Cluster Br4 Using Synchrotron Photoionization Mass Spectrometry, Rory R. Mcclish Dec 2021

Characterization Of The Ch Addition Product From Meta- And Ortho-Xylene + Ch Reaction And Direct Experimental Observation Of The Tetrabromine Cluster Br4 Using Synchrotron Photoionization Mass Spectrometry, Rory R. Mcclish

Master's Theses

This thesis is centered on the use of a unique gas-phase spectroscopy technique to characterize products and elucidate reaction mechanisms. Experiments were carried out at the Chemical Dynamics Beamline 9.0.2 of the Advanced Light Source located at the Lawrence Berkeley National Laboratory in Berkeley, CA. Computational work was performed on the scientific supercomputer at USF to supplement experimental findings. Chapter 1 contextualizes the work spurred in response to the deleterious interactions of anthropogenic emissions on Earth’s climate. Chapter 2 describes the theoretical manipulations foundational to the experimental design and interpretation. Chapter 3 delves into the physical details ...


Model Checks For Two-Sample Location-Scale, Atefeh Javidialsaadi Dec 2021

Model Checks For Two-Sample Location-Scale, Atefeh Javidialsaadi

Dissertations

Two-sample location-scale refers to a model that permits a pair of standardized random variables to have a common distribution. This means that if X1 and X2 are two random variables with means µ1 and µ2 and standard deviations ?1 and ?2, then (X1 - µ1)/?1 and (X2 - µ2)/?2 have some common unspecified standard or base distribution F0. Function-based hypothesis testing for these models refers to formal tests that would help determine whether or not two samples may have come from some location-scale family of distributions, without specifying the standard distribution ...


Hydrophobically Modified Isosorbide Dimethacrylates As Biomaterials For Bisphenol A Free Dental Fillings, Bilal Marie Dec 2021

Hydrophobically Modified Isosorbide Dimethacrylates As Biomaterials For Bisphenol A Free Dental Fillings, Bilal Marie

Dissertations

Amalgam and Bisphenol A glycerolate dimethacrylate (BisGMA) are the main dental filling materials in use today. Because of the negative perception of amalgam and its lower esthetic appeal, as well as the desire to replace the endocrine disruptor Bisphenol A, which is the building block of BisGMA, there has been a critical need to search for safer alternatives to these dental filling materials.

Isosorbide is a sugar-based molecule generally recognized as safe. It has been extensively studied as a replacement to the Bisphenol A core in various materials. However, isosorbide is extremely hygroscopic, and water uptake in dental fillings causes ...


Coherent Control Of Dispersive Waves, Jimmie Adriazola Dec 2021

Coherent Control Of Dispersive Waves, Jimmie Adriazola

Dissertations

This dissertation addresses some of the various issues which can arise when posing and solving optimization problems constrained by dispersive physics. Considered here are four technologically relevant experiments, each having their own unique challenges and physical settings including ultra-cold quantum fluids trapped by an external field, paraxial light propagation through a gradient index of refraction, light propagation in periodic photonic crystals, and surface gravity water waves over shallow and variable seabeds. In each of these settings, the physics can be modeled by dispersive wave equations, and the technological objective is to design the external trapping fields or propagation media such ...


Private And Federated Deep Learning: System, Theory, And Applications For Social Good, Han Hu Dec 2021

Private And Federated Deep Learning: System, Theory, And Applications For Social Good, Han Hu

Dissertations

During the past decade, drug abuse continues to accelerate towards becoming the most severe public health problem in the United States. The ability to detect drug­abuse risk behavior at a population scale, such as among the population of Twitter users, can help to monitor the trend of drug­abuse incidents. However, traditional methods do not effectively detect drug­abuse risk behavior in tweets, mainly due to the sparsity of such tweets and the noisy nature of tweets. In the first part of this dissertation work, the task of classifying tweets as containing drug­abuse risk behavior or not, is ...


Parameter Estimation And Inference Of Spatial Autoregressive Model By Stochastic Gradient Descent, Gan Luan Dec 2021

Parameter Estimation And Inference Of Spatial Autoregressive Model By Stochastic Gradient Descent, Gan Luan

Dissertations

Stochastic gradient descent (SGD) is a popular iterative method for model parameter estimation in large-scale data and online learning settings since it goes through the data in only one pass. While SGD has been well studied for independent data, its application to spatially-correlated data largely remains unexplored. This dissertation develops SGD-based parameter estimation and statistical inference algorithms for the spatial autoregressive (SAR) model, a common model for spatial lattice data.

This research contains three parts. (I) The first part concerns SGD estimation and inference for the SAR mean regression model. A new SGD algorithm based on maximum likelihood estimator (MLE ...


Experimental And Computational Studies Of Functionalized Carbon Nanotubes For Use In Energy Storage Devices And Membranes, Emine S. Karaman Dec 2021

Experimental And Computational Studies Of Functionalized Carbon Nanotubes For Use In Energy Storage Devices And Membranes, Emine S. Karaman

Dissertations

Electrolytes with good interfacial stability are a crucial component of any electrochemical device. The development of novel gel polymer electrolytes (GEs) with good interface stability and better manufacturability is important for the development of the next generation electrochemical devices. Gel electrolytes are hybrid electrolyte materials, combining benefits of both liquid and solid systems. Compared with liquid and solid electrolytes, GEs open new design opportunities and do not require rigorous encapsulation methods. In this dissertation, studies on functionalized carbon nanotubes (fCNTs) and graphene oxide (GO) doped polyvinyl alcohol (PVA) based gel electrolytes (GEs) are reported. The ionic conductivity and mechanical strength ...


On Performance Optimization And Prediction Of Parallel Computing Frameworks In Big Data Systems, Haifa Alquwaiee Dec 2021

On Performance Optimization And Prediction Of Parallel Computing Frameworks In Big Data Systems, Haifa Alquwaiee

Dissertations

A wide spectrum of big data applications in science, engineering, and industry generate large datasets, which must be managed and processed in a timely and reliable manner for knowledge discovery. These tasks are now commonly executed in big data computing systems exemplified by Hadoop based on parallel processing and distributed storage and management. For example, many companies and research institutions have developed and deployed big data systems on top of NoSQL databases such as HBase and MongoDB, and parallel computing frameworks such as MapReduce and Spark, to ensure timely data analyses and efficient result delivery for decision making and business ...


A Practical Approach To Automated Software Correctness Enhancement, Aleksandr Zakharchenko Dec 2021

A Practical Approach To Automated Software Correctness Enhancement, Aleksandr Zakharchenko

Dissertations

To repair an incorrect program does not mean to make it correct; it only means to make it more-correct, in some sense, than it is. In the absence of a concept of relative correctness, i.e. the property of a program to be more-correct than another with respect to a specification, the discipline of program repair has resorted to various approximations of absolute (traditional) correctness, with varying degrees of success. This shortcoming is concealed by the fact that most program repair tools are tested on basic cases, whence making them absolutely correct is not clearly distinguishable from making them relatively ...


Usf Jamovi Tutorial Project: Open Education Resource, Aline Hitti, Saera Khan Dec 2021

Usf Jamovi Tutorial Project: Open Education Resource, Aline Hitti, Saera Khan

USF OER Faculty Grant

Jamovi is an open source free software that USF staff, faculty and student can download to carry out any statistical analyses. The current report summarizes the progress made on an Open Education Resource Grant funded project, which aimed to created Jamovi tutorials. In this report, student feedback and faculty reaction are summarized after one semester of using the tutorials created.


Long Term Observation Of The Grassland Vegetation Used Intensively Or Extensively And Ecologically, H.-D. Matthes, J. Matthes, W. Jentsch, V. Pastushenko Dec 2021

Long Term Observation Of The Grassland Vegetation Used Intensively Or Extensively And Ecologically, H.-D. Matthes, J. Matthes, W. Jentsch, V. Pastushenko

International Grassland Congress Proceedings

The aim of the present paper was to study alterations of the grassland flora from 55 plots following a more extensive management under long term observation within 6 years. Extensification of grassland use leads to an increase of the numbers of plant species by 32%, “Red-list-species” included. The moisture number of the soils slightly increased and the reaction and nitrogen numbers decreased. Results are presented for different vegetation units.


Influence Of Extensive Management On Botanical Composition Of Permanent Meadow Sward, K. Mlynarczyk, E. Korona, E. Marks Dec 2021

Influence Of Extensive Management On Botanical Composition Of Permanent Meadow Sward, K. Mlynarczyk, E. Korona, E. Marks

International Grassland Congress Proceedings

The aim of undertaken investigations was to find the possibilities of grassland management with special respect to the biodiversity and the landscape conservation. Changes in botanical composition of the meadow sward against a background of different mowing utilization were examined on the semi-natural meadows situated on the peat-mursh soil in Masurian Landscape Park (north-east Poland). The areas mown with biennial pause and completely turned off from uses followed gradual simplifying of species composition and increasing of bog species participation. Results show on advisability of passing one harvest each year or with one-year pauses.


Vegetation Changes In Sown Grassland In The Uk After Nine Years Of Extensive Grazing Management, C. A. Marriott, G. T. Barthram Dec 2021

Vegetation Changes In Sown Grassland In The Uk After Nine Years Of Extensive Grazing Management, C. A. Marriott, G. T. Barthram

International Grassland Congress Proceedings

The effect of extensive grazing management with sheep on vegetation change in sown pastures (initially containing Lolium perenne and Trifolium repens) in the uplands of Scotland was investigated from 1990-1999. One treatment was representative of current more intensive management systems; it was fertilized, and maintained at a sward surface height of 4 cm. Two treatments were unfertilized and were maintained at sward surface heights of 4 cm or 8 cm; the ewe numbers carried on these treatments averaged 74% and 44%, respectively, of those on the fertilized treatment. In all treatments the sheep were Scottish Blackface ewes. Their single lambs ...


The Influence Of Rising Atmospheric Co2 On Grassland Ecosystems, J. A. Morgan, P. C. D. Newton, J. Nösberger, C. E. Owensby Dec 2021

The Influence Of Rising Atmospheric Co2 On Grassland Ecosystems, J. A. Morgan, P. C. D. Newton, J. Nösberger, C. E. Owensby

International Grassland Congress Proceedings

Increasing atmospheric CO2 concentrations and climatic change will have significant effects on the ecology of grasslands. This paper evaluates results from four CO2 enrichment studies in contrasting grasslands. A Swiss study investigates the effects of elevated CO2 (600 μL L-1 CO2) on perennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens L), a New Zealand study examines how elevated CO2 (475 μL L-1 CO2) affects a botanically diverse pasture, and studies in the Kansas tallgrass prairie and the Colorado shortgrass steppe investigate the effects of an approximate doubling of CO2 ...


A Novel Arabic Corpus For Text Classification Using Deep Learning And Word Embedding, Roua A. Abou Khachfeh, Islam El Kabani, Ziad Osman Dec 2021

A Novel Arabic Corpus For Text Classification Using Deep Learning And Word Embedding, Roua A. Abou Khachfeh, Islam El Kabani, Ziad Osman

BAU Journal - Science and Technology

Over the last years, Natural Language Processing (NLP) for Arabic language has obtained increasing importance due to the massive textual information available online in an unstructured text format, and its capability in facilitating and making information retrieval easier. One of the widely used NLP task is “Text Classification”. Its goal is to employ machine learning technics to automatically classify the text documents into one or more predefined categories. An important step in machine learning is to find suitable and large data for training and testing an algorithm. Moreover, Deep Learning (DL), the trending machine learning research, requires a lot of ...


A Poisson-Akash Inrar(1) Model For Over Dispersed Count Time Series, Emmanuel W. Okereke, Sunday N. Gideon Dec 2021

A Poisson-Akash Inrar(1) Model For Over Dispersed Count Time Series, Emmanuel W. Okereke, Sunday N. Gideon

BAU Journal - Science and Technology

In this paper, a Poisson-Akash INAR(1) model was proposed in order to improve on the modelling of overdispersed stationary count time series. The estimators of the parameters of the model were derived using the Yule-Walker (YW) method and the conditional least squares (CLS) method. An expression for the conditional log-likelihood and the r-step ahead forecast were obtained for the model. Three overdispersed nonseasonal stationary count time series were modelled to illustrate the applicability of the proposed model as well as its capacity to outperform the competing INAR (1) models in modelling overdispersed stationary count time series and the result ...


Walking Diagonally: A Simple Proof Of Countability Of The Set Of All Finite Subsets Of Naturals, Miroslav Kures Dec 2021

Walking Diagonally: A Simple Proof Of Countability Of The Set Of All Finite Subsets Of Naturals, Miroslav Kures

BAU Journal - Science and Technology

The countability of the set of finite subsets of natural numbers is derived. In addition to the derivation itself, the use of diagonal method is illustratively presented; thinking about infinite sets relate to the name of Georg Ferdinand Ludwig Philipp Cantor, the creator of set theory, which has become a fundamental theory in mathematics. The proof of the claim is original, although the theorem is an analogy with the famous theorem about the countability of rational numbers. A certain insight into the subsets of natural numbers is given. Anyway, the technique could be considered already at high school level as ...


Role Of Technological Revolution In Transport And Communications Development, Mohamad B. Chami Dec 2021

Role Of Technological Revolution In Transport And Communications Development, Mohamad B. Chami

BAU Journal - Science and Technology

The arousal of technology has changed a lot of aspects in human life and has drastically changed its path through a revolution that changed the whole world. This revolution took place in various aspects while affecting significantly the global economy and from those fields that considerably affect the life of human beings in the previous and current centuries are Information and Communication Technology (ICT) and transportation. It is these two factors that play a major role in the economy of countries and dominate the lives of societies in the world. Thus, this paper studies the impact of the technology revolution ...


The Inhibition Activity Of Tert-Butylhydroquinone Towards Corrosion Of Aluminum, Copper And Stainless Steel In Biodiesel Blend B20 Alternative Fuel, Chaza Joumaa, Ibtissam Saad, Ghassan Younes Dec 2021

The Inhibition Activity Of Tert-Butylhydroquinone Towards Corrosion Of Aluminum, Copper And Stainless Steel In Biodiesel Blend B20 Alternative Fuel, Chaza Joumaa, Ibtissam Saad, Ghassan Younes

BAU Journal - Science and Technology

Tert-butylhydroquinone (TBHQ) has been investigated as corrosion inhibitor for aluminum; copper and stainless steel in biodiesel blend B20 by using electrochemical impedance spectroscopy (EIS) method. The results showed that the inhibition efficiency increases with an increase in the concentration of TBHQ but decreases with increasing temperature from 30℃ to 60℃. A maximum inhibition efficiency of about 61.52% for aluminum was recorded for THBQ in biodiesel blend B20 at temperature 30℃ and at a concentration of 4x10-6 M which is the lowest concentration used compared to the concentrations of TBHQ used for the other metals (copper and stainless steel ...


Physical And Magnetic Properties Of Nanosized Mn0.5ni0.5¬Fe2-Xprxo4 Prepared By Co-Precipitation Method, Douaa El-Said Bakeer, Khulud Habanjar, Ghassan Youness, Mohammad Abou Ghoush Dec 2021

Physical And Magnetic Properties Of Nanosized Mn0.5ni0.5¬Fe2-Xprxo4 Prepared By Co-Precipitation Method, Douaa El-Said Bakeer, Khulud Habanjar, Ghassan Youness, Mohammad Abou Ghoush

BAU Journal - Science and Technology

Nanosized Mn0.5Ni0.5Fe2-xPrxO4, x=0.0, 0.02, 0.04, 0.06, 0.08, 0.1 and 0.15 are prepared by co-precipitation method at calcination temperature 650oC for 4 hours. X-ray diffraction patterns show the presence of the cubic (Mn-Ni)- ferrite phase and anti-ferromagnetic a-Fe2O3. The variation in the lattice parameter “a” is due to the replacement of smaller radius ions Fe+3 by larger radius ions Pr+3. Transmission electron micrographs indicate that the particles are spherical in shape. The moderately agglomerated particles ...


Elevated Co2 Enhances Productivity And The C/N Ratio Of Grasses In The Colorado Shortgrass Steppe, J. A. Morgan, A. R. Mosier, D. R. Lecain, W. J. Parton, D. G. Milchunas Dec 2021

Elevated Co2 Enhances Productivity And The C/N Ratio Of Grasses In The Colorado Shortgrass Steppe, J. A. Morgan, A. R. Mosier, D. R. Lecain, W. J. Parton, D. G. Milchunas

International Grassland Congress Proceedings

Atmospheric CO2 concentrations have been increasing since the industrial revolution, and are projected to double within this century over today's concentration of 360 µmol mol-1 . This study used six open-top chambers in the Colorado, USA shortgrass steppe to investigate how increasing CO2 will affect productivity and C and N status of indigenous perennial grasses and forbs. From March until October, chambers were placed on two plots in each of the three blocks. In each block, one chamber was assigned an ambient CO2 treatment (~360 µmol mol-1), the other an elevated CO2 treatment (~720 ...


Rangeland Desertification In China, Wang Tao Dec 2021

Rangeland Desertification In China, Wang Tao

International Grassland Congress Proceedings

Land desertification is one of the most serious environmental and social-economic problems in the North China. The processes of desertification mainly have being controlled by the interaction of human activities and fragile eco-environment, that means the pattern and intension of landuse are major factors for development or reverse of desertification. Because of the increasing pressure of population, the rangeland in the North China has being cultivated decade by decade, which changed landuse from grassing to cropping in a large area and destroyed the natural vegetation cover. The result is to let the wind erosion become easier and the desertification has ...


Grasslands, Communicating The Benefits, D. Keeney Dec 2021

Grasslands, Communicating The Benefits, D. Keeney

International Grassland Congress Proceedings

The multiple benefits of perennial agriculture , including forages and grasslands, for building soil quality, protection of natural resources, enhancement of biodiversity and wildlife, are well known to us, but little understood by the public. This is not a situation where “more education” would necessarily increase recognition. Rather, we must build in the public a desire for the enhancement of green space, clean water and air, and diverse landscapes that multiple purpose agriculture can bring. We seek such environments intuitively and now that much of the world’s people are “trapped” in urban settings of steel and concrete, this desire is ...


Silver Bow Creek/Butte Area Npl Site, Trec Inc., A Woodard And Curran Company Dec 2021

Silver Bow Creek/Butte Area Npl Site, Trec Inc., A Woodard And Curran Company

Silver Bow Creek/Butte Area Superfund Site

No abstract provided.


Silver Bow Creek/Butte Area Npl Site, Trec Inc., A Woodard And Curran Company Dec 2021

Silver Bow Creek/Butte Area Npl Site, Trec Inc., A Woodard And Curran Company

Silver Bow Creek/Butte Area Superfund Site

No abstract provided.


Silver Bow Creek Butte Area Npl Site 2022 Draft Butte Priority Soils Operable Unit Interim Site-Wide Groundwater Monitoring Qapp. Consent Decree- Civil Action No. Cv 89-039-Bu-She, Josh Bryson Dec 2021

Silver Bow Creek Butte Area Npl Site 2022 Draft Butte Priority Soils Operable Unit Interim Site-Wide Groundwater Monitoring Qapp. Consent Decree- Civil Action No. Cv 89-039-Bu-She, Josh Bryson

Silver Bow Creek/Butte Area Superfund Site

No abstract provided.


Silver Bow Creek/Butte Area Npl Site 2022 Draft Butte Priority Soils Operable Unit Interim Site-Wide Groundwater Monitoring Quality Assurance Project Plan (Qapp), 11/16/21, Nikia Greene Dec 2021

Silver Bow Creek/Butte Area Npl Site 2022 Draft Butte Priority Soils Operable Unit Interim Site-Wide Groundwater Monitoring Quality Assurance Project Plan (Qapp), 11/16/21, Nikia Greene

Silver Bow Creek/Butte Area Superfund Site

No abstract provided.


Self-Assembly Of Black Cumin Oil-Based Nanoemulsion On Various Surfactants: A Molecular Dynamics Study, Aulia Fikri Hidayat, Taufik Muhammad Fakih Dec 2021

Self-Assembly Of Black Cumin Oil-Based Nanoemulsion On Various Surfactants: A Molecular Dynamics Study, Aulia Fikri Hidayat, Taufik Muhammad Fakih

Makara Journal of Science

Black cumin is commonly used as traditional medicine due to its wide range of pharmacological potential. Black cumin oil (BCO) was often prepared as nanoemulsion to improve its solubility, stability, and bioavailability. This study was conducted to investigate the molecular behavior as well as structural evolution of BCO-surfactant systems during self-assembly micellization using molecular dynamics (MD) simulations. Several BCO constituents and variations of surfactants were employed to model BCO-surfactant systems. 50 ns of MD simulations were performed to elucidate their evolution of structures and physicochemical properties during formation. Results showed that BCO-tween20 and BCO-lecithin were able to form spherical-shaped micelles ...


Magnetically Separable Fe3o4/Sio2/Tio2 Photocatalyst Composites Prepared Through Hetero Agglomeration For The Photocatalytic Degradation Of Paraquat, Jarnuzi Gunlazuardi, Adel Fisli, Ridwan Ridwan, Yuni Krisyuningsih Krisnandi, Didier Robert Dec 2021

Magnetically Separable Fe3o4/Sio2/Tio2 Photocatalyst Composites Prepared Through Hetero Agglomeration For The Photocatalytic Degradation Of Paraquat, Jarnuzi Gunlazuardi, Adel Fisli, Ridwan Ridwan, Yuni Krisyuningsih Krisnandi, Didier Robert

Makara Journal of Science

A photocatalyst supported on magnetic material allows the simple technique by using an external magnetic material to separate photocatalyst from the treated water. Thus, it is a magnetically separable nanoparticles photocatalyst (MSNP). The use of superparamagnetic nanoparticles that do not pose spontaneous magnetic moment thus could be dispersed in water and can be recollected easily by an external magnetic bar. We prepare Fe3O4/SiO2/TiO2 composite by hetero agglomeration of Fe3O4/SiO2 and TiO2 at a pH range of 3 to 6.2 in an aqueous slurry.The Fe3 ...