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Full-Text Articles in Engineering

Matlab Modeling Of Ofdm Modulation Technique Across A 24 Khz, 48 Khz, And 3 Mhz Bandwidth In The High-Frequency Radio Band (3-30) Mhz, Josiah Myer, Tyler Collins, Sarah Taylor, Natalia Anglero Jan 2021

Matlab Modeling Of Ofdm Modulation Technique Across A 24 Khz, 48 Khz, And 3 Mhz Bandwidth In The High-Frequency Radio Band (3-30) Mhz, Josiah Myer, Tyler Collins, Sarah Taylor, Natalia Anglero

Faculty-Sponsored Student Research & Capstones

The goal of this project is to use MATLAB to model orthogonal frequency division multiplexing (OFDM) modulation technique across 24 kHz, 48 kHz, and 3 MHz bandwidths in the high frequency (HF) radio band (3-30 MHz). The purpose of our design is to make HF long distance communication faster and more reliable so that every part of the world, including the most remote parts, will have access to high speed, long distance wireless communication. Our MATLAB model will allow us to modify the bandwidth, carrier frequency, modulation type, signal to noise ratio (SNR), and image size to determine which combination …

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Observation Of New Particle Formation In The Northern Hemisphere At Altitude From 4 To 20 Km, Mohamed Saad Jan 2021

Observation Of New Particle Formation In The Northern Hemisphere At Altitude From 4 To 20 Km, Mohamed Saad

Electronic Theses and Dissertations

New particle formation (NPF) is investigated using measurements of aerosol size distributions and meteorological variables made in two continents, including USA and Europe. Despite the considerably different aerosol particle abundances among the sites, a common relationship was found between the characteristics of NPF events and the air mass convective and/or advective transport. CO and O3 act as tracers of tropospheric and stratospheric air, respectively, their statistical relationship can be used to quantify air mass characteristics and origins. The mixing ratio values of CO increased within the upper troposphere layer before/during NPF events, which may serve as an indicator of occurring …

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Renewable Energy Production By Solar Chimney: The Influence Of Curved Guide Vanes On The Performance Of A Solar Chimney Using Cfd Simulation, Haokun Xue Jan 2021

Renewable Energy Production By Solar Chimney: The Influence Of Curved Guide Vanes On The Performance Of A Solar Chimney Using Cfd Simulation, Haokun Xue

Theses, Dissertations and Capstones

The aim of this study is to investigate the effect of the guide vanes on the efficiency of the turbine of solar chimney power plant using Computational Fluid Dynamics (CFD). In this study, a 3-Dimentional CFD simulation of solar chimney power plant based on the Manzanares prototype is performed. The CFD simulation is validated by comparing the experimental data from the Manzanares prototype and simulation data with both 2D and 3D cases. To capture turbulent flow inside the chimney, the SST 𝑘 − 𝜔 turbulence model is used. The first object is to investigate the flow performance under the influence …

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To What Extent Can Innovative International Project Delivery Strategies (Which Leverage Bim) Improve The Cost Certainty Of Large Complex Public Procurement Projects In The Context Of Irish Public Procurement?, Bim Tudublin, Roqaya Abouklaib Jan 2021

To What Extent Can Innovative International Project Delivery Strategies (Which Leverage Bim) Improve The Cost Certainty Of Large Complex Public Procurement Projects In The Context Of Irish Public Procurement?, Bim Tudublin, Roqaya Abouklaib

Capstone Reports

Cost overrun is one of the biggest issues in the construction sector, and cost certainty is one of the main aims of the public construction sector in Ireland. Studies have shown that multi-disciplinary collaboration will benefit a construction project throughout its lifecycle. BIM, Lean, and IPD are independent methodologies that encourage collaborative work, and there are existent effective synergies among these concepts. The synergetic innovative international strategies were utilised for delivering large complex projects successfully globally, and many authors have studied large complex public projects that have adopted innovative international project delivery strategies collaboratively and have shown that the cost …

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Identifying Sources Of Covid19 Pandemic Supply Chain Fragility, Clovia Hamilton Jan 2021

Identifying Sources Of Covid19 Pandemic Supply Chain Fragility, Clovia Hamilton

Technology & Society Faculty Publications

Supply chain management is in the industrial engineering management and operations management disciplines. It involves product procurement of raw materials, production, storage, distribution, wholesales, and retail sales. The COVID19 pandemic has the added challenge of healthcare service operations management. This paper is a bibliometric study of the COVID19 supply chain fragility problem. In February 2021, the United States’ President called for a review of the pandemic related supply chain for vaccines, personal protective equipment (PPE), medical equipment such as ventilators, and food. This study involves a search for references published between January 1, 2020 and April 30, 2021. It reveals …

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Off-Grid Energy System To Empower The People Of El Chorro In Peru, Henry Baldwin, Moon Cheong, Jenny Kane, Sofia Maeztu, Skylar Widman Jan 2021

Off-Grid Energy System To Empower The People Of El Chorro In Peru, Henry Baldwin, Moon Cheong, Jenny Kane, Sofia Maeztu, Skylar Widman

ENGS 89/90 Reports

Significance & Objectives: In 2006, more than six million people living in rural regions of Peru lacked access to electricity, resulting in a lower quality of life, limited educational opportunities, difficult means of communication, and worsened healthcare. Furthermore, the use of kerosene lamps and candles exacerbates respiratory illnesses, and dimmed lights can cause unnecessary eye strain with long term consequences. While the traditional strategy for increasing access to electricity is based around expanding the national electric grid, the complex terrain and remote location of many rural communities in Peru make this infeasible. In conjunction with WindAid, our goal is to …

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Laser Powder Bed Fusion Of Ti6al4v-Xcu: Process Parameters, Thywill Ccphas Dzogbewu Jan 2021

Laser Powder Bed Fusion Of Ti6al4v-Xcu: Process Parameters, Thywill Ccphas Dzogbewu

Journal of Metals, Materials and Minerals

The original intent of coating biomedical and surgical devices surface with antibacterial agents is to prevent infections. However, the difference in the material properties between the biomedical devices and the coating materials causes the coating material to spall from the biomedical devices. To address the situation, the current research focused on investigating the possibility of using laser powder bed fusion process a subset of additive manufacturing technology to in situ alloy 1 at% Cu with Ti6Al4V. In situ alloying 1 at% Cu with Ti6Al4V would lead to the production of medical and surgical devices with inbuilt antibacterial property. To determine …

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Integrating The Humanities With Engineering Through A Global Case Study Course, Kirsten A. Davis, Siddhant S. Joshi, Lori Czerwionka, Francisco Montalvo, Gabriel O. Rios-Rojas, Joe Tort, Jennifer Marston William, E. Nauman Jan 2021

Integrating The Humanities With Engineering Through A Global Case Study Course, Kirsten A. Davis, Siddhant S. Joshi, Lori Czerwionka, Francisco Montalvo, Gabriel O. Rios-Rojas, Joe Tort, Jennifer Marston William, E. Nauman

Journal of International Engineering Education

As the world becomes more connected and globalized, the problems that engineers are called upon to solve are increasingly complex and interdependent. Unfortunately, engineering coursework has traditionally focused on abstract and closed-ended problem solving, offering few opportunities for students to develop these skills. In this practice paper, we argue for the importance of integrating the humanities and engineering to understand the multiple and intersecting layers of context in an engineering project. We then describe the Humanities-Informed Engineering Projects course, which we developed to help students acquire this perspective. The course was piloted in Spring 2021 in response to the obstacles …

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Hyperspectral Empirical Absolute Calibration Model Using Libya 4 Pseudo-Invariant Calibration Site, Manisha Das Chaity Jan 2021

Hyperspectral Empirical Absolute Calibration Model Using Libya 4 Pseudo-Invariant Calibration Site, Manisha Das Chaity

Electronic Theses and Dissertations

The objective of this paper is to find an empirical hyperspectral absolute calibration model using Libya 4 pseudo-invariant calibration site (PICS). The approach involves using the Landsat 8 (L8) Operational Land Imager (OLI) as the reference radiometer and using Earth Observing One (EO-1) Hyperion, with a spectral resolution of 10 nm as a hyperspectral source. This model utilizes data from a region of interest (ROI) in an “optimal region” of 3% temporal, spatial, and spectral stability within the Libya 4 PICS. It uses an improved, simple, empirical, hyperspectral Bidirectional Reflectance Distribution function (BRDF) model accounting for four angles: solar zenith …

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A Study Of Geographic Information System-Based Watershed Processing For Hydrologic Analysis Of Ungauged Watersheds, Philip Adanbe Adalikwu Jan 2021

A Study Of Geographic Information System-Based Watershed Processing For Hydrologic Analysis Of Ungauged Watersheds, Philip Adanbe Adalikwu

Electronic Theses and Dissertations

The increasing application of geographic information system (GIS) technology in watershed modeling makes is necessary to further evaluate its impacts on runoff characteristics as a basis for improved hydrologic analysis in ungauged watersheds. Experts in the field of water resources and hydrology have recommended the practice of subdivision when modeling a watershed, and the use of observed data from hydrologically similar watershed to calibrate and validate an ungauged watershed’s model. However, previous studies have failed to adequately address the issues of watershed heterogeneity, spatial and temporal variability in physical parameters, GIS data resolution issues, including artifacts in automated extraction of …

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Extended Pseudo Invariant Calibration Site-Based Trend-To-Trend Cross-Calibration Of Optical Satellite Sensors, Prathana Khakurel Jan 2021

Extended Pseudo Invariant Calibration Site-Based Trend-To-Trend Cross-Calibration Of Optical Satellite Sensors, Prathana Khakurel

Electronic Theses and Dissertations

Satellite sensors have been extremely useful and are in massive demand in the understanding of the Earth’s surface and monitoring of changes. For quantitative analysis and acquiring consistent measurements, absolute radiometric calibration is necessary. The most common vicarious approach of radiometric calibration is cross-calibration, which helps to tie all the sensors to a common radiometric scale for consistent measurement. One of the traditional methods of cross-calibration is performed using temporally and spectrally stable pseudo-invariant calibration sites (PICS). This technique is limited by adequate cloud-free acquisitions for cross-calibration which would require a longer time to study the differences in sensor measurements. …

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Detection Of Change Points In Pseudo-Invariant Calibration Sites Time Series Using Multi-Sensor Satellite Imagery, Neha Khadka Jan 2021

Detection Of Change Points In Pseudo-Invariant Calibration Sites Time Series Using Multi-Sensor Satellite Imagery, Neha Khadka

Electronic Theses and Dissertations

The remote sensing community has extensively used Pseudo-Invariant Calibration Sites (PICS) to monitor the long-term in-flight radiometric calibration of Earth-observing satellites. The use of the PICS has an underlying assumption that these sites are invariant over time. However, the site’s temporal stability has not been assured in the past. This work evaluates the temporal stability of PICS by not only detecting the trend but also locating significant shifts (change points) lying behind the time series. A single time series was formed using the virtual constellation approach in which multiple sensors data were combined for each site to achieve denser temporal …

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A Hydrologic Climate Study For An Arid Region, Ali Alsubeai Jan 2021

A Hydrologic Climate Study For An Arid Region, Ali Alsubeai

Electronic Theses and Dissertations

Water is the most precious natural resource in arid regions due to the limitation of water resources, expanding population, and increasing volumes of industrial and domestic waste. The purpose of this research was to evaluate methods to estimate water quantity in an arid region. The research consisted of three separate studies. In the first study, hydrologic models used to estimate water quantity were evaluated for suitability of use in arid regions. Most hydrologic models that have been used in arid regions were originally developed for humid regions. Rainfall events in arid regions can be characterized as short-term, high intense rainstorms …

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An Integrated View Of Knowledge Management Enablers, Components, And Benefits: Comprehensive Literature Review, Shuaibu Hassan Usman, Jigish Zaveri, Aminu Hamza Jan 2021

An Integrated View Of Knowledge Management Enablers, Components, And Benefits: Comprehensive Literature Review, Shuaibu Hassan Usman, Jigish Zaveri, Aminu Hamza

Journal of International Technology and Information Management

The key to success in the 21st century, knowledge-based economy, will be the effective and efficient management of knowledge. Knowledge Management (KM) has a direct impact on organizational success. KM in a knowledge-based economy entails growth, value, and improving living standards through knowledge creation, storage, and dissemination. This study aims to integrate KM enablers, components, and benefits into a single view through a comprehensive literature search. The integrative view of these three factors would facilitate the understanding of KM initiatives within organizations. This paper performs a comprehensive literature review to explain the KM enablers, components, and benefits. From the …

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Moderate Heat-Assisted Gene Electrotransfer For Cutaneous Delivery Of A Dna Vaccine Against Hepatitis B Virus, Chelsea Edelblute, Cathryn Mangiamele, Richard Heller Jan 2021

Moderate Heat-Assisted Gene Electrotransfer For Cutaneous Delivery Of A Dna Vaccine Against Hepatitis B Virus, Chelsea Edelblute, Cathryn Mangiamele, Richard Heller

Bioelectrics Publications

An estimated 350 million people are living with chronic Hepatitis B virus (HBV) worldwide. Preventative HBV vaccination in infants has reduced the disease burden; however, insufficient immunization programs and access obstacles leave vulnerable populations at risk for infection in endemic regions. Gene electrotransfer (GET) using a noninvasive multielectrode array (MEA) provides an alternative platform for DNA vaccination in the skin. DNA vaccines are nonlive and nonreplicating and temperature stable unlike their counterparts. In addition, their simple engineering allows them to be manufactured quickly at a low cost. In the current work, we present the combination of GET and moderate heating …

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Studies On Protein Solubility, Ke Li Jan 2021

Studies On Protein Solubility, Ke Li

Doctoral Dissertations

"Solubility is a critical factor of protein-based drugs during processing and patient administration. This study focused on two aspects of solubility: one was the poly (ethylene) glycol (PEG) precipitation of monoclonal antibodies (mAbs) and another was crystallins aggregation that is associated with cataracts. Protein precipitation by PEG is a common technique for downstream processing. The effects of pH, ionic strength and the exclude volume effect on the protein precipitation by PEG were extensively studied, but the effects of glycosylation on protein precipitation by PEG has not been examined. Protein aggregation is not only a problem in downstream processing, but it …

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The Need For Aerospace Structural Health Monitoring: A Review Of Aircraft Fatigue Accidents, Luke Pollock, Ayah Khalid Abdelwahab, John Murray, Graham Wild Jan 2021

The Need For Aerospace Structural Health Monitoring: A Review Of Aircraft Fatigue Accidents, Luke Pollock, Ayah Khalid Abdelwahab, John Murray, Graham Wild

Research outputs 2014 to 2021

Aircraft accidents involving catastrophic fatigue failure have the potential for significant loss of life. The aim of this research was to investigate trends in aircraft fatigue failure accidents to inform aerospace Structural Health Monitoring (SHM) system Research and Development (R&D). The research involved collecting 139 aircraft fatigue failure accident reports from the Aviation Safety Network database, which were coded using a directed content analysis. The trends and features of the categorical data were then explored using an ex-post facto study. The results showed that fatigue failure accidents have increased at a rate of (3.4 ± 0.6)×10-2 per year since the …

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Quantification Of Climate Variability And Extreme Events In The Great Plains, Angelinah Ntsieng Rasoeu Jan 2021

Quantification Of Climate Variability And Extreme Events In The Great Plains, Angelinah Ntsieng Rasoeu

Electronic Theses and Dissertations

Climate variability and extreme events continue to worsen resulting in significant impacts to society and the environment. Quantifying precipitation variability, streamflow, and extreme events at local scale is crucial for local planning and management due to spatial and temporal precipitation variability which influences streamflow and thus, water resources. This study uses statistical tools to analyze 1895-2019 (125 years) of historical precipitation data to examine how long-term precipitation varies annually, seasonally, and monthly, and create climate classifications. The results show that annual precipitation is increasing linearly over time ranging from 13.2 in (1976) to 43.1 in (2010) and 5 climate classes …

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Human Activity Recognition Based On Wearable Flex Sensor And Pulse Sensor, Xiaozhu Jin Jan 2021

Human Activity Recognition Based On Wearable Flex Sensor And Pulse Sensor, Xiaozhu Jin

Electronic Theses and Dissertations

In order to fulfill the needs of everyday monitoring for healthcare and emergency advice, many HAR systems have been designed [1]. Based on the healthcare purpose, these systems can be implanted into an astronaut’s spacesuit to provide necessary life movement monitoring and healthcare suggestions. Most of these systems use acceleration data-based data record as human activity representation [2,3]. But this data attribute approach has a limitation that makes it impossible to be used as an activity monitoring system for astronavigation. Because an accelerometer senses acceleration by distinguishing acceleration data based on the earth’s gravity offset [4], the accelerometer cannot read …

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Classification And Evaluation Of Extended Pics (Epics) On A Global Scale For Calibration And Stability Monitoring Of Optical Satellite Sensors, Juliana Maria Fajardo Rueda Jan 2021

Classification And Evaluation Of Extended Pics (Epics) On A Global Scale For Calibration And Stability Monitoring Of Optical Satellite Sensors, Juliana Maria Fajardo Rueda

Electronic Theses and Dissertations

As targets for the calibration and monitoring of optical satellite sensors, historically stable areas across North Africa have been used, known as Pseudo Invariant Calibration Sites PICS. However, two major drawbacks exist for these sites; first is the dependency on a single location to be always invariant, and second is the limited amount of observation achieved using these sites. As a result, longer time periods are needed to construct a dense data set to assess the radiometric performance of on-orbit optical sensors, and be convinced that the change detected is sensor-specific rather than site-specific. This work presents a global land …

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Intercomparisons Of Three Global Bottom-Up Anthropogenic Emission Inventories: Implications For Air Quality, Halima Salah Jan 2021

Intercomparisons Of Three Global Bottom-Up Anthropogenic Emission Inventories: Implications For Air Quality, Halima Salah

Wayne State University Theses

Air pollution from human activities plays an important role in affecting ambient air quality, climate change and human health. To provide changes in global environmental policies to reduce air pollution, emission inventories are critical as they aide in the understanding of air quality impacts across multiple scales. The state-of-the-science global bottom-up anthropogenic emission inventories are the Evaluating the Climate and Air Quality Impacts of Short-Lived Pollutants version 6b (ECLIPSEv6b) for emissions from 1990-2050, Emission Database for Global Atmospheric Research version 5.0 (EDGARv5) for emissions from 1970-2015, and the Community Emissions Data System that was released in April 2021 (CEDS) for …

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Fractal Graphene Patch Antennas And The Thz Communications Revolution, Jonathan Blackledge, A. Boretti, L. Rosa, S. Castelletto Jan 2021

Fractal Graphene Patch Antennas And The Thz Communications Revolution, Jonathan Blackledge, A. Boretti, L. Rosa, S. Castelletto

Conference papers

Fractal antennas have and are continuing to receive attention in regard to the futureof wireless communications. This is because of their wide- and multi-band capabilities, theopportunity of fractal geometries to drive multiple resonances, and, the ability to make smallerand lighter antennas with fewer components and radiative elements with higher gains. Smallscale (i.e. on the micro- and nano-scale) and ultra high frequency (in the Terahertz or THz range)fractal antennas composed of Graphene have the potential to enhance wireless communicationsat a data rate that is unprecedented, i.e.∼1012bits per second. A Fractal Graphene antennais a high-frequency tuneable antenna for radio communications in the …

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Line-Of-Sight Rate Construction For A Roll-Pitch Gimbal Via A Virtualpitch-Yaw Gimbal, Oğuzhan Çi̇fdalöz Jan 2021

Line-Of-Sight Rate Construction For A Roll-Pitch Gimbal Via A Virtualpitch-Yaw Gimbal, Oğuzhan Çi̇fdalöz

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a method to construct the line of sight rate of a target with a roll-pitch gimbal and tracker is described. Construction of line-of-sight rate is performed via utilizing a virtual pitch-yaw gimbal. Kinematics of both the roll-pitch and pitch-yaw gimbals are described. A dynamical model for the roll-pitch gimbal is developed, and a nested control structure is designed to control the angular rates and line of sight angles. A kinematic model of the tracker is developed and a tracker controller is designed to keep the target in the field of view. Conversion equations between roll-pitch and pitch-yaw …

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An Integrated Optimal Method For Cloud Service Ranking, Mohammad Hossein Nejat, Homayun Motameni, Hamed Vahdat-Nejad Jan 2021

An Integrated Optimal Method For Cloud Service Ranking, Mohammad Hossein Nejat, Homayun Motameni, Hamed Vahdat-Nejad

Turkish Journal of Electrical Engineering and Computer Sciences

Many cloud providers present various services with different attributes. It is a complex, lengthy process to select a cloud service that meets user requirements from an assortment of services. At the same time, user requirements are sometimes defined with imprecision (sets or intervals), whereas it is also important to consider the quality of user feedback (QoU) and quality of service (QoS) attributes for ranking. Besides, each MADM method has a di erent procedure, which causes functional contradictions. These contradictions have led to confusion in choosing the best MADM method. It is necessary to provide a method that harmonizes the results. …

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Key Success Factors Identification For Logistics Outsourcing In Myanmar, Pyae Sone Htoon Jan 2021

Key Success Factors Identification For Logistics Outsourcing In Myanmar, Pyae Sone Htoon

Chulalongkorn University Theses and Dissertations (Chula ETD)

The purpose of this paper is to identify the key success factors that have a profound effect on the service quality of outsourced logistics functions in the import/export sector of trade business in Myanmar and rank them accordingly to their importance when outsourcing logistics functions. The paper states the critical elements required for logistics service providers to compete for high customer satisfaction in Yangon, Myanmar. Fuzzy TOPSIS methodology with triangular fuzzy numbers is used to identify the key success factors and rank them in order of their relative closeness to the ideal solution. The findings suggest that soft factors such …

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Supporting Shrinkage: Planning And Decision Making For Legacy Cities, Michael P. Johnson Jr., Justin Hollander, Eliza Whiteman Kinsey, George Chichirau, Charla Burnett Jan 2021

Supporting Shrinkage: Planning And Decision Making For Legacy Cities, Michael P. Johnson Jr., Justin Hollander, Eliza Whiteman Kinsey, George Chichirau, Charla Burnett

Public Policy and Public Affairs Faculty Publication Series

Supporting Shrinkage describes a new approach to citizen-engaged, community-focused planning methods and technologies for cities and regions facing decline, disinvestment, shrinkage, and social and physical distress. The volume evaluates the benefits and costs of a wide range of analytic approaches for designing policy and planning interventions for shrinking cities and distressed communities. These include collaborative planning, social media, civic technology, game design, analytics, decision modeling and decision support, and spatial analysis. The authors present case studies of three US cities addressing shrinkage and decline, with a focus on issues of social justice, democratization of knowledge, and local empowerment. Proposed as …

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The Digitization Of Court Processes In African Regional And Subregional Judicial Institutions, Frederic Drabo Jan 2021

The Digitization Of Court Processes In African Regional And Subregional Judicial Institutions, Frederic Drabo

Walden Dissertations and Doctoral Studies

Despite information technology (IT) officers’ multiple efforts to develop reliable and efficient electronic justice (e-justice) systems, digitizing court processes still presents several quality challenges associated with IT infrastructure and literacy issues. Grounded in the principles of total quality management, the purpose of this qualitative multiple case study was to identify strategies and best practices IT officers in African regional economic communities (REC) use for digitizing regional and subregional court processes to improve African e-justice systems. The participants included four IT officers working as assistant computer system analysts (ACSA), computer system analysts (CSA), and heads of IT (HIT) in regional and …

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Sensing Population Distribution From Satellite Imagery Via Deep Learning:Model Selection, Neighboring Effects, And Systematic Biases, Xiao Huang, Di Zhu, Fan Zhang, Tao Liu, Xiao Li, Lei Zou Jan 2021

Sensing Population Distribution From Satellite Imagery Via Deep Learning:Model Selection, Neighboring Effects, And Systematic Biases, Xiao Huang, Di Zhu, Fan Zhang, Tao Liu, Xiao Li, Lei Zou

Geosciences Faculty Publications and Presentations

The rapid development of remote sensing techniques provides rich, large-coverage, and high-temporal information of the ground, which can be coupled with the emerging deep learning approaches that enable latent features and hidden geographical patterns to be extracted. This article marks the first attempt to cross-compare performances of popular state-of-the-art deep learning models in estimating population distribution from remote sensing images, investigate the contribution of neighboring effect, and explore the potential systematic population estimation biases. We conduct an end-to-end training of four popular deep learning architectures, i.e., VGG, ResNet, Xception, and DenseNet, by establishing a mapping between Sentinel-2 image patches and …

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การผลิตฟิล์มดูดกลืนยูวีจากลิกโนซัลโฟเนตที่สังเคราะห์จากลิกนินในน้ำดำของการผลิตเยื่อชานอ้อยด้วยวิธีโซดา, ชลธิดา บุญตามส่ง Jan 2021

การผลิตฟิล์มดูดกลืนยูวีจากลิกโนซัลโฟเนตที่สังเคราะห์จากลิกนินในน้ำดำของการผลิตเยื่อชานอ้อยด้วยวิธีโซดา, ชลธิดา บุญตามส่ง

Chulalongkorn University Theses and Dissertations (Chula ETD)

ในขั้นตอนการผลิตเยื่อกระดาษด้วยวิธีโซดาจะเกิดของเสียขึ้นเรียกว่า น้ำดำ ซึ่งมีลิกนินเป็นองค์ประกอบหลัก ลิกนินที่ได้นั้นสามารถนำไปสังเคราะห์เป็นลิกโนซัลโฟเนตซึ่งมีสมบัติเป็นสารอิมัลซิไฟเออร์และสามารถดูดกลืนรังสียูวี งานวิจัยนี้จึงได้ศึกษาการผลิตแผ่นฟิล์มดูดกลืนยูวีจากลิกโนซัลโฟเนตที่สังเคราะห์จากลิกนินในน้ำดำที่ได้จากการผลิตเยื่อชานอ้อยด้วยวิธีโซดา โดยเริ่มจากการศึกษาผลของความเข้มข้นของโซเดียมไฮดรอกไซด์ในกระบวนการผลิตเยื่อต่อการสกัดลิกนิน โดยทดลองใช้ความเข้มข้นของโซเดียมไฮดรอกไซด์ในการต้มเยื่อที่ร้อยละ 12, 14, 16 และ 18 ของน้ำหนักเยื่อแห้ง เนื่องจากลิกนินมีความสามารถในการละลายที่ต่ำในตัวกลางที่เป็นกรด จึงได้ทำการแยกลิกนินโดยวิธีการเติมกรดซัลฟิวริกในน้ำดำ พบว่าลิกนินที่ได้จากความเข้มข้นของโซเดียมไฮดรอกไซด์แตกต่างกันจะมีโครงสร้างเหมือนกันและเมื่อเพิ่มความเข้มข้นของโซเดียมไฮดรอกไซด์ในการต้มเยื่อจะได้ปริมาณลิกนินที่เพิ่มขึ้น การใช้ความเข้มข้นของโซเดียมไฮดรอกไซด์ที่ร้อยละ 12 ให้อัตราส่วนลิกนินต่อสารเคมีสูงที่สุดจึงได้เลือกลิกนินที่ได้จากภาวะนี้ไปตกตะกอนและนำไปสังเคราะห์เป็นลิกโนซัลโฟเนตผ่านปฏิกิริยาเมทิลซัลโฟเนชันโดยใช้ฟอร์มาลดีไฮด์และโซเดียมซัลไฟต์ พบว่าลิกโนซัลโฟเนตที่สังเคราะห์ได้ภายในงานวิจัยมีโครงสร้างคล้ายกับลิกโนซัลโฟเนตเชิงการค้า จากนั้นได้นำลิกโนซัลโฟเนตที่สังเคราะห์ได้ผสมกับพอลิเมอร์ที่สามารถย่อยสลายได้ เพื่อศึกษาสมบัติต่างๆ ของฟิล์ม ลักษณะของฟิล์มที่ได้มีความเป็นเนื้อเดียวกันแสดงถึงความเข้ากันได้ระหว่างลิกโนซัลโฟเนตและพอลิเมอร์ ฟิล์มที่ผสมลิกโนซัลโฟเนตสามารถดูดกลืนรังสีในช่วงยูวีได้ทั้งหมด เนื่องจากมีหมู่โครโมฟอร์ซึ่งมีความสามารถในการดูดกลืนยูวีอยู่ในโครงสร้าง ฟิล์มที่ผสมลิกโนซัลโฟเนตนั้นผิวหน้าของฟิล์มจะมีความชอบน้ำมากขึ้น การเติมลิกโนซัลโฟเนตที่สังเคราะห์ในงานวิจัยสามารถปรับปรุงสมบัติเชิงกลของฟิล์มได้โดยจะไปเพิ่มความต้านทานแรงดึงของฟิล์มและค่ายังมอดูลัส จากการศึกษาสภาวะที่เหมาะสมโดยวิธีพื้นที่ผิวตอบสนองพบว่าความเข้มข้นที่เหมาะสมต่อการผลิตฟิล์มที่ต้านทานยูวีได้ร้อยละ 97 พบว่าต้องผสมลิกโนซัลโฟเนตที่ความเข้มข้นร้อยละ 0.29 โดยน้ำหนักต่อปริมาตร ปริมาณพอลิไวนิลแอลกอฮอล์ที่ความเข้มข้นร้อยละ 0.89 โดยน้ำหนักต่อปริมาตร และกลีเซอรอลร้อยละ 0.89 โดยปริมาตร

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Application Of A Novel Ventilation Simplification Algorithm, Caitlin V. Strong Jan 2021

Application Of A Novel Ventilation Simplification Algorithm, Caitlin V. Strong

Theses and Dissertations--Mining Engineering

Ventilation network analysis is an integral part of maintaining a safe mine environment. Despite its important role, liberties are often taken with the representation of networks in ventilation network analysis software. In order to provide an alternative to heuristic methods used by ventilation engineers, a simplification algorithm has been developed. This algorithm is designed to work as a compliment to ventilation software. Comparisons of original ventilation networks and simplified networks show little to no change in fan operating point. The program utilizing this algorithm provides an alternative to reducing networks with a parallel factor. It can also be used in …

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