Engineering Commons^™

The Effect Of Blast Loading On Concrete Blast Walls With Different Materials And Geometries, Mohamed Hazem Awad, Aya Elhozayen

Civil Engineering

Blast loading tests have been developed in air by using ANSYS-AUTODYN program for simulation. The fourteen simulated models mainly conducted in four phases as first phase is discussing four models grouped in Group 1 consists of four concrete blast walls with double layer that subjected to four different masses of TNT (10, 50, 100, 500) kg. The main purpose for this group results to choose the proper TNT mass to use in the next phases of the research to make the comparison between models, involving pressure and damage, more obvious. The most appropriate mass is 100kg TNT to differentiate the …

Incorporation Of Perlite And Recycled Aggregates For Internal Concrete Curing, Yosra El Maghraby, Mohamed Nagib Abou-Zeid Prof., Mohamed Abdel-Raouf Dr.

Civil Engineering

No abstract provided.

Potential Advantages Of Basalt Frp Bars Compared To Carbon Frp Bars & Conventional Steel, Yosra El Maghraby, Mohamed Nagib Abou-Zeid Prof., Ezzeldeen Yazeed El Sayed Ahmed Prof

Civil Engineering

No abstract provided.

Quantification Of Nitric Oxide Concentration Using Single-Walled Carbon Nanotube Sensors, Jakob Meier, Joseph Stapleton, Eric M. Hofferber, Abigail Haworth, Stephen D. Kachman, Nicole M. Iverson

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Nitric oxide (NO), a free radical present in biological systems, can have many detrimental effects on the body, from inflammation to cancer. Due to NO’s short half-life, detection and quan- tification is difficult. The inability to quantify NO has hindered researchers’ understanding of its impact in healthy and diseased conditions. Single-walled carbon nanotubes (SWNTs), when wrapped in a specific single-stranded DNA chain, becomes selective to NO, creating a fluorescence sensor. Unfortunately, the correlation between NO concentration and the SWNT’s fluorescence intensity has been difficult to determine due to an inability to immobilize the sensor without altering its properties. Through the …

Reducing Attack Vulnerabilities Through Decentralized Event-Triggered Control, Paul Griffioen, Raffaele Romagnoli, Bruce H. Krogh, Bruno Sinopoli

Faculty Work Comprehensive List

Decentralized control systems are widely used in a number of situations and applications. In order for these systems to function properly and achieve their desired goals, information must be propagated between agents, which requires connecting to a network. To reduce vulnerabilities to attacks that may be carried out through the network, we design an event-triggered mechanism for network connection and communication that minimizes the amount of time agents must be connected to the network, in turn decreasing communication costs. This mechanism is a function of only local information and ensures stability for the overall system in attack-free scenarios. Our approach …

Fifnet: A Convolutional Neural Network For Motion-Based Multiframe Super-Resolution Using Fusion Of Interpolated Frames, Hamed Elwarfalli, Russell C. Hardie

Electrical and Computer Engineering Faculty Publications

We present a novel motion-based multiframe image super-resolution (SR) algorithm using a convolutional neural network (CNN) that fuses multiple interpolated input frames to produce an SR output. We refer to the proposed CNN and associated preprocessing as the Fusion of Interpolated Frames Network (FIFNET). We believe this is the first such CNN approach in the literature to perform motion-based multiframe SR by fusing multiple input frames in a single network. We study the FIFNET using translational interframe motion with both fixed and random frame shifts. The input to the network is a sequence of interpolated and aligned frames. One key …

Using Smart-Wifi Thermostat Data To Improve Prediction Of Residential Energy Consumption And Estimation Of Savings, Abdulrahman Alanezi, Kevin P. Hallinan, Rodwan Elhashmi

Mechanical and Aerospace Engineering Faculty Publications

Energy savings based upon use of smart WiFi thermostats ranging from 10 to 15% have been documented, as new features such as geofencing have been added. Here, a new benefit of smart WiFi thermostats is identified and investigated; namely, as a tool to improve the estimation accuracy of residential energy consumption and, as a result, estimation of energy savings from energy system upgrades, when only monthly energy consumption is metered. This is made possible from the higher sampling frequency of smart WiFi thermostats. In this study, collected smart WiFi data are combined with outdoor temperature data and known residential geometrical …

Ieee Access Special Section Editorial: Trends And Advances In Bio-Inspired Image-Based Deep Learning Methodologies And Applications, Peter Peer, Carlos M. Travieso-Gonzalez, Vijayan K. Asari, Malay Kishore Dutta

Electrical and Computer Engineering Faculty Publications

Many of the technological advances we enjoy today have been inspired by biological systems due to their ease of operation and outstanding efficiency. Designing technological solutions based on biological inspiration has become a cornerstone of research in a variety of areas ranging from control theory and optimization to computer vision, machine learning, and artificial intelligence. Especially in the latter few areas, biologically relevant solutions are becoming increasingly important as we look for new ways to make artificial systems more efficient, intelligent, and overall effective.

Flight Data Management And Pilot Protection In An Ads-B World, James Norman

Aviation Faculty Publications

Airlines and unions need to reconsider and reimagine what flight operational quality assurance (FOQA) data is, its use and protection. Open-source flight data, such as ADS-B, needs to be protected as strongly as traditional FOQA data for US operators. Airlines and unions should adopt contractual language that expands FOQA protections to all recording and transmitting devices, future proofing against emerging and novel technologies.

Assessing The Relationships Between Organizational Management Factors (4ps) And A Resilient Safety Culture In A Collegiate Aviation Program With A Safety Management Systems (Sms), Daniel Kwasi Adjekum

Aviation Faculty Publications

Resilient safety culture is a key factor in sustaining safety management systems (SMS) in a U.S. collegiate aviation program. The relationships between four organizational management factors (Principles, Policy, Procedures, Practices) and a resilient safety culture model based on Reason’s concept was assessed using an online survey instrument. Structural Equation Model (SEM) technique were used to assess measurement models of factors underlying a resilient safety culture. All four management factors had significant predictive relationship with resilient safety culture. Practices had the weakest predictive relationship with resilient safety culture and Policy had the highest. Procedures strongly mediated path between Policies and Practices …

Index-Based Approach With Remote Sensing For The Assessment Of Extreme Weather Impact On Watershed Vegetation Dynamics, Kushan Bellanthudawage

Electronic Theses and Dissertations, 2020-2023

Spatial technologies such as satellite remote sensing can be used to identify vegetation dynamics over space and time, which play a critical role in earth observations. Biophysical and biochemical features associated with vegetation cover can then be used to elucidate climate change impact such as floods and droughts on ecosystem that may in turn affect watershed-scale water resources management. Unlike single flood or drought event, intermittent extreme weather events may exert more physiological and biological pressures on the canopy vegetation. This study aims to investigate the climate change impacts on canopy vegetation, which occurred from March 2017 to October 2017 …

Performance Enhancement Of Rf/Microwave Devices Using Filter Synthesis Techniques, Ricardo Lovato

Electronic Theses and Dissertations, 2020-2023

This dissertation shows that filter synthesis techniques can be used to design and enhance the performance of several discrete components of the RF front-end. Throughout this work, a block diagram of a typical receiver is used to illustrate each component separately. Four main areas are covered: (1) filter/antenna integration, (2) frequency-tunable filter/antenna integration with control of the bandwidth characteristics, (3) antenna arrays designed based on integrated cavity resonators, and (4) novel low-loss phase shifters using band-pass and band-stop filters. The filter/antenna designed using two cavity resonators with a slot antenna in the second cavity. The slot antenna excites two modes …

Identifying The Links Between Mental Frameworks, Context Features, And Driver Attention In Complete Streets Environments, Patricia Tice

Electronic Theses and Dissertations, 2020-2023

Complete street systems integrate a wide range of users in the same space, with unequal risks and responsibilities. This makes driver attention a critical factor in assuring the safety of vulnerable users. The Conditioned Anticipation of People psychological model of driver attention proposes that drivers reflexively reengage their metacognitive processes when they anticipate visually interacting with the human face or form due to the neurological priority that the brain places on human recognition. To test this model, an eye-tracking tabulation was generated from the SHRP2 Naturalistic Driving Study that measured midsegment percent of time on-task and multitasking behavior for 200 …

Studies On Powder Compaction And Wire Extrusion Of Pure Metals And Metal/Cnt Nano Composites, Qiang Zhou

Electronic Theses and Dissertations, 2020-2023

The goal of this dissertation is to fabricate wires made of Cu/CNT and Al/CNT composites with good mechanical strength and super thermal/electrical conductivities using powder compaction and wire extrusion manufacturing processes. Powder compaction was studied using both test and simulation. Cold compaction, hot compaction and vibration assisted (cold) compaction tests were conducted to achieve different density ratios. Hot compaction tests improved about 6% compared with cold compaction under the same compression pressure. Although the relative density ratio does not obviously improve at vibration assisted (cold) compaction, the strength of the specimens made under vibration loading is much better than those …

Distributed Service Restoration In Active Distribution Networks, Nejad Reza Roofegari

Electronic Theses and Dissertations, 2020-2023

Despite tremendous efforts on increasing power system reliability, outages and blackouts are inevitable. These losses can be greatly reduced by fast and reliable restoration mechanisms. Largescale distribution networks and increasing penetration of distributed energy resources (DERs) make restoration one of the most challenging problems in power systems. The prevailing centralized restoration scheme is costly, limited by information privacy of entities, unreliable due to dependence on central units, and might suffer from single-point failures. In this dissertation, a fully distributed restoration framework based on the alternating direction method of multipliers (ADMM) is proposed to address these challenges. Accordingly, the restoration problem …

An Evaporation Based Micro-Synthetic Jet In Microchannel And Its Applications, Ehsan Sourtiji

Electronic Theses and Dissertations, 2020-2023

An approach to create synthetic jets at micro-scales using periodic bubble growth and collapse was presented and studied over a range of operating frequencies (0.1 to 2.5 Hz) and heating powers (3 to 4.5 Watt). The microfluidic device uses an interfacial layer between vapor and liquid phases which substitutes the requirement for a physical flexible membrane and any other moving parts. The bubble explosion and implosion in the chamber was triggered by periodically powering a micro-heater, which in turn generated the synthetic jet. High-speed camera photography and a microscope were used to capture sequential images of bubble nucleation, growth and …

การศึกษากลไกและเกณฑ์การจ่ายค่าตอบแทนและความเสี่ยงของผู้มีส่วนได้เสียหลักในสัญญา Ppp O&M ของโครงการทางหลวงระหว่างเมืองในประเทศไทย, นันทพัฒน์ ปิ่นตบแต่ง

Chulalongkorn University Theses and Dissertations (Chula ETD)

ปัจจุบันรัฐได้เปิดโอกาสให้เอกชนเข้ามาร่วมลงทุนในโครงการของรัฐในรูปแบบของการจ้างดำเนินงานและบำรุงรักษาโครงการ (PPP O&M) สัญญารูปแบบดังกล่าว รายได้จากการเก็บค่าผ่านทางจะเป็นของรัฐทั้งหมด แล้วจ่ายผลตอบแทนให้กับเอกชนในลักษณะอัตราเหมาจ่าย โดยรัฐต้องแบกรับความเสี่ยงด้านการตลาด (Market risk) เช่น ความเสี่ยงด้านปริมาณจราจร เป็นต้น ส่วนเอกชนแบกรับความเสี่ยงด้านการลงทุนงานระบบ และค่ายใช้จ่ายในการดำเนินงานและบำรุงรักษา สัญญา PPP O&M ได้นำกลไกการจ่ายค่าตอบแทน (Payment mechanisms) ที่เรียกว่า “Availability Payment หรือ AP” โดยอาจจะมีการปรับลดค่าตอบแทน (Payment Adjustment) ถ้าเอกชนผู้ให้บริการไม่สามารถรักษาสภาพความพร้อมใช้และคุณภาพของการให้บริการได้ตามสัญญา งานวิจัยนี้มีวัตถุประสงค์เพื่อศึกษากลไกการจ่ายค่าตอบแทนตามความพร้อมใช้ และเกณฑ์การคำนวณการปรับค่าตอบแทนของสัญญา PPP O&M และเพื่อสร้างกรอบการคำนวณ (Computational framework) สำหรับวิเคราะห์ผลตอบแทนทางการเงิน ปัจจัยเสี่ยงและระดับความเสี่ยง (Risk variables and risk profile) ของผู้มีส่วนได้เสียหลัก ได้แก่ (1) รัฐเจ้าของโครงการ (2) เอกชนผู้ให้บริการ และ (3) สถาบันการเงินผู้ให้เงินกู้ยืม ทั้งนี้เพื่อใช้เป็นเครื่องมือประกอบการตัดสินใจของผู้มีส่วนได้เสียหลักในการพัฒนากลไกการจ่ายค่าตอบแทน โดยงานวิจัยนี้ใช้โครงการทางหลวงพิเศษระหว่างเมืองหมายเลข 6 บางปะอิน - นครราชสีมา เป็นโครงการกรณีศึกษา ผลการศึกษาพบว่ากรอบการคำนวณที่ได้พัฒนาสามารถนำมาใช้ในการประเมินผลตอบแทนทางการเงินและระดับของความเสี่ยงของแต่ละฝ่าย โดยแสดงผลการประเมินความเสี่ยงในรูปแบบ Risk profile เพื่อนำไปสู่การบริหารจัดการความเสี่ยงให้เป็นที่ยอมรับของทุกฝ่าย

การพยากรณ์ปริมาณและความเข้มข้นสารฟลอกคูแลต์ในกระบวนการพักใสสำหรับอุตสาหกรรมการผลิตน้ำตาลจากอ้อย, สิงหดิศร์ จันทรักษ์

Chulalongkorn University Theses and Dissertations (Chula ETD)

กระบวนการพักใสเป็นกระบวนการที่สำคัญในกระบวนการผลิตน้ำตาล ซึ่งกระบวนการมีการทำงานเพื่อแยกระหว่างตะกอนกับน้ำอ้อยออกจากกันโดยใช้สารฟลอกคูแลนต์ โดยในการใส่ปริมาณและความเข้มข้นสารฟลอกคูแลนต์ลงไปในน้ำอ้อยทำให้ส่งผลกระทบโดยตรงต่อความเร็วการตกตะกอนและค่าความขุ่นของน้ำอ้อย วิทยานิพนธ์เล่มนี้เสนอวิธีการพยากรณ์ปริมาณและความเข้มข้นสารฟลอกคูแลต์ในกระบวนการพักใสสำหรับอุตสาหกรรมการผลิตน้ำตาลจากอ้อย โดยใช้โครงข่ายประสาทเทียมแบบวนซ้ำชนิดพิเศษ Long Short-Term Memory โดยข้อมูลที่นำมาใช้เป็นข้อมูลขาเข้าสำหรับการสร้างโมเดลได้แก่ ปริมาณอ้อยสด, ปริมาณอ้อยเผา, ความขุ่นของน้ำอ้อย และปริมาณน้ำฝน และข้อมูลขาออกได้แก่ ปริมาณและความเข้มข้นของสารฟลอกคูแลนต์ ทั้งนี้ข้อมูลที่ได้นำมาจากโรงงานผลิตน้ำตาลแห่งหนึ่งในประเทศไทย ผลการทดลองแสดงให้เห็นถึงประสิทธิภาพของโมเดลที่ได้นำเสนอ LSTM โดยการเปรียบเทียบกับโมเดลอื่นๆ ได้แก่ Autoregressive Integrated Moving Average (ARIMA), Recurrent Neural Network (RNN) และ Gated Recurrent Unit (GRU) โดยใช้ตัวแปร RMSE และ MAPE เป็นตัววัดประสิทธิภาพของโมเดล พบว่าโมเดลที่นำเสนอมีประสิทธิภาพที่สุดในการพยากรณ์ปริมาณและความเข้มข้นของสารฟลอกคูแลนต์

การจำแนกปัญหาของเทคโนโลยีฐานข้อมูลในชุมชนถามตอบออนไลน์, ณัฐนัย สุวรรณชูชิต

Chulalongkorn University Theses and Dissertations (Chula ETD)

วิทยานิพนธ์นี้นำเสนอแนวทางการสร้างเครื่องมือการทำงานอัตโนมัติเพื่อจำแนกคำถามบนเว็บไซต์สแต็กโอเวอร์โฟลว์ โดยเฉพาะที่เกี่ยวกับชนิดของผลิตภัณฑ์ฐานข้อมูล ซึ่งถือเป็นข้อมูลที่มีค่าสำหรับเจ้าของผลิตภัณฑ์ฐานข้อมูลในการนำไปปรับปรุงผลิตภัณฑ์ หมวดหมู่ของคำถามกำหนดไว้เป็นสองระดับได้แก่ ระดับปัญหา และ ปัญหาย่อย โดยที่ระดับปัญหาประกอบด้วย การพัฒนา การติดตั้ง และ การปรับปรุงประสิทธิภาพ ในขณะที่ ปัญหาย่อย ประกอบด้วย การออกแบบ ข้อจำกัด และการอภิปรายปัญหา ด้วยการรวมทั้งสองระดับเข้าด้วยกัน คำถามจะถูกจำแนกออกเป็นเก้าหมวดของปัญหา-ปัญหาย่อย การประมวลผลภาษาธรรมชาติและการจำแนกข้อความถูกนำมาใช้ โดยใช้อัลกอริทึมการเรียนรู้ของเครื่องที่หลากหลาย โมเดลการจำแนกประเภทที่มีประสิทธิภาพดีที่สุดจะถูกนำมาใช้ในเว็บแอปพลิเคชัน เพื่อจำแนกแต่ละคำถามโดยใช้แท็กปัญหา-ปัญหาย่อย นอกจากนี้คำถามที่ถูกจำแนกออกตามหมวดแล้ว สามารถนำมาวิเคราะห์เพิ่มเติมโดยใช้อัลกอริทึมการสร้างแบบจำลองหัวข้อ เพื่อให้ทราบว่าคำถามในแต่ละหมวดนั้นกล่าวถึงหัวข้อใดบ้าง ซึ่งจะเป็นข้อมูลเพิ่มเติมให้กับเจ้าของผลิตภัณฑ์ฐานข้อมูลในการทำความเข้าใจถึงปัญหาของผลิตภัณฑ์เพื่อจะได้ทำการปรับปรุงต่อไป

Cyclic Sequential Adsorption Desorption/Thermal-Catalytic Oxidation Of Volatile Organic Compounds: Material Development, Process Advancement/Improvement, And Numerical Modeling, Simulation And Optimization, Busuyi Ojo Adebayo

Doctoral Dissertations

"Volatile organic compounds (VOCs) are a group of useful organic chemicals but when emitted have contributed to air pollution. They affect human health, cause environmental degradation and contaminate our waters and soils, so they need to be controlled. When they exist in dilute concentrations, abatement becomes challenging, thus requiring advanced abatement methods, e.g., sequential adsorption desorption/thermal-catalytic oxidation process. The overall goal of this research was to abate dilute streams of VOCs via the process. The specific objectives were to 1) develop novel adsorbent/catalyst dual-function materials (DFMs) for the process, 2) improve the operability of a one-bed-one-column reactor configuration for the …

A Simple Background Elimination Method For Miniaturized Fiber-Optic Raman Probe, Bohong Zhang

Masters Theses

"Raman scattering is called a photonic - molecular interaction based on the kinetic model of the analytic. Due to the uniqueness of the Raman scattering technique, it can provide a unique fingerprint signal for molecular recognition. However, a serious challenge often encountered in Raman measurement comes from the requirements of fast, real-time remote sensing, background fluorescence suppression, and micro-environmental detection.

A new Miniaturized Fiber-Optic Raman Probe (MFORP) for Raman spectroscopy, used especially for eliminating background fluorescence and enhancing sampling, is presented. Its main purpose is to provide an overview of excellent research on the detection of very small substances and …

Design And Evaluation Of The 3d Printed Electromagnetic Absorber Built With Conductive Carbon-Filled Filament, Rui Mi

Masters Theses

"This research presents an application of the resistive frequency selective surface (FSS) fabricated with a 3D printed conductive material as an electromagnetic absorber for the EMI-reducing door. This solution allows to reduce radiated emissions of a router system. The resistive frequency selective surface has a three-layer structure. The top layer is a 3D printed FSS pattern, the middle layer is an air gap, and the bottom layer is a metal plane.

The first paper presents the methodology for manufacturing a frequency selective surface using the 3D printing technology, including the material characterization, design, fabrication, and evaluation.

The unpublished content presents …

Early Wildfire Detection By Air Quality Sensors On Unmanned Aerial Vehicles: Optimization And Feasibility, Doaa Rjoub

Masters Theses

“Millions of acres of forests are destroyed by wildfires every year, causing ecological, environmental, and economical losses. The recent wildfires in Australia and the Western U.S. smothered multiple states with more than fifty million acres charred by the blazes. The warmer and drier climate makes scientists expect increases in the severity and frequency of wildfires and the associated risks in the future. These inescapable crises highlight the urgent need for early detection and prevention of wildfires. This work proposed an energy management framework that integrated unmanned aerial vehicle (UAV) with air quality sensors for early wildfire detection and forest monitoring. …

Fabrication Of Silicon Nitride Parts By Ceramic On-Demand Extrusion Process, Sachin Choudhary

Masters Theses

“Ceramic On-Demand Extrusion (CODE) is a patented solid freeform fabrication method for manufacturing high-density monolithic ceramic parts. In the past 5-6 years, the technology has been successfully implemented to fabricate alumina and zirconia parts. The mechanical characterizations also show CODE’s high potential in achieving desired structural properties. The present study covers the fabrication of silicon nitride parts by CODE process, which entailed the design of paste formulation for achieving rheology suitable for dimensional control in fabricated parts and determining firing temperature and the content of sintering additives for silicon nitride green bodies fabricated by CODE. The density, hardness, and fracture …

Effect Of Spike Anchors On The Bond Behavior Of Steel Reinforced Polymer Composite Externally Bonded To A Concrete Substrate, Keenan Lorence Mcburney

Masters Theses

Steel reinforced polymer (SRP) composites are a strengthening material that consist of continuous high-strength steel cords embedded in a polymeric matrix. SRP has demonstrated a high potential for providing additional flexural and shear strength in existing concrete structures when bonded to the concrete surface. However, premature debonding from the concrete substrate at low load levels is a major shortcoming of SRP composites. It has been demonstrated in previous studies that anchors can limit the effect of debonding in fiber reinforced polymer (FRP) composites by increasing the load capacity and ductility of the composite-concrete interface.

This study aims to investigate the …

Physics-Based Modeling Of Lithium-Ion Batteries For Control And Estimation Applications, Brody J. C. Riemann

Masters Theses

“Lithium-ion batteries are extensively used in many application areas like consumer electronics, electric vehicles, and microgrids. As the world moves towards further electrification of vehicles and more widespread use of renewable energy sources, the need for large-scale battery storage systems will grow. To effectively replace conventional methods, batteries will need to be charged quickly while accounting for degradation to maximize lifetime. Further, larger batteries require more detailed safety monitoring, which is implemented using a battery management system (BMS). A BMS is responsible for state of charge (SOC) estimation, state of health (SOH) estimation, cell balancing, regulating voltage and current according …

Hygrothermal Ageing Behavior And Mechanism Of Carbon Nanofibers Modified Flax Fiber-Reinforced Epoxy Laminates, Yanlei Wang, Wanxin Zhu, Baolin Wan, Ziping Meng, Baoguo Han

Civil and Environmental Engineering Faculty Research and Publications

This study investigated the effects of carbon nanofibers (CNFs) content on hygrothermal ageing behaviors and mechanisms of flax fiber-reinforced epoxy (FFRE) laminates. CNFs/FFRE laminates containing 0.25–2.0 wt% CNFs were fabricated and immersed in distilled water for 180 days. Water absorption and tensile as well as thermodynamic properties were investigated. The research results showed that CNFs played a significant role in the improvement of hygrothermal properties of FFRE laminates. The water uptake of CNFs/FFRE laminates was significantly decreased because CNFs improved water barrier properties of the laminates. The improvements of tensile and thermodynamic properties of CNFs/FFRE laminates were attributed to the …

Event-Driven Servers Using Asynchronous, Non-Blocking Network I/O: Performance Evaluation Of Kqueue And Epoll, Lorcan Leonard

Dissertations

This research project evaluates the performance of kqueue and epoll in the context of event-driven servers. The evaluation is done through benchmarking and tracing which are used to measure throughput and execution time respectively. The experiment is repeated for both a virtualised and native server environment. The results from the experiment are statistically analysed and compared. These results show significant differences between kqueue and epoll, and a profound impact of virtualisation as a variable.

A Two-Level Information Modelling Translation Methodology And Framework To Achieve Semantic Interoperability In Constrained Geoobservational Sensor Systems, Paul Stacey

Doctoral

As geographical observational data capture, storage and sharing technologies such as in situ remote monitoring systems and spatial data infrastructures evolve, the vision of a Digital Earth, first articulated by Al Gore in 1998 is getting ever closer. However, there are still many challenges and open research questions. For example, data quality, provenance and heterogeneity remain an issue due to the complexity of geo-spatial data and information representation.

Observational data are often inadequately semantically enriched by geo-observational information systems or spatial data infrastructures and so they often do not fully capture the true meaning of the associated datasets. Furthermore, data …

A High Efficiency And Low Cost Anpc Inverter Using Hybrid Si/Sic Switches, Dereje Woldegiorgis, Yuheng Wu, Yuqi Wei, H. Alan Mantooth

Electrical Engineering Faculty Publications and Presentations

This paper presents a performance investigation and design optimization of a high efficiency three-level Active Neutral Point Clamped (ANPC) inverter topology using hybrid Si/SiC switches. It uses a modulation strategy that produces a cluster of low frequency switches commutating at fundamental line frequency (realized with Si IGBTs) and high frequency switches commutating at carrier frequency (realized with hybrid Si/SiC switches) to facilitate a tradeoff between the inverter efficiency and cost. A generalized Si/SiC current rating ratio optimization algorithm is presented for the hybrid Si/SiC switches based on the power loss profile of ANPC inverter. This algorithm determines the optimal current …