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Full-Text Articles in Engineering

Silicon Based Schottky Diodes And Mos Capacitors For Sensing Singly And Multiply Charged Ions With Low Kinetic Energy, Daniel Blaine Cutshall Iii May 2019

Silicon Based Schottky Diodes And Mos Capacitors For Sensing Singly And Multiply Charged Ions With Low Kinetic Energy, Daniel Blaine Cutshall Iii

All Dissertations

This study provides the foundation for the development of radiation detection technology of slow ions by investigating the fundamental interactions of slow ion beams with electronic devices. Silicon samples with a 50 nm oxide layer were irradiated with 1 keV ArQ+ beams (Q = 4, 8, and 11) at normal incidence in order to investigate the relatively unexplored effects of slow highly charged ions (HCIs) on electronic devices. After irradiation, an array of metal contacts was deposited onto the oxidized silicon samples to create metal oxide semiconductor (MOS) capacitors, which were then characterized using high frequency capacitance-voltage (C-V) measurements. The ...


Polymer Injection Forming: A New Age Technology For Manufacturing Polymer-Metal Hybrids, Saeed Farahani Dec 2018

Polymer Injection Forming: A New Age Technology For Manufacturing Polymer-Metal Hybrids, Saeed Farahani

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Due to global competition, manufacturing firms in high-wage countries must target innovation in production processes and technologies that allow the mass manufacturing of customized products through highly efficient processes. Motivated by the concept of the integrative production systems, hybrid process of polymer injection molding and sheet metal forming, known as polymer injection forming (PIF), has been introduced to manufacture sheet metal-polymer components using a single tooling, machinery, and operating system. During this process, the sheet metal blank inside the injection mold is deformed by means of tool movement and/or by pressure of the polymer melt. As the melt cools ...


Efficacy Of Smart Pv Inverter As A Strategic Mitigator Of Network Harmonic Resonance And A Suppressor Of Temporary Overvoltage Phenomenon In Distribution Systems, Shriram Srinivasarangan Rangarajan Aug 2018

Efficacy Of Smart Pv Inverter As A Strategic Mitigator Of Network Harmonic Resonance And A Suppressor Of Temporary Overvoltage Phenomenon In Distribution Systems, Shriram Srinivasarangan Rangarajan

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The research work explores the design of Smart PV inverters in terms of modelling and investigates the efficacy of a Smart PV inverter as a strategic mitigator of network harmonic resonance phenomenon and a suppressor of Temporary Overvoltage (TOV) in distribution systems. The new application and the control strategy of Smart PV inverters can also be extended to SmartPark-Plug in Electric Vehicles as the grid becomes smarter.

As the grid is becoming smarter, more challenges are encountered with the integration of PV plants in distribution systems. Smart PV inverters nowadays are equipped with specialized controllers for exchanging reactive power with ...


Micro-Cantilever Based Fiber Optic Hydrophone, Jie Liu Dec 2017

Micro-Cantilever Based Fiber Optic Hydrophone, Jie Liu

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Endoscopic photoacoustic imaging probe is becoming increasingly important for many clinical photoacoustic imaging applications in which the target tissue can only be accessed by introducing an endoscopic probe percutaneously or through a natural orifice. Miniature fiber optic hydrophone (FOH) has become an attractive choice for endoscopic photoacoustic imaging application. Fiber optic hydrophone has many proven advantages, including small size, light weight, immunity to electromagnetic interference, low cost for single-use application and capability of integration of excitation light source and acoustic wave receiver.

This dissertation demonstrates an open cavity, micro-cantilever based fiber optic Fabry-Perot interferometer (FPI) hydrophone. A fused silica micro-cantilever ...


Synthesis And Characterization Of Glycidyl Methacrylate-Based Graft Copolymer Functional Interfaces, Nikolay Brordinov Dec 2017

Synthesis And Characterization Of Glycidyl Methacrylate-Based Graft Copolymer Functional Interfaces, Nikolay Brordinov

All Dissertations

Modification of materials properties such as surface energy, wettability, ability to absorb, contain or release specific type of chemicals enables practical application of these materials in various scientific and engineering set-ups. However, designing protocol that could be easily adapted for different situations and simultaneously unlock multiple variations of the resulting properties is a non-trivial task. This dissertation is devoted to application of glycidyl methacrylate-based graft copolymers for the purposes of surface modification, establishing fundamental trends and dependencies of this process and exploring the possible range of applications. These materials have extremely valuable property to undergo controllable post-synthetic modifications including surface ...


Role Of Surface Factors On Heterogeneous Ice Nucleation, Brittany Glatz Oct 2017

Role Of Surface Factors On Heterogeneous Ice Nucleation, Brittany Glatz

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Heterogeneous ice nucleation is the primary pathway for ice formation. However, the detailed molecular mechanisms by which surfaces promote or hinder ice nucleation are not well understood. We present results from extensive molecular dynamics and forward flux sampling (FFS) simulations of ice nucleation near modified surfaces. The surfaces are modified to investigate the effects of different surface factors on the rate and mechanism of ice nucleation. We find that the surface charge distribution has significant effects on ice nucleation. We also investigate the interplay of surface lattice and hydrogen bonding properties in affecting ice nucleation. We find that lattice matching ...


Design, Synthesis And Sustainable Applications Of Animal Protein-Based Thermoset Polymers And Covalent Organic Frameworks, Xiaoyan Yu Aug 2017

Design, Synthesis And Sustainable Applications Of Animal Protein-Based Thermoset Polymers And Covalent Organic Frameworks, Xiaoyan Yu

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Extensive research has been undertaken in recent times on finding suitable, alternative, non-feed and non-fertilizer applications for proteinaceous materials in the animal rendering industry. In this regard, use of such proteins to derive plastics, especially thermoplastics and derived composites, has emerged as a potentially acceptable choice. However, the widespread use of such proteins for aforementioned applications is limited by their poor mechanical properties, high moisture absorption and their inherent odor. In this study, we have engineered, for the first time, high-strength, toughened thermoset polymers from proteinaceous materials obtained from the rendering industry so that they can be employed in high ...


Towards Structuring Smart Grid: Energy Scheduling, Parking Lot Allocation, And Charging Management, Mehdi Rahmani-Andebili Dec 2016

Towards Structuring Smart Grid: Energy Scheduling, Parking Lot Allocation, And Charging Management, Mehdi Rahmani-Andebili

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Nowadays, the conventional power systems are being restructured and changed into smart grids to improve their reliability and efficiency, which brings about better social, economic, and environmental benefits. To build a smart grid, energy scheduling, energy management, parking lot allocation, and charging management of plug-in electric vehicles (PEVs) are important subjects that must be considered. Accordingly, in this dissertation, three problems in structuring a smart grid are investigated.

The first problem investigates energy scheduling of smart homes (SHs) to minimize daily energy consumption cost. The challenges of the problem include modeling the technical and economic constraints of the sources and ...


Optimization Techniques For Modern Power Systems Planning, Operation And Control, Karthikeyan Balasubramaniam Aug 2016

Optimization Techniques For Modern Power Systems Planning, Operation And Control, Karthikeyan Balasubramaniam

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Recent developments in computing, communication and improvements in optimization techniques have piqued interest in improving the current operational practices and in addressing the challenges of future power grids. This dissertation leverages these new developments for improved quasi-static analysis of power systems for applications in power system planning, operation and control.

The premise of much of the work presented in this dissertation centers around development of better mathematical modeling for optimization problems which are then used to solve current and future challenges of power grid. To this end, the models developed in this research work contributes to the area of renewable ...


Supervisory Control Optimization For A Series Hybrid Electric Vehicle With Consideration Of Battery Thermal Management And Aging, Xueyu Zhang Aug 2016

Supervisory Control Optimization For A Series Hybrid Electric Vehicle With Consideration Of Battery Thermal Management And Aging, Xueyu Zhang

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This dissertation integrates battery thermal management and aging into the supervisory control optimization for a heavy-duty series hybrid electric vehicle (HEV). The framework for multi-objective optimization relies on novel implementation of the Dynamic Programing algorithm, and predictive models of critical phenomena. Electrochemistry based battery aging model is integrated into the framework to assesses the battery aging rate by considering instantaneous lithium ion (Li+) surface concentration rather than average concentration. This creates a large state-action space. Therefore, the computational effort required to solve a Deterministic or Stochastic Dynamic Programming becomes prohibitively intense, and a neuro-dynamic programming approach is proposed to remove ...


Towards An Efficient Cloud Computing System: Data Management, Resource Allocation And Job Scheduling, Jinwei Liu Aug 2016

Towards An Efficient Cloud Computing System: Data Management, Resource Allocation And Job Scheduling, Jinwei Liu

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Cloud computing is an emerging technology in distributed computing, and it has proved to be an effective infrastructure to provide services to users. Cloud is developing day by day and faces many challenges. One of challenges is to build cost-effective data management system that can ensure high data availability while maintaining consistency. Another challenge in cloud is efficient resource allocation which ensures high resource utilization and high SLO availability. Scheduling, referring to a set of policies to control the order of the work to be performed by a computer system, for high throughput is another challenge. In this dissertation, we ...


Effective And Economical Content Delivery And Storage Strategies For Cloud Systems, Yuhua Lin Aug 2016

Effective And Economical Content Delivery And Storage Strategies For Cloud Systems, Yuhua Lin

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Cloud computing has proved to be an effective infrastructure to host various applications and provide reliable and stable services. Content delivery and storage are two main services provided by the cloud. A high-performance cloud can reduce the cost of both cloud providers and customers, while providing high application performance to cloud clients. Thus, the performance of such cloud-based services is closely related to three issues. First, when delivering contents from the cloud to users or transferring contents between cloud datacenters, it is important to reduce the payment costs and transmission time. Second, when transferring contents between cloud datacenters, it is ...


Development Of A New Multimodal Membrane Adsorber And Its Application In Chromatographic Bioseparations, Juan Wang Aug 2016

Development Of A New Multimodal Membrane Adsorber And Its Application In Chromatographic Bioseparations, Juan Wang

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This dissertation presents work on the design and synthesis of a new membrane chromatography material, the description of its protein binding behavior using a thermodynamic adsorption isotherm model, and the application of the new membrane material in biologics downstream recovery and purification processes. As protein titers continue to increase dramatically in upstream biomanufacturing, innovations in downstream purification are not keeping pace, resulting in manufacturing capacity constraints and high production costs. Chromatography is the key unit operation used in several steps of the downstream purification platform. Traditional resin bead chromatography, while effective and reliable for isolation and purification of proteins, limits ...


Optimizing Virtual Resource Management In Cloud Datacenters, Liuhua Chen Aug 2016

Optimizing Virtual Resource Management In Cloud Datacenters, Liuhua Chen

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Datacenter clouds (e.g., Microsoft's Azure, Google's App Engine, and Amazon's EC2) are emerging as a popular infrastructure for computing and storage due to their high scalability and elasticity. More and more companies and organizations shift their services (e.g., online social networks, Dropbox file hosting) to clouds to avoid large capital expenditures. Cloud systems employ virtualization technology to provide resources in physical machines (PMs) in the form of virtual machines (VMs). Users create VMs deployed on the cloud and each VM consumes resources (e.g., CPU, memory and bandwidth) from its host PM. Cloud providers supply ...


Design Of A Wide Area Controller Using Eigenstructure Assignment In Power Systems, Parimal Saraf May 2016

Design Of A Wide Area Controller Using Eigenstructure Assignment In Power Systems, Parimal Saraf

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Small signal stability has become a major concern for power system operators around the world. This has resulted from constantly evolving changes in the power system ranging from increased number of interconnections to ever increasing demand of power. In highly stressed operating conditions, even a small disturbance such as a load change can make the system unstable resulting in small signal instability. The main reason for small signal instability in power systems is an inter-area mode/s becoming unstable. Inter-area modes involve a group of generators oscillating against each other. Traditionally, power system stabilizers installed on the synchrous machines were ...


Low Cost, Carbon-Based Micro- And Nano-Structured Electrodes For High Performance Supercapacitors, Kryssia Pamela Díaz Orellana May 2016

Low Cost, Carbon-Based Micro- And Nano-Structured Electrodes For High Performance Supercapacitors, Kryssia Pamela Díaz Orellana

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Advances in the development of sustainable, low-cost, and reliable energy storage technologies have become a high priority as the demand for high power, and high energy storage devices has risen with emerging technologies in electronics, transportation, and renewable energy systems. Supercapacitors, due to their relatively high energy density and power density, provide an attractive alternative to bridge the gap between conventional batteries and capacitors. Materials ranging from high surface area, inert carbons to Faradaic metal oxides and conducting polymers have been used to achieve a range of performance properties in supercapacitors. However, the development of new technologies faces many challenges ...


Effects Of Growth Factor Supplementation And Environmental Conditions On Human Adipose-Derived Stem Cell Differentiation Towards Urothelial Lineage, James Turner Dec 2015

Effects Of Growth Factor Supplementation And Environmental Conditions On Human Adipose-Derived Stem Cell Differentiation Towards Urothelial Lineage, James Turner

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In recent years, tissue engineering of the bladder has undergone many technological advances. Autologous urothelial cells have been used in animal models and have shown increased performance for ureteral reconstruction compared to unseeded grafts. However, since patients may lack a reliable source of native urothelial cells due to the nature of their specific bladder disease, autologous cells are not an ideal source clinically, and an alternate cell source must be explored. Adipose derived stem cells (ADSCs) are an attractive cell source for such regenerative medicine applications as they have been extensively studied for their multipotential differentiation, immunosuppressive properties, ease of ...


Electrochemical Enhancement Of Butanol Production And Xylose Consumption In Pure And Mixed Culture Fermentations, Jovan Popovic Dec 2015

Electrochemical Enhancement Of Butanol Production And Xylose Consumption In Pure And Mixed Culture Fermentations, Jovan Popovic

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The volatility of foreign and domestic petroleum markets has prompted initiatives for the development of alternative liquid energy carriers which have the capacity to accommodate our current transportation infrastructure. Butanol, which has an energy density similar to that of gasoline and can be produced through the fermentation of carbohydrates by solventogenic Clostridia, has been investigated as a supplement or direct replacement to gasoline. However, most butanol fermentations rely on glucose as a feedstock which is in direct competition with our food supply, and this requires the exploration of alternative fermentable substrates. This study investigates the use of electrochemical fermentation modifications ...


Robust Model Development For Evaluation Of Existing Structures, Saurabh Prabhu Dec 2015

Robust Model Development For Evaluation Of Existing Structures, Saurabh Prabhu

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In the context of scientific computing, validation aims to determine the worthiness of a model in supporting critical decision making. This determination must occur given the imperfections in the mathematical representation resulting from the unavoidable idealizations of physics phenomena. Uncertainty in parameter values furthers the validation problems due to the inevitable lack of information about material properties, boundary conditions, loads, etc. which must be taken into account in making predictions about structural response. The determination of worthiness then becomes assessing whether an unavoidably imperfect mathematical model, subjected to poorly known input parameters, can predict sufficiently well in its intended purpose ...


Designing Optical Properties In Infrared Glass, Benn Gleason Dec 2015

Designing Optical Properties In Infrared Glass, Benn Gleason

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Chalcogenide glasses (ChGs) are well-known for their attractive optical properties, such as high refractive index and transparency in across infrared wavelengths. ChGs also possess the ability to compositionally tune properties such as the refractive index, the thermo-optic coefficient, and other non-optical properties. Chalcogenide glasses with compositionally tailored physical and optical properties will provide optical designers with new materials necessary to create novel infrared imaging systems requiring new or expanded functionality. This dissertation has evaluated the relationship between glass composition, the resulting atomic structure, and resulting optical and thermo-optical properties, with specific focus on the infrared refractive index and the thermo-optic ...


Optimization Of Pyrochlore Catalysts For The Dry Reforming Of Methane, Felipe Polo Garzon Dec 2015

Optimization Of Pyrochlore Catalysts For The Dry Reforming Of Methane, Felipe Polo Garzon

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The conversion of methane into syngas (a mixture of CO and H2), which can be further converted into a variety of chemicals and particularly liquid fuels, is of growing importance given recent increases in methane production world-wide. Furthermore, since using CO2 as the co-feed offers many environmental advantages, dry reforming of methane (DRM, CH4 + CO2 ⇌ 2CO + 2H2) has received renewed attention. In recent years, experimentalists have shown that the Rh-substituted lanthanum zirconate pyrochlore (LRhZ) material is catalytically active for DRM, exhibits long-term thermal stability and resists deactivation; however, previous to this doctoral work, a detailed understanding of the ...


Understanding The Automotive Pedal Usage And Foot Movement Characteristics Of Older Drivers, Yubin Xi Dec 2015

Understanding The Automotive Pedal Usage And Foot Movement Characteristics Of Older Drivers, Yubin Xi

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The purpose of this study was to understand the pedal usage characteristics of older drivers in various driving tasks using an instrumented vehicle. This study stemmed from the prevalence of the pedal application errors (PAEs) and the older drivers’overrepresentation in crashes caused by PAEs.

With the population increasing and becoming older, it is estimated that in 2020 there will be 40 million drivers over the age of 65 in the United States. Compared with their younger counterparts, older drivers are facing declining cognitive and physical abilities, such as impaired vision, slower reaction time and diminishing range of limb motion ...


Developing Effective Ground And Space-Based Soil Moisture Sensing Techniques For Irrigating Cotton In Coastal Plain Soils, Xin Qiao Dec 2015

Developing Effective Ground And Space-Based Soil Moisture Sensing Techniques For Irrigating Cotton In Coastal Plain Soils, Xin Qiao

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Irrigation scheduling based on soil moisture sensor readings has gained popularity in the past few decades since it can enhance crop yield while saving water. Such method is limited since the representativeness of an individual soil moisture sensor measurement is questionable in a large field with variable soil type and texture. The optimum location of soil moisture sensors needs to be determined within such a production field for effective sensor-based irrigation scheduling. Therefore, the first object of this study was to investigate the optimum sensor location and the number of moisture sensors required for irrigating cotton in coastal plain soils ...


Design And Synthesis Of Polymer, Carbon And Composite Electrodes For High Energy And High Power Supercapacitors, Margarita Arcila-Velez Dec 2015

Design And Synthesis Of Polymer, Carbon And Composite Electrodes For High Energy And High Power Supercapacitors, Margarita Arcila-Velez

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Supercapacitors (SCs) are promising energy storage devices because they deliver energy faster than Li-ion batteries and store larger amounts of charge compared to dielectric capacitors. SCs are classified in electrical double layer capacitors (EDLCs) and pseudocapacitors, based on their charge storage mechanism. EDLCs store charge electrostatically, i.e. by physical charge separation. This mechanism limits the storable amount of energy to the available surface area of the electrode, typically made of carbon materials, but grants good cycling stability of the SC device. Pseudocapacitor electrodes, commonly made of conducting polymers or metal oxides, store charge faradaically, i.e. through redox reactions ...


A Laminated Ring On Elastic Foundation Model With Application To Analysis Of Tire-Road Contact, Chunjian Wang Dec 2015

A Laminated Ring On Elastic Foundation Model With Application To Analysis Of Tire-Road Contact, Chunjian Wang

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A deformable Ring on Elastic Foundation (REF) model has been widely used for modeling rotating structures such as gears, bearings and tires. This dissertation extends the existing work with three main contributions focusing on applications to tires: 1) The elastic foundation is endowed with unilateral stiffness, which leads to a nonlinear deformation dependent stiffness typical of some non-pneumatic tires; 2) The model of the deformable ring is extended from simple Timoshenko rings to a laminated orthotropic ring model, with bending, shear stiffness and extensibility in the internal layer, and transverse stiffness in the external layer; 3) Facilitated by the laminated ...


Synthesis And Characterization Of Oleophobic Fluorinated Polyester Films, Tugba Demir Dec 2015

Synthesis And Characterization Of Oleophobic Fluorinated Polyester Films, Tugba Demir

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The study presented in this dissertation is dedicated to the synthesis and characterization of oleophobic fluorinated polyester films. Specifically, the blending of oleophilic polyethylene terephthalate (PET) with low surface energy materials such as fluorinated polyesters has been used in order to fabricate oleophobic PET films. First, fluorinated polyesters (P(PF-oate-R)) possessing different end-groups (-COOH, -OH and -CF3) are synthesized via polycondensation reaction of isophthaloyl chloride with perfluoro ether alcohols. Then, they are solvent-blended with PET at various concentrations to obtain oleophobic polyester films of different compositions. In addition, the films are annealed to investigate the effect of annealing on surface ...


Characterizing The Effective Bandwidth Of Nonlinear Vibratory Energy Harvesters Possessing Multiple Stable Equilibria, Meghashyam Panyam Mohan Ram Dec 2015

Characterizing The Effective Bandwidth Of Nonlinear Vibratory Energy Harvesters Possessing Multiple Stable Equilibria, Meghashyam Panyam Mohan Ram

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In the last few years, advances in micro-fabrication technologies have lead to the development of low-power electronic devices spanning critical fields related to sensing, data transmission, and medical implants. Unfortunately, effective utilization of these devices is currently hindered by their reliance on batteries. In many of these applications, batteries may not be a viable choice as they have a fixed storage capacity and need to be constantly replaced or recharged. In light of such challenges, several novel concepts for micro-power generation have been recently introduced to harness, otherwise, wasted ambient energy from the environment and maintain these low-power devices. Vibratory ...


Integrated Coherent Combining Of Angled-Grating Broad-Area Lasers: Design, Fabrication And Characterization, Yunsong Zhao Dec 2015

Integrated Coherent Combining Of Angled-Grating Broad-Area Lasers: Design, Fabrication And Characterization, Yunsong Zhao

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In this thesis, we proposed, fabricated and demonstrated the coherent beam combining of angled-grating broad-area lasers. We have obtained the simultaneous coherent beam combining and single transverse mode operation completely on chip without any external phase control/components. Since the single transverse mode is the key to obtain diffraction-limit beam quality and high brightness, the proposed design is a good candidate for high power and high brightness applications. In the proposed coherently combined laser array, we use the angled-grating broad-area laser as the building block and overlap the adjacent emitters at one facet. The overlapped region becomes a 2D coupling ...


A Time-Efficient Strategy For Relay Selection And Link Scheduling In Wireless Communication Networks, Chenxi Qiu Dec 2015

A Time-Efficient Strategy For Relay Selection And Link Scheduling In Wireless Communication Networks, Chenxi Qiu

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Despite the unprecedented success and proliferation of wireless communication, sustainable reliability and stability among wireless users are still considered important issues in the underlying link protocols. Existing link-layer protocols, like ARQ [44] or HARQ [57,67] approaches are designed to achieve this goal by discarding a corrupted packet at the receiver and performing one or more retransmissions until the packet is successfully decoded or a maximum number of retransmission attempts is reached. These strategies suffer from degradation of throughput and overall system instability since packets need to be en/decode in every hop, leading to high burden for relay nodes ...


Configuration Management In Manufacturing And Assembly: Case Study And Enabler Development, Keith Phelan Dec 2015

Configuration Management In Manufacturing And Assembly: Case Study And Enabler Development, Keith Phelan

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The overall goal of this research is to improve the product configuration change management process. The increase in the demand for highly customizable products has led to many manufacturers using mass customization to meet the constantly changing demands of a wide consumer base. However, effectively managing the configurations can be difficult, especially in large manufacturers or for complex products with a large number of possible configurations. This is largely due to a combination of the scope of the configuration management system and the difficulty in understanding how changes to one element of a configuration can propagate through the configuration system ...