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Electronic Theses and Dissertations

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Articles 2011 - 2040 of 4180

Full-Text Articles in Engineering

Pressurized Metal Bellows Shock Absorber For Space Applications., John Trautwein Jan 2015

Pressurized Metal Bellows Shock Absorber For Space Applications., John Trautwein

Electronic Theses and Dissertations

Numerous spacecraft designs exist for exploring the surfaces of planetary bodies and each have their own advantages and disadvantages. All successful landings have been made by stationary landers or wheeled rovers that rely on one-time use mechanisms, such as crushable aluminum honeycomb shock absorbers or inflatable airbags, to reduce shock loading to the spacecraft during landing. The stationary lander is the simplest type of lander, but can only take data from one location. Wheeled rovers add complexity in exchange for mobility to explore different locations. Rovers are limited by the terrain they can traverse; rovers becoming stuck have ended missions. …

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Performance Optimization Of Lateral-Mode Thin-Film Piezoelectric-On-Substrate Resonant Systems, Hedy Fatemi Jan 2015

Performance Optimization Of Lateral-Mode Thin-Film Piezoelectric-On-Substrate Resonant Systems, Hedy Fatemi

Electronic Theses and Dissertations

The main focus of this dissertation is to characterize and improve the performance of thin-film piezoelectric-on-substrate (TPoS) lateral-mode resonators and filters. TPoS is a class of piezoelectric MEMS devices which benefits from the high coupling coefficient of the piezoelectric transduction mechanism while taking advantage of superior acoustic properties of a substrate. The use of lateral-mode TPoS designs allows for fabrication of dispersed-frequency filters on a single substrate, thus significantly reducing the size and manufacturing cost of devices. TPoS filters also offer a lower temperature coefficient of frequency, and better power handling capability compared to rival technologies all in a very …

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Applications Of Computer Vision Technologies Of Automated Crack Detection And Quantification For The Inspection Of Civil Infrastructure Systems, Liuliu Wu Jan 2015

Applications Of Computer Vision Technologies Of Automated Crack Detection And Quantification For The Inspection Of Civil Infrastructure Systems, Liuliu Wu

Electronic Theses and Dissertations

Many components of existing civil infrastructure systems, such as road pavement, bridges, and buildings, are suffered from rapid aging, which require enormous nation's resources from federal and state agencies to inspect and maintain them. Crack is one of important material and structural defects, which must be inspected not only for good maintenance of civil infrastructure with a high quality of safety and serviceability, but also for the opportunity to provide early warning against failure. Conventional human visual inspection is still considered as the primary inspection method. However, it is well established that human visual inspection is subjective and often inaccurate. …

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Base Flow Recession Analysis For Streamflow And Spring Flow, Debapi Ghosh Jan 2015

Base Flow Recession Analysis For Streamflow And Spring Flow, Debapi Ghosh

Electronic Theses and Dissertations

Base flow recession curve during a dry period is a distinct hydrologic signature of a watershed. The base flow recession analysis for both streamflow and spring flow has been extensively studied in the literature. Studies have shown that the recession behaviors during the early stage and the late stage are different in many watersheds. However, research on the transition from early stage to late stage is limited and the hydrologic control on the transition is not completely understood. In this dissertation, a novel cumulative regression analysis method is developed to identify the transition flow objectively for individual recession events in …

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Propagation Of Unit Location Uncertainty In Dense Storage Environments, Patrick Reilly Jan 2015

Propagation Of Unit Location Uncertainty In Dense Storage Environments, Patrick Reilly

Electronic Theses and Dissertations

Effective space utilization is an important consideration in logistics systems and is especially important in dense storage environments. Dense storage systems provide high-space utilization; however, because not all items are immediately accessible, storage and retrieval operations often require shifting of other stored items in order to access the desired item, which results in item location uncertainty when asset tracking is insufficient. Given an initial certainty in item location, we use Markovian principles to quantify the growth of uncertainty as a function of retrieval requests and discover that the steady state probability distribution for any communicating class of storage locations approaches …

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Sustainability Assessment Of A Municipal Utility Complex: A System Of Systems Approach, Tarek Fahmy Jan 2015

Sustainability Assessment Of A Municipal Utility Complex: A System Of Systems Approach, Tarek Fahmy

Electronic Theses and Dissertations

Construction of municipal utility complexes has to support continuing population growth, economic development, and a widespread of social interest in environmental preservation. Municipalities face challenges in designing, constructing, and operating environmentally sustainable utility complexes, and their primary goal in developing such a complex is to minimize the environmental impact resulting from energy production and waste treatment (both liquid and solid), management, and disposal. However, decision and policy makers lack a system of systems approach that takes into account multiple interdependent systems comprised of the functional system (infrastructure, facilities, operations within the complex…), the economic system, the social/cultural system, and the …

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Exploring 3d User Interface Technologies For Improving The Gaming Experience, Arun Kulshreshth Jan 2015

Exploring 3d User Interface Technologies For Improving The Gaming Experience, Arun Kulshreshth

Electronic Theses and Dissertations

3D user interface technologies have the potential to make games more immersive & engaging and thus potentially provide a better user experience to gamers. Although 3D user interface technologies are available for games, it is still unclear how their usage affects game play and if there are any user performance benefits. A systematic study of these technologies in game environments is required to understand how game play is affected and how we can optimize the usage in order to achieve better game play experience. This dissertation seeks to improve the gaming experience by exploring several 3DUI technologies. In this work, …

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Exploration And Development Of Crash Modification Factors And Functions For Single And Multiple Treatments, Juneyoung Park Jan 2015

Exploration And Development Of Crash Modification Factors And Functions For Single And Multiple Treatments, Juneyoung Park

Electronic Theses and Dissertations

Traffic safety is a major concern for the public, and it is an important component of the roadway management strategy. In order to improve highway safety, extensive efforts have been made by researchers, transportation engineers, Federal, State, and local government officials. With these consistent efforts, both fatality and injury rates from road traffic crashes in the United States have been steadily declining over the last six years (2006~2011). However, according to the National Highway Traffic Safety Administration (NHTSA, 2013), 33,561 people died in motor vehicle traffic crashes in the United States in 2012, compared to 32,479 in 2011, and it …

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A Framework For Safety Training Using Virtual Reality Software, Rana Riad Jan 2015

A Framework For Safety Training Using Virtual Reality Software, Rana Riad

Electronic Theses and Dissertations

Safety training is a vital component to the well-being of individuals in all industries. With technology advancing at the current pace, conventional training methods are no longer the most effective way to communicate information. There is a strong need for safety training that incorporates new methods and forms of communication to obtain higher levels of comprehension. Virtual reality systems offer a highly customizable and interactive form of delivering information to users. This research addresses major gaps in the field of safety training using virtual reality systems and provides a design framework for creating a virtual safety-training system. A model for …

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Mathematical Modeling Of Carbon Removal In The A-Stage Activated Sludge System, Thomas Nogaj Jan 2015

Mathematical Modeling Of Carbon Removal In The A-Stage Activated Sludge System, Thomas Nogaj

Electronic Theses and Dissertations

This research developed a dynamic activated sludge model (ASM) to better describe the overall removal of organic substrate, quantified as chemical oxygen demand (COD), from A-stage high rate activated sludge (HRAS) systems. This dynamic computer model is based on a modified ASM1 (Henze et al., 2000) model. It was determined early in the project that influent soluble COD, which is normally represented by a single state variable in ASM1, had to be subdivided into two state variables (SBs and SBf, or slow and fast fractions) to simulate the performance of A-stage systems. Also, the addition of state variables differentiating colloidal …

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Development Of Velocity Profile Generating Screens For Gas Turbine Components, Joseph Tate Jan 2015

Development Of Velocity Profile Generating Screens For Gas Turbine Components, Joseph Tate

Electronic Theses and Dissertations

Laboratory experiments on components of complex systems such as gas turbines require many conditions to be met. Requirements to be met in order to simulate real world conditions include inlet flow conditions such as velocity profile, Reynold's number, and temperature. The methodology to be introduced designs a velocity profile generating screen to match real world conditions through the use of perforated plates. The velocity profile generating screen is an array of jets arranged in a manner to produce sections of different solidities, a ratio of area that obstructs fluid flow compared to that of the total area. In an effort …

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The Investigation Of Okhissa Dam Using A Real-Time Monitoring System, Corey Alexander Hamil Jan 2015

The Investigation Of Okhissa Dam Using A Real-Time Monitoring System, Corey Alexander Hamil

Electronic Theses and Dissertations

According to the National Inventory of Dams (NID), the United States has approximately 87,000 dams. Many of these dams are more than 50 years old and need to be investigated to ensure their safety to the public. A real time monitoring system can obtain a more reliable evaluation of the dam’s performance as well as serve as an early warning system to inform officials of a dam’s condition. Okhissa Dam was selected for investigation using a real-time monitoring system. Okhissa Dam is located in a region that contains both a phreatic aquifer and a confined aquifer. Prior to this investigation …

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Dynamic Mechanical Analysis And High Strain-Rate Energy Absorption Characteristics Of Vertically Aligned Carbon Nanotube (Vacnt) Reinforced Woven Fiber-Glass Composites, Kiyun Kim Jan 2015

Dynamic Mechanical Analysis And High Strain-Rate Energy Absorption Characteristics Of Vertically Aligned Carbon Nanotube (Vacnt) Reinforced Woven Fiber-Glass Composites, Kiyun Kim

Electronic Theses and Dissertations

No abstract provided.

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Fiber Compaction And Wetout In Tapered Resin Injection Pultrusion Manufacturing, Naveen Babu Masuram Jan 2015

Fiber Compaction And Wetout In Tapered Resin Injection Pultrusion Manufacturing, Naveen Babu Masuram

Electronic Theses and Dissertations

Pultrusion is a continuous process for manufacturing composite materials with constant cross section. Reinforced fibers are pulled through a resin, possibly folloby a separate injection chamber preforming system, and into a heated die, where the resin undergoes complete wetout. Thus the required pultruded composite is obtained in the desired profile. The main objective of this research is to present a numerical model employing the finite volume technique to simulate the resin flow in a tapered injection chamber through the fiber reinforcement when compaction of the fiber reinforcement is taken into account. The numerical model predicts the impact of design and …

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Some Experimental Investigation On Effect Of Light And Vibration On Nano Coated Piezo For Energy Harvesting, Abhay Sharma Jan 2015

Some Experimental Investigation On Effect Of Light And Vibration On Nano Coated Piezo For Energy Harvesting, Abhay Sharma

Electronic Theses and Dissertations

PZT is a promising piezoelectric ceramic material which has a wide range of applications in a variety of fields such as acoustic sensors and transducers, electrical switches, medical instrumentation, artificial sensitive skin in robotics, automotive detection on roads, nondestructive testing , structural health monitoring and as a biocompatible material. In this research a cantilever based multi energy harvester was developed to maximize the power output of PZT sensor. Nano mixtures containing graphene, ferrofluid nanoparticle (FNP) and ZnO nano particles were used to enhance the piezoelectric and photovoltaic output of the sensor. The samples were tested under different energy conditions to …

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Carbon Dioxide Capture With Amine Functionlized Graphene Oxide, Renee Zeleszki Jan 2015

Carbon Dioxide Capture With Amine Functionlized Graphene Oxide, Renee Zeleszki

Electronic Theses and Dissertations

Abstract: amine functionalized graphene oxide was used as sorbent in order to achieve carbon dioxide capture. In this study, micro size graphite flakes was prepared according to modified hummers method and "hummers' method with additional kmno4." Graphene oxide was then functionalized with ethylenediamine (eda). Different purification methods for graphene oxide were studied as well as different functionalization method times. Graphite oxide and functionalized graphene oxide has been analyzed with fourier transform infrared spectroscopy (ftir) for chemical structure. Thermal gravimetric analysis (tga) was used to test co2 capture capacity. Functionalized graphene oxide that has been purified with 30 washes via centrifuge …

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Computational Finite Element Analysis Of Extreme Loading Response Of Structural Insulated Panel (Sip) Building Subsystems, Kimberly Anne Tanner Jan 2015

Computational Finite Element Analysis Of Extreme Loading Response Of Structural Insulated Panel (Sip) Building Subsystems, Kimberly Anne Tanner

Electronic Theses and Dissertations

In the reconstruction after Hurricane Katrina, the Mississippi Emergency Management Agency (mema) investigated of the possibility of utilizing structural insulated panel (sip) construction for hurricane "cottages" that would be resistant to a category 3 hurricane through a joint project with a local architect, Bruce Tolar, and FMS Engineering, LLC, Mobile, Alabama. The connections between the sip panels, including a cam-locking device comto sip panel construction, were identified as vulnerable under high velocity wind loads. At that time, there were no published guidelines for performing a computational finite element analysis of the sip system, and thus it was not possible to …

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Empirical Modeling Of Piping Along Mississippi River Levees In Southwestern Illinois, Rebecca F. Shields Jan 2015

Empirical Modeling Of Piping Along Mississippi River Levees In Southwestern Illinois, Rebecca F. Shields

Electronic Theses and Dissertations

No abstract provided.

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A Study On The Analyzing Priority Of Limiting Factors In Live, Virtual, And Constructive (Lvc) Simulation Interoperability Using Analytic Hierarchy Process (Ahp) Method, Youngkun Yoo Jan 2015

A Study On The Analyzing Priority Of Limiting Factors In Live, Virtual, And Constructive (Lvc) Simulation Interoperability Using Analytic Hierarchy Process (Ahp) Method, Youngkun Yoo

Electronic Theses and Dissertations

Each Live, Virtual, and Constructive (LVC) simulation model has been developed and used with many benefits. When system developers created each simulation model, focused on specific standards to fit to their own respective purposes. Consequently, there have been interoperability issues among simulation models that have many limitations. To be specific, despite various efforts to achieve and maintain complete interoperability in LVC simulation environment, substantial limiting factors have remained in technical and managerial fields. Thus, analyzing and prioritizing limiting factors in LVC simulation is the effective way to solve interoperability problems while saving budget and time. The purpose of this research …

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The Design, Implementation, And Refinement Of Wait-Free Algorithms And Containers, Steven Feldman Jan 2015

The Design, Implementation, And Refinement Of Wait-Free Algorithms And Containers, Steven Feldman

Electronic Theses and Dissertations

My research has been on the development of concurrent algorithms for shared memory systems that provide guarantees of progress. Research into such algorithms is important to developers implementing applications on mission critical and time sensitive systems. These guarantees of progress provide safety properties and freedom from many hazards, such as dead-lock, live-lock, and thread starvation. In addition to the safety concerns, the fine-grained synchronization used in implementing these algorithms promises to provide scalable performance in massively parallel systems. My research has resulted in the development of wait-free versions of the stack, hash map, ring buffer, vector, and a multi-word compare-and-swap …

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Damage Detection Methodologies For Structural Health Monitoring Of Thin-Walled Pressure Vessels, Arturo Modesto Jan 2015

Damage Detection Methodologies For Structural Health Monitoring Of Thin-Walled Pressure Vessels, Arturo Modesto

Electronic Theses and Dissertations

There is a need in exploring structural health monitoring technologies for the composite structures particularly aged Composite Overwrapped Pressure Vessels (COPVs) for the current and future implementation of COPVs for space missions. In this study, the research was conducted in collaboration with NASA Kennedy Space Center and also NASA Marshall Space and Flight Center engineers. COPVs have been used to store inert gases like helium (for propulsion) and nitrogen (for life support) under varying degrees of pressure onboard the orbiter since the beginning of the Space Shuttle Program. After the Columbia accident, the COPVs were re-examined and different studies (e.g. …

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Spray Deposition Modeling Of Carbon Nano-Inks, John Sparkman Jan 2015

Spray Deposition Modeling Of Carbon Nano-Inks, John Sparkman

Electronic Theses and Dissertations

Carbon nanopaper (CNP) exhibits qualities that are desirable for a number of applications such as flame retardancy, lightning protection, and flexible printed circuit boards. CNP has become a desired engineering material in many important sectors of industries such as space, automotive, aviation, and military. However the production of consistent thicknesses and dispersion remains a challenge for practical use. Most of the standard methods of production do not allow for continuous applications or digital fabrication of the CNP. In this work, CNP is produced two different ways that allows for continuous production and digital fabrication. The continuous CNP making technique uses …

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Transverse Mode Selection And Brightness Enhancement In Laser Resonators By Means Of Volume Bragg Gratings, Brian Anderson Jan 2015

Transverse Mode Selection And Brightness Enhancement In Laser Resonators By Means Of Volume Bragg Gratings, Brian Anderson

Electronic Theses and Dissertations

The design of high power lasers requires large mode areas to overcome various intensity driven nonlinear effects. Increasing the aperture size within the laser can overcome these effects, but typically result in multi-transverse mode output and reduced beam quality, limiting the brightness of the system. As one possible solution, the angular selectivity of a diffractive optical element is proposed as a spatial filter, allowing for the design of compact high brightness sources not possible with conventional methods of transverse mode selection. This thesis explores the angular selectivity of volume Bragg gratings (VBGs) and their use as spatial transverse mode filters …

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Sustainable Material Solution For Flexible Pavements; Performance Evaluation And Impact Assessment Of Utilizing Multiple Recycled Materials In Hma, Behnam Golestani Jan 2015

Sustainable Material Solution For Flexible Pavements; Performance Evaluation And Impact Assessment Of Utilizing Multiple Recycled Materials In Hma, Behnam Golestani

Electronic Theses and Dissertations

The demand for pollution-free and recyclable engineering materials has been increased as the cost of energy and environmental concerns have risen. Green material design can lead to better environmental quality and sustainability of civil infrastructure. Road construction is one of the largest consumers of natural resources. Beneficial utilization of recycled materials can result in an important opportunity to save the mining and use of virgin materials, to preserve energy, and to save landfill space. Two main research questions addressed in this study are: (1) How much pollution, energy, natural resources, time and money can be salvaged by applying recycling materials …

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Nano And Nanostructured Materials For Optical Applications, Panit Chantharasupawong Jan 2015

Nano And Nanostructured Materials For Optical Applications, Panit Chantharasupawong

Electronic Theses and Dissertations

Nano and nanostructured materials offer unique physical and chemical properties that differ considerably from their bulk counterparts. For decades, due to their fascinating properties, they have been extensively explored and found to be beneficial in numerous applications. These materials are key components in many cutting-edge optic and photonic technologies, including photovoltaics, waveguides and sensors. In this dissertation, the uses of nano and nanostructured materials for optical applications are investigated in the context of optical limiting, three dimensional displays, and optical sensing. Nanomaterials with nonlinear optical responses are promising candidates for self-activating optical limiters. In the first part of this study, …

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Assessing Approximate Arithmetic Designs In The Presence Of Process Variations And Voltage Scaling, Adnan Aquib Naseer Jan 2015

Assessing Approximate Arithmetic Designs In The Presence Of Process Variations And Voltage Scaling, Adnan Aquib Naseer

Electronic Theses and Dissertations

As environmental concerns and portability of electronic devices move to the forefront of priorities, innovative approaches which reduce processor energy consumption are sought. Approximate arithmetic units are one of the avenues whereby significant energy savings can be achieved. Approximation of fundamental arithmetic units is achieved by judiciously reducing the number of transistors in the circuit. A satisfactory tradeoff of energy vs. accuracy of the circuit can be determined by trial-and-error methods of each functional approximation. Although the accuracy of the output is compromised, it is only decreased to an acceptable extent that can still fulfill processing requirements. A number of …

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Motor Imagery Classification Using Sparse Representation Of Eeg Signals, Pouria Saidi Jan 2015

Motor Imagery Classification Using Sparse Representation Of Eeg Signals, Pouria Saidi

Electronic Theses and Dissertations

The human brain is unquestionably the most complex organ of the body as it controls and processes its movement and senses. A healthy brain is able to generate responses to the signals it receives, and transmit messages to the body. Some neural disorders can impair the communication between the brain and the body preventing the transmission of these messages. Brain Computer Interfaces (BCIs) are devices that hold immense potential to assist patients with such disorders by analyzing brain signals, translating and classifying various brain responses, and relaying them to external devices and potentially back to the body. Classifying motor imagery …

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An On-Orbit Calibration Procedure For Spaceborne Microwave Radiometers Using Special Spacecraft Attitude Maneuvers, Spencer Farrar Jan 2015

An On-Orbit Calibration Procedure For Spaceborne Microwave Radiometers Using Special Spacecraft Attitude Maneuvers, Spencer Farrar

Electronic Theses and Dissertations

This dissertation revisits, develops, and documents methods that can be used to calibrate spaceborne microwave radiometers once in orbit. The on-orbit calibration methods discussed within this dissertation can provide accurate and early results by utilizing Calibration Attitude Maneuvers (CAM), which encompasses Deep Space Calibration (DSC) and a new use of the Second Stokes (SS) analysis that can provide early and much needed insight on the performance of the instrument. This dissertation describes pre-existing and new methods of using DSC maneuvers as well as a simplified use of the SS procedure. Over TRMM's 17 years of operation it has provided invaluable …

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A Gpu Powered Mobile Ar Navigation System, Mengshen Zhao Jan 2015

A Gpu Powered Mobile Ar Navigation System, Mengshen Zhao

Electronic Theses and Dissertations

This thesis presents a real-time Augmented Reality Navigation System(ARNavi) on Android smartphone that leverages the parallel computing power of mobile GPUs. Unlike conventional navigation systems, our proposed ARNavi augments navigation information onto real scene video streaming from device camera in real-time. To achieve this goal, we implement and accelerate compute intensive part of applications using OpenCL on GPU integrated on mobile Application Processor (AP). The contributions of this thesis are three-fold. First, we propose new lane detection algorithm and prediction mechanism based on geometric coordinates. The result shows that these two algorithms are fast and accurate. Second, we port and …

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Modeling Roughness Of Rock Discontinuity Surfaces, Christopher Pickering Jan 2015

Modeling Roughness Of Rock Discontinuity Surfaces, Christopher Pickering

Electronic Theses and Dissertations

The aim of this thesis is to propose a new methodology of quantifying the rock discontinuity condition of roughness through the physically based modeling approach of signal analysis. The development of this method came about after investigation into the use of qualitative categorizations of roughness from the RMR rating system within rock engineering system matrices. In an attempt to assign significant values to these generalized qualitative descriptions, the standard joint roughness coefficient (JRC) profiles were initially examined through basic measurements, such as aperture and ramp angle. Following these initial measurements and identification of inconsistencies in the wave parameters of the …

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