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- Creators: Barrett, The Honors College
- Creators: Aberle, James T., 1961-
- Resource Type: Text
Description
Semiconductor device scaling has kept up with Moore's law for the past decades and they have been scaling by a factor of half every one and half years. Every new generation of device technology opens up new opportunities and challenges and especially so for analog design. High speed and low gain is characteristic of these processes and hence a tradeoff that can enable to get back gain by trading speed is crucial. This thesis proposes a solution that increases the speed of sampling of a circuit by a factor of three while reducing the specifications on analog blocks and keeping the power nearly constant. The techniques are based on the switched capacitor technique called Correlated Level Shifting. A triple channel Cyclic ADC has been implemented, with each channel working at a sampling frequency of 3.33MS/s and a resolution of 14 bits. The specifications are compared with that based on a traditional architecture to show the superiority of the proposed technique.
ContributorsSivakumar, Balasubramanian (Author) / Farahani, Bahar Jalali (Thesis advisor) / Garrity, Douglas (Committee member) / Bakkaloglu, Bertan (Committee member) / Aberle, James T., 1961- (Committee member) / Arizona State University (Publisher)
Created2012
Description
The continuing advancement of modulation standards with newer generations of cellular technology, promises ever increasing data rate and bandwidth efficiency. However, these modulation schemes present high peak to average power ratio (PAPR) even after applying crest factor reduction. Being the most power-hungry component in the radio frequency (RF) transmitter, power amplifiers (PA) for infrastructure applications, need to operate efficiently at the presence of these high PAPR signals while maintaining reasonable linearity performance which could be improved by moderate digital pre-distortion (DPD) techniques. This strict requirement of operating efficiently at average power level while being capable of delivering the peak power, made the load modulated PAs such as Doherty PA, Outphasing PA, various Envelope Tracking PAs, Polar transmitters and most recently the load modulated balanced PA, the prime candidates for such application. However, due to its simpler architecture and ability to deliver RF power efficiently with good linearity performance has made Doherty PA (DPA) the most popular solution and has been deployed almost exclusively for wireless infrastructure application all over the world.
Although DPAs has been very successful at amplifying the high PAPR signals, most recent advancements in cellular technology has opted for higher PAPR based signals at wider bandwidth. This lead to increased research and development work to innovate advanced Doherty architectures which are more efficient at back-off (BO) power levels compared to traditional DPAs. In this dissertation, three such advanced Doherty architectures and/or techniques are proposed to achieve high efficiency at further BO power level compared to traditional architecture using symmetrical devices for carrier and peaking PAs. Gallium Nitride (GaN) based high-electron-mobility (HEMT) technology has been used to design and fabricate the DPAs to validate the proposed advanced techniques for higher efficiency with good linearity performance at BO power levels.
Although DPAs has been very successful at amplifying the high PAPR signals, most recent advancements in cellular technology has opted for higher PAPR based signals at wider bandwidth. This lead to increased research and development work to innovate advanced Doherty architectures which are more efficient at back-off (BO) power levels compared to traditional DPAs. In this dissertation, three such advanced Doherty architectures and/or techniques are proposed to achieve high efficiency at further BO power level compared to traditional architecture using symmetrical devices for carrier and peaking PAs. Gallium Nitride (GaN) based high-electron-mobility (HEMT) technology has been used to design and fabricate the DPAs to validate the proposed advanced techniques for higher efficiency with good linearity performance at BO power levels.
ContributorsRuhul Hasin, Muhammad (Author) / Kitchen, Jennifer (Thesis advisor) / Aberle, James T., 1961- (Committee member) / Bakkaloglu, Bertan (Committee member) / Kiaei, Sayfe (Committee member) / Arizona State University (Publisher)
Created2018
Description
The U.S. Navy and other amphibious military organizations utilize a derivation of the traditional side stroke called the Combat Side Stroke, or CSS, and tout it as the most efficient technique available. Citing its low aerobic requirements and slow yet powerful movements as superior to the traditionally-best front crawl (freestyle), the CSS is the go-to stroke for any operation in the water. The purpose of this thesis is to apply principles of Industrial Engineering to a real-world situation not typically approached from a perspective of optimization. I will analyze pre-existing data about various swim strokes in order to compare them in terms of efficiency for different variables. These variables include calories burned, speed, and strokes per unit distance, as well as their interactions. Calories will be measured by heart rate monitors, converting BPM to calories burned. Speed will be measured by stopwatch and observer. Strokes per unit distance will be measured by observer. The strokes to be analyzed include the breast stroke, crawl stroke, butterfly, and combat side stroke. The goal is to informally test the U.S. Navy's claim that the combat side stroke is the optimum stroke to conserve energy while covering distance. Because of limitations in the scope of the project, analysis will be done using data collected from literary sources rather than through experimentation. This thesis will include a design of experiment to test the findings here in practical study. The main method of analysis will be linear programming, followed by hypothesis testing, culminating in a design of experiment for future progress on this topic.
ContributorsGoodsell, Kevin Lewis (Author) / McCarville, Daniel R. (Thesis director) / Kashiwagi, Jacob (Committee member) / Industrial, Systems (Contributor) / Barrett, The Honors College (Contributor)
Created2014-12
Description
Lean and Green construction methodologies are prevalent in today's construction industry. Green construction implementation in buildings has progressed quickly due to the popularity and development of building rating systems, such as LEED, Green Globes, and the Living Building Challenge. Similarly, lean construction has become more popular as this philosophy often leads to efficient construction and improved owner satisfaction. Green construction is defined as using sustainable materials in the construction process to eliminate environmental degradation and ensure that material and equipment use aligns with the design intent and promotes efficient building performance. Lean construction is defined as a set of operational/systematic processes that reduce waste and eliminates defects in the project process throughout its lifecycle. This paper describes the implementation of Lean and Green construction processes to determine the trends that each methodology contributes to a project as well as how these methodologies synergize. The authors identified common elements of each methodology through semi-structured interviews with several construction industry professionals who had extensive experience with lean and green construction. Interviewees report lean and green construction philosophies are different "flavors" of the industry; however, interviewees also state if implemented together, these processes often result in a high-performance building.
ContributorsMaris, Kelsey Lynn (Co-author) / Parrish, Kristen (Co-author, Thesis director) / Olson, Patricia (Committee member) / Barrett, The Honors College (Contributor) / School of Sustainability (Contributor) / Del E. Webb Construction (Contributor)
Created2015-05
Description
Although the Leadership Scholarship Program has seen successful recruiting processes throughout changes in leadership of the program; the organization expressed a need for major overhaul to reevaluate the decisions of the process and to establish backing for those decisions. By asking current and alumni members of the program about what they would like to see in a future member of the program as well as which parts of the process they found most important, the qualities of a future member of the program could be established and weighted. The goals of the reevaluation were to help eliminate bias, discrepancies between applications with extremely different uncontrollable factors, define points of discrepancies, and establish organizational sustainability while achieving a 100% acceptance rate from offered students. Each of these goals was achieved through methods outlined in the LSP Selection Process Manual that was written as a result of this reevaluation. The manual also outlines ways to improve the process going forward.
ContributorsCassidy, Delilah R. (Author) / Kappes, Janelle (Thesis director) / Klinkner, Lara (Committee member) / Walter Cronkite School of Journalism and Mass Communication (Contributor) / Department of Marketing (Contributor) / Sandra Day O'Connor College of Law (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Balance of System Cost Analysis to Investigate Future Economic Competitiveness of Tandem Solar Cells
Description
As single junction silicon based solar cells approach their Shockley\u2014Queasier (SQ) conversion efficiency limits, tandem solar cells (TSC) provide an attractive prospect for higher efficiency cells. Although TSCs have been shown to be more efficient, their higher fabrication costs are a limiting factor for their economic competitiveness and large-scale integration in PV power systems. Current literature suggests that even with reduced costs of fabrication in the future, TSCs still offer no competitive benefit for integration in utility-scale systems and may yield minimal benefits only in places where area-related costs are high. This work investigates Balance of Systems (BoS) circumstances under which TSCs can attain economic viability in scenarios where the necessary technological advances are made to increase the efficiency of solar cells beyond the SQ limit.
ContributorsMugwisi, Ngoni (Author) / Holman, Zachary (Thesis director) / Phelan, Patrick (Committee member) / Industrial, Systems (Contributor) / Electrical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
This thesis focuses on the effects of an engine's induction and exhaust systems on vehicle fuel efficiency, along with the challenges accompanying improvement of this parameter. The aim of the project was to take an unconventional approach by investigating potential methods of increasing fuel economy via change of these systems outside the engine, as finding substantial gains via this method negates the need to alter engine architectures, potentially saving manufacturers research and development costs. The ultimate goal was to determine the feasibility of modifying induction and exhaust systems to increase fuel efficiency via reduction of engine pumping losses and increase in volumetric efficiency, with the hope that this research can aid others researching engine design in both educational and commercial settings. The first step toward achieving this goal was purchasing a test vehicle and performing experimental fuel efficiency testing on the unmodified, properly serviced specimen. A test route was devised to provide for a well-rounded fuel efficiency measurement for each trial. After stock vehicle trials were completed, the vehicle was to be taken out of service for a turbocharger system installation; unfortunately, challenges arose that could not be rectified within the project timeframe, and this portion of the project was aborted, to be investigated in the future. This decision was made after numerous fitment and construction issues with prefabricated turbo conversion parts were found, including induction and exhaust pipe size problems and misalignments, kit component packaging issues such as intercooler dimensions being too large, as well as manufacturing oversights, like failure to machine flanges flat for sealing and specification of incorrect flange sizes for mating components. After returning the vehicle to stock condition by removing the partially installed turbocharger system, the next step in the project was then installation of high-flow induction and exhaust systems on the test vehicle, followed by fuel efficiency testing using the same procedure as during the first portion of the experiment. After analysis of the quantitative and qualitative data collected during this thesis project, several conclusions were made. First, the replacement of stock intake and exhaust systems with high-flow variants did make for a statistically significant increase in fuel efficiency, ranging between 10 and 20 percent on a 95% confidence interval. Average fuel efficiency of the test vehicle rose from 21.66 to 24.90 MPG, an impressive increase considering the relative simplicity of the modifications. The tradeoff made was in noise produced by the vehicle; while the high-flow induction system only resulted in increased noise under very high-load circumstances, the high-flow exhaust system created additional noise under numerous load conditions, limiting the market applicability for this system. The most ideal vehicle type for this type of setup is sports/enthusiast cars, as increased noise is often considered a desirable addition to the driving experience; light trucks also represent an excellent application opportunity for these systems, as noise is not a primary concern in production of these vehicles. Finally, it was found that investing in high-flow induction and exhaust systems may not be a wise investment at the consumer level due to the lengthy payoff period, but for manufacturers, these systems represent a lucrative opportunity to increase fuel efficiency, potentially boosting sales and profits, as well as allowing the company to more easily meet federal CAFE standards in America. After completion of this project, there are several further research directions that could be taken to expand upon what was learned. The fuel efficiency improvements realized by installing high-flow induction and exhaust systems together on a vehicle were experimentally measured during testing; determining the individual effects of each of these systems installed on a vehicle would be the next logical research step within the same vein. Noise, vibration, and harshness increases after installing these systems were also noticed during experimental trials, so another future research direction could be an investigation into reducing these unwanted effects of high-flow systems. Finally, turbocharging to increase a vehicle's fuel efficiency, the original topic of this thesis, is another very important, contemporary issue in the world of improving vehicle fuel efficiency, and with manufacturers consistently moving toward turbocharged platform development, is a prime research topic in this area of study. In conclusion, the results from this thesis project exhibit that high-flow induction and exhaust systems can substantially improve a vehicle's fuel efficiency without modifying any internal engine components. This idea of improving a vehicle's fuel economy from outside the engine will ideally be further researched, such as by investigating turbocharger systems and their ability to improve fuel efficiency, as well as be developed and implemented by others in their educational projects and commercial products.
ContributorsCurl, Samuel Levi (Author) / Trimble, Steven (Thesis director) / Takahashi, Timothy (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
With the progression of different industries moving away from employing secretaries for business professionals and professors, there exists a void in the area of personal assistance. This problem has existing solutions readily available to replace this service, i.e. secretary or personal assistant, tend to range from expensive and useful to inexpensive and not efficient. This leaves a low cost niche into the market of a virtual office assistant or manager to display messages and to help direct people in obtaining contact information. The development of a low cost solution revolves around the software needed to solve the various problems an accessible and user friendly Virtual Interface in which the owner of the Virtual Office Manager/Assistant can communicate to colleagues who are at standby outside of the owner's office and vice versa. This interface will be allowing the owner to describe the status pertaining to their absence or any other message sent to the interface. For example, the status of the owner's work commute can be described with a simple "Running Late" phrase or a message like "Busy come back in 10 minutes". In addition, any individual with an interest to these entries will have the opportunity to respond back because the device will provide contact information. When idle, the device will show supplemental information such as the owner's calendar and name. The scope of this will be the development and testing of solutions to achieve these goals.
ContributorsOffenberger, Spencer Eliot (Author) / Kozicki, Michael (Thesis director) / Goryll, Michael (Committee member) / Electrical Engineering Program (Contributor) / Computer Science and Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
This thesis describes the design process used in the creation of a two stage cellular power amplifier. A background for understanding amplifier linearity, device properties, and ACLR estimation is provided. An outline of the design goals is given with a focus on linearity with high efficiency. The full design is broken into smaller elements which are discussed in detail. The main contribution of this thesis is the description of a novel interstage matching network topology for increasing efficiency. Ultimately the full amplifier design is simulated and compared to the measured results and design goals. It was concluded that the design was successful, and used in a commercially available product.
ContributorsSpivey, Erin (Author) / Aberle, James T., 1961- (Thesis advisor) / Kitchen, Jennifer (Committee member) / Ozev, Sule (Committee member) / Arizona State University (Publisher)
Created2012
Description
The Performance Based Studies Research Studies Group (PBSRG) at Arizona State University (ASU) has been studying the cause of increased cost and time in construction and other projects for the last 20 years. Through two longitudinal studies with a group of owners in the state of Minnesota (400 tests over six years) and the US Army Medical Command (400 tests over four years), the client/buyer has been identified as the largest risk and source of project cost and time deviations. This has been confirmed by over 1,500 tests conducted over the past 20 years. The focus of this research effort is to analyze the economic and performance impact of a delivery process of construction called the Job Order Contracting (JOC) process, to evaluate the value (in terms of time, cost, and customer satisfaction) achieved when utilizing JOC over other traditional methods to complete projects. JOC's strength is that it minimizes the need for the owner to manage, direct and control (MDC) through a lengthy traditional process of design, bid, and award of a construction contract. The study identifies the potential economic savings of utilizing JOC. This paper looks at the results of an ongoing study surveying eight different public universities. The results of the research show that in comparison to more traditional models, JOC has large cost savings, and is preferable among most owners who have used multiple delivery systems.
ContributorsLi, Hao (Author) / Kashiwagi, Dean (Thesis director) / Kashiwagi, Jacob (Committee member) / Industrial, Systems (Contributor) / Department of Information Systems (Contributor) / Barrett, The Honors College (Contributor)
Created2015-12