2013 Research Day Abstract Listing

Highlighting and recognizing graduate and undergraduate student research throughout all disciplines at the University of Northern Colorado. Abstracts of oral and poster presentations from student researchers, presented at UNC\u27s Annual Research Conference during Academic Excellence Week

Optimum frequency modulation receivers

Optimization of receivers for demodulating FM SIGNAL corrupted by Gaussian noise, and solution to maximum likelihood equatio

Analyses of Bicycle and Pedestrian Trail Traffic: New Tools for Modeling User Expenditures and Demand

University of Minnesota MURP thesis. August 2017. Major: Urban and Regional Planning. Advisor: Greg Lindsey. 1 computer file (PDF); x, 93 pages.Despite the importance of multi-use trails in urban non-motorized transportation networks, transportation planners, engineers, and trail managers lack tools for describing economic activity associated with local trail use and for predicting bicycle and pedestrian demand for trails. New tools are needed to plan and prioritize investments in new facilities and to inform management and maintenance of trail infrastructure. Among other needs, they need tools to predict (1) expenditures by local users to support local economic development initiatives and assess neighborhood effects of proposals for trail development and (2) trail traffic demand for optimizing investments and managing maintenance of systems and facilities. This thesis responds to these needs and augments the burgeoning literature on trail traffic analysis by developing models of trail-related expenditures and mode-specific trail demand models. From the expenditures by local users side, using the results of intercept surveys completed by 1,282 trail users on the Central Ohio Greenway trail network in 2014, this thesis estimates the probabilities and patterns that different types of trail users will make expenditures. Approximately one-fifth of trail users reported spending between US$15 and US$20 for food, drink, and other incidental items. Across all trail users the average expenditure by individuals is about US$3 per visit. All else equal, cyclists are more than twice as likely than other users to report expenditures. Users visiting trails principally for recreation are 53% more likely to spend, while users visiting trails mainly for exercise were about 19% less likely. Both longer trips to and on the trails are associated with higher spending. From the trail traffic demand side, this thesis employs trail traffic volumes recorded at 15-minute intervals for 32 multi-use trails located in 13 urban areas across the United States from January 1, 2014 through February 16, 2016. The results of analyses indicate (1) daily trail traffic varies substantially – over three orders of magnitude – across the monitoring stations included in the study; (2) daily trail traffic is highly correlated with weather, and the parabola form of weather parameters works well for modeling variables such as temperature, where trail use is associated with warmer temperatures, but only up to a point at which higher temperatures then decrease use; (3) bicyclists and pedestrians respond differently to variations in weather, and their responses vary both within and across regions; (4) with only a few exceptions, average daily pedestrians (ADP) and average daily bicyclists (ADB) are correlated with different variables, and the magnitude of effects of variables that are the same varies significantly between the two modes; (5) the mean relative percentage error (MRPE) for bicyclist, pedestrian, and mixed-mode demand models, respectively, are 65.4%, 85.3%, and 45.9%; (6) although using multimodal monitoring networks enables us to juxtapose the bicyclist demand with pedestrian demand, there is not a significant improvement in predicting total demand using multimodal sensors; (7) a new post-validation procedure improves the demand models, reducing the MRPE of bicyclist, pedestrian, and mixed-mode models by 27.2%, 32.1%, and 14.1%. Transportation planners, engineers, and trail managers can use these results to estimate the effects of weather and climate on trail traffic and to plan and manage facilities more effectively. The developed models also can be used in practical applications such as selection of route corridors and prioritization of investments where order-of-magnitude estimates suffice

Disseny microelectrnic de circuits discriminadors de polsos pel detector LHCb

The aim of this thesis is to present a solution for implementing the front end system of the Scintillator Pad Detector (SPD) of the calorimeter system of the LHCb experiment that will start in 2008 at the Large Hadron Collider (LHC) at CERN. The requirements of this specific system are discussed and an integrated solution is presented, both at system and circuit level. We also report some methodological achievements. In first place, a method to study the PSRR (and any transfer function) in fully differential circuits taking into account the effect of parameter mismatch is proposed. Concerning noise analysis, a method to study time variant circuits in the frequency domain is presented and justified. This would open the possibility to study the effect of 1/f noise in time variants circuits. In addition, it will be shown that the architecture developed for this system is a general solution for front ends in high luminosity experiments that must be operated with no dead time and must be robust against ballistic deficit

An asynchronous,low-power architecture for interleaved neural stimulation, using envelope and phase information

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2007.Includes bibliographical references (p. 122-124).This thesis describes a low-power cochlear-implant processor chip and a charge-balanced stimulation chip that together form a complete processing-and-stimulation cochlear-implant system. The processor chip uses a novel Asynchronous Interleaved Stimulation (AIS) algorithm that preserves phase and amplitude cues in its spectral input while simultaneously minimizing electrode interactions and lowering average stimulation power per electrode. The stimulator chip obviates the need for large D.C. blocking capacitors in neural implants to achieve highly precise charge-balanced stimulation, thus lowering the size and cost of the implant. Thus, this thesis suggests that significant performance, power and cost improvements in the current generation of cochlear implants may be simultaneously possible. The 16-channel ~90 square mm AIS processor chip was built in a 1.5[mu]m VLSI process and consumed 107[mu]W of power over and above that of its analog spectral processing front end, which consumed 250gtW and which has been previously described. The AIS processor was found to faithfully mimic MATLAB implementations of the AIS algorithm. Two perceptual tests of the AIS algorithm with normal-hearing listeners verified that AIS signal reconstructions enabled better melody and speech recognition in noise than traditional envelope-only vocoder simulations of cochlear-implant processing. The average firing rate of the AIS processor was found to be significantly lower than in traditional synchronous stimulators, suggesting that the AIS algorithm and processor can potentially save power and improve hearing performance in cochlear-implant users. The stimulator chip was built in a 0.7glm high-voltage VLSI process and performed dynamic current balancing followed by a shorting phase.(cont.) It achieved <6nA of average DC current error, well below the targeted safety limit of 25nA for cochlear-implant patients. On +6 and -9V rails, the power consumption of a single channel of this chip was 47[mu]W when biasing power is shared by 16 channels. It puts out a charge-balanced stimulation pulse whenever it receives an asynchronous input signal from an AIS processor encoding phase information and 7-bit amplitude information, thus making the AIS processor chip and stimulator chip fully compatible in the cochlear-implant system. The AIS algorithm and charge-balancing circuits described in this work may be useful in other nerve-stimulation prosthetics where good fidelity in input-information encoding, minimization of electrode interactions, low-power strategies for stimulation, and compact charge-balanced stimulation are also important.by Ji-Jon Sit.Ph.D

Improved micro-contact resistance model that considers material deformation, electron transport and thin film characteristics

This paper reports on an improved analytic model forpredicting micro-contact resistance needed for designing microelectro-mechanical systems (MEMS) switches. The originalmodel had two primary considerations: 1) contact materialdeformation (i.e. elastic, plastic, or elastic-plastic) and 2) effectivecontact area radius. The model also assumed that individual aspotswere close together and that their interactions weredependent on each other which led to using the single effective aspotcontact area model. This single effective area model wasused to determine specific electron transport regions (i.e. ballistic,quasi-ballistic, or diffusive) by comparing the effective radius andthe mean free path of an electron. Using this model required thatmicro-switch contact materials be deposited, during devicefabrication, with processes ensuring low surface roughness values(i.e. sputtered films). Sputtered thin film electric contacts,however, do not behave like bulk materials and the effects of thinfilm contacts and spreading resistance must be considered. Theimproved micro-contact resistance model accounts for the twoprimary considerations above, as well as, using thin film,sputtered, electric contact

Seismic Characterization of Fracture Rock Fabric in Mississippian Limestone, Payne County Oklahoma

Fractures are pre-existing planes of weaknesses. They play a critical role in determining the production potential of reservoirs that are developed through lateral drilling and fracture stimulation, such as the Mid-Continent Mississippian limestone. Estimation of fracture density using geophysical methods, such as seismic, is desirable, but extremely challenging at the same time. Conventionally, a single seismic attribute such as amplitude or coherency has been proxy for fractures with limited success. This thesis demonstrates that multiple seismic attributes can be combined using statistical methods to yield a reliable fracture density map.Geolog