Collection Description

Collection of student theses and dissertations from as early as 1939, but mainly from 2010 to present.

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3π/8 offset 8PSK modulation in EDGE GSM
Includes bibliographical references (p. 45), This thesis is about the EDGE GSM technology. The study starts with the understanding of what kind of modulation techniques are used in this technology. EDGE GSM is the next step in the evolution of GSM and IS-136. The aim of the new technology is to increase data transmission rates and spectrum efficiency and to facilitate new applications and increased capacity for mobile use. EDGE GSM is a method to increase the data rates on the radio link for GSM which uses 8 phase shift keying (8PSK) for modulation and coding schemes. EDGE GSM produces a 3-bit word for every change in carrier phase. This effectively triples the gross data rate offered by GSM. In 8-PSK modulation, the trajectory of the modulating data (I and Q) goes through zero origin. Where the trajectory crosses the origin, non linearity at low power regions will distort the signal and, hence, produce spectral re-growth. To overcome this situation, it would be useful if the origin somehow could be avoided for the modulating data. The introduction of 3π/8 offset to the 8-PSK with a higher spectral efficiency requires new and more complex algorithms for the equalization part as well as for the coding and decoding part. The transmitted signal once it has been filtered is difficult to interpret. Hence, Error vector magnitude is used to assess the received signal. In addition to 8-PSK, EDGE also adds the important concept of Link Quality Control
4:00 AM
The Thesis Exhibition, 4 AM, was held between March 19th and April 7th, 2016 in the University Gallery in the School of Art and Design at San Diego State University. The exhibition is the culmination of three years in the graduate studies program in painting and sculpture. Within this report I will discuss the sources of my research and influences, along with the techniques, processes, and choices that go into my practice. It is my feeling that the immediacy and continual nature of modern society is creating greater anxiety, compulsion, and fear within; and I am interested in exploring this in my work. The paintings, sculptures, and installations are an investigation into the anxious and existential nature of the human mind at the present. My intention is for the viewer to experience and have a visceral reaction to the work. I want the light in my work to represent a manic state and the dark to represent a depressive state along with a sense of mystery. Further I want to set up a tension between the viewer and subjects in the paintings; a stage for intimacy and discomfort. I am interested in creating a familiar/comfortable space that is also unsettling and alien for the viewer. The familiar/comfortable elements can be interpreted through the objects in the work referencing the home (couch, rug, mirror), while the surface treatments and manipulations of these elements can give an unknown feeling. I also see the home as a stage/setting representation of the human mind. It is the place where I find comfort and familiarity and yet can also be the place of self-reflection, confusion, and turmoil. I continue to research the anxious and existential nature of the human mind to help visualize, portray, and make tangible the battle within the conscious and subconscious mind. And in a world that focuses on satisfying the more primitive and chaotic nature of the mind, where does the silver lining hide?, San Diego State University
500 year rupture history of the Imperial fault at the international border through analysis of faulted Lake Cahuilla sediments, carbon-14 data, and climate data
We excavated a trench across a sag pond created by a 30 m-wide releasing step along the Imperial fault 1.4 km north of the U.S.-Mexico international border to test earthquake recurrence models. The stratigraphy at the site exhibits distinct pulses of lacustrine and deltaic deposition with localized zones and layers of well-sorted sand deposits interpreted as the result of liquefaction. Evidence for five events is observed in the upper 3.5 m of stratigraphy, which corresponds to deposition from three full lake episodes over the past 400-550 years. Age control is by 14C dating of detrital charcoal from the trenches and correlation to the well-constrained regional chronologic model of Lake Cahuilla. Evidence for events is based on production of accommodation space and associated growth strata, upward fault terminations and fissures, massive liquefaction in the form of sand dike intrusions and sand blow deposits, and significant vertical offset in the step-over area. The two most recent events appear to be significantly larger than the earlier two events based on event-by-event palinspastic reconstruction and correlation to previous trenching studies. Six meters of strike slip passed through the sag in the 1940 Imperial Valley earthquake. The penultimate event produced nearly identical vertical displacement as in the 1940 earthquake, implying that it was also large and likely slipped about 6 m. In contrast, events 3 and 4 produced little vertical displacement from which we infer that displacement in these earthquakes was small at our site. We interpret these as moderate 1979-type earthquakes and that the southern end of these ruptures was likely close to our site. Event 5 is interpreted to be large based on its expression in nearby trenches; our trenches were not deep enough to capture the vertical separation for this event. Together, if each event interpreted as large experienced a similar amount of displacement as in 1940, this implies something on the order of 18 m of displacement in the past 400-550 years, yielding a slip rate of 32-45 mm/yr. This rate is indistinguishable from all geodetically-inferred rates for the Imperial fault and implies that most of the plate motion is accommodated by the Imperial fault at the international border. The CD-ROM, an appendix to the thesis, is available for viewing at the Media Center of the San Diego State University (SDSU) Library., San Diego State University
5G threats and opportunities
The DoD ought to recognize the 5th Generation (5G) deployment as a strategic choice more than a technological one. The infrastructure established will be responsible for both civilian and military telecommunications, as well as public and private data transmission and storage. The infrastructure standards must provide the highest possible security, integrity, and confidentiality while remaining free from interruption of availability. With a universal telecommunications network, the Department of Defense holds a significant role and interest in the development and deployment of the 5G network. Historically as technology advances, a change and increase in the cybersecurity threat landscape must be addressed to ensure fidelity of systems while minimizing negative human impact. China's record of malicious cyber activity, coupled with their public-private partnership in intelligence espionage, presents a geopolitical concern as a global market power for a 5G network. The United States is significantly trailing behind China in the development of a 5G network. The White House and the federal agencies responsible for the U.S. 5G ecosystem are currently working to determine the best course of action. Along with legislation proposals and allocation of funds, the U.S. is attempting to breach the security weakness within cybersecurity as a whole. However, the ongoing trade war between the U.S. and China continues to influence the supply chain for telecommunications equipment. China's leading telecom companies, Huawei and Zhongxing Telecommunications Equipment Corporation (ZTE), are the targets of U.S. intervention strategies. The geopolitical tension resulting from Huawei's involvement by Chinese military and intelligence agencies emphasizes the necessity for the U.S. to develop an independent 5G ecosystem that protects the global telecommunications system from China's control of new technology. The capabilities 5G brings to the DoD are highlighted in this paper. The development of the U.S. 5G network by the private sector, associated security risks, and the challenges that the DoD faces operating on a universal network are also addressed in this paper. Finally, this paper examines the continued interference by the Chinese telecommunications company, Huawei, in U.S. national security and DoD operations through their deployment of 5G technologies and the global reliance on their products and services., San Diego State University
65 years of India's independence
Thesis (M.S.) Computer Science, The focus of this thesis is to create an interactive GIS application to represent progression during '65 years of India's Independence'. This tool will help users to get information about different parts of India's economy like Politics, Agriculture, GDP (Gross Domestic Product), Judiciary and Language Diversity. The information is presented with help of HTML pages, bar charts and maps. The application is developed in JAVA. For maps of India and world, MOJO (Map Objects Java Objects) is used. MOJO is developed by ESRI. Using MOJO, it's easy to represent geographical information on map. The user interface of this application is kept simple and easy to understand for its audience. The attempt has been made to make the keep the application users engaged, with the help of images, symbols, HTML pages and bar charts.
A 7000 year record of paleoearthquakes on the central Garlock fault, near El Paso Peaks, California
A trench excavated across the central Garlock fault, on a small playa near the El Paso Mountains, has revealed a remarkable record of paleoearthquakes. The trench contains event evidence in the form of buried fissures and scarps for six well-resolved earthquakes, designated as events W, U, R, Q, K, and F, within the last 7000 years. The trench and auxiliary exposures that we excavated did not reveal evidence for three poorly-resolved events reported in a previous study and in some cases, we provided alternative interpretations for what was previously observed. Additionally, one paleoearthquake identified in the previous study and thought to be a well-resolved event in the original trench was misinterpreted and is not an event. The multiple exposures allow us a qualitative measure of our interpretation uncertainties, and we believe that our event record is not over-interpreted, although it may be under-interpreted. Radiocarbon dates of detrital charcoal, combined with a technique of interpolating the event ages with sedimentation rates, provide constraints on the timing of faulting events. The most recent earthquake, event W, occurred between A.D. 1450-1640, with a preferred age of A.D. 1530. The penultimate event occurred between A.D. 560-800 and has a preferred age of A.D. 680. Event R has a preferred age of A.D. 325, and occurred between A.D. 225-450. Event Q, which has a preferred age of A.D. 100 and occurred between 40 B.C. - A.D. 240, appears to have more vertical deformation associated with it, indicating it may have been larger event. Event K, which occurred after 3490 B.C. and before 2910 B.C. has a preferred age of 3120 B.C. The oldest identified paleoearthquake, event F, occurred between 5320-4050 B.C., with a preferred age of 4880 B.C. The event ages indicate that earthquake recurrence is highly irregular at the El Paso Peaks site, with individual intervals ranging from as little as 225 years to as much as 3220 years. This suggests that the central Garlock fault follows a Poissonian model of recurrence behavior rather than quasi-periodic behavior. Our analysis shows that, while the irregular recurrence may be an artifact of the geologic evolution of the trench site, there may exist a more fundamental physical process underlying the behavior of the central Garlock fault. This poorly understood process may be related to the temporal and spatial clustering of earthquakes observed for faults in the Eastern California Shear Zone., San Diego State University
A Bayesian hierarchical model for remote sensing analyses with categorical outcomes
Accurate information on the existing distribution of tree species is used as proxy for the health of an ecosystem, as a currency of international environmental treaties, and as a necessary planning tool for forest preservation and rehabilitation, to name just a few of its applications. However, obtaining timely species-level detail across large geographic regions is prohibited by practical challenges and costs to data collection. The extensive coverage and short revisit interval of remote sensing data collected by airborne or satellite instruments could be a critical component of a solution to this problem. In recent years, the public availability of remote sensing data from moderate resolution satellites like the European Space Agency’s Sentinel-2 system has also increased dramatically, making the prospect of utilizing these data more appealing. These remote sensing data sources are measured at a spatial resolution that is inadequate for accurate species-level classification, but ecologists have already begun exploring methods to augment their analyses with the incorporation of moderate-resolution remote sensing data from across different dates or by considering environmental covariates suspected to have relationships with the distributions of species. This thesis introduces a species classification model that facilitates these augmentations and many others. A Bayesian hierarchical model framework enables the separate specification of the observed reflectance process and the species occurrence process. Measurement error and temporal autocorrelation are accounted for in the reflectance sub-model, and its form allows for between-site heterogeneity in measurement dates; a rare freedom in existing research. The species sub-model takes inspiration from ecological joint species distribution models (JSDMs) and estimates the probabilities of all species occurring at each site, preserving between-species relationships inside the model. The specification of the species sub-model also allows covariate effects and the features of the spatial autocorrelation process to vary by species. To demonstrate the elevated process-level understanding facilitated by such a model, it is applied to a dataset consisting of every cloud-free pixel corresponding to 60 known reference sites in a small study area measured by the Sentinel-2 imaging constellation and collected in the calendar year 2020. The dataset was sourced from 132 different daily remote sensing images with an average revisit time of 2.8 days at the site level, qualifying it as the most temporally rich time series analyzed within the existing research focused on tree species classification using remote sensing data. My results confirm the existence of spatial autocorrelation in forest-occupied landscapes, they illustrate how the effect of an abiotic variable on species membership probabilities can vary by species and affect some species but not others, and they reveal that late autumn and winter images hold identifiable spectral profiles when analyzed as a time series. These results feature both novel and familiar visualizations to demonstrate model output for prospective adopters, and as an application of Bayesian modeling, use draws from the posterior distributions of parameters to more clearly communicate the uncertainty associated with a selection of estimates., San Diego State University
A Bridgerian age flora from Del Mar, California
A small but well-preserved transported assemblage of plant fossils collected from the middle Eocene Torrey Sandstone at Del Mar, California, provides, for the first time, an accurate picture of local climate and vegetation 49 to 50 Ma. The flora includes taxa from estuarine, riparian, and coastal lowland habitats of a paratropical broadleaf forest. Living taxa similar to Torrey flora species inhabit warm temperate to paratropical forests of southeastern China, Mexico, and the southeastern United States. The taxonomic composition and foliar physiognomy of Torrey flora fossils indicate a warm (20 C mean annual temperature), equable (less than 8 C mean annual temperature range), frostless climate, with annual rainfall of between 120 and 150 cm, concentrated during the months of April through September. These conclusions suggest that although a climatic drying trend was well established in western North America as early as 50 Ma, conditions remained mesic in the coastal San Diego region. The occurrence of tropical taxa including Tabernaemontana and Eugenia americana in the Torrey flora indicate that the mean annual temperature of the San Diego area had increased between early and middle Eocene time., San Diego State University