Sparse Signal Representation in Digital and Biological Systems

Theories of sparse signal representation, wherein a signal is decomposed as the sum of a small number of constituent elements, play increasing roles in both mathematical signal processing and neuroscience. This happens despite the differences between signal models in the two domains. After reviewing preliminary material on sparse signal models, I use work on compressed sensing for the electron tomography of biological structures as a target for exploring the efficacy of sparse signal reconstruction in a challenging application domain. My research in this area addresses a topic of keen interest to the biological microscopy community, and has resulted in the development of tomographic reconstruction software which is competitive with the state of the art in its field. Moving from the linear signal domain into the nonlinear dynamics of neural encoding, I explain the sparse coding hypothesis in neuroscience and its relationship with olfaction in locusts. I implement a numerical ODE model of the activity of neural populations responsible for sparse odor coding in locusts as part of a project involving offset spiking in the Kenyon cells. I also explain the validation procedures we have devised to help assess the model's similarity to the biology. The thesis concludes with the development of a new, simplified model of locust olfactory network activity, which seeks with some success to explain statistical properties of the sparse coding processes carried out in the network.

MEN WRITING WOMEN: “THE WOMAN QUESTION” AND MALE DISCOURSE OF IRANIAN MODERNITY"

In this dissertation I explore “The Woman Question” in the discourse of Iranian male authors. A pro-modernity group, they placed women’s issues at the heart of their discourse. This dissertation follows the trajectory of the representation of “The Woman Question” as it is reflected in the male discourse over the course of a century. It discusses the production of a literature that was anchored in the idea of reform and concerned itself with issues pertaining to women. These men challenged lifelong patriarchal notions such as veiling, polygamy, gender segregation, and arranged marriages, as well as traditional roles of women and gender relations. This study is defined under the rubrics of “The Woman Question” and “The New Woman,” which I have borrowed from the Victorian and Edwardian debates of similar issues as they provide clearer delineations. Drawing upon debates on sexuality, and gender, this dissertation illustrates the way these men championed women was both progressive and regressive. This study argues that the desire for women’s liberation was couched in male ideology of gender relations. It further illustrates that the advancement of “The Woman Question,” due to its continuous and yet gradual shifting concurrent with each author’s nuanced perception of women’s issues, went through discernible stages that I refer to as observation, causation, remedy, and confusion. The analytical framework for this project is anchored in the “why” and the “how” of the Iranian male authors’ writings on women in addition to “what” was written. This dissertation examines four narrative texts—two in prose and two in poetry—entitled: “Lankaran’s Vizier,” “The Black Shroud,” “‘Arefnameh,” and “Fetneh” written respectively by Akhundzadeh, ‘Eshqi, Iraj Mirza, and Dashti. Chapter one outlines the historical background, methodology, theoretical framework, and literature review. The following chapters examine, the advocacy for companionate marriage and romantic love, women and nationalistic cause, veiling and unveiling, and the emerging figure of the New Iranian Woman as morally depraved.

UTILIZING ELECTRONIC NOSE AND GC-MS TO EXAMINE CRITICAL FACTORS INFLUENCING THE FORMATION OF ODOROUS VOC’S IN BIOSOLIDS.

Despite the efforts to better manage biosolids field application programs, biosolids managers still lack of efficient and reliable tools to apply large quantities of material while avoiding odor complaints. Objectives of this research were to determine the capabilities of an electronic nose in supporting process monitoring of biosolids production and, to compare odor characteristics of biosolids produced through thermal-hydrolysis anaerobic digestion (TH-AD) to those of alkaline stabilization in the plant, under storage and in the field. A method to quantify key odorants was developed and full scale sampling and laboratory simulations were performed. The portable electronic nose (PEN3) was tested for its capabilities of distinguishing alkali dosages in the biosolids production process. Frequency of recognition of unknown samples was tested achieving highest accuracy of 81.1%. This work exposed the need for a different and more sensitive electronic nose to assure its applicability at full scale for this process. GC-MS results were consistent with those reported in literature and helped to elucidate the behavior of the pattern recognition of the PEN3. Odor characterization of TH-AD and alkaline stabilized biosolids was achieved using olfactometry measurements and GC-MS. Dilution-to-threshold of TH-AD biosolids increased under storage conditions but no correlation was found with the target compounds. The presence of furan and three methylated homologues in TH-AD biosolids was reported for the first time proposing that these compounds are produced during thermal hydrolysis process however, additional research is needed to fully describe the formation of these compounds and the increase in odors. Alkaline stabilized biosolids reported similar odor concentration but did not increase and the ‘fishy’ odor from trimethylamine emissions resulted in more offensive and unpleasant odors when compared to TH-AD. Alkaline stabilized biosolids showed a spike in sulfur and trimethylamine after 3 days of field application when the alkali addition was not sufficient to meet regulatory standards. Concentrations of target compounds from field application of TH-AD biosolids gradually decreased to below the odor threshold after 3 days. This work increased the scientific understanding on odor characteristics and behavior of two types of biosolids and on the application of electronic noses to the environmental engineering field.