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Title: DEVELOPMENT OF A TESTBED FOR STUDYING SECURITY ISSUES IN VOIP NETWORKS
Creator: Olawoye, Oladeji
Date: 2011-12-06, 2011-12
Description: VoIP is increasingly becoming an alternative to the traditional PSTN for Telephony this is as a result of certain advantages and services...
Show moreVoIP is increasingly becoming an alternative to the traditional PSTN for Telephony this is as a result of certain advantages and services offered by VoIP. VoIP will be considered able to fully replace PSTN if it can provide same or better Quality of Service and Security guaranty as PSTN. Delivering telephony services over (best-effort and connectionless) IP data network faces two main issues not experienced in PSTN, security and quality of service; security in the sense that telephone calls will be susceptible to attacks that are known in the Internet, quality of service in the sense that voice packets now have to compete with packets of other traffic for a limited bandwidth. Researches are ongoing in these two fields to make experience on VoIP similar to the traditional telephone. The focus of this thesis work is in the security aspect. SIP protocol has become one of the most popular signaling protocols used for VoIP, SIP architecture is an open architecture originally developed for trusted communications among trusted partners, and therefore much thought was not given to security. Adopting SIP as a main protocol used in VoIP in the Internet where there are where there are lots of hostile users calls for more ways to properly secure its use. The thesis work involves setting up of a SIP based VoIP network based on open source SIP telephony platforms to study various security issues in a SIP-Based VoIP network and experiment some proposed detection mechanism. The contribution of this work is to develop a graphical user interface in the UNIX environment using Java that makes the execution of the attack scenarios easy to carry out and observe.
M.S. in Electrical Engineering, December 2011
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Title: THERMAL AND FLUID FLOW FEASIBILITY STUDY OF A CIRCULAR COUETTE FLOW REACTOR VIA PLANAR LASER-INDUCED FLUORESCENCE IMAGING
Creator: Bittner, Peter R.
Date: 2012-04-28, 2012-05
Description: Liquid fueled microcombustors face many challenges in their development, the most prominent being high temperature gradients and radiative...
Show moreLiquid fueled microcombustors face many challenges in their development, the most prominent being high temperature gradients and radiative effects. Because the walls of microcombustors are thin, they offer very little resistance to conductive heat transfer, regardless of the materials used. This can cause very high heat losses that lead to large temperature gradients in the gas compared to nearly uniform temperatures inside conventional combustion chambers. In this investigation a circular Couette flow reactor (CCFR) and planar laser induced fluorescence (PLIF) are used to examine the feasibility of studying vapor distributions of a monodisperse acetone droplet stream, formed by a vibrating orifice aerosol generator (VOAG), exposed to combinations of varying velocity gradients, temperature gradients and radiant heating. The acetone droplets are injected through various ports on the CCFR to vary the time for vaporization of the droplets inside the reactor. Initial results of the operating CCFR uses acetone droplets seeded into the test section to demonstrate the fluorescence of the liquid and vapor acetone within the test section.
M.S. in Mechanical, Materials, and Aerospace Engineering, May 2012
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Title: SOFT ERROR TOLERANT LATCH CIRCUIT DESIGN FOR DEEPLY SCALED CMOS TECHNOLOGY
Creator: Nan, Haiqing
Date: 2012-01-25, 2012-05
Description: As CMOS technology keeps scaling down, circuit designers face variety of challenges. Due to the scaling of supply voltage and node capacitance...
Show moreAs CMOS technology keeps scaling down, circuit designers face variety of challenges. Due to the scaling of supply voltage and node capacitance, digital circuits are more aware of noise and variations, which cause reliability issues such as soft error. Traditionally the soft error aware VLSI design is limited to applications which require high reliability and operated in high radiation environment such as avionics applications, medical equipments, space industry and military applications. However, with CMOS technology scales down to nanometer region, the VLSI circuits can also be affected by soft errors at ground level which features low radiation energy. In this thesis, totally 5 soft error tolerant latch designs are proposed including HLR-1, HLR-2, HLR-CG1, HLR-CG2, and HLR-CG3. All the proposed designs protect internal nodes as well as output node for soft error regardless the radiation energy. The proposed HLR-1 and HLR-2 latch circuits tolerate soft error for non-CG systems. Since the proposed HLR-1 and HLR-2 designs take advantages of floating node to tolerate soft error, these two designs cannot be applied with clock gating techniques and the minimum clock frequency of these two designs should be greater than 16MHz in order to maintain correct logic at the floating node. The power consumption and circuit delay between the proposed HLR-1 and HLR-2 designs are very close. The proposed HLR-1 design achieves a small amount of benefits in terms of power and delay compared with the proposed HLR-2 design. But the proposed HLR-2 circuit reduces area 3.5% compared to the proposed HLR-1 circuit. The proposed HLR-CG1, HLR-CG2 and HLR-CG3 latch designs fully tolerate soft error regardless of radiation energy for both CG and non-CG systems. Due to the auto correction mechanism embedded in the proposed HLR-CG1, HLR-CG2 and HLRCG3 designs, any soft error at any location will be automatically corrected without generating any floating nodes. The proposed HLR-CG3 features the smallest power consumption and delay but it has the largest area overhead compared to HLR-CG1 and HLR-CG2 circuits. The proposed HLR-CG1 design features the smallest area compared with HLRCG2 and HLR-CG3 designs. The design cost of HLR-CG2 design is between the proposed HLR-CG1 and HLR-CG3 designs. All the proposed designs achieve faster speed and smaller PDP compared to previous hardening techniques. Compared to the proposed HLR-1 design, previous designs increases power 3.77% on average, delay 272.74% on average, PDP 300.29% on average and decreases area 7.09% on average. Compared to the proposed HLR-2 design, previous designs increases power 3.77% on average, delay 272.40% on average, PDP 299.89% on average and decreases area 3.93% on average. Compared to the proposed HLR-CG1 design, previous designs increases area 19.65% on average, delay 213.14% on average, PDP 203.78% on average and decreases power 5.82% on average. Compared to the proposed HLR-CG2 design, previous designs increase area 6.49% on average, delay 193.28% on average, PDP 223.45% on average and power 6.51% on average. Compared to the proposed HLR-CG3 design, previous designs increases delay 272.18% on average, PDP 314.38% on average, power 8.01% on average and area 2.93% on average.
Ph.D. in Electrical and Computer Engineering, May 2012
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Title: COMPARISON OF THE EFFICACY OF THREE SANITIZERS WITH 20,000 PPM CALCIUM HYPOCHLORITE FOR INACTIVATION OF SALMONELLA ON ARTIFICIALLY CONTAMINATED ALFALFA SEEDS
Creator: Li, Qing
Date: 2015, 2015-12
Description: This study evaluated the efficacy of three alternative sanitizers, acidified sodium chlorite (ASC, also known as Sanova), stabilized oxychloro...
Show moreThis study evaluated the efficacy of three alternative sanitizers, acidified sodium chlorite (ASC, also known as Sanova), stabilized oxychloro-based sanitizer (SOC, also known as Germin-8-or), and Tsunami 100 in comparison with 20,000 ppm Ca(OCl)2 for treatment of alfalfa seeds artificially inoculated with Salmonella. Small-scale experiments were conducted to determine the best treatment conditions for each sanitizer and how the initial Salmonella contamination level on seeds or Salmonella type may have on the efficacy of the sanitizers. Large-scale studies were performed to evaluate the commercial applicability of these sanitizers. As a comparison, seeds were also treated with 20,000 ppm Ca(OCl)2 for 15 min. To determine the optimal treatment condition, ten g of seeds containing 103 CFU/g (seed lot 1) or 105 CFU/g (seed lot 2) of S. Typhimurium expressing green fluorescent protein was treated with different concentrations of ASC, SOC, and Tsunami 100 for different period of treatment time. Results showed that the efficacy of ASC and SOC increased with increasing concentrations (up to 1500 ppm) and treatment time (up to 3 h); however, the germination rates for seeds treated with > 1200 ppm of either sanitizer was < 80%. When seeds from lot 1 were treated with 800 ppm of ASC or SOC for 3 h, the level of Salmonella reduced, respectively, by 2.6 log units or >2.5 log units to an undetectable level, compared with the 1.1 log unit decrease observed in seeds treated with Ca(OCl)2. When seeds from seed lot 2 (5 log units) were treated with 800 ppm of ASC or SOC for 3 h, the level of Salmonella were reduced by 3.8 log units or >4.3 log units to an undetectable level, respectively, compared with the 2 log units decrease observed in seeds treated with Ca(OCl)2. Treatment with 80 ppm of Tsunami 100 from 10 min to 24 h kept the germination rate higher than 85% but only reduced the Salmonella count by 0 to 1.8 log units. Between two seed lots, results of ASC showed that sanitizer could reduce more pathogen when the seeds contained higher initial Salmonella level. Ten g of seeds containing 105 CFU/g of four-strain cocktail of Salmonella was treated with ASC and SOC by optimal treatment condition. SOC and ASC eliminated Salmonella number by 2.8 and 1.6 log units respectively, less effective compare with the treatment of seed lot 1. For large-scale runs, 1 kg of seeds spiked with 1 % (w/w) of inoculated seeds containing 105 CFU/g of S. Typhimurium was treated with SOC and ASC under optimal treatment conditions. Salmonella level in seeds treated with 800 ppm SOC or ASC for 3 h decreased by 3.9 or 3.6 log units, compared with a 3.3 log reduction in seeds treated with 20,000 ppm Ca(OCl)2. The stabilized oxychloro-based sanitizer may provide an alternative seed treatment method for sprout growers.
M.S. in Food Safety and Technology, December 2015
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Title: LIPID-LIPID AND LIPID-DRUG INTERACTIONS IN BIOLOGICAL MEMBRANES
Creator: Martynowycz, Michael W.
Date: 2016, 2016-07
Description: Interactions between lipids and drug molecules in biological membranes help govern proper biological function in organisms. The mechanisms...
Show moreInteractions between lipids and drug molecules in biological membranes help govern proper biological function in organisms. The mechanisms responsible for hydrophobic drug permeation remain elusive. Many small molecule drugs are hydrophobic. These drugs inhibit proteins in the cellular interior. The rise of antibiotic resistance in bacteria is thought to be caused by mutations in protein structure, changing drug kinetics to favor growth. However, small molecule drugs have been shown to have different mechanisms depending in the structure of the lipid membrane of the target cell. Biological membranes are investigated using Langmuir monolayers at the airliquid interface. These offer the highest level of control in the mimetic system and allow them to be investigated using complementary techniques. Langmuir isotherms and insertion assays are used to determine the area occupied by each lipid in the membrane and the change in area caused by the introduction of a drug molecule, respectively. Specular X-ray re ectivity is used to determine the electron density of the monolayer, and grazing incidence X-ray diffraction is used to determine the inplane order of the monolayer. These methods determine the affinity of the drug and the mechanism of action. Studies are presented on hydrophobic drugs with mammalian membrane mimics using warfarin along with modified analogues, called superwarfarins. Data shows that toxicity of these modified drugs are modulated by the membrane cholesterol content in cells; explaining several previously unexplained effects of the drugs. Membrane mimics of bacteria are investigated along with their interactions with a hydrophobic antibiotic, novobiocin. Data suggests that permeation of the drug is mediated by modifications to the membrane lipids, and completely ceases translocation under certain circumstances.
Ph.D. in Physics, July 2016
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Title: RATING GOALS IN PERFORMANCE APPRAISAL: DEVELOPMENT OF AN INITIAL TAXONOMY AND MEASURE
Creator: Overfors, Christine M.
Date: 2012-12-04, 2012-12
Description: Rating employee performance is a common task undertaken by managers across most organizations with significant outcomes and complex...
Show moreRating employee performance is a common task undertaken by managers across most organizations with significant outcomes and complex antecedents. Efforts to understand the processes behind performance ratings have been the focus of substantial research within the performance appraisal domain. This study examined the structure of conscious rating goals pursued by managers when assigning ratings to employees by investigating an initial taxonomy of these goals based on both theoretical literature and managerial interviews. Additionally, a scale was developed as a means to effectively measure these goals to better address future research questions. The results from this preliminary work suggest four distinct rating goals endorsed by managers: Positive Development, Conflict Avoidance, Weaknesses and Consequences, and Equitable Treatment. Implications and avenues for future research are discussed.
M.S. in Psychology, December 2012
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Title: GRAPH PARTITIONING WITH EIGENVECTORS
Creator: Panek, James
Date: 2017, 2017-05
Description: The Cheeger constant of a graph quantities how well a graph can be cut yield- ing two (typically) large vertex sets by a small edge cut. Lower...
Show moreThe Cheeger constant of a graph quantities how well a graph can be cut yield- ing two (typically) large vertex sets by a small edge cut. Lower and upper bounds have been developed using the eigenvalues and eigenvectors of the normalized Laplacian matrix of the graph. Here a classic sweep algorithm is studied using linear combinations of eigenvectors, specifically the columns of approximate discrete Green's functions. It is then shown, statistically on certain families of random graphs following a stochastic block model, that it is enough to use two eigenvalues and vectors to improve this classic algorithm's upper bound in most cases.
M.S. in Applied Mathematics, May 2017
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Title: THE FATE OF TOTAL ARSENIC CONTENT IN RICE FOR SEVERAL PROCESSING VARIABLES: RINSING AND HIGH VOLUME COOK WATER
Creator: Parvanehvar, Alireza
Date: 2015, 2015-07
Description: This project evaluated rinsing and cooking rice in a high volume of water for several brown and white rice’s, from the United States, India...
Show moreThis project evaluated rinsing and cooking rice in a high volume of water for several brown and white rice’s, from the United States, India and Iran. There has been more attention to the arsenic content in certain foods, such as apple juice, and regional rice in the U.S. has become an issue as well. The purpose of rinsing or using a high volume of water to cook rice was to reduce the total arsenic content. Previous work on long grain white rice showed a 25% to 46% reduction of arsenic in rice cooked in a high volume of water. This previous work showed no significant decrease in arsenic in rice rinsed in 2 parts of water to rice. This project optimized the procedure of rinsing and cooking rice in a high volume of water from previously presented work. Advances in sampling due to more efficient procedures in sample preparation with emphasis on chilling, grinding and drying prepared rice significantly reduced the relative standard deviation from >10% to 3-7%RSD. Arsenic was measured for total and species (As+3, As+5, monomethyl arsenite, dimethyl arsenate) and the two methods compared within 90% when analyzed by ICP-MS (total) and HPLC-ICP-MS (Species).Results from this project demonstrated an average 45.91% decrease in total arsenic for rice cooked in a high volume of water (1 part of rice to 7 parts of water) and a 50.28% in average decrease in inorganic arsenic for rice cooked using the same procedure. This data provides information on arsenic content in domestic and international rice and provides processing strategies to reduce the arsenic content.
M.S. in Food Process Engineering, July 2015
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Title: Architectural Considerations for Lunar Long Duration Habitat
Creator: Bahrami, Payam
Date: 2011-07, 2011-07
Description: The future of space exploration science and technology is expected to move toward long duration missions. During this long duration missions...
Show moreThe future of space exploration science and technology is expected to move toward long duration missions. During this long duration missions the most important factor to success will be the habitation system, the place that crew will live and work. The broad range of future space exploration, new advances in technology and increasing demand for space travel and space tourism will create great opportunities for architects to use their special abilities and skills in the realm of space. The lunar habitat is defined as a multidisciplinary task and cannot be considered an independent project from the main module. Therefore, habitability will become the most important aspect of future human exploration. A successful design strategy should integrate architecture, structure and other disciplines and should bring in elements such as psychological and physiological factors, human interfaces, and privacy. The current research provides “Habitat Architectural Design System (HADS)” in order to evaluate lunar habitat concepts based on habitability, functional optimization, and human factors. HADS helps to promote parametric studied and evaluation of habitat concepts. It will provide a guideline dependent upon mission objectives to standardize architectural needs within the engineering applications and scientific demands. The significance of this research is the process of developing lunar habitat concepts using an architectural system to evaluate the quality of each concept via habitability aspects. This process can be employed during the early stage of design development and is flexible enough to be adjusted by different parameters according to the objectives of lunar mission, limitations, and cost. It also emphasizes the importance of architecture involvement in space projects, especially habitats.
Ph.D. in Architecture, July 2011
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Title: VISUAL TRAINING AT ILLINOIS INSTITUTE OF TECHNOLOGY: AESTHETICS IN ARCHITECTURAL EDUCATION
Creator: Jones, Kristin
Date: 2016, 2016-05
Description: Over the course of 78 years, an aesthetic ideal which embodies architectural values has been collectively cultivated through Visual Training...
Show moreOver the course of 78 years, an aesthetic ideal which embodies architectural values has been collectively cultivated through Visual Training at the Illinois Institute of Technology (IIT) school of architecture in Chicago. This dissertation provides a comprehensive explanation of Visual Training as it has been conducted at IIT. It promotes a better understanding of the background of Visual Training, the pedagogical practice of the Visual Training exercises, and the ongoing value of the course. The dissertation traces the underpinnings of Visual Training through the writings of Walter Peterhans, founder and Professor of Visual Training at IIT from 1938-1960, Ludwig Mies van der Rohe, Professor and Director of Architecture at IIT from 1938-1958 and other key figures. The thesis shows how the Visual Training program at IIT was influenced by movements in philosophy and mathematics in early 20th century Germany and how existing pedagogy at the Bauhaus was adapted to serve its aim. The dissertation includes an explanation of each exercise in the Visual Training program. It makes explicit the point of each exercise, how each one is conducted and why. Original detailed descriptions, illustrated with examples, show what a student gains from each exercise and how the process of performing the exercise achieves that end. The dissertation compares the way in which the Visual Training program originally developed in relation to other courses in the architecture curriculum to disclose the meaning of architecture, and what has happened in Visual Training as the architecture program at IIT has continued to evolve. The thesis brings to light enduring epistemological tensions underlying architectural education.
Ph.D. in Architecture, May 2016
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Title: STRAWBERRY EXTRACT ATTENUATES ELEVATED FREE FATTY ACID AND/OR GLUCOSE MEDIATED IMPAIRED INSULIN SIGNALING IN VITRO IN HUMAN SKELETAL MUSCLE CELLS
Creator: Kangath, Archana
Date: 2013, 2013-07
Description: Elevated glucose and free fatty acids (FFA) are evident in individuals with insulin resistance (IR) and are associated with oxidative stress....
Show moreElevated glucose and free fatty acids (FFA) are evident in individuals with insulin resistance (IR) and are associated with oxidative stress. Anthocyanins are suggested to have favorable effects on human health due to their ability to modulate oxidative stress and cell signaling pathways in peripheral tissues. We hypothesized that strawberry anthocyanins (Str) will improve oxidative stress-mediated impaired insulin signaling in vitro in human skeletal muscle cells (HSMCs). Oxidative stress was generated using physiologically high glucose, FFA or a combination of both for 2–6 h with and without Str (0.1–1.0 mg/mL) in vitro in HSMCs. Cell viability was not affected by any of the above treatments/time. At the end of treatments, cells were treated with insulin (100 nM) for 20 min. Phosphorylation of Akt (p-Akt/Akt) was studied using AlphaScreen® Surefire® assay as a measure of insulin signaling. Our results indicate that FFA (2 mM) or combination of Glucose (15 mM) + FFA (2 mM) significantly decreased p-Akt/Akt compared to control cells treated with phosphate buffered saline (P<0.05). ST extract restored FFA and Glucose + FFA-induced reductions in p-Akt/Akt levels (P<0.05). These in vitro data suggest a role of strawberry in improving insulin sensitivity having potentially important implications for people with IR.
M.S. in Biological Sciences, July 2013
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Title: TOWARDS REDUCING BUILDING ENERGY CONSUMPTION: COMPARISON OF THE RESIDENTIAL PLANNING PATTERNS IN BEIJING, SHANGHAI AND GUANGZHOU
Creator: Wang, Nan
Date: 2013, 2013-07
Description: The objective of this research is to investigate the influence of urban planning patterns on building energy consumption in different climate...
Show moreThe objective of this research is to investigate the influence of urban planning patterns on building energy consumption in different climate zones. Urban planning patterns affect the thermal performance and energy efficiency of buildings. This research focuses on the planning aspects, explores the energy consumption of a group of buildings with different planning pattern by utilizing single building as a baseline, and identifies planning patterns that can help to reduce the total heating and cooling energy consumption of the buildings. The investigations are carried out in the three largest cities in China – Beijing, Shanghai, and Guangzhou, which represent different climate zones. The results of these three cities are compared to find out the influence of local climate on building energy consumption. Different planning patterns are investigated in this research through changing building parameters: aspect ratio, orientation and layout. It is found that these parameters have important influence on reducing building’s energy consumption. It is also found that in different climate conditions, the influence of planning patterns on building’s energy consumption is different, which suggests that the selection of planning pattern will be different for each location. This research makes a significant contribution to the reduction of building energy consumption from urban planning perspective. In addition, two case studies of carefully selected residential communities with fixed site and fixed density are evaluated, and some suggestions for improvement are proposed as a result of the study. Such suggestions can help to propose a prototype model guiding the future architectural and urban planning work.
PH.D in Architecture, July 2013
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Title: FATIGUE AND BARKHAUSEN EFFECT
Creator: Tong, Wei
Date: 2013, 2013-05
Description: Piezomagnetism designates a change in the magnetization of materials induced by mechanical actions such as tension or compression. The type of...
Show morePiezomagnetism designates a change in the magnetization of materials induced by mechanical actions such as tension or compression. The type of Barkhausen effect that occurs in this work consists of sudden, discontinuous jumps in a material’s magnetization that appear in response to smooth (continuous) stress variations. A series of strain controlled fatigue tests with an alternating sinusoidal waveform were carried out to study the relationship between the endurance limit and the Barkhausen effect. Results of fatigue tests on steel specimens exhibiting Barkhausen pulses at various stages are reported and a threshold-crossing analysis is applied to the test results. These studies show that when the fatigue limit is approached, the Barkhausen pulses become, in general, more intense in amplitude and quantity than at other stress levels. A hypothetical mechanism is proposed that relates the intensity of the Barkhausen response to the inception of micro-cracking and rearrangements of the mechanical lattice at the microscopic level.
PH.D in Civil Engineering, May 2013
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Title: ANALYZING REPRODUCING KERNEL APPROXIMATION METHODS VIA A GREEN FUNCTION APPROACH
Creator: Ye, Qi
Date: 2012-04-22, 2012-05
Description: In this thesis, we use Green functions (kernels) to set up reproducing kernels such that their related reproducing kernel Hilbert spaces ...
Show moreIn this thesis, we use Green functions (kernels) to set up reproducing kernels such that their related reproducing kernel Hilbert spaces (native spaces) are isometrically embedded into or even are isometrically equivalent to generalized Sobolev spaces. These generalized Sobolev spaces are set up with the help of a vector distributional operator P consisting of finitely or countably many elements, and possibly a vector boundary operator B. The above Green functions can be computed by the distributional operator L := P TP with possible boundary conditions given by B. In order to support this claim we ensure that the distributional adjoint operator P of P is well-defined in the distributional sense. The types of distributional operators we consider include not only di erential operators but also more general distributional operators such as pseudo-di erential operators. The generalized Sobolev spaces can cover even classical Sobolev spaces and Beppo-Levi spaces. The well-known examples covered by our theories include thin-plate splines, Mat´ern functions, Gaussian kernels, min kernels and others. As an application for high-dimensional approximations, we can use the Green functions to construct a multivariate minimum-norm interpolant s f;X to interpolate the data values sampled from an unknown generalized Sobolev function f at data sites X Rd. Moreover, we also use Green functions to set up reproducing kernel Banach spaces, which can be equivalent to classical Sobolev spaces. This is a new tool for support vector machines. Finally, we show that stochastic Gaussian fields can be well-defined on the generalized Sobolev spaces. According to these Gaussian-field constructions, we find that kernel-based collocation methods can be used to approximate the numerical solutions of high-dimensional stochastic partial differential equations.
Ph.D. in Applied Mathematics
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Title: LONGITUDINAL MEASUREMENT EQUIVALENCE IN TRAINING EVALUATION: TESTING FOR ALPHA, BETA, AND GAMMA CHANGE IN SELF-EFFICACY
Creator: Wright, Sean Christopher
Date: 2013, 2013-12
Description: When evaluating a training program, it is common to make longitudinal comparisons between pre-training and post-training measures of one or...
Show moreWhen evaluating a training program, it is common to make longitudinal comparisons between pre-training and post-training measures of one or more learning outcomes. This study was conducted to demonstrate the need to investigate the type of change observed in a self-efficacy measure collected pre- and post-training using a military sample. Using a variation of CFA methods developed by Schmitt (1982), tests were conducted to determine whether pre-post differences in the measure were due to a true (i.e., alpha) change in the construct, or if trainees had recalibrated (i.e., beta change) or reconceptualized (i.e., gamma change) their use of the self-efficacy measures over time. In addition, the potential relationship between task difficulty and the type of observed change was investigated. Analyses found that gamma change did occur with regard to the covariance between the latent factors of self-efficacy, and partial beta change occurred with regard to the latent factor variance. Task difficulty subgroup analyses reflected a very similar result to the primary analysis suggesting that task difficulty has little or no effect on the type of change observed. Implications for training evaluation research are discussed, as well as study limitations and future research directions.
M.S. in Psychology, December 2013
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Title: INFLUENCE OF THE FREQUENCY OF LOADING ON THE PIEZO-BARKHAUSEN RESPONSE OF STEEL FOR FATIGUE LIFE ASSESSMENT
Creator: Coulibaly, Jibril
Date: 2014, 2014-07
Description: Steel can fail prematurely under repeated cyclic loading below its proportional limit (or yielding point). Provided that a certain threshold...
Show moreSteel can fail prematurely under repeated cyclic loading below its proportional limit (or yielding point). Provided that a certain threshold in the loading magnitude, known as the endurance limit, is not exceeded, the material can sustain an infinite number of cycles (N 107). Recent interests in the piezo-magnetic behavior of ferromagnetic steels have been successfully providing reliable and physical indicators of fatigue properties of the material. Cyclic mechanical strain applied to ferromagnetic steels produce abrupt variations in the magnetization of the material referred to as piezo-Barkhausen pulses. Among the many variables influencing fatigue characteristics, the influence of the frequency of loading upon the piezo-Barkhausen response of steel is investigated herein. While the amplitude of the pulses varies, the cumulative piezo-Barkhausen indicator of damage is independent of the frequency and provides a specific measure of damage for a given level of applied strain and may be a way to evaluate service life. The distribution of the dominant frequency of the observed pulses also permits one to separate the stable states of loading from those leading to fatigue failure. Further observations on the piezo-Barkhausen signals particularities have also been made to provide a greater insight on the micro mechanisms of fatigue and damage accumulation in steel.
M.S. in Civil Engineering, July 2014
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Title: DISJUNCTNESS PROPERTIES RESULTING FROM CONCATENATION OF GROUP TESTING MATRICES
Creator: Clardy, Melinda Bulin
Date: 2015, 2015-05
Description: This thesis discusses matrix properties as they relate to the idea of non-adaptive group testing. This is accomplished by first considering...
Show moreThis thesis discusses matrix properties as they relate to the idea of non-adaptive group testing. This is accomplished by first considering the history of group testing and then exploring existing results. The next chapter of this thesis discusses taking a given binary matrix and using this as an inner code with some symbol matrix as an outer code to create a new binary matrix. The process is called a concatenation construction and we will cover a few types including the orthogonal array construction, a 𝜆-separating hash family construction, code concatenation, and DNA Sudoku. We conclude by elaborating on primary results coming from orthogonal array construction and 𝜆-separating hash family constructions. These give results pertaining specifically to Steiner systems and cover-free families.
M.S. in Applied Mathematics, May 2015
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Title: IMPACT OF THERMAL PROCESSING ON THE STRUCTURAL AND IMMUNOLOGICAL PROPERTIES OF MAJOR EGG AND MILK ALLERGENS
Creator: Chandra, Srinivasa Rao
Date: 2011-05-03, 2011-05
Description: The underlying mechanism of food allergy is not well understood. Research has increasingly focused on the characterization of food allergens....
Show moreThe underlying mechanism of food allergy is not well understood. Research has increasingly focused on the characterization of food allergens. Since most foods are cooked prior to consumption, information relating to the impact of thermal processing on the properties of allergenic proteins is critical for allergen risk assessment. This study examined the impact of thermal processing on the structure and the antigenic potential of the major egg and milk allergens, ovomucoid (OVO) and -lactoglobulin (BLG) both A and B variants respectively. OVO and BLG were subjected to thermal processing under moist and dry heat conditions for 10 min. No significant changes in the solubility of both proteins were observed after boiling, autoclaving or dry heating up to 204C. At 232C, a significant protein loss was observed. Inhibition ELISA was used to determine the effect of heat treatment on the capacity of these proteins to bind rabbit derived IgG antibodies. While boiling and autoclaving caused a decrease in IgG binding of OVO, an increase in IgG binding of BLG was observed under the same experimental conditions. A similar pattern that a decrease in antigen binding potentials by OVO and an increase in antigen binding potentials by BLG A and B variants was noticed during dry heat treatment at temperatures 232C and above. Structural analyses were performed using circular dichroism spectroscopy (CD) and differential scanning calorimetry (DSC). Both proteins showed variations in the secondary structure when subjected to heating in water and PBS. In the presence of water, variable temperature scan with CD resulted in transition temperatures of OVO and BLG variants in the range of 70-75oC and 80-85oC respectively. There is no significant change in the secondary structure of BLG variants prepared in PBS. DSC study showed the transition temperatures of 84oC, 129oC for OVO and at 80oC, 195oC for BLG (A & B) variants under moist and dry heat conditions respectively. Overall, both proteins were highly resistant to thermal denaturation and retained their antigenic potential at typical cooking temperatures.
M.S. in Food Safety and Technology, May 2011
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Title: FACTORS AFFECTING THE SANITIZER EFFICACY IN PREVENTING SALMONELLA TRANSFER DURING POSTHARVESTWASHING OF CUT LETTUCE
Creator: Zang, Mingxia
Date: 2014, 2014-07
Description: This study investigated the spread of Salmonella during postharvest washing of contaminated lettuce and determined the factors that affect the...
Show moreThis study investigated the spread of Salmonella during postharvest washing of contaminated lettuce and determined the factors that affect the efficacy of chlorine in preventing Salmonella cross-contamination. A bench-scale washing system was assembled. It consisted of a 15 gal tank equipped with a submersible pump and various probes to measure wash water properties including pl-l, temperature, chlorine level. oxidation reduction potential (ORP), turbidity, and total organic carbon (TOC) level. Eight grams of cut romaine lettuce inoculated with approximately 7 log CFU/g of Salmonella typhimurium expressing green fluorescent protein were added to 40 L of sterile tap water or spent wash water collected from a commercial produce processing facility together with 800 g of uninoculated lettuce and washed for 2 min. Washing trials were performed at 3°C under different levels of chlorine treatment (0. 5, 10, 20 and 30 ppm of sodium hypochlorite). Small-scale (100 mL) experiments were performed to determine the effects of organic matter (lettuce homogenate) and solids (play sand) on the efficacy of chlorine in wash water. Without chlorine treatment, the spread of Salmonella occurred during lettuce washing in both sterile tap water and in spent industry water. With 5 ppm ofchlorine. although no Salmonella was detected in the wash water, the pathogen was found in the uninoculated lettuce after culture enrichments. When the chlorine level increased to either 10 or 20 ppm of chlorine, no Salmonella was detected in the wash water or the uninoculated lettuce. Similar experiments were performed using the spent industry water. Salmonella transfer occurred at chlorine of 10 or 20 ppm. Transfer was prevented when the chlorine level was raised to 30 ppm. IX Data from the small-scale experiments indicated that the increase in organic contents resulted in a lower level of free chlorine and a greater survival of Salmonella. At 5 ppm of chlorine, the level of Salmonella increased from not detectable « 1 log CFU/ml) to completely unaffected (4.3 ± 0.4 log CFU/ml) when the TOC level increased from 10.6 ± 10.4 to 164.0 ± 21.2 mg/L. Also, the increase in solid contents led to a greater survival of Salmonella even though the free chlorine level remained unchanged. At 0.5 ppm of chlorine, the level ofSalmonella increased from not detectable « 1 log CFU/ml) to completely unaffected (4.2 ± 0.1 log CFU/ml) when the turbidity level increased from 0.7 ± 0.5 to 378.2 ± 53.5 NTU. In summary, the use of sufficient chlorine could prevent Salmonella cross-contamination but the effective chlorine level was affected by the organic load and solid content present in the wash water. Since the chlorine efficacy was the key to preventing cross-contamination and organic load was an important factor affecting the chlorine efficacy, measurements of the organic load was needed to determine the level ofchlorination needed in the wash water. However, current methods for measuring TOC took a few hours to perform. Turbidity measurements which could be done in a minute had been frequently used in the produce industry to determ ine wash water quality. In this study. it was found that a linear correlation could be established between turbidity and TOC suggesting that turbidity could be a good predictor of the organic load in produce wash water.
M.S. in Food Safety and Technology, July 2014
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Title: IN VITRO ASSAYS FOR ASSESSING THE IMPACT OF PROCESSING ON THE ALLERGENIC POTENTIAL OF MILK ALLERGENS
Creator: Zhao, Yuhui
Date: 2014, 2014-07
Description: A better understanding of how processing may affect the allergenicity of proteins will allow a more accurate allergen risk assessment and...
Show moreA better understanding of how processing may affect the allergenicity of proteins will allow a more accurate allergen risk assessment and achieve a greater success in food allergy management. To determine whether food processing can affect the allergenic potential of proteins, immunochemical methods are commonly used, however, these methods are not able to determine changes in the proteins’ ability to elicit allergic reactions. Although food challenge studies are the gold standard for determining the allergenicity of proteins, such studies are seldom performed due to ethical reasons and the difficulty in recruiting a sufficient number of study participants. In recent years, a number of mediator release assays have been developed to measure the allergenic potential of food proteins in vitro. How these cell-based assays can be used to assess the impact of thermal or other processing conditions on the allergenic potential of proteins remains to be determined. This study evaluated the use of sensitized rat basophilic leukemia (RBL) cells for assessing the impact of boiling on the allergenic potential of milk allergens by measuring changes in the proteins’ ability to induce cell degranulation and the release of β-hexosaminidase. RBL-2H3 cells sensitized with rat IgEs that were specifically raised against NIST non-fat milk standard reference material, β-lactoglobulin (BLG), α-lactalbumin (ALA) and α-casein (αCAS) were challenged with various concentrations of each allergen in its native and processed (boiled in PBS for 10 min) forms. Cell degranulation caused by the allergen was monitored by measuring the release of β-hexosaminidase. All allergens (NIST milk, BLG, ALA, and αCAS) were able to induce the release of β-hexosaminidase, up to 43.1%. A decrease in % release of β-hexosaminidase was observed when cells were challenged with a decreasing concenration xi of the ALA and milk allergens. Boiling of nonfat milk, ALA, BLG and αCAS caused an increase in the % release of β-hexosaminidase from sensitized cells across antigen concentrations from 10-6 mg/mL to 1 mg/mL. In conclusion, this study demonstrated that the in vitro mediator release assay method may serve as a useful model to evaluate the impact of thermal processing on the allergenic potential of milk allergens.
M.S. in Food Safety and Technology, July 2014
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