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Title: Targeting metabolic vulnerabilities in breast cancer subtypes
Creator: Ogrodzinski, Martin Peter
Date: 2020
Collection: Electronic Theses & Dissertations
Description: Breast cancer is a highly prevalent and deadly disease. Globally, it is the most diagnosed cancer in women and is responsible for the most cancer-related deaths among women. Breast cancer is also a remarkably heterogeneous disease, with clear variability in clinical parameters including histological presentation, receptor status, and gene expression patterns that differ between patients. A significant amount of effort has been spent characterizing breast cancer into subtypes, with the main...
Show moreBreast cancer is a highly prevalent and deadly disease. Globally, it is the most diagnosed cancer in women and is responsible for the most cancer-related deaths among women. Breast cancer is also a remarkably heterogeneous disease, with clear variability in clinical parameters including histological presentation, receptor status, and gene expression patterns that differ between patients. A significant amount of effort has been spent characterizing breast cancer into subtypes, with the main goal of improving patient outcomes by: 1) designing targeted therapies, and 2) improving our ability to determine patient prognosis. While scientists have made significant strides in meeting these goals, we still lack targeted therapies for some subtypes of breast cancer, and current therapies often fail to provide a lasting cure. Thus, additional research is needed to improve patient care. One promising area in breast cancer research is cancer metabolism. Using metabolism as a therapeutic target is rapidly gaining traction, as it is now widely appreciated that cancer cells exhibit significant differences in metabolism compared to normal cells. The primary goal of this dissertation is to study the metabolism of distinct subtypes of breast cancer and identify metabolic vulnerabilities that can be used to effectively treat each subtype.This thesis will begin with a review of current classification strategies for breast cancer subtypes and knowledge regarding subtype-specific metabolism. It will also consider modern techniques for targeting breast cancer metabolism for therapeutic benefit. Breast cancer heterogeneity and metabolism are investigated using cell lines and tumors derived from the MMTV-Myc mouse model, which mimics the complexity observed in human disease. Cell lines derived from two histologically defined subtypes, epithelial-mesenchymal transition (EMT) and papillary, are used to establish clear metabolic profiles for each subtype. Metabolic vulnerabilities are identified in glutathione biosynthesis and the tricarboxylic acid cycle in the EMT subtype and nucleotide biosynthesis is determined to be a metabolic weakness in the papillary subtype. It is further shown that pharmacologically targeting each of these metabolic pathways has the greatest effect on reducing proliferation when used against the vulnerable subtype. These in vitro findings are then expanded upon by integrating genomic and metabolomic data acquired from in vivo tumors. In vivo experiments reveal that the EMT and papillary tumors prefer parallel pathways to generate nucleotides, with the EMT subtype preferring to salvage nucleotides while the papillary subtype prefers to produce nucleotides de novo. CRISPR/Cas9 gene editing is used to functionally characterize the metabolic effects of targeting nucleotide salvage and de novo biosynthesis in the EMT and papillary subtypes, and determine that targeting the preferred pathway of each subtype is most effective at slowing tumor growth.Overall, this work demonstrates the power of using metabolism as a therapeutic target of breast cancer, and further shows that metabolic vulnerabilities specific to individual subtypes can be used effectively to guide personalized medicine.
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Title: Advances in oscillometric blood pressure measurement
Creator: Chandrasekhar, Anand
Date: 2019
Collection: Electronic Theses & Dissertations
Description: High blood pressure (BP) is a major cardiovascular risk factor that is treatable, yet hypertensionawareness and control rates are low. Ubiquitous BP monitoring technology could improve hypertensionmanagement, but existing devices require an inflatable cuff and are not compatible withsuch anytime, anywhere measurement of BP. Oscillometry is the blood pressure (BP) measurementprinciple of most automatic cuff devices. We extended the oscillometric principle, which is usedby most automatic cuff...
Show moreHigh blood pressure (BP) is a major cardiovascular risk factor that is treatable, yet hypertensionawareness and control rates are low. Ubiquitous BP monitoring technology could improve hypertensionmanagement, but existing devices require an inflatable cuff and are not compatible withsuch anytime, anywhere measurement of BP. Oscillometry is the blood pressure (BP) measurementprinciple of most automatic cuff devices. We extended the oscillometric principle, which is usedby most automatic cuff devices, to develop a couple of instruments to measure cuff-less BP usinga smartphone-based device and standalone iPhone application. As the user presses her/his fingeragainst the smartphone, the external pressure of the underlying artery is steadily increased while thephone measures the applied pressure and resulting variable amplitude blood volume oscillations.A smartphone application provides visual feedback to guide the amount of pressure applied overtime via the finger pressing and computes systolic and diastolic BP from the measurements.We prospectively tested the smartphone-based device for real-time BP monitoring in humansubjects to evaluate usability (n = 30) and accuracy against a standard automatic cuff-based device(n = 32). We likewise tested a finger cuff device, which uses the volume-clamp method of BPdetection. About 90% of the users learned the finger actuation required by the smartphone-baseddevice after one or two practice trials. The device yielded bias and precision errors of 3.3 and 8.8mmHg for systolic BP and [Special character(s) omitted]5:6 and 7:7 mmHg for diastolic BP over a 40 to 50 mmHg range of BP.These errors were comparable to the finger cuff device. Cuff-less and calibration-free monitoringof systolic and diastolic BP may be feasible via a smartphone. In addition, we tested the iPhoneapplication. The application yielded bias and precision errors of -4.0 and 11.4 mmHg for systolicBP and -9.4 and 9.7 mmHg for diastolic BP (n = 18). These errors were near the finger cuff deviceerrors. This proof-of-concept study surprisingly indicates that cuff-less and calibration-free BPmonitoring may be feasible with many existing and forthcoming smartphones.These devices use empirical algorithms, already descried in the literature, to estimate bloodpressure. Hence, the next objective was to establish formulas to explain three popular empiricalalgorithms- the maximum amplitude, derivative, and fixed ratio algorithms. A mathematicalmodel of the oscillogram was developed and analyzed to derive parametric formulas for explainingeach algorithm. Exemplary parameter values were obtained by fitting the model to measuredoscillograms. The model and formulas were validated by showing that their predictions correspondto measurements. The formula for the maximum amplitude algorithm indicates that it yields aweighted average of systolic and diastolic BP (0.45 and 0.55 weighting) instead of commonlyassumed mean BP. The formulas for the derivative algorithm indicate that it can accurately estimatesystolic and diastolic BP (<1.5 mmHg error), if oscillogram measurement noise can be obviated.The formulas for the fixed ratio algorithm indicate that it can yield inaccurate BP estimates, becausethe ratios change substantially (over a 0.5-0.6 range) with arterial compliance and pulse pressureand error in the assumed ratio translates to BP error via large amplification (>40). The establishedformulas allow for easy and complete interpretation of perhaps the three most popular oscillometricBP estimation algorithms in the literature while providing new insights. The model and formulasmay also be of some value towards improving the accuracy of automatic cuff BP measurementdevices.
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Title: Diagnostic tools for improving the amount of adaptation in adaptive tests using overall and conditional indices of adaptation
Creator: Ju, Unhee
Date: 2019
Collection: Electronic Theses & Dissertations
Description: In recent years, computerized adaptive testing (CAT) has been widely used in educational and clinical settings. The basic idea of CAT is relatively straightforward. A computer is used to administer items tailored for individuals to maximize the measurement precision of their proficiency estimates. However, the administration of CAT is not so simple. Those who administer CATs must, while trying to optimize an item selection criterion, consider a variety of practical issues such as test...
Show moreIn recent years, computerized adaptive testing (CAT) has been widely used in educational and clinical settings. The basic idea of CAT is relatively straightforward. A computer is used to administer items tailored for individuals to maximize the measurement precision of their proficiency estimates. However, the administration of CAT is not so simple. Those who administer CATs must, while trying to optimize an item selection criterion, consider a variety of practical issues such as test security, content balancing, the purpose of testing, and other test specifications. Such extraneous factors make it possible that a CAT might have so many constraints that in practice it is barely adaptive at all. This concern is at the forefront of the current study, which poses two key questions: How adaptive is a highly adaptive test really? How can the level of adaptation be improved? This study aims to develop three new statistical indicators to measure the amount of adaptation conditional on the examinees' proficiency levels in CAT. It also aims to evaluate the feasibility and utility of these adaptation measures in helping to diagnose and improve adaptivity that occurs during the CAT administration. Extending work done by Reckase, Ju, and Kim (2018), the proposed measures are based on three components-the differences in the locations between the selected items and the examinee's current proficiency estimates, the variations in the item locations administered to each examinee, and the magnitude of information that the test presents to each examinee. Hence, they can be used to assess adaptivity during the CAT process, as well as to identify differences in the level of adaptation for individuals or subgroups of examinees. To demonstrate the performance of the proposed adaptation indices, this study conducted analyses of real operational testing data from a healthcare licensure examination, as well as comprehensive simulation studies under various conditions that affect adaptivity in a CAT. The key findings of the study suggest that the proposed adaptation indices are likely to function as intended to sensitively detect the magnitude of adaptivity for a CAT over the proficiency continuum. These new measures shed light on how much adaptation of a given test occurs across individual proficiency levels or subpopulations. With some guidelines for the interpretation of these measures recommended in this study, the adaptation indices can also readily serve as diagnostic tools in practice for helping test practitioners design item pools and adaptive tests that support high adaptivity.
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Title: Reliable 5G system design and networking
Creator: Liang, Yuan (Graduate of Michigan State University)
Date: 2019
Collection: Electronic Theses & Dissertations
Description: The upcoming fifth generation (5G) system is expected to support a variety of different devices and applications, such as ultra-reliable and low latency communications, Internet of Things (IoT) and mobile cloud computing. Reliable and effective communications lie in the core of the 5G system design. This dissertation is focused on the design and evaluation of robust 5G systems under both benign and malicious environments, with considerations on both the physical layer and higher layers. For...
Show moreThe upcoming fifth generation (5G) system is expected to support a variety of different devices and applications, such as ultra-reliable and low latency communications, Internet of Things (IoT) and mobile cloud computing. Reliable and effective communications lie in the core of the 5G system design. This dissertation is focused on the design and evaluation of robust 5G systems under both benign and malicious environments, with considerations on both the physical layer and higher layers. For the physical layer, we study secure and efficient 5G transceiver under hostile jamming. We propose a securely precoded OFDM (SP-OFDM) system for efficient and reliable transmission under disguised jamming, a serious threat to 5G, where the jammer intentionally confuses the receiver by mimicking the characteristics of the authorized signal, and causes complete communication failure. We bring off a dynamic constellation by introducing secure randomness between the legitimate transmitter and receiver, and hence break the symmetricity between the authorized signal and the disguised jamming. It is shown that due to the secure randomness shared between the authorized transmitter and receiver, SP-OFDM can achieve a positive channel capacity under disguised jamming. The robustness of the proposed SP-OFDM scheme under disguised jamming is demonstrated through both theoretic and numerical analyses. We further address the problem of finding the worst jamming distribution in terms of channel capacity for the SP-OFDM system. We consider a practical communication scenario, where the transmitting symbols are uniformly distributed over a discrete and finite alphabet, and the jamming interference is subject to an average power constraint, but may or may not have a peak power constraint. Using tools in functional analysis and complex analysis, first, we prove the existence and uniqueness of the worst jamming distribution. Second, by analyzing the Kuhn-Tucker conditions for the worst jamming, we prove that the worst jamming distribution is discrete in amplitude with a finite number of mass points. For the higher layers, we start with the modeling of 5G high-density heterogeneous networks. We investigate the effect of relay randomness on the end-to-end throughput in multi-hop wireless networks using stochastic geometry. We model the nodes as Poisson Point Processes and calculate the spatial average of the throughput over all potential geometrical patterns of the nodes. More specifically, for problem tractability, we first consider the simple nearest neighbor (NN) routing protocol, and analyze the end-to-end throughput so as to obtain a performance benchmark. Next, note that the ideal equal-distance routing is generally not realizable due to the randomness in relay distribution, we propose a quasi-equal-distance (QED) routing protocol. We derive the range for the optimal hop distance, and analyze the end-to-end throughput both with and without intra-route resource reuse. It is shown that the proposed QED routing protocol achieves a significant performance gain over NN routing. Finally, we consider the malicious link detection in multi-hop wireless sensor networks (WSNs), which is an important application of 5G multi-hop wireless networks. Existing work on malicious link detection generally requires that the detection process being performed at the intermediate nodes, leading to considerable overhead in system design, as well as unstable detection accuracy due to limited resources and the uncertainty in the loyalty of the intermediate nodes themselves. We propose an efficient and robust malicious link detection scheme by exploiting the statistics of packet delivery rates only at the base stations. More specifically, first, we present a secure packet transmission protocol to ensure that except the base stations, any intermediate nodes on the route cannot access the contents and routing paths of the packets. Second, we design a malicious link detection algorithm that can effectively detect the irregular dropout at every hop (or link) along the routing path with guaranteed false alarm rate and low miss detection rate.
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Title: A cluster analysis comparison of garden activities in classical Chinese gardens and American gardens
Creator: Wang, Xiaoyi (Graduate of Michigan State University)
Date: 2019
Collection: Electronic Theses & Dissertations
Description: Activities that occurred in Chinese classical gardens and American gardens are an important part of their traditional culture. The purpose of this study is to explore the similarities and differences between Chinese classical gardens and American gardens. Six classical Chinese gardens in China and five American gardens in the United States were selected to test. Eighty-five possible activities were selected based on site visits and from historical documents. A method named principal component...
Show moreActivities that occurred in Chinese classical gardens and American gardens are an important part of their traditional culture. The purpose of this study is to explore the similarities and differences between Chinese classical gardens and American gardens. Six classical Chinese gardens in China and five American gardens in the United States were selected to test. Eighty-five possible activities were selected based on site visits and from historical documents. A method named principal component analysis with plots was applied to this research. After applying the variables into the software SAS, a number of eigenvalues were generated, and the first three eigenvalues representing almost 75% of the variance were used for further analysis. The result shows a distinctive difference between Chinese garden and American garden. The first principal component indicates the major element that differ the Chinese garden and American garden, with activities occurred only in Chinese gardens such as literati gathering, writing calligraphy, and examine antiques; and activities occurred only in American gardens such as barbecuing, making bonfires, and playing ball games. The second and third principal components explained the difference between Chinese gardens, which varies primarily because of the garden owner's lifestyle.
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Title: Evaluation and validation of soft robotic end effectors for produce harvesting
Creator: Dutcher, Zachary F.
Date: 2018
Collection: Electronic Theses & Dissertations
Description: Global population is expected to exceed 9 billion people by 2050 which will require a 70% increase in net global food production. 75% of global farm holdings are considered small at 2.5 acres or less. While contemporary industrial farming gains efficiency through increased mechanization, it comes with significant environmental costs. Industrial farming practices such as frequent tillage, monocropping and use of synthetic fertilizers, pesticides and herbicides are unsustainable practices that...
Show moreGlobal population is expected to exceed 9 billion people by 2050 which will require a 70% increase in net global food production. 75% of global farm holdings are considered small at 2.5 acres or less. While contemporary industrial farming gains efficiency through increased mechanization, it comes with significant environmental costs. Industrial farming practices such as frequent tillage, monocropping and use of synthetic fertilizers, pesticides and herbicides are unsustainable practices that will continue to degrade the surrounding ecosystem. Small scale farms present an opportunity to utilize regenerative farming practices; however, they are potentially challenging to scale up and expensive to automate with conventional automation solutions. In this thesis, soft robotic end effectors are explored as a potential means of harvesting on regenerative (as well as conventional) farms. Three end effector designs are testing for parameters including grasp variability, grasp effectiveness and real-world simulation on apple orchards at Michigan State University. Apple harvesting metrics including detachment force, diameter and weight have been collected for one hundred early harvest Spartan-Macintosh variety apples. Results of this evaluation show promise for the application of these low-cost technologies; however, much work is needed before a complete and viable soft robotic harvesting system is available.
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Title: What makes a space raced? : exploring writing centers as raced spaces
Creator: Faison, Wonderful
Date: 2018
Collection: Electronic Theses & Dissertations
Description: In this dissertation, What Makes a Spaced Raced?: Exploring Writing Centers as Raced Spaces, I interrogate the spatial design and object affect of the Writing Center and analyze how that design and object affect might effect those entering the Writing Center space. Because Writing Centers often position themselves as home or homelike spaces, the purpose of this project was to better understand (1) how Writing Center design may exclude marginalized bodies through its physical design and the...
Show moreIn this dissertation, What Makes a Spaced Raced?: Exploring Writing Centers as Raced Spaces, I interrogate the spatial design and object affect of the Writing Center and analyze how that design and object affect might effect those entering the Writing Center space. Because Writing Centers often position themselves as home or homelike spaces, the purpose of this project was to better understand (1) how Writing Center design may exclude marginalized bodies through its physical design and the various objects placed in the Writing Center, (2) how those exclusions are read by “outsiders” (those not working in the Writing Center space they critiqued), and (3) how Writing Centers can begin to design spaces that are read as more inclusive/accepting of marginalized bodies. By using Black womanism as both method and methodology, I designed comparative analysis of three Writing Centers in which tutors working in one Writing Center would interrogate a different Writing Center space. Using three Writing Center Sites, nine separate tutors—divided into groups of three—analyzed two separate sets photos of these three Writing Center sites. Participants analyzed both the unoccupied Writing Center Space and the occupied Writing Center to discern if the effect of a Writing Center space may be altered depending on who operates in the space. My findings indicate that race is read through a perception of class, e.g., the furniture, technology, and pictures/paintings participants marked as expensive suggested marginalized and working-class bodies would not seek tutoring services from or desire to be employed by the Writing Center.
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Title: Object location and shape estimation using a MIMO FMCW millimeter wave sensor
Creator: Lou, Yun
Date: 2018
Collection: Electronic Theses & Dissertations
Description: Autonomous systems such as self-driving cars and drones are going to transform our lives in many ways. One fundamental element of these systems is the accurate and robust sensing of the surrounding environments. Current solutions involve a multi-modal approach where varieties of sensors are utilized to achieve the best performance. Among all the sensing modalities, millimeter wave radar is playing a critical role due to its high resolution and the capability of sensing in the dark environment...
Show moreAutonomous systems such as self-driving cars and drones are going to transform our lives in many ways. One fundamental element of these systems is the accurate and robust sensing of the surrounding environments. Current solutions involve a multi-modal approach where varieties of sensors are utilized to achieve the best performance. Among all the sensing modalities, millimeter wave radar is playing a critical role due to its high resolution and the capability of sensing in the dark environment. As the cost, size and weight of millimeter wave radars decrease prominently in recent years, there is a significant opportunity to widely adopt it for a variety of sensing tasks.This thesis presents a MIMO FMCW millimeter wave radar system at 77-81 GHz band. It is a small-size and high-accuracy solution for sensing objects in the environment. Our system is designed to estimate the object's surface shape, orientation, curvature, boundaries, and 2D location by detecting the object's surface at multiple positions on a planned trajectory. We evaluated our system on a metal rectangular box and a metal cylinder. The experiment results show that our system is able to determine the surface type (planar or curved) correctly and achieve cm-level accuracy on the boundaries and location estimation. The orientation error is bounded to 2.14 degrees. The curvature estimation is highly accurate for the middle part of the curved surface.
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Title: Assessing bikeway design alternatives : DALMAC route centeral Michigan case study
Creator: Li, Yinliang
Date: 2018
Collection: Electronic Theses & Dissertations
Description: The objective of this thesis is to explore the differences and possibilities of bikeway design implemented with different treatments by examining the DALMAC bicycle camping tour. In the following steps, the thesis conducted series of analysis to select the final route by assessing three segments (Site A, Site B, and Site C) as study sites from DALMAC (b = 3). The investigation studied treatment including: 1) Existing Treatment, 2) Balance Treatment, 3) Extremely Safe Treatment, 4) Extremely...
Show moreThe objective of this thesis is to explore the differences and possibilities of bikeway design implemented with different treatments by examining the DALMAC bicycle camping tour. In the following steps, the thesis conducted series of analysis to select the final route by assessing three segments (Site A, Site B, and Site C) as study sites from DALMAC (b = 3). The investigation studied treatment including: 1) Existing Treatment, 2) Balance Treatment, 3) Extremely Safe Treatment, 4) Extremely Enjoyable Treatment, and 5) Extremely Environmental Treatment (k = 5). In order to test the differences among treatments statistically through Freidman Test of variances, there is a scoring criteria consisting of 30 questions. As a result, this data indicated that at least one treatment yield different values among all treatments (p ≤ 0.005 or p ≤ 0.001). Furthermore, among all treatments across 3 sites, the Extremely Enjoyable Treatment statistically performed best (p ≤ 0.05). In conclusion, this thesis investigated the potential values of bicycle enjoyment for a specific segment of DALMAC route.
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Title: A method for employing qualitative data in the development of spatial agent-based models
Creator: Molen, Nicholas
Date: 2016
Collection: Electronic Theses & Dissertations
Description: Developers of agent-based models of socioecological systems are in a power-laden relationship with those they presume to model. It has often been the case that these developers do not inform their model with any sort of rich cultural data, and instead rely upon established methods from areas such as economics, laboratory psychology, and machine learning. While these methods can be effective, ignoring the perspective of the humans being represented in an ABM risks validation of that model for...
Show moreDevelopers of agent-based models of socioecological systems are in a power-laden relationship with those they presume to model. It has often been the case that these developers do not inform their model with any sort of rich cultural data, and instead rely upon established methods from areas such as economics, laboratory psychology, and machine learning. While these methods can be effective, ignoring the perspective of the humans being represented in an ABM risks validation of that model for the wrong reasons and a marginalization of the humans represented in the model. Qualitative data collection methods, such as the collection of narratives, can aid not only in the elucidation of cultural ecological complexity, but also in the anchoring of an ABM to the political and ecological perspectives presented. While qualitative methods might lead to ABMs with higher fidelity to their real-world counterparts without as many power issues, making use of qualitative data during model development can be quite challenging, and no clear general methods exist. This thesis proposes a method to utilize long-form key informant narratives in the development of spatial agent-based models by linking the textual analysis of source documents to multiple modeling steps utilizing mental mapping and Object-Process Methodology extended for Multi-Agent-Systems (OPM/MAS). To test this method, narratives from migrants during the American Dust Bowl were analyzed and used to construct grounded models. The resulting model of a migrant agent is simple, easily understood and implemented, and its components can be linked directly to elements in the source narratives.
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Title: Integration of planning, design, and construction to train 21st century urban professionals
Creator: Dalton, Robert
Date: 2016
Collection: Electronic Theses & Dissertations
Description: The built environment professions are struggling as budgets decrease and scope and importance increase. Attempting to save money, clients are turning to multidisciplinary offices for all-in-one service. Higher education can respond to these shifting trends by preparing the students for a growth mindset and openness to the ideas constructed by a team rather than an individual. Integrative learning may foster such minds. Integrative learning concerns the building of cognitive connections from...
Show moreThe built environment professions are struggling as budgets decrease and scope and importance increase. Attempting to save money, clients are turning to multidisciplinary offices for all-in-one service. Higher education can respond to these shifting trends by preparing the students for a growth mindset and openness to the ideas constructed by a team rather than an individual. Integrative learning may foster such minds. Integrative learning concerns the building of cognitive connections from one skill or piece of knowledge to the next. This study found cultural areas shared among professions as well as those distinct to one profession. These cultural attributes group into four categories: axiology, epistemology, methodology, and ontology. All professions rate learning (epistemology) the required skills best while they work in offices, rather than their time in higher education. Methodologies include the tasks accomplished to plan, design, and build a project and the tools used to do so. Each profession brings their own contributions to problem solving and uses varied software to accomplish their means. These contributions are highly related to the corresponding values (axiology), though mean ratings indicate a high value for a task even if it is not one’s own. The study concludes by assessing the products (ontology) that may be created by the professions most likely to work together. The teams coming together most often represent the professions of the exterior spaces, building and interior spaces, and the legal and real estate professions. Employers and educators alike may use this information to understand the differences among the professional cultures and how bridging these divides or allowing gaps to remain can impact the project delivery.
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Title: Enhancing item pool utilization when designing multistage computerized adaptive tests
Creator: Yang, Lihong
Date: 2016
Collection: Electronic Theses & Dissertations
Description: In recent years, the multistage adaptive test (MST) has gained increasing popularity in the field of educational measurement and operational testing. MST refers to a test in which pre-constructed sets of items are administered adaptively and are scored as a unit (Hendrickson, 2007). As a special case of Computerized Adaptive Testing (CAT), a MST program needs the following components: an item response theory (IRT) model or non-IRT-based alternatives; an item pool design; module assembly;...
Show moreIn recent years, the multistage adaptive test (MST) has gained increasing popularity in the field of educational measurement and operational testing. MST refers to a test in which pre-constructed sets of items are administered adaptively and are scored as a unit (Hendrickson, 2007). As a special case of Computerized Adaptive Testing (CAT), a MST program needs the following components: an item response theory (IRT) model or non-IRT-based alternatives; an item pool design; module assembly; ability estimation; routing algorithm; and scoring (Yan et al., 2014). A significant amount of research has been conducted on components like module assembly, ability estimation, routing and scoring, but few studies have addressed the component of item pool design. An item pool is defined as consisting of a maximal number of combinations of items that meet all content specifications for a test and provide sufficient item information for estimation at a series of ability levels (van der Linden et al., 2006). An item pool design is very important because any successful MST assembly is inseparable from an optimal item pool that provides sufficient and high-quality items (Luecht & Nungester, 1998). Reckase (2003, 2010) developed the p-optimality method to design optimal item pools using the unidimensional Rasch model in CAT, and it has been proved to be efficient for different item types and IRT models. The present study extended this method to MST context in supporting and developing different MST panel designs under different test configurations. The study compared the performance of the MST assembled under the most popularly studied panel designs in the literature, such as 1-2, 1-3, 1-2-2, and 1-2-3. A combination of short, medium and long tests with different routing test proportions were used to build up different tests. Using one of the most popularly investigated IRT models, the Rasch model, simulated optimal item pools were generated with and without practical constraints of exposure control. A total number of 72 optimal items pools were generated and the measurement accuracy was evaluated by an overall sample and conditional sample using various statistical measures. The p-optimality method was also applied in an operational MST licensure test to see if it is feasible in supporting test assembly and achieving sufficient measurement accuracy in practice. Results showed that the different MST panel designs achieved sufficient measurement accuracy by using the items from the optimal item pools built with the p-optimality method. The same was true with the operational item pool. Measurement accuracy was related to test length, but not so much to the routing test proportions. Exposure control affected the item pool size, but the distributions of the item parameters and item pool characteristics for all the MST panel designs were similar under the two conditions. The item pool sizes under the exposure control conditions were several times larger than those under no exposure control, depending on the types of MST panel designs and routing test proportions. The results from this study provide information for how to enhance item pool utilization when designing multistage computerized adaptive tests, facilitating the MST assembly process, and improving the scoring accuracy.
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Title: Compact, low-power microelectronic instrumentation for wearable electrochemical sensor arrays in health hazard monitoring
Creator: Li, Haitao
Date: 2016
Collection: Electronic Theses & Dissertations
Description: Biological and chemical hazards threaten human health and are of growing world concern. Wearable sensors offer the potential to monitor local exposure of individual users while enabling distribution across a global scale. However, achieving this goal is challenged by the lack of autonomous high performance sensors with the power and size features required for wearable implementation. Wearable sensors need sensing techniques having high-performance in power, sensitivity, and selectivity for...
Show moreBiological and chemical hazards threaten human health and are of growing world concern. Wearable sensors offer the potential to monitor local exposure of individual users while enabling distribution across a global scale. However, achieving this goal is challenged by the lack of autonomous high performance sensors with the power and size features required for wearable implementation. Wearable sensors need sensing techniques having high-performance in power, sensitivity, and selectivity for biological and chemical hazards within a small volume. The autonomous operation of wearable sensors demands electronics to intelligently analyze, store, and transmit the data and generate alerts, within the strict constraints of power, and size. Electrochemical sensors have many characteristics that meet the challenging performance requirements of wearable sensors. However, the electrochemical instrumentation circuits are too heavy, bulky, expensive and consume too much power for wearable applications. Modern complementary metal–oxide–semiconductor (CMOS) technology provides an ultra-small, low-cost, low-power and high-performance solution for wearable sensors. This dissertation investigates CMOS circuit design for wearable electrochemical sensor arrays in health hazard monitoring. Multiple electrochemical modes provide orthogonal data to sensor array algorithms to improve sensor sensitivity and selectivity. A unique multi-mode resource-sharing instrumentation circuit was developed to integrate amperometric and impedance sensing abilities, and share electronics components among recording channels, with reduced size, cost, and power. A wearable sensor array can measure multiple hazardous targets in a wide range of concentrations. To address the wide dynamic range of such a sensor array, a new CMOS amperometric circuit that combines digital modulation of input currents and a semi-synchronous incremental Σ∆ ADC was developed. The new circuit simultaneously achieves a combination of wide dynamic range (164 dB), high sensitivity (100 fA), high power efficiency (241 μW) and compact size (50 readout channels on a 3×3 mm2 chip) that is not available in any existing instrumentation circuits. While the circuits above addressed key challenges in gas sensors, electrochemical biosensors offer a different set of challenges. In particular, miniaturized biosensors based on nanopore interfaces, including ion channel proteins, have great potential for high-throughput biological study and wearable biosensing. However, they require electrochemical instrumentation circuits that are compact, low power, and highly sensitive, high bandwidth. To address this need, a shared-segment interleaved amperometric readout circuit was developed, and measurement results show it has superior performance in terms of power and area compared to other known current sensing circuits for the same biological targets. This circuit achieves 7.2 pArms noise in a 11.5 kHz bandwidth, over 90 nA bidirectional input current range with only 21 μW power consumption, and allowing over 400 channels to be integrated on a single chip. The combined results of this research overcome many challenges for the development of wearable electrochemical sensor array in health hazard monitoring applications.
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Title: Efficient and secure system design in wireless communications
Creator: Song, Tianlong
Date: 2016
Collection: Electronic Theses & Dissertations
Description: Efficient and secure information transmission lies in the core part of wireless system design and networking. Comparing with its wired counterpart, in wireless communications, the total available spectrum has to be shared by different services. Moreover, wireless transmission is more vulnerable to unauthorized detection, eavesdropping and hostile jamming due to the lack of a protective physical boundary.Today, the two most representative highly efficient communication systems are CDMA (used...
Show moreEfficient and secure information transmission lies in the core part of wireless system design and networking. Comparing with its wired counterpart, in wireless communications, the total available spectrum has to be shared by different services. Moreover, wireless transmission is more vulnerable to unauthorized detection, eavesdropping and hostile jamming due to the lack of a protective physical boundary.Today, the two most representative highly efficient communication systems are CDMA (used in 3G) and OFDM (used in 4G), and OFDM is regarded as the most efficient system. This dissertation will focus on two topics: (1) Explore more spectrally efficient system design based on the 4G OFDM scheme; (2) Investigate robust wireless system design and conduct capacity analysis under different jamming scenarios. The main results are outlined as follows.First, we develop two spectrally efficient OFDM-based multi-carrier transmission schemes: one with message-driven idle subcarriers (MC-MDIS), and the other with message-driven strengthened subcarriers (MC-MDSS). The basic idea in MC-MDIS is to carry part of the information, named carrier bits, through idle subcarrier selection while transmitting the ordinary bits regularly on all the other subcarriers. When the number of subcarriers is much larger than the adopted constellation size, higher spectral and power efficiency can be achieved comparing with OFDM. In MC-MDSS, the idle subcarriers are replaced by strengthened ones, which, unlike idle ones, can carry both carrier bits and ordinary bits. Therefore, MC-MDSS achieves even higher spectral efficiency than MC-MDIS.Second, we consider jamming-resistant OFDM system design under full-band disguised jamming, where the jamming symbols are taken from the same constellation as the information symbols over each subcarrier. It is shown that due to the symmetricity between the authorized signal and jamming, the BER of the traditional OFDM system is lower bounded by a modulation specific constant. We develop an optimal precoding scheme, which minimizes the BER of OFDM systems under full-band disguised jamming. It is shown that the most efficient way to combat full-band disguised jamming is to concentrate the total available power and distribute it uniformly over a particular number of subcarriers instead of the entire spectrum. The precoding scheme is further randomized to reinforce the system jamming resistance.Third, we consider jamming mitigation for CDMA systems under disguised jamming, where the jammer generates a fake signal using the same spreading code, constellation and pulse shaping filter as that of the authorized signal. Again, due to the symmetricity between the authorized signal and jamming, the receiver cannot really distinguish the authorized signal from jamming, leading to complete communication failure. In this research, instead of using conventional scrambling codes, we apply advanced encryption standard (AES) to generate the security-enhanced scrambling codes. Theoretical analysis shows that: the capacity of conventional CDMA systems without secure scrambling under disguised jamming is actually zero, while the capacity can be significantly increased by secure scrambling.Finally, we consider a game between a power-limited authorized user and a power-limited jammer, who operate independently over the same spectrum consisting of multiple bands. The strategic decision-making is modeled as a two-party zero-sum game, where the payoff function is the capacity that can be achieved by the authorized user in presence of the jammer. We first investigate the game under AWGN channels. It is found that: either for the authorized user to maximize its capacity, or for the jammer to minimize the capacity of the authorized user, the best strategy is to distribute the power uniformly over all the available spectrum. Then, we consider fading channels. We characterize the dynamic relationship between the optimal signal power allocation and the optimal jamming power allocation, and propose an efficient two-step water pouring algorithm to calculate them.
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Title: Enabling higher energy and power density lithium ion batteries through electrode design and the integration of solid-state electrolytes
Creator: Kim, Yunsung
Date: 2015
Collection: Electronic Theses & Dissertations
Description: At present, Li-ion technology is the leading battery chemistry to enable the large-scale adoption of electric vehicles. However, meeting the demands of hybrid and plug-in hybrid electric vehicles requires higher specific and volumetric energy density, faster charge rates, longer cycle life, and improved safety. A particular focus is on achieving high power density without compromising energy density. This dissertation seeks to determine the phenomena that couple energy and power density and...
Show moreAt present, Li-ion technology is the leading battery chemistry to enable the large-scale adoption of electric vehicles. However, meeting the demands of hybrid and plug-in hybrid electric vehicles requires higher specific and volumetric energy density, faster charge rates, longer cycle life, and improved safety. A particular focus is on achieving high power density without compromising energy density. This dissertation seeks to determine the phenomena that couple energy and power density and to develop solutions to simultaneously increase both. An engineered electrode design is proposed that improves Li-ion transport in thick high energy density electrodes, while suppressing the deleterious formation of Li metal dendrites during charging. Furthermore, a novel hybrid cell design is proposed employing Li7La3Zr2O12 (LLZO) ceramic electrolyte membrane technology, which acts as a physical barrier to prevent Li metal dendrite propagation. The overarching goal of this dissertation is to develop materials and materials processing technology to improve the performance and safety of Li-ion batteries.
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Title: Investigation of planar terahertz passive devices and coupling methods for on-wafer applications
Creator: Myers, Joshua Carl
Date: 2015
Collection: Electronic Theses & Dissertations
Description: In recent years, developments have pushed the cut-off frequencies of transistors near 1 THz, enabling for the first time the design of large bandwidth transmit/receive modules. While there has been a significant interest in the research community to implement these devices, many challenges have slowed such progress. Primarily, these challenges stem from the high dielectric and metal losses many materials display in the THz spectrum. However, to implement wafer-level integrated circuits in the...
Show moreIn recent years, developments have pushed the cut-off frequencies of transistors near 1 THz, enabling for the first time the design of large bandwidth transmit/receive modules. While there has been a significant interest in the research community to implement these devices, many challenges have slowed such progress. Primarily, these challenges stem from the high dielectric and metal losses many materials display in the THz spectrum. However, to implement wafer-level integrated circuits in the THz spectrum, efficient passive devices that are integration compatible must be developed. For any integrated system, many of the most important passive building blocks of the system are reduced to efficient waveguiding, filtering, and coupling between any active components, necessary measurement systems, and input sources. In this dissertation, efficient passive terahertz components, including waveguides, filters, and input couplers, are developed. First, a method of efficiently coupling THz radiation between commercial quasi-optical THz systems and integration compatible THz components is introduced. The primary method developed is the use of high-density polyethylene focusing probes which can be easily fabricated so that they are compatible with commercial THz systems. The efficiency of the probes are then investigated when used with a simple silicon-based dielectric waveguide. Next, dielectric ridge waveguides made of silicon are investigated for low loss THz wave propagation. A theoretical effective index method is applied to determine the modal propagation properties of the waveguides as well as the attenuation of the structures. FEM simulation is also carried out to verify these results. Various ridge waveguides made on silicon wafers are investigated through measurement and determined to provide low-loss waveguiding properties in the THz spectrum. The focus is then shifted to the design of thin-film integration compatible THz filters. These filters are designed with multi-objective evolutionary algorithms coupled with FEM modeling. Bandwidth, stopband characteristics, multi-resonance, and other properties of the filters are developed and improved through optimization. The filters are measured using a commercial THz system, and shown to match well with the optimized expectations.Finally, another waveguiding structure is introduced which is built with thin-metal periodic structures on thin-film substrates. These structures efficiently guide THz waves along the surface of the textured metal structures. With these structures, other passive THz circuits, such as power splitters and sensors, are also developed. The waveguiding structures, as well as power splitter, are measured in conjunction with the dielectric focusing probes developed previously, and show to provide high transmission properties at specific design frequencies. Throughout this dissertation efficient waveguides, filters, and coupling methods are introduced. These methods are compatible with current semiconductor fabrication techniques, enabling device realization directly on-wafer. In addition, all of the passive devices that are developed are simple to fabricate, as well as low-cost. Through the work presented in this dissertation, the realization of passive building blocks for on-wafer active THz circuits are developed, which in turn provides the possible realization of active on-wafer THz circuits.
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Title: Online teaching and faculty learning : the role of hypermedia in online course design
Creator: Knott, Jessica Lucille
Date: 2015
Collection: Electronic Theses & Dissertations
Description: Using semi-structured interviews, this study set out to explore how faculty experiences in reading, teaching, and technology inform their use of hyperlinks and hypermedia in online teaching, learning, and course design. Further, an exploration of how faculty learn new technologies as they develop their online courses serves as a lens through which to view course design and its evolution. Study findings reveal that the use of hypermedia in online course design reflects the reading preferences...
Show moreUsing semi-structured interviews, this study set out to explore how faculty experiences in reading, teaching, and technology inform their use of hyperlinks and hypermedia in online teaching, learning, and course design. Further, an exploration of how faculty learn new technologies as they develop their online courses serves as a lens through which to view course design and its evolution. Study findings reveal that the use of hypermedia in online course design reflects the reading preferences and practices of the faculty developing the course. Further, findings indicate that, even when formal faculty development programs are offered, faculty learning is extremely fluid, with heavy reliance upon the resources they can find easily and immediately as a means of learning new things. New teaching philosophies were rarely adopted, but new course structure elements and technologies were adopted if the faculty felt they would assist in the content delivery process. As a result, recommendations include the development of just-in-time resources for faculty, and the development of faculty development programs that allow for individualized assistance and transfer.
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Title: Theoretical and numerical study of swirling flow separation devices for oil-water mixtures
Creator: Motin, Abdul
Date: 2015
Collection: Electronic Theses & Dissertations
Description: Oil-water separation is a critical aspect of produced water treatment, oil spill cleanup, and refining of petroleum products. Hydrocyclones are commonly used in these operations. A hydrocyclone is a device that separates two phases based on centrifugal forces acting on the two phases. Conventional hydrocyclones possess a finite turndown ratio and are effective for removing droplets greater than approximately ten microns. The understanding of hydrodynamic phenomena that limit the turndown...
Show moreOil-water separation is a critical aspect of produced water treatment, oil spill cleanup, and refining of petroleum products. Hydrocyclones are commonly used in these operations. A hydrocyclone is a device that separates two phases based on centrifugal forces acting on the two phases. Conventional hydrocyclones possess a finite turndown ratio and are effective for removing droplets greater than approximately ten microns. The understanding of hydrodynamic phenomena that limit the turndown ratio is crucial for improving hydrocyclone performance and finding a device that is reliable, efficient, and that has the potential to decrease the environmental footprint of oil and gas production. In this work, a quantitative understanding of the turndown ratio of an individual class hydrocyclone has been developed. A computational search is applied for redesigning the geometry of different modules of hydrocyclone. In addition, the desirable attributes of a crossflow filter and a vortex separator are combined into one unit to develop a crossflow filtration hydrocyclone (CFFH) for enhancing separation.The hydrodynamic characteristics of single and multiphase flows encountered in hydrocyclones, the trajectories of dispersed droplets, interaction of phases that involve breakup and coalescence of dispersed droplets, and the geometry and operating principles that characterize the performances of a hydrocyclone are investigated based on computational fluid dynamic (CFD) simulations using the Eulerian-Lagrangian, the Eulerian-Eulerian, and a coupled CFD-PBM (Population balance method) approaches. Results show that the finite turndown ratio in conventional hydrocyclones is a hydrodynamic effect that depends on the length of reverse flow core. Tailoring of hydrocyclone geometry with hyperbolic swirl chamber and new underflow outlet geometry significantly increases the separation efficiency and improves the turndown. Based on a parametric study, a novel hydrocyclone design is proposed that is able to achieve desired separation efficiency by a unit operation and possesses a large turndown. CFD studies were also performed on CFFH devices and showed that the swirl can aid in removing droplets from the membrane/filter surface.The novel hydrocyclone identified provides a stable reverse flow core for an increased range of feed Reynolds numbers and yields less energy loss. With increasing the feed Reynolds number, the novel hydrocyclone gradually decreases the cut size (a size of droplet having 50% separation efficiency); this does not appear in a conventional hydrocyclone. For the feed Reynolds number of 60,000, the cut size in the novel hydrocyclone is less than 10 microns whereas the conventional hydrocyclone has a cut size of 65 microns and is ineffective for droplet less than 10 microns.
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Title: Impact of color on children's play behaviors
Creator: Safferman, Bridget Nicole
Date: 2015
Collection: Electronic Theses & Dissertations
Description: IMPACT OF COLOR ON CHILDREN’S PLAY BEHVIORSByBridget Nicole SaffermanThis research examines the effects of differently colored playground balls on the play behaviors of children between the ages of three and four. Color vision in human beings triggers certain physical and psychological responses that can influence behavioral changes; the goal of this observational study is to determine if these responses are strong enough to influence the type and durations of children’s play. This...
Show moreIMPACT OF COLOR ON CHILDREN’S PLAY BEHVIORSByBridget Nicole SaffermanThis research examines the effects of differently colored playground balls on the play behaviors of children between the ages of three and four. Color vision in human beings triggers certain physical and psychological responses that can influence behavioral changes; the goal of this observational study is to determine if these responses are strong enough to influence the type and durations of children’s play. This observational study was conducted on children between the ages of 36 and 60 months old who were enrolled in a children’s daycare and child development research facility. Results of this study produced trends that indicate that certain colors do have an impact on the level of activity in which children play, namely, that children exhibit a greater number of play behaviors on traditional playgrounds, but play longer on nature playgrounds. Additionally, trends suggested that red and yellow, warm colors, increase the number of active and low active play behaviors observed and blue, a cool color, increases the durations of play behaviors. This knowledge suggest that color could be a viable tool in designing play spaces to meet specific needs and promoting different play behaviors in childrenKeywords: Color, Children’s Play Behaviors, Children’s Play Durations, Level of Activity
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Title: Design criteria for the treatment of milking facility wastewater in a cold weather vertical flow wetland
Creator: Campbell, Emily Loraine
Date: 2014
Collection: Electronic Theses & Dissertations
Description: The wastewater produced by Michigan milking facilities is harmful to the environment and costly to treat. A field demonstration of a subsurface treatment wetland in mid-Michigan has had continual success and has proven the capacity of constructed wetlands to effectively and affordably treat milking facility wastewater in colder climates. However, the wetland's design was inefficient and over-sized. Data from two lab-scale wetlands were collected and analyzed in order to create sizing and...
Show moreThe wastewater produced by Michigan milking facilities is harmful to the environment and costly to treat. A field demonstration of a subsurface treatment wetland in mid-Michigan has had continual success and has proven the capacity of constructed wetlands to effectively and affordably treat milking facility wastewater in colder climates. However, the wetland's design was inefficient and over-sized. Data from two lab-scale wetlands were collected and analyzed in order to create sizing and design criteria for a cost-effective design.As a result, design and sizing criteria were created for two types of wash water: manure contaminated and manure free. Several types of nutrients were monitored, including phosphorus, organic matter, total nitrogen, ammonia, nitrate, and pH. Since nitrogen levels in the manure contaminated wash water was three times larger than that in the manure free wash water, different designs were needed, though both designs were successful at treatment of COD and nitrogen. Phosphorus treatment was adequate, but temporary, as the wetland media lost capacity with time. Clogging potential was also taken into consideration. Although the change in hydraulic conductivity was indiscernible in the lab wetlands, the field site, which has been in operation over five years, was examined and no sign of clogging was found in sampling.
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