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Three Essays on Risk Analysis in Agri-Food Supply Chains
No full textThis thesis consists of three separate chapters, which cover upstream and downstream of the agri-food supply chain. In the first chapter, I revisit the price and volatility transmission mechanism among natural gas, fertilizer, and corn markets between 2011 and 2021. The results turn out natural gas price returns in the short-term are significantly affected by its lagged returns from itself and corn markets, and it will be affected by its lagged return sand fertilizer markets. In the second chapter, I explore the role of the collective reputation of online platforms in agri-food live streaming. The case study uses Taobao Live as an example and I explore the relationship between the collective reputation of online platforms and live streaming revenue. The main result shows that small agri-business owners who want to adopt live streaming to make money should launch their live streaming on a platform with a collective reputation. The third chapter analyzes the photo content in an online review platform. It studies the impact of photo content differences between business owners and customers on restaurant ratings. By constructing a new dataset and building the Latent Dirichlet Allocation model to find the latent of each photo, I found out the photo content in specific topics (the Dish, Protein Food, Dessert) has a positive impact on restaurant rating. It means that business owners can boost their rating by increasing the number of photos regarding these topics.masters, M.S., Agricultural Economics & Rural Soc -- University of Idaho - College of Graduate Studies, 2022-0
Divergence of iron and manganese oxidation state distributions, bonding environments, and mobility in mining-impacted lake sediments: column experiments
No full textThe mobility of a metal in mining-impacted sediments is determined by the environmental conditions that influence the metal’s oxidation state and bonding environment. Coeur d’Alene Lake of northern Idaho, USA, has been impacted by legacy mining practices that allowed the hydrologic transport of mining waste to the lakebed, which resulted in the deposition of an estimated 75 Mt of metal(loid)-rich sediments containing As, Cd, Fe, Mn, Pb, and Zn over the past 100+ years. Future lake conditions may include substantial algal blooms and deposition of additional algal detritus to the sediment-water interface, which may alter metal remobilization/retention during seasonal anoxia. Cores of the lake sediments were exposed to anoxic and anoxic + algae conditions for eight weeks. Over the eight-week period and at a location 12.5 cm deep in the sediments, anoxic and anoxic + algae conditions produced relatively stable Fe and Mn oxidation states and bonding environments. At a location 2.5 cm below the sediment-water interface, anoxic conditions promoted a relatively stable environment in which Fe and Mn oxidation states did not vary greatly during the experiment. At the 2.5-cm depth, the anoxic + algae condition substantially altered the Mn oxidation state distribution and bonding environment, but this condition did not strongly influence the Fe oxidation state distribution or bonding environment. The addition of algal detritus increased the presence of Mn3+, at select times produced Mn4+, altered the Mn bonding environment, and induced a larger release of Mn from the sediments into porewater. This increased oxidation of Mn, change in Mn bonding environment, and additional release of Mn from the sediments under the anoxic + algae condition likely occurred because of the increased formation of organo-Mn complexes produced during enhanced enzymatic processes with the presence of the additional organic matter. The increased microbial activity and Mn mobility has the potential to increase the release of Mn from the sediments and into the lake water column.masters, M.S., Water Resources -- University of Idaho - College of Graduate Studies, 2022-0
The Perception of Autonomous Driving in Rural Communities
No full textThe project examines the perceptions of autonomous vehicles in rural communities. The definition used in this study to determine whether respondents were in rural areas came from the United States Department of Agriculture (USDA) and was described as “open countryside and settlements with fewer than 2,500 residents.” A survey was created and distributed to respondents across the United States and 1,247 valid responses were analyzed. Based on the responses, rural respondents were more likely than non-rural respondents to commute further if they owned a self-driving vehicle. Older people and those with lower levels of education tended to have lower levels of trust in self-driving vehicles. Male respondents were associated with a decrease in the relative probability of “never” purchasing an AV over “buy[ing] at some point” but also a decrease in the relative probability of being “unsure” over “buy[ing] at some point” when other variables were held constant. Lastly, rural and non-rural respondents had similar levels of trust when choosing self-driving vehicles over human driven vehicles.masters, M.S., Civil & Environmental Engr -- University of Idaho - College of Graduate Studies, 2022-1
Modern Control of Smart Power Grids
No full textThe desire to reduce the carbon emissions footprint caused by fossil-fueled power plants has increased penetration of renewable energy resources based distributed generating units, in particular photovoltaic plants and wind energy conversion systems, in the power system network. Furthermore, the topology and architecture of the power system have changed from one with large conventional generation to one with distributed architectures. This thesis describes microgrid architectures, their control strategies and the distributed generating units that are used to supply the microgrids. The modeling, design, and control for a wind energy conversion system are described. The work includes a doubly-fed induction generator combined with a battery energy storage system. Photovoltaic power represents most of the new microgrid power sources in the literature. Modeling and control of a solar photovoltaic system are also described in the thesis. An energy storage system is connected in parallel with the photovoltaic system. The battery overcomes the intermittent nature of both wind speed and solar irradiation levels. The proposed system is modeled and simulated in different scenarios to verify the proposed control system and its operation to control the active and reactive power and terminal voltage. Expansion of renewable energy resources with common control schemes that have low inertia to replace conventional generators tends to reduce the total system inertia. Reduction of the inertia could have a dramatic effect on power system stability. Converter control schemes that create virtual synchronous generators were adopted in the literature to address the inertia reduction and stability challenges. The power converters are controlled to emulate and improve the features of the traditional synchronous generator such as inertia and damping, to improve system stability. A proposed control strategy, mathematical model, and controller design will be described in this thesis. Applying a virtual synchronous generator works best with an energy storage system. A hybrid energy storage system composed of superconducting magnetic energy storage and a battery is used to smooth the system's power fluctuations. The superconducting magnetic energy storage system deals with the high rate of change of power fluctuation. On the other hand, the battery system deals with slower power fluctuations. This hybrid system reduces the stress on the battery by removing the transient and high rate of change of charging and discharging currents to increase lifetime. Furthermore, virtual synchronous generator parameters can be set according to the desired and best performance without being limited by the characteristics of a physical synchronous generator, Moreover, these parameters and constants affect the sizing of the converter and the energy storage system size. When the inertia time constant increases, the system has larger amplitude power oscillations and it counteracts the frequency change. Also, the damping constant affects the system performance. When the damping constant increases, the system has lower amplitude power oscillations and it takes lower time to reach the new steady-state value. The simulation results describe how the inertia and damping constants affect the system operation and performance. Moreover, they show the power and energy required to achieve a desired performance of the virtual synchronous generator. However the superconducting magnetic energy storage system is more expensive than the battery, it may be more effective and cheaper in some applications such as in fast charge and discharge, and deep depth of discharge ones. Furthermore, virtual synchronous generator controllers combined with ESSs play a vital role to spread renewable energy generators and microgrid concepts. Hence, this helps to optimize using the available energy resources, and minimize conventional fuel consumption and greenhouse gas emissions.doctoral, Ph.D., Electrical and Computer Engineering -- University of Idaho - College of Graduate Studies, 2022-1
Monitoring the Ambient Seismic Field to Track Groundwater at a Mountain-Front Recharge Zone
No full textThe heterogeneity of the fractured-basalt and interbedded-sediment aquifer along the eastern margin of the Columbia Plateau Regional Aquifer System has presented challenges to resource managers for quantifying recharge. Previous studies indicated recharge pathways in alluvial sediments atop a mountain-front interface upgradient of the basalt flows. In this sedimentary zone, six seismic stations were deployed for one year to detect low-frequency seismic waves that could be correlated to changes in groundwater recorded by a well transducer near the center of the seismic station network. Sufficient waveforms were recorded at each station to determine changes in wave velocities between station pairs and correlate these changes to groundwater levels. The velocity-groundwater relation at each station pair allowed for estimation of daily groundwater flux beneath the seismic station network. Existing hydrogeologic information was used to estimate hydraulic gradients and hydraulic conductivities, which allowed for calculation of the daily volume of recharge passing beneath the seismic stations and into the confined aquifer system. The daily recharge volumes across the seismic station network were summed for comparison of the total annual recharge calculated from the seismic wave velocities (154,660 m3) to a flow model calculation of recharge based on areal precipitation and infiltration/percolation to the area upgradient of the seismic station network (26,250 m3). The 6× greater recharge estimated from the seismic velocity changes for this portion of the recharge zone is attributed to preferential pathways of high hydraulic conductivity and greater depth associated with paleochannels beneath the seismic station network.masters, M.S., Water Resources -- University of Idaho - College of Graduate Studies, 2022-0
Mass Continuity Constraints on Ice Ablation in Greenland
No full textMass loss across the Greenland Ice Sheet (GrIS) margin is increasing, with dynamic ice flux into the oceans and negative surface mass balance (SMB) being the two main mechanisms of mass loss. In this study, we focus on the SMB component, particularly negative SMB changes in the marginal ablation zone. Currently, SMB models struggle to represent spatial and temporal ablation variations near the GrIS margin, and recent studies have recommended using in-situ measurements and new remote sensing datasets to improve model skill along the ice sheet boundary. We detail and demonstrate a new satellite-based mass budget approach for estimating ablation rates throughout the Upernavik Isstrøm (UI) and Kangiata Nunaata Sermia (KNS) outlet regions. From 2019-2021, we report 396 total ablation rates and uncertainties over nine seasonal, temperate periods, with average measurements of -2.13±3.59 cm/d at UI and -2.50±3.25 cm/d at KNS. Validation efforts using nearby Automatic Weather Station (AWS) observations from the Programme for Monitoring of the Greenland Ice Sheet (PROMICE) network are encouraging, as the ablation rates are within or closely reflect spatially bounded ablation observations. Our mass budget method also shows an ability to reproduce observed ablation rates ranging from ~0 to -6 cm/d. While the average uncertainty at UI and KNS is about ±3.4 cm/d, uncertainty analysis reveals ablation rates at slow-flowing areas, with low longitudinal and transverse stresses, can be estimated within ±2 cm/d. Further validation and uncertainty analyses may improve spatial confidence to where our method can be scaled across a considerable extent of the GrIS margin, without an AWS.masters, M.S., Geography & Geological Science -- University of Idaho - College of Graduate Studies, 2022-0
Method to Accelerate Student Proficiency in CSWP/CSWPA Solidworks Certification Exams and Fusee Mechanism Profile Analysis
No full textStudents in the University of Idaho’s Solid Modeling, Simulation and Manufacturing Capstone (ME 490) course utilize Solidworks, one of the most widely used 3D CAD software in industry, to take eight certification exams to demonstrate competency in the program. This course has seen an increase in required instructional material, so this thesis presents a pedagogical method of introducing classroom material for the purpose of maintaining student pass rates with reduced instructional time. Exam scores and pass rates for CSWP Segments 1-3 and CSWPA Drawing Tools, Weldments, and Sheet Metal exams were analyzed between 2015 and 2019 to establish a target that needed to be maintained. During this period, instruction consisted of a wide range of tutorials. A new system was introduced between 2020 and 2021 that involved inquiry questions but fewer tutorials. The footprint of instruction dedicated to these topics was cut in half. However. when exam scores and pass rates were analyzed for Spring 2021 and Fall 2021, exam scores were maintained. This innovation created space in ME 490 for advanced topics in surfacing and special preparation for the CSWE exam. This new emphasis greatly expanded personal confidence in student CAD skills and heightened their interest in design for manufacturing. Additionally, an analysis of a fusee mechanism is included to show how Solidworks can be used as a design tool and to determine the correct profile for the shape of a fusee to aid horologists and community clock makers in designing their clocks. Three mathematical solutions from the literature were analyzed and transformed for comparison. The Preisendorfer was selected as a baseline and all solutions were plotted along the length of the fusee. The greatest deviations in the forward marching solutions occurred at the smallest end of the fusee. The greatest deviations in the backward marching solutions occurred in regions where the slope of the fusee was greatest at the largest end of the fusee. The Preisendorfer solution is recommended for use by horologists as a starting point for a successful fusee manufacturing plan.masters, M.S., Mechanical Engineering -- University of Idaho - College of Graduate Studies, 2022-0
Encounter Rates and Catch-and-Release Mortality of Steelhead in the Snake River Basin
No full textSteelhead Oncorhynchus mykiss are ecologically, economically, culturally, and recreationally important throughout the Pacific Northwest. The potential influence of recreational fisheries on wild steelhead is poorly understood and is a function of the abundance of wild fish, how many are encountered by anglers (i.e., encounter rate), and the mortality of fish that are caught and released. In Idaho, estimates of wild steelhead encounter rates are derived using the number of wild and hatchery steelhead passing Lower Granite Dam, the number of hatchery steelhead harvested, and the number of hatchery steelhead caught and released. Currently, managers assume hatchery and wild steelhead have equal encounter rates and apply a 5% catch-and-release mortality rate to the portion of the wild steelhead population caught by anglers. I sampled, tagged, and released 1,277 spawn-year 2020 (SY2020) and 2,072 spawn-year 2021 (SY2021) adult steelhead at Lower Granite Dam with T-bar anchor tags and passive integrated transponder (PIT) tags to apply novel methods to estimate hatchery steelhead encounter rates and catch-and-release mortality. Tagged fish moved into fisheries where 312 SY2020 and 639 SY2021 fish were caught and reported by anglers. Estimated encounter rates were 30.2% (95% confidence interval; 22.2, 39.5) for wild fish and 57.4% (20.7, 87.4) for adipose-clipped fish in SY2020. In SY2021, encounter rates were 37.0% (31.9, 43.6) for wild fish and 52.4% (44.9, 59.9) for adipose-clipped fish. Differences in survival of caught steelhead and those not reported as caught were evaluated using detections at various locations (e.g., PIT arrays, weirs). Based on this analysis, catch-and-release mortality of wild fish tagged with high reward tags (i.e., US 200 tags) was 3.9% (95% credible interval; 0.2, 16.0) and averaged 3.8% (± SE; ± 8.1%) across all reward values. Results of my research provide important information that will be useful in guiding management of hatchery and wild steelhead in Idaho and the region.masters, M.S., Natural Resources -- University of Idaho - College of Graduate Studies, 2022-0
Detecting Code Injections in Noisy Environments Through EM Signal Analysis and SVD Denoising
No full textThe widespread of embedded devices in virtually all types of critical applications has rendered them a lucrative target for attackers and evildoers. However, modifying traditional well-known perimeter protection mechanisms such as Intrusion Detection Systems to function in corresponding devices is not a trivial task. The main challenges revolve around Random Access Memory (RAM) memory and processing limitations. Recently, the analysis of electromagnetic emanations has gathered the interest of the research community. Thus, analogous protection systems have emerged as a viable solution for providing external, non-intrusive control-flow attestation for resource-constrained devices. Unfortunately, the majority of current work fails to account for the implications of real-life factors, predominantly the impact of environmental noise. In this work, we introduce a framework that integrates Singular Value Decomposition (SVD) along with outlier detection mechanisms for discovering malicious modifications in the execution of embedded software even under variable conditions of noise. Our proposed framework achieves near-perfect accuracy, i.e., above 99% AUC score of even minimal and unknown code injection attacks in moderately noisy environments, e.g., 0 SNR, and maintains high detection accuracy, i.e., above 93% AUC score for unseen attacks, even under extreme noise conditions, i.e., -10 SNR. To the best of our knowledge, this is the first time this realistic limiting factor, i.e., environmental noise, has been successfully addressed in the context of EM-based anomaly detection for embedded devices.masters, M.S., Computer Science -- University of Idaho - College of Graduate Studies, 2022-0
Modeling and Exploring Consumer Demand and Firms Investment Decisions
No full textThe focus of this thesis is on modeling and exploring both firm investment decisions and consumer demand. The research presented analyzing three unique cases, two in which firm investment is the focus and take a theoretical approach to modeling firm investment decisions and a third case that empirically models and evaluates consumer demand. Firm investment is estimated in the cases of League Profit and Market sizes, with a focus in evaluating how teams choose the optimal market for league expansion and relocation then in the setting of a hypothetical food court in which vendors either compete or collude with on another and the investment choices made to optimize both the court and vendor returns. Consumer demand is investigated through modeling the market for different vodka types sold in the state of Idaho, presenting the unique structure of each market independently and analyzing how consumers of a given vodka chose to compliment and/or substitute their consumption of their choice alcohol with the alternatives available to them. Beginning with our exploration on league market size and profitability; it is often assumed that sports leagues should have teams in the largest markets. However, our model shows that, depending on talent investment's role in team revenue, this is not necessarily true. Heterogeneity in markets sizes can not only decrease costs, but can also increase expected league revenue. Having a smaller market leads to an expectation that the large market team will win and creates less competition for playing talent. This creates a situation where leagues may prefer expansion teams to be in smaller markets or they want teams to relocate to smaller markets. Although there could be caveats, such as changes in consumer demand due to a decrease in competitive balance, greater market size differences can lead to higher league profits under general conditions. Moving forward our paper next evaluates firm investment in the unique case of food courts. Employing our model to examines food courts, where vendors are competing with each other for a fixed number of consumers. This case may arise when consumers are traveling and patronize a food court, or if the destination is a food court. A contest success function is used to describe consumers' choices, as well as vendor investment and profitability. Using a contest success function allows for varying degrees of substitution between the vendors. Substitution can be a function of location or product space. The model analyzes revenue sharing and changes in product differentiation when aggregate demand for the food court is fixed. The model is also examined if the food court has a collective reputation that depends upon the average investments of each vendor. Switching gears, this paper next examines consumer demand; through the market for vodka in the State of Idaho, exploring consumer demand for and consumer consumption of vodka. Using data provided by the state of Idaho, vodka is classified into one of five distinct types, from here a model is developed and employed to explain the demand for vodka. Own price, price of substitutes (wine, beer, other vodka types, and all other liquor), consumer income, unemployment, and population are all employed in the regression. Month, year, location of the sale (Store ID number) and months in which Covid was a factor are also controlled for. This research provides some evidence that each individually classified vodka is a unique separate market from the summation of all vodkas as one market, and further, all alcohols as one market. With each specific type of vodka having its own unique demand and consumption behavior to be analyzed and modeled independently.masters, M.S., Agricultural Economics & Rural Soc -- University of Idaho - College of Graduate Studies, 2022-0