Digital Commons Network^™

Numerical Simulation Of Water Tank Solidification In A Firefighting Aircraft Under High-Altitude Cold-Soak Conditions, Guanmian Liu, Zhihang Cheng, Hejun Qin, Kangzhi Yang, Qing Wen, Kun Gao

Journal of System Simulation

Abstract: A systematic numerical simulation study was conducted to address the issue of internal water tank solidification in firefighting aircraft under high-altitude low-temperature conditions. Based on computational fluid dynamics methods, a solidification-melting model considering fluid-structure interaction heat transfer and phase change processes was adopted. Through reasonable simplification of the complex geometric model, a quasi-three-dimensional computational model suitable for engineering analysis was developed. The influence laws of key parameters, including high-altitude cold-soak temperature, ground initial water temperature, and cold-soak time, on the freezing characteristics of the water tank were investigated. Combining with the parameter influence laws, a safety criterion using the …

Combat Effectiveness Evaluation Of Anti-Ship Missiles For Intelligent Autonomous Recognition, Long Zhang, Xuanming Feng, Zhen Lei, Bo Yang, Ying Wang

Journal of System Simulation

Abstract: To address the core issues of poor adaptability of static fusion strategies in existing recognition models, as well as the simplistic evaluation system and its disconnection from dynamic confrontation requirements, a practical four-dimensional evaluation system encompassing "recognition accuracy, antijamming stability, decision timeliness, and modal complementarity" was constructed, and an operational effectiveness composite index (OECI) capable of dynamically adapting to tactical scenarios was proposed. A multimodal dynamic attention fusion network (MDA-Net) for anti-ship missiles in complex confrontation environments was designed. Through heterogeneous feature decoupling, dynamic weighting of cross-modal attention, and a hierarchical gating decision mechanism, the autonomous evaluation and adaptive …

Infrared Image Generation Method Based On Improved Cyclegan, Qiqi Jin, Xiang Zhang, Li Gao, Lin Zhang, Junliang Yan, Peiyao Li

Journal of System Simulation

Abstract: To address the problems in current infrared image generation such as insufficient contrast between target and scene, excessively large discrepancies from real scenes, indistinct thermal source features, and great difficulty in constructing measured infrared image datasets, an improved CycleGAN-based infrared image generation method was proposed. By optimizing the network structure of the generator and adding a non-local module and a CBAM convolutional attention mechanism into the generator, the extraction capability of CycleGAN for infrared features was enhanced, enabling the network to capture the subtle features of targets more accurately; a perceptual loss function was introduced to improve the detail …

Human-Centered Electric Vehicle Adoption Framework For Smart Mobility: Modeling Perceived Range And Charging Anxiety As A Psychological Barrier, Fatemeh Nazari, Abolfazl (Kouros) Mohammadian, Thomas Stephens

Civil Engineering Faculty Publications

Electric vehicles (EVs) offer a transformative pathway toward reducing the environmental, economic, and health-related externalities of internal combustion engine vehicles in urban settings. Despite substantial advances in battery technology, charging infrastructure expansion, and supportive policy incentives, EV penetration remains limited which poses challenges for smart and sustainable mobility planning. A critical yet insufficiently modeled barrier to adoption lies in the psychological perceptions surrounding electric driving range and charging reliability, which is commonly framed as “range anxiety,” but more broadly reflecting perceived range and charging anxiety. To address this gap, this study introduces a latent psychological construct capturing individuals’ perceived range …

Optimal Scheduling Of Virtual Power Plants Considering Photothermal Power Stations And Hydrogen Energy Utilization, Yousong Chen, Ruofa Cheng, Yi Liu, Yi Zhang, Zhihao Zuo

Journal of System Simulation

Abstract: To enhance the operational stability and low-carbon performance of virtual power plants (VPPs) with high shares of renewable energy, a coordinated dispatch model integrating concentrated solar power (CSP) plants with power-to-gas (P2G) and carbon capture is developed. An optimal VPP scheduling strategy is proposed, combining a stepped carbon trading mechanism with a compensation coefficient and dynamic hydrogen blending. To address multi-source uncertainties in wind power, CSP power, and loads, an envelope boundary model is used for simulation. Information gap decision theory (IGDT) is applied to provide customized solutions for decision-makers with different risk preferences. A bi-objective optimization model is …

Fault-Tolerant Control Method For All-Type Actuator Faults Of Evtol Aircraft, Juan Wang, Guorui Li, Zhiyong Fan, Huijie Chen

Journal of System Simulation

Abstract: To address all-type actuator faults, especially nonlinear distortion issues, in multi-rotor eVTOL aircraft, a novel fault-tolerant control method was proposed. A fault function was established at the rotor speed level, and a fault-tolerant control algorithm combining dynamic robust nonsingular fast integral terminal sliding mode with a high-order finite-time disturbance observer was designed to achieve fault-tolerant control through rotor redundancy allocation. The nonsingular fast integral terminal sliding mode algorithm was improved, and a dynamic system containing actuator faults and their derivatives was constructed via a dynamic surface to achieve system convergence within finite time, avoiding the singularity and chattering problems …

A Method For Assessing The Contribution Degree Of An Aviation Delivery System And Identifying Key Equipment, Xiaofeng Liu, Chengze Jiang, Xingyu Chen, Deyin Jiang, Bolin Shang, Bifeng Song

Journal of System Simulation

Abstract: Based on the delivery efficiency and delivery quality, a general aviation delivery system effectiveness evaluation model was constructed, and a calculation method of system contribution degree based on efficiency was given. By combining the system calculation experiment and simulation experiment based on agent-based modeling and simulation (ABMS), the design idea of the Monte Carlo simulation experiment for key equipment identification and equipment technology development trend analysis was sorted out, and the key equipment identification method based on ABMS and contribution evaluation was proposed. By taking the intercontinental long-range aviation delivery mission as an example, a variety of simulation experiments …

Optimization Of Node Deployment For Three-Dimensional Heterogeneous Wsn In Elongated Structural Space, Jiguang Yang, Jiuyuan Huo, Fang Cao, Cong Mu

Journal of System Simulation

Abstract: To achieve effective coverage of key monitoring points in an elongated structural space, a heterogeneous wireless sensor network(HWSN) deployment optimization method combining the virtual force algorithm(VFA) and multi-strategy improved whale optimization algorithm(MSIWOA), namely HVF-MSIWOA, was proposed. A dynamic adaptive weight mechanism and a t-distribution perturbation operator with heterogeneous degrees of freedom were designed, enabling the whale optimization algorithm(WOA) to balance global exploration and local exploitation and jump out of local optima; combining the topological characteristics of the elongated space and node density distribution, an adaptive virtual force distance threshold between heterogeneous nodes was constructed; the mapping relationship between network …

Three-Dimensional Gaussian Reconstruction Of Large-Scale Scenes Under Multi-View Geometry Constraints, Haohao Cui, Yanqiang Di, Qing Liu, Xianguo Meng

Journal of System Simulation

Abstract: To enhance the geometry reconstruction quality of the GS algorithm in large-scale scene reconstruction, an optimization method constrained by multi-view geometry reconstruction results was proposed. 2D Gaussian planes were used as geometric primitives to overcome depth anisotropy, and dense depth maps generated by DUSt3R and aligned by sparse point clouds were introduced as constraints. By designing a multi-stage optimization strategy that decouples geometry and rendering, the gradient conflict problem in multi-objective training was solved. Experiments on the MatrixCity dataset indicate that the method surpasses comparison methods in related indicators of geometry reconstruction quality and rendering quality in large-scale scenes. …

Effect Of Rheology Modification On Fiber Orientation And Dispersion In 3d-Printed Ultra-High-Performance Concrete, Haodao Li, Alfred Addai-Nimoh, Seongho Han, Kamal H. Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The extrusion process in 3D concrete printing (3DCP) facilitates horizontal alignment of steel fibers along the printing direction, thus enhancing the load-bearing capacity of printed elements. However, such shear-induced fiber alignment is highly sensitive to rheological properties. This study investigates how variations in dynamic yield stress (τd) and plastic viscosity (μ), influence the extrudability, fiber orientation and dispersion, and anisotropic mechanical behavior of ultra-high-performance concrete (UHPC). Five viscosity-modifying agent (VMA) types were incorporated at two content levels to modify the rheology of printable UHPC. Results showed that moderate VMA additions improved printability, whereas excessive contents markedly increased τd and μ; …

Reframing Soil Freezing As An Unsaturated Process, Antai Dong, Xiong Zhang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Soil freezing and frost heave are inherently unsaturated soil phenomena. However, most existing numerical models are based on saturated soil mechanics or assume full saturation. This simplification introduces conceptual inconsistencies, requires modifications that violate fundamentals in soil mechanics and fluid mechanics, and often leads to the use of self-conflicting soil properties. To overcome these limitations, this study develops a physically consistent, fully coupled thermohydraulic model for soil freezing grounded in modern unsaturated soil mechanics. A soil freezing characteristic surface (SFCS) is introduced to represent unfrozen water content in partially frozen soils as a function of both suction and temperature. Recognizing …

High-Throughput Characterization Of Creep In Additively Manufactured 316l Stainless Steel, Raushan Kumar Singh

All Graduate Theses and Dissertations, Fall 2023 to Present

Advanced materials are widely used in industries such as nuclear energy, aerospace, and automotive engineering, where components are exposed to extreme temperatures and stresses over long periods of time. As new materials continue to emerge, researchers need efficient ways to evaluate their mechanical performance so they can be used safely and effectively. Among several mechanical challenges, creep is a major concern in these conditions. Creep is a type of mechanical failure in which materials gradually deform when exposed to high temperatures and constant load. Conventional methods for evaluating creep typically involve testing a single specimen at a time, which can …

Toward Risk-Informed Design Of Supercooling Heat Exchangers: Statistical Inference And Experimental Investigation Of Heterogeneous Ice Nucleation, Daniel B. Gardner

All Graduate Theses and Dissertations, Fall 2023 to Present

Ice-based cooling storage systems can reduce electricity costs and grid strain by making ice during off-peak hours and using it for air conditioning during the day. One promising design works by chilling water below its freezing point as it flows through a heat exchanger, then allowing it to freeze in a separate storage tank. The challenge is that the chilled water can freeze prematurely inside the heat exchanger itself, blocking the flow and shutting the system down. Preventing this unwanted freezing requires understanding how and where ice begins to form on surfaces, a process called nucleation.

This dissertation investigates ice …

Strain Monitoring And Site Characterization At Birds Landing From Transmission Tower Implosions Recorded Using Das And Nodal Stations, Prajwal Panthi

All Graduate Theses and Dissertations, Fall 2023 to Present

When two old electrical transmission towers in the Sacramento River Delta in California were demolished by Pacific Gas and Electric Company, Utah State University saw an opportunity hiding inside the demolition. Because one of the towers stood close to the Sacramento River and its protective levee, they used the controlled collapse not only to monitor strains in the levee and surrounding ground, but also to learn what lied beneath the ground surface.

To capture this event, the researchers buried a 1.4-kilometer fiber optic cable along the ground and connected it to a system called Distributed Acoustic Sensing (DAS), which can …

Time-Frequency Analysis Of Arterial Pulse Signals Of Cardiovascular Disease Patients Measured By A Microfluidic-Based Tactile Sensor, Md Mahfuzur Rahman

Mechanical & Aerospace Engineering Theses & Dissertations

This dissertation presents a single-degree-of-freedom (SDOF) based time–frequency analysis framework that can simultaneously extract a comprehensive set of cardiovascular autonomic indices from arterial pulse wave recordings obtained at rest and post-exercise, supporting non-invasive monitoring of autonomic recovery during cardiac rehabilitation. The framework rests on three technical contributions.

First, an SDOF analytical model of motion artefacts quantifies two physically distinct distortion mechanisms: additive baseline drift and Time-Varying System Parameter (TVSP) generated distortion of the Tissue-Contact-Sensor (TCS) stack. Baseline drift is slowly varying and removable by filtering; TVSP distortion rides on all harmonics of the true pulse signal and cannot be removed …

Evaluation Of Ostomy Pouching Change Practices Among Hospital-Based And Community-Based Nurses, Hannah Gerlach

All Theses

An estimated 725,000 to 1 million Americans are living with an ostomy and depend on ostomy pouching systems as part of their daily care. Effective ostomy management requires regular pouch changes and consistent skin care to prevent peristomal skin complications. Many individuals living with an ostomy face long-term challenges in managing their ostomy care, which can negatively affect their health-related quality of life. There is a need to understand how professional experience across different care environments, such as hospital-based and community-based settings, influences ostomy nursing care practices.

This study evaluates how nurses working in hospital-based settings and community-based settings perform …

Developing A Rapid Urban Forest Assessment System For Sustainable City Greenification, Daniel Gonzalez

Master's Theses

This thesis presents the Rapid Urban Forest Assessment (RUFA) system, a web-based platform that integrates urban tree inventories and aerial tree detection to assess forest health across California’s census-designated places. RUFA combines inventoried tree records with coordinates detected from high-resolution multispectral imagery using convolutional neural networks, then computes a composite RUFA Score from four metrics: canopy cover percentage, trees per capita, tree diversity (TD-50), and tree evenness. The thesis addresses two engineering challenges in building the dashboard: querying and aggregating over seven million tree records in real time, and rendering spatial summaries at multiple zoom levels without recomputing cluster assignments …

Optimal Management Of Electric Vehicle Fast Charging Stations Via Lyapunov Optimization And Reinforcement Learning, Mohammad Hossein Abbasi

All Dissertations

The transportation sector is responsible for 28% of global energy-related emissions, with road transport accounting for most of these emissions. While electric vehicles (EVs) are essential for decarbonizing transportation, widespread adoption depends on fast, efficient charging. Fast charging reduces charging time but accelerates battery degradation, whereas slow charging increases range anxiety. In addition, fast charging stations (FCSs) impose significant stress on distribution grids, making their operation a critical challenge. Optimizing FCS operation can conflict with EV fast-charging objectives, yet existing research largely treats these problems independently despite their strong interdependence.

Current fast-charging methods focus on individual cells or small battery …

Investigating The Impacts Of Information Framing And Representation On Multi-Stakeholder Decision-Making For Tradespace Exploration, Meredith G. Sutton

All Dissertations

Tradespace exploration (TSE) is a decision-making process used in engineering design to search through a tradespace, containing all potential solutions to a design problem and their performance evaluations, in order to select optimal or near-optimal solutions. Solution optimality is driven by a desire to maximize the overall utility of a solution, which often cannot be done without making tradeoffs or compromises. The TSE process requires vast amounts of information which can be difficult to generate and understand, often leading to challenges including information overload, delays in decision-making, and suboptimal decisions, even for the most experienced designers. To address the challenges …

Human-Centered Design Of Extended Reality For Learning Adoption, Effectiveness, And Collaborative Training Performance, Bhargav Upadhyay

All Dissertations

Extended reality (XR) technologies like virtual reality (VR) and augmented reality (AR) can be used for technical training to help students learn and practice complex tasks in a safe digital environment. Despite known benefits evidence is required to explore the effectiveness of these technologies to support student learning outcomes. Furthermore, technical training programs need evidence about when these tools improve learning, what are the barriers to adoption of these technologies, and how training should be designed by leveraging these technologies. This dissertation examined how XR technologies can support higher education and workforce training, specifically focusing on barriers and facilitators to …

A Hybrid Vsm-Des Approach For Bottleneck Identification And Reduction In A Continous One-Piece Flow Assembly System, Ana Sofia Rey Nevarez

Open Access Theses & Dissertations

Identifying bottlenecks in a production line is rarely as easy as pointing to the slowest station and assuming that's where the problem is. The real question is which stations moves the system when you change them. Lean manufacturing has been one of the initiatives that major companies in the U.S. have been trying to adopt to remain competitive. This thesis aims to understand the results of applying a combination of a Discrete-Event Simulation (DES) with a Value Stream Mapping (VSM), to find the bottleneck of a continuous one-piece flow assembly line of a tier-1 power management manufacturer from the El …

Green Pathways For Phytic Acid Extraction From Agriculture Residue For Flame-Retardant Applications, Laura Fronchetti Guidugli

Theses and Dissertations

The increasing generation of agricultural residues and the growing demand for sustainable chemicals and materials have intensified the interest in valorization of biomass-derived resources within a circular economy setting. Wheat bran, a major by-product of the cereal processing industry, accounting for approximately 14-30% of the wheat grain, represents an abundant and underutilized feedstock rich in phytic acid (PA, IP6), a phosphorus-containing biomolecule with applications in the food preservation, antioxidant, and flame-retardant sectors. However, conventional phytic acid recovery methods rely heavily on acid-assisted extraction processes that generate significant waste streams and environmental burdens. Therefore, the objective of this dissertation was to …

Balancing War And Peace In Taekwondo Athlete Development: A Multi-Criteria Coaching Decision Support Framework Using Leadership Scale For Sports And Fuzzy Ahp, King Harold A. Recto, Hazel Jade L. Antonio, Jhyrald Anthony P. Dalida

Electronics, Computer, and Communications Engineering Faculty Publications

Coaching effectiveness is frequently evaluated through competitive outcomes, with the assumption that coaching behaviors directly influence athlete performance. This study examined the relationship between perceived coaching behaviors and individual win percentage among collegiate Taekwondo athletes using the Leadership Scale for Sports (LSS). Descriptive statistics, correlation analysis, and regression analysis were conducted across five coaching dimensions: Training and Instruction, Democratic Behavior, Autocratic Behavior, Social Support, and Positive Feedback. Results showed that none of the coaching dimensions demonstrated a statistically significant relationship with win percentage. Although coaching behaviors did not significantly predict win percentage, the findings suggest that athlete development is shaped …

Wind Effects Induced By Multivortex Tornadoes On A Low-Rise Building, Yi Zhao, Guirong Yan, Tetsuya Takemi, John Van De Lindt

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Multivortex tornadoes contain two or more subvortices that orbit within a parent vortex and can generate highly intermittent and localized near-ground wind fields. This study investigates how tornado flow structure affects wind effects on a low-rise building using large-eddy simulations. One single-vortex tornado and three multivortex tornadoes with different subvortex configurations are examined by systematically varying swirl ratio. Tornado translation is modeled using a relative-motion framework in which the building traverses the vortex field. Aerodynamic force and moment coefficients are evaluated along the traversing path. Additional stationary simulations are conducted to examine repeated load amplification associated with subvortex passages. Compared …

Multistage Integrated Systems For Wastewater Treatment And Resource Recovery: A Systematic Process Design Framework, Mahsa Golmohammadi, Ensiyeh Taheri, Ratish Ramyad Permala, Sebastien Allard, Mehdi Khiadani, Amir Razmjou

Research outputs 2022 to 2026

The wastewater treatment paradigm is shifting from pollutant removal toward integrated systems that simultaneously achieve contaminant treatment and resource recovery. Despite extensive literature on individual technologies, systematic frameworks for designing multistage integrated wastewater treatment and resource recovery systems remain notably absent. This review addresses this gap by developing a comprehensive decision framework that guides designers from influent characterization through technology selection across pretreatment, main process, and post-treatment stages. The framework accommodates diverse integration strategies, ranging from fully unified treatment processes to stage-specific configurations where each treatment stage employs technologies tailored to its designated function. Rather than optimizing for a single …

Validation Of A Portable Electrochemical Sensor For Real-Time Soil Nitrate Monitoring In Cotton Rhizosphere, Mohammad Solaiman, Elvis D. Sangmen, Ali Reza Galib, Tushar C. Sarker, Anil C. Somenahally, Shawana Tabassum

Electrical Engineering Faculty Publications and Presentations

Soil nitrate (NO3) exhibits rapid spatial and temporal variability that conventional point-sampling methods cannot effectively capture, limiting timely nutrient management and plant stress detection. This study aimed to validate a low-cost, threedimensional- printed electrochemical NO3 sensor for continuous in-soil monitoring and to evaluate whether sensor-derived NO3 dynamics reflect plant physiological responses. For this purpose, cotton (Gossypium hirsutum L.) plants were grown in pots under greenhouse conditions. The sensor was evaluated in two sequential phases: an initial calibration phase to characterize sensor response across a broad NO3 concentration range, followed by a validation phase in the cotton plant rhizosphere. In the …

Genwriter 2.0: A Hybrid Case-Based And Llm Rewriting Approach For Mitigating Implicit Gender Cues In Text, Shweta Soundararajan, Sarah Jane Delany

Conference papers

Gendered language is the use of words or phrases that indicate an individual's gender. Although useful in some contexts, gendered language can reinforce gender stereotypes and introduce bias, particularly in machine learning models for tasks involving people such as recruitment or occupation classification. When textual content about individuals, such as biographies, contain gender cues, models can learn spurious associations between gender and other characteristics of individuals, such as profession, potentially resulting in unfair outcomes such as reduced hiring opportunities for women.

To address this challenge, we propose GenWriter 2.0, a hybrid approach that integrates Case-Based Reasoning (CBR) with Large …

Practical On-Device Intelligence For Resource-Constrained Embedded And Wearable Devices, Xiao Ma

Dissertations and Theses Collection (Open Access)

Embedded and wearable devices increasingly rely on deep neural networks to support intelligent sensing applications directly on the device. However, building practical on-device intelligence remains challenging throughout the deployment lifecycle. Before deployment, models must remain accurate despite severe memory, computation, and energy budgets, and a single device often needs to support multiple sensing applications without deploying a separate model for each application. After deployment, the device continues to operate in changing real-world environments, where shifts in data distribution can degrade the model’s performance over time, so the model must be able to adapt to such shifts efficiently.

The first challenge …

Water-Heated Maisotsenko Cycle Humidifiers: A Component-Level Study On Evaporation And Exit Brine Concentration, Omar Abdulfattah Farag Omar A. Farag

Renewable Mechanical Energy

Maisotsenko-cycle (M-cycle) Heat-and-Mass Exchangers (HMXs) are usually assessed as part of complete cooling or desalination systems, which makes the behaviour of the humidifier itself difficult to distinguish. Here, a validated model is used to examine a water-heated M-cycle humidifier as an independent component. Inlet saline-water temperature, ambient temperature, Relative Humidity (RH), and water-to-air Mass-flow Ratio (MR) were varied, and performance was described by Water Evaporation Rate (WER), outlet-air specific humidity, and outlet brine salinity. Water heating and a larger MR produced the strongest increase in moisture addition because they maintained a warmer water film and greater transfer potential. At fixed …

A Review Of The Safety Alert Systems In Commercial Vehicles: Implementation Challenges And Trends For Electronic Logic Devices And In-Cab Alerts, Md Sadman Islam, Deep Patel, Ahmed Sajid Hasan, Mohammad Jalayer, Abdul S. Ngereza, Emmanuel Kidando

Civil and Environmental Engineering Faculty Publications

The trucking industry is crucial to the US economy, accounting for 73.1% of the value, 71.1% of the cargo, and 42.0% of the ton-miles of all commodities transported nationwide. Despite its pivotal role, the industry is affected by high crash rates, with truck crashes resulting in 5,472 fatalities in 2023 alone. These incidents not only exhibit a higher fatality rate per vehicle mile compared with passenger cars but also cause substantial economic disruptions. Predominantly, these crashes are attributed to the failure to stop or slow down because of insufficient sight distances. In recent years, trucking companies have implemented various technologies, …