Digital Commons Network^™

Incremental Planar Nearest Neighbor Queries With Optimal Query Time, John Iacono, Yakov Nekrich

Michigan Tech Publications

In this paper we show that two-dimensional nearest neighbor queries can be answered in optimal O(log n) time while supporting insertions in O(log1+ϵ n) time. No previous data structure was known that supports O(log n)-time queries and polylog-time insertions. In order to achieve logarithmic queries our data structure uses a new technique related to fractional cascading that leverages the inherent geometry of this problem. Our method can be also used in other semi-dynamic scenarios.

The Role Of Fear And Predator Dependent Refuge On A Stage Structure Prey-Predator System, Ghaith Jassim Abdulsada, Hiba Abdullah Ibrahim

Baghdad Science Journal

The present paper investigates the role of fear and predator dependent refuge in the prey-predator system. The system describes the interaction between prey and a stage structure of predator that incorporates Holling II functional response. The predator splits into two compartments immature (juvenile) and mature (adult). The mature predators can hunt and reproduce but this capability is not found in the immature predators, the immature depend on their parents. The growth rate of prey decreases due to the existence of mature predators. The existence, uniqueness, and boundedness of the solution of the system are investigated. Three equilibrium points of the …

Applying Ceragenins In Translational Medicine: Activating Mesenchymal Stem Cells And Preventing Healthcare-Associated Infections, Aaron L. Zaugg

Theses and Dissertations

Healthcare-associated infections are a major global concern. Increased infections among vulnerable populations lead to millions of deaths, annually, complicated by the emergence of multi-drug resistant pathogens. These infections are often facilitated by medical devices serving as abiotic surfaces that facilitate the formation of biofilms. Notably, colonization of prostheses and other bone-associated medical devices can lead to corrective procedures, revisions and death. To address these issues, inspiration can be drawn from natural sources of bone health and defenses against infection. Cathelicidins are endogenous peptides involved in both bone maintenance and infection control. Ceragenins are small molecule mimics of cathelicidins with broad …

Relation Between Executive Functions, Ruminative Thinking Style, And Internalizing Symptoms In Neurodivergent Individuals., John Strom

Clinical Psychology Dissertations

Introduction: Neurodevelopmental disorders (NDD) are among the most common psychological disorders occurring in childhood (Bishop, 2010; Scandurra et al., 2019), and are commonly associated with a host of psychological challenges including deficits in executive functioning (Craig et al., 2016; Demetriou et al., 2019) as well as comorbid internalizing disorders such as depression and anxiety (Katzman et al., 2017; Kirsch et al., 2020; Simonoff et al., 2008). Research has suggested that executive function deficits may contribute to symptoms of depression and anxiety and that this relation may be mediated by ruminative thinking styles (Snyder et al., 2019; von Hippel et al., …

Invisible Intersections: Race, Adhd, And The Role Of Disciplinary Actions In Academic Outcomes, Miles Feller

Clinical Psychology Dissertations

Race is a marginalized identity linked to significant achievement gaps for Black and Latino students in the USA (de Bray et al., 2019). These students experience higher rates of exclusionary school discipline (ESD) than White and Asian peers (Aud et al., 2010; de Bray et al., 2019), with suspensions correlating to lower academic performance (Del Toro & Wang, 2022; Wang et al., 2023; Owens & Hinshaw, 2016). Additionally, developmental disabilities like ADHD intersect with these issues; despite narrowing racial disparities in diagnoses (Cénat et al., 2022; Fairman et al., 2020), access to treatment remains uneven (Baglivio et al., 2017; Coker …

Impact Of Perceived Stress And Trait Resilience On Mental Health Outcomes Related To Traumatic Stress Exposure, Ken Safley

Clinical Psychology Dissertations

Traumatic stress exposure is common and associated with a range of adverse psychological outcomes, including anxiety, depression, and posttraumatic stress disorder (PTSD). These effects are cumulative, with increased exposure linked to greater psychological distress. However, there is considerable variability in how individuals respond to trauma, suggesting the influence of cognitive and dispositional factors. Cognitive models of PTSD highlight the role of stressor appraisals in the development of psychopathology, while individual differences in protective factors, such as trait resilience, may buffer these effects. The present study investigated whether perceived stress mediates the relationship between trauma exposure and psychological outcomes, and whether …

Simulation Study On Adaptive Signal Control Of Deformed Intersection Based On Lstm-Gnn, Kun Chen, Liang Chen, Jiming Xie, Fengbo Liu, Taixiong Chen, Lukuan Wei

Journal of System Simulation

Abstract: Aiming at the traffic congestion at deformed intersections, an improved adaptive traffic signal control scheme based on deep learning is designed, the scheme integrates the adaptive signal control of LSTM and GNN at deformed intersections. LSTM is used to capture the dependence between time series traffic data, while GNN is used to construct a spatial interaction model between lanes. By integrating the information of time and space dimensions, the model can dynamically adjust the phase duration of signal lights according to real-time traffic conditions. The results indicate that the LSTM-GNN adaptive control scheme improves overall traffic throughput efficiency by …

Modeling And Simulation Of Dual-Podded-Propulsion Ship Motions, Bing Han, Yunhe Lin, Yuhang Chen, Zhouhua Peng

Journal of System Simulation

Abstract: Aiming at the autonomous navigation control requirements of the Dalian Maritime University's dual-purpose intelligent research and training ship "Xin Hong Zhuan," the design of the motion model for this dual-podded-propulsion ship is carried out. Utilizing an MMG model structure, it calculates the hull's hydrodynamic viscous forces, single/dual-propeller thrust, and hydrodynamic forces acting on the podded propulsion units. Based on data from sea trials and open-water propeller tests, straight-navigation resistance is derived via data fitting, while a method using simulated turning circle tests and PSO algorithms is proposed to determine some hydrodynamic coefficients, refining existing empirical formulas. The model's maneuvering …

Research On Scenario-Driven Virtual Simulation Test Method For Autonomous Escort Function Of Habor Tugs, Shijie Li, Jialin Li, Jialun Liu, Chengqi Xu, Zhilin Dong

Journal of System Simulation

Abstract: In order to comprehensively construct the test scenarios and verify the reliability of the tugboat autonomous companionway function, a scenario-driven virtual simulation test method for the tugboat autonomous companionway function is proposed. Based on the relative heading, relative speed and relative position of the target ship and the tugboat, the test cases of the tugboat autonomous companionway scenario are generated, and the complexity of the test cases is evaluated by using the fifthorder Bessel curve. The autonomous companion navigation function of the tug is verified through simulation experiments on the complex typical test scenarios without and with obstacles. The …

Dynamic Path Planning For Robotic Arms Based On An Improved Ppo Algorithm, Yuhang Wan, Zilu Zhu, Chunfu Zhong, Yongkui Liu, Tingyu Lin, Lin Zhang

Journal of System Simulation

Abstract: Aiming at the increased environmental uncertainties and more difficult modeling for robotic arm path planning in unstructured environments, an approach to dynamic path planning of robotic arms based on an improved PPO algorithm is proposed. In order to solve the problem that the input length of the state space is not fixed due to the change of number of obstacles in dynamic environment, an environmental state input processing method based on the LSTM network is proposed, and the network structure of PPO algorithm is also improved; a reward function is designed based on the artificial potential field method, and …

Self-Supervised Defect Detection Via Discriminative Enhancement-Based Distillation Learning, Zhiyuan Feng, Ying Chen

Journal of System Simulation

Abstract: To address the issues of scarce and unknown types of abnormal defect data and the lack of diversity in anomaly representation in conventional knowledge distillation defect detection methods, a self-supervised distillation learning method based on discriminative enhancement is proposed. An attention-based multi-scale feature fusion module is proposed, which enhances the capability of anomaly representation by amplifying the multi-scale feature differences between the student network and the teacher network. A discriminative network composed of a feature reweighting module and a decoder is designed to generate more accurate anomaly score maps by further emphasizing the anomaly features in the teacher network, …

Research On Robot Dynamic Obstacle Avoidance Method Based On Improved A* And Dynamic Window Algorithm, Yan Zhang, Binghua Li, Tao Huo, Rong Liu

Journal of System Simulation

Abstract: Aiming at the problems that the traditional A* algorithm has too many extension nodes and path turning points, and can't deal with dynamic obstacles in complex environment, a robot obstacle avoidance method combining improved A* algorithm and DWA algorithm is proposed. The A* algorithm improves the neighborhood expansion method and effectively avoids the problem of redundant nodes in the classical four-neighborhood expansion and the path through the obstacle in the eight-neighborhood expansion. A quadrant selection method is proposed, which can effectively reduce the number of extended nodes in the path search process. The redundant point elimination strategy is proposed …

A Study On Covid-19 Outbreak In Cook County Of Illinois, Suraj Powar

Research Papers

This study presents a mathematical model developed to better understand the transmission dynamics of COVID-19 and evaluate the effectiveness of different public health strategies. The model, called SEQIRD, includes of the disease such as exposure, quarantine, infection, recovery, and death. Using real case and death data from Cook County, Illinois, the model closely fits observed trends and captures both pre and post-lockdown dynamics with high accuracy.

Our results show that early intervention significantly reduces total infections, with lockdown imposed even a few days earlier preventing thousands of cases. Through sensitivity analysis, we also identify that parameters such as transmission rate, …

Investigation Of The Relationship Between Triglyceride Glucose Index And Metabolic And Hematological Parameters In Obese Individuals, Özge Baş Aksu, Feri̇de Özkara, Rifat Emral, Volkan Genç, Demet Çorapçioğlu, Mustafa Şahi̇n

Turkish Journal of Medical Sciences

Background/aim: This research examined the association between the triglyceride-glucose (TyG) index and metabolic, hepatic, and hematologic variables in a population of severely obese subjects, with a focus on the assessment of glycemic control.

Materials and methods: This retrospective study included 315 adult patients with a body mass index (BMI) ≥ 35 kg/m² who were evaluated for bariatric surgery. Participants were grouped according to HbA1c levels: those with HbA1c ≥ 6.5% and those with HbA1c < 6.5%. TyG, atherogenic index of plasma (AIP), fibrosis-4 (FIB-4), aspartate aminotransferase-to-platelet ratio index (APRI), and hematological inflammation markers were assessed and compared between groups. To investigate associations, correlation and regression analyses were conducted.

Results: Individuals with HbA1c ≥ 6.5% had significantly higher TyG, AIP, APRI, and FIB-4 values than those with lower HbA1c. The TyG index showed a strong …

Thermal Simulation For Ultrafast Laser In Multilayered Sample For Heat-Assisted Magnetic Recording Application, Haidar J. Mohamad, Basaad Hadi Hamza

Baghdad Science Journal

Heat-Assisted Magnetic Recording (HAMR) is a promising step in expanding hard disk capacity. This technique depends on the ultrafast laser to demagnetize the layer and record the data on a hard disk or any storage media. However, the recipe for the layers is challenging and gives a space to explore. The investigation of the effects of temperature profile and thermal gradient on the suggested sample FePt (8 nm)/MgO (8 nm)/SiO₂ (58 nm)/Si (9.32 E-7 m) for HAMR use was the focus of this study. The simulation of the multilayered gives a view of ultrafast laser behavior (power density 1.7923 …

Effect Of Surface Stress On Love Wave Propagation In A Rotating Initially Stressed Orthotropic Elastic Solid Half-Space With Impedance Boundary Conditions, Somaiah Kamidi, Venkateswara Rao Burugu, Srinivas Remidi

Baghdad Science Journal

This article aims to investigate the effect of material surface stress on the propagation of Love waves in a rotating, homogeneous, initially stressed orthotropic elastic solid with impedance-type boundary conditions. For deriving Love waves, the basic equations are solved with the help of the traditional wave solution method. Secular equations about Love waves are computed as a function of surface stress, rotation, and initial stress. The effects of initial compression and surface stress have been discussed numerically using MATLAB for a particular model.

Combining The Least-Squares Method With Touchard Polynomials For Solving Mixed Integro-Differential Equation, Hameeda O. Al-Humedi, Zahraa Adnan Jameel

Baghdad Science Journal

Using the well-known least-squares weighted residual method (LSM) in coupling with various degrees of Touchard polynomials (TPs), found the numerical solutions of Volterra–Fredholm integro-differential equations (VFIDEs) and mixed Volterra–Fredholm integro-differential equations (MIDEs) of the second kind. There exist many approaches that have evaluated the approximate solution of the integro-differential equations (VFIDEs (MIDEs)) like the Adomian decomposition method and modified Adomian decomposition method, Homotopy analysis method, Taylor polynomials, power series expansion and cubic Legendre spline collocation method. In this work, we presented a method based on combining LSM with TPs is an essential component of the suggested approach. By implementing such …

Modeling And Simulation Of Hybrid Traffic Flow Considering The Inherent Dynamics Of Cacc Vehicular Platoons, Xiujian Yang, Jingjing Huang, Xi Wang

Journal of System Simulation

Abstract: To investigate the characteristics of single-lane mixed traffic flow with the presence of cooperative adaptive cruise control (CACC) vehicle platoons, a modeling approach based on cellular automata is proposed. This method distinguishes between the car-following strategies of human-driven vehicles and CACC vehicles, incorporating dynamic inter-vehicle spacing within the platoon and actual control behaviors to construct a mixed traffic flow model with inherent dynamic properties. The model enables an in-depth analysis of the influence of platoon features, such as geometric formation, carfollowing control strategies, and platoon size, on the characteristics of mixed traffic flow. It also allows us to study …

Construction Method Of Digital Twin System For High-Low Temperature Test Chamber, Qinghua Chen, Zuoyou Liang, Weijuan Guan, Jiadong Ji, Ping Liu

Journal of System Simulation

Abstract: In view of the construction requirements of the digital twin system of the high-low temperature test chamber, the EMQX server with MQTT as the communication protocol is used for data transmission. Driven by real-time data, real-time dynamic interactive mapping between the physical entity and the virtual model is realized. The neural network model and genetic algorithm are used to evaluate and predict the running state of the equipment and provide the system adjustment strategy, so as to realize the whole climate, life and working condition of the staff to understand the running state of the equipment, and effectively ensure …

Cooperative Guidance For Multigroup Flight Vehicles Against Multiple Targets With Separated Impact Time, Guofei Li, Shituo Li, Yilun Huangfu, Yueyang Hua, Yunjie Wu, Zongyu Zuo

Journal of System Simulation

Abstract: To cope with cooperative guidance against multiple targets, a distributed cooperative guidance for multigroup flight vehicles to strike multiple targets with separated impact time is proposed. The collaborative variables for multigroup flight vehicles with separated impact time are given, and the guidance law in the line of sight (LOS) is proposed. The guidance laws on the normal and lateral directions of the LOS are proposed to make the LOS deflection angle rate and LOS the inclination angle rate converge rapidly, which ensures that each vehicle is able to strike the target. The finite-time convergence of the proposed guidance laws …

Automatic Multi-Objective Optimization Based On Dynamic Storage Location Allocation Strategy, Juan Chen, Wang Zheng, Qianqian Liu, Bin Lu

Journal of System Simulation

Abstract: Based on the dynamic storage allocation strategy, the two-stage optimization model is constructed with the whole warehouse as the main optimization body, in order to meet the safety and rationality of the storage allocation goals, and to meet the dispatching goals of the shortest operation time and the lowest energy consumption of each stacke. The upper and lower levels of the model are typical multi-objective optimization problems, and the ideal solution of the upper level model will be the initial condition of the lower level model. The multi-objective genetic algorithm is used to solve the ideal solution of the …

Soft Sensor Modeling Based On Adaptive Sparse Broad Learning System⋅, Kangping Du, Lin Sui, Weili Xiong

Journal of System Simulation

Abstract: To address the challenges posed by nonlinearity and the coupling of multiple features in complex industrial processes, resulting in increased model complexity and decreased performance, a soft sensor modeling method based on adaptive sparse broad learning system is proposed. Building upon the lateral enhancement transmission of features, the trace least absolute shrinkage and selection operator (LASSO) is further used to optimize the feature weights of the network, adaptively adjusting the penalty intensity based on the correlation between different variables to enhance the feature extraction capabilities of the model. The Dropout mechanism is introduced in the enhanced part, and the …

Enhanced Artificial Gorilla Algorithm For Mobile Robot Path Planning, Chen Ye, Peng Shao, Shaoping Zhang, Wenting Li, Tengming Zhou

Journal of System Simulation

Abstract: To address the issues of susceptibility to local optima and slow convergence in mobile robot path planning within complex terrain scenarios, an enhanced artificial gorilla troops optimizer with integration of quadratic interpolation and elite individual genetic strategies (QGGTO) is proposed. The algorithm integrates quadratic interpolation and elite individual genetic strategies to promote information exchange among candidate solutions, thereby accelerating convergence, while maintaining population diversity to avoid local optima. For complex terrains containing both regular and irregular obstacles, a cost function that comprehensively considers walking distance, safety, and turning angles is constructed to uniformly evaluate the path planning performance of …

Multi-Model Based Iterative Method For System-Of-Systems Architecture Design, Xuemeng Zhao, Tianzhu Ren, Zhemei Fang

Journal of System Simulation

Abstract: In order to solve the problems of difficulties in expressing dynamic characteristics and lack of decision analysis support in developing models of the department of defense architecture framework (DoDAF), an integrated iterative method for combat SoS architecture design is proposed. The DoDAF architecture model integrates and expresses combat-related information from multiple perspectives; the ExtendSim executable model simulates the emergence behavior and dynamic characteristics of combat SoS architecture in multiple scenarios; and the decision model quantitatively analyzes and selects architecture schemes by multi-objective decision rules. Ultimately, a SoS architecture integrated iterative design method of "view-simulate-decide-iterate" is formed. The design process …

A Drl⁃Based Approach For Distributed Equipment Nodes Selection, Ziyi Wang, Kai Zhang, Dianwei Qian, Yuzhen Liu

Journal of System Simulation

Abstract: Aiming at the problem of insufficient solution speed and poor generalization of traditional algorithms in large-scale scenarios, this paper intelligently solves the large-scale distributed equipment system preference problem based on deep reinforcement learning. According to the characteristics of distributed equipment system combat, using the complex network to its graph form modeling, and based on the attention mechanism to the equipment between the connecting edge relationship for the characterization, in order to build a distributed equipment system digital simulation environment. Simulation results show that compared with the genetic evolutionary algorithm, the obtained model has obvious advantages in terms of solution …

Research On Improving Design Efficiency Of Coaxial Magnetic Gear Based On Linear Model, Shuguang Zhao, Ce Chen, Xiaochang Xie, Fuping Li, Jin Han

Journal of System Simulation

Abstract: To address the issues of large model computation load and cumbersome magnetization direction setting during the simulation design of coaxial magnetic field modulation type magnetic gears, a simplified design method is proposed, which uses a linear model to replace the original conventional circular ring model. Based on the periodicity of the structure and magnetic field of each part of the magnetic gear, the modeling work is simplified and the computational load of the simulation analysis is reduced. The results show that compared with the circular ring structure, the number of magnetization coordinate system settings for the linear structure is …

Stratigraphic Evidence Of Backwater Morphodynamics And Lowland River Deltas In The Northern Hemisphere Of Mars, C.M. Hughes, J.B. Shaw, A.M. Fernandes, T.E. Swanson

Geosciences Faculty Publications and Presentations

Backwater morphodynamics describe feedbacks between hydraulics and sedimentation in fluvio-deltaic systems in the coastal backwater zone. On Earth, normalized channel belt width decreases approaching the coastline and drops sharply at the start of the backwater zone. This systematic decrease allows a backwater/belt-width window to be defined, one backwater length upstream from the coast with normalized widths from 2 to 6. We use the backwater/belt-width window to interpret backwater morphodynamics and estimate backwater length on Mars using narrowing channel belts at Aeolis Dorsa. We measure nine belts from martian delta deposits and compare normalized width to distance upstream from an ancient …

Linking Static And Dynamic Structures And Properties Of Materials With Computational And Mathematical Models, (Enoch) Sin Hang Ho

Theses and Dissertations

Terahertz (THz) spectroscopy is an effective technique to study and manipulate the structural dynamics of materials, due to its frequency range being very similar to the vibrational frequencies of collective atom motions in a host of materials. High-field and broadband THz radiation can be generated via optical rectification (OR) in nonlinear optical (NLO) crystals. The efficiency of OR response in an NLO crystal is determined by many factors, including molecular hyperpolarizability (β), 2nd order electric susceptibility (χ(2)), crystal structure, primary growth orientation, refractive index, absorption and phase matching condition. In this dissertation, I will focus on using computation methods and …

Fort Hays State University Tiger Weekly, June 20, 2025, University Relations

Tiger Weekly Newsletters

No abstract provided.

Readiness For The New Science Teks: A Needs Assessment, Roxanne Rodriguez

Masters Theses (Archived)

No abstract provided.