Digital Commons Network^™

Practical Fixture Design For Passive Intermodulation Tests For Flexible Metallic Contacts, Shengxuan Xia, Yuchu He, Yansheng Wang, Hanfeng Wang, George Mankaruse, Danny Chan, Haicheng Zhou, Warren Lee, Nicholas Mcdonnell, Chulsoon Hwang

Electrical and Computer Engineering Faculty Research & Creative Works

Passive intermodulation (PIM) commonly exists in non-ideal metallic contacts. Since PIM typically represents an extremely low level of nonlinearity, it has not drawn enough attention over the years except for extremely high-power applications such as base stations. However, in recent years, the study on PIM has become essential in universally used consumer electronics design because of the higher requirement on the radio frequency (RF) sensitivity of wireless communications. The metal contacts caused PIM can create the sideband spectrum to interfere with the receiving band in the frequency divide duplex (FDD) mode. Therefore, the study on PIM for the frequently used …

3d Printed Multilayer Microwave Absorber, Wei Zhang, Rui Mi, Victor Khilkevich

Electrical and Computer Engineering Faculty Research & Creative Works

This paper explores the possibility to create 3D printed multilayer electromagnetic absorbers. The proposed design is similar to the thin-film filters used in optics and consists of interleaving high and low permittivity layers. Based on transmission line theory, the multilayer absorber can be designed in a circuit simulator. Analytical equations, circuit simulations, and measurements are used to analyze and validate the designed absorber. Multilayer absorbers based on 3D printed material can be an inexpensive option for engineering usage with great design flexibility and fast fabrication.

A New Discontinuous Conduction Mode In A Transformer Coupled High Gain Dc-Dc Converter, Kartikeya J.P. Veeramraju, Jacob Eisen, Joshua L. Rovey, Jonathan W. Kimball

Electrical and Computer Engineering Faculty Research & Creative Works

Electrospray space propulsion thrusters often employ transformer coupled high gain dc-dc converters. These thrusters have a unique load resistance profile that can vary dramatically during operation. Transformer coupled high gain dc-dc converters working in very low power modes can enter a unique discontinuous conduction mode (DCM) caused by a coupling effect between the boost and magnetization inductors in the converter. The transformer magnetization current prevents the boost inductors from discharging properly, which causes premature loss of boost action and higher than expected boost inductor voltages. This mechanism generates abnormally high voltages on the converter's output side, leading to converter and …

Two-Level Targeter Convergence Study For Collinear Libration Point Spacecraft Formations, Donna Jennings, Henry J. Pernicka

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Spacecraft formation flying has attracted an increasing amount attention over the past several decades including a growing interest in relative motion at the collinear lib ration points. This current work builds on previous efforts by further developing and characterizing a two-level targeting (TLT) algorithm used to determine relative motion at lib ration points by performing a convergence study. A parametric study was conducted to identify the sensitivity of the algorithm to a variety of inputs and constraints. The parametric study revealed that the two-level targeting algorithm convergence properties significantly improve when using a higher order initialization estimate. The size of …

Using Internet Reciprocal Teaching To Develop Second Graders' Online Text Evaluation Skills, Annika Buell

Dissertations and Theses @ UNI

This study was designed to explore the relationship between Internet Reciprocal Teaching (IRT) and young students’ online text evaluation skills. It built upon previous research that identified four main online reading comprehension skills: locating, evaluating, synthesizing, and communicating information that are similar yet more complex than offline reading comprehension skills. In the majority of previous research, participants were in fifth grade or above. This study aimed to observe the processes younger students go through while reading online text. Participants were second grade students in a Midwestern suburban elementary school.

Qualitative methods were used to collect data while students participated in …

Use Of Technology And Its Impact On Higher Order Thinking In The Science Classroom, Mauree Angelina Haage

Dissertations and Theses @ UNI

This study focuses on examining the impact of technology on higher order thinking in the science classroom by first examining the impact of a teacher’s knowledge of Bloom’s Revised Taxonomy on the integration of higher order thinking activities and then by examining what levels of higher order thinking exist when technology was utilized. Previous research has found correlations between the levels of Bloom’s Taxonomy exhibited when using technology, particularly probeware, simulations/virtual labs, and special software like LoggerPro. In addition, previous research has shown a trend of teachers inaccurately categorizing their lessons and activities as having a higher order thinking level …

The Impacts Of Adolescents' Leisure Activity Types On Psychological Well-Being, Academic Self-Efficacy, Self Esteem, And Stress, Dongyub Back

Dissertations and Theses @ UNI

Korean teenager deviance, school violence, and school dropout caused by academic stress are serious social issues within the country. High levels of student stress are likely to bring about depression and suicide resulting in a significant effect on their psychological well-being and life satisfaction. It is of particular concern for middle school students experiencing rapid physical and psychological developmental changes without proper support. Forty-five percent of Korean students’ indicated stress in their life and 27% experienced depression (Statistics Korea, 2019). Also, Korean middle school students (27.3%) have suicide impulse (Youm & Kim, 2019). These youth development issues are considered social …

How Do We Use Creative And Personal Memories For Creative Communication?, Tyler Robert Montgomery

Dissertations and Theses @ UNI

Inspired by the author’s memories, KeyBoard Memories and You have the Right to Forget are two short stage plays exploring topics of identity, time, and justice. This thesis uses personal and creative memories to develop stories in the form of scripts. The thesis begins with an example of creative writing inspired by the author’s personal and creative memories and describes the purpose of the project before moving into a review of literature that explains what memories are, how they work, and the different types of memories. Then the method section describes the methods of journaling and scripting writing, and then …

Doing Corpus Pragmatics: Variations In Speech Acts Performed In Conversations Occurring Naturally In Academic Contexts, Jacob Philip Rigal

Dissertations and Theses @ UNI

No abstract provided.

Effects Of Perceived Reach On Ratings Of Media Bias, Quality, And Agreement, Matthew Sedlacek

Dissertations and Theses @ UNI

The hostile media effect refers to individuals’ tendencies to perceive seemingly neutral news coverage as biased against their stance (Vallone et al., 1985). Research has shown this effect in partisan politics, with liberals and conservatives perceiving bias in information presented from the opposing side. The current study examined the effects of liberal or conservative and small or large audience news source manipulations on liberals’ and conservatives’ perceptions of media bias and the relationship between partisan identity and perceptions of bias. Three hundred and sixty participants read a news article presented with either a Fox News, CNN, PatriotNewsDaily, or The Progressive …

Educational Experiences Of First Generation Black African Students With And Without Dis/Abilities, Shehreen Iqtadar

Dissertations and Theses @ UNI

Several studies have focused on the disproportionate representation of students from historically multiply marginalized communities in special education (Artiles, 2011, 2013; Artiles et al., 2005; Brayboy et al., 2007; Cavendish et al., 2018; Cooc & Kiru, 2018; Dunn, 1968; Hosp & Reschly, 2004; O’Connor & Fernandez, 2006; Voulgarides et al., 2017). Only recently, researchers have begun to explore the connections between immigrant and refugee students and special education (Migliarini, 2017; Song, 2018; Qing, 2018). Missing in this literature are the critical accounts of students and (a) their perspectives about the nature of dis/ability and their placement within special education and …

Training For Challenging Behaviors In The School Setting, Kenzie Heusinkvelt

Dissertations and Theses @ UNI

School personnel are asked to plan for, implement, and evaluate Behavior Intervention Plans (BIPs) in the school setting; however, not all school personnel have been properly trained to do so. There is limited research to date that demonstrates how different school personnel are trained in planning, implementing, and evaluating BIPs. The current study involves school personnel which include school psychologists, school social workers, special education consultants, and special education teachers. These school personnel were asked to indicate how adequate they believed their educational training was in providing a good understanding of various behavior topics and how well their educational training …

Lexile Levels And Their Value To Public School Teachers, Kristin Schumacher

Dissertations and Theses @ UNI

This thesis examines how teachers perceive Lexile level and its value, and whether or not their beliefs inform their practice. To address questions regarding teachers’ beliefs about Lexile level, I designed and implemented an online survey for public school teachers. My research shows that teachers have a favorable view of Lexile level, that they believe both students and parents should be informed of students’ Lexile level, that books should be labeled with Lexile level, and that asking students to read within their Lexile level range is a good practice. This survey research reveals the need to further interrogate whether or …

Frank Capra's America: The Fall Of Political Ambiguity, 1930-1950, Lydia Lennice Pakala

Dissertations and Theses @ UNI

As the United States sank lower into an economic depression, Hollywood sought to turn bread lines into lines for the box office. While other entertainment outlets faltered, film, with its low cost tickets and ability to help patrons escape, remained prominent. Hollywood started to produce films with profit in mind and in the thick of this environment was Frank Capra, a man destined to become one of the most popular film directors of the 1930s and 1940s. Capra made a conscious effort to choose contemporary stories and as a result they are a glimpse not only into the history of …

Psychopathy And Emotion Regulation: The Mediating Role Of Motives And Goals, Morning S. Baker

Dissertations and Theses @ UNI

The purpose of this study was to examine the relation between psychopathy and emotion regulation as serially mediated by emotional motives and goals in an all-male sample. Six serial mediation models were proposed, three for each motive-type (i.e., hedonistic, instrumental), and two for each emotion (i.e., anger, fear, joy). Eight-hundred and seventy-eight participants were recruited via Amazon’s Mechanical Turk (MTurk). Results indicate that male MTurk workers with greater levels of psychopathy have poorer emotion regulation, emotion goals for experiencing anger and fear, hedonistic and instrumental motives for experiencing anger and fear, emotion goals for not experiencing joy, and hedonistic and …

Leading Early Childhood Education In Iowa Schools, Alaina T. Daters

Dissertations and Theses @ UNI

Over the last 15 years, Iowa’s Statewide Voluntary Preschool Programs (SWVPP) have undergone significant growth. By the end of the 2021-2022 school year, 323 out of 327 (99%) of Iowa public school districts offered preschool (Iowa Department of Education, 2022c). As a result, well over 450 Iowa administrators are potentially responsible for leading their district’s preschool program.

The purpose of this mixed methods research study was to gain an understanding of the experiences, knowledge, and pedagogical needs of licensed Iowa administrators that are responsible for their district’s SWVPP. Data was collected through a survey and analyzed using descriptive statistical analysis …

Monetization For Content Generation And User Engagement On Social Media Platforms: Evidence From Paid Q&A, Jonathan Hua Ye, Cecil Eng Huang Chua

Business and Information Technology Faculty Research & Creative Works

Social media platforms want to increase their valuation in terms of total content quantity and user engagement. Monetization is often used to induce user content generation. However, research documents that while monetization increases the quantity of specific kinds of content, it does not necessarily increase the total content quantity or user engagement (i.e., platform value). Furthermore, the impact of monetization may depend on the social status of content creators. This article investigates paid question and answer (paid Q&A). Based on expectancy theory and relevant research, this article hypothesizes the effects of introducing paid Q&A on both total content quantity and …

The Impact Of Perceived Manipulation, Motives, And Ethicality In Cause-Related Marketing: A Crm+ Model, Nathan W. Twyman, Sarah M. Stanley, Cassandra C. Elrod, Tamara M. Masters

Business and Information Technology Faculty Research & Creative Works

We Developed a CRM+ Model using Experimentation and Structural Equation Modeling Analysis. CRM+ Demonstrates Previously Unexplored Interrelationships among Consumer-Perceived Manipulation, Brand Motives, Perceived Ethicality of the Cause-Related Marketing, and Brand Attitude. CRM+ Reveals that Perceived Ethicality of the CRM Has a Significant Positive Effect on Brand Attitude, Though It is Not as Pronounced as the Effect of Perceived Altruistic Motives. Egoistic Motives Decrease Ethicality Perceptions But Has No Direct Effect on Brand Attitude. Altruistic Motive Perceptions Diminish Egoistic Motive Perceptions. CRM+ Suggests Marketing Managers Should Prioritize Emphasizing Altruistic Motives and Ethicality of the Partnership over Downplaying Egoistic Motives.

Information Systems Analysis And Design: Past Revolutions, Present Challenges, And Future Research Directions, Keng Siau, Carson Woo, Veda C. Storey, Roger H.L. Chiang, Cecil Eng Huang Chua, Jon W. Beard

Business and Information Technology Faculty Research & Creative Works

Systems Analysis and Design (SAND) is Undoubtedly a Pillar in the Field of Information Systems (IS). Some Researchers Have Even Claimed that SAND is the Field that Defines the Information Systems Discipline and is the Core of Information Systems. the Past Decades Have Seen the Development of Structured SAND Methodologies and Object-Oriented Methodologies. in the Early 1990s, Key Players in the Field Collaborated to Develop the Unified Modeling Language and the Unified Process. Agile Approaches Followed, as Did Other Dynamic Methods. These Approaches Remain Heavily Employed in the Development of Contemporary Information Systems. at the Same Time, New Approaches Such …

Noise Resilient Learning For Attack Detection In Smart Grid Pmu Infrastructure, Prithwiraj Roy, Shameek Bhattacharjee, Sahar Abedzadeh, Sajal K. Das

Computer Science Faculty Research & Creative Works

Falsified data from compromised Phasor Measurement Units (PMUs) in a smart grid induce Energy Management Systems (EMS) to have an inaccurate estimation of the state of the grid, disrupting various operations of the power grid. Moreover, the PMUs deployed at the distribution layer of a smart grid show dynamic fluctuations in their data streams, which make it extremely challenging to design effective learning frameworks for anomaly-based attack detection. In this paper, we propose a noise resilient learning framework for anomaly-based attack detection specifically for distribution layer PMU infrastructure, that show real time indicators of data falsifications attacks while offsetting the …

Cansafe: An Mtd Based Approach For Providing Resiliency Against Dos Attack Within In-Vehicle Networks, Ayan Roy, Sanjay Kumar Madria

Computer Science Faculty Research & Creative Works

Trending towards autonomous transportation systems, modern vehicles are equipped with hundreds of sensors and actuators that increase the intelligence of the vehicles with a higher level of autonomy, as well as facilitate increased communication with entities outside the in-vehicle network. However, increase in a contact point with the outside world has exposed the controller area network (CAN) of a vehicle to remote security vulnerabilities. In particular, an attacker can inject fake high priority messages within the CAN through the contact points, while preventing legitimate messages from controlling the CAN (Denial-of-Service (DoS) attack). In this paper, we propose a Moving Target …

Rssafe: Personalized Driver Behavior Prediction For Safe Driving, Bhumika, Debasis Das, Sajal K. Das

Computer Science Faculty Research & Creative Works

While the increased demand for taxi services like Uber, Lyft, Hailo, Ola, Grab, Cabify etc. provides livelihood to many drivers, the desire to raise income forces the drivers to work very hard without rest. However, continuous journeys not only affect their health, but also lead to abnormal driving behavior such as rash driving, swerving, sideslipping, sudden brakes, or weaving, leading to accidents in the worst cases. Motivated by the severity of rising accidents and health issues among drivers, this paper proposes a recommendation system, called RsSafe, for the safety of drivers. Aiming to improve the driving quality and the driver's …

Toward Feature-Preserving Vector Field Compression, Xin Liang, Sheng Di, Franck Cappello, Mukund Raj, Chunhui Liu, Kenji Ono, Zizhong Chen, Tom Peterka, Hanqi Guo

Computer Science Faculty Research & Creative Works

The objective of this work is to develop error-bounded lossy compression methods to preserve topological features in 2D and 3D vector fields. Specifically, we explore the preservation of critical points in piecewise linear and bilinear vector fields. We define the preservation of critical points as, without any false positive, false negative, or false type in the decompressed data, (1) keeping each critical point in its original cell and (2) retaining the type of each critical point (e.g., saddle and attracting node). The key to our method is to adapt a vertex-wise error bound for each grid point and to compress …

Delivery With Uavs: A Simulated Dataset Via Ats, Giulio Rigoni, Cristina M. Pinotti, Bhumika, Debasis Das, Sajal K. Das

Computer Science Faculty Research & Creative Works

We consider a delivery food service operated by Unmanned Aerial Vehicles (UAVs). Due to the absence of a dataset on UAVs deliveries in the literature, and since it is not possible to perform real tests, we create a dataset using an open-Air Traffic Simulator (ATS). Precisely, we converted a set of food deliveries operated by wheeled vehicles, proposed in the literature [1], into a set of simulated UAVs deliveries. For each delivery, we ran a UAV flight from the source to the destination. The results showed that, as expected, the UAV's course is shorter than the vehicle trajectory on the …

Active Learning Augmented Folded Gaussian Model For Anomaly Detection In Smart Transportation, Venkata Praveen Kumar Madhavarapu, Prithwiraj Roy, Shameek Bhattacharjee, Sajal K. Das

Computer Science Faculty Research & Creative Works

Smart transportation networks have become instrumental in smart city applications with the potential to enhance road safety, improve the traffic management system and driving experience. A Traffic Message Channel (TMC) is an IoT device that records the data collected from the vehicles and forwards it to the Roadside Units (RSUs). This data is further processed and shared with the vehicles to inquire the fastest route and incidents that can cause significant delays. The failure of the TMC sensors can have adverse effects on the transportation network. In this paper, we propose a Gaussian distribution-based trust scoring model to identify anomalous …

Improving Age Of Information With Interference Problem In Long-Range Wide Area Networks, Preti Kumari, Hari Prabhat Gupta, Tanima Dutta, Sajal K. Das

Computer Science Faculty Research & Creative Works

Low Power Wide Area Networks (LPWAN) offer a promising wireless communications technology for Internet of Things (IoT) applications. Among various existing LPWAN technologies, Long-Range WAN (LoRaWAN) consumes minimal power and provides virtual channels for communication through spreading factors. However, LoRaWAN suffers from the interference problem among nodes connected to a gateway that uses the same spreading factor. Such interference increases data communication time, thus reducing data freshness and suitability of LoRaWAN for delay-sensitive applications. To minimize the interference problem, an optimal allocation of the spreading factor is requisite for determining the time duration of data transmission. This paper proposes a …

Mobility Management In Industrial Iot Environments, Marco Pettorali, Francesca Righetti, Carlo Vallati, Sajal K. Das, Giuseppe Anastasi

Computer Science Faculty Research & Creative Works

The Internet Engineering Task Force (IETF) has defined the 6TiSCH architecture to enable the Industrial Inter-net of Things (IIoT). Unfortunately, 6TiSCH does not provide mechanisms to manage node mobility, while many industrial applications involve mobile devices (e.g., mobile robots or wearable devices carried by workers). In this paper, we consider the Synchronized Single-hop Multiple Gateway framework to manage mobility in 6TiSCH networks. For this framework, we address the problem of positioning Border Routers in a deployment area, which is similar to the "Art Gallery"problem, proposing an efficient deployment policy for Border Routers based on geometrical rules. Moreover, we define a …

Mdz: An Efficient Error-Bounded Lossy Compressor For Molecular Dynamics, Kai Zhao, Sheng Di, Danny Perez, Xin Liang, Zizhong Chen, Franck Cappello

Computer Science Faculty Research & Creative Works

Molecular dynamics (MD) has been widely used in today's scientific research across multiple domains including materials science, biochemistry, biophysics, and structural biology. MD simulations can produce extremely large amounts of data in that each simulation could involve a large number of atoms (up to trillions) for a large number of timesteps (up to hundreds of millions). In this paper, we perform an in-depth analysis of a number of MD simulation datasets and then develop an efficient error-bounded lossy compressor that can significantly improve the compression ratios. The contributions are fourfold. (1) We characterize a number of MD datasets and summarize …

Spade: Multi-Stage Spam Account Detection For Online Social Networks, Federico Concone, Giuseppe Lo Re, Marco Morana, Sajal K. Das

Computer Science Faculty Research & Creative Works

In recent years, Online Social Networks (OSNs) have radically changed the way people communicate. The most widely used platforms, such as Facebook, Youtube, and Instagram, claim more than one billion monthly active users each. Beyond these, news-oriented micro-blogging services, e.g., Twitter, are daily accessed by more than 120 million users sharing contents from all over the world. Unfortunately, legitimate users of the OSNs are mixed with malicious ones, which are interested in spreading unwanted, misleading, harmful, or discriminatory content. Spam detection in OSNs is generally approached by considering the characteristics of the account under analysis, its connection with the rest …

Locality-Aware Qubit Routing For The Grid Architecture, Avah Banerjee, Xin Liang, R. Tohid

Computer Science Faculty Research & Creative Works

Due to the short decohorence time of qubits available in the NISQ-era, it is essential to pack (minimize the size and or the depth of) a logical quantum circuit as efficiently as possible given a sparsely coupled physical architecture. In this work we introduce a locality-aware qubit routing algorithm based on a graph theoretic framework. Our algorithm is designed for the grid and certain 'grid-like' architectures. We experimentally show the competitiveness of algorithm by comparing it against the approximate token swapping algorithm, which is used as a primitive in many state-of-the-art quantum trans pilers. Our algorithm produces circuits of comparable …