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Articles 62791 - 62820 of 291657

Full-Text Articles in Physical Sciences and Mathematics

Computational Framework Of Magnetized Mgo–Ni/Water-Based Stagnation Nanoflow Past An Elastic Stretching Surface: Application In Solar Energy Coatings, M, M. Bhatti, O. A. Bég, Sara Abdelsalam Jan 2022

Computational Framework Of Magnetized Mgo–Ni/Water-Based Stagnation Nanoflow Past An Elastic Stretching Surface: Application In Solar Energy Coatings, M, M. Bhatti, O. A. Bég, Sara Abdelsalam

Basic Science Engineering

In this article, motivated by novel nanofluid solar energy coating systems, a mathematical model of hybrid magnesium oxide (MgO) and nickel (Ni) nanofluid magnetohydrodynamic (MHD) stagnation point flow impinging on a porous elastic stretching surface in a porous medium is developed. The hybrid nanofluid is electrically conducted, and a magnetic Reynolds number is sufficiently large enough to invoke an induced magnetic field. A Darcy model is adopted for the isotropic, homogenous porous medium. The boundary conditions account for the impacts of the velocity slip and thermal slip. Heat generation (source)/absorption (sink) and also viscous dissipation effects are included. The mathematical …

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Identifying Challenges And Opportunities For Designing Social Media Nudges For Adolescents, Oluwatomisin Obajemu Jan 2022

Identifying Challenges And Opportunities For Designing Social Media Nudges For Adolescents, Oluwatomisin Obajemu

Electronic Theses and Dissertations, 2020-2023

With the prevalence of online risks encountered by youth online, strength-based approaches such as nudges have been recommended as a potential solution to subtly guide teens toward safer decisions. However, most nudging interventions to date have not been designed to cater to teens’ unique needs and online safety concerns. To address this gap, this study aimed to better understand adolescents’ perceptions and feedback on online safety nudges to inform the design of more effective online safety interventions. We conducted 12 semi-structured interviews and 3 focus group sessions with 21 teens (13 – 17 years old) to get their feedback on …

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"Reeling In" Juvenile Sportfish Through Coastal Habitat Restoration: Population, Community, And Trophic Responses In The Indian River Lagoon, Florida, Jennifer Loch Jan 2022

"Reeling In" Juvenile Sportfish Through Coastal Habitat Restoration: Population, Community, And Trophic Responses In The Indian River Lagoon, Florida, Jennifer Loch

Electronic Theses and Dissertations, 2020-2023

Coastal habitats provide crucial nursery habitat for predatory fishes, but they are in decline worldwide, impacting economically important fisheries. Habitat restoration can simultaneously mitigate the effects of habitat loss and benefit predators (e.g., sportfish), although this relationship is understudied. Here, the response of juvenile sportfish to oyster reef and living shoreline restoration is compared to controls in the Indian River Lagoon, Florida prior to and following restoration for up to three years through examination of community (diversity, assemblage), population (abundance), biometric (size, body condition), ontogenetic, and trophic (gut contents, stable isotopes) dynamics. Stable isotopes were used to quantify dietary history, …

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Authoring Tools For Augmented Reality Scenario Based Training Experiences, Andres Vargas Gonzalez Jan 2022

Authoring Tools For Augmented Reality Scenario Based Training Experiences, Andres Vargas Gonzalez

Electronic Theses and Dissertations, 2020-2023

Augmented Reality's (AR) scope and capabilities have grown considerably in the last few years. AR applications can be run across devices such as phones, wearables, and head-mounted displays (HMDs). The increasing research and commercial efforts in HMDs capabilities allow end users to map a 3D environment and interact with virtual objects that can respond to the physical aspects of the scene. Within this context, AR is an ideal format for in-situ training scenarios. However, building such AR scenarios requires proficiency in game engine development environments and programming expertise. These difficulties can make it challenging for domain experts to create training …

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Electronic And Optoelectronic Properties Of Two-Dimensional Heterostructures For Next-Generation Device Technologies, Jesse Thompson Jan 2022

Electronic And Optoelectronic Properties Of Two-Dimensional Heterostructures For Next-Generation Device Technologies, Jesse Thompson

Electronic Theses and Dissertations, 2020-2023

Since monolayer graphene was isolated in 2004, there has been significant interest in integrating layered materials into innovative device designs and hybrid materials to help solve pressing technological challenges. This is partially because they can typically be thinned to a two-dimensional (2D) form without suffering from roughness-induced scattering and can exhibit thickness-dependent variations in properties such as their energy band gap. This dissertation reports on investigations of electronic and optoelectronic device physics in 2D material heterostructures. The investigation of electronic device physics focuses on the interface between 2D molybdenum disulfide (MoS2) and gold (Au), which behaves as a resistive switching …

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Machine Learning In Fiber Optics, Xiaowen Hu Jan 2022

Machine Learning In Fiber Optics, Xiaowen Hu

Electronic Theses and Dissertations, 2020-2023

Recent burgeoning machine learning has revolutionized our ways of looking at the world. Being extraordinarily good at pattern recognition, machine learning has been widely applied to many fields to solve challenging problems. This dissertation demonstrates the applications of machine learning on scanning-free fiber-optic imaging systems (FOISs), and on the design of anti-resonant fibers. In the first part, we propose a semi-supervised learning framework called the adaptive inverse mapping (AIP) to stabilize the imaging performance through multimode fibers (MMFs). We show that if the state of the MMF is traced closely, the output images can be used as probes to correct …

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Computational And Experimental Studies Of Adsorption And Reactions On Molybdenum Nitride And Silica Covered Ruthenium Surfaces, Muhammad Sajid Jan 2022

Computational And Experimental Studies Of Adsorption And Reactions On Molybdenum Nitride And Silica Covered Ruthenium Surfaces, Muhammad Sajid

Electronic Theses and Dissertations, 2020-2023

Fundamental studies of material surfaces are of continued interest to the development and improvement of many modern technologies, e.g. catalysis, energy efficient electronics, and high-capacity batteries etc. This dissertation targets two distinct sets of molecule-surface interactions relevant to the continued development of structure-property correlations using tools from Density Functional Theory with added verification from ultrahigh vacuum surface-science experiments. These include Haber-Bosch interactions at molybdenum-nitride surfaces and separation-dependent interactions between simple aromatics and Ru(0001) used to model a metal contact of Organic Electronic Devices (OEDs). In the first study, we focus on computational modelling of nitrogen fixation reactions on Mo- and …

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Population Persistence And Disease Invasion In Heterogenous Networks, Poroshat Yazdanbakhshghahyazi Jan 2022

Population Persistence And Disease Invasion In Heterogenous Networks, Poroshat Yazdanbakhshghahyazi

Electronic Theses and Dissertations, 2020-2023

The problem of understanding how biological species and infectious diseases can persist and spread in heterogeneous networks has brought a wide attention, recently highlighted due to the COVID-19 pandemic. This dissertation investigates the connection between the structures of heterogeneous networks and population persistence/disease invasion. To do so, we propose a new index for network heterogeneity by employing the Laplacian matrix of population dispersal and its corresponding group inverse. The network growth rate and reproduction number can be evaluated using the network average and the network heterogeneity index as the first and second order approximation, respectively. We also illustrate the impact …

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Towards More Efficient Collaborative Distributed Data Analysis And Learning, Zixia Liu Jan 2022

Towards More Efficient Collaborative Distributed Data Analysis And Learning, Zixia Liu

Electronic Theses and Dissertations, 2020-2023

Modern information era gives rise to the persistent generation of large amounts of data with rapid speed and broad geographical distribution. Obtaining knowledge and understanding via analysis and learning from such data have invaluable worth. Features of such data analytical tasks commonly include: data can be large scale and geographically distributed; computing capability demand can be enormous; tasks can be time-critical; some data can be private; participants can have heterogeneous capabilities and non-IID data; and multiple simultaneously submitted data analytical tasks can be possible. These bring challenges to contemporary computing infrastructure and learning models. In view of this, we develop …

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Observation Of Anisotropic Properties In Topological Quantum Materials, Gyanendra Dhakal Jan 2022

Observation Of Anisotropic Properties In Topological Quantum Materials, Gyanendra Dhakal

Electronic Theses and Dissertations, 2020-2023

The discovery of the three-dimensional topological insulator (TI) has enormously impacted our understanding of quantum materials. These novel materials are characterized by the topology rather than some order parameters. The TIs are the materials that exhibit insulating properties in the bulk while possessing the metallic state on the surface. These surface states are protected by time-reversal symmetry; as a result, the electrons featuring surface states are spin-polarized. After the discovery of TIs, other topological semimetallic (TSM) states were discovered, which enhanced the understanding and widened the reach of topological materials. Discoveries of various topological phases such as Dirac, Weyl, nodal …

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Volume Bragg Gratings With Complex Phase Structures: A Three-Dimensional Foundation For Laser-Beam Engineering, Lam Mach Jan 2022

Volume Bragg Gratings With Complex Phase Structures: A Three-Dimensional Foundation For Laser-Beam Engineering, Lam Mach

Electronic Theses and Dissertations, 2020-2023

Bragg diffraction is a natural phenomenon that arises from the coherent interference of scattered waves in multilayer structures with a well-defined periodicity. In practice, the physical size of these multilayer structures varies depending on the intended application, from micrometer-thick dielectric mirrors with tens of layers to centimeter-long Bragg gratings with ten-thousands of layers. The scope of this work centers around a unique class of multilayer elements developed in bulk photo-thermo-refractive (PTR) glass – the volume Bragg grating (VBG). The content of this thesis places an emphasis on the volume nature of these Bragg devices, implying a three-dimensional structure whereupon arbitrary …

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Design Of A High-Power Terahertz Emitter Array Using A High-Temperature Superconductor, Ruqayyah Shouk Jan 2022

Design Of A High-Power Terahertz Emitter Array Using A High-Temperature Superconductor, Ruqayyah Shouk

Electronic Theses and Dissertations, 2020-2023

By applying a dc voltage V across the stack of intrinsic Josephson junctions naturally present in the high-temperature superconductor consisting of two parts bismuth, two parts strontium, one part calcium, two parts copper, and a bit more than eight parts oxygen, several groups have been able to obtain coherent THz emission at output powers in the µW range. In order to enhance the output power well into the mW range suitable for many applications, we have studied a compact design of a stand-alone mesa array with gold layers on the top and bottom of the superconductor. In this design, an …

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Surface Engineering For Controlled Growth And Deposition Of Nanomaterials - Assembly And Design At The Nano-Microscale, David Fox Jan 2022

Surface Engineering For Controlled Growth And Deposition Of Nanomaterials - Assembly And Design At The Nano-Microscale, David Fox

Electronic Theses and Dissertations, 2020-2023

Materials with nanoscale dimensions offer several important benefits over bulk materials (e.g. increased surface area, low-cost, deviation from bulk properties, etc.). Such materials are critical components for next-generation energy storage materials, optoelectronic devices, and catalyst systems. However, these materials are often processed in liquid media, and their diminutive structures are fragile in the presence of capillary forces. As such, preparing uniform and stable nanomaterial coatings is a significant challenge. Herein, we discuss an approach where the substrate itself is factored into the assembly and growth of these materials. First, nanoporous surfaces were utilized to achieve a uniform deposition of one-dimensional …

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Methodology Of Augmented Reality Chinese Language Articulatory Pronunciation Practice: Game And Study Design, Daria Sinyagovskaya Jan 2022

Methodology Of Augmented Reality Chinese Language Articulatory Pronunciation Practice: Game And Study Design, Daria Sinyagovskaya

Electronic Theses and Dissertations, 2020-2023

Learning a language can be hard. Learning a language that contains tones to convey meaning is even harder. This dissertation presents a novel methodology for creating a language practice using augmented reality that has never been used before. The design of a new app in AR and non-AR versions can evaluate the same practice methodology. This methodology was applied to new software and was examined in regard to the importance of this software. Although the study results are inconclusive, progress has been made in answering research questions on the effectiveness of AR versus non-AR and the reliability of peer assessment. …

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Terahertz Spintronics With Antiferromagnetic Insulators, Gyan Khatri Jan 2022

Terahertz Spintronics With Antiferromagnetic Insulators, Gyan Khatri

Electronic Theses and Dissertations, 2020-2023

The existence of the THz gap in the electromagnetic spectrum is not only preventing the advancement of several technologies but also hindering research and developmental activities due to a lack of research facilities operating in the gap region. There is a plethora of materials with dynamics lying in the THz gap region whose study could potentially lead to the development of new technologies for the generation, detection, and processing of THz signals. Antiferromagnets are gaining recent interest due to their high frequency dynamics lying in the THz region, and their potential uses as active elements in THz spintronics devices have …

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Raman Excitation Laser Effects On Peak Parameters And Peak Metamorphic Temperatures Of Primitive Carbonaceous Chondrites, Amy Lebleu-Debartola Jan 2022

Raman Excitation Laser Effects On Peak Parameters And Peak Metamorphic Temperatures Of Primitive Carbonaceous Chondrites, Amy Lebleu-Debartola

Electronic Theses and Dissertations, 2020-2023

MicroRaman (µRaman) spectroscopy is often regarded as a non-destructive technique, utilized to analyze limited materials, both terrestrial and extraterrestrial. Carbonaceous chondrite meteorites are of particular interest but they are dark (low albedo) materials, and thus absorb the majority of incident visible light. Raman excitation lasers can induce considerable localized heating, even when low laser powers are used. It has been previously suggested to utilize low power lasers of =0.4 mW to minimize damaging carbonaceous samples in several fields, including Meteoritics, Geology, Chemistry, and Paleontology. Peak Metamorphic Temperatures (PMT) experienced by the meteorite can be estimated from Raman fitting parameters related …

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Electrochemical Gelation Of Metal Chalcogenide Quantum Dots, Chathuranga Chinthana Hewa Rahinduwage Jan 2022

Electrochemical Gelation Of Metal Chalcogenide Quantum Dots, Chathuranga Chinthana Hewa Rahinduwage

Wayne State University Dissertations

Quantum dots (QDs) are attractive because of their unique size-dependent optical and electronic properties and high surface area. They are tested in research for diverse applications, including energy conversion, catalysis, and sensing. Assembling QDs into functional solid-state devices while preserving their attractive properties is a challenge. Methods currently under the research are not effective in directly fabricating QDs onto devices, making large area assemblies, maintaining the high surface area by forming 3D porous structures, and conducting electricity for applications such as sensing. QD gels are an example of QD assemblies that consist of a 3D porous interconnected QD network. They …

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Long Island Horseshoe Crab Network Annual Inventory Report, Cercom, Molloy University, John Tanacredi Ph.D., Kyle F. Maurelli Jan 2022

Long Island Horseshoe Crab Network Annual Inventory Report, Cercom, Molloy University, John Tanacredi Ph.D., Kyle F. Maurelli

CERCOM Reports

CERCOM monitors 115 beach locations from Brooklyn – Montauk during the optimal Limulus Polyphemus breeding season. These beach surveys take place for approximately 15 weeks, ranging from May - August. These beach locations are marked specifically using GPS coordinates, to assure the same location is visited each year. Students and volunteers are required to attend a HSC Survey training orientation led by CERCOM’s research assistant, Mr. Kyle Maurelli. Surveying is done around tide and moon cycles (New/Full Moon). Each site takes about 1-2 hours and data is recorded along an approximate 1 mile distance. Walking along the water’s edge the …

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Strategies For The Reduction Of Cybersecurity Breaches In Hospitals, Donovan M. A. Pottinger Jan 2022

Strategies For The Reduction Of Cybersecurity Breaches In Hospitals, Donovan M. A. Pottinger

Walden Dissertations and Doctoral Studies

AbstractRecent cyberattacks in hospitals show the urgency of the need to enhance secure information technology (IT) infrastructure. Hospitals are statistically more at cyber risk than all the multiple industries against ransomware, malware, hacking and internal threats. Guided by routine activity theory, the purpose of this exploratory multiple case study was to explore strategies utilized by hospitals' IT security managers to reduce cybersecurity breaches associated with sensitive data. The participants were nine IT security managers from hospitals in the eastern United States. Data were collected via semistructured interviews and supporting documentation from the consenting participants and hospitals' websites. Through thematic analysis, …

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Strategies To Secure A Voice Over Internet Protocol Telephone System, Sherese Bernard Jan 2022

Strategies To Secure A Voice Over Internet Protocol Telephone System, Sherese Bernard

Walden Dissertations and Doctoral Studies

Voice over internet protocol (VoIP) provides cost-effective phone service over a broadband internet connection rather than analog telephone services. While VoIP is a fast-growing technology, there are issues with intercepting and misusing transmissions, which are security concerns within telecommunication organizations and for customers. Grounded in the routine activity theory, the purpose of this multiple case study was to explore strategies information technology (IT) security managers used to secure VoIP telephone systems in telecommunication organizations. The participants consisted of nine IT security managers from three telecommunication organizations in New York who possessed the knowledge and expertise to secure a VoIP telephone …

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Enterprise Resource Planning Implementation Strategies In Small- And Medium-Sized Manufacturing Enterprises, Tatianna Gilliam Jan 2022

Enterprise Resource Planning Implementation Strategies In Small- And Medium-Sized Manufacturing Enterprises, Tatianna Gilliam

Walden Dissertations and Doctoral Studies

The difficulty SME leaders of manufacturing firms experience in the executing of enterprise resource planning (ERP) systems threatens the longevity of innovative change within firms seeking to adopt ERP systems. Grounded in the diffusion of innovation theory, the purpose of this multiple case study was to examine critical success factors used to successfully implement ERP systems. The participants were four ERP business leaders of small to medium size manufacturing firms based on the east and west coasts of the United States. Data were collected using semistructured online interviews and a review of company documents. Through thematic analysis, five themes were …

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Strategies For Developing Sustainable Supply Chain Links With Local Producers, Edwin Che Ngwa Jan 2022

Strategies For Developing Sustainable Supply Chain Links With Local Producers, Edwin Che Ngwa

Walden Dissertations and Doctoral Studies

Failure to sustain agriculture supply chain links with local producers may lead to supply chain disruptions affecting the flow of products and materials. Successful strategies are essential for agribusiness supply chain managers to maintain profitability. Grounded in the value-based supply chain model, the purpose of this qualitative multiple case study was to explore strategies agribusiness managers used to develop sustainable supply chain links with local producers to maintain profitability. Semistructured online interviews were conducted with six Cameroon agribusiness managers who developed sustainable supply chain links with local producers for more than 5 years. Data analysis of the interviews and administrative …

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Successful Information Technology Project Process Management Best Practices, Jude Oderaa Orazulike Jan 2022

Successful Information Technology Project Process Management Best Practices, Jude Oderaa Orazulike

Walden Dissertations and Doctoral Studies

Globally, most information technology projects (ITPs) are reported as unsuccessful. Poor project management practices have consistently been identified as the leading cause of ITP failures. However, ITP practitioners manage project processes in diverse ways without clear guiding principles in terms of what does or does not work in practice for success. Process management practices in projects were explored in this grounded theory qualitative study from a systems theory perspective. The purpose was to understand from project practitioners' experiences what guiding principles potentially influenced ITPs to success. These experiences were then analyzed to develop a theory describing how to best use …

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Impact Of Internal Control, Cybersecurity Risk, And Competitive Advantage On Retail Cybersecurity Budget, Samuel William Pfanstiel Jan 2022

Impact Of Internal Control, Cybersecurity Risk, And Competitive Advantage On Retail Cybersecurity Budget, Samuel William Pfanstiel

Walden Dissertations and Doctoral Studies

Retail organizations are driven to improve security posture for many reasons, including meeting financial regulation requirements, mitigating threats of data breach, and differentiating themselves within markets affected by customer perception. The problem was that little was known about how these drivers of internal control, cybersecurity risk, and competitive advantage impact retail cybersecurity budgets within the retail sector. The purpose of this quantitative nonexperimental correlational study was to describe the relationship between cybersecurity budget and drivers of internal control, cybersecurity risk, and competitive advantage among U.S.-based retail merchant organizations. Real options theory provided a foundation for explaining this decision-making process. Data …

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Infrastructure As Code Strategies And Benefits In Cloud Computing, Jeffrey Chijioke-Uche Jan 2022

Infrastructure As Code Strategies And Benefits In Cloud Computing, Jeffrey Chijioke-Uche

Walden Dissertations and Doctoral Studies

Hybrid and multicloud infrastructure implementation without automation and versioning strategy can negatively impact organizations’ productivity. Organization leaders must ensure that infrastructures are implemented using the infrastructure as code (IaC) strategy because implementation solutions, including automated and DevOps procedures, provide assets for repeatable infrastructure implementation use cases. Grounded in the disruptive innovation theory, the purpose of this qualitative pragmatic inquiry study was to explore strategies solution architects use to implement IaC architecture using repeatable assets with DevOps procedures in cloud computing. The participants were seven solution architects in the information technology (IT) industry within the United States who have successfully implemented …

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Strategies For Catalyzing Supply Chain Innovation In Midsized Manufacturing Firms, Matthew J. Szukalowski Iii Jan 2022

Strategies For Catalyzing Supply Chain Innovation In Midsized Manufacturing Firms, Matthew J. Szukalowski Iii

Walden Dissertations and Doctoral Studies

Supply chain inflexibility results in reduced efficiency and profitability. Without supply chain flexibility, supply chain managers in manufacturing firms risk the loss of competitive advantage due to reduced efficiency and profitability. Grounded in business process engineering conceptual framework, the purpose of this qualitative multiple case study was to explore strategies supply chain leaders in manufacturing organizations use to achieve supply chain flexibility. The participants were five supply chain leaders in the manufacturing industry in the midwestern United States and successfully implemented innovative solutions to achieve supply chain flexibility. Data were collected using semistructured interviews and a review of company documents …

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Digital Strategies To Improve The Performance Of Pharmaceutical Supply Chains, Manish Shashi Jan 2022

Digital Strategies To Improve The Performance Of Pharmaceutical Supply Chains, Manish Shashi

Walden Dissertations and Doctoral Studies

Some supply chain managers at pharmaceutical companies lack strategies to digitalize integrated supply chain systems impacting their profitability. Digitalized supply chain management in a pharmaceutical company can help reduce operation costs, improve assets, enhance shareholders’ value, positively respond to customer demand, and generate profits. Guided by the theory of constraints, the purpose of this qualitative multiple case study was to explore strategies some pharmaceutical managers use to digitalize integrated supply chain systems to increase their profitability. The participants were five managers from four pharmaceutical companies in New Jersey with strategies to digitalize their integrated supply chain systems. Data collection included …

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Tolle Lege Works Published In 2022, Mcquade Library Jan 2022

Tolle Lege Works Published In 2022, Mcquade Library

Bibliographies

Compiled Tolle Lege bibliography of works published by members of the Merrimack College Community in 2022. Works include journal articles, books, book chapters, conference presentations and posters, and more.

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Examining Trends And Experiences Of The Last Four Years Of Socially Engineered Ransomware Attacks, William Seymour Jan 2022

Examining Trends And Experiences Of The Last Four Years Of Socially Engineered Ransomware Attacks, William Seymour

Cybersecurity Undergraduate Research Showcase

This study examines and reports the trends of social engineering-based ransomware attacks over the past four years from three major technology corporations. The focus of the reports was on major threat actors and their attacks against the corporations and their clients. The data were organized chronologically by year, and prevalent or abnormal findings were shared in this report. It was found that social engineering attacks were tremendously effective. Many ransomware attacks stemmed from Phishing. Social engineering approaches allowed attackers to conduct breaches using ransomware applications like GandCrab and Ryuk. Humans are incredibly susceptible and fall for social engineering tactics- primarily …

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Security Issues With Network Connected Scada Systems, Chad Holm Jan 2022

Security Issues With Network Connected Scada Systems, Chad Holm

Cybersecurity Undergraduate Research Showcase

The use of Supervisory Control and Data Acquisition (SCADA) systems has become common place and are being used in several different industries. These have evolved as the technology has progressed. The use of Internet of Things (IOT) devices makes for less human intervention to run daily operations in these industries. This can also allow hackers to gain access to these devices due to security holes that are overlooked. There have several different ways that have been exploited on SCADA networks and the goal is to recognize and secure them so hackers cannot gain access to them.

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