Blockchain for global vaccinations efforts: State of the art, challenges, and future directions

The emergence of the coronavirus disease 2019 (COVID-19) global crisis negatively affected all aspects of human life. One of the most important methods used worldwide to survive this global crisis is the vaccination process to circumvent the proliferation of this pandemic. Many restrictions were alleviated in many countries such as access to public facilities and events. There is a huge amount of data about vaccination campaigns that are collected and maintained worldwide. Although the vaccination data can be analyzed to find out how the alleviation of restrictions can be applied if the data management process requires preserving key aspects like trust, transparency, and availability for easy and reliable access to such data. In this regard, blockchain technology is an excellent choice for meeting the requirements and providing a secure trusted framework for global verification. In this article, the related literature on blockchain technology is surveyed and summarized for all systems that embody solutions. The pros and cons of each solution are presented and provide a comparative summary. Furthermore, a detailed analysis is given to present the current problems and provide a promising mechanism to verify the vaccinated persons anywhere in the world, in a secure manner while retaining individual privacy

A novel method of overvoltage suppression due to de-energization of shunt reactor in high voltage system

Substations usually employ shunt reactors to reduce the reactive power of systems. Due to current chopping when the shunt reactor is shut off, a high frequency and amplitude overvoltage is generated. This study was aimed at eliminating switching-related overvoltages in shunt reactors so as to maintain the equipment, prevent insulation failure, and avoid reignition. Therefore, the circuit was modified according to the suggested mitigation strategy to verify that transient overvoltages are suppressed by the circuit breaker and shunt reactor. With a view to evaluate the existing chopping caused by the switching of reactor bank, the alternative transients program (ATP-Draw) model was used to simulate the transients resulting from switching a shunt reactor. This work has been put into practice for various current chopping values. The collected results of the simulation showed that the proposed model was significantly highlighted for the suppression of overvoltages, with the voltage across the circuit breaker being reduced from 679 KV to 478 KV at a current chopping value of 5 A and from 351 KV to 152 KV across the shunt reactor

Optimization of Vehicle to Grid System in a Power System With Unit Commitment

This thesis provides a comprehensive overview and analysis of the benefits of using plug-in electric vehicles (PEVs) in solving the unit commitment problem. PEVs are becoming more attractive and a rapid replacement of conventional fuel vehicles due to their environmental-friendly operation. Through collective control by an aggregator, PEVs batteries can also provide ancillary services such as load leveling and frequency regulation to improve the quality of power supplied in the power grid and reduce the cost of power generation. This study presents the modeling, simulation, and analysis of a vehicle-to-grid (V2G) system connected to a smart power grid. The model considers different penetration levels of PEVs in a system and investigates the economic and technical effects of using PEVs to support the grid. The model is tested using an IEEE 24 bus network to verify the effects that PEVs penetration has on generation cost in power systems. A comparison has been made between a system without V2G and a system with V2G to produce justification for the role that V2G can play in solving the unit commitment problem. The results of this study show that the optimal scheduling of PEVs was effective in flattening the load profile through valley filling and peak load reduction

Ein neuartiges autonomes Echtzeit-Lastüberwachungs- und -steuerungssystem in Mikronetzen auf der Grundlage von Fuzzy-Logik-Steuerung und drahtloser LoRa-Kommunikation

Die dezentralen Mikronetze auf der Grundlage erneuerbarer Energiequellen (EE) bieten eine Lösung für den massiven Strommangel in den afrikanischen Ländern südlich der Sahara (SSA), insbesondere in abgelegenen Regionen, die nicht an die nationalen Stromnetze angeschlossen sind. Die auf erneuerbaren Energien basierenden Microgrids leiden jedoch unter Zuverlässigkeitsproblemen und häufigen Stromausfällen, die meist auf die Instabilität der Microgrids zurückzuführen sind. Dies resultiert aus der intermittierenden Natur der genutzten erneuerbaren Energiequellen. Das Fehlen einer angemessenen Lastüberwachung und -steuerung führt zu einem Verlust an Zuverlässigkeit und zu häufigen Stromausfällen. Um dieses Problem zu lösen, müssen die Mikronetze an dezentralen Standorten durch kosteneffiziente, hochpräzise und reaktionsfähige Systeme in Echtzeit überwacht werden, um schnell auf Ungleichgewichte zwischen Erzeugung und Verbrauch reagieren zu können. Fortschritte bei drahtlosen Sensornetzwerken, insbesondere Long-Range Wide Area Networks (LoRaWAN), werden genutzt, um ein kostengünstiges und bidirektionales drahtloses Sensornetzwerk zu entwickeln. In dieser Forschungsarbeit wird ein neuartiges sensorisches Echtzeit-Lastüberwachungs- und -steuerungssystem für Mikronetze vorgeschlagen. Das System basiert auf der Fuzzy-Logic-Controller-Technik (FLC) und der drahtlosen Long-Range-Kommunikationstechnologie (LoRa). Es verwaltet Ungleichgewichte zwischen Stromerzeugung und Energiebedarf, indem es auf der Grundlage der momentanen PV-Erzeugung und des Ladezustands des Batteriespeichersystems eine Belastungsgrenze für ein Mikronetz festlegt. Das vorgeschlagene System besteht aus einem drahtlosen, wartungsarmen Netzwerk verteilter Energiesensormodule zur Überwachung und Steuerung der Last auf der Nachfrageseite.The distributed microgrids based on Renewable Energy Sources (RES) offer a solution to the massive electricity shortage in Sub-Saharan Africa (SSA), especially in remote regions that are not connected to national grids. Nevertheless, RES-based microgrids suffer some reliability issues and experience frequent blackouts mainly due to microgrid instability. This is due to the intermittent nature of RES. Lack of proper load monitoring and control leads to loss of reliability and frequent power outages. To address this problem, the microgrids must be real-time monitored at distributed locations by cost-effective, high-accuracy, responsive systems to respond quickly to generation-consumption imbalances. Advancements in wireless sensor networks, particularly Long-Range Wide Area Networks (LoRaWAN), are leveraged to design an affordable and bidirectional wireless sensory network. This research work proposes a novel real-time load monitoring and control sensor system in microgrids. The system is based on Fuzzy Logic Controller (FLC) technique and Long-Range (LoRa) wireless communication technology. It manages imbalances between power generation and energy demand by setting a loading limit to a microgrid, based on the instant PV generation and State of Charge (SoC) of the battery energy storage system. The proposed system comprises a wireless low-power, a low-maintenance network of distributed power sensory modules for demand-side load monitoring and management. This study developed the prototypes of the system, and deployed it in a solar PV microgrid, in Silale village in Dodoma, Tanzania. The findings after the implementation of the developed system in the microgrid show that it is evidently possible to use a FLC-based traffic light for the load control to ensure a proper and achieve a real-time DSM, to avoid overloading in the microgrids. However, this research has ...Ibrahim A. Mwammenywa ; [First reviewer: Prof. Dr.-Ing. Ulrich Hilleringmann, Second reviewer: Prof. Dr.-Ing. habil. Stefan Krauter]Tag der Verteidigung: 23.05.2024Universität Paderborn, Dissertation, 202

Chairs of Excellence Annual Report 2022

https://digitalcommons.memphis.edu/govpubs-tn-higher-education-commission-academic-programs-workforce-reports/1018/thumbnail.jp

Assessing Performance Optimization Strategies In Cloud-Native Environments Through Containerization And Orchestration Analysis

This thesis comprises three distinct, yet interconnected studies addressing critical aspects of web infrastructure management. We begin by studying containerization via Docker and its impact on web server performance, focusing on Apache and Nginx hosted on virtualized environments. Through meticulous load testing and analysis, we provide insights into the comparative performance of these servers, adding users of this technology know which webservers to leverage when hosting their webservice along alongside the infrastructure to host it on. Next, we expand our focus to examine the performance of caching systems, namely Redis and Memcached, across traditional VMs and Docker containers. By comparing deployment paradigms and evaluating performance dynamics, we uncover nuanced insights crucial for optimizing resource utilization and throughput management in modern web environments. Finally, we delve into a comprehensive evaluation of two leading Docker orchestration solutions, Docker Swarm and Kubernetes, under constrained environments. Through meticulous benchmarking and analysis, we elucidate the platform’s scalability, responsiveness, and resource utilization, providing valuable guidance for architects and decision-makers navigating containerized deployments. Through these studies, we contribute to the field of web infrastructure management by providing actionable insights, informed decision-making frameworks, and avenues for future research and development

Electric Mobility: An Overview of the Main Aspects Related to the Smart Grid

Electric mobility has become increasingly prominent, not only because of the potential to reduce greenhouse gas emissions but also because of the proven implementations in the electric and transport sector. This paper, considering the smart grid perspective, focuses on the financial and economic benefits related to Electric Vehicle (EV) management in Vehicle-to-Building (V2B), Vehicle-to-Home (V2H), and Vehicle-to-Grid (V2G) technologies. Vehicle-to-Everything is also approached. The owners of EVs, through these technologies, can obtain revenue from their participation in the various ancillary and other services. Similarly, providing these services makes it possible to increase the electric grid’s service quality, reliability, and sustainability. This paper also highlights the different technologies mentioned above, giving an explanation and some examples of their application. Likewise, it is presented the most common ancillary services verified today, such as frequency and voltage regulation, valley filling, peak shaving, and renewable energy supporting and balancing. Furthermore, it is highlighted the different opportunities that EVs can bring to energy management in smart grids. Finally, the SWOT analysis is highlighted for V2G technology.This article is a result of the project RETINA (NORTE-01-0145-FEDER-000062), supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF), and CEECIND/02887/2017 from FCT. We also acknowledge the work facilities and equipment provided by GECAD research center (UIDB/00760/2020) to the project team.info:eu-repo/semantics/publishedVersio

Exploring Successful Strategies for Small Business Owners’ Access to Financing

Considered the drivers of innovations and the engine of the economy, small and medium enterprises (SMEs) represent 99% of U.S. firms. However, nearly 80% of SMEs fail in their 1st year of operation, causing substantial financial hardship to the small business owners and significant loss of tax revenues to local and federal governments. Grounded in the theory of planned behavior, the purpose of this qualitative, pragmatic inquiry was to explore successful strategies that some small business owners use to gain access to financing for their businesses. The participants comprised six small business owners in Norfolk County, Massachusetts, United States, who successfully implemented strategies to access business financing. Data were collected using semistructured interviews. Three themes emerged through thematic analysis: (a) focusing on business needs, (b) leveraging the lender relationship, and (c) taking full advantage of outside advisors. A key recommendation is for small business owners to prioritize the organization, accuracy, and availability of their business’s documentation, ensuring the timely submission of a complete loan package to support their requests for business financing. Implications for positive social change include the potential to increase the approved rate of SMEs’ business loan applications, reduce SMEs\u27 failure rate, and bring about significant societal benefits, such as creating more jobs, increasing tax revenues for the states, and strengthening communities

Effective Business Sustainability Strategies for Small Retail Convenience Stores

Small retail convenience store owners lack sustainability strategies, leading to the business\u27s failure to survive for five years. Retail convenience store owners who fail to implement sustainability strategies for staying in business beyond five years can experience poor customer satisfaction and experience, high operating costs, decreased sales, and low employee morale. Grounded in the sustainability development theory, the purpose of this qualitative multiple case study was to identify and explore the business sustainability strategies small retail convenience store owners in Maryland, U.S.A., use to stay in business beyond 5 years. The participants were four small retail convenience store owners who successfully used sustainability strategies to remain in business beyond five years. Data were collected from semistructured interviews, company archival documents, and field notes and were analyzed using thematic data analysis. Four themes emerged: technology and e-commerce, inventory management, finance and safety, and marketing. A key recommendation is for small convenience store owners to adopt technology and e-commerce with data analysis and reporting capabilities. The implications for positive social change include the potential to improve financial business performance, thereby creating job opportunities, providing social amenities and welfare, and promoting the socioeconomic development of the regional communities