scholarly journals Mitigation strategies for communication networks induced impairments in autonomous microgrids control: A review

2021 ◽  
Vol 5 (4) ◽  
pp. 342-375
Author(s):  
Olayanju Sunday Akinwale ◽  
◽  
Dahunsi Folasade Mojisola ◽  
Ponnle A. Akinlolu ◽  
◽  
...  
Keyword(s):  
High Speed ◽  
Renewable Energy Sources ◽  
Congestion Management ◽  
Mitigation Strategies ◽  
Topology Design ◽  
Effective Control ◽  
Control Methods ◽  
Cyber Attack ◽  
Secondary Control ◽  
The Impact

<abstract> <p>The advancement in communication technology and the availability of intelligent electronic devices (IEDs) have impacted positively on the penetration of renewable energy sources (RES) into the main electricity grid. High penetration of RES also come along with greater demand for more effective control approaches, congestion management techniques, and microgrids optimal dispatch. Most of the secondary control methods of microgrid systems in the autonomous mode require communication links between the distributed generators (DGs) for sharing power information and data for control purposes. This article gives ample review on the communication induced impairments in islanded microgrids. In the review, attention is given to communication induced delay, data packet loss, and cyber-attack that degrades optimal operations of islanded microgrids. The review also considered impairments modelling, the impact of impairments on microgrids operation and management, and the control methods employed in mitigating some of their negative impacts. The paper revealed that innovative control solutions for impairment mitigation rather than the development of new high-speed communication infrastructure should be implemented for microgrid control. It was also pointed out that a sparse communication graph is the basis for communication topology design for distributed secondary control in the microgrid.</p> </abstract>

scholarly journals Factors affecting aerosol size distribution during various dental procedures

2021 ◽  
Author(s):  
Shruti Choudhary ◽  
Michael J Durkin ◽  
Daniel C Stoeckel ◽  
Heidi M Steinkamp ◽  
Martin H Thornhill ◽  
...  
Keyword(s):  
Particulate Matter ◽  
High Speed ◽  
High Volume ◽  
Routine Care ◽  
Mitigation Strategies ◽  
Aerosol Size Distribution ◽  
Dental Clinic ◽  
Factors Affecting ◽  
Dental Procedures ◽  
The Impact

Objectives: To determine the impact of various aerosol mitigation interventions and establish duration of aerosol persistence in a variety of dental clinic configurations. Methods: We performed aerosol measurement studies in endodontic, orthodontic, periodontic, pediatric, and general dentistry clinics. We used an optical aerosol spectrometer and wearable particulate matter sensors to measure real-time aerosol concentration from the vantage point of the dentist during routine care in a variety of clinic configurations (e.g, open bay, single room, partitioned operatories). We compared the impact of aerosol mitigation strategies [ventilation and high-volume evacuation (HVE)] and prevalence of particulate matter in the dental clinic environment before, during and after high-speed drilling, slow speed drilling and ultrasonic scaling procedures. Results: Conical and ISOVAC HVE were superior to standard tip evacuation for aerosol-generating procedures. When aerosols were detected in the environment, they were rapidly dispersed within minutes of completing the aerosol-generating procedure. Few aerosols were detected in dental clinics, regardless of configuration, when conical and ISOVAC HVE were used. Conclusions: Dentists should consider using conical or ISOVAC HVE rather than standard tip evacuators to reduce aerosols generated during routine clinical practice. Furthermore, when such effective aerosol mitigation strategies are employed, dentists need not leave dental chairs fallow between patients as aerosols are rapidly dispersed. Clinical Significance: ISOVAC HVE is highly effective in reducing aerosol emissions. With adequate ventilation and HVE use, dental fallow time can be reduced to 5 minutes.

Modeling of Autonomous Hydrofoil Craft Tracking a Moving Target

2020 ◽  
Vol 08 (02) ◽  
pp. 171-178 ◽  
Author(s):  
Konstantin I. Matveev
Keyword(s):  
Horizontal Plane ◽  
High Speed ◽  
Effective Control ◽  
Moving Target ◽  
Control Methods ◽  
Modeling Effort ◽  
Pure Pursuit ◽  
Marine Vessels ◽  
Marine Vehicle

The interest in autonomous marine vessels has been continuously growing in the recent years. Most platforms of the autonomous surface watercraft involve traditional mono- or multi-hulls. Advanced marine vehicle concepts, such as hydrofoils, can provide high-speed and high seakeeping capabilities. In this study, a modeling effort is initiated for a small autonomous hydrofoil boat intended for intercepting operations. A 3-DOF model, including surge, sway and yaw, is applied for simulating maneuvering motions of the boat in the foilborne state. Forces generated by the propulsor, rudder and struts are accounted for in the simulations of the horizontal-plane boat dynamics. Two scenarios of a hydrofoil boat pursuing a moving target are investigated. In the pure pursuit, the interceptor always attempts to aim at the target and uses full thrust to quickly reach the target at a high speed. In the constant-bearing scenario, the interceptor approaches the target with diminishing speed trying to achieve a rendezvous. The presented models and results can help engineers to design more effective control methods for fast boats intended for intercepting operations.

scholarly journals Impacts of a railway tunnel on the streams baseflow verified by means of numerical modelling

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Leonardo Piccinini ◽  
Valentina Vincenzi
Keyword(s):  
Numerical Modelling ◽  
High Speed ◽  
Three Dimensional ◽  
Tracer Tests ◽  
Maximum Flow ◽  
Mitigation Strategies ◽  
Railway Tunnel ◽  
Flow Measurements ◽  
Railway Line ◽  
The Impact

The high-speed railway line between Bologna and Florence (Italy) is mostly developed underground through the Tuscan-Emilian Apennine, and the tunnels severely impacted groundwater and surface water. The 15-km-long Firenzuola tunnel crosses siliciclastic turbidites: during drilling, water inrushes occurred at fault and fracture zones, and the tunnel continues to drain the aquifer. The water table dropped below the level of the valleys, and gaining streams transformed into losing streams or ran completely dry, as did many springs. Hydrological observations and two multitracer tests have previously characterized the stream-tunnel connections and the impact processes. In the framework of planning mitigation strategies to minimize impacts on stream baseflow, three-dimensional numerical modelling with MODFLOW (the EPM approach) is applied to evaluate the artificial minimum flow needed to maintain flow continuity along the stream during the recession phase. The establishment of the two presented models is based on hydrogeological monitoring data and the results of flow measurements and tracer tests. Maximum flow rates subtracted from stream baseflow by the tunnel along the connection structures are calculated for two streams with major impacts.

scholarly journals Flea Beetle (Coleoptera: Chrysomelidae) Populations, Effects of Feeding Injury, and Efficacy of Insecticide Treatments on Eggplant and Cabbage in Southwest Virginia

2019 ◽  
Vol 113 (2) ◽  
pp. 887-895 ◽  
Author(s):  
James Mason ◽  
Adam Michael Alford ◽  
Thomas Patrick Kuhar
Keyword(s):  
Flea Beetle ◽  
Solanum Melongena ◽  
Effective Control ◽  
Individual Plant ◽  
Control Methods ◽  
Phyllotreta Cruciferae ◽  
Phyllotreta Striolata ◽  
Crucifer Flea Beetle ◽  
Significant Yield ◽  
The Impact

Abstract Flea beetles, are common pests of cabbage Brassica oleracea L. (Brassicales: Brassicaceae) and eggplant Solanum melongena L. (Solanales: Solanaceae), but little is known about the flea beetle populations in Virginia, their impact on yield, or the most effective control methods. This research investigates flea beetle populations and the impact of their feeding injury on cabbage and eggplant in Southwest Virginia and determines the most efficacious control methods. In Whitethorne, VA, cabbage and eggplant crops were vacuum sampled weekly throughout two summers (2015, 2016). Crucifer flea beetle, Phyllotreta cruciferae (Goeze) (Coleoptera: Chrysomelidae), and striped flea beetle, Phyllotreta striolata Fabr. (Coleoptera: Chrysomelidae) were found on cabbage; whereas, eggplant flea beetle, Epitrix fucula (Crotch) (Coleoptera: Chrysomelidae), and the tobacco flea beetle, Epitrix hirtipennis (Melsheimer) (Coleoptera: Chrysomelidae) were found on eggplant. To evaluate the impact of flea beetle feeding on these plants flea beetle densities and defoliation were assessed weekly and individual plant, as well as whole plot yields, assessed at harvest. For cabbage, significant yield reductions were observed between 1 and 20% and &gt;60% defoliation. Similarly, significant yield reductions were observed between 41 and 60% and &gt;60% defoliation for eggplant. The efficacy of various insecticides was also evaluated. Soil application of the systemic neonicotinoid dinotefuran, imidacloprid, and the foliar-applied bifenthrin resulted in the fewest beetles, the least amount of leaf defoliation, and the highest yield in cabbage and eggplant. This research helps vegetable growers to better understand the severity of these pests and how to effectively combat them.

scholarly journals Distributed Control Methods and Impact of Communication Failure in AC Microgrids: A Comparative Review

Electronics ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 1265 ◽  
Author(s):  
Aghaee ◽  
Mahdian Dehkordi ◽  
Bayati ◽  
Hajizadeh
Keyword(s):  
Control Systems ◽  
Distributed Control ◽  
Congestion Management ◽  
Control Methods ◽  
Communication Failure ◽  
Distributed Control Systems ◽  
Advantages And Disadvantages ◽  
Distributed Controller ◽  
Comparative Review ◽  
The Impact

The objectives of this paper are to review and compare the distributed control methods in AC microgrids and also to identify the impact of communication failure on this type of the controller. The current AC microgrids are distinguished from the traditional power system topologies because of the high penetration of advanced control methods, measurements, sensors, power electronic devices, and communication links. Also, because of the increasing integration of renewable energy sources, control strategy for congestion management, frequency control, and optimal dispatch of microgrids has become more complicated. This paper explains the characteristics and features of distributed control systems and discusses the challenges of these approaches. In addition, a comprehensive review of the advantages and disadvantages of these techniques are explained in detail. On the other hand, the possible challenges, related to communication failure, noise, delay, and packet dropout on the operation of the distributed controller are presented, and several techniques, which reduce the impact of communication failure of the distributed controller, are compared. This comprehensive study on distributed control systems reveals the challenges in and future possible studies on this issue.

scholarly journals Centralized Control of Distribution Networks with High Penetration of Renewable Energies

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4283
Author(s):  
Francisco J. Zarco-Soto ◽  
Pedro J. Zarco-Periñán ◽  
Jose L. Martínez-Ramos
Keyword(s):  
Distributed Generation ◽  
Electric Vehicles ◽  
Renewable Energy Sources ◽  
Distribution Networks ◽  
Congestion Management ◽  
Renewable Energies ◽  
Centralized Control ◽  
High Penetration ◽  
Domestic Use ◽  
The Impact

Distribution networks were conceived to distribute the energy received from transmission and subtransmission to supply passive loads. This approach, however, is not valid anymore due to the presence of distributed generation, which is mainly based on renewable energies, and the increased number of plug-in electric vehicles that are connected at this voltage level for domestic use. In this paper the ongoing transition that distribution networks face is addressed. Whereas distributed renewable energy sources increase nodal voltages, electric vehicles result in demand surges higher than the load predictions considered when planning these networks, leading to congestion in distribution lines and transformers. Additionally, centralized control techniques are analyzed to reduce the impact of distributed generation and electric vehicles and increase their effective integration. A classification of the different methodologies applied to the problems of voltage control and congestion management is presented.

scholarly journals Insights into Organizational Security Readiness: Lessons Learned from Cyber-Attack Case Studies

2021 ◽  
Vol 1 (4) ◽  
pp. 638-659
Author(s):  
Faisal Quader ◽  
Vandana P. Janeja
Keyword(s):  
Case Studies ◽  
Comprehensive Evaluation ◽  
Cyber Attacks ◽  
Lessons Learned ◽  
Mitigation Strategies ◽  
Cyber Attack ◽  
Cyber Threats ◽  
Weakest Link ◽  
Behavioral Aspects ◽  
The Impact

This paper focuses on understanding the characteristics of multiple types of cyber-attacks through a comprehensive evaluation of case studies of real-world cyber-attacks. For each type of attack, we identify and link the attack type to the characteristics of that attack and the factors leading up to the attack, as observed from the review of case studies for that type of attack. We explored both the quantitative and qualitative characteristics for the types of attacks, including the type of industry, the financial intensity of the attack, non-financial intensity impacts, the number of impacted customers, and the impact on users’ trust and loyalty. In addition, we investigated the key factors leading up to an attack, including the human behavioral aspects; the organizational–cultural factors at play; the security policies adapted; the technology adoption and investment by the business; the training and awareness of all stakeholders, including users, customers and employees; and the investments in cybersecurity. In our study, we also analyzed how these factors are related to each other by evaluating the co-occurrence and linkage of factors to form graphs of connected frequent rules seen across the case studies. This study aims to help organizations take a proactive approach to the study of relevant cyber threats and aims to educate organizations to become more knowledgeable through lessons learned from other organizations experiencing cyber-attacks. Our findings indicate that the human behavioral aspects leading up to attacks are the weakest link in the successful prevention of cyber threats. We focus on human factors and discuss mitigation strategies.

Modeling of Tread Block Contact Mechanics Using Linear Viscoelastic Theory3

2008 ◽  
Vol 36 (3) ◽  
pp. 211-226 ◽  
Author(s):  
F. Liu ◽  
M. P. F. Sutcliffe ◽  
W. R. Graham
Keyword(s):  
High Speed ◽  
Slip Rate ◽  
Material Model ◽  
Contact Forces ◽  
Block Modeling ◽  
Rate Dependent ◽  
Linear Viscoelastic Material ◽  
Linear Viscoelastic ◽  
The Impact ◽  
Good Agreement

Abstract In an effort to understand the dynamic hub forces on road vehicles, an advanced free-rolling tire-model is being developed in which the tread blocks and tire belt are modeled separately. This paper presents the interim results for the tread block modeling. The finite element code ABAQUS/Explicit is used to predict the contact forces on the tread blocks based on a linear viscoelastic material model. Special attention is paid to investigating the forces on the tread blocks during the impact and release motions. A pressure and slip-rate-dependent frictional law is applied in the analysis. A simplified numerical model is also proposed where the tread blocks are discretized into linear viscoelastic spring elements. The results from both models are validated via experiments in a high-speed rolling test rig and found to be in good agreement.

A MODELING SYSTEM FOR CLIMATE CHANGE RISK ASSESSMENT, MANAGEMENT AND HEDGING IN COASTAL AREAS

2017 ◽  
Author(s):  
Sergei Soldatenko ◽  
Sergei Soldatenko ◽  
Genrikh Alekseev ◽  
Genrikh Alekseev ◽  
Alexander Danilov ◽  
...  
Keyword(s):  
Climate Change ◽  
Risk Assessment ◽  
Coastal Areas ◽  
Mitigation Strategies ◽  
System Structure ◽  
The Arctic ◽  
Risk Modeling ◽  
Wide Range ◽  
Adverse Weather ◽  
The Impact

Every aspect of human operations faces a wide range of risks, some of which can cause serious consequences. By the start of 21st century, mankind has recognized a new class of risks posed by climate change. It is obvious, that the global climate is changing, and will continue to change, in ways that affect the planning and day to day operations of businesses, government agencies and other organizations and institutions. The manifestations of climate change include but not limited to rising sea levels, increasing temperature, flooding, melting polar sea ice, adverse weather events (e.g. heatwaves, drought, and storms) and a rise in related problems (e.g. health and environmental). Assessing and managing climate risks represent one of the most challenging issues of today and for the future. The purpose of the risk modeling system discussed in this paper is to provide a framework and methodology to quantify risks caused by climate change, to facilitate estimates of the impact of climate change on various spheres of human activities and to compare eventual adaptation and risk mitigation strategies. The system integrates both physical climate system and economic models together with knowledge-based subsystem, which can help support proactive risk management. System structure and its main components are considered. Special attention is paid to climate risk assessment, management and hedging in the Arctic coastal areas.

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