Lyapunov-Based Output Containment Control of Heterogeneous Multi-Agent Systems With Markovian Switching Topologies and Distributed Delays

This paper considers the mean square output containment control problem for heterogeneous multi-agent systems(MASs)with randomly switching topologies and nonuniform distributed delays.By modeling the switching topologies as a continuous-time Markov process and taking the distributed delays into consideration,a novel distributed containment observer is proposed to estimate the convex hull spanned by the leaders'states.A novel distributed output feedback containment controller is then designed without using the prior knowledge of distributed delays.By constructing a novel switching Lyapunov functional,the output containment control problem is then solved in the sense of mean square under an easily-verifiable sufficient condition.Finally,two numerical examples are given to show the effectiveness of the proposed controller.

Group-Consensus of Hierarchical Containment Control for Linear Multi-Agent Systems

The existing containment control has been widely developed for several years, but ignores the case for large-scale cooperation. The strong coupling of large-scale networks will increase the costs of system detection and maintenance. Therefore, this paper is concerned with an extensional containment control issue, hierarchical containment control. It aims to enable a multitude of followers achieving a novel cooperation in the convex hull shaped by multiple leaders. Firstly, by constructing the three-layer topology, large-scale networks are decoupled. Then,under the condition of directed spanning group-tree, a class of dynamic hierarchical containment control protocol is designed such that the novel group-consensus behavior in the convex hull can be realized. Moreover, the definitions of coupling strength coefficients and the group-consensus parameter in the proposed dynamic hierarchical control protocol enhance the adjustability of systems. Compared with the existing containment control strategy, the proposed hierarchical containment control strategy improves dynamic control performance. Finally, numerical simulations are presented to demonstrate the effectiveness of the proposed hierarchical control protocol.

Team-based fixed-time containment control for multi-agent systems with disturbances

We investigate the fixed-time containment control(FCC)problem of multi-agent systems(MASs)under discontinuous communication.A saturation function is used in the controller to achieve the containment control in MASs.One difference from using a symbolic function is that it avoids the differential calculation process for discontinuous functions,which further ensures the continuity of the control input.Considering the discontinuous communication,a dynamic variable is constructed,which is always non-negative between any two communications of the agent.Based on the designed variable,the dynamic event-triggered algorithm is proposed to achieve FCC,which can effectively reduce controller updating.In addition,we further design a new event-triggered algorithm to achieve FCC,called the team-trigger mechanism,which combines the self-triggering technique with the proposed dynamic event trigger mechanism.It has faster convergence than the proposed dynamic event triggering technique and achieves the tradeoff between communication cost,convergence time and number of triggers in MASs.Finally,Zeno behavior is excluded and the validity of the proposed theory is confirmed by simulation.

Review of the prevalence,diagnostics,and containment measures of the current mpox outbreak

Monkeypox(mpox),is a disease from the Poxviridae family that can cause several serious medical issues.This mini-review sought to analyze the existing literature regarding the current mpox outbreak with a focus on the prevalence,diagnostics,and containment measures.Mpox cases have been reported to World Health Organization(WHO)from 85 Member States in all six WHO regions during the period of January 1,2022,through August 3,2022.Standardized or optimized guidelines for the clinical care of patients with mpox are limited,particularly in low-resource settings.In an effort to achieve guidance and meet standards,special attention should be paid to this outbreak in order to eradicate such a rare infectious disease by analyzing prevention and control measures.Patient outcomes may also be poor,and their illnesses may last for a long time.The spectrum of clinical symptoms,including complications and sequelae,as well as aspects of the illness may be indicators of sickness severity and complications;therefore,its clinical presentation must be better understood to improve containment measures.In addition,it is important to create and evaluate a standard of care that takes a variety of parameters into account,including antiviral,immune therapies,and clinical metrics that are particular to mpox.The global emergence of mpox has presented new challenges for public health and has called for further investigation into its epidemiological profile across international contexts.

Thermal-hydraulic and stress analysis of AP1000 reactor containment during LOCA in dry cooling mode

Some kinds of break in the reactor coolant system may cause the coolant to exit rapidly from the failure site,which leads to the loss of coolant accident(LOCA).In this paper,a stress analysis of an AP1000 reactor containment is performed in an LOCA,with the passive containment cooling system(PCCS) being available and not available for cooling the wall's containment.The variations in the mechanical properties of the wall's containment,including elastic modulus,strength,and stress,are analyzed using the ABAQUS code.A general two-phase model is applied for modeling thermal-hydraulic behavior inside the containment.Obtained pressure and temperature from thermal-hydraulic models are considered as boundary conditions of the ABAQUS code to obtain distributions of temperature and stress across steel shell of the containment in the accident.The results indicate that if the PCCS fails,the peak pressure inside the containment exceeds the design value.However,the stress would still be lower than the yield stress value,and no risk would threaten the integrity of the containment.

Containment Control of Fractional Order Multi-Agent Systems With Time Delays

In complex environments, many distributed multiagent systems are described with the fractional-order dynamics.In this paper, containment control of fractional-order multiagent systems with multiple leader agents are studied. Firstly,the collaborative control of fractional-order multi-agent systems(FOMAS) with multiple leaders is analyzed in a directed network without delays. Then, by using Laplace transform and frequency domain theorem, containment consensus of networked FOMAS with time delays is investigated in an undirected network, and a critical value of delays is obtained to ensure the containment consensus of FOMAS. Finally, numerical simulations are shown to verify the results.

Simulation of hydrogen distribution and effect of Engineering Safety Features (ESFs) on its mitigation in a WWER-1000 containment

In this study, thermal–hydraulic parameters inside the containment of aWWER-1000/v446 nuclear power plant are simulated in a double-ended cold leg accident for short and long times (by using CONTAIN 2.0 and MELCOR 1.8.6 codes), and the effect of the spray system as an engineering safety feature on parameters mitigation is analyzed with the former code. Along with the development of the accident from design basis accident to beyond design basis accident, the Zircaloy–steam reaction becomes the source of in-vessel hydrogen generation. Hydrogen distribution inside the containment is simulated for a long time (using CONTAIN and MELCOR), and the effect of recombiners on its mitigation is analyzed (using MELCOR). Thermal–hydraulic parameters and hydrogen distribution profiles are presented as the outcome of the investigation. By activating the spray system, the peak points of pressure and temperature occur in the short time and remain belowthe maximumdesign values along the accident time. It is also shown that recombiners have a reliable effect on reducing the hydrogen concentration below flame propagation limit in the accident localization area. The parameters predicted by CONTAIN and MELCOR are in good agreement with the final safety analysis report. The noted discrepancies are discussed and explained.

Investigation of ex-vessel core catcher for SBO accident in VVER-1000/V528 containment using MELCOR code

To mitigate consequences of core melting,an ex-vessel core catcher is investigated in this study.Instructions should be obeyed to cool down the corium caused by core melting.The corium destroys the reactor containment and causes radioactive materials to be released into the environment if it does not cool down well.It is important to build a core catcher system for the reception,localization,and cool down of the molten corium during a severe accident resulting from core melting.In this study,the role of a core catcher in the VVER-1000/v528 reactor containment during a station black out(SBO)accident is evaluated using the MELCOR1.8.6 code.In addition,parametric analyses of the SBO for(i)SBO accidents with emergency core cooling system(ECCS)operation,and(ii)without ECCS operation are performed.Furthermore,thermal–hydraulic analyses in dry and wet cavities with/without water are conducted.The investigations include the reduction of gases resulting from molten–corium–concrete interactions(H_(2),CO,CO_(2)).Core melting,gas production,and the pressure/temperature in the reactor containment are assessed.Additionally,a full investigation pertaining to gas release(H_(2),CO,CO_(2))and the pressure/temperature of the core catcher is performed.Based on MELCOR simulations,a core cavity and a perimeter water channel are the best options for corium cooling and a lower radionuclide release.This simulation is also theoretically investigated and discussed herein.The simulation results show that the core catcher system in addition to an internal sacrificial material reduces the containment pressure from 689 to 580 kPa and the corresponding temperature from 394 to 380 K.Furthermore,it is observed that the amount of gases produced,particularly hydrogen,decreased from 1698 to 1235 kg.Moreover,the presence of supporting systems,including an ECCS with a core catcher,prolonged the core melting time from 16,430 to 28,630 s(in an SBO accident)and significantly decreased the gases produced.

Distributed Containment Control of Networked Nonlinear Second-order Systems With Unknown Parameters

In this paper, we study the containment control problem for nonlinear second-order systems with unknown parameters and multiple stationary/dynamic leaders. The topologies that characterize the interaction among the leaders and the followers are directed graphs. Necessary and sufficient criteria which guarantee the control objectives are established for both stationary leaders(regulation case) and dynamic leaders(dynamic tracking case) based protocols. The final states of all the followers are exclusively determined by the initial values of the leaders and the topology structures. In the regulation case, all the followers converge into the convex hull spanned by the leaders,while in the dynamic tracking case, not only the positions of the followers converge into the convex hull but also the velocities of the followers converge into the velocity convex hull of the leaders.Finally, all the theoretical results are illustrated by numerical simulations.

Improving Concrete Containment Structures Associated with Fixed-Cone Valves

Fixed-Cone valves are often used to dissipate energy and regulate flow at the low level outlet works of dams. Fixed-Cone valves, also known as Howell-Bunger valves, create an expanding conical jet allowing the energy of the water to dissipate over a large area. However, in many applications constructing the large stilling basin necessary for these valves is either not possible or not feasible. In order to reduce the relative size of the stilling basin, hoods or concrete containment structures have been used in conjunction with Fixed-Cone valves. This paper discusses the use of baffles in concrete containment structures in order to dissipate energy in a considerably confined space. It was determined that using baffles, in place of a deflector ring and end sill (Used in traditional containment structures.), significantly improves the function of containment structures by reducing downstream flow velocities and improving flow patterns and stability. This information will be useful to engineers allowing them to minimize scour and erosion associated with concrete containment structures.

Recent emergence and outbreak of rotavirus gastroenteritis in Samoa:A scoping review of risk factors,containment measures and public health preparedness

Diarrheal diseases have been known to cause death in many children below the age of five years,and rotavirus infection represents a major health problem in the world today,particularly in developing countries.The recent outbreak of rotavirus gastroenteritis in Samoa led to the introduction of her debut national immunization program on rotavirus vaccination for infants.Despite the introduction of anti-viral and anti-emetic drugs as of the containment approaches towards the virus,risk factors,preventive measures and public health preparedness against rotavirus infection are poorly understood in Samoa.This review aims to use available evidence on rotavirus literature to elucidate and map preventive strategies for the recently emerged rotavirus infections in Samoa.We conducted a search strategy using online medical literature databases and retrieval systems.A designated set of keywords such as rotavirus,gastroenteritis,outbreak,risk factors,containment measures,vaccination and Samoa were inserted in electronic databases to retrieve articles.The databases included Pub Med,Google Scholar,MEDLINE,Scinapse,and EBSCO host.Findings from this review addressed the impact of rotavirus infection,associated threats and other preventive measures.Introducing useful health frameworks in pursuing possible methods such as improved water quality,exclusive breast feeding,improved laboratory diagnostics and outbreak surveillance,may be essential in addressing alternate approaches towards containment of the disease in Samoa and other Pacific Island Countries and Territories.

Distributed Robust Containment Control of Linear Heterogeneous Multi-Agent Systems:An Output Regulation Approach

In this paper,we consider the robust output containment problem of linear heterogeneous multi-agent systems under fixed directed networks.A distributed dynamic observer based on the leaders’measurable output was designed to estimate a convex combination of the leaders’states.First,for the case of followers with identical state dimensions,distributed dynamic state and output feedback control laws were designed based on the state-coupled item and the internal model compensator to drive the uncertain followers into the leaders’convex hull within the output regulation framework.Subsequently,we extended theoretical results to the case where followers have nonidentical state dimensions.By establishing virtual errors between the dynamic observer and followers,a new distributed dynamic output feedback control law was constructed using only the states of the compensator to solve the robust output containment problem.Finally,two numerical simulations verified the effectiveness of the designed schemes.

Effects of policies and containment measures on control of COVID- 19 epidemic in Chongqing

BACKGROUND Coronavirus disease 2019(COVID-19)is an emerging,rapidly evolving disease that spreads through the respiratory system and is highly contagious.In March 2020,the World Health Organization declared the COVID-19 outbreak a pandemic.In China,the pandemic was controlled after 2 mo through effective policies and containment measures.Describing the detailed policies and containment measures used to control the epidemic in Chongqing will provide a reference for the prevention and control of COVID-19 in other areas of the world.AIM To explore the effects of different policies and containment measures on the control of the COVID-19 epidemic in Chongqing.METHODS Epidemiological data on COVID-19 in Chongqing were prospectively collected from January 21 to March 15,2020.The policies and prevention measures implemented by the government during the epidemic period were also collected.Trend analysis was performed to explore the impact of the main policy measures on the effectiveness of the control of COVID-19 in Chongqing.As of March 15,the cumulative incidence of COVID-19 in Chongqing was 1.84/100000(576 cases)and the infection fatality rate was 1.04%(6/576).The spread of COVID-19 was controlled by effective policies that involved establishing a group for directing the COVID-19 epidemic control effort;strengthening guidance and supervision;ensuring the supply of daily necessities and medical supplies and equipment to residents;setting up designated hospitals;implementing legal measures;and enhancing health education.Medical techniques were implemented to improve the recovery rate and control the epidemic.Policies such as“the lockdown of Wuhan”,“initiating a first-level response to major public health emergencies”,and“implementing the closed management of residential communities”significantly curbed the spread of COVID-19.Optimizing the diagnosis process,shortening the diagnosis time,and constructing teams of clinical experts facilitated the provision of“one team of medical experts for each patient”treatment for severe patients,which significantly improved the recovery rate and reduced the infection fatality rate.CONCLUSION The prevention policies and containment measures implemented by the government and medical institutions are highly effective in controlling the spread of the epidemic and increasing the recovery rate of COVID-19 patients.

Prevalence, Knowledge and Self-Reported Containment Practices about Bedbugs in the Resource-Limited Setting of Ethiopia: A Descriptive Cross-Sectional Survey

Over the past decade, a dramatic rise in bedbug resurgence has become one of the top potential public health hazards. This study was conducted to determine prevalence, knowledge and self-reported containment practices about bedbugs in the resource-limited setting of Ethiopia. A community based, cross-sectional survey was conducted between January and May 2014. Selected 260 respondents were interviewed by the administration of a pre-tested questionnaire on knowledge and practices about bedbug infestation in the resource-limited setting of Ethiopia. Overall, 91.6% (238/260) of the residents had ample awareness on bedbug infestation. The majority of them (97.2%) extremely bothered about infestations because of bad odors (83.8%), insomnia (79.8%), biting (66.9%), and skin rashes (56.9%). A high prevalence of infestation (72.7%) was observed. Bedrooms and main hall/salon were identified as potential high-risk areas. Chi-square exhibited a strong association between sanitary status and housing conditions (χ2 = 40.91;df = 4;P = 0.0001). Besides, there was a strong association between respondents’ monthly income (χ2 = 42.1;df = 6;P = 0.0001) and educational status (χ2 = 26.01;df = 5;P = 0.0001) with the presence or absence of bedbug infestation. Though the majority of respondents had adequate knowledge, they suffer with deprived practices attributable to deficient resources as well as negligence/ignorance. This study emphasizes the following key interventions: 1) community-based awareness campaigns, 2) implementation of sustainable preventive/containment strategies, 3) educational interventions to ensure translation of knowledge into practices, and 4) the implementation of appropriate poverty alleviation programs to enhance the local-residents living-standard in the future.

Inflammatory bowel disease:Efficient remission maintenance is crucial for cost containment

The inflammatory bowel diseases(IBD) are chronicincurable inflammatory disorders of the gut. Some 10% run a downhill course, requiring emergency medical support and often surgery; another small subset are monogenic, and, threatening pediatric patients, are the challenge of these days. The majority of the IBDs, however, are polygenic low-penetrance diseases, running a lifetime waxing-and-waning course. The prevalent trend is towards a slow worsening and steady cost increase. Each and all drugs of the available arsenal exhibit strengths and weaknesses: Mesalamines are chiefly effectively for mildmoderate colitis, and do not work in Crohn's; steroids do not control some 40% of the ulcerative colitis cases, and are not indicated for Crohn's; thiopurines are effective in the maintenance of the IBDs but do not prevent relapses on withdrawal; biologics are still being used empirically(not monitored) causing further increase of their cost over that of hospitalization. Against all these caveats, two simple rules still hold true: Strict adherence maintenance and avoidance of colitogenic drugs. This matter is expanded in this minireview.

Need for Containment as a Motivation for Facebook Use

Research reveals a mixed picture regarding Facebook uses and psychological effects associated with them. This study looks at this issue through the lens of the psychoanalytic concept of containment. We combined this concept with the anxious and avoidant forms of attachment to create a framework with which to investigate the active and passive uses of Facebook. Using a questionnaire administered to 275 Israeli students, we established that the need for containment predicted logging onto and posting on Facebook after negative experiences. In addition, fulfillment of one’s need for containment was associated with posting on Facebook. We also observed a positive change in one’s feelings about oneself and one’s subjective sense of visibility after posting on Facebook. These results offer a new approach to exploring both Facebook use and its effects.

A Short Note on Containment Scheme against Spreading of Novel Coronavirus COVID-19

A two-stage containment scheme is proposed to minimize spreading of the novel coronavirus. Two stages of quarantine each of 14 days will be involved.

Case Study of Reactor Containment Building Construction in Nuclear Power Plant

It is very important to reduce the construction duration of the Reactor Containment Building (RCB) when considering the more than 50 months on average from concrete placement to completion. Through a case study, this study performs a pre-study for the reduction of construction duration in nuclear power plant project based on construction process of the RCB. The actual data of the case study have been collected and analyze the process and the external wall drawings of the RCB with construction practitioners. As a result of that, it is necessary to modularize the external wall form for equipment hatch and to extend the height of one layer of the external wall form to reduce the construction duration of RCB. The results of this study will be utilized to reduce construction duration of the nuclear power plant.

Balancing Development and Security in the Context of Containment and Pressure by the United States

The United States is launching an all-out crackdown against China in the name of competition,which has posed increasingly severe challenges to development and security in China.The strategic competition between China and the United States is becoming an essential part of once-in-a-century changes that is shaping the world today.Under such circumstances,the Communist Party of China applies a holistic approach to national security,which aims to balance development and security as well as opening up and security.Furthermore,it intends to implement the national rejuvenation strategy within the wider context of once-ina-century global changes.Managing China’s affairs well to achieve a dynamic balance and positive interaction among high-quality development,high-level security,and high-standard opening-up can provide the basis for realizing the rejuvenation of the Chinese nation and response to containment by the United States.While fostering a new development paradigm,China advances scientific and technological innovation and pursues common prosperity.Moreover,it defends national security through firm but flexible struggles and promotes safe development by accelerating domestic circulation.However,China needs to control the costs of its security investment,pay equal attention to the risks and gains brought about by its opening-up policy,and,thus,enhance its capability to compete with the United States in the long term.

A Study on the Structural Response of a PSC Inner Containment Dome with Large Openings Due to Prestress Transfer

A linear three dimensional finite element (FE) study has been carried out to examine the structural response of a prestressed concrete (PSC) inner containment (IC) dome of reactor building (double containment system) of a typical Indian Nuclear Power Plant, having large steam generator (SG) openings with due emphasis on the local behaviour of the steel-concrete interfaces at the SG openings, due to initial prestress transfer. The predominant thrust of the study has been placed on the objective of predicting the possibilities of separation at the steel-concrete interface zones adjacent to the embedded plates (EPs) of the SG openings. Two types of modeling and analysis have been made to study the overall and local behaviour of the structure. Prestressing ducts, passive reinforcements and EPs have been included in the models in certain ways. For the FE analysis, the interface zone has been modeled using interface elements, the properties of which were derived from the results of past experiments conducted on steel plate-concrete inter-face specimens. The FE analysis results have been compared with the results of the past two FE analytical studies on the linear behaviour of the same PSC IC dome. Important observations have been made regarding dome deformation and stresses throughout the structure with special emphasis on the local behaviour of steel-concrete interfaces at and around the SG openings.