Coordination Scheme Research Articles

Distributed Neurodynamics-Based Backstepping Optimal Control for Robust Constrained Consensus of Underactuated Underwater Vehicles Fleet.

Robust constrained formation tracking control of underactuated underwater vehicles (UUVs) fleet in 3-D space is a challenging but practical problem. To address this problem, this article develops a novel consensus-based optimal coordination protocol and a robust controller, which adopts a hierarchical architecture. On the top layer, the spherical coordinate transform is introduced to tackle the nonholonomic constraint, and then a distributed optimal motion coordination strategy is developed. As a result, the optimal formation tracking of UUVs fleet can be achieved, and the constraints are fulfilled. To realize the generated optimal commands better and, meanwhile, deal with the underactuation, at the lower-level control loop a neurodynamics-based robust backstepping controller is designed, and in particular, the issue of "explosion of terms" appearing in conventional backstepping-based controllers is avoided and control activities are improved. The stability of the overall UUVs formation system is established to ensure that all the states of the UUVs are uniformly ultimately bounded in the presence of unknown disturbances. Finally, extensive simulation comparisons are made to illustrate the superiority and effectiveness of the derived optimal formation tracking protocol.

Recent trend and future prospect in optimization of electric vehicle charging: a systematic review

Electric vehicles charging (EVs) must be done optimally to minimize the impact it causes. EVs are being recognized as a potential way to decrease greenhouse gas emissions and combat climate change. However, there are still difficulties in optimizing these systems to minimize operating costs and EVs charging waiting times. This study investigates several industrial, commercial and residential charging stations. The primary objective of this study is to systematically review the existing literature on optimizing EV charging. The collection of data was centered on scholarly articles released between the years 2018 and 2023 from Scopus, IEEE Xplore. This study presents a systematic literature review of optimizing EVs charging. As a result, 43 EVs charging optimization studies were obtained which were investigated and studied further. Identify and analysis the selected studies, there are two research topics and trends most frequently addressed by researchers: scheduling and coordination. The four most applied methods in EVs charging are identified: particle swarm optimization (PSO), genetic algorithm (GA), linear programming (LP) method, and evolutionary algorithms (EA). Future research directions: develop advanced optimization algorithms, investigating the integration of renewable energy sources into the charging infrastructure, exploring the potential of vehicle-to-grid (V2G) services, studying the impact of EVs charging on the power grid and developing strategies, considering the optimization of charging schedules and coordination strategies for large-scale EVs fleets.

Modeling collaborative data service provision around an open source platform under uncertainty with stochastic provision games

This paper uses concepts taken from Cooperative Game Theory to model the incentives to join forces among a group of agents involved in collaborative provision of a mobile app under uncertainty around an open source platform. Demand uncertainty leads the agents to reach a noncooperative equilibrium by offering low quality apps. This can be avoided by introducing a coordination scheme through a common platform that eliminates the effects of lack of information. Coordination is achieved by providing a revenue sharing scheme enforcing the stability of the collaboration but also defined in a “fair” way, depending on the importance of the resources that each provider supplies to the app. To this aim, we introduce the concept of Stochastic Provision Games. This coordination leads both to higher app quality and improved profitability for the participants.

A new fault detection and relay coordination technique for low voltage DC microgrid

Integration of various distributed generation units in the DC distribution network creates an outsized impact on magnitude and direction of fault current. The specific behaviour of fault current during a short circuit fault demands quick and reliable detection and isolation of fault, which poses a significant challenge in developing an effective protection and coordination scheme for DC microgrids. In this regard, a new fault detection and relay coordination algorithm is proposed for a Low voltage DC (LVDC) microgrid, which utilizes inverse time relay characteristics based on variance of fault current. While the relay responds and picks up during both internal and external faults, its operation is automatically limited upon operation of the downstream circuit breaker without the need for any communication channel. The efficacy of the proposed strategy is evaluated by modelling a mesh-connected DC microgrid network using PSCAD/EMTDC software. The protection coordination problem is developed as a constraint non-linear optimization problem to determine optimal relay settings. The proposed approach has been tested by simulating various types of faults at different fault locations and fault resistances along with various microgrid operating modes. The results suggest that the proposed strategy stands out by optimizing relay operating time and providing backup protection while upholding relay coordination. A comparative assessment of the proposed technique with existing ones proves its effectiveness in terms of swift relay tripping time, better immunity against noise, and independency against microgrid operating mode and topology.

Fracture modeling of curved composite shell structures using augmented finite element method

This paper presents an augmented finite element method for the fracture modeling of curved composite shell structures considering geometric nonlinear effects. We first derive the composite shell AFEM (CS-AFEM) formulation using a dynamic implicit algorithm, which enhances the numerical convergence when dealing with unstable crack propagations. Besides, the cohesive zone model featuring with shell kinematics is incorporated into the CS-AFEM to describe the quasi-brittle fracture behaviors of composite laminates. Furthermore, a coordinate transformation scheme is proposed to describe both the local material orientation and the crack evolving path in the curved shell structures. Finally, several benchmark examples are numerically investigated, and the capability of the proposed method in modeling the arbitrary evolving cracks in curved composite shell structures has been thoroughly demonstrated.

Unveiling the overlooked role of structural heterogeneity within Fe-N-C single atom catalysts for Fenton-like reactions: Efficient decontamination of pharmaceuticals from wastewater and source-separated urine

Recognizing the structural heterogeneity of Metal-N-C single atom catalysts (M-N-C SACs) and further revealing the impact of other metal phases that may be generated during the preparation process on the catalytic activity of SACs are essential for the rational design of M-N-C SACs. Through the post-Fe(III)-N coordination strategy, an extremely reactive heterogeneous Fe-N-C SACs including Fe-Nx coordinating sites and carbon-iron hybrids into the N-doped graphene-containing carbon nanoflakes (Fe3C/Fe-Nx@GCN) is designed at the atomic level. As a stabilized Fenton-like activator, the catalyst exhibits a high mass activity of 2.08 × 105 min−1 mol−1 for the catalytic oxidation of recalcitrant organic. The experiments and density functional theory (DFT) calculations reveal that specific type of N-coordinated Fe sites with a lower d-band center position is prone to Fe-oxo species production. However, the incorporation of carbon-iron hybrids induces charge redistribution in the active metal centers, further enhancing catalyst’s adsorption energy on peroxymonosulfate (PMS) and effectively modulating the reaction energy barriers. Additionally, the electron transfer pathway dominated by potential differences was confirmed by appropriate reactive substrate orbital energies. This study preferentially provides perspectives on the synergistic relationship between carbon-iron hybrids and Fe-Nx in PMS-AOPs and proposes the multiple-reaction pathways for eliminating pharmaceuticals from the source-separated urine.

Disaster Management and Emergency Response: Improving Coordination and Preparedness

Disasters pose significant challenges to communities worldwide, necessitating effective disaster management and emergency response systems. This study aims to evaluate current practices in disaster management and emergency response, focusing on enhancing coordination and preparedness. Through qualitative analysis, including literature review and library research, this study assesses existing strategies and identifies areas for improvement. The findings underscore the importance of robust coordination mechanisms among various stakeholders involved in disaster management, including government agencies, non-governmental organizations, and community groups. Moreover, the study highlights the critical role of preparedness measures in mitigating the impact of disasters and facilitating timely and effective response efforts. By synthesizing insights from existing literature and case studies, this research provides valuable recommendations for enhancing disaster management and emergency response frameworks. The results emphasize the need for comprehensive planning, capacity-building initiatives, and the integration of technology to strengthen resilience and response capabilities. Furthermore, the study underscores the significance of community engagement and public awareness campaigns in fostering a culture of preparedness and resilience. Overall, this research contributes to the ongoing discourse on disaster risk reduction and emergency management by offering insights into improving coordination and preparedness strategies in the face of natural and man-made disasters.

Analyzing the boundaries for TSO-DSO coordination when activating flexibility for DSO´s in networks with an expected significant load increase

The Transmission System Operators (TSO) and Distribution System Operators (DSO) coordination literature deals with different coordination schemes or coordination methodologies. However, consumer actions or regular DSO operations continuously affect the system balance operation, and no major coordination is required as these actions individually have negligible impacts on the overall system. The literature has not previously analysed where the limit beyond which coordination is necessary. This question requires an analysis of the DSO operations where the need for coordination is foreseen and a case-by-case study of what type of impacts are created by the activation of the DSO flexibility resources on the responsibilities of the TSO. Such analysis helps to define thresholds and scenarios considering existing changes in distribution networks, which can be a reference for delimitating costly coordination procedures. This paper presents a revision of all the possible scenarios of the DSO operation needs and their impacts on TSO responsibilities considering the possible TSO/DSO borders at different voltage levels. Afterward, a methodology is proposed to analyse more deeply the impact of flexibility activation with an expected significant load increase. Representative case studies evaluate the possible impacts on TSO responsibilities of local flexibility activation. This paper concludes that the impact of local flexibility is expected to be significant when large power changes are managed in the short term, estimated in more than 50 MW if the DSO operates in 132 kV or more than 15 MW if the DSO operates up to 66 kV. At LV or MV level, minor coordination would be needed.

Controllable region analysis of active front steering and differential braking system stability control characterized by additional yaw moment

Active Front Steering (AFS) and Differential Braking System (DBS) are commonly used execution systems for vehicle anti-rollover or handling stability control. They regulate the vehicle’s yaw moment by adjusting the lateral tire force and longitudinal tire force, respectively. However, these two systems differ in terms of control capabilities and regulatory sensitivities. In emergency conditions, it becomes crucial to allocate and coordinate the tasks for the execution systems according to their yaw moment control capability and adjustment sensitivity. This paper proposes a method for calculating the controllable region represented by the additional yaw moment. This method allows for the computation of the control capability of AFS and DBS based on the current state. Additionally, the influence of different vehicle states on the controllable regions of the two execution systems is analyzed. Building upon this analysis, the yaw moment adjustment sensitivities of AFS and DBS systems under the current state are further investigated. Finally, a task coordinated strategy between AFS and DBS is developed based on the analysis of controllable regions and sensitivities of different execution systems. Simulink simulations are conducted on yaw stability and roll stability conditions to comprehensively analyze the working process of the proposed task coordination strategy.

An interactive simulation of control and coordination strategies for swarms of autonomous construction robots

An interactive simulation of control and coordination strategies for swarms of autonomous construction robots

Research on a Self-Coordinated Optimization Method for Distributed Energy Resources Targeting Risk Mitigation

This passage discusses a rapid restoration optimization strategy for short-term global coordination and the synergistic autonomous regulation of distributed energy sources based on a model predictive control framework. A short-term rapid recovery global coordination optimization model is established through the prediction of network states under abnormal conditions. This model includes the energy management of distributed energy sources and recovery plans for critical loads. In terms of the autonomous regulation of distributed energy sources, based on the results of global coordination optimization and aiming to minimize load shedding losses and grid losses, an ultra-short-term rolling control strategy is formulated using power output and load switching as control variables. Finally, simulation analysis on the IEEE 33-node distribution network system indicates that the proposed model and method significantly accelerate the recovery speed of the distribution network and effectively enhance its resilience level.

Lattice-Confined Single-Atom Catalyst: Preparation, Application and Electron Regulation Mechanism.

Lattice-confined single-atom catalyst (LC SAC), featuring exceptional activity, intriguing stability and prominent selectivity, has attracted extensive attention in the fields of various reactions (e.g., hydrogen evolution reaction (HER), oxygen evolution reaction (OER), oxygen reduction reaction (ORR), etc.). To design a "smart" LC SAC for catalytic applications, one must systematically comprehend updated advances in the preparation, the application, and especially the peculiar electron regulation mechanism of LC SAC. In this review, the specific preparation methods of LC SAC based on general coordination strategy are updated, and its applications in HER, OER, ORR, N2 reduction reaction (NRR), advanced oxidation processes (AOPs) and so forth are summarized to display outstanding activity, stability and selectivity. Uniquely, the electron regulation mechanisms are first and deeply discussed and can be primarily categorized as electron transfer bridge with monometallic active sites, novel catalytic centers with polymetallic active sites, and positive influence by surrounding environments. In the end, the existing issues and future development directions are put forward with a view to further optimize the performance of LC SAC. This review is expected to contribute to the in-depth understanding and practical application of highly efficient LC SAC.

Interface chemistry-induced organic-inorganic phosphorus-based hybrid for high fire safety epoxy resin

The organic-inorganic phosphorus-based hybrid flame retardants are attractive owing to the high efficiency in promoting flame retardancy and suppressing the smoke and toxic gases, yet their preparation has been seldom reported. Herein, ammonium polyphosphate (APP) was decorated by organophosphorus triazole (D-ATA) with Fe (III) as the medium through the interfacial coordination strategy for the construction of the hybrid (APP@FeDT), which was expected to address the issues related to the combustibility, harmful smoke and toxic gases of epoxy resin (EP). APP@FeDT showed better compatibility in EP than APP owing to the enhanced roughness and organophosphorus-based triazolyl. Compared to pristine EP, EP with 6 wt% APP@FeDT achieved the UL-94 V-0 rating and the LOI of 29.6 %, and its PHRR, THR and TSP were reduced by 81.4 %, 64.1 % and 66.5 %, respectively. Generally, this work provides a feasible strategy for the preparation of phosphorus-based hybrid flame retardant and reveals its potential application in high fire safety polymers.

An Early and Routinely Collected Applied Cognitive Assessment Is Associated with Post-Acute Care Facility Discharge from the Hospital

Objective: Although patient cognition can have an impact on health services needs once discharged from the hospital, it is typically not evaluated as part of routine care. We aimed to investigate how routinely collected Activity Measure for Post-Acute Care Applied Cognitive Inpatient Short Form (AM-PAC ACISF) scores, a measure of applied cognition, are associated with discharge disposition. Methods: A retrospective analysis was conducted on 5,236 electronic medical records of adult patients admitted in Johns Hopkins Hospital (JHH) between July 1, 2020 to November 2, 2021. Data was evaluated on whether patients who have been admitted across hospital services required post-acute care based on their AM-PAC ACISF scores. A cut-off raw score of 21 or less was considered as having cognitive impairment. Results: The applied cognitive t-scale scores assessed near time of admission were 9.3 points lower in patients discharged to PAC compared to discharge home. Adjusted regression models showed the odds of PAC needs for patients with AM-PAC ACISF t-scale scores in the lowest tertile were 3.4 times greater than patients in the highest tertile (95% CI 2.8,4.0; p <0.001). Patients with scores in the middle tertile have 1.9 times greater odds for PAC needs than those in the highest tertile (95% CI 1.6,2.2; p<0.001). Bivariate and multivariate logistic regression models showed AM-PAC ACISF, living alone, male gender, prior residence outside of home, admission due to general surgery, neurology, or orthopedics services versus medicine service all increased the odds of discharge to PAC (OR 1.2–4.4, p=<0.001). Conclusions: This study provides empirical evidence that a routinely collected cognitive assessment could be a care coordination strategy to help identify patients who are more likely to require PAC after discharge.

In silico validation of a customizable fully-autonomous artificial pancreas with coordinated insulin, glucagon and rescue carbohydrates

Artificial pancreas systems should be designed considering different patient profiles, which is challenging from a control theory perspective. In this paper, a flexible-hybrid dual-hormone control algorithm for an artificial pancreas is proposed. The algorithm handles announced/unannounced meals by means of a non-interacting feedforward scheme that safely incorporates prandial boluses. Also, a coordination strategy is employed to distribute the counter-regulatory actions, which can be delivered as a continuous glucagon infusion via an automated pump, as an oral rescue carbohydrate recommendation, or as a rescue glucagon dose recommendation to be administrated through a glucagon pen. The different configurations of the proposed controller were evaluated in silico using a 14-day virtual scenario with random meal intakes and exercise sessions, achieving above 80% time-in-range and low time spent in hypoglycemia.

Optimal DGs coordination strategy for managing unbalanced and islanded distribution networks

Abstract Distributed generators (DGs) have the potential to act as alternative power sources for balancing and restoring service in distribution system breakdowns. Nevertheless, DGs variety of characteristics and uncertain behavior pose difficulties in optimizing their operation while restoring the system. In this paper, a hierarchical structure is introduced to manage the unbalanced and islanded distribution networks with the optimal coordination strategy of DGs. The proposed approach encompasses multiple control tiers that manage DGs coordination process into three specific levels, each accountable for distinct functions involving voltage and frequency regulation, power distribution within individual islands, and overseeing power exchange between these units for minimizing imbalance and maximizing the load restoration. This research delivers a comprehensive solution for optimally coordinating DGs in unbalanced and isolated networks during restoration, thus elevating system reliability and resilience. The proposed model for distributed control restoration is validated using a modified IEEE 123-bus test setup.

A Novel Multi-Objective Protection Coordination Scheme for a Microgrid with Optimal Deployment of Dual-Setting ROCOV Based Relays

A Novel Multi-Objective Protection Coordination Scheme for a Microgrid with Optimal Deployment of Dual-Setting ROCOV Based Relays

Sabatier phenomenon in chemoselective gas-sensing reactions induced by Ag cluster coordination

The Sabatier principle in heterogeneous catalysis provides guidance for designing optimal catalysts with the highest activity. We report a new Sabatier phenomenon induced by nanoclusters on different atomic scales in gas-sensitive reactions. We prepared a series of Ag nanocluster catalysts with coordination structures ranging from Ag0 to Ag13 through a surface coordination strategy. When used as catalysts for gas-sensitive reactions, a volcano-type relationship between the coordination number of Ag nanoclusters and gas-sensitive activity emerges, with a summit at a moderate coordination of Ag5. Mechanistic studies show that the efficient adsorption of activated *C2H6O on electron-rich Ag5 clusters is a key factor for the Sabatier phenomenon (adsorption energy from −0.322 eV to −0.663 eV), which leads to highly selective sensing. We found that the catalyst electron-rich surface layer induced by Ag5 clusters serves as a descriptor to explain the structure–activity relationship. Furthermore, due to the well-defined geometric and electronic structures in the Ag5 clusters, the optimized catalyst achieves both maximum activity and selectivity in chemoselective sensing reactions. This study reveals the Sabatier principle and provides insightful guidance for the rational design of more efficient and practical nanocluster catalysts for heterogeneous catalysis.

Relation Between Abnormal Spontaneous Brain Activity and Altered Neuromuscular Activation of Lumbar Paraspinal Muscles in Chronic Low Back Pain

ObjectiveTo investigate the neural mechanism underlying functional reorganization and motor coordination strategies in patients with chronic low back pain (cLBP). DesignA case-control study based on data collected during routine clinical practice. SettingThis study was conducted at a university hospital. ParticipantsFifteen patients with cLBP and 15 healthy controls. InterventionsNot applicable. Main Outcome MeasuresWhole brain blood oxygen level-dependent signals were measured using functional magnetic resonance imaging and amplitude of low-frequency fluctuation (ALFF) method to identify pain-induced changes in regional spontaneous brain activity. A novel approach based on the surface electromyogram (EMG) system and fine-wire electrodes was used to record EMG signals in the deep multifidus, superficial multifidus, and erector spinae. ResultsIn cLBP, compared with healthy groups, ALFF was higher in the medial prefrontal, primary somatosensory, primary motor, and inferior temporal cortices, whereas it was lower in the cerebellum and anterior cingulate and posterior cingulate cortices. Furthermore, the decrease in the average EMG activity of the 3 lumbar muscles in the cLBP group was positively correlated with the ALFF values of the primary somatosensory cortex, motor cortex, precuneus, and middle temporal cortex but significantly negatively correlated with the ALFF values of the medial prefrontal and inferior temporal cortices. Interestingly, the correlation between the functional activity in the cerebellum and the EMG activity varied in the lumbar muscles. ConclusionsThese findings suggest a functional association between changes in spontaneous brain activity and altered voluntary neuromuscular activation patterns of the lumbar paraspinal muscles, providing new insights into the mechanisms underlying pain chronicity as well as important implications for developing novel therapeutic targets of cLBP.

Hierarchical coordination scheme for voltage-aware fast frequency provision with flexible loads

Fast-frequency reserve (FFR) is required to counteract the limited system damping in renewable-rich power systems. Several distributed resources, such as batteries, PVs, and thermal loads, suit this role. However, since the devices are located in distribution grids, local constraints must be considered in the control design. In this work, a coordination scheme is developed to provide FFR without local frequency measurements while using limited communication to the central agent and a neighborhood support system to support local voltages. The proposed scheme is tested through time-domain simulations under diverse grid conditions. The coexistence with other local droop control is evaluated, demonstrating how different types of units with flexible active and reactive power production/consumption can coexist with this scheme. The results highlight that the coordination scheme is a promising alternative to local droop control and can coexist with other schemes.