Reconfiguration Scheme Research Articles

Pyridine-induced caused structural reconfiguration forming ultrathin 2D metal–organic frameworks for the oxygen evolution reaction

2D Co MOF-Py3 is synthesized by a bottom-up structural reconfiguration strategy by using pyridine for the oxygen evolution reaction.

Resilience evaluation and optimization for an air-ground cooperative network

<abstract> <p>The combat domain of modern warfare is becoming increasingly multidimensional. It is important to evaluate the resilience of the air-ground cooperative network for defending against attack threats and recovery performance. First, a resilience analysis model was proposed to effectively analyze and evaluate the resilience of the air-ground cooperative network. Then, considering the available resources, three dynamic reconfiguration strategies were given from the global perspective to help the air-ground cooperative network quickly recover performance and enhance combat capabilities. Finally, a typical 50-node network was taken as an example to prove the effectiveness and feasibility of the proposed model. The proposed method can provide scientific guidance for improving the air-ground cooperative network combat capabilities.</p> </abstract>

Supply Restoration of Data Centers in Flexible Distribution Networks With Spatial-Temporal Regulation

The reliable operation of Internet data centers (IDCs) is crucial to digitization transformation of society. However, the extreme fault on the IDC-located distribution network is fatal to IDC operation. The evolution of flexible distribution networks (FDNs) can satisfy the deep de-pendence of IDC on high-quality and reliable power supply. In FDNs, AC/DC feeders with multiple voltage levels can be flexibly interconnected and adjusted by flexible stations (FSs). It is promising to flexibly enhance operation per-formance of crucial IDCs after fault isolation in FDNs. In this paper, a coordinated supply restoration method of IDCs in FDNs with spatial-temporal regulation is proposed to minimize IDC data-dropping loss under complex faults. First, a spatial-temporal transfer strategy of IDC work-loads is precisely formulated and an FS-based network reconfiguration strategy is proposed. Then, a mixed-integer second-order conic programming model is established for efficient solving. Spatial-temporal coordination among the source, network, storage, and demand sides can be realized without violating physical feasibility. Finally, the proposed method is validated on the modified IEEE 33-node and modified IEEE 123-node test cases. Case studies show that total outage loss is effectively reduced with sufficient utili-zation of available power. Operational performance of FDN is also enhanced under extreme faults.

Fe-induced crystalline-amorphous interface engineering of a NiMo-based heterostructure for enhanced water oxidation.

Engineering heterostructures with a unique surface/interface structure is one of the effective strategies to develop highly active noble-metal-free catalysts for the oxygen evolution reaction (OER), because the surface/interface of catalysts is the main site for the OER. Herein, we design a coralloid NiMo(Fe)-20 catalyst with a crystalline-amorphous interface through combining a hydrothermal method and an Fe-induced surface reconfiguration strategy. That is, after Fe3+ impregnation treatment, the Ni(OH)2-NiMoO4 pre-catalyst with a complete crystalline surface is restructured into a trimetallic heterostructure with a crystalline-amorphous interface, which facilitates mass diffusion and charge transfer during the OER. As expected, self-supported NiMo(Fe)-20 exhibits excellent electrocatalytic water oxidation performance (overpotential: η-10 = 220 mV, η-100 = 239 mV) in the alkaline electrolyte, and its electrocatalytic performance hardly changes after maintaining the current density of 50 mA cm-2 for 10 hours. Furthermore, nickel foam (NF) supported commercial Pt/C and self-supported NiMo(Fe)-20 served as the cathode and anode of the Pt/C‖NiMo(Fe)-20 electrolyzer, respectively, which exhibits a lower cell voltage (E-100 = 1.53 V) than that of the Pt/C‖RuO2 electrolyzer (E-100 = 1.58 V) assembled with noble metal-based catalysts. The enhanced electrocatalytic performance of the NiMo(Fe)-20 catalyst is mainly attributed to the synergistic effect between the crystalline-amorphous interface and the coralloid trimetallic heterostructure.

SFC active reconfiguration based on user mobility and resource demand prediction in dynamic IoT-MEC networks.

To achieve secure, reliable, and scalable traffic delivery, request streams in mobile Internet of Things (IoT) networks supporting Multi-access Edge Computing (MEC) typically need to pass through a service function chain (SFC) consisting of an ordered series of Virtual Network Functions (VNFs), and then arrive at the target application in the MEC for processing. The high mobility of users and the real-time variability of network traffic in IoT-MEC networks lead to constant changes in the network state, which results in a mismatch between the performance requirements of the currently deployed SFCs and the allocated resources. Meanwhile, there are usually multiple instances of the same VNF in the network, and proactively reconfiguring the deployed SFCs based on the network state changes to ensure high quality of service in the network is a great challenge. In this paper, we study the SFC Reconfiguration Strategy (SFC-RS) based on user mobility and resource demand prediction in IoT MEC networks, aiming to minimize the end-to-end delay and reconfiguration cost of SFCs. First, we model SFC-RS as Integer Linear Programming (ILP). Then, a user trajectory prediction model based on codec movement with attention mechanism and a VNF resource demand prediction model based on the Long Short-Term Memory (LSTM) network are designed to accurately predict user trajectories and node computational and storage resources, respectively. Based on the prediction results, a Prediction-based SFV Active Reconfiguration (PSAR) algorithm is proposed to achieve seamless SFC migration and routing update before the user experience quality degrades, ensuring network consistency and high quality service. Simulation results show that PSAR provides 51.28%, 28.60%, 21.75%, and 16.80% performance improvement over the existing TSRFCM, DDQ, OSA, and DPSM algorithms in terms of end-to-end delay reduction, and 33.32%, 18.94%, 67.42%, and 60.61% performance optimization in terms of reconfiguration cost reduction.

A data-driven configurability evaluation method for spacecraft control systems

<p style='text-indent:20px;'>To release severe constraints of spacecraft on orbit resources (in-cluding computing resources, hardware resources and energy resources), the data-driven reconfigurability evaluation of spacecraft attitude control system is studied in this paper. Firstly, the reconfiguration capability is quantitatively described based on the data forms of stable kernel representation and stable image representation of spacecraft control system subject to noise. Then, based on the obtained reconfigurability index, the maximum boundary of system re-configurability is given, which provides theoretical guidance for the design of autonomous reconfiguration strategy. Finally, an example is employed to verify the effectiveness and correctness of the proposed method.</p>

A Scalable Hierarchical Dynamic PV Array Reconfiguration under Partial Shading

Photovoltaic (PV) arrays are often affected by partial shading (PS), which can significantly reduce their power output. Dynamic reconfiguration is a promising technique for mitigating the negative effects of PS by adjusting the electrical connections of the PV modules in real-time. This paper introduces a hierarchical-based switching block scheme for the dynamic reconfiguration of PV arrays under PS conditions. With the aim of mitigating the negative impact of PS on PV arrays, the proposed system employs a low complexity and easily scalable architecture, making it well-suited for practical applications. Comparative assessments against conventional configurations such as bridge-linked (BL), total-cross-tied (TCT), and series–parallel (SP) reveal superior energy harvesting efficiency for the proposed system under various shading conditions. The hierarchical switching block architecture, featuring multiple levels of switching blocks, enables efficient and flexible reconfiguration of the PV array, even in the presence of complex shading patterns. Through extensive simulations, the system consistently outperforms conventional configurations by adapting effectively to changing shading patterns and optimizing the PV array’s output. The proposed switching block (SB) reconfiguration technique significantly outperforms existing methods like TCT, Sudoku, dynamic proposals, and Magic Square in terms of both power generation (up to 42.52% increase) and efficiency (up to 42.13% improvement) under diverse partial shading conditions. The proposed hierarchical-based switching block scheme thus presents a promising solution for enhancing the dynamic reconfiguration of PV arrays under PS conditions, offering a balance between low complexity, scalability, and superior energy harvesting efficiency for practical applications in the realm of solar energy.

Mineral Phase Reconfiguration Enables the High Enzyme-like Activity of Vermiculite for Antibacterial Application.

Phyllosilicates-based nanomaterials, particularly iron-rich vermiculite (VMT), have wide applications in biomedicine. However, the lack of effective methods to activate the functional layer covered by the external inert layer limits their future applications. Herein, we report a mineral phase reconfiguration strategy to prepare novel nanozymes by a molten salt method. The peroxidase-like activity of the VMT reconfiguration nanozyme is 10 times that of VMT, due to the electronic structure change of iron in VMT. Density-functional theory calculations confirmed that the upward shifted d-band center of the VMT reconfiguration nanozyme promoted the adsorption of H2O2 on the active iron sites and significantly elongated the O-O bond lengths. The reconfiguration nanozyme exhibited nearly 100% antibacterial activity toward Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), much higher than that of VMT (E. coli 10%, S. aureus 21%). This work provides new insights for the rational design of efficient bioactive phyllosilicates-based nanozyme.

Channel reconfiguration distributed interference alignment for multi-unit over-the-air computation

Over-the-air computation (AirComp) has been widely studied as an emerging technique for efficient data aggregation. In multi-unit AirComp networks, inter-unit interference seriously affects the data aggregation performance. To solve the above problem, in this paper, a novel scheme of channel reconfiguration distributed interference alignment (CRDIA) is proposed. We virtualize several devices within a unit as one transmitting device, reconstruct the channel matrix of the system, and iterate iteratively design the pre-processing and post-processing components. Based on the above, the pre-processing matrices of AirComp devices and the post-processing matrices of fusion centers are designed. The sum rate of the system is used as a metric for interference cancellation and mean-squared error (MSE) is used as a metric for data aggregation accuracy. We evaluate the proposed scheme by simulating a network with various numbers of AirComp devices and units. The simulation results show that the CRDIA scheme can achieve accurate computation of the AirComp objective function without inter-unit interference.

Feasibility analysis and saturation control for underactuated spacecraft formation reconfiguration in elliptic orbits

This work proposes a saturation control scheme for underactuated spacecraft formation reconfiguration in elliptic orbits without radial or along-track thrust. Firstly, the rank criterion method is applied to analyze the controllability and feasibility of formation reconfiguration by linearizing the linear time-varying dynamics to linear time-invariant ones. Based on the inherent coupling of the linear time-varying system, the underactuated error dynamics are presented for either underactuated case. Subsequently, the developed underactuated saturation controller can ensure that the time-varying system trajectory asymptotically converges to the specified configuration. The Lyapunov-based analysis presents the constraint conditions of controller parameters and the stable reconfiguration accuracy of the system states. Finally, numerical simulations for both underactuated scenarios are performed in the environment with J2 perturbation to verify the validity of the proposed underactuated control scheme.

3D Reconfigurable Vectorial Holography via a Dual‐Layer Hybrid Metasurface Device

AbstractMetasurface‐based vectorial holography manifests itself as an advanced platform for large‐capacity information storage, holographic display, and cryptography. However, a convenient and effective reconfigurable vectorial hologram generation mechanism still remains a challenge. Here, a rotation‐driven reconfigurable vectorial holography scheme is developed via a dual‐layer hybrid metasurface device, in which radiation‐type and birefringent metasurfaces are cascaded hybridly. Thus, reconfigurable and highly customizable intensity and polarization response of holograms in the 3D space is achieved. Rotatable radiation‐type metasurface (RTM) serves as an incidence‐wavefront modulator to excite the non‐rotatable birefringent metasurface (BM). The gradient descent optimization inverse design method is introduced to achieve the high‐efficiency reconstruction of the Jones vector and Jones matrix distribution on both RTM and BM. On this basis, numerical analysis and experimental verification of 3‐D reconfigurable vectorial holography are demonstrated in the microwave region. This scheme implies a new paradigm for 3‐D reconfigurable vectorial holography and can lead to advances in high‐capacity optical display, switchable meta‐devices, and cryptography.

Cloud-Edge Collaboration-Based Distribution Network Reconfiguration for Voltage Preventive Control

The distribution network reconfiguration can realize the voltage preventive control of the distribution network under alert state, which solves the voltage security issues and maintains the safe operation of distribution network. However, since the great scale and complexity of distribution network would make the traditional centralized distribution network reconfiguration method have a heavy computing burden, a distribution network reconfiguration method based on cloud-edge collaborative architecture for voltage preventive control is proposed, which can reduce the huge computational pressure caused by the excessive concentration of computing tasks. In order to formulate the optimal topology reconfiguration strategy according to the specifics of voltage alerts, a differential hybrid Petri-net model with event-triggered strategy is constructed based on the cloud-edge collaborative architecture to characterize the logical relations of the solution process of the reconfiguration strategy. Considering the short time scale characteristic of preventive control, corresponding to the solution process described by the constructed model, an evaluation network based on graph convolutional neural network is proposed for the reachability discrimination of solutions to significantly reduce the number of candidate solutions, as well as a decision network based on multilayer perceptron is proposed for the selection of the optimal solution among the reachable solutions. Numerical tests are conducted on the modified IEEE 33-bus and IEEE 118-bus distribution systems to validate the effectiveness of the proposed method in dealing with voltage alert problems.

Reconfigurable optical crosshaul architecture for 6G radio access networks

The radio access network (RAN) architecture is undergoing a significant evolution to support the next-generation mobile networks and their emerging applications. To realize scalable and sustainable deployment and operations, RAN needs to consider the requirements of 6G and beyond wireless technologies such as ultra densification of cells, higher data rates, ubiquitous coverage, and new radio spectrum in the millimeter-wave band. This calls for a careful redesign of every aspect of RAN, including its crosshaul. The crosshaul is an important network segment in future RAN, capable of transporting diverse traffic types with varying stringent requirements within RAN. The crosshaul towards 6G is envisioned to be highly intelligent, reconfigurable, and adaptable to dynamic service requirements and network conditions. To this end, we propose a software defined network (SDN)-enabled reconfigurable optical crosshaul architecture (ROCA) that supports heterogeneous crosshaul transport technologies and dynamic functional splittings. ROCA enables efficient and intelligent control of the crosshaul data plane. The proposed architecture with a set of the next-generation RAN (NG-RAN) transport interfaces is evaluated using network models built on the ns-3 network simulator. Simulation results demonstrate the strengths and weaknesses of different crosshaul interfaces in agreement with the understanding of respective NG-RAN interfaces from the literature, which validates the modeling accuracy. We then demonstrate the reconfigurability of the architecture using a dynamic scenario with different reconfiguration strategies for meeting the user and network demands. The results indicate that ROCA serves as a scalable and flexible foundation for supporting high-capacity delay-stringent RAN that can be used in 6G and beyond wireless technologies.

Hybrid Adaptive Control for Tiltrotor Aircraft Flight Control Law Reconfiguration

Tiltrotor aircrafts have both fixed-wing control surfaces and helicopter rotors for attitude control. The redundancy of control surfaces provides the possibility for the control system to reconfigure the control law when actuator faults occur during flight. Possible actuator faults have been classified into two categories: predictable and unpredictable faults, and a different strategy has been adopted to deal with each kind of fault. Firstly, the predictable faults are handled by a multiple-model switching adaptive scheme. These kinds of faults are modeled, and their corresponding controllers are derived offline. Secondly, since the degree of drop in aerodynamic effectiveness cannot be predicted a priori, unpredictable faults are handled by a simple adaptive control scheme, to force the plant with faults to track the prescribed reference model. The presented methodology has been verified by nonlinear full-envelope flight simulation for both categories of actuator faults. The predictable fault is represented by the elevator floating. Elevator damage causing an aerodynamic effectiveness drop by 80% is chosen as the example of unpredictable fault. Both faults are simulated at the late stage of the tiltrotor conversion mode. Results show that the presented strategy of reconfiguration is able to detect the fault rapidly and stabilize the aircraft when a fault occurs, while the aircraft motion diverges without the reconfiguration scheme. The aircraft also presents a relatively good performance under controller reconfiguration with a well-tracked conversion path.

Dynamic multi‐agent dc‐bus reconfiguration in modular motor drives with a stacked polyphase bridge converter

AbstractA stacked polyphase bridge converter consists of multiple standard, three‐phase two‐level voltage source inverters connected in series to the same dc voltage source. The authors present a decentralised and dynamic dc‐bus reconfiguration strategy for this type of converter. The innovation of the proposed strategy lies in its ability to isolate or reactivate one of the inverters in the series connection online, even in motoring mode, enabling increased fault tolerance and an extended speed range. Both the required hardware alterations and the multi‐agent control strategy are addressed. Its major benefits compared to the state‐of‐the‐art are that only two additional active, unidirectional semiconductor switches are required per inverter, and that the control is based on local computations, local measurements and neighbour‐to‐neighbour communication only. Hence, the scalability and reliability of the hardware are extended towards the control. Simulations and experimental results on a 4 kW modular axial‐flux PMSM prove the feasibility of the concept, and validate that the dc‐bus can be reconfigured in 100 ms, without torque interruption.

Precise surface reorganization on iron incorporated cobalt oxides/phosphides using plasma technology for alkaline water/seawater electrolytes

Reasonable design of bifunctional catalysts with prominent catalytic activity and excellent stability is regarded as essential and valuable for alkaline seawater electrolysis. Herein, homogenous iron-incorporated cobalt oxides/phosphides nanowires (CoOx/Fe-CoP) were innovatively constructed with oxygen plasma oxidation-induced surface reconfiguration strategy. Benefiting from the abundant homogeneous interface, high intrinsic activity, and fast reaction kinetics, the CoOx/Fe-CoP demands only an ultra-low overpotential of 139 and 267 mV to achieve 100 mA/cm2 for hydrogen evolution reaction and oxygen evolution reaction in 1 M KOH, respectively. Furthermore, the assembled two-electrode configuration requires a cell voltage of 1.73/1.78 V at 100 mA/cm2 with outstanding durability for overall alkaline freshwater/seawater splitting, which is more remarkable than the mature Pt/C||RuO2 pair and many previously reported non-noble electrocatalysts. Hence, this research presents a promising approach to designing and fabricating efficient electrocatalysts by oxygen plasma surface reconstruction engineering toward alkaline freshwater and seawater electrolysis.

Design of an Improved Modular Multilevel Converter Reconfigurable Equalization Scheme Based on Difference of Voltage Variation

Abstract In order to solve the problem of lower available capacity and shorter cycle life due to the barrel effect of series-connected batteries, as well as the problem of pseudo-equalization caused by battery aging, this paper proposes a modified modular multilevel converter (MMC) reconfigurable equalization scheme with difference of voltage variation (DOVV) as the equalization variable. The equalization topology consists of an MMC circuit and a voltage regulator, which effectively solves the problems of low total available capacity, inefficient energy transfer, and slow equalization by reducing the number of switches and achieving independent control of the equalization and voltage regulator modules. A control strategy based on the Oxford aging dataset is proposed with DOVV as the equalization variable, and a fuzzy logic control algorithm is introduced according to the distribution characteristics of DOVV data. This equalization control strategy overcomes the pseudo-equalization phenomenon due to battery aging. The simulation results show that compared with the traditional DC–DC energy transfer equalization topology, the energy transfer efficiency of the proposed equalization topology is improved by 62.15% and the equalization time is reduced by about 16.36%, and the pseudo-equalization phenomenon caused by the aging of the battery pack during the equalization process is well overcome. The feasibility of the proposed equalization scheme is verified.

Switch Short-Circuit Fault-Tolerant Control of Five-Phase Open-Winding Motor Drive With a Floating Capacitor

This paper proposes a switch short-circuit (SC) fault-tolerant control (FTC) method for the open-winding topology with a floating capacitor, where the main inverter is supplied by a DC source, and the floating inverter is merely supplied by a capacitor. The SC faults are divided into two types and analyzed in detail. For the fault of Type I, the proposed reconfiguration strategy can isolate the faulty device to ensure stable operation. For the fault of Type II, the control of zero-axis voltage in the topology is introduced to replace the control of the faulty bridge. Besides, the fault-tolerant power smoothing strategy is applied to suppress the low-frequency ripples of the floating capacitor voltage and input current from the DC source, which further improves the torque quality. Compared with the previous method, the proposed FTC method does not require additional hardware costs to convert the short-circuit to an open-circuit. Meanwhile, the motor can still give out rated torque even after the fault. The performance of the proposed FTC method is verified experimentally in an open-winding five-phase induction machine system.

Pavement PV array reconfiguration strategy based on traveling salesman problem

The dynamic random vehicle shadow caused by high-speed vehicles on the pavement PV arrays not only easily induces the series and parallel mismatch of the PV array on the pavement, resulting in power loss, but also leads to the complex fast-changing multi-peak phenomenon of its output characteristics, which increases the difficulty of the maximum power point tracking control and intensifies the power loss. To address this issue, this paper proposes a novel dynamic reconfiguration strategy for pavement PV arrays based on the traveling salesman problem (TSP). In the proposed method, the optimal pavement PV array reconfiguration is transformed into a traveling salesman problem. Through comparative experiments, the simulated annealing (SA) algorithm is verified to be able to effectively solve the reconfiguration problem based on TSP. Finally, the simulation and experiment results show that the proposed reconfiguration method can reduce the number of local maximum power points, improve the global maximum power of pavement PV array, and effectively improve the power generation efficiency of the PV system.

Adaptive interference mitigation space‐time array reconfiguration by joint selection of antenna and delay tap

AbstractSpace‐time adaptive processing (STAP) array has found extensive use in the global navigation satellite system for interference suppression. Nevertheless, the conventional space‐time array necessitates multiple antennas and time delay taps, resulting in a heavy burden on both hardware and computation resources. Thus, lowering the cost and complexity of STAP becomes a considerable problem demanding prompt solutions. This work designs a space‐time array reconfiguration scheme based on the joint selection strategy of the antenna and delay tap to address this problem. The reconstructed array can induce a high signal to interference plus noise power ratio (SINR) when using fewer antennas and delay taps. The space‐time correlation coefficient (STCC) is first presented to manifest the influence of reconfiguration on output SINR. Then, we formulate the space‐time array reconfiguration mathematical model, aiming to minimise STCC. Two reconfiguration methods are provided to solve the optimal array configuration of antennas and delay taps that can reach the minimum STCC and maximum SINR. The optimal antenna‐delay tap pairs are finally selected to comprise the reconstructed array. Substantial simulation experiments verify that the presented scheme and strategy are effective and reliable in space‐time array reconfiguration.