Search Results (2,794)

Network Digital Twins (NDTs) require accurate, structured, and timely data from heterogeneous communication networks. However, many existing approaches assume that this information is already available and do not address the operational path needed to convert raw observations into deployable twin artifacts. This paper presents DANA, a lifecycle-aware data acquisition and transformation system for dedicated network devices and general-purpose systems hosting virtualized or containerized functions. Its key technical contribution is a unified workflow that coordinates centralized and distributed acquisition through a common, state-aware normalization layer. Each observation is associated with source, temporal, scenario, and lifecycle metadata, enabling the system to preserve the structural baseline used to construct the twin while processing runtime monitoring information separately. The normalized representation is decoupled from deployment-specific descriptor generation, while data and control exchanges follow a publish/subscribe communication model. The system is evaluated in two complementary controlled laboratory scenarios. The centralized workflow demonstrates accurate topology reconstruction and high agreement in network reachability, whereas the distributed workflow validates the complete path from host-level acquisition and normalization to descriptor generation and twin instantiation. Complementary local microbenchmarks characterize MQTT transport, fixed-load resource use, and stop/recovery event propagation to a test consumer while preserving the structural baseline. These results support the feasibility of the proposed workflow in the studied environments; large-scale operation and full synchronization of deployed NDTs require further experimental validation. Full article

High photovoltaic (PV) penetration can increase active power losses and cause steady-state voltage violations in distribution networks. This paper develops an integrated day-ahead and intraday voltage/var control (VVC) framework that coordinates discrete and continuously controllable devices while explicitly checking the residual of the branch-flow second-order cone relaxation (SOCR). A common 15 min time grid is adopted: on-load tap changer (OLTC) and capacitor-bank (CB) decisions are constrained to remain unchanged within each hourly block, whereas static var compensators (SVCs) and PV inverters are scheduled every 15 min. The day-ahead stage minimizes network losses subject to switching limits and determines the discrete-device schedules. The intraday stage fixes these schedules and uses the normal-boundary intersection (NBI) method to generate trade-off solutions between average voltage deviation and active power loss. A sequential difference-of-convex programming (DCP) correction is activated when the SOCR residual exceeds the prescribed tolerance. For two representative 15 min intervals of the modified balanced single-phase IEEE 123-bus feeder, the maximum residuals of all nine reported Pareto solutions are below 4.805 × 10⁻⁵, and the most demanding voltage deviation subproblem converges after 12 DCP iterations. The results demonstrate the feasibility of the proposed deterministic coordination framework; forecast-error robustness, broader method comparisons, and field validation remain subjects for further study. Full article

Accurate prediction and inversion of time-dependent gap deformation between a passenger aircraft door and its frame remain difficult under slowly varying pressurization because the response is governed by coupled geometry, lock restraint, and nonlinear contact. This study develops a digital-twin-driven inversion framework for door–frame gap deformation. A physics-based parametric twin is established using feature associations and a unified assembly datum, and the outer skin, stiffeners, load-bearing frame, inner panel, locks, and door frame are represented in a nonlinear quasi-static finite-element model. Geometric nonlinearity and a separable door–frame contact are retained so that load-dependent opening, local slip, and constraint effects can be captured. A full-scale test platform with binocular vision provides three-directional relative-displacement measurements. The numerical model is updated through equivalent-stiffness correction, local nodal adjustment, and global scaling, with physical restrictions imposed on the adjustable region and correction amplitudes to avoid unconstrained point-wise fitting; corrected simulation and experimental data are then fused for surrogate training. An improved Gaussian process regression model uses the normalized pressure level, spatial coordinates of the registered key-point pairs, and displacement-direction encoding as inputs and the corresponding fused directional gap displacement as the output; a squared-exponential kernel and input-dependent noise model represent nonlinear response and uncertainty. Under an identical within-profile training–validation partition, the reported GPR implementation yields lower aggregate error than the corresponding RBF-NN and random-forest benchmark runs, with a root-mean-square error of 0.21, a mean relative error of 2.8%, and a coefficient of determination of 0.985. These metrics quantify interpolation within the calibrated slowly varying quasi-static loading domain rather than validated extrapolation to an independent unseen load history. The framework provides a mechanism-consistent route for virtual–physical updating and surrogate-based inversion of aircraft door–frame gap states. Full article

Blast-induced ground vibration is traditionally predicted using empirical scaled-distance equations or numerical simulations driven by simplified analytical loading functions. Although dynamic finite element modeling has significantly advanced the understanding of stress-wave propagation, existing approaches remain unable to reproduce the complete seismic response of actual production blasting because the true blast source is generally unknown and is therefore replaced by simplified pressure–time functions. Consequently, a field-calibrated physics-informed Digital Twin framework for production blasting remains insufficiently established. This study presents a PI-DDT framework for production blasting based on field-derived seismic source reconstruction. The proposed methodology consists of two complementary innovations. First, the three-component near-field pilot-blast record was analyzed through deconvolution-based inverse wave propagation, and the transverse, longitudinal, and vertical components were independently deconvolved to reconstruct three orthogonal equivalent single-hole seismic source histories at the pilot blast hole. Second, the three reconstructed source histories were incorporated into the PLAXIS 3D dynamic finite element model through component-specific dynamic multiplier functions together with the actual production-blast geometry, blast-hole coordinates, electronic initiation sequence, site-specific rock-mass properties, and attenuation characteristics to establish a field-calibrated PI-DDT framework for a full-scale production blast. The proposed framework was applied to a full-scale production blast comprising 83 blast holes in an operating open-pit mine. Model performance was evaluated through a multi-domain performance assessment including PPV, amplitude-envelope development, frequency-spectrum agreement, and cumulative-energy evolution. The simulated responses showed practically meaningful agreement with field measurements across multiple monitoring locations, with a median component PPV error of 11.8%, a mean three-dimensional resultant PPV error of 14.2%, a mean resultant spectral similarity of 84.0%, and a mean three-dimensional cumulative-energy MAE of 4.7%. Unlike conventional blasting simulations that rely on simplified analytical loading functions, the proposed methodology reconstructs a field-derived equivalent seismic source signature and integrates it directly into a physics-based numerical model. The principal scientific contribution of the study lies in the field-calibrated integration of equivalent seismic source reconstruction, actual production-blast geometry and initiation timing, three-dimensional dynamic FEM, and multi-domain model-performance evaluation within a unified physics-informed framework. The developed framework provides a physics-based computational foundation for blast-design evaluation, vibration-control planning, digital mining applications, and future AI-assisted blast-design optimization and adaptive vibration-control workflows. Full article

High shares of wind and solar power make generation outputs strongly random. Traditional stochastic optimal power flow (SOPF) also lacks power–carbon coordination. Low-carbon constraints are often disconnected from operational scheduling. To address these issues, this paper proposes an SOPF method that includes an optimal carbon-trading mechanism. First, Monte Carlo simulation and K-means clustering generate typical renewable-generation scenarios. Each scenario is assigned a probability. Scenario reduction preserves the statistical features of uncertainty while lowering computational cost. Second, a full-link carbon-footprint index system is built for the generation, grid, and load sides. It covers carbon-emission measurement, efficiency constraints, and low-carbon constraints. It describes the spatial distribution and time-series transmission of carbon flow. Third, a carbon-trading scheme-selection framework is proposed. It combines a Nash equilibrium game with AISM hierarchical topology analysis. It balances the revenues of generators, the grid, and users, and it follows the hierarchical transmission of carbon indicators. The optimal scheme is selected and the system carbon-reduction benchmark is set. Finally, a multi-objective model is built. It minimizes generation and transmission cost, minimizes carbon-emission cost, and maximizes the carbon-reduction contribution rate of renewable consumption. The equal incremental rate criterion is used for iteration. Case studies on an improved IEEE 33-bus network verify the method. The method links carbon-trading rules with grid scheduling. It improves the accuracy and engineering value of low-carbon regulation. Full article

An energy router (ER), featuring flexible multi-port access, bidirectional power regulation, and cross-regional energy exchange, provides versatile control capabilities for fault isolation, critical-load supply, and post-disaster restoration in distribution networks under extreme-event scenarios. However, existing studies have not fully exploited the dynamic relocation and flexible power-transfer capabilities of ER ports when post-disaster network fragmentation and multiple islands coexist; moreover, existing distribution-network resilience optimization methods depend on assumptions about the extent of extreme-event damage. To address these issues, this paper proposes a coordinated pre-event defense and post-event restoration method for enhancing distribution network resilience under extreme-event scenarios while accounting for ER flexible interconnection capabilities. First, a virtual node-based equivalent model of a multi-port ER-integrated distribution network is established; it preserves radial operation while representing ER port capacities and internal power balance. Second, an information-gap decision theory (IGDT)-inspired scenario formulation is introduced in the pre-event defense stage, where cumulative damaged-line resistance serves as a simplified damage-severity proxy for the test system; a coordinated line hardening and ER defense model is then developed, and the defense resource allocation under a given annualized pre-event investment limit (the defense budget) is determined through siting enumeration and a sequential search over the conservativeness coefficient β. For the post-event restoration stage, a multi-period model coordinating sequential line repair and dynamic ER port relocation is formulated, and a superset topology transforms time-varying network reconfiguration into the sequential switching of virtual-branch connection states in a static expanded network. Case-study results demonstrate that the proposed method improves the ability of a distribution network to withstand extreme-event scenarios under a limited budget, reduces the total weighted energy not supplied over the restoration horizon, and improves both critical-load restoration efficiency and distributed generation utilization. Relative to fixed ER ports, dynamic relocation primarily improves critical-load prioritization rather than the total energy supplied. The proposed coordinated pre-event defense and post-event restoration framework provides a theoretical basis for resilience planning and the post-disaster dynamic restoration of ER-integrated distribution networks. Full article

With the global energy transition and the increasing use of renewable energy, coal-fired power plants are shifting from baseload generation toward flexible operation for load following and frequency regulation. However, low-load operation can destabilize boiler combustion, accelerate equipment wear, and complicate emissions control. Thermochemical energy storage offers high storage density, low heat loss during storage, and a wide operating temperature range. It may therefore support the flexible operation of coal-fired power plants. This narrative review compares six thermochemical energy storage systems: CaO/CaCO₃, CaO/Ca(OH)₂, ammonia decomposition and synthesis, metal hydrides, metal oxide redox systems, and methane dry reforming. The comparison considers reaction temperature, storage density, material cost, cyclic stability, safety, and compatibility with coal-fired power plants. Based on this qualitative comparison, CaO/CaCO₃ appears to offer relatively favorable compatibility because of its low-cost raw materials, relatively high storage density, good temperature matching with high-temperature flue gas, and potential integration with CO₂ capture. Three integration pathways are further reviewed: solar-driven CSP–CaL, calcium-looping carbon capture with sorbent storage, and flue-gas-driven calcination with carbonation-based flue-gas reheating. The first two pathways have received more extensive modeling and experimental investigation. The flue-gas-driven pathway remains mainly at the conceptual and component-validation stages. Its main constraints include CaO deactivation, flue-gas impurities, reactor scale-up, and coordination with variable boiler operation. Overall, the reviewed evidence suggests that CaO/CaCO₃ may offer a favorable temperature and process match for integration with coal-fired power plants. However, the flue-gas-driven pathway is not yet ready for plant-scale application. Future research should focus on long-term testing under real flue gas, reactor scale-up, dynamic reactor–boiler demonstrations, and consistent techno-economic and life-cycle assessments. Full article

The increasing demand for flexible, high-precision, and low-damage manufacturing is driving industrial robotic grippers toward adaptive systems with compliant interaction, force regulation, and intelligent decision-making capabilities. However, their industrial deployment remains limited by three major challenges: the trade-off between structural compliance and load-bearing capability, the insufficient coordination between sensing performance and closed-loop force control, and the limited generalization and safety validation of learning-based methods. This review presents an engineering-oriented analysis of adaptive robotic grippers based on three paradigms: structural compliance, active compliance, and learning-enabled grasping. The design principles, performance characteristics, and application limitations of compliant mechanisms, variable stiffness structures, carbon fiber composites, embedded sensing, force control, data-driven methods, reinforcement learning, and model–data fusion are discussed. A comparative framework is established according to the adaptation mechanisms, key parameters, performance boundaries, and industrial applications. The analysis shows that representative underactuated grippers typically achieve 3–19 degrees of freedom, grasping success rates of 90–98%, and load capacities of approximately 10–50 N, but remain limited in force regulation. Actively compliant grippers achieve force errors of 0.1–1 N, position errors of 0.05–0.5 mm, and control frequencies of 500 Hz–1 kHz, while learning-enabled methods require 10²–10⁴ samples for compensation and 10⁵–10⁶ interactions for reinforcement learning. The model–data fusion provides a practical balance between adaptability, interpretability, and safety. Future adaptive grippers will evolve toward integrated structure, sensing, learning, and control architectures with enhanced reliability and industrial applicability. Full article

To address the unclear classification of evaluation targets, insufficient characterization of inter-entity interactions, and the lack of a systematic summary of indicator applications in new power systems under source–grid–load–storage coordination, this paper reviews the classification and application of power system security indicators. Taking the evaluation targets of security indicators as the primary perspective, a classification framework is established by considering source-side, grid-side, load-side, and storage-side entities, as well as the interactions among them. The resulting framework covers entity-specific indicators for the source, grid, load, and storage sides, as well as interaction-oriented indicators for source–grid, source–load, source–storage, grid–load, grid–storage, load–storage, and multi-entity coordination. The characterization contents, applicability relationships, and application modes of different indicator categories are further analyzed. Typical applications of security indicators in optimization decision-making and security assessment are summarized, and a security indicator selection and application process incorporating scenario- and model-applicability assessment is proposed. Future research directions are also discussed, with an emphasis on extending indicator applications to complex operating scenarios, improving model adaptability, and advancing quantitative characterization and standardized application. The study provides a reference for the rational selection, standardized application, and further development of security indicator frameworks under source–grid–load–storage coordination. Full article

With the increasing integration of distributed generation, energy storage, and flexible loads, active distribution networks have gained multiple fault-recovery options, including network reconfiguration, islanded operation, and coordinated source–load regulation. However, existing studies often lack an effective link between system-level restoration decisions and resource-level execution. To address this issue, this paper proposes a two-layer collaborative optimization method for multi-period fault recovery with fast decomposition. The upper layer develops a multi-period restoration model that jointly optimizes network reconfiguration, load restoration targets, and fault repair sequences, with the objectives of minimizing load loss and recovery cost while maximizing continuous power-supply duration. The model incorporates load priorities, switch operations, distributed generation, energy-storage states, flexible-load response, main-grid support, and inter-period coupling constraints. Based on the restoration targets generated by the upper layer, the lower layer applies a fast sort-and-fill decomposition strategy to allocate regulation demands among photovoltaic generation, wind power, energy storage systems, flexible loads, and main-grid support, thereby forming a closed-loop coordination mechanism between restoration planning and resource execution. The proposed method is validated on a modified IEEE 33-bus active distribution network under multi-period fault scenarios. Results show that the load restoration rate is 88.78% in Period 1 and reaches 100% from Period 2 onward. Compared with static restoration, unserved energy decreases from 4.6896 MWh to 0.3113 MWh, while restored energy increases from 8.2505 MWh to 12.6288 MWh. Over 1000 randomized feasible operating points, the maximum absolute objective gap between the proposed sort-and-fill procedure and direct LP re-optimization is 7.55 × 10⁻¹⁴%, and the maximum power-balance error is 2.73 × 10⁻¹² kW. These results demonstrate that the proposed method improves restoration effectiveness while reproducing the exact lower-layer LP solution within numerical precision. Full article

We report on the synthesis of a new CaAlO₂F phase with a perovskite-type structure, which was formed as a third phase in the CaFap–alumina composite during the calcination of a mixture of Ca₁₀(PO₄)₆F₂ and Al(OH)₃. The atomic coordinates, lattice constant, and space symmetry group of the CaAlO₂F phase were determined by the XRD method. Next, the chemical composition and mechanical properties of the CaFap–alumina composite bioceramics were investigated. The material was found to exhibit high porosity, with pore diameters ranging from 100 to 1000 μm. The measured mean values of microhardness and Young’s modulus were 6.1 ± 1.0 GPa and 103 ± 8 GPa, respectively. The new CaAlO₂F phase constituting the bioceramics exhibited a significantly higher nanohardness of 11.8 ± 1.5 GPa and Young’s modulus of 137 ± 9 GPa, which indicates that this phase can significantly improve the mechanical properties of CaFap–alumina bioceramics. The resulting fluorapatite-based biocomposite can pave the way for advanced medical ceramics as a material for load-bearing implants. Full article

Saudi Arabia is expanding renewable energy and grid-scale storage as part of the modernization of its power sector. Solar and wind power can reduce dependence on fossil fuel generation, but their variable output adds operational challenges related to ramping, reserve planning, voltage and frequency control, renewable curtailment, and peak demand management. This paper reviews how energy storage can support renewable energy integration in the Saudi power grid, with attention to reliability, flexibility, storage technologies, smart grid readiness, policy and regulation, techno-economic considerations, and local operating conditions. A structured narrative review was conducted using international peer-reviewed literature together with authoritative Saudi technical, regulatory, policy, and project sources. The review indicates that storage should be evaluated according to the grid service delivered, rather than installed capacity alone. Battery energy storage systems can provide fast grid support services, including frequency response, voltage support, renewable smoothing, reserve support, ramp-rate control, and short-duration energy shifting. Longer-duration options, such as flow batteries, thermal storage, compressed air storage, gravity storage, and hydrogen-linked pathways, may also be useful for bulk shifting and wider balancing needs when technical, economic, and site conditions are suitable. However, storage is not a direct substitute for grid reinforcement, firm generation, demand response, forecasting, or smart grid control. Its value depends on response time, discharge duration, usable energy capacity, converter capability, state-of-charge management, thermal management, degradation, dispatch rules, and cost of service delivery. The review identifies several challenges relevant to Saudi Arabia, including high ambient temperature, dust and soiling, cooling-driven demand, battery degradation, storage sizing and siting, forecasting accuracy, market rules, cybersecurity, and performance verification. Future research should give greater attention to hot-climate battery performance, renewable and load forecasting, optimal siting, storage service valuation, forecasting-linked dispatch, hybrid storage options, and coordination between storage systems and smart grid infrastructure. Full article

Rural residential buildings in China’s Central Plains region suffer from poor envelope thermal performance, resulting in severe thermal discomfort and excessive energy consumption for both winter heating and summer cooling. This study presents a systematic three-in-one envelope retrofit strategy (roof, exterior walls, and windows, with supplementary door replacement) tailored to the region’s cold climate zone (GB 50176-2016, Zone IIB; HDD18 = 2309 °C·d, CDD26 = 131 °C·d), which experiences hot summers and cold winters and thus requires both effective winter insulation and summer heat protection, utilizing cost-effective materials suitable for rural construction. A typical brick-concrete rural residence in Anyang was selected as the case study building. Field measurements of indoor thermal conditions were conducted over 72 h in winter to characterize baseline performance. An Ecotect simulation model was developed and calibrated against measured data using actual hourly meteorological observations from the Anyang National Meteorological Station for the monitored period; the CSWD Typical Meteorological Year (TMY) file was used for the annual simulation. To address concerns regarding discontinued software, key annual load results were cross-validated against an independent EnergyPlus v22.2 model using identical geometry and envelope inputs, yielding agreement within 5%. The proposed retrofit scheme retains the existing 240 mm solid brick walls, adds external insulation consisting of 100 mm EPS panels for walls and 50 mm XPS panels installed at ceiling level within the attic (without disturbing the existing asbestos-cement roof sheeting, in accordance with strict asbestos-handling protocols) for roofs, and replaces single-glazed windows with 6 + 12A + 6 insulated hollow glass units. The results demonstrate that the optimized envelope significantly reduces overall heat transfer coefficients: wall U-value decreases from 1.79 to 0.32 W/(m²·K), roof U-value from 2.46 to 0.48 W/(m²·K), and window U-value from 6.40 to 2.40 W/(m²·K). The passive adaptability index (PAI)—the annual proportion of free-running hours within the fixed 18–28 °C screening band specified in ^{Table 4}.3.1 of GB/T 50785-2012—improves from 0.41 to 0.68, and annual heating and cooling energy consumption is reduced by 50.4% (49.6% when the supplementary door replacement is excluded; (123 − 62)/123 = 49.6%). Under this fixed-band screening criterion, indoor operative temperature lies within the band for 68% of annual hours, compared with 41% in the baseline; these figures are fixed-temperature-range screening results rather than a formal adaptive-comfort evaluation (^{Section 3.3} and ^{Section 6.3}). A Glaser method condensation analysis confirms no interstitial condensation risk in the externally insulated EPS wall assembly. This study provides validated, region-specific technical parameters and demonstrates that a coordinated three-component envelope retrofit can achieve over 50% energy savings while substantially improving indoor thermal conditions as measured by the fixed 18–28 °C screening band in rural Central Plains buildings; a formal adaptive thermal comfort evaluation was not conducted and is identified as future work (^{Section 3.3} and ^{Section 6.3}). The material-cost-based simple payback is approximately 5.5 years (CNY 19,500 ÷ CNY 3550/year); including estimated rural labor and scaffolding costs (CNY 4000), the full project payback is approximately 6.6 years (CNY 23,500 ÷ CNY 3550/year). The findings offer practical guidance for large-scale rural building energy retrofitting programs in cold climate zones of China with transitional characteristics. Full article

With the increasing proportion of flexible resources such as distributed generation, energy storage and demand response in new power systems, load aggregators, as an important subject connecting users and the market, face the challenges of complex load types, large differences in response capabilities, and high peaking costs. Therefore, this paper proposes a coordinated optimization strategy of load and electricity consumption considering aggregator load demand and peak load regulation incentive. Firstly, based on the operating characteristics of load equipment in multiple scenarios, the aggregator load is divided into three categories: energy storage type, elastic electrical equipment and inelastic electrical equipment, and the corresponding electricity cost model is established. Combined with utility theory and user subjective perception, a residential and industrial electricity comfort model is constructed. Secondly, a price-elasticity-based load potential assessment method is developed to quantify response envelopes under time-of-use tariffs, and a bi-level optimization model considering peak load regulation incentives is constructed. Next, in order to solve the bi-level non-convex optimization problem efficiently, a reinforcement learning solution framework based on a multi-agent deep deterministic policy gradient is proposed. The aggregator and user groups are modeled as collaborative agents respectively, and the global optimal strategy is realized by centralized training and decentralized execution. Finally, simulation results show that the proposed strategy can effectively guide the load from the peak period to the trough period, significantly improve the peak load shifting effect, improve the users’ electricity satisfaction, and reduce demand-side response cost. Full article

Time-interleaved high-speed data acquisition (HS-DAQ) systems based on three-dimensional network-on-chip (3D NoC) architectures require efficient transmission of multi-channel sampled data. However, existing general-purpose NoC architectures are not well suited for the deterministic multi-source aggregation communication pattern of HS-DAQ systems, which may result in increased long-distance transmission overhead and localized traffic congestion. To address these issues, this paper proposes a 3D aggregation backbone network-on-chip architecture (3D AB-NoC) for HS-DAQ systems. This architecture is based on a 3D Mesh structure and enables the rapid transmission of long-distance aggregated data by establishing coarse-grained aggregation backbone subnets between defined aggregation routing nodes. Furthermore, a Backbone-Boosted XYZ (BB-XYZ) routing algorithm is proposed, which selects the next hop based on the remaining transmission distance of both the basic mesh path and the backbone path, thereby achieving coordinated routing for both local transmission and long-distance aggregation. Simulation results based on the Access Noxim platform demonstrate that the 3D AB-NoC maintains stable basic communication performance under general communication scenarios. In HS-DAQ communication scenarios, the proposed architecture reduces average latency by up to approximately 44%, improves throughput by approximately 29.3%, and significantly suppresses the growth of maximum latency under high-load conditions. Full article