Search Results (854)

In recent years, traditional cast-in-place concrete construction for pre-drilling engineering in unconventional natural gas fields has generated large amounts of waste concrete, consumed significant resources, and prolonged project schedules. To address these issues, this study proposes a prefabricated pavement slab system as a green and low-carbon alternative. Based on vehicle load surveys at shale-gas well sites in southwestern China, three loading conditions (design, overload, and ultimate axle loads) were defined. Theoretical calculations were then performed for reinforcement design, crack-width control, and local bearing capacity verification. A full-scale precast slab (3000 × 1495 × 150 mm) was fabricated and tested under static monotonic loading to measure deflection, crack development, steel strain, and concrete strain until failure. Separately, a three-dimensional finite element model of a four-panel pavement system (including a mortar-leveling layer and soil subgrade) was developed in ANSYS to simulate static and, preliminarily, moving loads. The experimental slab reached an ultimate load of about 365 kN (based on a single specimen, and thus not statistically representative), with ductile bending failure and crack/deflection patterns typical of reinforced concrete. The numerical model reproduced the cracking load and peak capacity with deviations below 17% from the test data, though post-cracking deflections were underestimated. Overall, the results demonstrate that the proposed prefabricated system is structurally feasible for heavy-duty drilling sites. It enables factory production, rapid on-site assembly, and reuse after dismantling, thereby reducing construction waste, shortening timelines, and supporting energy conservation and emission-reduction goals in the context of China’s green building policies. Full article

Cloud data sharing allows users to outsource data storage and management to external servers, but it also raises privacy concerns when data must remain encrypted while still supporting efficient search and fine-grained access control. Attribute-based encryption with keyword search (ABE-EKS) addresses this problem by combining searchable encryption with attribute-based access policies. However, existing schemes often focus on separate aspects such as expressive search, online/offline computation, revocation, or policy protection, while controlled trapdoor delegation and inequality-based keyword predicates are less commonly considered together in an implementation-oriented Type-3 pairing setting. This paper revisits the ABE-EKS framework of Yang et al. and adapts it to the Type-3 pairing setting. The construction follows the main structure of Yang et al.’s ABE-EKS scheme, but places the group elements in the appropriate source groups for asymmetric pairings. It further supports expressive access-control and keyword-search policies, Boolean keyword predicates, inequality comparisons, and trapdoor key delegation. We also analyse its security under the honest-but-curious cloud model and implement the scheme using the Apache Milagro Cryptographic Library (AMCL). Experimental results on the Enron Email dataset demonstrate the feasibility of the proposed construction for outsourced encrypted data-sharing scenarios. Full article

Low Earth orbit (LEO) mega-constellations demand scalable routing that survives time-varying topologies, constrained onboard resources, and dynamic traffic. Deterministic shortest-path routing guarantees optimal paths but adapts poorly to real-time loads; distributed deep reinforcement learning (DRL) can introduce loops and inconsistent end-to-end decisions. This paper fuses deterministic inter-domain planning with DRL-based intra-domain forwarding in a single hierarchical framework. An evolutionary greedy algorithm partitions the constellation into compact domains. Dijkstra’s algorithm then computes backbone paths on the domain-level graph. Inside each domain, a context-enhanced Per-Action Dueling Double Deep Q-Network encodes individual neighbors through a weight-shared encoder and summarizes the valid-neighbor set via masked mean pooling. This design lets the policy compare a candidate against the current alternative set without injecting input-order bias. Local one- and two-hop topological features drive decentralized inference. A greedy–beam–Dijkstra fallback ladder guarantees reachability whenever the subgraph stays connected. On a 1584-satellite Starlink Gen1-1 topology, all 21 domain sizes and six inter-domain strategies reach 100% of test pairs; the best average hop count sits at 1.16× the global Dijkstra benchmark. Under an identical 52-dimensional state and training pipeline on 1000 held-out source–destination pairs, Context Per-Action uses 75.8% fewer parameters than a flat multilayer perceptron (MLP), lifts greedy success from 74.6% to 83.5%, and lifts greedy-plus-beam success from 88.3% to 94.5% (means over three independent training seeds). Centralized load-aware routing under dynamic traffic cuts high-load packet loss from 34–73% to 0–9.5% in the adopted flow-level model and preserves 99.2% reachability despite 30% link failures. Zero-shot transfer from ideal Walker topologies to real two-line element (TLE) snapshots and purely local load adaptation remain open; multi-snapshot training or online adaptation is the necessary next step. Full article

To resolve thermodynamic uncertainties in global gas–particle partitioning and persistent organic pollutant transport, this work integrates polycyclic aromatic hydrocarbons (PAHs) into the CHASER V4.0 chemistry–climate model, presenting the first global online simulations of naphthalene (NAP), phenanthrene (PHE), pyrene (PYR), and benzo[a]pyrene (BaP) within this framework to study their fate in the atmosphere. Soot adsorption (K_SA(T)) is coupled with organic matter absorption (K_OA(T)) under an extended Dachs–Eisenreich dual-mode scheme. The coupled model was evaluated at urban, background, and Arctic stations, satisfactorily capturing the broad global spatial gradients (pooled spatial R = 0.78 on a log₁₀ scale; spatial FAC2 = 80% for BaP excluding severe sub-grid hotspots) and seasonal cycles (R = 0.62–0.93). The K_SA(T) scheme rectifies the under-prediction of the particle-bound fraction (φ) in cold high-latitude regions (increasing polar φBaP by up to ~0.6), inherent in the baseline K_OA(T) scheme. Sensitivity tests show that elevated elemental carbon (f_EC) enhances soot adsorption and particle-phase shielding against oxidation, extending the mean lifetime of BaP to 1.72 days (compared to 0.57–0.72 days for lighter congeners) and sustaining transoceanic outflow. Overall, this framework provides an essential tool for assessing transboundary toxicant transport, climate-sensitive health risks, and pollution mitigation policies. Full article

Low-impact development (LID) and nonpoint-source pollution reduction facilities are increasingly expected to function as long-term components of urban infrastructure rather than as isolated environmental features. Their sustainability depends not only on technical design but also on institutional review, construction assurance, operation and maintenance, performance verification, information continuity, and adaptive policy learning. This study comparatively examines the content and structure of three major South Korean guidance documents issued in 2013, 2016, and 2020: the national LID Technology-Element Guideline, Seoul’s Guidance for the LID Prior-Consultation System, and the national Manual for the Installation and Management/Operation of Nonpoint-Source Pollution Reduction Facilities. A directed qualitative content analysis was conducted using seven literature-informed lifecycle-governance dimensions covering problem framing, planning and approval, facility selection and sizing, installation and construction control, operation and maintenance, monitoring and performance verification, and adaptive feedback. Documentary provisions were assessed using a four-level ordinal scale ranging from absent to strong coverage. The analysis indicates a functional expansion of governance provisions across the three documents, from LID principles and technology selection to pre-permit review, quantitative runoff-management requirements, installation guidance, operation and maintenance, monitoring, and performance testing. However, the documents collectively show discontinuities between approval and construction verification, construction and long-term operation, maintenance and compliance, monitoring and policy learning, and lifecycle information management. In response, this study proposes a six-stage lifecycle-governance framework linking planning, pre-permit verification, construction commissioning, asset registration, risk-based maintenance and monitoring, and adaptive policy learning. The framework is presented as an analytical and normative synthesis rather than an empirically validated governance model. Because the study is limited to documentary analysis, the findings do not demonstrate actual implementation effectiveness, regulatory compliance, maintenance quality, or environmental performance and should be validated through future empirical and comparative research. Full article

This article examines the Carbon Border Adjustment Mechanism (CBAM) as a regulatory instrument of the European Union, situated at the intersection of international trade law, customs law and environmental protection. The primary objective of the study is to assess the legal nature of the CBAM, evaluate its compatibility with World Trade Organisation (WTO) law and analyse its implications for sustainable global trade governance and climate policy. Particular attention is paid to Articles I, III and XX of the GATT, as well as relevant WTO case law, including the cases of United States—Gasoline, United States—Shrimp, European Communities—Asbestos and Brazil—Retreaded Tyres. The study further examines the procedural transformation of customs authorities, particularly in relation to the verification of emissions, the burden of proof and administrative enforcement. The article also assesses the environmental effectiveness of the CBAM in preventing carbon leakage and in enforcing higher environmental standards in third countries, addressing the legal and economic issues of discrimination, proportionality, administrative complexity and potential impact on developing economies. The research is based on doctrinal legal analysis, comparative legal methodology and a review of relevant international and European legal sources, including WTO case law and Regulation (EU) 2023/956. The authors demonstrate that the CBAM represents a hybrid regulatory mechanism combining elements of environmental taxation, regulatory charges and trade policy instruments implemented through customs procedures. The originality of the article lies in its integrated and comprehensive analysis of the CBAM from the perspective of customs law, international trade law and environmental regulation with a focus on sustainability. In contrast to existing studies focusing primarily on trade or climate aspects, the article highlights the evolving regulatory role of customs authorities in the framework of European Union climate governance. The findings suggest that the CBAM is generally compatible with WTO law, provided that it is implemented in a transparent, proportionate, flexible and non-discriminatory manner. The authors conclude that the CBAM can become an important model for the future development of sustainable international economic regulation and climate-related trade governance. Full article

Global biodiversity policy increasingly depends on community-led conservation, yet the comparative evidence base contains little from South Asia’s frontier regions. This article asks how a long-running grassroots organisation in a politically and ecologically marginal region combined community mobilisation, vernacular knowledge, scientific evidence, and engagement with public institutions in pursuing conservation outcomes, and which features of that process may be relevant beyond Northeast India. Four campaigns of Nature’s Beckon, founded in Dhubri, Assam, in 1982, are compared as distinct types of intervention: species-led protected-area mobilisation at Chakrashila; landscape-scale conservation against extractive pressure at Dihing Patkai; species research with public ecological education; and community-managed institution-building. The available evidence indicates a documented and substantial, though not exclusive, role in campaigns associated with the notification of two protected areas whose current notified areas total approximately 279.83 km². Advocacy alone does not adequately explain these outcomes: where a formal government decision was required, sustained organisational capacity became consequential only when it coincided with a favourable political and administrative opening. Measured against four design features associated with successful community-based conservation, the model corresponds strongly to capacity-building investment and external linkage, in qualified form to equitable benefit-sharing, and only partly to tenure security. The article develops an ecology of the margins framework and specifies which elements appear transferable and which do not. Full article

Rapid urbanization has led to habitat fragmentation in peri-urban areas, continuously eroding the ecological foundation of sustainable food systems in urban–rural transition zones and posing a real threat to regional food security. Against the backdrop of urbanization disturbances, traditional nature-based solutions have limitations in addressing socioecological nonlinear responses, whereas digital tools offer new governance pathways for enhancing food system resilience. To elucidate the intrinsic mechanisms through which digital technology empowers the resilience of peri-urban food systems, this study, which is grounded in ecological wisdom theory, constructs a system dynamics model that integrates “digital technology-ecological perception-ecological wisdom capital” in a three-dimensional linkage. This model simulates the dynamic process through which sustainable food systems in urban–rural transition zones resist the risks of habitat fragmentation and achieve synergistic steady-state evolution. According to the simulation results, a synthesized steady-state transition in sustainable food systems can be regarded as a self-organizing phase transition process. During resource metabolism, system elements show strong nonlinear symbiotic and mutually beneficial features. Further, there is a significant time-lag effect on improving food system resilience through digital technology empowerment and policy coordination. Also, the effects of governance are not immediately visible. Further, as an important instrumental empowerment carrier, urban–rural spatial and information barriers can be broken through means like digital ecological monitoring. Moderate investment in this regard can promote the acceleration of the system’s self-organizing phase transition. Also, this can enhance resilience against disturbance from habitat fragmentation while ensuring food production and supply. Finally, the ecological carrying capacity of core food production spaces does not increase monotonically. This means that the system possesses an adaptive cyclical fluctuation mechanism, with a periodic oscillatory evolution of carrying capacity. This study breaks through static analytical paradigms, fills the quantitative research gap on the resilience evolution of peri-urban food systems driven by the integration of digital technology and ecological wisdom, and can provide scientific evidence and decision-making support for food–ecological collaborative governance in China’s urban–rural transition zones. Full article

After the global financial crisis, central banks used unconventional monetary policies, including quantitative easing (QE), to restore financial stability. Although several studies have analyzed the effects of these measures on financial markets, limited attention has been given to how central bank transparency influences the stability of commercial banks operating under these conditions. This study examines the impact of central bank transparency on national banking system vulnerability during periods of QE across eight economies from 2013 to 2019. Using a dynamic two-step generalized method of moments model based on bank-level data, the analysis includes bank-specific variables, monetary policy indicators, macroeconomic determinants, central bank characteristics, and structural factors of the banking sector and applies a fixed-effects panel regression model. The findings show that transparency moderates the effect of QE on bank vulnerability and strengthens banking system resilience. By emphasizing the role of central bank transparency as a key element of monetary policy, this research provides useful evidence for policymakers seeking to improve the effectiveness and credibility of unconventional monetary measures in different banking environments. Full article

With advances in robotic manipulation in recent years, tactile sensing has become increasingly important in scenarios where visual information is unreliable or insufficient. However, the development of learning-based tactile algorithms and policies is limited by the cost and time required to collect large-scale physical datasets. While robotic simulation offers an alternative for synthetic data generation, current simulation platforms, such as NVIDIA Isaac Sim, lack integrated capacitive tactile sensors. This paper presents a finite element method (FEM)-based digital twin of a capacitive tactile sensor and an extension for NVIDIA Isaac Sim that enables the real-time generation of synthetic tactile data directly within the simulation environment. The proposed system extracts nodal deformations from the Isaac Sim PhysX engine and uses a convolutional neural network (CNN) to predict synthetic tactile maps that replicate the response of the physical sensor. We further demonstrate adaptability by retraining the model from an initial sensor to a second capacitive sensor, the Robotiq TSF-85, operating under the same sensing principle. The complete generation pipeline executes in 8.04 ms per frame on the laptop configuration and 6.71 ms on the workstation, enabling real-time operation at 60 Hz on both, and at 120 Hz on the workstation. The similarity of the generated tactile data for the Robotiq TSF-85 is evaluated using complementary similarity metrics, achieving a mean Structural Similarity Index Measure (SSIM) of 0.727 ± 0.16 and a mean Pearson correlation of 0.87 ± 0.16 against real measurements. To demonstrate the utility of the proposed framework, a shape-recognition task (cylinder, sphere, cube) was performed using only synthetic tactile data and evaluated on real-world sensor data, achieving an accuracy of 69.3% with zero real training labels. By enabling integrated tactile simulation and synthetic data generation within Isaac Sim, this work provides a practical tool for tactile perception using capacitive tactile sensors. Full article

An increasing number of special Internet of Things (IoT) applications are being deployed within federated and zero-trust (ZT) environments. These ad-hoc networks consist of heterogeneous, resource-constrained devices from various administrative domains, all of which are susceptible to compromise. The dynamic nature of these environments necessitates near-real-time Situational Awareness (SA), where processed data varies with its sensitivity and reliability, without dependence on a central authority. Examples include NATO and non-NATO coalitions engaged in hybrid military operations or humanitarian aid scenarios. To address the challenges of security, reliability, and context-aware data dissemination, we propose $FedM$, a multi-level formal model designed for context-aware and policy-driven data dissemination in federated IoT environments. This model is built upon various access control models and Denning’s research on information flow control (IFC), prioritizing the protection and reliability of data flows. A crucial element of this model is the distributed ledger, which facilitates the dynamic modification of label expressiveness, enhances resilience against disruption attacks, and separates policy logic from application functionality to mitigate risks associated with the benevolent developer. Additionally, we delineate a deterministic and history- and precedence-aware policy enforcement procedure to resolve conflicting actions and introduce processing primitives for the ongoing Data Quality Assessment (DQA) process. Our model also aligns with the concepts of Ubiquitous and Continuum Computing. Furthermore, in our paper we illustrate a policy-based dissemination pipeline, incorporating a bounded trustworthiness dimension. Additionally, we present a refined multi-layered framework that proposes the deployment of Information Flow Control (IFC) components, such as the Open Policy Agent decision engine, to facilitate policy-driven contextual data dissemination. We provide preliminary benchmarks for resource-constrained platforms, along with a formal threat model that addresses implicit flows, the benevolent developer problem, and the behavior of a distributed ledger under degraded network conditions. Finally, we conduct a formal verification of our model using the P framework. Full article

The industrial chain forms a network of interconnected enterprises spanning from raw material procurement to final product distribution, enabling cost reduction, operational efficiency improvement, and enhanced market competitiveness. However, business resource conversion among enterprises often leads to information asymmetry, which impedes effective interconnection and collaboration. To address this challenge, WFC-Net (Workflow-Control Petri Net with Resource Fusion), a model tailored for multi-collaboration scenarios among interconnected enterprises in the industrial chain, is proposed. The proposed approach integrates WF-Net workflow characteristics with C-Net dependency modeling and Petri net transitions to enable precise workflow control and effective business resource coordination. The resource attributes are incorporated as first-class net elements, and a receding-horizon optimization policy is employed to dynamically adapt to varying operational conditions. Comparative simulation experiments demonstrate that WFC-Net achieves superior performance across all metrics, with an 89.1% authorization success rate and 36.0% event completion rate, outperforming Petri Net, C-Net, and WF-Net baselines. The full-rank reachability matrix provides a necessary condition for linearized controllability, offering a theoretical foundation for stable authorization behavior under the receding-horizon policy. These results demonstrate that WFC-Net consistently achieves or approximates target business-side metrics while ensuring controllability and soundness. Full article

The authorization and operation of the public data supply chain is an important pathway for unlocking the value of public data and cultivating the data element market. However, in practice, it faces challenges such as insufficient data supply and insufficient stakeholder incentives. This paper focuses on the differentiated subsidy policies of the fiscal department, constructing a differential game model involving multiple participants, including data providers, data managers, and data operators. The paper systematically compares the optimal effort decisions of each stakeholder, the evolution trajectory of public data product value, and the trajectory of overall system profits under two subsidy models: cost subsidies and transaction subsidies. It further analyzes the regulatory role of revenue distribution ratios and cost-sharing contracts in shaping the effectiveness of these subsidy mechanisms. The study finds that: (1) cost subsidies provide more balanced and stable incentives for all stakeholders and contribute more to the final value trajectory of public data products; transaction subsidies are more effective in improving overall system profits but offer weaker incentives for the supply and management sides, requiring flexible use in conjunction with cost-sharing contracts; (2) cost-sharing contracts play a regulatory role under different subsidy models and effectively reduce the data provider’s dependence on fiscal subsidies under the transaction subsidy mechanism; (3) the revenue distribution ratio only positively affects the effort decisions of the supply and management sides under the transaction subsidy model, and the optimal subsidy ratio of the fiscal department is closely related to the revenue distribution ratio. Therefore, differentiated subsidy strategies should be implemented based on specific decision-making contexts and internal revenue distribution ratios. This paper reveals the synergistic incentive mechanism between differentiated subsidy models and cost-sharing contracts, providing a theoretical basis for the design of subsidy policies for public data authorization and operation. Full article

New-quality productive forces provide an important conceptual lens for understanding how innovation-driven development, digital empowerment, and the green transition jointly support sustainable regional development. From a geographical perspective, this study develops a multidimensional evaluation system for new-quality productive forces based on the three elements of productive forces: laborers, means of labor, and objects of labor. Using panel data for 31 provincial-level administrative units in China from 2012 to 2022, we integrate the entropy weight method, standard deviation ellipse, exploratory spatiotemporal data analysis, the obstacle degree model, and the random forest model to examine the spatiotemporal evolution and influencing mechanisms of new-quality productive forces. The results show that: (1) China’s new-quality productive forces increased steadily during the study period, but their overall level remained relatively low and regional disparities continued to widen. Spatially, they exhibited a pronounced “high in the east and low in the west” pattern, with South China and East China maintaining leading positions and Guangdong and Jiangsu forming a dual-core growth structure. (2) The spatial center of gravity remained southeast of the Hu Huanyong Line, and its expansion direction was broadly parallel to this line, indicating a relatively stable spatial configuration. The ESTDA results further reveal significant positive spatial autocorrelation, strong temporal inertia, and marked path dependence in local spatial transitions. (3) High-tech talent supply, innovation and entrepreneurship vitality, and ecological governance capacity constitute the main internal bottlenecks constraining the development of new-quality productive forces. The analysis of external factors indicates that economic scale and population size are the primary predictors of NQPF development, whereas government intervention, openness, urbanization, and industrial structure exhibit varying degrees of nonlinearity and regional heterogeneity. These findings enrich the geographical interpretation of new-quality productive forces and provide empirical evidence for formulating differentiated regional innovation policies and productivity transformation strategies. Full article

Motorcyclists are among the most vulnerable road users at roundabouts, particularly in mixed-traffic environments where rider behaviour may be influenced by geometric design. This study investigates the association between roundabout geometry and risky motorcyclist behaviour using the Chi-squared Automatic Interaction Detection (CHAID) method. Video-based observations were conducted at four selected roundabouts in Kuching, Sarawak, Malaysia, generating 15,937 risky-behaviour events from 5400 observed motorcyclists. Six risky-behaviour categories were analysed, covering entry, circulation, and exit manoeuvres. The CHAID results showed that entry radius was the primary geometric factor associated with risky motorcyclist behaviour, while exit radius and exit width acted as secondary variables under specific entry-radius conditions. Four behavioural scenarios were identified. Entry radii of 15–32 m were associated with mixed risky-behaviour patterns, with lane splitting during circulation being the most frequent behaviour. Entry radii of 37–40 m combined with exit radii ≤ 12.43 m were associated with failure to signal before exiting. Entry radii of 43–49 m combined with exit radii ≤ 25.3 m were associated with improper lane positioning when exiting. Larger entry radii of 49–64 m combined with exit widths of 7.38–9.06 m were associated with close stopping or potential blind-zone positioning. The model validation results indicated moderate internal classification performance, supporting the use of CHAID as an interpretable threshold-identification tool rather than a high-precision predictive model. The findings demonstrate that risky motorcyclist behaviour at roundabouts is shaped by non-linear interactions between entry and exit geometric elements. From a sustainability perspective, these results provide preliminary evidence for behaviour-sensitive roundabout design, safety assessment, and policy-oriented geometric improvements that support safer and more inclusive urban transport systems in motorcycle-dominant mixed-traffic contexts. Full article