Search Results (89)

Objective: The classic excitation/inhibition dichotomy may be insufficient to describe rTMS mechanisms in the aging brain. This study investigated immediate whole-brain resting-state functional connectivity effects of 10 Hz (high-frequency) and 1 Hz (low-frequency) rTMS over the left dorsolateral prefrontal cortex (DLPFC) in healthy older adults. Methods: Thirty healthy older adults (aged 60–75 years) participated in a randomized, single-blind, crossover study, and underwent 20-min 10 Hz and 1 Hz rTMS in separate visits. A 106-channel fNIRS system was used to record resting-state activity before and immediately after each intervention. Functional connectivity was analyzed at the channel, region-of-interest (ROI) and network summary levels, including graph-theoretic metrics and distance-stratified connectivity summaries. Results: At the network summary level, 10 Hz stimulation was associated with relatively more positive changes in global topology and spatially distributed connectivity summaries, whereas 1 Hz stimulation showed the opposite overall trend. In the graph-theoretic analyses, stimulation frequency × time interaction effects were observed for global efficiency, local efficiency, clustering coefficient, and mean node strength. At the edge level, only a small number of effects survived FDR correction, and the broader connection-wise patterns were therefore interpreted as exploratory. Uncorrected analyses suggested widespread enhancement after 10 Hz stimulation and widespread reduction after 1 Hz stimulation, together with localized paradoxical effects, including selective decreases after 10 Hz and selective increases after 1 Hz (e.g., bilateral primary motor cortex connectivity). Conclusions: These findings suggest that 10 Hz and 1 Hz rTMS over the left DLPFC are associated with different patterns of immediate whole-brain network reconfiguration in healthy older adults. The presence of localized paradoxical effects further suggests that rTMS responses in the aging brain may involve more complex forms of reorganization than a simple excitatory/inhibitory dichotomy would predict. Significance: The present study provides preliminary support for a network-level perspective on neuromodulation in older adults and highlights the value of whole-brain fNIRS for characterizing distributed responses to rTMS. Larger, sham-controlled, behavior-linked, and longitudinal studies are needed to determine the robustness and functional significance of these effects. Full article

Pinching-antenna systems (PASSs) offer a low-complexity and reconfigurable solution for near-field downlink communications by deploying multiple radiating elements along a single waveguide. Existing studies mainly assume simplified propagation conditions or focus on spectral efficiency, while the impact of environment-dependent interference patterns arising from user-specific blockage conditions on energy-efficient design remains unclear. An energy-efficient downlink design for single-waveguide PASS based on environment-division multiple access (EDMA) is investigated. Under a given propagation environment, EDMA exploits user-dependent blockage and visibility differences through proper pinching-antenna placement, thereby inducing different multi-user interference patterns without increasing radio-frequency hardware complexity. We examine how such blockage-dependent interference influences the relationship between spectral efficiency and energy efficiency, and develop an energy-aware EDMA framework that jointly considers pinching-antenna locations and transmit power allocation under quality-of-service constraints. The resulting coupled design problem is solved through an alternating optimization procedure. EDMA is compared with conventional time-division multiple access (TDMA) using a unified hardware and power-consumption model. Numerical results reveal clear energy-efficiency threshold behaviors with respect to blockage intensity, user population, and service requirements. The results further show that EDMA can significantly outperform TDMA in specific operating regimes. Full article

This study empirically investigates how Environmental, Social, and Governance (ESG) discourses among major Korean Business-to-Business (B2B) corporations (POSCO, LG Chem, and HD Hyundai) were reconfigured in the context of former President Trump’s re-election campaign and the 2024 U.S. presidential election. The observation periods were divided into the Pre-Trump period (1 May 2023 to 30 April 2024) and the Post-Trump period (1 May 2024 to 30 April 2025). External discourses were examined using social media, news, and blog posts, while internal discourses were analyzed through the CEO’s New Year addresses from 2021 to 2025. Keyword frequency analysis and co-occurrence network analysis, conducted via the ‘Sometrend’ platform, were combined to trace structural transitions in corporate discourses. The results show that: (1) the relative share and network centrality of environmental (E) keywords declined in the Post-Trump period, with several environmental terms losing core positions and becoming peripheral or bridging nodes, while policy- and economic-related terms increased; (2) social (S) and governance (G) keywords appeared only sporadically and remained peripheral across periods; (3) temporal concentrations of policy–economic keywords coincided with significant political and market-related events, such as financial volatility in 2023 and the tariff policy announcement in February 2025, indicating temporal alignment rather than deterministic causality; (4) firm-level differences were evident: POSCO exhibited the most pronounced structural shift, LG Chem’s discourses increasingly emphasized supply chain and investment-related terms alongside environmental keywords, and HD Hyundai showed a shift toward more risk- and operation-oriented keywords in the later period; and (5) CEO New Year addresses displayed directionally consistent patterns with external discourse, supporting cross-textual alignment. These findings demonstrate that ESG discourse is not a fixed normative language but a strategically adaptive frame that varies according to political–economic contexts and industrial conditions. The relative weakening of the environmental frame in terms of discourse centrality, alongside the strengthening of the policy–economic frame, differed by industry, reflecting variations in regulatory exposure and operational characteristics. By observing ESG discourses longitudinally and comparatively, this study provides empirical evidence of how political and industrial dynamics reshape corporate discourses and CEO communication. Moreover, keyword frequency and co-occurrence network analysis are validated as effective methods for identifying discourse shifts, offering both academic contributions and practical implications for corporate communication analysis. Full article

This paper proposes a frequency-reconfigurable and active beam-switching antenna based on an X-shaped slot array integrated with a diode-based switching network. The proposed antenna features four slots arranged at 90° intervals around the feed point. Each slot is integrated with two PIN diodes and one varactor diode. By selectively activating a specific slot through the PIN diodes, the radiation pattern can be switched in four directions at 90° intervals. Dual-band operation is achieved using varactor diodes, and by controlling their equivalent capacitance, the antenna covers two operating bands: a low-frequency band with a 29.51% bandwidth (2.6–3.5 GHz) and a high-frequency band with a 24.52% bandwidth (3.65–4.67 GHz). These frequency ranges include the 5G sub-6 GHz bands, specifically n77 and n78. Experimental results confirm stable beam-switching performance across the entire operating frequency range. Full article

A hybrid AI and LLM-enabled architecture is presented for real-time decision support in industrial batch processes, where supervision still relies heavily on human operators and ad hoc SCADA logic. Unlike algorithmic contributions proposing novel AI methods, this work addresses the practical integration and deployment challenges arising when applying existing AI techniques to safety-critical industrial environments with legacy PLC/SCADA infrastructure and real-time constraints. The framework combines deterministic rule-based agents, fuzzy and statistical enrichment, and large language models (LLMs) to support monitoring, diagnostic interpretation, preventive maintenance planning, and operator interaction with minimal manual intervention. High-frequency sensor streams are collected into rolling buffers per active process instance; deterministic agents compute enriched variables, discrete supervisory states, and rule-based alarms, while an LLM-driven analytics agent answers free-form operator queries over the same enriched datasets through a conversational interface. The architecture is instantiated and deployed in the Clean-in-Place (CIP) system of an industrial beverage plant and evaluated following a case study design aimed at demonstrating architectural feasibility and diagnostic behavior under realistic operating regimes rather than statistical generalization. Three representative multi-stage CIP executions—purposively selected from 24 runs monitored during a six-month deployment—span nominal baseline, preventive-warning, and diagnostic-alert conditions. The study quantifies stage-specification compliance, state-to-specification consistency, and temporal stability of supervisory states, and performs spot-check audits of numerical consistency between language-based summaries and enriched logs. Results in the evaluated CIP deployment show high time within specification in sanitizing stages (100% compliance across the evaluated runs), coherent and mostly stable supervisory states in variable alkaline conditions (state-specification consistency ${\Gamma }_s\ge 0.98$), and data-grounded conversational diagnostics in real time (median numerical error below 3% in audited samples), without altering the existing CIP control logic. These findings suggest that the architecture can be transferred to other industrial cleaning and batch operations by reconfiguring process-specific rules and ontologies, though empirical validation in other process types remains future work. The contribution lies in demonstrating how to bridge the gap between AI theory and industrial practice through careful system architecture, data transformation pipelines, and integration patterns that enable reliable AI-enhanced decision support in production environments, offering a practical path toward AI-assisted process supervision with explainable conversational interfaces that support preventive maintenance decision-making and equipment health monitoring. Full article

Reconfigurable intelligent surface (RIS)-aided index modulation (IM) shows great potential for next-generation wireless communications. Nevertheless, obtaining channel state information (CSI) for RIS-based IM incurs high pilot overhead, particularly for multi-domain IM. In this paper, we integrate orthogonal frequency division multiplexing into RIS-aided differential reflecting modulation (DRM) communications, introducing the differential reflecting frequency modulation (DRFM) system. In DRFM, information bits are jointly conveyed through the activation permutations of reflecting patterns, grouped carriers, and constellation symbols. The transmitter combines the differentially coded reflecting-time block and the time–frequency block using the Kronecker product. This allows DRFM to operate without relying on CSI at the transmitter, RIS, or receiver. Moreover, we design a novel high-rate quadrature amplitude modulation (QAM) scheme for DRFM. Compared to PSK-based DRFM, this QAM scheme can boost either the throughput or the performance of DRFM. Simulation results illustrate the superiority of the DRFM system, along with an acceptable SNR penalty, compared to non-differential modulation with coherent detection. At the same spectral efficiency, the proposed QAM-aided DRFM outperforms schemes using traditional PSK, amplitude phase shift keying (APSK), and star-QAM constellation modulations. Full article

A reconfigurable analog beamformer for the use case of multiband Global Navigation Satellite System (GNSS) multiantenna receiver systems is designed and tested. The beamformer board operates in all existing GNSS frequency bands. In this paper, the two commonly used GNSS bands, the E1/L1 and E5a/L5 GNSS bands at 1.575 GHz and 1.176 GHz, respectively, are studied. An analog weighting of the complex excitation of up to 14 individual channels is realized using attenuators and phase shifters, digitally controlled by proprietary PC software. We present an analysis of the relative errors between the channels and a simple calibration of constant errors which is applied and validated. The beamformer is then demonstrated in an exemplary test case, to generate an ad hoc pattern from an array of antennas. Full article

Unmanned Aerial Vehicles (UAVs) are integral components of future 6G networks, offering rapid deployment, enhanced line-of-sight communication, and flexible coverage extension. However, UAV communications in low-altitude environments face significant challenges, including rapid link variations due to attitude instability, severe signal blockage by urban obstacles, and critical sensitivity to transmitter–receiver alignment. While traditional planar reconfigurable intelligent surfaces (RIS) show promise for mitigating these issues, they exhibit inherent limitations such as angular sensitivity and beam squint in wideband scenarios, compromising reliability in dynamic UAV scenarios. To address these shortcomings, this paper proposes and evaluates a spherical-cap reflective intelligent surface (ScRIS) specifically designed for dynamic low-altitude communications. The intrinsic curvature of the ScRIS enables omnidirectional reflection capabilities, significantly reducing sensitivity to UAV attitude variations. A rigorous analytical model founded on Generalized Sheet Transition Conditions (GSTCs) is developed to characterize the electromagnetic scattering of the curved metasurface. Three distinct 1-bit RIS unit cell coding arrangements, namely alternate, chessboard, and random, are investigated via numerical simulations utilizing CST Microwave Studio and experimental validation within a mechanically stirred reverberation chamber. Our results demonstrate that all tested ScRIS coding patterns markedly enhance electromagnetic field uniformity within the chamber and reduce the lowest usable frequency (LUF) by approximately 20% compared to a conventional metallic spherical reflector. Notably, the random coding pattern maximizes phase entropy, achieves the most uniform scattering characteristics and substantially reduces spatial field autocorrelation. Furthermore, the combined curvature and coding functionality of the ScRIS facilitates simultaneous directional focusing and diffuse scattering, thereby improving multipath diversity and spatial coverage uniformity. This effectively mitigates communication blind spots commonly encountered in UAV applications, providing a resilient link environment despite UAV orientation changes. To validate these findings in a practical context, we conduct link-level simulations based on a reproducible system model at 3.5 GHz, utilizing electromagnetic scale invariance to bridge the fundamental scattering properties observed in the RC to the application band. The results confirm that the ScRIS architecture can enhance link throughput by nearly five-fold at a 10 km range compared to a baseline scenario without RIS. We also propose a practical deployment strategy for urban blind-spot compensation, discuss hybrid planar-curved architectures, and conduct an in-depth analysis of a DRL-based adaptive control framework with explicit convergence and complexity analysis. Our findings validate the significant potential of ScRIS as a passive, energy-efficient solution for enhancing communication stability and coverage in multi-band 6G networks. Full article

Global data consumption is experiencing exponential growth, driving the demand for wireless links with higher transmission speeds, lower latency, and support for emerging applications such as 6G. A promising approach to address these requirements is the use of higher-frequency bands, which in turn necessitates the development of advanced antenna systems. This work presents the design and experimental validation of a reconfigurable, low-cost leaky-wave antenna capable of controlling the propagation direction of single-, dual-, and triple-beam configurations in the FR3 frequency band. The antenna employs slotted periodic patterns to enable directional electromagnetic field leakage, and it is based on a cost-effective and simple 3D-printing fabrication process. Laboratory testing confirms the theoretical and simulated predictions, demonstrating the feasibility of the proposed antenna solution. Full article

This study examines how the Donggyeong Daejeon (東經大全), the principal scripture of early Donghak, receives and theologically reconfigures the conceptual lexicon of Confucian classics through text mining-based analysis. Drawing on the classical Chinese texts of the Four Books and the Donggyeong Daejeon, and employing computational techniques such as keyword frequency, keyword-in-context (KWIC), and co-occurrence mapping, the study identifies structural parallels and semantic shifts across the two corpora. These patterns are then interpreted hermeneutically to assess how early Donghak appropriates, repurposes, and theologically transforms inherited Confucian categories. Findings suggest that while the Donggyeong Daejeon retains key Confucian terms, it situates them within a distinct theological framework. The Confucian triad of human being, the Way, and Heaven (人–道–天), for example, is recast in Donghak as “Heaven’s heart is the human-heart” (天心卽人心), a theological affirmation of the human as the locus of Heaven’s immanence. Similarly, the Confucian virtue of sincerity (誠) is reinterpreted through the lens of faith (信), transforming it from a metaphysical ideal into a performative mode of spiritual judgment. Most notably, the Confucian dualism of li (理) and qi (氣) is overcome through the theology of “ultimate energy” (至氣), a divine substance that animates and unifies all beings. By combining quantitative text analysis with interpretive discussion, this study presents Donghak not as a rhetorical appropriation of Confucian discourse, but as a conceptual innovation rooted in the resemanticization of its inherited language. This methodology offers a new model for tracking doctrinal transformation in East Asian religious texts and contributes to broader discussions on intertextual borrowing, and the semantic evolution of classical traditions. Full article

This paper presents a wideband multi-linear polarization reconfigurable antenna featuring five linear polarization states. We use the semi-ellipsoidal dipoles as the main radiators to broaden the operating bandwidth; the states of linear polarizations are switched by controlling the ON/OFF of PIN diodes between feeding pads and dipoles to excite a specific pair of dipoles. A 7 × 7 AMC array is added below the antenna to obtain a small height of 0.14 λ₀ (λ₀ is the free space wavelength at the operating frequency). Prototypes of the designed antenna are fabricated, and experimental results illustrate that the proposed antenna yields an impedance bandwidth of 50% (from 2.25 GHz to 3.75 GHz) for all polarization states, stable radiation patterns, and low cross-polarization within the operating band. In addition, the maximum gain reaches 8.1 dBi. The proposed five linear-polarized switching antenna with wide band and low-profile features can be applied in reconfigurable conformal array antennas, thus flexibly realizing linear polarization reconfiguration of conformal arrays in radar and military platforms. Full article

Forest fire regimes are undergoing systematic reorganization under climate change, particularly in monsoon–human coupled ecosystems such as Southeastern China, where risk dynamics remain poorly quantified. This study proposes a meteorology-driven machine learning model designed to assess long-term forest fire risk. Using kernel density estimation and standard deviational ellipse analysis, we assessed the spatiotemporal patterns of fire risk during the observational period and their future shifts across the SSP1-2.6 and SSP5-8.5 scenarios. The results indicate a significant overall decline in fire frequency from 2008 to 2024 (−467.3 fires/year, representing an annual average reduction of 10.8%, p < 0.001), which is attributed primarily to enhanced regional fire prevention and control measures, yet with a notable reversal after 2016 in Guangdong and Fujian. Fires are highly seasonal, with 74% occurring in the dry season (December–March). The meteorologically driven random forest model exhibited excellent performance (R² = 0.889), validating meteorological conditions as key drivers of regional fire dynamics. It is projected that intensified warming (+5.5 °C under SSP5-8.5) and increased precipitation variability (+23%) are likely to drive pronounced northward and inland migration in high-risk zones. Our projections indicate that by the end of the century, high-risk area coverage could expand to 19.2%, with a shift from diffuse to clustered patterns, particularly in Jiangsu and Zhejiang. These findings underscore the critical role of hydrothermal reconfiguration in reshaping fire risk geography and highlight the need for dynamic, region-specific fire management strategies in response to compound climate risks. Full article

A reconfigurable microwave absorber based on double-layer metasurface is proposed for wide microwave band applications spanning 3 to 14 GHz. The absorber consists of two layers with two-dimensional array of four-semi-circular and square-ring metasurface patches loaded impedance devices, two spacers composed of honeycomb materials, and a bottom copper substrate. In order to break through the limitation of single-layer absorbers at finite resonant frequencies, a special double-layered metasurface structure is adopted. The layer I of metasurface is designed with two resonant peaks near the X band and transmission performance in the C band. Simultaneously, the layer II of metasurface is designed with a resonant peak near the C band and reflection performance in the X band. To achieve a reconfigurable effect, impedance adjustable device, such as PIN diodes, are connected between patterned metasurface cells of layer I. The simulation results revealed that the double-layer metasurface absorber can not only achieve broadband absorption effect, with the reflection value below −10 dB from 3.1 to 14.2 GHz, but also adjust the electromagnetic absorption rate, with the reflection value below −20 dB covers a bandwidth of 6.6–9 GHz. The good agreement between simulation and measurement validates the proposed absorber. Full article

A surface-wave-assisted, dual-band, circularly polarized reconfigurable intelligent surface is proposed that allows arbitrary beam-shaping capability within the [4.35 GHz–4.5 GHz] and [11.8 GHz–12.3 GHz] frequency bands. In particular, alongside the proposed physical design of the surface, a genetic algorithm-based design framework is introduced to enable the synthesis of complex radiation patterns beyond simple beam steering. It is shown that the phase profiles obtained from the proposed optimization scheme naturally lead to the excitation of surface waves, which facilitate arbitrary beam shaping by satisfying the local power conservation condition between the normally impinging and arbitrarily reflected waves. To physically construct the proposed surface, cascaded symmetric unit cells are employed to facilitate circular polarization operation and realize dual-band operation. Furthermore, varactor diodes are incorporated into the design of unit cells so that the reflection phase can be independently and continuously tuned across the two frequency bands, with a tuning range of 300 degrees. The versatility of the proposed surface is demonstrated through design examples that achieve (i) unidirectional beam steering, (ii) multi-directional beam steering, and (iii) sector-beam formation within each frequency band. Full article

This paper describes a compact multi-port sub-6 GHz multiple-input multiple-output (MIMO) antenna system tailored for 5G NR mobile terminals operating in the n77 (3.3–4.2 GHz), n78 (3.3–3.8 GHz), and n79 (4.4–5.0 GHz) frequency bands. The proposed design leverages a shared coupling approach that exploits the smartphone metal frame as the radiating element, facilitating efficient integration within the spatial constraints of modern mobile devices. A two-stage method is used to mitigate the mutual coupling and correlation issues typically encountered when designing compact MIMO configurations. Initially, a four-port structure is used to evaluate broadband impedance and spatial feasibility. Based on the observed limitations in terms of isolation and the envelope correlation coefficient (ECC), the final configuration was reconfigured as an optimized two-port layout with a refined coupling geometry and effective current path control. The fabricated two-port prototype exhibited a measured voltage standing wave ratio below 3:1 across the n78 band on both ports, with the isolation levels attaining –12.4 dB and ECCs below 0.12. The radiation efficiency exceeded −6 dB across the operational band, and the radiation patterns were stable at 3.3, 3.5, and 3.8 GHz, confirming that the system was appropriate for MIMO deployment. The antenna supports asymmetric per-port efficiency targets ranging from −4.5 to −10 dB. These are the realistic layout constraints of commercial smartphones. In summary, this study shows that a metal frame integrated two-port MIMO antenna enables wideband sub-6 GHz operation by meeting the key impedance and system-level performance requirements. Our method can be used to develop a scalable platform assisting future multi-band antenna integration in mass-market 5G smartphones. Full article