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Optimal planning of integrated energy systems considering multi-day low-output events and efficiency degradation of electrolyzer
No full textHydrogen storage plays a key role in mitigating the long-term fluctuations in integrated energy systems (IESs), such as the multi-day low-output events (MLEs) that last for several days. However, most studies do not consider the impacts of the MLEs on the IES planning. Therefore, this paper proposes an optimal planning for IESs considering the MLEs of wind power and the efficiency degradation of electrolyzer (EZ). First, a comprehensive evaluation index characterizing the severity of the MLE is proposed. On this basis, a novel representative chronological time period clustering (RCTPC) method is proposed to preserve the MLEs during the clustering, where the MLEs and regular intraday fluctuations are clustered separately. Moreover, an improved IES planning model considering the MLEs of wind power and hydrogen storage is further proposed to address the long-term fluctuations, where an EZ model considering the efficiency degradation is developed with different load rates and continuous operation time. Finally, the methodology is validated on an IES comprising an IEEE 33-node power network and 6-node heat network. Numerical results show that the proposed RCTPC can better retain MLE in the clustering process, and considering the efficiency attenuation of EZ can reduce the total annual cost by 4.13%. This method provides guidance for IES planning under extremely renewable intermittent conditions.<br/
Polar-domain multi-user key generation in near-field communications
No full textGiven the substantial increase in the number of antennas in extremely large-scale antenna array (ELAA) systems, polar-domain channel modeling has been introduced to capture both angular and distance information in near-field environments. The fine-grained polar-domain channel provides additional sources of randomness, making it well-suited for physical layer key generation (PLKG). To minimize the pilot overhead in multi-user key generation and leverage the randomness from the polar-domain channel paths, we implement a zero-forcing (ZF)-based precoding scheme to mitigate the inter-path and inter-user interference. Using ZF precoding, we derive an analytical expression for the sum secret key rate (SKR) as a function of the power allocation variables, and then optimize these variables in the presence of eavesdroppers. Since the ZF method may not fully eliminate interference with imperfect channel state information (CSI), there could be correlation between the measurements of polar-domain channel paths and users. We present a channel decorrelation and reciprocity compensation approach that leverages principal component analysis (PCA) and deep neural networks (DNNs) to mitigate channel correlation issues. Specifically, PCA is first applied at the base station (BS) to decorrelate the composite CSI vector that aggregates the CSI of all users. Following this preprocessing, a DNN is trained to learn the mapping from the decorrelated uplink CSI to the corresponding original downlink CSI. This trained DNN then reconstructs a new version of the downlink CSI, enhancing the cross-correlation between the BS and the users’ CSI, thereby improving uplink/downlink reciprocity. Our simulations evaluate the effectiveness of the DNN-based reciprocity compensation by assessing the normalized mean squared error (NMSE) and the correlation between uplink and downlink CSI, the bit disagreement ratio (BDR) and the randomness of secret keys after quantization.<br/
UAV-assisted federated learning with robust resource and trajectory optimization under location uncertainties
No full textFederated learning (FL) has emerged as a promising solution to facilitate the deployment of artificial intelligence (AI) on wireless devices. However, heterogeneity of wireless devices, including disparities in computation capabilities, data sizes, and energy constraints, introduces delays in the FL completion time, particularly due to inefficient communication and slow updates from resource-constrained devices. To address this issue, we propose an unmanned aerial vehicle (UAV)-assisted FL framework that integrates UAV as a central server, collaborating with the devices to facilitate the model training process. Accordingly, we jointly consider computation and transmission strategies, as well as the task assignment and UAV trajectory to minimize the completion time of the FL process. Particularly, we consider the location uncertainties associated with the devices, along with the consequent chance-constrained aggregation process, to achieve a robust learning process. We employ the Bernstein-type inequalities to reformulate the probabilistic-form optimization into its deterministic counterpart. Then we solve the problem under a block coordinate descent framework. Simulation results demonstrate that the proposed approach significantly reduces the completion time of FL and achieves robust performance guarantee in the presence of location deviations.<br/
Practicing the economic-cultural-capital association through education as rational capital in school choice
No full textWhile cultural mobility theories highlight the influence of environmental conditions on the returns of cultural capital—an aspect often overlooked by Bourdieusians—both the cultural capital and cultural mobility perspectives tend to assume a linear relationship between economic capital and cultural capital. They rarely account for possible nonlinear dynamics that may be shaped by educational training. This study aims to investigate the role of education in the economic–cultural-capital formula through the lens of school choice. Using a sample of 11,938 students randomly sampled from 350 schools in the PISA 2018 dataset, we applied Propensity Score Matching (PSM) and Hierarchical Linear Modeling (HLM) to analyze school choice stra-tegies. Our findings reveal that different constitutions of economic cultural and cultural capital engender distinct school choice strategies. Respondents with high cultural capital and regular reading habits are inclined to make rational decisions to select less competitive schools, with the intention of optimizing their children’s academic outcomes. In contrast, wealthy individuals lacking cultural capital tend to engage in the high-stakes gamble of choosing more competitive schools, often through purchasing homes in prestigious school districts — a strategy that significantly amplifies their children’s risk of academic failure. This irrational approach appears to stem from these parents’ limited educational attainment, which hinders their ability to recognize the actual value of cultural capital. These findings highlight the critical role of education as rational capital in mediating the conversion of economic capital to cultural capital and, consequently, governing school choice behaviours and educational outcomes
Hybrid centralized-distributed precoding in fronthaul-constrained CF-mMIMO systems
No full textWe investigate a fronthaul-limited cell-free massive multiple-input multiple-output (CF-mMIMO) system and propose a hybrid centralized-distributed precoding strategy that dynamically adapts to varying fronthaul and spectral efficiency (SE) requirements. The proposed approach divides users into two groups: one served by centralized precoding and the other by distributed precoding. We formulate a novel optimization problem for user grouping and power control aimed at maximizing the sum SE, subject to fronthaul and per-access point (AP) power constraints. To tackle the problem, we transform it into a tractable form and propose efficient solution algorithms. Numerical results confirm the hybrid scheme’s versatility and superior performance, consistently outperforming fully centralized and distributed approaches across diverse system configurations.<br/
Insider ownership and investment efficiency
No full textThis study examines the relationship between insider ownership and investment efficiency in Indian publicly listed firms, utilising panel data spanning 2001 to 2015. It explores how agency conflicts contribute to suboptimal capital investment decisions. Our analysis reveals that increased insider ownership is associated with reduced investment efficiency, primarily due to tendencies towards overinvestment rather than underinvestment. This pattern suggests that insiders may favour personal or empire-building interests over shareholder value maximisation. Notably, the presence of independent directors on the board serves as a significant counterbalance, mitigating these inefficiencies. These findings hold when tested with different metrics for capital investment and investment opportunities. This research contributes to the literature by detailing the complex influence of ownership structure on investment behaviour and underscores the critical role of governance mechanisms, particularly board independence, in aligning investments with value creation. The insights are especially pertinent for developing economies with similar investor protection frameworks.<br/
Integrated sensing and communications for pinching-antenna systems (PASS)
No full textAn integrated sensing and communication (ISAC) design for pinching antenna systems (PASS) is proposed, where the pinching antennas are deployed to establish reliable line-of-sight communication and sensing links. More particularly, a separated ISAC design is proposed for the two-waveguide PASS, where one waveguide is used to emit the information-bearing signals for ISAC transmission while the other waveguide is used to receive the reflected echo signals. Based on this framework, a penalty-based alternating optimization algorithm is proposed to maximize the illumination power as well as ensure the communication quality-of-service requirement. Numerical results demonstrate that the proposed PASS-ISAC scheme outperforms the conventional antenna scheme
Platform dynamics and hydrodynamic assessment of TriFloatSol offshore floating solar
No full textThis study presents a numerical analysis of the hydrodynamic behaviour of floating solar platform (FSP) arrays under irregular wave conditions. A three-column FSP, originally designed for the North Sea, is expanded to include multi-body configurations, 3-TriFloatSol and 4-TriFloatSol, connected by double-ended ball-jointed rigid beams. The analyses focus on interactions within the platform arrays, changes in the air gap, and the effect of array configuration on dynamic performance. Results indicate minimal operational concern regarding the air gap, although occasional negative air gaps are observed in some bodies under worst-case scenarios. The interconnected configurations effectively reduce relative motions, keeping safe distances between platforms and limiting longitudinal and lateral displacements to around 2 m, compared to the 5.7 m column diameter. Spectral analysis reveals two resonance peaks in surge and sway: a low-frequency response (< 0.2 rad/s), attributed to the influence of springs (mooring lines), and a high-frequency peak (~ 1.8 rad/s), resulting from structural coupling. Elevated eigenfrequencies for heave, pitch, and roll (> 1.3 rad/s) are also observed, indicating potential for amplified motions in low-energy sea states. These results highlight key hydrodynamic features of FSP arrays and, at the conceptual design level, can guide future investigations and support the development of more refined models and design strategies
Correction: Development of rapidly dissolving microneedles integrated with valsartan-loaded nanoliposomes for transdermal drug delivery: in vitro and ex vivo evaluation (Pharmaceutics, (2025), 17, 4, (483), 10.3390/pharmaceutics17040483)
No full textIn the original publication [1], there was a mistake in the legend for Figure S3. The original Figure S3 displayed a 3D response surface and contour plot related to zeta potential, but it was intended to show the impact of variables on the entrapment efficiency of VAL-LP (Supplementary Material). The correct legend appears below. Figure S3. Independent variable’s comparative impact on entrapment efficiency of VAL-LP by 3D response surface and contour plot. In the original publication [1], there was a mistake in Figure S9. The subfigure labeled “FD-LIPO-DMNs” was mistakenly included in Figure S9. This subfigure does not represent data relevant to the current study and was included by mistake (Supplementary Material). The correct Figure S9 appears below. Digital images of parafilm layers showing the insertion of optimized VAL-LP-DMNs (magnification 2×). There was a mistake in Figure S3 as published. The original Figure S3 displayed a 3D response surface and contour plot related to zeta potential, but it was intended to show the impact of variables on the entrapment efficiency of VAL-LP (Supplementary Material). The corrected Figure S3 appears below. Independent variable’s comparative impact on entrapment efficiency of VAL-LP by 3D response surface and contour plot. The authors state that the scientific conclusions are unaffected. This correction was approved by the Academic Editor. The original publication has also been updated.</p
Tararira, une histoire de résistance et de resilience
No full textLe 31 septembre 1936, Fondane écrivait à sa femme et à sa sœur pour leur expliquer l'expérience complexe et difficile de la création de Tararira:Certes, Tararira est un film réalisé dans les pires conditions. Certes, il y a des lacunes et des défauts – même pas dus à mon inexpérience. Mais il y a aussi de bons moments et une audace qu'on attendrait de son mari et de son frère. (Écrits pour le cinéma, 2007, p. 197)<br/