Search Results (1,224)

Due to increasing human activities underwater, there is a growing demand for high-speed underwater optical communication (UOWC) data links for security surveillance, environmental monitoring, pipeline inspection, and other applications. Line-of-sight communication is impossible under certain conditions due to misalignment, physical obstructions, irregular usage, and difficulty adjusting the receiver orientation, especially when used in environments with mobile users or submerged sensor networks. Therefore, non-line-of-sight (NLOS) optical communication is used in this study. Advanced modulation schemes—quadrature amplitude modulation and orthogonal frequency-division multiplexing (QAM-OFDM)—were used to transmit the signal underwater between two network nodes. QAM increases the data transfer rate, while OFDM reduces dispersion and inter-symbol interference (ISI). The proposed UOWC system is investigated using a 532 nm green laser diode (LD). Reliable high-speed data transmission of up to 15 Gbps is achieved over horizontal distances of 134 m, 43 m, 21 m, and 5 m in four different aquatic environments—pure water (PW), clear ocean (CLO), coastal ocean (COO), and harbor II (HarII), respectively. The system achieves effectively error-free performance within the simulation duration (BER < 10⁻⁹), with a received optical signal power of approximately −41.5 dBm. Clear constellation patterns and low BER values are observed, confirming the robustness of the proposed architecture. Despite the limitations imposed by non-line-of-sight (NLOS) communication and the diversity aquatic environments, our proposed architecture excels at underwater long-distance data transmission at high speeds. Full article

The territorial development of the city of Brno during the 19th–21st centuries meant not only the growth of built-up areas (residential, industrial, commercial), but also the absorbing of segments of the ancient rural agricultural landscape. Within the current borders of the city of Brno, a number of green areas have been preserved, which have spontaneously developed from the original agricultural landscape, without being the result of urban planning. In half of the cases (17 out of a total of 34), they have still preserved the traditional small-scale division of land. Among the 10 medium-sized Moravian cities (between 30,000 and 400,000 inhabitants) in the historical region of Moravia in the east of the Czech Republic, the presence of 34 remnants of the ancient rural landscape in the city of Brno is quite exceptional (in Ostrava only 1; in other cities 0). The subject of the research is the inventory of such segments within the city borders and an attempt to explain their location in the city, state, focusing on the role of natural factors, land ownership and personal and recreational interests of residents. Segments of the ancient rural cultural landscape were identified by comparing the current landscape on aerial photographs with the landscape image on cadastral maps from the 1820s–1830s. Additional data on their natural and cultural properties were obtained through archival and field research. The segments were classified according to their degree of preservation and forms of threat. The results show that the remains of the ancient rural cultural landscape in the city of Brno have generally been preserved in locations that, due to the slope of the slopes, unsuitable building subsoil and poor soil, but locally on warm southern slopes, were not suitable for construction for the time being. Urban gardening contributes to their preservation and these areas are part of the city’s greenery. However, urban gardening also contributes to the destruction of these remnants. In 17 cases, the land was completely re-divided, built up with recreational facilities and overgrown with trees due to poor care. Another 17 locations are threatened by this process due to ignorance of their historical value, although this is essentially a positive development in terms of benefits for the city’s residents—land users. Although the Master Plan of the city of Brno foresees the existence of garden colonies in the future, it does not address the importance of the best-preserved segments as historical heritage. Community agriculture can play a positive role in maintaining segments of rural heritage within the city. Full article

In this article, the authors address the Serbian media narrative about the EU’s communication on lithium mining in Serbia. In an effort to answer the question of how this narrative can influence the positioning of the EU on Serbia as a candidate country for EU membership, the authors have made a research based on a quantitative–qualitative analysis of media coverage, drawing on a sample of 192 articles (N = 192) published by four Serbian online news portals (RTS, N1, B92, and Blic). The analysis leads to two main conclusions: (1) It indicates an inversion in the general approach to foreign policy orientation across the analyzed media platforms. The customary discourses on Serbia’s foreign policy trajectory temporarily diverged from established patterns—specifically, the fervently pro-Western orientation characteristic of anti-government platforms and the ostensibly West-sceptical orientation typical of pro-government media. This reinforces the argument that the primary structuring line of media discourse in Serbia lies in the division between pro-regime and anti-regime orientations. (2) Media repositioning has exerted a pronounced negative effect on pro-European segments of the Serbian public, reactivating the thesis of “stabilocracy”, conceptualized as the dynamic relationship between authoritarian regimes in the Balkans and their external supporters. According to the authors, the EU’s inability to anticipate the drastic negative shift in public sentiment toward it—particularly among those segments of Serbian society that had been most supportive—or, alternatively, its decision to continue pursuing its own economic interests despite such awareness, underscores the profound flaws in the political communication it employed in this case. Full article

Biophotons are non-thermal and non-bioluminescent ultraweak photon emissions, first hypothesised by Gurwitsch as a regulatory mechanism in cell division, and then experimentally observed in living organisms. Today, two main hypotheses explain their origin: stochastic decay of excited molecules and coherent electromagnetic fields produced in biochemical processes. Recent interest focuses on the role of biophotons in cellular communication and disease monitoring. This study presents the first campaign of biophoton emission measurements from cultured astrocytes and glioblastoma cells, conducted at Fondazione Pisana per la Scienza (FPS) using two ultra-sensitive setups developed in collaboration between the National Laboratories of Frascati (LNF-INFN) and the University of Rome II Tor Vergata. The statistical analyses of the collected data revealed a clear separation between cellular signals and dark noise, confirming the high sensitivity of the apparatus. The Diffusion Entropy Analysis (DEA) was applied to the data to uncover dynamic patterns, revealing anomalous diffusion and long-range memory effects that may be related to intercellular signaling and cellular communication. These findings support the hypothesis that biophoton emissions encode rich information beyond intensity, reflecting metabolic and pathological states. The differences revealed by applying the Diffusion Entropy Analysis to the biophotonic signals of Astrocytes and Glioblastoma are highlighted and discussed in the paper. This work lays the groundwork for future studies on neuronal cultures and proposes biophoton dynamics as a promising tool for non-invasive diagnostics and the study of cellular communication. Full article

This work studies the formation control problem of general linear multi-agent systems (MASs) under hybrid attacks that include man-in-the-middle attacks (MITM) and denial-of-service attacks (DoS). First, an improved Diffie–Hellman key exchange (DHKE)-based encryption–decryption mechanism is proposed. This mechanism combines the challenge–response mechanism and hash function, which can achieve identity authentication, detect MITM attacks and ensure the confidentiality and integrity of information. Second, considering that DoS attacks on different channels are independent, a division model for distributed DoS attacks is established, which can classify attacks into different patterns. Third, an edge-based event-triggered (ET) formation control scheme is proposed. This control method only relies on the information of neighbor agents, which not only saves communication resources but also resists distributed DoS attacks. Finally, sufficient conditions for the implementation of formation control for MASs under hybrid attacks are provided, and the effectiveness and advantages of the proposed strategy are verified by simulation. Full article

The division of labor in mixed-gender couples has been a popular research topic for several decades, including discussions about household labor, childcare, and paid employment. However, few studies have examined these processes as they apply to highly religious couples, whose perspectives on labor division show some evidence of diverging from those who are less devout. To better understand how successful mixed-gender, highly religious couples from a broad range of faith traditions conceptualize the division of paid and unpaid labor, we employed a strengths-based, qualitative approach, examining data from 103 interviews with highly religious, highly satisfied couples (N = 206 participants). Viewed within an interdependence theory framework, findings across numerous religions and ethnicities revealed evidence of communal relationships, with themes emphasizing partnership, shared responsibility, and varied labor arrangements that required commitment, trust, and sacrifice. While spouses evidenced high levels of agreement with each other, a strong emphasis on a husband’s responsibility to provide financially contrasted with a more nuanced view of women’s roles, with some participants stressing women’s roles at home and some highlighting their right to choose employment and a more flexible household labor division. Difficulties mentioned revolved around traditional labor arrangements and work–life balance for husbands. Full article

Quantum communication presents new opportunities for overcoming the limitations of classical wireless systems, particularly those associated with noise, fading, and interference. Building upon the principles of classical orthogonal frequency division multi-plexing (OFDM), this work proposes a quantum OFDM architecture tailored for video transmission. In the proposed system, video sequences are first compressed using the versatile video coding (VVC) standard with different group of pictures (GOP) sizes. Each GOP size is processed through a channel encoder and mapped to multi-qubit states with various qubit configurations. The quantum-encoded data is converted from serial-to-parallel form and passed through the quantum Fourier transform (QFT) to generate mutually orthogonal quantum subcarriers. Following reserialization, a cyclic prefix is appended to mitigate inter-symbol interference within the quantum channel. At the receiver, the cyclic prefix is removed, and the signal is restored to parallel before the inverse QFT (IQFT) recovers the original quantum subcarriers. Quantum decoding, classical channel decoding, and VVC reconstruction are then employed to recover the videos. Experimental evaluations across different GOP sizes and channel conditions demonstrate that quantum OFDM provides superior resilience to channel noise and improved perceptual quality compared to classical OFDM, achieving peak signal-to-noise ratio (PSNR) up to 47.60 dB, structural similarity index measure (SSIM) up to 0.9987, and video multi-method assessment fusion (VMAF) up to 96.40. Notably, the eight-qubit encoding scheme consistently achieves the highest SNR gains across all channels, underscoring the potential of quantum OFDM as a foundation for future high-quality video transmission. Full article

Mangrove ecosystems underpin coastal livelihoods and biodiversity in Mozambique, yet gendered patterns of resource use and their implications for management remain underexplored. This study explores how artisanal fishing and shellfish collection differ between men and women on Inhaca Island (Maputo Bay), focusing on how these gender-specific practices shape livelihood outcomes, spatial use of mangroves, and perceptions of ecological change. To address this question, we combined structured interviews (n = 35; 51.4% men, 48.6% women) and camera-trap monitoring in two mangrove areas during September 2024 to document fishing practices, catch characteristics, spatial patterns, and ecological perceptions. We found pronounced gendered divisions of labor and space use: men, using boats and nets, harvested a median of 15 kg of fish per day for commercial sale, generating cash income, whereas women collected a median of 3 kg of shellfish by hand, primarily for household consumption. Camera traps confirmed pronounced spatial segregation in mangrove use: women foraged in targeted areas, and men traversed broader zones, both synchronizing their activities with tidal and daylight cycles. By integrating social and ecological data, the study revealed nuanced gender roles and resource pressures, with 82.9% of participants reporting declines in fish and shellfish stocks, emphasizing mangroves’ critical role in livelihoods, biodiversity, and climate resilience. Our findings highlight the value of mixed-method approaches for understanding socio-ecological dynamics and advocate for gender-sensitive conservation policies, strengthened Community Fisheries Councils, and infrastructure investments to regulate resource use, enhance mangrove management, and promote equitable livelihoods in Mozambique’s coastal communities. Full article

To date, there is extensive scientific evidence affirming that physical exercise plays a fundamental role in both the prevention and treatment of various pathological conditions in humans as well as in animals. It is understood that the advantages of movement and exercise have a multifactorial origin and they depend on a category of bioactive molecules vehicolated by extracellular microvesicles known as exosomes. The exosomes act as potential delivery systems for messages within the organism. These findings have drawn significant attention, leading researchers to further investigate the role of exosomes, delving into the study of microRNAs (miRNAs). In particular, these molecules are found inside exosomes and play a key role in cellular communication, with an impact on numerous physiological functions of the organism. It has been suggested that during physical exercise, the expression levels of miRNAs increase in parallel with those of exosomes, and their release enables intercellular communication in multicellular organisms, thereby regulating both cell growth and division. Studies have not only been carried out in humans, but also in laboratory animals and in mammals following exercise. Specifically, a change in exosome expression has been found in athletic horses following physical exercise. The aim of the current review was to highlight what is known about the role played by exosomes and miRNAs during physical exercise in equine species by considering, on a broad scale, the published data on this topic, including comparative data from humans and rodent models. Full article

This study examines the impact of Kosovo’s matrimonial property and inheritance laws on intergenerational inheritance and family connections. It explores how the division of property during marriage or upon divorce influences inheritance outcomes and the continuity of family lineage. The research employs a comparative approach, including genealogical case studies, to analyze these effects. Findings demonstrate that legal provisions significantly influence the preservation of family property and help prevent intra-family disputes. Well-structured laws ensuring the participation of children and the surviving spouse promote gender and social equality, respect heirs’ rights, and support economic sustainability. Comparative experiences from Germany and France offer practical examples for harmonizing property management in Kosovo. Additionally, the study highlights the importance of accurate property data and the use of genealogical records to maintain continuity in material inheritance and the construction of family history. Overall, matrimonial property and inheritance laws are more than legal instruments; they uphold social order and safeguard families’ material legacies. The study concludes with concrete recommendations for policy and legal practices that address communities’ real needs while acknowledging family history. Full article

This paper examines how entrenched dichotomies between natural/cultural and tangible/intangible heritage shape conservation policy in contexts where material, ecological, and socio-cultural dimensions are deeply interdependent. Despite calls for more integrated frameworks, limited empirical research examines how such categorical divisions operate within living rural heritage environments or how they align with community perspectives and inform conservation policies. This paper addresses this gap by analysing the persistence of rigid heritage taxonomies in officially designated traditional villages in central rural Greece exploring how heritage officials and residents perceive and value their heritage. Drawing on qualitative fieldwork across six villages—including interviews, focus groups, and consultations with heritage professionals—it demonstrates that these categorical divisions fail to reflect local understandings of heritage as a living socio-ecological system. For residents, ecological conditions, built forms, agricultural practices, and social relations are interdependent and tied to livelihoods, land stewardship, and communal identity. Findings show that the Authorized Heritage Discourse (AHD) reinforces artificial separations that are misaligned with grassroots perceptions and hinder integrated planning. This mismatch has direct implications for sustainability: governance models that fragment nature, culture, and community obscure socio-ecological processes and limit the development of meaningful sustainability strategies. By foregrounding experiential and affective dimensions of heritage, the paper advances debates on community-centred and context-responsive heritage management. It reframes rural heritage as a co-produced, evolving system of material, social, and ecological relations, positioning rural landscapes as critical arenas for addressing sustainability challenges and offering new empirical insights into an underexplored dimension of heritage research. The study further advocates for governance approaches that embed local ontologies and lived knowledge into policy and practice, fostering more inclusive, resilient, and socio-ecologically grounded heritage frameworks capable of supporting long-term sustainable development. Full article

In optical receiver mode (ORM) division multiplexing optical communication systems, which can ultimately achieve a very high spectral efficiency, an accurate evaluation of the ORMs is crucial. Conventionally, to find the mode functions and the eigenvalues of ORMs, we have to solve an integral equation numerically. Here, we introduce a new method that solves a Schrödinger equation instead. This method assumes that the optical receiver uses an optical Fabry–Perot filter to select an optical channel from the received optical channels. The time-reversed impulse response of the optical receiver’s electrical filter is proportional to the potential in the Schrödinger equation. We show two potential cases that have exact solutions. One is the square-well potential case and the other is the exponential-well potential case. Full article

To address the challenges of improving energy balance and extending the operational lifetime of wireless sensor networks for Automated Railway Track Fastener Maintenance Robots (ARTFMR) along railways, this paper proposes an enhanced LEACH protocol incorporating Particle Swarm Optimization (PSO). Initially, network nodes are deployed, and their energy consumption is calculated to formulate a non-uniform deployment model aimed at improving energy balance, followed by network clustering. Subsequently, a routing protocol is designed, where the cluster head election mechanism integrates two critical factors—dynamic residual energy and distance to the base station—to facilitate dynamic and distributed cluster head rotation. During the communication phase, a Time Division Multiple Access (TDMA) scheduling mechanism is employed in conjunction with an inter-cluster multi-hop routing scheme. Additionally, a joint data-volume and energy optimization strategy is implemented to dynamically adjust the transmission data volume based on the residual energy of each node. Finally, simulations were conducted using MATLAB, and the results indicate that the proposed energy-balanced non-uniform deployment optimization strategy improves network energy utilization, effectively extends network lifetime, and exhibits favorable scalability. Full article

Visible Light Communication (VLC) systems commonly employ optical orthogonal frequency division multiplexing (O-OFDM) to achieve high data rates, benefiting from its robustness against multipath effects and intersymbol interference (ISI). However, a key limitation of asymmetrically clipped direct current biased optical–OFDM (ACO-OFDM) systems lies in their inherently high peak-to-average power ratio (PAPR), which significantly affects signal quality and system performance. This paper proposes a joint chaotic encryption and modified μ-non-linear logarithmic companding (μ-MLCT) scheme for ACO-OFDM–based VLC systems to simultaneously enhance security and reduce PAPR. First, image data is encrypted at the upper layer using a hybrid chaotic system (HCS) combined with Arnold’s cat map (ACM), mapped to quadrature amplitude modulation (QAM) symbols and further encrypted through chaos-based symbol scrambling to strengthen security. A μ-MLCT transformation is then applied to mitigate PAPR and enhance both peak signal-to-noise ratio (PSNR) and bit-error-ratio (BER) performance. A mathematical model of the proposed secured ACO-OFDM system is developed, and the corresponding BER expression is derived and validated through simulation. Simulation results and security analyses confirm the effectiveness of the proposed solution, showing gains of approximately 13 dB improvement in PSNR, 2 dB in BER performance, and a PAPR reduction of about 9.2 dB. The secured μ-MLCT-ACO-OFDM not only enhances transmission security but also effectively reduces PAPR without degrading PSNR and BER. As a result, it offers a robust and efficient solution for secure image transmission with low PAPR, making it well-suitable for emerging wireless networks such as cognitive and 5G/6G systems. Full article

For XL-MIMO multi-user frequency division duplex systems, this paper proposes a near-field beam training scheme using a two-phase combinatorial multi-armed bandit (MAB) framework. This scheme leverages the MAB framework, integrating energy-aware user scheduling and hierarchical beam training to balance communication quality and device battery level, thereby effectively enhancing system energy efficiency and extending the device’s lifespan. Specifically, in the first phase, we account for user battery levels by designing an energy-aware upper confidence bound (UCB) algorithm for user scheduling. This algorithm effectively balances exploration and exploitation, prioritizing users with higher achievable rates and sufficient battery level. In the second phase, based on the scheduled users, two UCB algorithms are employed for beam training. In the first layer, discrete Fourier transform codebook-based beam scanning is utilized, and a UCB algorithm is applied to initially acquire angle information for scheduled users. In the second layer, based on the obtained angle information, a candidate set of polar-domain codewords is constructed. Another UCB algorithm is then employed to select the optimal polar-domain codewords. The effectiveness of our scheme is confirmed by simulations, demonstrating notable achievable rate gains for multi-user communications. Full article