Search Results (2,832)

We consider a secure integrated sensing and communication (ISAC) scenario, where a signal is transmitted through a state-dependent wiretap channel with one legitimate receiver with which the transmitter communicates and one honest-but-curious target that the transmitter wants to sense. The secure ISAC channel is modeled as two state-dependent fast-fading channels with correlated Rayleigh fading coefficients and independent additive Gaussian noise components. Delayed channel outputs are fed back to the transmitter to improve the communication performance and to estimate the channel state sequence. We establish and illustrate an achievable secrecy-distortion region for degraded secure ISAC channels under correlated Rayleigh fading, for which we show that the signal-to-interference-plus-noise is not a sufficient statistic. We also evaluate the inner bound for a large set of parameters to derive practical design insights. The presented results include parameter ranges for which the secrecy capacity of a classical wiretap channel setup is surpassed and for which the channel capacity is approached. Thus, we illustrate for correlated Rayleigh fading cases that our secure ISAC methods can (i) eliminate the need for the legitimate receiver to have a statistical advantage over the eavesdropper and (ii) provide communication security with minimal rate penalty. Full article

Although large language models (LLMs) like the Generative Pre-trained Transformer (GPT) are growing increasingly popular, much remains to learn about their potential for website quality auditing. The article evaluates the performance of LLM AI plugins (GPT models) in website and web application auditing. The author built and tested two original ChatGPT-4o Plus (OpenAI) plugins: Website Quality Auditor (WQA) and WebGIS Quality Auditor (WgisQA). Their performance was cautiously and carefully analysed and compared to traditional auditing tools. The results demonstrated the limitations of the AI plugins, including their propensity for false outcomes. The general conclusion is that using AI tools without considering their characteristics may lead to the propagation of AI hallucinations in audit reports. The study fills in the research gap with the results on the capabilities and limitations of AI plugins in the context of auditing. It also suggests further directions for improvement. Full article

Identifying ecological functional areas by clarifying the trade-off synergies of multiple ecosystem services to meet the practical needs of coordinating different ecosystem services in a specific region is highly important. Based on InVEST, RUSLE and other models, this study analyzed the tradeoff synergies of five typical ecosystem services in the Wanjiang Urban Belt from 1990 to 2020 using Pearson correlation analysis, and self-organizing map (SOM) carried out ecological functional zoning. The PLUS model was used to simulate the evolution of ecological functional zones in 2030. The results revealed that (1) from 1990 to 2020, water yield (WY), soil reservation (SR), and food production (FP) services in Wanjiang Urban Belt increased, whereas carbon storage (CS) and habitat quality (HQ) services decreased. The value of ecosystem services showed a pattern of “high in the south and low in the north”. (2) WY–SR, WY–HQ, HQ–CS, and HQ–SR were synergistic, and the synergistic relationship showed a weakening trend. There were trade-offs in WY–CS, WY–FP, and SR–FP, and the trade-off effects increased with time. (3) The study area was divided into an ecological transition area, an ecological conservation area, an urban development area, an ecological restoration area, an agroecological area, and a water conservation area, and the functions and structures of each cluster significantly differed. (4) Under the natural development scenario, the scales of the ecological transition, ecological conservation, and agroecological areas increased. Under the cropland protection scenario, the urban development and ecological conservation areas began to transform into agroecological areas. Under the urban development scenario, the transfer of areas from ecological conservation, ecological restoration, and agroecological areas to urban development areas increased. In conclusion, the ecosystem services of the Wanjiang Urban Belt are dominated by synergistic effects, but there is a potential risk of shifting to trade-off relationships. In the future, targeted regional ecosystem optimization measures according to the evolution status of each ecological functional zone are urgently needed to provide references for territorial space management and control in this region. Full article

Background/Objective: The association of body mass index (BMI) with long-term outcomes following percutaneous coronary intervention (PCI) remains poorly investigated. We undertook this study to assess the association between BMI and long-term outcomes after PCI. Methods: Overall, 5597 patients with coronary artery disease undergoing PCI were included in the study. Patients were categorized in groups according to the following BMI categories: underweight group (BMI <18.5 kg/m²), normal weight group (BMI 18.5 kg/m² to <25 kg/m²), overweight group (BMI 25 kg/m² to <30 kg/m²) and obesity group (BMI ≥30 kg/m²). The primary endpoint was all-cause mortality at 10 years. Results: At 10 years, all-cause deaths (primary endpoint) occurred in 1754 patients: 31 deaths (59.7%) in the underweight group, 582 deaths (39.1%) in the normal weight group, 710 deaths (31.1%) in the overweight group and 431 deaths (33.8%) in the obesity group (overall p < 0.001; p for nonlinearity <0.001). Nonsurvivors had a significantly lower BMI compared with survivors (26.5 [24.2–29.9] kg/m² vs. 27.2 [24.8–30.1] kg/m², p < 0.001). Interaction testing showed a BMI-by-age interaction denoting a stronger association between higher BMI (≥25 kg/m²) and reduced risk of all-cause mortality in patients ≥75 years of age (P_int = 0.009). The association of BMI with all-cause mortality was U-shaped (p for nonlinearity < 0.001). The C-statistic of the multivariable Cox proportional hazards model for mortality increased from 0.762 [0.751–0.773] with baseline variables only to 0.766 [0.756–0.777], p < 0.001) after the BMI inclusion in the model (baseline variables plus BMI). Conclusions: In patients with coronary artery disease undergoing PCI, BMI was associated with 10-year mortality with a U-shaped relationship. Full article

Power line communication (PLC) technology is investigated in this research. A PLC system model combining Orthogonal Frequency Division Multiplexing (OFDM) and Non-Orthogonal Multiple Access (NOMA) technologies is proposed to enhance spectral efficiency, extend transmission distance, and improve signal quality. We construct detailed models for the system, signal, and noise. Future Channel State Information (CSI) is predicted using a Long Short-Term Memory (LSTM) network, and an improved simulated annealing algorithm is employed to optimize power allocation and relay positioning in the system. Experiments validate the effectiveness of the LSTM model in predicting CSI data in a NOMA communication system, demonstrating generally good performance despite some prediction errors. Simulation results show that this approach significantly enhances system performance, reduces power consumption, and meets constraints on system capacity, bit error rate (BER), and signal-to-interference-plus-noise ratio (SINR) in complex PLC environments. Future research should focus on optimizing model parameters, expanding datasets, exploring alternative optimization algorithms, and testing the model in real-world scenarios to improve generalizability and practicality. In conclusion, the proposed multi-user PLC system provides an effective technical solution for future smart grid and Internet of Things (IoT) applications. Full article

The Yellow River Basin (YRB) serves as a critical ecological functional and economic zone in China. However, due to the rapid economic and social development, the YRB has encountered dual pressure from the anthropogenic disturbances and climate change, leading to intensified conflicts among production, living, and ecological spaces (PLES). In this study, we examined the spatiotemporal evolution pattern and transition mode of the PLES from 1980 to 2020 at the county level, evaluated the eco-environmental effects, and identified the key driving factors. The results indicate that land-use changes in the YRB are marked by a continuous increase in living space, while ecological spaces initially decreased before increasing, and production spaces initially increased before decreasing, with the year 2000 serving as a pivotal point in these transitions. At the county level, land-use transformations in the YRB have significant spatial differentiation. The north region of the Hu Line is predominantly characterized by a reduction in ecological space, whereas the south primarily exhibits declines in production space and increases in living space in the downstream region. Consequently, the environmental quality index (EQI) also exhibits a trend of an initial decline followed by an increase. Frequent mutual conversions between production and ecological spaces influenced by major national ecological conservation policies after 2000, as well as pressure from living spaces on production spaces influenced by population and GDP growth, have been the primary manifestations of spatial transformation in the region. These findings suggest that with the implementation of appropriate governance measures, exploring the transformation of PLES at a finer county level can provide a clearer pattern of spatiotemporal changes, supporting detailed basin management for sustainable development. Full article

One of the most important contributions of modern control theory from the 1960s was the separation of the dynamics of state-space controller design from the dynamics of state reconstruction. However, because modern control theory predates the mass spread of digital controllers and was predominantly focused on analog solutions that avoided modeling dead-time elements, it cannot effectively cover all aspects that emerged with the development of programmable devices and embedded systems. The same historical limitations also characterized the development of proportional-integral-derivative (PID) controllers, which began several decades earlier. Although they were used to control time-delayed systems, these solutions, which are most commonly used in practice today, can also be referred to as simplified disturbance observers that allow the avoidance of the the direct use of dead-time models. Using the example of controlling systems with a double integrator plus dead-time model, this article shows a novel controller design that significantly improves control performance compared to conventional PID controllers. The new control structure is a combination of a generalized state-space controller, interpreted as a higher-order derivative controller, and a predictive disturbance observer that uses the inversion of double integrator dynamics and dead-time models. It enables the elimination of the windup effect that is typical for PID control and extends the separation of the dynamics of setpoint tracking from the dynamics of state and disturbance reconstruction to time-delayed processes as well. The novelty of the presented solution offers several orders of magnitude lower amplification of measurement noise compared to traditional PID control. On the other hand, it offers high robustness and a stable transient response despite the unstable internal feedback of processes like the magnetic levitation system. The improvements achieved are so high that they call into question the classical solutions with PID controllers, at least for DIPDT models. In addition to the comparison with PID control, the relationship with traditional state space controllers, which today form the basis of active disturbance rejection control (ADRC), is also discussed and examined for processes including dead time. Full article

Background/Objectives: Bacteria are becoming increasingly resistant to levofloxacin and other fluoroquinolones. Previously, drug loading in colloidal carriers has shown enhanced penetration into and retention in bacterial cells. However, the mechanism of levofloxacin niosomes’ bio-disposition in rats has not been reported. This study investigated the pharmacokinetics (PK) of optimized levofloxacin niosomes following intraperitoneal injection into Sprague Dawley rats. Methods: Formulation and processing variables settings were determined using DoE Fusion One software. The resulting data input into the Optimizer module provided niosome formulation for in vivo study in Sprague Dawley rats. Each group of rats (n = 6) was injected intraperitoneally with either conventional levofloxacin or its niosomes at equivalent doses of 7.5 mg/kg/dose. Blood samples were collected via tail snip and analyzed using a validated HPLC method. The plasma–time data were fed into the Gastroplus software (Simulations Plus, CA) and used to model levofloxacin PK. Results: Niosomes for in vivo study had a mean hydrodynamic diameter of 329.16 nm (±18.0), encapsulation efficiency (EE) of 30.74%, Zeta potential of 21.72 (±0.54), and polydispersity index (PDI) of 0.286 (±0.014). Both the Akaike and Schwarz criteria showed levofloxacin niosomes and conventional drug formulation obeying one- and two-compartment PK models, respectively. Thus, formulation in niosomes altered levofloxacin biodistribution by concentrating the drug in the vascular compartment. Conclusions: Niosome encapsulation of levofloxacin altered its biodistribution and pharmacokinetic profile, possibly by protecting i.p. levofloxacin en route into plasma, and significantly enhanced its plasma concentration with enhanced potential for treating intravascular infections. Full article

As an important gateway for China’s foreign exchanges, the border areas of Guangxi face irrational land use issues that impact local ecology, the economy, national security, and international relations. With global attention on climate change, “carbon peaking”, “carbon neutrality”, and ecosystem carbon storage, this study focuses on the border area, using natural resource, socio-economic, and transportation factors. Through the PLUS and In VEST models, it predicts carbon storage under multiple scenarios. (1) The results show that from 2000 to 2020, forest land, water bodies, and other land types decreased, while construction land and cropland increased. Land use changes accelerated over time, with significant urban expansion into cropland and forest areas, reflecting rapid socio-economic development. (2) For 2030, the following projections were made: Under natural development, construction land expands significantly, forest land declines, and urbanization spreads outward. Under urban development, construction land grows fastest, forest and grassland decline sharply, and infrastructure reduces other land types. Under sustainable development, reductions in forest and grassland are mitigated, construction land grows moderately, and water bodies remain stable, achieving a balance between humans and nature. (3) Compared to 2020, ecosystem carbon storage declines across scenarios. Annual decreases are 513,223.13 tons (natural), 5,469,327.95 tons (urban), and 500,214.24 tons (sustainable). Sustainable development is crucial for achieving “dual carbon” goals. This study emphasizes ecological priority, strict cropland protection, and controlled construction land, offering sustainable land management strategies to ensure rational land use and border security. Full article

In this paper, we consider the issue of the physical layer security (PLS) problem between two nodes, i.e., transmitter (Alice) and receiver (Bob), in the presence of an eavesdropper (Eve) in a near-field communication (NFC) system. Notably, massive multiple-input multiple-output (MIMO) arrays significantly increase array aperture, thereby rendering the eavesdroppers more inclined to lurk near the transmission end. This situation necessitates using near-field channel models to more accurately describe channel characteristics. We consider two schemes with imperfect channel estimation information (CSI). The first scheme involves a conventional multiple-input multiple-output multiple-antenna eavesdropper (MIMOME) setup, where Alice simultaneously transmits information signal and artificial noise (AN). In the second scheme, Bob operates in a full-duplex (FD) mode, with Alice transmitting information signal while Bob emits AN. We then jointly design beamforming and AN vectors to degrade the reception signal quality at Eve, based on the signal-to-interference-plus-noise ratio (SINR) of each node. To tackle the power minimization problem, we propose an iterative algorithm that includes an additional constraint to ensure adherence to specified quality-of-service (QoS) metrics. Additionally, we decompose the robust optimization problem of the two schemes into two sub-problems, with one that can be solved using generalized Rayleigh quotient methods and the other that can be addressed through semi-definite programming (SDP). Finally, our simulation results confirm the viability of the proposed approach and demonstrate the effectiveness of the protection zone for NFC systems operating with CSI. Full article

Most of the processes with various dynamic characteristics can be reduced to the Second Order Plus Time Delay (SOPTD) model by using the model reduction method. We propose a novel hybrid approach that combines Long Short-Term Memory (LSTM)-based real-time model identification with Genetic Algorithms to enhance the Smith predictor control structure. This method compensates for the delay time of the SOPTD model while minimizing the Integral Time Absolute Error performance index. Our approach integrates an optimally adaptive Proportional–Integral–Derivative (PID) controller design algorithm that estimates the coefficients of the SOPTD model in the Smith Predictor control structure and adjusts the PID controller parameters dynamically. The method is improved through a combination of numerical calculation, Genetic Algorithms, and LSTM networks, showing approximately 15% better performance compared to conventional methods. The system demonstrates significant improvements in both performance metrics and resource utilization, including a 40% reduction in execution time and enhanced resource efficiency. Simulation results show that the proposed scheme exhibits improved adaptability to disturbances and process variations, with faster response times and reduced overshoots compared to traditional methods. The steady-state response of the higher-order model and the reduced model shows perfect matching for the unit feedback input. Full article

The increasing concern over greenhouse gas emissions, particularly CO₂, has emphasized the urgency for practical solutions to mitigate the environmental impacts of climate change. This study assessed the technical, economic, and environmental feasibility of producing dimethyl carbonate (DMC) through an integrated route using methanol derived from biomass gasification in sugarcane-based industries. Unlike previous studies that analyzed isolated aspects of DMC production, this research was conducted through process modeling and simulation in Aspen Plus^® V12.1, evaluating key performance indicators such as conversion rates, product purity, capital and operating expenses, and CO₂ emissions. A DMC conversion rate of 78.06% and a purity level of 96.80% were achieved. However, the integration of methanol production increased both CAPEX and OPEX, leading to a net present value (NPV) of R$ 36.7 million over 10 years, lower than alternative routes using commercially available methanol. Additionally, the process resulted in a net CO₂ emission of 3.41 kg CO₂ per kg of DMC, exceeding conventional methods. These findings suggest that under the evaluated conditions, process integration did not offer economic advantages, despite many environmental advantages over commercially available methanol. Full article

As urbanization accelerates, megacities are facing challenges such as inefficient land use and traffic congestion, particularly in the context of rail transit-oriented development, where land use optimization remains a significant research gap. Current urban planning still relies heavily on the experience and intuition of government planning departments, without achieving quantitative, intelligent, and scientific decision making. This study takes Panda Avenue Subway Station as a case study to analyze the evolution of land use patterns around subway stations and explore optimization strategies to enhance land development efficiency and spatial utilizationTo fill this research gap, this paper proposes a CNN-AIMatch model based on machine learning algorithm and an enhanced PLUS-Markov prediction model using the increase and decrease of floor area ratio as a control measure, which adopts an increase in plot ratio as a control measure to improve the accuracy of the Kappa coefficient in different plot ratio scenarios and the prediction of 3D urban spatial growth trends. The model effectively overcomes the limitations of the conventional 2D perspective in predicting urban expansion. By simulating urban renewal and ecological preservation scenarios, it provides an innovative solution for land use pattern optimization and plot ratio control at the block level in subway station areas. The goal of this study is to optimize land use and floor area ratio control strategies through the application of this model, intelligently respond to the challenges of high-density development and quality of life assurance, achieve the best use of land, and promote sustainable urban development and the construction of smart cities. Full article

Urbanization and economic growth have substantially modified the land utilization structure, affecting ecosystem services and their spatial distribution. As a crucial component of Beijing’s urban framework, the city’s green belts, located at the periphery of its core metropolitan area, play a vital role in supplying urban ecosystem services. They also represent a focal point for land use transformation conflicts, making them an important study area. This research utilizes land utilization data from 2000, 2005, 2010, 2015, and 2020 as the primary dataset. It adopts a modified standard equivalent factor and integrates it with the Patch-Generaling Land Use Simulation (PLUS) model to model land utilization in Beijing’s green belts for 2035 under three scenarios: the natural development scenario (NDS), ecological protection scenario (EPS) and cultivated protection scenario (CPS). The study aims to analyze and project the spatial and temporal evolution of ecosystem service values (ESVs) in 2035 under different scenarios in the green belts of Beijing. The results indicate that (1) land use in Beijing’s green belts is dominated by cropland and construction land. Construction land has expanded significantly since 2000, increasing by 500.78 km², while cropland has decreased by 488.47 km². Woodland, grassland, and water have also seen a reduction. Overall, there is a trend of woodland and water being converted into cropland, with cropland subsequently transitioning into construction land. (2) In the NDS, construction land increases by 91.76 km², while cropland, grassland, and water decrease. In EDS, the growth of construction land decelerates to 22.09 km², the reduction in cropland decelerates, and the conversion of cropland to construction land is limited. Grassland and water remain largely unchanged, and woodland experiences a slight increase. In CPS, the conversion of cropland to construction land is notably reduced, with construction land increasing by 11.97 km², woodland increasing slightly, and grassland and water decreasing slightly. (3) The ESV ranking across scenarios is as follows: EPS 1830.72 mln yuan > CPS 1816.23 mln yuan > NDS 1723.28 mln yuan. Hydrological regulation and climate regulation are the dominant services in all scenarios. ESV in EPS attains the greatest economic gains. This study contributes to understanding the effects of land utilization changes on ESV, offering valuable empirical evidence for sustainable development decision-making in swiftly urbanizing areas. Full article

This study analyzes, quantifies, and maps, from a bibliometric perspective, scientific production, bioeconomy and computational simulations regarding avocado use in the timeframe of 2004–2023 in Scopus. To categorize and evaluate the contributions of authors, countries, institutions, and journals, Biblioshiny software in RStudio was used. Their collaborative networks were also visualized using VOSviewer. The analysis reveals an exponential increase in scientific output, especially from 2019 onwards, driven by the growing importance of sustainable avocado use in bioeconomy models. The main findings highlight the valorization of avocado waste for producing biofuels, cosmetics, pharmaceuticals, and food. In addition, the use of computational tools such as Aspen Plus, ArcGIS Pro, Unscrambler-X, SIMCA, and DOCK-6 to optimize conversion processes, model climate change effects, perform chemometrics, and conduct multivariate analyses, and molecular docking, respectively, is discussed. This knowledge highlights potential uses of avocado waste and computational modeling tools for stakeholders in the avocado industry, reinforcing their value chain through bioeconomy models and strengthening their competitiveness by promoting more efficient and sustainable processes. This work provides a comprehensive overview of the avocado-based bioeconomy, serving as a reference for future studies that integrate process simulation in the valorization of agro-industrial waste. Full article