Search Results (9)

The European Union’s Artificial Intelligence Act (EU AI Act) is expected to be a major legal breakthrough in an attempt to tame AI’s negative aspects by setting common rules and obligations for companies active in the EU Single Market. Globally, there is a surge in investments to encourage research, development and innovation in AI that originates both from governments and private firms. The EU recognizes that the new Regulation (EU) 2024/1689 is difficult for start-ups and SMEs to cope with and it announced the release of tools, in the near future, to ease that difficulty. To facilitate the active participation of SMEs in the AI arena, we propose a framework that could assist them to better comply with the challenging EU AI Act during the development life cycle of an AI system. We use the spiral SDLC model and we map its phases and development tasks to the legal provisions of Regulation (EU) 2024/1689. Furthermore, the framework can be used to promote innovation, improve their personnel’s expertise, reduce costs and help the companies avoid the proposed substantial fines described in the Act. Full article

The multi-objective path planning and robust continuous path-following method for the autonomous marine surface vehicle (AMSV) is employed. By incorporating the position and direction constraints into the optimization cost function, the spiral path planner obtains a continuous path with smooth path tangency and curvature and ensures strict adherence to the desired multi-objective points. An improved A* and optimization algorithm are combined with the global path planning to avoid obstacles in real-time. For the path-following controller, the unknown sideslip angle and uncertainties are added to build the system model, based on which observation technique is adopted to estimate all the uncertainties online. Based on the kinematic system, a finite time extended state observer (ESO) is put forward to estimate the sideslip angle accurately. The nonlinear line-of-sight (LOS) guidance scheme is designed for the model, effectively compensating for the observed values and achieving convergence in a finite time. The finite-time ESO is adopted to estimate the uncertainty for the surge and heading controller design, and the terminal sliding mode technique is introduced to achieve the final finite-time convergence. Through extensive experiments, the proposed approach demonstrates its effectiveness, feasibility, and the advantage of fast convergence and accurate control. Full article

Pumped storage power is considered an ideal regulated power source for new energy. However, the traditional one-dimensional characteristic line method cannot predict the pulsating pressure caused by the reverse “S” characteristic of a pump–turbine. In this paper, a variable-step Euler algorithm is presented to calculate the hydraulic transient process of pumped storage units, the interval times of start-up and load regulation between two pump–turbine units are investigated by using the method of peak staggering and valley filling, and the closure law of guide vanes in the transient process of load rejection is optimized. The results show that the presented method is valid, and that pulsating pressure is accurately captured during the transient process of load rejection. The water level fluctuation amplitude in the surge chamber is greatly reduced by the sequential start-up mode. The rotational speed fluctuation amplitude of the sequential load reduction is also reduced. After the load of two pump–turbine units is rejected at the same time, the duration of pulsating pressure in the spiral case is shortened by 45% by using the quick-then-slow closure law compared with the straight-line closure law. Moreover, the pulsating pressure amplitude and the second peak value of rotational speed are also reduced accordingly, and the transient characteristics of the pump–turbine units are greatly improved. Full article

Drawing on data from 133 Chinese New Energy Vehicle (NEV) policy documents from 2007 to 2023, this study utilizes Dynamic Topic Modelling (DTM), social network analysis and a quantitative model to investigate the evolutionary path of policy themes and the coordination effects. The following results were obtained. (1) A thematic cross-sectional analysis identified six core policy themes, namely, coordinated promotion of technology and finance, industry development and safety standardisation, market service and technical support systems, promotion strategy and urban cluster development, industrial capital and safety supervision mechanisms, and policy support and market expansion. The analysis also mapped the distribution of hot spots within these themes. (2) The keyword co-occurrence network of the NEV policy indicated that the network structure evolved from an initial ‘overall dispersion–theme concentration’, comprising 16 policy themes, to an ‘overall stability–theme coordination’, consisting of 14 policy themes. (3) The coordination degrees across the three types of policies exhibited a consistent upward spiral, with the comprehensive coordination index surging from 30 in 2007 to 951 in 2023, underscoring the complementary effects among policy instruments. These conclusions offer valuable insights for government departments to understand NEV development trends and dynamically adjust policy themes accordingly. Full article

The employment of a multi-column parallel connection is intended to enhance the energy absorption capability and reliability of surge arresters. However, the disparity in reference voltage between each varistor column and the uneven current distribution may result in a reduction in performance or even failure of the surge arrester. The objective of this study is to investigate the spiral structure of a ±550 kV DC gas-insulated switchgear (GIS) parallel arrester and its influence on the current distribution characteristics. This research develops a model of a ±550 kV DC GIS arrester and performs an in-depth theoretical analysis using multi-physics field simulations. Subsequently, a ±66 kV miniature prototype is constructed, and the accuracy of the theoretical analysis and simulation results is validated by experiments, validating the effectiveness of the proposed method. This study calculates the self-generated inductance in the spiral structure of ZnO varistors using simulations. The influence of the self-generated inductance on the current distribution of the multi-column arrester when absorbing energy is further investigated. The results indicate that the self-generated inductance of the spiral structure can reduce the current deviation factor by 28–65%. This research provides a novel approach to improving current equalization in the parallel surge arresters of DC GISs for offshore wind power converter platforms. Full article

The availability of sugar has expanded over the past 50 years, due to improved industrial processes and corn subsidies, particularly in the form of sweetened beverages. This correlates with a surge in the prevalence of cardiometabolic disorders, which has brought this issue back into the spotlight for public health. In this narrative review, we focus on the role of fructose in the genesis of cardiometabolic dyslipidemia (an increase in serum triglyceride-rich lipoproteins (TRL): VLDL, chylomicrons (CM), and their remnants) bringing together the most recent data on humans, which demonstrates the crucial interaction between glucose and fructose, increasing the synthesis while decreasing the catabolism of these particles in a synergistic downward spiral. After reviewing TRL metabolism, we discuss the fundamental principles governing the metabolism of fructose in the intestine and liver and the effects of dysregulated fructolysis, in conjunction with the activation of carbohydrate-responsive element-binding protein (ChREBP) by glucose and the resulting crosstalk. The first byproduct of fructose catabolism, fructose-1-P, is highlighted for its function as a signaling molecule that promotes fat synthesis. We emphasize the role of fructose/glucose interaction in the liver, which enhances de novo lipogenesis, triglyceride (TG) synthesis, and VLDL production. In addition, we draw attention to current research that demonstrates how fructose affects the activity of lipoprotein lipase by increasing the concentration of inhibitors such as apolipoprotein CIII (apoCIII) and angiopoietin-like protein 3 (ANGPTL3), which reduce the catabolism of VLDL and chylomicrons and cause the building up of their atherogenic remnants. The end outcome is a dual, synergistic, and harmful action that encourages atherogenesis. Thus, considering the growing concerns regarding the connection between sugar consumption and cardiometabolic disease, current research strongly supports the actions of public health organizations aimed at reducing sugar intake, including dietary guidance addressing “safe” limits for sugar consumption. Full article

Transient analysis in diversion pipelines should be performed to ensure the safety of a hydropower system. After the establishment of a three-dimensional (3D) geometric model from the part upstream reservoir to the diversion pipeline end in a pumped storage hydropower (PSH) station, the hydraulic characteristics of the diversion system were solved by Reynold average Navier–Stokes (RANS) equations based on a volume of fluid (VOF) method under the condition of simultaneous load rejection of two units. The variations of the water level in the surge tank, the pressure at the pipeline end, and the velocity on the different pipeline sections with time were obtained through the calculation. The numerical results showed that the water level changing in the surge tank simulated by VOF was consistent with the field test data. These results also showed that a self-excited spiral flow occurs in the pipeline when the flow at the end of the pipeline was reduced to zero and its intensity decreased with the flow energy exhaustion. The discovery of the self-excited spiral flow in the study may provide a new explanation for the pressure wave attenuation mechanism. Full article

Hydropower plays a key role in the actual energy market due to its fast response and regulation capacity. In that way, hydraulic turbines are increasingly demanded to work at off-design conditions, where complex flow patterns and cavitation appear, especially in Francis turbines. The draft tube cavitation surge is a hydraulic phenomenon that appears in Francis turbines below and above its Best Efficiency Point (BEP). It is a low frequency phenomenon consisting of a vortex rope in the runner outlet and draft tube, which can become unstable when its frequency coincides with a natural frequency of the hydraulic circuit. At this situation, the output power can significantly swing, endangering the electrical grid stability. This study is focused on the detection of these instabilities in Francis turbines and their relationship with the output power swings. To do so, extensive experimental tests for different operating conditions have been carried out in a large prototype Francis turbine (444 MW of rated power) within the frame of the European Project Hyperbole (FP7-ENERGY-2013-1). Several sensors have been installed in the hydraulic circuit (pressure sensors in the draft tube, spiral casing, and penstock), in the rotating and static structures (vibration sensors, proximity probes, and strain gauges in the runner and in the shaft), as well as in the electrical side (output power, intensity, and voltage). Moreover, a numerical Finite Element Method (FEM) has been also used to relate the hydraulic excitation with the output power swing. Full article

We consider chemical plume tracing (CPT) in time-varying airflow environments using multiple mobile robots. The purpose of CPT is to approach a gas source with a previously unknown location in a given area. Therefore, the CPT could be considered as a dynamic optimization problem in continuous domains. The traditional ant colony optimization (ACO) algorithm has been successfully used for combinatorial optimization problems in discrete domains. To adapt the ant colony metaphor to the multi-robot CPT problem, the two-dimension continuous search area is discretized into grids and the virtual pheromone is updated according to both the gas concentration and wind information. To prevent the adapted ACO algorithm from being prematurely trapped in a local optimum, the upwind surge behavior is adopted by the robots with relatively higher gas concentration in order to explore more areas. The spiral surge (SS) algorithm is also examined for comparison. Experimental results using multiple real robots in two indoor natural ventilated airflow environments show that the proposed CPT method performs better than the SS algorithm. The simulation results for large-scale advection-diffusion plume environments show that the proposed method could also work in outdoor meandering plume environments. Full article