Hasil untuk "Land use"

B. Turner, D. Skole, S. Sanderson et al.

J. Dupouey, E. Dambrine, Jean-Denis Laffite et al.

A. Veldkamp, E. Lambin

E. Irwin, J. Geoghegan

Lucie Sliva, D. Williams

Dawen Yang, S. Kanae, T. Oki et al.

H. Emre Tekaslan, Ella M. Atkins

This paper develops a real-time, search-based aircraft contingency landing planner that minimizes traffic disruptions while accounting for ground risk. The airspace model captures dense air traffic departure and arrival flows, helicopter corridors, and prohibited zones and is demonstrated with a Washington, D.C., area case study. Historical Automatic Dependent Surveillance-Broadcast (ADS-B) data are processed to estimate air traffic density. A low-latency computational geometry algorithm generates proximity-based heatmaps around high-risk corridors and restricted regions. Airspace risk is quantified as the cumulative exposure time of a landing trajectory within congested regions, while ground risk is assessed from overflown population density to jointly guide trajectory selection. A landing site selection module further mitigates disruption to nominal air traffic operations. Benchmarking against minimum-risk Dubins solutions demonstrates that the proposed planner achieves lower joint risk and reduced airspace disruption while maintaining real-time performance. Under airspace-risk-only conditions, the planner generates trajectories within an average of 2.9 seconds on a laptop computer. Future work will incorporate dynamic air traffic updates to enable spatiotemporal contingency landing planning that minimizes the need for real-time traffic rerouting.

M. Herold, H. Couclelis, K. Clarke

D. Foster, Glenn Motzkin, B. Slater

B. Scanlon, R. Reedy, D. Stonestrom et al.

Zhenyu Wei, Zhijiang Shao, Lorenz T. Biegler

Multiple parafoil landing is an enabling technology for massive supply delivery missions. However, it is still an open question to design a collision-free, computation-efficient guidance and control method for unpowered parafoils. To address this issue, this paper proposes a coordinated guidance and control method for multiple parafoil landing. First, the multiple parafoil landing process is formulated as a trajectory optimization problem. Then, the landing point allocation algorithm is designed to assign the landing point to each parafoil. In order to guarantee flight safety, the collision-free trajectory replanning algorithm is designed. On this basis, the nonlinear model predictive control algorithm is adapted to leverage the nonlinear dynamics model for trajectory tracking. Finally, the parafoil kinematic model is utilized to reduce the computational burden of trajectory calculation, and kinematic model is updated by the moving horizon correction algorithm to improve the trajectory accuracy. Simulation results demonstrate the effectiveness and computational efficiency of the proposed coordinated guidance and control method for the multiple parafoil landing.

Tarik Houichime, Younes EL Amrani

This paper introduces an innovative approach for the autonomous landing of Unmanned Aerial Vehicles (UAVs) using only a front-facing monocular camera, therefore obviating the requirement for depth estimation cameras. Drawing on the inherent human estimating process, the proposed method reframes the landing task as an optimization problem. The UAV employs variations in the visual characteristics of a specially designed lenticular circle on the landing pad, where the perceived color and form provide critical information for estimating both altitude and depth. Reinforcement learning algorithms are utilized to approximate the functions governing these estimations, enabling the UAV to ascertain ideal landing settings via training. This method's efficacy is assessed by simulations and experiments, showcasing its potential for robust and accurate autonomous landing without dependence on complex sensor setups. This research contributes to the advancement of cost-effective and efficient UAV landing solutions, paving the way for wider applicability across various fields.

Gonzalo G. de Diego, Georg Stadler

Complex physical systems which exhibit fluid-like behavior are often modeled as non-Newtonian fluids. A crucial element of a non-Newtonian model is the rheology, which relates inner stresses with strain-rates. We propose a framework for inferring rheological models from data that represents the fluid's effective viscosity with a neural network. By writing the rheological law in terms of tensor invariants and tailoring the network's properties, the inferred model satisfies key physical and mathematical properties, such as isotropic frame-indifference and existence of a convex potential of dissipation. Within this framework, we propose two approaches to learning a fluid's rheology: 1) a standard regression that fits the rheological model to stress data and 2) a PDE-constrained optimization method that infers rheological models from velocity data. For the latter approach, we combine finite element and machine learning libraries. We demonstrate the accuracy and robustness of our method on land and sea ice rheologies which also depend on external parameters. For land ice, we infer the temperature-dependent Glen's law and, for sea ice, the concentration-dependent shear component of the viscous-plastic model. For these two models, we explore the effects of large data errors. Finally, we infer an unknown concentration-dependent model that reproduces Lagrangian ice floe simulation data. Our method discovers a rheology that generalizes well outside of the training dataset and exhibits both shear-thickening and thinning behaviors depending on the concentrations.

E. Garnier, S. Lavorel, P. Ansquer et al.

Federica Bianchi, Rossella Moscarelli

The conquest of new public spaces is one of the main options in processes of urban regeneration. It seems essential in contemporary cities, since our life occurs more and more indoors and in private contexts, reducing the role of public and outdoor activities. Among cultural-based urban regeneration projects that operate within those spaces waiting for an improvement of the existing public functions, schools can play a particularly prominent role, as well spread and symbolic institutions with an educational mission for young people. From this perspective, the paper discusses how school squares, namely the urban areas close to the entrance of schools, can be designed and regenerated to produce a real public space where the city meets the school and vice versa. The paper presents a methodology to classify different typologies of school squares, based on an extensive analysis on over 600 school squares, located in the provinces of Milan, Turin and Varese. On the basis of such classification, some guidelines are discussed in order to propose a strategy to redesign these symbolic spaces and to conquer them as public areas.

Alberto Acosta

Atrás quedan las promesas del “desarrollo”, nutridas de uno de los corazones de la Modernidad: el “progreso”. En la vorágine, estamos abocados a replantearnos el tema del trabajo y del ocio. Se ha transformado el fenómeno del “ocio”, para expresar libertad y autonomía en un espacio mercantil de la vida misma. El “ocio mercantil” es reflejo de un mundo “mal desarrollado”, donde “trabajo” y “ocio” terminan igualmente alienados a la acumulación del capital. Pero no todo es desalentador. Hay reflexiones y acciones que demandan la construcción de sociedades radicalmente distintas. Palabras clave: Modernidad, Desarrollo, Progreso, Ocio y Trabajo.

Eloy Peña-Asensio, Álvaro-Steve Neira-Acosta, Juan Miguel Sánchez-Lozano

The selection of a landing site within the Artemis Exploration Zone (AEZ) involves multiple factors and presents a complex problem. This study evaluates potential landing sites for the Artemis III mission using a combination of Geographic Information Systems (GIS) and Multi-Criteria Decision Making (MCDM) methodologies, specifically the TOPSIS algorithm. By integrating topographic, illumination, and mineralogy data of the Moon, we assess 1247 locations that meet the Human Landing System (HLS) requirements within 13 candidate regions and Site 004 near the lunar south pole. Criteria considered include surface visibility, HLS-astronaut line of sight, Permanently Shadowed Regions (PSRs), sunlight exposure, direct communication with Earth, geological units, and mafic mineral abundance. Site DM2 (Nobile Rim 2), particularly the point at latitude 84°12'5.61" S (-84.20156°) and longitude 60°41'59.61" E (60.69989°), is the optimal location for landing. Sensitivity analysis confirms the robustness of our approach, validating the suitability of the best location despite the MCDM method employed and variations in criteria weightings to prioritize illumination and PSRs. This research demonstrates the applicability of GIS-MCDM techniques for lunar exploration and the potential benefits they can bring to the Artemis program.

L. Miles, V. Kapos

Yu Miao, Alexandre Yokochi, Goran Jovanovic et al.

Non-thermal plasma as a tool in chemical reaction engineering has been studied for many years. The temperature of electrons in non-thermal plasma far exceeds other particles, which leads to its high efficiency. Besides the well-studied destruction of volatile organic compounds (VOCs), the reaction environment generated by non-thermal plasma is also suitable for the activation of many significant gas-phase chemical reactions, e.g., as methane coupling, reduction of carbon dioxide, ammonia synthesis, nitrogen fixation, as well as some liquid phase chemical reactions such as the treatment of contaminated water. Material synthesis is another target field of non-thermal plasma. Plasma in micro scale with several enhanced properties makes it an even more promising tool for plasma-chemical processing. This work summarizes different types of non-thermal plasmas and their performance in commonly studied chemical reactions. The advantages gained by generating non-thermal plasma in micro scale with constricted spaces, reduced timescales, and micro-/nano-structured electrodes are also discussed.

Ali Heydarnezhad, Seyed Mohammadbagher Jafari, Jafar Rahmani et al.

The Asian Productivity Organization (APO) reports a one percent increase in Iran's Total Factor Productivity (TFP) index when compared to the majority of Asian countries and some reference countries in the long-term horizon of 50 years. In fact, the growth of labor productivity between 2010 and 2019 was less than all Asian countries. The present study was conducted with the aim of presenting a productivity pattern based on social capital.  Using the meta-synthesis approach and MaxQDA software, and after selecting 79 studies from among 580 previous studies, the dimensions, components and indicators of the model were extracted and identified. Based on the research findings, 9 dimensions, 24 main categories and 163 sub-categories (code)were identified. The nine dimensions are trust building, communication management, learning and growth, cultural factors, facilitator strategies, organizational factors, human resources, achieving sustainable development and profitability. The results of the emphasis of the previous research on each of the main categories using Shannon entropy technique and Excel software showed that growth and maturity and economic programs are the most important and the least important categories among the 24 categories, respectively. It is suggested that all managers update the human capital management process in accordance with the social capital based productivity pattern by hiring expert consultants and creating a special office for productivity management. Then, while periodically evaluating productivity based on the proposed pattern, all payments, bonuses and promotions of employees and managers should be base on the amount of their effort and participation in order to increase social capital and productivity.