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Satellites
Published in Mohammad Razani, Commercial Space Technologies and Applications, 2018
The primary task in the satellite mission analysis is to select the optimum orbit that best enables the satellite and payload to perform their missions. Providing the mission is feasible, trade-offs are performed in order to find a suitable orbit that meets the mission goals. To calculate the approximate orbits for artificial satellites, Kepler’s Laws are used. These laws describe the motion of any two bodies around each other. In all cases, both bodies orbit around the common center of mass, the barycenter, with neither one having their center of mass exactly at one focus of an ellipse. However, both orbits are ellipses with one focus at the barycenter. Satellites that orbit the Earth also follow Kepler’s laws that apply to the motion of the planets around the Sun.
Satellites
Published in Mohammad Razani, Information, Communication, and Space Technology, 2017
The primary task in the satellite mission analysis is to select the optimum orbit that best enables the satellite and payload to perform their missions. Providing the mission is feasible, trade-offs are performed in order to find a suitable orbit that meets the mission goals. To calculate the approximate orbits for artificial satellites, Kepler’s Laws are used. These laws describe the motion of any two bodies around each other. In all cases, both bodies orbit around the common center of mass, the barycenter, with neither one having their center of mass exactly at one focus of an ellipse. However, both orbits are ellipses with one focus at the barycenter. Satellites that orbit the Earth also follow Kepler’s laws that apply to the motion of the planets around the Sun.
Maintaining Orbits
Published in Thomas Hockey, Jennifer Lynn Bartlett, Daniel C. Boice, Solar System, 2021
Thomas Hockey, Jennifer Lynn Bartlett, Daniel C. Boice
A complication of the real Universe is this: We talk about a planet ‘orbiting the Sun,’ but the Sun orbits the planet, too. Just as the planet moves under the grasp of the Sun's gravity, the Sun also is required to move under the influence of the planets. The planet performs most of the work in its dance with the Sun. The Sun wobbles almost imperceptibly as the planet whirls around it. Both move around a point between them known as their common center of mass, or barycenter.
Clustering Techniques Selection for a Hybrid Regression Model: A Case Study Based on a Solar Thermal System
Published in Cybernetics and Systems, 2023
María Teresa García-Ordás, Héctor Alaiz-Moretón, José-Luis Casteleiro-Roca, Esteban Jove, José Alberto Benítez-Andrades, Isaías García-Rodríguez, Héctor Quintián, José Luis Calvo-Rolle
The Davies-Bouldin index is a score used for the evaluation of clustering algorithms. It uses characteristics and quantities that are inherent to the data set, and is defined as the mean value of the samples Mk (among all the clusters), as is represented in Eq. (8). where represents the mean value distance from the points belonging to the cluster to their barycenter while is the distance between barycenters and (Eq. 10).
Navigation system with SLAM-based trajectory topological map and reinforcement learning-based local planner
Published in Advanced Robotics, 2021
Wuyang Xue, Peilin Liu, Ruihang Miao, Zheng Gong, Fei Wen, Rendong Ying
Second, nodes of topological map are generated with trajectory points. An octree of trajectory points is built. We represent each leaf of the octree with barycenter of each leaf. If the distance between two barycenters is less than a threshold , one barycenter will be removed. Remaining barycenters are nodes of our topological map. Compared with geometric center, barycenter is less likely to fall in dangerous area. An example is illustrated in Figure 5. If we limit the maximum number of trajectory points in a leaf to one, then barycenter of each leaf is just trajectory point itself. As all trajectory points are in safe area, all barycenters are definitely safe, too. As the number of trajectory points in a leaf increases, barycenters are more and more probable to fall in dangerous area. By tuning the maximum number of trajectory points in a leaf, the number of barycenters in dangerous area can be limited.
Curvature: An Indicator of the Mechanical Condition of Old Prestressed Concrete Bridges
Published in Structural Engineering International, 2018
Bernard Tonnoir, Christophe Carde, David Banant
Test Method LPC no. 82 distinguishes between two types of experimentation using curvature measurement, depending on the desired result1: Measurements are taken during one or more load tests in order to check the bending behavior of critical sections up to the maximum load. The “decompression moment method”2 used on hyperstatic bridges is a good example of this application. The complete system is generally comprised of several curvature frames which are simply placed either inside a box or directly on the pavement of the bridge, and which can—without inconvenience (but not without precaution)—stay close to or even straddled by the vehicles used during the tests. If necessary, the curvature frames can be moved in order to test other sections for various load cases.Long-term monitoring, including: Specific monitoring of an area with identified damage, or that has already been repaired, in order to detect any unfavorable changes.Indirect monitoring of prestressed forces by means of the lever arm of the tendons center of mass (barycenter). In the present study, this method was used to measure the changes in curvature over time on a bridge near Chamonix, France.