The assessment of the risks from an exposure to electromagnetic fields with frequency 50 Hz at places under transmission power lines includes the determination of the magnetic flux density. It may be ensured by measur...
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ISBN:
(纸本)9783319683249
The assessment of the risks from an exposure to electromagnetic fields with frequency 50 Hz at places under transmission power lines includes the determination of the magnetic flux density. It may be ensured by measurements or calculations. The paper presents a computing approach for determination of the magnetic flux density under overhead electrical power lines. By the help of a specialized computer program created by the authors, the data for the magnetic flux density at points at an arbitrary height from the ground, transversely from the center of the tower of the transmission lines of 220 kV and 400 kV, are presented. The calculation approach is based on the condition that the phase conductors are infinitely long and rectilinear, located close to a flat surface of a conductive medium (the ground). Then the total magnetic field can be considered as a superposition of the magnetic fields of the line conductors and their mirror images. So, the vector of the total magnetic flux density can be determined by a vector sum of the vectors of the magnetic flux densities of all the conductors. The presented results are extracted for different constructions of electrical power line towers and horizontal arrangements of the phase conductors. The results describe the field characteristics around some typical constructions of transmission power lines of 220 kV and 400 kV.
The problem of estimating attitude for actively maneuvering or passively rotating space objects with unknown mass properties/external torques and uncertain shape models is addressed. To account for agile space object ...
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The problem of estimating attitude for actively maneuvering or passively rotating space objects with unknown mass properties/external torques and uncertain shape models is addressed. To account for agile space object maneuvers, angular rates are simply assumed to be random inputs (e. g., process noise), and model uncertainty is accounted for in a bias state with dynamics derived using first principles. Bayesian estimation approaches are used to estimate the resulting severely non-Gaussian and multimodal state distributions. Simulated results are given, conclusions regarding performance are made, and future work is outlined.
Many modern engineering problems are inherently multidisciplinary, requiring input from a variety of subject matter experts. Each discipline may impose its own computational requirements, potentially conflicting with ...
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ISBN:
(数字)9781624107115
ISBN:
(纸本)9781624107115
Many modern engineering problems are inherently multidisciplinary, requiring input from a variety of subject matter experts. Each discipline may impose its own computational requirements, potentially conflicting with other disciplines. Compounding this, in many fields, experts use specific software that may not interface easily with other disciplines. Therefore, combining multiple fields into multidisciplinary design optimization (MDO) may entail significant work on analysis tool interfaces. This paper proposes a standard data and communication interface for MDO applications. Requirements for such a standard are discussed before reviewing relevant technologies. The data conventions and communication protocol for the proposed standard, Philote, are detailed for both explicit and implicit disciplines. Numerical studies were conducted to benchmark performance and quantify latency as well as to demonstrate Philote's ability to operate over large geographical distances. Finally, the wider ramifications of the proposed standard are discussed with a particular focus on heterogeneous and cloud-native computing.
We propose a new method to identify similar thunderstorm spatial-temporal sequences to support airline operations based on the optimal transport theory. Different from existing geometric methods, which often suffer fr...
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ISBN:
(数字)9781624107115
ISBN:
(纸本)9781624107115
We propose a new method to identify similar thunderstorm spatial-temporal sequences to support airline operations based on the optimal transport theory. Different from existing geometric methods, which often suffer from over-approximation of the covering geometric objects, our method models each thunderstorm as a probability distribution supported by the observed weather data. The core of our approach lies in measuring the similarity between thunderstorm sequences through the Wasserstein distance of their respective probability distributions. By setting different time weights and filter functions, this method can also incorporate the temporal features of the thunderstorms and consider the weather impact on key airspace/airport infrastructures. Furthermore, we apply a clustering algorithm within the probability distribution space of thunderstorms to categorize common patterns of archived thunderstorms in a given airspace region. We illustrate the effectiveness of this new method with our results with real-world weather data in the Dallas Fort Worth airspace.
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