scholarly journals Validation of a Long-Range Trajectory Model Using Gas Balloon Tracks from the Gordon Bennett Cup 95

1997 ◽  
Vol 36 (6) ◽  
pp. 711-720 ◽  
Author(s):  
Kathrin Baumann ◽  
Andreas Stohl
Keyword(s):  
Long Range ◽  
Computation Time ◽  
Wind Fields ◽  
Time Step ◽  
Long Distance ◽  
Trajectory Model ◽  
Trajectory Calculations ◽  
Stochastic Errors ◽  
Divergent Wind

Abstract In September 1995, 18 gas balloon teams competed at the Gordon Bennett Cup, a long-distance ballooning event. The landing positions, travel times of all teams, and detailed information on the tracks of four teams are available. A special version of the trajectory model FLEXTRA (flexible trajectories) is used that allows the heights of calculated trajectories to be adjusted to the respective balloon heights at every computation time step. The comparison of calculated and observed balloon trajectories allows a validation of the trajectory model. In this case study, the agreement between calculated and balloon trajectories was good, with average relative transport errors of less than 20% of the travel distance after 46 h of travel time. Most of the trajectory errors originate from interpolation errors and from amplifications of small position disturbances in divergent wind fields. Trajectory ensembles, taking into account stochastic errors occurring during the trajectory calculations, are shown to be very reliable in assessing the uncertainties of the computed trajectories. In the present study, the balloon tracks were enveloped by the ensemble trajectories most of the time, suggesting that errors in the analyzed wind fields were relatively small.

Eulerian and Lagrangian perspectives on a Foehn event in the Alpine region

2020 ◽  
Author(s):  
Lukas Jansing ◽  
Michael Sprenger
Keyword(s):  
Cross Sections ◽  
Synoptic Situation ◽  
Wind Fields ◽  
Mountain Meteorology ◽  
Time Step ◽  
Po Valley ◽  
Long Duration ◽  
First Results ◽  
Diabatic Processes

<p>Foehn-related research has a long-standing tradition in mountain meteorology. In this context, the reason for Foehn air warming and the factors determining the descent of the air into the valleys have gained particular interest. Here, we readdress those research questions by combining a COSMO model hindcast at 1 km horizontal and 10 min temporal resolution with air parcel trajectories for a South Foehn case study in November 2016. The sub-synoptic situation in the model is studied using horizonal cross sections at different levels. Vertical cross sections in the Po valley and along the axes of major Foehn valleys complement the Eulerian analysis.</p><p>The selected event is characterized by its long duration, a far northern extent and exceptionally strong gusts. A low-level jet is discernible west of the Alps and a pronounced north-south pressure gradient develops. A striking feature is the strong tilt of the isentropes downstream of the Alpine crest. Trajectories reveal the versatile pathways of air parcels over major Alpine passes before they descend into the Foehn valleys. Differences with respect to upstream ascent and descent are observed for the different valleys. By tracing meteorological variables along the trajectories, the relative importance of adiabatic and diabatic processes for the Foehn air warming is quantified. The properties of air parcels that descend into the valleys or stay at higher levels are contrasted in order to identify factors that determine the descent.</p><p>The case study will set the scene for a forthcoming detailed analysis of Foehn flows based on online trajectories that make use of the wind fields at every model time step. The analysis will be extended to a number of cases representing the different South Foehn varieties. We will trace the temperature tendencies due to all diabatic processes (cloud processes, radiation, turbulence) along the trajectories in order to quantify their respective importance for Foehn air warming. First results in this extended framework will be presented.</p>

scholarly journals Modulating long-range energetics via helix stabilization: a case study using T4 lysozyme

2018 ◽  
Author(s):  
Sabriya N. Rosemond ◽  
Kambiz M. Hamadani ◽  
Jamie H.D. Cate ◽  
Susan Marqusee
Keyword(s):  
Protein Folding ◽  
Long Range ◽  
Salt Bridge ◽  
Globular Protein ◽  
Full Length ◽  
T4 Lysozyme ◽  
Long Distance ◽  
Terminal Fragment ◽  
The Stability

Cooperative protein folding requires distant regions of a protein to interact and provide mutual stabilization. The mechanism of this long-distance coupling remains poorly understood. Here, we use T4 lysozyme (T4L*) as a model to investigate long-range communications across a globular protein. T4L* is composed of two structurally distinct subdomains, although it behaves in a two-state manner at equilibrium. The subdomains of T4L* are connected via two topological connections: the N-terminal helix that is structurally part of the C-terminal subdomain (the A-helix) and a long helix that spans both subdomains (the C-helix). To understand the role that the C-helix plays in cooperative folding, we analyzed a circularly permuted version of T4L* (CP13*), whose subdomains are connected only by the C-helix. We demonstrate that when isolated as individual fragments, both subdomains of CP13* can fold autonomously into marginally stable conformations. The energetics of the N-terminal subdomain depend on the formation of a salt bridge known to be important for stability in the full-length protein. We show that the energetic contribution of the salt bridge to the stability of the N-terminal fragment increases when the C-helix is stabilized, such as occurs upon folding of the C-terminal subdomain. These results suggest a model where long-range energetic coupling is mediated by helix stabilization.

COMBINING ORAL TRADITIONS AND BAYESIAN CHRONOLOGICAL MODELING TO UNDERSTAND VILLAGE DEVELOPMENT IN THE GULF OF PAPUA (PAPUA NEW GUINEA)

Radiocarbon ◽  
2021 ◽  
pp. 1-21
Author(s):  
Chris Urwin ◽  
Quan Hua ◽  
Henry Arifeae
Keyword(s):  
Papua New Guinea ◽  
New Guinea ◽  
Oral Traditions ◽  
Long Distance ◽  
Spatial History ◽  
The Past ◽  
History Of ◽  
Gulf Of Papua ◽  
The Village

ABSTRACT When European colonists arrived in the late 19th century, large villages dotted the coastline of the Gulf of Papua (southern Papua New Guinea). These central places sustained long-distance exchange and decade-spanning ceremonial cycles. Besides ethnohistoric records, little is known of the villages’ antiquity, spatiality, or development. Here we combine oral traditional and 14C chronological evidence to investigate the spatial history of two ancestral village sites in Orokolo Bay: Popo and Mirimua Mapoe. A Bayesian model composed of 35 14C assays from seven excavations, alongside the oral traditional accounts, demonstrates that people lived at Popo from 765–575 cal BP until 220–40 cal BP, at which time they moved southwards to Mirimua Mapoe. The village of Popo spanned ca. 34 ha and was composed of various estates, each occupied by a different tribe. Through time, the inhabitants of Popo transformed (e.g., expanded, contracted, and shifted) the village to manage social and ceremonial priorities, long-distance exchange opportunities and changing marine environments. Ours is a crucial case study of how oral traditional ways of understanding the past interrelate with the information generated by Bayesian 14C analyses. We conclude by reflecting on the limitations, strengths, and uncertainties inherent to these forms of chronological knowledge.

scholarly journals A Long-Distance Communication Architecture for Medical Devices Based on LoRaWAN Protocol

Electronics ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 940
Author(s):  
Nicoleta Cristina Gaitan
Keyword(s):  
Energy Consumption ◽  
Long Range ◽  
Medical Devices ◽  
Low Energy ◽  
Area Network ◽  
Wide Area Network ◽  
Long Distance ◽  
Communication Architecture ◽  
Low Energy Consumption ◽  
Distance Communication

Recent market studies show that the market for remote monitoring devices of different medical parameters will grow exponentially. Globally, more than 4 million individuals will be monitored remotely from the perspective of different health parameters by 2023. Of particular importance is the way of remote transmission of the information acquired from the medical sensors. At this time, there are several methods such as Bluetooth, WI-FI, or other wireless communication interfaces. Recently, the communication based on LoRa (Long Range) technology has had an explosive development that allows the transmission of information over long distances with low energy consumption. The implementation of the IoT (Internet of Things) applications using LoRa devices based on open Long Range Wide-Area Network (LoRaWAN) protocol for long distances with low energy consumption can also be used in the medical field. Therefore, in this paper, we proposed and developed a long-distance communication architecture for medical devices based on the LoRaWAN protocol that allows data communications over a distance of more than 10 km.

scholarly journals A new boundary element algorithm for modeling and simulation of nonlinear thermal stresses in micropolar FGA composites with temperature-dependent properties

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Mohamed Abdelsabour Fahmy
Keyword(s):  
Modeling And Simulation ◽  
Boundary Element ◽  
Thermal Stresses ◽  
Computation Time ◽  
Functionally Graded ◽  
Temperature Dependent ◽  
Time Step ◽  
Kirchhoff Transformation ◽  
Nonlinear Temperature ◽  
Temperature Dependent Properties

AbstractThe main aim of this article is to develop a new boundary element method (BEM) algorithm to model and simulate the nonlinear thermal stresses problems in micropolar functionally graded anisotropic (FGA) composites with temperature-dependent properties. Some inside points are chosen to treat the nonlinear terms and domain integrals. An integral formulation which is based on the use of Kirchhoff transformation is firstly used to simplify the transient heat conduction governing equation. Then, the residual nonlinear terms are carried out within the current formulation. The domain integrals can be effectively treated by applying the Cartesian transformation method (CTM). In the proposed BEM technique, the nonlinear temperature is computed on the boundary and some inside domain integral. Then, nonlinear displacement can be calculated at each time step. With the calculated temperature and displacement distributions, we can obtain the values of nonlinear thermal stresses. The efficiency of our proposed methodology has been improved by using the communication-avoiding versions of the Arnoldi (CA-Arnoldi) preconditioner for solving the resulting linear systems arising from the BEM to reduce the iterations number and computation time. The numerical outcomes establish the influence of temperature-dependent properties on the nonlinear temperature distribution, and investigate the effect of the functionally graded parameter on the nonlinear displacements and thermal stresses, through the micropolar FGA composites with temperature-dependent properties. These numerical outcomes also confirm the validity, precision and effectiveness of the proposed modeling and simulation methodology.

Long distance pollen-mediated gene flow at a landscape level: the weed beet as a case study

2007 ◽  
Vol 16 (18) ◽  
pp. 3801-3813 ◽  
Author(s):  
STÉPHANE FÉNART ◽  
FRÉDÉRIC AUSTERLITZ ◽  
JOËL CUGUEN ◽  
JEAN-FRANÇOIS ARNAUD
Keyword(s):  
Gene Flow ◽  
Long Distance ◽  
Landscape Level

Time suboptimal control of industrial manipulators along specified paths while keeping an end-effector orientation unchanged

Robotica ◽  
2003 ◽  
Vol 21 (2) ◽  
pp. 153-161 ◽  
Author(s):  
S. Kilicaslan ◽  
Y. Ercan
Keyword(s):  
Suboptimal Control ◽  
Time Step ◽  
End Effector ◽  
Industrial Manipulator ◽  
Industrial Manipulators ◽  
Angular Velocities ◽  
System Equations ◽  
Six Degree Of Freedom ◽  
Time Suboptimal Control

A method for the time suboptimal control of an industrial manipulator that moves along a specified path while keeping its end-effector orientation unchanged is proposed. Nonlinear system equations that describe the manipulator motion are linearized at each time step along the path. A method which gives control inputs (joint angular velocities) for time suboptimal control of the manipulator is developed. In the formulation, joint angular velocity and acceleration limitations are also taken into consideration. A six degree of freedom elbow type manipulator is used in a case study to verify the method developed.

Determination of the Minimum Distance Between Moving Objects Including Velocity Information

1993 ◽  
Author(s):  
Meyer Nahon
Keyword(s):  
Minimum Distance ◽  
Moving Objects ◽  
Rapid Determination ◽  
Computation Time ◽  
Optimization Techniques ◽  
Real Time Control ◽  
Time Step ◽  
Time Control ◽  
Velocity Information

Abstract The rapid determination of the minimum distance between objects is of importance in collision avoidance for a robot maneuvering among obstacles. Currently, the fastest algorithms for the solution of this problem are based on the use of optimization techniques to minimize a distance function. Furthermore, to date this problem has been approached purely through the position kinematics of the two objects. However, although the minimum distance between two objects can be found quickly on state-of-the-art hardware, the modelling of realistic scenes entails the determination of the minimum distances between large numbers of pairs of objects, and the computation time to calculate the overall minimum distance between any two objects is significant, and introduces a delay which has serious repercussions on the real-time control of the robot. This paper presents a technique to modify the original optimization problem in order to include velocity information. In effect, the minimum distance calculation is performed at a future time step by projecting the effect of present velocity. This method has proven to give good results on a 6-dof robot maneuvering among obstacles, and has allowed a complete compensation of the lags incurred due to computational delays.

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