Development of General-Purpose Root-Finding Module for General Mission Analysis Tool

2019 ◽  
Vol 20 (1) ◽  
pp. 315-324
Author(s):  
Minhee Kim ◽  
Sang-Young Park ◽  
Steven P. Hughes
2015 ◽  
Vol 50 (4) ◽  
pp. 157-168 ◽  
Author(s):  
Mohammed Chessab Mahdi

Abstract Orbit design for KufaSat Nano-satellites is presented. Polar orbit is selected for the KufaSat mission. The orbit was designed with an Inclination which enables the satellite to see every part of the earth. KufaSat has a payload for imaging purposes which require a large amount of power, so the orbit is determined to be sun synchronous in order to provide the power through solar panels. The KufaSat mission is designed for the low earth orbit. The six initial Keplerian Elements of KufaSat are calculated. The orbit design of KufaSat according to the calculated Keplerian elements has been simulated and analyzed by using MATLAB first and then by using General Mission Analysis Tool.


2018 ◽  
Vol 1 (1) ◽  
pp. 7-30 ◽  
Author(s):  
Nigel Paul Bannister

Astrodynamics is the study of the motion of artificial satellites and spacecraft, subject to both natural and artificially induced forces. It combines celestial mechanics, attitude dynamics and aspects of positional astronomy to describe spacecraft motion and enable the planning and analysis of missions. It is of significant interdisciplinary interest with relevance to physics, astronomy and spaceflight engineering, but can be challenging to deliver in an effective, engaging manner because of the often abstract nature of some concepts, the four-dimensional nature of the problems, and the computation required to explore realistic astrodynamics behaviour. The University of Leicester has adopted NASA’s General Mission Analysis Tool as a core resource to support active learning in this subject for students at Level 6 (BSc) and Level 7 (MSc). This paper describes our approach to the implementation of GMAT as an essential element of teaching and learning in the subject.


Author(s):  
M. S. Anand ◽  
R. Eggels ◽  
M. Staufer ◽  
M. Zedda ◽  
J. Zhu

A general-purpose combustion Computational Fluid Dynamics (CFD) design analysis tool has been developed. The method is pressure-based and applicable to both incompressible and compressible flows. The unstructured finite-volume approach used can take arbitrary shapes of mesh cells to resolve complicated geometries. Turbulence is simulated either by Reynolds-Averaged Navier-Stokes (RANS) or by Large Eddy Simulation (LES) approaches. Combustion is modeled by various combinations of combustion chemistry and combustion-turbulence models including transport probability density function (PDF) model. A Lagrangian approach is used to simulate fuel spray droplet. The resulting tool has being used in routine combustor simulations for a variety of commercial and military combustor development programs. Application examples presented include simulations of several combustors and comparisons with available rig data.


2019 ◽  
Author(s):  
Hao Chen ◽  
Shizhe Chen ◽  
Xinyi Deng

SummaryNeuropixels probes present exciting new opportunities for neuroscience, but such large-scale high-density recordings also introduce unprecedented challenges in data analysis. Neuropixels data usually consist of hundreds or thousands of long stretches of sequential spiking activities that evolve non-stationarily over time and are often governed by complex, unknown dynamics. Extracting meaningful information from the Neuropixels recordings is a non-trial task. Here we introduce a general-purpose, graph-based statistical framework that, without imposing any parametric assumptions, detects points in time at which population spiking activity exhibits simultaneous changes as well as changes that only occur in a subset of the neural population, referred to as “change-points”. The sequence of change-point events can be interpreted as a footprint of neural population activities, which allows us to relate behavior to simultaneously recorded high-dimensional neural activities across multiple brain regions. We demonstrate the effectiveness of our method with an analysis of Neuropixels recordings during spontaneous behavior of an awake mouse in darkness. We observe that change-point dynamics in some brain regions display biologically interesting patterns that hint at functional pathways, as well as temporally-precise coordination with behavioral dynamics. We hypothesize that neural activities underlying spontaneous behavior, though distributed brainwide, show evidences for network modularity. Moreover, we envision the proposed framework to be a useful off-the-shelf analysis tool to the neuroscience community as new electrophysiological recording techniques continue to drive an explosive proliferation in the number and size of data sets.


Author(s):  
Bryce A. Roth ◽  
Erin M. McClure ◽  
Travis W. Danner

This paper describes the implementation and application of a new set of thermodynamic loss analysis tools in the Numerical Propulsion System Simulation. This analysis tool set is intended to enable fast, accurate estimation of losses in an engine cycle model with minimal effort on the part of the user. The basic thermodynamic concepts and analysis methods are first described. Next, the implementation of the necessary thermodynamic calculation functions is described. These functions are intended to be used in conjunction with a general-purpose loss analysis element to facilitate estimation of all losses in an engine cycle model. The loss analysis element is described in detail and is subsequently used to analyze a mixed flow turbofan engine. Typical performance and loss results are presented. The resultant detailed loss information is not normally available when using standard cycle analysis methods. The information gained from this analysis is useful in that it yields insight into the underlying losses that contribute to the overall engine performance.


2021 ◽  
Vol 46 (3) ◽  
pp. 42-46
Author(s):  
Yang Zhou ◽  
Cyrille Artho

Java Path nder (JPF) is a very versatile program analysis tool, but understanding the error traces it generates is challenging. Visualizing traces can facilitate their understanding. Earlier attempts to visualize traces have resulted in specialized tools that do not interoperate with other frameworks. We present TC4JPF, which builds on Eclipse Trace Compass and enables Trace Compass to visualize JPF traces. With TC4JPF, we leverage the scalability and capabilities of Trace Compass and provide the rst solution that visualizes JPF traces in a general-purpose trace visualization tool.


Author(s):  
James D. Lynch ◽  
Martin J. Vanderploeg

Abstract Simulation of three dimensional multibody systems is a sophisticated analysis tool that is often used for design. Before a prototype is constructed, simulation provides a designer with a model that can be modified until a desired result is achieved. General purpose multibody dynamics packages are currently used around the world. During the evolution of multibody simulation, three dimensional graphics became an important tool for both system definition and evaluation of simulation results. In fact, three dimensional graphics was an enabling technology for simulation of large, complex three dimensional systems. However, the process has remained essentially a batch operation in which the analysis of the results is not accessible until the solution is complete. Changes in the model require starting the process over. Although the use of computer simulation in the place of early prototypes was a significant step forward in terms of reduced time and cost to develop a design, even more improvement is possible when the user is able to interactively change and analyze the system at any time in lieu of having to go through discrete trial and error steps. In order to reach this next level, this paper introduces an interactive computer graphics interface for three dimensional multibody dynamic simulation.


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