A phase‐space technique for the perturbation expansion of Schrödinger propagators

1995 ◽  
Vol 36 (1) ◽  
pp. 30-61 ◽  
Author(s):  
A. O. Barvinsky ◽  
T. A. Osborn ◽  
Yu. V. Gusev
Keyword(s):  
Phase Space ◽  
Perturbation Expansion ◽  
Space Technique

scholarly journals Determining the Extratropical Transition Onset and Completion Times of Typhoons Mindulle (2004) and Yagi (2006) Using Four Methods

2012 ◽  
Vol 27 (6) ◽  
pp. 1394-1412 ◽  
Author(s):  
Qian Wang ◽  
Qingqing Li ◽  
Gang Fu
Keyword(s):  
Phase Space ◽  
Potential Vorticity ◽  
Onset Time ◽  
Data Sources ◽  
Extratropical Transition ◽  
Forecast Uncertainty ◽  
Factors Associated ◽  
Space Technique ◽  
Isentropic Potential Vorticity ◽  
Completion Times

Abstract Four methods for determining the extratropical transition (ET) onset and completion times of Typhoons Mindulle (2004) and Yagi (2006) were compared using four numerically analyzed datasets. The open-wave and scalar frontogenesis parameter methods failed to smoothly and consistently determine the ET completion from the four data sources, because some dependent factors associated with these two methods significantly impacted the results. Although the cyclone phase space technique succeeded in determining the ET onset and completion times, the ET onset and completion times of Yagi identified by this method exhibited a large distinction across the datasets, agreeing with prior studies. The isentropic potential vorticity method was also able to identify the ET onset times of both Mindulle and Yagi using all the datasets, whereas the ET onset time of Yagi determined by such a method differed markedly from that by the cyclone phase space technique, which may create forecast uncertainty.

scholarly journals A Similarity Comparison Method of Homologous Fault Response Fragments under Variable Rotational Speed

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Zhiyang He ◽  
Weidong Cheng ◽  
Weigang Wen
Keyword(s):  
Phase Space ◽  
Health Management ◽  
Fault Detection And Diagnosis ◽  
Phase Portraits ◽  
Similarity Measurement ◽  
Variable Speed ◽  
Space Trajectories ◽  
Space Technique ◽  
Improve Measurement ◽  
Phase Space Trajectories

Effective fault detection and diagnosis (FDD) for rotating machinery is always a focus issue in improving the prognostic and health management (PHM) of the equipments. The existing usage of similarity measurement has been widely spread in searching the homologous fault responses from vibration signals, but most of them are just suitable for stable speed and cannot be applied in all variable speed conditions. In order to improve measurement performance, a fast-meshed phase portrait (FMPP) frame combining the phase-space technique and box-scoring calculation is proposed. Firstly, the variable-speed signal is divided into multiple undetermined fragments according to fault characteristic orders (FCOs). Secondly, the undetermined fragments are reconstructed into corresponding phase-space trajectories to overcome the time-delay matching inconsistency of the variable speed fragments. Thirdly, the phase-space trajectories are mapped into meshed phase portraits via box-scoring calculation. Such decisive calculation can effectively transforms the diverse unequal fragments into the phase diagrams with same size, which saves time for the subsequent similarity measurement. Finally, the proposed FMPP is tested both for accuracy and timeliness on a self-built bearing bench, where the order tracking (OT) and dynamic time warping (DTW) methods are used for the comparisons. The experiments proved the effectiveness of the proposed method.

A one-dimensional self-gravitating stellar gas

1966 ◽  
Vol 25 ◽  
pp. 46-48 ◽  
Author(s):  
M. Lecar
Keyword(s):  
Gravitational Field ◽  
Phase Space ◽  
Motion Picture ◽  
Space Distribution ◽  
Two Dimensional ◽  
One Dimensional ◽  
Phase Space Distribution ◽  
Dimensional Phase Space ◽  
The Mean

“Dynamical mixing”, i.e. relaxation of a stellar phase space distribution through interaction with the mean gravitational field, is numerically investigated for a one-dimensional self-gravitating stellar gas. Qualitative results are presented in the form of a motion picture of the flow of phase points (representing homogeneous slabs of stars) in two-dimensional phase space.

Phase space of mechanical systems with a gauge group

1991 ◽  
Vol 161 (2) ◽  
pp. 13-75 ◽  
Author(s):  
Lev V. Prokhorov ◽  
Sergei V. Shabanov
Keyword(s):  
Phase Space ◽  
Gauge Group ◽  
Mechanical Systems
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