Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: SFA

Sortuj według:

Ogranicz wyniki do:

An SFA-HMM performance evaluation method using state difference optimization for running gear systems in high-speed trains

Cheng Chao, Wang Meng, Wang Jiuhe, Shao Junjie, Chen Hongtian

International Journal of Applied Mathematics and Computer Science

2022

Vol. 32, no. 3

389--402

The evaluation of system performance plays an increasingly important role in the reliability analysis of cyber-physical systems. Factors of external instability affect the evaluation results in complex systems. Taking the running gear in high-speed trains as an example, its complex operating environment is the most critical factor affecting the performance evaluation design. In order to optimize the evaluation while improving accuracy, this paper develops a performance evaluation method based on slow feature analysis and a hidden Markov model (SFA-HMM). The utilization of SFA can screen out the slowest features as HMM inputs, based on which a new HMM is established for performance evaluation of running gear systems. In addition to directly classical performance evaluation for running gear systems of high-speed trains, the slow feature statistic is proposed to detect the difference in the system state through test data, and then eliminate the error evaluation of the HMM in the stable state. In addition, indicator planning and status classification of the data are performed through historical information and expert knowledge. Finally, a case study of the running gear system in high-speed trains is discussed. After comparison, the result shows that the proposed method can enhance evaluation performance.

Semifluorowane alkany (SFA) - właściwości w ciele stałym, roztworach i na granicach międzyfazowych

Broniatowski M., Dynarowicz-Łątka P.

Wiadomości Chemiczne

2004

[Z] 58, 7-8

535-569

Semifluorinated n-alkanes (SFA), of the general formula F(CF2)m-(CH2)nH (abbreviated as FmHn) consist of a linear hydrocarbon segment linked to a fluorocarbon chain. These two units are highly incompatible, what arises from a very different physical and mechanical properties of hydrogenated and perfluorinated hydrocarbons. The presence of two opposing segments within one molecule makes semifluorinated alkanes a very interesting class of compounds, which show a particular behavior in bulk and at interfaces. Their highly asymmetric structure, arising from the incompatibility of the both constituent parts, results in surface activity of these molecules (so-called primitive surfactants) when dissolved in organic solvents, and allows for the Langmuir monolayer formation if spread at the air/water interface, despite of the absence of polar group. Since 1984, semifluorinated alkanes have been subject to many studies concerning their structure and physicochemical properties in bulk phase (solid and liquid) and at interfaces (oil/water; air/water). The present article reviews the results obtained so far.