125,912 Hits in 4.5 sec

Data envelopment analysis of systems with multiple modes of functioning

S. Lozano, G. Villa
2017 Annals of Operations Research  
Many systems can operate in different modes of functioning.  ...  Conventional Data Envelopment Analysis (DEA) would ignore that fact and consider instead that the system is a black box, paying attention just to the overall input consumption and output production.  ...  It deals with the case in which the DMUs have multiple modes of functioning and operate a certain fraction of the time in each of these modes.  ... 
doi:10.1007/s10479-017-2733-7 fatcat:ilddzbrdobgcpjbyh23zb5exaa

Progress in Operational Analysis of Launch Vehicles in Nonstationary Flight [chapter]

George James, Mo Kaouk, Tim Cao
2013 Special Topics in Structural Dynamics, Volume 6  
This work reported herein uses a correlation-based two step operational modal analysis approach to process the relevant data sets for understanding and development of processes.  ...  The primary source of difficulty is due to the nonstationary nature of the situation. The system is changing, the environment is not steady, and there is an active control system operating.  ...  These include multiple modes, data stationarity, multiple sensors, numerical round-off error, system noise, the role that the phase of the analytic function may play, digital parameter shifting (as seen  ... 
doi:10.1007/978-1-4614-6546-1_6 fatcat:5u5gvosxmvgqbjuysu4vjkaiwi

Probabilistic Safety Assessment for UAS Separation Assurance and Collision Avoidance Systems

Asma Tabassum, Roberto Sabatini, Alessandro Gardi
2019 Aerospace (Basel)  
collision of unmanned aircraft systems (UAS) with other flight vehicles.  ...  with faults in system components.  ...  Conflicts of Interest: The authors declare no conflict of interest.  ... 
doi:10.3390/aerospace6020019 fatcat:houffjohz5hdtdvl7lxth2tlla

Ambient PMU Data Based System Oscillation Analysis Using Multivariate Empirical Mode Decomposition [article]

Shutang You
2021 arXiv   pre-print
Wide-area synchrophasor ambient measurements provide a valuable data source for real-time oscillation mode monitoring and analysis.  ...  that exists in multiple synchrophasor measurements at low amplitudes.  ...  There are two main categories of methods for oscillation analysis based on ambient and event data: transfer function based methods and subspace methods.  ... 
arXiv:2101.05203v2 fatcat:oxcr4xcknnh4noq63blcukxpeq

On Holo-Hilbert spectral analysis: a full informational spectral representation for nonlinear and non-stationary data

Norden E. Huang, Kun Hu, Albert C. C. Yang, Hsing-Chih Chang, Deng Jia, Wei-Kuang Liang, Jia Rong Yeh, Chu-Lan Kao, Chi-Hung Juan, Chung Kang Peng, Johanna H. Meijer, Yung-Hung Wang (+2 others)
2016 Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences  
One contribution of 13 to a theme issue 'Adaptive data analysis: theory and applications' .  ...  N.E.H. thanks Professor Fangli Qiao for trying the new spectral analysis on wave-turbulence interaction data and sharing his unpublished manuscript.  ...  Now, with each additional layer of decomposition on the amplitude envelope functions, a jk (t), a jkl ( The HHS for the multiplicative data.  ... 
doi:10.1098/rsta.2015.0206 pmid:26953180 pmcid:PMC4792412 fatcat:xrvfp6c2mbddlnsliyamwpaiga

Robust Flutter Margins of an F/A-18 Aircraft from Aeroelastic Flight Data

Rick Lind, Marty Brenner
1997 Journal of Guidance Control and Dynamics  
Flight data can be used to validate the robust system model and increase accuracy of the utter margin estimate.  ...  Extensive ight data from conditions throughout the ight envelope are analyzed to determine the levels of uncertainty in a theoretical model.  ...  Analysis of the nite element model was assisted by Tim Doyle and Roger Truax.  ... 
doi:10.2514/2.4082 fatcat:xfjz6x6fgzfyfalkutfax2b3ca

Wavelet-Processed Flight Data for Robust Aeroservoelastic Stability Margins

Marty Brenner, Rick Lind
1998 Journal of Guidance Control and Dynamics  
The conservatism of the robust stability margins is reduced with parametric and nonparametric time-frequency analysis of ight data in the model validation process.  ...  Wavelet analysis for ltering and system identi cation is used to improve the estimation of aeroservoelasti c (ASE) stability margins.  ...  Multiresolution analysis advances this capability with the discrete wavelet transform (DWT) to decompose the data into multiple scales to reveal prominent and subtle features regardless of the governing  ... 
doi:10.2514/2.4331 fatcat:rhr3i4erozdgvfuh4wlo5d7wva

Flutter Margins for Multimode Unstable Couplings with Associated Flutter Confidence

Rick Lind
2009 Journal of Aircraft  
The approach has assisted envelope expansion for many flight tests; however, it is limited to consideration of 2-mode coupling for the flutter instability.  ...  Flutter margins are computed for a modified 747 aircraft with a 4mode instability to show that the multi-mode approach with associated confidence is able to accurately predict the onset of flutter.  ...  She provided the data from p-k analysis along with insight into the nature of the flutter mechanism.  ... 
doi:10.2514/1.40328 fatcat:3lt22k7nkrfg3gbphpuwbt2zvq

Oscillation mode identification based on wide-area ambient measurements using multivariate empirical mode decomposition

Shutang You, Jiahui Guo, Gefei Kou, Yong Liu, Yilu Liu
2016 Electric power systems research  
There are two main categories of methods for oscillation analysis based on ambient and event data: transfer function based methods and subspace methods.  ...  Transfer-function-based methods directly estimate mode shape through treating measurements as system outputs.  ...  This synchronized approach helps to identify the oscillation modes that exists in multiple channels with low amplitudes, which may be neglected in mono-channel analysis [49] .  ... 
doi:10.1016/j.epsr.2016.01.012 fatcat:f4ag5axjpjbudh5zdvrekuhne4

Providing a new three stage data envelopment analysis model (DEA) in fuzzy environment

Saeideh Naderi, Samaneh Daroudi, Saeid Batouyi
2018 Data Envelopment Analysis and Decision Science  
The data envelopment analysis models (DEA) are provided to measure set of relative efficiency from decision making unit with different inputs to make different outputs.  ...  For a discussion of inaccurate data, the fuzzy concept is introduced .it is main objective of this paper to provide a new method for evaluating the efficiency in method of network data envelopment analysis  ...  Data envelopment analysis models deal with decision-making units like the "black box".  ... 
doi:10.5899/2018/dea-00156 fatcat:657rzpyikzhepknvqmi7jsbp3i

Research on Local Mean Decomposition Algorithms in Harmonic and Voltage Flicker Detection of Microgrid

Wensi CAO, Linfei LIU
2013 Sensors & Transducers  
the local characteristics of PF data, the method can be accurate analysis of multi frequency harmonic distortion signal, interharmonic signal and multiple frequency voltage flicker signal.  ...  According to the actual analysis of a transformer with multi-frequency signal power in a microgrid system, using LMD algorithm and HHT algorithm, The result further prove the correctness of the proposed  ...  Acknowledgment This work is supported by the Natural Science Foundation of the Education Department of Henan Province (12A470005).  ... 
doaj:d26acb7ee8184d3598e3b1651884fb1f fatcat:rw24mzwfffckjhnhxej6tohqou

Incorporating Flight Data into a Robust Aeroelastic Model

Rick Lind, Marty Brenner
1998 Journal of Aircraft  
Stability analysis and control synthesis for high-performance aircraft must account for errors in the aircraft model.  ...  This paper introduces a method to update a theoretical model using measured ight data.  ...  Acknowledgments The authors acknowledge the nancial support of the Structures Branch of NASA at Dryden Flight Research Center.  ... 
doi:10.2514/2.2320 fatcat:5mwqft4vmbdtbbgkcp3vclq3qm

The Fault Diagnosis Research of Gearbox Based on Hilbert-Huang Transform

Fengcai Cao, Hongxia Pan
2012 International Journal of Education and Management Engineering  
Tests showed that, the marginal spectrum based on Hilbert-Huang transform can get the characteristics of fault signal frequency of the gearbox, thus it can identify the type of gearbox fault effectively  ...  In this paper we aim at the engineering need of gearbox real-time monitoring and fault diagnosis, expanding a study of JZQ250 Gear Box.  ...  However, almost every signal data to analyze is not intrinsic mode function, at any point in time, the signal data may include multiple wave modes, so long report that a simple Hilbert transform signal  ... 
doi:10.5815/ijeme.2012.04.12 fatcat:db27dxmpxrb2lnhztnahdla5zi

EEMD-Based Speaker Automatic Emotional Recognition in Chinese Mandarin

Yuqiang Qin, Yudong Qi
2014 Applied Mathematics & Information Sciences  
Emotional intrinsic mode functions(IMFe) are obtained by empirical mode decomposition on emotional speech signals, the fast fourier transform(FFT) of each intrinsic mode function is extracted as the emotional  ...  It is acknowledged that human can communicate effectively with each other through the telephony system.  ...  EEMD can overcome the limitations of standard EMD when dealing with data from multiple sources. It is used to extract the intrinsic mode functions (IMFs) embedded in raw multivariate signals.  ... 
doi:10.12785/amis/080219 fatcat:onvtmjmk4jc2tm7ob7wi466rcy

Phase Time and Envelope Time in Time‐Distance Analysis and Acoustic Imaging

Dean‐Yi Chou, Thomas L. Duvall, Jr.
2000 Astrophysical Journal  
The location of the envelope peak of the cross-correlation function in time-distance analysis is identiÐed as the travel time of the wave packet formed by modes with the same horizontal phase velocity.  ...  The envelope peak of the crosscorrelation function between constructed ingoing and outgoing time series is located at zero time, as predicted for one-bounce results at 3 mHz for all four data sets and  ...  We are grateful to the GONG Data Team for providing the software package GRASP. D.-Y. C. deeply thanks all members of the TON Team who were dedicated to the long-term observation.  ... 
doi:10.1086/308655 fatcat:2fksvqayg5gmvjixpaa2agk334
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