the frequency response analysis (fra) test has been recognized as one of the sensitive tools available for detecting electrical and mechanical faults inside power transformers. however, there is still no universally systematic interpretation technique for these tests. many research efforts have employed different statistical criteria in order to aid the interpretative capability of the fra, but...

frequency response analysis (fra) is popular technique which has been used since the last decade as a diagnostic method for transformers. however, accurate interpretation of fra measurements is still challenging. recent studies reveal that apart from winding deformation, fra data can also be influenced by moisture variation in transformer paper insulation. hence, a specific transformer’s model ...

this paper explains a model for analyzing and measuring the propagation of order amplifications (i.e. bullwhip effect) for a single-product supply network topology considering exogenous uncertainty and linear and time-invariant inventory management policies for network entities. the stream of orders placed by each entity of the network is characterized assuming customer demand is ergodic. in fa...

The difficulty of selecting the optimal time-frequency distribution (TFD) for a given real-life signal has been one of the major limiting factors to a wider use of time-frequency analysis tools in practice. This paper, by extending our earlier works on the objective assessment of the performance of TFDs, presents a novel automatic approach for selecting a real-life signal best-performing time-f...

In this paper, a fully polarimetric time-frequency analysis method is introduced to decompose synthesized polarimetric and interferometric SAR images into range-frequency and azimuth-frequency domain. This 4-D representation permits to characterize the frequency response of the scene reflectivity, observed under different azimuth look-angles. A statistical analysis of polarimetric parameters pe...

We present an efficient method for robustly calculating time-frequency attributes of a signal, including instantaneous mean frequency, bandwidth, and kurtosis. Most current approaches involve a costly intermediate step of computing a (highly oversampled) 2-d bilinear time-frequency representation (TFR), which is then collapsed to the I-d attribute. Using the principles of hybrid linearhilinear ...

We introduce a new and simple technique for human gait classification based on the time-frequency analysis of radar data. The focus is on the classification of arm movements to discern free vs. confined arm swinging motion. The latter may arise in hostage situation or may be indicative to carrying objects with one or both hands. The motion signatures corresponding to the arm and leg movements a...

The Modal distribution is a time-frequency distribution specifically designed to model the quasi-harmonic, multi-sinusoidal, nature of music signals and belongs to the Cohen general class of time-frequency distributions. A streaming, object-oriented implementation of the Modal distribution is presented which forms the basis for designing other members of the Cohen class. Implementation of this ...