Prognosis of Failure Precursor in Complex Electrical Systems Using Symbolic Dynamics

Author(s):  
Ravindra Patankar ◽  
Venkatesh Rajagopalan ◽  
Devendra Tolani ◽  
Asok Ray ◽  
Michael Begin
2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Li-Feng Wu ◽  
Yong Guan ◽  
Xiao-Juan Li ◽  
Jie Ma

The MOSFET is an important power electronic transistor widely used in electrical systems. Its reliability has an effect on the performance of systems. In this paper, the failure models and mechanisms of MOSFETs are briefly analyzed. The on-resistanceRonis the key failure precursor parameter representing the degree of degradation. Based on the experimental data, a nonlinear dual-exponential degradation model for MOSFETs is obtained. Then, we present an approach for MOSFET degradation state prediction using a strong tract filter based on the obtained degradation model. Lastly, the proposed algorithm is shown to perform effectively on experimental data. Thus, it can provide early warning and enhance the reliability of electrical systems.


Methodology ◽  
2011 ◽  
Vol 7 (3) ◽  
pp. 88-95 ◽  
Author(s):  
Jose A. Martínez ◽  
Manuel Ruiz Marín

The aim of this study is to improve measurement in marketing research by constructing a new, simple, nonparametric, consistent, and powerful test to study scale invariance. The test is called D-test. D-test is constructed using symbolic dynamics and symbolic entropy as a measure of the difference between the response patterns which comes from two measurement scales. We also give a standard asymptotic distribution of our statistic. Given that the test is based on entropy measures, it avoids smoothed nonparametric estimation. We applied D-test to a real marketing research to study if scale invariance holds when measuring service quality in a sports service. We considered a free-scale as a reference scale and then we compared it with three widely used rating scales: Likert-type scale from 1 to 5 and from 1 to 7, and semantic-differential scale from −3 to +3. Scale invariance holds for the two latter scales. This test overcomes the shortcomings of other procedures for analyzing scale invariance; and it provides researchers a tool to decide the appropriate rating scale to study specific marketing problems, and how the results of prior studies can be questioned.


Author(s):  
Regina Lamedica ◽  
Fabio Massimo Gatta ◽  
Alessandro Ruvio ◽  
Francesco Olevano ◽  
Guido Guidi Buffarini ◽  
...  

2020 ◽  
Vol 10 (10) ◽  
pp. 44-51
Author(s):  
Yury Yu. SKOROKHOD ◽  
◽  
Sehgey I. VOL’SKIY ◽  

The power circuit arrangements of on-board high-voltage static converters fed from a 3000 V AC single-phase network that in the general case produce multi-channel AC and DC output voltages are considered. The basic technical requirements posed to such converters are formulated. The general structural diagram of high-voltage converters with improved electric power consumption quality is given. Possible power circuit arrangements for the high-voltage converter input unit based on single-phase input current correction devices are considered. A classification and criteria for comparative evaluation of the possible power circuit arrangements of these devices are proposed. The information presented in the article will be of interest for specialists engaged in designing on-board electrical systems involving high-voltage converters that must comply with strict requirements for the quality of consumed single-phase input current.


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