scholarly journals Rare Event Estimation Using Polynomial-Chaos Kriging

Author(s):  
R. Schöbi ◽  
B. Sudret ◽  
S. Marelli
Keyword(s):  
Processes ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 185 ◽  
Author(s):  
Patrick Piprek ◽  
Sébastien Gros ◽  
Florian Holzapfel

This study develops a ccoc framework capable of handling rare event probabilities. Therefore, the framework uses the gpc method to calculate the probability of fulfilling rare event constraints under uncertainties. Here, the resulting cc evaluation is based on the efficient sampling provided by the gpc expansion. The subsim method is used to estimate the actual probability of the rare event. Additionally, the discontinuous cc is approximated by a differentiable function that is iteratively sharpened using a homotopy strategy. Furthermore, the subsim problem is also iteratively adapted using another homotopy strategy to improve the convergence of the Newton-type optimization algorithm. The applicability of the framework is shown in case studies regarding battery charging and discharging. The results show that the proposed method is indeed capable of incorporating very general cc within an ocp at a low computational cost to calculate optimal results with rare failure probability cc.


2011 ◽  
Author(s):  
Shu-cheng Steve Chi ◽  
Shu-chen Chen ◽  
Ray Friedman
Keyword(s):  

2020 ◽  
Vol 39 (6) ◽  
pp. 8463-8475
Author(s):  
Palanivel Srinivasan ◽  
Manivannan Doraipandian

Rare event detections are performed using spatial domain and frequency domain-based procedures. Omnipresent surveillance camera footages are increasing exponentially due course the time. Monitoring all the events manually is an insignificant and more time-consuming process. Therefore, an automated rare event detection contrivance is required to make this process manageable. In this work, a Context-Free Grammar (CFG) is developed for detecting rare events from a video stream and Artificial Neural Network (ANN) is used to train CFG. A set of dedicated algorithms are used to perform frame split process, edge detection, background subtraction and convert the processed data into CFG. The developed CFG is converted into nodes and edges to form a graph. The graph is given to the input layer of an ANN to classify normal and rare event classes. Graph derived from CFG using input video stream is used to train ANN Further the performance of developed Artificial Neural Network Based Context-Free Grammar – Rare Event Detection (ACFG-RED) is compared with other existing techniques and performance metrics such as accuracy, precision, sensitivity, recall, average processing time and average processing power are used for performance estimation and analyzed. Better performance metrics values have been observed for the ANN-CFG model compared with other techniques. The developed model will provide a better solution in detecting rare events using video streams.


2017 ◽  
Vol 188 (01) ◽  
pp. 106-112 ◽  
Author(s):  
S.K. Nechaev ◽  
K. Polovnikov

2014 ◽  
Vol 23 (3) ◽  
pp. 321-324 ◽  
Author(s):  
Sorinel Lunca ◽  
Vlad Porumb ◽  
Natalia Velenciuc ◽  
Dan Ferariu ◽  
Gabriel Dimofte

A solitary Peutz-Jeghers polyp is defined as a unique polyp occurring without associated mucocutaneous pigmentation or a family history of Peutz-Jeghers syndrome. Gastric solitary localization is a rare event, with only eight reported cases to date. We report herein the case of a 43-year old woman who presented with upper gastrointestinal bleeding, severe anemia, weight loss and asthenia. Endoscopy revealed a giant polypoid tumor with signs of neoplastic invasion of the cardia, with pathological aspect suggesting a Peutz-Jeghers hamartomatous polyp. Computed tomography suggested a malignant gastric tumor and a total gastrectomy was performed. The pathological specimen showed a giant 150/70/50 mm polypoid tumor and immunochemistry established the final diagnostic of a Peutz-Jegers type polyp. This is the largest solitary Peutz-Jeghers gastric polyp reported until now, and the second one mimicking a gastric malignancy with lymph node metastasis.


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