ParisTech

About: ParisTech is a education organization based out in Paris, France. It is known for research contribution in the topics: Finite element method & Residual stress. The organization has 1888 authors who have published 1965 publications receiving 55532 citations. The organization is also known as: Paris Institute of Technology & ParisTech Développement.

A Method for Hot Spot Temperature Prediction of a 10 kV Oil-Immersed Transformer

Abstract: This paper proposed a prediction method to predict a 10-kV oil-immersed transformer hot spot temperature (HST). A set of feature temperature points on the transformer iron shell is proposed based on fluid-thermal field calculation. These feature points, as well as transformer load rate, are taken as the input parameters of a machine learning model established by support vector regression (SVR), thus to describe their relationships with the HST. This model is trained by nine samples selected by L9(34) orthogonal array and applied to predict the HST of 20 test samples. The training samples are all obtained by simulation, and the test samples have consisted of simulation and transformer temperature rise test results. With effective parameter optimization of the SVR model, the predicted results agree well with the experimental and simulation data, the mean absolute percentage error (MAPE) is 1.55%, and the maximum temperature difference is less than 3 °C. The results validated the validity and the generalization performance of the prediction model.

A detailed measurement of skype network traffic

Abstract: The last few years witnessed peer-2-peer (P2P) and VoIP telephony gaining a tremendous popularity: Skype is beyond doubt the most amazing example of this new phenomenon, as its 170 millions users testify. In this paper, we propose a detailed measurement of Skype sources: we adopt a twofold methodology, using active experiments and passive measurement to gain knowledge about the traffic Skype generates, in a controlled and realistic environment, respectively. The analysis considers both signaling traffic as well as voice calls. Furthermore, we address the description of Skype sources at both packet- and flow-levels: we describe fine-grained dynamics of the interaction between Skype and the network, as well as provide a macroscopic characterization of Skype traffic.

Experimental and numerical investigations of shock and shear wave propagation induced by femtosecond laser irradiation in epoxy resins

Abstract: In this work, original shock experiments are presented. Laser-induced shock and shear wave propagations have been observed in an epoxy resin, in the case of femtosecond laser irradiation. A specific time-resolved shadowgraphy setup has been developed using the photoelasticimetry principle to enhance the shear wave observation. Shear waves have been observed in epoxy resin after laser irradiation. Their propagation has been quantified in comparison with the main shock propagation. A discussion, hinging on numerical results, is finally given to improve understanding of the phenomenon.