Search

Your search keyword '"He, Sijun"' showing total 11 results
Start Over Author "He, Sijun"

Refine your results

more »

more »

more »
11 results on '"He, Sijun"'

2. Assessing Demographic Bias in Named Entity Recognition

Author

Mishra, Shubhanshu, He, Sijun, and Belli, Luca

Subjects
Computer Science - Computation and Language, Computer Science - Computers and Society, Computer Science - Information Retrieval, Computer Science - Machine Learning, 68T50 (Primary), 68T30 (Secondary), 68U15, I.2.7, I.2.1, I.2.6, H.3.1, H.3.3, H.1.2, K.4.2
Abstract

Named Entity Recognition (NER) is often the first step towards automated Knowledge Base (KB) generation from raw text. In this work, we assess the bias in various Named Entity Recognition (NER) systems for English across different demographic groups with synthetically generated corpora. Our analysis reveals that models perform better at identifying names from specific demographic groups across two datasets. We also identify that debiased embeddings do not help in resolving this issue. Finally, we observe that character-based contextualized word representation models such as ELMo results in the least bias across demographics. Our work can shed light on potential biases in automated KB generation due to systematic exclusion of named entities belonging to certain demographics., Comment: Presented at the AKBC Workshop on Bias in Automatic Knowledge Graph Construction, 2020 (arXiv:2007.11659)

Published
2020

4. Satisfaction Evaluation of the Passenger Interface Design of High-Speed Train Based on G1-Entropy Weight Method

Author

He, Sijun, Zhi, Jinyi, Xiang, Zerui, Kacprzyk, Janusz, Series Editor, Pal, Nikhil R., Advisory Editor, Bello Perez, Rafael, Advisory Editor, Corchado, Emilio S., Advisory Editor, Hagras, Hani, Advisory Editor, Kóczy, László T., Advisory Editor, Kreinovich, Vladik, Advisory Editor, Lin, Chin-Teng, Advisory Editor, Lu, Jie, Advisory Editor, Melin, Patricia, Advisory Editor, Nedjah, Nadia, Advisory Editor, Nguyen, Ngoc Thanh, Advisory Editor, Wang, Jun, Advisory Editor, Ahram, Tareq, editor, and Falcão, Christianne, editor

Published
2020
Full Text
View/download PDF

6. Formability enhancement for tailor-welded blanks using blank holding force control

Author

He, Sijun, Wu, Xin, and Hu, S. Jack

Subjects
Sheet-metal -- Research, Engineering and manufacturing industries, Science and technology
Abstract

Tailor-welded blanks (TWB) are widely used for stamped auto body panels because of their great benefits in weight and cost reduction. However, the weld line in a tailor-welded blank causes serious concerns in formability because of material discontinuity and additional inhomogeneous stress/strain distribution. This paper proposes a blank homing force (BHF) control strategy to control the weld line movement, distribute the deformation more uniformly and thereby improve TWB formability. The control methodology is developed based on a simplified 2-D sectional analytical model that estimates the stress/strain distribution and the BHFs required for each side of the flange with dissimilar materials. The model can be further extended to 3-D analysis by superimposing the 2-D sectional analysis results around the entire binder ring and thus determining the required BHF for the whole panel. Finite element simulations are performed to study the effects of forming parameters on the weld line movement. Experiments have been conducted to verify the analytical model and partial finite element simulations. Both analysis and experiments demonstrated that a lower BHF should be applied on the thicker blank side to allow more metal to flow-in for obtaining more uniform strain distribution. The proposed BHF control is proven to be a good approach to enhancing TWB formability.

Published
2003

11. Formability enhancement for tailor -welded blanks.

Author

He, Sijun

Subjects
Formability Enhancement, Sheet Metal Forming, Tailor-welded Blanks
Abstract

The revolutionary concept of tailor-welded blanks (TWB) was introduced into the automotive industry in the earlier 1980's. The number of TWB panels has grown significantly in the recent years because of their great benefits. The most important benefit of TWB is that it distributes the weight or the special material to the place exactly it is needed. However, technical challenge exists in forming TWB: in general, forming non-homogeneous blanks narrows the formability window, and it causes undesired weld line movement. To date both fundamental understanding and practical solution to the formability and weld line movement control are still ambiguous. In this thesis, a simplified model has been developed to analyze the deformation of TWB under uniaxial tensile loading and with orientated weld line. In addition to material properties, the strain/stress distribution in TWB has been found also related to the geometrical configuration of the specimen, for example, the weld line orientation and base metal length ratio. Such configuration dependence of TWB has been summarized and general guidelines for designing TWB have been obtained. This thesis then proposes two methodologies to control the weld line movement in order to improve the TWB formability. One is using blank holding force (BHF) control and the other is using drawbead design. A simplified 2-D analytical model has been developed to estimate the stress/strain distribution and the required BHF or drawbead restraining force (DBRF) for different base metal sides. The model can be further extended to 3-D cases by superimposing the 2-D section analysis results around the entire binder ring. The required BHF or DBRF level is related to the geometry profile and determined by the friction force and bending force developed for each base metal side. Finite element simulations and experiments have been conducted to verify the proposed control methodologies. As a result, the proposed BHF control strategy and drawbead design are proved to be effective in controlling the weld line movement and enhancing the TWB formability.

Published
2001

Catalog

Books, media, physical & digital resources
See catalog results