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Analyzing position bias in question answering system

Analyzing position bias in question answering system

Material type
학위논문
Personal Author
고미영, 高美煐
Title Statement
Analyzing position bias in question answering system / Miyoung Ko
Publication, Distribution, etc
Seoul :   Graduate School, Korea University,   2020  
Physical Medium
iv, 22장 : 도표 ; 26 cm
기타형태 저록
Analyzing Position Bias in Question Answering System   (DCOLL211009)000000232146  
학위논문주기
학위논문(석사)-- 고려대학교 대학원: 컴퓨터·전파통신공학과, 2020. 8
학과코드
0510   6D36   1117  
General Note
지도교수: 강재우  
Bibliography, Etc. Note
참고문헌: 장 18-22
이용가능한 다른형태자료
PDF 파일로도 이용가능;   Requires PDF file reader(application/pdf)  
비통제주제어
Question Answering,,
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100 1 ▼a 고미영, ▼g 高美煐
245 1 0 ▼a Analyzing position bias in question answering system / ▼d Miyoung Ko
260 ▼a Seoul : ▼b Graduate School, Korea University, ▼c 2020
300 ▼a iv, 22장 : ▼b 도표 ; ▼c 26 cm
500 ▼a 지도교수: 강재우
502 0 ▼a 학위논문(석사)-- ▼b 고려대학교 대학원: ▼c 컴퓨터·전파통신공학과, ▼d 2020. 8
504 ▼a 참고문헌: 장 18-22
530 ▼a PDF 파일로도 이용가능; ▼c Requires PDF file reader(application/pdf)
653 ▼a Question Answering
776 0 ▼t Analyzing Position Bias in Question Answering System ▼w (DCOLL211009)000000232146
900 1 0 ▼a Ko, Mi-young, ▼e
900 1 0 ▼a 강재우, ▼e 지도교수
945 ▼a KLPA

Electronic Information

No. Title Service
1
Analyzing position bias in question answering system (25회 열람)
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Holdings Information

No. Location Call Number Accession No. Availability Due Date Make a Reservation Service
No. 1 Location Science & Engineering Library/Stacks(Thesis)/ Call Number 0510 6D36 1117 Accession No. 123064864 Availability Available Due Date Make a Reservation Service B M
No. 2 Location Science & Engineering Library/Stacks(Thesis)/ Call Number 0510 6D36 1117 Accession No. 123064865 Availability Available Due Date Make a Reservation Service B M

Contents information

Abstract

Many extractive question answering models are trained to predict start and end positions of answers.
The choice of predicting answers as positions is mainly due to its simplicity and effectiveness.
In this study, we hypothesize that when the distribution of the answer positions is highly skewed in the training set (e.g., answers lie only in the $k$-th sentence of each passage), QA models predicting answers as positions learn spurious positional cues and fail to give answers in different positions.
We first illustrate this \textit{position bias} in popular extractive QA models such as BiDAF and BERT and thoroughly examine how position bias propagates through each layer of BERT.
To safely deliver position information without position bias, we train models with various de-biasing methods including entropy regularization and randomized position.
We found that reducing correlation between word positions and answers helps us to resolve position bias.

Table of Contents

Abstract
Contents i
List of Figures iii
List of Tables iv
1  Introduction 1
2  Related Work 4
3  Analyzing Position Bias 6
3.1    Position Bias on Synthetic Datasets   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .6
3.2    Visualization of Position Bias  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .7
3.3    Generalizing to Different Positions   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .11
4  De-biasing Position Bias12
4.1    Method   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .12
4.1.1Entropy Regularization   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .12
4.1.2Randomized Position .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .13
4.2    Experiments .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .13
4.2.1Implementation Details   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .13
4.2.2Results   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .13
5  Discussion 15
6  Conclusion 17
Bibliography 18