UNCERTAIN DATA PROCESSING AND APPLICATIONS

The Hong Kong University of Science and Technology
Department of Computer Science and Engineering


PhD Thesis Defence


Title: "UNCERTAIN DATA PROCESSING AND APPLICATIONS"

By

Mr. Zhou ZHAO


Abstract

Data uncertainty is inherent in many important real-world applications 
such as RFID tracking, expert finding and user tagging. In this thesis, we 
study the problem of reducing uncertainty via missing value estimation.

We first study the problem of RFID tracking in the mobile environment. The 
challenging of RFID tracking is missing reading, where the read rate of 
RFID data in the real-world is often in the range of 60-70%. We propose a 
probabilistic model for RFID tracking in the mobile environment via 
missing value estimation. We take advantage of the spatiotemporal 
correlation of tracked objects for addressing the problem.

We next study the problem of expert finding for question answering in the 
social networks. In order to provide high-quality experts, we have to 
obtain sufficient amount of past activities to infer the model. However, 
the past activities in most social network systems are rather few, and 
thus the user model may not be well inferred in practice. We consider the 
problem of expert finding from the viewpoint of missing value estimation. 
We then employ users' social networks for inferring user model, and thus 
improve the performance of expert finding in CQA systems.

We then study the problem of user tagging in the social networks. Unlike 
previous studies based on matrix factorization or probabilistic modelling, 
we propose and study the problem of user tagging from missing value 
estimation via collaborative tag function learning. In this learning 
approach, we learn the collaborative tag functions based on users' social 
activities in a microblogging system and their social connections. To 
avoid social spams on microblogging systems, we introduce a structured 
l2,1-norm regularizer for learning the tag functions robustly.


Date:			Friday, 30 January 2015

Time:			2:00pm - 4:00pm

Venue:			Room 3494
 			Lifts 25/26

Chairman:		Prof. Hong-Kam Lo (CIVL)

Committee Members:	Prof. Wilfred Ng (Supervisor)
 			Prof. Shing-Chi Cheung
 			Prof. Nevin Zhang
 			Prof. Wai-Ho Mow (ECE)
 			Prof. Qing Li (Comp. Sci., CityU)


**** ALL are Welcome ****