Jun Liu

Prof. Jun Liu


Research Focus & Metrics

Academic Career Length

27Years (2000-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
21 February 2006 in IEEE Transactions on Systems, Man, and Cybernetics - Part A: Systems and Humans
Verified
Journal Article
Closed access
JYJian-Bo Yang
Jian-Bo Yang
JLJun Liu
Jun Liu
JWJin Wang
Jin Wang
HSHow-Sing Sii
How-Sing Sii
HWHong-Wei Wang
Hong-Wei Wang
In this paper, a generic rule-base inference methodology using the evidential reasoning (RIMER) approach is proposed. Existing knowledge-base structures are first examined, and knowledge representation schemes under uncertainty are then briefly analyzed. Based on this analysis, a new knowledge representation scheme in a rule base is proposed using a belief structure. In this scheme, a rule base is designed with belief degrees embedded in all possible consequents of a rule. Such a rule base is capable of capturing vagueness, incompleteness, and nonlinear causal relationships, while traditional if-then rules can be represented as a special case. Other knowledge representation parameters such as the weights of both attributes and rules are also investigated in the scheme. In an established rule base, an input to an antecedent attribute is transformed into a belief distribution. Subsequently, inference in such a rule base is implemented using the evidential reasoning (ER) approach. The scheme is further extended to inference in hierarchical rule bases. A numerical study is provided to illustrate the potential applications of the proposed methodology.

1 May 2011 in Automatica
Verified
Journal Article
Closed access
JLJun Liu
Jun Liu
XLXinzhi Liu
Xinzhi Liu
WXWei-Chau Xie
Wei-Chau Xie

1 January 2007 in Expert Systems with Applications
Verified
Journal Article
Closed access
DXDong-Ling Xu
Dong-Ling Xu
JLJun Liu
Jun Liu
JYJian-Bo Yang
Jian-Bo Yang
GLGuoping Liu
Guoping Liu
JWJin Wang
Jin Wang
JRJun Ren
Jun Ren

18 June 2007 in IEEE Transactions on Systems, Man, and Cybernetics - Part A: Systems and Humans
Verified
Journal Article
Closed access
JYJian-Bo Yang
Jian-Bo Yang
JLJun Liu
Jun Liu
DXDong-Ling Xu
Dong-Ling Xu
JWJin Wang
Jin Wang
HWHongwei Wang
Hongwei Wang
A belief rule-base inference methodology using the evidential reasoning approach (RIMER) has been developed recently, where a new belief rule representation scheme is proposed to extend traditional IF-THEN rules. The belief rule expression matrix in RIMER provides a compact framework for representing expert knowledge. However, it is difficult to accurately determine the parameters of a belief rule base (BRB) entirely subjectively, particularly, for a large-scale BRB with hundreds or even thousands of rules. In addition, a change in rule weight or attribute weight may lead to changes in the performance of a BRB. As such, there is a need to develop a supporting mechanism that can be used to train, in a locally optimal way, a BRB that is initially built using expert knowledge. In this paper, several new optimization models for locally training a BRB are developed. The new models are either single- or multiple-objective nonlinear optimization problems. The main feature of these new models is that only partial input and output information is required, which can be either incomplete or vague, either numerical or judgmental, or mixed. The models can be used to fine tune a BRB whose internal structure is initially decided by experts' domain-specific knowledge or common sense judgments. As such, a wide range of knowledge representation schemes can be handled, thereby facilitating the construction of various types of BRB systems. Conclusions drawn from such a trained BRB with partially built-in expert knowledge can simulate real situations in a meaningful, consistent, and locally optimal way. A numerical study for a hierarchical rule base is examined to demonstrate how the new models can be implemented as well as their potential applications.

1 April 2008 in Computers & Industrial Engineering
Verified
Journal Article
Closed access
YWYing-Ming Wang
Ying-Ming Wang
JLJun Liu
Jun Liu
TETaha M.S. Elhag
Taha M.S. Elhag

7 February 2013 in IEEE Transactions on Automatic Control
Verified
Journal Article
Closed access
JLJun Liu
Jun Liu
NONecmiye Ozay
Necmiye Ozay
UTUfuk Topcu
Ufuk Topcu
RMRichard M. Murray
Richard M. Murray
We propose formal means for synthesizing switching protocols that determine the sequence in which the modes of a switched system are activated to satisfy certain high-level specifications in linear temporal logic (LTL). The synthesized protocols are robust against exogenous disturbances on the continuous dynamics and can react to possibly adversarial events (both external and internal). Finite-state approximations that abstract the behavior of the underlying continuous dynamics are defined using finite transition systems. Such approximations allow us to transform the continuous switching synthesis problem into a discrete synthesis problem in the form of a two-player game between the system and the environment, where the winning conditions represent the high-level temporal logic specifications. Restricting to an expressive subclass of LTL formulas, these temporal logic games are amenable to solutions with polynomial-time complexity. By construction, existence of a discrete switching strategy for the discrete synthesis problem guarantees the existence of a switching protocol that can be implemented at the continuous level to ensure the correctness of the nonlinear switched system and to react to the environment at run time.