Author name cluster

Kewen Wang 0001

Possible papers associated with this exact author name in Arrow. This page groups case-insensitive exact name matches and is not a full identity disambiguation profile.

6 papers

1 author row

ECAI Conference 2024 Conference Paper

Differentiating Choices via Commonality for Multiple-Choice Question Answering

Wenqing Deng
Zhe Wang 0001
Kewen Wang 0001
Shirui Pan
Xiaowang Zhang
Zhiyong Feng 0002

Multiple-choice question answering (MCQA) becomes particularly challenging when all choices are relevant to the question and are semantically similar. Yet this setting of MCQA can potentially provide valuable clues for choosing the right answer. Existing models often rank each choice separately, overlooking the context provided by other choices. Specifically, they fail to leverage the semantic commonalities and nuances among the choices for reasoning. In this paper, we propose a novel MCQA model by differentiating choices through identifying and eliminating their commonality, called DCQA. Our model captures token-level attention of each choice to the question, and separates tokens of the question attended to by all the choices (i. e. , commonalities) from those by individual choices (i. e. , nuances). Using the nuances as refined contexts for the choices, our model can effectively differentiate choices with subtle differences and provide justifications for choosing the correct answer. We conduct comprehensive experiments across five commonly used MCQA benchmarks, demonstrating that DCQA consistently outperforms baseline models. Furthermore, our case study illustrates the effectiveness of the approach in directing the attention of the model to more differentiating features.

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ECAI Conference 2020 Conference Paper

Lifting Majority to Unanimity in Opinion Diffusion

Zhiqiang Zhuang
Kewen Wang 0001
Junhu Wang
Heng Zhang 0006
Zhe Wang 0001
Zhiguo Gong

In this paper, we study an information exchange process in which a network of individuals exchanges a binary opinion. In the process, the individuals change their opinions only if a majority of their neighbours have the opposite opinion and they do it synchronously. Motivated by applications in multiagent systems, distributed computing, and social science, our goal is to derive graph-theoretic features of the network that guarantee whenever a majority of individuals initially have the same opinion, they will eventually spread the opinion to all individuals. We tackle the problem by first introducing a graph-theoretic notion called controlling set which is capable of characterising the information exchange process and, by exploiting the notion, we obtain a series of lower and upper bounds on the in-degree of vertices as well as lower bound on the size of certain neighbourhoods for guaranteeing the majority to unanimity behaviour.

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JELIA Conference 2016 Conference Paper

Revising Possibilistic Knowledge Bases via Compatibility Degrees

Yifan Jin
Kewen Wang 0001
Zhe Wang 0001
Zhiqiang Zhuang

Abstract Possibilistic logic is a weighted logic for dealing with incomplete and uncertain information by assigning weights to propositional formulas. A possibilistic knowledge base (KB) is a finite set of such formulas. The problem of revising a possibilistic KB by possibilistic formula is not new. However, existing approaches are limited in two ways. Firstly, they suffer from the so-called drowning effect. Secondly, they handle certain and uncertain formulas separately and most only handle certain inputs. In this paper, we propose a unified approach that caters for revision by both certain and uncertain inputs and relieves the drowning effect. The approach is based on a refined inconsistency degree function called compatibility degree which provides a unifying framework (called cd-revision) for defining specific revision operators for possibilistic KBs. Our definition leads to an algorithm for computing the result of the proposed revision. The revision operators defined in cd-revision possess some desirable properties including those from classic belief revision and some others that are specific to possibilistic revision. We also show that several major revision operators for possibilistic, stratified and prioritised KBs can be embedded in cd-revision.

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LPAR Conference 2012 Conference Paper

Forgetting for Defeasible Logic

Grigoris Antoniou
Thomas Eiter
Kewen Wang 0001

Abstract The concept of forgetting has received significant interest in artificial intelligence recently. Informally, given a knowledge base, we may wish to forget about (or discard) some redundant parts (such as atoms, predicates, concepts, etc) but still preserve the consequences for certain forms of reasoning. In nonmonotonic reasoning, so far forgetting has been studied only in the context of extension based approaches, mainly answer-set programming. In this paper forgetting is studied in the context of defeasible logic, which is a simple, efficient and sceptical nonmonotonic reasoning approach.

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ECAI Conference 2010 Conference Paper

Tableau-based Forgetting in [Ascr ][Lscr ][Cscr ] Ontologies

Zhe Wang 0001
Kewen Wang 0001
Rodney W. Topor
Xiaowang Zhang

In this paper, we propose two new approaches to forgetting for [Ascr ][Lscr ][Cscr ] based on the well-known tableau algorithm. The first approach computes the result of forgetting by rolling up tableaux, and also provides a decision algorithm for the existence of forgetting in [Ascr ][Lscr ][Cscr ]. When the result of forgetting does not exist, we provide an incremental method for computing approximations of forgetting. This second approach uses variable substitution to refine approximations of forgetting and eventually obtain the result of forgetting. This approach is capable of preserving structural information of the original ontologies enabling readability and comparison. As both approaches are based on the tableau algorithm, their implementations can make use of the mechanisms and optimization techniques of existing description logic reasoners.

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NMR Workshop 2002 Conference Paper

Preferred well-founded semantics for logic programming by alternating fixpoints: preliminary report

Torsten Schaub
Kewen Wang 0001

We analyze the problem of defining wellfounded semantics for ordered logic programs within a general framework based on alternating fixpoint theory. We start by showing that generalizations of existing answer set approaches to preference are too weak in the setting of wellfounded semantics. We then specify some informal yet intuitive criteria and propose a semantical framework for preference handling that is more suitable for defining well-founded semantics for ordered logic programs. The suitability of the new approach is convinced by the fact that many attractive properties are satisfied by our semantics. In particular, our semantics is still correct with respect to various existing answer sets semantics while it successfully overcomes the weakness of their generalization to well-founded semantics. Finally, we indicate how an existing preferred well-founded semantics can be captured within our semantical framework.

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