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Liangda Fang

dblp:133/1691 · DBLP profile ↗
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46ranked-venue papers
13as first author
28since 2021 · last 2026
0000-0002-6435-6570ORCID · corroborated

Domains — the database's venue-derived domains; a paper can count in several

Artificial intelligence and machine learning · 35 · 12 first-author · 21 since 2021Graphics, computer vision, multimedia, augmented reality and games · 19 · 9 first-author · 10 since 2021Databases, data management, data science and information retrieval · 7 · 6 since 2021Human-computer interaction and ubiquitous computing · 3 · 2 since 2021Applied, interdisciplinary, general and emerging computing · 3 · 3 since 2021Systems, architecture and hardware · 2 · 1 first-authorSoftware engineering, systems software and programming languages · 1 · 1 since 2021Theory of computation · 1 · 1 first-author

Expertise — from the expertise taxonomy: the topics of the expert's papers under the CCF categories. A weight counts papers with recency: 1 for a paper about the topic, 0.3 when the topic is its context, halved every five years.

Theoretical computer science
18 papers
Logic in computer science · 31% Mathematical optimization · 25% Automated reasoning and model checking · 20%
Artificial intelligence
14 papers
Knowledge representation and reasoning · 40% Vision and language · 18% Planning, search and constraint satisfaction · 18%
Databases, data mining, and information retrieval
2 papers
Recommender systems · 50% Knowledge graphs · 27% Information retrieval · 23%
Interdisciplinary, comprehensive, and emerging computing
4 papers
Computational finance and economics · 43% Computing education · 32% Computational science and engineering · 25%

Topics — the 30 heaviest of 59, each with the papers that count most for it

TopicWeightPapersLastEvidence papers
Automated reasoning and model checking
knowledge compilation
1.732024
On the role of logical separability in knowledge compilation · Artif. Intell. 2024
Knowledge Compilation Meets Logical Separability · AAAI 2022
Knowledge Compilation in the Multi-Agent Epistemic Logic Kn · KR 2018
Mathematical optimization › continuous optimization › convex optimization › first-order methods › gradient-based optimization
subgradient method
1.622025
De-singularity Subgradient for the q-th-Powered lₚ-Norm Weber Location Problem · AAAI 2025
A De-singularity Subgradient Approach for the Extended Weber Location Problem · IJCAI 2024
Approximation and online algorithms › facility location
weber location problem
1.622025
De-singularity Subgradient for the q-th-Powered lₚ-Norm Weber Location Problem · AAAI 2025
A De-singularity Subgradient Approach for the Extended Weber Location Problem · IJCAI 2024
Knowledge, reasoning and agents › Knowledge representation and reasoning › reasoning about action and change › reasoning about actions
situation calculus
1.332025
A Syntactic Approach to Computing Complete and Sound Abstraction in the Situation Calculus · AAAI 2025
On the Progression of Knowledge and Belief for Nondeterministic Actions in the Situation Calculus · IJCAI 2015
Multiagent Knowledge and Belief Change in the Situation Calculus · AAAI 2013
Knowledge, reasoning and agents › Knowledge representation and reasoning › belief change
belief update
1.122024
On the Logic of Theory Change Iteration of KM-Update, Revised · IJCAI 2024
Dependence in Propositional Logic: Formula-Formula Dependence and Formula Forgetting - Application to Belief Update and Conservative Extension · AAAI 2018
Computer vision › Vision and language
multimodal reasoning
1.012026
Mitigating Evidence Suppression: Bi-level Active Evidence Injection for Educational Video Understanding · SIGIR 2026
Computer vision › Video understanding and tracking
video question answering
1.012026
Mitigating Evidence Suppression: Bi-level Active Evidence Injection for Educational Video Understanding · SIGIR 2026
Recommender systems › sequential recommendation
learning path recommendation
1.012026
GraphRAG-Induced Dual Knowledge Structure Graphs for Personalized Learning Path Recommendation · AAAI 2026
Logic in computer science
modal logic
0.942019
Disjunctive Normal Form for Multi-Agent Modal Logics Based on Logical Separability · AAAI 2019
Forgetting in Multi-Agent Modal Logics · IJCAI 2016
On the Progression of Knowledge and Belief for Nondeterministic Actions in the Situation Calculus · IJCAI 2015
Knowledge, reasoning and agents › Knowledge representation and reasoning › reasoning about action and change
action theories
0.912025
A Syntactic Approach to Computing Complete and Sound Abstraction in the Situation Calculus · AAAI 2025
Knowledge, reasoning and agents › Knowledge representation and reasoning › reasoning about action and change › reasoning about actions
basic action theory
0.912025
A Syntactic Approach to Computing Complete and Sound Abstraction in the Situation Calculus · AAAI 2025
Knowledge, reasoning and agents › Planning, search and constraint satisfaction › nondeterministic planning
conformant planning
0.912025
Improvements to the Generate-and-Complete Approach to Conformant Planning · IJCAI 2025
Natural language and speech › Language models and text generation › preference optimization
direct preference optimization
0.912025
Language Models as Implicit Tree Search · ICML 2025
Natural language and speech › Language models and text generation
preference optimization
0.912025
Language Models as Implicit Tree Search · ICML 2025
Knowledge, reasoning and agents › Planning, search and constraint satisfaction
tree search
0.912025
Language Models as Implicit Tree Search · ICML 2025
Recommender systems › domain-specific recommendation
exercise recommendation
0.912025
NR4DER: Neural Re-ranking for Diversified Exercise Recommendation · SIGIR 2025
Information retrieval › reranking
neural re-ranking
0.912025
NR4DER: Neural Re-ranking for Diversified Exercise Recommendation · SIGIR 2025
Mathematical optimization
continuous optimization
0.912025
De-singularity Subgradient for the q-th-Powered lₚ-Norm Weber Location Problem · AAAI 2025
Logic in computer science › knowledge representation and reasoning › knowledge representation
GOLOG
0.912025
A Syntactic Approach to Computing Complete and Sound Abstraction in the Situation Calculus · AAAI 2025
Automated reasoning and model checking
reasoning about actions
0.912025
A Syntactic Approach to Computing Complete and Sound Abstraction in the Situation Calculus · AAAI 2025
Computational finance and economics › portfolio management
portfolio optimization
0.822020
Loss Control with Rank-one Covariance Estimate for Short-term Portfolio Optimization · J. Mach. Learn. Res. 2020
Short-term Sparse Portfolio Optimization Based on Alternating Direction Method of Multipliers · J. Mach. Learn. Res. 2018
Computer vision › Vision and language › vision-language model › multimodal large language model
multimodal large language model reasoning
0.812024
Reason-and-Execute Prompting: Enhancing Multi-Modal Large Language Models for Solving Geometry Questions · ACM Multimedia 2024
Computer vision › Vision and language
visual question answering
0.812024
Reason-and-Execute Prompting: Enhancing Multi-Modal Large Language Models for Solving Geometry Questions · ACM Multimedia 2024
Logic in computer science
belief revision
0.812024
On the Logic of Theory Change Iteration of KM-Update, Revised · IJCAI 2024
Algorithms and data structures › decision diagrams
multivalued decision diagrams
0.812024
A Multi-Valued Decision Diagram-Based Approach to Constrained Optimal Path Problems over Directed Acyclic Graphs · IJCAI 2024
Knowledge, reasoning and agents › Planning, search and constraint satisfaction
epistemic planning
0.622019
Disjunctive Normal Form for Multi-Agent Modal Logics Based on Logical Separability · AAAI 2019
A Complete Epistemic Planner without the Epistemic Closed World Assumption · IJCAI 2015
Computational science and engineering
covariance estimation
0.412020
Loss Control with Rank-one Covariance Estimate for Short-term Portfolio Optimization · J. Mach. Learn. Res. 2020
Algorithmic game theory and mechanism design
combinatorial game theory
0.412020
Automatic Synthesis of Generalized Winning Strategies of Impartial Combinatorial Games Using SMT Solvers · IJCAI 2020
Logic in computer science
epistemic logic
0.422015
A Complete Epistemic Planner without the Epistemic Closed World Assumption · IJCAI 2015
On the Progression of Knowledge and Belief for Nondeterministic Actions in the Situation Calculus · IJCAI 2015
Algorithmic game theory and mechanism design › zero-sum game
impartial games
0.412020
Automatic Synthesis of Generalized Winning Strategies of Impartial Combinatorial Games Using SMT Solvers · IJCAI 2020

Methods — techniques the papers use, named apart from their topics

reinforcement learning · 2.9retrieval-augmented generation · 2.0contrastive learning · 2.0syntactic abstraction computation · 1.7sequence enhancement · 1.7refinement mapping · 1.7neural re-ranking · 1.7mLSTM · 1.7injection policy network · 1.0decoding-time intervention · 1.0GRPO · 1.0logical separability · 1.0q-th-powered l_p-norm · 0.9monte carlo tree search · 0.9de-singularity subgradient · 0.9subgradient method · 0.8reason-and-execute prompting · 0.8program-aided language prompting · 0.8
YearPublicationVenuePosition
2026 GraphRAG-Induced Dual Knowledge Structure Graphs for Personalized Learning Path Recommendation
abstract
Learning path recommendation seeks to provide students with a structured sequence of learning items (e.g., knowledge concepts or exercises) to optimize their learning efficiency. Despite significant efforts in this area, most existing methods primarily rely on prerequisite relations, which present two major limitations: (1) Prerequisite relations between knowledge concepts are difficult to obtain due to the cost of expert annotation, hindering the application of current learning path recommendation methods. (2) Relying on a single sequentially dependent knowledge structure based on prerequisite relations implies that a confusing knowledge concept can disrupt subsequent learning processes, which is referred to as blocked learning. To address these two challenges, we propose a novel approach, GraphRAG-Induced Dual Knowledge Structure Graphs for Personalized Learning Path Recommendation (KnowLP), which enhances learning path recommendations by incorporating both prerequisite and similarity relations between knowledge concepts. Specifically, we introduce a knowledge structure graph generation module EDU-GraphRAG that constructs knowledge structure graphs for different educational datasets, significantly improving the applicability of learning path recommendation methods. We then propose a Discrimination Learning-driven Reinforcement Learning (DLRL) module that utilizes similarity relations as fallback relations when prerequisite relations become ineffective, thereby alleviating the blocked learning. Finally, we conduct extensive experiments on three benchmark datasets, demonstrating that our method not only achieves state-of-the-art performance but also generates more effective and longer learning paths.
Xinghe Cheng, Jiapu Wang, Liangda Fang, Chaobo He, Quanlong Guan, Shirui Pan, Weiqi Luo 0002
AAAI4
2026 Mitigating Evidence Suppression: Bi-level Active Evidence Injection for Educational Video Understanding
abstract
Large Vision--Language Models (LVLMs) frequently fail on knowledge-intensive educational video QA despite the presence of requisite visual evidence. Through region-level analysis, we identify a systematic evidence-suppression pattern: task-critical tokens (e.g., diagrams) exhibit lower representational energy than distractors at the encoder output, rendering them prone to persistent attention neglect during decoding. While a controlled study shows that performance is sensitive to the strength and amount of injected candidate evidence signals, we find that rigid heuristics are insufficient due to sensitivity to token quality. To address this, we propose Bi-level Active Evidence Injection (BAEI), a decoding-time intervention that keeps the LVLM backbone frozen. BAEI employs a lightweight Injection Policy Network (IPN), optimized via GRPO, to dynamically select candidate evidence tokens and predict their token-wise injection strengths. The framework operates on two levels: increasing the contribution of candidate evidence-related signals in shallow layers and performing adaptive correction in deep layers triggered by predictive entropy. Experiments on educational benchmarks demonstrate consistent gains, validating decoding-time evidence intervention as an effective solution for factual alignment. The code is available at https://github.com/diojojolc-cell/BAEI.
Quanlong Guan, Chaobo He, Xingyu Zhu 0011, Liangda Fang
SIGIR6
2026 Dynamic comprehensive difficulty knowledge cells based on KAN network and stable learning for knowledge tracing
Qintai Hu, Qingpeng Wen, Bi Zeng, Liangda Fang
Neural Networks6
2025 A Syntactic Approach to Computing Complete and Sound Abstraction in the Situation Calculus
abstract
Abstraction is an important and useful concept in the field of artificial intelligence. To the best of our knowledge, there is no syntactic method to compute a sound and complete abstraction from a given low-level basic action theory and a refinement mapping. This paper aims to address this issue. To this end, we first present a variant of situation calculus, namely linear integer situation calculus, which serves as the formalization of high-level basic action theory. We then migrate Banihashemi, De Giacomo, and Lesperance’s abstraction framework to one from linear integer situation calculus to extended situation calculus. Furthermore, we identify a class of Golog programs, namely guarded actions, so as to restrict low-level Golog programs, and impose some restrictions on refinement mappings. Finally, we design a syntactic approach to computing a sound and complete abstraction from a low-level basic action theory and a restricted refinement mapping.
Liangda Fang, Kailun Luo, Zhenhe Cui, Quanlong Guan
AAAI1
2025 De-singularity Subgradient for the q-th-Powered lₚ-Norm Weber Location Problem
abstract
The Weber location problem is widely used in several artificial intelligence scenarios. However, the gradient of the objective does not exist at a considerable set of singular points. Recently, a de-singularity subgradient method has been proposed to fix this problem, but it can only handle the q-th-powered l_2-norm case (1
Zhao-Rong Lai, Liangda Fang, Ziliang Chen 0001, Cheng Li 0018
AAAI3
2025 PERC: A Prior-Guided Framework for Classifying Long-Content Educational Resources with Imbalanced Category Distributions
abstract
With the rapid growth of online education, the types and volumes of educational resources have increased significantly. Efficient classification of these resources can substantially reduce manual workload and enhance management effectiveness. However, existing models often struggle to accurately classify long-content educational content, particularly under imbalanced category distributions. To address these challenges, we propose PERC, a prior-guided framework for classifying long educational resources with imbalanced categories. To the best of our knowledge, PERC is the first framework to incorporate the foundational cognitive dimensions of Bloom's Taxonomy into educational resource classification. First, PERC leverages standardized pedagogical classification guidelines and maps the original label space into a semantically structured prior category space using a Structured State-Space Learning framework. Second, to handle the length and high information density of educational texts, we introduce a Dynamic Sliding Window Attention mechanism that captures both local and partial global dependencies, enabling the extraction of compact, semantically rich representations. Finally, a category-aware classifier integrates the prior representation of each category with the semantic representation of the resource to produce a category-aware embedding for final prediction. To evaluate PERC, we constructed two datasets: EduMix-24 and EduMath-24, comprising 18,799 educational resources manually annotated across 9 lesson types, 15 teaching modes, and 9 activity elements. Classification experiments on all three tasks consistently demonstrate that PERC outperforms state-of-the-art baselines.
Quanlong Guan, Xiuliang Duan, Xingyu Zhu 0011, Jianbo Huang, Zonglin Liu 0003, Liangda Fang
CIKM8
2025 KVFKT: A New Horizon in Knowledge Tracing with Attention-Based Embedding and Forgetting Curve Integration
abstract
The knowledge tracing (KT) model based on deep learning has been proven to be superior to the traditional knowledge tracing model, eliminating the need for artificial engineering features. However, there are still problems, such as insufficient interpretability of the learning and answering processes. To address these issues, we propose a new approach in knowledge tracing with attention-based embedding and forgetting curve integration, namely KVFKT. Firstly, the embedding representation module is responsible for embedding the questions and computing the attention vector of knowledge concepts (KCs) when students answer questions and when answer time stamps are collected. Secondly, the forgetting quantification module performs the pre-prediction update of the student’s knowledge state matrix. This quantification involves calculating the interval time and associated forgetting rate of relevant KCs, following the forgetting curve. Thirdly, the answer prediction module generates responses based on students’ knowledge status, guess coefficient, and question difficulty. Finally, the knowledge status update module further refines the students’ knowledge status according to their answers to the questions and the characteristics of those questions. In the experiment, four real-world datasets are used to test the model. Experimental results show that KVFKT better traces students’ knowledge state and outperforms state-of-the-art models.
Quanlong Guan, Xiuliang Duan, Kaiquan Bian, Guanliang Chen, Jianbo Huang, Zhiguo Gong, Liangda Fang
COLING7
2025 Language Models as Implicit Tree Search
abstract
Despite advancing language model (LM) alignment, direct preference optimization (DPO) falls short in LM reasoning with the free lunch from reinforcement learning (RL). As the breakthrough, this work proposes a new RL-free preference optimization method aiming to achieve DPO along with learning another LM, whose response generation policy holds the asymptotic equivalence with AlphaZero-like search, the apex of algorithms for complex reasoning missions like chess Go. While circumventing explicit value and reward modeling, the neural implicit tree search executed by the extra LM remains seeking to equip DPO with reasoning procedure technically akin to AlphaZero. Our experiments demonstrate that our methodology outperforms both regular DPO variants in human preference alignment, and MCTS-based LMs in mathematical reasoning and planning tasks.
Ziliang Chen 0001, Zhao-Rong Lai, Liangda Fang, Zhanfu Yang, Liang Lin 0004
ICML4
2025 Automatic Verification of Linear Integer Planning Programs via Forgetting in LIAUPF
Liangda Fang, Shikang Chen, Xiaoyou Lin, Chenyi Zhang 0001, Qingliang Chen, Quanlong Guan, Kaile Su
AAMAS1
2025 Improvements to the Generate-and-Complete Approach to Conformant Planning
abstract
Conformant planning is a computationally challenging task that generates an action sequence to achieve goal condition with uncertain initial states and non-deterministic actions. The generate-and-complete (in short, GC) approach shows superior performance on conformant planning, which iteratively enumerates the solution of a planning subproblem for a single initial state and attempts to extend it for all initial states until a conform solution is found. However, two major drawbacks of the GC approach hinder its performance: the computational overhead due to state exploration and the insertion of many redundant actions. To overcome the above drawbacks, we improve both verification and completion procedures. Experimental results show that the improved GC planner has significant improvements over the original GC approach in many instances with a large number of initial states. Our approach also outperforms all of state-of-the-art planners, solving 989 instances in comparison to 784, which is the most solved by DNF.
Liangda Fang, Min Zhan, Jin Tong, Xiujie Huang, Ziliang Chen 0001, Quanlong Guan
IJCAI1
2025 NR4DER: Neural Re-ranking for Diversified Exercise Recommendation
abstract
With the widespread adoption of online education platforms, an increasing number of students are gaining new knowledge through Massive Open Online Courses (MOOCs). Exercise recommendation have made strides toward improving student learning outcomes. However, existing methods not only struggle with high dropout rates but also fail to match the diverse learning pace of students. They frequently face difficulties in adjusting to inactive students' learning patterns and in accommodating individualized learning paces, resulting in limited accuracy and diversity in recommendations. To tackle these challenges, we propose Neural Re-ranking for Diversified Exercise Recommendation (in short, NR4DER). NR4DER first leverages the mLSTM model to improve the effectiveness of the exercise filter module. It then employs a sequence enhancement method to enhance the representation of inactive students, accurately matches students with exercises of appropriate difficulty. Finally, it utilizes neural re-ranking to generate diverse recommendation lists based on individual students' learning histories. Extensive experimental results indicate that NR4DER significantly outperforms existing methods across multiple real-world datasets and effectively caters to the diverse learning pace of students.
Xinghe Cheng, Xufang Zhou, Liangda Fang, Chaobo He, Yuyu Zhou, Weiqi Luo 0002, Zhiguo Gong, Quanlong Guan
SIGIR3
2025 Explainable exercise recommendation with knowledge graph
abstract
Recommending suitable exercises and providing the reasons for these recommendations is a highly valuable task, as it can significantly improve students' learning efficiency. Nevertheless, the extensive range of exercise resources and the diverse learning capacities of students present a notable difficulty in recommending exercises. Collaborative filtering approaches frequently have difficulties in recommending suitable exercises, whereas deep learning methods lack explanation, which restricts their practical use. To address these issue, this paper proposes KG4EER, an explainable exercise recommendation with a knowledge graph. KG4EER facilitates the matching of various students with suitable exercises and offers explanations for its recommendations. More precisely, a feature extraction module is introduced to represent students' learning features, and a knowledge graph is constructed to recommend exercises. This knowledge graph, which includes three primary entities - knowledge concepts, students, and exercises - and their interrelationships, serves to recommend suitable exercises. Extensive experiments conducted on three real-world datasets, coupled with expert interviews, establish the superiority of KG4EER over existing baseline methods and underscore its robust explainability.
Quanlong Guan, Xinghe Cheng, Fang Xiao, Zhuzhou Li, Chaobo He, Liangda Fang, Guanliang Chen, Zhiguo Gong, Weiqi Luo 0002
Neural Networks6
2024 Crowd Counting and Localization in Haze and Rain
abstract
Adverse weather conditions such as haze and fog often significantly reduce the performance of crowd counting models. An intuitive solution is to preprocess degraded images by applying image restoration techniques prior to crowd counting. However, this solution introduces additional computational complexity and may produce restored images with noise and artifacts that is harmful to the subsequent crowd counting task. To mitigate the two issues, we integrate an image restoration module (IRM) into a unified framework to propose an effective network for crowd counting and localization in haze and rain. The lightweight IRM is designed to guide the network to learn haze-aware knowledge in feature space, which is removed in the inference phase without increasing the computational cost. In addition, two new datasets are constructed to evaluate the crowd counting methods in haze and rain. Extensive experiments on both synthetic and real-world datasets demonstrate the superiority of the proposed method. The code is available at https://github.com/lizhangray/Dehaze-P2PNet.
Weijun Yuan, Liangda Fang, Zhixiang Qiu
ICME4
2024 On the Logic of Theory Change Iteration of KM-Update, Revised
Liangda Fang, Quanlong Guan, Junming Qiu, Zhao-Rong Lai, Weiqi Luo 0002, Hai Wan
IJCAI1
2024 A De-singularity Subgradient Approach for the Extended Weber Location Problem
Zhao-Rong Lai, Liangda Fang, Ziliang Chen 0001
IJCAI3
2024 A Multi-Valued Decision Diagram-Based Approach to Constrained Optimal Path Problems over Directed Acyclic Graphs
Mingwei Zhang 0007, Liangda Fang, Zhenhao Gu, Quanlong Guan, Yong Lai 0001
IJCAI2
2024 Exact Computation of Network Reliability with Sentential Decision Diagrams
abstract
Modern society largely depends on various network systems such as computer networks, communications, and power networks, it is crucial to exactly compute the reliability of these network systems. The exact computation of network reliability is known to be #P-Complete problem. The state-of-the-art exact computation method is based on binary decision diagrams (BDDs). Sentential decision diagrams (SDDs) are a new canonical representation of Boolean functions which is a strict superset of BDD. In both theoretical and practical perspectives, SDDs are a more compact representation than BDDs. In addition, it maintains canonicity and polynomial-time operations on Boolean functions. In this paper, we propose a top-down compilation algorithm based on SDD for representing the set of subgraphs that makes the network active. Then the exact computation of network reliability is based on the constructed SDD. The experiments show that in most real networks and all synthetic networks, the resulting SDD is smaller than the BDD representing the same set of subgraphs. Thus, SDD-based method to exact computation of network reliability is more efficient than BDD-based.
Delong Li, Jiayu Zeng, Liangda Fang, Chaonan Wang, Lin Cui 0001, Quanlong Guan
ISSRE3
2024 Reason-and-Execute Prompting: Enhancing Multi-Modal Large Language Models for Solving Geometry Questions
abstract
Multi-Modal Large Language Models (MM-LLMs) have demonstrated powerful reasoning abilities in various visual question-answering tasks. However, they face the challenge of lacking rigorous reasoning and precise arithmetic, when solving geometry questions. To address this challenge, we propose a novel prompting method, namely Reason-and-Execute (R&E), to enhance the accuracy of solving geometry questions by MM-LLMs. Specifically, the R&E method includes two templates: reasoning template and execution template. We first adopt a reverse-thinking approach to construct a rigorous reasoning template so that it guides MM-LLMs to start reasoning from the most relevant domain knowledge of the question and ultimately identify the arithmetic requirements. We then make use of program-assisted thought to construct execution template in order to guide MM-LLMs to understand the arithmetic requirements from reasoning template and generate executable code block. The answer is finally obtained by executing the code block. We evaluate our prompting method on 9 models in answering questions on 6 datasets (including four geometry datasets and two science datasets) compared to Chain-of-Thought (CoT) and Program-Aided Language (PAL) prompting methods. R&E method shows up to 12.8% improvement compared to CoT and PAL, proving strong reasoning and arithmetic abilities for solving geometry questions of our method. Moreover, we further analyze the answering accuracy from the different perspectives on solving geometric questions, including domain knowledge, geometry shapes, question length, and language. Through multiple analysis, our method is able to enhance the ability of MM-LLMs to solve geometry questions.
Xiuliang Duan, Dating Tan, Liangda Fang, Yuyu Zhou, Chaobo He, Ziliang Chen 0001, Lusheng Wu, Guanliang Chen, Zhiguo Gong, Weiqi Luo 0002, Quanlong Guan
ACM Multimedia3
2024 On the role of logical separability in knowledge compilation
Junming Qiu, Liangda Fang, Quanlong Guan, Zhanhao Xiao, Zhao-Rong Lai
Artif. Intell.3
2024 Multitrend Conditional Value at Risk for Portfolio Optimization
abstract
Trend representation has been attracting more and more attention recently in portfolio optimization (PO) via machine learning methods. It adopts concepts and phenomena from the field of empirical and behavioral finance when little prior knowledge is obtained or strict statistical assumptions cannot be guaranteed. It is used mostly in estimating the expected asset returns, but hardly in measuring risk. To fill this gap, we propose a novel multitrend conditional value at risk (MT-CVaR), which embeds multiple trends and their influences in CVaR. Besides, we propose a novel PO model with this MT-CVaR as the risk metric and then design a solving algorithm based on the interior point method to compute the portfolio. Extensive experiments on six benchmark datasets from diverse financial markets with different frequencies show that MT-CVaR achieves the state-of-the-art investing performance and risk management.
Zhao-Rong Lai, Cheng Li 0018, Quanlong Guan, Liangda Fang
IEEE Trans. Neural Networks Learn. Syst.5
2023 KG4Ex: An Explainable Knowledge Graph-Based Approach for Exercise Recommendation
abstract
Effective exercise recommendation is crucial for guiding students' learning trajectories and fostering their interest in the subject matter. However, the vast exercise resource and the varying learning abilities of individual students pose a significant challenge in selecting appropriate exercise questions. Collaborative filtering-based methods often struggle with recommending suitable exercises, while deep learning-based methods lack explanation, limiting their practical adoption. To address these limitations, this paper proposes KG4Ex, a knowledge graph-based exercise recommendation method. KG4Ex facilitates the matching of diverse students with suitable exercises while providing recommendation reasons. Specifically, we introduce a feature extraction module to represent students' learning states and construct a knowledge graph for exercise recommendation. This knowledge graph comprises three key entities (knowledge concepts, students, and exercises) and their interrelationships, and can be used to recommend suitable exercises. Extensive experiments on three real-world datasets and expert interviews demonstrate the superiority of KG4Ex over existing baseline methods and highlight its strong explainability.
Quanlong Guan, Fang Xiao, Xinghe Cheng, Liangda Fang, Ziliang Chen 0001, Guanliang Chen, Weiqi Luo 0002
CIKM4
2023 An Interpretable Model With Forgetting Matrix For Deep Knowledge Tracing
Quanlong Guan, Kaiquan Bian, Liangda Fang, Zhenyu He 0003, Lusheng Wu, Weiqi Luo 0002
CogSci3
2023 A Practical Framework of Blockchain in IoT Information Management
abstract
In order to improve the security of IoT information systems, this paper proposes the Blockchain-based Framework for Securing IoT Information (BFSII), which is built on consortium blockchain and the edge IoT architectures. This paper addresses data security in smart hotels as a research scenario. The majority of data generated by IoT devices in smart hotels contains users' private information, which is susceptible to alteration and leakage during transmission and storage. The BFSII solution leverages the decentralized nature of blockchain to enhance data traceability and tamper-proof capabilities. And it uses edge IoT architecture and consortium blockchain to improve system operational efficiency. Sensitive data generated by IoT devices are protected in BFSII. The experiment's findings show that BFSII can boost smart hotel system security while maintaining operational effectiveness. The information management system of smart hotels is provided with an inventive and secure solution by the BFSII framework.
Quanlong Guan, Jiawei Lei, Chaonan Wang, Guanggang Geng, Yuansheng Zhong, Liangda Fang, Xiujie Huang, Weiqi Luo 0002
SMC6
2023 NCDFSA: Neural Cognitive Diagnostic Focusing on Students' Attention to Knowledge Concepts
abstract
The primary aim of cognitive diagnosis is to predict students' performance and knowledge structures by analyzing their learning behavior and answering results, thereby enabling educators can provide personalized instruction. Scholars have proposed many cognitive diagnostic models. However, most of the models do not fully extract and utilize the relevant data and parameters of cognitive diagnosis. Moreover, some models only rely on artificially designed simple functions to analyze the cognitive process of students, which cannot fully capture the complex relationship between students and the exercises. To address these limitations, this paper proposes a neural cognitive diagnostic model named NCDFSA, which focuses on students' attention to knowledge concepts. The model utilizes neural networks to diagnose students' knowledge and considers students' implicit relationships with knowledge concepts. We introduce the concept of attention matrix(AM) and define the importance of knowledge concepts by the frequency of usage of knowledge concepts to improve the prediction effect. This paper compares NCDFSA with existing classical models on four real datasets and finds that the model has higher accuracy and rationality in predicting student performance.
Guoxiong Wei, Zhenyu He 0003, Quanlong Guan, Liangda Fang, Weiqi Luo 0002, Guanliang Chen
SMC4
2022 Knowledge Compilation Meets Logical Separability
Junming Qiu, Zhanhao Xiao, Quanlong Guan, Liangda Fang, Zhao-Rong Lai
AAAI5
2022 Knowledge Tracing Model with Learning and Forgetting Behavior
abstract
The Knowledge Tracing (KT) task aims to trace the changes of students' knowledge state in real time according to students' historical learning behavior, and predict students' future learning performance. The modern KT models have two problems. One is that these KT models can't reflect students' actual knowledge level. Most KT models only judge students' knowledge state based on their performance in exercises, and poor performance will lead to a decline in knowledge state. However, the essence of students' learning process is the process of acquiring knowledge, which is also a manifestation of learning behavior. Even if they answer the exercises incorrectly, they will still gain knowledge. The other problem is that many KT models don't pay enough attention to the impact of students' forgetting behavior on the knowledge state in the learning process. In fact, learning and forgetting behavior run through students' learning process, and their effects on students' knowledge state shouldn't be ignored. In this paper, based on educational psychology theory, we propose a knowledge tracing model with learning and forgetting behavior (LFBKT). LFBKT comprehensively considers the factors that affect learning and forgetting behavior to build the knowledge acquisition layer, knowledge absorption layer and knowledge forgetting layer. In addition, LFBKT introduces difficulty information to enrich the information of the exercise itself, while taking into account other answering performances besides the answer. Experimental results on two public datasets show that LFBKT can better trace students' knowledge state and outperforms existing models in terms of ACC and AUC.
Quanlong Guan, Zhenyu He 0003, Liangda Fang, Weiqi Luo 0002
CIKM5
2022 Cognitive Diagnosis Focusing on Knowledge Concepts
abstract
Cognitive diagnosis is a crucial task in the field of educational measurement and psychology, which aims to diagnose the strengths and weaknesses of participants. Existing cognitive diagnosis methods only consider which of knowledge concepts are involved in the knowledge components of exercises, but ignore the fact that different knowledge concepts have different effects on practice scores in actual learning situations. Therefore, researchers need to reshape the learning scene by combining the multi-factor relationships between knowledge components. In this paper, in order to more comprehensively simulate the interaction between students and exercises, we developed a neural network-based CDMFKC model for cognitive diagnosis. Our method not only captures the nonlinear interaction between exercise characteristics, student performance, and their mastery of each knowledge concept, but also further considers the impact of knowledge concepts by designing the difficulty and discrimination of knowledge concepts, and uses multiple neural layers to model their interaction so as to obtain accurate and interpretable diagnostic results. In addition, we propose an improved CDMFKC model with guessing parameter and slipping parameter designed by knowledge concept proficiency and student proficiency vectors. We validate the performance of these two diagnostic models on six real datasets. The experimental results show that the two models have better effects in the aspects of accuracy, rationality and interpretability.
Quanlong Guan, Liangda Fang, Fang Xiao, Zhenyu He 0003, Weiqi Luo 0002
CIKM3
2022 Molecular substructure graph attention network for molecular property identification in drug discovery
Xianbin Ye, Quanlong Guan, Weiqi Luo 0002, Liangda Fang, Zhao-Rong Lai, Jun Wang 0123
Pattern Recognit.4
2020 Dynamic Minimization of Bi-Kronecker Functional Decision Diagrams
Xuanxiang Huang, Haipeng Che, Liangda Fang, Qingliang Chen, Quanlong Guan, Yuhui Deng 0001, Kaile Su
ICCAD3
2020 Automatic Synthesis of Generalized Winning Strategies of Impartial Combinatorial Games Using SMT Solvers
abstract
Strategy representation and reasoning has recently received much attention in artificial intelligence. Impartial combinatorial games (ICGs) are a type of elementary and fundamental games in game theory. One of the challenging problems of ICGs is to construct winning strategies, particularly, generalized winning strategies for possibly infinitely many instances of ICGs. In this paper, we investigate synthesizing generalized winning strategies for ICGs. To this end, we first propose a logical framework to formalize ICGs based on the linear integer arithmetic fragment of numeric part of PDDL. We then propose an approach to generating the winning formula that exactly captures the states in which the player can force to win. Furthermore, we compute winning strategies for ICGs based on the winning formula. Experimental results on several games demonstrate the effectiveness of our approach.
Kaisheng Wu, Liangda Fang, Liping Xiong, Zhao-Rong Lai, Yong Qiao, Kaidong Chen, Fei Rong
IJCAI2
2020 Loss Control with Rank-one Covariance Estimate for Short-term Portfolio Optimization
abstract
In short-term portfolio optimization (SPO), some financial characteristics like the expected return and the true covariance might be dynamic. Then there are only a small window size $w$ of observations that are sufficiently close to the current moment and reliable to make estimations. $w$ is usually much smaller than the number of assets $d$, which leads to a typical undersampled problem. Worse still, the asset price relatives are not likely subject to any proper distributions. These facts violate the statistical assumptions of the traditional covariance estimates and invalidate their statistical efficiency and consistency in risk measurement. In this paper, we propose to reconsider the function of covariance estimates in the perspective of operators, and establish a rank-one covariance estimate in the principal rank-one tangent space at the observation matrix. Moreover, we propose a loss control scheme with this estimate, which effectively catches the instantaneous risk structure and avoids extreme losses. We conduct extensive experiments on $7$ real-world benchmark daily or monthly data sets with stocks, funds and portfolios from diverse regional markets to show that the proposed method achieves state-of-the-art performance in comprehensive downside risk metrics and gains good investing incomes as well. It offers a novel perspective of rank-related approaches for undersampled estimations in SPO.
Zhao-Rong Lai, Liming Tan, Liangda Fang
J. Mach. Learn. Res.4
2020 Reweighted Price Relative Tracking System for Automatic Portfolio Optimization
abstract
In this paper, we propose a novel reweighted price relative tracking (RPRT) system for automatic portfolio optimization (APO). In the price prediction stage, it automatically assigns separate weights to the price relative predictions according to each asset's performance, and these weights will also be automatically updated. In the portfolio optimizing stage, a novel tracking system with a generalized increasing factor is proposed to maximize the future wealth of next period. Besides, an efficient algorithm is designed to solve the portfolio optimization objective, which is applicable to large-scale and time-limited situations. Extensive experiments on six benchmark datasets from real financial markets with diverse assets and different time spans are conducted. RPRT outperforms other state-of-the-art systems in cumulative wealth, mean excess return, annual percentage yield, and some typical risk metrics. Moreover, it can withstand considerable transaction costs and runs fast. It indicates that RPRT is an effective and efficient APO system.
Zhao-Rong Lai, Pei-Yi Yang, Liangda Fang
IEEE Trans. Syst. Man Cybern. Syst.3
2019 Disjunctive Normal Form for Multi-Agent Modal Logics Based on Logical Separability
abstract
Modal logics are primary formalisms for multi-agent systems but major reasoning tasks in such logics are intractable, which impedes applications of multi-agent modal logics such as automatic planning. One technique of tackling the intractability is to identify a fragment called a normal form of multiagent logics such that it is expressive but tractable for reasoning tasks such as entailment checking, bounded conjunction transformation and forgetting. For instance, DNF of propositional logic is tractable for these reasoning tasks. In this paper, we first introduce a notion of logical separability and then define a novel disjunctive normal form SDNF for the multiagent logic Kn, which overcomes some shortcomings of existing approaches. In particular, we show that every modal formula in Kn can be equivalently casted as a formula in SDNF, major reasoning tasks tractable in propositional DNF are also tractable in SDNF, and moreover, formulas in SDNF enjoy the property of logical separability. To demonstrate the usefulness of our approach, we apply SDNF in multi-agent epistemic planning. Finally, we extend these results to three more complex multi-agent logics Dn, K45n and KD45n.
Liangda Fang, Kewen Wang 0001, Zhe Wang 0001, Ximing Wen
AAAI1
2019 Bi-Kronecker Functional Decision Diagrams: A Novel Canonical Representation of Boolean Functions
Xuanxiang Huang, Kehang Fang, Liangda Fang, Qingliang Chen, Zhao-Rong Lai, Linfeng Wei
AAAI3
2019 Tagged Sentential Decision Diagrams: Combining Standard and Zero-suppressed Compression and Trimming Rules
abstract
The Sentential Decision Diagram (SDD) is a compact and canonical representation of Boolean functions that generalizes the Ordered Binary Decision Diagrams (OBDDs). A variant of SDDs, namely Zero-suppressed Sentential Decision Diagrams (ZSDDs), was proposed recently by using different trimming rules. SDDs are suitable for functions where adjacent input assignments have the same outcome, while ZSDDs are more compact for spare functions. In this paper, we introduce a novel canonical SDD variant, called the Tagged Sentential Decision Diagrams (TSDDs). The key insight of TSDDs is to combine both trimming rules of SDDs and ZSDDs. With both characteristics of SDDs and ZSDDs, the TSDD representation is at least as small as the SDD or ZSDD representation for any Boolean functions. This is also shown in our experimental evaluation.
Liangda Fang, Biqing Fang, Hai Wan, Zeqi Zheng, Liang Chang 0003
ICCAD1
2019 Forgetting in multi-agent modal logics
Liangda Fang, Yongmei Liu 0001, Hans van Ditmarsch
Artif. Intell.1
2018 Dependence in Propositional Logic: Formula-Formula Dependence and Formula Forgetting - Application to Belief Update and Conservative Extension
Liangda Fang, Hai Wan, Xianqiao Liu, Biqing Fang, Zhao-Rong Lai
AAAI1
2018 Knowledge Compilation in the Multi-Agent Epistemic Logic Kn
Liangda Fang, Kewen Wang 0001, Zhe Wang 0001, Ximing Wen
KR1
2018 A kernel-based trend pattern tracking system for portfolio optimization
Zhao-Rong Lai, Pei-Yi Yang, Liangda Fang
Data Min. Knowl. Discov.4
2018 Short-term Sparse Portfolio Optimization Based on Alternating Direction Method of Multipliers
abstract
We propose a short-term sparse portfolio optimization (SSPO) system based on alternating direction method of multipliers (ADMM). Although some existing strategies have also exploited sparsity, they either constrain the quantity of the portfolio change or aim at the long-term portfolio optimization. Very few of them are dedicated to constructing sparse portfolios for the short-term portfolio optimization, which will be complemented by the proposed SSPO. SSPO concentrates wealth on a small proportion of assets that have good increasing potential according to some empirical financial principles, so as to maximize the cumulative wealth for the whole investment. We also propose a solving algorithm based on ADMM to handle the $\ell^1$-regularization term and the self-financing constraint simultaneously. As a significant improvement in the proposed ADMM, we have proven that its augmented Lagrangian has a saddle point, which is the foundation of the iterative formulae of ADMM but is seldom addressed by other sparsity strategies. Extensive experiments on $5$ benchmark data sets from real-world stock markets show that SSPO outperforms other state-of-the-art systems in thorough evaluations, withstands reasonable transaction costs and runs fast. Thus it is suitable for real-world financial environments.
Zhao-Rong Lai, Pei-Yi Yang, Liangda Fang
J. Mach. Learn. Res.3
2018 Trend representation based log-density regularization system for portfolio optimization
Pei-Yi Yang, Zhao-Rong Lai, Liangda Fang
Pattern Recognit.4
2016 Forgetting in Multi-Agent Modal Logics
Liangda Fang, Yongmei Liu 0001, Hans van Ditmarsch
IJCAI1
2015 On the Progression of Knowledge and Belief for Nondeterministic Actions in the Situation Calculus
Liangda Fang, Yongmei Liu 0001, Ximing Wen
IJCAI1
2015 A Complete Epistemic Planner without the Epistemic Closed World Assumption
Hai Wan, Liangda Fang, Yongmei Liu 0001, Huada Xu
IJCAI3
2013 Multiagent Knowledge and Belief Change in the Situation Calculus
abstract
Belief change is an important research topic in AI. It becomes more perplexing in multi-agent settings, since the action of an agent may be partially observable to other agents. In this paper, we present a general approach to reasoning about actions and belief change in multi-agent settings. Our approach is based on a multi-agent extension to the situation calculus, augmented by a plausibility relation over situations and another one over actions, which is used to represent agents' different perspectives on actions. When an action is performed, we update the agents' plausibility order on situations by giving priority to the plausibility order on actions, in line with the AGM approach of giving priority to new information. We show that our notion of belief satisfies KD45 properties. As to the special case of belief change of a single agent, we show that our framework satisfies most of the classical AGM, KM, and DP postulates. We also present properties concerning the change of common knowledge and belief of a group of agents.
Liangda Fang, Yongmei Liu 0001
AAAI1
2013 High-Level Program Execution in Multi-agent Settings
Liangda Fang
IJCAI1