Shicheng Liu

dblp:231/6618 · DBLP profile ↗
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13ranked-venue papers
6as first author
13since 2021 · last 2026
—ORCID · conflict

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

Artificial intelligence and machine learning · 8 · 6 first-author · 8 since 2021Software engineering, systems software and programming languages · 4 · 4 since 2021Applied, interdisciplinary, general and emerging computing · 1 · 1 since 2021
YearPublicationVenuePosition
2026 Keeper: Automated Testing and Fixing of Machine Learning Software - RCR Report
abstract
This artifact aims to provide source code, benchmark suite, results, and materials used in our study “Keeper: Automated Testing and Fixing of Machine Learning Software” [ 3 ]. We developed an automated testing and fixing tool Keeper and its IDE plugin for ML software. It automatically detects software defects and attempts to change how ML APIs are used to alleviate software misbehavior. This artifact provides guidelines to set up and execute Keeper and also guidelines to interpret our evaluation results. We hope this artifact can motivate and help future research to further tackle ML API misuses. All related data are available online.
Chengcheng Wan 0001, Shicheng Liu, Sophie Xie, Yuhan Liu 0004, Michael Maire, Henry Hoffmann, Shan Lu 0001
ACM Trans. Softw. Eng. Methodol.2
2025 Controllable and Reliable Knowledge-Intensive Task-Oriented Conversational Agents with Declarative Genie Worksheets
abstract
Large Language Models can carry out humanlike conversations in diverse settings, responding to user requests for tasks and knowledge.However, existing conversational agents implemented with LLMs often struggle with hallucination, following instructions with conditional logic, and integrating knowledge from different sources.These shortcomings compromise the agents' effectiveness, rendering them unsuitable for deployment.To address these challenges, we introduce Genie, a programmable framework for creating knowledge-intensive task-oriented conversational agents.Genie can handle involved interactions and answer complex queries.Unlike LLMs, it delivers reliable, grounded responses through advanced dialogue state management and supports controllable agent policies via its declarative specification -Genie Worksheet.This is achieved through an algorithmic runtime system that implements the developersupplied policy, limiting LLMs to ( 1) parse user input using a succinct conversational history, and (2) generate responses according to supplied context.Agents built with Genie outperform SOTA methods on complex logic dialogue datasets.We conducted a user study with 62 participants on three real-life applications: restaurant reservations with Yelp, as well as ticket submission and course enrollment for university students.Genie agents with GPT-4 Turbo outperformed the GPT-4 Turbo agents with function calling, improving goal completion rates from 21.8% to 82.8% across three real-world tasks.
Harshit Joshi, Shicheng Liu, Larsen Weigle, Monica S. Lam
ACL (1)2
2025 UTILITY: Utilizing Explainable Reinforcement Learning to Improve Reinforcement Learning
abstract
Reinforcement learning (RL) faces two challenges: (1) The RL agent lacks explainability. (2) The trained RL agent is, in many cases, non-optimal and even far from optimal. To address the first challenge, explainable reinforcement learning (XRL) is proposed to explain the decision-making of the RL agent. In this paper, we demonstrate that XRL can also be used to address the second challenge, i.e., improve RL performance. Our method has two parts. The first part provides a two-level explanation for why the RL agent is not optimal by identifying the mistakes made by the RL agent. Since this explanation includes the mistakes of the RL agent, it has the potential to help correct the mistakes and thus improve RL performance. The second part formulates a constrained bi-level optimization problem to learn how to best utilize the two-level explanation to improve RL performance. In specific, the upper level learns how to use the high-level explanation to shape the reward so that the corresponding policy can maximize the cumulative ground truth reward, and the lower level learns the corresponding policy by solving a constrained RL problem formulated using the low-level explanation. We propose a novel algorithm to solve this constrained bi-level optimization problem, and theoretically guarantee that the algorithm attains global optimality. We use MuJoCo experiments to show that our method outperforms state-of-the-art baselines.
Shicheng Liu
ICLR1
2025 Explainable Reinforcement Learning from Human Feedback to Improve Alignment
abstract
A common and effective strategy for humans to improve an unsatisfactory outcome in daily life is to find a cause of this outcome and correct the cause. In this paper, we investigate whether this human improvement strategy can be applied to improving reinforcement learning from human feedback (RLHF) for alignment of language models (LMs). In particular, it is observed in the literature that LMs tuned by RLHF can still output unsatisfactory responses. This paper proposes a method to improve the unsatisfactory responses by correcting their causes. Our method has two parts. The first part proposes a post-hoc explanation method to explain why an unsatisfactory response is generated to a prompt by identifying the training data that lead to this response. We formulate this problem as a constrained combinatorial optimization problem where the objective is to find a set of training data closest to this prompt-response pair in a feature representation space, and the constraint is that the prompt-response pair can be decomposed as a convex combination of this set of training data in the feature space. We propose an efficient iterative data selection algorithm to solve this problem. The second part proposes an unlearning method that improves unsatisfactory responses to some prompts by unlearning the training data that lead to these unsatisfactory responses and, meanwhile, does not significantly degrade satisfactory responses to other prompts. Experimental results demonstrate that our algorithm can improve RLHF.
Shicheng Liu, Wenjie Qiu 0002, Hangfan Zhang
NeurIPS1
2024 Meta Inverse Constrained Reinforcement Learning: Convergence Guarantee and Generalization Analysis
abstract
This paper considers the problem of learning the reward function and constraints of an expert from few demonstrations. This problem can be considered as a meta-learning problem where we first learn meta-priors over reward functions and constraints from other distinct but related tasks and then adapt the learned meta-priors to new tasks from only few expert demonstrations. We formulate a bi-level optimization problem where the upper level aims to learn a meta-prior over reward functions and the lower level is to learn a meta-prior over constraints. We propose a novel algorithm to solve this problem and formally guarantee that the algorithm reaches the set of $\epsilon$-stationary points at the iteration complexity $O(\frac{1}{\epsilon^2})$. We also quantify the generalization error to an arbitrary new task. Experiments are used to validate that the learned meta-priors can adapt to new tasks with good performance from only few demonstrations.
Shicheng Liu
ICLR1
2024 In-Trajectory Inverse Reinforcement Learning: Learn Incrementally Before an Ongoing Trajectory Terminates
abstract
Inverse reinforcement learning (IRL) aims to learn a reward function and a corresponding policy that best fit the demonstrated trajectories of an expert. However, current IRL works cannot learn incrementally from an ongoing trajectory because they have to wait to collect at least one complete trajectory to learn. To bridge the gap, this paper considers the problem of learning a reward function and a corresponding policy while observing the initial state-action pair of an ongoing trajectory and keeping updating the learned reward and policy when new state-action pairs of the ongoing trajectory are observed. We formulate this problem as an online bi-level optimization problem where the upper level dynamically adjusts the learned reward according to the newly observed state-action pairs with the help of a meta-regularization term, and the lower level learns the corresponding policy. We propose a novel algorithm to solve this problem and guarantee that the algorithm achieves sub-linear local regret $O(\sqrt{T}+\log T+\sqrt{T}\log T)$. If the reward function is linear, we prove that the proposed algorithm achieves sub-linear regret $O(\log T)$. Experiments are used to validate the proposed algorithm.
Shicheng Liu
NeurIPS1
2024 Keeper: Automated Testing and Fixing of Machine Learning Software
abstract
The increasing number of software applications incorporating machine learning (ML) solutions has led to the need for testing techniques. However, testing ML software requires tremendous human effort to design realistic and relevant test inputs and to judge software output correctness according to human common sense. Even when misbehavior is exposed, it is often unclear whether the defect is inside ML API or the surrounding code and how to fix the implementation. This article tackles these challenges by proposing Keeper, an automated testing and fixing tool for ML software. The core idea of Keeper is designing pseudo-inverse functions that semantically reverse the corresponding ML task in an empirical way and proxy common human judgment of real-world data. It incorporates these functions into a symbolic execution engine to generate tests. Keeper also detects code smells that degrade software performance. Once misbehavior is exposed, Keeper attempts to change how ML APIs are used to alleviate the misbehavior. Our evaluation on a variety of applications shows that Keeper greatly improves branch coverage, while identifying 74 previously unknown failures and 19 code smells from 56 out of 104 applications. Our user studies show that 78% of end-users and 95% of developers agree with Keeper’s detection and fixing results.
Chengcheng Wan 0001, Shicheng Liu, Sophie Xie, Yuhan Liu 0004, Henry Hoffmann, Michael Maire, Shan Lu 0001
ACM Trans. Softw. Eng. Methodol.2
2023 Fine-tuned LLMs Know More, Hallucinate Less with Few-Shot Sequence-to-Sequence Semantic Parsing over Wikidata
abstract
While large language models (LLMs) can answer many questions correctly, they can also hallucinate and give wrong answers.Wikidata, with its over 12 billion facts, can be used to ground LLMs to improve their factuality.This paper presents WikiWebQuestions, a highquality question answering benchmark for Wikidata.Ported over from WebQuestions for Freebase, it consists of real-world data with SPARQL annotation.This paper presents a few-shot sequence-tosequence semantic parser for Wikidata.We modify SPARQL to use the unique domain and property names instead of their IDs.We train the parser to use either the results from an entity linker or mentions in the query.We fine-tune LLaMA by adding the few-shot training data to that used to fine-tune Alpaca.Our experimental results demonstrate the effectiveness of this methodology, establishing a strong baseline of 76% and 65% answer accuracy in the dev and test sets of WikiWeb-Questions, respectively.By pairing our semantic parser with GPT-3, we combine verifiable results with qualified GPT-3 guesses to provide useful answers to 96% of the questions in dev.We also show that our method outperforms the state-of-the-art for the QALD-7 Wikidata dataset by 3.6% in F1 score. 1 * Equal contribution 1 Code, data, and model are available at https://github.com/stanford-oval/ wikidata-emnlp23
Silei Xu, Shicheng Liu, Theo Culhane, Elizaveta Pertseva, Meng-Hsi Wu, Sina J. Semnani, Monica S. Lam
EMNLP2
2023 Learning Multi-agent Behaviors from Distributed and Streaming Demonstrations
abstract
This paper considers the problem of inferring the behaviors of multiple interacting experts by estimating their reward functions and constraints where the distributed demonstrated trajectories are sequentially revealed to a group of learners. We formulate the problem as a distributed online bi-level optimization problem where the outer-level problem is to estimate the reward functions and the inner-level problem is to learn the constraints and corresponding policies. We propose a novel ``multi-agent behavior inference from distributed and streaming demonstrations" (MA-BIRDS) algorithm that allows the learners to solve the outer-level and inner-level problems in a single loop through intermittent communications. We formally guarantee that the distributed learners achieve consensus on reward functions, constraints, and policies, the average local regret (over $N$ online iterations) decreases at the rate of $O(1/N^{1-\eta_1}+1/N^{1-\eta_2}+1/N)$, and the cumulative constraint violation increases sub-linearly at the rate of $O(N^{\eta_2}+1)$ where $\eta_1,\eta_2\in (1/2,1)$.
Shicheng Liu
NeurIPS1
2022 Automated Testing of Software that Uses Machine Learning APIs
abstract
An increasing number of software applications incorporate machine learning (ML) solutions for cognitive tasks that statistically mimic human behaviors. To test such software, tremendous human effort is needed to design image/text/audio inputs that are relevant to the software, and to judge whether the software is processing these inputs as most human beings do. Even when misbehavior is exposed, it is often unclear whether the culprit is inside the cognitive ML API or the code using the API.
Chengcheng Wan 0001, Shicheng Liu, Sophie Xie, Henry Hoffmann, Michael Maire, Shan Lu 0001
ICSE2
2022 Distributed Inverse Constrained Reinforcement Learning for Multi-agent Systems
abstract
This paper considers the problem of recovering the policies of multiple interacting experts by estimating their reward functions and constraints where the demonstration data of the experts is distributed to a group of learners. We formulate this problem as a distributed bi-level optimization problem and propose a novel bi-level ``distributed inverse constrained reinforcement learning" (D-ICRL) algorithm that allows the learners to collaboratively estimate the constraints in the outer loop and learn the corresponding policies and reward functions in the inner loop from the distributed demonstrations through intermittent communications. We formally guarantee that the distributed learners asymptotically achieve consensus which belongs to the set of stationary points of the bi-level optimization problem.
Shicheng Liu
NeurIPS1
2022 Detecting clusters of transcription factors based on a nonhomogeneous poisson process model
abstract
BACKGROUND: Rapidly growing genome-wide ChIP-seq data have provided unprecedented opportunities to explore transcription factor (TF) binding under various cellular conditions. Despite the rich resources, development of analytical methods for studying the interaction among TFs in gene regulation still lags behind. RESULTS: In order to address cooperative TF binding and detect TF clusters with coordinative functions, we have developed novel computational methods based on clustering the sample paths of nonhomogeneous Poisson processes. Simulation studies demonstrated the capability of these methods to accurately detect TF clusters and uncover the hierarchy of TF interactions. A further application to the multiple-TF ChIP-seq data in mouse embryonic stem cells (ESCs) showed that our methods identified the cluster of core ESC regulators reported in the literature and provided new insights on functional implications of transcrisptional regulatory modules. CONCLUSIONS: Effective analytical tools are essential for studying protein-DNA relations. Information derived from this research will help us better understand the orchestration of transcription factors in gene regulation processes.
Shicheng Liu, Guanying Liang
BMC Bioinform.2
2021 Are Machine Learning Cloud APIs Used Correctly?
abstract
Machine learning (ML) cloud APIs enable developers to easily incorporate learning solutions into software systems. Unfortunately, ML APIs are challenging to use correctly and efficiently, given their unique semantics, data requirements, and accuracy-performance tradeoffs. Much prior work has studied how to develop ML APIs or ML cloud services, but not how open-source applications are using ML APIs. In this paper, we manually studied 360 representative open-source applications that use Google or AWS cloud-based ML APIs, and found 70% of these applications contain API misuses in their latest versions that degrade functional, performance, or economical quality of the software. We have generalized 8 anti-patterns based on our manual study and developed automated checkers that identify hundreds of more applications that contain ML API misuses.
Chengcheng Wan 0001, Shicheng Liu, Henry Hoffmann, Michael Maire, Shan Lu 0001
ICSE2