VLDB 2026 Research / reviewers in the wild / expert
Gopi Krishnan Rajbahadur
dblp:202/1487
· DBLP profile ↗
20ranked-venue papers
5as first author
16since 2021 · last 2027
0000-0003-1812-5365ORCID · verified
Domains — the database's venue-derived domains; a paper can count in several
Software engineering, systems software and programming languages · 18 · 4 first-author · 15 since 2021Artificial intelligence and machine learning · 2 · 1 first-author · 1 since 2021Databases, data management, data science and information retrieval · 2 · 1 first-author · 1 since 2021
| Year | Publication | Venue | Position |
|---|---|---|---|
| 2027 | Less is more: balancing models performance and complexity for software defects prediction
Moataz Chouchen, Ali Ouni 0001, Gopi Krishnan Rajbahadur, Ahmed E. Hassan |
Empir. Softw. Eng. | 3 |
| 2026 | An empirical study of testing practices in open source AI agent frameworks and agentic applications
Mohammed Mehedi Hasan, Hao Li 0094, Emad Fallahzadeh, Gopi Krishnan Rajbahadur, Bram Adams, Ahmed E. Hassan |
Empir. Softw. Eng. | 4 |
| 2025 | SPICE: An Automated SWE-Bench Labeling Pipeline for Issue Clarity, Test Coverage, and Effort EstimationabstractHigh-quality labeled datasets are crucial for training and evaluating foundation models in software engineering, but creating them is often prohibitively expensive and labor-intensive. We introduce SPICE, a scalable, automated pipeline for labeling SWE-bench-style datasets with annotations for issue clarity, test coverage, and effort estimation. SPICE combines context-aware code navigation, rationale-driven prompting, and multi-pass consensus to produce labels that closely approximate expert annotations. SPICE’s design was informed by our own experience and frustration in labeling more than 800 instances from SWE-Gym. SPICE achieves strong agreement with human-labeled SWE-bench Verified data while reducing the cost of labeling 1,000 instances from around $100,000 (manual annotation) to only $5.10. These results demonstrate SPICE’s potential to enable cost-effective, large-scale dataset creation for SE-focused FMs. To support the community, we release both SPICE tool and SPICE Bench, a new dataset of 6,802 SPICE-labeled instances curated from 291 open-source projects in SWE-Gym (over 13x larger than SWE-bench Verified). Gustavo Ansaldi Oliva, Gopi Krishnan Rajbahadur, Aaditya Bhatia, Haoxiang Zhang 0001, Zhilong Chen, Arthur Leung, Dayi Lin, Boyuan Chen 0002, Ahmed E. Hassan |
ASE | 2 |
| 2025 | The Hitchhikers Guide to Production-ready Trustworthy Foundation Model Powered Software (FMware)abstractFoundation Models (FMs) such as Large Language Models (LLMs) are reshaping the software industry by enabling FMware, systems that integrate these FMs as core components.In this KDD 2025 tutorial, we present a comprehensive exploration of FMware that combines a curated catalogue of challenges with real-world production concerns.We first discuss the state of research and practice in building FMware.We further examine the difficulties in selecting suitable models, aligning high-quality domain-specific data, engineering robust prompts, and orchestrating autonomous agents.We then address the complex journey from impressive demos to production-ready systems by outlining issues in system testing, optimization, deployment, and integration with legacy software.Drawing on our industrial experience and recent research in the area, we provide actionable insights and a technology roadmap for overcoming these challenges.Attendees will gain practical strategies to enable the creation of trustworthy FMware in the evolving technology landscape. Kirill Vasilevski, Gopi Krishnan Rajbahadur, Gustavo Ansaldi Oliva, Benjamin Rombaut 0002, Keheliya Gallaba, Filipe Roseiro Côgo, Jiahuei Lin, Dayi Lin, Haoxiang Zhang 0001, Bouyan Chen, Kishanthan Thangarajah, Ahmed E. Hassan, Zhen Ming (Jack) Jiang |
KDD (2) | 2 |
| 2025 | Prompt Me: Intelligent Software Agent for Requirements Engineering - A Vision Paper
Jacek Dabrowski 0001, Amel Bennaceur, Gopi Krishnan Rajbahadur, Bashar Nuseibeh, Faeq Alrimawi |
REFSQ | 3 |
| 2025 | Studying the Impact of TensorFlow and PyTorch Bindings on Machine Learning Software QualityabstractBindings for machine learning frameworks (such as TensorFlow and PyTorch) allow developers to integrate a framework’s functionality using a programming language different from the framework’s default language (usually Python). In this article, we study the impact of using TensorFlow and PyTorch bindings in C#, Rust, Python and JavaScript on the software quality in terms of correctness (training and test accuracy) and time cost (training and inference time) when training and performing inference on five widely used deep learning models. Our experiments show that a model can be trained in one binding and used for inference in another binding for the same framework without losing accuracy. Our study is the first to show that using a non-default binding can help improve machine learning software quality from the time cost perspective compared to the default Python binding while still achieving the same level of correctness. Hao Li 0094, Gopi Krishnan Rajbahadur, Cor-Paul Bezemer |
ACM Trans. Softw. Eng. Methodol. | 2 |
| 2025 | SimClone: Detecting Tabular Data Clones Using Value SimilarityabstractData clones are defined as multiple copies of the same data among datasets. The presence of data clones between datasets can cause issues such as difficulties in managing data assets and data license violations when using datasets with clones to build AI software. However, detecting data clones is not trivial. The majority of the prior studies in this area rely on structural information to detect data clones (e.g., font size, column header). However, tabular datasets used to build AI software are typically stored without any structural information. In this article, we propose a novel method called SimClone for data clone detection in tabular datasets without relying on structural information. SimClone method utilizes value similarities for data clone detection. We also propose a visualization approach as a part of our SimClone method to help locate the exact position of the cloned data between a dataset pair. Our results show that our SimClone outperforms the current state-of-the-art method by at least 20% in terms of both F1-score and AUC. In addition, SimClone’s visualization component helps identify the exact location of the data clone in a dataset with a Precision@10 value of 0.80 in the top 20 true positive predictions. Gopi Krishnan Rajbahadur, Dayi Lin, Shaowei Wang 0002, Zhen Ming (Jack) Jiang |
ACM Trans. Softw. Eng. Methodol. | 2 |
| 2023 | Towards Privacy Preserving Cross Project Defect Prediction with Federated LearningabstractDefect prediction models can predict defects in software projects, and many researchers study defect prediction models to assist debugging efforts in software development. In recent years, there has been growing interest in Cross Project Defect Prediction (CPDP), which predicts defects in a project using a defect prediction model learned from other projects’ data when there is insufficient data to construct a defect prediction model. Since CPDP uses other projects’ data, data privacy preservation is one of the most significant issues. However, prior CPDP studies still require data sharing among projects to train models, and do not fully consider protecting project confidentiality. To address this, we propose a CPDP model FLR employing federated learning, a distributed machine learning approach that does not require data sharing. We evaluate FLR, using 25 projects, to investigate its effectiveness and feature interpretation. Our key results show that first, FLR outperforms the existing privacy-preserving methods (i.e., LACE2). Meanwhile, the performance is relatively comparable to the conventional methods (e.g., supervised and unsupervised learning). Second, the results of the interpretation analysis show that scale-related features have a common effect on the prediction performance of the FLR. In addition, further insights demonstrate that parameters of federated learning (e.g., learning rates and the number of clients) also play a role in the performance. This study is served as a first step to confirm the feasibility of the employment of federated learning in CPDP to ensure privacy preservation and lays the groundwork for future research on applying other machine learning models to federated learning. Hiroki Yamamoto, Dong Wang 0044, Gopi Krishnan Rajbahadur, Masanari Kondo, Yasutaka Kamei, Naoyasu Ubayashi |
SANER | 3 |
| 2023 | What makes Ethereum blockchain transactions be processed fast or slow? An empirical study
Michael Pacheco, Gustavo Ansaldi Oliva, Gopi Krishnan Rajbahadur, Ahmed E. Hassan |
Empir. Softw. Eng. | 3 |
| 2023 | Is My Transaction Done Yet? An Empirical Study of Transaction Processing Times in the Ethereum Blockchain PlatformabstractEthereum is one of the most popular platforms for the development of blockchain-powered applications. These applications are known as ÐApps. When engineering ÐApps, developers need to translate requests captured in the front-end of their application into one or more smart contract transactions. Developers need to pay for these transactions and, the more they pay (i.e., the higher the gas price), the faster the transaction is likely to be processed. Developing cost-effective ÐApps is far from trivial, as developers need to optimize the balance between cost (transaction fees) and user experience (transaction processing times). Online services have been developed to provide transaction issuers (e.g., ÐApp developers) with an estimate of how long transactions will take to be processed given a certain gas price. These estimation services are crucial in the Ethereum domain and several popular wallets such as Metamask rely on them. However, despite their key role, their accuracy has not been empirically investigated so far. In this article, we quantify the transaction processing times in Ethereum, investigate the relationship between processing times and gas prices, and determine the accuracy of state-of-the-practice estimation services. Our results indicate that transactions are processed in a median of 57 seconds and that 90% of the transactions are processed within 8 minutes. We also show that higher gas prices result in faster transaction processing times with diminishing returns. In particular, we observe no practical difference in processing time between expensive and very expensive transactions. With regards to the accuracy of processing time estimation services, we observe that they are equivalent. However, when stratifying transactions by gas prices, we observe that Etherscan’s Gas Tracker is the most accurate estimation service for the very cheap and cheap transactions. EthGasStation’s Gas Price API, in turn, is the most accurate estimation service for regular, expensive, and very expensive transactions. In a post-hoc study, we design a simple linear regression model with only one feature that outperforms the Gas Tracker for very cheap and cheap transactions and that performs as accurately as the EthGasStation model for the remaining categories. Based on our findings, ÐApp developers can make more informed decisions concerning the choice of the gas price of their application-issued transactions. Michael Pacheco, Gustavo Ansaldi Oliva, Gopi Krishnan Rajbahadur, Ahmed E. Hassan |
ACM Trans. Softw. Eng. Methodol. | 3 |
| 2022 | Towards Training Reproducible Deep Learning ModelsabstractReproducibility is an increasing concern in Artificial Intelligence (AI), particularly in the area of Deep Learning (DL). Being able to reproduce DL models is crucial for AI-based systems, as it is closely tied to various tasks like training, testing, debugging, and auditing. However, DL models are challenging to be reproduced due to issues like randomness in the software (e.g., DL algorithms) and non-determinism in the hardware (e.g., GPU). There are various practices to mitigate some of the aforementioned issues. However, many of them are either too intrusive or can only work for a specific usage context. In this paper, we propose a systematic approach to training reproducible DL models. Our approach includes three main parts: (1) a set of general criteria to thoroughly evaluate the reproducibility of DL models for two different domains, (2) a unified framework which leverages a record-and-replay technique to mitigate software-related randomness and a profile-and-patch technique to control hardware-related non-determinism, and (3) a reproducibility guideline which explains the rationales and the mitigation strategies on conducting a reproducible training process for DL models. Case study results show our approach can successfully reproduce six open source and one commercial DL models. Boyuan Chen 0002, Mingzhi Wen, Yong Shi 0010, Dayi Lin, Gopi Krishnan Rajbahadur, Zhen Ming (Jack) Jiang |
ICSE | 5 |
| 2022 | Revisiting reopened bugs in open source software systems
Ankur Tagra, Haoxiang Zhang 0001, Gopi Krishnan Rajbahadur, Ahmed E. Hassan |
Empir. Softw. Eng. | 3 |
| 2022 | Towards a Consistent Interpretation of AIOps ModelsabstractArtificial Intelligence for IT Operations (AIOps) has been adopted in organizations in various tasks, including interpreting models to identify indicators of service failures. To avoid misleading practitioners, AIOps model interpretations should be consistent (i.e., different AIOps models on the same task agree with one another on feature importance). However, many AIOps studies violate established practices in the machine learning community when deriving interpretations, such as interpreting models with suboptimal performance, though the impact of such violations on the interpretation consistency has not been studied. In this article, we investigate the consistency of AIOps model interpretation along three dimensions: internal consistency, external consistency, and time consistency. We conduct a case study on two AIOps tasks: predicting Google cluster job failures and Backblaze hard drive failures. We find that the randomness from learners, hyperparameter tuning, and data sampling should be controlled to generate consistent interpretations. AIOps models with AUCs greater than 0.75 yield more consistent interpretation compared to low-performing models. Finally, AIOps models that are constructed with the Sliding Window or Full History approaches have the most consistent interpretation with the trends presented in the entire datasets. Our study provides valuable guidelines for practitioners to derive consistent AIOps model interpretation. Yingzhe Lyu, Gopi Krishnan Rajbahadur, Dayi Lin, Boyuan Chen 0002, Zhen Ming (Jack) Jiang |
ACM Trans. Softw. Eng. Methodol. | 2 |
| 2022 | Revisiting the Impact of Dependency Network Metrics on Software Defect PredictionabstractSoftware dependency network metrics extracted from the dependency graph of the software modules by the application of Social Network Analysis (SNA metrics) have been shown to improve the performance of the Software Defect prediction (SDP) models. However, the relative effectiveness of these SNA metrics over code metrics in improving the performance of the SDP models has been widely debated with no clear consensus. Furthermore, some of the common SDP scenarios like predicting the number of defects in a module (Defect-count) in Cross-version and Cross-project SDP contexts remain unexplored. Such lack of clear directive on the effectiveness of SNA metrics when compared to the widely used code metrics prevents us from potentially building better performing SDP models. Therefore, through a case study of 9 open source software projects across 30 versions, we study the relative effectiveness of SNA metrics when compared to code metrics across 3 commonly used SDP contexts (Within-project, Cross-version and Cross-project) and scenarios (Defect-count, Defect-classification (classifying if a module is defective) and Effort-aware (ranking the defective modules w.r.t to the involved effort)). We find the SNA metrics by themselves or along with code metrics improve the performance of SDP models over just using code metrics on 5 out of the 9 studied SDP scenarios (three SDP scenarios across three SDP contexts). However, we note that in some cases the improvements afforded by considering SNA metrics over or alongside code metrics might only be marginal, whereas in other cases the improvements could be potentially large. Based on these findings we suggest that the future work should: consider SNA metrics alongside code metrics in their SDP models; as well as consider Ego metrics and Global metrics, the two different types of the SNA metrics separately when training SDP models as they behave differently. Lina Gong, Gopi Krishnan Rajbahadur, Ahmed E. Hassan, Shujuan Jiang |
IEEE Trans. Software Eng. | 2 |
| 2022 | The Impact of Feature Importance Methods on the Interpretation of Defect ClassifiersabstractClassifier specific (CS) and classifier agnostic (CA) feature importance methods are widely used (often interchangeably) by prior studies to derive feature importance ranks from a defect classifier. However, different feature importance methods are likely to compute different feature importance ranks even for the same dataset and classifier. Hence such interchangeable use of feature importance methods can lead to conclusion instabilities unless there is a strong agreement among different methods. Therefore, in this paper, we evaluate the agreement between the feature importance ranks associated with the studied classifiers through a case study of 18 software projects and six commonly used classifiers. We find that: 1) The computed feature importance ranks by CA and CS methods do not always strongly agree with each other. 2) The computed feature importance ranks by the studied CA methods exhibit a strong agreement including the features reported at top-1 and top-3 ranks for a given dataset and classifier, while even the commonly used CS methods yield vastly different feature importance ranks. Such findings raise concerns about the stability of conclusions across replicated studies. We further observe that the commonly used defect datasets are rife with feature interactions and these feature interactions impact the computed feature importance ranks of the CS methods (not the CA methods). We demonstrate that removing these feature interactions, even with simple methods like CFS improves agreement between the computed feature importance ranks of CA and CS methods. In light of our findings, we provide guidelines for stakeholders and practitioners when performing model interpretation and directions for future research, e.g., future research is needed to investigate the impact of advanced feature interaction removal methods on computed feature importance ranks of different CS methods. Gopi Krishnan Rajbahadur, Shaowei Wang 0002, Gustavo Ansaldi Oliva, Yasutaka Kamei, Ahmed E. Hassan |
IEEE Trans. Software Eng. | 1 |
| 2021 | Impact of Discretization Noise of the Dependent Variable on Machine Learning Classifiers in Software EngineeringabstractResearchers usually discretize a continuous dependent variable into two target classes by introducing an artificial discretization threshold (e.g., median). However, such discretization may introduce noise (i.e., discretization noise) due to ambiguous class loyalty of data points that are close to the artificial threshold. Previous studies do not provide a clear directive on the impact of discretization noise on the classifiers and how to handle such noise. In this paper, we propose a framework to help researchers and practitioners systematically estimate the impact of discretization noise on classifiers in terms of its impact on various performance measures and the interpretation of classifiers. Through a case study of 7 software engineering datasets, we find that: 1) discretization noise affects the different performance measures of a classifier differently for different datasets; 2) Though the interpretation of the classifiers are impacted by the discretization noise on the whole, the top 3 most important features are not affected by the discretization noise. Therefore, we suggest that practitioners and researchers use our framework to understand the impact of discretization noise on the performance of their built classifiers and estimate the exact amount of discretization noise to be discarded from the dataset to avoid the negative impact of such noise. Gopi Krishnan Rajbahadur, Shaowei Wang 0002, Yasutaka Kamei, Ahmed E. Hassan |
IEEE Trans. Software Eng. | 1 |
| 2020 | An empirical study of the characteristics of popular Minecraft mods
Gopi Krishnan Rajbahadur, Dayi Lin, Mohammed Sayagh, Cor-Paul Bezemer, Ahmed E. Hassan |
Empir. Softw. Eng. | 2 |
| 2019 | Pitfalls Analyzer: Quality Control for Model-Driven Data Science PipelinesabstractData science pipelines are a sequence of data processing steps that aim to derive knowledge and insights from raw data. Data science pipeline tools simplify the creation and automation of data science pipelines by providing reusable building blocks that users can drag and drop into their pipelines. Such a graphical, model-driven approach enables users with limited data science expertise to create complex pipelines. However, recent studies show that there exist several data science pitfalls that can yield spurious results and, consequently, misleading insights. Yet, none of the popular pipeline tools have built-in quality control measures to detect these pitfalls. Therefore, in this paper, we propose an approach called Pitfalls Analyzer to detect common pitfalls in data science pipelines. As a proof-of-concept, we implemented a prototype of the Pitfalls Analyzer for KNIME, which is one of the most popular data science pipeline tools. Our prototype is model-driven, since the detection of pitfalls is accomplished using pipelines that were created with KNIME building blocks. To showcase the effectiveness of our approach, we run our prototype on 11 pipelines that were created by KNIME experts for 3 Internet-of-Things (IoT) projects. The results indicate that our prototype flags all and only those instances of the pitfalls that we were able to flag while manually inspecting the pipelines. Gopi Krishnan Rajbahadur, Gustavo Ansaldi Oliva, Ahmed E. Hassan, Jürgen Dingel |
MoDELS | 1 |
| 2018 | A Survey of Anomaly Detection for Connected Vehicle Cybersecurity and SafetyabstractAnomaly detection techniques have been applied to the challenging problem of ensuring both cybersecurity and safety of connected vehicles. We propose a taxonomy of prior research in this domain. Our proposed taxonomy has 3 overarching dimensions subsuming 9 categories and 38 subcategories. Key observations emerging from the survey are: Real-world datasets are seldom used, but instead, most results are derived from simulations; V2V/V2I communications and in vehicle communication are not considered together; proposed techniques are seldom evaluated against a baseline; safety of the vehicles does not attract as much attention as cybersecurity. Gopi Krishnan Rajbahadur, Andrew J. Malton, Andrew Walenstein, Ahmed E. Hassan |
Intelligent Vehicles Symposium | 1 |
| 2017 | The impact of using regression models to build defect classifiersabstractIt is common practice to discretize continuous defect counts into defective and non-defective classes and use them as a target variable when building defect classifiers (discretized classifiers). However, this discretization of continuous defect counts leads to information loss that might affect the performance and interpretation of defect classifiers. Another possible approach to build defect classifiers is through the use of regression models then discretizing the predicted defect counts into defective and non-defective classes (regression-based classifiers). In this paper, we compare the performance and interpretation of defect classifiers that are built using both approaches (i.e., discretized classifiers and regression-based classifiers) across six commonly used machine learning classifiers (i.e., linear/logistic regression, random forest, KNN, SVM, CART, and neural networks) and 17 datasets. We find that: i) Random forest based classifiers outperform other classifiers (best AUC) for both classifier building approaches, ii) In contrast to common practice, building a defect classifier using discretized defect counts (i.e., discretized classifiers) does not always lead to better performance. Hence we suggest that future defect classification studies should consider building regression-based classifiers (in particular when the defective ratio of the modeled dataset is low). Moreover, we suggest that both approaches for building defect classifiers should be explored, so the best-performing classifier can be used when determining the most influential features. Gopi Krishnan Rajbahadur, Shaowei Wang 0002, Yasutaka Kamei, Ahmed E. Hassan |
MSR | 1 |