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Bishwamittra Ghosh

PhD Student

Computer Science Department, School of Computing

National University of Singapore

Email: bishwa@comp.nus.edu.sg


I am a Ph.D. student in School of Computing, National University of Singapore (NUS). Currently, I am working under the supervision of Kuldeep Meel. My primary research interest is in interpretable machine learning model.


I have completed my BSc in Computer Science and Engineering from Department of Computer Science and Engineering, Bangladesh University of Engineering and Technology (BUET) in September 2017. My undergraduate thesis is on socio-spatial group queries under the supervision of Dr. Mohammed Eunus Ali. I have been a lecturer at United International University, Bangladesh for a short period of time. I love experimenting with ideas in CS by combining various formal techniques e.g., SAT, CP with interpretable classification models in machine learning.


News

My first paper during PhD on interpretable classification rules is accepted for publication at AIES 2019.

My undergrad thesis work on socio spatial group queries is accepted for publication at VLDB 2019.

Education

National University of Singapore

Jan 2018 - On going

Ph.D. in Computer Science

Bangladesh University of Engineering and Technology

Feb 2013 - Sept 2017

BSc in Computer Science and Engineering

Conference Papers

2019

[c2]

IMLI: An Incremental Framework for MaxSAT-Based Learning of Interpretable Classification Rules

Bishwamittra Ghosh, Kuldeep S. Meel.

Proceedings of AIES, 2019.

PDF Code

The wide adoption of machine learning in the critical domains such as medical diagnosis, law, education had propelled the need for interpretable techniques due to the need for end user to understand the reasoning behind decisions due to learning systems. The computational intractability of interpretable learning led practitioners to design heuristic techniques, which fail to provide sound handles to tradeoff accuracy and interpretability.

Motivated by the success of MaxSAT solvers over the past decade, recently MaxSAT-based approach, called MLIC, was proposed that seeks to reduce the problem of learning interpretable rules expressed in Conjunctive Normal Form (CNF) to a MaxSAT query. While MLIC was shown to achieve accuracy similar to that of other state oft he art black-box classifiers while generating small interpretable CNF formulas, the runtime performance of MLIC is significantly lagging and renders approach unusable in practice. In this context, authors raised the question: Is it possible to achieve the best of both worlds, i.e., a sound framework for interpretable learning that can take advantage of MaxSAT solvers while scaling to real-world instances?

In this paper, we take a step towards answering the above question in affirmation. We propose an incremental approach to MaxSAT based framework that achieves scalable runtime performance via partition-based training methodology. Extensive experiments on benchmarks arising from UCI repository demonstrate that IMLI achieves up to three orders of magnitude runtime improvement without loss of accuracy and interpretability.

[c1]

The Flexible Socio Spatial Group Queries

Bishwamittra Ghosh, Mohammed Eunus Ali, Farhana M. Choudhury,

Sajid Hasan Apon, Timos Sellis, Jianxin Li.

Proceedings of the VLDB Endowment (PVLDB), 2019.

PDF BibTex

A socio spatial group query finds a group of users who possess strong social connections with each other and have the minimum aggregate spatial distance to a meeting point. Existing studies limit the socio spatial group search to either finding best group of a fixed size for a single meeting location, or a single group of a fixed size w.r.t. multiple meeting locations. However, it is highly desirable to consider multiple meeting locations/POIs in a real-life scenario in order to organize impromptu activities of user groups of various sizes. In this paper, we propose Top k Flexible Socio Spatial Group Query (Top k-FSSGQ) to find and rank the top k groups w.r.t. multiple POIs where each group follows the minimum social connectivity constraints. We devise a ranking function to measure the group score by combining social closeness, spatial distance, and group size, which provides the flexibility of choosing groups of different sizes under different constraints. To effectively process the Top k-FSSGQ, we first develop an Exact approach that ensures early termination of the search based on the derived upper bounds. We prove that the problem is NP-hard, hence we first present a heuristic based approximation algorithm to effectively select members in intermediate solution groups based on the social connectivity of the users. Later we design a Fast Approximate approach based on the relaxed social and spatial bounds, and connectivity constraint heuristic. Experimental studies have verified the effectiveness and efficiency of our proposed approaches on real datasets.