Publications

On generalized surrogate duality in mixed-integer nonlinear programming

Benjamin Müller

Gonzalo Muñoz

Maxime Gasse

Ambros Gleixner

Andrea Lodi

Felipe Serrano

2020-04-14

Integer Programming and Combinatorial Optimization (published)

doi.org

arxiv.org

Clustering for Continuous-Time Hidden Markov Models.

Yu Luo

David A. Stephens

David Buckeridge

We develop clustering procedures for longitudinal trajectories based on a continuous-time hidden Markov model (CTHMM) and a generalized line… (see more)ar observation model. Specifically in this paper, we carry out infinite mixture model-based clustering for CTHMM and achieve inference using Markov chain Monte Carlo (MCMC). Specifically, for Bayesian nonparametric inference using a Dirichlet process mixture model, we utilize restricted Gibbs sampling split-merge proposals to expedite the MCMC algorithm. We employ the proposed algorithm to the simulated data as well as a large real data example, and the results demonstrate the desired performance of the new sampler.

2020-04-13

(published)

www.semanticscholar.org

CNN Detection of New and Enlarging Multiple Sclerosis Lesions from Longitudinal Mri Using Subtraction Images

Nazanin Mohammadi Sepahvand

Douglas Arnold

Tal Arbel

Accurate detection and segmentation of new lesional activity in longitudinal Magnetic Resonance Images (MRIs) of patients with Multiple Scle… (see more)rosis (MS) is important for monitoring disease activity, as well as for assessing treatment effects. In this work, we present the first deep learning framework to automatically detect and segment new and enlarging (NE) T2w lesions from longitudinal brain MRIs acquired from relapsing-remitting MS (RRMS) patients. The proposed framework is an adapted 3D U-Net [1] which includes as inputs the reference multi-modal MRI and T2-weighted lesion maps, as well an attention mechanism based on the subtraction MRI (between the two timepoints) which serves to assist the network in learning to differentiate between real anatomical change and artifactual change, while constraining the search space for small lesions. Experiments on a large, proprietary, multi -center, multi-modal, clinical trial dataset consisting of 1677 multi-modal scans illustrate that network achieves high overall detection accuracy (detection AUC=.95), outperforming (1) a U-Net without an attention mechanism (de-tection AUC=.93), (2) a framework based on subtracting independent T2-weighted segmentations (detection AUC=.57), and (3) DeepMedic (detection AUC=.84) [2], particularly for small lesions. In addition, the method was able to accurately classify patients as active/inactive with (sensitivities of. 69 and specificities of. 97).

2020-04-03

2020 IEEE 17th International Symposium on Biomedical Imaging (ISBI) (published)

doi.org

Literature Mining for Incorporating Inductive Bias in Biomedical Prediction Tasks (Student Abstract)

Qizhen Zhang

Audrey Durand

Joelle Pineau

2020-04-03

AAAI Conference on Artificial Intelligence (published)

doi.org

Modeling Dialogues with Hashcode Representations: A Nonparametric Approach

Sahil Garg

Irina Rish

Guillermo Cecchi

Palash Goyal

Shuyang Gao

Sarik Ghazarian

Greg Ver Steeg

Aram Galstyan

We propose a novel dialogue modeling framework, the first-ever nonparametric kernel functions based approach for dialogue modeling, which le… (see more)arns hashcodes as text representations; unlike traditional deep learning models, it handles well relatively small datasets, while also scaling to large ones. We also derive a novel lower bound on mutual information, used as a model-selection criterion favoring representations with better alignment between the utterances of participants in a collaborative dialogue setting, as well as higher predictability of the generated responses. As demonstrated on three real-life datasets, including prominently psychotherapy sessions, the proposed approach significantly outperforms several state-of-art neural network based dialogue systems, both in terms of computational efficiency, reducing training time from days or weeks to hours, and the response quality, achieving an order of magnitude improvement over competitors in frequency of being chosen as the best model by human evaluators.

2020-04-03

AAAI Conference on Artificial Intelligence (published)

doi.org

Options of Interest: Temporal Abstraction with Interest Functions

Khimya Khetarpal

Martin Klissarov

Maxime Chevalier-Boisvert

Pierre-Luc Bacon

Doina Precup

Temporal abstraction refers to the ability of an agent to use behaviours of controllers which act for a limited, variable amount of time. Th… (see more)e options framework describes such behaviours as consisting of a subset of states in which they can initiate, an internal policy and a stochastic termination condition. However, much of the subsequent work on option discovery has ignored the initiation set, because of difficulty in learning it from data. We provide a generalization of initiation sets suitable for general function approximation, by defining an interest function associated with an option. We derive a gradient-based learning algorithm for interest functions, leading to a new interest-option-critic architecture. We investigate how interest functions can be leveraged to learn interpretable and reusable temporal abstractions. We demonstrate the efficacy of the proposed approach through quantitative and qualitative results, in both discrete and continuous environments.

2020-04-03

Proceedings of the AAAI Conference on Artificial Intelligence (published)

doi.org

arxiv.org

GitHub Repositories with Links to Academic Papers: Open Access, Traceability, and Evolution

Supatsara Wattanakriengkrai

Bodin Chinthanet

Hideaki Hata

Raula Gaikovina Kula

Christoph Treude

Jin Guo

Ken-ichi Matsumoto

Traceability between published scientific breakthroughs and their implementation is essential, especially in the case of Open Source Softwar… (see more)e implements bleeding edge science into its code. However, aligning the link between GitHub repositories and academic papers can prove difficult, and the link impact remains unknown. This paper investigates the role of academic paper references contained in these repositories. We conducted a large-scale study of 20 thousand GitHub repositories to establish prevalence of references to academic papers. We use a mixed-methods approach to identify Open Access (OA), traceability and evolutionary aspects of the links. Although referencing a paper is not typical, we find that a vast majority of referenced academic papers are OA. In terms of traceability, our analysis revealed that machine learning is the most prevalent topic of repositories. These repositories tend to be affiliated with academic communities. More than half of the papers do not link back to any repository. A case study of referenced arXiv paper shows that most of these papers are high-impact and influential and do align with academia, referenced by repositories written in different programming languages. From the evolutionary aspect, we find very few changes of papers being referenced and links to them.

2020-04-01

arXiv.org (preprint)

dblp.uni-trier.de

Multi-language design smells: a backstage perspective

Mouna Abidi

Md Saidur Rahman

Moses Openja

Foutse Khomh

2020-04-01

Empirical Software Engineering (published)

doi.org

Multi-language design smells: a backstage perspective