Search Results for author: Jeffrey Chan

Found 29 papers, 8 papers with code

High-dimensional Bayesian Optimization via Covariance Matrix Adaptation Strategy

1 code implementation5 Feb 2024 Lam Ngo, Huong Ha, Jeffrey Chan, Vu Nguyen, Hongyu Zhang

To address this issue, a promising solution is to use a local search strategy that partitions the search domain into local regions with high likelihood of containing the global optimum, and then use BO to optimize the objective function within these regions.

Bayesian Optimization

Counterfactual Explanations via Locally-guided Sequential Algorithmic Recourse

no code implementations8 Sep 2023 Edward A. Small, Jeffrey N. Clark, Christopher J. McWilliams, Kacper Sokol, Jeffrey Chan, Flora D. Salim, Raul Santos-Rodriguez

Counterfactuals operationalised through algorithmic recourse have become a powerful tool to make artificial intelligence systems explainable.

counterfactual

i-Align: an interpretable knowledge graph alignment model

no code implementations26 Aug 2023 Bayu Distiawan Trisedya, Flora D Salim, Jeffrey Chan, Damiano Spina, Falk Scholer, Mark Sanderson

One of the strategies to address this problem is KG alignment, i. e., forming a more complete KG by merging two or more KGs.

Knowledge Graphs

Equalised Odds is not Equal Individual Odds: Post-processing for Group and Individual Fairness

1 code implementation19 Apr 2023 Edward A. Small, Kacper Sokol, Daniel Manning, Flora D. Salim, Jeffrey Chan

Group fairness is achieved by equalising prediction distributions between protected sub-populations; individual fairness requires treating similar individuals alike.

Fairness

More Is Less: When Do Recommenders Underperform for Data-rich Users?

no code implementations15 Apr 2023 Yueqing Xuan, Kacper Sokol, Jeffrey Chan, Mark Sanderson

Users of recommender systems tend to differ in their level of interaction with these algorithms, which may affect the quality of recommendations they receive and lead to undesirable performance disparity.

Recommendation Systems

How Robust is your Fair Model? Exploring the Robustness of Diverse Fairness Strategies

1 code implementation11 Jul 2022 Edward Small, Wei Shao, Zeliang Zhang, Peihan Liu, Jeffrey Chan, Kacper Sokol, Flora Salim

Recent studies have shown that robustness (the ability for a model to perform well on unseen data) plays a significant role in the type of strategy that should be used when approaching a new problem and, hence, measuring the robustness of these strategies has become a fundamental problem.

Decision Making Fairness +1

Sample-Efficient, Exploration-Based Policy Optimisation for Routing Problems

no code implementations31 May 2022 Nasrin Sultana, Jeffrey Chan, Tabinda Sarwar, A. K. Qin

In this paper, we show that our model can generalise to various route problems, such as the split-delivery VRP (SDVRP), and compare the performance of our method with that of current state-of-the-art approaches.

Efficient Exploration reinforcement-learning +1

Cross-model Fairness: Empirical Study of Fairness and Ethics Under Model Multiplicity

2 code implementations14 Mar 2022 Kacper Sokol, Meelis Kull, Jeffrey Chan, Flora Dilys Salim

While data-driven predictive models are a strictly technological construct, they may operate within a social context in which benign engineering choices entail implicit, indirect and unexpected real-life consequences.

Ethics Fairness

Measuring disentangled generative spatio-temporal representation

no code implementations10 Feb 2022 Sichen Zhao, Wei Shao, Jeffrey Chan, Flora D. Salim

Disentangled representation learning offers useful properties such as dimension reduction and interpretability, which are essential to modern deep learning approaches.

Dimensionality Reduction Representation Learning

Spatio-temporal Disentangled representation learning for mobility prediction

no code implementations29 Sep 2021 Sichen Zhao, Wei Shao, Jeffrey Chan, Flora D. Salim

In this work, we propose a VAE-based architecture for learning the disentangled representation from real spatio-temporal data for mobility forecasting.

Management Representation Learning

Learning Enhanced Optimisation for Routing Problems

no code implementations17 Sep 2021 Nasrin Sultana, Jeffrey Chan, Tabinda Sarwar, Babak Abbasi, A. K. Qin

However, there is still a substantial gap in solution quality between machine learning and operations research algorithms.

BIG-bench Machine Learning

MoParkeR : Multi-objective Parking Recommendation

no code implementations10 Jun 2021 Mohammad Saiedur Rahaman, Wei Shao, Flora D. Salim, Ayad Turky, Andy Song, Jeffrey Chan, Junliang Jiang, Doug Bradbrook

Existing parking recommendation solutions mainly focus on finding and suggesting parking spaces based on the unoccupied options only.

Recommendation Systems

Parallelizing Contextual Bandits

no code implementations21 May 2021 Jeffrey Chan, Aldo Pacchiano, Nilesh Tripuraneni, Yun S. Song, Peter Bartlett, Michael I. Jordan

Standard approaches to decision-making under uncertainty focus on sequential exploration of the space of decisions.

Decision Making Decision Making Under Uncertainty +1

Detecting Singleton Spams in Reviews via Learning Deep Anomalous Temporal Aspect-Sentiment Patterns

1 code implementation2 Jan 2021 Yassien Shaalan, Xiuzhen Zhang, Jeffrey Chan, Mahsa Salehi

Meanwhile, opinion spams spread widely and the detection of spam reviews becomes critically important for ensuring the integrity of the echo system of online reviews.

Feature Engineering

Learning Vehicle Routing Problems using Policy Optimisation

no code implementations24 Dec 2020 Nasrin Sultana, Jeffrey Chan, A. K. Qin, Tabinda Sarwar

In our evaluation, we experimentally illustrate that the model produces state-of-the-art performance on variants of Vehicle Routing problems such as Capacitated Vehicle Routing Problem (CVRP), Multiple Routing with Fixed Fleet Problems (MRPFF) and Travelling Salesman problem.

reinforcement-learning Reinforcement Learning (RL)

Divide and Learn: A Divide and Conquer Approach for Predict+Optimize

no code implementations4 Dec 2020 Ali Ugur Guler, Emir Demirovic, Jeffrey Chan, James Bailey, Christopher Leckie, Peter J. Stuckey

We compare our approach withother approaches to the predict+optimize problem and showwe can successfully tackle some hard combinatorial problemsbetter than other predict+optimize methods.

Combinatorial Optimization

Representing and Denoising Wearable ECG Recordings

no code implementations30 Nov 2020 Jeffrey Chan, Andrew C. Miller, Emily B. Fox

In this work, we develop a statistical model to simulate a structured noise process in ECGs derived from a wearable sensor, design a beat-to-beat representation that is conducive for analyzing variation, and devise a factor analysis-based method to denoise the ECG.

Denoising

Learning to Optimise General TSP Instances

no code implementations23 Oct 2020 Nasrin Sultana, Jeffrey Chan, A. K. Qin, Tabinda Sarwar

In recent years, learning to optimise approaches have shown success in solving TSP problems.

Meta-Learning

Joint Modelling of Cyber Activities and Physical Context to Improve Prediction of Visitor Behaviors

no code implementations26 Aug 2020 Manpreet Kaur, Flora D. Salim, Yongli Ren, Jeffrey Chan, Martin Tomko, Mark Sanderson

This paper investigates the Cyber-Physical behavior of users in a large indoor shopping mall by leveraging anonymized (opt in) Wi-Fi association and browsing logs recorded by the mall operators.

intent-classification Intent Classification

Less is More: Rejecting Unreliable Reviews for Product Question Answering

1 code implementation9 Jul 2020 Shiwei Zhang, Xiuzhen Zhang, Jey Han Lau, Jeffrey Chan, Cecile Paris

In the literature, PQA is formulated as a retrieval problem with the goal to search for the most relevant reviews to answer a given product question.

Community Question Answering Conformal Prediction +1

An Ambient-Physical System to Infer Concentration in Open-plan Workplace

no code implementations27 May 2020 Mohammad Saiedur Rahaman, Jonathan Liono, Yongli Ren, Jeffrey Chan, Shaw Kudo, Tim Rawling, Flora D. Salim

One of the core challenges in open-plan workspaces is to ensure a good level of concentration for the workers while performing their tasks.

Alternative Blockmodelling

no code implementations27 Jul 2019 Oscar Correa, Jeffrey Chan, Vinh Nguyen

Secondly, blockmodelling is a summary representation of a network which regards not only membership of nodes but also relations between clusters.

valid

Approximating Optimisation Solutions for Travelling Officer Problem with Customised Deep Learning Network

no code implementations8 Mar 2019 Wei Shao, Flora D. Salim, Jeffrey Chan, Sean Morrison, Fabio Zambetta

Deep learning has been extended to a number of new domains with critical success, though some traditional orienteering problems such as the Travelling Salesman Problem (TSP) and its variants are not commonly solved using such techniques.

General Classification

A Likelihood-Free Inference Framework for Population Genetic Data using Exchangeable Neural Networks

1 code implementation NeurIPS 2018 Jeffrey Chan, Valerio Perrone, Jeffrey P. Spence, Paul A. Jenkins, Sara Mathieson, Yun S. Song

To achieve this, two inferential challenges need to be addressed: (1) population data are exchangeable, calling for methods that efficiently exploit the symmetries of the data, and (2) computing likelihoods is intractable as it requires integrating over a set of correlated, extremely high-dimensional latent variables.

Ground Truth Bias in External Cluster Validity Indices

no code implementations17 Jun 2016 Yang Lei, James C. Bezdek, Simone Romano, Nguyen Xuan Vinh, Jeffrey Chan, James Bailey

For example, NCinc bias in the RI can be changed to NCdec bias by skewing the distribution of clusters in the ground truth partition.

Vocal Bursts Type Prediction

MOOCs Meet Measurement Theory: A Topic-Modelling Approach

no code implementations25 Nov 2015 Jiazhen He, Benjamin I. P. Rubinstein, James Bailey, Rui Zhang, Sandra Milligan, Jeffrey Chan

Such models infer latent skill levels by relating them to individuals' observed responses on a series of items such as quiz questions.

Topic Models

Cannot find the paper you are looking for? You can Submit a new open access paper.