Implicit vs. Explicit Trust in Social Matrix Factorization

This poster presented at the RecSys2014, Silicon Valley, US Oct. 6th-10th, 2014.NELLL, EU FP7 LAC

Recommendation with the Right Slice: Speeding Up Collaborative Filtering with Factorization Machines

ABSTRACT We propose an alternative way to efficiently exploit rating data for collaborative filtering with Factorization Machines (FMs). Our approach partitions user-item matrix into 'slices' which are mutually exclusive with respect to items. The training phase makes direct use of the slice of interest (target slice), while incorporating information from other slices indirectly. FMs represent user-item interactions as feature vectors, and they offer the advantage of easy incorporation of complementary information. We exploit this advantage to integrate information from other auxiliary slices. We demonstrate, using experiments on two benchmark datasets, that improved performance can be achieved, while the time complexity of training can be reduced significantly

Cross-domain collaborative filtering with factorization machines.

Abstract. Factorization machines offer an advantage over other existing collaborative filtering approaches to recommendation. They make it possible to work with any auxiliary information that can be encoded as a real-valued feature vector as a supplement to the information in the user-item matrix. We build on the assumption that different patterns characterize the way that users interact with (i.e., rate or download) items of a certain type (e.g., movies or books). We view interactions with a specific type of item as constituting a particular domain and allow interaction information from an auxiliary domain to inform recommendation in a target domain. Our proposed approach is tested on a data set from Amazon and compared with a state-of-the-art approach that has been proposed for Cross-Domain Collaborative Filtering. Experimental results demonstrate that our approach, which has a lower computational complexity, is able to achieve performance improvements

'Project smells' - Experiences in Analysing the Software Quality of ML Projects with mllint

Machine Learning (ML) projects incur novel challenges in their development and productionisation over traditional software applications, though established principles and best practices in ensuring the project's software quality still apply. While using static analysis to catch code smells has been shown to improve software quality attributes, it is only a small piece of the software quality puzzle, especially in the case of ML projects given their additional challenges and lower degree of Software Engineering (SE) experience in the data scientists that develop them. We introduce the novel concept of project smells which consider deficits in project management as a more holistic perspective on software quality in ML projects. An open-source static analysis tool mllint was also implemented to help detect and mitigate these. Our research evaluates this novel concept of project smells in the industrial context of ING, a global bank and large software- and data-intensive organisation. We also investigate the perceived importance of these project smells for proof-of-concept versus production-ready ML projects, as well as the perceived obstructions and benefits to using static analysis tools such as mllint. Our findings indicate a need for context-aware static analysis tools, that fit the needs of the project at its current stage of development, while requiring minimal configuration effort from the user. Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Software EngineeringSoftware Technolog

Getting by with a Little Help from the Crowd: Practical Approaches to Social Image Labeling

International audienceValidating user tags helps to refine them, making them more useful for finding images. In the case of interpretation-sensitive tags, however, automatic (i.e., pixel-based) approaches cannot be expected to deliver optimal results. Instead, human input is the key. This paper studies how crowdsourcing-based approaches to image tag validation can achieve parsimony in their use of human input from the crowd, in the form of votes collected from workers on a crowdsourcing platform. Experiments in the domain of social fashion images are carried out using the dataset published by the Crowdsourcing Task of the Mediaeval 2013 Multimedia Benchmark. Experimental results reveal that when a larger number of crowd-contributed votes are available, it is difficult to beat a majority vote. However, additional information sources, i.e., crowdworker history and visual image features, allow us to maintain similar validation performance while making use of less crowd-contributed input. Further, investing in expensive experts who collaborate to create definitions of interpretation-sensitive concepts does not necessarily pay off. Instead, experts can cause interpretations of concepts to drift away from conventional wisdom. In short, validation of interpretation-sensitive user tags for social images is possible, with " just a little help from the crowd"