User-oriented recommender systems in retail

User satisfaction is considered a key objective for all service provider platforms, regardless of the nature of the service, encompassing domains such as media, entertainment, retail, and information. While the goal of satisfying users is the same across different domains and services, considering domain-specific characteristics is of paramount importance to ensure users have a positive experience with a given system. User interaction data with a system is one of the main sources of data that facilitates achieving this goal. In this thesis, we investigate how to learn from domain-specific user interactions. We focus on recommendation as our main task, and retail as our main domain. We further explore the finance domain and the demand forecasting task as additional directions to understand whether our methodology and findings generalize to other tasks and domains. The research in this thesis is organized around the following dimensions: 1) Characteristics of multi-channel retail: we consider a retail setting where interaction data comes from both digital (i.e., online) and in-store (i.e., offline) shopping; 2) From user behavior to recommendation: we conduct extensive descriptive studies on user interaction log datasets that inform the design of recommender systems in two domains, retail and finance. Our key contributions in characterizing multi-channel retail are two-fold. First, we propose a neural model that makes use of sales in multiple shopping channels in order to improve the performance of demand forecasting in a target channel. Second, we provide the first study of user behavior in a multi-channel retail setting, which results in insights about the channel-specific properties of user behavior, and their effects on the performance of recommender systems. We make three main contributions in designing user-oriented recommender systems. First, we provide a large-scale user behavior study in the finance domain, targeted at understanding financial information seeking behavior in user interactions with company filings. We then propose domain-specific user-oriented filing recommender systems that are informed by the findings of the user behavior analysis. Second, we analyze repurchasing behavior in retail, specifically in the grocery shopping domain. We then propose a repeat consumption-aware neural recommender for this domain. Third, we focus on scalable recommendation in retail and propose an efficient recommender system that explicitly models users' personal preferences that are reflected in their purchasing history

User-oriented recommender systems in retail

User satisfaction is considered a key objective for all service provider platforms, regardless of the nature of the service, encompassing domains such as media, entertainment, retail, and information. While the goal of satisfying users is the same across different domains and services, considering domain-specific characteristics is of paramount importance to ensure users have a positive experience with a given system. User interaction data with a system is one of the main sources of data that facilitates achieving this goal. In this thesis, we investigate how to learn from domain-specific user interactions. We focus on recommendation as our main task, and retail as our main domain. We further explore the finance domain and the demand forecasting task as additional directions to understand whether our methodology and findings generalize to other tasks and domains. The research in this thesis is organized around the following dimensions: 1) Characteristics of multi-channel retail: we consider a retail setting where interaction data comes from both digital (i.e., online) and in-store (i.e., offline) shopping; 2) From user behavior to recommendation: we conduct extensive descriptive studies on user interaction log datasets that inform the design of recommender systems in two domains, retail and finance. Our key contributions in characterizing multi-channel retail are two-fold. First, we propose a neural model that makes use of sales in multiple shopping channels in order to improve the performance of demand forecasting in a target channel. Second, we provide the first study of user behavior in a multi-channel retail setting, which results in insights about the channel-specific properties of user behavior, and their effects on the performance of recommender systems. We make three main contributions in designing user-oriented recommender systems. First, we provide a large-scale user behavior study in the finance domain, targeted at understanding financial information seeking behavior in user interactions with company filings. We then propose domain-specific user-oriented filing recommender systems that are informed by the findings of the user behavior analysis. Second, we analyze repurchasing behavior in retail, specifically in the grocery shopping domain. We then propose a repeat consumption-aware neural recommender for this domain. Third, we focus on scalable recommendation in retail and propose an efficient recommender system that explicitly models users' personal preferences that are reflected in their purchasing history

Variational Bayesian Context-aware Representation for Grocery Recommendation

Grocery recommendation is an important recommendation use-case, which aims to predict which items a user might choose to buy in the future, based on their shopping history. However, existing methods only represent each user and item by single deterministic points in a low-dimensional continuous space. In addition, most of these methods are trained by maximizing the co-occurrence likelihood with a simple Skip-gram-based formulation, which limits the expressive ability of their embeddings and the resulting recommendation performance. In this paper, we propose the Variational Bayesian Context-Aware Representation (VBCAR) model for grocery recommendation, which is a novel variational Bayesian model that learns the user and item latent vectors by leveraging basket context information from past user-item interactions. We train our VBCAR model based on the Bayesian Skip-gram framework coupled with the amortized variational inference so that it can learn more expressive latent representations that integrate both the non-linearity and Bayesian behaviour. Experiments conducted on a large real-world grocery recommendation dataset show that our proposed VBCAR model can significantly outperform existing state-of-the-art grocery recommendation methods

Event Tracker: a Text Analytics Platform for Use During Disasters

Emergency management organisations currently rely on a wide range of disparate tools and technologies to support the monitoring and management of events during crisis situations. This has a number of disadvantages, in terms of training time for new staff members, reliance on external services, and a lack of integration (and hence poor transfer of information) between those services. On the other hand, Event Tracker is a new solution that aims to provide a unified view of an event, integrating information from emergency response officers, the public (via social media) and also volunteers from around the world. In particular, Event Tracker provides a series of novel functionalities to realise this unified view of the event, namely: real-time identification of critical information, automatic grouping of content by the information needs of response officers, as well as real-time volunteers management and communication. This is supported by an efficient and scalable back-end infrastructure designed to ingest and process high-volumes of real-time streaming data with low latency

Recommender Systems for Grocery Retail - A Machine Learning Approach

Recommender systems are present in our daily activities in different moments, such as when choosing a song to listen to or when doing online shopping. It is an everyday reality for people to have the help of computer systems in order to simplify regular decision activities. Grocery shopping is an essential part of people’s life and a frequent activity. Despite being a common habit, each customer has unique routines, needs and preferences regarding products and brands. This information is valuable for grocery retailers to know their customers better and to improve their marketing and operational activities. This dissertation aims to apply machine learning algorithms to the development of a recommender system capable of preparing personalized grocery shopping lists. The proposed architecture is designed to allow integration with different grocery retailers and support distinct TensorFlow algorithms. The process of extracting information from the dataset as features was explored, as well as the tuning of the model hyperparameters, to obtain better results. The recommendation engine is exposed via a distributed software architecture designed to allow retailers to integrate the recommender system with different existing solutions (e.g., websites or mobile applications). A case study to validate the implemented solution was performed, integrating it with a public dataset provided by Instacart. A comparison study between different machine learning algorithms over the adopted dataset has lead to the choice of the gradient boosted trees algorithm. The solution developed in the case study was compared against two non-machine learning approaches at predicting the last purchase of 360 arbitrary test customers. A pattern miningbased solution and a SQL-based heuristic were used. Different evaluation metrics (namely, the average accuracy, precision, recall, and f1-score) were registered. The way association rules with different strengths were reflected in the predictions of the developed solution was also analyzed. The gradient boosted trees-based implementation from the case study was capable of outperforming the compared solutions as far as evaluation metrics are concerned, and has shown a higher capability of predicting at least one correct item per customer. Also, it became evident that the strictest association rules were frequently found in the recommendations. The adopted solution and algorithm have shown promising results and a remarkable capability to provide meaningful predictions to the different customers, evidencing its capability to add value to grocery retail. Nevertheless, there is still potential for further expansion.Os sistemas de recomendação estão presentes no nosso quotidiano, em momentos como a escolha da música a ouvir ou a preparação de compras online. Estamos acostumados a contar com a ajuda de sistemas computacionais para simplificar tarefas habituais que envolvem decisões. Realizar compras de retalho alimentar é uma parte importante e frequente da nossa vida. Apesar de ser um hábito comum, cada um de nós tem as suas próprias rotinas, necessidades e preferências no que toca a produtos e marcas. Esta informação é valiosa para que os retalhistas alimentares consigam conhecer melhor os seus clientes e melhorar atividades operacionais e de marketing. Esta dissertação tem como objetivo a aplicação de algoritmos de machine learning na criação de um sistema de recomendação capaz de preparar listas de compras personalizadas. A arquitetura proposta é desenhada com o objetivo de permitir a integração com diferentes retalhistas e a utilização de diferentes algoritmos em TensorFlow. O processo de extração de informação na forma de features foi explorado, tal como a afinação dos hiperparâmetros do modelo, para obter melhores resultados. O motor de recomendações é exposto através de uma arquitetura de software distribuída, com o propósito de permitir que os retalhistas alimentares possam integrar este sistema com diferentes soluções existentes (e.g., websites ou aplicações móveis). Foi realizado um caso de estudo para validar a solução implementada, através da integração da solução com os dados públicos disponibilizados pelo retalhista Instacart. Uma comparação entre a aplicação de diferentes algoritmos de machine learning aos dados utilizados, levou à adoção do algoritmo gradient boosted trees. A solução desenvolvida no caso de estudo foi comparada com duas abordagens não baseadas em machine learning para a previsão da última compra de 360 clientes arbitrários. Foi usada uma abordagem baseada em pattern mining e uma abordagem baseada em SQL. Diferentes métricas de avaliação (nomeadamente accuracy, precision, recall e f1-score médios) foram registadas. Foi também analisada a forma como diferentes regras de associação se encontraram refletidas nas recomendações da solução desenvolvida. A implementação baseada em gradient boosted trees do caso de estudo superou as soluções com as quais foi comparada quanto às métricas de avaliação, e mostrou uma maior capacidade de recomendar pelo menos um produto correto por cliente. Verificou-se também que as regras de associação mais fortes estão frequentemente refletidas nas recomendações. A abordagem adotada e o algoritmo aprofundado mostraram resultados promissores e uma capacidade notável de fornecer recomendações úteis aos diferentes clientes, evidenciando a sua aptidão para adicionar valor ao retalho alimentar. Ainda assim, este sistema apresenta um elevado potencial para expansão