101 research outputs found
Improving Conversational Recommendation Systems via Bias Analysis and Language-Model-Enhanced Data Augmentation
Conversational Recommendation System (CRS) is a rapidly growing research area
that has gained significant attention alongside advancements in language
modelling techniques. However, the current state of conversational
recommendation faces numerous challenges due to its relative novelty and
limited existing contributions. In this study, we delve into benchmark datasets
for developing CRS models and address potential biases arising from the
feedback loop inherent in multi-turn interactions, including selection bias and
multiple popularity bias variants. Drawing inspiration from the success of
generative data via using language models and data augmentation techniques, we
present two novel strategies, 'Once-Aug' and 'PopNudge', to enhance model
performance while mitigating biases. Through extensive experiments on ReDial
and TG-ReDial benchmark datasets, we show a consistent improvement of CRS
techniques with our data augmentation approaches and offer additional insights
on addressing multiple newly formulated biases.Comment: Accepted by EMNLP 2023 (Findings
Provider Fairness and Beyond-Accuracy Trade-offs in Recommender Systems
Recommender systems, while transformative in online user experiences, have
raised concerns over potential provider-side fairness issues. These systems may
inadvertently favor popular items, thereby marginalizing less popular ones and
compromising provider fairness. While previous research has recognized
provider-side fairness issues, the investigation into how these biases affect
beyond-accuracy aspects of recommendation systems - such as diversity, novelty,
coverage, and serendipity - has been less emphasized. In this paper, we address
this gap by introducing a simple yet effective post-processing re-ranking model
that prioritizes provider fairness, while simultaneously maintaining user
relevance and recommendation quality. We then conduct an in-depth evaluation of
the model's impact on various aspects of recommendation quality across multiple
datasets. Specifically, we apply the post-processing algorithm to four distinct
recommendation models across four varied domain datasets, assessing the
improvement in each metric, encompassing both accuracy and beyond-accuracy
aspects. This comprehensive analysis allows us to gauge the effectiveness of
our approach in mitigating provider biases. Our findings underscore the
effectiveness of the adopted method in improving provider fairness and
recommendation quality. They also provide valuable insights into the trade-offs
involved in achieving fairness in recommender systems, contributing to a more
nuanced understanding of this complex issue.Comment: FAccTRec at RecSys 202
Joint Geographical and Temporal Modeling based on Matrix Factorization for Point-of-Interest Recommendation
With the popularity of Location-based Social Networks, Point-of-Interest
(POI) recommendation has become an important task, which learns the users'
preferences and mobility patterns to recommend POIs. Previous studies show that
incorporating contextual information such as geographical and temporal
influences is necessary to improve POI recommendation by addressing the data
sparsity problem. However, existing methods model the geographical influence
based on the physical distance between POIs and users, while ignoring the
temporal characteristics of such geographical influences. In this paper, we
perform a study on the user mobility patterns where we find out that users'
check-ins happen around several centers depending on their current temporal
state. Next, we propose a spatio-temporal activity-centers algorithm to model
users' behavior more accurately. Finally, we demonstrate the effectiveness of
our proposed contextual model by incorporating it into the matrix factorization
model under two different settings: i) static and ii) temporal. To show the
effectiveness of our proposed method, which we refer to as STACP, we conduct
experiments on two well-known real-world datasets acquired from Gowalla and
Foursquare LBSNs. Experimental results show that the STACP model achieves a
statistically significant performance improvement, compared to the
state-of-the-art techniques. Also, we demonstrate the effectiveness of
capturing geographical and temporal information for modeling users' activity
centers and the importance of modeling them jointly.Comment: To be appear in ECIR 202
Category-Aware Location Embedding for Point-of-Interest Recommendation
Recently, Point of interest (POI) recommendation has gained ever-increasing
importance in various Location-Based Social Networks (LBSNs). With the recent
advances of neural models, much work has sought to leverage neural networks to
learn neural embeddings in a pre-training phase that achieve an improved
representation of POIs and consequently a better recommendation. However,
previous studies fail to capture crucial information about POIs such as
categorical information.
In this paper, we propose a novel neural model that generates a POI embedding
incorporating sequential and categorical information from POIs. Our model
consists of a check-in module and a category module. The check-in module
captures the geographical influence of POIs derived from the sequence of users'
check-ins, while the category module captures the characteristics of POIs
derived from the category information. To validate the efficacy of the model,
we experimented with two large-scale LBSN datasets. Our experimental results
demonstrate that our approach significantly outperforms state-of-the-art POI
recommendation methods.Comment: 4 pages, 1 figure
Detection of COVID-19 Using Heart Rate and Blood Pressure: Lessons Learned from Patients with ARDS
The world has been affected by COVID-19 coronavirus. At the time of this
study, the number of infected people in the United States is the highest
globally (7.9 million infections). Within the infected population, patients
diagnosed with acute respiratory distress syndrome (ARDS) are in more
life-threatening circumstances, resulting in severe respiratory system failure.
Various studies have investigated the infections to COVID-19 and ARDS by
monitoring laboratory metrics and symptoms. Unfortunately, these methods are
merely limited to clinical settings, and symptom-based methods are shown to be
ineffective. In contrast, vital signs (e.g., heart rate) have been utilized to
early-detect different respiratory diseases in ubiquitous health monitoring. We
posit that such biomarkers are informative in identifying ARDS patients
infected with COVID-19. In this study, we investigate the behavior of COVID-19
on ARDS patients by utilizing simple vital signs. We analyze the long-term
daily logs of blood pressure and heart rate associated with 70 ARDS patients
admitted to five University of California academic health centers (containing
42506 samples for each vital sign) to distinguish subjects with COVID-19
positive and negative test results. In addition to the statistical analysis, we
develop a deep neural network model to extract features from the longitudinal
data. Using only the first eight days of the data, our deep learning model is
able to achieve 78.79% accuracy to classify the vital signs of ARDS patients
infected with COVID-19 versus other ARDS diagnosed patients
Barriers to Family Caregivers’ Coping With Patients With Severe Mental Illness in Iran
The broad spectrum of problems caused by caring for a patient with mental illness imposes a high burden on family caregivers. This can affect how they cope with their mentally ill family members. Identifying caregivers’ experiences of barriers to coping is necessary to develop a program to help them overcome these challenges. This qualitative content analysis study explored barriers impeding family caregivers’ ability to cope with their relatives diagnosed with severe mental illness (defined here as schizophrenia, schizoaffective disorders, and bipolar affective disorders). Sixteen family caregivers were recruited using purposive sampling and interviewed using a semi-structured in-depth interview method. Data were analyzed by a conventional content analytic approach. Findings consisted of four major categories: the patient’s isolation from everyday life, incomplete recovery, lack of support by the mental health care system, and stigmatization. Findings highlight the necessity of providing support for caregivers by the mental health care delivery service system.The study was supported by Grant TBZMED·REC.5825 from the deputy of research in Tabriz University of Medical Sciences
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