activity
20232026
most citedHierarchical Matrix Factorization for Interpretable Collaborative Filtering

8 citations · 10 across the 7 of their papers we have counts for

collaborators

9 papers

cs.CR2026

Trigger Value Selection in Clean-Label Malware Backdoors: An Effectiveness-Detectability Analysis

Tri Budi Sabdo Utomo, Kazushi Okamoto, Koki Karube +2

Clean-label backdoor poisoning is a threat to machine learning-based malware classifiers because poisoned samples can be inserted into training data without changing their labels.…

cs.CL2026

LLM-Based Weak Annotation for Cybersecurity Tweet Classification: A Teacher-Student Framework

Ferry Afit Kurniawan, Kazushi Okamoto, Koki Karube +2

Cyber threat intelligence (CTI) relies on the timely identification of emerging threats, enabling organizations and security analysts to support situational awareness and decision-…

cs.CV2025

Estimation of Fireproof Structure Class and Construction Year for Disaster Risk Assessment

Hibiki Ayabe, Kazushi Okamoto, Koki Karube +2

Structural fireproof classification is vital for disaster risk assessment and insurance pricing in Japan. However, key building metadata such as construction year and structure typ…

cs.IR2025

Generation and annotation of item usage scenarios in e-commerce using large language models

Madoka Hagiri, Kazushi Okamoto, Koki Karube +2

Complementary recommendations suggest combinations of useful items that play important roles in e-commerce. However, complementary relationships are often subjective and vary among…

cs.IR2025

Knowledge-Augmented Relation Learning for Complementary Recommendation with Large Language Models

Chihiro Yamasaki, Kai Sugahara, Kazushi Okamoto

Complementary recommendations play a crucial role in e-commerce by enhancing user experience through suggestions of compatible items. Accurate classification of complementary item…

cs.IR2025

A Universal Framework for Offline Serendipity Evaluation in Recommender Systems via Large Language Models

Yu Tokutake, Kazushi Okamoto, Kei Harada +2

Serendipity in recommender systems (RSs) has attracted increasing attention as a concept that enhances user satisfaction by presenting unexpected and useful items. However, evaluat…

cs.IR2025

Function-based Labels for Complementary Recommendation: Definition, Annotation, and LLM-as-a-Judge

Chihiro Yamasaki, Kai Sugahara, Yuma Nagi +1

Complementary recommendations enhance the user experience by suggesting items that are frequently purchased together while serving different functions from the query item. Inferrin…

cs.IR2024★ 2 cited

Can Large Language Models Assess Serendipity in Recommender Systems?

Yu Tokutake, Kazushi Okamoto

Serendipity-oriented recommender systems aim to counteract over-specialization in user preferences. However, evaluating a user's serendipitous response towards a recommended item c…

cs.IR2023★ 8 cited

Hierarchical Matrix Factorization for Interpretable Collaborative Filtering

Kai Sugahara, Kazushi Okamoto

Matrix factorization (MF) is a simple collaborative filtering technique that achieves superior recommendation accuracy by decomposing the user-item interaction matrix into user and…