activity
20212026
most citedFast and Exact Outlier Detection in Metric Spaces: A Proximity Graph-based Approach

3 citations · 9 across the 16 of their papers we have counts for

collaborators

16 papers

cs.DB2026

Duration-constrained Interval Joins

Naoya Ehara, Daichi Amagata

Many databases, including temporal, uncertain, spatial, and trajectory databases, use interval data, and interval joins are among the most frequently used operators. Many studies p…

cs.DB2026

Simple and Fast Algorithm for Graph-based Filtered Approximate Nearest Neighbor Search (Full Version)

Reon Uemura, Keito Kido, Daichi Amagata

It has been common to represent many objects as high-dimensional vectors due to the proliferation of machine learning-based embedding techniques. One of the most important function…

cs.LG2025

How Should We Evaluate Data Deletion in Graph-Based ANN Indexes?

Tomohiro Yamashita, Daichi Amagata, Yusuke Matsui

Approximate Nearest Neighbor Search (ANNS) has recently gained significant attention due to its many applications, such as Retrieval-Augmented Generation. Such applications require…

cs.DB2025

Random Sampling over Spatial Range Joins

Daichi Amagata

Spatial range joins have many applications, including geographic information systems, location-based social networking services, neuroscience, and visualization. However, joins inc…

cs.DB2025

Approximate Reverse -Ranks Queries in High Dimensions

Daichi Amagata, Kazuyoshi Aoyama, Keito Kido +1

Many objects are represented as high-dimensional vectors nowadays. In this setting, the relevance between two objects (vectors) is usually evaluated by their inner product. Recentl…

cs.DB2025

How to Mine Potentially Popular Items? A Reverse MIPS-based Approach

Daichi Amagata, Kazuyoshi Aoayama, Keito Kido +1

The -MIPS ( Maximum Inner Product Search) problem has been employed in many fields. Recently, its reverse version, the reverse -MIPS problem, has been proposed. Given an i…

cs.DB2024★ 1 cited

Independent Range Sampling on Interval Data (Longer Version)

Daichi Amagata

Many applications require efficient management of large sets of intervals because many objects are associated with intervals (e.g., time and price intervals). In such interval mana…

cs.DB2024★ 1 cited

Efficient Algorithms for Top-k Stabbing Queries on Weighted Interval Data (Full Version)

Daichi Amagata, Junya Yamada, Yuchen Ji +1

Intervals have been generated in many applications (e.g., temporal databases), and they are often associated with weights, such as prices. This paper addresses the problem of proce…

cs.DB2023

Fast Algorithm for Embedded Order Dependency Validation (Extended Version)

Alejandro Ramos, Takuya Uemura, Daichi Amagata +2

Order Dependencies (ODs) have many applications, such as query optimization, data integration, and data cleaning. Although many works addressed the problem of discovering OD (and i…

cs.DB2023

Learned spatial data partitioning

Keizo Hori, Yuya Sasaki, Daichi Amagata +2

Due to the significant increase in the size of spatial data, it is essential to use distributed parallel processing systems to efficiently analyze spatial data. In this paper, we f…

cs.IR2022★ 2 cited

Debiasing Graph Transfer Learning via Item Semantic Clustering for Cross-Domain Recommendations

Zhi Li, Daichi Amagata, Yihong Zhang +4

Deep learning-based recommender systems may lead to over-fitting when lacking training interaction data. This over-fitting significantly degrades recommendation performances. To ad…

cs.DB2022

Learned k-NN Distance Estimation

Daichi Amagata, Yusuke Arai, Sumio Fujita +1

Big data mining is well known to be an important task for data science, because it can provide useful observations and new knowledge hidden in given large datasets. Proximity-based…

cs.DB2022★ 2 cited

Fast Density-Peaks Clustering: Multicore-based Parallelization Approach

Daichi Amagata, Takahiro Hara

Clustering multi-dimensional points is a fundamental task in many fields, and density-based clustering supports many applications as it can discover clusters of arbitrary shapes. T…

cs.DB2021★ 3 cited

Fast and Exact Outlier Detection in Metric Spaces: A Proximity Graph-based Approach

Daichi Amagata, Makoto Onizuka, Takahiro Hara

Distance-based outlier detection is widely adopted in many fields, e.g., data mining and machine learning, because it is unsupervised, can be employed in a generic metric space, an…

cs.DB2021

Reverse Maximum Inner Product Search: How to efficiently find users who would like to buy my item?

Daichi Amagata, Takahiro Hara

The MIPS (maximum inner product search), which finds the item with the highest inner product with a given query user, is an essential problem in the recommendation field. It is usu…

cs.DB2021

Distributed Spatial-Keyword kNN Monitoring for Location-aware Pub/Sub

Shohei Tsuruoka, Daichi Amagata, Shunya Nishio +1

Recent applications employ publish/subscribe (Pub/Sub) systems so that publishers can easily receive attentions of customers and subscribers can monitor useful information generate…