activity
20202026
most citedFactorization Machines with Regularization for Sparse Feature Interactions

2 citations · 2 across the 10 of their papers we have counts for

collaborators

12 papers

cs.CL2026

NLData2Opt: Benchmarking Parameter Derivation and Prediction for Modeling Optimization Problems from Natural Language and Data

Lijia Liu, Kyohei Atarashi, Jiyi Li +3

Formulating optimization problems from raw inputs of problem descriptions and data is time-consuming and costly. While Large Language Models (LLMs) offer a promising way to automat…

math.AP2026

New result on Lane-Emden conjecture with exponents in a disk

Haoyang Lu, Zhitao Zhang

We obtain new results on Lane-Emden conjecture to prove a Liouville theorem for the Lane-Emden system $$\begin{cases} -Δu=v^p,& x\in \mathbb{R}^N,\\ -Δv=u^q,& x\in \mathbb{R}^N,\en…

cs.LG2026

Disentangling Steering Vectors

Takeru Hiramatsu, Kyohei Atarashi, Koh Takeuchi +1

Activation steering has emerged as a lightweight, inference-time approach to control the behavior of Large Language Models (LLMs). However, traditional steering vectors used to int…

cs.CY2026

Estimating Learners' Skill Acquisition Without Temporal Information

Ryosuke Nagai, Kyohei Atarashi, Koh Takeuchi +2

Recent research in educational data mining, especially knowledge tracing, has focused on predicting learners' future knowledge states to support adaptive instruction. However, in m…

cs.CL2026

Evaluating Cross-Modal Reasoning Ability and Problem Characteristics with Multimodal Item Response Theory

Shunki Uebayashi, Kento Masui, Kyohei Atarashi +5

Multimodal Large Language Models (MLLMs) have recently emerged as general architectures capable of reasoning over diverse modalities. Benchmarks for MLLMs should measure their abil…

cs.LG2025

Robust Anomaly Detection Under Normality Distribution Shift in Dynamic Graphs

Xiaoyang Xu, Xiaofeng Lin, Koh Takeuchi +2

Anomaly detection in dynamic graphs is a critical task with broad real-world applications, including social networks, e-commerce, and cybersecurity. Most existing methods assume th…

cs.LG2025

Unpacking the Implicit Norm Dynamics of Sharpness-Aware Minimization in Tensorized Models

Tianxiao Cao, Kyohei Atarashi, Hisashi Kashima

Sharpness-Aware Minimization (SAM) has been proven to be an effective optimization technique for improving generalization in overparameterized models. While prior works have explor…

cs.CR2025

Counterfactual Evaluation for Blind Attack Detection in LLM-based Evaluation Systems

Lijia Liu, Takumi Kondo, Kyohei Atarashi +4

This paper investigates defenses for LLM-based evaluation systems against prompt injection. We formalize a class of threats called blind attacks, where a candidate answer is crafte…

stat.ML2025

Probability Bounding: Post-Hoc Calibration via Box-Constrained Softmax

Kyohei Atarashi, Satoshi Oyama, Hiromi Arai +1

Many studies have observed that modern neural networks achieve high accuracy while producing poorly calibrated probabilities, making calibration a critical practical issue. In this…

cs.CV2025

Exploring Causes and Mitigation of Hallucinations in Large Vision Language Models

Yaqi Sun, Kyohei Atarashi, Koh Takeuchi +1

Large Vision-Language Models (LVLMs) integrate image encoders with Large Language Models (LLMs) to process multi-modal inputs and perform complex visual tasks. However, they often…

cs.CL2025

Emulating Retrieval Augmented Generation via Prompt Engineering for Enhanced Long Context Comprehension in LLMs

Joon Park, Kyohei Atarashi, Koh Takeuchi +1

This paper addresses the challenge of comprehending very long contexts in Large Language Models (LLMs) by proposing a method that emulates Retrieval Augmented Generation (RAG) thro…

stat.ML2020★ 2 cited

Factorization Machines with Regularization for Sparse Feature Interactions

Kyohei Atarashi, Satoshi Oyama, Masahito Kurihara

Factorization machines (FMs) are machine learning predictive models based on second-order feature interactions and FMs with sparse regularization are called sparse FMs. Such regula…