1 code implementation • 15 Jul 2024 • Akifumi Okuno
This paper presents an integrated perspective on robustness in regression.
2 code implementations • 4 Aug 2023 • Akifumi Okuno
While the $(k, q)$-VR terms applied to general parametric models are computationally intractable due to the integration, this study provides a stochastic optimization algorithm, that can efficiently train general models with the $(k, q)$-VR without conducting explicit numerical integration.
1 code implementation • 11 Jul 2023 • Akifumi Okuno
Density power divergence (DPD) is designed to robustly estimate the underlying distribution of observations, in the presence of outliers.
1 code implementation • 28 Jun 2023 • Akifumi Okuno, Yuya Morishita, Yoh-ichi Mototake
This study delves into the domain of dynamical systems, specifically the forecasting of dynamical time series defined through an evolution function.
1 code implementation • 31 Mar 2023 • Akifumi Okuno, Kazuharu Harada
This study proposes an interpretable neural network-based non-proportional odds model (N$^3$POM) for ordinal regression.
1 code implementation • 18 Apr 2022 • Akifumi Okuno, Kohei Hattori
In this study, we examine a clustering problem in which the covariates of each individual element in a dataset are associated with an uncertainty specific to that element.
no code implementations • 28 Dec 2021 • Ruixing Cao, Akifumi Okuno, Kei Nakagawa, Hidetoshi Shimodaira
For correcting the asymptotic bias with fewer observations, this paper proposes a \emph{local radial regression (LRR)} and its logistic regression variant called \emph{local radial logistic regression~(LRLR)}, by combining the advantages of LPoR and MS-$k$-NN.
no code implementations • 7 Dec 2021 • Akifumi Okuno, Keisuke Yano
This paper discusses the estimation of the generalization gap, the difference between generalization performance and training performance, for overparameterized models including neural networks.
1 code implementation • 1 Dec 2021 • Akifumi Okuno, Masaaki Imaizumi
The derived minimax rate corresponds to that of the non-invertible bi-Lipschitz function, which shows that the invertibility does not reduce the complexity of the estimation problem in terms of the rate.
no code implementations • 24 Dec 2020 • Akifumi Okuno, Keisuke Yano
This paper discusses a design-dependent nature of variance in nonparametric link regression aiming at predicting a mean outcome at a link, i. e., a pair of nodes, based on currently observed data comprising covariates at nodes and outcomes at links.
Statistics Theory Statistics Theory
no code implementations • NeurIPS 2020 • Akifumi Okuno, Hidetoshi Shimodaira
The weights and the parameter $k \in \mathbb{N}$ regulate its bias-variance trade-off, and the trade-off implicitly affects the convergence rate of the excess risk for the $k$-NN classifier; several existing studies considered selecting optimal $k$ and weights to obtain faster convergence rate.
no code implementations • 2 May 2020 • Morihiro Mizutani, Akifumi Okuno, Geewook Kim, Hidetoshi Shimodaira
Multimodal relational data analysis has become of increasing importance in recent years, for exploring across different domains of data, such as images and their text tags obtained from social networking services (e. g., Flickr).
no code implementations • 8 Feb 2020 • Akifumi Okuno, Hidetoshi Shimodaira
The weights and the parameter $k \in \mathbb{N}$ regulate its bias-variance trade-off, and the trade-off implicitly affects the convergence rate of the excess risk for the $k$-NN classifier; several existing studies considered selecting optimal $k$ and weights to obtain faster convergence rate.
no code implementations • 22 Jul 2019 • Akifumi Okuno, Hidetoshi Shimodaira
A collection of $U \: (\in \mathbb{N})$ data vectors is called a $U$-tuple, and the association strength among the vectors of a tuple is termed as the \emph{hyperlink weight}, that is assumed to be symmetric with respect to permutation of the entries in the index.
1 code implementation • 27 Feb 2019 • Geewook Kim, Akifumi Okuno, Kazuki Fukui, Hidetoshi Shimodaira
In addition to the parameters of neural networks, we optimize the weights of the inner product by allowing positive and negative values.
no code implementations • 22 Feb 2019 • Akifumi Okuno, Hidetoshi Shimodaira
We propose $\beta$-graph embedding for robustly learning feature vectors from data vectors and noisy link weights.
no code implementations • 4 Oct 2018 • Akifumi Okuno, Geewook Kim, Hidetoshi Shimodaira
We propose shifted inner-product similarity (SIPS), which is a novel yet very simple extension of the ordinary inner-product similarity (IPS) for neural-network based graph embedding (GE).
no code implementations • 31 May 2018 • Akifumi Okuno, Hidetoshi Shimodaira
We consider the representation power of siamese-style similarity functions used in neural network-based graph embedding.
no code implementations • ICML 2018 • Akifumi Okuno, Tetsuya Hada, Hidetoshi Shimodaira
PMvGE is a probabilistic model for predicting new associations via graph embedding of the nodes of data vectors with links of their associations.