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Hiroshi Sawada

11 accepted papers

2026

FedPM: Federated Learning Using Second-order Optimization with Preconditioned Mixing of Local Parameters

AAAI 2026technical

We propose Federated Preconditioned Mixing (FedPM), a novel Federated Learning (FL) method that leverages second-order optimization. Prior methods - such as LocalNewton, LTDA, and FedSophia - have incorporated second-order optimization in FL by performing iterative local updates on clients and apply

Cited by 0SourcePDFScholar
2025

Guided Zeroth-Order Methods for Stochastic Non-convex Problems with Decision-Dependent Distributions

ICML 2025poster

In this study, we tackle an optimization problem with a known function and an unknown decision-dependent distribution, which arises in a variety of applications and is often referred to as a performative prediction problem. To solve the problem, several zeroth-order methods have been developed becau…

Cited by 0SourcePDFScholar
2025

Layered-Parameter Perturbation for Zeroth-Order Optimization of Optical Neural Networks

AAAI 2025technical

Optical neural networks (ONNs) have attracted great attention due to their low power consumption and high-speed processing. When training an ONN implemented on a chip with possible fabrication variations, the well-known backpropagation algorithm cannot be executed accurately because the perfect info…

Cited by 0SourcePDFScholar
2025

Natural Perturbations for Black-box Training of Neural Networks by Zeroth-Order Optimization

ICML 2025poster

This paper proposes a novel concept of natural perturbations for black-box training of neural networks by zeroth-order optimization. When a neural network is implemented directly in hardware, training its parameters by backpropagation ends up with an inaccurate result due to the lack of detailed int…

Cited by 0SourcePDFScholar
2022

Multi-Frame Full-Rank Spatial Covariance Analysis for Underdetermined BSS in Reverberant Environments

ICASSP 2022accepted

Full-rank spatial covariance analysis (FCA) is a blind source separation (BSS) method, and can be applied to underdetermined cases where the sources outnumber the microphones. This paper proposes a new extension of FCA, aiming to improve BSS performance for mixtures in which the length of reverberat…

Cited by 0SourceScholar
2021

Asynchronous Decentralized Optimization With Implicit Stochastic Variance Reduction

ICML 2021spotlight

A novel asynchronous decentralized optimization method that follows Stochastic Variance Reduction (SVR) is proposed. Average consensus algorithms, such as Decentralized Stochastic Gradient Descent (DSGD), facilitate distributed training of machine learning models. However, the gradient will drift wi…

2021

Blind and Neural Network-Guided Convolutional Beamformer for Joint Denoising, Dereverberation, and Source Separation

ICASSP 2021accepted

This paper proposes an approach for optimizing a Convolutional BeamFormer (CBF) that can jointly perform denoising (DN), dereverberation (DR), and source separation (SS). First, we develop a blind CBF optimization algorithm that requires no prior information on the sources or the room acoustics, by…

Cited by 0SourceScholar
2020

A Frequency-Domain BSS Method Based on ℓ1 Norm, Unitary Constraint, and Cayley Transform

ICASSP 2020accepted

We propose a frequency-domain blind source separation method that uses (a) the ℓ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> norm of orthonormal vectors of estimated source signals as a sparsity measure and (b) Cayley transform for optimizin…

Cited by 0SourceScholar
2015

Cross-Domain Matching for Bag-of-Words Data via Kernel Embeddings of Latent Distributions

NeurIPS 2015poster

We propose a kernel-based method for finding matching between instances across different domains, such as multilingual documents and images with annotations. Each instance is assumed to be represented as a multiset of features, e.g., a bag-of-words representation for documents. The major difficulty…

Cited by 12SourcePDFScholar
2015

Efficient multichannel nonnegative matrix factorization exploiting rank-1 spatial model

ICASSP 2015accepted

This paper proposes a new efficient multichannel nonnegative matrix factorization (NMF) method. Recently, multichannel NMF (MNMF) has been proposed as a means of solving the blind source separation problem. This method estimates a mixing system of sources and attempts to separate them in a blind fas…

Cited by 0SourceScholar