Institution profile

Shizuoka University

Academic institutionasia · jp
Official website
Research library30linked papers
Opportunities0open roles
Selected work

Representative Papers

Face Re-morphing: Differential Morphing Attack Detection via Feature-Space Similarity Changes

Aug 13, 2026

This study addresses the performance limitations of existing face morphing attack detection methods that rely predominantly on static features. We propose a novel detection framework leveraging similarity variations induced by re-morphing operations. Specifically, this work pioneers the utilization of feature space response discrepancies caused by secondary morphing as complementary discriminative cues, achieving precise identification through image re-morphing generation and cosine similarity analysis. Extensive experiments demonstrate that the proposed method exhibits robust generalization across multiple datasets and models, with particularly superior performance on the AMSL and FEI Morph datasets. By effectively overcoming the bottlenecks inherent in traditional static detection approaches, this research establishes a new paradigm for defending against face morphing attacks.

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XSA-MAD: Cross-modal Semantic Alignment for Morphing Attack Detection

Aug 13, 2026

This study addresses the limited generalizability of existing image manipulation detection methods by proposing a CLIP-based multimodal framework. The approach innovatively decouples manipulation into four interpretable attributes—identity, geometry, texture, and consistency—and constructs a unified semantic representation through progressive cross-modal alignment, enabling generation-agnostic, concept-level discrepancy modeling. By effectively capturing generation-invariant features, the method demonstrates strong generalization on the MAD22 and MorDIFF datasets, achieving an Equal Error Rate (EER) as low as 2.92% for GAN manipulations. Furthermore, it consistently outperforms state-of-the-art approaches in high-fidelity attack scenarios, significantly enhancing detection robustness against diverse and evolving synthetic media threats.

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Cross-country structure of a sexual contact network derived from a commercial-sex review platform

Jul 24, 2026

Constrained by technological, ethical, and privacy limitations, large-scale sexual contact networks remain largely unobservable, impeding understanding of the cross-regional transmission dynamics of sexually transmitted infections. This study leverages over 1.43 million client–sex worker reviews from The Erotic Review platform (1999–2024) to construct, for the first time, a multinational bipartite network. Applying complex network methodologies—including connected component identification, small-world analysis, and degree correlation—we uncover its macroscopic connectivity structure. The network exhibits small-world properties and contains a giant connected component. A small number of high-frequency cross-border clients act as spatial bridges, while long-term users serve as temporal bridges, both significantly enhancing network cohesion. Interactions involving transgender female sex workers are highly concentrated among these highly active cross-border clients, revealing pronounced structural centralization.

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Group invariance of $f$-divergences and the Fisher--Rao distance

Jun 24, 2026

This study investigates the invariance properties of distributional divergence measures within group-symmetric statistical models. By endowing both the sample and parameter spaces with a group action and assuming that density functions transform according to a multiplier representation, the authors integrate tools from group representation theory, transformation models, $f$-divergence analysis, and Fisher–Rao information geometry. They establish that all $f$-divergences and the Fisher–Rao distance are invariant under the induced group action. The key contribution lies in showing that such invariant divergences reduce to functions depending solely on the maximal invariants of the parameter pair. This framework is successfully extended to multivariate location-scale families, where the invariant geometric structure of the parameter space is characterized via double coset decompositions.

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Recent publications

Latest Papers

Face Re-morphing: Differential Morphing Attack Detection via Feature-Space Similarity Changes

Aug 13, 2026

This study addresses the performance limitations of existing face morphing attack detection methods that rely predominantly on static features. We propose a novel detection framework leveraging similarity variations induced by re-morphing operations. Specifically, this work pioneers the utilization of feature space response discrepancies caused by secondary morphing as complementary discriminative cues, achieving precise identification through image re-morphing generation and cosine similarity analysis. Extensive experiments demonstrate that the proposed method exhibits robust generalization across multiple datasets and models, with particularly superior performance on the AMSL and FEI Morph datasets. By effectively overcoming the bottlenecks inherent in traditional static detection approaches, this research establishes a new paradigm for defending against face morphing attacks.

0 citationsRead paper

XSA-MAD: Cross-modal Semantic Alignment for Morphing Attack Detection

Aug 13, 2026

This study addresses the limited generalizability of existing image manipulation detection methods by proposing a CLIP-based multimodal framework. The approach innovatively decouples manipulation into four interpretable attributes—identity, geometry, texture, and consistency—and constructs a unified semantic representation through progressive cross-modal alignment, enabling generation-agnostic, concept-level discrepancy modeling. By effectively capturing generation-invariant features, the method demonstrates strong generalization on the MAD22 and MorDIFF datasets, achieving an Equal Error Rate (EER) as low as 2.92% for GAN manipulations. Furthermore, it consistently outperforms state-of-the-art approaches in high-fidelity attack scenarios, significantly enhancing detection robustness against diverse and evolving synthetic media threats.

0 citationsRead paper

Cross-country structure of a sexual contact network derived from a commercial-sex review platform

Jul 24, 2026

Constrained by technological, ethical, and privacy limitations, large-scale sexual contact networks remain largely unobservable, impeding understanding of the cross-regional transmission dynamics of sexually transmitted infections. This study leverages over 1.43 million client–sex worker reviews from The Erotic Review platform (1999–2024) to construct, for the first time, a multinational bipartite network. Applying complex network methodologies—including connected component identification, small-world analysis, and degree correlation—we uncover its macroscopic connectivity structure. The network exhibits small-world properties and contains a giant connected component. A small number of high-frequency cross-border clients act as spatial bridges, while long-term users serve as temporal bridges, both significantly enhancing network cohesion. Interactions involving transgender female sex workers are highly concentrated among these highly active cross-border clients, revealing pronounced structural centralization.

0 citationsRead paper

Group invariance of $f$-divergences and the Fisher--Rao distance

Jun 24, 2026

This study investigates the invariance properties of distributional divergence measures within group-symmetric statistical models. By endowing both the sample and parameter spaces with a group action and assuming that density functions transform according to a multiplier representation, the authors integrate tools from group representation theory, transformation models, $f$-divergence analysis, and Fisher–Rao information geometry. They establish that all $f$-divergences and the Fisher–Rao distance are invariant under the induced group action. The key contribution lies in showing that such invariant divergences reduce to functions depending solely on the maximal invariants of the parameter pair. This framework is successfully extended to multivariate location-scale families, where the invariant geometric structure of the parameter space is characterized via double coset decompositions.

0 citationsRead paper