The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Nobutaka Ono - One of the best experts on this subject based on the ideXlab platform.
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independent low rank matrix analysis based on time variant sub gaussian Source Model for determined blind Source separation
IEEE Transactions on Audio Speech and Language Processing, 2020Co-Authors: Shinichi Mogami, Norihiro Takamune, Daichi Kitamura, Hiroshi Saruwatari, Yu Takahashi, Kazunobu Kondo, Nobutaka OnoAbstract:Independent low-rank matrix analysis (ILRMA) is a fast and stable method of blind audio Source separation. Conventional ILRMAs assume time-variant (super-)Gaussian Source Models, which can only represent signals that follow a super-Gaussian distribution. In this article, we focus on ILRMA based on a generalized Gaussian distribution (GGD-ILRMA) and propose a new type of GGD-ILRMA that adopts a time-variant sub-Gaussian distribution for the Source Model. We propose a new update scheme called generalized iterative projection for homogeneous Source Models (GIP-HSM) and obtain a convergence-guaranteed update rule for demixing spatial parameters by combining the GIP-HSM scheme and the majorization-minimization (MM) algorithm. Furthermore, a new extension of the MM algorithm is proposed for the convergence acceleration by applying the majorization-equalization algorithm to a multivariate case. In the experimental evaluation, we show the versatility of the proposed method, i.e., the proposed time-variant sub-Gaussian Source Model can be applied to various types of Source signal.
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independent low rank matrix analysis based on time variant sub gaussian Source Model
arXiv: Audio and Speech Processing, 2018Co-Authors: Shinichi Mogami, Norihiro Takamune, Daichi Kitamura, Hiroshi Saruwatari, Yu Takahashi, Kazunobu Kondo, Hiroaki Nakajima, Nobutaka OnoAbstract:Independent low-rank matrix analysis (ILRMA) is a fast and stable method for blind audio Source separation. Conventional ILRMAs assume time-variant (super-)Gaussian Source Models, which can only represent signals that follow a super-Gaussian distribution. In this paper, we focus on ILRMA based on a generalized Gaussian distribution (GGD-ILRMA) and propose a new type of GGD-ILRMA that adopts a time-variant sub-Gaussian distribution for the Source Model. By using a new update scheme called generalized iterative projection for homogeneous Source Models, we obtain a convergence-guaranteed update rule for demixing spatial parameters. In the experimental evaluation, we show the versatility of the proposed method, i.e., the proposed time-variant sub-Gaussian Source Model can be applied to various types of Source signal.
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auxiliary function based independent vector analysis with power of vector norm type weighting functions
Asia-Pacific Signal and Information Processing Association Annual Summit and Conference, 2012Co-Authors: Nobutaka OnoAbstract:In this paper, we present an auxiliary-function-based independent vector analysis (AuxIVA) based on the Generalized super Gaussian Source Model or Gaussian Source Model with time-varying variance. AuxIVA is a convergence-guaranteed iterative algorithm for independent vector analysis (IVA) with a spherical and super Gaussian Source Model, and the Source Model can be characterized by a weighting function. We show that both of the generalized Gaussian Source Models with the shape parameter 0 < β ≤ 2 and the Gaussian Source Model with time-varying variance unifiedly yield a power of vector-norm type weighting functions. A scaling and a clipping technique for numerical stability are discussed. The dependency of the separation performance on the Source Model is also investigated.
Gerhard Kramer - One of the best experts on this subject based on the ideXlab platform.
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on achieving a positive rate in the Source Model key agreement problem
International Symposium on Information Theory, 2018Co-Authors: Amin Gohari, Onur Gunlu, Gerhard KramerAbstract:The two-party key agreement problem with public discussion, known as the Source Model problem, is considered for an erasure Model for Eve's side information. By relating the key agreement problem to hypothesis testing, a new coding scheme is developed that yields an upper bound on the maximum erasure probability for which the secret-key (SK) capacity is zero. The bound is shown to be tight when Alice's or Bob's Source is binary, and this shows that the new code achieves larger SK rates than the best known coding scheme. A full version of this paper with extensions to general Models for Eve's side information is available in [1].
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on achieving a positive rate in the Source Model key agreement problem
2017Co-Authors: Amin Gohari, Onur Gunlu, Gerhard KramerAbstract:The two-party key agreement problem via public discussion, known as the Source Model problem, is considered. Assuming an erasure Model for Eve's side information, the maximum erasure probability for which the secret-key capacity is zero is studied. Our first main contribution is to give a lower and an upper bound on this maximum erasure probability. The lower and upper bounds are shown to match in some special cases, notably when Alice's or Bob's Source is binary. Our second main contribution is to compare our bounds with the best known lower bound for the SK agreement problem and demonstrate, for the first time in the literature, the suboptimality of the best known lower bound.
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coding for positive rate in the Source Model key agreement problem
arXiv: Information Theory, 2017Co-Authors: Amin Gohari, Onur Gunlu, Gerhard KramerAbstract:A two-party key agreement problem with public discussion, known as the Source Model problem, is considered. By relating key agreement to hypothesis testing, a new coding scheme is developed that yields a sufficient condition to achieve a positive secret-key (SK) rate in terms of Renyi divergence. The merits of this coding scheme are illustrated by applying it to an erasure Model for Eve's side information, and by deriving an upper bound on Eve's erasure probabilities for which the SK capacity is zero. This bound strictly improves on the best known single-letter lower bound on the SK capacity. Moreover, the bound is tight when Alice's or Bob's Source is binary, which extends a previous result for a doubly symmetric binary Source. The results motivate a new measure for the correlation between two random variables, which is of independent interest.
S Cable - One of the best experts on this subject based on the ideXlab platform.
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a quadruple magnetic Source Model for arcade flares and x ray arcade formations outside active regions ii dark filament eruption and the associated arcade flare
The Astrophysical Journal, 2001Co-Authors: Shigenobu Hirose, Yutaka Uchida, S Uemura, Tomotaka Yamaguchi, S CableAbstract:A 2.5-dimensional MHD simulation based on the quadruple magnetic Source Model (Uchida et al.) was performed to deal with a dark filament eruption and the associated arcade flare. The numerical results are summarized as follows:
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a quadruple magnetic Source Model for arcade flares and x ray arcade formations outside active regions i dark filament suspension and the magnetic structure in the pre event regions
Publications of the Astronomical Society of Japan, 1999Co-Authors: Yutaka Uchida, Shigenobu Hirose, S Uemura, S Cable, S Morita, M Torii, Tomotaka YamaguchiAbstract:The high-sensitivity, wide dynamic-range observations by the Soft X-ray Telescope (SXT) aboard Yohkoh has enabled us to look into the faint pre-event structures of arcade flares, and of even fainter X-ray arcade formation events outside active regions. What we have found in the pre-event structure of the latter, however, was not a sagged simple (bipolar) arcade, as expected in the classical Model, but a "dual-arcades" type structure in which the inside legs of each "arcade" cross with the other's, landing at the closer part of the domain of the other. Similar features, together with some other features inexplicable in the classical arcade flare Model, were also found in strong arcade flares in active regions seen axis-on at the limb. These features raised a severe problem with the classical "reclosing of the once opened simple arcade" Model(s). In the present paper, we propose interpretations of what we discovered by Yohkoh-SXT by reviving a quadruple Source Model proposed by one of the authors (YU) years ago, pointing out a serious difficulty in the classical Model(s). This Model, based on the quadruple magnetic Sources in the photo sphere, has a "neutral sheet" already in the pre-event phase in the corona above the field polarity-reversal line in the photosphere, and turns out to explain quite nicely the structures of both faint pre-event corona before arcade formation events, and that of arcade flares discovered by Yohkoh-SXT. A dynamic Model of arcade flares and arcade formation events based on this dark filament Model will be discussed in the forthcoming Paper II of this series.
Tomotaka Yamaguchi - One of the best experts on this subject based on the ideXlab platform.
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a quadruple magnetic Source Model for arcade flares and x ray arcade formations outside active regions ii dark filament eruption and the associated arcade flare
The Astrophysical Journal, 2001Co-Authors: Shigenobu Hirose, Yutaka Uchida, S Uemura, Tomotaka Yamaguchi, S CableAbstract:A 2.5-dimensional MHD simulation based on the quadruple magnetic Source Model (Uchida et al.) was performed to deal with a dark filament eruption and the associated arcade flare. The numerical results are summarized as follows:
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a quadruple magnetic Source Model for arcade flares and x ray arcade formations outside active regions i dark filament suspension and the magnetic structure in the pre event regions
Publications of the Astronomical Society of Japan, 1999Co-Authors: Yutaka Uchida, Shigenobu Hirose, S Uemura, S Cable, S Morita, M Torii, Tomotaka YamaguchiAbstract:The high-sensitivity, wide dynamic-range observations by the Soft X-ray Telescope (SXT) aboard Yohkoh has enabled us to look into the faint pre-event structures of arcade flares, and of even fainter X-ray arcade formation events outside active regions. What we have found in the pre-event structure of the latter, however, was not a sagged simple (bipolar) arcade, as expected in the classical Model, but a "dual-arcades" type structure in which the inside legs of each "arcade" cross with the other's, landing at the closer part of the domain of the other. Similar features, together with some other features inexplicable in the classical arcade flare Model, were also found in strong arcade flares in active regions seen axis-on at the limb. These features raised a severe problem with the classical "reclosing of the once opened simple arcade" Model(s). In the present paper, we propose interpretations of what we discovered by Yohkoh-SXT by reviving a quadruple Source Model proposed by one of the authors (YU) years ago, pointing out a serious difficulty in the classical Model(s). This Model, based on the quadruple magnetic Sources in the photo sphere, has a "neutral sheet" already in the pre-event phase in the corona above the field polarity-reversal line in the photosphere, and turns out to explain quite nicely the structures of both faint pre-event corona before arcade formation events, and that of arcade flares discovered by Yohkoh-SXT. A dynamic Model of arcade flares and arcade formation events based on this dark filament Model will be discussed in the forthcoming Paper II of this series.
Shinichi Mogami - One of the best experts on this subject based on the ideXlab platform.
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independent low rank matrix analysis based on time variant sub gaussian Source Model for determined blind Source separation
IEEE Transactions on Audio Speech and Language Processing, 2020Co-Authors: Shinichi Mogami, Norihiro Takamune, Daichi Kitamura, Hiroshi Saruwatari, Yu Takahashi, Kazunobu Kondo, Nobutaka OnoAbstract:Independent low-rank matrix analysis (ILRMA) is a fast and stable method of blind audio Source separation. Conventional ILRMAs assume time-variant (super-)Gaussian Source Models, which can only represent signals that follow a super-Gaussian distribution. In this article, we focus on ILRMA based on a generalized Gaussian distribution (GGD-ILRMA) and propose a new type of GGD-ILRMA that adopts a time-variant sub-Gaussian distribution for the Source Model. We propose a new update scheme called generalized iterative projection for homogeneous Source Models (GIP-HSM) and obtain a convergence-guaranteed update rule for demixing spatial parameters by combining the GIP-HSM scheme and the majorization-minimization (MM) algorithm. Furthermore, a new extension of the MM algorithm is proposed for the convergence acceleration by applying the majorization-equalization algorithm to a multivariate case. In the experimental evaluation, we show the versatility of the proposed method, i.e., the proposed time-variant sub-Gaussian Source Model can be applied to various types of Source signal.
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independent low rank matrix analysis based on time variant sub gaussian Source Model
arXiv: Audio and Speech Processing, 2018Co-Authors: Shinichi Mogami, Norihiro Takamune, Daichi Kitamura, Hiroshi Saruwatari, Yu Takahashi, Kazunobu Kondo, Hiroaki Nakajima, Nobutaka OnoAbstract:Independent low-rank matrix analysis (ILRMA) is a fast and stable method for blind audio Source separation. Conventional ILRMAs assume time-variant (super-)Gaussian Source Models, which can only represent signals that follow a super-Gaussian distribution. In this paper, we focus on ILRMA based on a generalized Gaussian distribution (GGD-ILRMA) and propose a new type of GGD-ILRMA that adopts a time-variant sub-Gaussian distribution for the Source Model. By using a new update scheme called generalized iterative projection for homogeneous Source Models, we obtain a convergence-guaranteed update rule for demixing spatial parameters. In the experimental evaluation, we show the versatility of the proposed method, i.e., the proposed time-variant sub-Gaussian Source Model can be applied to various types of Source signal.
