55 research outputs found
Nonparametric Bayesian Dereverberation of Power Spectrograms Based on Infinite-Order Autoregressive Processes
This paper describes a monaural audio dereverberation method that operates in the power spectrogram domain. The method is robust to different kinds of source signals such as speech or music. Moreover, it requires little manual intervention, including the complexity of room acoustics. The method is based on a non-conjugate Bayesian model of the power spectrogram. It extends the idea of multi-channel linear prediction to the power spectrogram domain, and formulates a model of reverberation as a non-negative, infinite-order autoregressive process. To this end, the power spectrogram is interpreted as a histogram count data, which allows a nonparametric Bayesian model to be used as the prior for the autoregressive process, allowing the effective number of active components to grow, without bound, with the complexity of data. In order to determine the marginal posterior distribution, a convergent algorithm, inspired by the variational Bayes method, is formulated. It employs the minorization-maximization technique to arrive at an iterative, convergent algorithm that approximates the marginal posterior distribution. Both objective and subjective evaluations show advantage over other methods based on the power spectrum. We also apply the method to a music information retrieval task and demonstrate its effectiveness
Loop Copilot: Conducting AI Ensembles for Music Generation and Iterative Editing
Creating music is iterative, requiring varied methods at each stage. However,
existing AI music systems fall short in orchestrating multiple subsystems for
diverse needs. To address this gap, we introduce Loop Copilot, a novel system
that enables users to generate and iteratively refine music through an
interactive, multi-round dialogue interface. The system uses a large language
model to interpret user intentions and select appropriate AI models for task
execution. Each backend model is specialized for a specific task, and their
outputs are aggregated to meet the user's requirements. To ensure musical
coherence, essential attributes are maintained in a centralized table. We
evaluate the effectiveness of the proposed system through semi-structured
interviews and questionnaires, highlighting its utility not only in
facilitating music creation but also its potential for broader applications.Comment: Source code and demo video are available at
\url{https://sites.google.com/view/loop-copilot
Reconfiguration of Time-Respecting Arborescences
An arborescence, which is a directed analogue of a spanning tree in an
undirected graph, is one of the most fundamental combinatorial objects in a
digraph. In this paper, we study arborescences in digraphs from the viewpoint
of combinatorial reconfiguration, which is the field where we study
reachability between two configurations of some combinatorial objects via some
specified operations. Especially, we consider reconfiguration problems for
time-respecting arborescences, which were introduced by Kempe, Kleinberg, and
Kumar. We first prove that if the roots of the initial and target
time-respecting arborescences are the same, then the target arborescence is
always reachable from the initial one and we can find a shortest
reconfiguration sequence in polynomial time. Furthermore, we show if the roots
are not the same, then the target arborescence may not be reachable from the
initial one. On the other hand, we show that we can determine whether the
target arborescence is reachable form the initial one in polynomial time.
Finally, we prove that it is NP-hard to find a shortest reconfiguration
sequence in the case where the roots are not the same. Our results show an
interesting contrast to the previous results for (ordinary) arborescences
reconfiguration problems.Comment: 13 pages, 3 figures, WADS 202
IL-4–Stat6 Signaling Induces Tristetraprolin Expression and Inhibits TNF-α Production in Mast Cells
Increasing evidence has revealed that mast cell–derived tumor necrosis factor α (TNF-α) plays a critical role in a number of inflammatory responses by recruiting inflammatory leukocytes. In this paper, we investigated the regulatory role of interleukin 4 (IL-4) in TNF-α production in mast cells. IL-4 inhibited immunoglobulin E–induced TNF-α production and neutrophil recruitment in the peritoneal cavity in wild-type mice but not in signal transducers and activators of transcription 6 (Stat6)–deficient mice. IL-4 also inhibited TNF-α production in cultured mast cells by a Stat6-dependent mechanism. IL-4–Stat6 signaling induced TNF-α mRNA destabilization in an AU-rich element (ARE)–dependent manner, but did not affect TNF-α promoter activity. Furthermore, IL-4 induced the expression of tristetraprolin (TTP), an RNA-binding protein that promotes decay of ARE-containing mRNA, in mast cells by a Stat6-dependent mechanism, and the depletion of TTP expression by RNA interference prevented IL-4–induced down-regulation of TNF-α production in mast cells. These results suggest that IL-4–Stat6 signaling induces TTP expression and, thus, destabilizes TNF-α mRNA in an ARE-dependent manner
High Excitation Molecular Gas in the Galactic Center Loops; 12CO(J =2-1 and J =3-2) Observations
We have carried out 12CO(J =2-1) and 12CO(J =3-2) observations at spatial
resolutions of 1.0-3.8 pc toward the entirety of loops 1 and 2 and part of loop
3 in the Galactic center with NANTEN2 and ASTE. These new results revealed
detailed distributions of the molecular gas and the line intensity ratio of the
two transitions, R3-2/2-1. In the three loops, R3-2/2-1 is in a range from 0.1
to 2.5 with a peak at ~ 0.7 while that in the disk molecular gas is in a range
from 0.1 to 1.2 with a peak at 0.4. This supports that the loops are more
highly excited than the disk molecular gas. An LVG analysis of three
transitions, 12CO J =3-2 and 2-1 and 13CO J =2-1, toward six positions in loops
1 and 2 shows density and temperature are in a range 102.2 - 104.7 cm-3 and
15-100 K or higher, respectively. Three regions extended by 50-100 pc in the
loops tend to have higher excitation conditions as characterized by R3-2/2-1
greater than 1.2. The highest ratio of 2.5 is found in the most developed foot
points between loops 1 and 2. This is interpreted that the foot points indicate
strongly shocked conditions as inferred from their large linewidths of 50-100
km s-1, confirming the suggestion by Torii et al. (2010b). The other two
regions outside the foot points suggest that the molecular gas is heated up by
some additional heating mechanisms possibly including magnetic reconnection. A
detailed analysis of four foot points have shown a U shape, an L shape or a
mirrored-L shape in the b-v distribution. It is shown that a simple kinematical
model which incorporates global rotation and expansion of the loops is able to
explain these characteristic shapes.Comment: 59 pages, accepted to PAS
Development of precision Wolter mirrors for future solar x-ray observations
Taro Sakao, Satoshi Matsuyama, Ayumi Kime, Takumi Goto, Akihiko Nishihara, Hiroki Nakamori, Kazuto Yamauchi, Yoshiki Kohmura, Akira Miyake, Hirokazu Hashizume, Tadakazu Maezawa, Yoshinori Suematsu, and Noriyuki Narukage "Development of precision Wolter mirrors for future solar x-ray observations", Proc. SPIE 9603, Optics for EUV, X-Ray, and Gamma-Ray Astronomy VII, 96030U (4 September 2015); https://doi.org/10.1117/12.2188905
Development of precision Wolter mirrors for solar x-ray observations
Taro Sakao, Satoshi Matsuyama, Takumi Goto, Jumpei Yamada, Shuhei Yasuda, Kazuto Yamauchi, Yoshiki Kohmura, Ayumi Kime, Akira Miyake, Tadakazu Maezawa, Hirokazu Hashizume, Yoshinori Suematsu, Noriyuki Narukage, and Shin-nosuke Ishikawa "Development of precision Wolter mirrors for solar x-ray observations", Proc. SPIE 10386, Advances in X-Ray/EUV Optics and Components XII, 103860E (23 August 2017); https://doi.org/10.1117/12.2273507
THE NEUTRAL INTERSTELLAR GAS TOWARD SNR W44: CANDIDATES FOR TARGET PROTONS IN HADRONIC γ-RAY PRODUCTION IN A MIDDLE-AGED SUPERNOVA REMNANT
We present an analysis of the interstellar medium (ISM) toward the γ-ray supernova remnant (SNR) W44. We used NANTEN2 12CO(J = 2-1) and 12CO(J = 1-0) data and Arecibo H I data in order to identify the molecular and atomic gas in the SNR. We confirmed that the molecular gas is located in the SNR shell with a primary peak toward the eastern edge of the shell. We newly identified high-excitation molecular gas along the eastern shell of the SNR in addition to the high-excitation broad gas previously observed inside the shell; the line intensity ratio between the 12CO(J = 2-1) and 12CO(J = 1-0) transitions in these regions is greater than ~1.0, suggesting a kinetic temperature of 30 K or higher, which is most likely due to heating by shock interaction. By comparing the ISM with γ-rays, we find that target protons of hadronic origin are dominated by molecular protons of average density around 200 cm–3, where the possible contribution of atomic protons is 10% or less. This average density is consistent with the recent discovery of the low-energy γ-rays suppressed in 50 MeV-10 GeV as observed with AGILE and Fermi. The γ-ray spectrum differs from place to place in the SNR, suggesting that the cosmic-ray (CR) proton spectrum significantly changes within the middle-aged SNR perhaps due to the energy-dependent escape of CR protons from the acceleration site. We finally derive a total CR proton energy of ~1049 erg, consistent with the SN origin of the majority of the CRs in the Galaxy
- …