Takuya Higuchi

Learn More
This paper considers acoustic beamforming for noise robust automatic speech recognition (ASR). A beamformer attenuates background noise by enhancing sound components coming from a direction specified by a steering vector. Hence, accurate steering vector estimation is paramount for successful noise reduction. Recently, a beamforming approach was proposed(More)
This paper deals with the problem of the underdetermined blind separation and tracking of moving sources. In practical situations, sound sources such as human speakers can move freely and so blind separation algorithms must be designed to track the temporal changes of the impulse responses. We propose solving this problem through the posterior inference of(More)
This paper presents a master-slave type remote ultrasound diagnostic system. In the system, the motion of the master manipulator is controlled by a medical doctor and is reproduced by a slave manipulator carrying an ultrasound probe. The contact force between the probe and a patient is fed back to the master manipulator. High-rigidity was achieved by(More)
This paper proposes to introduce a new model called “the multichannel factorial hidden Markov Model (MFHMM)” for underdetermined blind signal separation (BSS). For monaural source separation, one successful approach involves applying nonnegative matrix factorization (NMF) to the magnitude spectrogram of a mixture signal, interpreted as a non-negative(More)
This paper proposes a unified approach for jointly solving underdetermined source separation, audio event detection and dereverberation of convolutive mixtures. For monaural source separation, one successful approach involves applying non-negative matrix factorization (NMF) to the magnitude spectrogram of a mixture signal, interpreted as a non-negative(More)
This paper proposes a novel method for simultaneously solving the problems of underdetermined blind source separation (BSS), source activity detection, dereverberation and direction-of-arrival (DOA) estimation by introducing an extension of the "multichannel factorial hidden Markov model (MFH-MM)." The MFHMM is an extension of the multichannel non-negative(More)
To determine a thermotolerant fungus strain for decolorization of alcohol distillery wastewater (ADW), 38 fungus strains were studied. Capacity for ligninolytic enzyme production was examined at 35 and 43C on agar media containing 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) and MnCl2. At 43°C, four Pycnoporus coccineus strains showed a higher(More)
Mechanisms of high-harmonic generation from crystals are described by treating the electric field of a laser as a quasistatic strong field. Under the quasistatic electric field, electrons in periodic potentials form dressed states, known as Wannier-Stark states. The energy differences between the dressed states determine the frequencies of the radiation.(More)
Application of coherent light-matter interactions has recently been extended to the ultrafast control of magnetization. An important but unrealized technique is the manipulation of magnetization vector motion to make it follow an arbitrarily designed multidimensional trajectory. Here we demonstrate a full manipulation of two-dimensional magnetic(More)