Robust estimation of directions-of-arrival in diffuse noise based on matrix-space sparsity

We consider the estimation of the Directions-Of-Arrival (DOA) of target signals in diffuse noise. The state-of-the-art MUltiple SIgnal Classification (MUSIC) algorithm necessitates accurate identification of the signal subspace. In diffuse noise, however, it is difficult to identify it directly from the observed spatial covariance matrix. In our approach, we estimate the target spatial covariance matrix, so that we can identify the orthogonal complement of the signal subspace as its null space. We present a unified framework for modeling noise covariance in a matrix space, which generalizes four state-of-the-art diffuse noise models. We propose two alternative algorithms for estimating the target spatial covariance matrix, namely Low-rank Matrix Completion (LMC) and Trace Norm Minimization (TNM). These rely on denoising of the observed spatial covariance matrix via orthogonal projection onto the orthogonal complement of the noise matrix subspace. The missing component lying in the noise matrix subspace is then completed by exploiting the low-rankness of the target spatial covariance matrix. Large-scale experiments with real-world noise show that TNM with a certain noise model outperforms conventional MUSIC based on Generalized EigenValue Decomposition (GEVD) by 5% in terms of the precision averaged over the dataset

Audio Signal Enhancement with Learning from Positive and Unlabelled Data

Supervised learning is a mainstream approach to audio signal enhancement (SE) and requires parallel training data consisting of both noisy signals and the corresponding clean signals. Such data can only be synthesised and are mismatched with real data, which can result in poor performance on real data. Moreover, clean signals may be inaccessible in certain scenarios, which renders this conventional approach infeasible. Here we explore SE using non-parallel training data consisting of noisy signals and noise, which can be easily recorded. We define the positive (P) and the negative (N) classes as signal inactivity and activity, respectively. We observe that the spectrogram patches of noise clips can be used as P data and those of noisy signal clips as unlabelled data. Thus, learning from positive and unlabelled data enables a convolutional neural network to learn to classify each spectrogram patch as P or N to enable SE.Comment: Accepted to ICASSP202

Community based Asian Agrifuture: how it can be achieved: Agrifuturo asiático de base comunitária: como pode ser alcançado

Asia is one of the most productive agricultural regions in the world, however the quality control of agricultural food products should be severely and strictly managed from the view point of food security and safety due to the increase of food feeding demand to cover the drastic and rapidly increase of world human population in recent years. We humans are facing two big global issues of energy and environment. Good solution finding is still under the efforts making on building a sustainable society, however no optimal solution has yet been found. Needless to say the special attention should be paid not to jeopardize the natural environment any more for stopping the global warming. Given the world's population, which is growing rapidly by 80 million people annually, it is easy to guess that food issues could become a major issue sooner or later.  It is natural for us humans to be ready to prepare and address some message immediately if we know what is coming now around us. In this paper the current status of Asian agriculture in the world is overviewed first, then the Asian agrifuture is discussed and proposed from the community based viewpoint how it should / can be promoted and achieved

Conformational studies of mitochondrial DNA

Ring DNA from rat liver mitochondria has been examined by circular dichroism (CD) in the region of the 225 to 320 m/~ and the followings have been clarified. The ring DNA gives a CD spectral curve somewhat different from linear DNA from nuclei, showing a big positive peak at 266 m/~ and a small negative band at 243 m!~. That is, the positive CD band of ring DNA shifted by about 7 m/~ to the shorter wavelength side from the band of the ordinary nuclear DNA, 273 m!~. Negative band appeared at the same region as that of linear DNA but reduced in depth. Heat denaturation of the ring DNA induced a red shift of the positive band, by about 4 mp., but no change in negative band. From these experimental results it has been concluded that the ring DNA has highly twisted conformation and high in G.C contents, both of which are responsible for the blue shift of the CD spectrum.</p

Hyper Low-cost Ultimate Rice Mechanization System : Sistema de Mecanização do Arroz Hyper Low-cost Ultimate

About 480 million tons of rice (milled rice base) are produced annually in the world. It is one of the cereals with a low trade rate for its production. In Asia, more than 90% of the world's production is produced. The top 10 countries in rice production are all Asian countries. The main operation of rice cultivation consists of planting, management while rice growing (weed &amp; pest control, water management), harvesting, and post-harvest processing. In addition to infrastructure development such as irrigation and drainage system through field reclamation, the development of chemical fertilizers, herbicides, and pesticides contributed to labor saving. However, the introduction of the combine harvester, which can significantly save labor and simplify the harvesting operation, is one of the required parts of the technological innovation. In this paper, one direction is shown to realize hyper-low cost of rice cultivation system through these technological innovations, demand and consumption increase of rice, and open up new markets as a response to the future food crisis

Physical analysis of the energy transducing reaction in mitochondria

As is generally known, the energy transducing reaction in mitochondria is of highly complicated one. Free energy produced by transferring electrons from substrate to oxygen, where many dehydrogenases and respiratory chain of mitochondria are concerned, is transduced to ATP formation or utilized for the ion accmulation reaction, synthesis of various substances, reversal electron transport and the mechanochemical changes of mitochondria. The mechanism of these energy trasducing reactions which is supposed to be closely related with each other, has not yet been clarified. The authors tried to solve these biological energy transducing mechnism by applying physical circuit theory in electronics and elucidate that the energy transduction occurring in mitochondria can be explained theoretically. And some unknown but possible reaction have been postulated from such a physical consideration.</p