Direction-of-Arrival (DOA) estimation of incoming narrowband waves using signals spatially sampled by spatially distributed sensors is one of the fundamental and classical problems of array signal processing. In this article, we review the fundamentals of DOA estimation, including signal modeling and the MUltiple SIgnal Classification (MUSIC) algorithm, and introduce some recent topics, such as the MUSIC algorithm via the Khatri-Rao (KR) product subspace and the MUSIC algorithm using the idea of a multiple measurement vector (MMV) problem in the context of compressed sensing.

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The objective of the study is to easily and briefly describe algebraic error-correcting codes and their techniques. The necessary knowledge to read the paper is assumed mainly within elementary mathematics except for a part and we discuss them along with various examples. This is because the easiest method of understanding the algebraic coding theory is considered to be the calculation of their numerical examples. We start our description of the theory of linear feedback shift registers (LFSR) which are regarded to be a class of recurrence relations. Then, we treat Reed-Solomon codes, discrete Fourier transforms, and the basics of Gr¨obner bases in this paper.

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In this paper, I forecast the next-generation vehicle five to twenty years after, on the basis of the trend of ITS, the changes of in social society situations and vehicle technology, for example. In addition, I describe the arrangement from a user viewpoint and the future issues against mobility. Furthermore, on the basis of these forecast and descriptions, I explain future issues of ITS and mobility as well as give my personal opinion.

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Although ultrasonic energy is relatively thin at the molecular level, it can cause irreversible changes to biological tissue after it accumulates as heat. Thermal treatment using high-intensity focused ultrasound (HIFU) is one of its applications. The scientific and engineering basis of this application is explained in this article. Because the ratio of biological tissue to convert ultrasonic energy to heat, i.e. ultrasonic absorption, is approximately proportional to ultrasonic frequency, this frequency must be chosen in accordance with the propagation distance in tissue to the target tissue to be treated. By choosing the HIFU exposure duration to be within the time in which no significant heat conduction takes place, the spatial selectivity of focused ultrasound can be utilized for medical treatment. To suppress the overheating of the intervening healthy tissue, a long pause between consecutive HIFU exposures is necessary to allow blood perfusion to cool the intervening tissue: this significantly lowers the throughput of HIFU treatment. These are explained in terms of the basic principles whenever possible. Imaging methods for use in HIFU and for monitoring the treatment as well as research to enhance the treatment throughput are also explained.

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IC chips become dubious in authenticity – the identity, birth origin and operation correctness may be faked or altered somewhere in the international specializations of IC chip manufacturing and packaging. The warning is directed not at semiconductor businesses but also at every hardware product development. This article gives an overviews of the counterfeiting, tampering and falsification of IC chips and an explorations of preventive as well as proactive measures against them.

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Bitcoin is a decentralized virtual currency based on P2P technology. It enables the unique distribution of electronic value from one person to another without the existence of a centralized issuer. Virtual currency circulates in an open-looped system as if it were real money, whereas existing electronic money circulates in a closed-looped system. The decentralization issue of virtual currency raises a question concerning the seigniorage profit, which ought to be under state monopoly. In this article, we explain why the seigniorage profit is attributable to the state for what reason currency issuance should be decentralized. We also discuss the ideal public policy for virtual currency in order for decentralized currency to achieve justice as fairness.

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