In communication and recording systems affected by uncertainties in timing or time noise, synchronization errors, such as symbol insertions and deletions, can significantly impair the reliability and efficiency of the system. In this article, we review synchronization error-correcting codes based on probabilistic inference and sparse matrices. We first present a probabilistic channel model of synchronization errors, formalize a decoding problem for the channel as probabilistic inference, and show a belief-propagation decoding algorithm. Then, we review some existing synchronization error-correcting codes.

Fugaku became the world's fastest supercomputer in the TOP500 competition in June 2020. This high-performance record is supported by various state-of-the-art technologies in all development phases, from logic and physical designs to prototype and mass production. For example, in the logic design phase, numbers of complex logics are created to succeed in high-speed floating-point operations ; in the semiconductor implementation phase, high-density customized circuits are used to maximize the performance ; and in the manufacturing phase, new integrated electrical and cooling water supply connectors are developed to install as many CPUs as possible in the rack. To confirm the quality of these technologies, we also applied various verification, test, and validation technologies. In this paper, we introduce the following technologies applied in the Fugaku project ; (1) logic verification technology, which enables us to verify large-scale complex logic in a small-scale verification environment within a short time period, (2) semiconductor test technology used to perform necessary and sufficient fault diagnosis coverage while reducing the area of the test circuit as much as possible, and (3) prototype testing technology used to validate the functions of newly developed high-density components.

The resolution of the image obtained with ultrasound or photoacoustic signals, which are generated by very short and strong pulse light, is inversely proportional to the frequency of the waves. In the field of medicine and biology, the frequency used for imaging is variable between several MHz to GHz range. Thus, the imaging area is from 10-20 cm to micron order. In this article, these imaging technologies, mainly the authors' development are introduced and the future perspective is discussed.

The stool color card for the early detection of biliary atresia has been developed using multispectral images of stools of newborns. The color and its reflectance were measured and analyzed spectrally and used to design the stool color card. The representative texture was selected by medical specialists from color images reproduced using six-band images. The spectral reflectance of the images was replaced and edited in accordance with the result of spectral and chromaticity analysis. Since 2021, the stool color card has been included in the Maternal and Child Health Handbook that is distributed to all pregnant women by their respective local government in accordance with the Maternal and Child Health Law in Japan.

The age of drones flying above urban, mountain, and island areas for applications such as transportation, aerial photography, inspection, agriculture, and disaster mitigation is fast approaching. Wireless technology plays a significant role in operating drones safely, in addition to improved drone technology and unmanned aircraft traffic management (UTM) systems. In this article, we present the techniques of beyond-line-of-sight (BLOS) command and telemetry communications and vehicle-to-vehicle (V2V) communications, which have been developed by NICT. Furthermore, we give a brief introduction to the R & D of a wide-area communication system for drones via a relay using a high-altitude platform station (HAPS), which has been started as one of the technologies to provide “supercoverage” in the coming 6G Era.

Multiple-input multiple-output (MIMO) transmission is a practical frequency-efficient transmission technology that employs multiple transmission and reception antennas to multiplex multiple signals at the same frequency. In this paper, we describe an advanced form of MIMO transmission, in which wireless terminals collaborate with other terminals to expand the equivalent number of antennas and improve the channel capacity. We assume that the recently developed high-speed and low-latency transmission technology in high-frequency bands will be used for collaborative communications among terminals. We explain the relationship among collaboration traffic, spatial correlation, and transmission capacity, and present the results of field experiments conducted in a suburb of Kyoto City.

The popularization of ICT in our society enables us to develop various information systems and cloud services easily. However, it is difficult to completely define the requirements in the field of disaster prevention and mitigation, and research is still underway. The author has been designing, developing, and implementing systems and services with ICT in actual disaster areas using the method of action research. In addition, we have analyzed the actual data obtained by such implementation and extracted new institutional knowledge. In this paper, I introduce our past activities and mention the necessity of “digital disaster prevention” in the next-generation society where DX conversion is promoting.