During the period 1985-2022, I developed high-frequency circuits for mobile communications, especially radio frequency integrated circuits (RFICs) that integrate transceiver functions and power amplifiers (PAs) that amplify the transmitted signal, at various companies (Hitachi, Ltd., Renesas Electronics Corporation, and Murata Manufacturing Co., Ltd.). Looking back on the history of my own development, it can be divided into three periods : the early period when I was searching for applications until the emergence of cell phones as a killer application, the mid-period when I was developing RFIC and PA modules mainly for second-generation cell phones, and the late period when I was developing PA modules for smartphones. In the latter half of this period, I was developing PA modules for smart phones. In this paper, I describe the early stage of development during which I was searching for applications as my starting point, and how it led to the later stage of development.

In this paper, the latest advancements in source separation and target speech extraction technologies are reviewed. The former technology separates individual sounds from an acoustic signal recorded with multiple voices and other sounds, and the latter one extracts only the speech of the desired speaker. These technologies make speech more understandable for humans and contribute to improving downstream speech applications. Two important approaches are discussed: signal-model-based and neural-network-based methods. Then detailed explanations of representative techniques in the approaches, blind source separation in reverberant environments, and target speech extraction based on voice features are provided. Finally, the future prospects of this technological field are discussed.

In this paper, we discuss how second language (L2) learners process prosody, emphasizing their ability to integrate multiple linguistic cues during comprehension. In L2 comprehension, learners need to adapt to their linguistic environment and anticipate likely continuations of utterances by interpreting prosodic patterns. Understanding these processes is crucial to identifying the mechanisms underlying L2 prosodic acquisition and processing. Our discussion begins with an overview of key models that explain how L2 learners acquire prosody in the target language. We then consider how prosodic cues influence L2 comprehension and highlight specific challenges faced by learners. By focusing on incremental and anticipatory processing, we review research findings that clarify the cognitive and perceptual mechanisms involved in L2 prosodic processing. Finally, we present empirical studies to illustrate qualitative differences between native speakers and L2 learners in how they integrate prosodic cues with other linguistic information and adapt to both conventional and atypical prosodic patterns.

Disasters related to expressways include heavy rain, earthquakes, tunnel fires, and heavy snow. In this paper, I will explain the use of ICT in the maintenance, management, and operation of expressways, which are social infrastructure necessary for a safe and secure life. First, I will summarize the current state of response to tunnel fires and consider the efforts that will be required in the future. Next, I will summarize various snow and ice work in preparation for heavy snow disasters. I will also explain safety measures using ICT for customers who travel on expressways and workers who perform snow removal work.

In computing system environments that realize advanced artificial intelligence (AI) and IoT, remarkably high computing power is required. To achieve this requirement, reconfigurable (adaptive) devices such as FPGAs are becoming attractive. The Adaptive Computing Research Initiative (ACRi) aims to develop high-performance adaptive computing systems to develop an FPGA design platform. The initiative is working on research themes such as the development of FPGA accelerators to speed up AI processing, the development of FPGA accelerators and FPGA systems for IoT, and the development of an FPGA design platform. In addition, as an outreach activity for research results and the typical FPGA development environment, the initiative is working on a project to popularize FPGA-related technologies, including the systems that have been developed. In this article, we will explain the above efforts and the way to utilize adaptive devices in VLSI design.