Since the basis of Hölder's inequality was found by mathematicians, i.e., independently by Rogers in 1888 and Hölder in 1889, the inequality has been frequently utilized as a basic inequality in mathematical analysis such as functional analysis. However, surprisingly, no physical interpretation of the inequality seems to be known until 2014. In this article, as a sequel to “Nonlinear Problems and Hölder's Inequality” (Jan. 2016), I show that the inequality leads to an elegant solution to recent nonlinear problems and also inspires them.

In recent years, there has been increasing attention worldwide focused on rapidly evolving autonomous driving and driving support technologies. These technologies are applications of intelligent transport systems (ITS). The purpose of ITS is to solve traffic problems in society by improving safety, smoothness, comfort, and environmental performance using advanced information communication technology. In this paper, I will purline the main research related to ITS wireless communication systems, then describe the research trends in autonomous driving and driving support. After that, I will introduce a vehicle collision avoidance support system (VCASS) and a pedestrian-vehicular collision avoidance support system (P-VCASS) thar have recently been developed.

As airborne sound is density variation, it can be measured optically by detecting the refractive index of air, enabling us to observe a sound field not tractable by a microphone. In this paper, the history and principle of the optical measurement of audible sound are presented together with the methodologies (laser Doppler vibrometry and high-speed polarized interferometry). Some examples of optically measured sound fields are also shown.

In this manuscript, by reviewing the mathematical theory of binary state systems, some crucial concepts in the theory, like minimal cut and minimal path vectors, a modular decomposition and stochastic wear processes, are generalized to the case of a multi-state system with totally ordered state spaces. Furthermore, we show the applicability of a model of a multistate system to the reliability analysis of a network.

After surveying English learner corpora with a focus on the ICLE/LINDSEI and the ICNALE, this paper explains analytical methods and major findings of the previous learner corpus studies. It also reports some of the features seen in L2 English writing by Japanese learners such as the type of the vocabulary used in the essays, overused words, grammatical accuracy, and overall ratings, which have been revealed by the analysis of the ICNALE.

This manuscript introduces a method of power converter designs that applies a nonlinear analysis technique. Recently, the development of next-generation semiconductor devices, such as silicon carbide (SiC) and gallium nitride (GaN), has opened the way to new technological innovations, namely, high-frequency, high-efficiency, and small-scale power converters. To achieve converter designs using these devices, a new analysis-and-design approach that provides high-accuracy design values is required. On the other hand, switching power converters are regarded as nonlinear dynamical systems. From this viewpoint, it is possible to dramatically improve the converter-design efficiency by applying the nonlinear analysis technique to converter designs. Through concrete examples of converter designs using the proposed design technique, we show the effecriveness and applicability of the nonlinear analysis technique.

When a disaster strikes, many people make calls to loved ones resulting in congested networks. Many countermeasure technologies against the congestion of networks during disasters have been proposed to improve that people can inform loved ones of their safety. We classify the technologies from the view point of supply and demand because an imbalance between supply and demand results in congestion. We introduce countermeasure technologies against disaster congestion on a voice network from the view points of preserving and increasing voice supply, geometrically distributing voice demand, alternating voice demand with other services, and reducing voice demand.