Electronics and Communications in Japan最新文献

A method using electromyograms to estimate muscle fatigue associated with exercise has been proposed. Muscles can be classified into three types: fast, intermediate, and slow, each of which being activated by physiological metabolic mechanisms that correlate with fatigue. The percentage of muscle fibers in use, which correlates with muscle fatigue, can thus be calculated using frequency analysis. In some participants, this muscle fatigue analysis method failed because actual muscle fatigue did not correlate with percentage of muscle fibers used. Assuming that this phenomenon was due to the characteristics of the subcutaneous fatty tissues between the muscle and skin surface, we attempted to cluster the participants based on their physical characteristics, construct a correction model using physical characteristics as explanatory variables within the clusters, and correct the percentage of muscle fibers used. Consequently, the muscle fatigue in all seven participants, which initially deviated from the ratio of muscle fibers used, was adjusted to align with the expected pattern, thereby enhancing the validity of the muscle fatigue analysis.

In this study, as part of a broader investigation of micro-paper-based analytical devices (microPADs), we verified whether it was possible to measure the electrical resistivity of human blood samples using paper-based chips designed for electrical resistivity measurement. We also aimed to investigate the correlation between electrical resistivity and whole blood viscosity, the latter being calculated from the hematocrit value of blood and the total protein value of serum.

This study introduces an automated enzyme-linked immunosorbent assay (ELISA) system employing a novel dip methodology. Unlike traditional ELISA, which requires complex liquid handling, this approach keeps samples and reagents stationary while immersing antibody-coated reaction fields sequentially. This design eliminates pumps and tubing, reducing maintenance, reagent waste, and overall costs. The system, controlled via a microcontroller and web-based interface, demonstrated accurate and efficient C-reactive protein analysis in human serum. With reduced reagent volumes, lower operational costs, and simplified handling, this system offers significant potential for point-of-care testing, telemedicine, and broader next-generation healthcare applications.

This study proposes a method for change detection by extracting small image pairs from recorded video pairs in patrol inspections of oil plants using a mobile robot equipped with a camera. While change detection methods often perform well in controlled laboratory environments, their performance tends to degrade in plant environments. This is because, in plant environments, the regions of change caused by anomalies within the images are often small, and the environments are structurally complex. In this study, to address this issue, we adopt an approach that extracts small image pairs from the target and reference images for change detection. Additionally, we develop a method for extracting small image pairs that considers the consistency of three-dimensional coordinates based on multi-view stereo. As a result, the proposed method achieved high-precision change detection, demonstrating its potential for application in patrol inspections of oil plants using a mobile robot.

In recent years, large-scale wireless multi-hop networks have been established for smart cities. These network systems collect various data from hundreds of nodes. The IPv6 Routing Protocol for Low-Power and Lossy Networks (RPL) is widely used for building large-scale wireless multi-hop networks. However, previous studies have pointed out that the routing overhead of RPL is significantly high. With an increase in nodes, there is a tendency for the overhead of control messages to rise, which may lead to a decrease in data collection rates due to radio interference between nodes. Moreover, since the radio propagation characteristics in real environments are not uniform, so there are concerns that in poor radio conditions, the retransmission of control messages could locally increase traffic load. To address this issue and allow for flexible adjustment of RPL's routing overhead, we propose to run RPL over Time Division Multiple Access (TDMA) based access control scheme. To evaluate the effectiveness of this approach, we conducted field experiments of a large-scale wireless multi-hop network and report the results in this paper.

In this paper, we propose a classification method for “kawaii” images. Conventional image classification methods, such as CNN (Convolutional Neural Network) and SVM (Support Vector Machine), can classify ordinary images, such as faces, with high accuracy, but they are insufficient for classifying images that are vaguely expressed without a “kawaii” explicit indicator. Through experiments, we propose a suitable method for classifying “kawaii” images by extracting latent color, shape, and other features of “kawaii” images using feature filters, quantitatively representing them, and then comparing classification accuracy using various classifiers based on machine learning techniques. In the experiments, the color, SIFT(Scale Invariant Feature Transform), and line features of the images are extracted using filters and compared using NN (Neural Network), Random Forest, AdaBoost, and SVM. The results show the effectiveness of the proposed feature filters and the suitability of Random Forest as a classifier, and thus an effective method for classification of “kawaii” images.

The magneto-optical (MO) interferences in optical cavities consisting of magnetic stacked films were theoretically analyzed for chemical and biological sensing applications. The MO cavity systems indicated large MO enhancements and sharp responses to the changes in the environmental refractive index. The resolution of refractive index was approximately seven times higher than that of conventional surface plasmon sensors.

This paper presents a design process of a bandpass filter (BPF) with a dielectric-tube supported metal rod transmission line (DTM line). First, the equivalent circuit was shown, and the outline of the design was presented. Next, each dimension was designed using HFSS as electromagnetic field simulator, and an ideal characteristic with the BPF was confirmed. Finally, the prototype and the measured result were presented. The prototype BPF achieved an insertion loss of 1.7 dB at 81 GHz with a fractional bandwidth of 2.4%. In addition, the result was compared with those of BPFs with other transmission lines, and it was shown that the prototype BPF had higher performance than BPFs with the lines that used printed substrates at the same frequency bands.

The isolation characteristics between the antennas of transmission and reception are important for signal quality. In this paper, we propose a small dual-polarized antenna with dual vertical split-ring resonators and differential feeding. This novel antenna is based on artificial magnetic conductors (AMCs) modified to radiate directly. A high isolation characteristic between two ports of over 70 dB was achieved.

Skeletal muscle is a collection of motor units (MUs) composed of motoneurons and muscle fibers; muscle contraction is regulated by the number and type of MUs. Since sarcopenia and disuse atrophy are caused by atrophy of specific muscle fiber types, it is important to observe mobilized MUs for skeletal muscle diagnosis. In a previous study, we proposed a method to measure multi-channel surface electromyography (EMG) and quantitatively acquire conducting waves, which are potential waveforms propagating on the muscle surface. The mode of MU mobilization by prolonged muscle contraction is not well known. It is necessary to be able to estimate the mobilized MU over time to diagnose slow muscle fibers and to realize the evaluation of muscle activity during training. This study analyzed the conducting waves of multi-channel surface EMG during prolonged muscle contraction in 20 adult male subjects. The results of the changes in the conducting wave during long-duration muscle contractions at high and low loads showed different characteristics, suggesting the possibility of using the propagating wave to elucidate skeletal muscle.