電気学会論文誌C(電子・情報・システム部門誌)
Online ISSN : 1348-8155
Print ISSN : 0385-4221
ISSN-L : 0385-4221
142 巻, 10 号
選択された号の論文の17件中1~17を表示しています
特集:電子材料関連技術の最近の進展
特集論文
<電子物性・デバイス>
<光工学>
  • 部谷 学, 舟山 博人, 小澤 健治
    2022 年 142 巻 10 号 p. 1068-1074
    発行日: 2022/10/01
    公開日: 2022/10/01
    ジャーナル 認証あり

    In order to establish a method to precisely predict penetration depths for macro and micro laser welding at manufacturing sites, we have investigated how to determine experimental conditions for Hablanian plot. We need to obtain three approximate curves (standard approximate curve, error approximate curve, and coefficient approximate curve) for an accurate prediction of penetration depths. We have discussed how to obtain three approximate curves using laser welding data by the use of the fiber laser. As a result, the following findings could be derived. (1) Cubic polynomial is probable as one of the candidates of a function for three approximate curves. (2) A focusing lens used and a spot diameter should be first determined. Second, laser welding experiments should be carried out with changing Log10(Vd/K) and P at regular intervals. (3) Prediction errors can be respectively reduced down to ∼0.06 and ∼0.03 for macro and micro welding above a penetration depth of 4 mm and 0.4 mm.

  • 佐藤 雄二, 森本 雄喜, 小野 和宏, 竹中 啓輔, 鎌田 恒好, 部谷 学, 塚本 雅裕
    2022 年 142 巻 10 号 p. 1075-1080
    発行日: 2022/10/01
    公開日: 2022/10/01
    ジャーナル 認証あり

    A copper has been widely applied for various industrial components such as heat exchangers, heat pipes, electro circuits and motors because of having excellent properties such as thermal conductivity and electrical conductivity. Besides the copper is expected to be used for handrails, doorknobs etc., which touched by many people to prevent from infectious diseases because of having the excellent properties such as an antibacterial property and a virus inactivation property. However, copper is low strength to only about 40% as strong as stainless steel. To add a new function of virus inactivation property to the surface keeping the strength, it is necessary to develop a coating technology to form a copper layer on the surface. Thus, we have developed a multi beam type laser metal deposition method with a high intensity blue diode laser which newly developed with an output power of 200W. As a result, Cu-Zn alloy layer was formed on the stainless-steel plate with no pores at the output power of 30W and scanning speed of 6mm/s.

論文
<電気回路・電子回路>
  • 西山 直哉, 松井 文也, 佐野 勇司
    2022 年 142 巻 10 号 p. 1081-1090
    発行日: 2022/10/01
    公開日: 2022/10/01
    ジャーナル 認証あり

    In order to compensate the non-linear characteristics in many kinds of electronic devices, the exponentiation conversion circuit that can change the power exponent to any value has been proposed. The exponentiation conversion circuit multiplies the logarithmically converted input signal by the power exponent value to perform exponential conversion. As a result, we can obtain the power function characteristic of the power exponent value. In this paper, we proposed a transconductance circuit that can increase the voltage gain, which decreases with lower power supply voltage. By parallelizing the input and output signal voltage windows with the transconductance circuit, the maximum exponent value was secured to be 2.9, which is equivalent to the conventional value, furthermore the signal dynamic range was 42.7 dB in simulation results. By evaluating its prototype IC with 0.6 µm CMOS process, we confirmed the signal dynamic range was 30.0 dB and maximum power exponent value was 3.4.

<情報通信工学>
<生体医工学・福祉工学>
<システム・計測・制御>
<知能,ロボティクス>
  • 宮下 翼, 松本 和幸, 吉田 稔, 西村 良太, 北 研二
    2022 年 142 巻 10 号 p. 1144-1155
    発行日: 2022/10/01
    公開日: 2022/10/01
    ジャーナル 認証あり

    Tackling diabetes, an increasingly common lifestyle-related illness, requires information on patients’ lifestyle and habits. Blogs maintained by patients afflicted with the incurable illness may be useful for analyzing how lifestyle affects health-status. In this paper, we propose an intrinsic expression extractor that extracts keywords related to lifestyle and health-status from blogs of patients diagnosed with type-2 diabetes. To counter class imbalance and add to the corpus, the proposed method tags each keyword with information based on cue-words extracted from manually tagged data. The named-entity recognition (NER) for the extracted keywords uses a bidirectional gated recurrent unit neural network (BiGRU) and was evaluated for accuracy by cross-validation. We obtained F1-score of approximately 0.76. Although the accuracy of extraction can further be improved, the novel approach has applications in analyzing and improving the lifestyle of diabetes-afflicted patients.

<ソフトコンピューティング・学習>
  • 行木 大輝, 山口 智
    2022 年 142 巻 10 号 p. 1156-1165
    発行日: 2022/10/01
    公開日: 2022/10/01
    ジャーナル 認証あり

    Adam is one of the general optimization algorithms in neural networks. It can accelerate convergence speed while learning. It has, however, two problems. The first is that the final performance of a network trained by Adam, such as generalization ability, becomes worse than the one trained by SGD, in applications to large-scale networks. The second is that values of the learning rate tend to be large at the early learning stage; as a result, the values of network parameters, such as weights and bias, become too large by a first few iterations. In recent years, research has been conducted to solve these problems. AdaBound has been proposed for solving the first problem. This is a method switching dynamically from Adam to SGD. RAdam has also been proposed, for solving the second problem. This applies a method called WarmUp, which sets a small learning rate at the early learning stage and gradually increases it, to Adam. In this study, we propose to apply WarmUp to the upper limit of AdaBound's learning rate. The proposed algorithm prevents parameter updates at extremely large learning rates in the early learning stages. Therefore, more efficient learning can be expected than the conventional method. The proposed method has been applied to learning of some types of networks like CNN, ResNet, DenseNet and BERT. The results show that our method has improved performance compared to the traditional method, and an image classification task has shown a tendency to be more effective in large networks.

<メタボリズム社会,環境システム>
  • M V Narayana, Devendra Jalihal, Shiva Nagendra S M
    2022 年 142 巻 10 号 p. 1166-1171
    発行日: 2022/10/01
    公開日: 2022/10/01
    ジャーナル 認証あり

    Air quality monitoring (AQM) at fine and granular levels helps in implementing better air pollution control and mitigation plans. Low-cost sensing is a relatively new paradigm for AQM at high spatial and temporal resolutions. However, the data obtained in this technique is less reliable due to various error sources involved. Calibration is a promising approach to counteract error sources and to improve the accuracy of the data obtained from low-cost sensors (LCS). However, fitting a calibration model that works for every application is cumbersome since each application is associated with varying sources of error. Hence, we focus on finding a better calibration model for a given application. Our approach is application-centric. We classify LCS applications into static and mobile, based on sensor deployment in the field. Then, we sub-categorize both stationary and mobile applications further to narrow down to understand each case. Next, we analyze the possible error sources in each application and the corresponding techniques to counteract them. Then, we map applications to the calibration models via possible error sources and assign weights/scores to each parameter based on our analysis. Our quantitative analysis determines scores for each calibration model which results in finding the best suited model for a given set of conditions and applications based on the highest score. We verify our analysis with real time data obtained from LCS deployed in Chennai city, India.

研究開発レター
<生体医工学・福祉工学>
  • 原川 信二, 堀 卓也, 鈴木 宏志
    2022 年 142 巻 10 号 p. 1172-1173
    発行日: 2022/10/01
    公開日: 2022/10/01
    ジャーナル 認証あり

    The objective of the present study was to evaluate the effect of extremely low frequency (ELF)-electric field (EF) treatment on decubitus ulcer. Hairless mice (Hr-/kud) were used, and ulcers were formed by magnetic compression of the back skin. The extent of the ulcer was assessed by the diameter of the wound and the crust area. The observation period was 14 days from the day of pressure. Three experimental groups were assigned: a group treated with EF from before the formation of the pressure ulcer until the end of observation, a group that started EF treatment on the day of magnet compression, and a control group that only had pressure ulcer formation. EF was generated at 50Hz at 10kV/m between parallel plate electrodes. EF treatment on the mice was 60 minutes per day. Results showed that the maximum wound diameter was reached in all groups for 3 days. Both decubitus ulcer diameter and crust diameter in the field-treated group were smaller than those in the control group, suggesting an inhibitory effect of ELF-EF on the process of decubitus ulcer development and repair.

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