Scientific Machine LearningGeometric Deep LearningBayesian Deep LearningMiscellaneous

Other Themes

We are conducting various research projects to provide appropriate constraints and assistance to the architectures and optimizations of deep learning.

Other Themes

Gradient Search for Deep Neural Networks with Attention Mechanism

Recent advances in Neural Architecture Search (NAS) have made it possible to automatically design efficient architectures for image classification tasks. Convolutional Neural Networks (CNNs) are commonly used in image classification, which rely primarily on convolution and pooling operations. While traditional NAS methods have focused on selecting among these operations, recent work has shown that incorporating attention mechanisms into CNNs can increase representational power, improving accuracy while limiting the growth in parameters. In this study, we propose a method for automatically designing CNNs that integrate attention mechanisms.

  • Kohei Nakai, Takashi Matsubara, and Kuniaki Uehara, "Neural Architecture Search for Convolutional Neural Networks with Attention," IEICE Transactions on Information and Systems, vol. E104.D, no. 2, 2021. J-STAGE
  • Kohei Nakai, Takashi Matsubara, and Kuniaki Uehara, "Att-DARTS: Differentiable Neural Architecture Search for Attention," The 2020 International Joint Conference on Neural Networks (IJCNN2020), Glasgow (Online), Jul. 2020.
    Slide Code

Data Augmentation Using Random Image Cropping and Patching

Deep convolutional neural networks (CNNs) with a very large number of parameters have achieved remarkable success in image processing. However, an excessively large number of parameters is increases the risk of overfitting. To mitigate this, various data augmentation methods have been proposed, such as flipping, cropping, scaling, and color transformations. Building on these techniques, our study introduces a new technique in which we randomly crop four different images and patch them together to form a new training sample, thereby achieving even higher accuracy in image processing tasks.

  • Ryo Takahashi, Takashi Matsubara, and Kuniaki Uehara, "Data Augmentation using Random Image Cropping and Patching for Deep CNNs," IEEE Transactions on Circuits and Systems for Video Technology, vol. 30, no. 9, pp. 2917-2931, 2020.
    IEEE arXiv
  • Ryo Takahashi, Takashi Matsubara, and Kuniaki Uehara, "RICAP: Random Image Cropping and Patching Data Augmentation for Deep CNNs," The 10th Asian Conference on Machine Learning (ACML2018), Beijing, Nov. 2018, pp. 786-798. (acceptance rate 57/230=0.248)
    Paper Code

Human-Like Agents by Combining Reinforcement Learning and Imitation Learning

Reinforcement learning (RL) agents are capable of solving a wide range of tasks, including the board game Go, autonomous driving, and video games. Although RL trains agents to maximize rewards, practical applications demand considerations beyond pure performance. For instance, an agent that is too strong can diminish user enjoyment in video games, while in autonomous driving, excessive acceleration and deceleration may cause passenger anxiety. As a result, there is growing interest in designing agents with more human-like behavior. Imitation learning, which trains agents on expert human policies, can yield human-like actions but cannot surpass the expert's performance. In this study, we propose a method that integrates reinforcement learning with imitation learning, thereby combining the strengths of both approaches. We applied our model to Atari games and the driving simulator TORCS, and experimental evaluation demonstrated that our method outperforms imitation-only agents while exhibiting human-like behavior compared to RL-only agent. This research was conducted as a joint research project with Equos Research Co., Ltd.

  • Rousslan Fernand Julien Dossa, Xinyu Lian, Hirokazu Nomoto, Takashi Matsubara, and Kuniaki Uehara, "Hybrid of Reinforcement and Imitation Learning for Human-Like Agents," IEICE Transactions on Information and Systems, vol. E103.D, no. 9, pp. 1960-1970, 2020.
    J-STAGE
  • Rousslan Fernand Julien Dossa, Xinyu Lian, Hirokazu Nomoto, Takashi Matsubara, and Kuniaki Uehara, "A Human-Like Agent Based on a Hybrid of Reinforcement and Imitation Learning," The 2019 International Joint Conference on Neural Networks (IJCNN2019) , Budapest, Jul. 2019.
    IEEE Slide

Collection of All-Sky Images and Cloud Type Classification

Marine weather observations are essential for safe navigation, and in Japan, even commercial vessels are required to report their findings to the Japan Meteorological Agency. However, conventional weather instruments cannot determine cloud type or cloud cover, requiring observers to rely on visual inspection. Existing approaches developed in other countries are not fully adapted to Japanese weather conditions or reporting standards, highlighting the need for a Japan-specific system. In this study, we developed a device capable of capturing full-sky images, installed it on vessels to collect medium-scale datasets, and labeled cloud types and conditions in the lower, middle, and upper layers of the atmosphere. After training a deep convolutional neural network on these datasets, we confirmed that both cloud type and condition classification achieved accuracies above 0.9. This work was conducted as a joint research project with SKY Perfect JSAT Corporation, Banyan Partners, Kobe Digital Labo Inc., and Professor Osawa of the Graduate School of Maritime Sciences at Kobe University.

Part of the research results has been released as the iOS and Android app "Kumolog." It can be downloaded from the App Store and Google Play. It has also been featured in the Kobe University Press Release, NHK WEB NEWS, Asahi Shimbun, and Nikkan Kogyo Shimbun.

  • 森川優, 中西波瑠, 稲村直樹, 近藤伸明, 小渕浩希, 大澤輝夫, 松原崇, 申吉浩, 大島裕明, 上原邦昭, "船舶における全天球画像のデータ収集と雲形・状態・全雲量の自動判定の試み," 日本気象学会機関誌「天気」, vol. 70, no. 12, pp. 577-692, 2023.
  • Naoki Inamura, Kota Fujiwara, Takahisa Amakata, Fumio Tsuri, Haru Nakanishi, Hiroki Obuchi, Teruo Osawa, Takashi Matsubara, Kuniaki Uehara, "Solar Power Generation Prediction Using All-Sky Images and Solar Radiation Data," 2020 Annual Conference of the Japanese Society for Artificial Intelligence (JSAI2020), Kumamoto, June, 2020.
  • Yu Morikawa, Haru Nakanishi, Naoki Inamura, Nobuaki Kondo, Hiroki Obuchi, Teruo Osawa, Takashi Matsubara, Kuniaki Uehara, "Data Collection of All-Sky Images and Cloud Type and State Judgment," 2018 Annual Conference of the Japanese Society for Artificial Intelligence (JSAI2018), 2A4-01, Kagoshima, June, 2018.