- 著者
- Tomoki WATANABE
- 出版者
- Railway Technical Research Institute
- 雑誌
- Quarterly Report of RTRI (ISSN:00339008)
- 巻号頁・発行日
- vol.41, no.1, pp.5-10, 2000 (Released:2007-10-03)
- 被引用文献数
- 1 2
Inverters have made a great progress due to the development of power semiconductors. Smaller power convertors offer larger passenger rooms and higher productivity. Convertors on-board can be much smaller if we utilize 3.3 kV or 4.5 kV IGBTs and two-level convertors instead of three-level ones. Smaller loss and smaller harmonics are always expected for convertors to enable self-cooling and avoid additional measures for EMC requirements.If 10-40 kV power semiconductors are available, it may be possible to realize transformerless railway vehicles for the 25 kV ac system by assigning convertors with the role of the main transformer in the traction circuit.
- 著者
- Tomoki Watanabe Satoshi Ito Kentaro Yokoi
- 出版者
- Information and Media Technologies 編集運営会議
- 雑誌
- Information and Media Technologies (ISSN:18810896)
- 巻号頁・発行日
- vol.5, no.2, pp.659-667, 2010 (Released:2010-06-15)
- 参考文献数
- 23
The purpose of the work reported in this paper is to detect humans from images. This paper proposes a method for extracting feature descriptors consisting of co-occurrence histograms of oriented gradients (CoHOG). Including co-occurrence with various positional offsets, the feature descriptors can express complex shapes of objects with local and global distributions of gradient orientations. Our method is evaluated with a simple linear classifier on two well-known human detection benchmark datasets: “DaimlerChrysler pedestrian classification benchmark dataset” and “INRIA person data set”. The results show that our method reduces the miss rate by half compared with HOG, and outperforms the state-of-the-art methods on both datasets. Furthermore, as an example of a practical application, we applied our method to a surveillance video eight hours in length. The result shows that our method reduces false positives by half compared with HOG. In addition, CoHOG can be calculated 40% faster than HOG.