University of Electro-Communications

About: University of Electro-Communications is a education organization based out in Tokyo, Japan. It is known for research contribution in the topics: Laser & Robot. The organization has 8041 authors who have published 16950 publications receiving 235832 citations. The organization is also known as: UEC & Denki-Tsūshin Daigaku.

Category-Based Deep CCA for Fine-Grained Venue Discovery From Multimodal Data

Abstract: In this work, travel destinations and business locations are taken as venues. Discovering a venue by a photograph is very important for visual context-aware applications. Unfortunately, few efforts paid attention to complicated real images such as venue photographs generated by users. Our goal is fine-grained venue discovery from heterogeneous social multimodal data. To this end, we propose a novel deep learning model, category-based deep canonical correlation analysis. Given a photograph as input, this model performs: 1) exact venue search (find the venue where the photograph was taken) and 2) group venue search (find relevant venues that have the same category as the photograph), by the cross-modal correlation between the input photograph and textual description of venues. In this model, data in different modalities are projected to a same space via deep networks. Pairwise correlation (between different modality data from the same venue) for exact venue search and category-based correlation (between different modality data from different venues with the same category) for group venue search are jointly optimized. Because a photograph cannot fully reflect rich text description of a venue, the number of photographs per venue in the training phase is increased to capture more aspects of a venue. We build a new venue-aware multimodal data set by integrating Wikipedia featured articles and Foursquare venue photographs. Experimental results on this data set confirm the feasibility of the proposed method. Moreover, the evaluation over another publicly available data set confirms that the proposed method outperforms state of the arts for cross-modal retrieval between image and text.

Radially polarized ring and arc beams of a neodymium laser with an intra-cavity axicon.

Abstract: Placing a Brewster-angle axicon inside a laser resonator makes it possible to produce a radially-polarized (RP) oscillation pattern distributed on a thin ring or a portion of a ring. Laser-diode end-pumped, Nd:Y3Al5O12 and Nd:YVO4 lasers were studied. Spatially coherent RP beams distributed on circular arcs were obtained with a polarization contrast ratio up to 80:1. Incoherent RP outputs on a full ring were also produced with a polarization contrast ratio of about 5:1. Applications of these beams to increase absorption efficiency in laser-matter interaction are discussed.

Nano-grain evolution in austenitic stainless steel during multi-directional forging

Abstract: Nano-grain evolution in an austenitic stainless steel (SUS 316) during multidirectional forging (MDF) was investigated at temperatures of 77 K and 300 K. The flow stress during MDF and the room-temperature hardness increased significantly with increasing cumulative strain. The initial grains were subdivided by mechanical twinning and martensitic transformation. The formation of packets , which are composed of lamellar-structured mechanical twins with a spacing of 10–300 nm, enhanced grain fragmentation. The packet size ranged from 40 nm to 100 nm depending on the MDF temperature and the cumulative strain. Tensile tests at ambient temperatures revealed a maximum proof strength of 2.1 GPa. While the proof strength increased with cumulative strain, the plastic strain at fracture was approximately 10% independent of the cumulative strain over ∑Δ ɛ = 2.4.

Alloying Strategy in Cu–In–Ga–Se Quantum Dots for High Efficiency Quantum Dot Sensitized Solar Cells

Abstract: I–III–VI2 group “green” quantum dots (QDs) are attracting increasing attention in photoelectronic conversion applications. Herein, on the basis of the “simultaneous nucleation and growth” approach, Cu–In–Ga–Se (CIGSe) QDs with light harvesting range of about 1000 nm were synthesized and used as sensitizer to construct quantum dot sensitized solar cells (QDSCs). Inductively coupled plasma atomic emission spectrometry (ICP-AES), wild-angle X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analyses demonstrate that the Ga element was alloyed in the Cu–In–Se (CISe) host. Ultraviolet photoelectron spectroscopy (UPS) and femtosecond (fs) resolution transient absorption (TA) measurement results indicate that the alloying strategy could optimize the electronic structure in the obtained CIGSe QD material, thus matching well with TiO2 substrate and favoring the photogenerated electron extraction. Open circuit voltage decay (OCVD) and impedance spectroscopy (IS) tests indicate that the intrinsic re...