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.

Attribute-based encryption with partially hidden encryptor-specified access structures

Abstract: We propose attribute-based encryption schemes where encryptor-specified access structures (also called ciphertext policies) are hidden By using our schemes, an encryptor can encrypt data with a hidden access structure A decryptor obtains her secret key associated with her attributes from a trusted authority in advance and if the attributes associated with the decryptor's secret key do not satisfy the access structure associated with the encrypted data, the decryptor cannot decrypt the data or guess even what access structure was specified by the encryptor We prove security of our construction based on the Decisional Bilinear Diffie-Hellman assumption and the Decision Linear assumption In our security notion, even the legitimate decryptor cannot obtain the information about the access structure associated with the encrypted data more than the fact that she can decrypt the data

Optical properties and highly efficient laser oscillation of Nd:YAG ceramics

Abstract: Optical absorption, emission spectra have been measured for polycrystalline Nd-doped Y3Al5O12 ceramics. Fluorescence lifetimes of 257.6 μs, 237.6 μs, 184.2 μs and 95.6 μs have been obtained for 0.6%, 1%, 2% and 4% neodymium-doped YAG ceramics, respectively. For the first time, highly efficient laser oscillation at 1064 nm has been obtained with this kind of ceramics. Slope efficiency of 53% has been achieved on a uncoated 4.8-mm thick 1% Nd:YAG ceramics sample. Optical to optical conversion efficiency is 47.6%. Laser oscillation has also been obtained with a 2% Nd:YAG ceramics. The optical properties and laser output results have been compared with that of Nd:YAG single crystal grown by the Czochralski method. Almost identical results have been achieved including laser experiments results. But fabrication of Nd:YAG ceramics is much easier compared to the single-crystal growth method. And also large size (now of about 400 mm diameter×5 mm is available) and high-concentration (>1%) Nd:YAG ceramics can be fabricated. The results show that this kind of Nd:YAG ceramics is a very good alternative to Nd:YAG single crystal.

Climbing the Apex of the ORR Volcano Plot via Binuclear Site Construction: Electronic and Geometric Engineering.

Abstract: Great enthusiasm in single-atom catalysts (SACs) for the oxygen reduction reaction (ORR) has been aroused by the discovery of M-NX as a promising ORR catalysis center. However, the performance of SACs lags far behind that of state-of-the-art Pt due to the unsatisfactory adsorption-desorption behaviors of the reported catalytic centers. To address this issue, rational manipulation of the active site configuration toward a well-managed energy level and geometric structure is urgently desired, yet still remains a challenge. Herein, we report a novel strategy to accomplish this task through the construction of an Fe-Co dual-atom centered site. A spontaneously absorbed electron-withdrawing OH ligand was proposed to act proactively as an energy level modifier to empower easy intermediate desorption, while the triangular Fe-Co-OH coordination facilitates O-O bond scission. Benefiting from these attributes, the as-constructed FeCoN5-OH site enables an ORR onset potential and half-wave potential of up to 1.02 and 0.86 V (vs RHE), respectively, with an intrinsic activity over 20 times higher than the single-atom FeN4 site. Our finding not only opens up a novel strategy to tailor the electronic structure of an atomic site toward boosted activity but also provides new insights into the fundamental understanding of diatomic sites for ORR electrocatalysis.

Accumulation of anchored proteins forms membrane diffusion barriers during neuronal polarization

Abstract: The formation and maintenance of polarized distributions of membrane proteins in the cell membrane are key to the function of polarized cells In polarized neurons, various membrane proteins are localized to the somatodendritic domain or the axon Neurons control polarized delivery of membrane proteins to each domain, and in addition, they must also block diffusional mixing of proteins between these domains However, the presence of a diffusion barrier in the cell membrane of the axonal initial segment (IS), which separates these two domains, has been controversial: it is difficult to conceive barrier mechanisms by which an even diffusion of phospholipids could be blocked Here, by observing the dynamics of individual phospholipid molecules in the plasma membrane of developing hippocampal neurons in culture, we found that their diffusion was blocked in the IS membrane We also found that the diffusion barrier is formed in neurons 7-10 days after birth through the accumulation of various transmembrane proteins that are anchored to the dense actin-based membrane skeleton meshes being formed under the IS membrane We conclude that various membrane proteins anchored to the dense membrane skeleton function as rows of pickets, which even stop the overall diffusion of phospholipids, and may represent a universal mechanism for formation of diffusion barriers in the cell membrane

Fuzzy descriptor systems and nonlinear model following control

Abstract: This paper defines a fuzzy descriptor system by extending the ordinary Takagi-Sugeno (T-S) fuzzy model. Several kinds of stability conditions for the fuzzy descriptor system are derived and represented in terms of linear matrix inequalities (LMIs). We illustrate an example of defining the fuzzy descriptor system instead of the ordinary T-S fuzzy model. An LMI design approach is employed to find stable feedback gains and a common Lyapunov function. In addition, this paper presents a nonlinear model following control for the fuzzy descriptor system. A new parallel distributed compensation, the so-called "twin parallel distributed compensations" (TPDC) to realize the nonlinear model following control, is proposed. We present a design technique based on the TPDC. The proposed method is a unified approach to nonlinear model following control. It contains the regulation and servo control problems as special cases.