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.

Relaxed Stabilization Criterion for T–S Fuzzy Systems by Minimum-Type Piecewise-Lyapunov-Function-Based Switching Fuzzy Controller

Abstract: This paper proposes the minimum-type piecewise-Lyapunov-function-based switching fuzzy controller that switches accompanying the piecewise Lyapunov function. By applying this switching fuzzy controller with the minimum-type piecewise Lyapunov function, the relaxed stabilization criterion is obtained for continuous Takagi-Sugeno (T-S) fuzzy systems. Some conditions of the relaxed stabilization criterion are represented by bilinear matrix inequalities (BMIs), which contain some bilinear terms as the product of a full matrix and a scalar. According to the literature, the path-following method is very effective for this kind of BMI problem; hence, it is utilized to obtain solutions of the criterion. Xie et al. in 1997 chose two types (i.e., minimum type and maximum type) of piecewise Lyapunov functions as the Lyapunov function candidates. The reasons for why this study only chooses the minimum-type piecewise Lyapunov function as the Lyapunov function candidate are illustrated. Moreover, the numerical example shows the relaxation of the proposed criterion.

VANET Broadcast Protocol Based on Fuzzy Logic and Lightweight Retransmission Mechanism

Abstract: Vehicular ad hoc networks have been attracting the interest of both academic and industrial communities on account of their potential role in Intelligent Transportation Systems (ITS). However, due to vehicle movement and fading in wireless communications, providing a reliable and efficient multi-hop broadcast service in vehicular ad hoc networks is still an open research topic. In this paper, we propose FUZZBR (FUZZy BRoadcast), a fuzzy logic based multi-hop broadcast protocol for information dissemination in vehicular ad hoc networks. FUZZBR has low message overhead since it uses only a subset of neighbor nodes to relay data messages. In the relay node selection, FUZZBR jointly considers multiple metrics of inter-vehicle distance, node mobility and signal strength by employing the fuzzy logic. FUZZBR also uses a lightweight retransmission mechanism to retransmit a packet when a relay fails. We use computer simulations to evaluate the performance of FUZZBR.

Incommensurate spin fluctuations in hole-overdoped superconductor KFe2As2.

Abstract: A neutron scattering study of heavily hole-overdoped superconducting ${\mathrm{KFe}}_{2}{\mathrm{As}}_{2}$ revealed a well-defined low-energy incommensurate spin fluctuation at [$\ensuremath{\pi}(1\ifmmode\pm\else\textpm\fi{}2\ensuremath{\delta}),0$] with $\ensuremath{\delta}=0.16$. The incommensurate structure differs from the previously observed commensurate peaks in electron-doped $A{\mathrm{Fe}}_{2}{\mathrm{As}}_{2}$ ($A=\mathrm{Ba}$, Ca, or Sr) at low energies. The direction of the peak splitting is perpendicular to that observed in $\mathrm{Fe}(\mathrm{Te},\mathrm{Se})$ or in $\mathrm{Ba}(\mathrm{Fe},\mathrm{Co}{)}_{2}{\mathrm{As}}_{2}$ at high energies. A band structure calculation suggests interband scattering between bands around the $\ensuremath{\Gamma}$ and $X$ points as an origin of this incommensurate peak. The perpendicular direction of the peak splitting can be understood within the framework of multiorbital band structure. The results suggest that spin fluctuation is more robust in hole-doped than in electron-doped samples, which can be responsible for the appearance of superconductivity in the heavily hole-doped samples.

An Emergency Medical Communications System by Low Altitude Platform at the Early Stages of a Natural Disaster in Indonesia

Abstract: A natural disaster is a consequence of a natural hazard, such as a tsunami, earthquake or volcanic eruption, affecting humans. In order to support emergency medical communication services in natural disaster areas where the telecommunications facility has been seriously damaged, an ad hoc communication network backbone should be build to support emergency medical services. Combinations of requirements need to be considered before deciding on the best option. In the present study we have proposed a Low Altitude Platform consisting of tethered balloons combined with Wireless Fidelity (WiFi) 802.11 technology. To confirm that the suggested network would satisfy the emergency medical service requirements, a communications experiment, including performance service measurement, was carried out.