1,214 research outputs found
Effect of pedestrian movement on MIMO-OFDM channel capacity in an indoor environment
Effects of pedestrian movement on multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) channel capacity have been investigated using experiment and simulation. The experiment was conducted at 5.2 GHz by a MIMO-OFDM packet transmission demonstrator using four transmitters and four receivers built in-house. Geometric optics based ray tracing technique was used to simulate the experimental scenarios. Changes in the channel capacity dynamic range have been analysed for different number of pedestrian (0-3) and antennas (2-4). Measurement and simulation results show that the dynamic range increases with the number of pedestrian and the number of antennas on the transmitter and receiver array
Deterministic diffraction loss modelling for novel broadband communication in rural environments
This paper presents a deterministic modelling approach to predict diffraction loss for an innovative Multi-User-Single-Antenna (MUSA) MIMO technology, proposed for rural Australian environments. In order to calculate diffraction loss, six receivers have been considered around an access point in a selected rural environment. Generated terrain profiles for six receivers are presented in this paper. Simulation results using classical diffraction models and diffraction theory are also presented by accounting the rural Australian terrain data. Results show that in an area of 900 m by 900 m surrounding the receivers, path loss due to diffraction can range between 5 dB and 35 dB. Diffraction loss maps can contribute to determine the optimal location for receivers of MUSA-MIMO systems in rural areas
A "Gauged" Peccei-Quinn Symmetry
The Peccei-Quinn (PQ) solution to the strong problem requires an
anomalous global symmetry, the PQ symmetry. The origin of such a
convenient global symmetry is quite puzzling from the theoretical point of view
in many aspects. In this paper, we propose a simple prescription which provides
an origin of the PQ symmetry. There, the global PQ symmetry is virtually
embedded in a gauged PQ symmetry. Due to its simplicity, this mechanism
can be implemented in many conventional models with the PQ symmetry.Comment: 5 pages, 1 figure
Nonexistence of exceptional imprimitive Q-polynomial association schemes with six classes
Suzuki (1998) showed that an imprimitive Q-polynomial association scheme with
first multiplicity at least three is either Q-bipartite, Q-antipodal, or with
four or six classes. The exceptional case with four classes has recently been
ruled out by Cerzo and Suzuki (2009). In this paper, we show the nonexistence
of the last case with six classes. Hence Suzuki's theorem now exactly mirrors
its well-known counterpart for imprimitive distance-regular graphs.Comment: 7 page
高効率可視光水分解を目指した新規半導体光触媒および助触媒の設計
京都大学0048新制・課程博士博士(工学)甲第21119号工博第4483号新制||工||1697(附属図書館)京都大学大学院工学研究科物質エネルギー化学専攻(主査)教授 阿部 竜, 教授 安部 武志, 教授 陰山 洋学位規則第4条第1項該当Doctor of Philosophy (Engineering)Kyoto UniversityDGA
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