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[IEEE 2018 IEEE Conference on Virtual Reality and 3D User Interfaces (VR) - Tuebingen/Reutlingen, Germany (2018.3.18-2018.3.22)] 2018 IEEE Conference on Virtual Reality and 3D User Interfaces (VR) - Impact of Alignment Point Distance Distribution on SPAAM Calibration of Optical See-Through Head-Mounted Displays
摘要： The use of Optical See-Through Head-Mounted Displays (OST-HMDs) for presenting Augmented Reality experiences has become more common, due to the increasing availability of lower cost head-worn device options. Despite this growth, commercially available OST hardware remains devoid of the integrated eye-tracking cameras necessary for automatically calibrating user-specific view parameters, leaving manual calibration methods as the most consistently viable option across display types. The Single Point Active Alignment Method (SPAAM) is currently the most-cited manual calibration technique, due to the relaxation of user constraints with respect to allowable motion during the calibration process. This work presents the first formal study directly investigating the effects that alignment point distribution imposes on SPAAM calibration accuracy and precision. A user experiment, employing a single expert user, is presented, in which SPAAM calibrations are performed under each of five conditions. Four of the conditions cross alignment distance (arm length, room scale) with user pose (sitting, standing). The fifth condition is a control condition, in which the user is replaced with a rigidly mounted camera; the control condition removes the effect of noise from uncontrollable postural sway. The final experimental results show no significant impact on calibration due to user pose (sitting, standing). The control condition also did not differ from the user produced calibration results, suggesting that posture sway was not a significant factor. However, both the user and control conditions show significant improvement using arm's length alignment points over room scale alignments, with an order of magnitude difference in eye location estimate error between conditions.
关键词： Optical see-through head-mounted display,Augmented reality,Single point active alignment method (SPAAM)
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE PELS Workshop on Emerging Technologies: Wireless Power Transfer (WoW) - Montréal, QC, Canada (2018.6.3-2018.6.7)] 2018 IEEE PELS Workshop on Emerging Technologies: Wireless Power Transfer (Wow) - Modeling and Analysis Methods for the DWPT System Applicated in EVs Charging
摘要： The difficulty of modeling a dynamic wireless power transfer (DWPT) system for Electric Vehicles(EVs) charging is that its mutual inductance changes with the coil offset, so we have to build a dynamic model of the system. In this paper,we propose a modeling method by using equivalent circuit method and state space averaging.Moreover,based on the set of system parameters,comparing the results of the simulation experiment with the result of the model calculation.At last, the performance indexes of the system under the different buck duty cycle are observed. The simulation results of these indexes are also basically consistent with the model calculation results, which further verify the accuracy of the model.At the same time,we found that the selection of duty cycle has a great influence on the performance indexes.
关键词： Dynamic Wireless Power Transfer (DWPT),Equivalent Circuit Method,Electric Vehicles(EVs),State Space Averaging,Dynamic Model
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE International Conference on RFID Technology & Application (RFID-TA) - Macau (2018.9.26-2018.9.28)] 2018 IEEE International Conference on RFID Technology & Application (RFID-TA) - Near Field Sources Localization Based on Robust Propagator Method
摘要： The problem of joint direction-of-arrival (DOA) and range estimation of near-field multiple sources under α-stable distributed impulsive noise environments is studied in this paper. The proposed algorithm constructs the MUSIC spectral spectrum based on the noise subspace which is obtained by applying the propagator method on the fractional lower order statistical matrix of the array received signal, and then estimates the multiple sources’ DOA and range parameters by the spectral peak search. Compared with the corresponding algorithms based on second-order statistics, the proposed algorithm can effectively suppress the impulse noise by using the fractional lower-order statistics. At same time, the inherent large computational complexity of the eigenvalue decomposition based methods can also be avoided. Simulation experiments prove the effectiveness of the proposed algorithm.
关键词： impulsive noise,direction of arrival,fraction lower order statistics,range estimation,near-field,propagator method
更新于2025-09-23 15:23:52
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Spectral analysis for photoacoustic pressure sensor designs: Theoretical model improvement and experimental validation
摘要： In the pulsed laser photoacoustic (PA) detection and spectroscopy applications, the fundamental frequency of the PA signal produced, and the sensor resonance frequency should be as close as possible to each other so that analyzes from the obtained signals can be performed effectively. In order to determine the fundamental frequency of the PA wave, a theoretical model approach based on the development of the frequency domain solution of the PA wave equation is presented for use in the PA pressure sensor designs. For the validation of the theoretical model approach, a PA experimental setup was established, and measurements were made in distilled water. The theoretical and experimental PA frequency spectra were determined to be very compatible with each other. Thus, the theoretical model approach was experimentally validated. According to the theoretical model approach, fundamental frequency values obtained from the experimental measurement results were determined with an average accuracy of ? 4.212%. Furthermore, it has been determined that this value has fallen to ?0.267% in the measurements. With the obtained results from the theoretical model approach, we propose that PA pressure sensors with the more selective and narrower band can be designed for more sensitive detection. Moreover, in this study the effects of different laser parameters such that pulse duration, and laser beam width, on the spectral content of the obtained PA signal are analyzed. These analyses will shed light on the vision of acoustic pressure sensor design by helping to select the most optimum parameters for PA detection.
关键词： Theoretical model approach,Photoacoustic wave equation,Acoustic pressure sensor,Frequency domain solution,Pulsed laser photoacoustic method,Spectroscopy
更新于2025-09-23 15:23:52
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Generalization of optical solitons with dual dispersion in the presence of Kerr and quadratic-cubic law nonlinearities
摘要： In this work, nonlinear Schr?dinger’s equation along with group velocity dispersion and spatio-temporal dispersion is considered in (n + 1) dimensions with Kerr and quadratic-cubic law nonlinearities which expose the propagation of light pulses in fiber optics. Dark, singular and periodic singular optical solitons in (n + 1) dimensions are retrieved and generalized through versatile modified simple equation method. The constraint conditions that righteously guarantee the perseverance of these soliton solutions are obtained as an outgrowth. The results presented in this paper are new and generalized which are already available in the literature.
关键词： constraints,(n + 1)-dimensional nonlinear Schr?dinger’s equation,modified simple equation method
更新于2025-09-23 15:23:52
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[ACM Press the 2017 International Conference - Osaka, Japan (2017.10.22-2017.10.24)] Proceedings of the 2017 International Conference on Telecommunications and Communication Engineering - ICTCE '17 - Design of a four-branch optical power splitter using III-nitride semiconductors
摘要： This paper reports the design of a four-branch optical power splitter using MMI structure and taper output branches in III-nitride semiconductors. The numerical experimental is conducted using the 3D FD-BPM method. The results show that the optical power splitter has an excess loss of 0.27 dB and imbalance of 0.12 dB. It is also shown that the proposed design can be realized for C band range. This result opens the opportunity for the future device using this technology.
关键词： FD-BPM method,MMI structure,optical power splitter,III-nitride
更新于2025-09-23 15:23:52
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Growth of vanadium dioxide nanostructures on graphene nanosheets
摘要： The metal oxide/graphene hybrid nanomaterials have been known as promising functional materials for advanced applications such as high capacitive electrode material of secondary batteries, and high sensitive material of high performance gas sensors. Here, morphology controlled vanadium dioxide (VO2) nanostructures were grown on Si wafer and exfoliated graphene by the vapor transport method using a horizontal furnace system. One-dimensional VO2 nanowires were grown on SiO2(300 nm)/Si substrate under 0.4 kPa condition. On the other hand, thick polycrystalline of VO2 platelets were grown on exfoliated graphene nanosheets under 0.4 kPa condition. In addition, polycrystalline VO2 platelets were only grown on exfoliated graphene nanosheets under 101 kPa (atmospheric pressure) condition. The growth of polycrystalline VO2 platelets on graphene nanosheets in atmospheric pressure condition is attributed to preferential growth on functional group of graphene surface such as carbonyl. The functional group is served as nucleation site of VO2 nanostructures.
关键词： Nanostructures,Hybrid Nanomaterials,Vapor Transport Method,Graphene,Vanadium Dioxide
更新于2025-09-23 15:23:52
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Classification of Sugar Beets Based on Hyperspectral and Extreme Learning Machine Methods
摘要： Sugar beet varieties were classified based on hyperspectral technology and the Extreme Learning Machine (ELM) algorithm. The influences of seven pretreatment methods, namely, Savitzky-Golay smoothing (SG), the first derivative (FD) method, SG smoothing combined with the FD method (SG-FD), logarithmic transformation (LT), LT combined with the FD method (LT-FD), the standard normal variate (SNV) method, and SNV combined with the FD method (SNV-FD), on the recognition performance of the ELM model were analyzed to select the best pretreatment method. To simplify the input variables, the standard deviation peak method was used to extract the feature bands for different preprocessed spectral data. The experimental results showed that for different pretreatment methods, the recognition rates of sugar beet varieties by ELM models were all over 80%. Additionally, the combination of different pretreatment methods and FD effectively improved the signal-to-noise ratio and enhanced the accuracy and stability of spectral models. Overall, the recognition accuracy of the ELM models established based on the feature bands was better than that established based on all bands, which suggests that the feature bands extracted by the standard deviation peak method are effective. Based on the SG-FD pretreatment method, the ELM models established using all bands and feature bands both achieved the highest recognition effect. Specifically, the recognition rates of the prediction sets were 93.94% and 95.45%, respectively.
关键词： Standard deviation peak method,ELM,Different pretreatment methods,Sugar beet variety,Hyperspectral
更新于2025-09-23 15:23:52
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Preparation and Enhancement of Luminescent Intensity of New Rare Earth Molybdate NaLa(MoO4)2:Eu3+ Phosphors
摘要： Novel red-emitting rare earth molybdate phosphors NaLa(MoO4)2:Eu3+ have been successfully synthesized by sol-gel method assisted by microwave. The as-synthesized samples were characterized by means of Fourier transform infrared spectroscopy, X-ray diffraction and Fluorescence spectrophotometer, respectively. The results show that the target product NaLa(MoO4)2:Eu3+ have been synthesized by calcining precursor at 800 oC. The obtained samples belong to tetragonal Scheelite-structure and I41/a space group. The excitation spectrum of NaLa(MoO4)2:Eu3+ has a broad band in the range of 250-350 nm and the main peak is at 301 nm. The broad band can be ascribed to the charge transfer band of Mo-O and Eu-O. The sharp lines in 350-500 nm range are due to 4f-4f transitions of Eu3+. The emission spectrum contains a series of narrow peaks, with the main peak at 616 nm originated from the electric dipole transition of 5D0 → 7F2 of Eu3+. The appropriate doping amount of Bi3+ and flux NH4F can enhance luminescent intensity of the sample effectively.
关键词： Rare earth molybdate,Sol-gel method assisted by microwave,Red-emitting phosphors,NaLa(MoO4)2:Eu3+
更新于2025-09-23 15:23:52
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Application of the hybrid complex variable method to the analysis of a crack at a piezoelectric-metal interface
摘要： A plane strain problem for an electrically conducting interface crack between linear transversely isotropic piezoelectric and isotropic elastic conductor materials under remote mechanical loading is considered. The attention is focused on a hybrid complex variable method which combines the Stroh formalism for piezoelectric materials with the Muskhelishvili formalism for conducting isotropic elastic materials. This method is illustrated in detail for the open crack model and the contact zone crack model. Using special presentations of mechanical quantities via sectionally analytic functions, a combined Dirichlet–Riemann and Hilbert boundary value problem is formulated and solved analytically. Stress intensity factors as well as the crack tip energy release rate are found in a clear analytical form. Furthermore, transcendental equations for the determination of the realistic contact zone length and the location of the first interpenetration point have been obtained. A significant influence of the external mechanical loading on the crack opening and the stresses as well as the contact zone and interpenetration region lengths is observed. The dependencies of the mentioned values on the intensities of the mechanical loading are presented in tables and associated diagrams.
关键词： electrically conducting interface crack,Piezoelectric-metal joint,contact zone,complex variable method
更新于2025-09-23 15:23:52