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Predicting the structure and stability of titanium oxide electrides
摘要： The search for new inorganic electrides has attracted significant attention due to their potential applications in transparent conductors, battery electrodes, electron emitters, as well as catalysts for chemical synthesis. However, only a few inorganic electrides have been successfully synthesized thus far, limiting the variety of electride examples. Here, we show the stabilization of inorganic electrides in the Ti-rich Ti–O system through first-principles calculations in conjunction with swarm-intelligence-based CALYPSO method for structure prediction. Besides the known Ti-rich stoichiometries of Ti2O, Ti3O, and Ti6O, two hitherto unknown Ti4O and Ti5O stoichiometries are predicted to be thermodynamically stable at certain pressure conditions. We found that these Ti-rich Ti–O compounds are primarily zero-dimensional electrides with excess electrons confined in the atom-sized lattice voids or between the cationic layers playing the role as anions. The underlying mechanism behind the stabilization of electrides has been rationalized in terms of the excess electrons provided by Ti atoms and their accommodation of excess electrons by multiple cavities and layered atomic packings. The present results provide a viable direction for searching for practical electrides in the technically important Ti–O system.
关键词： first-principles calculations,inorganic electrides,Ti-rich Ti–O system,structure prediction,CALYPSO method
更新于2025-09-04 15:30:14
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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - Radiation Characteristics of EWE Antenna on Actual Ground for Landslides Prediction Based on Bistatic Radar System Using AM Radio Broadcasting
摘要： The complex permittivities of the hydrated soil have been measured and the transmission characteristics of the electromagnetic wave in air-hydrated soil boundary have been calculated as the first step of the realization of the landslides prediction system so far. Consequently, it becomes obvious that the reflected wave from the hydrated soil increases as the water content increases and the transmitting wave decreases until it is difficult to measure. Keeping this results in mind, the antenna called EWE at operating frequency of 1MHz has been investigated in order to measure the reflected wave from lands in this paper. The miniaturization and the influence of the conductivity of the ground have been considered.
关键词： MF-Band,Landslides prediction,Antenna,Bistatic radar
更新于2025-09-04 15:30:14
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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - Efficient RF Coverage Prediction through a fully Discrete, GPU-Parallelized Ray-Launching model
摘要： A fully discrete Ray Launching field prediction algorithm that takes advantage of environment visibility preprocessing for both diffuse and specular interactions is presented and used to perform efficient RF coverage prediction in large environments. The algorithm, being discrete, has been parallelized in a straightforward way on NVIDIA-compatible Graphical Processing Units. These innovative features combined allow to achieve a computation time reduction of about three orders of magnitude compared to conventional algorithms, while retaining the same accuracy level.
关键词： RF prediction,GPU,ray launching,propagation,measurement
更新于2025-09-04 15:30:14
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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - Numerical Weather Prediction Models for the Estimate of Clear-Sky Attenuation Level in Alphasat Beacon Measurement
摘要： With the move of satellite systems towards Ka and QIV bands, the Alphasat TDPS Aldo Paraboni scientific experiment aims to characterize atmospheric attenuation in those bands. However, during the retrieval of the attenuation from the measured beacon signal, the clear-sky contribution to attenuation is lost. Microwave radiometers give the clear sky absolute reference level, but these are costly and not always available. This paper proposes Numerical Weather Prediction models as an alternative source of clear-sky attenuation. Three months of beacon and radiometric data from Spino d' Adda the Alphasat receiving station are used as benchmark for validation of the method. A preliminary conclusion is that gaseous attenuation is well predicted, but cloud attenuation is underestimated.
关键词： microwave radiometer,Numerical Weather Prediction model,radiowave propagation,clear-sky attenuation,Alphasat
更新于2025-09-04 15:30:14
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Reduction of Forced Outages in Islanded Microgrids by Compensating Model Uncertainties in PV Rating and Battery Capacity
摘要： Energy management systems for islanded microgrids often rely on predictions of energy availability and usage. Such predictions can be used to plan actions, such as shedding non-essential loads, so that critical loads continue to be served. However, uncertainties in the prediction models may lead to incorrect decisions, and subsequently jeopardize reliable operation of the microgrid. For a photovoltaic (PV) and battery based microgrid, uncertainties in the PV rating and the battery capacity model parameters can lead to otherwise avoidable outages. In this paper, techniques have been developed to identify and compensate for such model uncertainties. The approach uses differences between the actual and predicted data sequences to determine compensation factors to improve prediction accuracy. The developed techniques account for operating condition changes automatically, and no additional sensors are needed for their implementation. The method has been evaluated using data from rooftop irradiance and temperature sensors and the corresponding forecasts. It has been shown that the proposed techniques can improve the accuracy of the predictions and hence lead to more effective energy management decisions. Together with a pre-emptive load shedding strategy, the total outage time of the microgrid can be shortened by as much as 11% for the chosen scenario.
关键词： Energy management,photovoltaic systems,prediction model uncertainties,microgrids
更新于2025-09-04 15:30:14
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Iterative Reweighted Tikhonov-regularized Multihypothesis Prediction Scheme for Distributed Compressive Video Sensing
摘要： Distributed compressive video sensing (DCVS) has great potential for signal acquisition and processing in source-limited communication, e.g., wireless video sensors network (WVSN), because it shifts complicated motion estimation and motion compensation from the encoder to the decoder. Known as a state-of-the-art technique in DCVS, multihypothesis (MH) prediction is widely used because of its acceptable performance and low computational complexity. However, this technique is restricted by inaccurate regularizations, which can cause susceptibility to inaccurate hypotheses. In this paper, we present an iterative reweighted Tikhonov-regularized scheme for MH prediction reconstruction. Specifically, to enhance robustness, this scheme proposes a reweighted Tikhonov regularization (MH-RTIK) that synthetically considers three factors that affect MH prediction performance—accuracy of the hypothesis set, number of hypotheses, and accuracy of regularizations—by utilizing the influence of each hypothesis. Furthermore, to avoid over-iteration in iterative MH prediction reconstruction, we propose a Bhattacharyya coefficient-based stopping criterion for use in the recovery of non-key frames, in which we exploit the similarity to an adjacent key frame rather than a previous iteration result. The simulation results show that the proposed scheme outperforms the state-of-the-art MH methods in terms of robustness to inaccurate hypotheses when there are a limited number of hypotheses.
关键词： Distributed compressive video sensing (DCVS),video reconstruction,wireless video sensors network (WVSN),multihypothesis (MH) prediction
更新于2025-09-04 15:30:14
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A weighting intersection point prediction iteration optimization algorithm used in photogrammetry for port hoisting machinery
摘要： As a mature technology, photogrammetry is widely applied in today's engineering measurement field. However, because of the limitation of the port condition, it is impossible to obtain photos that are taken at ideal angles and distances when photogrammetry is used to measure port hoisting machinery, and this leads to invalid measurements with low accuracy data. To solve this problem, a new algorithm is proposed in this work. First, the proposed method introduces redundant measurements through an intersection point prediction algorithm to improve the measurement data’s accuracy. Second, a weighting algorithm based on the lens distortion model is then provided to further improve accuracy. Third, an iterative method is established from the threshold setting method based on the weighting algorithm. Thus, the quality of the final measurement could be controllable. Finally, an experiment is devised for the characteristics of the algorithm and the port condition. The results demonstrate that the method described in this paper significantly improves the accuracy of the measuring results of photogrammetry while photos used for the calculation were taken at unsatisfactory angles and distances caused by the limitation of the port condition.
关键词： Intersection point prediction,Photogrammetry,Weighting,Port hoisting machinery,Iteration
更新于2025-09-04 15:30:14
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Multivariate Spatio-temporal Solar Generation Forecasting: A Unified Approach to Deal With Communication Failure and Invisible Sites
摘要： Short-term prediction of multivariate dynamical processes evolving over time when data are partially observable is a challenging task. The power from solar resources has reached grid parity and must be predicted based on real-time observations available up to the current time step to ensure efficient power systems operation. However, solar data in the form of a time series generated by a network of sensors are not always available. Invisible solar sites and communication failure are two causes that leave the energy management data acquisition system with an incomplete solar time series, thus leading to inaccurate forecasts. This paper addresses the impact of partially observable measurements on short-term solar power prediction. We present a low-rank tensor learning scheme to predict six-hour-ahead solar power generation. We use actual multivariate spatio-temporal National Renewable Energy Laboratory solar data in the state of Kansas presented in the form of tensors along with a photovoltaic power conversion model. A design of experiments experimental framework has been proposed to evaluate single and joint effects of spatio-temporal partially observable sites and the regulating parameters on forecasting accuracy. Numerical results show the capability of the framework to uncover detailed insight into the forecasting model behavior.
关键词： tensor,design of experiments (DOE),invisible sites,missing data,spatio-temporal prediction,Communication failure
更新于2025-09-04 15:30:14