查看更多>>摘要：The protection schemes of the entangle-ment in the system of two entangled atoms from non-Markovian reservoirs via previous Weak measurement (pre-WM) and posterior Weak measurement reversal (post-WMR) are investigated. We firstly compare the effects of combination applying of pre-WM and post-WMR (scheme 1) and twice Weak measurements (WMs) (scheme 2) in the condition of different initial entangled states. The analysis indicates that the protection performance of scheme 1 is much better than that of scheme 2. The scheme 1 was utilized when the system of two entangled atoms suffers from the independent reservoirs. The numerical results show that the combination of pre-WM and post-WMR can effectively enhance entanglement and shorten the time of Entanglement sudden death (ESD) in non-Makovain environment. We have found the optimum of WM strengthens is drastically related to the initial entangled state.
查看更多>>摘要：It is difflcult for existing dense or quasi-dense matching algorithms to obtain accurate matching results due to the lack of effective feature information in non-textured regions. This may affect the quality of subsequent 3D reconstruction and super-resolution reconstruction. We propose a method of non-textured regions matching. To reduce the impact of noise and illumination, vector sampling normalized cross correlation is proposed to directly measure coherence between two colour images by the effective information of multi-channel features. Three mathematical properties are used in affine transformation: 1) Centroid location is not affected by affine transformation; 2) Affine transformation transforms a straight line into another straight line; 3) Affine transformation maintains the linear relation invariant. In non-textured regions, we can construct texture regions which have affine invariant properties to improve the accuracy of template matching. This could provide more information for the diffusion of dense or quasi-dense matching. In experiments, we demonstrate that the method has high accuracy in cases where there is no big distortion between the two viewing angles from two aspects of simulated images and photographic images.
查看更多>>摘要：Inspired by the fact that back-off and interpolated smoothing algorithms have significant effect on statistical language modeling, this paper proposes a sentence-level Language model (LM) score regularization algorithm to improve the fault-tolerance of LMs for recognition errors. The proposed algorithm is applicable to both count-based LMs and neural network LMs. Instead of predicting the occurrence of a sequence of words under a fixed order Markov assumption, we use a composite model consisting of different order models with either n-gram or skip-gram features to estimate the probability of the sequence of words. In order to simplify implementations, we derive a connection between bidirectional neural networks and the proposed algorithm. Experiments were carried out on the Switchboard corpus. Results on N-best lists re-scoring show that the proposed algorithm achieves consistent word error rate reduction when it is applied to count-based LMs, Feedforward neural network (FNN) LMs, and Recurrent neural network (RNN) LMs.
查看更多>>摘要：Aiming at the drawback that the shape of Bézier triangles is fixed with respect to the control points, some blending functions with parameter and with similar properties to the bivariate Bernstein polynomials are presented. Few literatures introduce how do the blending functions are derived. This paper aims at providing the general construction method of adjustable Bézier triangles in polynomial space. With the help of degree elevation technique and based on the idea that the adjustable surfaces are defined by the adjustable control points, the shape adjustable Bézier triangles are defined. The construction process of the blending functions is demonstrated in detail.
查看更多>>摘要：An uplink multi-user massive Multi-input multi-output (MIMO) system is considered with a mixed Analog-to-digital converter (ADC) architecture under imperfect Channel state information (CSI). A closed-form approximation for the Spectral efficiency (SE) is derived for a general mixed ADC structure with any resolution profile. To achieve a balance between the SE and receive Energy efficiency (EE) of the system, the ADC resolution profile optimization problem that maximizes a linear combination of the SE and the Base station (BS) receive power consumption is formulated. An algorithm based on gradient search is proposed whose complexity is linear in the number of BS antennas. Numerical results verify that the proposed ADC resolution design largely outperforms the two-level structure especially in the lower SE region and provides more choices than the uniform-ADC architecture for resolving the SE-EE tradeoff.
查看更多>>摘要：The waveguide gate-type mechanism on micro-channel plate substrate was firstly put forward for the complex photo detection in Free space optical communication (FSO). Based on the losses of energy coupling between both Micro-channel plates (MCP), we further proposed waveguide gate-type complex detecting mechanism, which was verified in electron optic system by vacuum testing. With the application of the complex detecting mechanism, the device performance has greatly improved, including higher space optical transfer and wider dynamic detecting range.
查看更多>>摘要：When a big path difference exists between the multiple transmitter-receiver links, time dispersion is inevitable. A multipath channel model is proposed for Multiple-input multiple-output (MIMO) Visible light communications (VLC). To combat Inter-symbol interference (ISI) as well as increase the channel capacity, a combination of MIMO and Direct-current-biased Optical orthogonal frequency division multiplexing (DCO-OFDM) is studied. The performance analysis of MIMO-DCO-OFDM taking into account the limitation of the forward current of the off-the-shelf LED is derived. The accuracy of the theoretical results is verified by comparison with the Monte Carlo Bit error ratio (BER) simulation results under different DC bias and different clipping levels.
查看更多>>摘要：A multi-energy Demand response man-agement (DRM) approach in Energy Internet is proposed by employing Stackelberg game theory. The multi-energy trading problem in DRM is formulated as a Stackelberg game, where an energy provider, as a leader, adjusts energy prices, and residential smart energy hubs, as followers, dynamically schedule multiple energy flows according to the prices. The existence and uniqueness of the equilibrium of the proposed game model are analyzed. A multi-energy DRM algorithm for reaching the game equilibrium is developed. Simulation results show that the proposed game-based approach can effectively reduce residential energy costs and improve revenues of the energy provider.
查看更多>>摘要：A theoretical Three dimensional (3-D) multiuser High altitude platform (HAP) Multiple-input multiple-output (MIMO) channel model based on dynamic evolution of the Line-of-sight (LOS) components is proposed. In this paper, we consider that the LOS components could re-appear after they have vanished, and a two-state Continuous-time Markov chain (CTMC) is used to model the dynamic evolution of the LOS components. The survival probabilities of the LOS components are derived by using Chapman-Kolmogorov (C-K) equations, and the closed-form expressions are derived in this paper. Using the survival probabilities, the spatial correlation functions are derived. Measurements show that a two-state CTMC is indispensable to investigate the dynamic properties of the LOS components.
查看更多>>摘要：Energy-efficient cooperative spectrum sharing has become a new trend based on financial and environmental considerations. We focus on a novel energy-efficient cooperative strategy in a Radio frequency (RF) energy harvesting cognitive radio network, where the Secondary user (SU) provides energy supply and relaying assist for the Primary user (PU) in exchange for the transmission opportunities. On the basis of energy and information cooperation, an Energy efficiency (EE) maximization non-convex problem for SU is formulated under the PU's Quality of service (QoS) requirement and energy-causality constraint. With the aid of Dinkebalch's method and convex optimization technique, a joint time and power allocation scheme is proposed. Numerical results show that the proposed scheme achieves higher SU's EE and better PU's QoS guarantee compared to the scheme in which the SU only provides energy for the PU's transmission.
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