It is shown that orbital angular momentum(OAM) is a promising new resource in future classical and quantum communications. However, the separation of OAM modes is still a big challenge. In this paper, we propose a sim...
详细信息
It is shown that orbital angular momentum(OAM) is a promising new resource in future classical and quantum communications. However, the separation of OAM modes is still a big challenge. In this paper, we propose a simple and efficient separation method with a radial varying phase. In the method, specific radial varying phases are designed and modulated for different OAM modes. The resultant beam is focused to the spots with different horizontal and vertical positions after a convex lens, when the coordinate transformation, including two optical elements with coordinate transformation phase and correct phase, operates on the received *** horizontal position of the spot is determined by the vortex phases, and the vertical position of the spot is dependent on the radial varying phases. The simulation and experimental results show that the proposed method is feasible both for separation of two OAM modes and separation of three OAM modes. The proposed separation method is availab.e in principle for any neighboring OAM modes because the radial varying phase is controlled. Additionally, no extra instruments are introduced, and there is no diffraction and narrowing process limitation for the separation.
We present a simple method on the generation of any bi-photon superposition state using only linear *** this scheme, the input states, a two-mode squeezed state and a bi-photon state, meet on a beam-splitter and the o...
详细信息
We present a simple method on the generation of any bi-photon superposition state using only linear *** this scheme, the input states, a two-mode squeezed state and a bi-photon state, meet on a beam-splitter and the output states are post-selected with two threshold single-photon detectors. We carry out corresponding numerical simulations by accounting for practical experimental conditions, calculating both the Wigner function and the state fidelity of those generated bi-photon superposition states. Our simulation results demonstrate that not only distinct nonclassical characteristics but also very high state fidelities can be achieved even under imperfect experimental conditions.
It is known that there exist two kinds of methods for direction-of-arrival (DOA) estimation in the literature: the subspace-based method and the sparsity-based method. However, pervious works reveal that the former me...
详细信息
Analyzing the influence on traffic flow at intersection according to the driving characteristics of modern tram with different lane layout types. Proposing a method of dynamic priority algorithm (DPA) based on the ide...
详细信息
As a power and bandwidth efficient modulation scheme, the optical spatial modulation (SM) technique has recently drawn increased attention in the field of visible light communications (VLC). To guarantee the number of...
详细信息
Cloud computing plays a significant role in big data era since it can provide dynamic, scalab.e virtual resource services via the Internet. However, how to enhance the security level of cloud computing is a challengin...
详细信息
ISBN:
(纸本)9781509045006
Cloud computing plays a significant role in big data era since it can provide dynamic, scalab.e virtual resource services via the Internet. However, how to enhance the security level of cloud computing is a challenging issue which is urgently to be tackled. In this paper, we center on the data security in cloud computing and present an attribute based proxy re-encryption scheme with keyword search (ABPRE-KS) to provide flexible and secure data sharing among users in the cloud. In our scheme, a user's access privileges are described by an access structure consisting of several attributes while ciphertexts are lab.led by several target attributes. A delegator can transform the original ciphertexts into proxy ciphertexts encrypted by the delegatee's attributes without leaking any sensitive information to the cloud server. Besides, a search request on the ciphertexts is allowed by a delegatee if his credentials satisfy the delegatee's access policy. By security analysis, our ABPRE-KS is confidential and keyword semantic secure under BDBH assumption.
Based on the mutual relationship between traffic and land use, the Integrated Transportation and Land Use Model (ITLM) is established from the perspective of urban agglomeration development. The model parameters are c...
详细信息
Based on the mutual relationship between traffic and land use, the Integrated Transportation and Land Use Model (ITLM) is established from the perspective of urban agglomeration development. The model parameters are calibrated by using MATlab.and ArcGIS in combination with information entropy model and Multi-objective Particle Swarm Optimization. From the macro and meso perspectives, the space syntax is used to quantify the transport links of cities in urban agglomerations. Taking the Yangtze River City Group as an example, combined with big data analysis by POI, after optimization of the land use area, population size, and traffic structure of various types of nature through the ITLM model, traffic occurrence and attraction of cities in urban agglomerations tend to be more balanced than the current situation. It plays a vital role in analyzing the current status of cities in urban agglomerations and promoting the further development of urban agglomerations.
At present, speech recognition has become a keytechnology of human-computer interaction, which can be used in semantic recognition and speaker identification and other related applications. This paper focuses on a sp...
At present, speech recognition has become a keytechnology of human-computer interaction, which can be used in semantic recognition and speaker identification and other related applications. This paper focuses on a speaker identification scene and the technical design. Because artificial neural network has the ability to distinguish complex classification boundaries, plenty of work on speech recognition had studied multi-layer perceptual networks to improve the accuracy of classification where back propagation method (BP algorithm) has been used. In the studied scheme, when the test objects (speakers) speak the same isolated word, the identification system can judge who the speaker is by identifying the voice voiceprint of different people. Our design not only considers the recognition based on BP as well as its variant, but also explores the voiceprint recognition based on convolution neural network (CNN). Secondly, the network structure and performance are also compared in detail.
A method to generate the optical vortex beam with arbitrary superposition of different orders of orbital angular momentum (OAM) on a photonic chip is proposed. The distributed Fourier holographic gratings are proposed...
详细信息
暂无评论