This paper proposes a new multitarget constant modulus array structure for code division multiple access (CDMA) systems. The new algorithm for the structure is called pre-despreading and wavelet denoising constant mod...This paper proposes a new multitarget constant modulus array structure for code division multiple access (CDMA) systems. The new algorithm for the structure is called pre-despreading and wavelet denoising constant modulus algorithm (D-WD-CMA). In the new algorithm, the pre-despreading is applied to multitarget arrays to remove some multiple access inter- ferences. After that the received signal is subjected to wavelet de-noising to reduce some noise, and used in CMA adaptive iteration for signal separation. Simulation results showed that the proposed algorithm performed better than the traditional CMA algorithm.展开更多
The configuration of the novel three-stage L-band erbium-doped fiber amplifier with very large and flat gain and very low noise figure presented in this paper uses the forward ASE (amplified spontaneous emission) from...The configuration of the novel three-stage L-band erbium-doped fiber amplifier with very large and flat gain and very low noise figure presented in this paper uses the forward ASE (amplified spontaneous emission) from the first section of the EDF (erbium-doped fiber) and the backward ASE from the third section of the EDF (both serve as the secondary pump sources of energy) to pump the second EDF. To improve the pump efficiency, the power of the pump is split into two parts (with a ratio of e.g. 2:7). The characteristics of this L-band EDFA are studied on the basis of the Giles Model with ASE.展开更多
Image or video resources are often received in poor condition, mostly with noise or defects making the resources hard to read. We propose an effective algorithm based on digital image inpainting. The mechanism can be ...Image or video resources are often received in poor condition, mostly with noise or defects making the resources hard to read. We propose an effective algorithm based on digital image inpainting. The mechanism can be used in restoring images or video frames with very high noise or defect ratio (e.g., 90%). The algorithm is based on the concept of image subdivision and estimation of color variations. Noises inside blocks of different sizes are inpainted with different levels of surrounding information. The results showed that an almost unrecognizable image can be recovered with visually good result. The algorithm can be further extended for processing motion picture with high percentage of noise.展开更多
This work presents two robust quantum secure communication schemes with authentication based on Einstein-Podolsky-Rosen(EPR) pairs, which can withstand collective noises. Two users previously share an identity string ...This work presents two robust quantum secure communication schemes with authentication based on Einstein-Podolsky-Rosen(EPR) pairs, which can withstand collective noises. Two users previously share an identity string representing their identities. The identity string is encoded as decoherence-free states(termed logical qubits), respectively, over the two collective noisy channels, which are used as decoy photons. By using the decoy photons, both the authentication of two users and the detection of eavesdropping were implemented. The use of logical qubits not only guaranteed the high fidelity of exchanged secret message, but also prevented the eavesdroppers to eavesdrop beneath a mask of noise.展开更多
Research of superconducting nanowire singlephoton detectors(SNSPDs) has been progressing rapidly in recent years. The combined properties of high efficiency,low noise, and fast speed of SNSPDs permit its applications ...Research of superconducting nanowire singlephoton detectors(SNSPDs) has been progressing rapidly in recent years. The combined properties of high efficiency,low noise, and fast speed of SNSPDs permit its applications ranging from long-distance quantum teleportation to moonto-earth optical communications. Here we briefly discussed recent progress of SNSPDs, in particular(1) tungstensilicide SNSPDs,(2) waveguide-integrated SNSPDs, and(3) a few applied demonstrations.展开更多
基金Supported by Guizhou Provincial Department of Education’s Higher Education Scientific Research Project(No.[2022]172)Guizhou Province Science and Technology Plan Project(No.ZK[2022]General022)Universities Key Laboratory of System Modeling and Data Mining in Guizhou Province(No.2023013)。
基金Project supported by the National Natural Science Foundation of China (No. 60372107) and the Hi-Tech Research and Development Program (863) of China (No. 2002AA121068)
文摘This paper proposes a new multitarget constant modulus array structure for code division multiple access (CDMA) systems. The new algorithm for the structure is called pre-despreading and wavelet denoising constant modulus algorithm (D-WD-CMA). In the new algorithm, the pre-despreading is applied to multitarget arrays to remove some multiple access inter- ferences. After that the received signal is subjected to wavelet de-noising to reduce some noise, and used in CMA adaptive iteration for signal separation. Simulation results showed that the proposed algorithm performed better than the traditional CMA algorithm.
文摘The configuration of the novel three-stage L-band erbium-doped fiber amplifier with very large and flat gain and very low noise figure presented in this paper uses the forward ASE (amplified spontaneous emission) from the first section of the EDF (erbium-doped fiber) and the backward ASE from the third section of the EDF (both serve as the secondary pump sources of energy) to pump the second EDF. To improve the pump efficiency, the power of the pump is split into two parts (with a ratio of e.g. 2:7). The characteristics of this L-band EDFA are studied on the basis of the Giles Model with ASE.
文摘Image or video resources are often received in poor condition, mostly with noise or defects making the resources hard to read. We propose an effective algorithm based on digital image inpainting. The mechanism can be used in restoring images or video frames with very high noise or defect ratio (e.g., 90%). The algorithm is based on the concept of image subdivision and estimation of color variations. Noises inside blocks of different sizes are inpainted with different levels of surrounding information. The results showed that an almost unrecognizable image can be recovered with visually good result. The algorithm can be further extended for processing motion picture with high percentage of noise.
基金supported by the Science and Technology Support Project of Sichuan Province of China(Grant No.2013GZX0137)the Fund for Young Persons Project of Sichuan Province of China(Grant No.12ZB017)+2 种基金the National Natural Science Foundation of China(Grant No.61100205)the Project of the Fundamental Research Funds for the Central Universities of China(Grant No.2013RC0307)the Cryptography Basic Development of the National"Twelfth Five-Year Plan" of China on Cryptographic Theory(Grant No.MMJJ201301004)
文摘This work presents two robust quantum secure communication schemes with authentication based on Einstein-Podolsky-Rosen(EPR) pairs, which can withstand collective noises. Two users previously share an identity string representing their identities. The identity string is encoded as decoherence-free states(termed logical qubits), respectively, over the two collective noisy channels, which are used as decoy photons. By using the decoy photons, both the authentication of two users and the detection of eavesdropping were implemented. The use of logical qubits not only guaranteed the high fidelity of exchanged secret message, but also prevented the eavesdroppers to eavesdrop beneath a mask of noise.
基金supported by the National Natural Science Foundation of China(61505141 and 11527808)the National Thousand Talents Plan for Young Professionals
文摘Research of superconducting nanowire singlephoton detectors(SNSPDs) has been progressing rapidly in recent years. The combined properties of high efficiency,low noise, and fast speed of SNSPDs permit its applications ranging from long-distance quantum teleportation to moonto-earth optical communications. Here we briefly discussed recent progress of SNSPDs, in particular(1) tungstensilicide SNSPDs,(2) waveguide-integrated SNSPDs, and(3) a few applied demonstrations.
