The subliminal channel is used to send a secret message to an authorized receiver; the message cannot he discovered by any unauthorized receivers. Designated verifier signature （DVS） provide authentication of a mess...The subliminal channel is used to send a secret message to an authorized receiver; the message cannot he discovered by any unauthorized receivers. Designated verifier signature （DVS） provide authentication of a message, we design a DVS scheme with message recovery mechanism and use it as a subliminal channel. In order to share a message among n users securely and allows t or more users can reconstruct the secret in dynamic groups, we combine both subliminal channel and （t, n） threshold cryptography. Then we proposed a threshold subliminal channel which can convey a subliminal message to a group of users based on message-recovery designated verifier signatures. Reconstructing the subliminal message relies on the cooperation of t or more users in the group and they can verify the validity of the subliminal message. Security and performance analysis show that the proposed scheme is secure and efficient.展开更多
This paper describes the development of a T-year design tide hydrograph （DTH）. A core innovation is that the proposed technique uses the design risk threshold and copula-based conditional risk probability to analyze...This paper describes the development of a T-year design tide hydrograph （DTH）. A core innovation is that the proposed technique uses the design risk threshold and copula-based conditional risk probability to analyze the optimal combination of high waters and low waters of the DTH. A brief description of the method is presented. The in situ semi-diurnal tide data at the coast of Jiangsu Province in China are analyzed. Marginal distributions for high waters and low waters of tides are examined. Furthermore, the joint distributions, condition risk probabilities and risk thresholds of high waters and low waters are presented. Results of the DTH from the proposed method are compared with those from the traditional same-multiple enlarging design approach. It is demonstrated that the proposed method is preferable.展开更多
基金Supported by the National Natural Science Foun-dation of China (60403027)
文摘The subliminal channel is used to send a secret message to an authorized receiver; the message cannot he discovered by any unauthorized receivers. Designated verifier signature （DVS） provide authentication of a message, we design a DVS scheme with message recovery mechanism and use it as a subliminal channel. In order to share a message among n users securely and allows t or more users can reconstruct the secret in dynamic groups, we combine both subliminal channel and （t, n） threshold cryptography. Then we proposed a threshold subliminal channel which can convey a subliminal message to a group of users based on message-recovery designated verifier signatures. Reconstructing the subliminal message relies on the cooperation of t or more users in the group and they can verify the validity of the subliminal message. Security and performance analysis show that the proposed scheme is secure and efficient.
文摘近年来,低功耗广域网络(Low-Power Wide-Area Network,LPWAN)技术在低轨道(Low Earth Orbit,LEO)卫星通信中的应用快速发展。作为LPWAN的典型代表,远距离无线电(Long Range,LoRa)技术因其低功耗与广覆盖特性,成为卫星物联网通信的研究热点。然而,在低信噪比(Signal to Noise Ratio,SNR)条件下,LoRa调制系统的下行链路存在解调误差问题,导致数据传输可靠性显著下降。针对这一问题,通过理论推导与模型分析,研究了Rician信道下LoRa卫星通信系统的误符号率(Symbol Error Rate,SER)性能。通过推导视距(Line of Sight,LOS)路径信号的SER闭式表达式,分析了非视距(Non Line of Sight,NLOS)多径分量对LOS信号解调的干扰机制。在此基础上,提出了一种基于干扰影响阈值的SER优化模型,进一步揭示了低SNR环境下系统的性能极限。仿真结果表明,所推导的闭式表达式能够准确刻画NLOS干扰与LOS信号SER的关联性。优化模型可有效提升低SNR场景下的解调可靠性,为LoRa技术在卫星物联网中的实际部署提供了理论依据与设计指导。
基金financially supported by the Ministry of Water Resources Special Funds for Scientific Research Projects of Public Welfare Industry(Grant No.201001070)Jiangsu Province Science and Technology(Grant Nos.BM2014397 and BM2016031)
文摘This paper describes the development of a T-year design tide hydrograph （DTH）. A core innovation is that the proposed technique uses the design risk threshold and copula-based conditional risk probability to analyze the optimal combination of high waters and low waters of the DTH. A brief description of the method is presented. The in situ semi-diurnal tide data at the coast of Jiangsu Province in China are analyzed. Marginal distributions for high waters and low waters of tides are examined. Furthermore, the joint distributions, condition risk probabilities and risk thresholds of high waters and low waters are presented. Results of the DTH from the proposed method are compared with those from the traditional same-multiple enlarging design approach. It is demonstrated that the proposed method is preferable.
