通信安全是混沌理论最有前景的重要应用之一。为提高系统的安全性能,本文利用多组耦合蔡氏电路设计了一套通信安全系统。首先,基于经典蔡氏电路及其常规改进方法提出了一种新的改进方法,该方法将原电路中电容电压信号作乘法运算后,与原...通信安全是混沌理论最有前景的重要应用之一。为提高系统的安全性能,本文利用多组耦合蔡氏电路设计了一套通信安全系统。首先,基于经典蔡氏电路及其常规改进方法提出了一种新的改进方法,该方法将原电路中电容电压信号作乘法运算后,与原信号一同构成扩展信号,实现经典蔡氏电路的维数扩展。对所提改进电路的理论分析和基于Matlab/Simulink及Multisim的仿真研究表明:该改进蔡氏电路完整保留了蔡氏电路的特性,扩展信号具有更加丰富的混沌现象,可以观测到一个新的四翅蝴蝶吸引子;部分变量桥式耦合技术可以实现对改进电路的良好控制;其次,利用改进电路构成的多组耦合电路合成通信安全系统加密及解密信号,以此掩盖信息实现信息的安全传输,其中加密信号的运算方式相当于系统的二次加密,提高了系统的保密性能;利用一个15 m V的锯齿信号对本文所设计的系统进行测试,结果表明:所设计的系统的传输误差仅为0.5%,本系统具有良好的系统安全性能、灵活性及可扩展性。该改进蔡氏电路通信安全系统的设计原理可以作为利用DSP、集成电路等实现类似通信安全系统的基础,具有极大的深入研究价值。展开更多
Orthogonal variable spreading factor channelization codes are widely used to provide variable data rates for supporting different bandwidth requirements in wideband code division multiple access (WCDMA) systems. A new...Orthogonal variable spreading factor channelization codes are widely used to provide variable data rates for supporting different bandwidth requirements in wideband code division multiple access (WCDMA) systems. A new code match scheme for WCDMA code tree management was proposed. The code match scheme is similar to the existing crowed-first scheme. When choosing a code for a user, the code match scheme only compares the one up layer of the allocated codes, unlike the crowed-first scheme which perhaps compares all up layers. So the operation of code match scheme is simple, and the average time delay is decreased by 5.1%. The simulation results also show that the code match strategy can decrease the average code blocking probability by 8.4%.展开更多
According to the randomness and uncertainty of information in the safety diagnosis of coal mine production system (CMPS), a novel safety diagnosis method was proposed by applying fuzzy logic inference method, which co...According to the randomness and uncertainty of information in the safety diagnosis of coal mine production system (CMPS), a novel safety diagnosis method was proposed by applying fuzzy logic inference method, which consists of safety diagnosis fuzzifier, defuzzifier, fuzzy rules base and inference engine. Through the safety diagnosis on coal mine roadway rail transportation system, the result shows that the unsafe probability is about 0.5 influenced by no speed reduction and over quick turnout on roadway, which is the most possible reason leading to the accident of roadway rail transportation system.展开更多
文摘通信安全是混沌理论最有前景的重要应用之一。为提高系统的安全性能,本文利用多组耦合蔡氏电路设计了一套通信安全系统。首先,基于经典蔡氏电路及其常规改进方法提出了一种新的改进方法,该方法将原电路中电容电压信号作乘法运算后,与原信号一同构成扩展信号,实现经典蔡氏电路的维数扩展。对所提改进电路的理论分析和基于Matlab/Simulink及Multisim的仿真研究表明:该改进蔡氏电路完整保留了蔡氏电路的特性,扩展信号具有更加丰富的混沌现象,可以观测到一个新的四翅蝴蝶吸引子;部分变量桥式耦合技术可以实现对改进电路的良好控制;其次,利用改进电路构成的多组耦合电路合成通信安全系统加密及解密信号,以此掩盖信息实现信息的安全传输,其中加密信号的运算方式相当于系统的二次加密,提高了系统的保密性能;利用一个15 m V的锯齿信号对本文所设计的系统进行测试,结果表明:所设计的系统的传输误差仅为0.5%,本系统具有良好的系统安全性能、灵活性及可扩展性。该改进蔡氏电路通信安全系统的设计原理可以作为利用DSP、集成电路等实现类似通信安全系统的基础,具有极大的深入研究价值。
基金Project(60202005) supported by the National Natural Science Foundation of China
文摘Orthogonal variable spreading factor channelization codes are widely used to provide variable data rates for supporting different bandwidth requirements in wideband code division multiple access (WCDMA) systems. A new code match scheme for WCDMA code tree management was proposed. The code match scheme is similar to the existing crowed-first scheme. When choosing a code for a user, the code match scheme only compares the one up layer of the allocated codes, unlike the crowed-first scheme which perhaps compares all up layers. So the operation of code match scheme is simple, and the average time delay is decreased by 5.1%. The simulation results also show that the code match strategy can decrease the average code blocking probability by 8.4%.
基金Project(2006BAK04B0302)supported by the National Science and Technology Pillar Program during the 11th Five-year Plan of China
文摘According to the randomness and uncertainty of information in the safety diagnosis of coal mine production system (CMPS), a novel safety diagnosis method was proposed by applying fuzzy logic inference method, which consists of safety diagnosis fuzzifier, defuzzifier, fuzzy rules base and inference engine. Through the safety diagnosis on coal mine roadway rail transportation system, the result shows that the unsafe probability is about 0.5 influenced by no speed reduction and over quick turnout on roadway, which is the most possible reason leading to the accident of roadway rail transportation system.
