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CDMA体制长周期测距码的编码方法与相关特性 被引量:2
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作者 任亚安 马文平 王新梅 《西安电子科技大学学报》 EI CAS CSCD 北大核心 2003年第3期331-334,共4页
通过对测距伪随机码的常用序列及性能研究,针对采用码分多址体制的卫星定位系统的特点,定义了长周期测距码,分析了其相关性的特点和编码的基本要求,并提出了一种编码方案,给出了局部互相关值的最大值的理论下限和部分仿真数据.这些结论... 通过对测距伪随机码的常用序列及性能研究,针对采用码分多址体制的卫星定位系统的特点,定义了长周期测距码,分析了其相关性的特点和编码的基本要求,并提出了一种编码方案,给出了局部互相关值的最大值的理论下限和部分仿真数据.这些结论同样适用于长周期的直接扩频序列. 展开更多
关键词 CDMA 长周期测距 伪随机 分多址 局部相关性 精确码
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“双码”架构下的云存储多节点修复协作编码
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作者 谢显中 黄倩 王柳苏 《通信学报》 EI CSCD 北大核心 2015年第S1期1-8,共8页
针对云存储中现有多节点失效修复模型的不足,给出了一种可以对多个系统节点或冗余节点同时修复的多节点协作的精确修复码,证明了其存在性,并且将此修复码与具有健康节点协作的MDS双码架构模型相结合,以达到对多节点修复的同时,降低修复... 针对云存储中现有多节点失效修复模型的不足,给出了一种可以对多个系统节点或冗余节点同时修复的多节点协作的精确修复码,证明了其存在性,并且将此修复码与具有健康节点协作的MDS双码架构模型相结合,以达到对多节点修复的同时,降低修复带宽、修复链路数和单个中间节点需要处理的数据量。通过数值仿真结果表明,本模型与修复方案在以上3个方面具有较大改进,尤其削弱了修复时中间节点的负荷,且随着云存储中节点数量的增多,本方案的优势更加明显。 展开更多
关键词 云存储 多节点协作精确修复 协作修复 双极大距离可分模型
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Hepatitis B virus pre-S2 start codon mutations in Indonesian liver disease patients 被引量:3
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作者 Andi Utama Marlinang Diarta Siburian +11 位作者 Ismail Fanany Mariana Destila Bayu Intan Rama Dhenni Tri Shinta Kurniasih Syafruddin AR Lelosutan Wenny Astuti Achwan Nasrul Zubir Arnelis Benyamin Lukito Irawan Yusuf Laurentius Adrianus Lesmana Ali Sulaiman 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第38期5418-5426,共9页
AIM: To identify the prevalence of pre-S2 start codon mutations and to assess their association with liver disease progression. METHODS: The mutations were identified by direct sequencing from 73 asymptomatic carriers... AIM: To identify the prevalence of pre-S2 start codon mutations and to assess their association with liver disease progression. METHODS: The mutations were identified by direct sequencing from 73 asymptomatic carriers, 66 chronic hepatitis (CH), 66 liver cirrhosis (LC) and 63 hepatocellular carcinoma (HCC) patients. Statistical significances were determined using Fisher's exact test, χ 2 test, and t -test analyses whenever appropriate. Pre-S mutation as a risk factor for advanced liver disease was estimated by unconditional logistic regression model adjusted with age, sex, and hepatitis B e antigen (HBeAg). P < 0.05 was considered significant. RESULTS: Mutation of the hepatitis B virus (HBV) pre-S2 start codon was found in 59 samples from 268 subjects (22.0%), with higher prevalence in patients with cirrhosis 27/66 (40.9%) followed by HCC 18/63 (28.6%), chronic hepatitis 12/66 (18.2%) and asymptomatic carriers 2/73 (2.7%) (P < 0.001). Logistic regression analysis showed that pre-S2 start codon mutation was an independent factor for progressive liver disease. Other mutations, at T130, Q132, and A138, were also associated with LC and HCC, although this was not statistically significant when adjusted for age, sex, and HBeAg. The prevalence of pre-S2 start codon mutation was higher in HBV/B than in HBV/C (23.0% vs 19.1%), whilst the prevalence of T130, Q132, and A138 mutation was higher in HBV/C than in HBV/B. The prevalence of pre-S2 start codon mutation was higher in LC (38.9%) and HCC (40.0%) than CH (5.6%) in HBeAg(+) group, but it was similar between CH, LC and HCC in HBeAg(-) group. CONCLUSION: Pre-S2 start codon mutation was higher in Indonesian patients compared to other Asian countries, and its prevalence was associated with advanced liver disease, particularly in HBeAg(+) patients. 展开更多
关键词 Hepatitis B virus Pre-S2 start codon Liver disease Hepatitis B e antigen seroconversion Indonesia
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On Sequential Composition of Precise Zero-Knowledge
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作者 丁宁 谷大武 《Journal of Shanghai Jiaotong university(Science)》 EI 2010年第1期43-48,共6页
Precise zero-knowledge was introduced by Micali and Pass in STOC'06.This notion captures the idea that the view of any verifier in interaction can be reconstructed in almost time.Pass also obtained a sequential co... Precise zero-knowledge was introduced by Micali and Pass in STOC'06.This notion captures the idea that the view of any verifier in interaction can be reconstructed in almost time.Pass also obtained a sequential composition lemma for precise zero-knowledge protocols.However,this lemma doesn't provide tight precisions for composed protocols.In this paper we further obtain a sequential composition lemma for a subclass of precise zero-knowledge protocols,which all satisfy a property:their simulators use the code of verifier in almost the black-box way.We call such subclass emulated black-box zero-knowledge protocols.Our lemma provides better precisions for sequential composition of such protocols. 展开更多
关键词 CRYPTOGRAPHY ZERO-KNOWLEDGE precise zero-knowledge
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