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介绍了国际质量体系ISO90 0 2在公路建设中国际化、科学化、规范化的运作机理及其重要性 相似文献
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This paper proposes an identity-based encryption scheme with the help of bilinear pairings, where the identity information of a user functions as the user's public key. The advantage of an identity-based public key system is that it can avoid public key certificates and certificate management. Our identity-based encryption scheme enjoys short ciphertexts and provable security against chosen-ciphertext attack (CCA). 相似文献
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为减小水上应急救援定位设备完成触发报警的耗时,提升设备在无先验信息冷启动情况下的定位效率,提出一种针对北斗三号B2a信号的捕获方法,利用匹配滤波器(Partial Matched Filters, PMF)对信号直接数字下变频,采用单边带捕获方法消除B2a信号自相关函数多峰特性,通过匹配相关结合快速傅里叶变换(Fast Fourier Transform, FFT),将码相位-多普勒频移的二维搜索降为一维的频率并行搜索,减少捕获时间。通过推导PMF长度和FFT点数对捕获性能的影响,分析相关损失与多普勒频移和相关器长度的关系,提出参数选择建议。结果表明:在信噪比-30 dB的情况下,仍可获得明显的最大相关峰,顺利完成对信号的捕获;与传统并行码相位搜索方法相比,该方法降低了对采样率的要求,有效减少硬件资源消耗、缩短捕获时间、提高捕获灵敏度。 相似文献
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Introduction Inthresholddecryptioncryptosystems,the powertodecryptissharedamongasetofdecryp-tionservers.In2001,D.BonehandM.Franklin proposedapracticalidentity-basedencryption(IBE)schemefromtheweilpairing.Combining thetwoconceptstogether,some“ID-basedthresh-olddecryption”schemeshavebeenconstructed.In suchschemes,anentity'spublickeyisderiveddi-rectlyfromitsidentity.Atrustedthirdparty calledtheprivatekeygenerator(PKG)usesthe masterkeytogenerateprivatekeysforallentities.Eachdecryptionserve… 相似文献
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针对我国既有铁路隧道铺底结构破损严重的现状,在试验研究和数值计算确定隧道铺底结构疲劳危险部位的基础上,采用动力有限元方法计算得到列车动载作用下隧道铺底结构疲劳危险部位的弯拉应力时程曲线,而后根据疲劳累积损伤理论,采用Tepfers的混凝土单对数疲劳方程求出隧道铺底混凝土结构的使用寿命及其损伤度。计算中考虑了10 cm2、0 cm3、0 cm厚素混凝土和20 cm厚钢筋混凝土4种不同的隧道铺底工况,计算结果同模型试验结果的变化规律一致。根据计算结果得出20 cm厚钢筋混凝土铺底结构使用寿命较长的结论。 相似文献
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The only known construction of key-insulated signature (KIS) that can be proven secure in the standard model is based on the
approach of using double signing. That is, the scheme requires two signatures: a signature with a master key and a signature
with the signer’s secret key. This folklore construction method leads to an inefficient scheme. Therefore it is desirable
to devise an efficient KIS scheme. We present the first scheme with such a construction. Our construction derives from some
variations of the Waters’ signature scheme. It is computationally efficient and the signatures are short. The scheme is provably
secure based on the difficulty of computational Diffie-Hellman (CDH) problem in the standard model. 相似文献
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