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从位置参数入手直接建立圆点曲线方程
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作者 王允地 郑晨升 詹启贤 《机械科学与技术》 CSCD 北大核心 1996年第2期217-220,共4页
根据刚体四个有限位置的位移参数及点四位置共圆的等圆周角条件,列出了复极矢量等式.在刚体坐标系上,直接导出了圆点曲线方程,并给出圆点坐标的具体算法.
关键词 位置参数 圆点曲线 复极矢量 四杆机构
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类射影对应圆束法构成重虚圆点四次曲线 被引量:1
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作者 边欣 吴红丹 《工程图学学报》 CSCD 2000年第1期10-13,共4页
定义了类射影对应圆束的概念,证明了类射影对应圆束的交点轨迹 是重虚圆点四次曲线,给出了具体的实例及由计算机绘制的图形。
关键词 类射影对应圆束 重虚圆点四次曲线 计算机绘图
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铰链点可互换的近似直线机构综合方法及解域研究 被引量:5
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作者 尹来容 黄娟 +2 位作者 胡林 刘鑫 张志勇 《中国机械工程》 EI CAS CSCD 北大核心 2016年第24期3351-3354,共4页
基于拐点圆极点理论,给出了一种可以综合出无穷多铰链四杆近似直线机构的方法。用解析法证明了该方法综合出近似直线机构的一个连架杆的固定铰链点和对应动铰链点可以互换,铰链点互换前后得到的两个机构具有相同的鲍尔点和直线方向,另... 基于拐点圆极点理论,给出了一种可以综合出无穷多铰链四杆近似直线机构的方法。用解析法证明了该方法综合出近似直线机构的一个连架杆的固定铰链点和对应动铰链点可以互换,铰链点互换前后得到的两个机构具有相同的鲍尔点和直线方向,另外一个连架杆不变。推导了综合曲柄摇杆直线机构的公式,并绘制了曲柄摇杆机构解域图。计算示例表明该方法简单有效,能迅速综合出曲柄摇杆直线机构,且综合出的机构动铰链点和固定铰链点可互换。所得到的近似直线机构为实际工程应用提供了更多选择。 展开更多
关键词 直线机构 拐点圆 圆点曲线 机构综合
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四位置刚体导引曲柄滑块机构的设计 被引量:2
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作者 熊滨生 张明成 李秀明 《郑州大学学报(工学版)》 CAS 2004年第2期84-86,共3页
通过作出布尔梅斯特圆心曲线、圆点曲线后,根据动力学要求γmin>40°~50°,对曲柄滑块机构进行了设计,求出拐点圆,并得出滑点、导路倾角、拐点圆之间的关系.滑块铰接点B1的位置与滑块导路倾角β有关,而拐点圆K1与滑块导路... 通过作出布尔梅斯特圆心曲线、圆点曲线后,根据动力学要求γmin>40°~50°,对曲柄滑块机构进行了设计,求出拐点圆,并得出滑点、导路倾角、拐点圆之间的关系.滑块铰接点B1的位置与滑块导路倾角β有关,而拐点圆K1与滑块导路倾角β无关;设计时可适当调整滑块导路倾角β而拐点圆不变,则点B1位置在拐点圆K1上作出相应变化,以满足设计要求.对于计算实例,当A取值<-17时,不能得到圆心曲线上的点,与布尔梅斯特圆心曲线的理论相符合,即对于任意给定连杆平面四个相关位置,连杆运动平面上只能找到一些与之相应的圆心点. 展开更多
关键词 四位置刚体导引 曲柄滑块机构 导路倾角 圆心曲线 圆点曲线 相关点 平面连杆机构
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再现周期函数的平面六杆机构综合
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作者 刘德庸 黄真 《机械科学与技术》 CSCD 北大核心 1992年第4期51-54,共4页
关键词 周期函数 六杆机构 圆点曲线
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TWO FAST ALGORITHMS FOR COMPUTING POINT SCALAR MULTIPLICATIONS ON ELLIPTIC CURVES 被引量:1
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作者 YouLin WenQiaoyan XuMaozhi 《Journal of Electronics(China)》 2004年第5期366-375,共10页
The key operation in Elliptic Curve Cryptosystems(ECC) is point scalar multiplication. Making use of Frobenius endomorphism, Muller and Smart proposed two efficient algorithms for point scalar multiplications over eve... The key operation in Elliptic Curve Cryptosystems(ECC) is point scalar multiplication. Making use of Frobenius endomorphism, Muller and Smart proposed two efficient algorithms for point scalar multiplications over even or odd finite fields respectively. This paper reduces the corresponding multiplier by modulo Υk-1 +…+Υ+ 1 and improves the above algorithms. Implementation of our Algorithm 1 in Maple for a given elliptic curve shows that it is at least as twice fast as binary method. By setting up a precomputation table, Algorithm 2, an improved version of Algorithm 1, is proposed. Since the time for the precomputation table can be considered free, Algorithm 2 is about (3/2) log2 q - 1 times faster than binary method for an elliptic curve over 展开更多
关键词 Frobenius endomorphism Frobenius expansion Point scalar multiplication Binary method
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SPEED UP RATIONAL POINT SCALAR MULTIPLICATIONS ON ELLIPTIC CURVES BY FROBENIUS EQUATIONS
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作者 You Lin Zhao Junzhong Xu Maozhi 《Journal of Electronics(China)》 2006年第1期58-63,共6页
Let q be a power of a prime and φ be the Frobenius endomorphism on E(Fqk), then q = tφ - φ^2. Applying this equation, a new algorithm to compute rational point scalar multiplications on elliptic curves by finding... Let q be a power of a prime and φ be the Frobenius endomorphism on E(Fqk), then q = tφ - φ^2. Applying this equation, a new algorithm to compute rational point scalar multiplications on elliptic curves by finding a suitable small positive integer s such that q^s can be represented as some very sparse φ-polynomial is proposed. If a Normal Basis (NB) or Optimal Normal Basis (ONB) is applied and the precomputations are considered free, our algorithm will cost, on average, about 55% to 80% less than binary method, and about 42% to 74% less than φ-ary method. For some elliptic curves, our algorithm is also taster than Mǖller's algorithm. In addition, an effective algorithm is provided for finding such integer s. 展开更多
关键词 Elliptic curve Point scalar multiplication Frobenius equation q-ary method φ-polynomial
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CONDITIONAL FACTORIZATION BASED ON LATTICE THEORY FOR -INTEGERS
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作者 Zheng Yonghui Zhu Yuefei 《Journal of Electronics(China)》 2008年第2期254-257,共4页
In this paper,the integer N = pkq is called a <k,1>-integer,if p and q are odd primes with almost the same size and k is a positive integer. Such integers were previously proposed for various cryptographic appli... In this paper,the integer N = pkq is called a <k,1>-integer,if p and q are odd primes with almost the same size and k is a positive integer. Such integers were previously proposed for various cryptographic applications. The conditional factorization based on lattice theory for n-bit <k,1>-integersis considered,and there is an algorithm in time polynomial in n to factor these integers if the least significant 「((2k-1)n)/((3k-1)(k+1))」bits of p are given. 展开更多
关键词 LLL-algorithm Number field sieve Elliptic curve method
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DEFENSE AGAINST COLLUSION SCHEME BASED ON ELLIPTIC CURVE CRYPTOGRAPHY FOR WIRELESS SENSOR NETWORKS
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作者 Cheng Hongbing Huang Xiao Yang Geng 《Journal of Electronics(China)》 2009年第5期651-658,共8页
Wireless Sensor Networks (WSNs) are being deployed for a wide variety of applications and the security problems of them have received considerable attention. Considering the limitations of power, computation capabilit... Wireless Sensor Networks (WSNs) are being deployed for a wide variety of applications and the security problems of them have received considerable attention. Considering the limitations of power, computation capability and storage resources, this paper proposed an efficient defense against collusion scheme based on elliptic curve cryptography for wireless sensor networks in order to solve the problems that sensor node-key leaking and adversaries make compromised nodes as their collusions to launch new attack. In the proposed scheme, the group-key distribution strategy is employed to compute the private key of each sensor node, and the encryption and decryption algorithms are constructed based on Elliptic Curve Cryptography (ECC). The command center (node) only needs to broadcast a controlling header with three group elements, and the authorized sensor node can correctly recover the session key and use it to decrypt the broadcasting message. Analysis and proof of the proposed scheme's efficiency and security show that the proposed scheme can resist the k-collusion attack efficiently. 展开更多
关键词 Wireless Sensor Networks (WSNs) COLLUSION Elliptic Curve Cryptography (ECC) Security
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Special automorphisms on Shimura curves and non-triviality of Heegner points 被引量:1
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作者 CAI Li LI YongXiong WANG ZhangJie 《Science China Mathematics》 SCIE CSCD 2016年第7期1307-1326,共20页
We define the notion of special automorphisms on Shimura curves. Using this notion, for a wild class of elliptic curves defined over Q, we get rank one quadratic twists by discriminants having any prescribed number of... We define the notion of special automorphisms on Shimura curves. Using this notion, for a wild class of elliptic curves defined over Q, we get rank one quadratic twists by discriminants having any prescribed number of prime factors. Finally, as an application, we obtain some new results on Birch and Swinnerton-Dyer(BSD) conjecture for the rank one quadratic twists of the elliptic curve X_0(49). 展开更多
关键词 Shimura curves Heegner points BSD conjecture
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