Point Multiplication on Ordinary Elliptic Curves over Fields of Characteristic Three

 In this paper we investigate the efficiency of cryptosystems based on ordinary elliptic curves over fields of characteristic three. We look at different representations for curves and consider some of the algorithms necessary to perform efficient point multiplication. We give example timings for our operations and compare them with timings for curves in characteristic two of a similar level of security. We show that using the Hessian form in characteristic three produces a point multiplication algorithm under 50 percent slower than the equivalent system in characteristic two. Thus it is conceivable that curves in characteristic three, could offer greater performance than currently perceived by the community. Received: August 9, 2002; revised version: December 5, 2002 Keywords: Elliptic curve cryptography, Hessian form, Characteristic three.     

Operating Characteristic Curves for the Exponential Bayes‐Truncated Test

Operating characteristic (OC) curves are often useful in determining how large a sample is required to detect a specified difference for a particular consumer and producer risk. In this paper, OC curves with Bayes stopping rules for the exponential distribution are developed. Example curves are provided for the sequential and batch testing situations. The power of the test is greater under batch testing. A table illustrates the performance of the plans for stopping at each opportunity in a sample of size 20. Some examples are used to demonstrate the application of the proposed methodology. Copyright © 2004 John Wiley & Sons, Ltd.     

A Simple Point Counting Algorithm for Hessian Elliptic Curves in Characteristic Three

Given an ordinary elliptic curve on Hesse form over a finite field of characteristic three, we give a sequence of elliptic curves which leads to an effective construction of the canonical lift, and obtain an algorithm for computing the number of points. Our methods are based on the study of an explicitly and naturally given 3-isogeny between elliptic curves on Hesse form.     

（60）Co源照射与感光仪曝光的X射线胶片特性曲线比较

比较了60Co源照射与感光仪曝光X射线胶片的特性曲线。两者得到的特性曲线趾部与线性段均吻合较好,这些结果对今后在X射线照相中应用H-D曲线具有参考作用。     

基于性能曲线的冷水机组配置和运行优化

在设计中引入简单有效的计算手段,对冷水机组配置和运行的优化进行节能分析是必要的,本文分析了与冷水机组节能相关的因素,介绍了常用冷水机组典型性能特征,举例分析常用冷水机组COP-PLRC-tc曲线,提出了基于性能曲线的冷水机组配置和优化运行方法,阐述了运用该方法对进行冷水机组配置和运行优化的步骤,最后为采用该方法的应用实例。     

空调VWV系统变频调节特性研究

提出了空调VWV(Variable Water Volume)系统变频调节的控制方案,建立了调节过程的数学模型,对系统的调节品质和能耗进行了分析.     

空间椭圆曲线的插补算法

根据时间分割法的基本思想,提出了一种空间椭圆曲线的插补算法。该算法精度高、速度快,完全满足ＣＮＣ系统插值的实时性要求。     

粉煤灰对粘土导水特性的影响研究

提出了一种在干旱区植树造林新材料技术,通过在粘土中加入不同比例或是经过不同试剂改性的粉煤灰,以增加其比表面积,从而提高导水性能,改进干旱区土壤的毛细引水特性,解决该地区植树造林的水分问题;同时达到对废弃粉煤灰资源再利用的目的.采用比表面积与孔径分布测定仪,扫描电镜,热重分析仪等仪器测试手段对试样进行表征.实验结果表明,粘土中粉煤灰所占比例为20%(质量分数)时,试样的导水效果最好;用盐酸或碳酸钠对添加剂粉煤灰进行改性能够提高粘土的导水能力,并分别在盐酸浓度为0.3mol/L、碳酸钠浓度为0.5mol/L时效果最好.     

多壁碳纳米管/水纳米流体的蓄冷特性研究

目的 探究多壁碳纳米管的浓度、管径以及超声声强对纳米流体的蓄冷特性和换热性能的影响规律。方法 将 5~12 nm、10~20 nm、20~30 nm 3种不同管径的多壁碳纳米管和质量分数为0.05%~0.2%的多壁碳纳米管分别制备成不同的纳米流体样品,并搭建试验台对样品进行蓄冷实验。结果 在质量分数从0.05%变为0.2%时,纳米流体的平均过冷度减小了0.7 ℃,管径由20~30 nm变至5~12 nm时,平均过冷度下降了64.3%;1级超声声强使传热能力提高了5.3%,而4级超声声强使传热能力提高了7.8%。结论 研究表明,多壁碳纳米管浓度的增加及管径的减小,可使纳米流体的换热能力增大,过冷度减小,超声声强对多壁碳纳米管/水纳米流体有强化传热作用。     

脉冲激光击穿水介质特性的实验研究

针对激光击穿水介质过程中的微观及宏观特性研究,利用调QNd：YAG激光聚焦击穿水介质形成激光声源,采用高速摄像机、高频测量水听器对激光击穿水介质过程中的等离子腔体闪光、空泡脉动、近／远场声波特性等综合效应进行了实验测量。实验表明：激光空泡的特征与水动力空化空泡相似;激光声信号强度在光击穿条件下与入射激光能量具有一定的线性关系;声脉冲高频段占声能的主要部分。研究结果可为水下激光加工、激光医学、激光声的研究提供一定的理论和实验支持。     

The Effects of Imposed Learning Curves on Performance Improvements

The results of a recent empirical study aimed at investigating the interacting effects of imposed goals, expressed by a dictated learning pace, and the individual's manual performance are presented. The results reveal that such imposition has an adverse effect when the imposed learning pace is slightly faster than the unpaced learning rate, and has no effect when the imposed pace seems to be too difficult. However, subjects can outperform their learning (progress) curves if they are motivated to do so by other techniques such as an amplified incentive scheme. Several industrial implications derived from this study are discussed.     

直线与曲线的逐点生成算法

首先分析了直线生成算法的现状。论证了单点直线生成算法已无进一步发展的余地。指出了多点直线生成算法是今后的研究方向以及这种算法的主要问题。在比较了各种直线生成算法的计算量的基础上推荐了一个当前最有效的直线生成算法。其次,介绍了圆的逐点生成算法的研究现状。推荐了一个被忽视了的但却有着最小计算量的单点生成圆算法,并指出了其存在的严重错误且进行了纠正。然后,提出了一个新的圆双点生成算法,并对圆的各种逐点生成算法的计算量进行了比较。最后,介绍了逐点生成参数曲线和非参数曲线的两个最新算法。     

Construction of Improved Geometric Goppa Codes from Klein Curves and Klein-like Curves

Linear error-correcting codes, especially Reed-Solomon codes, find applications in communication and computer memory systems, to enhance their reliability and data integrity. In this paper, we present Improved Geometric Goppa (IGG) codes, a new class of error-correcting codes, based on the principles of algebraic-geometry. We also give a reasonably low complexity procedure for the construction of these IGG codes from Klein curves and Klein-like curves, in plane and high-dimensional spaces. These codes have good code parameters like minimum distance rate and information rate, and have the potential to replace the conventional Reed-Solomon codes in most practical applications. Based on the approach discussed in this paper, it might be possible to construct a class of codes whose performance exceeds the Gilbert-Varshamov bound. Received: November 14, 1995; revised version: November 22, 1999     

四次有理Bézier曲线的形状调整

给出了一种基于权因子调整的四次Bézier 曲线形状控制的有效方法。推导出了曲线肩点的两种新的表达式。这两个表达式对曲线权因子的意义进行了较好的解释,很好地反应出权因子变化对曲线肩点位置的影响。基于这两个表达式,推导出了曲线肩点插值某固定点时各权因子的具体取值公式。最后,实例表明此方法能给曲线形状调整带来实用性指导。