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给出了代数免疫阶,汉明重量,非线性度和相关免疫阶之间的关系,得出构造密码学综合性质较优的布尔函数的一种思想,给出构造方法,并给出了实例. 相似文献
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Liu Yongcai 《上海大学学报(英文版)》1998,2(2):144-147
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本文首先证明了布尔减、布尔除与非运算构成完备集,并根据布尔减、布尔除与非运算的运算规则和性质,从与或非代数系统中的最小项、最大项展开式出发,推导了任意逻辑函数在减除非代数系统中的标准DOS(减之除)和标准SOD(除之减)展开式。最后举例说明了二个代数系统中展开式之间的转换。本文的工作对进一步完善布尔代数的四则运算理论具有一定的意义。 相似文献
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ABSTRACTBackground and Context: Learners struggle with conceptual understanding of introductory programming concepts such as variables, expressions, and loops.Objective: We examine whether and how designed activities for conceptual exploration support preliminary engagement with and learning of foundational and often hard-to-grasp programming concepts for students in grades 6–8.Method: Drawing on principles from dynamic mathematics, we developed a suite of non-programming digital and unplugged activities embedded in a curriculum before students engage in Scratch block-based programming. We conducted empirical research in three middle school classrooms in diverse urban US schools and examined student performance through mixed qualitative and quantitative methods.Findings: Learning gains were significant and not predicted by grade, gender or prior academic preparation. Free-choice projects of students showed statistically greater (correct) use of key concepts compared to those not in the study.Implications: Our work demonstrates the promise of novel approaches such as interactive non-programming activities for deeper understanding of programming concepts. 相似文献
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INTRODUCTION A variety of desirable criteria for functions have been identified: balancedness, local and global ava-lanche characteristics, high nonlinearity, etc. These properties are also very important for cryptographic purpose. Obtaining optimal tradeoffs among so many properties is hard. If we take into account more crite-ria, it is more difficult to generate Boolean functions satisfying those properties purely by constructive algebraic methods. How to construct Boolean func-tions … 相似文献
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粘贴模型是目前DNA计算模型中的主要模型之一,该模型采用单、双链混合型DNA分子进行编码,具有在生物操作过程中不需要DNA链的延伸、无须生物酶的作用以及DNA链可重复使用等优点,因而倍受学者们的关注;介绍粘贴模型的数据表示方法;给出了利用粘贴模型表示布尔矩阵,实现了布尔和运算,充分反映了DNA计算的巨大并行性。 相似文献
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布尔运算是实体造型的常用工具之一,但在设计实践中,设计师不太习惯于使用其中的布尔交运算。本文探讨了布尔交运算的实质、优点和适用场合,提出了一种造型设计的新思路。 相似文献
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使用一种新的逻辑函数化简的图形法,使得化简5变量及以上的逻辑函数变得简单、直观、容易操作。这种对称方形图法化简方法采用方形图的对称性并在格雷码中找到一种既能满足最小项逻辑相邻,又能保证最小项对称相邻并符合方形图的对称性质的编码。化简过程则是根据方形图的对称性找出所有相邻的最小项,从而消掉n个变化的量,保留(m-n)个不变的量,最后将输出结果表示为与或式得到最终结果。这种化简方法对于任意变量的逻辑函数都适用并且可以将复杂度减少到最小,清晰度提升到一定的高度。 相似文献