消除病毒变形的零转换技术

计算机病毒变形技术的出现产生了大量的变形病毒,传统的病毒检测系统在变形病毒检测方面不尽人意。针对该现象,提出了一种消除病毒变形的零转换技术,其中包括消除病毒变形技术常用的垃圾代码的插入、变量重命名、等价语句替换、跳转指令的利用和语句重排等变形转换方法。实验结果表明,该技术能从很大程度上降低病毒变形的个数,程序语句可能出现的平均转换形式个数从转换前的1043降低到108,达到了提高病毒检测系统性能的目的。

用STUFF函数编制简捷、高效的打印程序

在数据库语言中,用打印输出命令编制程序,编制调试工作量大,效率相对比较低。笔者在实践中发现,用 STUFF 函数可使打印报表程序的编制简洁、高效。STUFF(〈字串表达式1〉,〈数值表达式1〉,〈数值表达式2〉.〈字串表达式2〉)函数是字符串替换函数,用字串2替换字串J中的子串,该子串在子串1 的起始位置由数值表达式1决定,长度由数值表达式2决定。把报表的一行(空表)赋给字串表达式1。

上下文无关语言的同步运算及其性质

针对上下文无关语言,引入了语言的可重复序列的依赖运算和同步运算,分析了两种运算的性质、特点,给出了可重复序列的依赖表达式、同步串约束表达式;提出了同步串约束上下文无关语言,给出了该类语言的构造规则:对于字母表上的同步串约束上下文无关语言L,都是由该字母表上的一个正规语言R与该正规语言R中某些可重复序列之间的依赖约束所形成的;证明了同步串约束上下文无关语言与同步串约束表达式所描述的语言等价,且该类语言是上下文无关语言的真子集。

Derivation of Multiverse from Universal Wave Function Interpretation of String Theory

The multiverse is a hypothesis created to solve certain problems in cosmology. Currently, this scheme is still largely ad hoc, rather than derived from fundamental laws and principles. Because of this, the predictive power of this theory is rather limited. Furthermore, there are concerns that this theory will make it impossible to calculate some measured quantities, such as the masses of quarks and the electron. In this paper, we will show that a new development in string theory, the universal wave function interpretation of string theory, provides a way to derive the mathematical expression of the multiverse. We will demonstrate that the Weyl invariance existing in string theory indicates that our observed universe is a projection from a hologram. We will present how the laws of physics can be derived from this fact. Furthermore, we suggest it may also provide a way to calculate the masses of fundamental particles such as quarks and the electron.