北方光缆温度特性问题的解决方案

为了克服架空光缆束管的伸缩及直埋光缆的冻害对光缆传输的影响,对因温度变化使架空光缆束管伸缩引起的光缆故障进行了研究和剖析,以让束管中的光纤自由伸缩为原则给出了多种有效的解决办法;直埋光缆因温度原因引起的故障主要表现为过路顶管冻害故障,并首次阐述了直埋光缆冻害故障多发生在初春而不是冬季的原因,提出了用蒸汽法以及用海绵橡胶子管代替塑料子管方法解决直埋光缆冻害故障,并计算了海绵橡胶子管替代法可实现的经济效益。     

用于下线间无线序光缆割接的旧路由光缆法

通过测试旧路由光缆,查找出旧路由光缆同机房侧光缆连接的光纤色谱线序信息,用于处理下线间无线序光缆割接难题。实践证明采用旧路由光缆法进行下线间无线序光缆割接可确保割接完毕后光路、线路直接通,两端光纤无需倒换,并且可按重要线路优先原则进行光缆路由变更。此外,旧路由光缆法还可用于处理光缆故障。     

从线性时序逻辑公式到自动机的转换算法

To combat the well-known state-space explosion problem in Propositional Linear Temporal Logic (PLTL) model checking, a novel algorithm capable of translating PLTL formulas into Nondeterministic Automata (NA) in an efficient way is proposed. The algorithm firstly transforms PLTL formulas into their non-free forms, then it further translates the non-free formulas into their Normal Forms (NFs), next constructs Normal Form Graphs (NFGs) for NF formulas, and it finally transforms NFGs into the NA which accepts both finite words and infinite words. The experimental data show that the new algorithm reduces the average number of nodes of target NA for a benchmark formula set and selected formulas in the literature, respectively. These results indicate that the PLTL model checking technique employing the new algorithm generates a smaller state space in verification of concurrent systems.     

将“形散神聚”的复习策略应用于高三二轮复习——以“基本不等式”专题复习为例

高三一轮章节复习与二轮专题复习是一个相辅相成的过程,一轮复习侧重于基础性和全面性,二轮复习侧重于综合性与创新性.笔者认为,针对一轮复习中出现的重、难点问题,可以在二轮复习中采取“形散神聚”的复习策略进行专题复习,本文以“基本不等式”专题教学设计为例进行说明.     

一种基于区间时序逻辑模型检测的入侵检测算法

Model checking based on linear temporal logic reduces the false negative rate of misuse detection. However, linear temporal logic formulae cannot be used to describe concurrent attacks and piecewise attacks. So there is still a high rate of false negatives in detecting these complex attack patterns. To solve this problem, we use interval temporal logic formulae to describe concurrent attacks and piecewise attacks. On this basis, we formalize a novel algorithm for intrusion detection based on model checking interval temporal logic. Compared with the method based on model checking linear temporal logic, the new algorithm can find unknown succinct attacks. The simulation results show that the new method can effectively reduce the false negative rate of concurrent attacks and piecewise attacks.