基于服务器端会话追踪的Web查询服务的研究

在探讨了Web查询服务的典型模型后,论文阐述了服务器端会话追踪机制的实现方式,设计了基于服务器端会话追踪的Web查询服务的典型解决方案。该设计方案可以较为安全地保存和维护客户的上下文信息,可靠地跟踪用户查询所处的状态,有效地实现有状态的Web查询服务。     

网络安全事件的关联分析方法的比较研究

随着当前攻击手段和技术的日益复杂化,一次入侵事件往往需要多个步骤才能完成,这些步骤都是彼此相关的。但是传统的入侵检测集中于检测底层的入侵或异常,所检测到的结果也仅仅是一次完整入侵的一部分,所以不能将不同的报警结合起来以发现入侵的逻辑步骤或者入侵背后的攻击策略。关联分析技术将不同分析器上产生的报警进行融合与关联分析,极大地减少了报警的数量,降低了入侵检测的误报率,并且适当的减少了入侵检测的漏报率。文中在对网络安全事件关联分析方法的系统结构进行分析后,着重介绍了当前比较流行的几种网络安全事件关联分析方法,最后对各种方法进行了比较研究。     

基于可靠性评价的含缺陷核压力管道疲劳寿命预测方法

含缺陷压力管道经缺陷评定合乎使用后,其疲劳寿命的估计具有重要的工程意义。将整个含缺陷压力管道作为一个整体,分析了含缺陷压力管道的疲劳裂纹扩展特点,提出了相应的含缺陷压力管道疲劳寿命的计算过程,并在基于可靠性评价的基础上,给出了核压力管道的可接受失效概率,最终得到了含缺陷核压力管道疲劳寿命预测方法。     

数字电视的条件接收系统

数字电视的兴起使人们能够欣赏到高质量的电视节目,伴随数字电视的成熟,条件接收系统(CAS)得到很好的发展。主要介绍数字电视条件接收系统相关技术的发展、基本功能、安全机制、工作原理及其安全性要求。     

带隔板底水油藏油井临界产量计算公式

本给出了带隔板底水油藏油井的监界产量计算公式，它适用于所有带隔板底水油藏的油井。     

On the complexity of simulating space-bounded quantum computations

This paper studies the space-complexity of predicting the long-term behavior of a class of stochastic processes based on evolutions and measurements of quantum mechanical systems. These processes generalize a wide range of both quantum and classical space-bounded computations, including unbounded error computations given by machines having algebraic number transition amplitudes or probabilities. It is proved that any space s quantum stochastic process from this class can be simulated probabilistically with unbounded error in space O(s), and therefore deterministically in space O(s²).     

Spectral multidomain approximation of elliptic problems with mixed conditions on the interfaces

The multidomain technique for elliptic problems, that allows the fulfillment of the interface conditions by means of a suitable combination of the continuity of the solution and of its normal derivative, is considered. Some choices of this combination are investigated and, in particular, a choice that allows the solution of the multidomain problem through two solutions for each subproblem, is proposed. The scheme has been discretized with a collocation method and some numerical tests are reported. Moreover the method is compared with the more classical Dirichlet/Neumann one as well as with the capacitance matrix method.This research has been supported by a grant from M.P.I. (40%).     

Power Dissipation in Spintronic Devices Out of Thermodynamic Equilibrium

Quantum limits of power dissipation in spintronic computing are estimated. A computing element composed of a single electron in a quantum dot is considered. Dynamics of its spin due to external magnetic field and interaction with adjacent dots are described via the Bloch equations. Spin relaxation due to magnetic noise from various sources is described as coupling to a reservoir. Resulting dissipation of energy is calculated and is shown to be much less than the thermal limit, ∼kT per bit, if the rate of spin relaxation is much slower than the switching rate. Clues on how to engineer an energy efficient spintronic device are provided.     

壳体理论在水压爆破中的应用

在壳体理论的基础上,考虑到薄壳型结构水压爆破的特点,提出了一种新的药量计算公式,并得到了初步实际工程验证.