网络安全到你家

对于过程控制以及SCADA系统,如果你一直在犹豫是否有必要解决网络安全问题以及何时去解决这些问题,那么不妨借鉴一下电力行业的经验。该行业目前的一些应用可以被视为模板看待。     

多声道平衡及自动校准技术发展渐入佳境

1960-1970年那段时间被称为立体声的黄金岁月 ，那时要调试并建立一套立体声系统是非常简单的，整个系统只包括一对音箱，一个功放（纯A/V功放或附带收音功能）或纯粹的无线电接收器以及诸如唱片机这类型的音源即可，而设置过程更是简单，只需要连接很少的几根线，再将扬声器放到一个合适的位置就可以了。[编者按]     

Greatest Bisimulations for Binary Methods

In previous work [14] I introduced a generalised notion of coalgebra that is capable of modelling binary methods as they occur in object-oriented programming. An important problem with this generalisation is that bisimulations are not closed under union and that a greatest bisimulation does not exists in general. There are two possible approaches to improve this situation: First, to strengthen the definition of bisimulation, and second, to place constraints on the coalgebras (i.e., on the behaviour of the binary methods). In this paper I combine both approaches to show that (under reasonable assumptions) the greatest bisimulation does exist for all coalgebras of extended polynomial functors.     

病毒——仍是最大的威胁

IT security staff say viruses and worms are still their main headache,even though these dangers areless common in the UK than other countries,according to a new report released last week by analyst Ac-centure.In Accenture's annual Global Information Secur…     

Greatest Factorial Factorization and Symbolic Summation

The greatest factorial factorization (GFF) of a polynomial provides an analogue to square-free factorization but with respect to integer shifts instead to multiplicities. We illustrate the fundamental role of that concept in the context of symbolic summation. Besides a detailed discussion of the basic GFF notions we present a new approach to the indefinite rational summation problem as well as to Gosper's algorithm for summing hypergeometric sequences.