Abstra t. We propose a modular approa h to the formal spe i ation of the requirements on embedded systems. In this approa h, requirements on data are spe i ed as invariants on states. Requirements on behaviour are spe i ed assertionally by temporal logi formulae, restri ting the runs of the system. The proposed method is modular, be ause omponents an be spe i ed and analysed in isolation, and t...

Abstra t. In this paper we dis uss how the spe i ation of omponents may be separated from the des ription of the ontext in whi h they are used. There are a number of ways in whi h this might be possible and here we show how to use the te hnique of promotion in Obje t-Z to ombine omponents whi h are spe i ed using pro ess algebras. We dis uss two approa hes, the rst is to separate out the spe i ...

By any historical or cross-sectional standard, the Japanese economic slump from 1992 to 2004 has been quite unusual. The economy that was once regarded as ʻnumber one ̓fell into a state of low growth, falling prices, and chronic banking crises for more than a decade.2 The average growth rate from 1993 to 2003 was just above 1 per cent, in contrast to the average growth rate of 4 per cent between...

This paper dis usses some modeling issues on erning the ommuni ation between goal-dire ted agents. In parti ular, the role of performatives in agent ommuni ation is dis ussed. It is argued that the spe i ation of the e e t of performatives, as pres ribed by FIPA, is sometimes too weak or unrealisti . The alternative, proposed in this paper, suggests a two phase modeling of the e e t of the ommu...

Dilatonic Charged Nariai instantons mediate the nucleation of black hole pairs during extended chaotic in ation. Depending on the dilaton and in aton elds, the black holes are described by one of two approximations in the Lorentzian regime. For each case we nd Euclidean solutions that satisfy the no boundary proposal. The complex initial values of the dilaton and in aton are determined, and the...

In this paper, we present the hallenges for model he king se urity poli ies in distributed ollaboration systems. The spe i ation of a ollaboration system is onverted to nite state based veri ation models and are veri ed using a model he ker for orre tness and onsisten y. The main hallenge in nite state based model he king is the state spa e explosion. A related problem for verifying se urity pr...

The past years were characterized by unprecedented rises in prices of commodities such as oil or wheat and infl ation rates moved up above the mark of two percent per annum. This led to a revival of the debate whether commodity prices indicate future CPI infl ation and if they can be used as indicator variables for central banks or not. We apply various econometric methods like Granger causalit...

Abstra t| We investigate transparent repli ation of omponents on top of the distributed data spa e ar hite ture Spli e. In Spli e ea h omponent has its own lo al data spa e whi h an be kept small using keys, time stamps and sele tive overwriting. Sin e Spli e appli ations are often safetyriti al, we use two omplementary formal tools to ensure orre tness: the CRL tool set is used for a rapid inv...