We use a combination of three techniques for the specification of processes, data and time: CSP, Object-Z and Duration Calculus. Whereas the combination of CSP and Object-Z is well established by the work of C. Fischer [2, 3], the integration with Duration Calculus is new. The combination is used to specify parts of a novel case study on radio controlled railway crossings.

We report the discovery of the most distant known AGN, the radio galaxy TN J0924−2201 at z = 5.19. The radio source was selected from a new sample of ultra–steep spectrum (USS) sources, has an extreme radio spectral index α 365MHz = −1.63, and is identified at near–IR wavelengths with a very faint, K = 21.3± 0.3 object. Spectroscopic observations show a single emission line at λ ∼ 7530 Å which ...

A candidate radio-loud broad absorption line quasar (RLBAL) has been reported by Becker et al. (1997). We present JHK observations of this object and three other radio-detected BALs taken with the new Michigan-Dartmouth-MIT/Ohio State/Aladdin IR Camera (MOSAIC) on the KPNO 4-meter. The candidate RLBAL J1556+3517 has B?K=6.63, redder than all but one or two known z>1 quasars. This strongly sugge...

In cognitive radio networks (CRN), resource should dynamically be assigned to the users with respect to sensed radio atmospheres. Many works has been done for dynamic allocation but it is not practically easy because the secondary network is very difficult to know the right knowledge of dynamic radio atmospheres in CRN. In this object we study the different methods of dynamic resource allocatio...

We present multi-frequency radio continuum VLBI observations of the gravitational lens system B0218+357 carried out using a global VLBI network and the VLBA. The source has been observed with resolutions from 0.2 mas to 5 mas and displays interesting structure. The spectral properties of various components show that the lensed object is a standard flat spectrum radio source which has many self-...

We provide a brief overview over the development of software-defined or reconfigurable radio systems. The need for softwaredefined radios is underlined and the most important notions used for such reconfigurable transceivers are thoroughly defined. The role of standards in radio development is emphasized and the usage of transmission mode parameters in the construction of software-defined radio...

We present and discuss observations made with MERLIN and VLBI at 1.7 and 5 GHz of the two CSS quasars 3C 43 and 3C 298. They show quite different morphologies, the former being a very distorted triple radio source, the latter a small FRII type object. Relativistic effects and structural distortions are discussed. Source ages are evaluated to be of the order of ≈105 years, therefore 3C 43 and 3C...

The Software Communications Architecture (SCA), a mandatory specification for Software Radio implementations by the Joint Tactical Radio System (JTRS), defines a Common Object Request Broker Architecture (CORBA) based component model for building portable applications in a heterogeneous environment. The Object Management Group’s (OMG) CORBA is an accepted architecture for distributed systems th...

A remarkable correlation between the Hα emission line and the radio behaviour of LS I+61◦303 over its ∼4 yr modulation is discovered. The radio outburst peak is shifted by a quarter of the ∼4 yr modulat ion period (about 400 days) with respect to the equivalent width of the Hα emission line variability. The onset of the LS I+61◦303 radio outbursts varies in phase with the changes of the Hα emis...