Cognitive Radio (CR) is a new wireless communication and networking paradigm that is enabled by the Software Defined Radio (SDR) technology and the recent change in spectrum regulation policy. As the first commercial application of CR technology, IEEE 802.22 wireless regional area networks (WRAN) aim to offer broadband wireless access by efficiently utilizing the unoccupied TV channels. In this...

The jet of the radio galaxy M87 is misaligned, resulting in a Doppler factor δ ∼ 1 for emission of plasma moving parallel to the jet. This makes the observed fast TeV flares on timescales of tv ∼ 5Rg/c harder to understand as emission from the jet. In previous work, we have proposed a jets-in-a-jet model for the ultra-fast TeV flares with tv ≪ Rg/c seen in Mrk 501 and PKS 2155-304. Here, we sho...

Radio transmissions traditionally use one antenna at the transmitter and one antenna at the receiver. This system is termed Single Input Single Output (SISO). Both the transmitter and the receiver have one RF chain (that's coder and modulator). SISO is relatively simple and cheap to implement and it has been used age long since the birth of radio technology. It is used in radio and TV broadcast...

We present our tracking system for the 1998 Topic Detection and Tracking project (TDT-2). This project addresses multiple sources of information in the form of both text and speech from newswire, radio and television news broadcast programs. Our tracking system is probability based and we successfully solve the problem of score normalization across topics with a simple but e ective solution. Te...

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Media monitoring allows to capture media exposure of people, organizations and other important topics. This paper presents a media monitoring system for Latvian radio and television broadcasts. This system uses an automatic speech recognition (ASR) module to convert audio and video files to text and to extract keywords of interest. The system has been developed in close cooperation with Latvian...

In mobile networks, the provision of rich multimedia services, such as Mobile TV, is considered of key importance. To this end, Multimedia Broadcast/Multicast Service (MBMS)—that was introduced in the Release 6 of Universal Mobile Telecommunication System (UMTS)—is envisaged to play an instrumental role in the proliferation of mobile market. The reason behind the design of MBMS was the need to ...