6,943 research outputs found
An adaptive quasi harmonic broadcasting scheme with optimal bandwidth requirement
The aim of Harmonic Broadcasting protocol is to reduce the bandwidth usage in
video-on-demand service where a video is divided into some equal sized segments
and every segment is repeatedly transmitted over a number of channels that
follows harmonic series for channel bandwidth assignment. As the bandwidth of
channels differs from each other and users can join at any time to these
multicast channels, they may experience a synchronization problem between
download and playback. To deal with this issue, some schemes have been
proposed, however, at the cost of additional or wastage of bandwidth or sudden
extreme bandwidth requirement. In this paper we present an adaptive quasi
harmonic broadcasting scheme (AQHB) which delivers all data segment on time
that is the download and playback synchronization problem is eliminated while
keeping the bandwidth consumption as same as traditional harmonic broadcasting
scheme without cost of any additional or wastage of bandwidth. It also ensures
the video server not to increase the channel bandwidth suddenly that is, also
eliminates the sudden buffer requirement at the client side. We present several
analytical results to exhibit the efficiency of our proposed broadcasting
scheme over the existing ones.Comment: IEEE International Conference on Informatics, Electronics & Vision
(ICIEV), 2013, 6pages, 8 figure
Superbroadcasting of harmonic oscillators mixed states
We consider the problem of broadcasting quantum information encoded in the
displacement parameter for an harmonic oscillator, from N to M>N copies of a
thermal state. We show the Weyl-Heisenberg covariant broadcasting map that
optimally reduces the thermal photon number, and we prove that it minimizes the
noise in conjugate quadratures at the output for general input states. We find
that from two input copies broadcasting is feasible, with the possibility of
simultaneous purification (superbroadcasting).Comment: 9 pages, 1 figure, revtex4, to appear in the Proceedings of ICQO2006,
Minsk, May 200
Superbroadcasting of continuous variables mixed states
We consider the problem of broadcasting quantum information encoded in the
average value of the field from N to M>N copies of mixed states of radiation
modes. We derive the broadcasting map that preserves the complex amplitude,
while optimally reducing the noise in conjugate quadratures. We find that from
two input copies broadcasting is feasible, with the possibility of simultaneous
purification (superbroadcasting). We prove similar results for purification
(M<=N) and for phase-conjugate broadcasting.Comment: 11 pages, 1 figure, revtex4 style, revised versio
Superbroadcasting of conjugate quantum variables
We consider the problem of broadcasting arbitrary states of radiation modes
from N to M>N copies by a map that preserves the average value of the field and
optimally reduces the total noise in conjugate variables. For N>=2 the
broadcasting can be achieved perfectly, and for sufficiently noisy input states
one can even purify the state while broadcasting--the so-called
superbroadcasting. For purification (i.e. M<=N), the reduction of noise is
independent of M. Similar results are proved for broadcasting with
phase-conjugation. All the optimal maps can be implemented by linear optics and
linear amplification.Comment: 7 pages, 1 eps figures. Accepted for publication on Europhysics
Letter
Decoder of the 48 kbps Audio Coder based on Segmental Sinusoidal Model
The recent technology of the television is implementation the digital system over transmitter, transmission channel and receiver. Therefore, television system in Indonesia is dominated by analog system, that less flexible for system development and communication on digital communication system. So that, it need actions to develop the digital broadcasting system to replace the analog broadcasting system. Audio signal information with high quality would help the television audience to increase the perception of the information displayed. Transmission channel capacity will become limited, while the need of channel communication is increased. The limited channel capacity endorse to save all aspect on the telecommunication system. There are some research on audio signal coding to obtain the lower bit rate for transmission channel usage saving. The audio signal is processed, so that the redundant component can be decreased, then we obtain the simple size of information that reliable to be transmitted. The research aim is coding the audio signal on the low bit rate for saving the channel communication usage for digital television broadcasting. The research will be done is develop an audio signal coder on the low bit rate with the suitable decoder. The decoder consists of the parameters detector, signal synthesizer, and the periodic signal generator. The encoder and the decoder development is implemented using C++ software. The hardware for the simulation process consists of microphone, digital signal processor and the personal computer equiped with sound card for audio signal acquisition
A Low Bit Rate Audio Coder based on Segmental Sinusoidal Model
Audio signal information with high quality would help the television audience to increase the perception of the information displayed. Transmission channel capacity will become limited, while the need of channel communication is increased. The research aim is coding the audio signal on the low bit rate for saving the channel communication usage for digital television broadcasting. The research will be done is develop an audio signal coder on the low bit rate with the suitable decoder. The proposed audio signal coder consists of signal existention detector, period width detector, average amplitude counter, separation of the vibrating and the nonvibrating signal, determination of the period signal and parameters coding. One period signal is coded using sinusoidal model. The decoder consists of the parameters detector, signal synthesizer, and the periodic signal generator. The research results contribution for digital broadcasting is the method developing for decreasing the audio signal rate. So that the communication channel usage can be saved
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