A 4 bit/sample transform coder is designed using a psychoacoustically derived noise masking threshold based on the shortterm input spectrum of the signal. The coder has been tested in a formal subjective test involving a wide selection of monophonic audio inputs. The signals used in the test were of 15 kHz bandwidth, sampled at 32 kHz. The bit rate of the resulting coder was 128 kbits/s. The su...

Error-correcting output codes (ECOCs) represent classes with a set of output bits, where each bit encodes a binary classiication task corresponding to a unique partition of the classes. Algorithms that use ECOCs learn the function corresponding to each bit, and combine them to generate class predictions. ECOCs can reduce both variance and bias errors for multiclass classiication tasks when the ...

We propose a unified framework for segment quantization of speech at ultra low bit-rates of 150 bits/sec based on unit-selection principle using a modified one-pass dynamic programming algorithm. The algorithm handles both fixedand variablelength units in a unified manner, thereby providing a generalization over two existing unit selection methods, which deal with ‘single-frame’ and ‘segmental’...

In this paper we evaluated the performance of orthogonal space-time block codes with transmit antenna selection (TAS/OSTBCs) for frequency-flat correlated Rayleigh fading channels. By effective use of the probability density function (pdf), the bit error probability (BEP) for binary phase shift keying (BPSK) and M-ary Quadrature amplitude modulation (M-QAM) is derived first. Further we evaluate...

When communicating at a very-low bit-rate, video coders are unable to preserve high visual quality for all images. A selection of key regions according to human viewing and understanding may therefore be useful: it allows extracting essential features and to code them with a high quality, while the remainder of the image is coarsely transmitted. Such an approach requires a signal decomposition ...

Very low bit-rate video coding using patterns to represent moving regions in macroblocks exhibits good potential for improved coding efficiency. Recently an Arbitrary Shaped Pattern Selection (ASPS) algorithm and its Extended version (EASPS) were presented, that used a dynamically extracted set of patterns, of the two different sizes, based on actual video content. These algorithms, like other ...

Very low bit-rate video coding using patterns to represent moving regions in macroblocks exhibits good potential for improved coding efficiency. Recently an Arbitrary Shaped Pattern Selection (ASPS) algorithm was presented, that used a dynamically extracted set of same sized patterns, which were based on actual video content. This algorithm however, like other pattern matching algorithms failed...

In the binary evolutionary optimization framework, two mutation operators are theoretically investigated. For both the standard mutation, in which all bits are ipped independently with the same probability, and the 1-bit-ip mutation, which ips exactly one bit per bitstring, the statistical distribution of the rst hitting times of the target are thoroughly computed (expectation and variance) up ...

A modified version of the multilevel coded modulation scheme of Imai & Hirakawa is presented and analyzed. In the transmitter, the outputs of the component codes are bit interleaved prior to mapping into 8-PSK channel signals. A multistage receiver is considered, in which the output amplitudes of the Gaussian channel are soft limited before entering the second and third stage decoders. Upper bo...