The low-temperature rotational (de-) excitation of C3 (X 1 g ) by collisions with He ( S ) is studied using an ab initio potential energy surface (PES). This PES has been calculated using the singleand double-excitation coupledcluster approach with noniterative perturbational treatment of triple excitations [CCSD(T)] and the augmented correlation-consistent triplebasis set (aug-cc-pVTZ) with bo...

Locally testable codes are error-correcting codes for which membership of a given word in the code can be tested probabilistically by examining it in very few locations. A linear code C ⊆ F2 is called sparse if dim(C) = O(log(n)). We say that a code C ⊆ F2 is -biased if all nonzero codewords of C have relative weight in the range ( 1 2 − , 1 2 + ), where may be a function of n. Kaufman and Suda...

video coding, low bit rate, morphological segmentation, wavelet A video coding/decoding system for applications requiring low bit rate has been developed. This coding scheme uses an intraframe coder for the initial frame in the video sequence and subsequent frames are coded using an interframe coding method. A wavelet-based technique is used for intraframe coding. For interframe coding, displac...

Postfilters are used in speech decoders to improve speech quality by preserving formant information and reducing noise in the valley regions. In this thesis, a new adaptive least-squares LPC-based time-domain postfilter is presented to overcome problems presented in the conventional LPC-based time-domain postfilter. Conventional LPC-based time-domain postfilter [4] produces an unpredictable spe...

Over the last decade major advances have been made in speech coding technology which is now widely used in international, digital mobile and satellite networks. The most recent techniques permit telephone network quality speech transmission at 8 kbit/s, but there are still demands for even lower rates and more flexible, good quality coding techniques for various network applications. This paper...

We present a new Trellis Coded Vector Residual Quantizer (TCVRQ) that combines trellis coding and vector residual quantization. We introduce new methods for computing quantization levels and experimentally analyze the performances of our TCVRQ in the case of speech coding at very low bit rates. The results obtained show that transparent quantization of Linear Prediction (LP) parameters can be p...

In this paper, we generalize the standard blockwise linear predictive (LP) coding by introducing low-pass filtering and downsampling of the LPC vectors at the encoder side, accompanied by interpolation at the decoder. Several concepts in LP coding, such as overlapping frames, interpolation and long analysis frames, can be described in the proposed framework. We also note that the proposed metho...

Networked embedded control systems are present almost everywhere. A recent trend is to introduce radio communication in these systems to increase mobility and flexibility. Network nodes, such as the sensors, are often simple devices with limited computing and transmission power and low storage capacity, so an important problem concerns how to optimize the use of resources to provide sustained o...

In this paper, intelligent compression techniques to allow transmission of text and image data over low bit rate channels are proposed. For text, a compression technique for English language text is presented. Compression is carried out by deleting characters that are not necessary for comprehension by a human reader. Decompression is carried out on a sentence by sentence basis using a database...

This paper presents a method for fast encoding and decoding of image sequences based on fractal coding theory and the hybrid coding concept. The DPCM-loop accounts for statistical dependencies of natural image sequences in temporal direction. Those regions of the original image where the prediction, i.e. motion estimation and compensatio, fails are encoded using an advanced fractal coding schem...