An efficient rate control algorithm for a wavelet video codec

Rate control plays an essential role in video coding and transmission to provide the best video quality at the receiver's end given the constraint of certain network conditions. In this paper, a rate control algorithm using the Quality Factor (QF) optimization method is proposed for the wavelet-based video codec and implemented on an open source Dirac video encoder. A mathematical model which we call Rate-QF (R - QF) model is derived to generate the optimum QF for the current coding frame according to the target bitrate. The proposed algorithm is a complete one pass process and does not require complex mathematical calculation. The process of calculating the QF is quite simple and further calculation is not required for each coded frame. The experimental results show that the proposed algorithm can control the bitrate precisely (within 1% of target bitrate in average). Moreover, the variation of bitrate over each Group of Pictures (GOPs) is lower than that of H.264. This is an advantage in preventing the buffer overflow and underflow for real-time multimedia data streaming

Central mode and spin confinement near the boundary of the superconducting phase in YBa2Cu3O6.353 (Tc=18 K)

We have mapped the neutron scattering spin spectrum at low-energies in YBa2Cu3O6.353 (Tc=18 K) where the doping ~0.06 is near the critical value (pc=0.055) for superconductivity. No coexistence with long range ordered antiferromagnetism is found. The spins fluctuate on two energy scales, one a damped spin response with a ~2 meV relaxation rate and the other a central mode with a relaxation rate that slows to less than 0.08 meV below Tc. The spectrum mirrors that of a soft mode driving a central mode. Extremely short correlation lengths, 42+-5 Angstrom in-plane and 8+-2 Angstrom along the c direction, and isotropic spin orientations for the central mode indicate that the correlations are subcritical with respect to any second order transition to Neel order. The dynamics follows a model where damped spin fluctuations are coupled to the slow fluctuations of regions with correlations shortened by the hole doping.Comment: 5 pages 4 figures. One figure revised and some text revision. Accepted PRB Rapids February 14, 200

ANTIBODIES TO INFLIXIMAB IN PATIENTS WITH INFLAMMATORY BOWEL DISEASE: CLINICAL AND MOLECULAR TARGETS

Infliximab was the first biological therapy to be approved for use in inflammatory bowel disease (IBD). Similar to other biological therapies, secondary loss of response to infliximab occurs in up to 50% of patients at 1 year follow up. In the case of infliximab, antibodies to infliximab (ATI) are likely to contribute towards secondary loss of response. This PhD thesis aims to identify the associated clinical outcomes of ATI, assess a strategy of infliximab dose escalation (DE) and to identify epitopes on infliximab using phage display. In a retrospective review of 214 patients, ATI were detected in 64% of patients during the first year of infliximab treatment. They were significantly associated with loss of clinical response, reduced infliximab levels and adverse drug reactions. Assessment of infliximab DE in 92 patients with subtherapeutic drug levels, showed it was effective at significantly increasing infliximab levels in those with and without ATI. DE was also associated with a high rate of clinical remission at 6 months. Pooled sera from eight patients with positive ATI and differing clinical outcomes was used for biopanning of two phage display libraries. Three distinct linear epitopes were heavily enriched from a novel whole gene fragment library (GFL), all mapped to complementarity determining regions of infliximab. Using a random peptide library (RPL), three different peptides were enriched. Using Pepsurf, a mimotope prediction programme, three conformational epitopes were predicted using the enriched peptides. One of the predicted epitopes from the RPL overlapped with a linear epitope selected from the GFL. In increasing our understanding of immunogenicity to infliximab, this may lead to an identification of an epitope associated with loss of response, a biomarker, and will help aid treatment decisions when ATI are detected

Pengaruh Teknik Sintesis Terhadap Kualitas Produk Fattyamina Sekunder

Secondary fattyamines has been synthesized by reacting primary fatty amines with acylchlorides and continued with reducing the corresponding secondary fattyamides formed to secondary fattyamines using LiAIH<I'Fatty amines are raw material of natural-based surfactants that can be derived from fatty acids, olefins, or alcohols, of which can be synthesized from natural sources such as palm oil. Conversion of secondary fatty amides to secondary fatty amines was evaluated through the quality of FTIR spectra on wave number of 1639-1645 em' (C=O vibration) and 1544-1555 em" (vibrations of C-H and of secondary amine N-H). Method of synthesis by using closed reflux syncore reactor was better than those of using microwave teflon tubes, and open reflux. The yield of 9 different secondary fatty amines obtainedfrom 5 to 27 replicates by the closed reflux syncore reactor method varied from 17%to 96%

Dynamical Properties of a Haldane Gap Antiferromagnet

We study the dynamic spin correlation function of a spin one antiferromagnetic chain with easy-plane single-ion anisotropy. We use exact diagonalization by the Lancz\H os method for chains of lengths up to N=16 spins. We show that a single-mode approximation is an excellent description of the dynamical properties. A variational calculation allows us to clarify the nature of the excitations. The existence of a two-particle continuum near zero wavevector is clearly seen both in finite-size effects and in the dynamical structure factor. The recent neutron scattering experiments on the quasi-one-dimensional antiferromagnet NENP are fully explained by our results.Comment: 14 pages, SphT/92-135 plain tex with Postscript figures included. Postscipt file available by anonymous ftp at amoco.saclay.cea.fr by get pubs.spht/92-135.ps local_file (290 kb) or get pubs.spht/92-135.ps.Z local_file.Z (compressed - 120 kb

Spin dynamics near the critical doping in weakly-superconducting underdoped YBa2Cu3O6.35 (Tc=18K)

Using neutron scattering we have determined the magnetic structure and fluctuations in the YBa2Cu3O6.35 superconductor (Tc=18 K). The long-range ordered collinear spins of the insulating antiferromagnet are replaced by a commensurate central mode arising from slow, isotropically polarized, short-range spin correlations. The inelastic spectrum up to 30 meV is broad in wave vector and commensurate. In contrast to the the resonance peak of higher Tc superconductors, the spins exhibit a single overdamped spectrum whose rate of relaxation decreases on cooling and saturates at 5 meV below 50 K. As the relaxation rate saturates the quasi-static spin correlations grow and become resolution limited in energy. The spin susceptibility at high temperatures illustrates that the dominant energy scale is set by the temperature. At low temperatures, the scale length is geometric and not linked by velocity to dynamic widths. There is no observable suppression of the spin fluctuations or central mode upon the onset of superconductivity. The spins respond not to coherent charge pairs but to hole doping allowing coexistence of glassy short range spin order with superconductivity. Since the physics of the weakly superconducting system YBCO6.35 must connect continuously with that in more strongly superconducting YBCO6.5, we find that neither incommensurate stripe-like spin modulations nor a well-defined neutron spin resonance are essential for the onset with doping of pairing in a high temperature cuprate superconductor.Comment: 22 pages, 19 figures, accepted for publication in Phys. Rev.

Strength Investigation of Thick Welded T-Joint using Finite Element Modelling

The paper discusses the computation of finite element modelling (FEM) of a thick welded joint as a high load transfer joint. The FEM utilises MSC PATRAN/NASTRAN software programs to predict and simulate the critical area of a welded joint. The elasticity limit for the specimen was determined and stress distribution was achieved in the joint to indicate critical parts of a welded T-joint and predict the critical locations for crack initiation in this kind of joint. Simulation and experimental results show good in agreement and the sources of some differences in these results are discussed.Defence Science Journal, 2010, 60(1), pp.112-118, DOI:http://dx.doi.org/10.14429/dsj.60.11

Modelling Free and Oxide-supported Nanoalloy Catalysts : Comparison of Bulk-immiscible Pd-Ir and Au-Rh system and influence of a TiO2 support

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