456 research outputs found

    High compression ratio image processing techniques using combinations of WT and IFS

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    Many works of compressing image based on wavelet transformation have been presented in recent years. Also, the method of fractals is used in this field. The first method uses the pyramid subband decomposition, and the second takes advantage of the self-similarity between the basic image and subimages. We combine these two methods as a hybrid algorithm to complete the image compression. The experiments show that this method has a better performance than many others, especially, in a high compression ratio situation. A comparison with the famous embedded zero tree wavelet (EZW) algorithm shows that its performance is close to the EZW algorithm.published_or_final_versio

    Academic research in emerging knowledge-based economies : the case of Sri Lankan construction industry

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    Purpose Knowledge-based economies are popular in the present world. Simultaneously, universities are becoming more responsible for leading economic development through research. As a key contributor to the national economy, it is vital for the construction industry to move beyond outdated practices, and hence, reviewing the role of academic research in empowering construction industry with knowledge is essential. This paper focuses on how relevant theories conceptualise the expected role of academic research in the innovative development of an industry and the specific location in Sri Lankan construction industry. Design/methodology/approach Following a comprehensive literature review, empirical data were collected from Sri Lankan context with a mixed approach informed by a pragmatist philosophical stance. The perspective of academia and industry practitioners were deductively obtained through surveys and inductively explored through qualitative interviews. Findings This study provides evidence that academic research in Sri Lanka does not contribute effectively to innovative construction management. Due to the absence of industry-focused knowledge dissemination strategies, the academic-industry relationships are mostly non-research based. The industry lacks in research informed-decision making, leading to lesser innovations. Research limitations/implications The research conclusions are more applicable to the developing-country construction industry contexts. Practical implications The research urges the need for improved academic-industry research collaborations and strategic knowledge dissemination movements. Originality/value The research confirms academic research as a major integral part of developing construction industry in a knowledge-based economy. In establishing the expected role of academic research, the research revealed the current practice to be under-located. Hence, the research prescribes the necessary actions; research collaborations in major and subsequent requirements. Keywords – Academic research, Construction management, Innovation theories, Knowledge-based economies, Knowledge dissemination, Knowledge utilisation, Research collaboration

    Growth mode and strain evolution during InN growth on GaN(0001) by molecular-beam epitaxy

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    The plasma-assisted molecular-beam epitaxy technique was used to study the epitaxial growth of InN on GaN. A relationship between film growth mode and the deposition condition was established by combining reflection high-energy electron diffraction (RHEED) and scanning tunneling microscopy (STM). The sustained RHEED intensity oscillations were recorded for 2D growth while 2D nucleation islands were revealed by STM. Results showed less than three oscillation periods for 3 D growth, indicating the Strnski-Krastanov (SK) growth mode of the film.published_or_final_versio

    InN Island shape and its dependence on growth condition of molecular-beam epitaxy

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    The three-dimensional (3D) island shapes of the InN and its dependence on growth conditions of molecular-beam epitaxy (MBE) were analyzed. The islands were dislocated and the strain in an island depended on its size. The pillar-shaped islands with low aspect ratios represented the equilibrium shape, and the pyrimidal islands with higher aspect ratios were limited by kinetics during MBE growth. The decreasing trend of island aspect ratio with respect to island size was attributed to gradual relaxation of residual strain in dislocated islands.published_or_final_versio

    Scaling of three-dimensional InN islands grown on GaN(0001) by molecular-beam epitaxy

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    The scaling property of three-dimensional InN islands nucleated on GaN(0001) surface during molecular-beam epitaxy (MBE) is investigated. Due to the large lattice mismatch between InN and GaN (∼10%), the islands formed from the Stranski-Krastanow growth mode are dislocated. Despite the variations in (residual) strain and the shape, both the island size and pair separation distributions show the scaling behavior. Further, the size distribution resembles that for submonolayer homoepitaxy with the critical island size i = 1, suggesting that detachment of atoms is not significant. The above results also indicate strain is insignificant in determining the nucleation and growth of dislocated islands during heteroepitaxy by MBE.published_or_final_versio

    Nontrivial phase coupling in polariton multiplets

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    We investigate the phase coupling between spatially separated polariton condensates under nonresonant optical pulsed excitation. In the simple case of two condensates, we observe phase locking either in symmetric or antisymmetric states. We demonstrate that the coupling symmetry depends both on the separation distance and outflow velocity from the condensates. We interpret the observations through stimulated relaxation of polaritons to the phase configuration with the highest occupation. We derive an analytic criterion for the phase locking of a pair-polariton condensate and extend it to polariton multiplets. In the case of three condensates, we predict theoretically and observe experimentally either in-phase locking or the appearance of phase winding with phase differences of �2π/3 between neighbors. The latter state corresponds to a vortex of winding number �1 across the three polariton condensates..P. G. L. and A. V. K. acknowledge EPSRC through Programme Grant on Hybrid Polaritonics EP/M025330/1 and EP/F026455/1 for co-supporting this work. N. G. B acknowledges financial support by the Ministry of Education and Science of the Russian Federation 1425320 (Project DOI: RFMEFI58114X0006). Y. G. R. acknowledges financial support by CONACYT (Mexico) under Grant No. 251808

    Integrating evolution into ecological modelling: accommodating phenotypic changes in agent based models.

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    PMCID: PMC3733718This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Evolutionary change is a characteristic of living organisms and forms one of the ways in which species adapt to changed conditions. However, most ecological models do not incorporate this ubiquitous phenomenon. We have developed a model that takes a 'phenotypic gambit' approach and focuses on changes in the frequency of phenotypes (which differ in timing of breeding and fecundity) within a population, using, as an example, seasonal breeding. Fitness per phenotype calculated as the individual's contribution to population growth on an annual basis coincide with the population dynamics per phenotype. Simplified model variants were explored to examine whether the complexity included in the model is justified. Outputs from the spatially implicit model underestimated the number of individuals across all phenotypes. When no phenotype transitions are included (i.e. offspring always inherit their parent's phenotype) numbers of all individuals are always underestimated. We conclude that by using a phenotypic gambit approach evolutionary dynamics can be incorporated into individual based models, and that all that is required is an understanding of the probability of offspring inheriting the parental phenotype

    Towards Protein Crystallization as a Process Step in Downstream Processing of Therapeutic Antibodies: Screening and Optimization at Microbatch Scale

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    Crystallization conditions of an intact monoclonal IgG4 (immunoglobulin G, subclass 4) antibody were established in vapor diffusion mode by sparse matrix screening and subsequent optimization. The procedure was transferred to microbatch conditions and a phase diagram was built showing surprisingly low solubility of the antibody at equilibrium. With up-scaling to process scale in mind, purification efficiency of the crystallization step was investigated. Added model protein contaminants were excluded from the crystals to more than 95%. No measurable loss of Fc-binding activity was observed in the crystallized and redissolved antibody. Conditions could be adapted to crystallize the antibody directly from concentrated and diafiltrated cell culture supernatant, showing purification efficiency similar to that of Protein A chromatography. We conclude that crystallization has the potential to be included in downstream processing as a low-cost purification or formulation step

    Effective-Range Expansion of the Neutron-Deuteron Scattering Studied by a Quark-Model Nonlocal Gaussian Potential

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    The S-wave effective range parameters of the neutron-deuteron (nd) scattering are derived in the Faddeev formalism, using a nonlocal Gaussian potential based on the quark-model baryon-baryon interaction fss2. The spin-doublet low-energy eigenphase shift is sufficiently attractive to reproduce predictions by the AV18 plus Urbana three-nucleon force, yielding the observed value of the doublet scattering length and the correct differential cross sections below the deuteron breakup threshold. This conclusion is consistent with the previous result for the triton binding energy, which is nearly reproduced by fss2 without reinforcing it with the three-nucleon force.Comment: 21 pages, 6 figures and 6 tables, submitted to Prog. Theor. Phy
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