4,892 research outputs found

    Algorithms & implementation of advanced video coding standards

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    Advanced video coding standards have become widely deployed coding techniques used in numerous products, such as broadcast, video conference, mobile television and blu-ray disc, etc. New compression techniques are gradually included in video coding standards so that a 50% compression rate reduction is achievable every five years. However, the trend also has brought many problems, such as, dramatically increased computational complexity, co-existing multiple standards and gradually increased development time. To solve the above problems, this thesis intends to investigate efficient algorithms for the latest video coding standard, H.264/AVC. Two aspects of H.264/AVC standard are inspected in this thesis: (1) Speeding up intra4x4 prediction with parallel architecture. (2) Applying an efficient rate control algorithm based on deviation measure to intra frame. Another aim of this thesis is to work on low-complexity algorithms for MPEG-2 to H.264/AVC transcoder. Three main mapping algorithms and a computational complexity reduction algorithm are focused by this thesis: motion vector mapping, block mapping, field-frame mapping and efficient modes ranking algorithms. Finally, a new video coding framework methodology to reduce development time is examined. This thesis explores the implementation of MPEG-4 simple profile with the RVC framework. A key technique of automatically generating variable length decoder table is solved in this thesis. Moreover, another important video coding standard, DV/DVCPRO, is further modeled by RVC framework. Consequently, besides the available MPEG-4 simple profile and China audio/video standard, a new member is therefore added into the RVC framework family. A part of the research work presented in this thesis is targeted algorithms and implementation of video coding standards. In the wide topic, three main problems are investigated. The results show that the methodologies presented in this thesis are efficient and encourage

    The Regulatory Role of MeAIB in Protein Metabolism and the mTOR Signaling Pathway in Porcine Enterocytes.

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    Amino acid transporters play an important role in cell growth and metabolism. MeAIB, a transporter-selective substrate, often represses the adaptive regulation of sodium-coupled neutral amino acid transporter 2 (SNAT2), which may act as a receptor and regulate cellular amino acid contents, therefore modulating cellular downstream signaling. The aim of this study was to investigate the effects of MeAIB to SNAT2 on cell proliferation, protein turnover, and the mammalian target of rapamycin (mTOR) signaling pathway in porcine enterocytes. Intestinal porcine epithelial cells (IPEC)-J2 cells were cultured in a high-glucose Dulbecco's modified Eagle's (DMEM-H) medium with 0 or 5 mmoL/L System A amino acid analogue (MeAIB) for 48 h. Cells were collected for analysis of proliferation, cell cycle, protein synthesis and degradation, intracellular free amino acids, and the expression of key genes involved in the mTOR signaling pathway. The results showed that SNAT2 inhibition by MeAIB depleted intracellular concentrations of not only SNAT2 amino acid substrates but also of indispensable amino acids (methionine and leucine), and suppressed cell proliferation and impaired protein synthesis. MeAIB inhibited mTOR phosphorylation, which might be involved in three translation regulators, EIF4EBP1, IGFBP3, and DDIT4 from PCR array analysis of the 84 genes related to the mTOR signaling pathway. These results suggest that SNAT2 inhibition treated with MeAIB plays an important role in regulating protein synthesis and mTOR signaling, and provide some information to further clarify its roles in the absorption of amino acids and signal transduction in the porcine small intestine

    Document Clustering Based On Max-Correntropy Non-Negative Matrix Factorization

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    Nonnegative matrix factorization (NMF) has been successfully applied to many areas for classification and clustering. Commonly-used NMF algorithms mainly target on minimizing the l2l_2 distance or Kullback-Leibler (KL) divergence, which may not be suitable for nonlinear case. In this paper, we propose a new decomposition method by maximizing the correntropy between the original and the product of two low-rank matrices for document clustering. This method also allows us to learn the new basis vectors of the semantic feature space from the data. To our knowledge, we haven't seen any work has been done by maximizing correntropy in NMF to cluster high dimensional document data. Our experiment results show the supremacy of our proposed method over other variants of NMF algorithm on Reuters21578 and TDT2 databasets.Comment: International Conference of Machine Learning and Cybernetics (ICMLC) 201

    Estimation of cloud condensation nuclei concentration from aerosol optical quantities: influential factors and uncertainties

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    Large-scale measurements of cloud condensation nuclei (CCN) are difficult to obtain on a routine basis, whereas aerosol optical quantities are more readily available. This study investigates the relationship between CCN and aerosol optical quantities for some distinct aerosol types using extensive observational data collected at multiple Atmospheric Radiation Measurement (ARM) Climate Research Facility (CRF) sites around the world. The influences of relative humidity (RH), aerosol hygroscopicity (<i>f</i><sub>RH</sub>) and single scattering albedo (SSA) on the relationship are analyzed. Better relationships are found between aerosol optical depth (AOD) and CCN at the Southern Great Plains (US), Ganges Valley (India) and Black Forest sites (Germany) than those at the Graciosa Island (the Azores) and Niamey (Niger) sites, where sea salt and dust aerosols dominate, respectively. In general, the correlation between AOD and CCN decreases as the wavelength of the AOD measurement increases, suggesting that AOD at a shorter wavelength is a better proxy for CCN. The correlation is significantly improved if aerosol index (AI) is used together with AOD. The highest correlation exists between CCN and aerosol scattering coefficients (&sigma;<sub>sp</sub>) and scattering AI measured in situ. The CCN–AOD (AI) relationship deteriorates with increasing RH. If RH exceeds 75%, the relationship where AOD is used as a proxy for CCN becomes invalid, whereas a tight &sigma;<sub>sp</sub>–CCN relationship exists for dry particles. Aerosol hygroscopicity has a weak impact on the &sigma;<sub>sp</sub>–CCN relationship. Particles with low SSA are generally associated with higher CCN concentrations, suggesting that SSA affects the relationship between CCN concentration and aerosol optical quantities. It may thus be used as a constraint to reduce uncertainties in the relationship. A significant increase in &sigma;<sub>sp</sub> and decrease in CCN with increasing SSA is observed, leading to a significant decrease in their ratio (CCN / &sigma;<sub>sp</sub>) with increasing SSA. Parameterized relationships are developed for estimating CCN, which account for RH, particle size, and SSA

    Płacenie podatków, społeczny wkład w ograniczanie zanieczyszczeń i poczucie satysfakcji

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    Using data from the China part of the World Value Survey (WVS), this paper empirically studies the impact of air pollution on happiness, and further, the citizens’ willingness to pay (WTP) for pollution prevention and its determinants. The result confirms that air pollution significantly worsens happiness. Regarding he WTP, it is differentiated in the form of tax and social contribution. Contrary to the expectation that the air pollution level affects the WTP, the concern on the environment plays a bigger role in increasing the WTP. Besides, the WTP are shown significantly influenced by tax compliance incentives, trust in the government or environmental organizations, attitudes toward environmental protection responsibilities and the family income, which sheds light on effective environmental policy making and implementation.W artykule, wykorzystując dane odnoszące się do Chin w ramach bazy World Value Survey (WVS), omówiono badania empiryczne odnoszące się wpływu zanieczyszczeń powietrza na poczucie satysfakcji obywateli, a także ich gotowości do zapłaty za zanieczyszczenia powietrza i ich determinanty. Otrzymane rezultaty potwierdzają, że zanieczyszczenia powietrza znacząco pogarszają poczucie satysfakcji. Biorąc pod uwagę gotowość do zapłaty, odpowiedź jest uzależniona od formy podatku i społecznego zaangażowania. Przeciwnie do oczekiwań, że zanieczyszczenia powietrza wpływają bezpośrednio gotowość do zapłaty, okazało się, że ważniejsza jest troska o środowisko. Ponadto,&nbsp; na gotowość do zapłaty wpływają sensowne podatki, zaufanie do rządu, organizacji ekologicznych, świadomość odpowiedzialności za środowisko, a także osiągany dochód, co zarazem pozwala ocenić efektywność polityki środowiskowej i jej wdrażania

    Inclusive governance over agricultural biotechnology: risk assessment and public participation

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    A public outcry opposing the use of genetic modification of rice has produced a governance deadlock in China, which threatens to undermine attempts to reap the benefits that modern agricultural biotechnology can offer to the Chinese people. It is argued that this opposition to the agricultural use of modern technology is, in large part, the result, not only of lack of public participation in the decisions involved, but of an over-reliance on conventional approaches to risk assessment that do not adequately take account of the interests of all who stand to be affected by the use of the technology. Public participation is necessary, but it must be guided by equitable principles that take proper account of the rights and interests of all stakeholders. It is argued that a governance strategy based on the Principle of Generic Consistency (PGC) of the American philosopher Alan Gewirth has promise to counter the distrust of the regulators that fuels the deadlock because the PGC can be justified from the perspective of Marxist and Confucian principles that dominate the Chinese political and ethical landscape
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