587 research outputs found

    Source-side context-informed hypothesis alignment for combining outputs from machine translation systems

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    This paper presents a new hypothesis alignment method for combining outputs of multiple machine translation (MT) systems. Traditional hypothesis alignment algorithms such as TER, HMM and IHMM do not directly utilise the context information of the source side but rather address the alignment issues via the output data itself. In this paper, a source-side context-informed (SSCI) hypothesis alignment method is proposed to carry out the word alignment and word reordering issues. First of all, the source–target word alignment links are produced as the hidden variables by exporting source phrase spans during the translation decoding process. Secondly, a mapping strategy and normalisation model are employed to acquire the 1- to-1 alignment links and build the confusion network (CN). The source-side context-based method outperforms the state-of-the-art TERbased alignment model in our experiments on the WMT09 English-to-French and NIST Chinese-to-English data sets respectively. Experimental results demonstrate that our proposed approach scores consistently among the best results across different data and language pair conditions

    Low-resource machine translation using MATREX: The DCU machine translation system for IWSLT 2009

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    In this paper, we give a description of the Machine Translation (MT) system developed at DCU that was used for our fourth participation in the evaluation campaign of the International Workshop on Spoken Language Translation (IWSLT 2009). Two techniques are deployed in our system in order to improve the translation quality in a low-resource scenario. The first technique is to use multiple segmentations in MT training and to utilise word lattices in decoding stage. The second technique is used to select the optimal training data that can be used to build MT systems. In this year’s participation, we use three different prototype SMT systems, and the output from each system are combined using standard system combination method. Our system is the top system for Chinese–English CHALLENGE task in terms of BLEU score

    Exploiting alignment techniques in MATREX: the DCU machine translation system for IWSLT 2008

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    In this paper, we give a description of the machine translation (MT) system developed at DCU that was used for our third participation in the evaluation campaign of the International Workshop on Spoken Language Translation (IWSLT 2008). In this participation, we focus on various techniques for word and phrase alignment to improve system quality. Specifically, we try out our word packing and syntax-enhanced word alignment techniques for the Chinese–English task and for the English–Chinese task for the first time. For all translation tasks except Arabic–English, we exploit linguistically motivated bilingual phrase pairs extracted from parallel treebanks. We smooth our translation tables with out-of-domain word translations for the Arabic–English and Chinese–English tasks in order to solve the problem of the high number of out of vocabulary items. We also carried out experiments combining both in-domain and out-of-domain data to improve system performance and, finally, we deploy a majority voting procedure combining a language model based method and a translation-based method for case and punctuation restoration. We participated in all the translation tasks and translated both the single-best ASR hypotheses and the correct recognition results. The translation results confirm that our new word and phrase alignment techniques are often helpful in improving translation quality, and the data combination method we proposed can significantly improve system performance

    Calibrating Path Choices and Train Capacities for Urban Rail Transit Simulation Models Using Smart Card and Train Movement Data

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    Transit network simulation models are often used for performance and retrospective analysis of urban rail systems, taking advantage of the availability of extensive automated fare collection (AFC) and automated vehicle location (AVL) data. Important inputs to such models, in addition to origin-destination flows, include passenger path choices and train capacity. Train capacity, which has often been overlooked in the literature, is an important input that exhibits a lot of variabilities. The paper proposes a simulation-based optimization (SBO) framework to simultaneously calibrate path choices and train capacity for urban rail systems using AFC and AVL data. The calibration is formulated as an optimization problem with a black-box objective function. Seven algorithms from four branches of SBO solving methods are evaluated. The algorithms are evaluated using an experimental design that includes five scenarios, representing different degrees of path choice randomness and crowding sensitivity. Data from the Hong Kong Mass Transit Railway (MTR) system is used as a case study. The data is used to generate synthetic observations used as "ground truth". The results show that the response surface methods (particularly Constrained Optimization using Response Surfaces) have consistently good performance under all scenarios. The proposed approach drives large-scale simulation applications for monitoring and planning

    Optimization of isolation and purification of total flavonoids from Ardisia mamillata Hance roots using macroporous resins, and determination of their antioxidant activity

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    Purpose: To isolate, purify and determine the antioxidant property of total flavonoids from the roots of Ardisia mamillata, so as to provide a  theoretical basis for development of natural antioxidants.Methods: Macroporous resin was used to optimize the isolation and  purification of total flavonoids, taking adsorption rate and resolution rate as evaluation indices. The antioxidant property of the purified total flavonoids was determined using 1,1-diphenyl-2-picrylhydrazyl radical 2,2-diphenyl-1-(2,4,6- trinitrophenyl)hydrazyl (DPPH) radical scavenging activity.Results: The best conditions for separation and purification of total  flavonoids from Ardisia mamillata roots were: use of ADS-7 resin, loading total flavonoid concentration of 0.8896 mg/mL, loading buffer flow rate of 1.5 mL/min, loading buffer pH of 4.48, elution ethanol concentration of 60 %, and flow rate of 2.5 mL/min. Under these conditions, the degree of purification of total flavonoids of Ardisia mamillata root was 76.43 ± 0.36 %, adsorption rate was 96.52 ± 0.19 %, while resolution rate was 99.31 ± 0.27 %. When the concentration of the purified total flavonoids was 4.0 mg/mL, its DPPH radical scavenging activity was stronger than that of the standard, butylated hydroxytoluene (BHT), but lower than that of vitamin C.Conclusion: ADS-7 resin is the best macroporous resin for the purification of total flavonoids from the radix of Ardisia mamillata Hance, under the  optimized conditions. The purified total flavonoids of Ardisia mamillata root have stronger DPPH radical scavenging ability than the standard, BHT.Keywords: Szechwan raspberry root, Flavonoids, Macroporous adsorption resin, ADS-7 resin, Purification, Antioxidan

    Loureirin B attenuates amiodarone-induced pulmonary fibrosis by suppression of TGFβ1/Smad2/3 pathway

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    Purpose: To investigate the therapeutic effect of loureirin B (LB) on amiodarone (AD)-induced pulmonary fibrosis (PF).Methods: Forty-eight male C57BL/6 mice, 8–10 weeks of age, were divided into four groups (n=12). Oral administration of amiodarone hydrochloride (AD) was performed for 4 weeks to induce pulmonary fibrosis. The degree of fibrosis was assessed by Masson staining, while collagen I and α-smooth muscle actin (α-SMA) levels were evaluated by Western blot analysis. ELISA was used to measure the levels of cytokines TNF-α, IL-1β, and IL-6 in bronchoalveolar lavage fluid (BALF) and lung tissue. Levels of p- Smad2, Smad2, p-Smad3 and Smad3 were determined by western blotting.Results: AD treatment increased the collagen levels and expression levels of collagen I and α-smooth muscle actin (α-SMA) in lung tissue and of inflammatory cytokines TNF-α, IL-1β, and IL-6, in both bronchoalveolar lavage fluid (BALF) and lung tissue in a dose-dependent manner (p < 0.01).Furthermore, AD increased the levels of p-Smad2/3. AD-induced increases in collagen I and α-SMA levels were reversed by loureirin B (LB). In addition, LB reduced AD-induced increased levels of the inflammatory cytokines TNF-α, IL-1β, and IL-6 in both bronchoalveolar lavage fluid (BALF) and lung tissue (p < 0.01).Conclusion: These results demonstrate that LB downregulates expression of fibrosis-related proteins and suppresses AD-induced PF. The  mechanism responsible for the protective effect of LB on ADinduced PF might involve inhibition of the Smad2/3 pathway. Thus, LB is a potential therapeutic agent for the management of PF. Keywords: Amiodarone, Loureirin B, Pulmonary fibrosis, Smad, Inflammatio

    The meninges is a source of retinoic acid for the late-developing hindbrain

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    One general function for retinoic acid (RA) is pattern organization in the CNS. This regulatory factor has an essential role in spinal cord motor neuron and early posterior hindbrain development. In the anterior CNS, however, there is only a limited number of foci of RA synthesis, and less attention has been placed on regions such as the anterior hindbrain where RA synthesizing enzymes are absent. This study shows that a rich source of RA lies around the hindbrain from the RA synthetic enzyme retinaldehyde dehydrogenase-2 (RALDH2) present in the surrounding meninges and mesenchyme by embryonic day 13. RALDH2 is not distributed uniformly throughout the meninges but is restricted to territories over the developing hindbrain, suggesting that RA signaling may be localized to those regions. Further regulation of RA signaling is provided by the presence of a RA sink in the form of the CYP26B1 RA catabolic enzyme expressed in deeper regions of the brain. As a guide to the neural anatomy of hindbrain RA signaling, we used a mouse transgenic for a lacZ reporter gene driven by a RA response element (RAREhsplacZ) to identify regions of RA signaling. This reporter mouse provides evidence that RA signaling in the hindbrain after embryonic day 13 occurs in the regions of the cerebellum and precerebellar system adjacent to sources of RA, including the inferior olive and the pontine nuclei
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