50,531 research outputs found
Comparative analysis of component design problems for integrated hydraulic transformers
No full textEnergy-saving research of hydraulic system has become a central issue recently. This paper has made a comprehensive review of the hydraulic transformer (HT) which is the key component in common pressure rail (CPR) hydraulic energy-saving system. First, the invention process and basic working principle of the HT are introduced. Then, HTs are divided into three categories to discuss the current development in accordance with the different structures for realizing the control angle regulation. In addition, the problems existing in the research of HTs are summarized and a new variable displacement HT is proposed for the first time. Finally, the future development of the HT is discussed
Sexual dimorphism, dispersal patterns, and breeding biology of the Taiwan Yuhina: a joint-nesting passerine
No full textA 2 h periodic variation in the low-mass X-ray binary Ser X-1
No full textSpectroscopy of the low-mass X-ray binary Ser X-1 using the Gran Telescopio Canarias have revealed a ?2 h periodic variability that is present in the three strongest emission lines. We tentatively interpret this variability as due to orbital motion, making it the first indication of the orbital period of Ser X-1. Together with the fact that the emission lines are remarkably narrow, but still resolved, we show that a main-sequence K dwarf together with a canonical 1.4 M? neutron star gives a good description of the system. In this scenario, the most likely place for the emission lines to arise is the accretion disc, instead of a localized region in the binary (such as the irradiated surface or the stream-impact point), and their narrowness is due instead to the low inclination (?10°) of Ser X-1
Truth finding by reliability estimation on inconsistent entities for heterogeneous data sets
No full textAn important task in big data integration is to derive accurate data records from noisy and conflicting values collected from multiple sources. Most existing truth finding methods assume that the reliability is consistent on the whole data set, ignoring the fact that different attributes, objects and object groups may have different reliabilities even wrt the same source. These reliability differences are caused by the hardness differences in obtaining attribute values, non-uniform updates to objects and the differences in group privileges. This paper addresses the problem how to compute truths by effectively estimating the reliabilities of attributes, objects and object groups in a multi-source heterogeneous data environment. We first propose an optimization framework TFAR, its implementation and Lagrangian duality solution for Truth Finding by Attribute Reliability estimation. We then present a Bayesian probabilistic graphical model TFOR and an inference algorithm applying Collapsed Gibbs Sampling for Truth Finding by Object Reliability estimation. Finally we give an optimization framework TFGR and its implementation for Truth Finding by Group Reliability estimation. All these models lead to a more accurate estimation of the respective attribute, object and object group reliabilities, which in turn can achieve a better accuracy in inferring the truths. Experimental results on both real data and synthetic data show that our methods have better performance than the state-of-art truth discovery methods.Hui Tian, Wenwen Sheng, Hong Shen, Can Wan
H-infinity filtering with randomly occurring sensor saturations and missing measurements
No full textThis is the post-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2012 ElsevierIn this paper, the H∞ filtering problem is investigated for a class of nonlinear systems with randomly occurring incomplete information. The considered incomplete information includes both the sensor saturations and the missing measurements. A new phenomenon of sensor saturation, namely, randomly occurring sensor saturation (ROSS), is put forward in order to better reflect the reality in a networked environment such as sensor networks. A novel sensor model is then established to account for both the ROSS and missing measurement in a unified representation by using two sets of Bernoulli distributed white sequences with known conditional probabilities. Based on this sensor model, a regional H∞ filter with a certain ellipsoid constraint is designed such that the filtering error dynamics is locally mean-square asymptotically stable and the H∞-norm requirement is satisfied. Note that the regional l2 gain filtering feature is specifically developed for the random saturation nonlinearity. The characterization of the desired filter gains is derived in terms of the solution to a convex optimization problem that can be easily solved by using the semi-definite program method. Finally, a simulation example is employed to show the effectiveness of the filtering scheme proposed in this paper.This work was supported in part by the Engineering and Physical Sciences Research Council (EPSRC) of the UK under Grant GR/S27658/01, the Royal Society of the UK, the National Natural Science Foundation of China under Grants 61028008 and 60974030, the National 973 Program of China under Grant 2009CB320600, and the Alexander von Humboldt Foundation of Germany
Mathematical study of a model for liquid-vapour phase change in porous media
No full textMathematical study of a model for liquid-vapour phase change in porous media / by K.-H. Hoffmann, W. Shen & S. Zheng. - Augsburg, 1991. - 21 S. - (Schwerpunktprogramm der DFG Anwendungsbezogene Optimierung und Steuerung ; 312
Observer reliability in assessing placental maturity by histology
No full textT Y Khong, A Staples, R W Bendon, H M Chambers, S J Gould, S Knowles, S Shen-Schwar
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