Adaptive structure concept factorization for multiview clustering

Most existing multiview clustering methods require that graph matrices in different views are computed beforehand and that each graph is obtained independently. However, this requirement ignores the correlation between multiple views. In this letter, we tackle the problem of multiview clustering by jointly optimizing the graph matrix to make full use of the data correlation between views. With the interview correlation, a concept factorization–based multiview clustering method is developed for data integration, and the adaptive method correlates the affinity weights of all views. This method differs from nonnegative matrix factorization–based clustering methods in that it can be applicable to data sets containing negative values. Experiments are conducted to demonstrate the effectiveness of the proposed method in comparison with state-of-the-art approaches in terms of accuracy, normalized mutual information, and purity

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Fluctuation of particles during funnel flow discharge from flat-bottomed silos

Although resonant motion of particles during mass flow discharge from silos has been extensively investigated by earlier researchers, the appearance of such phenomenon during funnel flow discharge has not been emphasized. In this work, the flow behavior of particles during funnel flow discharge from flat-bottomed silos has been investigated by conducting three-dimensional Discrete Element Method (DEM) simulations. It is found that particles in the upper part of flowing zone move collectively, manifested by the oscillatory fluctuations of the velocity and the non-Gaussian characteristics of the fluctuations of individual velocity around the average. Correlation analysis and discrete Fourier transform have been performed to characterize the emission and propagation of velocity fluctuation. It is found that the observed resonant motion of particles is induced by the regular fluctuation of contact force between particles, and there exists an intermediate region in the converging part of the flowing zone. The bottom boundary of this region corresponds to the emission source from which the velocity wave propagates upward and downward. Its upper boundary coincides with that of the converging part of the flowing zone and is featured by the most violent fluctuation of contact force. The simulation results thus suggest that the discharge of granular assembly seems to be determined by the rheological behavior of particles in this intermediate region

Graph-regularized concept factorization for multi-view document clustering

We propose a novel multi-view document clustering method with the graph-regularized concept factorization (MVCF). MVCF makes full use of multi-view features for more comprehensive understanding of the data and learns weights for each view adaptively. It also preserves the local geometrical structure of the manifolds for multi-view clustering. We have derived an efficient optimization algorithm to solve the objective function of MVCF and proven its convergence by utilizing the auxiliary function method. Experiments carried out on three benchmark datasets have demonstrated the effectiveness of MVCF in comparison to several state-of-the-art approaches in terms of accuracy, normalized mutual information and purity

A Docking Mechanism Based on a Stewart Platform and Its Tracking Control Based on Information Fusion Algorithm

Aiming at the problem of unmanned reconfiguration and docking of ground vehicles under complex working conditions, we designed a piece of docking equipment composed of an active mechanism based on a six-degree-of-freedom platform and a locking mechanism with multi-sensors. Through the proposed control method based on laser and image sensor information fusion calculation, the six-dimensional posture information of the mechanism during the docking process is captured in real time so as to achieve high-precision docking. Finally, the effectiveness of the method and the feasibility of the 6-DOF platform are verified by the established model. The results show that the mechanism can meet the requirements of smooth docking of ground unmanned vehicles

CFD modeling the hydrodynamics of binary particle mixture in pseudo-2D bubbling fluidized bed: Effect of model parameters

The hydrodynamics of binary coal-sand mixture in a pseudo-2D rectangular bubbling fluidized bed (0.385 m x 0.005 m x 0.128 m) was simulated using the multi-fluid Eulerian model incorporating the kinetic theory of granular flow. Parametric studies of the boundary wall condition, particle-particle restitution coefficient, friction packing limit, as well as transport equation for granular temperature were performed to investigate their influences on the predicted mixing/segregation behavior. The CFD simulation results demonstrated that the predicted mixing behavior was closely related to the expression for granular temperature transport equation and specularity coefficient. When the full transport equation for granular temperature was adopted, the predicted mixing degree decreased with the increase of specularity coefficient. And the best agreement between simulation results and experimental data was achieved when specularity coefficient was equal to 1.0. Nevertheless, when the algebraic transport equation for granular temperature was adopted, the system was always predicted in well-mixing rather than segregation state. Under the full transport equation for granular temperature and the no slip boundary wall condition, the predicted mixing degree decreased with the increase of the particle-particle restitution coefficient and frictional packing limit. The supplementary simulations indicated that for the considered gas-solid system there exist a critical bed thickness larger than which the system was in well-mixing state and the simulation results were independent from the investigated parameters. The hydrodynamic analysis indicated that the reduction of bubble size and the solid axial movement could be the mechanism responsible for the occurrence of axial segregation. (C) 2016 Elsevier B.V. All rights reserved.</p

CFD model of coal pyrolysis in fixed bed reactor

A three dimensional transient model was developed to simulate the pyrolysis process of coal in fixed bed reactor. The model considered a number of aspects associated with coal pyrolysis such as the evaporation and condensation of physical water, the release of volatiles, secondary cracking of pyrolysis tar and the variation of porosity. Conductive, radiative and convective types of heat transfer were all taken into account in the model. The phase transformation of physical water was modeled using the Lee model (Lee, 1980) available in the commercial CFD software Fluent. The multiple independent parallel reaction (MIPR) model was applied to predict the generations of volatile products. The secondary cracking of tar was described using the model proposed by Wurzenberger et al. (2002). The model was implemented in Fluent and validated through modeling the pyrolysis process of low-rank sub-bituminous coal in four laboratory-scale and externally heated fixed-bed reactors with or without internals. The predicted temperature evolutions of coal charge were in all quantitative agreements with experimental results. And the influences of internals on the yield of tar were also successfully captured by the simulations. (C) 2019 Elsevier Ltd. All rights reserved