86 research outputs found

    Event-triggered Synchronization of Multi-agent Systems with Partial Input Saturation

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    This paper is concerned with the distributed event/self-triggered synchronization problem for general linear multi-agent systems with partial input saturation. Both the event-based and self-triggered laws are designed using the local sampled, possibly saturated, state, which ensures the bounded synchronization of the multi-agent systems, and exclusion of the Zeno-behavior. The continuous communication between agents is avoided under these triggering protocols. Different from the existing related works, we show the fully distributed design for multi-agent systems, where the synchronization criteria, the designed input laws, and the proposed triggering protocols do not depend on any global information of the communication topology. In addition, the computation load of multi-agent systems is reduced significantly

    DAGKT: Difficulty and Attempts Boosted Graph-based Knowledge Tracing

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    In the field of intelligent education, knowledge tracing (KT) has attracted increasing attention, which estimates and traces students' mastery of knowledge concepts to provide high-quality education. In KT, there are natural graph structures among questions and knowledge concepts so some studies explored the application of graph neural networks (GNNs) to improve the performance of the KT models which have not used graph structure. However, most of them ignored both the questions' difficulties and students' attempts at questions. Actually, questions with the same knowledge concepts have different difficulties, and students' different attempts also represent different knowledge mastery. In this paper, we propose a difficulty and attempts boosted graph-based KT (DAGKT), using rich information from students' records. Moreover, a novel method is designed to establish the question similarity relationship inspired by the F1 score. Extensive experiments on three real-world datasets demonstrate the effectiveness of the proposed DAGKT.Comment: 12 pages, 3figures, conference:ICONI

    Numerical assessment of the reduction of specific absorption rate by adding high dielectric materials for fetus MRI at 3 T

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    The specific absorption rate (SAR) is an important issue to be considered in fetus MRI at 3 T due to the high radiofrequency energy deposited inside the body of pregnant woman. The high dielectric material (HDM) has shown its potential for enhancing B field and reducing SAR in MRI. The aim of this study is to assess the feasibility of SAR reduction by adding an HDM to the fetus MRI. The feasibility of SAR reduction is numerically assessed in this study, using a birdcage coil in transmission loaded with an electromagnetic pregnant woman model in the SEMCAD-EM solver. The HDMs with different geometric arrangements and dielectric constants are manually optimized. The B1+ B−1+{B-1}^ + homogeneity is also considered while calculating the optimized fetus 10 g local SAR among different strategies in the application of HDM. The optimum maximum fetus 10 g local SAR was obtained as 2.25 W/kg, by using two conformal pads placed left and right with the dielectric constant to be 400, reduced by 24.75% compared to that without the HDM. It indicated that the SAR can be significantly reduced with strategic placement of the HDM and the use of HDM may provide a simple, effective and low-cost method for reducing the SAR for the fetus MRI at 3 T

    Design of Hypervelocity-Impact Damage Evaluation Technique Based on Bayesian Classifier of Transient Temperature Attributes

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    With the rapid increasement of space debris on earth orbit, the hypervelocity-impact (HVI) of space debris can cause some serious damages to the spacecraft, which can affect the operation security and reliability of spacecraft. Therefore, the damage detection of the spacecrafts has become an urgent problem to be solved. In this paper, a method is proposed to detect the damage of spacecraft. Firstly, a variable-interval method is proposed to extract the effective information from the infrared image sequence. Secondly, in order to mine the physical meaning of the thermal image sequence, five attributes are used to construct a feature space. After that, a Naive Bayesian classifier is established to mine the information of different damaged areas. Then, a maximum interclass distance function is used choose the representative of each class. Finally, in order to visualize damaged areas, the Canny operator is used to extract the edge of the damage. In the experiment, ground tests are used to simulate hypervelocity impacts in space. Historical data of natural damaged material and artificial damaged material are used to build different classifiers. After that, the effective of classifiers is illustrated by accuracy, F-score and AUC. Then, two different types of materials are detected by proposed method, Independent Component Analysis (ICA) and Fuzzy C-means (FCM). The results show that the proposed method is more accurate than other methods

    Two novel TSC2 mutations in renal epithelioid angiomyolipoma sensitive to everolimus.

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    People who suffers renal angiomyolipoma (AML) has a low quality of life. It is widely known that genetic factors including TSC2 mutation contribute to certain populations of renal AML-bearing patients. In this study, we are the first to identify novel TSC2 mutations in one Chinese renal epithelioid AML patient: c.2652C>A; c.2688G>A based on sequencing result from biopsy tissue. These two somatic mutations cause a translational stop of TSC2, which leads to mTORC1 activation. Given the fact that activation of mTORC1 ensures cell growth and survival, we applied its inhibitor, FDA-approved everolimus, to this woman. After months of treatment with everolimus, Computer-Tomography (CT) scan results showed that everolimus successfully reduced tumor growth and distal metastasis and achieved partial response (PR) to everolimu according to Response Evaluation Criteria in Solid Tumors (RECIST version 1.1). Further Blood Routine Examination results showed the concentration of red cell mass, hemoglobin, white blood cell (WBC), platelets and hematocrit (HCT) significantly returned to normal levels indicating patients with these two TSC2 mutations could be effectively treated by everolimus

    Finishing the euchromatic sequence of the human genome

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    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

    Enhanced Adsorption of Mercury(II) and Cadmium(II) from Aqueous Solution onto Rice Bran Modified with Chelating Ligands

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    To enhance the removal of mercury (Hg(II)) and cadmium (Cd(II)) from aqueous solutions, rice bran (RB) was reacted with epichlorohydrin and then modified with ethylenediamine and sodium chloroacetate to bear iminodiacetate functional groups. The modified rice bran (MRB) was characterized by Fourier transform-infrared spectroscopy (FT-IR), thermogravimetric analysis (TG), energy dispersive spectroscopy (EDS), back titration, and X-ray photoelectron spectroscopy (XPS). The adsorption properties of MRB for Hg(II)/Cd(II) ions were also evaluated in batch experiments. The sorption kinetic experimental data were best described by the pseudo-second-order model. The maximum adsorption capacity (163.9 mg/g for Hg(II) at pH 5.0 and 106.4 mg/g for Cd(II) at pH 6.0) was observed at 298 K, and the isotherm adsorption equilibrium of MRB was followed by Langmuir isotherm equation. The major adsorption mechanisms should be predominantly controlled by the formation of complexes between the functional groups of MRB and Hg(II)/Cd(II) ions as well as ion-exchange. The regeneration experiments showed that the MRB could be successfully reused for six cycles when 0.1 M HCl eluent was used

    Complete chloroplast genome sequence of ‘Field Muskmelon,’ an invasive weed to China

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    Cucumis melo L. var. agrestis Naud., commonly known as ‘Field Muskmelon,’ is an annual invasive weed in many parts of China. However, there is very little available information about the chloroplast genome of this species. Here, we first report and characterize its complete chloroplast genome sequence based on Illumina paired-end sequencing data. The complete plastid genome was 155,402 bp, which contained inverted repeats (IR) of 25,514 bp separated by a large single-copy (LSC) and a small single copy (SSC) of 86,287 bp and 18,087 bp, respectively. The complete chloroplast genome contains 133 genes, comprising 87 protein-coding genes, 37 tRNA genes, 8 rRNA genes and 1 pseudogene. The overall GC content of the plastome is 36.9%. The phylogenetic analysis of 16 selected chloroplast genomes demonstrated that C. melo var. agrestis Naud was close to congeneric species C. xhytivus

    Visualizing Hotspots and Future Trends in Phytomining Research Through Scientometrics

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    Phytomining has attracted widespread attention as a technique for harvesting “bio-ore.” This technology has potential applications in the metal and minerals industry for low-grade metal and mineral mining as well as metal recycling from polluted soil. The hotspots and future trends of this technology deserve in-depth exploration. This paper presents a systematic review of the phytomining research area through the scientometrics method based on the citation data collected from the Web of Science Core Collection (WoSCC). The results show that the earliest phytomining-related research was published in 1997. Between 1997 and 2019, 232 publications were published in 109 journals. Plant and Soil, the International Journal of Phytoremediation, and the Journal of Geochemical Exploration were the top three most prolific journals and accounted for 18.1% of these publications. Guillaume Echevarria, J.L. Morel, and Antony Van der Ent were the top three most prolific authors, and their work accounted for 40.1% of these publications. The cluster results of document co-citation analysis revealed that the hotspots in phytomining research area mainly includes “nickel accumulation,” “heavy metal uptake,” “mining site,” “heavy metal,” “hyperaccumulation yield,” “growth effect,” and “alternative method.” Keyword burst detection results find that the hot topics have changed over time from “phytomining” to “agromining”; from “contaminated soil” to “serpentine soil”; and from “mechanism” to “phytomining process” and “commercial phytoextraction.” This study describes the intellectual landscape of research and provides future research directions for phytomining research so that researchers can identify future research topics and partners
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