3,424 research outputs found
Ionic effect on combing of single DNA molecules and observation of their force-induced melting by fluorescence microscopy
Molecular combing is a powerful and simple method for aligning DNA molecules
onto a surface. Using this technique combined with fluorescence microscopy, we
observed that the length of lambda-DNA molecules was extended to about 1.6
times their contour length (unextended length, 16.2 micrometers) by the combing
method on hydrophobic polymethylmetacrylate (PMMA) coated surfaces. The effects
of sodium and magnesium ions and pH of the DNA solution were investigated.
Interestingly, we observed force-induced melting of single DNA molecules.Comment: 12 page
A Three-Dimensional Cooperative Guidance Law of Multimissile System
In order to conduct saturation attacks on a static target, the cooperative guidance problem of multimissile system is researched. A three-dimensional guidance model is built using vector calculation and the classic proportional navigation guidance (PNG) law is extended to three dimensions. Based on this guidance law, a distributed cooperative guidance strategy is proposed and a consensus protocol is designed to coordinate the time-to-go commands of all missiles. Then an expert system, which contains two extreme learning machines (ELM), is developed to regulate the local proportional coefficient of each missile according to the command. All missiles can arrive at the target simultaneously under the assumption that the multimissile network is connected. A simulation scenario is given to demonstrate the validity of the proposed method
1-Isopropyl-4-tosylÂpiperazin-1-ium trifluoroÂacetate
In the title compound, C14H23N2O2S+·C2F3O2
−, the piperazine ring adopts a chair conformation. The crystal packing is stabilized by C—H⋯O and N—H⋯O hydrogen bonds between the cation and anion. The F atoms are disordered over two positions; the site occupancy factors are 0.55 (2) and 0.45 (2)
Knowledge Restore and Transfer for Multi-label Class-Incremental Learning
Current class-incremental learning research mainly focuses on single-label
classification tasks while multi-label class-incremental learning (MLCIL) with
more practical application scenarios is rarely studied. Although there have
been many anti-forgetting methods to solve the problem of catastrophic
forgetting in class-incremental learning, these methods have difficulty in
solving the MLCIL problem due to label absence and information dilution. In
this paper, we propose a knowledge restore and transfer (KRT) framework for
MLCIL, which includes a dynamic pseudo-label (DPL) module to restore the old
class knowledge and an incremental cross-attention(ICA) module to save
session-specific knowledge and transfer old class knowledge to the new model
sufficiently. Besides, we propose a token loss to jointly optimize the
incremental cross-attention module. Experimental results on MS-COCO and PASCAL
VOC datasets demonstrate the effectiveness of our method for improving
recognition performance and mitigating forgetting on multi-label
class-incremental learning tasks
Evolution of worldwide stock markets, correlation structure and correlation based graphs
We investigate the daily correlation present among market indices of stock
exchanges located all over the world in the time period Jan 1996 - Jul 2009. We
discover that the correlation among market indices presents both a fast and a
slow dynamics. The slow dynamics reflects the development and consolidation of
globalization. The fast dynamics is associated with critical events that
originate in a specific country or region of the world and rapidly affect the
global system. We provide evidence that the short term timescale of correlation
among market indices is less than 3 trading months (about 60 trading days). The
average values of the non diagonal elements of the correlation matrix,
correlation based graphs and the spectral properties of the largest eigenvalues
and eigenvectors of the correlation matrix are carrying information about the
fast and slow dynamics of correlation of market indices. We introduce a measure
of mutual information based on link co-occurrence in networks, in order to
detect the fast dynamics of successive changes of correlation based graphs in a
quantitative way.Comment: 8 pages, 11 figure
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