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2005年08月05日

【期刊论文】Identifying splicing sites in eukaryotic RNA: support vector machine approach

李衍达, Ying-Fei Sun*, Xiao-Dan Fan, Yan-Da Li

Computers in Biology and Medicine 33(2003)17-29,-0001,():

-1年11月30日

摘要

We introduce a new method for splicing sites prediction based on the theory of support vector machines (SVM). The SVM represents a new approach to supervised pattern classification and has been successfully applied to a wide range of pattern recognition problems. In the process of splicing sites prediction, the statistical information of RNA secondary structure in the vicinity of splice sites, e.g. donor and acceptor sites, is introduced in order to compare recognition ratio of true positive and true negative. From the results of comparison, addition of structural information has brought no significant benefit for the recognition of splice sites and had even lowered the rate of recognition. Our results suggest that, through three cross validation, the SVM method can achieve a good performance for splice sites identi7cation.

Support vector machines (, SVM), , Neural network, Sensitivity, Speci7city, Splice site, RNA secondary structure

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2005年08月05日

【期刊论文】Directed Variation in Evolution Strategies

李衍达, Qing Zhou, and Yanda Li, Senior Member, IEEE

IEEE TRANSACTIONS ON EVOLUTIONARY COMPUTATION, VOL. 7, NO.4, AUGUST 2003,-0001,():

-1年11月30日

摘要

Biological evolution gives rise to self-organizing phenomena. Inspired by this theory, directed variation is added to the (μ,λ) evolution strategies (ES) algorithm and it is called directed variation ES (DVES). In DVES, some neighboring individuals in the population mutate correlatively according to the distribution of the whole population. Experimental results showed that, with the same number of function evaluations, directed variation ES reached better optimization results for different generally used strategies under the ES framework. Experimental analysis showed that the application of directed variation could increase the expected fitness improvement and the probability of fitness improvement. From a biological perspective, directed variation can be regarded as a result of self-organizing evolution.

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2005年08月05日

【期刊论文】Performance Model of IEEE 802.11 DCF With Variable Packet Length

李衍达, Hongyuan Chen and Yanda Li, Senior Member, IEEE

IEEE COMMUNICATIONS LETTERS, VOL. 8, NO.3, MARCH 2004,-0001,():

-1年11月30日

摘要

Abstract-Few analytical models have been proposed to evaluate the hybrid of the basic and the RTS/CTS access mechanisms up to now. The main reason is that it is very difficult to study a scheme with variable packet length. In this letter, we propose a model to evaluate the saturation throughput performance of the hybrid access mechanism, assuming that the packet lengths are sampled from a general distribution function f(χ). Index Terms-IEEE 802.11, performance model, WLAN.

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2005年08月05日

【期刊论文】Characterizing self-similarity in bacteria DNA sequences

李衍达, Xin Lu, , *, Zhirong Sun, Huimin Chen, and Yanda Li

,-0001,():

-1年11月30日

摘要

In this paper some parametric methods are introduced to characterize the self-similarity of DNA sequences. Compared with Fourier analysis, these methods perform statistically more stably and yield more reliable results. Using these methods, eight whole genomes of bacteria provided by NCBI are analyzed. Long-range correlation properties in the nucleotide density distribution along these DNA sequences are explored. Estimation results show that the long-range correlation structure prevails through the entire molecule of DNA. Higher order statistics through coarse graining reveal that rather than multifractal, there are only monofractal phenomena presented in the sequences. Hence, the nucleotide density distribution can be modeled asymptotically as fractional Gaussian noise. This result points to a new direction for analyzing and understanding the intrinsic structures of DNA sequences.

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2005年08月05日

【期刊论文】Prediction of protein subcellular locations using fuzzy k-NN method

李衍达, Ying Huang*, and Yanda Li

,-0001,():

-1年11月30日

摘要

Motivation: Protein localization data are a valuable information resource helpful in elucidating protein functions. It is highly desirable to predict a protein's subcellular locations automatically from its sequence. Results: In this paper, fuzzy k-nearest neighbors (k-NN) algorithm has been introduced to predict proteins' subcellular locations from their dipeptide composition. The prediction is performed with a new data set derived from version 41.0 SWISS-PROT databank, the overall predictive accuracy about 80% has been achieved in a jackknife test. The result demonstrates the applicability of this relative simple method and possible improvement of prediction accuracy for the protein subcellular locations. We also applied this method to annotate six entirely sequenced proteomes, namely Saccharomyces cerevisiae, Caenorhabditis elegans, Drosophila melanogaster, Oryza sativa, Arabidopsis thaliana and a subset of all human proteins.

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  • 李衍达 邀请

    清华大学,北京

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