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  • 1
    Digitale Medien
    Digitale Medien
    Tracking Drifting Concepts By Minimizing Disagreements (1994)
    Springer
    Machine learning 14 (1994), S. 27-45 
    Details
    ISSN: 0885-6125
    Schlagwort(e): Computational learning theory ; concept drift ; concept learning
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Informatik
    Notizen: Abstract In this paper we consider the problem of tracking a subset of a domain (called the target) which changes gradually over time. A single (unknown) probability distribution over the domain is used to generate random examples for the learning algorithm and measure the speed at which the target changes. Clearly, the more rapidly the target moves, the harder it is for the algorithm to maintain a good approximation of the target. Therefore we evaluate algorithms based on how much movement of the target can be tolerated between examples while predicting with accuracy ε Furthermore, the complexity of the class $$\mathcal{H}$$ of possible targets, as measured by d, its VC-dimension, also effects the difficulty of tracking the target concept. We show that if the problem of minimizing the number of disagreements with a sample from among concepts in a class $$\mathcal{H}$$ can be approximated to within a factor k, then there is a simple tracking algorithm for $$\mathcal{H}$$ which can achieve a probability ε of making a mistake if the target movement rate is at most a constant times $$ \in ^2 /(k(d + k)\ln \frac{1}{ \in })$$ , where d is the Vapnik-Chervonenkis dimension of $$\mathcal{H}$$ . Also, we show that if $$\mathcal{H}$$ is properly PAC-learnable, then there is an efficient (randomized) algorithm that with high probability approximately minimizes disagreements to within a factor of 7d + 1, yielding an efficient tracking algorithm for $$\mathcal{H}$$ which tolerates drift rates up to a constant times $$ \in ^2 /(d^2 \ln \frac{1}{ \in })$$ . In addition, we prove complementary results for the classes of halfspaces and axis-aligned hyperrectangles showing that the maximum rate of drift that any algorithm (even with unlimited computational power) can tolerate is a constant times ε2/d.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1022694620923
    Standort Signatur Erwartet Verfügbarkeit
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    Artikel (Nationallizenzen)
    Volltext
  • 2
    Digitale Medien
    Digitale Medien
    Tracking drifting concepts by minimizing disagreements (1994)
    Springer
    Machine learning 14 (1994), S. 27-45 
    Details
    ISSN: 0885-6125
    Schlagwort(e): Computational learning theory ; concept drift ; concept learning
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Informatik
    Notizen: Abstract In this paper we consider the problem of tracking a subset of a domain (called thetarget) which changes gradually over time. A single (unknown) probability distribution over the domain is used to generate random examples for the learning algorithm and measure the speed at which the target changes. Clearly, the more rapidly the target moves, the harder it is for the algorithm to maintain a good approximation of the target. Therefore we evaluate algorithms based on how much movement of the target can be tolerated between examples while predicting with accuracy ε. Furthermore, the complexity of the classH of possible targets, as measured byd, its VC-dimension, also effects the difficulty of tracking the target concept. We show that if the problem of minimizing the number of disagreements with a sample from among concepts in a classH can be approximated to within a factork, then there is a simple tracking algorithm forH which can achieve a probability ε of making a mistake if the target movement rate is at most a constant times ε2/(k(d +k) ln 1/ε), whered is the Vapnik-Chervonenkis dimension ofH. Also, we show that ifH is properly PAC-learnable, then there is an efficient (randomized) algorithm that with high probability approximately minimizes disagreements to within a factor of 7d + 1, yielding an efficient tracking algorithm forH which tolerates drift rates up to a constant times ε2/(d 2 ln 1/ε). In addition, we prove complementary results for the classes of halfspaces and axisaligned hyperrectangles showing that the maximum rate of drift that any algorithm (even with unlimited computational power) can tolerate is a constant times ε2/d.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00993161
    Standort Signatur Erwartet Verfügbarkeit
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    Artikel (Nationallizenzen)
    Volltext
  • 3
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    Unbekannt
    Naturally occurring variation in bristle number and DNA polymorphisms at the scabrous locus of Drosophila melanogaster (1994)
    American Association for the Advancement of Science (AAAS)
    Details
    Publikationsdatum: 1994-12-09
    Beschreibung: The association between quantitative genetic variation in bristle number and molecular variation at a candidate neurogenic locus, scabrous, was examined in Drosophila melanogaster. Approximately 32 percent of the genetic variation in abdominal bristle number (21 percent for sternopleural bristle number) among 47 second chromosomes from a natural population was correlated with DNA sequence polymorphisms at this locus. Several polymorphic sites associated with large phenotypic effects occurred at intermediate frequency. Quantitative genetic variation in natural populations caused by alleles that have large effects at a few loci and that segregate at intermediate frequencies conflicts with the classical infinitesimal model of the genetic basis of quantitative variation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lai, C -- Lyman, R F -- Long, A D -- Langley, C H -- Mackay, T F -- GM45146/GM/NIGMS NIH HHS/ -- GM45344/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Dec 9;266(5191):1697-702.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Center for Population Biology, University of California at Davis 95616.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7992053" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Alleles ; Animals ; Base Sequence ; DNA/genetics ; *Drosophila Proteins ; Drosophila melanogaster/anatomy & histology/*genetics ; Female ; *Genes, Insect ; *Genetic Variation ; *Glycoproteins ; Haplotypes ; Linkage Disequilibrium ; Male ; Molecular Sequence Data ; Phenotype ; *Polymorphism, Genetic ; Proteins/*genetics ; Restriction Mapping ; Sense Organs/anatomy & histology
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Publiziert von American Association for the Advancement of Science (AAAS)
    Standort Signatur Erwartet Verfügbarkeit
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