نتایج جستجو برای: cn2
تعداد نتایج: 347 فیلتر نتایج به سال:
Abstract Y 4 O 2 (CN ) 3 Cl and some isotypic rare earth ( RE carbodiimides = Sm, Gd, Tb) were prepared by solid-state metathesis reaction between , OCl Li CN . The crystal structure of was solved refined from single-crystal XRD data with the monocline space group C2/m Homologous compounds Tb assigned isotypically means powder diffraction. is characterized one-dimensional cluster chains which a...
Simple inductive learning algorithms assume that all attribute values are available. The well-known Quinlan's paper [Qui89] discusses quite a few routines for processing of unknown attribute values in the TDIDT family and analyzes seven of them. This paper introduces five routines for processing of unknown attribute values that have been designed for the CN4 learning algorithm, a large extensio...
Methods for constructive induction perform an automatic transformation of description spaces if representational shortcomings deteriorate the quality of learning. In the context of concept learning and propositional representation languages, feature construction algorithms have been developed in order to improve the accuracy and to decrease the complexity of hypotheses. Particularly, so-called ...
General-to-speci c learners like ID3 and CN2 perform well when the target concept descriptions are general, but often have di culties when they are speci c or mixed. This problem can be alleviated by combining them with a speci c-to-general learning component, resulting in a two-way induction system. In this paper one design for such a component is proposed, as well as two methods for combining...
OBJECTIVE The objectives of the present study were to assess the efficacy and tolerability of perioperative paclitaxel/platinum-based chemotherapy and surgery in patients with stage IIIA clinical N2 (cN2) non-small cell lung cancer (NSCLC). METHODS Clinical N2 was defined as either >15 mm or >10 mm and multiple nodes on computed tomography (CT) scan. Thirty-four chemotherapy-naive patients wi...
A new prepruning technique for rule induction is presented which applies instance reduction before rule induction. An empirical evaluation records the predictive accuracy and size of rule-sets generated from 24 datasets from the UCI Machine Learning Repository. Three instance reduction algorithms (Edited Nearest Neighbour, AllKnn and DROP5) are compared. Each one is used to reduce the size of t...
Current rule induction systems (e.g. CN2) typically rely on a \separate and conquer" strategy: they induce one rule at a time, removing the newly covered examples from the training set after each step. This results in a dwindling number of examples being available for learning successive rules, which in turn causes several problems that adversely a ect the accuracy of the resulting rules. The r...
Current methods to avoid overrtting are either data-oriented (using separate data for validation) or representation-oriented (penalizing complexity in the model). This paper proposes process-oriented evaluation, where a model's expected generalization error is computed as a function of the search process that led to it. The paper develops the necessary theoretical framework, and applies it to o...
Based on the theory for the turbulence and the Rytov method, the propagation formulas of the scintillation index and the mean square angle-of-arrival fluctuation for the beam propagation in atmospheric turbulence have been derived respectively. The propagation properties of the two turbulence effects have been investigated, and the effects of the characteristic parameters of turbulence and the ...
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