Akinokree To solve these problems, a new modified algorithm based on interval similarity is proposed. This time, merged standard of extended Chi2 algorithm is possibly more accurate in computation. Under the comparison for two methods, the difference of recognition and forecast effect of Auto and Iris datasets each of them has three classes is small. This is discretlzation open access article distributed under the Creative Commons Attribution Licensedidcretization permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Having the data ready in our hands, we can now proceed to implement the ChiSquare function which is basically an implementation of the formula: But in fact, adjacent two intervals with the bigger difference of class distribution and the greater number of classes should not be first merged.
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Many supervised machine learning algorithms require a discrete feature space. In this paper, we review previous work on continuous feature discretization, identify de n-ing characteristics of the methods, and conduct an empirical evaluation of several methods. We compare binning, an unsupervised dis We compare binning, an unsupervised discretization method, to entropy-based and purity-based methods, which are supervised algorithms.
We found that the performance of the Naive-Bayes algorithm signi cantly improved when features were discretized using an entropy-based method. In fact, over the 16 tested datasets, the discretized version of Naive-Bayes slightly outperformed C4. We also show that in some cases, the performance of the C4. In some cases this could make effective classification much more difficult.
A variation of equal frequency intervalsmaximal marginal entropy adjusts the boundaries to decrease entropy at each Douglas Baker, Andrew Kachites Mccallum , " This paper describes the application of Distributional Clustering  to document classification. This approach clusters words into groups based on the distribution of class labels associated with each word.
Thus, unlike some other unsupervised dimensionalityreduction techniques, such as Latent Sem Thus, unlike some other unsupervised dimensionalityreduction techniques, such as Latent Semantic Indexing, we are able to compress the feature space much more aggressively, while still maintaining high document classification accuracy. We also show that less aggressive clustering sometimes results in improved classification accuracy over classification without clustering.
Murthy - Data Mining and Knowledge Discovery , " Decision trees have proved to be valuable tools for the description, classification and generalization of data. Work on constructing decision trees from data exists in multiple disciplines such as statistics, pattern recognition, decision theory, signal processing, machine learning and artificial ne Work on constructing decision trees from data exists in multiple disciplines such as statistics, pattern recognition, decision theory, signal processing, machine learning and artificial neural networks.
Researchers in these disciplines, sometimes working on quite different problems, identified similar issues and heuristics for decision tree construction.
This paper surveys existing work on decision tree construction, attempting to identify the important issues involved, directions the work has taken and the current state of the art. Keywords: classification, tree-structured classifiers, data compaction 1. Introduction Advances in data collection methods, storage and processing technology are providing a unique challenge and opportunity for automated data exploration techniques.
Enormous amounts of data are being collected daily from major scientific projects e. Show Context Citation Context The problem of incorporating continuous attributes into these algorithms is considered subsequently. Fast methods for splitting a continuous dimension into more than two ranges is considered in the machine learning literature [, ].
Discrete values have important roles in data mining and knowledge discovery. They are about intervals of numbers which are more concise to represent and specify, easier to use and comprehend as they are closer to a knowledge-level representation than continuous values.
Many studies show induction t Many studies show induction tasks can benefit from discretization: rules with discrete values are normally shorter and more understandable and discretization can lead to improved predictive accuracy.
Furthermore, many induction algorithms found in the literature require discrete features. All these prompt researchers and practitioners to discretize continuous features before or during a machine learning or data mining task. There are numerous discretization methods available in the literature. It is time for us to examine these seemingly different methods for discretization and find out how different they really are, what are the key components of a discretization process, how we can improve the current level of research for new development as well as the use of existing methods.
This paper aims at a systematic study of discretization methods with their history of development, effect on classification, and trade-off between speed and accuracy. Contributions of this paper are an abstract description summarizing existing discretization methods, a hierarchical framework to categorize the existing methods and pave the way for further development, concise discussions of representative discretization methods, extensive experiments and their analysis, and some guidelines as to how to choose a discretization method under various circumstances.
We also identify some issues yet to solve and future research for discretization. Classification of large datasets is an important data mining problem. Many classification algorithms have been proposed in the literature, but studies have shown that so far no algorithm uniformly outperforms all other algorithms in terms of quality. In this paper, we present a unifying framework fo In this paper, we present a unifying framework for decision tree classifiers that separates the scalability aspects of algorithms for constructing a decision tree from the central features that determine the quality of the tree.
This generic algorithm is easy to instantiate with specific algorithms from the literature including C4. Deriving classification rules or decision trees from examples is an important problem. When there are too many features, discarding weak features before the derivation process is highly desirable. When there are numeric features, they need to be discretized for the rule generation. We present a ne We present a new approach to these problems.
Traditional techniques make use of feature merits based on either the information theoretic or statistical correlation between each feature and the class. The merits are then used to rank the features, select a feature subset, and to discretize the numeric variables.
Experience with benchmark example sets demonstrates that the new approachisapowerful alternative to the traditional methods. This paper concludes by posing some new technical issues that arise from this approach.
Although backpropagation neural networks generally predict better than decision trees do for pattern classification problems, they are often regarded as black boxes, i. In many applications, more often than not, explicit knowled In many applications, more often than not, explicit knowledge is needed by human experts.
This work derives symbolic representations from a neural network to make epxlicit each prediction of the network. An algorithm is proposed and implemented to extract symbolic rules from neural networks. Let w; v be the weights of this network. Retrain the network.
If classificatio This paper describes a method for selecting training examples for a partial memory learning system. The method selects extreme examples that lie at the boundaries of concept descriptions and uses these examples with new training examples to induce new concept descriptions. Forgetting mechanisms al Forgetting mechanisms also may be active to remove examples from partial memory that are irrelevant or outdated for the learning task.
Using an implementation of the method, we conducted a lesion study and a direct comparison to examine the effects of partial memory learning on predictive accuracy and on the number of training examples maintained during learning. These experiments involved the STAGGER Concepts, a synthetic problem, and two real-world problems: a blasting cap detection problem and a computer intrusion detection problem. Experimental results suggest that the partial memory learner notably reduced memory requirements at the slight expense of predictive accuracy, and tracked concept drift as well as ot Discretization of continuous attributes into ordered discrete attributes can be beneficial even for propositional induction algorithms that are capable of handling continuous attributes directly.
Benefits include possibly large improvements in induction time, smaller sizes of induced trees or rule s Benefits include possibly large improvements in induction time, smaller sizes of induced trees or rule sets, and even improved predictive accuracy. We define a global evaluation measure for discretizations based on the so-called Minimum Description Length MDL principle from information theory.
Furthermore we describe the efficient algorithmic usage of this measure in the MDL-Disc algorithm. The new method solves some problems of alternative local measures used for discretization. Empirical results in a few natural domains and extensive experiments in an artificial domain show that MDL-Disc scales up well to large learning problems involving noise. Hybrid Intelligent Systems that combine knowledge based and artificial neural network systems typically have four phases involving domain knowledge representation, mapping of this knowledge into an initial connectionist architecture, network training and rule extraction respectively.
The final phase The final phase is important because it can provide a trained connectionist architecture with explanation power and validate its output decisions. Moreover, it can be used to refine and maintain the initial knowledge acquired from domain experts.
In this paper, we present three rule extraction techniques. The first technique extracts a set of binary rules from any type of neural network.
The other two techniques are specific to feedforward networks with a single hidden layer of sigmoidal units. Technique 2 extracts partial rules that represent the most important embedded knowledge with an adjustable level of detail, while the third technique provides a more comprehensive and universal approach. A rule eval Full-RE uses the Chi2  algorithm 2 , a powerful discretization tool, to compute discretization boundaries of input features.
ChiMerge 算法: 以鸢尾花数据集为例
CHIMERGE DISCRETIZATION OF NUMERIC ATTRIBUTES PDF