From Data Topology to a Modular Classifier

This article describes an approach to designing a distributed and modular neural classifier. This approach introduces a new hierarchical clustering that enables one to determine reliable regions in the representation space by exploiting supervised information. A multilayer perceptron is then associated with each of these detected clusters and charged with recognizing elements of the associated cluster while rejecting all others. The obtained global classifier is comprised of a set of cooperating neural networks and completed by a K-nearest neighbor classifier charged with treating elements rejected by all the neural networks. Experimental results for the handwritten digit recognition problem and comparison with neural and statistical nonmodular classifiers are given

PIRANTI LUNAK UNTUK ANALISIS BENTUK LENGKUNG GIGI DENGAN JARINGAN SARAF TIRUAN

In this paper, dental arch form classification system using back propagation algorithm is proposed. Some features of dental arch are selected for neural network input based on statistical analysis to dependent variables of dental arch. The system contains some features for training and testing the neural network, and for recognizing the arch form based on input parameters. The experiment uses randomly selected data set contains 190 numerical data of upper dental arch that are extracted from dental model images. The images were obtained by scanning the original 3D dental models of Indonesian patient that were collected from some orthodontic clinics in Jakarta. This experimental result shows that 76,3158% of correctness in classifying the arch form can be reached by neural network system. The system can be applied for supporting the orthodontic treatment. Abstract in Bahasa Indonesia : Dalam tulisan ini, dipaparkan hasil pengembangan system klasifikasi bentuk lengkung gigi berbasis algoritma propagasi balik jaringan saraf tiruan. Sejumlah fitur bentuk lengkung gigi dipilih sebagai input jaringan saraf tiruan berdasarkan hasil pengujian secara statistik terhadap variabel bentuk lengkung gigi. Piranti lunak dikembangkan terdiri dari sejumlah fitur yang digunakan untuk pengujian dan pelatihan JST, serta pengenalan bentuk lengkung berdasarkan parameter input yang diberikan oleh peng-guna. Eksperimen dilakukan terhadap data numerik hasil ekstraksi citra digital model cetakan lengkung gigi rahang atas sejumlah 190 orang pasien yang diambil secara acak. Citra lengkung gigi diperoleh dengan melakukan pemindaian terhadap model cetakan lengkung gigi tiga dimensi (3D) pasien ortodonti disejumlah klinik di Jakarta. Hasil uji coba menunjukkan bahwa 76,3158% berhasil diklasifikasikan dengan benar oleh sistem berbasis JST tersebut. Ke depannya sistem akan dikembangkan lebih optimal sehingga dapat diguna- kan untuk mendukung perawatan ortodonti

Combining Model-based and Discriminative Approaches in a Modular Two-stage Classification System: Application to Isolated Handwritten Digit Recognition

The motivation of this work is based on two key observations. First, the classification algorithms can be separated into two main categories: discriminative and model-based approaches. Second, two types of patterns can generate problems: ambiguous patterns and outliers. While, the first approach tries to minimize the first type of error, but cannot deal effectively with outliers, the second approach, which is based on the development of a model for each class, make the outlier detection possible, but are not sufficiently discriminant. Thus, we propose to combine these two different approaches in a modular two-stage classification system embedded in a probabilistic framework. In the first stage we pre-estimate the posterior probabilities with a model-based approach and we re-estimate only the highest probabilities with appropriate Support Vector Classifiers (SVC) in the second stage. Another advantage of this combination is to reduce the principal burden of SVC, the processing time necessary to make a decision and to open the way to use SVC in classification problem with a large number of classes. Finally, the first experiments on the benchmark database MNIST have shown that our dynamic classification process allows to maintain the accuracy of SVCs, while decreasing complexity by a factor 8.7 and making the outlier rejection available

Are multilayer perceptrons adequate for pattern recognition and verification?

2reservedmixedGORI M.; SCARSELLI F.Gori, Marco; Scarselli, Franc

Advanced eddy current test signal analysis for steam generator tube defect classification and characterization

Eddy Current Testing (ECT) is a Non-Destructive Examination (NDE) technique that is widely used in power generating plants (both nuclear and fossil) to test the integrity of heat exchanger (HX) and steam generator (SG) tubing. Specifically for this research, laboratory-generated, flawed tubing data were examined The tubing data were acquired from the EPRI NDE Center, Charlotte, NC. The data are catalogued in the Performance Demonstration Database (POD) which is used as a training manual for certification. The specific subset of the data used in this dissertation has an Examination Technique Specification Sheet (ETSS) and a blueprint of the flawed tube specimens. The purpose of this dissertation is to develop and implement an automated method for the classification and an advanced characterization of defects in HX and SG tubing. These two improvements enhanced the robustness of characterization as compared to traditional bobbin-coil ECT data analysis methods. A more robust classification and characterization of the tube flaw insitu (while the SG is on-line but not when the plant is operating), should provide valuable information to the power industry. The following is a summary of the original contributions of this dissertation research. 1. Development of a feature extraction program acquiring relevant information from both the mixed, absolute and differential ECTD Flaw Signal (ECTDFS). 2. Application of the Continuous Wavelet Transformation (CWT) to extract more information from the mixed, complex differential ECTDFS. 3. Utilization of Image Processing (IP) techniques to extract the information contained in the generated CWT. 4. Classification of the ECTDFSs, using the compressed feature vector and a Bayes classification system. 5. Development of an upper bound for the probability of classification error, using the Bhattacharyya distance, for the Bayesian classification. 6. Tube defect characterization based on the classified flaw-type to enhance characterization 7. Development of a diagnostic software system EddyC and user\u27s guide. The important results of the application of the method are listed. The CWT contains at least enough information to correctly classify the flaws 64% of the time using the IP features. The Bayes classification system, using only the CWT generated features (after PCA compression), correctly identified 64% of the ECTD flaws. The Bayes classification system correctly identified 7 5% of the ECTD flaws using cross validation utilizing all the generated features after PCA compression. Initial template matching results (from the PDD database) yielded correct classification of 69%. The B-distances parallel and bound the percent misclassified cases. The calculated B-distance for 15 PCs were O and 14.22% bounding the 1.1% incorrectly classified. But, these Gaussian-based calculated B-distances may be inaccurate due to non-Gaussian features. The number of outliers seems to have an inverse relationship with the number of misclassifications. Characterization yielded an average error of 12.76 %. This excluded the results from flaw-type 1 (Thinning). The following are the conclusions reached from this research. A feature extraction program acquiring relevant information from both the mixed, absolute and differential data was successfully implemented. The CWT was utilized to extract more information from the mixed, complex differential data. Image Processing techniques used to extract the information contained in the generated CWT, classified the data with a high success rate. The data were accurately classified, utilizing the compressed feature vector and using a Bayes classification system. An estimation of the upper bound for the probability of error, using the Bhattacharyya distance, was successfully applied to the Bayesian classification. The classified data were separated according to flaw-type (classification) to enhance characterization. The characterization routine used dedicated, flaw-type specific ANNs that made the characterization of the tube flaw more robust. The inclusion of outliers may help complete the feature space so that classification accuracy is increased. Given that the eddy current test signals appear very similar, there may not be sufficient information to make an extremely accurate (\u3e 95%) classification or an advanced characterization using this system. It is necessary to have a larger database fore more accurate system learning