1,354 research outputs found

    Efficient Optimization of Performance Measures by Classifier Adaptation

    Full text link
    In practical applications, machine learning algorithms are often needed to learn classifiers that optimize domain specific performance measures. Previously, the research has focused on learning the needed classifier in isolation, yet learning nonlinear classifier for nonlinear and nonsmooth performance measures is still hard. In this paper, rather than learning the needed classifier by optimizing specific performance measure directly, we circumvent this problem by proposing a novel two-step approach called as CAPO, namely to first train nonlinear auxiliary classifiers with existing learning methods, and then to adapt auxiliary classifiers for specific performance measures. In the first step, auxiliary classifiers can be obtained efficiently by taking off-the-shelf learning algorithms. For the second step, we show that the classifier adaptation problem can be reduced to a quadratic program problem, which is similar to linear SVMperf and can be efficiently solved. By exploiting nonlinear auxiliary classifiers, CAPO can generate nonlinear classifier which optimizes a large variety of performance measures including all the performance measure based on the contingency table and AUC, whilst keeping high computational efficiency. Empirical studies show that CAPO is effective and of high computational efficiency, and even it is more efficient than linear SVMperf.Comment: 30 pages, 5 figures, to appear in IEEE Transactions on Pattern Analysis and Machine Intelligence, 201

    Developing Student Model for Intelligent Tutoring System

    Get PDF
    The effectiveness of an e-learning environment mainly encompasses on how efficiently the tutor presents the learning content to the candidate based on their learning capability. It is therefore inevitable for the teaching community to understand the learning style of their students and to cater for the needs of their students. One such system that can cater to the needs of the students is the Intelligent Tutoring System (ITS). To overcome the challenges faced by the teachers and to cater to the needs of their students, e-learning experts in recent times have focused in Intelligent Tutoring System (ITS). There is sufficient literature that suggested that meaningful, constructive and adaptive feedback is the essential feature of ITSs, and it is such feedback that helps students achieve strong learning gains. At the same time, in an ITS, it is the student model that plays a main role in planning the training path, supplying feedback information to the pedagogical module of the system. Added to it, the student model is the preliminary component, which stores the information to the specific individual learner. In this study, Multiple-choice questions (MCQs) was administered to capture the student ability with respect to three levels of difficulty, namely, low, medium and high in Physics domain to train the neural network. Further, neural network and psychometric analysis were used for understanding the student characteristic and determining the student’s classification with respect to their ability. Thus, this study focused on developing a student model by using the Multiple-Choice Questions (MCQ) for integrating it with an ITS by applying the neural network and psychometric analysis. The findings of this research showed that even though the linear regression between real test scores and that of the Final exam scores were marginally weak (37%), still the success of the student classification to the extent of 80 percent (79.8%) makes this student model a good fit for clustering students in groups according to their common characteristics. This finding is in line with that of the findings discussed in the literature review of this study. Further, the outcome of this research is most likely to generate a new dimension for cluster based student modelling approaches for an online learning environment that uses aptitude tests (MCQ’s) for learners using ITS. The use of psychometric analysis and neural network for student classification makes this study unique towards the development of a new student model for ITS in supporting online learning. Therefore, the student model developed in this study seems to be a good model fit for all those who wish to infuse aptitude test based student modelling approach in an ITS system for an online learning environment. (Abstract by Author

    Radial Basis Function Neural Networks : A Review

    Get PDF
    Radial Basis Function neural networks (RBFNNs) represent an attractive alternative to other neural network models. One reason is that they form a unifying link between function approximation, regularization, noisy interpolation, classification and density estimation. It is also the case that training RBF neural networks is faster than training multi-layer perceptron networks. RBFNN learning is usually split into an unsupervised part, where center and widths of the Gaussian basis functions are set, and a linear supervised part for weight computation. This paper reviews various learning methods for determining centers, widths, and synaptic weights of RBFNN. In addition, we will point to some applications of RBFNN in various fields. In the end, we name software that can be used for implementing RBFNNs

    Face Recognition Methodologies Using Component Analysis: The Contemporary Affirmation of The Recent Literature

    Get PDF
    This paper explored the contemporary affirmation of the recent literature in the context of face recognition systems, a review motivated by contradictory claims in the literature. This paper shows how the relative performance of recent claims based on methodologies such as PCA and ICA, which are depend on the task statement. It then explores the space of each model acclaimed in recent literature. In the process, this paper verifies the results of many of the face recognition models in the literature, and relates them to each other and to this work

    Machine learning-based motion type classification from 5G data

    Get PDF
    Abstract. To improve the quality of their services and products, nowadays every industry is using artificial intelligence and machine learning. Machine learning is a powerful tool that can be applied in many applications including wireless communications. One way to improve the reliability of wireless connections is to classify motion type of the user and hook it with beamforming and beam steering. With the user equipment’s motion type classification ability, the base station can allocate proper beamforming to the given class of users. With this motivation, the studies of ML algorithms for motion classification is conducted in this thesis. In this work, the supervised learning technique is used to predict and classify motion types using the 5G data. In this work, we used the 5G data collected in 4 different scenarios or classes which are (i) Walking (ii) Standing (ii) Driving and (iv) Drone. The data is then operated on for cleaning and feature engineering and then is fed into different classification algorithms including Logistic Regression Cross Validation (LRCv), Support Vector Classifier (SVC), k-nearest neighbors (KNN), Linear Discriminant Analysis (LDA), AdaBoost, and Extra Tree Classifier. Upon analyzing the evaluation metrics for these algorithms, we found that with the accuracy of ~99% and log-loss of 0.044, Extra Tree Classifier performed better than others. With such promising results, the output of classification process can be used in another pipeline for resource optimization or hooked with hardware for beamforming and beam steering. It can also be used as an input to a digital twin of radio to change its variables dynamically which will be reflected in the physical copy of that radio
    corecore