57 research outputs found
Operating characteristics for the design and optimisation of classification systems
No full textIn statistical pattern recognition, problems involve distinguishing of various concepts or classes, based on the development of classifiers/discriminators. These exploit discriminatory information existing in measurements originating from objects. A trained classifier results in a partitioning in measurement space, providing some separation between the various classes. In the (typical) case of class overlap, this partitioning inherently results in a trade-off between the various possible classification errors that may occur. This partitioning can be modified to adjust these trade-offs. Given class abundances, a classifier can be evaluated at a given partitioning. However, variations in the abundances leads to an altered classifier performance. These fundamental aspects behind classifier design and evaluation can be studied within the framework of classifier operating characteristics, which is the topic of this dissertation. The contents consist of a number of published/accepted journal and conference papers, contextualised into a number of chapters representing various aspects of operating characteristic analysis. First the well-known two-class operating characteristic is considered, with two new analyses that are useful in certain circumstances. Next, the extension to the elusive multiclass case is considered, showing how standard 2-class operating characteristics analyses can be extended theoretically to the multiclass case. The challenge behind the multiclass extension is shown to be of a computational nature, with the calculation size increasing exponentially with the number of classes. The primary thesis contribution is then presented, consisting of a number of approaches and philosophies that can be used to overcome the computational challenges. Of primary importance is the finding that most practical problems are such that not all dimensions of the operating characteristic interact together significantly. Next it is shown how the operating characteristic approach can be used to design classifiers in ill-defined environments. In these problems some classes may be poorly represented, and the goal of the classifier design is to protect against these unforeseen conditions. Finally, it is shown that operating characteristics can be applied to a multi-stage classifier setup, allowing for a holistic design incorporating interactions between classes, and the classifier stages.Electrical Engineering, Mathematics and Computer Scienc
Efficient Multiclass ROC Approximation by Decomposition via Confusion Matrix Perturbation Analysis
No full textReceiver operator characteristic (ROC) analysis has become a standard tool in the design and evaluation of two-class classification problems. It allows for an analysis that incorporates all possible priors, costs, and operating points, which is important in many real problems, where conditions are often nonideal. Extending this to the multiclass case is attractive, conferring the benefits of ROC analysis to a multitude of new problems. Even though theROCanalysis extends theoretically to the multiclass case, the exponential computational complexity as a function of the number of classes is restrictive. In this paper, we show that the multiclass ROC can often be simplified considerably because some ROC dimensions are independent of each other. We present an algorithm that analyzes interactions between various ROC dimensions, identifying independent classes, and groups of interacting classes, allowing the ROC to be decomposed. The resulting decomposed ROC hypersurface can be interrogated in a similar fashion to the ideal case, allowing for approaches such as cost sensitive and Neyman-Pearson optimization, as well as the volume under the ROC. An extensive bouquet of examples and experiments demonstrates the potential of this methodology.MediamaticsElectrical Engineering, Mathematics and Computer Scienc
Manufacturing of hybrid aluminum copper joints by electromagnetic pulse welding – Identification of quantitative process windows
No full textArt. 110001, 6 S.Compared to conventional joining techniques, electromagnetic pulse welding offers important advantages especially when it comes to dissimilar material connections as e.g. copper aluminum welds. However, due to missing guidelines and tools for process design, the process has not been widely implemented in industrial production, yet. In order to contribute to overcoming this obstacle, a combined numerical and experimental process analysis for electromagnetic pulse welding of Cu-DHP and EN AW-1050 was carried out and the results were consolidated in a quantitative collision parameter based process window
Experimental analysis of the sheet metal forming behavior of newly developed press hardening steels
No full textFood to Fuel: Anaerobic Digestion at the Rutgers New Brunswick Campus
No full textThe food waste at Rutgers New Brunswick can be converted to bio-fuel through the means of anaerobic digestionSpring 201
Identification and mapping of land use classes in Marion County (Indianapolis), Indiana by machine processing of ERTS-1 MSS data
No full textThere are no author-identified significant results in this report
[Photointerpretation of Skylab Imagery]
No full textThere are no author-identified significant results in this report
Remote sensing research studies
No full textThere are no author-identified significant results in this report
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