Controlling chaos based on a novel intelligent integral terminal sliding mode control in a rod-type plasma torch

An integral terminal sliding mode controller is proposed in order to control chaos in a rod-type plasma torch system.In this method, a new sliding surface is defined based on a combination of the conventional sliding surface in terminal sliding mode control and a nonlinear function of the integral of the system states. It is assumed that the dynamics of a chaotic system are unknown and also the system is exposed to disturbance and unstructured uncertainty. To achieve a chattering-free and high-speed response for such an unknown system, an adaptive neuro-fuzzy inference system is utilized in the next step to approximate the unknown part of the nonlinear dynamics. Then, the proposed integral terminal sliding mode controller stabilizes the approximated system based on Lyapunov＇s stability theory. In addition, a Bee algorithm is used to select the coefficients of integral terminal sliding mode controller to improve the performance of the proposed method. Simulation results demonstrate the improvement in the response speed, chattering rejection, transient response,and robustness against uncertainties.

Issues in the Mining of Heart Failure Datasets

This paper investigates the characteristics of a clinical dataset using a combination of feature selection and classification methods to handle missing values and understand the underlying statistical characteristics of a typical clinical dataset. Typically, when a large clinical dataset is presented, it consists of challenges such as missing values, high dimensionality, and unbalanced classes. These pose an inherent problem when implementing feature selection and classification algorithms. With most clinical datasets, an initial exploration of the dataset is carried out, and those attributes with more than a certain percentage of missing values are eliminated from the dataset. Later, with the help of missing value imputation, feature selection and classification algorithms, prognostic and diagnostic models are developed. This paper has two main conclusions: 1) Despite the nature of clinical datasets, and their large size, methods for missing value imputation do not affect the final performance. What is crucial is that the dataset is an accurate representation of the clinical problem and those methods of imputing missing values are not critical for developing classifiers and prognostic/diagnostic models. 2) Supervised learning has proven to be more suitable for mining clinical data than unsupervised methods. It is also shown that non-parametric classifiers such as decision trees give better results when compared to parametric classifiers such as radial basis function networks(RBFNs).

Algorithm fusion to improve detection of lung cancer on chest radiographs

Purpose-The purpose of this paper is to show an efficient method for the detection of signs of early lung cancer.Various image processing algorithms are presented for different types of lesions,and a scheme is proposed for the combination of results.Design/methodology/approach-A computer aided detection(CAD)scheme was developed for detection of lung cancer.It enables different lesion enhancer algorithms,sensitive to specific lesion subtypes,to be used simultaneously.Three image processing algorithms are presented for the detection of small nodules,large ones,and infiltrated areas.The outputs are merged,the false detection rate is reduced with four separated support vector machine(SVM)classifiers.The classifier input comes from a feature selection algorithm selecting from various textural and geometric features.A total of 761 images were used for testing,including the database of the Japanese Society of Radiological Technology(JSRT).Findings-The fusion of algorithms reduced false positives on average by 0.6 per image,while the sensitivity remained 80 per cent.On the JSRT database the system managed to find 60.2 per cent of lesions at an average of 2.0 false positives per image.The effect of using different result evaluation criteria was tested and a difference as high as 4 percentage points in sensitivity was measured.The system was compared to other published methods.Originality/value-The study described in the paper proves the usefulness of lesion enhancement decomposition,while proposing a scheme for the fusion of algorithms.Furthermore,a new algorithm is introduced for the detection of infiltrated areas,possible signs of lung cancer,neglected by previous solutions.

Dimensionality reduction of hyperspectral images of vegetation and crops based on self-organized maps

Hyperspectral images are multidimensional massive sets of information that have shown a great potential for different kind of applications as urban mapping,environmental management,vegetation and crops supervision and mineral detection.However,due to its high dimensional nature and the high variability of the spectral information,the dimensionality reduction process is one of the main challenges in processing hyperspectral images.The aim of dimensionality reduction is to eliminate redundant information and simplify the subsequent processes of classification and the search of information.In this context,several dimensionality reduction methods have been proposed,but most of them are not flexible enough to deal with the particular features of the hyperspectral images.In this way,the use of intelligent methods as neural networks and specially an unsupervised approach as self-organized maps,may improve the dimensionality reduction stage and the final classification process.This paper proposes an unsupervised method for the dimensionality reduction of hyperspectral images based on Kohonen self-organized maps,which,compared with other traditional methods such as principal component analysis(PCA)and wavelet decomposition,provides better classification results.The results provided in this paper use an RBF(radial basis function)classifier.On average,the proposed method provides a 64%dimensionality reduction and an 88.5%classification accuracy.These results suggest that the dimensionality reduction algorithm based on self-organized maps is an efficient approach compared with other popular algorithms.This is due to the ability of self-organized maps to automatically detect(self-organizing)relationships within the set of input patterns,which provides flexibility to deal with the special features of the hyperspectral images.