1,721,085 research outputs found
Analysis of pupil fluctuations for detection of deception
No full textThe relation between pupil fluctuation and deception is considered. The response of pupil to light or noise stimuli has been extensively studied, together with the relation between anomalous fluctuations and drug or alcohol abduction. Moreover it is known that cognitive process, fatigue and emotions have influence in pupil fluctuation and in its reaction to stimuli. Since 1940 the idea of studying the pupil movement and fluctuations as index of deception has been considered; nevertheless, since many different cognitive processes can influence pupillary dilatation, it is necessary to improve the technique and to assess the accuracy of pupil movement as such a possible parameter. The present paper analyses the pupil fluctuation, the movements of its center and the increase of the number of eye blinking in order to propose possible indicators of deception. The first results proposed appear to be encouraging; of course in all laboratory studies of deception the simulation context is different from real-life investigations; this limitation will require further development
Texture analysis of microscopic liver images by a level set approach
No full textIn this paper the analysis of liver tissue images is addressed to identify abnormal zones due to the presence of tissue with necrosis, or to malignant lymphoma; the study is performed by texture analysis. A discrete level set approach has been used, applying the well know algorithm of segmentation to a new data constituted by a linear combination of the matrices of Uniformity, Contrast and Entropy. The method proposed in this paper makes use of the classification capability of the discrete level set analysis applied to a suitable transformation of the original data. The algorithm is applied to a significant set of liver tissue, showing encouraging results
Analysis of pupil fluctuations after a light stimulus by image processing and neural network
No full textIn this paper the analysis of pupil fluctuations after a light stimulus is considered; it is useful for non-invasive diagnosis of many different diseases. When a light stimulus is presented to a subject, the pupil response is not instantaneous because of the action of the sphincter muscle. A sequence of images will be caught by a pupillometer and each image of the sequence will be binarized; for each segmented image, a useful parameter will be considered, the major diameter that is the length (in pixels) of the major axis of the ellipse that has the same second moments of the pupil. The aim is the identification of the response time after a light stimulus, from the sequence of the major diameters. The considered signal is degraded because of the presence of the measurement noise, the natural fluctuation of the pupil (usually called “pupil noise”), and the general health state of the subject. To enhance the significant part of this noisy signal a neural network is suitable trained. From the clean signal the identification of the response time of the pupil will be easier and a simple method will be proposed
A dynamical model of cell population with quiescence fromG1 phase: analysis of cell loss in the estimation of the potential doubling time
No full textWe propose two cell population models with non uniform cell-loss; in the fiorst one instantaneous non-uniform loss occurs, in the second one non uniform and non instantaneous loss is considered
Some results about the optimal LQG tracking problem
No full textThe optimal LQG tracking problem is studied both for available and for unavailable state and reference, assuming that the last variable is the addition of a known deterministic component and of a random noise component. In both cases the optimal solution exists, is unique, and the optimal control is a suitable a ne function of the current state and reference variable (when they are available) or of the corresponding optimal estimates (when they are not available). The minimum cost function is expressed in closed for
Fixed/free final time sir epidemic models with multiple controls
No full textIn this paper the possible advantages in introducing multiple controls in the analysis of epidemic models are investigated. Usually, only the susceptible or infected people are controlled by vaccination or by quarantine and/or medicine treatment; in this paper multiple controls, both for the susceptible and infected are considered. The problem is studied both in the case of fixed and free final time. Numerical results are considered for simulated data showing the effects of multiple controls and the rule of each parameters of the model. Also a simulation on real data regarding the course of measles in Africa is presented
Identification of suspicious masses in mammography
No full textA study on mammographic images is proposed to characterize non suspicious zones and cancerous ones. In particular, the attention has been devoted to ductal carcinoma. It is one of the leading cause of death for women and early diagnosis significantly reduces breast cancer mortality.
In this paper properties like mean values, standard deviation, correlation, contrast, energy and homogeneity are evaluated. The images are segmented on the basis of this information in order to identify and enhance suspicious zones. These zones are characterized also by their morphological properties, such as their extension and the raggedness of their contours. The proposed analysis has been tested on mammographic images for which the diagnosis of an expert was available. The numerical results show a significant success in cancerous zones identification
Parametric characterization of the form of the human pupil from blurred noisy images
No full textThe fluctuation of the human pupil is an important parameter in order to make non-invasive diagnosis of many different diseases and in several clinical applications. The relevant measurement device, the pupillometer, consists in a CCD camera, which shoots the pupil. We suppose that the measured image is blurred by a Gaussian kernel and corrupted by an additive white noise; moreover an elliptic shape for the pupil is assumed. We here present the extension of a multiscale approach for edge detection to identify some parameters of the pupil: the location of its centre, the length of the semi-axes and the orientation of the corresponding ellipse. The chosen method requires knowledge about the degradation parameters of the assumed model; so we first present a simple but efficient method to determine such quantities for the measured image. Then we apply the edge detection procedure to identify points close to the pupil edge, within a chosen probability. Finally we find the optimal ellipse fitting a suitable subset of the previously detected edge points. Results are presented, with comparisons to other approaches for edge finding
A study on abnormality in variational and optimal control problems
No full textIn this paper, a variational problem is considered with differential equality constraints over a variable interval. It is stressed that the abnormality is a local character of the admissible set; consequently, a definition of regularity related to the constraints characterizing the admissible set is given. Then, for the local minimum necessary conditions, a compact form equivalent to the well-known Euler equation and transversality condition is given. By exploiting this result and the previous definition of regularity, it is proved that nonregularity is a necessary and sufficient condition for an admissible solution to be an abnormal extremal. Then, a necessary and sufficient condition is given for an abnormal extremal to be weakly abnormal. The analysis of the abnormality is completed by considering the particular case of affine constraints over a fixed interval: in this case, the abnormality turns out to have a global character, so that it is possible to define an abnormal problem or a normal problem. The last section is devoted to the study of an optimal control problem characterized by differential constraints corresponding to the dynamics of a controlled process. The above general results are particularized to this problem, yielding a necessary and sufficient condition for an admissible solution to be an abnormal extremal. From this, a previously known result is recovered concerning the linearized system controllability as a sufficient condition to exclude the abnormality
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