163 research outputs found

    Feature Based Segmentation of Colour Textured Images using Markov Random Field Model

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    The problem of image segmentation has been investigated with a focus on colored textured image segmentation.Texture is a substantial feature for the analysis of different types of images. Texture segmentation has an assortment of important applications ranging from vision guided autonomous robotics and remote sensing to medical diagnosis and retrieval in large image databases. But the main problem with the textured images is that they contain texture elements of various sizes and in some cases each of which can itself be textured.Thus the texture image segmentation is widely discerned as a difficult and thought-provoking problem.In this thesis an attempt has been made to devise methodologies for automated color textured image segmentation scheme. This problem has been addressed in the literature, still many key open issues remain to be investigated. As an initial step in this direction, this thesis proposes two methods which address the problem of color texture image segmentation through feature extraction approach in partially supervised approach.The feature extraction approaches can be classified into feature based and model based techniques.In feature based technique features are assessed without any model in mind. But in case of model based approach an inherent mathematical model lets eatures to be measured by fitting the model to the texture.The inherent features of the texture are captured in a set of parameters in order to understand the properties generating the texture. Nevertheless, a clear distinction can not be made between the two approaches and hence a combination of approaches from different categories is frequently adopted. In textured image segmentation, image model assumes a significant role and is developed by capturing salient spatial properties of an image. Markov random field (MRF)theory provides a convenient and consistent way to model context dependent entities.In this context a new scheme is proposed using Gaussian MRF model where the segmentation problem is formulated as a pixel labeling problem.The a priori class labels are modeled as Markov random field model and the number of classes is known a priori in partially supervised framework.The image label estimation problem is cast in Bayesian framework using Maximum a Posteriori (MAP)criterion and the MAP estimates of the image labels are obtained using iterated conditional modes (ICM) algorithm. Though the MRF model takes into account the local spatial interactions, it has a limitation in modeling natural scenes of distinct regions. Hence in our formulation, the first scheme takes into account within and between color plane interactions to incorporate spectraland contextual features. Genetic algorithm is employed for the initialization of ICM algorithm to obtain MAP estimates of image labels. The faster convergence property of the ICM algorithm and global convergence property of genetic algorithm are hybridized to obtain segmentation with better accuracy as well as faster convergence

    Complexity Study and Chaos Control in a Prey-Predator System

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    A prey-predator system has been investigated with the application of random shock. Since the fluctuations of populations are random, the applied shock is also assumed like a random noise. To study complexities during evolution, numerical simulations have been carried out for both cases, without shock and with shock. Stabilities of fixed points have been discussed for both the cases. Also, bifurcation diagrams for both the cases have been drawn by varying a parameter while keeping other parameters fixed. Numerical calculations have been extended to obtain plots of Lyapunov exponents and topological entropies as the measure of complexity in the system. It has been observed that the random shock has little impact to reduce the chaotic motion in the system. Then, certain periodic changes in a parameter have been allowed to some extent,this results in bringing the system from chaos to regularity. Such changes may happen naturally in a prey-predator system and so there exists the possibility of coexistence. The chaos indicator DLI has been used for clarity in detection of regular and chaotic motion. Finally,the correlation dimension for the chaotic set has also been calculated for certain set of parameter values

    Synthesis, structure and molecular Hirshfeld surface analysis of polymeric cadmium(II) complex involving tetradentate N3S-donor ligand and dicyanamide as bridging ligand

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    663-668One new polymeric cadmium(II) complex {[Cd(bdmpe)(µ1,5-dca)]ClO4.CH3OH}n has been synthesized by the reaction of cadmium perchlorate with ligand N,N-bis((3,5-dimethyl-1H-pyrazol-1-yl)methyl)-2-(phenylthio)ethan-1-amine (bdmpe) in presence of dca (dicyanamide, N(CN)2-) as bridging ligand in methanol and characterized by spectroscopic techniques. Single crystal X-ray diffraction study of the complex confirmed that it has polymeric 1D chain and each cadmium centre has distorted octahedral geometry with N5S coordination and is bonded through two terminal nitrile group of the dca ligand using m1,5 coordination modes. Intermolecular interactions and packing modes of the compound are described by Hirshfeld surface analysis and two dimensional finger print plots

    Synthesis, structure and molecular Hirshfeld surface analysis of polymeric cadmium(II) complex involving tetradentate N3S-donor ligand and dicyanamide as bridging ligand

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    One new polymeric cadmium(II) complex {[Cd(bdmpe)(µ1,5-dca)]ClO4.CH3OH}n has been synthesized by the reaction of cadmium perchlorate with ligand N,N-bis((3,5-dimethyl-1H-pyrazol-1-yl)methyl)-2- phenylthio)ethan-1-amine (bdmpe) in presence of dca (dicyanamide, N(CN)2-) as bridging ligand in methanol and characterized by spectroscopic techniques. Single crystal X-ray diffraction study of the complex confirmed that it has polymeric 1D chain and each cadmium centre has distorted octahedral geometry with N5S coordination and is bonded through two terminal nitrile group of the dca ligand using m1,5 coordination modes. Intermolecular interactions and packing modes of the compound are described by Hirshfeld surface analysis and two dimensional finger print plots

    Comparison of LDL fatty acid and carotenoid concentrations and oxidative resistance of LDL in volunteers from countries with different rates of cardiovascular disease

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    Within Europe there are differences in cardiovascular disease (CVD) risk between countries and this might be related to dietary habits. Oxidative modification of LDL is suggested to increase the risk of CVD and both the fatty acid and antioxidant content of LDL can affect its oxidation. In the present study, concentration of LDL fatty acid and antioxidant micronutrients (tocopherols and carotenoids) and ex vivo oxidative resistance of LDL (lag phase) was compared in volunteers from five countries with different fruit and vegetable intakes and reported rates of CVD. Eighty volunteers (forty males, forty females per centre), age range 25-45 years, were recruited from France, Northern Ireland, UK, Republic of Ireland, The Netherlands, and Spain, and their LDL composition and lag phase were measured. There were some differences in LDL carotenoid and α-tocopherol concentrations between countries. α-Tocopherol was low and β- + γ-tocopherol were high (P<0·001) in the Dutch subjects. β-Carotene concentrations were significantly different between the French and Spanish volunteers, with French showing the highest and Spanish the lowest concentration. LDL lycopene was not different between centres in contrast to lutein, which was highest in French (twofold that in the Dutch and Spanish and threefold that in Northern Ireland and the Republic of Ireland, P<0·001). However absolute LDL saturated, monounsaturated, polyunsaturated and total unsaturated fatty acid concentrations were different between countries (P<0·001, total unsaturated highest in Northern Ireland) there was little difference in unsaturated:saturated fatty acid concentration ratios and no difference in polyunsaturated:saturated fatty acid concentration ratios. LDL from the Republic of Ireland (a region with a high rate of CVD) had greater resistance to Cu-stimulated oxidation than samples obtained from volunteers in other countries. In conclusion, LDL composition did not predict resistance to Cu-stimulated oxidation, nor is there evidence that LDL from volunteers in countries with lower rates of CVD have greater resistance to oxidatio

    The prevalence of and factors associated with prior induced abortion among women who gave birth in Victoria, 2010-2019

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    OBJECTIVE: To assess the prevalence of a history of induced abortion among women who gave birth in Victoria during 2010-2019; to assess the association of socio-demographic factors with a history of induced abortion. STUDY DESIGN: Retrospective cohort study; analysis of cross-sectional perinatal data in the Victorian Perinatal Data Collection (VPDC). SETTING, PARTICIPANTS: All women who gave birth (live or stillborn) in Victoria, 1 January 2010 - 31 December 2019. MAIN OUTCOME MEASURES: Self-reported induced abortions prior to the index birth; outcome of the most recent pregnancy preceding the index pregnancy. RESULTS: Of the 766 488 women who gave birth during 2010-2019, 93 251 reported induced abortions (12.2%), including 36 938 of 338 547 nulliparous women (10.9%). Women living in inner regional (adjusted odds ratio [aOR], 0.94; 95% confidence interval [CI], 0.93-0.96) or outer regional/remote/very remote areas (aOR, 0.86; 95% CI, 0.83-0.89) were less likely than women in major cities to report induced abortions. The likelihood increased steadily with age at the index birth and with parity, and was also higher for women without partners at the index birth (aOR, 2.20; 95% CI, 2.16-2.25) and Aboriginal and Torres Strait Islander women (aOR, 1.32; 95% CI, 1.25-1.40). The likelihood was lower for women born in most areas outside Australia than for those born in Australia. The likelihood of a history of induced abortion declined across the study period overall (2019 v 2010: 0.93; 95% CI, 0.90-0.96) and for women in major cities (0.88; 95% CI, 0.84-0.91); rises in inner regional and outer regional/remote/very remote areas were not statistically significant. CONCLUSIONS: Access to abortion care in Victoria improved during 2010-2019, but the complex interplay between contraceptive use, unintended pregnancy, and induced abortion requires further exploration by remoteness of residence. Robust information about numbers of unintended pregnancies and access to reproductive health services are needed to guide national sexual and reproductive health policy and practice

    Dementia with Lewy bodies research consortia: A global perspective from the ISTAART Lewy Body Dementias Professional Interest Area working group

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    Dementia with Lewy bodies (DLB) research has seen a significant growth in international collaboration over the last three decades. However, researchers face a challenge in identifying large and diverse samples capable of powering longitudinal studies and clinical trials. The DLB research community has begun to focus efforts on supporting the development and harmonization of consortia, while also continuing to forge networks within which data and findings can be shared. This article describes the current state of DLB research collaborations on each continent. We discuss several established DLB cohorts, many of whom have adopted a common framework, and identify emerging collaborative initiatives that hold the potential to expand DLB networks and diversify research cohorts. Our findings identify geographical areas into which the global DLB networks should seek to expand, and we propose strategies, such as the creation of data-sharing platforms and the harmonization of protocols, which may further potentiate international collaboration.publishedVersio
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