| Description: | Department of Chemical Oceanography,Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/2377 |
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| Dyuthi-T0649.pdf | (16.69Mb) |
| Abstract: | The term reliability of an equipment or device is often meant to indicate the probability that it carries out the functions expected of it adequately or without failure and within specified performance limits at a given age for a desired mission time when put to use under the designated application and operating environmental stress. A broad classification of the approaches employed in relation to reliability studies can be made as probabilistic and deterministic, where the main interest in the former is to device tools and methods to identify the random mechanism governing the failure process through a proper statistical frame work, while the latter addresses the question of finding the causes of failure and steps to reduce individual failures thereby enhancing reliability. In the probabilistic attitude to which the present study subscribes to, the concept of life distribution, a mathematical idealisation that describes the failure times, is fundamental and a basic question a reliability analyst has to settle is the form of the life distribution. It is for no other reason that a major share of the literature on the mathematical theory of reliability is focussed on methods of arriving at reasonable models of failure times and in showing the failure patterns that induce such models. The application of the methodology of life time distributions is not confined to the assesment of endurance of equipments and systems only, but ranges over a wide variety of scientific investigations where the word life time may not refer to the length of life in the literal sense, but can be concieved in its most general form as a non-negative random variable. Thus the tools developed in connection with modelling life time data have found applications in other areas of research such as actuarial science, engineering, biomedical sciences, economics, extreme value theory etc. |
| Description: | Division of Statistics, School of Mathematical Sciences, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3696 |
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| Dyuthi-T1661.pdf | (1.439Mb) |
| Abstract: | It is highly desirable that any multivariate distribution possessescharacteristic properties that are generalisation in some sense of the corresponding results in the univariate case. Therefore it is of interest to examine whether a multivariate distribution can admit such characterizations. In the exponential context, the question to be answered is, in what meaning— ful way can one extend the unique properties in the univariate case in a bivariate set up? Since the lack of memory property is the best studied and most useful property of the exponential law, our first endeavour in the present thesis, is to suitably extend this property and its equivalent forms so as to characterize the Gumbel's bivariate exponential distribution. Though there are many forms of bivariate exponential distributions, a matching interest has not been shown in developing corresponding discrete versions in the form of bivariate geometric distributions. Accordingly, attempt is also made to introduce the geometric version of the Gumbel distribution and examine several of its characteristic properties. A major area where exponential models are successfully applied being reliability theory, we also look into the role of these bivariate laws in that context. The present thesis is organised into five Chapters |
| Description: | Department of Mathematics and Statistics, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3657 |
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| Dyuthi-T1577.pdf | (3.283Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/1679 |
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| Dyuthi-T0153.pdf | (4.461Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/1676 |
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| Dyuthi-T0152.pdf | (4.552Mb) |
| Abstract: | Two graphs G and H are Turker equivalent if they have the same set of Turker angles. In this paper some Turker equivalent family of graphs are obtained. |
| URI: | http://dyuthi.cusat.ac.in/purl/643 |
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| Turker equivale ... for graph theory notes.pdf | (161.4Kb) |
| Abstract: | This thesis entitled Reliability Modelling and Analysis in Discrete time Some Concepts and Models Useful in the Analysis of discrete life time data.The present study consists of five chapters. In Chapter II we take up the derivation of some general results useful in reliability modelling that involves two component mixtures. Expression for the failure rate, mean residual life and second moment of residual life of the mixture distributions in terms of the corresponding quantities in the component distributions are investigated. Some applications of these results are also pointed out. The role of the geometric,Waring and negative hypergeometric distributions as models of life lengths in the discrete time domain has been discussed already. While describing various reliability characteristics, it was found that they can be often considered as a class. The applicability of these models in single populations naturally extends to the case of populations composed of sub-populations making mixtures of these distributions worth investigating. Accordingly the general properties, various reliability characteristics and characterizations of these models are discussed in chapter III. Inference of parameters in mixture distribution is usually a difficult problem because the mass function of the mixture is a linear function of the component masses that makes manipulation of the likelihood equations, leastsquare function etc and the resulting computations.very difficult. We show that one of our characterizations help in inferring the parameters of the geometric mixture without involving computational hazards. As mentioned in the review of results in the previous sections, partial moments were not studied extensively in literature especially in the case of discrete distributions. Chapters IV and V deal with descending and ascending partial factorial moments. Apart from studying their properties, we prove characterizations of distributions by functional forms of partial moments and establish recurrence relations between successive moments for some well known families. It is further demonstrated that partial moments are equally efficient and convenient compared to many of the conventional tools to resolve practical problems in reliability modelling and analysis. The study concludes by indicating some new problems that surfaced during the course of the present investigation which could be the subject for a future work in this area. |
| Description: | Department of Statistics, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3095 |
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| Dyuthi-T1069.pdf | (2.275Mb) |
| Abstract: | This thesis contains a study of conservation laws of fluid mechanics. These conservation laws though classical, have been put to extensive studies in t:he past many decades |
| Description: | Department of Mathematics And Statistics, Cochin University of Science And Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3825 |
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| Dyuthi-T1756.pdf | (1.956Mb) |
| Abstract: | In this paper, we study some dynamic generalized information measures between a true distribution and an observed (weighted) distribution, useful in life length studies. Further, some bounds and inequalities related to these measures are also studied |
| Description: | Statistica,VOL 68(1),pp 71-84 |
| URI: | http://dyuthi.cusat.ac.in/purl/4275 |
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| Some Dynamic Ge ... ext Of Weighted Models.pdf | (350.4Kb) |
| Abstract: | The thesis introduced the octree and addressed the complete nature of problems encountered, while building and imaging system based on octrees. An efficient Bottom-up recursive algorithm and its iterative counterpart for the raster to octree conversion of CAT scan slices, to improve the speed of generating the octree from the slices, the possibility of utilizing the inherent parallesism in the conversion programme is explored in this thesis. The octree node, which stores the volume information in cube often stores the average density information could lead to “patchy”distribution of density during the image reconstruction. In an attempt to alleviate this problem and explored the possibility of using VQ to represent the imformation contained within a cube. Considering the ease of accommodating the process of compressing the information during the generation of octrees from CAT scan slices, proposed use of wavelet transforms to generate the compressed information in a cube. The modified algorithm for generating octrees from the slices is shown to accommodate the eavelet compression easily. Rendering the stored information in the form of octree is a complex task, necessarily because of the requirement to display the volumetric information. The reys traced from each cube in the octree, sum up the density en-route, accounting for the opacities and transparencies produced due to variations in density. |
| URI: | http://dyuthi.cusat.ac.in/purl/977 |
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| Dyuthi-T0151.pdf | (4.667Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/5246 |
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| Dyuthi T-2282.pdf | (1.927Mb) |
| Abstract: | The main purpose of the study is to extent concept of the class of spaces called ‘generalized metric spaces’ to fuzzy context and investigates its properties. Any class of spaces defined by a property possessed by all metric spaces could technically be called as a class of ‘generalized metric spaces’. But the term is meant for classes, which are ‘close’ to metrizable spaces in some under certain kinds of mappings. The theory of generalized metric spaces is closely related to ‘metrization theory’. The class of spaces likes Morita’s M- spaces, Borges’s w-spaces, Arhangelskii’s p-spaces, Okuyama’s spaces have major roles in the theory of generalized metric spaces. The thesis introduces fuzzy metrizable spaces, fuzzy submetrizable spaces and proves some characterizations of fuzzy submetrizable spaces, and also the fuzzy generalized metric spaces like fuzzy w-spaces, fuzzy Moore spaces, fuzzy M-spaces, fuzzy k-spaces, fuzzy -spaces study of their properties, prove some equivalent conditions for fuzzy p-spaces. The concept of a network is one of the most useful tools in the theory of generalized metric spaces. The -spaces is a class of generalized metric spaces having a network. |
| URI: | http://dyuthi.cusat.ac.in/purl/46 |
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| Dyuthi-T0120.pdf | (2.493Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/1239 |
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| Vincy Samuel 1989.PDF | (316.4Kb) |
| Abstract: | Mackerel fishery at many places in the country including Cochin as well as at all—India level, besides its seasonal changes to have long-term flucations apparently evincing a ten-year cycle. Published literature on the fishery and biology of mackerel at many places are available. But attempts on population studies and assessment of stock are scanty. The researchers attention at this juncture turned to investigations on population dynamics of the mackerel .On account of the long-term Fluctuations in the fishery, it was felt desirable to have data For a number of years together to facilitate adequate coverage of a unit of time in the 10-year cycle. Investigations on length weight relationships for 16 seasons were hence carried out. This thesis is written eection'by section embodying‘ the results and_findings of the work carried out under different subject areas. It contains sections on identity of the species, information on its spatial and temporal distribution along the Indian coast, study on length-weight relationships, growth and age determination, population studies and stock assessment, and discussions.This dissertation is the outcome of the works of the candidate on the Indian mackerel. The work, however is based on exploited resource of the inshore waters. In the course of this analysis, lacunae existing in the investigations on the Indian mackerel are therefore identified and presented For future work |
| Description: | Central Marine Fisheries Research Institute |
| URI: | http://dyuthi.cusat.ac.in/purl/3274 |
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| Dyuthi-T1248.pdf | (5.744Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/1190 |
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| Noble A 1987.PDF | (263.3Kb) |
| Abstract: | It is believed that every fuzzy generalization should be formulated in such a way that it contain the ordinary set theoretic notion as a special case. Therefore the definition of fuzzy topology in the line of C.L.CHANG E9] with an arbitrary complete and distributive lattice as the membership set is taken. Almost all the results proved and presented in this thesis can, in a sense, be called generalizations of corresponding results in ordinary set theory and set topology. However the tools and the methods have to be in many of the cases, new. Here an attempt is made to solve the problem of complementation in the lattice of fuzzy topologies on a set. It is proved that in general, the lattice of fuzzy topologies is not complemented. Complements of some fuzzy topologies are found out. It is observed that (L,X) is not uniquely complemented. However, a complete analysis of the problem of complementation in the lattice of fuzzy topologies is yet to be found out |
| Description: | Depantment of Mathematics and Statistics Cochin University of Scince and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3440 |
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| Dyuthi-T1417.pdf | (1.609Mb) |
| Abstract: | The eigenvalue of a graph is the eigenvalue of its adjacency matrix . A graph G is integral if all of its cigenvalues are integers. In this paper some new classes of integral graphs are constructed. |
| URI: | http://dyuthi.cusat.ac.in/purl/1535 |
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| Some new integral graphs.PDF | (3.692Mb) |
| Abstract: | An immense variety of problems in theoretical physics are of the non-linear type. Non~linear partial differential equations (NPDE) have almost become the rule rather than an exception in diverse branches of physics such as fluid mechanics, field theory, particle physics, statistical physics and optics, and the construction of exact solutions of these equations constitutes one of the most vigorous activities in theoretical physics today. The thesis entitled ‘Some Non-linear Problems in Theoretical Physics’ addresses various aspects of this problem at the classical level. For obtaining exact solutions we have used mathematical tools like the bilinear operator method, base equation technique and similarity method with emphasis on its group theoretical aspects. The thesis deals with certain methods of finding exact solutions of a number of non-linear partial differential equations of importance to theoretical physics. Some of these new solutions are of relevance from the applications point of view in diverse branches such as elementary particle physics, field theory, solid state physics and non-linear optics and give some insight into the stable or unstable behavior of dynamical Systems The thesis consists of six chapters. |
| Description: | Department of Physics, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3303 |
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| Dyuthi-T1270.pdf | (4.265Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/1105 |
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| Baby B V 1985.pdf | (1.825Mb) |
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