Abstract: | In this thesis, the concept of reversed lack of memory property and its generalizations is studied.We we generalize this property which involves operations different than the ”addition”. In particular an associative, binary operator ” * ” is considered. The univariate reversed lack of memory property is generalized using the binary operator and a class of probability distributions which include Type 3 extreme value, power function, reflected Weibull and negative Pareto distributions are characterized (Asha and Rejeesh (2009)). We also define the almost reversed lack of memory property and considered the distributions with reversed periodic hazard rate under the binary operation. Further, we give a bivariate extension of the generalized reversed lack of memory property and characterize a class of bivariate distributions which include the characterized extension (CE) model of Roy (2002a) apart from the bivariate reflected Weibull and power function distributions. We proved the equality of local proportionality of the reversed hazard rate and generalized reversed lack of memory property. Study of uncertainty is a subject of interest common to reliability, survival analysis, actuary, economics, business and many other fields. However, in many realistic situations, uncertainty is not necessarily related to the future but can also refer to the past. Recently, Di Crescenzo and Longobardi (2009) introduced a new measure of information called dynamic cumulative entropy. Dynamic cumulative entropy is suitable to measure information when uncertainty is related to the past, a dual concept of the cumulative residual entropy which relates to uncertainty of the future lifetime of a system. We redefine this measure in the whole real line and study its properties. We also discuss the implications of generalized reversed lack of memory property on dynamic cumulative entropy and past entropy.In this study, we extend the idea of reversed lack of memory property to the discrete set up. Here we investigate the discrete class of distributions characterized by the discrete reversed lack of memory property. The concept is extended to the bivariate case and bivariate distributions characterized by this property are also presented. The implication of this property on discrete reversed hazard rate, mean past life, and discrete past entropy are also investigated. |
Description: | Department of Statistics, Cochin University of Science and Technology |
URI: | http://dyuthi.cusat.ac.in/purl/2356 |
Files | Size |
---|---|
Dyuthi-T0629.pdf | (629.2Kb) |
URI: | http://dyuthi.cusat.ac.in/purl/5285 |
Files | Size |
---|---|
Dyuthi T-2321.pdf | (7.323Mb) |
Abstract: | The understanding of the theory of entrepreneurship depends upon one set of definitions which provide the base for analytical study. The main objective of the study was to understand the distribution of entrepreneurship in the manufacturing sector among different categories of people in kerala and to differentiate the socio - psychological background of successful entrepreneur- managers from unsuccessful entrepreneur-managers. The purpose of the study, a sample of 150 entrepreneur-managers of SS1 units spread over Ernakulam district was surveyed through a specially designed questionnaire. |
Description: | School of Management Studies, Cochin University of Science and Technology |
URI: | http://dyuthi.cusat.ac.in/purl/3506 |
Files | Size |
---|---|
Dyuthi-T1456.pdf | (4.323Mb) |
Abstract: | This doctoral thesis addresses the growing concern about the significant changes in the climatic and weather patterns due to the aerosol loading that have taken place in the Indo Gangetic Plain(IGP)which includes most of the Northern Indian region. The study region comprises of major industrial cities in India (New Delhi, Kanpur, Allahabad, Jamshedpur and Kolkata). Northern and central parts of India are one of the most thickly populated areas in the world and have the most intensely farmed areas. Rapid increase in population and urbanization has resulted in an abrupt increase in aerosol concentrations in recent years. The IGP has a major source of coal; therefore most of the industries including numerous thermal power plants that run on coal are located around this region. They inject copious amount of aerosols into the atmosphere. Moreover, the transport of dust aerosols from arid locations is prevalent during the dry months which increase the aerosol loading in theatmosphere. The topography of the place is also ideal for the congregation of aerosols. It is bounded by the Himalayas in the north, Thar Desert in the west, the Vindhyan range in the south and Brahmaputra ridge in the east. During the non‐monsoon months (October to May) the weather in the location is dry with very little rainfall. Surface winds are weak during most of the time in this dry season. The aerosols that reach the location by means of long distance transport and from regional sources get accumulated under these favourable conditions. The increase in aerosol concentration due to the complex combination of aerosol transport and anthropogenic factors mixed with the contribution from the natural sources alters the optical properties and the life time of clouds in the region. The associated perturbations in radiative balance have a significant impact on the meteorological parameters and this in turn determines the precipitation forming process. Therefore, any change in weather which disturbs the normal hydrological pattern is alarming in the socio‐economic point of view. Hence, the main focus of this work is to determine the variation in transport and distribution of aerosols in the region and to understand the interaction of these aerosols with meteorological parameters and cloud properties. |
Description: | Department of Atmospheric Sciences, Cochin University of Science and Technology |
URI: | http://dyuthi.cusat.ac.in/purl/2764 |
Files | Size |
---|---|
Dyuthi-T0787.pdf | (6.630Mb) |
Abstract: | Mechanical properties and thermal degradation of natural rubber compounds containing castor oil were studied to evaluate its suitability as plasticizer. Naphthenic oil was used as a reference plasticizer. The cure time was marginally lower in the case of castor oil mixes, probably due to the presence offree fatty acids in it. The tear strength and modulus were better in the case of mixes containing castor oil, while most of the other mechanical properties were comparable to the mixes containing naphthenic oil. The heat build up and compression set were higher than that of the naphthenic oil mixes. Thermal studies showed an increase of 8 °C in the temperature of initiation of degradation and an increase of 6 °C in the temperature at which the peak rate of degradation occurred. The peak rate of degradation was comparable to that of the reference compound |
URI: | http://dyuthi.cusat.ac.in/purl/890 |
Files | Size |
---|---|
RAJU,P, NANDANA ... THE USE OF CASTOR OIL.PDF | (7.035Mb) |
Abstract: | Mechanical properties and thermal degradation characteristics of natural rubber compounds captaining coconut oil were compared with that of a control compound containing naphthenic oil. Cure time was marginally lower in the case of coconut oil mixes, probably due to the presence of free fatty acids. Tensile strength , tear strength, resilience and abrasion resistance were better than the naphthenic oil-based compounds . Compression set and hardness were marginally inferior The coconut oil mixes had a crosslink density comparable to that of the reference compound. Thermal studies showed that the temperature of initiation of degradation was increased by 10°C and the temperature at which the peak rate of degradation occured was increased by 7°C. The peak rate of degradation was compa rable to the control compound. |
URI: | http://dyuthi.cusat.ac.in/purl/891 |
Files | Size |
---|---|
RAJU,P, NANDANA ... OIL AS PLASTICISERPDF.PDF | (4.469Mb) |
Abstract: | At this era of energy crisis and resource depletion, availability of conventional materials throughout the year in quantity and quality, pose a hectic problem for the builders. Adding fuel to the fire, the demand of these materials increases day by day, since the housing and habitat requirements exponentially increase time to time. There is an international concern over this crisis and researchers are reorienting themselves, so as to evolve appropriate masonry units, using locally available cheap materials and technology. The concept of green material and construction has been well conceived in the research so that marginal materials and unskilled labour can be employed for the mass production of building blocks. In this context, considering earth as a sustainable material, there is a growing interest in the use of it, as a modern construction material. Solid waste management is one of the current major environmental concerns in our country. Our country is left with millions of cubic metre of waste plastics. One of the methods to satisfactorily address this solid waste management and the environmental issues is to suitably accommodate the waste in some form (as fibres). Their employability in block making in the form of fibres (plastic fibre- mud blocks) can be investigated through a fundamental research. Also, the review of the existing literature shows that most studies on natural fibres are focussed on cellulose based/ vegetable fibres obtained from renewable plant resources except in very few cases, where animal fibre, plastic fibre and polystyrene fabric were used. At this context, for the plastic fibre-mud blocks to be more widely applicable, a systematic quantification of the relevant physical and mechanical properties of the fibre masonry units is crucial, to enable an objective evaluation of the composite material’s response to actual field condition. This research highlights the salient observations from the detailed investigation of a systematic study on the effect of embedded fibres, made of plastic wastes on the performance of stabilised mud blocks. |
Description: | School of Engineering, Cochin University of Science and Technology |
URI: | http://dyuthi.cusat.ac.in/purl/3974 |
Files | Size |
---|---|
Dyuthi-T1796.pdf | (2.541Mb) |
Abstract: | Soil moisture plays a cardinal role in sustaining eclological balance and agricultural development – virtually the very existence of life on earth. Because of the growing shortage of water resources, we have to use the available water most efficiently by proper management. Better utilization of rainfall or irrigation management depends largely on the water retention characteristics of the soil.Soil water retention is essential to life and it provides an ongoing supply of water to plants between periods of irrigation so as to allow their continued growth and survival.It is essential to maintain readily available water in the soil if crops are to sustain satisfactory growth. The plant growth may be retarded if the soil moisture is either deficient or excessive. The optimum moisture content is that moisture which leads to optimum growth of plant. When watering is done, the amount of water supplied should be such that the water content is equal to the field capacity that is the water remained in the saturated soil after gravitational drainage. Water will gradually be utilized consumptively by plants after the water application, and the soil moisture will start falling. When the water content in the soil reaches the value known as permanent wilting point (when the plant starts wilting) fresh dose of irrigation may be done so that water content is again raised to the field capacity of soil.Soil differ themselves in some or all the properties depending on the difference in the geotechnical and environmental factors. Soils serve as a reservoir of the nutrients and water required for crops.Study of soil and its water holding capacity is essential for the efficient utilization of irrigation water. Hence the identification of the geotechnical parameters which influence the water retention capacity, chemical properties which influence the nutrients and the method to improve these properties have vital importance in irrigation / agricultural engineering. An attempt in this direction has been made in this study by conducting the required tests on different types of soil samples collected from various locations in Trivandrum district Kerala, with and without admixtures like coir pith, coir pith compost and vermi compost. Evaluation of the results are presented and a design procedure has been proposed for a better irrigation scheduling and management. |
Description: | Division of Civil Engineering, Cochin University of Science and Technology |
URI: | http://dyuthi.cusat.ac.in/purl/2361 |
Files | Size |
---|---|
Dyuthi-T0633.pdf | (5.314Mb) |
Description: | Department of Physics, Cochin University of Science and Technology |
URI: | http://dyuthi.cusat.ac.in/xmlui/purl/1960 |
Files | Size |
---|---|
Dyuthi-T0481.pdf | (7.945Mb) |
Abstract: | The thesis is divided into nine chapters including introduction. Mainly we determine ultra L-topologies in the lattice of L- topologies and study their properties. We nd some sublattices in the lattice of L-topologies and study their properties. Also we study the lattice structure of the set of all L-closure operators on a set X. |
Description: | Department of Mathematics Cochin University of Science and Technology |
URI: | http://dyuthi.cusat.ac.in/purl/3897 |
Files | Size |
---|---|
Dyuthi-T1787.pdf | (838.2Kb) |
URI: | http://dyuthi.cusat.ac.in/purl/5174 |
Files | Size |
---|---|
Dyuthi- T2209.pdf | (13.21Mb) |
Description: | Department of Applied Economics, Cochin University of Science and Technology |
URI: | http://dyuthi.cusat.ac.in/purl/2958 |
Files | Size |
---|---|
Dyuthi-T0949.pdf | (4.032Mb) |
Abstract: | In this thesis an attempt is made to study vortex knots based on the work of Keener . It is seen that certain mistakes have been crept in to the details of this paper. We have chosen this study for an investigation as it is the first attempt to study vortex knots. Other works had given attention to this. In chapter 2 we have considered these corrections in detail. In chapter 3 we have tried a simple extension by introducing vorticity in the evolution of vortex knots. In chapter 4 we have introduced a stress tensor related to vorticity. Chapter 5 is the general conclusion.Knot theory is a branch of topology and has been developed as an independent branch of study. It has wide applications and vortex knot is one of them. As pointed out earlier, most of the studies in fluid dynamics exploits the analogy between vorticity and magnetic induction in the case of MHD. But vorticity is more general than magnetic induction and so it is essential to discuss the special properties of vortex knots, independent of MHD flows. This is what is being done in this thesis. |
Description: | Dept.of Mathematics, Cochin University of Science and Technology |
URI: | http://dyuthi.cusat.ac.in/purl/2749 |
Files | Size |
---|---|
Dyuthi-T0774.pdf | (2.192Mb) |
Abstract: | HINDI |
Description: | Department of Hindi, Cochin University of Science and Technology |
URI: | http://dyuthi.cusat.ac.in/purl/4842 |
Files | Size |
---|---|
Dyuthi-T1939.pdf | (9.771Mb) |
Abstract: | Cure characteristics and mechanical properties of styrene butadiene rubber reclaimed rubber blends were studied. The blends showed improved processability, as indicated by the minimum torque values. Cure characteristics like minimum torque, (maximum-minimum) torque, cure time and cure rate decreased in the presence of reclaimed rubber. Tensile strength, tear strength, elongation at break were higher for blends. Resilience decreased with reclaim content. Compression set and abrasion loss were higher in the blends. |
URI: | http://dyuthi.cusat.ac.in/purl/900 |
Files | Size |
---|---|
sreeja t d, S. ... dine rubber............PDF | (3.471Mb) |
Abstract: | This paper proposes a content based image retrieval (CBIR) system using the local colour and texture features of selected image sub-blocks and global colour and shape features of the image. The image sub-blocks are roughly identified by segmenting the image into partitions of different configuration, finding the edge density in each partition using edge thresholding, morphological dilation. The colour and texture features of the identified regions are computed from the histograms of the quantized HSV colour space and Gray Level Co- occurrence Matrix (GLCM) respectively. A combined colour and texture feature vector is computed for each region. The shape features are computed from the Edge Histogram Descriptor (EHD). A modified Integrated Region Matching (IRM) algorithm is used for finding the minimum distance between the sub-blocks of the query and target image. Experimental results show that the proposed method provides better retrieving result than retrieval using some of the existing methods |
Description: | International Journal of Computer Science Issues (IJCSI) |
URI: | http://dyuthi.cusat.ac.in/purl/3887 |
Files | Size |
---|---|
A Sub-block Bas ... grated Region Matching.pdf | (443.6Kb) |
Abstract: | We report the experimental observation of subcritical Hopf bifurcation and the existence of non-oscillating “windows” in the dynamics of a Ne-Nd hollow cathode discharge current as the control parameter. |
URI: | http://dyuthi.cusat.ac.in/purl/2581 |
Files | Size |
---|---|
Dyuthi-P0141.pdf | (265.0Kb) |
Abstract: | HINDI |
Description: | DEPARTMENT OF HINDI Cochin University of Science and Technology |
URI: | http://dyuthi.cusat.ac.in/purl/4755 |
Files | Size |
---|---|
Dyuthi-T1852.pdf | (7.236Mb) |
Abstract: | The present scientific investigation of the effects of copper, mercury and cadmium has focussed on their effects on two commercially important marine bivalve species, Perna indica (brown mussel) and Donax incarnatus (wedge clam), conspicuous representatives of the tropical intertidal areas. The investigation centred around delineating the cause and effects of heavy metal stress, individually and in combination on these species under laboratory conditions. A clear understanding of the cause and effect can be had only if laboratory experiments are conducted employing sub-lethal concentrations of the above toxicants. Therefore, during the course of the investigation, sub-lethal concentrations of copper, mercury and cadmium were employed to assess the concentration dependent effects on survival, ventilation rate, O:N ratio and tissues. The results obtained are compared with the already available information and partitioned in sections to make a meaningful presentation.The thesis is presented in five chapters comprising INTRODUCTION, ACUTE TOXICITY, VENTILATION RATE, OXYGEN : NITROGEN RATIO and HISTOPATHOLOGY. Each chapter has been divided into various sections such as INTRODUCTION, REVIEW OF LITERATURE, MATERIAL AND METHODS, RESULTS and DISCUSSION |
Description: | Head, Division of Marine Biology, Microbiology and Biochemistry, School of Marine Sciences, Cochin University of Science and Technology |
URI: | http://dyuthi.cusat.ac.in/purl/3222 |
Files | Size |
---|---|
Dyuthi-T1196.pdf | (4.457Mb) |
URI: | http://dyuthi.cusat.ac.in/purl/5575 |
Files | Size |
---|---|
Dyuthi T-2615.pdf | (31.69Mb) |
Dyuthi Digital Repository Copyright © 2007-2011 Cochin University of Science and Technology. Items in Dyuthi are protected by copyright, with all rights reserved, unless otherwise indicated.