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2017 - 201912020 - 20231
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    ThesisItemOpen Access
    Bayesian Estimation for Some Lifetime Models under Different Loss Functions
    (Chaudhary Charan Singh Haryana Agricultural University hisar, 2023-01) Pavitra Kumari; Vinay Kumar
    The life testing experiments are carried out to obtain the lifetime data on patients for survival analysis and to study the reliability of electrical, electronic and mechanical systems, information theory, artificial intelligence, etc. This thesis deals with the classical and Bayesian estimation methods for the generalized of lifetime models. We consider four distinct loss functions, namely, square error loss function, entropy loss function, precautionary loss function, Linex loss function and type II censoring in this thesis. Type II censoring has the significant advantage that you know in advance how many failure times your test will yield. Generalizations of univariate lifetime distributions are often of interest to serve for real life phenomena. These generalized lifetime distributions are very useful in many fields such as medicine, physics, engineering and biology. We consider three distinct lifetime models, namely, Lomax, Rayleigh Lomax and IPBH lifetime model and developed statistical inferences for the associated model parameters and reliability characteristics from both the classical and Bayesian estimation perspectives in Chapter 4. Lomax distribution is one of the well-known univariate distributions that is considered as an alternative to the exponential, gamma and Weibull distributions for heavy tailed data. In this thesis, we introduce a generalization of the Lomax distribution called Rayleigh Lomax (RL) distribution. This distribution provides great fit in modelling wide range of real data sets. It is a very flexible distribution that is related to some of the useful univariate distributions such as exponential, Weibull and Rayleigh distributions. Moreover, this distribution can also be transformed to a lifetime distribution which is applicable in many situations. For example, we obtain the inverse estimation and confidence intervals. In present study apply AIC and BIC to detect the changes in parameters of the RL distribution. The performance of these approaches is studied through simulations and applications to real data sets. The statistical software R is used for computation throughout the thesis. Finally, a complete list of references and other literature surveys are given at the end of the thesis as a bibliography.
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    ThesisItemOpen Access
    Survival and management of Colletotrichum gloeosporioides (Penz. & Sacc.) causing mango anthracnose (Mangifera indica L.)
    (CCSHAU, 2017) Pavitra Kumari; Rajender Singh
    Mango anthracnose caused by Colletotrichum gloeosporioides (Penz. & Sacc.) is a very serious fungal disease and causes substantial yield losses in mango cultivars. The present investigations were carried out on survival and viability of C. gloeosporioides fungus, evaluation of different inoculation methods for disease development and evaluation of fungicides and botanicals for their efficacy. The efficacy of urea was tested under in vitro conditions; urea was found effective in inhibition of mycelial growth up to 72.8 per cent at 5% concentration. The pathogen survived for seven month in soil as conidia or mycelium in infected debris under adverse conditions. As the depth and duration increased, there has been a decrease in viability of the fungus indicating its long survival on the soil surface only. The fungus could not survive at 5 cm depth after seven months of burial in comparison to 81.6 per cent survival at same depth after one month of burial. At 5 cm and 10 cm depth conidia or mycelium remained viable for five months at 2% urea concentration, however, fungus remained viable up to four months at 5% urea concentrations. The fungus invaded the host tissues through the injured as well as intact surface of leaves and fruits showing clearly its pathogenic ability. The disease symptoms appeared on mango leaves and fruits after 36 hours of pin prick inoculation method at 25±1˚ C. Out of five fungicides tested in vitro, carbendazim completely inhibited mycelial growth up to 100% at 100 ppm concentration. Propiconazole at 500 ppm, while mancozeb at 1000 ppm concentration inhibited mycelial growth up to 100%. Among botanicals eucalyptus leaf extract was found most effective in inhibition of mycelial growth up to 70.4 per cent at 10 per cent concentration. Under field conditions, two foliar spray with carbendazim @ 0.1% at 15 and 30 days after inoculation disease was found most effective in controlling disease up to 71.43% and 65.22 per cent in cv. Langra and Dashehari, respectively. Two foliar sprays with eucalyptus leaf extract @ 10% at 15 and 30 days after inoculation was also found effective in reducing the disease severity over untreated control.