Analysis of Some Stochastic Inventory Models with Pooling Retrial of Customers

The thesis deals with analysis of some Stochastic Inventory Models with Pooling/Retrial of Customers.. In the first model we analyze an (s,S) production Inventory system with retrial of customers. Arrival of customers from outside the system form a Poisson process. The inter production times are exponentially distributed with parameter µ. When inventory level reaches zero further arriving demands are sent to the orbit which has capacity M(<∞). Customers, who find the orbit full and inventory level at zero are lost to the system. Demands arising from the orbital customers are exponentially distributed with parameter γ. In the model-II we extend these results to perishable inventory system assuming that the life-time of each item follows exponential with parameter θ. The study deals with an (s,S) production inventory with service times and retrial of unsatisfied customers. Primary demands occur according to a Markovian Arrival Process(MAP). Consider an (s,S)-retrial inventory with service time in which primary demands occur according to a Batch Markovian Arrival Process (BMAP). The inventory is controlled by the (s,S) policy and (s,S) inventory system with service time. Primary demands occur according to Poissson process with parameter λ. The study concentrates two models. In the first model we analyze an (s,S) Inventory system with postponed demands where arrivals of demands form a Poisson process. In the second model, we extend our results to perishable inventory system assuming that the life-time of each item follows exponential distribution with parameter θ. Also it is assumed that when inventory level is zero the arriving demands choose to enter the pool with probability β and with complementary probability (1- β) it is lost for ever. Finally it analyze an (s,S) production inventory system with switching time. A lot of work is reported under the assumption that the switching time is negligible but this is not the case for several real life situation.

Stochastic processes and their applications semi-markov analysis of some inventory and queuing problems

This thesis analyses certain problems in Inventories and Queues. There are many situations in real-life where we encounter models as described in this thesis. It analyses in depth various models which can be applied to production, storag¢, telephone traffic, road traffic, economics, business administration, serving of customers, operations of particle counters and others. Certain models described here is not a complete representation of the true situation in all its complexity, but a simplified version amenable to analysis. While discussing the models, we show how a dependence structure can be suitably introduced in some problems of Inventories and Queues. Continuous review, single commodity inventory systems with Markov dependence structure introduced in the demand quantities, replenishment quantities and reordering levels are considered separately. Lead time is assumed to be zero in these models. An inventory model involving random lead time is also considered (Chapter-4). Further finite capacity single server queueing systems with single/bulk arrival, single/bulk services are also discussed. In some models the server is assumed to go on vacation (Chapters 7 and 8). In chapters 5 and 6 a sort of dependence is introduced in the service pattern in some queuing models.

Sustainable Development through the Environment Management Tool Ecological Footprint Analysis – A Study in Kochi City, India

In the past, natural resources were plentiful and people were scarce. But the situation is rapidly reversing. Our challenge is to find a way to balance human consumption and nature’s limited productivity in order to ensure that our communities are sustainable locally, regionally and globally. Kochi, the commercial capital of Kerala, South India and the second most important city next to Mumbai on the Western coast is a land having a wide variety of residential environments. Due to rapid population growth, changing lifestyles, food habits and living standards, institutional weaknesses, improper choice of technology and public apathy, the present pattern of the city can be classified as that of haphazard growth with typical problems characteristics of unplanned urban development. Ecological Footprint Analysis (EFA) is physical accounting method, developed by William Rees and M. Wackernagel, focusing on land appropriation using land as its “currency”. It provides a means for measuring and communicating human induced environmental impacts upon the planet. The aim of applying EFA to Kochi city is to quantify the consumption and waste generation of a population and to compare it with the existing biocapacity. By quantifying the ecological footprint we can formulate strategies to reduce the footprint and there by having a sustainable living. In this paper, an attempt is made to explore the tool Ecological Footprint Analysis and calculate and analyse the ecological footprint of the residential areas of Kochi city. The paper also discusses and analyses the waste footprint of the city. An attempt is also made to suggest strategies to reduce the footprint thereby making the city sustainable

Ecological Footprint Analysis – An Overview

In the past, natural resources were plentiful and people were scarce. But the situation is rapidly reversing. According to the Living Planet Report 2006, during the last thirty years, consumption of natural resources has increased 40%, while Earth’s natural wealth in biodiversity has decreased 30%. Our challenge is to find a way to balance human consumption and nature’s limited productivity in order to ensure that our communities are sustainable locally, regionally and globally. Ecological Footprint Analysis (EFA) is physical accounting method, developed by William Rees and M. Wackernagel (1992), focusing on land appropriation using land as its “currency”. It provides a means for measuring and communicating human induced environmental impacts upon the planet. In this paper, an attempt is made to explore the tool Ecological Footprint Analysis. The paper also analyses the methods for calculating ecological footprint, scope of the tool as an impact assessment tool for India and measure for reducing the ecological footprint