Variable Deterioration Rate Research Articles

Service life prediction of timber-concrete composite floors

Timber-concrete composite (TCC) systems have application for new floors and for upgrading and enhancing of existing timber floors in residential and office buildings. In order to develop the optimal maintenance programs of structures, it is essential to predict the performance of structures over their life-cycle. The long-term behavior of timber-concrete composite floors is influenced by a combination of various factors, including material properties, load distribution, moisture effects, temperature effects and durability considerations. Timber and concrete material in the composite system, exhibit different behaviors over time due to their inherent characteristics. Deterioration prediction models are used to estimate the future degradation and condition of various types of structures. The aim of this paper is to present two probabilistic models, random variable deterioration rate model and stochastic gamma process model, that will capture uncertainty and variability associated with the deterioration of TCC floor under the service load and to estimate its service life.

A Healthcare Divisions Inventory Model for Deteriorating Items with a Variable Deterioration Rate Under Permissible Delay in Payments

A Healthcare Divisions Inventory Model for Deteriorating Items with a Variable Deterioration Rate Under Permissible Delay in Payments

An Inventory Model for Weibull Distributed Deteriorating Items Under Ramp Type Demand and Permissible Trade Credit Policy

In a classical inventory economic order quantity (EOQ) model, the stock is depleted due to both market demand and deterioration. Many inventory models are developed for items under variable rate of deterioration. The two parameter Weibull distributed term is a representation of constant, time dependent linear and non-linear, increasing and decreasing rate of deterioration. Again the demand rate is assumed here as time dependent in beginning of cycle and then becomes constant as passage of time. Shortages are allowed and fully backlogged. Moreover the trade credit policy is a win-win payment strategy for sharing profit in the inventory system. This present paper deals with a replenishment policy assuming two parameter Weibull distributed deteriorating items, demand rate a ramp type function of time under permissible trade credit policy. Finally several numerical examples are given to illustrate the model and some particular cases are also discussed along with its’ illustrations along with concluding remarks. Keywords: Inventory, Weibull distribution, deterioration, ramp type, trade credit and shortages. Subject classification: AMS Classification No. 90B05 DOI: 10.7176/EJBM/13-19-03 Publication date: October 31 st 2021

An Optimal Policy for Items with Linear Demand Rate, Variable Deterioration Rate Under Shortage and Lead-Time

In this research, we have developed a deterministic inventory model for an item having linear demand in variable deterioration rate. The shortage is allowed and fully backlogged. In developing the model, we have assumed that lead time is not equal to zero. Here we developed an optimal policy that minimizes that the total average cost. The model is illustrated by a suitable numerical example and sensitivity analysis has been carry- out.

Block-chain application Based Economic impact of Coronavirus pandemic on Medicine industry inventory System for Deteriorating objects with two-warehouse and wastewater treatment using PSO

In this paper, the determined economic impact of the Medicine industry of the Coronavirus pandemic for aggravating items with a ramp-type demand with inflation effects in two-warehouse storage devices and wastewater treatment cost using PSO is developed. The owned warehouse has a fixed capacity of W units; rented warehouse has unlimited capacity. Here, we hypothesized that the Block chain Economic Impact of the Coronavirus Pandemic Medicine Industry in Inventory Cost of Inventory in RW is greater than that in OW using PSO. The shortcomings of the economic impact of the Coronavirus pandemic Medicine industry are allowed and partially lagged behind, and it is assumed that Block chain’s economic impact of the Coronavirus medicine pandemic industry decreases over time with a variable deterioration rate and wastewater treatment cost using PSO. The effect of inflation was also considered due to the different costs associated with Blockchain applying the Economic Impact of the Coronavirus Medicine Industry Inventory System and wastewater treatment cost using PSO. The numerical sample is also used to study the behavior of the model using particle size optimization. The cost minimization technique is used to obtain expressions for total costs and other parameters.

Tabu search problem application based economic impact of coronavirus pandemic on sugar industry inventory system for deteriorating objects with two-distribution center and waste-material treatment

In this paper, the determined economic impact of the Sugar industry of the Coronavirus pandemic for aggravating items with a ramp-type demand with inflation effects in two-Distribution center storage devices and waste-material treatment cost using Taboo Search is developed. The owned Distribution center has a permanent ability of W units; rented Distribution center has unlimited capacity. Here, we hypothesized that the Block chain Economic Impact of the Coronavirus Pandemic Sugar Industry in Inventory Cost of Inventory in RW is greater than that in owned Distribution center using Taboo Search. The shortcomings of the economic impact of the Coronavirus pandemic Sugar industry are allowed and partially lagged behind, and it is assumed that Block chain’s economic impact of the Coronavirus Sugar pandemic industry decreases over time with a variable deterioration rate and waste-material treatment cost using Taboo Search. The effect of inflation was also considered due to the different costs associated with Taboo Search applying the Economic Impact of the Coronavirus Sugar Industry Inventory System and waste-material treatment cost using Taboo Search. The mathematical sample is as well used to study the performance of the model using particle size optimization. The cost minimization technique is second-hand to get hold of expressions for total costs and erstwhile parameters.

Analysis of Inventory Model with Time Dependent Quadratic Demand Function Including Time Variable Deterioration Rate without Shortage

This paper deals with an inventory model for deteriorating items along with time dependent demand which is quadratic function of time. In this model, the deterioration rate follows deterministic deterioration which is quadratic function of time. Here shortages are not allowed. The main purpose of this paper is to investigate minimum total cost per unit time of the inventory model. The result are validated with the help of numerical example. The sensitivity analysis of the optimal solution with respect to various parameters is carried out. Finally the behavior of the relation between parameters and total inventory cost have been shown using figure.

Preservation technology investment for an inventory system with variable deterioration rate under expiration dates and price sensitive demand

The proposed study addresses a supplier-retailer inventory problem by considering the detrimental impacts of deterioration. The inventory produced by the supplier undergo a machine-shift and hence, produces non-conforming items. The retailer uses the preservation technology to deal with deteriorating items ingeniously where the demand is price-sensitive at the buyers end. Two models are developed through different means viz. Integrated and Bi-level approach and compared so to impart some constructive organizational insights. Sensitivity analysis was done over a numerical example to validate strength of the developed models.

Optimal Inventory Management System for Deteriorating Items with Linear Demand, Shortages and Partial Backlogging in a Triangular Fuzzy Setup

In the present communication, we have proposed an optimal inventory management system for deteriorating items with linear demand, shortages, variable rate of deterioration and partial backlogging in the fuzzy environment. In real life situations, we certainly face the uncertainty component associated with the different parameters such as demand, raw materials supply, various other inventory costs, rate of deterioration, etc. Uncertainty theory in fuzzy terms has been found to be a useful methodology to describe the inherent subjective indeterminacy. The objective of the present work is to optimise the total average cost function by taking triangular fuzzy numbers into account. The defuzzification methods viz. graded mean, signed distance and centroid have been applied to obtain the results of the proposed model. For a detailed illustration of the proposed model, an example of inventory model has been considered and solved in view of the parameters involved. Further, the sensitivity analysis with respect to the various influencing parameters have been presented with the help of some graphical representations. The paper is finally concluded with a scope for the possible future work.

Time-dependent Reliability Analysis of Timber-Concrete Composite Beams

Timber-concrete composite system is increasing the use of timber in construction because some structures could not be built by timber alone, but it becomes possible with this composite system. The deterioration of structures in service is generally uncertain over time, therefore the appropriate approach for the structural analysis is a time-dependent reliability analysis that considers the randomness and uncertainties of deterioration process over a time period. This paper describes two methods for time dependent reliability analysis, random variable deterioration rate model and gamma process model, and compares the deterioration prediction as well as service life estimation of timber-concrete composite beams under normal use based on proposed models.

Deterministic inventory model for items with linear demand, variable deterioration and partial backlogging

A deterministic inventory model is developed for a deteriorating item having linear demand and variable deterioration rate. Shortages are allowed and partially backlogged. In developing the model we have assumed that the rate of backlogging is variable and dependent on the waiting time for the next replenishment. The objective of the model is to develop an optimal policy that minimises the total average cost. Suitable numerical example has been discussed to understand the problem. Sensitivity analysis has been carried out to show the effect of changes in the parameter on the optimum total average cost.

Deterministic inventory model for items with linear demand, variable deterioration and partial backlogging

A deterministic inventory model is developed for a deteriorating item having linear demand and variable deterioration rate. Shortages are allowed and partially backlogged. In developing the model we have assumed that the rate of backlogging is variable and dependent on the waiting time for the next replenishment. The objective of the model is to develop an optimal policy that minimises the total average cost. Suitable numerical example has been discussed to understand the problem. Sensitivity analysis has been carried out to show the effect of changes in the parameter on the optimum total average cost.

An inventory model of deteriorating item for maximization of profit

In this paper, a model is developed for a deteriorating item having exponential demand rate in the first part of the cycle and constant demand rate in the second part of the cycle with time variable deterioration rate. Time period of the cycle is obtained for maximum profit.

Supply chain model with stock dependent demand, quadratic rate of deterioration with allowable shortage

The goal of this devotion of time and attention to acquiring knowledge is to develop assist calculations and prediction for supply chain (three echelons), in which an optimal ordering decision for the manufacturer–supplier–retailer chain is developed when the supplier's lead–time is considered. This paper examines deterministic inventory model with variable deterioration and stock dependent demand, where the unsatisfied demand is partially backlogged which depends on waiting time. A solution procedure is presented to determine a stock dependent demand, variable deterioration rate, shortage period and the demand during the shortage is partially backlogged which is dependent on the waiting time such that the difference between an initial outlay and the subsequent amount earned for the supply chain is maximised. Sensitivity analyses are given to illustrate the model with the help of profit maximum principle.

A discrete-in-time deteriorating inventory model with time-varying demand, variable deterioration rate and waiting-time-dependent partial backlogging

A new inventory system is considered for deteriorating items in which unsatisfied demands are partially backlogged depending on the waiting time until the next replenishment and deterioration rates are constant, but different from period to period. Time is considered as a discrete variable, which better represents some real-life scenarios. An optimal solution can be easily derived. A sensitivity study is provided through substantial numerical experiments to illustrate the use and robustness of the proposed model. The sensitivity analysis reveals some useful and significant insights.

An EOQ Model for Deteriorating Items with Linear Demand, Variable Deterioration and Partial Backlogging

In this paper, an economic order quantity (EOQ) model is developed for deteriorating items with linear demand pattern and variable deterioration rate. Shortages are allowed and partially backlogged. The backlogging rate is variable and dependent on the waiting time for the next replenishment. The objective of the model is to develop an optimal policy that minimizes the average total cost. The numerical example is used to illustrate the developed model. Sensitivity analysis of the optimal solution with respect to various parameters is carried out.

An EOQ model for a deteriorating item with time dependent quadratic demand and variable deterioration under permissible delay in payment

In a recent paper, Khanra, Ghosh and Chaudhuri’s (2011) presented an EOQ model for a deteriorating item with time dependent quadratic demand under permissible delay in payment. Deterioration considered in most of the EOQ models is constant, while in most of the practical cases the deterioration rate increases with time. This work is motivated by Khanra, Ghosh and Chaudhuri’s (2011) paper extending their model to allow for a variable rate of deterioration when delay in payment is permissible. The time varying demand rate is taken to be a quadratic function of time. For settling the account, the model is developed under two circumstances: case-1: The credit period is less than or equal to the cycle time and case-2: the credit period is greater than the cycle time. A numerical example is provided to illustrate the model. Sensitivity analysis has also been conducted to study the effect of the parameters.

An Optimal Inventory Policy for Items having Linear Demand and Variable Deterioration Rate with Trade Credit

Problem statement: Demand considered in most of the classical inventory models is constant, while in most of the practical cases the demand changes with time. In this study model has been framed to study the items whose demand changes with time and deterioration rate increases with time. The effect of permissible delay is also incorporated in this study. The objective of this research is to develop an inventory model for perishable items whose perish-ability rate as well as demand increases with time Approach: Firstly, problem is framed in the form of linear differential equation model and this model had been solved using general solution techniques of linear differential equations. The solution obtained gives the inventory level at any particular time of the cycle period. With the help of this inventory level, total as well as average inventory cost has been obtained. Results: This study developed a model to determine an optimal order quantity by using calculus technique of maxima and minima. Thus it helps retailer to decide its optimal ordering quantity under the constraints of variable deterioration rate and linear pattern of demand. Conclusion: Numerical solution of the suggested model had also been proposed, the above model can be converted into constant demand model, or for items having no deterioration. This study can further be extended for items having some other demand pattern, also time value of money and inflation can be incorporated in this model to make it more realistic and present business environment suited.

An order level inventory model with variable rate of deterioration and alternating replenishing rates considering shortages

In production inventory systems, there are situations in which it is not possible to have single rate of production through out the production period. Items are produced at different rates during sub- periods so as to meet various constraints that arise due to change in demand pattern, market fluctuations etc. This paper models such a situation by assuming constant rate of demand and varying rates of production. Also, attempts have been made to investigate the model for items that deteriorates according to a special form of Weibull density function for time allowing shortages. In all cycles special cases are discussed. Results are illustrated by numerical examples.

Collaborative normal tension glaucoma study.

Before this study was done, there was a difference of opinion concerning whether intraocular pressure (IOP) was involved in producing optic nerve damage when there was glaucomatous damage to the optic nerve and characteristic visual field loss, even though the IOP was in the statistically normal range. This article reviews the findings of a collaborative study aimed at finding the answer to this question. The level of pressure influences the course of normal tension glaucoma, as evidenced by a slower rate of incident visual field loss in cases with 30% or more lowering of intraocular pressure. The rate of progression without treatment is highly variable, but often slow enough that half of the patients have no progression in 5 years. A faster rate occurs in women, in patients with migraine headaches, and in the presence of disc hemorrhages. Some patients may experience greater benefit from lowering of IOP than others, but further research is needed to be able to identify those most likely to benefit. As a group, patients with normal tension glaucoma benefit from lowering of IOP. Variable rate of deterioration, as well as lack of progression in a substantial number in 5 years, suggest that treatment should be individualized according to the stage of disease and rate of progression. Traits that help predict risk and rate of progression and response to treatment are beginning to become known and, when fully known, will help guide management decisions.