I Gede Agus Widyadana

An economic production quantity model for deteriorating items with preventive maintenance policy and random machine breakdown

In recent years, many researches on economic production quantity (EPQ) models with machine breakdown and preventive maintenance have been developed, but few of them have developed integrated models for deteriorating items. In this study, we develop EPQ models for deteriorating items with preventive maintenance, random machine breakdown and immediate corrective action. Corrective and preventive maintenance times are assumed to be stochastic and the unfulfilled demands are lost sales. Two EPQ models of uniform distribution and exponential distribution of corrective and maintenance times are developed. An example and sensitivity analysis is given to illustrate the models. For the exponential distribution model, it is shown that the corrective time parameter is one of the most sensitive parameters to the optimal total cost.

Optimal Inventory Policy for Stochastic Demand Using Monte Carlo Simulation and Evolutionary Algorithm

Research on inventory models has been conducted intensively, including the model for stochastic demand. However, inventory models for stochastic demand are not easy to solve using an exact algorithm. In this paper, we develop a Monte Carlo simulation method to solve inventory problems with stochastic and intermittent demand. Simulation is conducted to evaluate continuous and periodic review policies. The simulation models are optimized using the evolutionary algorithm. The models are applied to data from one bicycle shop in Indonesia for five different items. The result shows that the economic order quantity ( R,Q ) policy is better than the ( s,S ) policy for two items and it is better than the ( S,T ) policy for three items.

Analyzing Humanitarian Logistic Coordination for Disaster Relief in Indonesia

Humanitarian logistics have been given an attention in recent years since logistic is one of important factors in effective disaster response and disaster relief. There are few researches on humanitarian logistic in Indonesia. In this paper, we aim to map and analyze humanitarian logistic in Indonesia. Therefore, deep interview method has been done to interview some institutions in humanitarian logistic system. We analyze the coordination of humanitarian logistic system using RASIC method. The finding of the deep interview reveals the private sector actively participates in disaster relief. In particular, it is also found the private sector actively participates in disaster relief but they do not collaborate with BNPB. It can be concluded the private sectors are able to take on the role in Indonesia humanitarian logistic system under supervision of BNPB. We finally proposed the RASIC model involving the private sector for Indonesia humanitarian logistic.