a r t i c l e i n f o The optimal replenishment policy for an economic production quantity (EPQ)-based inventory model with nonconforming items and breakdown is presented. A real-life production system inevitably generates nonconforming items and has equipment breakdowns owing to process deterioration or other uncontrollable factors. This study addressed these issues in an EPQ-based system to o...

We consider the approximate solution of discrete optimization problems using procedures that are capable of magnifying the effectiveness of any given heuristic algorithm through sequential application. In particular, we embed the problem within a dynamic programming framework, and we introduce several types of rollout algorithms, which are related to notions of policy iteration. We provide cond...

We consider an M/G/1 quening system, where batches of customers are assumed to arrive the system according to a compound Poisson process. As soon as the system becomes empty, the server takes a vacation for a random length of time called vacation time to do other jobs, which is uninterruptible. After returning from that vacation, there are two possibilities viz. (i) he keeps on taking vacations...

This paper presents a wireless network performance study of a modified TCP/IP protocol stack with a network coding layer inserted between the transport and the network layer. The simulation was performed with the OPNET simulation tool and considered a heterogeneous wireless environment where a mobile device could connect to both LTE (Long Term Evolution) and WLAN (wireless LAN) networks. We sim...

We study the performance of methods of lines combining discontinuous Galerkin spatial discretizations and explicit Runge-Kutta time integrators, with the aim of deriving optimal Runge-Kutta schemes for wave propagation applications. We review relevant Runge-Kutta methods from literature, and consider schemes of order q from 3 to 4, and number of stages up to q + 4, for optimization. From a user...

In this article, the authors introduce a simple approach for modeling and analyzing a SII G / / 1 queue where the server may take repeated vacations. When a busy period ends, the server takes a vacation of random duration. At the end of each vacation, the server may either start a new vacation or resume service. If a queue is found of less than n customers, the server will always take a new vac...

In this paper, we consider a newsvendor who is going to invest on dedicated or flexible capacity, our goal is to find the optimal investment policy to maximize total profit while the newsvendor faces uncertainty in lead time and demand simultaneously. As highlighted in literature, demand is stochastic, while lead time is constant. However, in reality lead time uncertainty decreases newsvendor's...

This paper studies a loss and delay queueing model under the restriction of N-policy for the situations where arrival and service of customers are correlated and follows a bivariate Poisson process. When there is no customer present in the system then the server goes on vacation and returns back in the system whenever the specified N (>1) or more customers are accumulated. The server may breakd...

We consider an age-replacement model with minimal repair based on a cumulative repair cost limit and random lead time for replacement delivery. A cumulative repair cost limit policy uses information about a system's entire repair cost history to decide whether the system is repaired or replaced; a random lead time models delay in delivery of a replacement once it is ordered. A general cost mode...

We consider the problem of long term power allocation in dense wireless networks. The framework considered in this paper is of interest for machine-type communications (MTC). In order to guarantee an optimal operation of the system while being as power efficient as possible, the allocation policy must take into account both the channel and queue states of the devices. This is a complex stochast...