Hakan Tarakci

• Professor at University of North Texas

This research examines maintenance outsourcing in the presence of cyber-attacks. The research findings contribute to the literature on maintenance outsourcing by considering how cyber-attacks affect channel coordination and, specifically, cost subsidization. The Internet of Things assumes the risk that a “smart” or connected manufacturing system co...

Teaching relatively complex quantitative topics in statistics, operations management, and management science to undergraduate as well as graduate students can pose numerous pedagogical challenges. However, several topics in these disciplines are amenable to exposition by means of dynamic interactive visualizations. We present a sample of such visua...

In this paper, we analyse the due-date-to-promise problem for a supplier who supplies parts to his customer. The parts are produced on an unreliable machine with constant production rate. The machine is leased from a contractor who is also entrusted with its maintenance. The supplier's decision is the optimal due date to promise to his customer, ta...

In this paper, we study a healthcare system consisting of a healthcare provider and a patient. We first look at a patient with a chronic condition, such as asthma or diabetes, where the patient needs to go through a restorative treatment when she falls sick and through an occasional full treatment. We assume that the health condition of the patient...

This paper studies a manufacturer with a system prone to failure. The manufacturer performs two types of maintenance activities: preventive maintenance (PM), performed periodically, resets the system, and Minimal Repair (MR), performed after breakdowns, restores the system to working condition. It is assumed that two different types of learning tak...

To avoid stockouts and maintain product availability, retailers typically carry excess units and subsequently incur higher cost. In case of style/fashion goods, demand forecasting is extremely difficult due to short selling cycles. The purpose of this study was to minimise the cost of excess stocking without compromising product availability. To ac...

This article presents a study on the long-term (i.e., steady-state, convergence) characteristics of workers' skill levels under learning and forgetting in processing units in a manufacturing environment, in which products are produced in batches. Assuming that all workers already have the basic knowledge to execute the jobs, workers learn (accumula...

In this paper, we consider a system with multiple components, each prone to failure, during which production is halted. Minimal repair is performed by an external contractor whenever a component breaks down. The contractor also conducts a general preventive maintenance (PM) for the whole system at pre-determined times. The contractor's goal is to m...

In this paper, we provide a simple approximation scheme for the optimal objective value for a particular type of location problem. Typically, such problems are solved using the classic set covering formulation. Such a formulation automatically requires data for the constraint matrix and can get too large to implement or too difficult to solve to op...

We study the effects of learning and forgetting on the design of maintenance outsourcing contracts. Consider a situation in which a manufacturer offers an outsourcing contract to an external contractor for maintaining a manufacturing process. Under the contract, the contractor schedules and performs preventive maintenance and repairs the process wh...

We study a specialty hospital providing traditional face-to-face consultations by experts and telemedicine services by tele-specialists. As accuracy of diagnosis and treatment by tele-specialists are paramount in such a setting (unlike call center management), our main focus is to determine the optimal investment level in telemedicine technology wi...

The objective of this paper is to study learning effects on maintenance outsourcing. We consider a situation in which a manufacturer offers a short-term outsourcing contract to an external contractor who is responsible for scheduling and performing preventive maintenance and carrying out minimal repairs when the process fails. The manufacturer's pa...

We study the optimal strategy of a specialty hospital in providing traditional face-to-face consultations via experts and remote medical services via tele-specialists. We model the whole system as a queuing problem and provide the optimal staffing policy for this hospital by taking into account the various cost components, such as those for staffin...

Consider a manufacturer who has a process with an increasing failure rate over time. In order to improve the process performance, the following two types of maintenance activity are outsourced to an external contractor: (i) preventive maintenance is performed periodically to improve the reliability of the process when the process is functional; and...

Consider a manufacturer with a manufacturing system that consists of multiple processes. The manufacturer's revenue is determined by the minimum of the uptimes among the processes. The maintenance functions of the processes are outsourced to independent contractors so that each contractor is responsible only for one process. A performance-based inc...