Copyright (c) 2009 All rights reserved. http://works.bepress.com/hakan_tarakci Recent documents in Hakan Tarakci en-us Thu, 08 Oct 2009 10:11:22 PDT 3600 http://works.bepress.com/hakan_tarakci/8 http://works.bepress.com/hakan_tarakci/8 Thu, 04 Sep 2008 05:27:30 PDT 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 with the trade off being between accuracy/quality and cost. Using a heuristic proposed in queuing theory, we provide the optimal investment in telemedicine technology together with the staffing policy, considering the various cost components, including staffing, technology investment, incorrect treatment, and waiting. The model also incorporates buy-in by the patients in the form of the arrival (show-up) rate dependent on the technology level established. We find that under certain conditions the hospital should not invest in telemedicine. Finally, we provide the optimal tele-specialist policy of the ratio of patients to treat via telemedicine and to refer to the face-to-face consultation. Our model also suggests that a policy of treating all patients via tele-medicine is never optimal. Hakan Tarakci BUSINESS ADMINISTRATION, MANAGEMENT (0454) OPERATIONS RESEARCH (0796) http://works.bepress.com/hakan_tarakci/7 http://works.bepress.com/hakan_tarakci/7 Wed, 17 Oct 2007 06:13:27 PDT We discuss channel coordination in maintenance outsourcing contracts. We consider a service chain, including a manufacturer and a maintenance contractor that performs the manufacturer's maintenance functions. The manufacturer wishes to maximize uptime whereas the contractor aims to minimize cost. Realizing the two parties have different goals, we propose three coordination methods for inducing the contractor to select the maintenance policy that optimizes the profit of the service chain. Hakan Tarakci http://works.bepress.com/hakan_tarakci/6 http://works.bepress.com/hakan_tarakci/6 Wed, 17 Oct 2007 06:10:48 PDT In this paper, we discuss learning in maintenance outsourcing. We consider a manufacturer that outsources its maintenance activities to a contractor. We find that a payment scheme consisting of a fixed amount along with cost subsidization (CS) can maximize the manufacturer's profit under no learning. If the contractor achieves learning through experience, CS still maximizes the manufacturer's profit. If learning happens with costly effort, CS is still effective under special conditions. Hakan Tarakci http://works.bepress.com/hakan_tarakci/5 http://works.bepress.com/hakan_tarakci/5 Tue, 16 Oct 2007 05:35:54 PDT 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 staffing, incorrect treatment, and waiting. We also find the optimal investment in telemedicine technology that offers the best trade-off between the quality and accuracy of telemedicine services and the cost of technology. Under certain conditions, the hospital does not offer any telemedicine services. When it does, it may or may not invest in the most advanced technology available. Finally, we provide the optimal tele-specialist policy of which patients to treat remotely via telemedicine and which patients to refer to the experts for a face-to-face consultation. We show that a policy of treating all patients via tele-medicine is never optimal. Hakan Tarakci http://works.bepress.com/hakan_tarakci/4 http://works.bepress.com/hakan_tarakci/4 Tue, 16 Oct 2007 05:19:08 PDT 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 payment to the contractor consists of a fixed amount along with cost subsidization for each maintenance operation performed. We assume learning occurs when the contractor performs preventive maintenance that reduces both time and cost. Two types of learning are considered: natural learning and learning by costly efforts. We demonstrate that a well-designed payment scheme can induce the contractor to adopt the maintenance schedule that maximizes the manufacturer's profit. Hakan Tarakci BUSINESS ADMINISTRATION, MANAGEMENT (0454) OPERATIONS RESEARCH (0796) ECONOMICS, COMMERCE-BUSINESS (0505) http://works.bepress.com/hakan_tarakci/3 http://works.bepress.com/hakan_tarakci/3 Tue, 16 Oct 2007 05:15:32 PDT 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 incentive contract is offered to each contractor, consisting of an uptime target level and a bonus rate for exceeding the uptime target. Under the incentive contract, a contractor receives a bonus only when the achieved uptime exceeds the target level specified in the contract. We develop a model for jointly determining the uptime target levels and bonus rates for the contractors which maximize system profit. We also demonstrate the financial benefits of coordination and added flexibility in allocating the additional profit to the contractors. In addition we show the impact of the variation in individual process maintenance times and costs on channel coordination and profits. Hakan Tarakci BUSINESS ADMINISTRATION, MANAGEMENT (0454) OPERATIONS RESEARCH (0796) ECONOMICS, COMMERCE-BUSINESS (0505) http://works.bepress.com/hakan_tarakci/2 http://works.bepress.com/hakan_tarakci/2 Tue, 16 Oct 2007 05:10:37 PDT 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 (ii) corrective maintenance is used to restore the process to a specified condition when it fails. We consider the use of incentive contracts to induce the contractor to select the maintenance policy that optimizes the total profit of the manufacturer and contractor. It is demonstrated that an incentive contract based on a combination of a target uptime level and a bonus always leads to the desired win-win coordination, and provides flexibility in allocating the extra profit generated from coordination and, importantly, an incentive to the contractor to improve the efficiency of the maintenance operations. The incentive contract can also be used to select the most economically efficient contractor frommultiple contractors with different maintenance capabilities. Hakan Tarakci BUSINESS ADMINISTRATION, MANAGEMENT (0454) OPERATIONS RESEARCH (0796) ECONOMICS, COMMERCE-BUSINESS (0505) http://works.bepress.com/hakan_tarakci/1 http://works.bepress.com/hakan_tarakci/1 Tue, 25 Sep 2007 17:09:14 PDT In the first part of this thesis, we consider a manufacturer who has a process with an increasing failure rate over time. In order to improve the performance of the process, the following two types of maintenance activities are outsourced to an external contractor: (a) Preventive maintenance (PM) is performed periodically to improve the reliability of the process when the process is functional, and (b) corrective maintenance (CM) is used to restore the process to a specified condition when it fails. We consider three incentive contracts for inducing the contractor to select the maintenance policy that optimizes the total profit of the manufacturer and contractor. It is demonstrated that an incentive contract, based on a combination of a target uptime level and a bonus, (i) always leads to the desired win-win coordination, (ii) provides flexibility in allocating the extra profit generated from coordination, (iii) motivates the contractor and the manufacturer to continuously improve efficiency of maintenance operations, and (iv) is able to coordinate the improved system most of the time. In the second part of the thesis, we extend the one manufacturer - one maintenance contractor setting. We consider a manufacturer who has a process consisting of multiple stages. The manufacturer's revenue is determined by the minimum of uptimes among the manufacturing stages. The maintenance functions-preventive maintenance and corrective maintenance-of the manufacturing stages are outsourced to independent contractors. In order to achieve channel coordination in the maintenance chain, the manufacturer may offer incentive contracts to some or all of the contractors, depending on the failure rate functions, costs, and times associated with preventive maintenance and corrective maintenance. We propose using the incentive contract with uptime target level and bonus, defined in the first part of the thesis. In this research, we (a) develop a model for jointly determining the uptime target levels and bonus rates for the contractors which maximize system profit, (b) demonstrate the financial benefits of coordination and added flexibility in allocating the additional profit to the contractors, and (c) show the impact of individual stage maintenance times and costs on channel coordination and profits. Hakan Tarakci BUSINESS ADMINISTRATION, MANAGEMENT (0454) OPERATIONS RESEARCH (0796) ECONOMICS, COMMERCE-BUSINESS (0505)