Scheduling policies for a repair shop problem

In this paper, we analyze a repair shop serving several fleets of machines that fail from time to time. To reduce downtime costs, a continuous-review spare machine inventory is kept for each fleet. A spare machine, if available on stock, is installed instantaneously in place of a broken machine. When a repaired machine is returned from the repair shop, it is placed in inventory for future use if the fleet has the required number of machines operating. Since the repair shop is shared by different fleets, choosing which type of broken machine to repair is crucial to minimize downtime and holding costs. The optimal policy of this problem is difficult to characterize, and, therefore, is only formulated as a Markov Decision Process to numerically compute the optimal cost and base-stock level for each spare machine inventory. As an alternative, we propose the dynamic Myopic(R) policy, which is easy to implement, yielding costs very close to the optimal. Most of the time it outperforms the static first-come-first-served, and preemptive-resume priority policies. Additionally, via our numerical study, we demonstrate that repair shop pooling is better than reserving a repair shop for each fleet

After-Sales Service Contracting for Excellence in Life-Cycle Cost Management: Numerical Experiments and Systematic Review of Analytical Models

This research adds to the literature and provides insight to practice via three essays that increase understanding about the applications and consequences of the two new approaches to the after-sales service governance: warranty contract and performance-based contracts. First, we attempted to enhance our knowledge of the modeling of the after-sales service process. In the first essay, the research papers with analytical models of after-sales services to present current trends, issues, and future research directions in the literature are classified. In the second essay, the effect of the warranty contract on the supplier's product quality improvement efforts in the context of capital goods is examined. Three sets of optimization models reveal that the existence of a warranty improves product quality. In the third essay, the performance-based contract is examined in the context of the warranty contract. The numerical experimentations conducted demonstrate that the performance-based contract is superior to the warranty contract in terms of the supplier's product quality efforts and the customer's total cost of after-sales services. The alignment of incentives based on the product performance tackles the issues presented in the traditional after-sales service contracting. Collectively, the three studies presented in this research expand our understanding of after-sales service contracts. Thus, the research presents managerial implications and adds to the existing body of knowledge in after-sales service research

La valoración de inversiones corporativas desde la perspectiva del capital intelectual : una aproximación multicriterio

El aumento de la complejidad en la definición y posterior adopción de estrategias corporativas, especialmente las relativas a las decisiones de inversión, es uno de los elementos más significativos derivados del escenario económico internacional en el que operan en la actualidad las empresas. Una serie de factores concretos explican esta circunstancia, tales como la intensificación de los problemas de agencia, el carácter multidimensional del factor riesgo, o la naturaleza intangible de buena parte de los beneficios que generan las inversiones de carácter estratégico adoptadas en el marco de la denominada economía del conocimiento. Todos estos factores de complejidad están condicionando la correcta y eficiente asignación de recursos en la empresa y los procesos de decisión que la modelan. Las técnicas financieras clásicas, que abordan la resolución de dichos procesos desde la perspectiva de la optimización de los atributos rentabilidad y riesgo, son en la actualidad criticadas por no considerar determinados beneficios intangibles que se derivan de los proyectos de inversión. El objetivo general de esta tesis doctoral es desarrollar un nuevo enfoque teórico de valoración de inversiones no financieras fundamentado en el constructo ampliamente aceptado de creación de valor de mercado entendido desde una perspectiva integral y completa. Este enfoque implica una redefinición del término creación de valor, incorporando a la generación de valor financiero la creación de valor no financiero o de capital intelectual, a la vista del decisivo protagonismo de los intangibles como fuente de valor y de ventaja competitiva sostenible. El enfoque teórico de valoración propuesto se articula a través de dos métodos de análisis multicriterio: el proceso analítico jerárquico y el proceso analítico en red. Ambos permiten integrar en el estudio tanto los criterios que inciden en la creación de valor financiero, como aquellos que contribuyen a la creación de valor no financiero o de capital intelectual. Esta integración permite que los dos modelos de valoración que aquí se proponen cuantifiquen el valor total que genera cada alternativa de inversión, con el fin de ayudar a los directivos en sus procesos de decisión corporativos. La metodología propuesta se implementa en dos casos de estudio de la industria agroalimentaria andaluza. El primero consiste en la valoración de tres alternativas de sistemas de gestión de la calidad en el sector cárnico y, en el segundo caso, se evalúan las posibles alternativas de sistemas de gestión ambiental en la industria almazarera. Los resultados de la implementación empírica, además de validar los modelos, han evidenciado la conveniencia de considerar los impactos de las inversiones sobre los activos intangibles de la empresa, pues estos determinan en el mundo real la selección de la alternativa de inversión óptima. Los dos métodos de valoración propuestos implican la formalización del proceso de valoración de inversiones no financieras que actualmente siguen los directivos en las empresas...Increasing complexity in terms of defining and subsequently adopting corporate strategies, especially those relating to investment decisions, is one of the most significant issues emerging from the international economic environment in which businesses operate today. A number of specific factors play a part in this situation, such as the intensification of agency problems , the multidimensional nature of the risk factor, or the intangible nature of many of the benefits generated by strategic investments within the so-called ‘knowledge economy’. All these factors of complexity affect the appropriate and efficient allocation of company resources and the decisionmaking processes that determine them. Classical financial techniques that seek to address these processes from the perspective of optimizing risk and return attributes are now criticized because this kind of analysis ignore several key intangible issues also involved in investment projects. The overall objective of this thesis is to develop a new theoretical approach to evaluating nonfinancial investments, based on the widely-accepted concept of ‘creating market value’, understood from a holistic, comprehensive perspective. This approach requires a redefinition of the term ‘value creation’ to incorporate the creation of nonfinancial value or intellectual capital alongside the concept of financial value creation. This reflects the decisive role of intangible benefits as a source of value and sustainable competitive advantage. The proposed theoretical valuation approach is applied via two multicriteria methods: the analytic hierarchy process and the analytic network process. These allow the inclusion in the analysis of both the criteria that influence the creation of financial value as well as those that contribute to the creation of nonfinancial value or intellectual capital. This integration allows the two proposed valuation models to quantify the total value generated by each investment alternative in order to assist decision-makers in corporate decision processes. The proposed methodology is implemented in two case studies of the Andalusian food industry. The first concerns the evaluation of three alternative systems of quality management in the meat sector, and the second case evaluates possible alternatives for environmental management systems in the olive oil industry. The results of the empirical implementation, as well as validating the models, demonstrate the merits of considering the impact of investments on an organization’s intangible assets, as these influence the selection of the optimal investment alternative in the real world. The two proposed methods of assessment involve formalizing the current process of evaluating nonfinancial investments carried out by a company’s decision makers..