Catálogo de publicaciones - libros

The capability to efficiently manage product-variety is nowadays a critical success factor for many companies. However, existing models still lack a suitable support for mapping and analyzing variant productions. The paper contributes to this area with a comprehensive but practicable approach. Product families are defined through common attributes with differentiating characteristics. Product structures and process plans of variants belonging to the same product family are represented using generic “plan skeletons”. It is shown how the approach can thereby reduce modeling efforts and enhance the clarity of the resulting model. Furthermore, linking such a model to a simulation allows for assigning performance indicators to the product family’s attributes instead of many product variants. Variant-induced costs can thus be disclosed as additional costs compared to a base product for each characteristic.

This paper presents a method of integrating activity-based costing (ABC) and process simulation in human planning. Our studies have already proposed a method of integrating ABC and process simulation in business process reengineering (BPR) and showed a case study of a chemical plant. Some studies have also already showed some examples of various aspects in manufacturing systems. Although a large number of studies have been made on product-mix/machine loading or scheduling, little is known about human planning. In this paper, effective BPR methodologies to achieve dramatic improvements in business measures of workers’ skills and costs based on ABC are discussed. First, two important tools: process simulation method and ABC analysis that can be customized by organizations for their own BPR are shown. As these tools have been separately used, a unified approach of process simulation and ABC analysis for process redesigns based on simulation. Secondly, a method of process simulation design is shown. It is repeated to consider working ratio and running time of resources. Thirdly, a method of ABC analysis that can be customized by organizations is shown. It automatically shows the data that has been gathered from many sources. By utilizing the data, the process simulation is implemented, and the result of simulation gives the data to ABC analysis. Lastly, this paper shows a case study in BPR and the effectiveness of our method.

The uncertain quality of used products highly affects the performances of remanufacturing systems and quality of remanufactured products. Hence the quality issues of used product cannot be neglected in remanufacturing. To apply the quality concept into remanufacturing system control or simulation, individual management of each product is required. To this end, a multi-agent approach can provide good solutions. The first step in applying the quality concept with the multi-agent approach is an effective modeling of a remanufacturing system. This study proposes a methodology for modeling a quality embedded remanufacturing system (QRS) with two layers. The first layer represents elements in a remanufacturing system as it is. The representation also contains the information of a multi-agent structure for a QRS. The second layer expresses the status of each product and resource agent, and their relationships to manage the multi-agent system. As modeling tools to support the proposed methodology, directed graphs and Petri-Nets are used. A case study is introduced to show an application of the proposed methodology.

In the last years, given the high market pressure and the increased competition in several industries, the search for new business opportunity is focusing on service activities. After-Sales (AS) service has become increasingly important as a source of differentiation and market share for manufacturers and resellers, as well as a strategic driver for customer’s retention. These changes often call for a new conceptual definition of the product-service bundle marketed to the final customer and for a thorough revision of the logistical and organizational configuration of the whole service chain. It comes out the necessity to design appropriate processes and to have a general and shared definition of their structure. Aim of the paper is to suggest a model which provides a common configuration of the assistance processes according to a framework that links the different typologies of assistance with the product service strategies offered by companies. Some case studies have been considered in order to validate the proposed framework and the model.

A system dynamics model is proposed to analyze the human role in planning and scheduling. Based on the interview research results planning and scheduling activities in manufacturing companies are investigated. By selecting important elements in planning and scheduling, a model of the human role is developed assuming a simple manufacturing environment. Two modes of the model is examined in the simulation experiments, and the results indicate the importance of the human role in smoothing the workload by look-ahead decisions and in reducing the uncertainty by collecting information and coordinating planning and scheduling activities.

A formal modeling technique, based on colored timed Petri net and UML static structure modeling languages is used to teach students to model their business process problem as a discrete event system, before they build a working simulation model in a simulation tool (in our case Arena). Combining Petri net and UML static structure diagrams, one can build an abstract, well defined and complete model. This model enables the simulation analyst to make an unambiguous, complete and yet easily readable model of the target operational process. The two most important classes of decisions that are reflected in the conceptual model are the choice of the real world details to be taken in or left out the model and the precise specification of the output parameters of the simulation. This paper describes the modeling technique and discusses its value in teaching and in the formulation of decision problems regarding operational processes.

The after-sales services and in particular the spare parts business have acquired, in recent years, a strategic role for firms manufacturing durable or capital goods, as they represent a source of revenue, profit and a mean to achieve customer satisfaction and retention. Nonetheless, the huge variety and the characteristics of the demand of spare parts make the configuration and management of the spare parts inventory and distribution systems critical decision areas for managers. These decisions, in fact, may lead to very different cost and service performance by the system itself. The case study analyzed concern a world player of heavy equipment based in Sweden. Its spare parts distribution system is described, and the paper analyzes the configuration and allocation decisions concerning a second European warehouse and the transfer to that warehouse of a set of suppliers. A simulation model has been developed in order to support these choices. Discrete event simulation is well suited for studies where time-dependant relations are analyzed. Supply Chain Simulation applied to the case study provides useful insights on the decision choices and the cost structure related to the spare parts distribution system.

In the recent years, companies have begun to strengthen their supply agreements, such as sharing the management of inventories. This type of co-soperation implies that the members of the supply chain share information and arrange a mutual agreement on their performance targets. The increased interest on supply chain topics has attracted researchers’ attention to the problem of co-operation between the buyer and vendor, the two actors directly interacting in the supply mechanism. The present research investigates the way how a particular VMI policy, known as Consignment Stock (CS), may lead to a successful strategy for both buyer and vendor. The previous study [ 1 ] developed an analytical model of the CS policy, with reference to the centralised decision and deterministic settings. In order to fully explore the potentiality of CS policy, an extension of the model is proposed in this paper. The results indicate that the CS policy could be a strategic and profitable approach to improve supply chain performance in uncertain environments.

This paper describes a novel simulation framework that integrates discreteevent modeling with system-dynamics modeling. The former has strength in system performance evaluation; meanwhile, the later has an advantage of representing feedback mechanisms in complex systems. We are currently developing a hybrid-modeling framework, which combines discrete-event modeling with system dynamics modeling. The objectives of this framework are: (1) to simulate feedbacks of supply-chain activities in social system mechanisms, (2) to enable management simulation in long time terms, and finally (3) to clarify requirement specifications towards supply-chain management gaming. This paper summarizes this framework and represents application examples.

Growing market demands on enterprises and the resulting challenges for their organization have been discussed for many years now. The flexibility and mutability of an enterprise are thereby considered as a significant factor for success. As a reaction to this, many enterprises have realigned their enterprise along the value-added chain. The implementation of flat hierarchies and processoriented work organization make up focus of current discussions about organizational structures in the manufacturing area. New departmental structures, however, often require that decisions are delegated to operative positions, thus increasing the decision-making and action leeway of the operative employees. However, there are currently no methods capable of prospectively examining the suitability of such decentralized decision-making systems. In this context, this paper presents a method with which the suitability of decision-making systems can be examined in a prospective and quantitative manner. In order to attain this goal, the simulation procedure OSim-Ent developed at the ifab-Institute of Human and Industrial Engineering of the University of Karlsruhe (Germany), was expanded through generic elements, with which relevant decision-making system elements can be modeled and examined through simulation.