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Reiner, Gerald
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Reiner, Gerald
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Voici les éléments 1 - 2 sur 2
- PublicationAccès libreEin nachhaltiges Supply Chain Bewertungsmodell unter besonderer Berücksichtigung zeitlicher Wettbewerbsfaktoren(2012)
That is why a sustainable supply chain evaluation model is developed in this dissertation, which, above all, takes time-based competition factors into account. The evaluation model provides an attempt of how to better understand, analyze and evaluate the overall performance of lead time reduction methods or, in general, the lead time. The benefit is illustrated based on the application for a real supply chain with subsequent implementation. All in all, the dissertation adds to a better understanding of relations within the supply chain.
The dissertation is structured as follows in order to reach the research objective:
First of all, theoretical basics are described and methodic outlook is provided which reflects the research attempt.
This is followed by an empirical examination of the queueing theory in chapter 3. It’s most important theoretical basis for production management is the functional correlation of resource utilization, variability and lead time. Even if there is no doubt about the correctness of axiomatic, quantitative research, the exponential proportion between lead time and resource utilization has so far not been examined explicitly based on empirical data of complex production systems. Varied reasons might be stated for this loophole. For example, companies make implied efforts to avoid an increase in lead time in situation of high resource utilization. It must be checked in particular against the background of real implementation to which extent the theoretical basics can be found in practical application. A global leading polymer-processing company will be selected in order to answer the research question in an empirical manner. This branch of industry is marked by high customer requirements. This becomes apparent above all from very short lead times, a high level of response to new market trends and a high level of quality. The proportion between lead time and resource utilization will be examined based on more than 19,000 products over a period of 2 1/2 years.
Afterwards, a sustainable supply chain evaluation model is developed in chapter 4, which, above all, takes time-based competitive factors into account. This is necessary since the maxim regarding an increase in resource utilization continues to be a widespread target for many managers in the manufacturing industry and in the service sector. This is due to inappropriate performance evaluation and incentive systems for managers in which dynamic correlations between production, customer and cost-oriented performance dimensions are neglected. An evaluation model is therefore created which takes account of dynamic correlations and which makes it possible to evaluate various lead time reduction attempts as a whole prior to implementation or in general. The combination of rapid modelling and system dynamics is the core element of the evaluation model. The necessary empirical data are provided by the aforementioned leading polymer-processing company which turned out to be an ideal object of investigation since evidence for the correlation between resource utilization and lead time could be provided in an empirical manner. In addition, an extensive data basis is available and, on the other hand, time-based competitive factors become more and more important in this branch of industry.
The evaluation model allows to examine and to evaluate the impact of lead time on the overall performance for many situations. The findings gained from this can now be used for supply chain processes (chapter 5). Cross-organizational as well as internal key performance indicators are measured by means of process simulation in order to evaluate strategic/tactical attempts for improvement of a specific supply chain. The adapted evaluation model is illustrated based on the polymer-processing company the supply chain of which is marked by an agile environment which means that the supply chain partners must be in a position to cope with fluctuating demand situations without jeopardizing the customer service level because it is the market winner. This is followed by the real implementation of the scenario with best results acc. to the simulation model.
Chapter 6 finally provides an overview of the results of the individual chapters. A conclusion is drawn and benefits of the dissertation are stated in this chapter as well. In addition, this chapter provides a perspective with regard to further potential research work. - PublicationAccès libreSupply chain performance: the impact of interactions between flexibility enablers and uncertainty(2011)
The impact of both uncertainty and flexibility on supply chain variability leads to multiple dynamic interactions, which creates complex problems at the time of assessing the impact of supply chain improvements on the performance of the system. Indeed, if general supply chain behavior has been identified, the impact of the interactions between specific operational settings on the system dynamics remains largely unknown. In particular, serious gaps remain in the understanding of the dependencies between flexibility enablers. This understanding is important because of its direct implications on the dynamic of the system. Interactions between flexibility enablers are assumed to influence the general ability of the system to demonstrate flexibility and therefore directly affect the behavior of the system. This knowledge is therefore required in order to better understand the mechanisms underlying supply chain performance, and then to enable model to capture better the dynamics of the systems.
The core of this dissertation is constituted by three articles that can be read separately. All of these studies are related to the interaction between uncertainty and flexibility with regard to supply chain performance; however, the detailed research questions considered in each study are distinct.
The first study investigates the interaction between forecasting and flexibility enablers with regard to managing demand. It is assumed that superior knowledge regarding demand influences the production process as well and, consequently, the flexibility enablers' effect on company performance. This analysis evidences that the impact of forecasting on performance is due to the mediating effect of flexibility enablers. In particular, it shows that the relationship between forecasting and customer satisfaction is mainly due to process flow management, while the relationship with cost efficiency is mainly due to layout. Therefore, this study not only provided evidence of the existing relationships between forecasting and performance, but it provided as well some insights on the causality of this relationship. In particular, the study showed that the availability of additional information helps the actors involved in a specific process to make prompt decisions and align different units that manage each separate part of the production process. The performance improvements (i.e., increased cost efficiency as well as effectiveness) related to improved forecasting can then be magnified by process or layout modifications.
The second study examines the real-life situation of a supply chain where the flexibility of the production facility is directly influenced by the level of uncertainty in demand. In this setting, better demand information (i.e., uncertainty reduction) allows for wiser decision making regarding capacity adjustments and reduces the trade-off between volume flexibility and production efficiency. The simulation results shows that, for the specific settings of the study, the benefits from the uncertainty reduction provided by advance demand information are strongly influenced by the production and inventory management constraints engaged in the supply network. In particular, the value of advance demand information is magnified by the realistic situation where uncertainty reduction enables the manufacturer to improve the alignment of its production capacity with the forthcoming demand. Also, the value of the advance demand information is dependent on the policy regulating the interaction between the distribution center and the manufacturer. These interactions combine to determine the ability of the supply chain to satisfy demand in an effective and efficient manner and are therefore of critical importance to support decision making.
The third study considers the implications of integrating the non-constant variability of the demand variance with periodic reviews of up-to-level inventory policy. Such variability is traditionally observed in seasonal demand patterns where the demand variance is generally correlated to the average demand. This research work demonstrates the potential trade-off existing between safety stock accuracy and safety stock variability in inventory control with seasonal demand. Specifically, it highlights how the improvement achieved in adapting the safety stock to the fluctuation of the variability of the perceived uncertainty (i.e., the non-constant variability of the forecast error) is balanced by the resulting increase in replenishment order variability. Further, this study demonstrates that this dynamic dependency can only be captured if the relationship between the capacitated production system and the inventory system is explicitly modeled (i.e., the lead time is endogenous).
In general, the above-mentioned contributions highlight the need for a better understanding of the relationships between uncertainty, flexibility, and performance at the supply chain level, integrating in the performance measurement both efficiency and effectiveness. Further, it provides evidence that valuable estimation of performance based on supply chain modeling requires integrating the detailed interaction existing between the specific operational characteristics of the network under study. From a managerial point of view, these findings stressed the danger inherent to decision making supported by over-simplified supply chain models and propose, through an example, a methodology to tackle this issue.