Topic
Service level
About: Service level is a research topic. Over the lifetime, 7647 publications have been published within this topic receiving 126093 citations. The topic is also known as: service level.
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TL;DR: In this article, a three-tiered hierarchical model based on a fixed cycle times policy is presented, which gives insight into the influence that the demand manager has upon the results in the production department.
Abstract: In a changing and more dynamic market of the 1980s, available mathematical programming algorithms on which production planning in process industries was based did not provide the required responsiveness. Although it is suggested in the literature that a variable cycle times policy will enable the system to react to short‐term demand fluctuations, proposes the use of a fixed cycle times policy. Presents simulation results which show a considerable improvement in service level at a high level of utilization. Presents a three‐tiered hierarchical model which is based on this fixed cycle times policy, which gives insight into the influence that the demand manager has upon the results in the production department. On the other hand, it also reflects the commercial interests. Suggests that for both departments which are this strongly intertwined, a common reference is necessary to improve the general results of the business.
44 citations
11 Jun 2007
TL;DR: This work will demonstrate how NIMO learns performance models in an online and automatic fashion using active learning and uses these models to do automated and on-demand provisioning of VMs in Shirako for two classes of database applications - multi-tier web services and computational science workflows.
Abstract: Utility computing delivers compute and storage resources to applications as an 'on-demand utility', much like electricity, from a distributed collection of computing resources. There is great interest in running database applications on utility resources (e.g., Oracle's Grid initiative) due to reduced infrastructure and management costs, higher resource utilization, and the ability to handle sudden load surges. Virtual Machine (VM) technology offers powerful mechanisms to manage a utility resource infrastructure. However, provisioning VMs for applications to meet system performance goals, e.g., to meet service level agreements (SLAs), is an open problem. We are building two systems at Duke - Shirako and NIMO - that collectively address this problem. Shirako is a toolkit for leasing VMs to an application from a utility resource infrastructure. NIMO learns application performance models using novel techniques based on active learning, and uses these models to guide VM provisioning in Shirako. We will demonstrate: (a) how NIMO learns performance models in an online and automatic fashion using active learning; and (b) how NIMO uses these models to do automated and on-demand provisioning of VMs in Shirako for two classes of database applications - multi-tier web services and computational science workflows.
44 citations
08 Jun 2015
TL;DR: It is argued that the introduction of Experience Level Agreements (ELA) as QoE-enabled counterpiece to traditional QoS-based Service Level Agreement (SLA) would provide a key step towards being able to sell service quality to the user.
Abstract: In contrast to the rather network-centric notion of Quality of Service (QoS), the concept of Quality of Experience (QoE) has a strongly user-centric perspective on service quality in communication networks as well as online services. However, related research on QoE so far has largely neglected the question of how to operationalize quality differentiation and to provide corresponding solutions tailored to the end users. In this paper, we argue that the introduction of Experience Level Agreements (ELA) as QoE-enabled counterpiece to traditional QoS-based Service Level Agreements (SLA) would provide a key step towards being able to sell service quality to the user. Hence, we investigate various ideas to exploit QoE awareness for improving SLAs (ranging from internal aspects like SLOs by service providers to completely novel definitions of ELAs which are able to characterize QoE explicitly), and discuss important problems and challenges of the proposed transition as well.
44 citations
TL;DR: This work separates the agreement's fault-tolerance concerns and strategies into multiple autonomous layers that can be hierarchically combined into an intuitive, parallelized, effective and efficient management structure for the automated management of the complete SLA lifecycle.
44 citations
TL;DR: An integrated approach for reserving inventory in anticipation of future order arrivals from high priority customers and for order promising in real-time is developed and an algorithm that exploits the time structure in order arrivals and time-phased material receipts to determine inventory reservations for high priority orders is proposed.
Abstract: In this paper we consider a Make-to-Stock order fulfillment system facing random demand with random due date preferences from two classes of customers. We develop an integrated approach for reserving inventory in anticipation of future order arrivals from high priority customers and for order promising in real-time. Our research exhibits three distinct features: (1) we explicitly model uncertain due date preferences of the customers; (2) we consider multiple receipts in the planning horizon that can be utilized to fulfill customer orders; and (3) we choose to utilize a service level measure for reserving inventory rather than estimating short- and long-term implications of order promising with a penalty cost function. We propose an algorithm that exploits the time structure in order arrivals and time-phased material receipts to determine inventory reservations for high priority orders. Numerical experiments are conducted to investigate the performance and the benefits of the inventory reservation and order promising approach under varying system parameters.
44 citations