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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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Patent
26 Apr 2002
TL;DR: In this paper, an end-to-end content management and delivery architecture is presented, which provided for end to end content management from a data storage facility to an requestor (5) remotely located.
Abstract: An end-to-end content management and delivery architecture is disclosed which provided for end-to-end content management from a data storage facility to an requestor (5) remotely located. An End-to-End Content I/O Management (ECIM) contains a Global Infrastructure Control (GIC) (4) that monitors the composite load levels at data centers (1, 2, and 3) across network servers, and identifies the best data center from which content request is met. Each data center has a QoS enforcer that monitors content arriving at the data center and controls the entry of all traffic at the data center. Each data center also has a controller, which controls the end-to-end I/O in the local data center. The ECIM allows end-to-end control of the content delivery, scalability provisioning of the application content storage pool to meet service level agreements; dynamic load balancing of the content, and optimization of the I/O resources both locally and across data centers (1, 2, and 3) so as to maximize the service level guarantees with minimum resource usage from application servers to storage.

251 citations

Journal ArticleDOI
TL;DR: The implementation of Optimizer has made it possible to make strategic changes to the configuration and control of the parts distribution network and has proven to be a highly flexible planning and operational control system.
Abstract: IBM recently implemented Optimizer, a system for flexible and optimal control of service levels and spare parts inventory, in its US network for service support. It is based upon recent research in multi-echelon inventory theory to address the IBM network. The inherent complexity and very large scale of the basic problem required IBM to develop suitable algorithms and sophisticated data structures and required large-scale systems integration. Optimizer has greatly improved IBM's US service business. The implementation of Optimizer has made it possible to make strategic changes to the configuration and control of the parts distribution network. It resulted in simultaneously reducing inventory investment and operating costs and improving service levels. Most important, however, Optimizer has proven to be a highly flexible planning and operational control system.

251 citations

Book ChapterDOI
TL;DR: This paper analyzed how the costs of providing waste removal service vary systematically with the identity of the collector, the degree of competition, and the size of the market served, and developed a theoretical model to analyze the interrelated impact of scale and market structure on cost.
Abstract: HOUSEHOLD refuse may be collected by public agencies or private firms operating in areas of spatial monopoly or not and subject to considerable or little government regulation. These characteristics define the form and scale of the market structure for refuse collection. This paper analyzes how the costs of providing waste removal service vary systematically with the identity of the collector, the degree of competition, and the size of the market served. Early studies of refuse collection either did not address the impact of market structure on costs or neglected to define clearly the service being provided. A major conclusion of these studies is that a higher level of service (i.e., more frequent collection, pickup location more distant from the curb) is more costly than a lower level of service (Hirsch, 1965; Clark et al. 1971; Partridge, 1974).' More recent studies have shed some light on the interrelationships of scale, market structure and costs, but the evidence so far has been scattered. Young (1972) presented an argument for the existence of some scale economies and for the greater efficiency of the private than of the public collector of refuse, but no empirical tests of these hypotheses were offered. In the one preceding study that investigated the presence of scale economies in refuse collection, estimates did not hold the service level constant (McFarland et al., 1972). Although some scale economies were found, these results may be misleading if small markets tend to demand a higher (and thus more costly) level of service than do large markets. A recent study of a small group of cities in Connecticut (Kemper a d Quigley, 1976) investigated the impact of market structure on costs, holding service level constant, but was unable, due to limitations of the data, to incorporate a consideration of scale nto the analysis. Although private firms were found to collect refuse at lower costs than public agencies, the findings may be spurious if private firms tend to serve larger markets (perhaps encompassing several cities and towns) than do public agencies, or, alternatively, the findings may be an outgrowth of specific regional or local conditions. The remainder of this paper attempts to remedy some of the omissions of preceding studies. The next section defines three distinct market structures, each of which is frequently observed in the real world, and develops a theoretical model to analyze the interrelated impact of scale and market structure on cost. Following this, equations derived from the theoretical framework are estimated and the results are presented. Equations are estimated using a nation-wide data base holding scale and service level effects constant.2 The final section contains policy guidelines and conclusions arising directly from the empirical work.

246 citations

Journal ArticleDOI
TL;DR: An ambulance location optimization model that minimizes the number of ambulances needed to provide a specified service level and considers response time to be composed of a random delay (prior to travel to the scene) plus a random travel time is described.
Abstract: We describe an ambulance location optimization model that minimizes the number of ambulances needed to provide a specified service level. The model measures service level as the fraction of calls reached within a given time standard and considers response time to be composed of a random delay (prior to travel to the scene) plus a random travel time. In addition to modeling the uncertainty in the delay and in the travel time, we incorporate uncertainty in the ambulance availability in determining the response time. Models that do not account for the uncertainty in all three of these components may overestimate the possible service level for a given number of ambulances and underestimate the number of ambulances needed to provide a specified service level. By explicitly modeling the randomness in the ambulance availability and in the delays and the travel times, we arrive at a more realistic ambulance location model. Our model is tractable enough to be solved with general-purpose optimization solvers for cities with populations around one Million. We illustrate the use of the model using actual data from Edmonton.

245 citations

Journal ArticleDOI
TL;DR: A large-scale field test confirms that the adverse impact of a stockout extends to both other items in the current order as well as future orders and investigates the effectiveness of different responses that firms can offer to mitigate the cost of stockouts.
Abstract: There is now an extensive theoretical literature investigating optimal inventory policies for retailers. Yet several recent reviews have recognized that these models are rarely applied in practice. One explanation for the paucity of practical applications is the difficulty of measuring how stockouts affect both current and future demand. In this paper, we report the findings of a large-scale field test that measures the short- and long-run opportunity cost of a stockout. The findings confirm that the adverse impact of a stockout extends to both other items in the current order as well as future orders. We show how the findings can be used to provide input to inventory planning models and illustrate how failing to account for the long-run effects of a stockout will lead to suboptimal inventory decisions. We also demonstrate how the findings can be used in a customer lifetime value model. Finally, the study investigates the effectiveness of different responses that firms can offer to mitigate the cost of stockouts. There is considerable variation in the effectiveness of these responses. Offering discounts to encourage customers to backorder rather than cancel their orders is widely used in practice, but that was the least profitable of the responses that we evaluated. The findings have important implications for retailers considering the use of discounts as a response to stockouts.

241 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202321
202257
2021257
2020350
2019413
2018415