3,320 research outputs found

    Minimizing Maximum Flow Time on Related Machines via Dynamic Posted Pricing

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    We consider a setting where selfish agents want to schedule jobs on related machines. The agent submitting a job picks a server that minimizes a linear combination of the server price and the resulting response time for that job on the selected server. The manager\u27s task is to maintain server prices to (approximately) optimize the maximum response time, which is a measure of social good. We show that the existence of a pricing scheme with certain competitiveness is equivalent to the existence of a monotone immediate-dispatch algorithm. Our main result is a monotone immediate-dispatch algorithm that is O(1)-competitive with respect to the maximum response time

    Online Non-Preemptive Scheduling to Minimize Maximum Weighted Flow-Time on Related Machines

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    We consider the problem of scheduling jobs to minimize the maximum weighted flow-time on a set of related machines. When jobs can be preempted this problem is well-understood; for example, there exists a constant competitive algorithm using speed augmentation. When jobs must be scheduled non-preemptively, only hardness results are known. In this paper, we present the first online guarantees for the non-preemptive variant. We present the first constant competitive algorithm for minimizing the maximum weighted flow-time on related machines by relaxing the problem and assuming that the online algorithm can reject a small fraction of the total weight of jobs. This is essentially the best result possible given the strong lower bounds on the non-preemptive problem without rejection

    An O(log⁥n)O(\log n)-Competitive Posted-Price Algorithm for Online Matching on the Line

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    Motivated by demand-responsive parking pricing systems, we consider posted-price algorithms for the online metric matching problem. We give an O(log⁥n)O(\log n)-competitive posted-price randomized algorithm in the case that the metric space is a line. In particular, in this setting we show how to implement the ubiquitous guess-and-double technique using prices

    Dynamic pricing of servers on trees

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    In this paper we consider the k-server problem where events are generated by selfish agents, known as the selfish k-server problem. In this setting, there is a set of k servers located in some metric space. Selfish agents arrive in an online fashion, each has a request located on some point in the metric space, and seeks to serve his request with the server of minimum distance to the request. If agents choose to serve their request with the nearest server, this mimics the greedy algorithm which has an unbounded competitive ratio. We propose an algorithm that associates a surcharge with each server independently of the agent to arrive (and therefore, yields a truthful online mechanism). An agent chooses to serve his request with the server that minimizes the distance to the request plus the associated surcharge to the server. This paper extends [9], which gave an optimal k-competitive dynamic pricing scheme for the selfish k-server problem on the line. We give a k-competitive dynamic pricing algorithm for the selfish k-server problem on tree metric spaces, which matches the optimal online (non truthful) algorithm. We show that an α-competitive dynamic pricing scheme exists on the tree if and only if there exists α-competitive online algorithm on the tree that is lazy and monotone. Given this characterization, the main technical difficulty is coming up with such an online algorithm

    Processing Data-Intensive Workflows in the Cloud

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    In the recent years, large-scale data analysis has become critical to the success of modern enterprise. Meanwhile, with the emergence of cloud computing, companies are attracted to move their data analytics tasks to the cloud due to its exible, on demand resources usage and pay-as-you-go pricing model. MapReduce has been widely recognized as an important tool for performing large-scale data analysis in the cloud. It provides a simple and fault-tolerance framework for users to process data-intensive analytics tasks in parallel across dierent physical machines. In this report, we survey alternative implementations of MapReduce, contrasting batched-oriented and pipelined execution models and study how these models impact response times, completion time and robustness. Next, we present three optimization strategies for MapReduce-style work- ows, including (1) scan sharing across MapReduce programs, (2) work- ow optimizations aimed at reducing intermediate data, and (3) schedul- ing policies that map work ow tasks to dierent machines in order to minimize completion times and monetary costs. We conclude with a brief comparison across these optimization strate- gies, and discuss their pros/cons as well as performance implications of using more than one optimization strategy at a time.University of Pennsylvania Department of Computer and Information Science Technical Report No. MS-CIS-12-07

    Energy-aware coordination of machine scheduling and support device recharging in production systems

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    Electricity generation from renewable energy sources is crucial for achieving climate targets, including greenhouse gas neutrality. Germany has made significant progress in increasing renewable energy generation. However, feed-in management actions have led to losses of renewable electricity in the past years, primarily from wind energy. These actions aim to maintain grid stability but result in excess renewable energy that goes unused. The lost electricity could have powered a multitude of households and saved CO2 emissions. Moreover, feed-in management actions incurred compensation claims of around 807 million Euros in 2021. Wind-abundant regions like Schleswig-Holstein are particularly affected by these actions, resulting in substantial losses of renewable electricity production. Expanding the power grid infrastructure is a costly and time-consuming solution to avoid feed-in management actions. An alternative approach is to increase local electricity consumption during peak renewable generation periods, which can help balance electricity supply and demand and reduce feed-in management actions. The dissertation focuses on energy-aware manufacturing decision-making, exploring ways to counteract feed-in management actions by increasing local industrial consumption during renewable generation peaks. The research proposes to guide production management decisions, synchronizing a company's energy consumption profile with renewable energy availability for more environmentally friendly production and improved grid stability

    A Case for Cooperative and Incentive-Based Coupling of Distributed Clusters

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    Research interest in Grid computing has grown significantly over the past five years. Management of distributed resources is one of the key issues in Grid computing. Central to management of resources is the effectiveness of resource allocation as it determines the overall utility of the system. The current approaches to superscheduling in a grid environment are non-coordinated since application level schedulers or brokers make scheduling decisions independently of the others in the system. Clearly, this can exacerbate the load sharing and utilization problems of distributed resources due to suboptimal schedules that are likely to occur. To overcome these limitations, we propose a mechanism for coordinated sharing of distributed clusters based on computational economy. The resulting environment, called \emph{Grid-Federation}, allows the transparent use of resources from the federation when local resources are insufficient to meet its users' requirements. The use of computational economy methodology in coordinating resource allocation not only facilitates the QoS based scheduling, but also enhances utility delivered by resources.Comment: 22 pages, extended version of the conference paper published at IEEE Cluster'05, Boston, M
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