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12
A Framework for Evaluating Replica Placement Algorithms
, 2002
"... This paper introduces a framework for evaluating replica placement algorithms (RPA) for content delivery networks (CDN) as well as RPAs from other fields that might be applicable to current or future CDNs. First, the framework classifies and qualitatively compares RPAs using a generic set of primiti ..."
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Cited by 42 (1 self)
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This paper introduces a framework for evaluating replica placement algorithms (RPA) for content delivery networks (CDN) as well as RPAs from other fields that might be applicable to current or future CDNs. First, the framework classifies and qualitatively compares RPAs using a generic set of primitives that capture problem definitions and heuristics. Second, it provides estimates for the decision times of RPAs using an analytic model. To achieve accuracy, the model takes into account disk accesses and message sizes, in addition to computational complexity and message numbers that have been considered traditionally. Third, it uses the "goodness" of produced placements to compare RPAs even when they have different problem definitions. Based on these evaluations, we identify open issues and potential areas for future research.
On the competitive ratio for online facility location
 In ICALP
, 2003
"... Abstract. We consider the problem of Online Facility Location, where demands arrive online and must be irrevocably assigned to an open facility upon arrival. The objective is to minimize the sum of facility and assignment costs. We prove that the competitive log n ratio for Online Facility Location ..."
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Cited by 21 (1 self)
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Abstract. We consider the problem of Online Facility Location, where demands arrive online and must be irrevocably assigned to an open facility upon arrival. The objective is to minimize the sum of facility and assignment costs. We prove that the competitive log n ratio for Online Facility Location is Θ (). On the negative side, we show that no log log n randomized algorithm can achieve a competitive ratio better than Ω ( ) against an log log n oblivious adversary even if the demands lie on a line segment. On the positive side, we present log n a deterministic algorithm achieving a competitive ratio of O (). The analysis is based log log n on a hierarchical decomposition of the optimal facility locations such that each component either is relatively wellseparated or has a relatively large diameter, and a potential function argument which distinguishes between the two kinds of components. 1
A Unified Framework for Evaluating Replica Placement Algorithms
, 2002
"... The placement of data to maximize the performance and minimize the cost of a computing system is an optimization problem that has been studied extensively in several fields, including distributed databases, storage systems and, more recently, content delivery networks. However, little has been done ..."
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Cited by 10 (0 self)
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The placement of data to maximize the performance and minimize the cost of a computing system is an optimization problem that has been studied extensively in several fields, including distributed databases, storage systems and, more recently, content delivery networks. However, little has been done to compare the various approaches and their applicability to different systems.
A.: New bounds for the controller problem
 DISC. Lecture Notes in Computer Science
, 2009
"... The (M,W)controller, originally studied by Afek, Awerbuch, Plotkin, and Saks, is a basic distributed tool that provides an abstraction for managing the consumption of a global resource in a distributed dynamic network. The input to the controller arrives online in the form of requests presented at ..."
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Cited by 7 (1 self)
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The (M,W)controller, originally studied by Afek, Awerbuch, Plotkin, and Saks, is a basic distributed tool that provides an abstraction for managing the consumption of a global resource in a distributed dynamic network. The input to the controller arrives online in the form of requests presented at arbitrary nodes. A request presented at node u corresponds to the “desire” of some entity to consume one unit of the global resource at u and the controller should handle this request within finite time by either granting it with a permit or denying it. Initially, M permits (corresponding to M units of the global resource) are stored at a designated root node. Throughout the execution permits can be transported from place to place along the network’s links so that they can be granted to requests presented at various nodes; when a permit is granted to some request, it is eliminated from the network. The fundamental rule of an (M,W)controller is that a request should not be denied unless it is certain that at least M −W permits are eventually granted. The most efficient (M,W)controller known to date has message complexity O(N log2N log MW+1), where N is the number of nodes that ever existed in the network (the dynamic network may undergo node insertions and deletions).
Dynamic page migration under brownian motion
 In Proc. of the European Conf. in Parallel Processing (EuroPar
, 2005
"... Abstract. We consider Dynamic Page Migration (DPM) problem, one of the fundamental subproblems of data management in dynamically changing networks. We investigate a hybrid scenario, where access patterns to the shared object are dictated by an adversary, and each processor performs a random walk in ..."
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Cited by 6 (4 self)
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Abstract. We consider Dynamic Page Migration (DPM) problem, one of the fundamental subproblems of data management in dynamically changing networks. We investigate a hybrid scenario, where access patterns to the shared object are dictated by an adversary, and each processor performs a random walk in X. We extend the previous results of [4]: we develop algorithms for the case where X is a ring, and prove that with high probability they achieve a competitive ratio of Õ(min { 4 √ D, n}), where D is the size of the shared object and n is the number of nodes in the network. These results hold also for any ddimensional torus or mesh with diameter at least ˜ Ω ( √ D). 1
Page migration in dynamic networks
, 2005
"... In the last couple of decades, network connected systems have gradually replaced centralized parallel computing machines. To provide smooth operation of network applications, the underlying system has to provide socalled basic services. One of the most crucial services is to provide a transparent a ..."
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Cited by 3 (1 self)
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In the last couple of decades, network connected systems have gradually replaced centralized parallel computing machines. To provide smooth operation of network applications, the underlying system has to provide socalled basic services. One of the most crucial services is to provide a transparent access to data like
Economically Viable Support for Internet Mobility
 in Proceedings of the International Congerence on Communications ICC
, 2011
"... Abstract—The support for mobility is a major requirement for the future Internet. Although several mobility solutions have been proposed, none of them has been largely deployed, mostly because they are not economically viable. We propose a business oriented mobility framework Mobility Support Servi ..."
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Abstract—The support for mobility is a major requirement for the future Internet. Although several mobility solutions have been proposed, none of them has been largely deployed, mostly because they are not economically viable. We propose a business oriented mobility framework Mobility Support Service (MSS) to be offered as a valueadded service to paying mobile customers. MSS uses Identifiers (IDs) to locate the nodes and network addresses as points of attachment for the nodes. MSS is a scalable distributed service. MSS does not require changes in existing network architecture nor services. We present two MSS distributing algorithms that enable tradeoffs among costs and QoS. We show by simulations the advantages of MSS compared to existing mobility solutions, especially regarding scalability and service delay. However the main advantage of MSS is that it can be realistically offered, because it is economically viable. I.
GAME THEORETICAL REPLICA PLACEMENT TECHNIQUES FOR LARGE
, 2007
"... I would like to express my deepest appreciation to my advisor, Prof. Ishfaq Ahmad for his invaluable guidance through these years at UT Arlington. Without his longterm encouragement, patience, understanding, and persistent support, this dissertation would not have been completed. I would also like ..."
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I would like to express my deepest appreciation to my advisor, Prof. Ishfaq Ahmad for his invaluable guidance through these years at UT Arlington. Without his longterm encouragement, patience, understanding, and persistent support, this dissertation would not have been completed. I would also like to appreciate the efforts of my doctoral dissertation committee members, Drs. Che, Cook, Kung, and Lei for their precious time in reviewing this dissertation and for their valuable suggestions. I am especially grateful to Profs. Cook and Shirazi (at the Washington State University) and Prof. Kreinovich (at UT ElPaso) for their encouragement and continued support even though they were tens of miles away – thank you. At UT Arlington the last couple of years were made pleasant by the occasional conversations with Drs. Huber and Zaruba and Mr. Levine. I have learnt so much from you, about life, about (ir)rational thinking and almost about everything else. I dedicate this dissertation, a halfdecade effort to my parents, who made every possible and impossible effort to ensure that there was no hindrance in what I liked to pursue for education. iii
Competitive Algorithms for Online Data Placement on Uncapacitated Uniform Network
"... Abstract—In this paper, we study the iterated problem of placing copies of data objects in a network of storage servers in order to serve request demands with minimal delay. We show how to compute the optimal sequence of decisions for two variants: in general, using dynamic programming algorithm, wh ..."
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Abstract—In this paper, we study the iterated problem of placing copies of data objects in a network of storage servers in order to serve request demands with minimal delay. We show how to compute the optimal sequence of decisions for two variants: in general, using dynamic programming algorithm, which requires exponential time, and for uncapacitated uniform network, which requires only polynomial time. For the latter case, we study online algorithms, which return new placement immediately after a new element of input sequence becomes available. We prove that the comeptitive ratio of the problem is bounded by 2. The paper is summarized with computational study, which compares the 2competitive online algorithm with dynamic programming. Online distributed storage management becomes increasingly important issue in largescale Internet applications due to the widespread of Content Devlivery Networks, as well as cloud computing and contentaware paradigms. Keywords—online algorithms; network algorithms; widearea networks. I.