As grid computing scales up in size and diversity, anonymous communications will be desirable, and sometimes vital, for certain applications. However, existing anonymity protocols, when being applied to grid applicati...
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ISBN:
(纸本)0769522564
As grid computing scales up in size and diversity, anonymous communications will be desirable, and sometimes vital, for certain applications. However, existing anonymity protocols, when being applied to grid applications, either dramatically degrade system efficiency or cause severe performance bottlenecks. We found that a distributed and highly efficient anonymity protocol can be designed if one considers the existing trust in grids. We have designed such a protocol based on controlled anonymity, which maintains an entity's anonymity against untrustable entities. To our best knowledge, this protocol is the first one of its kind. Using the existing methods from anonymity studies, we quantitatively analyze the degree of anonymity that could be offered by this protocol, and use a simulator to confirm its efficiency advantage over the existing protocols.
In this paper methods for both speeding up passage processing and examining more passages using parallel computers are explored. The number of passages processed are varied in order to examine the effect on retrieval ...
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In this paper methods for both speeding up passage processing and examining more passages using parallel computers are explored. The number of passages processed are varied in order to examine the effect on retrieval effectiveness and efficiency. The particular algorithm applied has previously been used to good effect in Okapi experiments at TREC. This algorithm and the mechanism for applying parallel computing to speed up processing are described.
We determine the weakest failure detectors to solve several fundamental problems in distributed message-passing systems, for all environments - i.e., regardless of the number and timing of crashes. The problems that w...
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ISBN:
(纸本)9781581138023
We determine the weakest failure detectors to solve several fundamental problems in distributed message-passing systems, for all environments - i.e., regardless of the number and timing of crashes. The problems that we consider are: implementing an atomic register, solving consensus, solving quittable consensus (a variant of consensus in which processes have the option to decide 'quit' if a failure occurs), and solving non-blocking atomic commit.
This research's primary contribution is providing a relatively straightforward, sustainable infrastructure for integrating documents and services. Users see a totally integrated environment. The integration infras...
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ISBN:
(纸本)1581139381
This research's primary contribution is providing a relatively straightforward, sustainable infrastructure for integrating documents and services. Users see a totally integrated environment. The integration infrastructure generates supplemental link anchors. Selecting one generates a list of relevant links automatically through the use of relationship rules.
Questions and answers about the great principles framework for computing and its impact on the organization and content of curriculum, with special attention to communicating our field, teaching programming, and appea...
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ISBN:
(纸本)1581137982
Questions and answers about the great principles framework for computing and its impact on the organization and content of curriculum, with special attention to communicating our field, teaching programming, and appealing to a diverse audience.
The traditional model of market equilibrium supports impressive existence results, including the celebrated Arrow-Debreu Theorem. However, in this model, polynomial time algorithms for computing (or approximating) equ...
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The traditional model of market equilibrium supports impressive existence results, including the celebrated Arrow-Debreu Theorem. However, in this model, polynomial time algorithms for computing (or approximating) equilibria are known only for linear utility functions. We present a new, and natural, model of market equilibrium that not only admits existence and uniqueness results paralleling those for the traditional model but is also amenable to efficient algorithms.
Separation of concerns in existing code can be achieved by specific refactoring techniques. Modern refactoring tools support a number of well-known refactoring transformations, including method extraction. In this pap...
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ISBN:
(纸本)1581138423
Separation of concerns in existing code can be achieved by specific refactoring techniques. Modern refactoring tools support a number of well-known refactoring transformations, including method extraction. In this paper, we examine how method extraction can be improved through program slicing. Furthermore, we show how a generalization of such slice extraction can be applied to untangle existing code by extracting aspects. Copyright 2004acm.
Real time tissue deformation is an important aspect of interactive virtual reality (VR) environments such as medical trainers. Most approaches in deformable modelling use a fixed space discretization. A surgical train...
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ISBN:
(纸本)9781581139075
Real time tissue deformation is an important aspect of interactive virtual reality (VR) environments such as medical trainers. Most approaches in deformable modelling use a fixed space discretization. A surgical trainer requires high plausibility of the deformations especially in the area close to the instrument. As the area of intervention is not known a priori, adaptive techniques have to be applied. We present an approach for real time deformation of soft tissue based on a regular FEM mesh of cube elements as opposed to a mesh of tetrahedral elements used by the majority of soft tissue simulators. A regular mesh structure simplifies the local refinement operation as the elements topology and stiffness are known implicitly. We propose an octree-based adaptive multiresolution extension of our basic approach. The volumetric representation of the deformed object is created automatically from medical images or by voxelization of a surface model. The resolution of the volumetric representation is independent of the surface geometry resolution. The surface is deformed according to the simulation performed on the underlying volumetric mesh. Copyright 2004acm.
This paper outlines two methods of computing irredundant irreducible decompositions of large scale monomial ideals with tens of thousands of minimal generators. Accomplishing this task is infeasible in current availab...
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ISBN:
(纸本)9781581138276
This paper outlines two methods of computing irredundant irreducible decompositions of large scale monomial ideals with tens of thousands of minimal generators. Accomplishing this task is infeasible in current available software given the algorithms they use. In contrast, an implementation was built using the methods in this paper. This implementation was able to compute large decompositions as well as other currently infeasible computations. Copyright 2004acm.
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