ppxscal/embedding_network huggingface dataset:
Deciding When to Forget in the Elephant File System
Authors: Douglas S. Santry, Michael J. Feeley, Norman Hutchinson, Alistair C. Veitch, Ross W. Carton, Jacob Ofir
Venue:  (1999)

Modern file systems associate the deletion of a file with the immediate release of storage, and file writes with the irrevocable change of file contents. We argue that this behavior is a relic of the past, when disk storage was a scarce resource. Today, large cheap disks make it possible for the file system to protect valuable data from accidental delete or overwrite. This paper describes the design, implementation, and performance of the Elephant file system, which automatically retains all important versions of user files. Users name previous file versions by combining a traditional pathname with a time when the desired version of a file or directory existed. Storage in Elephant is managed by the system using file-grain user-specified retention policies. This approach contrasts with checkpointing file systems such as Plan-9, AFS, and WAFL that periodically generate efficient checkpoints of entire file systems and thus restrict retention to be guided by a single policy for all files within that file system. Elephant is implemented as a new Virtual File System in the FreeBSD kernel.
Motivation fur Datenreplikation im Netzwerkmanagment
Authors: S. Geschke
Venue:  (1996)

Es werden Voraussetzungen und Losungsansatze vorgestellt, um Daten redundant im Netzwerkmanagement zu verwalten. Die Bewertung der Replikationsstrategien erfolgt mit Hilfe der Datencharakteristik und -verteilung, der Konsistenzsicherung sowie anhand der Auswirkungen auf die Managementumgebung. Ein Ausblick auf alternative Anwendungsbereiche der Verteilungskonzepte rundet die Betrachtungen ab. The ACM Portal is published by the Association for Computing Machinery. Copyright © 2010 ACM, Inc. Terms of Usage Privacy Policy Code of Ethics Contact Us Useful downloads: Adobe Acrobat QuickTime Windows Media Player Real Player
SAMPLE COMPRESSION, LEARNABILITY, AND THE VAPNIK-CHERVONENKIS DIMENSION
Authors: Sally Floyd, Manfred Warmuth
Venue:  (1993)

Within the framework of pac-learning, we explore the learnability of concepts from samples using the paradigm of sample compression schemes. A concept is a subset of some instance domain X and a concept class a set of concepts. A sample compression scheme of size d for a concept class C consists of a compression function and a reconstruction function. The compression function, given a finite sample set consistent with some concept in C, chooses a subset of k examples as the compression set. The reconstruction function, given a compression set of k examples, reconstructs a hypothesis on X. Given a compression set produced by the compression function from a sample of a concept in C, the reconstruction function must be able to reproduce a hypothesis consistent with that sample. We demonstrate that the existence of a fixed-size sample compression scheme for a class C is sufficient to ensure that the class C is learnable. We define maximum and maximal classes of VC dimension d. For every maximum class of VC dimension d, there is a sample compression scheme of size d, and for sufficiently-large maximum classes there is no sample compression scheme of size less than d. We discuss briefly classes of VC dimension d that applies to some maximal and nonmaximum classes. It is unknown whether there is a sample compression scheme of size d for every class of VC dimension d.
Homogenization method in Stochastic Finite Element analysis of some 1D composite structures
Authors: M. Kamiński
Venue: Proceedings of the eighth international conference on The application of artificial intelligence to civil and structural engineering computing (2001)

The main idea is to present the application of the homogenization method in the Stochastic Finite Element Method (SFEM) of some 1D linear elastic engineering structures. The method is based on the second order perturbation second central probabilistic moment analysis and, on other hand, asymptotic calculation of the probabilistic moments of the effective Young modulus. This approach is used together with the classical SFEM computer program and illustrated on the examples of the two-component beam and bar structures. The results of numerical analysis confirm generally the usefulness of the proposed method to homogenization-based analysis of the bar structures with randomly defined material parameters. Starting from this formulation, the deterministic as well as stochastic sensitivity analysis of the homogenized composite structures may be performed and, further, homogenization approach for stochastic analysis of elastodynamic problems with or without structural and interface defects may be proposed.
Finite element analyses of steel beam to concrete-filled circular steel tube column connections
Authors: C. C. Chen, H. L. Li
Venue: Proceedings of the eighth international conference on The application of artificial intelligence to civil and structural engineering computing (2001)

This paper presents the analytical investigation of behaviour of connections between steel beam and concrete-filled circular steel tube column. Finite element analyses were conducted to investigate the force transfer mechanism of various configurations of connection details. Good agreement between experimental and analytical results is obtained. The connection of beam directly welded to the steel tube cannot develop the required flexural strength due to the distortion of the tube wall. Both external diaphragm and side plate reinforced connections possess the sufficient flexural strength since the beam flange forces can be effectively transferred to and resisted by the concrete core inside the steel tube.
Enumeration and Analysis of Variable Geometry Truss Manipulators
Authors: V. A Reinholtz, Layne T. Watson
Venue:  (1990)

The variable-geometry truss or VGT, is a generalization of Stewart''s most basic platform manipulator concept. In this paper, all possible basic forms of the truss-type manipulator are enumerated. These basic forms, or unit cells, are shown to be building blocks from which all truss-type manipulators are formed. Several manipulator concepts based on the unit cell construction are then presented as examples, including a new potentially superior form of Stewart''s Platform. Finally, a general method for the forward kinematic analysis of VGT unit cells is described.
PRAM Implementation on Fine-Grained MIMD Multicomputers
Authors: Francoise Baude
Venue:  (1992)

The more user-friendly tools for expressing data-parallelism are encompassed by the PRAM language mechanisms (mainly, global addressing space, implicit processes synchronization). In this paper, we evaluate the cost for implementing such mechanisms on the only class of parallel architectures that should prove to be really scalable as well as versatile, i.e. MIMD fine-grained multicomputers. Being massively parallel, these architectures are constrained to not exceed a given wire density and also to have fine-grained processing nodes. For these reasons, recent algorithmic and hardware technics for hidding communication latency of PRAM emulations by parallel slackness do not apply. We consider an abstraction of these machines by reasoning in terms of the actor model of concurrent computation. Given the architectural constraints raised by the chosen class of architectures, the idea for implementing any PRAM program is to transform it into an actor program such that it can be efficiently implemented on the target machine via mapping technics such as for exemple graph embedding. This requires the underlying communication graph of the actor program to be predictable and sparse. This transformation is grounded on probabilistic theoretical simulations of PRAMs on parallel machines based on sparse communication networks.
The Boolean Functions Computed by Random Boolean Formulas OR How to Grow the Right Function
Authors: Alex Brodsky, Nicholas Pippenger
Venue:  (2003)

Among their many uses, growth processes (probabilistic amplification), were used for constructing reliable networks from unreliable components, and deriving complexity bounds of various classes of functions. Hence, determining the initial conditions for such processes is an important and challenging problem. In this paper we characterize growth processes by their initial conditions and derive conditions under which results such as Valiant''s (Valiant, 1984) hold. First, we completely characterize growth processes that use linear connectives. Second, by extending Savick\''y''s (Savick\''y, 1990) analysis, via ``Restriction Lemmas'''', we characterize growth processes that use monotone connectives, and show that our technique is applicable to growth processes that use other connectives as well.
Multi-stage Cascaded Prediction
Authors: Karel Driesen, Urs Holzle
Venue:  (1999)

Two-level predictors deliver highly accurate conditional branch prediction, indirect branch target prediction and value prediction. Accurate prediction enables speculative execution of instructions, a technique that increases instruction level parallelism. Unfortunately, the accuracy of a two-level predictor is limited by the cost of the predictor table that stores associations between history patterns and target predictions. Two-stage cascaded prediction, a recently proposed hybrid prediction architecture, uses pattern filtering to reduce the cost of this table while preserving prediction accuracy. In this study we generalize two-stage prediction to multi-stage prediction. We first determine the limit of accuracy on an indirect branch trace using a multi-stage predictor with an unlimited hardware budget. We then investigate practical cascaded predictors with limited tables and a small number of stages. Compared to two-level prediction, multi-stage cascaded prediction delivers superior prediction accuracy for any given total table entry budget we considered. In particular, a 512-entry three-stage cascaded predictor reaches 92% accuracy, reducing table size by a factor of four compared to a two-level predictor. At 1.5K entries, a three-stage predictor reaches 94% accuracy, the hit rate of a hypothetical two-level predictor with an unlimited, fully associative predictor table. At 6K entries, accuracy increases to 95%, the limit achieved by an idealized twelve-stage cascaded predictor with an unlimited hardware budget. These results indicate that highly accurate indirect branch target prediction is now well within the capability of current hardware technology.
A Full Variational Calculation Based on a Tensor ProductDecomposition
Authors: Frederick A. Senese, Christopher A. Beattie, John C. Schug, Jimmy W. Viers, Layne T. Watson
Venue:  (1989)

A new direct full variational approach exploits a tensor (Kronecker) product decomposition of the Hamiltonian. Explicit assembly and storage of the Hamiltonian matrix is avoided by using the Kronecker product structure to form matrix-vector products directly from the molecular integrals. Computation-intensive integral transformations and formula tapes are unnecessary. The wavefunction is expanded in terms of spin-free primitive kets rather than Staler determinants of configuration state functions, and the expansion is equivalent to a full configuration interaction expansion. The approach suggests compact storage schemes and algorithms which are naturally suited to parallel and pipelined machines.
A Sequent System for Lewis''s Counterfactual Logic VC
Authors: Ian P. Gent
Venue:  (1990)

This report presents a technical result concerning practical proof systems for counterfactual (also known as conditional) logics. In a 1983 paper, HCM de Swart gave sequent based proof systems for two counterfactual logics: Stanlaker''s VCS and Lewis''s VC. In this report I demonstrate that de Swart''s system for VC is incorrect by giving a counterexample. This counterexample does not effect de Swart''s system for VCS. Then I give a new sequent based proof system for VC together with soundness and completeness proofs. The system I give is closely modelled on de Swart''s/
Coverage Analysis Methods for Formal Software Testing
Authors: John A. N. Lee, Xudong He
Venue:  (1987)

Software creation requires not only testing during the development cycle by the development staff, but also independent validation following the completion of the implementation. However in the latter case, the amount of testing that can be carried out is often limited by time and resources. At the very most, independent testing can be expected to provide 100% coverage of the requirements (or specifications) associated with the software element. This report describes a methodology by which the amount of testing required to provide 100% coverage of the requirements is assured while at the same time minimizing the total number of tests included in a test suite. A collateral procedure provides recommendations on which tests which might be eliminated if less than 10O% coverage of the requirements is permitted. This latter process will be useful in determining the risk of not running the minimum set of tests for 100% coverage. A second process selects from the test matrix the set of tests to be applied to the system following maintenance modification of any module-- that is, to provide a submatrix for regression testing.
Improved Approximation of Maximun Planar Subgraph
Authors: Alexander Zelikovsky
Venue:  (1996)

The maximum planar subgraph problem (MPSP) asks for a planar subgraph of a given graph with the maximum total cost. We suggest a new approximation algorithm for the weighted MPSP. We show that it has performance ratio of 5/12 in the case of graphs where the maxumum cost of an edge is at most twice the minimum cost of an edge. For the variant of MPSP that asks for an outerplanar graph, the algorithm suggested is the first with the higher performance ratio (7/12 instead of 1/2).
Relative Serializability: An Approach for Relaxing the Atomicity of Transactions
Authors: D. Agrawal, J. L. Bruno, A. E Abbadi, V. Krishnaswamy
Venue:  (1994)

In the presence of semantic information, serializability is too strong a correctness criterion and unnecessarily restricts concurrency. We use the semantic information of a transaction to provide different atomicity views of the transaction to other transactions. The proposed approach improves concurrency and allows interleavings among transactions which are non-serializable, but which nonetheless preserve the consistency of the database and are acceptable to the users. We develop a graph-based tool whose acyclicity is both a necessary and suffcient condition for the correctness of an execution. Our theory encompasses earlier proposals that incorporate semantic information of transactions. Furthermore it is the first approach that provides an effcient graph based tool for recognizing correct schedules without imposing any restrictions on the application domain. Our approach is widely applicable to many advanced database applications such as systems with long-lived transactions and collaborative environments.
Developing an Automated Procedure for Evaluating Software Development Methodologies and Associated Products
Authors: James D. Arthur, Richard E. Nance
Venue:  (1987)

Over the past decade the demand for increasingly complex software systems has risen dramatically [PARD 85]. Recognizing the fact that such systems cannot be developed effectively through ad hoc means, the software engineering community has continued to investigate the fundamental concepts, development methodologies, and automated tools to assist in the software development process. For example, SREM [ALFM 85] and SADT [SOFT 76, ROSD 77] are methodology based environments that focus on supporting particular phases of the software life cycle. SCR [CLEP 84, HENK 78] and DARTS [GOMH 84], on the other hand, are methodologies that emphasize specific goals, e .g ., reducing software development costs and designing real-time systems, respectively. This steady proliferation of design methodologies, however, is not without its price. In particular, users find increasing difficulty in choosing an appropriate methodological approach and recognizing reasonable expectations of a design or development methodology. These concerns motivated an initial research effort that led to a procedural approach for evaluating software development methodologies [ARTJ 86].
C1Modeling with Hybrid Multiple-sided A-patches
Authors: Guoliang Xu, Chandrajit L. Bajaj, Susan Evans
Venue:  (2001)

We propose a new scheme for modeling a smooth interpolatory surface, from a surface discretization consisting of triangles, quadrilaterals and pentagons, by algebraic surface patches which are subsets of real zero contours of trivariate rational functions defined on a collection of tetrahedra and pyramids. The rational form of the modeling function provides enough degrees of freedom so that the number of the surface patches is significantly reduced, and the surface has quadratic recover property.
Quantitative stiffness-based optimal design of tall buildings using a condensed lateral stiffness matrix
Authors: H. J. Lee, D. H. Lee, H. W. Lee, H. S. Kim
Venue: Proceedings of the eighth international conference on The application of artificial intelligence to civil and structural engineering computing (2001)

This study presents a quantitative drift control technique and an effective resizing technique for tall buildings under lateral drift constraints. To this end, this study first assembles the lateral stiffness matrix of the whole building and the lateral-stiffness influence matrix of each story, and then develops the technique to estimate the optimal lateral-stiffness increment factors satisfying the given drift constraints through the displacement sensitivity analysis for the lateral stiffness matrices. Also, resizing technique based on the estimated lateral-stiffness increment factors is developed, and then two types of 45-story three dimensional structures are presented to illustrate the features of the optimal design technique proposed in this study.
On Collocation Implementation for Singularly Perturbed Two-Point Problems
Authors: Uri Ascher, Simon Jacobs
Venue:  (1986)

We consider the numerical solution of singularly perturbed two-point boundary value problems in ordinary differential equations. Implementation methods for general purpose solvers of first order linear systems are examined, with the basic difference scheme being collocation at Gaussian points. Adaptive mesh selection is based on localized error estimates at the collocation points. These methods are implemented as modifications to the successful collocation code COLSYS, which was originally designed for mildly stiff problems only. Efficient high order approximations to extremely stiff problems are obtained, and comparisons to COLSYS show that the modifications work relatively much better as the singular perturbation parameter gets small (i.e. the problem gets stiff), for both boundary layer and turning point problems.
Docking topical hierarchies: A comparison of two algorithms for reconciling keyword structures
Authors: Bryan Tower, Mark Chaisson, Richard Belew
Venue:  (2001)

Hierarchies are a natural way for people to organize information, as reflected by the common use of ``broader/narrower'''' term relation in keyword thesauri. However, different people and organizations tend to construct different conceptual hierarchies (e.g., contrast Yahoo! with the UseNet news hierarchy), and while there are often significant commonalities it is in general quite difficult to fully reconcile them. We are particularly interested in the problem of ``docking'''' a narrower, more focused and refined topical hierarchy into a broader one, and describe two algorithms for accomplishing this task. The first matches hierarchies based on a bipartite matching algorithm of (textual) features of nodes without consideration of their hierarchic organization, and the second is based on an attributed tree matching algorithm which uses both hierarchic structure and node features. We present experimental results showing the performance of both algorithms on a set of very different topical hierarchies, all designed to represent the field of {\tt Computer\_Science}. These show that hierarchic structure does indeed allow more accurate matches than nodes alone.
Modelling of continuous slab-girder bridges for seismic analysis
Authors: S. Maleki
Venue: Proceedings of the eighth international conference on The application of artificial intelligence to civil and structural engineering computing (2001)

This paper is an analytical investigation of the effects of modeling assumptions for concrete decks of continuous slab-girder bridges subjected to earthquake forces. Rigid and flexible deck assumptions are compared for two- and three-span continuous bridges with varying span lengths and varying end cross-frame and pier stiffness. The effects of this assumption on transverse period of vibration, displacement demand, and force demand on supporting elements are investigated. Three-dimensional finite element analysis is used. It is shown that the assumption of rigid deck action for the deck simplifies the analysis and it is safe to use for all practical ranges of span and support stiffness.