ppxscal/embedding_network huggingface dataset:
NMFS: Network Multimedia File System Protocol
Authors: Sameer Patel, Ghaleb Abdulla, Marc Abrams, Edward A. Fox
Venue:  (1992)

We describe an on-going project to develop a Network Multimedia File System (NMFS) protocol. The protocol allows "transparent access of shared files across networks" as Sun''s NFS protocol does, but attempts to meet a real-time delivery schedule. NMFS is designed to provide ubiquitous service over networks both designed and not designed to carry multimedia traffic.
Chitra: Visual Analysis of Parallel and Distributed Programs in the Time, Event, and Frequency Domains
Authors: Marc Abrams, Naganand Doraswamy, Anup Mathur
Venue:  (1992)

Chitra analyzes a program execution sequence (PES) collected during execution of a program and produces a homogeneous, semi-Markov chain model fitting the PES. The PES represents the evolution of a program state vector in time. Therefore Chitra analyzes the time-dependent behavior of a program. The paper describes a set of transforms that map a PES to a simplified PES. Because the transforms are program-independent, Chitra can be used with any program. Chitra provides a visualization of PES''s and transforms, to allow a user visually to guide transform selection in an effort to generate a simple yet accurate semi-Markov chain model. The resultant chain can predict performance at program parameters different than those used in the input PES, and the chain structure can diagnose performance problems.
Efficient Implementation of FFT--Like Algorithms on MIMD Systems
Authors: Jungclaus,  N, Michael Nolle
Venue:  (1994)

In this paper we investigate parallel implementations of the well known two-dimensional Fast Fourier Transform (FFT) algorithm. The FFT may be taken as a key algorithm representing a wide class of algorithms used in image processing and pattern recognition that are realized with a similar algorithmic structure. Examples within this class include the fast Walsh transform, translation-invariant transforms for position invariant feature extraction in gray scale images, fast parallel sorting, etc. In this paper we emphasize the minimization of the communication between the processors of the parallel system for FFT-like Algorithms .
Parallel ELLPACK for Shared Memory Multiprocessors
Authors: Calvin J. Ribbens, George G. Pitts, Layne T. Watson
Venue:  (1992)

This paper describes a parallel version of ELLPACK for shared memory multiprocessors. ELLPACK is a system for numerically solving elliptic PDEs. It consists of a very high level language for defining PDE problems and selecting methods of solution, and a library of approximately fifty problem solving modules. Earlier work considered three discretization modules (five point star, hodie, and hermite collocation), two linear system solution modules (linpack spd band and jacobi cg), and a triple module (hodie fft) which includes both discretization and solution, all for rectangular domains and simple boundary conditions. Here we describe parallel versions of six additional modules (hermite collocation, hodie helmholtz, five point star, band ge, sor, symmetric sor cg) for general boundary conditions and domains, and discuss modifications to the ELLPACK preprocessor, the tool that translates an ELLPACK "program" into FORTRAN.
Fire performance of single leaf masonry walls
Authors: A. Nadjai, M. O'Gara, F. Ali
Venue: Proceedings of the eighth international conference on The application of artificial intelligence to civil and structural engineering computing (2001)

A finite element model called MasSET has been developed which is capable of predicting the structural behaviour of single leaf masonry walls subject to elevated temperatures. The analysis models a slice through the wall as a column strip in plane stress, and also includes material with geometric non-linearity. The model has been previously validated by comparison with experimental results [1] and is used in this paper to conduct a parametric study investigating the effects of slenderness ratio, load eccentricity and boundary conditions. The results of the investigation are presented by way of failure temperatures for each condition, and show conclusive findings to the effects of each parameter investigated.
Symplectic Integration of Constrained Hamiltonian Systems by Runge-Kutta Methods
Authors: Reich Sebastian
Venue:  (1993)

Recent work reported in the literature suggests that for the long--term integration of Hamiltonian dynamical systems one should use methods that preserve the symplectic structure of the flow. In this paper we investigate the symplecticity of numerical integrators for constrained Hamiltonian systems. In the first part of the paper we show that those implicit Runge--Kutta methods which result in symplectic integrators for unconstrained Hamiltonian systems can be directly applied to constrained Hamiltonian systems. The resulting discretization scheme is symplectic but does not, in general, preserve the constraints. In the second part of the paper we discuss partitioned Runge--Kutta methods. Again it turns out that those partitioned Runge--Kutta methods which are symplectic for unconstrained systems can be applied to constrained Hamiltonian systems. We show that, in contrast to implicit Runge--Kutta methods, the class of symplectic partitioned Runge--Kutta methods includes methods that also preserve the constraints. In the third part of the paper we discuss constrained Hamiltonian systems with separable Hamiltonian from a Lie algebraic point of view. This approach not only provides a different approach to the numercial integration of Hamiltonian systems but also allows for a straighforward backward error analysis. 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
Non-linear analysis of composite floor slabs with geometric orthotropy
Authors: B. A. Izzuddin, X. Y. Tao, A. Y. Elghazouli
Venue: Proceedings of the eighth international conference on The application of artificial intelligence to civil and structural engineering computing (2001)

This paper describes ongoing research concerned with the development of an advanced nonlinear structural analysis method for composite floor slabs. The main feature of such slabs is their geometric orthotropy, a feature which cannot be modelled with existing 2D shell finite elements. A new 2D flat shell element is therefore proposed, for which the conventional Reissner-Mindlin hypothesis is modified to capture more accurately the influence of geometric orthotropy. Rib freedoms are incorporated in the new element, which are additional to the conventional freedoms typically associated with shell elements. A new plasticity-based model is proposed for concrete, the aim being to achieve realistic simulations whilst overcoming numerical problems often associated with the nonlinear concrete response. Two examples are finally presented to illustrate the accuracy of the proposed finite element formulation and the importance of its various parameters.
Homotopy Methods for Solving the Optimal Projection Equations for the H2 Reduced Order Model Problem
Authors: Dragan Zigic, Layne T. Watson, Emmanuel G. Collins, Dennis S. Bernstein
Venue:  (1991)

The optimal projection approach to solving the H2 reduced order model problem produces two coupled, highly nonlinear matrix equations with rank conditions as constraints. Due to the resemblance of these equations to standard matrix Lyapunov equations, they are called modified Lyapunov equations. The algorithms proposed herein utilize probability-one homotopy theory as the main tool. It is shown that there is a family of systems (the homotopy) that make a continuous transformation from some initial system to the final system. With a carefully chosen initial problem a theorem guarantees that all the systems along the homotopy path will be asymptotically stable, controllable and observable. One method, which solves the equations in their original form, requires a decomposition of the projection matrix using the Drazin inverse of a matrix. It is shown that the appropriate inverse is a differentiable function. An effective algorithm for computing the derivative of the projection matrix that involves solving a set of Sylvester equations is given. Another class of methods considers the equations in a modified form, using a decomposition of the pseudogramians based on a contragredient transformation. Some freedom is left in making an exact match between the number of equations and the number of unknowns, thus effectively generating a family of methods.
Schema Versions and Dag Rearrangement Views in Object-oriented Databases
Authors: Hyoung Kim, Henry F. Korth
Venue:  (1988)

An important requirement of non-traditional database applications such as computer aided design, artificial intelligence, and office information systems with multimedia documents is the support of application evolution of object schemas as well as evolution of objects in the application. We provided a framework of schema evolution in [BKKK86, BKKK87] and the framework was realized in an object-oriented database system, ORION, at MCC. In this paper, we extend this schema evolution framework by allowing schema versions and DAG rearrangement views in object-oriented databases. We present a technique that enables users to manipulate schema versions explicitly and maintain schema evolution histories. For completeness, we integrate our model with the object version model formulated by H.T. Chou and W. Kim [CK86]. We identify new types of view, called DAG rearraangement views, of composite objects and class hierarchies. We present a set of operators for defining DAG rearrangement views. We identify sets of composite object views with the property that queries on the views are processable on instances of the original composite object schema. We also discuss how instances would be viewed and reorganized in DAG rearrangement views of class hierarchies.
Optimum design of cable-stayed bridges with imprecise data
Authors: L. M. C. Simões, J. H. Negrão
Venue: Proceedings of the eighth international conference on The application of artificial intelligence to civil and structural engineering computing (2001)

This work presents the Two-phase method for fuzzy optimization of cable stayed bridges. The minimization problem is stated as the minimization of stresses, displacements and bridge cost. A finite-element approach is used for structural analysis. It includes a direct analytic sensitivity analysis module, which provides the structural behaviour responses to changes in the design variables. An equivalent multicriteria approach is used to solve the non-differentiable, non-linear optimization problem, turning the original problem into the sequential minimization of unconstrained convex scalar functions, from which a Pareto optimum is obtained. In the first phase the fuzzy solution is obtained by using the Level Cuts Method and in the second phase the crisp solution, which maximizes the membership function of fuzzy decision-making, is found by using the Bound Search Method. Illustrative numerical examples are solved.
Implementation Techniques for Efficient Data-Flow Analysis of Large Programs
Authors: Darren C. Atkinson, William G. Griswold
Venue:  (2001)

Many software engineering tools such as program slicers must perform data-flow analysis in order to extract necessary information from the program source. These tools typically borrow much of their implementation from optimizing compilers. However, since these tools are expected to analyze programs in their entirety, rather than functions in isolation, the time and space performance of the data-flow analyses are of major concern. We present techniques that reduce the time and space required to perform data-flow analysis of large programs. We have used these techniques to implement an efficient program slicing tool for C programs and have computed slices of programs with more than 100,000 lines of code.
Stability of Collocation at Gaussian Points
Authors: Uri Ascher, Bader G.
Venue:  (1984)

Symmetric Runge-Kutta schemes are particularly useful for solving stiff two-point boundary value problems. Such A-stable schemes perform well in many cases, but it is demonstrated that in some instances the stronger property of algebraic stability is required. A characterization of symmetric, algebraically stable Runge-Kutta schemes is given. The class of schemes thus defined turns out not to be very rich: The only collocation schemes in it are those based on Gauss points, and other schemes in the class do not seem to offer any advantage over collocation at Gaussian points.
Stability of computational methods for constrained dynamics systems
Authors: Uri M. Aschre, Linda R. Petzold
Venue:  (1991)

Many methods have been proposed for numerically integrating the differential-algebraic systems arising from the Euler-Lagrange equations for constrained motion. These are based on various problem formulations and discretizations. We offer a critical evaluation of these methods from the standpoint of stability. \nConsidering a linear model, we first give conditions under which the differential-algebraic problem is well-conditioned. This involves the concept of an essential underlying ODE. We review a variety of reformulations which have been proposed in the literature and show that most of them preserve the well-conditioning of the original problem. Then we consider stiff and nonstiff discretizations of such reformulated models. In some cases, the same implicit discretization may behave in a very different way when applied to different problem formulations, acting as a stiff integrator on some formulations and as a nonstiff integrator on others. We present the approach of projected invariants as a method for yielding problem reformulations which are desirable in this sense.
An Environment Theory with Precomplete Negation over Pairs
Authors: James H. Andrews
Venue:  (1986)

A formal semantics of Voda''s Theory of Pairs is given which takes the natural- deduction form of Gilmore''s first-order set theory. The complete proof theory corresponding to this semantics is given. Then, a logic programming system is described in the form of a computational proof theory for the Gilmore semantics. This system uses parallel disjunction and the technique of precomplete negation; these features are shown to make it more complete than conventional logic programming languages. Finally, some alternative formulations are explored which would bring the logic programming system described closer to conventional systems. The semantic problems arising from these alternatives are explored. Included in appendices are the proof of completeness of the complete proof theory, and the environment solution algorithm which is at the heart of precomplete negation over pairs. 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
Combined structural and coastal loads on an offshore pile: a numerical study
Authors: J. A. Eicher, H. Guan, D. S. Jeng
Venue: Proceedings of the eighth international conference on The application of artificial intelligence to civil and structural engineering computing (2001)

Offshore piles have been commonly used as a foundation element of offshore structures, especially large structures such as Tension Leg Platforms (TLP) and Spar. To perform an appropriate design of an offshore pile, the stress distribution within such a large structure becomes a dominating factor and must be considered. In general, the external loading acting on an offshore pile comes from the axial (structural) and lateral forces (wave loading). To produce a more accurate and effective design procedure for offshore foundation systems under axial and lateral wave loads, a finite element analysis is performed to determine the stresses and displacements in a concrete pile under similar loading conditions.
Dynamic Working Set Memory Allocation for Concurrent Processes
Authors: Emile K. Haddad
Venue:  (1990)

The problem of allocating a given total amount of main memory page-frames M(t) available at time t, among a given set of concurrently active processes {P-sub i} is examined. Memory allocation is managed under the working set policy, and it is assumed that M(t) is larger than the total sum of all working-set sizes but less than the sum of distinct pages in {P-sub i}. It is required that each process receive at least an allocation equal to its working-set size and that the excess memory be additionally distributed among the concurrent processes to enhance their performance. The upper and lower bounds on the individual memory allocations for each process are derived. A fair policy for apportioning the excess memory among the concurrent processes is presented. A procedure for rounding off fragmented page apportionment is described. An application example, illustrating dynamically changing conditions in the concurrent active processes, is described.
Linear Constraint Databases
Authors: Stephane Grumbach, Jianwen Su, Cristophe Tollu
Venue:  (1995)

We give an AC/sup 0/ upper bound on the complexity of first-order queries over (infinite) databases defined by restricted linear constraints. This result enables us to deduce the non-expressibility of various usual queries, such as the parity of the cardinality of a set or the connectivity of a graph in first-order logic with linear constraints over the reals.
Tentative Prune- and- Search Fixed-Points with Applications to Geometric Computation
Authors: D. Kirkpatrick, J. Snoeyink
Venue:  (1993)

Tentative Prune-and-Search for Computing Fixed-Points with Applications to Geometric Computation Motivated by problems in computational geometry, we investigate the complexity of finding a fixed-point of the composition of two or three continuous functions that are defined piecewise. We show that certain cases require nested binary search taking Theta(log^2(n)) time. Others can be solved in logarithmic time by using a prune-and-search technique that may make tentative discards and later revoke or certify them. This work finds application in optimal subroutines that compute approximations to convex polygons, dense packings, and Voronoi vertices for Euclidean and polygonal distance functions.
SCATTERING PARAMETER TRANSIENT ANALYSIS OF INTERCONNECT NETWORKS WITH NONLINEAR TERMINATIONS USING RECURSIVE CONVOLUTION
Authors: Haifang Liao, Wayne W Dai
Venue:  (1993)

A novel method for analyzing interconnect networks with nonlinear terminations is presented. The circuit is partitioned into linear and nonlinear networks. A scattering parameter based macromodel is introduced to model the linear network. An efficient network reduction algorithm is developed to reduce the linear network into a network containing one multiport component (macromodel) together with sources and loads of interest. Exponentially Decayed Polynomial Functions (EDPF) are used to approximate the scattering parameters of the macromodel, which is always stable for stable circuits. In order to incorporate the macromodel into a SPICE like circuit simulator, a simplified recursive convolution formula is developed and Norton equivalent circuits are derived based on recursive convolution. Experiment results indicate that our method can approach the accuracy of SPICE3e2 with order of magnitudes less computing time.
MODELLING AND ANALYSIS OF A TRANSPORT MULTICAST PROTOCOL
Authors: Alexandre Brandwajn, Serge Fdida
Venue:  (1996)

Point-to-multipoint communication is becoming a major need to handle multimedia applications and co-operative work. Multicast protocols are being designed in order to extend reliable transfer of information to multipoint configurations. Such protocols have to cope with several issues such as implosion of control packets that limits scalability or error management mechanisms to provide a reliable delivery of information to the end user. Most of these protocols are sensitive to the network environments and the parameters used to control the exchange of information. It is therefore mandatory to properly size these parameters in order to operate the protocol efficiently. Performance analysis is then required. We consider a multicast algorithm akin to the bucket algorithm proposed in XTP3.6. We develop a queueing model that allows us to represent the key features of the proposed protocol, and assist in properly sizing its parameters. We discuss the model accuracy, and analyze the results as a function of various network environments.
Construction of File Management Systems From Software Components
Authors: Don S. Batory
Venue:  (1988)

We present an approach for developing building-block technologies for mature software domains. It relies on indepth studies of existing systems, published algorithms and structures to discern generic architectures for large classes of systems. An architecture is a template in which building-blocks can be plugged. Interfaces are standardized to make blocks interchangable. In this paper we describe our most recent prototype, a file management system (FMS) synthesizer. The synthesizer enables a customized FMS to be assembled from prewritten components in minutes at little cost. Writing the same FMS from scratch requires man-years of effort and hundreds of thousands of dollars.
Preconditioned Kaczmarz-Extended Algorithm with Relaxation Parameters
Authors: C. Popa
Venue:  (1997)

We analyze in this paper the possibility of using classical preconditioning techniques for square non-singular systems, also in the case of inconsistent least-squares problems. We find conditions in which the preconditioned least-squares problem is connected to the initial one, in a simple way, by the preconditioning matrices. We also find conditions such that the Kaczmarz-Extended algorithm with relaxation parameters (analyzed by the author in a previous paper), can be adapted to the preconditioned least-squares problem. In the last section of the paper we present numerical experiments, with two variants of preconditioning, applied to a full-rank, inconsistent linear least-squares model problem. 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
The Pagenumber of Genus g Graph is 0(g)
Authors: Lenwood S. Heath, Sorin Istrail
Venue:  (1990)

In 1979, Berhart and Kainen conjectured that graphs of fixed genus g greater than or equal to 1 have unbounded pagenumber. This proves that genus g graphs can be embedded in 0(g) pages, thus disproving the conjecture. An Omega(square root of g) lower bound is also derived. The first algorithm in the literature for embedding an arbitrary graph in a book with a non-trivial upper bound on the number of pages is presented. First, the algorithm computes the genus g of a graph using the algorithm of Filotti, Miller, Reif (1979), which is polynomial-time for fixed genus. Second, it applies an optimal-time algorithm for obtaining an 0(g)-page book embedding. We give separate book embedding algorithms for the cases of graphs embedded in orientable and nonorientable surfaces. An important aspect of the construction is a new decomposition algorithm, of independent interest, for a graph embedded on a surface. Book embedding has application in several areas, two of which are directly related to the results obtained: fault-tolerant VLSI and complexity theory.