ppxscal/embedding_network huggingface dataset:
Model \& Solution Strategy for Placement of Rectangular Blocks in the Euclidean Plane
Authors: Amir Alon, Uri Ascher
Venue:  (1986)

This paper describes a nonlinear optimization model for the placement of rectangular blocks with some wire connections among them in the Euclidian plane, such that the total wire length is minimized. Such a placement algorithm is useful as a CAD tool for VLSI and PCB layout designs. The mathematical model presented here ensures that the blocks will not overlap and minimizes the sum of the distances of the interconnections of the blocks with respect to their orientation as well as their position. We also present mechanisms for solving more restrictive placement problems, including one in which there is a set of equally spaced, discrete angles to be used in the placement. The mathematical model is based on the Lennard-Jones 6-12 potential equation, on a sine wave shaped penalty function, and on minimizing the sum of the squares of the Euclidian distances of the block interconnections. We also present some experimental results which show that good placements are achieved with our techniques.
The three-dimensional beam theory: finite element formulation based on curvature
Authors: D. Zupan, M. Saje
Venue: Proceedings of the eighth international conference on The application of artificial intelligence to civil and structural engineering computing (2001)

A new finite element formulation of the 'geometrically exact finite-strain beam theory' is presented. The formulation employs the generalized virtual work principle in which the main role is played by the pseudo-curvature vector. The solution of the governing equations is obtained by using a combined Galerkin-collocation algorithm. The collocation assures that the equilibrium and the constitutive internal force and moment vectors are equal at a set of the chosen discrete points. A special update procedure for the pseudo-curvature and rotation vectors is employed in Newton's iteration because of the non-linearity of the configuration space. The accuracy and the efficiency of the derived numerical algorithm are demonstrated by several examples.
A Tight Lower Bound on the Cover Time for Random Walks on Graphs
Authors: U. Feige
Venue:  (1993)

We prove that the expected time for a random walk to cover all n vertices of a graph is at least (1+o(1))n&#x00A0;1n&#x00A0;n. 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
PROBABLY APPROXIMATELY CORRECT LEARNING
Authors: David Haussler
Venue:  (1990)

This paper surveys some recent theoretical results on the efficiency of machine learning algorithms. The main tool described is the notion of Probably Approximately Correct (PAC) learning, introduced by Valiant. We define this learning model and then look at some of the results obtained in it. We then consider some criticisms of the PAC model and the extensions proposed to address these criticisms. Finally, we look briefly at other models recently proposed in computational learning theory.
Gene expression and scalable genetic search
Authors: Hillol Kargupta
Venue: Advances in evolutionary computing: theory and applications (2003)

Gene expression evaluates the genetic fitness of an organism through a sequence of representation transformations (DNA→mRNA→Protein). Moreover it does so in a very distributed and decomposed fashion by evaluating different portions of the DNA in order to produce various proteins in different body cells. This chapter reviews some of the recent results that underscore the possible critical role of gene expression in scalable genetic search. It considers a Fourier basis representation to analyze genetic fitness functions and shows that polynomial-time construction of a decomposed representation in the Fourier basis is possible when the function has a polynomial-size description. It also points out that genetic code-like transformations may offer us a unique technique to transform some functions of exponential description in the Fourier basis to an exponentially long representation with only a polynomial number of terms that are exponentially more significant than the rest. This may be useful for a polynomial-time approximation of an exponential description. Since the construction of decomposed representation of functions from observed data plays an important role in machine learning, data mining, and black-box optimization, the role of gene expression in scalable genetic search appears quite critical.
Data Types as Term Algebras
Authors: K, Akira a, Karl Abrahamson
Venue:  (1983)

Data types in programming have been mathematically studied from two different viewpoints, namely data types as (initial) algebras and data types as complete partial orders. In this paper, we explore a possibility of finitaristic approach. For finitarists, the only sets accepted are ``recursively defined'''' sets. We observe that recursive definition not only defines a set of terms but also basic operations over them, thus it induces an algebra of terms. We compare this approach to the existing two approaches. Using our approach we present finer classification of data types.
The Synergy Between Object-Oriented Programming and Open System Interconnection
Authors: Gregory R. Lavender, Dennis G. Kafura
Venue:  (1991)

The software engineering practice of building distributed object-oriented applications can be improved dramatically by exploiting the powerful synergism between object-oriented programming (OOP) and Open System Interconnection (OSI). The synergy arises because there are corresponding and complementary elements in both OOP and OSI; these elements are detailed and the synergism resulting from their integration is explained. The architecture of a prototype implementation, the goal of Project Synergy, is described. The environment created by Project Synergy supports application development using classes which are defined in an implementation-independent manner, implemented in possibly different programming languages, and executed in a distributed system on possibly heterogeneous processor architectures.
STOCHASTIC CONTEXT-FREE GRAMMARS FOR MODELING THREE SPLICEOSOMAL SMALL NUCLEAR RIBONUCLEIC ACIDS (Masters Thesis)
Authors: Rebecca Underwood
Venue:  (1994)

In this thesis, stochastic context-free grammars (SCFGs) are applied to the problems of folding, aligning and modeling families of homologous RNA sequences---specifically, the small nuclear RNA sequences of the spliceosome. SCFGs generalize the hidden Markov models (HMMs) used in related work on protein and DNA to capture the sequences'' common primary and secondary structure. This thesis discusses a recently introduced algorithm, Tree-Grammar EM, for deducing SCFG parameters automatically from unaligned, unfolded training sequences [SBU+93, SBM+94, SBH+94a] and demonstrates its application to modeling three of the five prominent trans-acting factors in spliceosomal small nuclear RNA: U1, U5 and U6. Tree-Grammar EM, a generalization of the HMM forward-backward algorithm, is based on tree grammars and is faster than the previously proposed inside-outside SCFG training algorithm. Results show that after having been trained on as few as about 20 snRNA sequences, each of the three models can discern snRNA sequences from similar-length RNA sequences of other kinds, can find secondary structure of new snRNA sequences and can produce multiple alignments of snRNA sequences.
Improved Genetic Algorithm for the Design of Stiffened Composite Panels
Authors: S. Nagendra, D. Jestin, Z. Gurdal, Robert T. Haftka, Layne T. Watson
Venue:  (1994)

The design of composite structures against buckling presents two major challenges to the designer. First, the problem of laminate stacking sequence design is discrete in nature, involving a small set of fiber orientations, which complicates the solution process. Therefore, the design of the stacking sequence is a combinatorial optimization problem which is suitable for genetic algorithms. Second, many local optima with comparable performance may be found. Most optimization algorithms find only a single optimum, while often a designer would want to obtain all the local optima with performance close to the global optimum. Genetic algorithms can easily find many near optimal solutions. However, they usually require very large computational costs. Previous work by the authors on the use of genetic algorithms for designing stiffened composite panels revealed both the above strength and weakness of the genetic algorithm. The present paper suggests several changes to the basic genetic algorithm developed previously, and demonstrates reduced computational cost and increased reliability of the algorithm due to these changes. Additionally, for a stiffened composite panel used in this study, designs lighter by about 4 percent compared to previous results were obtained.
Evaluating Weak Memories with Maya
Authors: Divyakant Agrawal, Manhoi Choy, Hong V Leong, Ambuj K. Singh
Venue:  (1994)

Maya is a simulation platform for evaluating the performance of parallel programs on parallel architectures with different memory coherence protocols. Rapid prototyping of different memory protocols supporting varying degrees of coherence is possible and the impact of these protocols on the performance of application programs can be studied. Implementations of existing weak memories along with some new primitives using Maya are presented. The results of running some user applications are summarized and the impact of weak memories on the efficiency of parallel programs is discussed.
Using Embedded Network Processors to Implement Global Memory Management in a Workstation Cluster
Authors: Yvonne Coady, Joon S Ong, Michael J. Feeley
Venue:  (1999)

Advances in network technology continue to improve the communication performance of workstation and PC clusters, making high-performance workstation-cluster computing increasingly viable. These hardware advances, however, are taxing traditional host-software network protocols to the breaking point. A modern gigabit network can swamp a host''s IO bus and processor, limiting communication performance and slowing computation unacceptably. Fortunately, host-programmable network processors used by these networks present a potential solution. Offloading selected host processing to these embedded network processors lowers host overhead and improves latency. This paper examines the use of embedded network processors to improve the performance of workstation-cluster global memory management. We have implemented a revised version of the GMS global memory system that eliminates host overhead by as much as 29% on active nodes and improves page fault latency by as much as 39%.
Fuzzy Functional Programming
Authors: Gary Meehan
Venue:  (1997)

This report aims to motivate the implementation of fuzzy logic in functional programming in a variety of areas. It includes reasoning using fuzzy logic and fuzzy subsets. and fuzzy expert systems. We show that a functional environment is a natural setting for fuzzy logic, yielding fuzzy programs that are compact, neat, readable and easily adaptable.
The Support Function, Curvature Functions and 3-D Attitude
Authors: Ying Li, Robert J. Woodham
Venue:  (1992)

Attitude determination finds the rotation between the coordinate system of a known object and that of a sensed portion of its surface. Orientation-based representations record 3-D surface properties as a function of position on the unit sphere. They are useful in attitude determination because they rotate in the same way as the object rotates. Three such representations are defined using, respectively, the support function and the first and second curvature functions. The curvature representations are unique for smooth, strictly convex objects. The support function representation is unique for any convex object. The essential mathematical basis for these representations is provided. The paper extends previous results on convex polyhedra to the domain of smooth, strictly convex surfaces. Combinations of the support function of a known object with curvature measurements from a visible surface transform attitude determination into an optimization problem for which standard numerical solutions exist. Dense measurements of surface curvature are required. Surface data can be obtained from laser range finding or from shape-from-shading methods, including photometric stereo. A proof-of-concept system has been implemented and experiments conducted on a real object using surface orientation and surface curvature data obtained directly from photometric stereo.
SWIFT/RAID: A DISTRIBUTED RAID SYSTEM
Authors: D. D.E. Long, Bruce R. Montague, Luis Cabrera
Venue:  (1994)

The Swift I/O architecture is designed to provide high data rates in support of multimedia type applications in general purpose distributed environments through the use of distributed striping. Striping techniques place sections of a single logical data space onto multiple physical devices. The original Swift prototype was designed to validate the architecture, but did not provide fault tolerance. We have implemented a new prototype of the Swift architecture that provides fault tolerance in the distributed environment in the same manner as RAID levels 4 and 5. RAID (Redundant Arrays of Inexpensive Disks) techniques have recently been widely used to increase both performance and fault tolerance of disk storage systems. The new Swift/RAID implementation manages all communication using a distributed transfer plan executor which isolates all communication code from the rest of Swift. The transfer plan executor is implemented as a distributed finite state machine which decodes and executes a set of reliable data transfer operations. This approach enabled us to easily investigate alternative architectures and communications protocols. Providing fault tolerance comes at a cost, since computing and administering parity data impacts Swift/RAID data rates. For a five node system, in one typical performance benchmark, Swift/RAID level 5 obtained 87% of the original Swift read throughput and 53% of the write throughput. Swift/RAID level 4 obtained 92% of the original Swift read throughput and 34% of the write throughput.
Mathematical Foundation for Orientation Based Representations of Shape
Authors: Ying Li
Venue:  (1990)

Mathematical foundations for orientation based shape representation are reviewed. Basic tools include support function, mixed volume, vector addition, Blaschke addition, and the corresponding decompositions, as well as some basic facts about convex bodies, are presented. Results on several types of curvature measures such as spherical images, m-th order area functions are summarized. As a case study, the EGI approach is examined to see how the classical results on Minkowski''s problem are utilized in computational vision. Finally, results on Christoffel''s problem are surveyed, including constructive proofs. 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
A Light-Weight Framework for Hardware Verification
Authors: Christoph Kern, Tarik Ono-Tesfaye, Mark R. Greenstreet
Venue:  (1999)

We present a deductive verification framework that combines deductive reasoning, general purpose decision procedures, and domain-specific reasoning. We address the integration of formal as well as informal domain-specific reasoning, which is encapsulated in the form of user-defined inference rules. To demonstrate our approach, we describe the verification of a SRT divider where a transistor-level implementation with timing is shown to be a refinement of its high-level specification.
The Use of Complexity Metrics Throughout the Software Lifecycle
Authors: Sallie M. Henry, Steven A. Wake, Wei Li
Venue:  (1992)

Software metrics attempt to uncover difficult or complex components of a software system. The hypothesis is that complex components are more difficult to understand, hence they are hard to maintain and more prone to error. Discovery of these complex components can aid the software developer in selecting which components to redesign, direct the testing effort, and indicate the maintenance effort required. Previous studies have demonstrated two main concepts: (1) there exists a high correlation between design complexity and source code complexity, and (2) metrics applied to source code have a high correlation to the maintenance activity needed. This previous research motivates us to develop a methodology which uses complexity metrics throughout the software life cycle. Programmer productivity may be increased and software development cost may be reduced if error prone software is discovered early in the life cycle.
Extracting evolution of web communities from a series of web archives
Authors: Masashi Toyoda, Masaru Kitsuregawa
Venue: Proceedings of the fourteenth ACM conference on Hypertext and hypermedia (2003)

Recent advances in storage technology make it possible to store a series of large Web archives. It is now an exciting challenge for us to observe evolution of the Web. In this paper, we propose a method for observing evolution of web communities. A web community is a set of web pages created by individuals or associations with a common interest on a topic. So far, various link analysis techniques have been developed to extract web communities. We analyze evolution of web communities by comparing four Japanese web archives crawled from 1999 to 2002. Statistics of these archives and community evolution are examined, and the global behavior of evolution is described. Several metrics are introduced to measure the degree of web community evolution, such as growth rate, novelty, and stability. We developed a system for extracting detailed evolution of communities using these metrics. It allows us to understand when and how communities emerged and evolved. Some evolution examples are shown using our system.
The estimation of the WCET in super-scalar real-time system
Authors: Hassan Aljifri, Alexander Pons, Moiez Tapia
Venue: Real-time system security (2003)

Predicting and estimating the execution time of a program is of the utmost importance to designers of real-time systems, particularly hard real-time systems. This paper describes an algorithm for estimating an improved WCET (worst-case execution time) of a real-time program that utilizes a path generating approach to factor into the calculation the effects of super-scalar processor pipelining. The algorithm starts by determining the program's control flow. The pipelining analysis takes into account the simultaneous execution of instructions in distinct blocks in two separate pipelines. The timing tool uses the pipelining analysis to estimate the WCET. The results indicate that this method enhances the acquisition of tighter estimates.
An Efficient Implementation of the Quorum Consensus Protocol
Authors: M. L. Liu, D. Agrawal, A. E Abbadi
Venue:  (1994)

The Quorum Consensus(QC) algorithm, a replication control algorithm which provides serializability even in the presence of network partitioning, has been studied extensively but is not widely implemented in practice. One of the reasons for its lack of acceptance is that the gathering of a quorum for each operation in a transaction is non-trivial to implement. The typical approach is either (i) to send each operation to all replica sites and wait for a quorum of sites to respond, or (ii) to send each operation to a random quorum set, then retry if not all responses are received after a timeout. Both alternatives are difficult to implement. This paper proposes a simple implementation approach which makes use of an estimated uplist at the site of a transaction coordinator. Such a list provides a hint on which replica sites are currently communicable. We argue that such a list is typically maintained for systems on modern-day networks for fault tolerance and/or network routing. Using such a list, a transaction coordinator dispatches an operation to a quorum set whose members are communicable. The operation is successful if all members respond in time; otherwise, it has failed and the transaction is subsequently aborted. The implementation of this algorithm is straightforward. Our simulation results indicate that it yields better response time and throughput when compared with the typical implementation approaches, and at the same time it provides comparable data availability.
Global Optimization for Mapping Parallel Image Processing Tasks on Distributed Memory Machines
Authors: Cheolwhan Lee, Yuan Wang, Tao Yang
Venue:  (1996)

Many parallel algorithms and library routines are available for performing computer vision and image processing (CVIP) tasks on distributed-memory multiprocessors. The typical image distribution may use column, row, and block based mapping. Integrating a set of library routines for a CVIP application requires a global optimization for determining the data mapping of individual tasks by considering inter-task communication. The main difficulty in deriving the optimal image data distribution for each task is that CVIP task computation may involve loops, and the number of processors available and the size of the input image may vary at the run time. In this paper, a CVIP application is modeled using a task chain with nested loops, specified by conventional visual languages such as Khoros and Explorer. A mapping algorithm is proposed that optimizes the average run-time performance for CVIP applications with nested loops by considering the data redistribution overheads and possible run-time parameter variations. A taxonomy of CVIP operations is provided and used for further reducing the complexity of the algorithm. Experimental results on both low-level image processing and high-level computer vision applications are presented to validate this approach.
A Task Scheduling Algorithm for Minimum Busiest Procesor Idle Time
Authors: Emile K. Haddad
Venue:  (1993)

This paper provides a heuristic to minimize the idle time of the busiest processor in a system in which the number of modules to be executed by every processor has been predetermined for a given precedence graph. Except for the busiest processor, the assignment of modules to the other processors is done as evenly as possible. Each of the modules involved is of unit size. An exhaustive enumeration solution of the problem is of NP-complete complexity. The heuristic presented in this paper is of polynomial time.
Projective reconstruction from curve correspondences in uncalibrated views
Authors: Hanns Schulz-Mirbach, I. Weiss
Venue:  (1994)

This paper presents algorithms for stereo reconstruction from uncalibrated binocular stereo views using correspondences of curves between the two images. We mainly consider curves which are projections of planar 3-D curves although some of our methods work without this restriction as well. First a brief description of reconstruction algorithms based on point correspondences is given. Then we introduce a coordinate system which is invariant to the unknown camera parameters. Compared to similar constructions reported in the literature our method has the advantage that no restrictions concerning the relative position of the cameras (e.g. parallel optical axes) are necessary. Using this coordinate system we show how to reduce the reconstruction from conic correspondences to the point based case. Next the case of general curves is considered. By applying a simple tangent construction we obtain for a given pair of corresponding curves at least two pairs of matching curve points. By fitting at these points an osculating conic we get pairs of matching conics which reduces the problem to conics based stereo reconstruction. All these algorithms rely on the assumption that the epipolar geometry (encoded in the fundamental matrix) is known. We discuss how to recover the epipolar geometry from conic correspondences. The appendix contains some useful results concerning normal forms of pairs of conics.