ppxscal/embedding_network huggingface dataset:
Localization and Homing Using Combinations of Model Views
Authors: R. Basri, E. Rivlin
Venue:  (1994)

Navigation involves recognizing the environment, identifying the current position within the environment, and reaching particular positions. We present a method for Localization (the act of recognizing the environment), positioning (the act of computing the exact coordinates of a robot in the environment), and homing (the act of returning to a previously visited position) from visual input. The method is based on representing the scene as a set of 2D views and predicting the appearances of novel views by linear combinations of the model views. The method accurately approximates the appearance of scenes under weak-perspective projection. Analysis of this projection as well as experimental results demonstrate that in many cases this approximation is invalid, either a large number of models can be acquired or an iterative solution to account for the perspective distortions can be employed. The method has several advantages over other approaches. It uses relatively rich representations; the representations are 2D rather than 3D; and localization can be done from only a single 2D view without calibration. The same principal method is applied for both the localization and positioning problems, and a simple ``qualitative'''' algorithm for homing is derived from this method.
Heuristics for Scheduling Parameter Sweep Applications in Grid Environments
Authors: Henri Casanova, Arnaud Legrand, Dmitrii Zagorodnov, Fran Berman
Venue:  (1999)

The computational Grid provides a promising platform for the efficient execution of parameter sweep applications over very large parameter spaces. Scheduling such applications is challenging because target resources are heterogeneous, because their load and availability varies dynamically, and because tasks may share common data files. In this paper, we propose a scheduling algorithm for parameter sweep applications on the Grid. We consider standard heuristics for task/host assignment (Max-min, Min-min, Sufferage), and we propose an extension of Sufferage called XSufferage. Using simulation, we demonstrate 3 results: 1) that XSufferage can take advantage of file sharing to achieve better performance than the other heuristics under a wide variety of load conditions, 2) that it is possible to characterize the environments under which different heuristics perform best, and 3) that it is possible to characterize the performance of different heuristics under the (realistic) assumption of varying accuracy of performance estimations.
PROTECTING REPLICATED OBJECTS AGAINST MEDIA FAILURES
Authors: Jehan Paris, Darrell D.E. Long
Venue:  (1990)

We present a replication control protocol that provides excellent data availabilities while guaranteeing that all writes to the object are recorded in at least two replicas. The protocol, *robust dynamic voting* (RDV) accepts reads and writes as long as at least two replicas remain available. The replicated object remains inaccessible until either the two last available replicas recover or one of the two last available replicas can collect the votes of a majority of replicas. We evaluate the read and write availabilities of replicated data objects managed by the RDV protocol and compare them with those of replicated objects managed by majority consensus voting, dynamic voting and hybrid dynamic voting protocols. We show that RDV can provide extra protection against media failures with no significant loss of availability.
Randomized Function Evaluation on a Ring
Authors: Karl Abrahamson, Andrew Adler, Lisa Higham, David G. Kirkpatrick
Venue:  (1987)

Let $R$ be a unidirectional asynchronous ring of $n$ processors each with a single input bit. Let $f$ be any cyclic non-constant function of $n$ boolean variables. Moran and Warmuth [8] prove that any deterministic algorithm for $R$ that evaluates $f$ has communication complexity $\Omega (n \log n)$ bits. They also construct a cyclic non-constant boolean function that can be evaluated in $O(n \log n)$ bits by a deterministic algorithm. This contrasts with the following new results: \begin{enumerate} \item There exists a cyclic non-constant boolean function which can be evaluated with expected complexity $O (n \sqrt{\log n})$ bits by a randomized algorithm for $R$. \item Any nondeterministic algorithm for $R$ which evaluates any cyclic non-constant function has communication complexity $\Omega (n \sqrt{\log n})$ bits. \end{enumerate
Exploring the predictable
Authors: Jürgen Schmidhuber
Venue: Advances in evolutionary computing: theory and applications (2003)

Details of complex event sequences are often not predictable, but their reduced abstract representations are. I study an embedded active learner that can limit its predictions to almost arbitrary computable aspects of spatio-temporal events. It constructs probabilistic algorithms that (1) control interaction with the world, (2) map event sequences to abstract internal representations (IRs), (3) predict IRs from IRs computed earlier. Its goal is to create novel algorithms generating IRs useful for correct IR predictions, without wasting time on those learned before. This requires an adaptive novelty measure which is implemented by a co-evolutionary scheme involving two competing modules collectively designing (initially random) algorithms representing experiments. Using special instructions, the modules can bet on the outcome of IR predictions computed by algorithms they have agreed upon. If their opinions differ then the system checks who's right, punishes the loser (the surprised one), and rewards the winner. An evolutionary or reinforcement learning algorithm forces each module to maximize reward. This motivates both modules to lure each other into agreeing upon experiments involving predictions that surprise it. Since each module essentially can veto experiments it does not consider profitable, the system is motivated to focus on those computable aspects of the environment where both modules still have confident but different opinions. Once both share the same opinion on a particular issue (via the loser's learning process, e.g., the winner is simply copied onto the loser), the winner loses a source of reward -- an incentive to shift the focus of interest onto novel experiments. My simulations include an example where surprise-generation of this kind helps to speed up external reward.
Constraint Satisfaction Channel Routing
Authors: A. Wilk
Venue:  (1996)

This paper presents a new polynomial approximation algorithm for constraint-based channel routing. The algorithm benefits from the model and techniques used in temporal constraint satisfaction problems. The algorithm presented is an efficient 2-layer track by track channel router that was also extended to handle three layers. Excellent results for a variety of benchmark examples were obtained. 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
Collapsing the Resultant Dipole System
Authors: Alexander P. Morgan, Andrew J. Sommese, Layne T. Watson
Venue:  (1987)

In this paper we show how to reduce the resultant dipole system developed by Gabor, Hodgkin, and Nelson to a single quadratic equation. This system was developed to determine the resultant dipole of the heart from measurements on the body surface. Reducing the system to a quadratic equation eliminates previous difficulties in numerically solving the system.
Computational embryology: past, present and future
Authors: Sanjeev Kumar, Peter J. Bentley
Venue: Advances in evolutionary computing: theory and applications (2003)

This chapter describes research into the new field of computational embryology. It starts with a look at the past, examining the contributions scientists have made over the years that have caused the gradual amalgamation of embryology and genetics into developmental biology. This is followed by a detailed investigation into the evolution of computational embryogenies. The focus of this chapter is on the two most promising types of computational embryogeny, explicit and implicit, investigating the evolvability and scalability of both for morphogenesis. The problem set is that of evolving certain predefined shapes - letters of the alphabet. The results show that both embryogenies are good at defining different morphologies, but significantly, the implicit embryogeny incurs no increase in genotype size as the problem is scaled. Finally, the chapter ends with a description of a more biologically plausible model of aspects of biological development.
ACT++: Building a Concurrent C++ with Actors
Authors: Dennis G. Kafura, Keung H Lee
Venue:  (1989)

ACT++ (Actors in C++) is a concurrent object-oriented language being designed for distributed real-time applications. The language is a hybrid of the actor kernel language and the object-oriented language C++. The concurrency abstraction of ACT++ is derived from the actor model as defined by Agha. This paper discusses our experience in building a concurrent extension of C++ with the concurrency abstraction of the actor model. The current design of ACT++ and its implementation are described. Some problems found in the Agha''s actor model are discussed in the context of distributed real-time applications. The use of ACT++ disclosed the difficulty of combining the actor model of concurrency with class inheritance in an object-oriented language.
Explicit Parallel Programming: User''s Guide
Authors: Jim Gamble, Calvin J. Ribbens
Venue:  (1991)

The Explicit Parallel Programming (EPP) language is defined and illustrated with several examples. EPP is a prototype implementation of a language for writing parallel programs for shared memory multiprocessors. EPP may be viewed as a coordination language, since it is used to define the sequencing or ordering of various tasks, while the tasks themselves are defined in some other compilable language. The prototype described here requires FORTRAN as the base language, but there is no inherent reason why some other imperative language could not be used instead. EPP encourages a structured and readable style of writing parallel programs, and it allows virtually any type of parallelism to be expressed. It maintains as strict a separation as possible between the two main components of a parallel program: semantic actions and logic sequencing. This paper is intended for the first-time user of EPP.
The Renormalized Curvature Scale Space and the Evolution Properties of Planar Curves
Authors: Alan K. Mackworth, Farzin Mokhtarian
Venue:  (1987)

The Curvature Scale Space Image of a planar curve is computed by convolving a path-based parametric representation of the curve with a Gaussian function of variance $\sigma^{2}$, extracting the zeroes of curvature of the convolved curves and combining them in a scale space representation of the curve. For any given curve $\Gamma$, the process of generating the ordered sequence of curves \{ \( \Gamma_{\sigma} \mid \sigma \geq 0\) \} is known as the evolution of $\Gamma$. It is shown that the normalized arc length parameter of a curve is, in general, not the normalized arc length parameter of a convolved version of that curve. A new method of computing the curvature scale space image reparametrizes each convolved curve by its normalized arc length parameter. Zeroes of curvature are then expressed in that new parametrization. The result is the Renormalized Curvature Scale Space Image and is more suitable for matching curves similar in shape. Scaling properties of planar curves and the curvature scale space image are also investigated. It is shown that no new curvature zero-crossings are created at the higher scales of the curvature scale space image of a planar curve in $C_{2}$ if the curve remains in $C_{2}$ during evolution. Several positive and negative results are presented on the preservation of various properties of planar curves under the evolution process. Among these results is the fact that every polynomially represented planar curve in $C_{2}$ intersects itself just before forming a cusp point during evolution.
A Comparison of Formal Definitions of Ada Tasking
Authors: Xudong He, John A. N. Lee
Venue:  (1989)

In this paper, various formalisms (the operational approach, the denotational approach, the axiomatic approach, Petri nets and temporal logic) are briefly introduced through their applications in formally defining Ada tasking, and their coverages and relative merits are then
Vectorization Experiment on the IBM 3090 Vector Facility
Authors: Joerg R Weimar
Venue:  (1990)

A comparison between sequential code and vectorization code for matrix multiplication is made and the possible ways to vectorize matrix multiplication are examined. The result is that vectorization of the correct loop results in a speedup of almost 3 for vectors that are long enough, i.e., longer than or equal to half the vector length of the machine. The number and order of memory references is a very important factor.
An Efficient Implementation of a Conformal Mapping Method Using the Szego Kernel
Authors: Manfred R. Trummer
Venue:  (1984)

An implementation, based on iterative techniques, of a method to compute the Riemann mapping function is presented. The method has been recently introduced by N. Kerzman and the author; it expresses the Szego kernel as the solution of an integral equation of the second kind. It is shown how to treat symmetric regions. The algorithm is tested on five examples. The numerical results show that the method is competitive, with respect to accuracy, stability, and efficiency.
SEAMAN: Implementing Process-Centered Software DevelopmentEnvironments on Top of an Active Database Management System
Authors: Dimitrios Tombros, Andreas Geppert, Klaus R. Dittrich
Venue:  (1995)

SEAMAN (Software Engineering with Active Mechanisms) is a framework for the efficient construction of process centered software development environments (PCDEs). It consists of a meta-level for the specification of PCDEs and an implementation level consisting of an active object- oriented database system.
The Formal Specification of ELEKTRA
Authors: I. D. Craig
Venue:  (1994)

This paper contains the Z specification of a reflective production rule interpreter.
Energy-reliability trade-off for NoCs
Authors: Davide Bertozzi, Luca Benini, Giovanni De Micheli
Venue: Networks on chip (2003)

Solutions for combined energy minimization and communication reliability control have to be developed for SoC networks. Redundant encodings and error-resilient protocols create new degrees of freedom for trading off energy against realiability and viceversa. In this chapter, the theoretical framework for energy and realiability analysis is introduced and several error control and recovery strategies are investigated in a realistic SoC setting. Furthermore, the chapter provides guidelines and methods to select the most appropriate error control scheme for a given reliability and/or energy efficiency constraint.
Effect of a Sawtooth Boundary on Couette Flow
Authors: Mateescu Gabriel, Wang C.-Y., Ribbens Calvin J., Watson Layne T.
Venue:  (1998)

The relative tagential motion of a smooth plate and a corrugated plate separated by a viscous fluid is studied. The full Navier-Stokes equations are solved using Hermite collocation and Newton''s method. Detailed streamlines and vorticity distributions are determined. The increased drag due to corrugation is found to be substantial.
Textured Image Segmentation Using Multiresolution Markov Random Fields and a Two-component Texture Model
Authors: Chang Li, R. G. Wilson
Venue:  (1997)

In this paper we propose a multiresolution Markov Random Field (MMRF) model for segmenting textured images. The Multiresolution Fourier Transform (MFT) is used to provide a set of spatially localised texture descriptors, which are based on a two-component model of texture, in which one component is a deformation, representing the structural or deterministic elements and the other is a stochastic one. Stochastic relaxation labelling is adopted to maximise the likelihood and assign the class label with highest probability to the block (site) being visited. Class information is propagated from low spatial resolution to high spatial resolution, via appropriate modifications to the interaction energies defining the field, to minimise class-position uncertainty. Experiments on the segmentation of natural textures are used to show the potential of the method.
Processor Lower Bounds for Array Computations with Linear Schedules
Authors: Peter Cappello, Omer Egecioglu
Venue:  (1997)

Using a directed acyclic graph (dag) model of algorithms, this paper treats a problem related to precedence-constrained multiprocessor schedules for array computations: Given a dag and a valid linear schedule for it, compute a lower bound on the number of processors required by the schedule. This is an important practical problem: A good schedule uses time efficiently; a good mapping of nodes to processors uses energy efficiently. The lower bounds obtained are good; we know of no case where they are not exactly tight. Actually, a harder problem is solved: Given a parametrized family of dags and a correspondingly parametrized valid linear schedule, symbolically generate a processor lower bound formula. To visualize the method for computing this formula, the nodes, representing computational tasks, are viewed as a set of lattice points in a convex polyhedron. The number of tasks that are scheduled for execution during any given time step of a linear schedule is the number of non-negative integer solutions to a set of linear Diophantine equations parametrized by the number of nodes of the dag. An algorithm, based on construction of generating functions, is presented for computing these numbers. This is the first such algorithm to be reported. Using this algorithm and a symbolic algebra package, formulas for processor lower bounds are obtained automatically. The algorithm has been implemented as a Mathematica program. Example runs for Matrix-Vector Product, and Triangular Matrix Product problems are given. While widely applicable and elegant, it has worst case exponential running time. This is not surprising however; the simpler computation: ``Are any processors scheduled for a particular time step?'''' which is equivalent to ``Is a particular coefficient of the generating function nonzero?" is already known to be an NP-complete problem.
Receptive Fields for Vision: from Hyperacuity to Object Recognition
Authors: S. Edelman
Venue:  (1995)

Many of the lower-level areas in the mammalian visual system are organized retinoptically, that is, as maps which preserve to a certain degree the topography of the retina. A unit that is a part of such a retinotopic map normally responds selectively to stimulation in a well-delimited part of the visual field, referred to as its receptive field (RF). Receptive fields are probably the most prominent and ubiquitous computational mechanism employed by biological information processing systems. This paper surveys some of the possible computational reasons behind the ubiquity of RFs, by discussing examples of RF-based solutions to problems in vision, from spatial acuity, thorugh sensory coding, to object recognition. 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
Message Length Effects for Solving Polynomial Systems on a Hypercube
Authors: Wolfgang Pelz, Layne T. Watson
Venue:  (1986)

Comparisons between problems solved on uniprocessor systems and those solved on distributed computing systems generally ignore the overhead associated with information transfer from one process to another. This paper considers the solution of polynomial systems of equations via a globally convergent homotopy algorithm on a hypercube and some timing results for different situations.
Improved Bounds for Acyclic Job Shop Scheduling
Authors: U. Feige, C. Scheideler
Venue:  (1998)

In acyclic job shop scheduling problems there are n jobs and m machines. Each job is composed of a sequence of operations to be performed on different machines. A legal schedule is one in which within each job, operations are carried out in order, and each machine performs at most one operation in any unit of time. If D denotes the length of the longest job, and C denotes the number of time units requested by all jobs on the most loaded machine, then clearly lb = max[C,D] is a lower bound on the length of the shortest legal schedule. A celebrated result of Leighton, Maggs and Rao shows that if all operations are of unit length, then there always is a legal schedule of length O(lb), independent of n and m. For the case that operations may have different lengths, Shmoys, Stein and Wein showed that there always is a legal schedule of length [O\tilde](lbloglb). We also show that our new upper bound is essentially best possible, by proving the existence of instances of acyclic job shop scheduling for which the shortest legal schedule is of length [(W)\tilde](lbloglb). This resolves (negatively) a known open problem of whether the linear upper bound of Leighton, Maggs and Rao applies to arbitrary job shop scheduling instances (without the restriction to acyclicity and unit length operations).
Wavelet Radiative Transfer and Surface Interaction
Authors: Robert R. Lewis
Venue:  (1996)

In this work-in-progress paper, we present a solution to the illumination problem that is intermediate between the conventional local and global approaches to illumination. It involves the representation of radiance on a surface as a finite element expansion in terms of wavelets. By expanding in terms of ``Nusselt coordinates'''', we show how irradiance, transport, and surface interaction can be evaluated simply and directly in terms of wavelet coefficients. We present an example of transport.
Neighborhood Expansion Grammars
Authors: John L. Pfaltz
Venue:  (1999)

Phrase structure grammars, in which non-terminal symbols on the left side of a production can be rewritten by the string on the right side, together with their Chomsky hierarch classification, are familiar to computer scientists. But, these gramamars are most effective only to generate, and parse, strings. In this report, we introduce a new kind of grmmar in which the right side of the production is simply appended to the intermediate structure in such a way that the left side becomes its "neighborhood" in the new structure. This permits the grammatical definition of many different kinds of "n-dimensional" discrete structures. Several examples are given. Moreover, these grammars yield a formal theory grounded in antimatroid closure spaces. For example, we show that restricted neighborhood expansion grammars capture the essence of finite state and context free phrase structure grammars. 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 Selection Of Mathematical Board Games
Authors: A. S. Fraenkel
Venue:  (1999)

A selection of mathematical games of increasing complexity is presented. It illustrates the complexity ascent from the easy game of nim to the seemingly hard game of chess.