ppxscal/embedding_network huggingface dataset:
A Reconfigurable Processor for Petri Net Simulation
Authors: John Morris, Gary A Bundell, Sonny Tham
Venue:  (1999)

Simulation of systems for the control of large numbers of objects such as traffic flows, network message traffic, etc is CPU intensive and may require inordinately long runs on conventional sequential processors. This work describes the Achilles reconfigurable processor and techniques for programming it to carry out {\PN} simulations. Achilles is an innovative 3-dimensional stack of FPGAs. The 3-D arrangement allows (a) a large number of FPGAs to fit in a small volume, (b) a large degree of flexibility in the way individual devices are interconnected, (c) interconnection with one or more hosts with host-Achilles bandwidth being scaled up to meet requirements and (d) individual stacks to be connected together in a wide variety of patterns so that the computing power of the stack may be scaled as necessary. Bandwidths between the stack and a PC host have been measured at over 30Mbytes/second in the first prototype of the stack: the interconnection is capable of transferring data at PCI bus speeds with the newer, faster FPGAs used in the second prototype currently under construction. This architecture is particularly suitable for {\PN} simulations as hundreds of places in a net can be simultaneously active - reducing by orders of magnitude the time necessary for simulations.
Matrixmultiplikation fur 128-Transputer Parallelrechner ParsytecSuperCluster-128
Authors: Stefan Lupke
Venue:  (1991)

Um Parallelisierungsmoglichkeiten von Algorithmen fur ein rekonfigurierbares 128-Transputer Rechnersystem (T800) zu untersuchen, sind zwei Algorithmen zur parallelen Matrixmultiplikation implementiert worden. Insbesondere sollte festgestellt werden, bis zu welcher Granularitat herab eine Parallelisierung noch effizient ist.
Evolution of strategies for resource protection problems
Authors: William M. Spears, Diana F. Gordon-Spears
Venue: Advances in evolutionary computing: theory and applications (2003)

The objective of this project is to develop effective finite-state machine (FSM) strategies for winning against an adversary in a Competition for Resources simulation. To achieve this goal, we evolve these strategies in a simulated environment and compare a variety of evolutionary methods in this context. Key empirical questions are addressed, such as how many FSM states are optimal, how effective is it to use an evolutionary algorithm that adapts the number of states, and how can one reduce the variance in fitness evaluation? Some of our experimental answers to these questions are quite intriguing. This chapter also explores and evaluates novel algorithms for detecting and repairing deleterious cycles in the evolved FSMs.
Constructing Computer Virus Phylogenies
Authors: L. A. Goldberg, P. W. Goldberg, C. A. Phillips, G. B. Sorking
Venue:  (1996)

There has been much recent algorithmic work on the problem of reconstructing the evolutionary history of biological species. Computer virus specialists are interested in finding the evolutionary history of computer viruses - a virus is often written using code fragments from one or more other viruses, which are its immediate ancestors. A phylogeny for a collection of computer viruses is a directed acyclic graph whose nodes are the viruses and whose edges map ancestors to descendants and satisfy the property that each code fragment is "invented" only once. To provide a simple explanation for the data, we consider the problem of constructing such a phylogeny with a minimum number of edges. In general this optimization problem is NP-complete; some associated approximation problems are also hard, but others are easy. When tree solutions exist, they can be constructed and randomly sampled in polynomial time.
On the Migration of Relational Schemas and Data to Object-OrientedDatabase Systems
Authors: Andreas Behm, Andreas Geppert, Klaus R. Dittrich
Venue:  (1997)

Many organizations have collected large volumes of data which are often stored in relational databases. Now that object-oriented database management systems (OODBMSs) are becoming mature, many organizations also want to benefit from object-oriented technology in general and OODBMSs in particular. One general approach to migrate to object technology is to divide the process into two phases, where the first one transforms the relational into an object-oriented schema and the second one migrates the data into the object-oriented database system. Our approach differs from comparable approaches because it provides assistance in both phases, while other work considers only the first phase. In the first phase we use transformation rules to construct an object-oriented schema which is semantically equivalent to the relational schema. In the second phase, the schema transformation information is used to generate programs that migrate the relational data into an object-oriented database. The concepts of both, schema transformation and data migration are implemented using O2 as the OODBMS.
Diffusion and Wave Propagation in Cellular Automaton Models of Excitable Media
Authors: Joerg R Weimar, John J. Tyson, Layne T. Watson
Venue:  (1991)

In this paper, the authors (1) examine general "masks" as discrete approximations to the diffusion equation, showing how to calculate the diffusion coefficient from the elements of the mask; (2) combine the mask with a thresholding operation to simulate the propagation of waves in excitable media, showing that (for well-chosen masks) the waves obey a linear "speed-curvature" relation with slope given by the predicted diffusion coefficient; and (3) assess the utility of different masks in terms of computational efficiency and adherence to a linear speed-curvature relation.
Software Metrics and the Object-Oriented Paradigm
Authors: Wei Li, Charles Cooley, John A. Lewis, Sallie M. Henry
Venue:  (1990)

Software metrics are in use to guide current software development practices. As commercial organizations make use of the benefits of the object-oriented paradigm, the desire to apply metrics to that paradigm has logically followed. However, standard procedural metrics are limited in their ability to describe true object-oriented designs and code, and in some aspects fail outright. This paper describes the difficulties in applying standard metrics to object-oriented code and defines a set of metrics which are specifically geared toward the features which make the object-oriented approach unique.
Variable Size Block Matching Motion Estimation with Minimal Error
Authors: G. R. Martin, R. A. Packwood, I. Rhee
Venue:  (1995)

Block matching type motion compensation is relatively simple to implement, and thus widely adopted in image sequence coding. Most techniques use fixed-size blocks, and their success relies on the assumption that the motion within each block is uniform. This is not necessarily true, especially if the block size is increased to reduce the number of motion vectors. One solution is to use variable-sized blocks, and a number of schemes have been suggested. The success of variable-size block matching (VSBM) is dependent on an appropriate selection of different size blocks to cover the entire image. Given a fixed number of blocks, in order to obtain the best frame prediction it is necessary to select that set of variable-sized blocks which, when matched with similar blocks in the previous frame, results in the minimum total error. This requirement is difficult to satisfy. Two advances are reported. Firstly an algorithm is described which, based on a quad-tree structure, results in the optimal selection of variable-sized square blocks. It is applied in a VSBM scheme in which the total mean squared error (MSE) is minimized. This provides the best-achievable performance for a quad-tree based VSBM technique. Although it is computationally demanding and hence impractical for real-time codecs, it does provide a yardstick by which the performance of other VSBM techniques can be measured. Secondly, a new VSBM algorithm which adopts a `bottom-up'' approach is described. The technique starts by computing sets of `candidate'' motion vectors for fixed-size small blocks. Blocks are then effectively merged in a quad-tree manner if they have similar motion vectors. The result is a computationally-efficient VSBM technique which performs very well when compared with the optimal algorithm.
Testing strategies for networks on chip
Authors: Raimund Ubar, Jaan Raik
Venue: Networks on chip (2003)

The complexity of Networks-on-Chip (NoC) makes the application of traditional test methods obsolete. For NoC, a combination of methods known from the System-on-Chip, memory and FPGA test areas should be used. That includes functional test, scan test, logic BIST, RAM BIST and testing of interconnect switches and wires. The increasing complexities of systems based on deep-submicron technologies cause two contrary trends: low-level defect-orientation to reach the high reliability of testing and high-level behavioral modeling to reach the efficiency of test generation. Hierarchical approaches seem to be the solution. Built-In Self-Test (BIST) is the main concept for testing the cores in systems on chip. Hybrid BIST containing both hardware and software components is probably the most promising approach to test the nodes of NoC. In densely packaged NoC with embedded memories and reusable cores scan-based approaches, P1500 standard for core test, test access mechanisms, test controt and isolation issues are prospective methods. Testing the NoC interconnect switches and wires is also an important issue.
Finite element modelling of threaded fastener loosening due to dynamic forces
Authors: M. Holland, D. Tran
Venue: Proceedings of the eighth international conference on The application of artificial intelligence to civil and structural engineering computing (2001)

Threaded fasteners are still produced in large quantities to be used for fastening in engineering structures. It is well known that when they are subjected to dynamic loads due to impact or vibration they can become loosened, resulting in failure of the functioning of the structures or even in catastrophic accidents. The cost of manufacturing and maintenance efforts to overcome fastener loosening under the effects of dynamic loads is quite high. The mechanism of interaction between friction and vibration has not been well understood, mainly because of a great many parameters involved and the nonlinearity of the problem. This paper looks at effects of vibration on the friction between two threaded surfaces subject to preloading by finite element modelling (FEM). A simple model of contact between two mated threads, a block and an inclined plane, is investigated: the system is subjected to transient impact forces in both axial and transverse directions, and harmonic vibration. The relative motion between the block and the incline surface is monitored to study the effect of vibration on the contact between two surfaces.
Reasoning about Changing Information
Authors: P. Blackburn, J. Jaspars, M. de Rijke
Venue:  (1996)

The purpose of these notes is two-fold: (i) to give a reasonably self-contained introduction to a particular approach to theory change, known as the Alchourron-Gaerdenfors-Makinson (AGM) approach and to discuss some of the alternatives and extensions that have been proposed to it over the past few years; (ii) to relate the AGM approach to other `information-oriented'' branches of logic, including intuitionistic logic, non-monotonic reasoning, verisimilitude and modal and dynamic logic.
Reduction of the Search Space for Back Propagation
Authors: Sok G Lim, Paul Hadingham, Mike Alder
Venue:  (1990)

It is well known that the XOR training set can be solved by a three-layer Neural network, in principle, can solve any problem, but the time required for convergence is very great. In order to increase the speed of the algorithm, that is, to speed up the convergence time taken to learn a training set, we exploit a result of K.S. Fu which shows that we can fix the weights at the output stage, thus reducing the size of the search space without affecting the capacity of the net. The theory has been verified experimentally (in 2 dimensions) by comparing the standard Back Propagation algorithm with the modified algorithm with is referred to in this paper as the Simplifies Back Propagation Algorithm. The experiments indicate that the reduction in the search space allows an improvement in convergence time by a factor of 20 for both three-layer and four-layer nets.
An O(n log n) Algorithm for Finding Minimal Perfect Hash Functions
Authors: Edward A. Fox, Lenwood S. Heath, Qi Chen
Venue:  (1989)

We describe the first practical algorithm for finding minimal perfect hash functions that can be used to access very large databases. This method extends earlier work wherein an O(n3) algorithm was devised, building upon prior work by Sager that described an O(n4) algorithm. Our new O(n log n) expected time algorithm makes use of three key insights: applying randomness whereever possible, ordering our search for hash functions based on the degree of the vertices in a graph that represents word dependencies, and viewing hash value assignment in terms of adding circular patterns of related words to a partially filled disk. While ultimately applicable to a wide variety of data and file access needs, this algorithm has already proven useful in aiding our work in improving performance of CD-ROM systems and our construction of a Large External Network Database (LEND) for semantic networks and hypertext/hypermedia collections. Virginia Disc One includes a demonstration of a minimal perfect hash function running on a PC to access a 130,198 word list on that CD-ROM, and several other microcomputer, minicomputer, and parallel processor versions and applications of our algorithm have also been developed. Tests with a French word list of 420,878 entries and a library catalog key set with over 1.2 million keys have shown that our methods work with very large databases.
Covering a Set with Arithmetic Progressions is NP-Complete
Authors: Lenwood S. Heath
Venue:  (1989)

This paper defines a new class of set covering problems in which the subsets are implicitly derived from the properties of the set elements. In particular, the set elements are integers and the subsets are finite arithmetic progressions. Both minimum cover and exact cover problems are defined. Both problems are shown to be NP-Complete. 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
Cepstral Analysis of Optical Flow
Authors: B, Esf ari, iar, James J. Little
Venue:  (1992)

Visual flow analysis from image sequences can be viewed as detection and retrieval of echoes or repeated patterns in two dimensional signals. In this paper we introduce a new methodology for optical flow analysis based on the cepstral filtering method. Cepstral filtering is a non-linear adaptive correlation technique used extensively in phoneme chunking and echo removal in speech understanding and signal processing. Different cepstral methodologies, in particular power cepstrum, are reviewed and more efficient variations for real image analysis are discussed. Power cepstrum is extended to multiframe analysis. A correlative cepstral technique, cepsCorr, is developed; cepsCorr significantly increases the signal to noise ratio, virtually eliminates errors, and provides a predictive or multi-evidence approach to visual motion analysis.
Abstract Semantics for Module Composition
Authors: Grigore Rosu
Venue:  (2000)

Programmers and software engineers agree in unanimity that a useful characteristic of the programming languages they use for implementations (C++, Java, etc.) is their support for both {\em public} and {\em private} features (types, functions). The public features are often called {\em interfaces}. The private part is not visible outside the module (class, package) that declares it, but it can be used internally to define the visible part. Such distinction helps software engineers abstract their work and ignore details which are a main source of confusion and errors. We claim that the distinction between private and public features might also be a desirable characteristic of formal specifications, not only from the practical point of view but also because of at least two important theoretical reasons. One is the possibility to finitely specify theories which do not admit finite standard presentations. For example, Bergstra and Tucker showed that any recursive algebra is a restriction of an initial algebra presented by a finite number of equations over a larger signature. Another reason is that it allows the user to specify behavioral properties of systems, in the sense that every behavioral specification is equivalent to hiding some operators (i.e., making them private) in a usual specification. We introduce the notion of {\em module specification} as a generalization of the standard specification, having both public (or visible) and private features, and then explore their properties at an abstract level, categorical. To formalize the notion of ``logical system'''' we use {\em institutions} enriched with {\em inclusions}, an abstraction of the natural notion of inclusion of signatures from particular logics. The {\em visible theorems} (or the visible consequences) of a module are those theorems which contain only visible symbols, and a model of that module is a model of its visible consequences. Five basic operations on module specifications are explored: renaming, hiding, enriching, aggregation and parameterization. An internal property of modules, {\em conservativeness}, seems to have a decisive role in giving semantics for module composition.
Least Change Secant Update Methods for Undetermined Systems
Authors: Homer F. Walker, Layne T. Watson
Venue:  (1988)

Least-change secant updates for nonsquare matrices have been addressed recently in [6]. Here we consider the use of these updates in iterative procedures for the numerical solution of underdetermined systems. Our model method is the normal flow algorithm used in homotopy or continuation methods for determining points on an implicitly defined curve. A Kantorovich-type local convergence analysis is given which supports the use of least-change secant updates in this algorithm. This analysis also provides a Kantorovich-type local convergence analysis for least-change secant update methods in the usual case of an equal number of equations and unknowns. This in turn gives a local convergence analysis for augmented Jacobian algorithms which use least-change secant updates. We conclude with the results of some numerical experiments. Key words. underdetermined systems, least-change secant update methods, quasi-Newton methods, normal flow algorithm, augmented Jacobian matrix algorithm, continuation methods, homotopy methods, curve-tracking algorithms, parameter-dependent systems
Task Dependence and Termination in Ada
Authors: Laura K. Dillon
Venue:  (1994)

We use a contour model of Ada tasking to analyze the semantics of task dependence and termination. Our analysis clarifies the complex definitions and rules that determine when procedures and tasks terminate during execution of an Ada program and examines the implications of and possible motivation for the termination rules. We show that the termination rules prevent the premature deallocation of data associated with the runtime-instances of scope units, but that the policy is unnecessarily conservative in this regard. For task instances created by invoking a storage allocator, we show that the conservative termination policy permits more efficient management of heap storage than a less conservative policy. We also examine the impact of the termination rules in Ada on the synchronization of concurrent unit instances. The rules are shown to support both master-slave and client-server applications. In particular, we show how the rules governing distributed termination guarantee that the terminating instances can no longer affect the outcome of a computation. The analysis is intended give programmers a better understanding of Ada of the termination model.
DEBUGGING OPTIMIZED CODE WITHOUT BEING MISLED
Authors: Max Copperman
Venue:  (1993)

Optimizing compilers produce code that impedes source-level debugging. Examples are given in which optimization changes the behavior of a program even when the optimizer is correct, showing that in some circumstances it is not possible to completely debug an unoptimized version of a program. Source-level debuggers designed for unoptimized code may mislead the debugger user when invoked on optimized code. One situation that can mislead the user is a mismatch between where the user expects a breakpoint to be located and the breakpoint''s actual location. A mismatch may occur due to statement reordering or discontiguous code generated from a statement. This work describes a mapping between statements and breakpoint locations that ameliorates this problem. The mapping enables debugger behavior on optimized code that approximates debugger behavior on unoptimized code closely enough that the user need not make severe changes in debugging strategies. This work presents a method of determining when this has occurred, proves the method correct, and shows how a debugger can describe the relevant effects of optimization. The determination method is more general than previously published methods, handling global optimization, flow graph transformations, and not being tightly coupled to optimizations performed by a particular compiler. The information a compiler must make available to the debugger for this task is also described. A third situation that can mislead the user is when optimization has eliminated information in the run-time (procedure activation) stack that the debugger uses (on some architectures) to provide a call stack trace. This work gives several methods of providing the expected stack trace when the run-time stack does not contain this information.
Xaslantest User Manual
Authors: Jeffrey G. Douglas
Venue:  (1994)

Xaslantest is the X-based graphical user interface version of Aslantest, which is a symbolic execution tool for the formal specification language Aslan. Aslan is a state-based specification language built on first-order predicate calculus with equality. Aslantest animates Aslan specifications and enables users to interactively run specific test cases or symbolically execute the specification. This document is the user''s manual for the Xaslantest system, outlining its features and commands.
Two Algorithms for Decision Tree Search
Authors: Runping Qi, David Poole
Venue:  (1992)

In this paper two algorithms for decision tree search are presented. The basic idea behind these algorithms is to make use of domain dependent information, in the form of an evaluation function as that used by AO*, along with a search mechanism similar to the alpha-beta technique for minimax trees. One of the advantages of our algorithms over AO* is that our algorithms need only linear space. The solution computed by the first algorithm can be either optimal or sub-optimal, depending on the admissibility of the evaluation function. The second algorithm is an approximate algorithm which can case a tradeoff between computational efficiency and solution quality. Some results are presented on the correctness of the algorithms and on the quality of the solutions computed by the algorithms.
A New Proof of the NP Completeness of Visual Match
Authors: R. Rensink
Venue:  (1989)

A new proof is presented of Tsotsos'' result [1] that the VISUAL MATCH problem is NP-complete when no (high-level) constraints are imposed on the search space. Like the proof given by Tsotsos, it is based on the polynomial reduction of the NP-complete problem KNAPSACK [2] to VISUAL MATCH. Tsotsos'' proof, however, involves limited-precision real numbers, which introduces an extra degree of complexity to his treatment. The reduction of KNAPSACK to VISUAL MATCH presented here makes no use of limited-precision numbers, leading to a simpler and more direct proof of the result.